Outcome of congenital heart disease with left-to-right shunts and pulmonary arterial hypertension undergoing operability assessment by acute vasodilator testing: The AIIMS operability score

Background: Pulmonary artery hypertension associated with left-to-right intracardiac shunts adversely affects outcomes. Studies are limited to guide the decision to operate or not in patients presenting late with a left-to-right shunt and PAH. This study aimed to assess clinical and investigative parameters, including acute vasodilator testing (AVT) using oxygen, to predict operability decisions and outcomes. Materials and Methods: We conducted a retrospective analysis of patients who underwent cardiac catheterization for operability assessment over 5 years, excluding those with left-heart obstructive disease or residual postoperative lesions. A total of 157 patients (mean age: 12.8 ± 12.6 years; 83 males) were included, with the majority having post-tricuspid shunt lesions (132/157, 84%). Multiple logistic regression identified predictors of inoperability on AVT, including age >2 years, absence of cardiomegaly, bidirectional or predominantly right-to-left shunting across the defect, and absence of left ventricular volume overload on echocardiography. These variables formed a scoring system with 80% specificity and 60% sensitivity for predicting inoperability. Results: Of the 157 patients, 60 underwent surgical correction, with six experiencing right heart failure or death post-operatively, and three facing adverse outcomes during further follow-up. Univariate analysis indicated that age >2 years, hemoglobin levels, single or narrowly split second heart sound, cyanosis, and a postoxygen Qp: Qs ratio <0.9 were significantly associated with unfavorable outcomes among patients who underwent surgery. In the multivariate analysis, none of the parameters predicted an unfavorable surgical outcome. Conclusions: This study highlights the importance of simple clinical and non-invasive parameters in assessing operability among patients with left-to-right intracardiac shunts and severe PAH. However, none of the parameters were independently predictive of operative outcome. A simple AIIMS operability score based on clinical and noninvasive parameters can predict inoperability with acceptable sensitivity and specificity. However, the score should be validated in larger prospective studies.