Initial Stent Implantation for Stable Coronary Artery Disease

A new meta-analysis comparing stent implantation and medical therapy versus medical therapy alone for patients with stable coronary artery disease (CAD) found that initial stent implantation did not appear to offer a benefit in terms of preventing death, nonfatal myocardial infarction (MI), unplanned revascularization, or angina when compared with medical therapy alone. These findings were published in Archives of Internal Medicine [2012;172(4):312-319].

Previous meta-analyses have been conducted to assess whether percutaneous coronary intervention (PCI) for patients with stable CAD improves patient survival; however, often these analyses have included data from studies conducted when balloon angioplasty or out-of-date medical therapies were used. 

In this analysis, researchers reviewed data from randomized clinical trials that compared the combination of initial stent implantation and medical therapy with initial medical therapy alone to determine what impact the treatment methods had on death, MI, unplanned revascularization, and persistent angina on patients with stable CAD.

Researchers conducted an electronic search to identify 8 trials conducted between 1997 and 2005 that met the study requirements. To be included, studies must have been prospective, randomized trials that compared the 2 treatment methods, had a record of stents being used in at least 50% of trial PCI procedures, and reported individual outcomes of death and nonfatal MI at a minimum follow-up period of 1 year. Of the 8 studies used, 3 enrolled stable patients after MI, whereas 5 enrolled patients with stable angina or ischemia on stress testing.

The trials included in the analysis represented a total of 7229 patients, 3617 of whom were randomized to receive stent treatment and medical therapy and 3612 who were randomized to receive medical therapy alone. The mean weighted follow-up time was 4.3 years.

The clinical outcomes assessed during the meta-analysis were death from any cause (unless only cardiac death was reported in the trial), nonfatal MI or reinfarction for studies that enrolled post-MI patients, unplanned revascularization, and persistent angina.

According to the results of the analysis, researchers found there was no evidence that initial stent implantation provided a benefit in preventing death when compared with those patients who initially received medical therapy alone. Based on the results, 8.9% of those in the stent arms and 9.1% of those in the medical therapy arms died during the trials. The calculated odds ratio (OR) for initial stent implantation versus medical therapy was 0.98 (95% confidence interval [CI], 0.84-1.16; P=.83).

In addition, there was no evidence that initial stent implantation provided a significant benefit in preventing nonfatal MI or unplanned revascularizations. Nonfatal MIs were reported in 8.9% of patients in the stent groups and 8.1% of the patients in the medical therapy groups, and the OR for nonfatal MIs for stent implantation compared with initial medical therapy was 1.12 (95% CI, 0.93-1.34; P=.22). The event rates for unplanned revascularizations were 21.4% for stent patients and 30.7% for medical therapy patients. The OR for unplanned revascularizations for the stent implantation groups compared with the initial medical therapy group was 0.78 (95% CI, 0.57-1.06; P=.11).

Finally, researchers reported that 29% of patients experienced persistent angina in the stent groups compared with 33% in the medical therapy group. They calculated an OR for the stent group compared with the medical therapy group of 0.80 (95% CI, 0.60-1.05; P=.10).

According to the authors of the meta-analysis, there were several limitations to the study, including that the analysis was conducted using pooled results from each individual trial not patient-level data. In addition, the data only came from randomized clinical trials not from clinical practice, variables such as age or sex may have been related to the outcomes, and there may have been undetected benefits or harms to courses of therapy.