Areas of Uncertainty
Although the use of primary PCI is widespread, some issues are unresolved. First, the administration of a fibrinolytic agent or platelet glycoprotein IIb/IIIa inhibitor or both before PCI — called a facilitated intervention — is based on the hypothesis that immediate pharmacologic therapy followed by prompt PCI will cause a faster and more complete restoration of flow in the infarct-related artery than PCI alone. A meta-analysis of trials comparing these two procedures concluded that patients with myocardial infarction with ST-segment elevation who received facilitated PCI were more likely to have a patent infarct-related artery at the time of initial coronary angiography than those receiving PCI alone. Despite this finding, patients receiving facilitated intervention had increased rates of nonfatal reinfarction, urgent target-vessel revascularization, stroke, and death, as compared with patients undergoing only PCI. The increased rate of adverse events with facilitated intervention was seen predominantly among patients receiving fibrinolytic therapy. At present, it is unknown whether facilitated PCI with the use of only platelet glycoprotein IIb/IIIa inhibitors is superior to primary PCI alone.
Second, the choice between the use of fibrinolytic therapy and the transfer of the patient to another facility for primary PCI depends on the patient’s clinical characteristics and the rapidity and efficiency of the transfer. Although several randomized studies comparing on-site fibrinolytic therapy with transfer for primary PCI showed better short-term outcomes in patients transferred to another hospital for PCI, these studies were conducted in highly efficient transfer networks. In the United States, such transfers often are inefficient, and unacceptable treatment delays occur. Since most Americans live near a facility proficient in the performance of primary PCI, they could receive this treatment if an organized and efficient system of triage and transfer were available.
Third, some patients with myocardial infarction with ST-segment elevation who undergo primary PCI are found to have severe multivessel coronary artery disease. After the urgent restoration of antegrade flow in the infarct-related artery, the management — medical, percutaneous, or surgical — of the care of these patients, including its timing, is uncertain.