Short Term Follow-up in Patients with Stable Chronic Heart Failure on 5-Phosphodiesterase Inhibitor Sildenafil

Abstract
Background: The increased Pulmonary Artery (PA) pres-sure is due to disturbances in key vascular mediator pathway including relative deficiencies of vasodilators such as Nitric Oxide (NO) and prostacyclins. Vasodilators such as 5- phosphodiesterase Inhibitor (sildenafil) are a natural initial therapeutic choice.
Objectives: The study was designed to investigate whether a 50mg twice daily of sildenafil could improve exercise performance, ventilatory efficiency, oxygen uptake kinetics and pulmonary hypertension in patients with stable Chronic Heart Failure (CHF).
Methods: Single center, double-blind, placebo-controlled, parallel-group, randomized clinical trial of one hundred patients with stable CHF, Group (A) including fifty patients who received only the standard therapy of CHF (control group), Group (B) including fifty patients who received Sildenafil in addition to standard CHF therapy (active group) for six months. All patients who met screening criteria under-went baseline studies (history and physical examination, cardiopulmonary exercise tests including [peak exercise (VO2 peak), ventilatory efficiency (VE/VCO2 slope) and Recovery Gas Exchange (T1/2VO2min- T1/2VCO2min)] and echocar-diography for assessment of mean Pulmonary Artery Pressure (mPAP) and LV systolic function) and were then randomly assigned in a 1:1 ratio, to receive either sildenafil or placebo.
Results: There was statistically significant difference between Group (A) and Group (B), significant improvement in VO2 peak,VE/VCO2 slope, T-1/2Vo2 (min), T-1/2VCO2 (min) and mean Pulmonary Artery Pressure (mPAP) occurred in Sildenafil group (group B) with p-value <0.05, while in the control group (group A), there was no significant improve-ment in all parameters. After using sildenafil in patient with stable CHF for 6 months the mPAP decreased by 20% in sildenafil group and 2% in the controlled group. There was also improvement in ventilatory efficiency and exercise performance.
Conclusion: 5-phosphodiesterase Inhibitor (sildenafil) may be benificial as adjunctive therapy for patients with Chronic Heart Faluire (CHF).