New England Journal of Medicine January 20, 2000

Effects of an Angiotensin-Converting–Enzyme Inhibitor, Ramipril, on Cardiovascular Events in High-Risk Patients

The Heart Outcomes Prevention Evaluation Study Investigators

Bottom Line

In high-risk patients without known left ventricular dysfunction or heart failure, the ACE inhibitor ramipril significantly reduced the rates of death, myocardial infarction, and stroke compared to placebo.

Key Findings

1. The primary composite outcome (myocardial infarction, stroke, or cardiovascular death) occurred in 14.0% of the ramipril group (651 patients) versus 17.8% of the placebo group (826 patients) (relative risk [RR], 0.78; 95% confidence interval [CI], 0.70 to 0.86; P<0.001).
2. Ramipril significantly reduced the rate of death from cardiovascular causes (6.1% vs. 8.1%; RR, 0.74; P<0.001) and death from any cause (10.4% vs. 12.2%; RR, 0.84; P=0.005).
3. Myocardial infarction occurred significantly less frequently in the ramipril group (9.9% vs. 12.3%; RR, 0.80; P<0.001), as did stroke (3.4% vs. 4.9%; RR, 0.68; P<0.001).
4. Treatment with ramipril also significantly decreased the rates of new heart failure (9.1% vs. 11.6%; RR, 0.77; P<0.001) and revascularization procedures (16.3% vs. 18.8%; RR, 0.85; P<0.001).
5. The intervention reduced the incidence of cardiac arrest (0.8% vs. 1.3%; RR, 0.62; P=0.02) and complications related to diabetes (6.4% vs. 7.6%; RR, 0.84; P=0.03).

Study Design

Design
Randomized Controlled Trial
Double-Blind
Sample
9,297
Patients
Duration
5 yr
Median
Setting
Multicenter, international
Population High-risk patients aged 55 years or older with evidence of vascular disease or diabetes plus one other cardiovascular risk factor, not known to have a low ejection fraction or heart failure.
Intervention Ramipril 10 mg once per day orally
Comparator Matching placebo
Outcome Composite of myocardial infarction, stroke, or death from cardiovascular causes

Study Limitations

• The trial specifically selected a high-risk population aged 55 years or older, so the findings may not be directly generalizable to younger patients or those at lower cardiovascular risk.
• Since patients with known low ejection fraction or heart failure were intentionally excluded, the study evaluated a specific prophylactic role, rather than treatment of active heart failure.
• The 2-by-2 factorial design with vitamin E could introduce analytical complexity, although the companion paper reported that vitamin E did not significantly affect these outcomes.

Clinical Significance

The HOPE trial was a landmark study that established ramipril as a foundational therapy for the secondary prevention of cardiovascular events in a broad spectrum of high-risk patients, shifting clinical guidelines to recommend ACE inhibitors even in the absence of heart failure or reduced ejection fraction.

Historical Context

Prior to this publication, ACE inhibitors were well-established as treatments for hypertension and were known to improve survival in patients with heart failure or left ventricular dysfunction following a myocardial infarction. The HOPE trial was designed to test whether ACE inhibition could prevent cardiovascular events in high-risk patients who did not yet have heart failure or known left ventricular dysfunction, and its dramatically positive results fundamentally changed preventative cardiology.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

How does ramipril's mechanism of action explain its cardiovascular protective effects, such as reducing myocardial infarction and stroke, beyond simply lowering blood pressure?

Key Response

This question tests foundational pharmacology and pathophysiology. Students should recognize that ACE inhibitors not only decrease Angiotensin II (reducing sympathetic activity, vasoconstriction, and harmful cardiac/vascular remodeling) but also prevent the breakdown of bradykinin, leading to increased nitric oxide and prostaglandins which promote vasodilation and endothelial protection.

Resident
Resident

Based on the inclusion criteria and results of the HOPE trial, which specific patient populations in your clinic should be started on an ACE inhibitor like ramipril even if they are normotensive and have a normal ejection fraction?

Key Response

This focuses on direct clinical application and guidelines. Residents should identify that the HOPE trial established the use of ACE inhibitors for secondary prevention in patients with established coronary artery disease, peripheral arterial disease, previous stroke, or diabetes with at least one other cardiovascular risk factor, independent of heart failure or baseline blood pressure.

Fellow
Fellow

The HOPE trial noted a significant reduction in new-onset diabetes as a secondary endpoint. What are the hypothesized pathophysiological mechanisms for this, and how did subsequent trials (such as the DREAM trial) challenge the use of RAS blockade for primary diabetes prevention?

Key Response

Fellows should be able to synthesize unexpected secondary endpoints with advanced pathophysiology (e.g., ACE inhibition improving skeletal muscle blood flow, modulating adiponectin, or preserving pancreatic islet blood flow) and integrate subsequent evidence. The DREAM trial specifically tested ramipril for diabetes prevention in high-risk patients and found no significant reduction, illustrating the danger of over-relying on secondary endpoints from previous trials.

Attending
Attending

The reported blood pressure reduction in the ramipril group of the HOPE trial was minimal (approximately 3/2 mmHg), yet the cardiovascular benefits were substantial. How do you teach trainees to interpret this 'blood pressure-independent' pleiotropic effect, and does this imply a unique class effect for highly lipophilic, tissue-penetrating ACE inhibitors?

Key Response

This question addresses a classic attending-level teaching point regarding the disconnect between surrogate markers (clinic BP) and hard outcomes. It invites discussion on whether the benefits are truly pleiotropic and tissue-specific, or if they were merely an artifact of inadequate 24-hour blood pressure monitoring (which later sub-studies suggested may have missed larger nocturnal BP drops).

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The HOPE trial was terminated early by the Data and Safety Monitoring Board (DSMB) due to clear evidence of benefit. What are the statistical and methodological risks of early trial truncation for benefit, particularly regarding the estimation of treatment effect size?

Key Response

This targets expert-level methodology. PhD researchers should understand the 'truncation effect' or 'random high' phenomenon, where trials stopped early for benefit often overestimate the true magnitude of the treatment effect because stopping rules are frequently crossed during a random statistical peak in the data.

Journal Editor
Journal Editor

The authors heavily emphasize that the profound cardiovascular benefits observed in the HOPE trial were independent of blood pressure lowering, citing a mere 3.2/1.4 mmHg difference in clinic BPs. As a statistical reviewer, what critical methodological flaw in their blood pressure assessment strategy threatens this conclusion, and how would you demand this be addressed?

Key Response

A seasoned editor would flag that relying solely on episodic in-clinic blood pressure measurements is inadequate to claim BP-independent effects. The reviewer would demand ambulatory blood pressure monitoring (ABPM) data, which (as shown in the HOPE ABPM substudy) revealed a much more substantial 24-hour and nocturnal blood pressure reduction that likely accounts for a large portion of the observed clinical benefit.

Guideline Committee
Guideline Committee

The HOPE trial was instrumental in establishing ACC/AHA and ESC Class I recommendations for ACE inhibitors in high-risk vascular patients without heart failure. In updating current guidelines for a normotensive patient with diabetes and established CAD, how should the committee weigh the legacy recommendation of ramipril against the introduction of SGLT2 inhibitors and GLP-1 receptor agonists?

Key Response

This requires integrating foundational landmark trial evidence with modern guideline evolution. The committee must consider whether ACE inhibitors remain a mandatory first-line backbone therapy for vascular protection in the absence of hypertension, or if compelling indications for newer agents with robust cardiovascular and renal mortality benefits (like SGLT2i and GLP-1 RAs) should supersede or mandate co-administration based on the latest ADA and AHA/ACC guidelines.

Clinical Landscape

Noteworthy Related Trials

2003

EUROPA Trial

n = 12,218 · Lancet

Tested

Perindopril 8mg daily

Population

Patients with stable coronary artery disease without heart failure

Comparator

Placebo

Endpoint

Composite of CV death, non-fatal MI, or cardiac arrest

Key result: Perindopril significantly reduced the relative risk of the primary endpoint by 20% compared to placebo.
2004

PEACE Trial

n = 8,290 · NEJM

Tested

Trandolapril 4mg daily

Population

Patients with stable coronary artery disease and normal left ventricular function

Comparator

Placebo

Endpoint

Composite of CV death, non-fatal MI, or coronary revascularization

Key result: Trandolapril did not significantly reduce the incidence of the primary composite endpoint compared to placebo in this lower-risk population.
2008

ONTARGET Trial

n = 25,620 · NEJM

Tested

Telmisartan 80mg daily

Population

Patients with vascular disease or high-risk diabetes without heart failure

Comparator

Ramipril 10mg daily or combination

Endpoint

Composite of CV death, MI, stroke, or hospitalization for heart failure

Key result: Telmisartan was non-inferior to ramipril for the primary outcome, and the combination offered no additional benefit but more adverse events.

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