Interventional cardiology--promises and challenges

The current explosion in coronary stent use for the treatment of coronary artery disease has helped to better define who really benefits from coronary stenting. It is clear that plain old balloon angioplasty can be at least as efficacious as stenting in certain patient groups. Patients with reference vessel diameter of < 2.5 mm, a small post-stent minimal lumen diameter, lesion length > 30 mm, diabetes mellitus and end-stage renal failure--all associated with a high incidence of diffuse in-stent restenosis--should not be stented routinely. The judicious use of stents in percutaneous revascularization will improve patient outcomes and decrease cost. The progress that has been achieved in coronary stent designs has led to many new questions, such as which patients benefit the most from stenting and whether adjunctive therapies or stent coatings will effectively prevent restenosis. Despite the advances in stent/balloon technology, antiplatelet agents, and interventional operator skill, the problems of in-stent restenosis remain. Novel therapeutic strategies for the management of severe coronary artery disease are evolving rapidly. Radiation therapy shows promise on this front. This therapy may reduce rates of restenosis by inhibiting smooth muscle proliferation and migration. However, important issues regarding the type of radiation and the matter of edge-restenosis are yet to be resolved, and the results of ongoing prospective randomized trials should provide valuable information on the efficacy of this modality. Patients with severe, non-revascularizable coronary artery disease and debilitating symptoms represent another frustrating clinical problem. PMR performed in the cardiac catheterization laboratory may improve symptoms of angina in patients with end-stage coronary artery disease. The early results are propitious. Among patients who have undergone this procedure 80-90% have improved from class IV (the most severe chest pain) to class I or II, enabling them to live relatively normal lives. Most investigators believe that PMR may be used only for those who are unsuitable candidates for percutaneous or surgical revascularization. Finally, gene therapy, by stimulating angiogenesis and improving coronary collateral development, may prove to be the most optimal treatment. Each of these strategies is currently under active investigation to confirm the results of the pilot studies, identify patient subgroups likely to respond to therapy, and determine long-term safety. Together with its challenges, the future of interventional cardiology is indeed bright.