Acquired ventricular septal defect secondary to aortic valve endocarditis

Abstract

Infective endocarditis remains a deadly disease with a significant mortality rate. While ventricular septal defects (VSDs) have been linked to an increased risk of infective endocarditis, cases of acquired VSDs resulting from infective endocarditis are not well-documented in the literature. Our report highlights a rare case of acquired VSD that resulted directly from aortic valve endocarditis, treated with successful repair and placement of permanent pacemaker.

Introduction

With a rising incidence in the United States infective endocarditis remains a deadly disease with a mortality rate ranging from 17 to 36% [1]. Although congenital ventricular septal defects (VSDs) and congenital heart defects have been linked to an increased risk of infective endocarditis [2], cases of acquired VSDs due to erosion through the myocardial tissue from infective endocarditis are not well-documented in the literature [3]. We present a case of an adult in the U.S. with native aortic valve gram-positive staphylococci and streptococcus anginosus endocarditis resulting in a large acquired VSD. The condition was successfully diagnosed and treated with surgery. This case also highlights a successful treatment of postoperative complete heart block with permanent pacemaker placement.

Case presentation

A 57-year-old male patient with a known history of Hodgkin’s Lymphoma status post chemotherapy and chest radiation in 2008, alcohol use disorder, and chronic tobacco use presented to an outside hospital with chest pain, shortness of breath, night sweats, and low-grade fevers, for the past 7 days. During the physical examination, a murmur was heard over the left sternal border. Additionally, poor dentition with several missing teeth was noted. The patient met the criteria for systemic inflammatory response syndrome. Blood cultures detected gram-positive staphylococci and streptococcus anginous. Initial physical findings showed signs of congestive heart failure. Due to pressing concern for potential endocarditis, transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE) were performed. Results showed aortic regurgitation, stenosis, and a mobile vegetation on the ventricular side of the valve that extended into the outflow tract. The patient was managed with antibiotics until transfer to a tertiary center.

Upon arrival, an updated echocardiogram additionally revealed a large VSD that demonstrated left-to-right flow into the right ventricle (Fig. 1). Due to the risk of cardiac decompensation and septic embolization, and size of the vegetation an immediate surgical intervention was deemed necessary. The patient underwent a median sternotomy, and the pericardium was opened. Catheter placement into right coronary sinus was unobtainable, despite trial of multiple sizes in catheters, due to stenoses shortly after the origin of the coronary sinus. Thus, cardioplegia was given directly down the coronary ostia. The first dose of cardioplegia was given anterograde with compression of the ventricle so bleeds would go down the coronary arteries. Topical cooling was also utilized along with bypass. On cardiopulmonary bypass, the aorta was opened, and the diseased aortic valve was excised. Primarily the right aortic and non-coronary cusps were involved. The necrotic ventricular septum was visualized and a VSD, approximately the size of a 21 mm valve sizer was identified (Fig. 2). A bovine patch was used to close the VSD (Fig. 3). The patch was sutured continuously through the annulus to close the VSD prior to placing the prosthetic valve. Following complete debridement and removal of all calcium, a mechanical aortic valve was placed and secured in an annular position. Sutures were placed circumferentially through the annulus and patch to seat the prosthetic valve. Patient was weaned off cardiopulmonary bypass and chest was closed. Cross-clamp time was 94 min. Bypass time was 122 min with catheters placed in the ascending aorta for administration of cardioplegia and venting. Three days following the procedure, the patient developed complete heart block, a known complication of VSD repair [4] and a permanent pacemaker was placed. The patient tolerated the surgery and procedure well and was discharged on post operative day 14. He followed up in clinic two weeks later and reported significant improvement in his symptoms. Per infectious disease, the patient received 10 weeks of IV Rocephin via PICC line. He then was placed on penicillin V potassium (PEN VK) 500 mg by mouth 2x daily for chronic suppressive therapy. The most recent echocardiogram, one month post-operatively, indicated a properly functioning mechanical aortic valve, a mildly dilated left ventricle, ejection fraction of 55–60% and a 2 mm dehiscence of the patch.

Fig. 1

Echocardiogram demonstrated VSD with left-to-right flow

Fig. 2

The aortic valve has been excised, and the VSD is visible

Fig. 3

Bovine patch placed to repair VSD

Discussion

The primary complications of infective endocarditis result from direct damage to cardiac tissue and function. Damage to cardiac valves may result in regurgitation, defective valve leaflets, myocardial abscesses and fistulas. Hemodynamic compromise often leads to the acute onset of heart failure, which is the leading cause of death in infective endocarditis cases [1]. Distant complications, such as septic emboli, metastatic infection, and immunologic phenomena can also complicate infective endocarditis [1].

In our case the VSD likely developed from bacterial erosion through the interventricular septum. There are only a few documented cases of this in literature. Durden et al. described a case of a pediatric patient who had a known bicuspid aortic valve and aortic stenosis who developed Staphylococcus aureus endocarditis on the aortic and tricuspid valves. Subsequent exams discovered a new VSD that was repaired with a bovine patch [5]. Darabant et al. discusses an acquired VSD in the setting of culture negative aortic valve endocarditis from a severe aortic regurgitation jet [6]. A second adult case by De Caluwé et al. describes an acquired VSD occurring in the setting of an aortic root abscess from a mechanical aortic valve [7]. Finally, Ishiekwene el al. describes aortic and mitral valve endocarditis, left ventricular outflow tract septal abscess and VSD formation [8].

Our case is unique in that he had a native aortic valve and no pre-existing VSD. Our hypothesis is that the patient’s poor dental hygiene and subsequent transient bacteremia likely lead to aortic valve endocarditis and formation of VSD [9]. On initial TEE imaging, the ventricular septal defect was not seen, and as the disease progressed it was eventually seen on TEE at the center where he underwent surgical repair. This case represents successful surgical management with removal of necrotic tissue, VSD repair and aortic valve replacement. Additionally, the patient did have a history of Hodgkin’s lymphoma with last chemotherapy and radiation treatment in 2008. We did hypothesize that chemotherapy and radiation played a role in weakening the cardiac tissue to VSD, however there was no prior echocardiogram to support this hypothesis.

The case is also unique because after surgical repair he developed a complete heart block that required a permanent pacemaker implant. In our case, a direct insult to the interventricular septal tissue and patch placement likely disrupted the cardiac conduction system thus permanent pacemaker placement was necessary post-operatively. Given the risk of permanent damage to the electrical conduction system, permanent pacemaker placement should be considered in patients with acquired VSD repair because of infective endocarditis to optimize long term patient outcomes.

Limitations

This patient did not have previous echocardiograms prior to disease onset, making it difficult to rule out any congenital anomalies. However, intraoperative findings revealed necrotic tissue across the interventricular septum. The patient did not have history of a cardiac murmur, and earlier echocardiograms failed to show a significant left-to-right shunt across the interventricular septum. Therefore, an acquired VSD directly from infective endocarditis damage to the cardiac tissue was more likely.

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Glossary

VSD

ventricular septal defect.

TTE

transthoracic echocardiogram.

TEE

transesophageal echocardiogram.