Rupture of true lateral left ventricular aneurysm sparing mitral apparatus; A case report

Abstract

Introduction and importance

True postero-lateral ventricular aneurysm occurring in the submitral position is a rare entity and is usually of congenital etiology. Large aneurysms strongly alter cardiac geometry and impair cardiac systolic and diastolic function, resulting in various complications.

Case presentation

We report a case presenting with cardiogenic shock due to the rupture of a large postero-lateral LV aneurysm, successfully managed by emergent surgery and aneurysmectomy. The preoperative trans-thoracic echocardiographic evaluation showed a large size pericardial effusion with large submitral round aneurysm with a thin wall along the postero-lateral border of the LV. The patient was scheduled for emergent operation with high suspicion of post MI lateral free wall rupture and tamponade.

Clinical discussion

The presented case is very interesting regarding challenge of diagnosis and successful surgical intervention as to date very rare cases of true posterolateral LV aneurysm rupture have been reported in the literature.

Conclusion

Coronary angiography and pathologic examination in this case revealed that the etiology of the patient's posterolateral LV aneurysm might be a silent myocardial infarction in LCX territory, although a less common congenital origin cannot be ruled out completely.

Highlights

• •This case highlights the importance of imaging and careful surgical planning in managing rare, anatomically distinct LV aneurysm ruptures, especially when classic complications are unexpectedly absent.

List of abbreviations

LV

Left ventricule

MI

Myocardial infarction

ECG

Electrocardiogram

LVEF

Left ventricular ejection fraction

RCA

Right coronary artery

LAD

Left anterior descending

LCX

Left circumflex artery

TEE

Trans-esophageal echocardiography

MRI

Magnetic resonance imaging

CT

Cardiac computed tomography

CPB

Cardiopulmonary bypass

• •A case presenting with cardiogenic shock due to rupture of a large posterolateral true left ventricular aneurysm, initially suspected as post-myocardial infarction free wall rupture, —a rare presentation with detailed surgical nuances and favorable long-term outcome.
• •Emergent surgical repair was performed. The aneurysm was carefully dissected and partially resected while preserving the mitral and submitral apparatus. The lateral location and mitral sparing allowed for targeted surgical repair and preserved valvular function, setting this case apart from most post-infarct ruptures which often lead to catastrophic mitral regurgitation or require valve intervention.

1. Introduction

True left ventricular (LV) aneurysms, naturally composed of a scarred, thin and fibrotic akinetic or dyskinetic myocardial wall, which are most commonly a late result of transmural myocardial infarction (MI) [1]. Postero-lateral ventricular aneurysms occurring in the submitral position on the lateral left ventricular wall between anterior and posterior papillary muscles is a very uncommon entity and those leaving the mitral valve apparatus intact are particularly rare. They represent less than 1 % of ventricular aneurysms and are usually of congenital etiology although other causes such as ischemic heart disease may be the preceding etiology [2].

Clinical presentations of ventricular aneurysms are varied depending on location, size, ventricular function and valvular involvement. Large aneurysms strongly alter cardiac geometry and impair cardiac systolic and diastolic function, resulting in heart failure symptoms, coronary insufficiency due to compressive effect, potentially lethal rupture or arrhythmias, thrombus formation and systemic embolic events [3].

Although etiology, presentation and natural history of true ventricular aneurysms are different from LV pseudoaneurysm, sometimes the accurate diagnosis of these two conditions is challenging [4]. We report a case presenting with cardiogenic shock due to the rupture of a large posterolateral LV aneurysm initially misdiagnosed as post-MI free wall rupture managed by emergent surgery and aneurysmectomy at our institution.

2. Case presentation

This work has been reported in line with the SCARE criteria [5]. A 65-year-old Caucasian male patient presented to the emergency department with cardiogenic shock. His symptoms began gradually two days prior to admission, starting with dizziness and shortness of breath. At arrival, his vital signs were notable for a systolic blood pressure of 65 mmHg, a heart rate of 115 bpm, a temperature of 37.1 °C, and a respiratory rate of 23 breaths per minute.

The patient had no history of drug use, tobacco or alcohol consumption, hypertension, or diabetes. Initial electrocardiogram (ECG) showed a postero-lateral myocardial infarction (MI).

Preoperative transthoracic echocardiography (TTE) revealed a large pericardial effusion with a sizable submitral round aneurysm (8 × 6 cm) characterized by a thin wall along the posterolateral border of the left ventricle (LV) (Fig. 1). The mitral valve showed mild insufficiency, and the left ventricular ejection fraction (LVEF) was reduced to 35 %. Coronary angiography was performed immediately following patient resuscitation. Findings included right coronary artery (RCA) dominance with normal flow in the RCA and left anterior descending (LAD) arteries. The left circumflex artery (LCX) was rudimentary and totally occluded proximally without retrograde filling.

Fig. 1.

Transthoracic echocardiography: apical four-chamber view showing a large aneurysm in the lateral wall of the left ventricle (LV), the neck of the aneurysm (blue arrowhead) and clot in the cavity of the aneurysm (white arrowhead). LA: left atrium; LV: left ventricle; RA; right atrium; RV: right ventricle. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

The patient was scheduled for emergent surgery under high suspicion of post-MI free wall rupture and cardiac tamponade. After median sternotomy and pericardiotomy, bloody tamponade was encountered. Cardiopulmonary bypass (CPB) was promptly established with central cannulation under systemic heparinization. The heart was arrested using cardioplegia, and the true aneurysm located along the posterolateral LV wall was carefully exposed.

Precise dissection was performed to delineate the aneurysm boundaries while meticulously preserving the mitral valve apparatus, including papillary muscles, chordae tendineae, and mitral leaflets. Extreme care was taken to avoid traction or injury to these subvalvular structures, which are critical for maintaining mitral competence and LV function.

The thin-wall of true aneurysm sac was partially resected, cleansed from thrombi and its limbus was sown together with 4/0 prolene taking care to spare the mitral and submitral apparatus, maintaining a rim of healthy myocardium adjacent to the mitral and its supporting structures. Reinforcement with pledgets or Teflon strips was not required owing to adequate tissue quality. Throughout the procedure, particular attention was given to maintaining left ventricular geometry and function while preventing mitral valve dysfunction. Intraoperative evaluation confirmed intact mitral valve function without significant regurgitation (Fig. 2, Fig. 3). The patient weaned from CPB easily after cardiac de-airing.

Fig. 2.

Intra-operative photo showing the base (lower arrow) and ruptured nipple (upper arrow) of submitral LV aneurysm.

Fig. 3.

True LV aneurysm was resected and repaired taking care to spare the mitral and submitral apparatus intact.

Pathological examination of the resected tissue confirmed the diagnosis of a true aneurysm. The postoperative course was uneventful, and the patient was discharged on postoperative day 5 with warfarin therapy.

Postoperative echocardiography showed an improved left ventricular function with mild systolic dysfunction (LVEF = 45 %) and mild mitral valve regurgitation. On follow-up echocardiography 6 months after discharge, LVEF and mitral regurgitation severity remained stable (LVEF 45–50 %). The patient reported no limitations in physical activity and was classified as New York Heart Association (NYHA) functional class I. Furthermore, the patient had no problems in his daily work after 1.5 years of follow-up, with no complications reported. His quality of life had significantly improved by 3 months post-surgery.

3. Discussion

Ventricular aneurysms are most often located in the apex (31.7 %), the inferior wall (23.8 %), and the anterior wall (9.5 %), most commonly related to LAD occlusion, but only less than 1 % of ventricular aneurysms involve the lateral LV wall and tend to be remarkably small-sized [2,6].

Most often, postero-lateral ventricular aneurysms are of congenital etiology, but other alternative causes include: infections, such as, endocarditis and tuberculosis; inflammatory processes such as Takayasu disease and rheumatic fever; neoplasia and post infarction myocardial injury [2].

Transthoracic echocardiography is the initial diagnostic tool for evaluation of LV aneurysm and its type but may be unrevealing, since in suspected cases, other modalities such as TEE, angiography, cardiac magnetic resonance imaging (MRI) and cardiac computed tomography (CT), will have a higher diagnostic accuracy [4]. In two studies, an orifice-to-pseudoaneurysm diameter ratio of 0.5 in echocardiographic study was applied to differentiate patients with pseudoaneurysm from those with true ventricular aneurysms [7,8]. Pseudoaneurysm is connected to ventricle with a small, narrow-necked channel forming a large sac containing clot without any myocardial elements [9]. Despite of advances in preoperative imaging, pathologic examination of tissue layers of aneurysm wall remains the gold standard of diagnosis.

True aneurysm, generally, calls for an elective surgery to prevent previously mentioned complications and to improve cardiac function by restoring LV geometry. Patients presenting with rupture of true or pseudoaneurysms mandate emergent surgical intervention regardless of initial diagnosis. In our presented case we initially suspected that the patient had possibly a recent and silent myocardial infarction in the territory of the left circumflex artery as the infarct-related coronary artery, complicated by lateral free wall rupture and pseudoaneurysm formation. Emergent surgical exploration revealed a rupture of true aneurysm in the rare position of posterolateral LV wall which confirmed by pathologic examination.

4. Conclusion

Our reported case is very interesting regarding challenge of diagnosis and successful surgical intervention as to date very rare cases of true posterolateral LV aneurysm rupture have been reported in the literature. Coronary angiography and pathologic examination in this case revealed that the etiology of the patient's posterolateral LV aneurysm might be a silent myocardial infarction in LCX territory, although a less common congenital origin cannot be ruled out completely.

Authors' contributions

Dr. M.K. performed operation and approved the final version. Dr. L.B. prepared the first draft of the manuscript, analyzed the echocardiographic views, and read and approved the final version of the manuscript. Dr. F.K. wrote the first manuscript and read and approved the final version of the manuscript.

Consent

Written informed consent was obtained from the patient for publication and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

This study is a case report and it was not included in the ethical committee of Mashhad University of Medical Sciences. However, ethical issues were considered in the publication and consent from patient to publish data anonymously according to ethical guideline of Mashhad University of Medical Sciences.

Guarantor

Dr. Bigdelu.

Funding

There is no funding support.

Declaration of competing interest

The authors declare that they have no competing interests.

Data availability

Not applicable.