IMPORTANCE OF RIGHT-VENTRICULAR OUTFLOW TRACT ANGIOGRAPHY IN DISTINGUISHING CRITICAL PULMONARY STENOSIS FROM PULMONARY ATRESIA

Objective-To investigate the spectrum of pulmonary atresia and critica l pulmonary stenosis using right ventricular outflow tract angiography and explore its implications for catheter interventional treatment. D esign-Prospective clinical study. Setting-Two paediatric cardiology ce ntres. Subjects-11 neonates or infants (aged 1 day to 8 months; weighi ng 2.3 to 7.8 kg) with pulmonary atresia or where the differentiation of pulmonary atresia from critical pulmonary stenosis was unclear on e ither echocardiography or angiography. Methods-Right ventricular outfl ow tract angiography was performed on all patients to distinguish pulm onary atresia from critical pulmonary stenosis before opening the righ t ventricular outflow tract. Results-Right ventricular outflow tract a ngiography showed that three of seven patients diagnosed as pulmonary atresia by echocardiography had pin hole jets across the pulmonary val ve; another had a probe patent valve that appeared imperforate on both echocardiography and right ventricular outflow tract angiography. Thr ee of the four patients diagnosed by echocardiography as critical pulm onary stenosis were found on right ventricular outflow tract angiograp hy to have pulmonary atresia. The remaining patient had such a tiny or ifice that a second orifice had to be created with a radiofrequency ca theter. The right ventricular outflow tract was opened successfully in 10 of the 11 patients, six of whom required application of radiofrequ ency energy. The right ventricular to aortic systolic pressure ratio f ell from 1.4 (0.9 to 1.9) to 0.6 (0.2 to 1.1) (P < 0.05). All 11 patie nts were alive and well. with transcutaneous oxygen saturations rangin g from 84% to 95% at a median follow up duration of nine months. Concl usions-Critical pulmonary stenosis and pulmonary atresia cannot always be accurately distinguished by echocardiography. Right ventricular ou tflow tract angiography helps to distinguish the two groups. In most c ases the right ventricular outflow tract can be opened without mortali ty and with short to medium term survival.