Hoendermis 2015.

Methods	Single‐centre, randomised double‐blind, placebo‐controlled trial 12 weeks duration
Participants	Inclusion criteria: ≥ 18 years with symptomatic HFpEF (LVEF) ≥ 45% NYHA functional class II – IV) PH ‐ diagnosed by mean PAP > 25 mmHg and mean PAWP > 15 mmHg, invasively measured by right‐sided cardiac catheterisation. (WHO Group 2) Exclusion criteria: Severe non‐cardiac limitation to exercise Significant left‐sided valve disease Other causes of pulmonary hypertension n = 52
Interventions	Sildenafil, titrated to 60 mg 3 times a day (N=26), or placebo (N=26)
Outcomes	The primary endpoint was change in mean PAP after 12 weeks Secondary endpoints were change in mean PAWP, cardiac output, and peak oxygen consumption (peak VO2)
Notes	Publicly funded Trial conducted at University of Medical Center Groningen, Hanzeplein, The Netherlands, enrolled between October 2011 and September 2014
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Eligible patients were randomly assigned in a 1:1 ratio according to a computer‐generated random sequence to 1 of the 2 treatment groups using a block size of 4
Allocation concealment (selection bias)	Low risk	Sildenafil and matching placebo were administered orally in tablets and were provided by Pfizer Global Pharmaceuticals, were identical in appearance and were supplied to the study site in identical‐masked kits
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo was used
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Placebo was used
Incomplete outcome data (attrition bias) All outcomes	Low risk	Withdrawals were recorded, and were even across the groups. Quote: "One participant in the sildenafil group withdrew due to heart failure, and four discontinued due to adverse events".
Selective reporting (reporting bias)	Low risk	Prespecified outcomes were accounted for
Other bias	Low risk	Other bias is unlikely