This case represents the most severe morphological variant of pulmonary atresia with intact septum in which marked hypoplasia of the right ventricle is present leaving only a small inlet cavity together with severely hypo plastic tricuspid annulus. The hypertensive right ventricle (marked elevation of both end systolic and end diastolic RV pressures due to RV outflow tract atresia and intact ventricular septum) forces the blood mainly through the intra myocardial sinusoids with consequent fistulous communication with the epicardial RCA branches and by a lesser extent through the small tricuspid valve annulus as a trivial regurgitation. The main outflow of the hypertensive RV will be the fistulous connection with the RCA for which a systolic retrograde flow in the ectatic proximal RCA is noted1,2. This retrograde filling of the coronary circulation from the hypertensive right ventricle carries the risk of right ventricle dependent coronary circulation if there is associated atresia or stenoses in the proximal major coronary arteries that could be visualized by an angiographic study in post natal life3.
This morphological variant of the pulmonary atresia with intact septum and ventriculo-coronary communication represents a critical condition that prompt the early postnatal prostaglandin infusion to maintain ductal patency. The second immediate intervention should be either ductal stenting (could not be done in this case owing to marked tortuousity of the arterial duct) or modified Blalock Tausig Shunt (of choice in this case) to enhance the arterial growth of the confluent branch pulmonary arteries prior to total palliative repair by a single ventricle procedures.
Surgical RV decompression (RV to pulmonary artery valved conduit) in this case will be of no value because the residual small inlet cavity will not be sufficient to act as a single pulmonary ventricle as well as the associated risk if there is right ventricle dependent coronary circulation (RVDCC) as there will be catastrophic myocardial infarction and even myocardial rupture and neonatal death if surgical RV decompression is done in the presence of RVDCC (Steal phenomenon)4.
1- Chaoui R, Tennstedt C, Goldner B, Bollman R. Prenatal diagnosis of ventriculo-coronary communications in a second trimester fetus using transvaginal and transabdominal color Doppler sonography. Ultrasound Obstet Gynecol 1997; 9:194–197.
2- F. TADDEI, M. SIGNORELLI, C. GROLI, S. SCALCHI and U. A. BIANCHI. Prenatal diagnosis of ventriculo-coronary arterial communication associated with pulmonary atresia. Ultrasound Obstet Gynecol 2003; 21: 413–415.
3-Powell AJ, Mayer JE, Lang P, Lock JE. Outcome in infants with pulmonary atresia, intact ventricular septum, and right ventricle-dependent coronary circulation. Am J Cardiol 2000;86:1272–4.
4- Kristine J. Guleserian, Laurie B. Armsby, Ravi R. Thiagarajan, Pedro J. del Nido and John E. Mayer. Natural History of Pulmonary Atresia With Intact Ventricular Septum and Right-Ventricle–Dependent Coronary Circulation Managed by the Single-Ventricle Approach. Jr Ann Thorac Surg 2006;81:2250-2258.