Late occurrence of ventricular septal rupture after deep septal myectomy for hypertrophic cardiomyopathy: Causes and management

Abstract

Surgical septal myectomy is increasingly utilized for patients with hypertrophic obstructive cardiomyopathy who remain symptomatic despite maximum doses of medical therapy. Deep and extensive septal muscle resections may lead to iatrogenic ventricular septal defects that are detected on transesophageal echocardiography immediately after weaning from cardiopulmonary bypass and immediately corrected in the same surgery. However markedly thinned out ventricular septum after myectomy may be prone to late rupture from high left ventricular systolic pressures causing delayed detection of a ventricular septal defect when the patients present with new onset symptoms. Additionally, a surgical injury to the first septal perforator artery during the myocardial resection leading to septal infarction may contribute to delayed occurrence of ventricular septal defect. Such a predisposing deep septal resection or septal infarction may be associated with varying degrees of atrioventricular nodal block warranting a permanent pacing. A new onset interventricular shunt from such an iatrogenic ventricular septal defect often leads to heart failure as the filling pressures increase disproportionately in the thick hypertrophied left ventricle. Transcatheter closure is an alternative to a high-risk repeat surgery. This report of device closure of two delayed septal ruptures after myectomy discusses the reasons, presentation, catheter approaches, and procedural challenges. <Learning objective: Deep extended septal myectomy for medically refractory hypertrophic obstructive cardiomyopathy may lead to early or late iatrogenic ventricular septal defect. Such an extensive loss of septal muscle may be additionally indicated by co-occurrence of atrioventricular nodal block that needs permanent pacing. Heart failure from the new onset interventricular shunt is not clinically tolerated by the hypertrophied left ventricle due to elevated end diastolic pressures. Transcatheter closure of the ventricular septal defect is an attractive alternative to a morbid repeat surgery.>.

Keywords: Device closure; Hypertrophic cardiomyopathy; Septal myectomy; Ventricular septal rupture.

Fig. 1

Thinned out basal ventricular septum between left (LV) and right ventricle (RV) in the immediate postoperative echocardiogram (A) later ruptured after one year to an 8-mm ventricular septal defect (red arrow) adjacent to left ventricular outflow tract (LVOT) shown with color Doppler flows in a magnified parasternal short-axis view (B). After closure with a device (yellow arrow), there was no residual flow (C). RA, right atrium; LA, left atrium.

Fig. 2

Left ventriculogram in the first patient in left anterior oblique projection (A) demonstrates 8-mm defect (red arrow) below the aortic valve closed (B) with a device (yellow arrow).

Fig. 3

Left ventriculogram in the second patient (A) shows a defect below the aortic (Ao) valve between the left (LV) and right (RV) ventricles. After retrograde passage of a shuttle sheath (B), the defect was closed (C) with a multifunction occluder (MFO) device without any residual flows (D).