Important advances have been made in our understanding of the embryologic origin of the coronary arteries over the last decade. ^, Initially, while the embryonic interventricular communication is still open, the ventricular walls are composed of a trabecular meshwork that allows nourishment of the cardiomyocytes by direct perfusion from the ventricular cavities. As the compact component of the ventricular wall grows, coalescing mural and epicardial vessels are developed. Separately, endocardial sprouts originate from the walls of the aortic root adjacent to the pulmonary trunk and distal to the outflow cushions that will develop the arterial valve cusps and thus high in the aorta. As the aortic root separates from the pulmonary trunk, ongoing growth of the aortic root develops the aortic sinuses and incorporates the orifices of the coronary arteries within the newly formed sinuses, thus moving those origins proximally to below the sinutubular junction. The endocardial sprouts from the aorta then connect with the network of epicardial and mural vessels, thus establishing antegrade coronary blood flow. That is, the proximal coronary arteries grow from the peritruncal area into the aorta with formation of single orifices for left and right coronary arteries. It is for this reason that since the second edition of this book, Dr. John Kirklin and subsequent editors have abandoned the former term anomalous origin or arising from in favor of anomalous connection . The origin of the coronary arteries from the correct sinuses of Valsalva within the aorta is thus partly dependent on the normal separation of the arterial roots and formation of the sinuses.

The anomalous left main coronary artery connects most often to the sinus of Valsalva immediately above the posterior cusp of the pulmonary trunk (from the posterior sinus facing the left coronary sinus) and rarely from that above the lateral cusp (nonfacing sinus). ^, The left main coronary artery is of variable length but usually divides into anterior descending and circumflex branches within 5 or 6 mm of its origin. Collateral communications between right and left coronary arteries are always present but vary in extent. Uncommonly, only the circumflex branch connects anomalously to the pulmonary trunk and rarely only the left anterior descending branch. ^,

Very rarely, the left main coronary artery or only the circumflex artery connects to the right pulmonary artery near its origin rather than to the pulmonary trunk. Even more unusual is the connection of both left and right coronary arteries to the pulmonary trunk (see “ Anomalous Coronary Artery from the Pulmonary Artery in Adults ” under Special Situations and Controversies later in this section).

The left ventricle is always hypertrophied and usually greatly dilated, with dilation often involving primarily the left ventricular apex. Diffuse left ventricular fibrosis is virtually always present, and patients dying in infancy usually have evidence of recent and old anterolateral myocardial infarction. Fibrosis is most marked in the subendocardial layer. Focal calcification may be present in fibrotic areas. Secondary subendocardial fibroelastosis of variable degree is usually present. However, a considerable amount of left ventricular dysfunction, in infants at least, must be ischemic in origin because of dramatic improvement in left ventricular function that can result from an operation that creates a two-artery coronary system. Improved left ventricular function is not immediate but occurs over weeks to months. Chronic ischemia accompanying this lesion results in devitalization (or adaptive response) of the myocardium at a cellular and biochemical level. Devitalized myocardium has been termed hibernating myocardium. Devitalized muscle slowly recovers over the time described once adequate blood flow and oxygen delivery are established.

Several pathologic features may result in mitral valve regurgitation. There may be extensive fibrosis and sometimes calcification in the papillary muscles, leading to dysfunction. Endocardial fibroelastosis may involve the mitral apparatus, with fusion and shortening of chordae tendineae. Also, papillary muscles may be abnormally positioned, leading to mitral regurgitation. ^, Extensive left ventricular fibrosis can produce left ventricular and mitral anular dilation and mitral regurgitation. ^, Reversible left ventricular ischemia must, to some degree, contribute to the mitral valve regurgitation in infants because, in most cases, it decreases to an important extent after surgical treatment and creation of a two-artery coronary system.

Symptoms may be recognized within a week or so of birth. When there are no other anomalies, these are seldom severe enough to warrant referral before age 2 months. Presumably, high postnatal pulmonary artery pressure limits runoff into the pulmonary trunk, so there is less coronary steal, and myocardial dysfunction is gradual in onset rather than sudden. Circumoral pallor and blueness are often present. The cardinal symptom is poor feeding. The baby takes the first 2 to 3 ounces well but then stops; there is breathlessness and sweating, and the baby may draw up the knees, arch the back, and uncommonly, cry or scream. The presumed cause is angina. As a result of the feeding problem, weight gain is poor. Few infants with these symptoms improve spontaneously. Usually, by age 2 to 3 months, there is overt heart failure with persistent tachypnea and tachycardia. The infant, by then, is seriously ill and occasionally moribund.

Clinical signs are difficult to distinguish from those of cardiomyopathy. There may be a nonspecific systolic murmur at the base, or a more definite apical pansystolic murmur caused by mitral regurgitation, and an apical gallop rhythm. A continuous murmur is not audible in infants. A precordial lift is common in association with marked and frequently gross cardiomegaly. Hepatomegaly is also present, and rales are heard throughout the lungs.

In some patients, a rich collateral circulation from the right coronary artery may provide adequate circulation to the left coronary artery system. These patients may have a delayed presentation even beyond the age 20 years. Some adults remain asymptomatic or complain only of fatigue, dyspnea, or palpitations. About half have effort angina. There usually is a nonspecific systolic murmur, sometimes an apical pansystolic murmur from mitral regurgitation, and occasionally a continuous murmur over the upper left sternal edge due to retrograde flow from the coronary artery into the pulmonary trunk. Occasionally, mitral regurgitation dominates the clinical picture, producing heart failure.

The electrocardiogram (ECG) is frequently helpful in diagnosis because it usually shows anterolateral infarction with Q waves and ST-segment elevation in lateral chest leads. Because 20% to 45% of patients do not show abnormal Q waves, the diagnosis should be strongly suspected in cases of abnormal R-wave progression. The resting ECG is virtually always abnormal in patients presenting late with ST-T segment changes or evidence of old anterolateral infarction.

The chest radiograph almost universally shows cardiomegaly. In addition, interstitial pulmonary edema may be evident in infants with heart failure.

Echocardiography in infants shows a dilated, poorly contracting left ventricle (with ejection fraction typically <20%) and reveals the functional status and morphology of the mitral valve. In addition, 2D and pulsed Doppler echocardiography may detect an abnormally large right coronary artery and anomalous connection of the left coronary artery to the pulmonary trunk, with retrograde flow in it ( Fig. 38.1 ). ^, The most important markers visualized on echocardiography include, in order of decreasing sensitivity, flow reversal in the left main coronary artery, collateral coronary flow, dilation of the right coronary artery, abnormal Doppler signal in the pulmonary artery, mitral regurgitation, left ventricular systolic dysfunction, left ventricular fibroelastosis, and visualization of an anomalous coronary connection. Visualization on echocardiography of the left coronary artery arising from the aorta is not a reliable sign to rule out an anomalous pulmonary connection of the left coronary artery, and further imaging should be pursued if there is a suspicion for it otherwise. In many cases, echocardiography alone may be diagnostic enough to proceed with surgical correction, especially in patients who present in extremis and require emergency surgical repair.

Two-dimensional echocardiogram and color-flow Doppler interrogation of anomalous left coronary artery from the pulmonary artery. (A) Apical four-chamber view showing left ventricle (LV) in both diastole and systole. Note markedly dilated LV cavity with severely reduced LV systolic function. (B) Transthoracic echocardiographic image of anomalous connection of left main coronary artery (LMCA) to pulmonary artery. (C) Color Doppler image of view shown in B. Ao, Aorta; Cx, circumflex coronary artery; LAD, left anterior descending coronary artery; PT, pulmonary trunk; S, septal coronary artery.

Advances in computerized tomographic angiography (CTA) imaging and ECG gating have made CTA an essential adjuvant in the diagnosis of coronary artery anomalies ( Fig. 38.2 ). CTA identifies the exact origin and course of the anomalous coronary, the branching of the vessel, the presence of collaterals, and the morphology of the right coronary artery, which is usually dilated. ^,

Computerized tomographic angiography of a 6-year-old girl with a previously undiagnosed connection of anomalous left coronary artery from the pulmonary artery. The image shows a dilated anomalous left coronary artery (arrow) . Ao , Aorta; PT , pulmonary trunk.

(© 2023 Dell Medical School at The University of Texas at Austin, reprinted with permission.)

The role that cardiac magnetic resonance (CMR) plays in the diagnosis of these anomalies is limited, especially due to its lower spatial resolution compared to CTA and the need for sedation in infants. In some patients with late presentation and stable clinical course, CMR may provide valuable information regarding myocardial function and viability, left ventricular dimensions and dynamics, regional wall motion abnormalities, and mitral regurgitation. ^,

Cardiac catheterization and coronary angiography were previously used to provide definitive diagnosis but are now seldom necessary. Their use is limited to cases in which other noninvasive modalities are inconclusive or to help define other associated anomalies not assessed by other means. An aortogram demonstrates connection of the single right coronary artery to the aorta and retrograde filling of the left coronary artery through collaterals, which produces a varying degree of opacification of the pulmonary trunk ( Fig. 38.3 ). A left ventriculogram can be used to assess left ventricular function and degree of mitral regurgitation.

Biplane cineangiographic frames in 3-month-old infant with anomalous left coronary artery from the pulmonary artery. (A-B) In right anterior oblique projection. (C-D) In left anterior oblique projection. In A and C, right coronary artery (RCA) fills directly from aorta, and prominent conal branch collaterals are visible. In B and D, there is delayed retrograde filling of left anterior descending (double arrowheads) and circumflex arteries (single arrow) . Whiff of contrast can be seen in the pulmonary trunk (x) in D.

In infants, myocardial enzymes may be elevated. In patients presenting late, exercise ECG usually shows an abnormal ischemic response. Myocardial viability studies such as stress thallium myocardial imaging, stress echocardiography, stress CMR, and positron emission tomography scans may be used to evaluate myocardial viability, but their use is limited because they are unlikely to change patient management.

The aim of surgical repair is to construct a two-artery coronary system. Direct translocation of the anomalous coronary artery into the aortic root is almost always possible with appropriate mobilization. Smith and colleagues found the distance between the midpoint of the empty left aortic sinus and the posterior aspect of the anomalously connected coronary artery to vary between 2 and 18 mm. The longer distances probably preclude direct implant and may require alternative lengthening procedures.

The operation is best done with cardiopulmonary bypass (CPB) and mild to moderate hypothermia to allow for potentially decreasing bypass flows intermittently due to significant coronary return. After sternotomy, the pericardium is opened without touching the heart because even the slightest trauma can induce ventricular fibrillation. Cannulation is achieved through direct aortic cannulation and either single venous or bicaval cannulation. Immediately before commencing CPB, tourniquets are placed around the left and right pulmonary arteries. The tourniquets are tightened as CPB is initiated to prevent perfusion steal into the pulmonary bed from collateral flow through the anomalous left coronary artery. If present, the patent ductus arteriosus is ligated.

After application of an aortic clamp, cardioplegia is administered directly into the aortic root. Myocardial protection during aortic clamping is particularly important for two reasons: the existing compromised state of the myocardium and the potential for inadequate delivery of cardioplegic solution to the left ventricle. It is important that both pulmonary arteries are appropriately snared to prevent runoff of cardioplegia into the pulmonary bed. A left-sided vent is placed through a purse string in the right upper pulmonary vein or through the atrial septum if the right atrium is opened.

After administering antegrade aortic cardioplegia, the branch pulmonary artery tourniquets are removed. A transverse incision is made in the pulmonary trunk just distal to the commissure of the pulmonary valve. Additional cardioplegia is administered directly into the ostium of the anomalous left coronary artery.

Direct translocation of the anomalous coronary artery is easier when it arises from the posterior right-sided aspect of the pulmonary trunk ( Fig. 38.5 A). The pulmonary trunk is completely transected several millimeters above the level of the anomalous coronary ( Fig. 38.5 B). ^, The incision is arranged so that a sizable button of pulmonary trunk wall around the coronary ostium is excised ( Fig. 38.5 B). The left coronary artery is mobilized with care not to injure the vessel or its branches. An opening is made in the adjacent left posterolateral portion of the aorta ( Fig. 38.5 C). This opening can be performed either as an oval-shaped opening or as a medially based trapdoor to keep an appropriate orientation of the coronary. It is imperative not to injure the aortic valve while creating the opening. Some surgeons create an anterior aortotomy to visualize the aortic valve before creating the coronary translocation opening. The button around the coronary ostium is anastomosed to the aorta with 7-0 monofilament absorbable sutures, the coronary artery explant site is patched, and the pulmonary trunk is reconstructed by end-to-end anastomosis (see Fig. 38.5 C).

Left coronary artery translocation. (A) Favorable position of anomalous left coronary artery ostium for direct translocation. (B) Pulmonary trunk has been transected just above sinutubular junction, revealing anomalous coronary connection. Coronary button in the sinus of Valsalva containing the anomalous coronary has been incised. Of note, the button of sinus tissue around the ostium should be made as large as possible without injuring the pulmonary valve. Also shown by dotted line is position of the aortotomy, placed in optimal position for translocating the coronary. Of note, care should be taken in creating the aortotomy not to injure the aortic valve. If there is concern regarding position of the aortotomy in relation to the aortic valve, a separate ascending aortotomy can be performed to determine the aortotomy site relative to the aortic valve cusps. (C) The coronary artery is mobilized over an appropriate length so that there is no tension as the artery is brought over to the aortotomy site. A running 7-0 monofilament absorbable suture is used to create the coronary to aortic anastomosis. Also shown is the pulmonary trunk end-to-end reconstruction and reconstruction of the coronary explant site using a patch of glutaraldehyde-treated autologous pericardium, pulmonary trunk allograft, or polytetrafluoroethylene.

The remainder of the operation is completed in the usual fashion. Weaning the patient from CPB may require patience, intravenous nitroglycerin, judicious inotropic support, and monitoring of left and right atrial pressures to avoid distention of the heart.

A number of techniques have been described to increase the likelihood of translocation of the anomalous coronary into the aorta for coronary arteries remote from the aorta. The coronary artery can be extended by autologous flaps of aorta or pulmonary trunk. One such technique is shown in Fig. 38.6 . In adult patients with a long distance between the aorta and the left coronary button, an interposition graft using a saphenous vein or a polytetrafluoroethylene (PTFE) tube graft may be used.

Technique for extending coronary artery. (A) Pulmonary trunk is transected above level of pulmonary valve. A sleeve of pulmonary trunk posterior wall is excised along with left coronary orifice. Inset, Partially excised pulmonary trunk wall in continuity with connection of left coronary artery (LCA). (B) Upper and lower edges of this pulmonary flap are sewn together with a 7-0 or 6-0 monofilament suture in order to form a tube-shaped autologous graft 3 to 4 mm in internal diameter in continuity with connection of left coronary. (C) Graft is sutured end to side into left posterior wall of ascending aorta with a 6-0 monofilament suture. Defect in pulmonary trunk is repaired with a fresh autologous pericardial patch. RCA, right coronary artery.

(From Wu Q, Xu Z. An alternative procedure for correction of anomalous origin of left coronary artery from the pulmonary artery. Ann Thorac Surg . 2007;84(6):2132-2133.)

The Takeuchi repair has been used for cases where the distance between the anomalous left coronary artery and the aorta is too long. As surgeons have gained more experience with coronary artery translocation as part of the arterial switch operation (see “ Arterial Switch Operation ” in Chapter 44 ), it has become clear that coronary translocation is possible in virtually all instances. This realization, in addition to the potential complications associated with the Takeuchi repair, has made this technique less relevant, but it remains a useful tool in the surgical armamentarium.

A button of aortic wall about 5 to 6 mm in diameter is excised at a point at which the left wall of the aorta is in contact with the right side of the pulmonary trunk, taking special care to avoid injury to the aortic valve cusps ( Fig. 38.7 A). Directly opposite this, a button is excised from the right wall of the pulmonary trunk ( Fig. 38.7 B [also see A ]). These openings are sewn together with continuous 7-0 polypropylene to create an aortopulmonary window.

Tunnel operation (Takeuchi repair). (A) After instituting cardiopulmonary bypass using techniques to maximize myocardial preservation, the initially small transverse pulmonary arteriotomy, made to confirm the unfavorable position of the anomalous coronary ostium for direct translocation, is extended to develop an anterior pulmonary trunk wall flap. It is based on the right lateral aspect of the pulmonary trunk. Dotted lines indicate (1) positions of buttons on adjacent aortic and pulmonary trunk wall that are to be removed, and (2) extent of incisions used for anterior pulmonary trunk flap. (B) Anterior pulmonary trunk wall flap has been fully developed, and aortopulmonary window anastomosis is created using a running 7-0 monofilament absorbable suture. During creation of the aortopulmonary window, care should be taken to avoid direct injury or distortion of the semilunar valve cusps and commissures. (C) Aortopulmonary window suture line has been completed, and the anterior pulmonary trunk wall flap has been used to create the tunnel connecting aortopulmonary window and remote ostium of anomalous coronary artery. This anastomosis is also performed with a running 7-0 monofilament absorbable suture. Great care should be taken as the suture line approaches the ostium of the coronary artery to avoid distorting the proximal coronary artery. (D) Remaining defect in the anterior wall of the pulmonary trunk is now reconstructed with an appropriately shaped patch of either glutaraldehyde-treated autologous pericardium, pulmonary trunk allograft arterial wall tissue, or polytetrafluoroethylene. A running monofilament nonabsorbable suture is used. Size of patch should be generous to avoid supravalvar pulmonary stenosis.

Using a flap of anterior pulmonary trunk wall hinged on the right, the anterior wall of the tunnel is created, completing the tunnel conveying blood from the aortopulmonary window across the back of the pulmonary trunk to the anomalously connecting left coronary artery ( Fig. 38.7 C [also see B ]). The large defect in the anterior wall of the pulmonary trunk is reconstructed with a patch of pericardium, pulmonary trunk allograft, or PTFE ( Fig. 38.7 D). Occasionally, this operation narrows the immediately supravalvar portion of the pulmonary trunk sufficiently to require a transannular patch.

Treatment by simple ligation of the left coronary artery has been largely abandoned. This is due to the clear benefits of establishing a dual-coronary circulation and the long-term complications associated with ligation. ^,

Most hospital deaths result from acute cardiac failure.

There is an early, rapidly declining hazard phase for death after repair (perioperative mortality) followed by a low constant phase.

Preoperative clinical status is associated with an increased risk of early death after repair. In a large study of 703 patients who underwent repair of anomalous connection of coronary arteries to pulmonary trunk in the Society of Thoracic Surgeons Congenital Heart Surgery Database, the odds of mortality were higher in patients <5 kg in weight, if preoperative shock was present, and if extracorporeal membrane oxygenation support was required ( Table 38.2 ). Similarly, among 907 patients repaired in the European Congenital Heart Surgeons Association Database, hospital mortality was associated with lower weight, smaller body surface area, longer length of CPB, longer postoperative ventilation (intubation) time, and use of postoperative mechanical support.

According to the study by Thomas and colleagues, and contrary to the findings regarding risk factors for early death, repair in infancy appears to portend a lower risk for long-term (postdischarge) death or transplant after repair ( Table 38.3 ). Another major factor associated with late mortality in that study was use of surgical techniques other than coronary reimplant. This finding was also reported by Radman and colleagues in which a composite outcome of reintervention, transplantation, and death was associated with use of the Takeuchi procedure or other atypical repairs (hazard ratio 8, 95% confidence interval 2.1 to 30) and presence of moderate or worse mitral regurgitation on discharge echocardiogram (hazard ratio 3.4, 95% confidence interval 1.2 to 9.1).

Functional status is generally good late-postoperatively. Of 21 patients assessed by Cochrane and colleagues, 18 were in New York Heart Association (NYHA) functional class I and 3 in class II at midterm follow-up. Similarly, Ojala and colleagues reported on 29 patients who underwent coronary reimplant and found 23 patients in NYHA class I and 6 in class II at a median follow-up of 11 years.

Despite important ventricular dysfunction at presentation, left ventricular function and dimensions improve dramatically after surgical repair, but in many patients, the process can be slow, with some patients requiring inotropic support for several months. ^{, , , ,} Cabrera and colleagues reported an improvement in left ventricular ejection fraction in 34 patients from 21%±6% preoperatively to 41%±16% at hospital discharge, and 60%±7% at last follow-up with a median follow-up of 6 years. Naimo and colleagues analyzed serial postoperative echocardiograms for 32 patients after repair and showed that left ventricular function was normal at a median of 9.5 months (range 2.3 to 16 months). Similar findings were reported by Radman and colleagues who found that most of 98 patients with available data at 3 years after discharge had normal left ventricular function. Weigand and colleagues showed normalization of function in all 25 patients that they followed with a median time to normalization of 91 days (range 5 days to 1.2 years).

In addition to preoperative ventricular function, late presentation plays an important role in degree of improvement in function. In a study involving 105 patients, Zhang and colleagues created a classification and regression tree analysis to identify 3 distinct risk groups for early mortality based on preoperative left ventricular ejection fraction and age at repair. They found that improved left ventricular function depended on the risk group, with patients having a preoperative ejection fraction >41.6% having normalization of ventricular function at 4 days, patients having preoperative ejection fraction ≤41.6% and age ≤127 days having normalization of function in 39 days, and those having preoperative ejection fraction >41.6% and age >127 days having normalization of function in 486 days ( Figs. 38.8 and 38.9 ).

Changes in left ventricular function over time after repair of anomalous left coronary artery from the pulmonary artery. Ventricular function decreased transiently after repair and then improved over time (A). When classified by risk groups, patients in group A (preoperative left ventricular function >41.6%) had faster improvement in function than those in group B (preoperative left ventricular function ≤41.6% and age at operation ≤127 days) and group C (preoperative left ventricular function ≤41.6% and age at operation >127 days) (B). LVEF , left ventricular ejection fraction.

(From Zhang W, Hu R, Zhu Y, et al. Surgical outcomes for anomalous left coronary artery from the pulmonary artery: influence of late presentation. J Thorac Cardiovasc Surg . 2020;159(5):1945-1952.e1.)

Left ventricular dimensions also improve over time, with left ventricular end-diastolic dimension normalizing after 2 to 3 years. Left ventricular reverse remodeling, defined as a ≥10% decrease in left ventricular dimensions, has been associated with better outcomes. These findings indicate that in many patients, severe left ventricular dysfunction present preoperatively is due to reversible devitalization of the myocardium, or myocardial hibernation, as opposed to myocardial stunning (see “ Myocardial Cell Stunning ” under Damage from Global Myocardial Ischemia in Chapter 3 ).

Normalization of left ventricular function may not represent normal myocardium. Using speckle-tracking echocardiography and CMR, Castaldi and colleagues analyzed 10 asymptomatic patients with normal ventricular function who had undergone surgical repair 8.7±4.7 years prior. Using strain and strain rates, they found that longitudinal and circumferential functions were reduced in the left coronary artery territory compared to the right and to normal controls. In addition, CMR identified 3 patients with left coronary artery stenosis; they had the lowest longitudinal strain values in left coronary territories, mildly depressed circumferential strain, and normal radial strain. Another study using speckle-tracking on 18 patients a median of 17 years after repair showed that despite normal ventricular function, longitudinal strain and diastolic function were impaired in all cardiac chambers, particularly in the left coronary territory. Similar findings were encountered by Di Salvo and colleagues on 30 patients after repair. Despite normal left ventricular dimensions and ejection fraction, diastolic variables were abnormal, and left ventricular longitudinal strain and torsion were impaired compared to normal patients.

Mitral regurgitation frequently exists at presentation in these patients. In addition to left ventricular dysfunction, mechanisms of regurgitation include anular dilation, anterior or posterior leaflet prolapse, papillary muscle infarction and fibrosis, and mitral clefts.

Whether to perform mitral valve intervention during initial repair in patients with mitral regurgitation remains controversial. It has been long argued that the basis for regurgitation is ischemia and is reversible. Therefore, the mitral valve should not be addressed routinely at initial operation for the anomalous coronary artery. If residual regurgitation is present, it can be addressed once the ventricle has recovered. ^{, ,} Others have advocated mitral repair in selected cases, such as when regurgitation is moderate or severe, or there are structural abnormalities in the mitral valve. ^{, ,} As such, the use of mitral repair as part of the initial operation is variable, ranging from 0% to 50%, ^{, , , , , , ,} with large multi-institutional studies reporting 8% and 16%. ^{, ,}

Improvement in mitral regurgitation over time is not as predictable as improvement in ventricular function (see Fig. 38.9 ). Regardless of the strategy used, it is clear that need for mitral valve intervention in the future is not ignorable. Patients older than age 1 may be at a higher risk of persistent or recurrent important mitral regurgitation in the future.

Qualitative changes in left ventricular function (A) and mitral regurgitation (B) over time in 98 patients after repair of anomalous left coronary artery from pulmonary artery.

(From Radman M, Mastropietro CW, Costello JM, et al. Intermediate outcomes after repair of anomalous left coronary artery from the pulmonary artery. Ann Thorac Surg . 2021;112(4):1307-1315.)

In a series by Naimo and colleagues involving 42 patients, concomitant repair was undertaken in 9 patients, 5 with severe regurgitation and 4 with moderate. Freedom from late mitral valve intervention at 5 and 10 years in patients that did not undergo repair was 86%±6% (95% confidence interval 71% to 94%). Of the 11 patients with severe regurgitation, 5 (45%) underwent repair at the time of initial anomalous coronary artery repair, 3 underwent intervention later on, and the remaining 3 had mild regurgitation at last follow-up. Zhang and colleagues analyzed 101 patients who underwent anomalous coronary artery repair in the setting of more than mild mitral regurgitation; 66 (65%) underwent concomitant mitral intervention. In their series, cumulative improvement in mitral regurgitation (to ≤mild regurgitation) was 34% (95% confidence interval 19% to 50%) among those who underwent mitral intervention compared to 59% (95% confidence interval 41% to 73%) among those who did not. In patients who underwent mitral intervention, lower grade of mitral regurgitation on postoperative day 1 was the only independent predictor of long-term mitral regurgitation improvement (hazard ratio 0.08, 95% confidence interval 0.018 to 0.366). In contrast, in patients who did not undergo intervention, only a preoperative lower mitral valve anulus diameter z-score was associated with long-term mitral regurgitation improvement (hazard ratio 0.48, 95% confidence interval 0.232 to 0.993). In the multi-institutional study by Thomas and colleagues, 18 (8%) patients underwent mitral valve intervention at the time of repair, with no perioperative deaths. In the cohort of patients with moderate or severe mitral regurgitation, undergoing a mitral valve operation was associated with a 28% unadjusted risk reduction in perioperative mortality compared to those that did not undergo intervention (relative survival ratio 1.28, P =.033).

Based on these reports, one can conclude that (1) mitral regurgitation is common on presentation, (2) it tends to improve with time but improvement is unpredictable, (3) mitral valve intervention during initial repair appears safe, (4) mitral intervention is generally not justified for patients with less than severe regurgitation, and (5) some patients with severe mitral regurgitation may benefit from initial repair, although which particular patients remains unclear.

Diagnosis in adults is unusual and poses additional challenges. Most patients are symptomatic, presenting with chest pain, palpitations, and symptoms of heart failure. The majority have evidence of ischemia on functional testing. ^, In adults, direct implant of the anomalous coronary artery is challenging due to friability of the vessels and loss of elasticity. If tension-free translocation is not possible, placing an interposition graft or performing coronary artery bypass grafting with ligation of the proximal artery may be necessary.

Yau and colleagues performed a comprehensive literature search of all adult cases of anomalous connection of left coronary artery to pulmonary trunk reported in the literature. They found 151 cases with an average age of 41 years, the oldest age 83. Only 14% were asymptomatic; 17% presented with syncope, arrhythmias, or sudden cardiac death, and 66% presented with other symptoms. The majority had functional tests indicative of ischemia. Among the 119 patients who underwent surgical intervention, 79% had a dual-coronary circulation established. The remainder had simple ligation of the anomalous coronary artery. Surgical mortality was reported to be 1% to 4%.

An anomaly rarer than anomalous connection of left coronary artery to pulmonary trunk is anomalous connection of the right coronary artery to the pulmonary trunk. The common name for this defect is anomalous right coronary artery from the pulmonary artery (ARCAPA).

A systematic review by Guenther and colleagues in 2020 identified 223 cases in the literature. Undoubtedly, this lesion is underdiagnosed because of its relatively benign nature compared with anomalous left coronary artery. Many patients are asymptomatic; the diagnosis is most commonly made during workup for a murmur. It is occasionally associated with symptoms in an older child or adult or sudden death. There is a bimodal age distribution in symptomatic patients with a peak during infancy and another between ages 40 and 60 years. Treatment is similar to anomalous left coronary artery to pulmonary trunk, with the majority of patients undergoing coronary reimplantation to the aorta.

Anomalous connection of circumflex and left anterior descending coronary artery to pulmonary trunk are also less lethal than an anomalous left coronary artery, although there have been cases presenting with sudden cardiac arrest. Both are also rarer than anomalous connection of right coronary artery to the pulmonary trunk. Indications for surgery and technique of operation are similar to those for anomalous connection of the right coronary artery. Operation is generally indicated at the time of diagnosis for all these variations.

Rarely, all coronary blood flow originates from the pulmonary trunk, either with a single ostium and trunk from which all branches emerge or from two ostia close together, giving rise to left and right coronary systems. ^, In less than half the cases reported, this has been an isolated anomaly. In such cases, symptoms appear within a few days of birth, and death follows within 2 weeks. A systematic review identified 57 cases in the literature with 45% of cases diagnosed at autopsy. Surgical repair was performed in 22 (46%) with use of aortic translocation in 14 and Takeuchi repair in 7. Due to the high risk of mortality with this lesion, surgical repair should be instituted promptly after diagnosis.

In the normal heart, the left coronary artery connects to the left “facing” sinus (the leftward posterior sinus facing the pulmonary trunk), and the right coronary artery connects to the right anterior facing sinus (the anterior sinus facing the pulmonary trunk). A separate connection of a conal or accessory branch is a normal variation. The normal ostia are located in the middle of the sinus and below the level of the sinutubular junction.

Mery and colleagues have described a topography nomenclature map to facilitate description of the location of connections of the coronary arteries ( Fig. 38.10 ). This map is consistent with the modified Leiden classification commonly used to describe connections of the coronary arteries in the setting of transposition of the great arteries (see Chapter 44 ). The topography map assigns a number to each sinus (1 for the right-facing sinus, 2 for the left-facing sinus, and 3 for the nonfacing sinus). It divides each sinus into a, b, or c, depending on proximity to the commissures. Commissural origins are denoted as X, Y, or Z. Height of the coronary ostium is designated using Roman numerals: I for central connection to the sinus, II for connection to the sinus above the level of the free edge of the open cusps but below the sinutubular junction, III for connection to the sinutubular junction, and IV for connection above the sinutubular junction (ascending aorta). Based on this topographic nomenclature, the normal left coronary artery connects to 2b-I or 2b-II, and the normal right coronary artery connects to 1b-I or 1b-II. This system allows for uniform description and communication among surgeons, radiologists, and cardiologists.

Coronary topography map used to define the location of origin of coronary arteries. The map includes a circumferential location reference and a height reference. Both descriptors should be listed separated by a hyphen. LN , left/nonfacing commsissure; LR , left/right commissure; RN , right/nonfacing commissure.

(© 2023 Carlos Mery at The University of Texas at Austin and Ascension (Dell Children’s), licensed under Creative Commons Attribution-Noncommercial-ShareAlike 4.0 International [CC BY-NC-SA 4.0].)

There is wide variability of connection and course of the coronary arteries in this anomaly. Most anomalous coronaries connect to the opposite sinus of Valsalva just above the level of the intercoronary commissure of the aortic valve. This corresponds to connection 1c-II or 1c-III for the anomalous left coronary artery and 2a-II or 2a-III for the anomalous right coronary artery. Sometimes, the anomalous artery can originate inferior to the level of the commissure (level I) or higher on the ascending aorta (level IV).

There is also wide variability in the coronary ostia ( Fig. 38.11 ). Although the anomalous coronary artery tends to connect to an ostium separate from (Type 1) or adjacent to (Type 2) the normal opposite coronary artery, it can also originate from a single ostium that bifurcates within the wall (Type 3) or a single coronary artery trunk that bifurcates within the mediastinum (Type 4).

Types of relationship between coronary ostia arising from the same sinus.

(© 2024 Carlos Mery at The University of Texas at Austin and Ascension (Dell Children’s), licensed under Creative Commons Attribution-Noncommercial-ShareAlike 4.0 International [CC BY-NC-SA 4.0].)

The normal coronary arteries connect to round ostia at nearly orthogonal angles to the aortic wall. The size of the ostia is equal to or larger than the diameter of the corresponding coronary artery. As anomalous coronary arteries connect at tangential angles, their ostia are acutely angulated and abnormal, and at risk for compression. The ostium of the anomalous coronary, therefore, tends to be either oval (with the transverse diameter equal to 50% to 90% of the longitudinal diameter) or slit-like (transverse diameter <50% of the longitudinal diameter). Using virtual angioscopy from CMR studies in 27 patients, Harris and colleagues found that all anomalous coronaries had ostia with a high ellipticity index (ratio of vertical to horizontal diameter) of 2.4 to 2.5±0.5 compared to normal 1.1±0.1.

The anomalous coronary artery can take different courses to its normal distribution area– prepulmonic, interarterial, subpulmonic, retroaortic, and retrocardiac. An anomalous coronary artery with an interarterial segment is the lesion mostly associated with increased risk of sudden cardiac death. It tends to have a variable length of intramurality in which the vessel is within the wall of the aorta before exiting into the mediastinum. It is believed that intramurality plays an important role in pathophysiology of sudden cardiac death. Using intravascular ultrasound (IVUS), Angelini and colleagues demonstrated that the proximal intramural course of the anomalous coronary can be importantly compressed, which worsens during systole and even further during simulated exercise. The intramural segment seems to play a more important role in ischemia than the actual location of connection of the coronary artery.

Histologically, the intramural segment of the anomalous coronary shares a common media with the aorta. Its wall is mainly composed of elastic fibers instead of smooth muscle as is the case for epicardial coronary arteries.

A morphological structure that is underappreciated in AAOCA, but that likely plays an important role in pathophysiology of ischemia and sudden cardiac death, is the intercoronary pillar. The intercoronary pillar is a thickening of aortic tissue that travels cranially from the level of the intercoronary commissure up to the sinutubular junction and can be quite thick in some individuals. The anomalous coronary can be subject to important compression as it courses behind this thickening of tissue. ^,

In some instances, an anomalous left coronary artery or left anterior descending artery connecting to the right coronary artery or right sinus of Valsalva will have a transseptal course rather than an interarterial course. In these cases, the anomalous artery dives deep into the ventricular septum and has an intramyocardial course within the posterior aspect of the right ventricular outflow tract below the level of the pulmonary valve prior to exiting epicardially on the other side of the outflow tract. The degree of compression of the intramyocardial segment of transseptal coronary arteries and their clinical significance are variable.

Anomalous coronaries can coexist with the presence of other intramyocardial segments (myocardial bridges), especially involving the left anterior descending artery. ^, Myocardial bridges are commonly found in asymptomatic individuals, and their clinical relevance is variable (see text that follows). Assessing the relative importance of myocardial bridges and other morphological features in these patients is critical to determining optimal management.

Right or left coronary dominance is determined by which coronary system supplies the posterior descending artery. Coronary dominance seems to be relevant in determining the clinical importance of coronary artery anomalies. ^,

Echocardiography is the first imaging modality in most patients. It can usually define the origin and course of the anomalous coronary artery, and sometimes reveal whether there are one or two ostia and whether there is an intramural course ( Fig. 38.12 ). However, it is generally not sufficiently accurate to identify more detailed anatomic features such as intramurality and acute ostial angulation. Therefore, further anatomic delineation with cross-sectional imaging, such as CTA or CMR, is recommended.

Transesophageal echocardiographic (TEE) image of anomalous connection of left main coronary artery to right aortic sinus, with intramural course. Small arrows identify aortic valve commissures. Ao, Aorta; LA, left atrium; IM LAD, intramural left coronary artery; RCA, right coronary artery.

Due to its high spatial resolution, CTA has become the mainstay imaging modality for diagnosis and characterization of this anomaly ( Fig. 38.13 ). ^{, ,} Imaging can usually be performed without sedation or beta-blockade, but ECG gating is important to achieve optimal images. Several studies have shown relatively good correlation between CTA and surgical findings. ^, CTA can reliably identify type of anomalous connection, location of connection of the anomalous coronary, presence of interarterial and intramural segments, and morphology of the ostium. Length of intramurality can be assessed by a combination of variables, including shape or eccentricity of the coronary artery (intramural coronary segments are oval instead of round), presence of mediastinal fat between the coronary artery and aorta, and distance between aortic lumen and lumen of the coronary artery (shorter distances tend to correlate with intramural segments). ^{, ,} Length of intramurality tends to be slightly overestimated by CTA compared to surgical measurement. ^, Virtual endoluminal reconstruction views have also been useful in determining the location of connection and the ostial morphology of the anomalous coronary arteries. The morphologic variables that should be assessed and reported on CTA include:

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  Type of anomalous coronary

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  Ostial location

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  Coronary dominance

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  Relationship between the different coronary ostia

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  Ostial morphology

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  Presence and length of intramurality

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  Presence and length of an interarterial segment

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  Presence of an intramyocardial course (transseptal course and myocardial bridges)

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  Course behind a thickened intercoronary pillar

Volume-rendered images from cardiac gated computed tomography angiogram (CTA) demonstrating an intramural course of the right coronary artery. (A) Image from a 13-year-old boy showing right coronary artery (arrow) and left main coronary artery (arrowhead), both connected to left coronary sinus at the aortic root. Right coronary artery has an interarterial course. (B) Short-axis image at aortic root of an 8-year-old boy showing a right coronary artery connected to left coronary sinus. Interarterial portion of right coronary artery is separated from aortic root by a thin wall (arrowheads) , suggesting an intramural coronary artery. Also, right coronary ostium is small and the intramural segment narrowed.

CMR has been used in some series to diagnose and characterize anatomy. However, its lower spatial resolution compared to CTA limits its ability to define clearly all necessary anatomic details. ^, Therefore, CTA as the anatomic imaging modality of choice is recommended. Stress CMR is helpful as a functional imaging modality (see text that follows).

Despite use of cross-sectional imaging for diagnosis of this coronary anomaly, coronary angiography continues to be helpful in certain circumstances. IVUS can assess the degree of compression or stenosis of the ostium and intramural segment, especially while simulating exercise with a combination of saline, atropine, and dobutamine. ^{, ,} In addition, measurement of the pressure gradient between the aorta and the distal coronary artery using fractional flow reserve (FFR), with and without provocative testing, assesses the significance of compression of the anomalous coronary. ^, No clear guidelines, however, currently exist regarding specific FFR thresholds. These techniques have been used in children and adolescents, especially those with intramyocardial vessels, to assess importance of that segment. Furthermore, atherosclerotic coronary artery disease has been reported in up to 60% of patients with this anomaly. It is therefore recommended that every adult being considered for surgical intervention undergo cardiac catheterization preoperatively. Coronary angiography should also be considered in patients with intramyocardial segments (i.e., transseptal course or myocardial bridge) and those in which more invasive testing can help with risk stratification.

Exercise stress testing (EST) is widely used to assess ischemia in this anomaly, but its utility is controversial. Basso and colleagues reported on 27 athletes who suffered sudden cardiac death in Italy and 6 of them had had a negative EST within 6 to 18 months before their death. Qasim and colleagues found poor correlation between EST and stress CMR in 155 patients with this anomaly. The addition of cardiopulmonary exercise testing (CPET) increased sensitivity of the study at the expense of specificity. Based on these reports, EST should not be used as the only functional testing modality, especially if negative. Additional functional modalities should be used to identify presence of ischemia.

Stress CMR assesses myocardial perfusion, wall motion, and myocardial viability. True exercise stress CMR may be performed using a treadmill next to the CMR scanner or an in-scanner supine ergometer. These techniques, however, are limited by the need for specialized equipment, the difficulty in using them in children and adolescents, motion artifacts from heavy breathing, inability to reach maximum heart rate, and, for the treadmill CMR, changes in heart rate as the patient is moved from the treadmill to the scanner. Due to these limitations, stress CMR has been mainly performed using pharmacologic agents to simulate exercise. Dobutamine has been found to simulate exercise well because it increases heart rate and myocardial contractility while decreasing systemic vascular resistance and increasing coronary vasodilation. Dobutamine-stress CMR is not only safe in pediatric and adult patients with this coronary anomaly but has been found to correlate with invasive measurements of coronary perfusion in these patients.

Dobutamine-stress echocardiography has been used in these patients and may become a potentially helpful functional imaging modality. However, its appropriate use requires significant expertise.

Functional imaging can also be performed using nuclear perfusion imaging. Stress-rest 99m Technetium-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) has been used to assess ischemia in patients with this coronary anomaly. ^, Recent studies have combined CTA with SPECT to create hybrid images that contain data on coronary anatomy detail and perfusion. ^, Other groups have used positron-emission tomography with computerized tomography (PET-CT) to define the coronary anatomy and presence of ischemia. ^, PET-CT can be performed either using exercise or with pharmacologic agents such as dobutamine and has been found to have superior spatial resolution and less susceptibility to artifact than SPECT. These modalities will likely play an increasing role in defining ischemia in patients with this anomaly in the future.