A comparison of two different doses of sildenafil in pulmonary arterial hypertension-a prospective randomised controlled study

Sildenafil is an inhibitor of phosphodiesterase 5. Pulmonary vascular resistance caused by pulmonary artery hypertension can be relieved by sildenafil which causes rapid and potent vasodilatation.

Following institutional ethics committee approval, forty patients (using EPI calculator@openepi.com taking the power of study as 80% and-error as 5%) were randomised into two groups. If pulmonary arterial hypertension developed pre-operatively, group A received sildenafil 20mg while group B received sildenafil 40mg. The drug was administered in normal saline with the volume totaling to 50ml. Monitoring was done by cardioscope, SPO2, non-invasive blood pressure (NIBP). Heart rate (HR), systolic and diastolic blood pressures (SBP, DBP), respiratory rate (RR), SPO2 and pulmonary artery pressure were recorded preoperatively (baseline). Any expected and unexpected complications were looked for. Vitals were recorded before shifting the patient to the ward.

Heart rate and oxygen saturation did not show any statistical difference between the two groups. Post-operatively, group A displayed a pulmonary artery pressure of 30.45±5.65mmHg while for group B it was 30.62±6.74mmHg with a statistically significant difference (p-value<0.0001) but no statistically significant difference was seen during the pre-operative and intraoperative period. Hypotension was observed in three (15%) patients from group A and two (10%) patients from group B. Two (10%) patients in group A had bradycardia. Group B did not suffer from bradycardia at any point of time.

Sildenafil is safe and efficacious for controlling pulmonary artery hypertension. 40mg sildenafil displayed a better control than a dose of 20mg sildenafil.