Pharmacologic effects of calcium channel blockers on restenosis.

The understanding and control of the healing process after percutaneous transluminal coronary angioplasty (PTCA) and of the pathogenesis of restenosis are incomplete. To date, only stent implantation has been shown to successfully reduce the rate of restenosis. Calcium channel blockers have positive effects on a number of processes that may be associated with restenosis, including reduction of platelet aggregation, minimization of vasospasm, and inhibition of mitogens. Clinical trials have therefore been performed to assess the effect of calcium channel blockers on restenosis and ischemia. A meta-analysis of five restenosis trials investigating calcium channel blockers demonstrated a 30% reduction in the risk for restenosis. The Coronary Angioplasty Amlodipine Restenosis Study (CAPARES) is therefore assessing the effect of amlodipine, a long-acting, third-generation calcium channel blocker in angioplasty patients. Therapy (amlodipine 5 mg with a forced titration to 10 mg once daily, or placebo), is begun 2 weeks before angioplasty and is continued for 4 months after the procedure. The rationale of CAPARES is that amlodipine may offer anti-ischemic protection before, during, and after angioplasty, may have more beneficial effects on restenosis and various clinical end points than calcium channel blockers used in previous trials, and may improve the long-term outcome of PTCA therapy.