The American Heart Association (AHA) and the European Society of Cardiology (ESC) have proposed classifications for pulmonary embolism severity. Acute massive (AHA) or high-risk (ESC) pulmonary embolism is the sudden entrapment of dislodged thrombus in the pulmonary arteries, usually from deep veins of the legs, pelvis, or arms. It is life-threatening and can result in right heart failure, low cardiac output, and sudden death.

The first pulmonary embolectomy was performed by Trendelenburg in 1908, but long-term survival using his technique was not achieved until 1924. ^, It is prophetic and of great significance that Dr. John Gibbon, who in 1953 performed the first successful operation on a patient totally supported by cardiopulmonary bypass (CPB) using a pump-oxygenator, envisioned use of CPB to treat massive pulmonary embolism.

The first successful pulmonary embolectomies performed using CPB were reported by Cooley and colleagues in l961 and Sharp in 1962. ^, The discovery of heparin by McLean and the demonstration of its clinical utility by Murray and colleagues reported in 1937 was a critical parallel advance for the management of this condition.

Detached venous thrombi pass through the right heart and enter the pulmonary arteries as a single thrombus or as fragmented smaller thrombi. The majority of thrombi lodge in the lower lobes, slightly more often in the right than left lung. Pulmonary artery pressure rises if greater than 30% to 50% of the total cross-sectional area of the pulmonary vasculature is occluded. Shortly after reaching the lungs, emboli become coated with a layer of platelets and thrombin. Pulmonary arterial obstruction and release of vasoactive agents such as serotonin, adenosine diphosphate, platelet-derived growth factor, and thromboxane by platelets elevate pulmonary vascular resistance (Rp). Alveolar dead space increases because of redistribution of blood flow and impairs gas exchange. As right ventricular (RV) afterload increases, RV pressure rises. This may result in RV dilation, myocardial ischemia, and dysfunction. Increased Rp reduces RV stroke volume and left ventricular filling (preload). Reduction in preload and coronary blood flow associated with systemic hypotension markedly reduces left ventricular stroke volume. If a patent foramen ovale or atrial septal defect is present, right-to-left shunting of blood and severe hypoxemia may occur, as may paradoxical embolization.

In the United States, approximately 100,000 patients are diagnosed with acute pulmonary embolism each year, resulting in thousands of recognized deaths. ^, Many additional deaths occur yearly because of undiagnosed massive pulmonary embolus mistaken for acute myocardial infarction or ventricular arrhythmia. In the International Cooperative Pulmonary Embolism Registry of 2454 consecutive patients presenting with acute pulmonary embolism from 7 countries, 4.2% had massive embolization.

Untreated massive pulmonary artery embolism, accompanied by hypoxemia and hemodynamic instability, is nearly always fatal. Most deaths occur before effective treatment can be initiated. It is estimated that mortality for obstruction of more than 50% of the pulmonary vasculature approaches 50% and increases to 70% if the patient requires vasopressor therapy. If clinical deterioration continues, mortality approaches 100%.

Postoperative circulatory support with VA-ECMO can benefit patients with persisting severe RV failure after embolectomy.

Anticoagulation with warfarin is recommended for at least 6 months if there is no contraindication. If not already in place, an inferior vena caval filter should be inserted into patients for whom anticoagulant therapy is contraindicated.

There is reasonable evidence that surgical embolectomy results are improving in the contemporary era. Kilic and colleagues, by using International Classification of Diseases-9 (ICD-9) codes from the Nationwide Inpatient Sample, identified 2709 patients undergoing surgical embolectomy for pulmonary embolism between 1999 and 2008 (although unable to discriminate massive pulmonary embolism from other degrees of severity). The inpatient mortality was 27.2%. A similar analysis using the same data source (and the same limitations) was performed by Alqahtani and colleagues. They found an inpatient surgical embolectomy mortality between 2003 and 2009 and 2009 and 2014 of 23.1% and 14%, respectively. Although the reported operative mortality rate is still quite variable, some series have maintained improved outcomes for surgical embolectomy for massive pulmonary embolism. A consistent finding in many of these reports is that the operative mortality is substantially greater in patients who are in cardiogenic shock, who have sustained a cardiac arrest, or who are undergoing cardiopulmonary resuscitation on the way to the operating room. The combined use of VA-ECMO and pulmonary embolectomy (surgical or catheter-based) appears to be a strategy that can rescue many of these critically ill patients.

Indications for pulmonary embolectomy for massive pulmonary embolism should not be considered categorical because the management decision for an individual patient is modulated by programmatic experience and technical resources (surgical vs. catheter-based intervention), the advent of multidisciplinary decision-making using Pulmonary Embolism Response Teams (PERTs), and the lack of clarity regarding the procedural approach with superior clinical outcomes.

However, surgical pulmonary embolectomy should be considered in patients with a massive pulmonary embolus under the following circumstances—contraindications to thrombolytic therapy (such as recent brain or spinal surgery, previous intracranial hemorrhage, structural intracranial disease, ischemic stroke within 3 months, bleeding diathesis, recent head trauma with skull fracture, or brain injury); failed thrombolytic or catheter-based intervention; free-floating thrombus in transit through the right heart ( Fig. 25.3 ); and thrombus in transit through a patent foramen ovale ( Fig. 25.4 ). Although failed thrombolysis is an indication for pulmonary embolectomy, intractable bleeding may be encountered. Massive pulmonary embolism in pregnancy is a rare but catastrophic event, but surgical embolectomy may be the preferred strategy, in part due to the high incidence of uterine bleeding with thrombolysis.

TEE demonstrating free floating thrombi in-transit through the right atrium and right ventricle.

(Courtesy of Dr. Mustafa Ahmed, UAB.)

TEE demonstrating thrombus in-transit through a patent foramen ovale.

(Courtesy of Dr. Mustafa Ahmed, UAB.)

In massive pulmonary embolism, the initial therapy is anticoagulation with unfractionated heparin. However, this is invariably insufficient therapy and additional strategies are required, including systemic thrombolysis, catheter-directed therapies, or surgical embolectomy.

Chronic pulmonary thromboembolic disease is entrapment of thrombi in pulmonary arteries from a single episode or repeated embolic episodes that subsequently organize, or thrombi that develop in situ in the pulmonary arteries into firm, fibrous tissue that becomes incorporated into the vessel wall. These processes result in variable degrees of pulmonary artery obstruction and consequent pulmonary hypertension when obstruction becomes severe. ^, Chronic pulmonary TED is estimated to develop in 1% to 5% of all cases of acute pulmonary embolism. ^,

Chronic pulmonary embolism was suspected by Hart in 1916 and by Molle in 1920. Still, it was not until 1928 that Ljungdahl described two symptomatic patients with chronic obstruction of the pulmonary arteries who ultimately died of right heart failure. The first successful embolectomies for recurrent pulmonary embolism were reported by Allison and colleagues in 1958 and by Snyder and colleagues in 1963. ^, The technique was refined by Cabrol and colleagues, who used a lateral thoracotomy approach to obtain access to distal branches of the pulmonary arteries. Subsequently, several small series of patients were reported by Sabiston, Daily, and Dor and their colleagues, who used the lateral thoracotomy approach or CPB with a midline sternotomy. In 1980, Daily and colleagues reported use of hypothermic circulatory arrest in combination with CPB. This technique was used to eliminate severe back bleeding from the collateral circulation and improve visualization of the pulmonary arteries during endarterectomy.

The chronic thromboembolic process typically involves the proximal pulmonary arteries from trunk to sublobar levels characterized by fibrous tails, blind pouches, webs, and bands ( Fig. 25.5 ). The distal arterial vasculature remains patent. This forms the basis for surgical treatment of this disorder. The disease can result from a single embolic episode with nonresolution of large thromboemboli or from repeated embolic episodes. ^, Pulmonary arteries remaining unobstructed are chronically exposed to high flow and, eventually, high pressure. As a result, the proximal patent pulmonary arteries become greatly enlarged, and the distal arterial vasculature develops characteristic changes of pulmonary hypertension. Plexiform lesions in adult lungs diagnostic of primary pulmonary hypertension have been observed in chronic thromboembolic pulmonary hypertension (CTEPH).

Pulmonary endarterectomy specimen demonstrating blind pouch, fibrous webs and tails, and insitu thrombus.

The occlusive process is commonly discrete and central. When the thrombi become fibrotic and endothelialized, they no longer respond to thrombolytic or anticoagulant therapy. Recanalization occurs through thromboembolic lesions and has important implications for imaging. Occasionally, fresh thrombus is attached to the organized thrombus. Microscopically, thrombotic material demonstrates well-organized fibrous tissue, penetrating blood vessels, elastic fibers, and absence of endothelial cells. There is intimal and medial hyperplasia. Infarction of lung tissue infrequently occurs. Bronchopulmonary collaterals may be extensive ( Fig. 25.6 ).

Selective injection of conjoint origin of right and left bronchial arteries demonstrating extensive collateral circulation in the airway wall and parenchyma.

(Courtesy of Dr. Tim Joseph, The Alfred.)

Patients with CTEPH may remain asymptomatic for months or years. Hemodynamic progression may result from recurrent thromboembolism or in situ pulmonary artery thrombosis. Without intervention, survival is low and proportional to the degree of pulmonary hypertension at time of diagnosis. ^, In the study of Riedel and colleagues, survival at 5 years was 30% among patients with a mean pulmonary artery pressure exceeding 40 mmHg at time of diagnosis, and only 10% among those with a mean pressure above 50 mmHg. In the study of Lewczuk and colleagues, a mean pulmonary artery pressure of 30 mmHg was the threshold for a poor prognosis. Among the 13 patients evaluated by Riedel and colleagues, 9 died a mean of 2.8 years after diagnosis of right heart failure; 7 of the 13 had evidence of recurrent embolization.

It is appropriate to be mindful of this historic natural history data of untreated CTEPH that illustrate the potential lethality of CTEPH. However, it is also important to be aware of the contemporary data regarding the outcome of inoperable CTEPH, which is not directly analogous to the older natural history data but nonetheless important in therapeutic decision-making. Approximately 40% of patients are deemed unsuitable for a PEA because of surgically inaccessible distal disease, preponderance of microvascular disease, or comorbidity. ^, However, a study by Taniguchi and colleagues demonstrated that a cohort of patients with CTEPH not undergoing PEA (93% due to technically inoperable disease) in the era from 2013 to 2016 had 3-year survival of 85%, the use of BPA convincingly contributing to this survival and to a lesser extent, pulmonary vasodilator drugs as either monotherapy or combination therapy (endothelin-receptor antagonists, prostanoids, drugs targeting the nitric oxide pathway, and soluble guanylate cyclase stimulators). This survival is comparable to the report from Inami and colleagues who achieved a 95.5% 5-year survival in patients with CTEPH using BPA.

Postoperative care is conducted as described in Chapter 5 . Mechanical ventilation is used with an F io ₂ sufficient to maintain Sa o ₂ greater than 95%. Pa co ₂ is maintained at or below 35 mmHg. Reperfusion pulmonary edema is occasionally encountered postoperatively and is an important problem in approximately 10% of patients. Lung injury usually develops within the first 48 hours and is characterized by hypoxemia and radiographic infiltrates in the areas that have been endarterectomized and reperfused. Treatment is generally supportive, using the lowest F io ₂ to maintain Sa o ₂ greater than 90% and positive end-expiratory pressures of 5 to 10 cm. Aggressive diuresis is often necessary to remove fluid and reduce the incidence of pulmonary edema. Reperfusion pulmonary edema has been demonstrated to be neutrophil-mediated, and treatment with agents that block selectin-mediated adhesion of leukocytes to the endothelium has reduced the prevalence of this complication.

Hypoxemia is relatively common after PEA due to the shunt created by the ventilation/perfusion (V/Q) mismatch through the endarterectomized lobes. Some patients will require supplemental oxygen, but this requirement disappears by about 3 to 4 weeks postoperatively. A heparin infusion may be commenced when the chest tube output is less than 25 mL/hour for 2 consecutive hours, and warfarin is given on the first postoperative day.

In the contemporary era, the operative mortality of PEA in experienced centers is less than 5%. The short-term benefits of PEA with respect to improvement in symptoms, hemodynamics, and exercise capacity have been well established. The longer-term benefits have been investigated in comprehensive outcomes studies such as that from the United Kingdom National Cohort, which reported on the outcomes (survival and residual pulmonary hypertension) of 880 consecutive patients undergoing PEA for CTEPH. The actuarial survival following PEA at 1 and 10 years was 86% and 72%, respectively ( Fig. 25.16 ). For patients surviving the postoperative period, causes of death were codified as: (1) CTEPH direct (such as RV failure), (2) CTEPH related (such as anticoagulation complication), and (3) unrelated (such as malignancy). The cumulative incidence of causes of death are also depicted in Fig. 25.16 .

Survival and classification of causes of death for PEA cohort. (A) Kaplan–Meier curve showing cohort survival. (B) Cumulative incidence of postoperative deaths improves with center experience. PEA number is consecutive PEA operations including indications other than CTEPH. N indicates number of PEA operations for CTEPH. (C) Kaplan–Meier curve comparing survival of first versus second half of cohort. (D) Cumulative incidence of causes of death (see Methods for classification) for patients surviving postoperative period. The number of patients at risk over follow-up as shown bottom of C. CTEPH indicates chronic thromboembolic pulmonary hypertension; and PEA, pulmonary endarterectomy.

(From Cannon JE, Su L, Kiely DG, et al. Dynamic risk stratification of patient long-term outcome after pulmonary endarterectomy: results from the United Kingdom National Cohort. Circulation . 2016;133(18):1761-1771, with permission.)

Residual pulmonary hypertension after PEA is common. In the study by Cannon and colleague,s 51% of patients had a mean pulmonary artery pressure of greater than or equal to 25 mmHg when measured at 3 to 6 months post-PEA. The cumulative incidence of initiation of pulmonary vasodilator therapy post-PEA is depicted in Fig. 25.16 . Based on their data, this group proposes that a mean pulmonary artery pressure greater than or equal to 30 mmHg is the threshold for significant post-PEA residual pulmonary hypertension requiring pulmonary vasodilator therapy. The right heart catheterization to determine the need to initiate pulmonary vasodilator therapy should be delayed until 3 to 6 months postoperatively.

It is important that the assessment of operability occurs in an experienced multidisciplinary center for the management of CTEPH, ^{, , ,} and the experience of the team is a major determinant of the outcome for an individual patient. The indications ^, for PEA are based on the following considerations:

• •

  PEA should be considered in patients who have hemodynamic or ventilatory impairment at rest or exercise

• •

  There should be concordance between the severity of the pulmonary hypertension and the extent of the TED and obstruction

• •

  The extent and level of thromboembolic obstruction should be based on high-quality imaging

• •

  The severity of pulmonary hypertension—patients with a significantly elevated pulmonary vascular resistance, >1500 dynes per second/cm ^–5 , traditionally thought to have a prohibitive operative mortality may still have substantial benefit from PEA. This degree of pulmonary vascular resistance is no longer considered a contraindication to PEA

• •

  Patients with chronic thromboembolic disease (CTED)–pulmonary artery pressure is normal at rest but becomes elevated on exercise. These patients should be considered for PEA as they may be quite symptomatic

• •

  Presence of comorbidity

• •

  Presence of coexisting cardiac disease

• •

  Realistic patient expectations regarding the benefit/risk assessment

An important absolute contraindication to PEA is the presence of severe underlying obstructive or restrictive lung disease.

A true pulmonary artery aneurysm is a focal dilation of all three layers of the pulmonary artery. A pseudoaneurysm lacks all three layers of the arterial wall. This section discusses only aneurysms of the pulmonary trunk and branch pulmonary arteries (proximal pulmonary artery aneurysms) that are amenable to surgical treatment.

The pulmonary artery size that qualifies as aneurysmal has not been clearly defined. The mean diameter of the main pulmonary artery in healthy adults is 25 mm ±3 mm, with an upper limit in males of 29 mm and females 27 mm. The most common definition of a pulmonary artery aneurysm is dilation greater than 1.5 times the upper limit of normal.

The first description of a pulmonary artery aneurysm was by Bristowe in 1860. He reported an arteriosclerotic fusiform aneurysm of the pulmonary artery observed at autopsy. In a review of 109,571 autopsies by Deterling and Clagett in 1947, only 8 proximal pulmonary artery aneurysms were identified. The first successful repair of an aneurysm of the pulmonary trunk was reported by Williams and colleagues in 1971. It was resected and replaced with a woven polyester graft. Aneurysmorrhaphy and patch repair were subsequently used as an alternative method of treatment. ^,

The morphologic classification of pulmonary artery aneurysms is outlined in Box 25.1 . From an historical standpoint, Eisenmenger syndrome has been the most common cause of a pulmonary artery aneurysm. Congenital cardiac abnormalities can be associated with pulmonary artery aneurysms. ^{, ,} The most common of these are abnormalities of the pulmonary valve (e.g., pulmonary valve stenosis). Pulmonary artery aneurysms also occur as part the Noonan syndrome ^, or connective tissue abnormalities such as Marfan syndrome, such as Loeys-Dietz syndrome, Ehlers-Danlos syndrome, and medial degeneration. ^,

Pulmonary arterial hypertension is an important acquired cause of a pulmonary artery aneurysm. Other acquired causes include vasculitis and autoimmune conditions such as Behcet syndrome and Hughes-Stovin syndrome. Iatrogenic and traumatic mechanisms usually result in pseudoaneurysms. Postinfectious causes can result in true aneurysms and pseudoaneurysms; historically, untreated syphilis and tuberculosis were leading causes. ^, Bacterial infections (infective endocarditis, pneumonia, lung abscess, and staphylococcal bacteremia, often associated with intravenous drug abuse); fungal infections (candida, mucormycosis, and aspergillus); and parasitic infections such as schistosomiasis are all causes of true aneurysms and pseudoaneurysms. ^,

Patients with proximal pulmonary artery aneurysms may present with cough, hemoptysis, chest pain, and dyspnea, although many are asymptomatic. Symptoms, if present, may be related to associated cardiac or pulmonary conditions. Compression of the left main coronary artery can result in myocardial ischemia. There are no characteristic physical findings. The chest radiograph may be normal, but if the aneurysm is large, it demonstrates a prominence along the left heart border. CT scan will define the pulmonary artery aneurysm ( Fig. 25.17 ).

Computed tomographic study in a patient with severe pulmonary arterial hypertension, previous Mustard repair of transposition and a giant pulmonary artery aneurysm. Note the pulmonary artery arising from the left ventricle.

(From Doi A, Gajera J, Niewodowski D, et al. Surgical management of giant pulmonary artery aneurysms in patients with severe pulmonary arterial hypertension. J Card Surg . 2022;37(4):1019-1025, with permission.)

Because pulmonary artery aneurysms are rare and coexisting conditions are common, natural history remains largely unknown. It is known, however, that rupture and dissection of such aneurysms occur. ^, Death following rupture or dissection is common and often sudden.

Usual preparations for establishing CPB are made (see “ Preparation for Cardiopulmonary Bypass ” in Section III of Chapter 2 ). After inserting appropriate monitoring devices and placing ECG electrodes, a median sternotomy is made. Cannulae are inserted into the ascending aorta and both venae cavae. Venae cavae are encircled with tapes, CPB is established, and a venting catheter is inserted into the left atrium through a purse-string suture in the right superior pulmonary vein. The procedure can be performed with the heart beating and mild (34°C) hypothermia or with cardioplegia. In the latter situation, a cannula is inserted into the ascending aorta for delivery of antegrade cardioplegia and later aspiration of air. A cannula may be inserted into the coronary sinus through a purse-string suture in the right atrial wall. Cardioplegic solution is infused every 15 to 20 minutes either through the aortic root or retrogradely through the coronary sinus (see “ Methods of Myocardial Management during Cardiac Surgery ” in Chapter 3 ).

The pulmonary artery is examined to determine the location and extent of the aneurysm. If the aneurysm is confined to the pulmonary trunk, excising a portion of the anterior wall to establish a normal diameter and closing the defect with a continuous 4-0 or 5-0 polypropylene suture can be performed. ^{, ,} Alternatively, the aneurysmal segment can be excised and replaced with a woven polyester graft or pulmonary allograft. If the aneurysmal changes involve right and left pulmonary arteries as well, the aneurysmal segments are excised, and pulmonary trunk, right, and left pulmonary arteries are replaced with a woven polyester bifurcation graft or pulmonary allograft ( Fig. 25.18 ). If the pulmonary valve is abnormal, it can be replaced using a pulmonary valve allograft or a composite valved conduit (see “ Technique of Operation ” in Chapter 38 ). Other cardiac malformations, if present, are corrected.

Bifurcation graft for pulmonary artery aneurysm. (A) Aneurysm of pulmonary trunk with dilation of proximal segments of right and left pulmonary arteries. (B) Replacement of pulmonary valve, pulmonary trunk, and proximal segments of right and left pulmonary arteries with a pulmonary allograft.

When rewarming is completed, air is evacuated from the cardiac chambers, CPB is discontinued, and the procedure is completed in the standard manner (see “ Completing Cardiopulmonary Bypass ” in Section III of Chapter 2 ).

Patients with pulmonary arterial hypertension and giant pulmonary artery aneurysms may be considered for heart-lung transplant, but another option is bilateral lung transplantation and pulmonary artery reconstruction.

An example of this strategy is a patient with end-stage pulmonary arterial hypertension, unrepaired large patent ductus arteriosus, right pulmonary artery atresia, and a giant main pulmonary artery aneurysm ( Fig. 25.19 ). An intraoperative photograph of the aneurysm is shown in Fig. 25.20 . Bilateral lung transplantation and reconstruction of the pulmonary artery was performed using donor descending aorta and a tube constructed from bovine pericardium. The CT reconstruction is shown in Fig. 25.21 .

Preoperative computed tomography of a patient with severe pulmonary arterial hypertension, large patent ductus arteriosus, right pulmonary artery atresia, and main PA aneurysm. PA, pulmonary artery. Top, axial. Bottom, coronal.

(From Doi A, Gajera J, Niewodowski D, et al. Surgical management of giant pulmonary artery aneurysms in patients with severe pulmonary arterial hypertension. J Card Surg . 2022;37(4):1019-1025, with permission.)

Intraoperative photograph of the pulmonary artery aneurysm.

Postoperative computed tomography pulmonary angiogram—three-dimensional reconstruction.

(From Doi A, Gajera J, Niewodowski D, et al. Surgical management of giant pulmonary artery aneurysms in patients with severe pulmonary arterial hypertension. J Card Surg . 2022;37(4):1019-1025, with permission.)

Postoperative care is conducted as described in Chapter 5 .

Results of operative repair are primarily contained in isolated case reports. ^{, , , ,} Among patients undergoing elective operation, early results have been excellent. Little information regarding long-term outcomes is available.

Current data suggest that the natural history of PA aneurysms is benign even for severe PA aneurysm, or in patients with PA aneurysms who become pregnant. Thus, conservative management for PA aneurysm is appropriate, and the risk of PA dissection is low in the absence of pulmonary hypertension. The most common indication for repair of a PA aneurysm is in patients who have other indications for operation, such as congenital or acquired cardiac lesions, should have repair of large coexisting pulmonary artery aneurysms.

Pulmonary artery dissection (PAD) is separation of vessel layers of pulmonary arteries, most commonly of the pulmonary trunk, although it can extend into the major branches. It is a rare condition.

According to Shilkin and colleagues, the first reported case of PAD was by Helmbrecht in 1842. Fernando and colleagues were able to assemble 150 cases from the literature, and it does appear that the antemortem diagnosis of PAD has substantially increased since 2004. This may be due to increased recognition, although significant publication bias cannot be discounted. Although most cases of PAD are established at postmortem, there are a number of case reports of successful surgical management. ^,

PAD originates most commonly in the pulmonary trunk (71% of the 52 patients reviewed by Inayama and colleagues) and in the major branches of the pulmonary arteries. It is frequently associated with pulmonary hypertension, including Eisenmenger syndrome, but among patients who have hypertension, only a small percentage have pulmonary arterial hypertension. In the review of Inayama and colleagues, 28 patients had secondary pulmonary hypertension, and congenital cardiac malformations were present in 23 with patent ductus arteriosus being the most common. Marfan syndrome was present in only 1 of the 52 patients, although cystic medial degeneration was observed in the pulmonary arteries of 23 of 29 patients with detailed histologic studies. Pulmonary hypertension was present in 20 of these 23 patients.

In the majority of reported cases (86%), diagnosis of PAD was made at autopsy. Rupture of the pulmonary artery into the pericardial cavity or mediastinum or into a pleural space was a frequent finding.

Presenting symptoms are identical to those observed with acute aortic dissection and include severe chest pain, dyspnea, central cyanosis, and shock. Several days may elapse between onset of pain and rupture. The diagnosis may be made by imaging studies including CT ( Fig. 25.22 ), MRI, and echocardiography.

Intimal flap features determined on CT angiography. (Left) Sagittal MPR reconstruction revealed the primary entry tear (arrow) in the proximal main pulmonary trunk and retrograde extension of the intimal flap to the pulmonary valve. (Right) Volume rendered images demonstrate the relationship between the intimal flap and pulmonary artery root. MPR, multiplanar reconstruction.

(From Zhang C, Huang X, Li S, Yao H, Zhang B. Pulmonary artery dissection: a fatal complication of pulmonary hypertension. Case Rep Med . 2016;4739803, with permission.)

Prognosis of untreated PAD is extremely poor. Diagnosis has been infrequently made before death, and only a few patients have been successfully managed by surgical intervention. ^,

The number of successful repairs of PAD in the literature is small; therefore, a preferred strategy cannot be defined. The technique of operation that seems the most reasonable is identical to that described for treatment of pulmonary artery aneurysm (see “ Technique of Operation ” in the preceding section and Fig. 25.18 ). However, successful endovascular procedures have been described.

It is difficult to determine the outcomes of patients sustaining a PAD because of the small number of reported cases and the accompanying publication bias, the uncertain number of patients from the literature in whom the diagnosis was made postmortem, and the fact that PAD is invariably associated with pulmonary hypertension, substantially increasing the operative risk.

There are case reports ^, of patients with PAD not managed either surgically or by an endovascular procedure with prolonged survival, but these cases must be regarded as exceptions, as the usual nonoperative course is rupture of the pulmonary artery. One of the causes of unexpected sudden death in patients with pulmonary hypertension, regardless of the cause, may be due to PAD and classified as directly related to pulmonary hypertension.

However, the outcomes seem satisfactory for patients in whom the diagnosis of PAD is made promptly and an expeditious operation performed despite the invariable pulmonary hypertension. Several patients with severe pulmonary hypertension, including those with Eisenmenger syndrome and extensive dissection, have been successfully treated by heart/lung transplantation.

Because of the extremely poor prognosis associated with PAD, operative treatment should be considered for any patient in whom the diagnosis is established. An endovascular procedure should be considered in patients where the operative risk is thought to be prohibitively high.

Primary tumors of the pulmonary artery are malignant tumors, most commonly sarcomas, usually arising in the pulmonary trunk and extending into right and left pulmonary arteries. They commonly involve the pulmonary valve and may extend into the right ventricle. These tumors, although rare, are being reported with increasing frequency.

The first report of a sarcoma of the pulmonary trunk was by Mandelstamm in 1923. Early surgical treatment consisted of resecting the segment of pulmonary trunk containing tumor, pneumonectomy, or both. More recently, resecting and reconstructing the pulmonary arteries using CPB has been used.

Sarcomatous tumors arise from the intima of the pulmonary artery, most frequently from the dorsal surface of the pulmonary trunk. They rarely extend through the adventitia or invade surrounding structures. Pulmonary metastases are present in up to 60% of patients. Metastases to lymph nodes and other organs are less common. ^, Microscopic features are highly variable. In a review of 99 pulmonary sarcomas by Lyerly and colleagues, many cell types were represented, including leiomyosarcoma, myxofibrosarcoma, fibrosarcoma, chondrosarcoma, angiosarcoma, osteogenic sarcoma, and liposarcoma.

Lee and colleagues have made the point that in their series of 55 patients with pulmonary artery sarcoma, 91% had bilateral disease, implying that lung resection alone could never be curative.

Clinical presentation resembles that of more commonly occurring conditions such as chronic pulmonary TED. Symptoms include dyspnea, chest pain, cough, and hemoptysis. There are no characteristic physical findings. Diagnostic studies such as ventilation/perfusion scans, CT, echocardiography, and pulmonary angiography have only infrequently established the diagnosis preoperatively ( Fig. 25.23 ). ^, MRI with gadolinium contrast may be a useful diagnostic tool because tumor enhances more than bland thrombus. Fluorodeoxyglucose positron emission tomography (FDG-PET) may demonstrate increased uptake within the tumor. ^, Ventilation–perfusion scintigraphy scanning may help define the extensiveness of the tumor. In the review of Lyerly and colleagues, correct diagnosis was made at postmortem examination in 59% of cases and after surgical exploration in 31%.

Spiral chest computed tomography scan of a patient with sarcoma of the pulmonary arteries, showing massive filling defects in the right and left pulmonary arteries and near-total obliteration of right pulmonary arterial flow (arrows) . Patient was originally diagnosed with chronic pulmonary embolism and cor pulmonale.

(From Huang SS, Huang CH, Yang AH, Yu WC. Images in cardiovascular medicine. Solitary pulmonary artery intima sarcoma manifesting as pulmonary embolism and subacute cor pulmonale. Circulation . 2009;120:2269-2270.)

Median duration of survival from diagnosis is approximately 1.5 months without surgical resection. In a review by Blackmon and colleagues of 66 patients reported since 1990 who received some form of therapy (chemotherapy, irradiation, or surgery), 5-year survival was 18.5%.

The usual operation for this condition is PEA, outlined in section III of this chapter. There may be additional surgical modifications dictated by the pathology and likelihood of clearance of the tumor such as pneumonectomy and main pulmonary artery resection and pulmonary valve replacement. Pneumonectomy alone is very unlikely to be curative. In most circumstances, the therapeutic direction is palliation, but survival may be prolonged with aggressive surgical resection coupled with multimodal adjuvant therapy including targeted radiation and systemic chemo/immunotherapy.

Survival after surgery is very dependent on successful clearance of the tumor. In the series of 31 patients of Mussot and colleagues, 25 of whom underwent PEA (5 including pneumonectomy), 5 undergoing pneumonectomy alone, and in 1 patient, replacement of the right pulmonary artery alone, the 5-year survival was 22%. The review by Blackmon and colleagues found that the median survival for patients who had attempted curative resection was 36.5 ± 20.2 months and 11 ± 3 months for those with incomplete tumor excision. For those patients receiving multimodality adjuvant treatment, the median survival was 24.7 ± 8.5 months. In a series of 17 patients, of whom 11 underwent PEA, the mean survival was 37 months. PEA can be considered for palliative reasons to ease symptoms and possibly extend life. There are examples of quite aggressive surgical resection with surprising relatively prolonged survival. ^, Heart/lung transplantation has been performed for this condition ^, but is not advisable.

Because radical surgical resection likely represents the only chance for cure, operation should be considered in patients with no comorbid conditions that would preclude the use of CPB and who have no evidence of distant metastases. Adequate pulmonary reserve should be documented for patients who may require pneumonectomy. PEA can be considered for palliation.

Acquired disease of the systemic veins entails obstruction—partial or complete—of the superior vena cava (SVC) and inferior vena cava (IVC). While SVC syndrome is important and worthy of description, its surgical significance has diminished substantially with the development of endovascular approaches. Left and right brachiocephalic veins, including the jugular-subclavian vein confluence, are major tributaries of the SVC and may be considered collectively with conditions of the SVC. Congenital anomalies of the venae cavae and axillary vein conditions such as effort thrombosis are not considered in this chapter. Obstruction results from extrinsic compression, direct invasion by disease processes, or thrombosis. SVC syndrome is the result of venous hypertension in the head, neck, and arms caused by SVC obstruction.

William Hunter described the first recorded case of SVC syndrome in 1757 in a patient with syphilitic aneurysm of the aorta. SVC obstruction was due to compression by the aneurysm. William Osler described SVC compression in his classic text of 1892: “Along the convex border of the ascending part [of the aorta], aneurism frequently develops, and may grow to a large size… In this situation the sac is liable indeed to compress the superior vena cava, causing engorgement of the vessels of the head and arm.” William Stokes’ text of 1853 described SVC obstruction and noted the more frequent occurrence with cancer: “As an indication of intrathoracic tumour, an extensively varicose state of the superficial veins of the neck and thorax is probably less frequent in aneurismal than in cancerous disease… The superior cava may be adherent to the tumour, and become narrowed, not only by pressure, but by adhesion of its internal surfaces.”

The first successful bypass operations for SVC obstruction by Klassen and colleagues in 1951 and Bricker and McAfee in 1952 were performed using autologous femoral vein grafts. ^, In 1965, Hanlon and Danis used other large veins to replace or bypass the SVC, employing variously the femoral, subclavian, and jugular veins. In 1962, Benvenuto and colleagues constructed a composite panel graft from pieces of saphenous vein for replacing the SVC. A number of conduits had been tried, including autologous, homologous, and heterologous vein, aorta, and various synthetic materials. Scherck and colleagues concluded that autologous vein grafts of nearly the same size as the SVC were most likely to remain patent. Obtaining such a large autologous vein usually requires removing a large one from elsewhere in the body, with resultant venous drainage problems, or constructing a composite graft from a smaller one.

Synthetic grafts are attractive because of their convenience, availability, and the variety of sizes available. In 1973, Effeney and colleagues reported successful bypass of the SVC using polyester grafts. In 1977, Avasthi and Moghissi used a polyester graft interposed between the brachiocephalic vein on the left side and right atrial appendage to bypass the obstructed SVC. Thrombosis of polyester grafts limited success of the procedure. Expanded polytetrafluoroethylene (PTFE) was used successfully as a venous replacement conduit in experimental venous operations in dogs. Hiratzka and colleagues showed that PTFE and polyester were equally poor venous substitute conduits in the experimental setting, and that they did not approach the effective patency of autologous vein grafts. Reichle and colleagues suggested that this was because autologous vein grafts have a living endothelial surface even after initial endothelial desquamation, whereas prosthetic graft inner surfaces are composed of collagen matrix. Nevertheless, success using PTFE grafts has been reported. Antiplatelet-adhesive drugs may be of benefit in maintaining patency of PTFE grafts. Dartevelle and colleagues reported that 12 of 13 PTFE grafts used to replace the SVC were patent an average of 24 months after operation.

Composite vein grafts constructed from the saphenous or external jugular veins, in paneled or longitudinal fashion, have been used clinically for SVC bypass or replacement. ^, In 1974, Chiu and colleagues reported constructing a composite vein graft from the external jugular vein, which was matched to the size of the SVC. The donor vein was opened longitudinally and wrapped in spiral fashion around a tubular stent of approximately the same size as the SVC. Vein edges were then sutured together to form the conduit. The graft occluded in the initial three experiments in dogs. After that, however, 10 consecutive grafts remained patent for up to 15 months. This report prompted successful application of this technique in humans by Doty and Baker in 1976. Successful percutaneous balloon dilation of the SVC in a child was reported by Rocchini and colleagues in 1982. In 1986, Sherry and colleagues reported successful dilation of an SVC stricture caused by pacemaker electrodes in an adult. In 1987, Rosch and colleagues used an expandable wire stent to treat SVC obstruction caused by malignant disease that recurred after extensive radiation therapy. Endovascular approaches are now so effective that surgical relief of SVC obstruction is largely reserved for an unsuccessful endovascular procedure.