Veterans Affairs (VA) Non-Q-Wave Infarction Strategies In-Hospital - VANQWISH

Description:

Invasive vs. conservative management strategy in non-Q-wave MI.

Hypothesis:

To compare an invasive with a conservative strategy in patients with acute non-Q-wave myocardial infarction.

Study Design

Study Design:

Patients Screened: 2738
Patients Enrolled: 920
Mean Follow Up: 23 months
Mean Patient Age: 62
Female: 3

Patient Populations:

Evolving acute myocardial infarction.
Creatine kinase MB (CK-MB) isoenzymes that was more than 1.5 times the upper limit of normal.
No new abnormal Q waves (or R waves) on serial electrocardiograms.

Exclusions:

Serious coexisting conditions.
Persistent or recurrent ischemia at rest despite intensive medical therapy.
Severe heart failure despite intravenous diuretics, vasodilators, or both.
The above conditions were deemed to pose clinical or ethical problems for the inclusion of patients in a randomized trial.

Primary Endpoints:

Death from any cause or recurrent nonfatal infarction during a minimum of 12 months of follow-up.

Secondary Endpoints:

Overall mortality and major procedural complications after coronary angiography or myocardial revascularization.

Drug/Procedures Used:

Invasive management (routine angiography) vs. "conservative" management (medical therapy and noninvasive testing, with subsequent invasive management if indicated by the development of spontaneous or inducible ischemia).

Principal Findings:

A total of 920 patients were randomized, 462 to the invasive-strategy group and 458 to the conservative-strategy group.

A total of 442 patients in the invasive strategy arm underwent angiography and 204 patients (44 percent) underwent revascularization. In the conservative strategy group, 222 patients underwent angiography and 152 (33 percent)had revascularization.

Overall, the death rate 30 days after revascularization was 4.8 percent (17 of 356 patients).

A total of 152 cardiac events (80 deaths and 72 nonfatal infarctions) occurred in 138 patients in the invasive-strategy group, as did 139 cardiac events (59 deaths and 80 nonfatal infarctions) in 123 patients in the conservative-strategy group (P=0.35).

Cumulative rates of death or nonfatal infarction did not differ significantly during long-term follow-up (hazard ratio for the conservative-strategy as compared with the invasive-strategy, 0.87; 95 percent confidence interval, 0.68 to 1.10).

Of the 236 patients assigned to the conservative strategy who did not undergo angiography (52 percent), only 1.3 percent had had a nonfatal infarction or died by 30 days, and 11 percent by 1 year. The mortality was only 1 percent at 30 days and 6 percent at 1 year.

The duration of hospitalization was significantly longer in the invasive-strategy group than in the conservative-strategy group (9.5 vs. 8.2 days, P=0.024).

Interpretation:

Although the 1987 American College of Cardiology-American Heart Association guidelines for coronary arteriography recommended routine coronary angiography for all patients after non-Q-wave infarction, newer guidelines no longer endorse this approach to treatment. The VANQWISH trial was the largest randomized trial of invasive versus conservative management in isoenzyme - confirmed non-Q-wave MI. It was not designed to compare revascularization vs no revascularization, but rather the difference between the two strategies (routine vs. ischemia-driven angiography). Patients at very high risk for ischemic complications were excluded from the study population. The clinical outcomes up to 1 year were similar between the two strategies. The investigators found no evidence that using a routine strategy of early invasive treatment resulted in more expeditious management or shorter hospitalizations. Ischemia-driven angiography appears to be an appropriate management strategy for patients similar to those studied.

References:

1. Journal Am Coll Cardiol 1998;31:312-20. Design and baseline characteristics
2. N Engl J Med 1998;338:1785-92. Final results

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Myocardial Infarction, Isoenzymes, Follow-Up Studies, Coronary Angiography, Creatine Kinase, MB Form, Coronary Disease, Confidence Intervals, Electrocardiography


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