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Chapter (5)

clinical trials

Chronic Stable Angina (Non-Acute CAD)

COMPARISON OF MEDICAL THERAPY VERSUS INTERVENTIONAL APPROACH (PCI)

Summary Of Results
Important Recent Trials

SUMMARY OF RESULTS

The following are summary of results and metanalysis of seven randomized controlled trials:

- Relief of angina

Single vessel disease: PCI leads to greater reduction in angina than medical treatment (ACME Trial), but at the cost of more coronary artery bypass grafting (CABG).
Multivessel Disease: No difference between PCI and medical therapy in freedom from angina, increase in exercise duration, or improvement in an overall quality of life score (ACME trial).

- Fatal and Nonfatal Myocardial Infarction:

No significant difference between PCI and medical therapy, although, the trend was favouring the medical approach (Figure 5-1)

- Effects on Survival

PCI offered no overall significant mortality benefits compared to medical therapy.

- Need for PCI

No significant difference though trend favours medical treatment.

- Need for CABG

Patients on medical treatment required less CABG than those receiving PCI. There was a significant difference between the two approaches in favour of medical therapy.

Figure (5-1) Comparison of medical therapy vs interventional approach (PCI) in patients with non-acute CAD.Lancet 2001.

IMPORTANT RECENT TRIALS

· RITA-2 (1997)

1018 patients followed for average 32 months.
After 2-7 years median follow-up, the incidence of deaths or MI was significantly lower in the medically treated group (3.3 versus 6.3 percent) due primarily to more early non fatal infarctions related to PCI.
At seven years, the incidence of death or MI was comparable for both groups.
Improvement in angina and total treadmill exercise time favoured PCI initially particularly in patients who had more severe angina, however, these differences did not persist at three years.

· AVERT trial (1999)

341 stable low risk patients followed for average of 18 months, comparing aggressive lipid therapy (large dose of atorvastatin 80 mg/day) versus PCI.
The time to a first ischemic event was significantly longer in the atorvastatin group, and there was a trend toward fewer cardiac events.
Need for CABG was significantly less in atorvastatin group.
No significant difference between the two groups in fatal and nonfatal MI or total mortality.

TIME trial (2003)

282 elderly patients (>75 years) with refractory angina (Canadian class 2 or higher despite treatment with 2 or more antianginal drugs) comparing optimal medical therapy versus invasive revascularization (PCI or CABG).
Improvements in angina and quality of life: early difference favouring invasive therapy disappeared after one year follow-up.
Differences in one year mortality, fatal and non fatal MI were not significant between the two groups.
Invasive approach carries an early intervention risk, while medical treatment has an almost 50% chance of later hospitalization and revascularization.

FACTORS FAVOURING INVASIVE APPROACH (REVASCULARIZATION)

Poor left ventricular function.
Strongly positive stress test.
Large perfusion defect on myocardial perfusion imaging (ischemia of > 10 percent of total myocardium).
Left main disease (CABG).
Three vessel disease (CABG).
Symptoms refractory to medical therapy.
Two vessel disease including the proximal LAD (CABG versus PCI).

Author suggests that aggressive optimal medical therapy can ameliorate angina and myocardial ischemia in majority of patients and choice of continued medical treatment versus invasive approach depends beside patient risk profile and response to medical therapy upon availability of resources and access to coronary angiography.