Pre-Operative Sildenafil for Patients With Pulmonary Hypertension Undergoing Mitral Valve Surgery: A Systematic Review and Meta-Analysis.

Background: Pulmonary hypertension is a usual complication of long-standing mitral valve disease. Perioperative pulmonary hypertension is a risk factor for right ventricular failure and is an important cause of morbidity and mortality in patients with pulmonary hypertension undergoing mitral valve surgery. Phosphodiesterase-5 inhibitors particularly sildenafil citrate have proven clinical benefit for pulmonary arterial hypertension but have shown discordant results in group 2 pulmonary hypertension patients. We sought to determine the effect of pre-operative sildenafil on the intra-operative hemodynamic parameters of these patients.

Methods: Studies were included if they satisfied the following criteria: 1) Randomized controlled trials; 2) Adult patients with pulmonary hypertension scheduled for elective mitral valve surgery; and 3) Reported data on changes in pre-, intra-, and post-operative hemodynamic parameters. Using PUBMED, Clinical Key, Science Direct, and Cochrane databases, a search for eligible studies was conducted from September 1 to December 31, 2018. The quality of each study was evaluated using the Cochrane Risk of Bias Tool. The primary outcome of interest is on the effect of pre-operative sildenafil on the improvement of intra-operative hemodynamic parameters such as systolic pulmonary artery pressure (sPAP), mean pulmonary arterial pressure, mean arterial pressure, pulmonary and systemic vascular resistances. We also investigated its effect on the post-operative mortality, length of cardiopulmonary bypass time, ventilation time, and inotrope support requirement. Review Manager 5.3 was utilized to perform analysis of random effects for continuous outcomes.

Results: We identified three studies involving 153 patients with pulmonary hypertension undergoing mitral valve surgery, showing that among those who received pre-operative sildenafil there is a significant decrease in intra-operative systolic pulmonary arterial pressure (mean difference -11.19 (95% confidence interval (CI), -20.23 to -2.15), P < 0.05) and post-operative sPAP (mean difference -13.67 (95% CI, - 19.56 to - 7.78), P < 0.05) without significantly affecting the mean arterial pressure (mean difference 1.94 (95% CI, -5.49 to 9.37), P < 0.05). The systemic and pulmonary vascular resistances were not affected as well.

Conclusions: Administration of pre-operative sildenafil to patients with pulmonary hypertension undergoing mitral valve surgery decreases intra-operative and post-operative systolic pulmonary arterial pressure without significantly affecting other systemic hemodynamic parameters.