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Tuesday, March 27, 2007

The COURAGE trial-fewer PCIs down the road for stable angina

The biggest news from the American College of Cardiology meeting in New Orleans(March 2007) has to be the results of the COURAGE trial. This trial compared optimal medical therapy with the combination of medical therapy plus PCI for stable angina patients and medical therapy did just as good. This lead to headlines across the news channels proclaiming that many angioplasties are unnecessary.Full text of the report and a commentary is available from the New England Journal web site for free.

It is important to look at who was not included in this trial:

Patients with very severe angina (CCS stage iv-meaning rest angina or angina brought on by any physical activity)
Patients with very positive stress tests (meaning st changes in stage 1 and/or hypotension brought on by the exercise)
ejection fraction less than 30%
history of revascularization in the previous six months.

Patients had to have at least one epicardial coronary artery with 70% stenosis plus objective evidence of myocardial ischemia to be eligible for the trial.

The study showed no difference in mortality or myocardial infarction in the 4.6 years of observation and was consistent with earlier,smaller trials that suggested no mortality benefit to PCI but perhaps greater relief of anginal symptoms.

I found the following sentence helpful in trying to understand what may be the relevant pathophysiology:

"Unstable plaques that lead to myocardial infarction are not necessarily severely stenotic and severely stenotic plaques are not necessarily unstable ."

While the severely stenotic plaques may be a marker for the unstable variety being present elsewhere in the coronary circulation it is the latter that typically causes the myocardial infarction or acute coronary syndrome so that dilating the former may relieve angina symptoms but is not likely to prevent infarcts.On the other hand, medical therapy is thought to treat all of the coronary arterial tree and may make unstable plaques less likely to cause trouble.

PCIs will be continued to be recommended for many acute coronary syndromes and for anginal patients whose symptoms resist medical therapy but there are bound to be fewer PCIs done for stable anginal patients because of this trial.