Trial · NCT00763867

Evaluating the Effectiveness of Sildenafil at Improving Health Outcomes and Exercise Ability in People With Diastolic Heart Failure (The RELAX Study)

NCT00763867, Phase 3, Completed, Duke University; results first posted 2013-07-03

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. Evaluating the Effectiveness of Sildenafil at Improving Health Outcomes and Exercise Ability in People With Diastolic Heart Failure (The RELAX Study). Trials, record NCT00763867. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT00763867

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Evaluating the Effectiveness of Sildenafil at Improving Health Outcomes and Exercise Ability in People With Diastolic Heart Failure (The RELAX Study)
NCT number: NCT00763867
Status: Completed
Phases: Phase 3
Enrollment: 216 participants, actual
Lead sponsor: Duke University
Conditions: Heart Failure
Interventions: Placebo, Sildenafil
First posted: 2008-10-01
Last updated: 2014-07-23
Results first posted: 2013-07-03

Source ClinicalTrials.gov

Registered outcomes45

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Exercise Capacity, as Determined by Peak Oxygen Uptake	Change from Baseline to Week 24
Secondary	Exercise Capacity, as Determined by Peak Oxygen Uptake	Change from Baseline to Week 12
Secondary	Exercise Capacity as Determined by Walk Distance	Change from Baseline to Week 12	6 Minute Walk Distance
Secondary	Composite Score Reflective of Clinical Status	Measured at Week 24	Participants ranked sequentially with ranking stratified in one of three tiers based on: 1. Death (lowest tier) The person with the shortest time from randomization to death is given the lowest rank within the tier. 2. Hospitalizations due to cardiovascular or renal causes (middle tier) For patients alive, the ranking within this tier is based on time to hospitalization from randomization date. The person with the first cardiovascular or renal cause hospitalization will be given the lowest rank within the tier. 3. Change in Minnesota Living with Heart Failure Questionnaire (MLWHFQ) from baseline (highest tier) The use of three tiers within the ranking reflects the greater adverse impact of death or cardiovascular hospitalization on clinical status without an arbitrary assignment as to the relative value of these events in relation to changes in quality of life. Rank order: 1-189 (higher values are better)
Secondary	Exercise Capacity as Determined by Walk Distance	Change from Baseline to Week 24	6 minute walk distance
Secondary	Cardiopulmonary Exercise Test (CPET) Duration	Change from Baseline to Week 12	To interpret the CPET Exercise Duration change endpoints, an increase in exercise duration between Baseline and Week 12/Week 24 is considered to be an improvement
Secondary	Cardiopulmonary Exercise Test (CPET) Duration	Change from Baseline to Week 24	To interpret the CPET Exercise Duration change endpoints, an increase in exercise duration between Baseline and Week 12/Week 24 is considered to be an improvement
Secondary	Ventilatory Anaerobic Threshold	Change from Baseline to Week 12	To interpret the Ventilatory Anaerobic Threshold (VAT) change endpoints, an increase in VAT between Baseline and Week 12/Week 24 is considered to be an improvement
Secondary	Ventilatory Anaerobic Threshold	Change from Baseline to Week 24	To interpret the Ventilatory Anaerobic Threshold (VAT) change endpoints, an increase in VAT between Baseline and Week 12/Week 24 is considered to be an improvement
Secondary	Minnesota Living With Heart Failure Questionnaire (MLWHFQ)	Change from Baseline to Week 12	The MLWHFQ is a self-administered, disease-specific measure of health related quality of life (QOL) that assesses patients perceptions of the influence of heart failure on physical, socioeconomic and psychological aspects of life. Patients respond to 21 items using a six-point response scale (0-5). The total summary score can range from 0-105 with a lower score reflecting better heart failure related QOL. Two sub-scale scores reflect physical (8 items) and emotional (5 items) impairment. Total score: 0 - 105 Physical subscore: 0 - 40 Emotional subscore: 0 - 25

1 to 10 of 45Source ClinicalTrials.gov

See all 45 registered outcomes

Outcomes45

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Exercise Capacity, as Determined by Peak Oxygen Uptake	Change from Baseline to Week 24	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	ml/min/kg	MEAN
SECONDARY	Exercise Capacity, as Determined by Peak Oxygen Uptake	Change from Baseline to Week 12	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	ml/min/kg	MEAN
SECONDARY	Exercise Capacity as Determined by Walk Distance	Change from Baseline to Week 12	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	meters	MEAN
SECONDARY	Composite Score Reflective of Clinical Status	Measured at Week 24	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	units on a scale	MEAN
SECONDARY	Exercise Capacity as Determined by Walk Distance	Change from Baseline to Week 24	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	meters	MEAN
SECONDARY	Cardiopulmonary Exercise Test (CPET) Duration	Change from Baseline to Week 12	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	minutes	MEAN
SECONDARY	Cardiopulmonary Exercise Test (CPET) Duration	Change from Baseline to Week 24	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	minutes	MEAN
SECONDARY	Ventilatory Anaerobic Threshold	Change from Baseline to Week 12	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	ml/min/kg	MEAN
SECONDARY	Ventilatory Anaerobic Threshold	Change from Baseline to Week 24	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	ml/min/kg	MEAN
SECONDARY	Minnesota Living With Heart Failure Questionnaire (MLWHFQ)	Change from Baseline to Week 12	Participants analyzed consisted of those participants who had the endpoint data available to be derived.	units on a scale	MEAN

1 to 10 of 45Source ClinicalTrials.gov

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Results by group90

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Spread	Units
Exercise Capacity, as Determined by Peak Oxygen Uptake	Placebo	-0.07	Standard Deviation 2.00	ml/min/kg
Exercise Capacity, as Determined by Peak Oxygen Uptake	Sildenafil	-0.12	Standard Deviation 2.29	ml/min/kg
Exercise Capacity, as Determined by Peak Oxygen Uptake	Placebo	0.02	Standard Deviation 1.70	ml/min/kg
Exercise Capacity, as Determined by Peak Oxygen Uptake	Sildenafil	0.03	Standard Deviation 2.20	ml/min/kg
Exercise Capacity as Determined by Walk Distance	Placebo	26.2	Standard Deviation 83.7	meters
Exercise Capacity as Determined by Walk Distance	Sildenafil	5.2	Standard Deviation 69.1	meters
Composite Score Reflective of Clinical Status	Placebo	95.8	Standard Deviation 55.0	units on a scale
Composite Score Reflective of Clinical Status	Sildenafil	94.2	Standard Deviation 54.6	units on a scale
Exercise Capacity as Determined by Walk Distance	Placebo	17.5	Standard Deviation 88.6	meters
Exercise Capacity as Determined by Walk Distance	Sildenafil	12.0	Standard Deviation 94.2	meters

1 to 10 of 90Source ClinicalTrials.gov

See all 90 results by group

Participant flow6

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Placebo	103
Overall Study	STARTED	Sildenafil	113
Overall Study	COMPLETED	Placebo	98
Overall Study	COMPLETED	Sildenafil	101
Overall Study	NOT COMPLETED	Placebo	5
Overall Study	NOT COMPLETED	Sildenafil	12

Source ClinicalTrials.gov

Adverse events96

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Angina Pectoris	Cardiac disorders	Placebo	2	103
other	Angina Pectoris	Cardiac disorders	Sildenafil	0	113
other	Atrial Fibrillation	Cardiac disorders	Placebo	4	103
other	Atrial Fibrillation	Cardiac disorders	Sildenafil	0	113
other	Atrial Flutter	Cardiac disorders	Placebo	1	103
other	Atrial Flutter	Cardiac disorders	Sildenafil	1	113
other	Atrioventricular Block Second Degree	Cardiac disorders	Placebo	1	103
other	Atrioventricular Block Second Degree	Cardiac disorders	Sildenafil	0	113
other	Cardiac Failure	Cardiac disorders	Placebo	1	103
other	Cardiac Failure	Cardiac disorders	Sildenafil	5	113

1 to 10 of 96Source ClinicalTrials.gov

See all 96 adverse events

Adverse event totals6

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Placebo
Total, all-cause mortality	Sildenafil
Total, other adverse events	Placebo	72	103
Total, other adverse events	Sildenafil	83	113
Total, serious adverse events	Placebo	16	103
Total, serious adverse events	Sildenafil	25	113

Source ClinicalTrials.gov

Papers13

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
22991405	DERIVED	PubMed
23478662	RESULT	PubMed
24162898	DERIVED	PubMed
24833648	DERIVED	PubMed
25104521	DERIVED	PubMed
27072860	DERIVED	PubMed
28194841	DERIVED	PubMed
28214792	DERIVED	PubMed
31272568	DERIVED	PubMed
31805424	DERIVED	PubMed

1 to 10 of 13

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Grants1

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

Project	Title	Principal investigators	Organization	Funder	Fiscal years
U01HL084904	Heart Failure Clinical Research Network - DCC	LEE, KERRY L	DUKE UNIVERSITY	NATIONAL HEART, LUNG, AND BLOOD INSTITUTE	2006 to 2011

Source NIH RePORTER

Trial comparisons1

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

Comparison
Sildenafil vs Placebo: serious adverse events

Source Trial comparisons

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

The record and each of its lists are JSON, twenty rows a page. No key.

GET https://conductscience.org/api/trials/v1/NCT00763867

GET https://conductscience.org/api/trials/v1/NCT00763867/registered?page=2

API reference For AI assistants