Pulmonary atresia with intact ventricular septum and right ventricular dependent coronary circulation through the “vessels of Wearn”

We present an autopsy case of a male baby born at 35 weeks of gestation with pulmonary atresia with intact ventricular septum (PAIVS), who had coronary blood flow that was dependent on outflow from the right ventricle through the vessels described by Wearn. At 7 weeks of age, he underwent single ventricle palliation consisting of ligation of a patent ductus arteriosus and placement of a modified Blalock-Taussig shunt. The patient experienced a perioperative myocardial infarction, requiring extracorporeal membrane oxygenation. Progressive hemodynamic decline resulted in death 8 days after surgery. Autopsy revealed acute and remote infarctions in both ventricles and fibromuscular dysplasia of the subepicardial and intramural coronary arteries. In 1926, Grant first reported the association between PAIVS and secondary dysplasia of the heart vasculature and hypothesized that the high pressure resulted in dilation of the myocardial sinusoids. Confusion secondary to the unmeritorious dismissal of the myocardial sinusoids has obscured the pathogenesis of PAIVS and led to several publications suggesting second heart field abnormalities as a disease model for PAIVS. We discuss the pathogenesis of PAIVS, the ventriculocoronary arterial connections and the sinusoidal relationship to the vessels described by Wearn, and we attempt to correct the solecism plaguing the nomenclature of myocardial vasculature.