Multiple Left Ventricular Thrombi in a Patient with Left Ventricular Noncompaction

Abstract

The major clinical features of myocardial noncompaction are heart failure, arrhythmias, and thromboembolic events. Prominent myocardial trabeculae and deep recesses characteristic of myocardial noncompaction can cause stagnant blood flow and the formation of left ventricular clots. We describe the case of a 62-year-old woman who presented with symptoms of heart failure secondary to left ventricular noncompaction. Transthoracic and transesophageal echocardiography revealed multiple left ventricular thrombi, which had formed despite the patient's long-term therapy with aspirin.

Anticoagulative therapy should be considered for patients with myocardial noncompaction who also have risk factors for thromboembolism, such as atrial fibrillation, a history of systemic embolism, or severe left ventricular systolic dysfunction. However, chronic antiplatelet therapy may not sufficiently prevent clot formation in patients who have myocardial noncompaction and severe left ventricular systolic dysfunction.

Myocardial noncompaction, a rare congenital cardiomyopathy, has been identified in up to 0.24% of patients who have undergone echocardiography examination.¹ Myocardial noncompaction usually affects the left ventricle (LV) and is characterized by prominent trabeculae, deep endocardial recesses, and a sponge-like appearance of the myocardium.^2,3 The condition can be asymptomatic and undetected, or it can present in patients of any age as severe heart failure, ventricular arrhythmias, or thromboembolism.^1,2 We describe the case of a woman who presented with symptoms of heart failure secondary to LV noncompaction. Echocar-diographic examination revealed multiple LV thrombi, which had formed despite the patient's long-term therapy with aspirin. We discuss imaging and therapeutic considerations in patients with myocardial noncompaction and LV systolic dysfunction.

Case Report

A 62-year-old woman with the presumptive diagnosis of idiopathic dilated cardiomy-opathy (New York Heart Association functional class II) presented at our institution with decompensated heart failure, general weakness, and a disoriented mental state that had continued for 10 days. She had no chest pain, palpitations, or syncope, and she had no congenital cardiac anomaly or family history of myocardial noncompaction or cardiomyopathy. Her medications included aspirin (325 mg/d), lisinopril (10 mg/d), furosemide (40 mg/d), and metoprolol (50 mg/d). Upon presentation, she was hypotensive (blood pressure, 86/58 mmHg) and tachycardic (heart rate, 115 beats/min), but in sinus rhythm. Auscultation revealed bilateral crackles in the lowerlung fields. A chest radiograph showed moderate cardiomegaly and pulmonary vascular congestion. Transthoracic echocardiograms (TTE) (Figs. 1 and 2) and a transesophageal echocardiogram (TEE) (Fig. 3) showed a hypertrabeculated, sponge-like appearance of the myocardium that involved the apical, inferior apical, and septal segments of the LV. The patient's LV systolic ejection fraction was 0.20 to 0.25. A color-flow Doppler echocardiogram revealed blood flow in deep intertrabecular recesses (Fig. 4). Two mobile, homogeneous, echodense structures were identified in the LV: one in the basal septum (dimensions, 1.2 × 1.4 cm) and the other in the apicolateral noncompacted segment (dimensions, 1.1 × 3.4 cm) (Fig. 5). Transthoracic echocardiograms revealed 4 additional mobile, echodense structures, possibly thrombi, between the deep myocardial recesses (Fig. 6). The patient was started on warfarin and enoxaparin; however, her clinical condition deteriorated rapidly. Despite no neurologic evidence of systemic embolization during her hospitalization, she soon died of multiorgan failure. No autopsy was performed.

Fig. 1 Two-dimensional transthoracic echocardiograms show a hypertrabeculated, sponge-like appearance of the left ventricle in A) apical 3-chamber view and B) zoomed apical 3-chamber view.

Fig. 2 Two-dimensional transthoracic echocardiogram (apical long-axis view) shows a hypertrabeculated left ventricular myocardium.

Real-time motion image is available at www.texasheart.org/journal.

Fig. 3 Transesophageal echocardiogram shows a hypertrabeculated, sponge-like appearance of the left ventricle.

Fig. 4 Color-flow Doppler echocardiogram shows blood flow between the hypertrabeculated segments.

Fig. 5 Transthoracic echocardiograms of the left ventricle show mobile, homogeneous echodense structures (arrows), possibly thrombi, in the A) basal septum and B) apicolateral noncom-pacted segment.

Real-time motion image of Figure 5A is available at www.texasheart.org/journal.

Fig. 6 Transesophageal echocardiograms show multiple echodense structures (arrows) in the left ventricle between the deep myocardial recesses in A) short-axis view at 0° and B) transgastric view at 106°.

Real-time motion images are available at www.texasheart.org/journal.

Discussion

Thromboembolic events occur in 21% to 38% of patients with myocardial noncompaction. Brain, lung, and mesenteric organ tissue can be involved.^2,4 In patients with LV systolic dysfunction or intra-atrial clot formation—particularly if such patients also have atrial fibrillation—embolic events can result from a de novo thrombus in LV trabeculae.⁵ Prominent myocardial trabeculae and deep recesses cause stagnant blood flow, which can result in the formation of clots in the LV. Our patient presented with symptoms of heart failure secondary to LV noncompaction and had multiple LV thrombi, despite long-term therapy with aspirin.

In patients with LV noncompaction, thrombi are usually detected by 2-dimensional TTE or TEE; 3-dimensional echocardiography is a useful supplemental diagnostic tool.⁶ However, as with the patient whose case we describe here, we have found that confirming LV noncompaction echocardiographically can be difficult—the diagnosis can frequently be overlooked when most of the pathologic segments are in the apex.⁷ When echocardiographic findings are inconclusive, cardiac magnetic resonance imaging (CMR) can be used to identify noncompacted segments and intratrabecular thrombi. The diagnostic value of CMR is excellent in all noncompaction cases, whether or not there are intraventricular thrombi; however, because of the limited availability of CMR, 2-dimensional TTE is still the gold standard of diagnostic methods. Furthermore, the use of echocardiography: contrast agents improves the diagnostic accuracy of TTE, especially if findings are otherwise inconclusive.⁷ No large-scale study has been conducted to compare CMR with high-quality contrast TTE in the diagnosis of myocardial noncompaction.

In a study of 229 patients with noncompaction and sinus rhythm, Fazio and colleagues⁸ reported a low prevalence of stroke (n=4) and echocardiographically detected LV thrombus (n=1); 50% of the study patients had LV systolic dysfunction. Because of the low risk of stroke and embolic events, the authors concluded that oral anticoagulative therapy was not indicated solely for the noncompaction. Although we agree that routine anticoagulative therapy for all patients with noncompaction is not a reasonable recommendation, we believe that long-term anticoagulation should be considered for patients who also have risk factors for thromboembolism, such as atrial fibrillation, a history of systemic embolism, or severe LV systolic dysfunction. Clopidogrel could be an appropriate alternative agent for patients who are not candidates for systemic anticoagulation. In our experience, the incidence of LV thrombus in cases of noncompaction is low. End-stage heart failure in our patient might have increased the risk of in situ thrombosis. Nonetheless, we think that chronic antiplatelet therapy with aspirin may not sufficiently prevent the formation of thrombi in patients who have noncompaction and severe LV systolic dysfunction. For such patients, clinicians should consider long-term oral anticoagulation with warfarin or a direct thrombin inhibitor, such as dabigatran. Patients who cannot take oral anticoagulants should be given stronger antiplatelet therapy, including clopidogrel with or without aspirin.

Acknowledgment

We are grateful to Nicole Stancel, PhD, of the Texas Heart Institute at St. Luke's Episcopal Hospital, for editorial assistance with the manuscript.