Pharmacologic effects of calcium channel blockers on restenosis

The understanding and control of the healing process after percutaneous tra nsluminal coronary angioplasty (PTCA) and of the: pathogenesis of restenosi s are incomplete. To date, only stent implantation has been shown to succes sfully reduce the rate of restenosis. Calcium channel blockers have positiv e 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 a ssess the effect of calcium channel blockers on restenosis and ischemia. A meta-analysis of five restenosis trials investigating calcium channel block ers demonstrated a 30% reduction in the risk for restenosis. The Coronary A ngioplasty Amlodipine Restenosis Study (CAPARES) is therefore assessing the effect of amlodipine, a long-acting, third-generation calcium channel bloc ker in angioplasty patients. Therapy (amlodipine 5 mg with a forced titrati on to 10 mg once daily, or placebo), is begun 2 weeks before angioplasty an d is continued for 4 months after the procedure. The rationale of CAPARES i s that amlodipine may offer anti-ischemic protection before, during, and af ter 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.