The New England Journal of Medicine DECEMBER 06, 2012

Strategies for Multivessel Revascularization in Patients with Diabetes

Michael E. Farkouh, Maria Domanski, Linda A. Sleeper, et al.

Bottom Line

The FREEDOM trial demonstrated that in patients with diabetes and multivessel coronary artery disease, coronary artery bypass grafting (CABG) is superior to percutaneous coronary intervention (PCI) with drug-eluting stents in reducing the composite rate of all-cause mortality, myocardial infarction, and stroke at 5 years.

Key Findings

1. At 5 years, the primary composite endpoint occurred in 26.6% of the PCI group compared to 18.7% in the CABG group (absolute difference 7.9%; P=0.005).
2. The benefit of CABG was driven primarily by a significant reduction in all-cause mortality (16.3% in PCI vs. 10.9% in CABG; P=0.049) and myocardial infarction (13.9% in PCI vs. 6.0% in CABG; P<0.001).
3. Patients in the PCI group experienced a significantly lower rate of nonfatal stroke compared to those in the CABG group (2.4% vs. 5.2%; P=0.03).
4. Repeat revascularization within 1 year was significantly more common in the PCI group compared to the CABG group (12.6% vs. 4.8%; P<0.001).

Study Design

Design
RCT
Open-Label
Sample
1,900
Patients
Duration
5 yr
Median
Setting
Multicenter, Global
Population Adults with type 1 or type 2 diabetes and angiographically confirmed multivessel coronary artery disease amenable to both CABG and PCI.
Intervention Percutaneous coronary intervention (PCI) with drug-eluting stents plus optimal medical therapy.
Comparator Coronary artery bypass grafting (CABG) plus optimal medical therapy.
Outcome Composite of all-cause mortality, nonfatal myocardial infarction, or nonfatal stroke at 5 years.

Study Limitations

The trial was open-label, which introduces potential bias in the management of patients and reporting of subjective outcomes.
Only about 10% of screened patients met the eligibility criteria, potentially limiting the generalizability of findings to the broader diabetic population.
The trial was not specifically powered to detect differences in all-cause mortality as a stand-alone endpoint.
Long-term outcomes (beyond 5 years) rely on a subset of the original population, which may introduce selection bias.

Clinical Significance

The FREEDOM trial establishes CABG as the preferred revascularization strategy for patients with diabetes and multivessel coronary artery disease, directly informing current clinical guidelines by demonstrating a durable mortality benefit despite advancements in drug-eluting stent technology.

Historical Context

The optimal revascularization strategy for diabetic patients with multivessel disease had long been debated. Prior trials like BARI suggested a survival advantage with surgery, but the introduction of drug-eluting stents led many to hypothesize that modern PCI might offer comparable outcomes with lower procedural morbidity; the FREEDOM trial was designed specifically to test this hypothesis in the era of contemporary stent technology.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

How does the pathophysiology of coronary artery disease in diabetic patients, characterized by diffuse involvement and smaller vessel diameters, explain why bypass grafting might be superior to focal stenting?

Key Response

Diabetic patients typically exhibit more extensive, multi-segment, and distal coronary atherosclerosis. While PCI addresses focal lesions, CABG places bypass grafts to the distal, less-diseased portions of the vessels, effectively 'protecting' the entire proximal segment from future plaque rupture and progression, which is more common in the pro-inflammatory diabetic state.

Resident
Resident

The FREEDOM trial reported a higher rate of stroke in the CABG group compared to the PCI group. In clinical practice, how should this risk be balanced against the survival benefit when counseling a diabetic patient with multivessel disease?

Key Response

In FREEDOM, the 5-year stroke rate was 5.2% for CABG vs. 2.4% for PCI. However, the all-cause mortality (10.9% vs. 16.3%) and MI rates (6.0% vs. 13.9%) significantly favored CABG. Clinicians must use a Heart Team approach to weigh the immediate perioperative neurological risks of surgery against the long-term mortality benefit.

Fellow
Fellow

Does the anatomical complexity of coronary disease, as measured by the SYNTAX score, modify the treatment effect of CABG versus PCI in the diabetic population according to the FREEDOM data?

Key Response

Subgroup analyses of the FREEDOM trial suggested that the benefit of CABG over PCI was consistent across all SYNTAX score tertiles (low, intermediate, and high). This implies that in diabetics, the metabolic state itself may be a more important driver of outcomes than the anatomical complexity alone, unlike the general population where PCI is often considered non-inferior for low SYNTAX scores.

Attending
Attending

Given the results of the FREEDOM trial, is there any clinical scenario where PCI with drug-eluting stents should still be considered the preferred initial strategy for a diabetic patient with triple-vessel disease?

Key Response

PCI remains a primary consideration for patients with prohibitive surgical risk (e.g., severe frailty, advanced malignancy, or 'porcelain aorta') or those who prioritize a shorter recovery time despite the known long-term mortality disadvantage. The FREEDOM trial provides the evidentiary basis for informed consent, but patient preference and individual comorbidities remain central to practice.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The FREEDOM trial utilized a composite endpoint of all-cause mortality, non-fatal MI, and non-fatal stroke. What are the statistical limitations of using such a composite when the components (e.g., stroke and MI) move in opposite directions regarding the treatment effect?

Key Response

Composite endpoints assume all components are of equal clinical weight and that the treatment effect is uniform across components. In FREEDOM, CABG reduced MI but increased stroke. If the hazard ratios for individual components differ in direction, the composite can dilute the perceived benefit or harm, necessitating a careful analysis of the individual 'competing' risks to ensure the summary measure isn't misleading.

Journal Editor
Journal Editor

A major criticism of the FREEDOM trial is the use of first-generation drug-eluting stents (DES). How would the inclusion of contemporary second-generation thin-strut DES likely impact the trial's internal and external validity?

Key Response

First-generation DES were associated with higher rates of late stent thrombosis and restenosis compared to modern everolimus-eluting stents. A reviewer would argue that the treatment gap between PCI and CABG might be narrower today, potentially challenging the trial's contemporary generalizability, though subsequent 'real-world' registries still largely support the FREEDOM findings.

Guideline Committee
Guideline Committee

Based on the 5-year FREEDOM data, should current guidelines maintain a Class I recommendation for CABG in diabetic patients with multivessel disease, and how should PCI be graded for the same population?

Key Response

The FREEDOM trial is the cornerstone for the Class I (Level of Evidence A) recommendation for CABG in diabetics with multivessel CAD in both AHA/ACC and ESC guidelines. Because of the clear mortality benefit shown, PCI is typically relegated to a Class IIb or III recommendation in these patients, unless anatomy is simple and the patient is a poor surgical candidate, to ensure evidence-based practice is followed.

Clinical Landscape

Noteworthy Related Trials

2009

BARI 2D Trial

n = 2,368 · NEJM

Tested

Revascularization (CABG or PCI) plus intensive medical therapy

Population

Patients with T2DM and stable ischemic heart disease

Comparator

Intensive medical therapy alone

Endpoint

Death from any cause

Key result: There was no significant difference in the rate of death or major cardiovascular events between revascularization and medical therapy alone among patients with diabetes and stable coronary artery disease.
2009

SYNTAX Trial

n = 1,800 · NEJM

Tested

CABG

Population

Patients with de novo three-vessel disease or left main coronary artery disease

Comparator

PCI with paclitaxel-eluting stents

Endpoint

Major adverse cardiac and cerebrovascular events (MACCE) at 12 months

Key result: CABG remained the standard of care for patients with complex three-vessel or left main disease due to lower rates of major adverse cardiac events compared to PCI.
2015

BEST Trial

n = 880 · NEJM

Tested

CABG

Population

Patients with multivessel coronary artery disease

Comparator

PCI with everolimus-eluting stents

Endpoint

Composite of death, myocardial infarction, and target-vessel revascularization

Key result: CABG resulted in a significantly lower rate of the primary composite endpoint compared with PCI in patients with multivessel coronary disease.

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