Research shapes optimal coronary interventions

January 17, 2006

New research conducted in Europe may guide strategies that determine the best time and optimal tools for coronary interventions. Results from one multicenter trial indicate that early intervention is better than a wait-and-watch policy for patients with partial vessel occlusion. Meanwhile, a Swiss team has published data questioning the cost-effectiveness of drug-eluting stents for revascularization.

New research conducted in Europe may guide strategies that determine the best time and optimal tools for coronary interventions. Results from one multicenter trial indicate that early intervention is better than a wait-and-watch policy for patients with partial vessel occlusion. Meanwhile, a Swiss team has published data questioning the cost-effectiveness of drug-eluting stents for revascularization.

Rupture of coronary plaques may not completely block vessels, although patients can still suffer acute chest pain. Deciding whether and when to repair these partially occluded vessels has been a subject of considerable debate, according to Dr. Keith A. Fox, chief of cardiology at the University of Edinburgh. He expects data from a randomized trial involving 1810 patients from 45 U.K. hospitals to settle the matter (Lancet 2005;366:914-920).

In the trial, patients presenting with non-ST elevation acute coronary syndrome, typified by plaque disruption, thrombus formation, and microembolization, received either early intervention (895 patients) or conservative management (915). This translated into almost-immediate angiography and revascularization versus ischemia- or symptom-driven angiography.

Rates of death or nonfatal myocardial infarction were similar for both groups at one-year follow-up. After five years, however, far fewer patients randomized into the early intervention group died or suffered a heart attack. The researchers concluded that prompt treatment prevented 3.5 such adverse outcomes in every 100 patients.

The five-year data show that hazards associated with intervention are offset by long-term benefits, Fox said. This conclusion could not be drawn from previous studies that considered clinical outcomes after only one or two years.

"All of these patients, apart from the lowest risk group, will need to have angiography with a view to intervention and revascularization. These are the definitive, long-term data," he said.

A separate analysis comparing the cost-effectiveness of drug-eluting and bare metal stents suggests interventionists should stick with their existing practices when it comes to choosing technology.

Dr. Matthias Pfisterer, a professor and head of cardiology at the University of Basel in Switzerland, assessed clinical outcome and treatment costs for 826 consecutive patients requiring percutaneous coronary intervention and stenting.

Patients were randomized to receive either drug-eluting (545 patients) or bare metal (281) stents (Lancet 2005; 366:921-929).

The team recorded an outcome of cardiac death, myocardial infarction, or target vessel revascularization after six months in 39 patients fitted with drug-eluting stents (7.2%) and in 34 patients who received the bare metal stents (12.1%).

Researchers concluded that while drug-eluting stents led to decreased follow-up costs, the high price of the stents outweighed that benefit. Improved outcomes in these cases would come at a cost of nearly $35,000 per patient. Cost-effectiveness improved, however, when considering only high-risk patients.

The investigation's conclusions are already guiding stent choice at the University Hospital of Basel, Pfisterer said. The study is also being examined by agencies in the U.K. and the Netherlands responsible for developing clinical practice guidelines.