Hemodynamic outcomes in patients undergoing bidirectional cavopulmonary connection with additional or antegrade pulmonary blood flow: a single-centre retrospective study.

Background: The bidirectional cavopulmonary connection (BCPC) is a pivotal stage in the surgical palliation of single-ventricle patients. However, there is ongoing debate regarding the benefits and drawbacks of BCPC with additional or antegrade pulmonary blood flow (AAPBF) in optimizing the subsequent stage-total cavopulmonary connection (TCPC). Objective: To determine the influence of BCPC with AAPBF on pulmonary artery growth and hemodynamic outcomes. Methods: A retrospective review was conducted of 167 single-ventricle patients who underwent BCPC at Siriraj Hospital between 2006 and 2022. Patients were categorized into two groups based on AAPBF status: group 1 (with AAPBF, n = 44) and group 2 (without AAPBF, n = 123). Variables from pre-BCPC and pre-TCPC cardiac catheterization-including pulmonary artery growth, McGoon ratio, Nakata index, mean pulmonary arterial pressure (mPAP), ventricular end-diastolic pressure (EDP), and indexed pulmonary vascular resistance (PVRi)-were compared between groups. Pulmonary artery branch z-scores were analyzed and adjusted using analysis of covariance (ANCOVA). Survival rate, all-cause mortality, and incidence of atrioventricular valve regurgitation (AVVR) and pulmonary arteriovenous malformation (AVM) were also assessed. Results: Median ages at pre-BCPC assessment were 1.06 years (group 1) and 2.17 years (group 2), and at pre-TCPC assessment were 6.19 and 7.27 years, respectively. Median age at BCPC operation was similar between groups (1.58 vs. 1.51 years). Over a median follow-up of 64.33 months, group 1 showed significantly greater increases in right and left pulmonary artery size compared to group 2 (RPA: 3.27 vs. 1.6 mm (p = 0.019); LPA: 2.38 vs. 0.88 mm (p = 0.004)). The Nakata index increased in group 1 but decreased in group 2 (26.70 vs. -84.67 mm2/m2, p < 0.001). Z-scores confirmed significant growth in both pulmonary arteries when adjusted for body surface area (p < 0.001). No significant differences were found in pre-BCPC mPAP (16 vs. 15 mmHg, p = 0.38), EDP (12 vs. 12 mmHg, p = 0.584), or PVRi (1.77 vs. 2.03 WU m2, p = 0.890). Survival rates did not differ significantly between groups (p = 0.350). Conclusions: BCPC with AAPBF effectively promotes pulmonary artery growth without adversely affecting ventricular volume loading or pulmonary artery pressure. Further investigation into the development of arteriovenous malformations is recommended.