The differential diagnosis of a cardiac mass includes four entities: (1) echo artifact or normal variant; (2) thrombus; (3) vegetation; (4) cardiac tumor (Table 30.1). A thrombus usually occurs at specific cardiac locations in association with specific cardiac conditions (LV apex in patients with apical akinesis, right-sided chambers in patients with pacemaker leads). A vegetation arises from the free edge of a valve, on the side of the upstream chamber, and may occasionally involve the subvalvular apparatus; when large and visible, it is usually associated with a significant valvular regurgitation. A myxoma usually originates from the interatrial septum through a stalk, while a fibroelastoma often originates from the free edge of a valve, on the side of the downstream chamber. About 85% of primary cardiac tumors are benign, and of those, myxoma is the most common subtype. The relative frequency of myxoma in pathological and surgical series is 50% of all primary tumors (~50–75 % of benign tumors).1,2 The second most common cardiac tumor is papillary fibroelastoma (involves the mitral or aortic valve). Other benign cardiac tumors include lipomas, rhabdomyoma, and hemangiomas. Most valvular tumors are papillary fibroelastomas. Primary malignant cardiac tumors are very rare and include angiosarcoma, the most common type, and rhabdomyosarcoma. Secondary metastatic malignancies are 20 times more common than primary cardiac tumors. However, these malignancies often involve the pericardium leading to effusions, less commonly involve the myocardium, and least commonly involve the endocardium.3 In fact, a cavitary or endocardial mass is usually a primary cardiac tumor rather than a metastatic malignancy. Renal cell carcinoma is an exception which masquerades as a right-sided endocardial mass. Cardiac myxomas, more specifically, are characterized by polygonal cells in an extracellular matrix of acid-mucopolysaccharides. They are thought to arise from remnants of subendocardial primitive mesenchymal cells in the fossa ovalis and endocardium.4 Anatomically, myxomas typically originate from the interatrial septum (fossa ovalis) and extend into the LA (75%) or RA (15%) (Figure 30.1).5,6 About 3–4% of myxomas arise from the LV or RV wall. Rarely, atrial myxomas may arise from the mitral valve or the atrial wall. Myxomas are present at multiple locations in 5% of patients, more so in familial cases. Table 30.1 Echocardiographic features allowing the differential diagnosis of a cardiac mass. a Nodules of Arantius are small fibrous thickenings of the aortic leaflets edges, at the points where the leaflets abut. Lambl excrescences are small fibrous fibers arising from the edges of the aortic valve leaflets, mostly seen in patients older than 40 years. Figure 30.1 Apical four-chamber view showing a large left atrial mass (horizontal arrow). The mass does not seem to originate from the mitral valve (oblique arrow). It is round, smooth-surfaced with areas of lucencies (arrowhead). This is consistent with left atrial myxoma rather than vegetation. The median age at the time of diagnosis is 50–60 years, with an age range of 15–80 years and a slight female predominance.5 Most patients are symptomatic at the time of diagnosis (85%). Three types of symptoms are encountered: On echo, myxoma is characterized by an irregular shape with a “grape cluster” appearance, but it may also be round, smooth-surfaced. It is non-homogeneous, with areas of lucency (corresponding to hemorrhage) and sometimes calcifications. The diagnosis is usually established by the typical location and echocardiographic features (Figure 30.1). TEE helps confirm the diagnosis, as it shows the narrow stalk originating from the fossa ovalis, defines whether there is valvular invasion, and excludes multiple masses, which is important for surgical planning. MRI may also be used for that purpose; in light of its high extracellular water content, myxoma has a high intensity on T2 images. Treatment of cardiac myxomas is surgical. Despite being a benign tumor, a myxoma is potentially lethal because of intracavitary or valvular obstruction, embolization, and induction of conduction and rhythm disturbances, all of which may occur while awaiting surgical correction. Therefore, surgery is usually performed promptly, or urgently in some series, after the diagnosis is made. Recurrence may occur in case of incomplete resection, intraoperative dissemination, or growth from a new focus, and is seen in 1–3 % of sporadic cases (~20% of familial cases), mostly in the first 4 years after resection.7 Valvular fibroelastomas also appear to have a significant embolization risk, and warrant removal in case of a prior embolic event, large size ≥ 1 cm, or mobility. Furthermore, aortic fibroelastoma may prolapse across the left main and obstruct it, causing sudden death. Rhabdomyoma is the most common pediatric cardiac tumor. It may occur sporadically or in conjunction with tuberous sclerosis. It generally arises from the ventricular myocardium and regresses spontaneously (very good prognosis). Pregnancy is associated with a 50% increase in blood volume and with reduced systemic and pulmonary vascular resistances. Preload is increased while afterload is reduced, which leads to increased stroke volume. In addition, heart rate increases by 20%. All this increases cardiac output by 40–50%. The increase in blood volume and cardiac output peaks in the second trimester (24 weeks) then plateaus.8 Cardiac output decreases with supine position (caval compression) and increases with lateral position. Both SBP and DBP decline, reaching a nadir in mid-pregnancy, with a more marked drop of DBP (from the reduced vascular resistance). Systemic vascular resistance starts to rise in the third trimester, at which time BP slightly rises, although it remains lower than pre-conception, and cardiac output stops increasing. Cardiac output further increases during labor and delivery (60–80%), partly because of the high adrenergic tone, and partly because each uterine contraction pumps blood into the intravascular space. Epidural analgesia may reduce preload and limit the rise in cardiac output. After delivery, preload abruptly increases as IVC compression is relieved and as blood leaves the congested uterus over the next 1–3 days (“autotransfusion”). Thus, cardiac output continues to rise after delivery. Preload may also transiently decrease with bleeding, and this is more likely to occur with cesarean delivery as it incurs more blood loss (1000 ml vs. 500 ml). The eventual increase in preload explains how pulmonary edema may occur in the first few days after delivery. Afterload increases with uterine contractions, then abruptly drops as the uterus relaxes post-delivery. A loud S1, an S3, and a mild midsystolic murmur (2 or 3/6) may be normally heard. A mild RV heave and a displaced apical impulse may be felt. A persistently split S2, an S4, a loud systolic murmur, or any diastolic murmur are abnormal. Severe pulmonary hypertension is associated with a 30–50% maternal mortality and is an absolute contraindication to pregnancy.9,10 The increased preload may lead to pulmonary edema, while the striking afterload reduction in a patient with fixed obstruction and fixed cardiac output may lead to hypotension and collapse.11 This may even be more prominent around delivery, when a sudden increase in preload and a drop in afterload may occur. In patients planning to conceive, severe AS should be corrected before pregnancy, even if asymptomatic (class IIa); patients with non-calcified AS may be treated with percutaneous valvuloplasty to avoid the hazard of prosthetic valves. If AS is discovered during pregnancy, percutaneous valvuloplasty may need to be performed in patients who develop severe symptoms. Pregnancy is risky even in asymptomatic patients. Yet, a subset of asymptomatic severe AS patients may have a low mortality during pregnancy without the need for valve intervention; this subset consists of patients who are asymptomatic on stress testing with good functional capacity and BP response, and normal BNP. There is no need to discourage pregnancy in these patients (class IIb).9 The increased preload and tachycardia associated with pregnancy exaggerate the transmitral gradient, particularly in the third trimester and during delivery.11 In patients planning to conceive, MS should be corrected before pregnancy, even if asymptomatic with no standard indication for PMBV. Otherwise, if pregnancy occurs before correction, β-blockers and judicious doses of diuretics are used during pregnancy. PMBV may need to be performed in pregnant patients with uncontrolled symptoms. In one study, patients with dilated cardiomyopathy and moderate or severe LV dysfunction or NYHA class III/IV (mostly idiopathic) had a 70–80% risk of cardiac events during pregnancy or postpartum. These consisted mainly of HF decompensations, arrhythmias (AF, atrial flutter), and one transient ischemic attack (among 18 patients). These complications were managed medically and no maternal death occurred; one fetal death occurred during maternal pulmonary edema.12,13 Pregnancy is preferably avoided in these patients, but some patients may want to proceed in light of the limited mortality risk. Those who proceed with pregnancy may continue β-blocker therapy, hydralazine, digoxin, and low-dose diuretic; ACE-I and aldosterone antagonists are stopped. Cyanosis, by itself, reduces fetal growth, particularly when arterial O2 saturation is <85% at rest or stress. In the absence of HF or ventricular dysfunction, the maternal risk may be low, but the fetal risk is always high when O2 saturation <85%. In fact, fetal survival is only 12% in the latter case. In corrected tetralogy of Fallot, carefully assess for any residual defect before giving advice about the safety of pregnancy. In the absence of significant VSD, pulmonic stenosis, or pulmonic regurgitation, and in the case of a normal PA pressure and RV function, pregnancy is well tolerated. In a Fontan patient with normal ventricular function, no cyanosis, and no significant valvular regurgitation, pregnancy may be possible. Note: Antibiotic prophylaxis is not recommended in women with native valvular disease undergoing vaginal delivery, except for a prior history of endocarditis. Cesarean delivery attenuates the rise in cardiac output at the price of more blood loss and more abrupt hemodynamic fluctuations than vaginal delivery, especially because spinal anesthesia is usually needed with cesarean delivery. Also, cesarean delivery increases the risk of venous thrombosis. Thus, vaginal delivery with assisted second stage is preferred in the majority of patients; epidural anesthesia is advised to limit the increase in cardiac output (unless the patient is anticoagulated). Cesarean delivery is indicated for obstetric reasons and in the following three cardiac conditions:15 Patients with mechanical prosthetic valves have a strikingly increased risk of valve thrombosis and thromboembolism during pregnancy. One large meta-analysis has shown that even when adequately anticoagulated with warfarin throughout pregnancy, the thromboembolic risk is ~4%. The risk drastically increases when heparin is substituted for warfarin between weeks 6 and 12 (the risk increases from 4% to 9%, even if heparin is only used for 6 weeks), with a doubling of the maternal mortality risk (from 2% to 4%).18 The thromboembolic risk is much higher if adjusted-dose unfractionated heparin is used throughout pregnancy (25%). Those risks are seen even in modern registries using modern valves and proper heparin and LMWH dosing.19 Conversely, while warfarin is a much more effective anticoagulant in pregnancy than heparin, it traverses the placental barrier and is associated with a fetopathy risk (mainly bone and facial hypoplasia, sometimes mental retardation), and a risk of spontaneous abortion. This risk mostly results from warfarin administration between 6 and 12 weeks, especially if the required dose is >5 mg/day (risk >30%). The same meta-analysis has shown that when unfractionated heparin is substituted at or before 6 weeks of gestation, the risk of fetopathy is eliminated, at the price of a drastic increase in maternal thromboembolism. The thrombotic risk may be lower with LMWH vs. UFH, when LMWH is adjusted according to anti-Xa levels, but remains high at 4-8% even with adequate anti-Xa levels.19 Heparin is a large molecule that does not traverse the placental barrier, and it is safe from the fetal standpoint. Thus, continuous intravenous UFH (rather than subcutaneous heparin) or preferably, subcutaneous LMWH with anti-Xa monitoring may be substituted for warfarin as soon as pregnancy is recognized, ideally before 6 weeks, and administered until 12 weeks (both agents receive a class IIa recommendation if the required warfarin dose is >5 mg/d, class IIb if the required warfarin dose is ≤ 5 mg/d). Warfarin is resumed after 12 weeks, until 36 weeks. Alternatively, when the risk of valve thrombosis is high and the warfarin dose is ≤ 5 mg, continuous warfarin therapy throughout 36 weeks may be considered and discussed with the patient (class IIa recommendation). The risk of embryopathy is reduced (<3%) when warfarin dose is ≤ 5 mg, but not eliminated; in these patients, the combined maternal plus fetal risk is lowest with continuous warfarin therapy. Intravenous heparin is started at 36 weeks, 2–3 weeks before the anticipated delivery, to prevent the fetal intracranial hemorrhage associated with warfarin (the latter has a longer half-life in the fetus). When UFH is used in the substitution period, PTT should be monitored and kept over twice the control. When LMWH is used, anti-Xa activity should be measured 4–6 hours post-injection at least once weekly and kept at 0.8–1.2 units/ml. With warfarin, the INR goal is 2.5–3.5. Aspirin should be continued along with anticoagulation. Both warfarin and heparin are compatible with breastfeeding , as none of them is secreted in breast milk.20 PPCM is LV systolic dysfunction that develops in the last month of pregnancy or within 5 months postpartum, without any prior heart disease. Hypertension frequently coexists with PPCM and is a risk factor for PPCM. Older age, African-American race, multiparity, and multifetal pregnancies are other risk factors. Depending on its severity, hypertension does not necessarily imply a diagnosis of hypertensive cardiomyopathy and is consistent with PPCM.20,21 In fact, severe acute HTN usually causes pulmonary edema through acute diastolic rather than systolic dysfunction.22 The mechanism of PPCM is likely immunological. LV function fully recovers in ~55–60% of PPCM cases within 6 months of the diagnosis. Before recovery, however, PPCM is associated with a significant risk of complications, including a mortality of 3–10% (sudden death or HF death, mainly within 6 months of the diagnosis), severe progressive HF requiring heart transplantation in 6%, and thromboembolic complications.20,21 PPCM may be associated with a higher risk of LV thrombus than other forms of dilated cardiomyopathy, and potentially a higher risk of embolization. This higher thromboembolic risk may be due to the hypercoagulable state of pregnancy and the first 2 postpartum months. Similarly to any systolic HF, standard HF therapy is used, even if it is unclear whether this therapy specifically increases the recovery of PPCM. ACE inhibitors are contraindicated during pregnancy but are generally safe during lactation. PPCM is thus treated with β-blockers, hydralazine, digoxin, and loop diuretics during pregnancy, and, additionally, ACE-I and spironolactone in the postpartum, including in breastfeeding women. Since PPCM is associated with a high thromboembolic risk, an expert review suggests anticoagulation therapy until EF improves to over 35%.20 If PPCM recovers, the tapering and discontinuation of these drugs may be safe >6 months after full recovery, but close monitoring is required, as late deterioration of LV function has been described.23 PPCM is associated with a high early risk of sudden death before LV function eventually recovers. Since this risk of sudden death is only transient in patients who eventually recover, a wearable defibrillator vest rather than an ICD may be justified. ICD is indicated in patients who do not recover their LV function within 6 months of medical therapy. Breastfeeding is generally safe, but may be avoided in severe cases to reduce metabolic demands. Subsequent pregnancies should be avoided in patients with PPCM, particularly in those who do not recover their LV function. In one report, pregnancy was associated with a 20% mortality and 50% risk of worsening of LV function in patients with persistent LV dysfunction; in those who recovered LV function, pregnancy was safer, with no fatality, but a 20% risk of relapse.24 Table 30.2 Cardiovascular drugs and pregnancy. Lactation– The 3 main HF drugs (ACE-Is, ß-blockers, and spironolactone) and furosemide are generally safe during lactation. More specifically, ACE-I is secreted in breast milk in very small amount, hence it may be used during lactation (captopril, benazepril, enalapril) with close follow-up of the child’s weight. β-Blockers (labetolol, metoprolol), digoxin, and hydralazine are only secreted in a small amount in milk, and may be used during lactation Pregnancy is associated with an increased risk of arrhythmias, whether structural heart disease is present or not. There is a significant increase in the risk of SVT, especially in the third trimester (AVNRT, AVRT, incessant atrial tachycardia). AF and atrial flutter are rare during pregnancy and are usually associated with cardiomyopathies, valvular or congenital heart disease, or hyperthyroidism. AF may rarely be seen in healthy pregnancies (lone AF). Carotid sinus massage is safe in pregnancy. Adenosine, β-blockers, or calcium channel blockers may be used for SVT. DC cardioversion is also safe and may be used, if needed, for hemodynamic instability. The risk of MI increases three- to fourfold during pregnancy, especially during the third trimester and the first 6 weeks postpartum. The MI is most commonly a STEMI (75%), and usually occurs in patients older than 30. It is associated with a high mortality of 7–11%. In case series where angiography or autopsy was performed, the following processes were found:25,26 In a more modern series, coronary artery dissection was the most common cause of pregnancy-related MI (43%).26 Coronary dissection is relatively more frequent in the postpartum than the antepartum period. Patients with coronary artery dissection have an increased risk of iatrogenic coronary dissection during the contrast injections of diagnostic angiography and a risk of further propagating the dissection during PCI; thus, PCI may be reserved for severe obstruction/occlusion of proximal segments with impaired flow and active ischemia.26 Also, fibrinolytic therapy is contraindicated in coronary dissection. Three first line therapies: Methyldopa, β-blockers (especially labetalol), nifedipine. Aspirin may be used to prevent pre-eclampsia in high-risk patients. About 10% of patients with pre-eclampsia develop pulmonary edema. Yet pre-eclampsia, per se, does not induce LV systolic dysfunction, even when assessed by echo strain imaging. It induces LV diastolic dysfunction and may induce acute diastolic HF with elevated LA pressure, RV failure and elevated BNP in ~10% of cases.29 Pericardial effusion is the most common cardiac manifestation of HIV infection, with an incidence of 11% per year in patients with CD4 count <200 not receiving antiretroviral therapy. It is usually asymptomatic and small but is seen with lower CD4 counts, which implies a more advanced disease and a 2.2× increase in adjusted mortality despite the usually small size.30 Patients with a moderate or large effusion may have a high risk of progression to tamponade. Also, a large or symptomatic effusion frequently, in over 50% of the cases, has a specific diagnosis: infectious (tuberculosis, purulent, opportunistic infection), or malignant (especially lymphoma or Kaposi sarcoma).31 See Chapter 5. The prevalence of pulmonary arterial hypertension (PAH) in HIV is ~0.5%. PH may also be due to lung disease or left HF, which increases the overall prevalence of any PH in HIV, particularly mild PH, up to 30%.32 As opposed to myocardial and pericardial processes, PAH does not appear to correlate with CD4 count, and was described in patients with CD4 count over 900.33 Pathologically, lesions are similar to idiopathic PAH (plexiform arteriopathy). PAH results from circulating cytokines or circulating HIV antigens activating endothelial cells. Antiretroviral therapy improves survival but does not clearly have a direct effect on PAH. Epoprostenol and bosentan were effective in small studies.34 Patients with HIV have accelerated atherosclerosis and an almost doubled risk of MI, particularly HIV patients older than 50.35 The risk of MI is further increased by protease inhibitors, which increase triglycerides and the number of small LDL particles, and reduce HDL. Truncal fat redistribution (lipodystrophy) may occur with HIV regardless of the type of therapy and may lead to metabolic syndrome. Cocaine induces myocardial ischemia through several mechanisms: All of these effects are strongly promoted by concomitant cigarette or alcohol use (alcohol is synergistic with cocaine). Fifty percent of patients with cocaine-related MI have normal coronaries. Chest pain mainly occurs within 1 hour of cocaine use, but can occur up to several hours later (up to 36–96 hours later), because the concentration of active metabolites increases hours later and may lead to delayed vasoconstriction. Between 7% and 20% of patients presenting with chest pain to urban emergency units have a positive cocaine screen.36 Approximately 6% of patients with cocaine-associated chest pain have MI (as manifested by elevated CK or troponin), half of whom have normal coronary arteries.36 The remaining patients have ischemia that is not sustained enough to lead to MI, or non-cardiac pleuritic pain. MI is difficult to diagnose by ECG, because many cocaine users have an abnormal baseline ECG with ST elevation (early repolarization, LVH). On the other hand, ST elevation can be related to spasm rather than thrombotic occlusion. Thus, ST elevation is sensitive but not very specific in cocaine users. Cocaine use is diagnosed by a urinary screen of both cocaine and its metabolites. Cocaine half-life is 60–90 minutes, but its metabolites persist 24–72 hours. In chronic high-dose users, cocaine metabolites may be found for up to 2 weeks.
30
Miscellaneous Cardiac Topics: Cardiac Masses and Tumors, Pregnancy, HIV and Heart Disease, Cocaine and the Heart, Chemotherapy and Heart Disease, Chest X-Ray
1. CARDIAC MASSES
I. Differential diagnosis of a cardiac mass
II. Cardiac tumors; focus on atrial myxoma
A. General features
Thrombus occurs in association with specific cardiac conditions at the following locations:
Morphology: myxoma is mobile, irregularly shaped (“grape cluster” appearance) with lucencies ± calcifications. This morphology may simulate vegetation. Unlike vegetation, myxoma may also be round and smooth-surfaced
B. Clinical presentation and diagnosis of myxoma
C. Treatment
2. PREGNANCY AND HEART DISEASE
I. High-risk cardiac conditions during which pregnancy is better avoided9
A. Eisenmenger syndrome, or primary or secondary severe pulmonary hypertension
B. Severe AS, even if asymptomatic
C. Severe MS, even if asymptomatic
D. Any cardiomyopathy or valvular disease with EF < 30% or NYHA III/IV
E. Aortic root dilatation ≥ 45 mm
F. Complex cyanotic congenital heart disease (tetralogy of Fallot, Ebstein, Fontan circulation)
II. Cardiac conditions that are usually well tolerated during pregnancy, but in which careful cardiac evaluation and clinical and echo follow-up are warranted9
III. Cardiac indications for cesarean section
IV. Mechanical prosthetic valves in pregnancy: anticoagulation management
V. Peripartum cardiomyopathy (PPCM)
A. Prognosis, LV recovery
B. Treatment
VI. Cardiovascular drugs during pregnancy (see Table 30.2)
VII. Arrhythmias during pregnancy
VIII. MI and pregnancy
IX. Hypertension and pregnancy
A. Types
B. Treatment
C.Pre-eclampsia and HF
3. HIV AND HEART DISEASE
I. Pericardial disease
II. HIV cardiomyopathy
III. Pulmonary hypertension (PH)
IV. CAD
4. COCAINE AND THE HEART
I. Myocardial ischemia
A. Causes
B. Presentation
C. Diagnosis
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