Sastry 2004.

Methods	Randomised, double‐blind, cross‐over trial 6 weeks duration
Participants	Inclusion criteria: 12 and 65 years of age PAH NYHA functional class II to III An estimated mean PAP > 30 mmHg on Doppler echocardiography Able to walk on a treadmill. (WHO Group 1) Exclusion criteria: NYHA functional class IV Significant right‐to‐left shunt Valvular heart disease Left ventricular systolic dysfunction Systemic hypertension Secondary pulmonary hypertension Other severe co‐morbid conditions WHO FC II/III n = 22
Interventions	Sildenafil compared to placebo Medication dosage was assigned on the basis of body weight, with participants weighing up to 25 kg receiving 25 mg 3 times daily, those weighing between 26 and 50 kg receiving 50 mg 3 times daily, and those weighing 51 kg receiving 100 mg 3 times daily Digoxin, diuretics, and oral anticoagulants were used at the clinician’s discretion. No other vasodilators were allowed, and participants were specifically advised not to take nitrate preparations in any form
Outcomes	Time spent on treadmill PASP Cardiac index as measured on doppler echocardiography Adverse events Quality of life (a chronic heart failure questionnaire with 16 questions, including 5 to assess dyspnoea, 4 to assess fatigue, and 7 to assess emotional function of daily living. The answers to each question may be scored from 1 (denoting worst function) to 7 (denoting best function). The maximum possible score of 108 would denote the best QOL, whereas a minimum score of 16 would denote worst QOL)
Notes	PAH diagnosed on echo, did not use right‐heart catheterisation Funding source not stated Trial was conducted at CARE Hospital, Hyderabad, India, between September 17, 2002, and December 13, 2002
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was performed on the basis of computer‐generated random numbers
Allocation concealment (selection bias)	Low risk	Placebo‐controlled
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo‐controlled
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The participant, clinical investigator, echocardiographer, and the person supervising the exercise were blinded to the participant’s treatment regimen
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Withdrawals were reported and similar across groups: Quote: "One participant in the sildenafil first group opted out of the study one week after randomisation. This was not the result of any serious adverse effect of medication. Another participant in the placebo‐first group died one week after randomisation".
Selective reporting (reporting bias)	Low risk	Prespecified outcomes were reported
Other bias	Low risk	Other risk of bias is unlikely