Spontaneously Closed VSD Presenting as an Iatrogenic Gerbodie Defect

A 29-year-old female patient with symptomatic rheumatic heart disease was confirmed to have severe mitral regurgitation and mild to moderate tricuspid regurgitation on echocardiographic examination. The diseased mitral valve leaflets were excised with posterior chordal preservation and replaced with a 31 mm TTK Chitra mechanical prosthetic valve through a midline sternotomy and trans-left atrial approach. 
 
The immediate postoperative course was uneventful. She was extubated on the day of surgery, inotropes were tapered off, and an echocardiogram on the first postoperative day showed normal prosthetic valve function with no leaks, a transvalvular gradient of 5 mm Hg, mild tricuspid regurgitation (TR), and a tricuspid regurgitation pressure gradient (TRPG) of 40 mm Hg, along with a trace pericardial effusion. The mediastinal drain and pacing wires were removed on postoperative day three, but the right pleural drain was retained due to higher output. She developed sepsis, and antibiotics were escalated. On day five, an echocardiogram showed normal valve function, with no leaks and a transvalvular gradient of 5 mm Hg, along with a trace pericardial effusion. 
 
Over the next five days, the patient gradually developed signs of heart failure, such as easy fatigue, generalized weakness, breathlessness requiring oxygen support, pedal edema, persistent serous pleural drainage of about 250 ml per day, and the need for inotropic support. 
 
On the eleventh postoperative day, echocardiographic examination revealed good prosthetic valve motion, a gradient of 6 mm Hg, trivial transvalvular regurgitation, no vegetation or thrombus, noncoaptation of the tricuspid valve leaflets, free tricuspid regurgitation, a TRPG of 23 mm Hg, a Gerbode defect (LV to RA shunt) with a gradient of 108 mm Hg, dilated right atrium, fair left ventricular function, TAPSE of 15 mm, dilated IVC (17 mm, non-collapsible), and no pericardial effusion. 
 
The patient was taken for surgery with the plan of Gerbode defect closure. A redo sternotomy was performed, and cardiomegaly was noticed. The right atrium was bright red, dilated, and had a palpable thrill. The right ventricle was dilated. Aorto-bicaval cannulation was performed, and cardiopulmonary bypass was initiated. The right atrium was opened, and a bright red jet of blood was seen from the inferomedial aspect of the right atrium. The aorta was cross-clamped, cardioplegia was delivered, and the interatrial septum was incised. 
 
A 1x1 cm perforation was identified in the septal leaflet of the tricuspid valve near the annulus, communicating with the left ventricle. Upon detailed examination, a perimembranous ventricular septal defect was found, which was spontaneously closed by the septal leaflet of the tricuspid valve. The valve sutures placed around the mitral valve annulus were seen passing through the septal leaflet of the tricuspid valve, which had covered the ventricular septal defect adjacent to the mitral valve annulus. The sutures had cut through the septal leaflet, creating a defect in the already closed membranous septal defect, resulting in a shunt from the left ventricle toward the right atrium. The mitral valve sutures were intact, and the prosthetic valve was functioning well with no leak. The tricuspid annulus was dilated, and a few chordae of the septal leaflet were tethered, resulting in noncoaptation of the tricuspid valve leaflets. 
 
The acquired left ventricular-right atrial communication is increasing compared to congenital cases (1). 
 
Riemenschneider and Moss classified these defects as direct (shunt through the membranous septum) or indirect (associated with VSD and TR) (2). Sakakibara and Konno further categorized defects as supravalvular, infravalvular, or intermediate (3), with incidences of 76 percent, 16 percent, and 8 percent, respectively. 
 
The current patient had an infravalvular defect. The relationship between the cardiac skeleton and the position of the atrioventricular valve annuli to the interventricular septum is critical. During mitral valve replacement, the sutures around the mitral annulus can pass through the ventricular muscle or septum. Careful technique is required to minimize trauma to this area and prevent suture cut-through. 

In similar cases in which the membranous septum is absent, the valve suture bites have the possibility of passing through the tricuspid septal leaflet on the other side of the septal defect. 
 
During the second surgery, the defect in the tricuspid septal leaflet was closed with autologous pericardium using 5-0 Prolene sutures, avoiding the conduction bundle area. The fibrosed portion of the septal leaflet covering the membranous septal defect was left undisturbed. Secondary chordae were released, and anteroseptal commissuroplasty and modified DeVega’s suture annuloplasty were performed. The saline insufflation test showed mild tricuspid regurgitation. The right atrium was closed, and the patient was weaned from cardiopulmonary bypass . 
 
Intraoperative transesophageal echocardiography confirmed no residual shunt, normal prosthetic valve function, and good left ventricular function. Postoperatively, the patient was extubated after six hours and showed symptomatic improvement. Follow-up echocardiography revealed normal prosthetic valve function, no transvalvular or paravalvular leaks, a gradient of 4 mm Hg, no residual LV-RA shunt, trivial TR, a TRPG of 40 mm Hg, an LVEF of 55 percent, and mild pericardial effusion. The patient was discharged after four days. 

References

1. Yuan SM. A Systematic Review of Acquired Left Ventricle to Right Atrium Shunts (Gerbode Defects). Hellenic J Cardiol. 2015 Sep-Oct;56(5):357-72. PMID: 26429364.
2. Riemenschneider TA, Moss AJ. Left ventricular-right atrial communication. Am J Cardiol. 1967 May;19(5):710-8. doi: 10.1016/0002-9149(67)90476-6. PMID: 6023467.
3. SAKAKIBARA S, KONNO S. Congenital aneurysm of the sinus of Valsalva. Anatomy and classification. Am Heart J. 1962 Mar;63:405-24. doi: 10.1016/0002-8703(62)90287-9. PMID: 14496167.

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