Repair of left ventricular aneurysm in the setting of noncompaction

Abstract

Although left ventricular (LV) aneurysm is a well-described complication of ischemic heart disease, it may less frequently develop in the setting of normal coronary anatomy and myocardial blood supply. LV noncompaction (LVNC) is a particularly rare etiology of LV aneurysm; in the few cases previously reported in the literature, non-surgical management was pursued. In this report, we discuss the surgical repair of an ‘idiopathic’ LV aneurysm in a patient who presented with multiple thromboembolic events, with LVNC as the likely etiology on the underlying LV pathology.

<Learning objective: Left ventricular (LV) noncompaction represents a rare etiology of LV aneurysm; although non-surgical management of this condition has been previously reported, we demonstrate that early surgical intervention is an acceptable treatment option.>

Introduction

Left ventricular (LV) aneurysms are well-described potential complications of chronic myocardial ischemia and/or infarction. Non-ischemic etiologies of LV aneurysm, although rare, encompass a spectrum of infectious, inflammatory, and/or congenital disease processes [1,2]. LV noncompaction (LVNC) is a particularly rare cause of ventricular aneurysm, with only a few cases reported in the literature to date [3,4]. We herein discuss the clinical presentation of a patient with an ‘idiopathic’ LV aneurysm, likely secondary to LVNC, and its subsequent surgical repair.

This study was deemed exempt from Institutional Review Board approval given the nature of the case study. Informed consent for the writing and publication of this report was obtained from the patient.

Case report

A 46-year-old man with a history of paroxysmal atrial fibrillation, therapeutically anticoagulated with apixaban, and multiple prior cerebrovascular accidents (CVA) presented with new-onset right hemiparesis. Acute occlusion of the left internal carotid artery was identified, and the patient underwent successful transcatheter thrombectomy with complete resolution of his neurological deficit. It was suspected that the CVA was embolic in nature; thus, cardiac workup was pursued. During his hospital admission, a transesophageal echocardiogram (TEE) was notable for significantly diminished LV systolic function (estimated ejection fraction 35%), marked thickness and hypertrophy of the papillary muscles, and an echogenic apically located mass in the LV, which was suspicious for thrombus (Fig. 1a). There was no thrombus identified in the left atrial appendage, and a hematologic panel to discern systemic hypercoagulability was unremarkable.

Fig. 1.

Pre-operative imaging. (a) Transesophageal echocardiogram revealing aneurysmal dilation of the left ventricle, severe papillary muscle thickening, and left ventricular thrombus (white arrow); (b) coronary angiography demonstrating normal left coronary anatomy without significant stenosis; (c,d) Computed tomography angiography of the chest demonstrating an enlarged left ventricle with a wide-based aneurysm near the left ventricular apex, thickened papillary muscles, and prominent trabeculations in both ventricles (white arrow).

The patient reported no history of prior myocardial infarction or anginal symptoms. He had no other known medical comorbidities. He quit smoking 15 years ago, prior to which he smoked only socially. He reported no family history of coronary artery disease.

The patient was started on a heparin drip and transferred to our institution for cardiac surgical evaluation. Computed tomography (CT) angiography demonstrated a wide-based true aneurysm involving the anterior wall of the left ventricle near its apex, with no definite intraventricular mass identified. Prominent trabeculations were noted in both ventricles (Fig. 1c,d). Transthoracic echocardiogram confirmed resolution of LV thrombus. The patient's coronary arteries were normal and free of atheromatous disease, both on CT angiography and at catheter-based coronary angiogram (Fig. 1b).

Despite resolution of the LV thrombus after continued anticoagulation using unfractionated heparin, it was deemed appropriate to surgically repair the LV aneurysm in light of the patient's reduced ejection fraction and history of multiple prior neurological events, all of which were presumed to be embolic in etiology.

Intraoperative examination revealed the LV apex to be largely replaced by a large true, thin-walled aneurysm. In a small portion of the aneurysm, the tissue was almost translucent, in an apparent pre-rupture stage. The aneurysm was opened, and multiple thickened ventricular trabeculae, as well as deep intra-trabecular recesses, were observed. These trabeculae were resected and sent for pathologic evaluation, with care taken to preserve LV geometry and function (Fig. 2). The aneurysmal portion of the LV was excluded using a prosthetic patch, and the sac was closed over the patch with a running prolene suture, buttressed by polytetrafluoroethylene felt. The left atrial appendage was occluded during the same procedure in view of the history of atrial fibrillation. The ventricular myocardium that remained following aneurysm exclusion and trabeculae excision was, on gross appearance, normal. Intraoperative transesophageal echocardiogram revealed absence of wall-motion abnormalities and normal systolic and diastolic function following separation from cardiopulmonary bypass, with an immediate improvement in ejection fraction from 35 to 45%.

Fig. 2.

Intraoperative examination of left ventricular aneurysm, demonstrating (a) significant dilation and thinning of the apex of the left ventricle (black arrow) and (b) prominent intraventricular trabeculae (white arrow).

Histological examination of the excised trabeculations revealed myxoid degeneration of myocardial tissue without inflammatory changes; this was noted to be highly suggestive of LVNC.

The patient's postoperative course was unremarkable, and he was discharged home with instructions to continue apixaban anticoagulation. While planned postoperative CT and magnetic resonance imaging was not obtained, the patient presented to an outside emergency room three months post-operatively with dyspnea and was worked up for suspected pulmonary embolism; CT angiography obtained revealed appropriate repair of LV aneurysm and absence of filling defects (Fig. 3). On eight-month follow-up transthoracic echocardiogram, the recovery in myocardial function was found to be sustained, with an ejection fraction of 60%, a LV end systolic diameter of 3.3 cm, and a LV end diastolic diameter of 5.5 cm.

Fig. 3.

Computed tomography scan with contrast timed for opacification of pulmonary arteries in a pulmonary embolism workup three months postoperatively, revealing absence of aneurysm and filling defects in both (a) sagittal and (b) axial views.

Discussion

LV aneurysm associated with a non-ischemic etiology is a rare phenomenon. Previously described causes include congenital wall abnormalities, hypertrophic cardiomyopathy, myocarditis, tuberculosis, trypanosomiasis, sarcoidosis, glycogen storage diseases, and trauma [1,2]. Among the congenital wall abnormalities associated with aneurysm formation, LVNC is, itself, uncommon [3,4]. LVNC is the consequence of failure of compaction of the highly trabeculated fetal myocardium, which results in numerous prominent ventricular trabeculations with deep intertrabecular recesses [5]. The clinical course of LVNC can be highly variable, although the more common presenting symptoms include congestive heart failure secondary to LV systolic dysfunction, arrhythmias, or thromboembolic phenomena. Management of LVNC is most frequently medical, and its aim is to control presenting symptoms and prevent complications of arrythmia and thromboembolism.

The development of an LV aneurysm in the setting of LNVC is particularly infrequent, having been originally described by Sato and colleagues in 2005, in their report of a 66-year-old woman who presented with LV failure and ventricular tachycardia [3]. Yakabe and colleagues reported the case of a 44-year-old man who presented with congestive heart failure and multiple embolic events, secondary to LV aneurysm and LVNC [4]. In contrast to our patient, non-surgical management was pursued in each of these cases. While formal diagnostic imaging criteria for LVNC were not necessarily met in our patient, including a maximal end-systolic ratio of non-compacted to compacted myocardium >2:1, the presence of prominent trabeculations with deep intertrabecular recesses on CT angiography was nevertheless suspicious for the diagnosis [6]. This suspicion was strongly supported by gross intraoperative examination, revealing quite prominent and thickened trabeculations, with deep recesses contributing to a severely thinned portion of myocardium. Moreover, the pathologic findings of myxoid degeneration without inflammatory changes noted in the excised trabeculae is consistent with prior reports of histopathologic evaluation in LVNC [5].

The presenting symptoms of LV aneurysm tend to vary greatly between case series, although systemic thromboembolism remains relatively uncommon, occurring in approximately 5% of patients [2]. Interestingly, it has been suggested that the presence of an extensively trabeculated ventricle, as was observed in our patient, may increase predisposition to thromboembolism [4]. While systemic anticoagulation alone may be appropriate in some cases of LV aneurysm complicated by thrombus, surgical aneurysmectomy represents the most definitive management approach, regardless of etiology [4]. The goal of surgical intervention in our patient included complete exclusion of akinetic myocardium to prevent recurrent thrombus formation, reinforcement of weakened myocardium, and restoration of LV geometry with preserved mitral valve competency. It was achieved with excellent results and an immediate improvement in EF on intraoperative TEE, from 35 to 45%, with resolution of apical akinesis in the region of the excluded aneurysm.

Conclusion

Our case describes a rare non-ischemic LV aneurysm, with LVNC as the likely etiology, presenting with multiple systemic thromboembolic phenomena. Although non-surgical management of this condition has been previously reported, we elected to undertake definitive surgical repair.

Declarations

Ethics Approval: Institutional Review Board approval waived due to nature of case report.

Consent for Publication: Verbal informed consent for the writing and publication of this report was obtained from the patient. Consent is documented internally.

Availability of Data and Materials: No data are available for sharing in this study.

Competing Interests: The authors have no conflicts or competing interests to disclose.

Funding: No funding was provided for the preparation of this paper.

Authors’ Contributions: All authors contributed to the case review, drafting, and editing of this manuscript.

IRB approval

IRB approval not needed due to nature of case report.

Declaration of Competing Interest

The authors have no disclosures.