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Cardiac Tumor
Definition
Cardiac tumors include benign and malignant neoplasms arising within the cardiac chambers or in the myocardium. Metastatic neoplasms to the heart are not included.
Historical Note
First recognition of a heart tumor is attributed to Columbus in 1559, followed by Malpighi, who in 1666 wrote a dissertation entitled “De polypo cordis.” Morgagni wrote of heart tumors in 1762. By 1931, Yater was able to publish an extensive dissertation and tabulation of primary cardiac tumors using a classification similar to that used today. Clinical diagnosis of a primary tumor—a sarcoma—was first recorded in 1934. The first antemortem diagnosis of a myxoma was made in 1951 using angiography. A major diagnostic landmark was echocardiographic diagnosis of a left atrial myxoma in 1968, which was confirmed at operation and successfully treated. In 1934, Beck partly removed an intrapericardial teratoma, and in 1951 Maurer successfully excised an intrapericardial lipoma. Among the earliest surgical approaches to myxomas was that of Bahnson and Newman, who in 1952 removed a myxoma from the right atrium via a right anterior thoracotomy using a short period of caval occlusion at normothermia. The patient died 24 days later of complications related to transfusion and electrolyte imbalance. Using cardiopulmonary bypass (CPB), Crafoord in 1954 successfully excised a myxoma from the left atrium, as did Bigelow in 1955, using hypothermia and inflow occlusion. Successful excision of a right atrial myxoma was reported in 1957 and in 1958. A left ventricular myxoma was excised in 1959 by Kay. The first successful excision of a right ventricular myxoma was reported in 1960. By 1964, 60 intracardiac myxomas had been successfully removed. Biatrial myxomas were first removed in 1967. In 1967, Gerbode and colleagues described recurrence of a left atrial myxoma 4 years after initial excision.
Types Of Cardiac Tumors
In a study from the Armed Forces Institute of Pathology, approximately 70% of cardiac tumors were benign and 30% malignant and potentially capable of invasion or metastasis ( Table 18-1 ). In a more recent study of 533 primary tumors removed surgically, 10% were malignant.
Table 18-1
Prevalence of Neoplasms of the Heart and Pericardium
Data from McAllister and Fenoglio.
| Type | No. | % |
|---|---|---|
| Benign Tumors | ||
| Myxoma | 130 | 29 |
| Lipoma | 45 | 10.1 |
| Papillary fibroelastoma | 42 | 9.5 |
| Rhabdomyoma | 36 | 8.1 |
| Fibroma | 17 | 3.8 |
| Hemangioma | 15 | 3.4 |
| Teratoma | 14 | 3.2 |
| Mesothelioma of AV node | 12 | 2.7 |
| Granular cell tumor | 3 | 0.7 |
| Neurofibroma | 3 | 0.7 |
| Lymphangioma | 2 | 0.5 |
| S ubtotal | 319 | 72 |
| Malignant Tumors | ||
| Angiosarcoma | 39 | 8.8 |
| Rhabdomyosarcoma | 26 | 5.8 |
| Mesothelioma | 19 | 4.2 |
| Fibrosarcoma | 14 | 3.2 |
| Malignant lymphoma | 7 | 1.6 |
| Extraskeletal osteosarcoma | 5 | 1.1 |
| Neurogenic sarcoma | 4 | 0.9 |
| Malignant teratoma | 4 | 0.9 |
| Thymoma | 4 | 0.9 |
| Leiomyosarcoma | 1 | 0.2 |
| Liposarcoma | 1 | 0.2 |
| Synovial sarcoma | 1 | 0.2 |
| S ubtotal | 125 | 28 |
| T otal | 444 | 100 |
Key: AV, Atrioventricular.
Section I
Myxoma
Definition
Cardiac myxomas are primary cardiac tumors that are generally pedunculated but may have a broad base. Cells are uniform, small, and polygonal, with round or oval nuclei and a moderate amount of cytoplasm. They lie in a myxomatous stroma in which other elements may be seen. One feature that distinguishes them from thrombi is that they are covered by endothelium and have endothelium-lined crevices and clefts.
Morphology
Myxomas are intracavitary tumors occurring within any of the cardiac chambers, but they have a predilection for the atria, particularly the left. They are usually 5 to 6 cm in diameter, with a range of 1 to 15 cm. Characteristically, they are polypoid and pedunculated, projecting into a cardiac chamber. They can be gelatinous or mucoid, often with areas of hemorrhage. Generally, they are not sessile but have a short, broad-based attachment. The external surface of papillary forms of the neoplasm consists of a frondlike mass that is friable and likely to produce emboli.
Histology
Myxomas are composed of cells, primitive capillaries, and foci of extramedullary hematopoiesis within a myxoid matrix of acid mucopolysaccharide. The stroma contains variable numbers of reticulocytes and elastin fibers, smooth muscle cells, and collagen deposits. The matrix also contains polygonal cells with scant eosinophilic cytoplasm, either single and stellate or multinuclear and in small nests. At the periphery of the tumor, the cells form a monolayer with clustering in the crevices, thereby simulating primitive capillaries. The stalk has abundant large arteries and veins that communicate with the subendocardium, and at this interface, lymphocytes and plasma cells are prominent. Microscopic foci of calcium and areas of metaplastic bone are found in 10% of myxomas. The nucleus of the polygonal cells is typically irregular and slightly hyperchromatic, but mitoses are not seen. The cells contain fine parallel filaments similar to those seen in glomangioma and fibromyxosarcoma. These filaments are believed to be the contractile components of smooth muscle cells. Immunologically identifiable smooth muscle–type filaments are recognized in endocardial cells, which are more abundant in the left atrium, especially in the region of the fossa ovalis, than in other chambers.
Tumor Biology
The notion that myxomas are derived from thrombi has been thoroughly dispelled. Ferrans and Roberts believe the organelle content of myxoma cells does not provide sufficient information to determine the cell of origin. Although myxoma cells have a “vasoformative” tendency, in their view the cytoarchitectural features of the variously differentiated blood vessel–like structures differ from those of normal blood vessels. Thus, myxomas are considered to arise from pluripotential mesenchymal cells capable of differentiating into various types of cells, a view supported by the finding of bone and bone marrow tissue in myxomas. Histologic examination of the atrial septum in 11 autopsied patients younger than age 4 months revealed myxomatous or myxofibrous tissue in the endocardium near the fossa ovalis, further supporting the concept that myxomas are derived from embryonal undifferentiated mesenchymal cells, perhaps during endothelial-mesenchymal transformation, leading to cardiac septation and valve formation.
Based on immunohistochemical identification of three neuroendocrine markers in 24 excised atrial myxomas, Krikler and colleagues have suggested that these tumors originate from endocardial sensory nerve tissue. Occasional association of cardiac myxomas with cutaneous leiomyomatosis and systemic findings such as fever, hypergammaglobulinemia, and weight loss resemble manifestations of other tumors of neural origin. Increasing numbers of reports document the malignant potential of myxomas. Extensive local invasion has been noted. Death attributable to metastatic spread of an atrial myxoma was once reported as a result of fatal brainstem compression from an expanding cerebellar mass with histologic features identical to those of a large, pedunculated left atrial myxoma also found at autopsy. There have been many reports of local recurrence and of distant metastases with invasion of vessel walls, aneurysmal change, and independent growth. Transgression beyond a blood vessel has also been noted.
Atrial Myxoma
Most atrial myxomas, whether left or right, arise from the atrial septum, usually from the region of the limbus of the fossa ovalis. About 10% have other sites of origin, particularly the posterior and anterior atrial walls and the appendage (in order of frequency). Importantly, atrial masses thought to be myxomas but not originating from the intraatrial septum may have more complex pathology. On the left atrial side, they may be extensions of hilar lung tumors such as mesothelioma, sarcoma, or carcinoma. On the right side, they may be intracaval extensions of renal or uterine tumors. Most myxomas—80% to 90%—are in the left atrium. Right atrial myxomas tend to be more solid and sessile than left atrial myxomas, with a wider attachment to the atrial wall or septum. In one reported case, an atrial myxoma presenting in the right atrium arose from the inferior vena cava. Atrial myxomas may be multicentric (within a single chamber) or biatrial. The most common arrangement (75%) of biatrial tumors involves attachment of two stalks to opposite sides of the same area of the septum. Of 312 cases of right and left atrial myxomas reviewed by Newman and colleagues, only two were complicated by presence of an atrial septal defect ; Natarajan and colleagues reported four cases. Such cases may have right-to-left shunts.
Ventricular Myxoma
Found commonly on the right ventricular free wall or ventricular septum, ventricular myxomas are sometimes described as infiltrating the ventricular myocardium. In about 15% of reported cases, right ventricular myxomas are associated with other cardiac myxomas. Left ventricular myxomas are rare. Both right and left ventricular myxomas can extend into the outflow tract and cause partial outflow tract obstruction.
Valvar Myxoma
Myxomas arising from the mitral, tricuspid, or pulmonary valves have been reported.
Clinical Features And Diagnostic Criteria
Pathophysiology
Myxomas may produce (1) symptoms of hemodynamic derangement from obstruction of flow within the cardiac chambers or deformation of a cardiac valve, (2) symptoms associated with embolization, and (3) constitutional symptoms, the least common manifestation. In rare circumstances, atrial myxomas may become infected; only 2 of 12 reported cases were diagnosed before death. Central nervous system embolism has been a constant association.
Hemodynamic Derangement
Myxomas may obstruct pulmonary or systemic venous drainage or may impair flow across the atrioventricular valves, the likelihood of these events being greater with larger tumors. The obstruction is characteristically progressive. When obstruction is intermittent, syncope, often related to postural change, or sudden death may occur. This happens in less than one fourth of patients with left atrial myxomas, about one third of those with right atrial or right ventricular myxomas, and about half of those with left ventricular myxomas. Impairment of valve closure, either by obstruction or leaflet damage, may cause regurgitation. Valves may be structurally damaged by frequent tumor impingement, a sequence that also causes regurgitation. Although regurgitation is the dominant abnormality, obstruction predominates in a few patients. Symptoms are commonly of short duration, are episodic, and may be associated with syncope.
Embolism
A major feature of cardiac myxomas is embolization. Emboli may arise from tumor fragmentation or detachment of the entire tumor, or from thrombi or infected foci on the surface of the neoplasm. Systemic emboli occur in 30% to 45% of patients with left atrial myxomas. They have been reported in every organ and may occlude coronary arteries. About 50% of emboli involve intracranial or extracranial arteries to the central nervous system. Cerebral emboli characteristically cause major permanent neurologic deficits. On rare occasions, they are amenable to excision. Large emboli may obstruct the aortic bifurcation. Although left ventricular myxomas are rare, prevalence of embolism from them is high (64%), apparently unrelated to tumor size, and greater to the brain than elsewhere. Left atrial myxomas that come to attention because of embolization tend to be small when examined after that event. Embolism from right-sided tumors occurs in about 10% of cases and may cause massive fatal pulmonary obstruction. However, pulmonary arterial obstruction from this mechanism is much less common than true thromboembolism to the pulmonary arteries in patients who have sustained systemic tumor emboli from a left atrial myxoma. Multiple emboli from right-sided tumors may be a cause of pulmonary hypertension. Paradoxical embolism is rare.
Constitutional Manifestations
In about 30% of patients, the only manifestation of a cardiac myxoma is a plethora of constitutional symptoms and certain laboratory findings. Large left atrial myxomas are particularly apt to produce constitutional symptoms. Symptoms include fever, weight loss, clubbing of the fingers and toes, Raynaud phenomenon, and myalgia and arthralgia. By themselves, these findings are not pathognomonic. Because the presence of antibodies to fresh heart muscle has been demonstrated preoperatively in some patients, with appropriate postoperative diminution, it is speculated that an immune reaction to the neoplasm or to heart muscle mediated by presence of the neoplasm may cause the constitutional symptoms. Total globulin levels are often elevated, and the electrophoretic patterns may reveal prominent α 2 -, β 1 -, or heterogeneous γ-globulin peaks. Immunoelectrophoresis localizes the elevated globulins in either the immunoglobulin (Ig)M or IgA fractions. Elevated globulin levels are associated with an increased erythrocyte sedimentation rate and C-reactive protein levels. Further nonspecific symptoms may be related to seeding of multiple small emboli in muscle and joints, and hemorrhage or degeneration within the tumor. Other unusual manifestations of cardiac myxomas include polycythemia with or without associated arterial hypoxia, and clubbing (with both left and right atrial myxomas) associated with a right-to-left shunt at the atrial level through a patent foramen ovale or atrial septal defect. Hemolytic anemia occurs in about one third of cases, particularly in association with a calcified myxoma; this and the thrombocytopenia that sometimes occurs are probably due to mechanical destruction of formed blood elements. These features are reversible with tumor removal.
Familial versus Nonfamilial Myxoma
Nearly all solitary myxomas have a normal DNA ploidy, and nearly all are nonfamilial. Nonfamilial (“sporadic”) cardiac myxomas are disorders primarily of middle-aged women. The tumors are usually single (94%) and in the left atrium (about 75%); they uncommonly have associated conditions, they rarely recur, and only about 20% have abnormal DNA ploidy.
Myxomas have a familial occurrence in about 5% of patients. They have a pattern of Mendelian dominant inheritance and are primarily disorders of young men. They are less common in the left atrium (62%), are more often multiple (33%), and in about 20% of patients are associated with unusual conditions. These conditions include Sertoli cell tumors of the testes, Cushing syndrome as a result of primary adrenocortical nodular dysplasia, pituitary tumors, centrofacial and labial lentiginosis (brown macules with regular edges, sometimes termed spotty pigmentation ), cutaneous myxomas, and multiple myxoid mammary fibroadenomas. Familial myxomas have the same histologic appearance as nonfamilial myxomas and produce the same symptoms. However, they have a strong tendency to recur. Some patients with these complex findings have no identifiable cardiac myxoma; in a few others the myxoma has been found unexpectedly at autopsy. Familial cardiac myxomas are aneuploid in virtually all cases, supporting the concept that they are neoplasms.
Symptoms
Left atrial myxomas produce symptoms similar to those of mitral stenosis (see Chapter 11 ) in most patients, with dyspnea and hemoptysis predominating. Symptoms are commonly of short duration, episodic, and associated with syncope. They may rapidly become severe and intractable and are associated with heart failure. Right atrial myxomas may also produce episodic symptoms, and these may progress rapidly. Abdominal protuberance from hepatomegaly and ascites and peripheral edema are frequent presenting complaints. In the review by Morrisey and colleagues, all 18 patients had right heart failure, with a prominent a wave, raised venous pressure, hepatomegaly, ascites, and peripheral edema ; absence of orthopnea and paroxysmal nocturnal dyspnea was notable. Symptoms that result from embolization include neurologic deficits, coldness and pain in an extremity, angina or infarction from coronary embolization, and dyspnea from pulmonary embolization. Constitutional symptoms may be subtle or absent when the tumor is small, but occasionally constitute the entire symptomatology.
Signs
Diagnosis of atrial myxoma is sometimes made immediately after hospital admission by histologic examination of an embolus removed from a peripheral artery. However, absence of myxoma cells in the embolus does not rule out myxoma, because thrombus forming on the neoplasm may be the cause of the embolism. Before the advent of echocardiography, interpretation of auscultatory findings for left atrial myxomas was aided by a combination of phonocardiographic and hemodynamic studies. A loud first heart sound is prolonged by vibrations coinciding with the c wave of the left atrial pressure tracing and also with a characteristic notch in the left ventricular pressure curve; these vibrations occur after mitral valve closure when the tumor momentarily comes to rest in the left atrium. For mobile tumors moving from the left ventricle to the left atrium in early systole, a notch in the ascending limb of the left ventricular pressure tracing is attributed to a sudden increase in left atrial volume, which itself is manifested in the left atrial pressure pulse by a prominent c wave and subsequent dominant v wave. Accordingly, the first heart sound may be preceded by a loud ejection sound resulting from forceful ejection of the tumor from the left ventricle back into the left atrium.
When the tumor stays in the left atrium during the entire cardiac cycle, the diastolic murmur and pressure tracings may be indistinguishable from those of mitral stenosis (i.e., there is no notch in the ventricular pressure wave, and the y descent is relatively slow). The second heart sound is normally split, of low intensity, and followed by a third heart sound described as either an opening snap or a ventricular gallop. The opening snap occurs after the mitral valve opens and is thought to be due either to the tumor striking the heart wall or to the diastolic sound of mitral regurgitation caused by increased blood flow. Systolic murmurs have also been recorded and have been attributed to associated mitral regurgitation.
With right atrial myxomas, a loud early systolic sound is heard, usually regarded as a widely split first heart sound, corresponding to expulsion of the tumor from the right ventricle. This sound is likely to correspond to a notch in the upstroke of the right ventricular pressure curve. A pulmonary ejection murmur with a delayed and accentuated pulmonic second sound and an early, late, or prolonged tricuspid diastolic murmur or rumble is heard. A systolic murmur is due to tricuspid regurgitation.
Ventricular myxomas are sufficiently rare that their auscultatory features are not fully known, but murmurs may suggest aortic or pulmonary stenosis. Occasionally, friction rubs are heard, presumably a result of physical contact of the tumor with the endocardium of one of the cardiac chambers. Rarely, patients presenting with constitutional manifestations exhibit cyanosis and clubbing of the fingers and toes, or a gallop rhythm and sinus tachycardia.
Laboratory Studies
Results of laboratory studies are usually normal. In rare instances of presentation with constitutional manifestations, some findings may be characteristic but not pathognomonic. Among them are anemia, thrombocytopenia, and findings associated with an immune response (see “ Constitutional Manifestations ” earlier in this section).
Electrocardiography
Electrocardiographic findings associated with myxomas are not specific, but include arrhythmias and conduction disturbances, particularly atrial fibrillation and bundle branch block, and abnormal P waves.
Chest Radiography
Features on a plain chest radiograph are not specific. Generalized cardiomegaly or specific chamber enlargement may be evident, particularly in the case of large left atrial myxomas causing obstruction. Septal lines, especially at the base and in the mid-zone of the lung, are fairly common findings because of coexisting pulmonary venous hypertension.
Echocardiography
Transthoracic echocardiography (TTE) supplemented by transesophageal echocardiography (TEE) has become the most appropriate screening and diagnostic imaging modality for myxomas (and most other cardiac tumors). Mitral valve stenosis can be excluded, and tumor prolapse through the atrioventricular valve may be demonstrated. Tumor prolapse is characteristically evident if echoes are seen behind the anterior leaflet, particularly if they move into the left ventricle during diastole. Echocardiography is invaluable in identifying the precise origin of the myxoma ( Figs. 18-1, 18-2 ).
Computed Tomographic and Magnetic Resonance Imaging
Atrial myxomas and other cardiac tumors can also be identified with computed tomography (CT) or magnetic resonance imaging (MRI), either alone or in combination with echocardiography. Asymptomatic tumors are occasionally identified when CT or MRI scans are performed for other indications.
Cardiac Catheterization and Angiography
Unless other types of cardiac or coronary artery disease require assessment, catheterization and angiography no longer constitute the investigative method of choice. If invasive study is required for suspected left atrial tumors, a selective right heart study is performed by injecting radiopaque media into the pulmonary artery and filming as the dye passes through the left atrium. This method usually gives a clear demonstration of the tumor, whereas selective left ventricular cineangiography often fails to delineate it. For right atrial myxomas, catheter placement into the right atrium is contraindicated, and injection is made into one of the venae cavae.
Natural History
Myxomas occur in older adults and are two to three times more common in women than in men. They are rare in children and have not been described in infants. MacGowan and colleagues estimate the incidence of atrial myxoma to be 0.5 per million population per year. The older literature contains reports of familial myxoma (three restricted to siblings and three with a parent-child relationship). Current knowledge indicates that the natural history of patients with familial myxomas is different from that of patients with nonfamilial, sporadically occurring myxomas (see “Familial versus Nonfamilial Myxoma” under Clinical Features and Diagnostic Criteria earlier in this section).
Myxomas are usually benign, but rarely the tumor metastasizes. Metastases have been reported in brain arteries, sternum, vertebral column, pelvis, scapula, and soft tissues of the back. Metastasis can occur despite benign gross and microscopic appearances, but it is rare. The course of surgically untreated patients with cardiac myxomas is highly variable and cannot be clearly defined. However, once symptoms of dyspnea and hemoptysis develop in the case of left atrial myxomas, or symptoms of abdominal protuberance from ascites or hepatomegaly develop in the case of right atrial myxomas, death usually follows within 1 to 2 years. Little information is available about the frequency of embolization in patients with myxomas, the tendency to repeated embolization if the tumor is not removed, or the course without treatment of patients presenting with constitutional symptoms only.
Technique Of Operation
Single, nonfamilial left atrial myxomas in patients older than about age 50 can simply be excised. Familial myxomas in younger patients should be treated more aggressively. Preparations for operation, median sternotomy, CPB, and myocardial management are the usual ones for adult cardiac surgery (see “ Preparation for Cardiopulmonary Bypass ” in Section III of Chapter 2 and “ Methods of Myocardial Management during Cardiac Surgery ” in Chapter 3 ). Direct caval cannulation is routinely practiced for removal of atrial myxomas. A left atrial vent is not used.
Left Atrial Myxoma
The approach is biatrial. For initial exploration and orientation, the usual incision is made in the left atrium posterior to the interatrial groove ( Fig. 18-3, A ). Blood is removed from the left atrium, and the point of attachment of the tumor to the atrium is determined by inspection ( Fig. 18-3, B ). Assuming it is attached to the atrial septum, which is usually the case, the tumor is not removed from the left atrium. Instead, an oblique right atriotomy is made and the interior of the right atrium examined in case a second tumor is present ( Fig. 18-3, C ). As much as possible of the interior of the right ventricle is also inspected through the tricuspid valve. The atrial septum is then opened with a knife near the center of the fossa ovalis, and a sufficient amount of atrial septum is excised to include the tumor attachment and, if possible, uninvolved tissue 5 mm beyond it. The superior half of the fossa ovalis and adjacent limbus are, if possible, included in the excision, because cells thought to be the precursor of myxoma are more abundant in this area. The tumor is then removed from the heart through the left or right atriotomy, whichever is larger ( Fig. 18-3, D ). Very large tumors may have to be removed piecemeal, although every attempt is made to keep the tumor intact and to avoid tumor embolization. After the tumor is removed, the interior of the left atrium is copiously irrigated with saline solution to evacuate any residual tumor fragments. The defect in the atrial septum is closed either by direct suture or, if too large for this, with a pericardial or synthetic patch ( Fig. 18-3, E ).
If the tumor is attached to the left atrial wall rather than the septum, the zone of attachment is excised, preferably with the full thickness of the adjacent wall, but if this is impracticable, with endocardium and some underlying muscle. The wall defect created can be closed by direct suture or with a patch of autologous or bovine pericardium. The atria are closed and usual precautions against air embolization taken (see “ De-airing the Heart ” in Section III of Chapter 2 ). The rest of the procedure is completed in standard fashion.
Right Atrial Myxoma
Separate left and right atriotomies are not necessary unless there is preoperative evidence of an associated left atrial myxoma. Instead, the right atrium only is opened by the usual oblique incision (see Chapter 30 , Fig. 30-14 ), and after attachments of the tumor are defined, it is excised with the adjacent portion of atrial septum in the manner described in the preceding text. The left atrium is then carefully inspected via the surgically created atrial septal defect. Only if a tumor is seen in the left atrium is that chamber opened by a separate incision. The atrial septal defect is closed as described in the preceding text, and the remainder of the procedure is completed as described.
Other Myxomas
Removal of ventricular myxomas does not require excision of full-thickness ventricular wall, because such a procedure would increase risk and no recurrences have been recorded following less radical removal. Tumors in the left ventricular outflow tract can sometimes be removed via an aortic approach. Otherwise, the approach is through the right atrium for right ventricular tumors and left atrium for left ventricular tumors. The ventricle is opened directly only when the atrial approach is inadequate for tumor removal. The procedure should include careful inspection of the interior of both right and left atria to exclude the presence of additional atrial tumors, which have been found in 15% of patients with right ventricular myxomas.
In those rare instances in which the tumor arises from an atrioventricular valve, the valve usually requires replacement. Also, valve replacement is occasionally required because of leaflet disruption or distortion from the “wrecking ball” action of the tumor (see Fig. 18-2 ). A markedly enlarged atrioventricular valve anulus may require anuloplasty to correct residual valve regurgitation. Such enlargement is particularly likely to occur in the tricuspid valve, because the tricuspid anulus is more easily overstretched by a bulky tumor than is the mitral anulus.
Special Features Of Postoperative Care
Postoperative management is conducted in the usual fashion (see Chapter 5 ).
Results
Survival
Early (Hospital) Death
Hospital mortality after removal of atrial myxomas is less than 5% ( Table 18-2 ). Virtually all deaths are in patients with advanced disability or old age, the mode of death being generally related not to the atrial myxoma but to coexisting cardiac or degenerative disease. Early risks seem somewhat higher after removal of myxomas from the ventricular cavities. Among 32 patients who underwent removal of right ventricular myxoma, there were three hospital deaths (9%; CL 4%-18%), and among 14 patients in whom a left ventricular myxoma was removed, there were three hospital deaths (21%; CL 10%-38%).
Table 18-2
Results of Operation for Removal of Cardiac Myxomas a
| LA | RA | Biatrial | RV | LV | Total | |
|---|---|---|---|---|---|---|
| Bhan et al. | 55 (2) | 10 (0) | 1 (0) | 0 | 0 | 66 (2) |
| Bjessmo and Ivert b | 56 (1) | 6 (0) | 1 (0) | 0 | 0 | 63 (1) |
| Bortolotti et al. | 46 (2) | 6 (0) | 0 | 2 (0) | 0 | 54 (2) |
| Centofanti et al. | 77 (3) | 6 (0) | 0 | 0 | 0 | 83 (3) |
| Jones et al. | 17 (0) | 3 (0) | 0 | 0 | 0 | 20 (0) |
| MacGowan et al. | 24 (0) | 0 | 2 (0) | 0 | 0 | 26 (0) |
| Meyns et al. | 31 (1) | 0 | 0 | 1 (0) | 0 | 32 (1) |
| Murphy et al. | 57 (2) | 6 (0) | 0 | 0 | 0 | 63 (2) |
| T otal | 363 (11) | 37 (0) | 4 (0) | 3 (0) | 0 | 407 (11) |
| [3.0%] | [0%] | [0%] | [0%] | [2.7%; CL 1.9%-3.8%] |
Key: CL, 70% confidence limits; LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.
a Number of patients dying in hospital is in parentheses.
b Includes Crafoord's case, the first successful procedure worldwide.
Time-Related Survival
Death after hospital discharge is uncommon, but recurrence of the myxoma (see “ Recurrence ” later in this section) can lead to fatal complications. Most other late deaths are from causes other than the cardiac tumor. Excellent long-term results have been reported in a number of studies ( Fig. 18-4 ). Presumably, these contained only patients with nonfamilial myxomas. Too few patients with familial myxomas have been reported for adequate assessment of long-term survival. Presumably, their survival is considerably worse than that of those with nonfamilial myxomas. Premature late death may occur more commonly when prosthetic valve replacement is necessary at time of myxoma removal because of complications from the prosthesis.
Recurrence
What has been classified as recurrence can be due to (1) tumor implantation (seeding at the time of removal), (2) incomplete removal, or (3) growth from a new focus (multicentric origin). Recurrence of a “sporadic” myxoma is unusual, occurring in only about 1% to 3% of patients, and myxomas with a normal ploidy rarely recur. In contrast, 30% to 75% of patients with familial myxomas experience recurrence. When the tumor exhibits an abnormal ploidy, 40% of patients experience recurrence. A first recurrence is often followed by a second, and recurrence may be in a cardiac chamber that was not the site of the original tumor. Recurrences may become apparent as early as 6 months and as late as 11 years after excision, but the average is about 30 months after removal of the first myxoma. At least one patient has experienced recurrence of a left ventricular myxoma; it involved the aortic valve and necessitated valve replacement.
Postoperative Arrhythmias
Atrial arrhythmias are common after removal of atrial myxomas. Conduction disturbances are also reported and may be related to failure to limit resection to safe areas of the atrial septum or wall.
Functional Status
Living patients are generally in good health unless they have other disease processes or residual effects from a preoperative embolic event.
Indications For Operation
Surgical removal is indicated whenever diagnosis of cardiac myxoma is made. Historically, it was considered an urgent procedure, particularly if the patient had a history of embolism or syncope, because it had been noted that 8% to 10% of patients died of embolic complications while awaiting operation. However, more recent experience suggests that elective operation (as opposed to urgent) has resulted in no greater mortality or morbidity.
Special Situations And Controversies
Yu and colleagues in China have reported totally thorascopic surgical resection, often left atrial and two right atrial myxomas, using peripheral cannulation for CPB.
Section II
Papillary Fibroelastoma
Definition
Papillary fibroelastomas are benign tumors representing less than 10% of all cardiac tumors, and they are important because, like myxomas, they are a curable and identifiable cause of strokes and other embolic events.
Morphology
Papillary fibroelastomas are usually small tumors but may extensively involve structures such as the mitral valve. They have characteristic papillary fronds, which can be recognized grossly ( Fig. 18-5 ). At times they have been thought to be myxomas, but their histologic appearance is diagnostic. The fronds have a central core of dense connective tissue sometimes lined by hyperplastic endocardial tissue. They have been said to resemble normal chordae tendineae.
Papillary fibroelastomas usually develop on a valve leaflet, most commonly an aortic cusp or mitral leaflet. Less commonly, they appear on the tricuspid valve and ventricular septum, or rarely, on the aortic wall.
Clinical Features And Diagnostic Criteria
This uncommon tumor rarely appears to cause trouble at its site of origin. More often, it is responsible for embolization, either by detachment and embolization of one or more of its fronds or by inciting thrombus formation on its surface, with subsequent thromboembolism. Reported sites of embolism include primarily the brain and coronary arteries. They have also been observed in the lungs and retinal arteries. Diagnosis in all living patients has been made by echocardiography and most accurately by TTE and TEE with Doppler color flow interrogation. Characteristically, by echocardiographic interrogation the tumor is small (about 1 cm 2 ), usually pedunculated and mobile, with a homogenous speckled pattern and stippling along its edges ( Fig. 18-6 ).
Natural History
Little is known about the natural history of papillary fibroelastomas of the heart, except that they tend to produce emboli. Embolization is the presumed mechanism of sudden death in some patients.
Technique Of Operation
Preserving the involved valve is possible in most patients when the tumor is small. Monitoring the repair by intraoperative TEE is important. The only choice for treatment of multicentric extensive papillary fibroelastomas is valve replacement.
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