New frontiers and unresolved controversies in percutaneous coronary intervention

Percutaneous coronary intervention (PCI) has become a key modality of therapy of patients with coronary artery disease. However, with the exception of acute coronary syndromes, there is as yet no conclusive evidence from randomized controlled trials that PCI improves survival and outcome compared with optimal medical therapy. Randomized trials comparing PCI and coronary artery bypass grafting in patients with stable coronary artery disease conducted before stenting showed superiority of the surgical approach. Early results from stent trials continue to indicate better symptom relief and less need for repeat intervention with the surgical approach, although myocardial infarction and mortality are similar with the 2 revascularization modalities. In the setting of acute coronary syndromes, however, recent trials suggest superiority of an aggressive approach, including PCI, compared with a conservative strategy of medical therapy only. This benefit extends to patients with acute ST-elevation myocardial infarction, including those with shock. In the latter setting, mortality remains high and novel approaches to protect myocardial metabolism and improve perfusion will be needed to further improve survival. The role of revascularization in patients with completed myocardial infarction and persistently occluded arteries is much less clear. Although the late open artery hypothesis is widely accepted and interventional cardiologists routinely open late infarct-related coronary occlusions, the available evidence to justify this strategy is weak. New devices, such as thrombectomy devices in thrombus-laden lesions and drug-eluting stents, offer promise, although all lack the degree of proof of benefit and safety typically required of new pharmaceutical agents. As new technologies and therapies with the potential to improve outcomes and decelerate the atherosclerotic process are developed, it will be important for investigators and industry to collaborate in incorporating these advances into ongoing and new trials testing the efficacy of PCI in all settings.