The advantage of thrombolytic therapy is its widespread availability and ease of administration. However, thrombolytic therapy fails to open the infarct-related artery in nearly one-fifth of cases and thus often provides incomplete reperfusion. In contrast, primary PCI has a high rate of reperfusion success, improved clinical outcomes, and few contraindications, but <25% of US hospitals have the means to perform primary PCI, and even fewer provide 24-hour coverage (4).

The Atlantic C-PORT trial randomized 450 patients from 11 community hospitals without on-site cardiac surgery to either thrombolytic therapy or primary PCI for acute myocardial infarction (MI) (5). The primary endpoint was the incidence of the composite of death, recurrent MI, or stroke 6 months after the index MI. Patients treated with primary PCI had a 42% reduction in the primary endpoint compared with those treated with thrombolytics. Women and the elderly had 50% and 40% reductions, respectively, in the primary endpoint as well. Interestingly, outcomes at low-volume centers (fewer than 1 primary PCI/month) had similar outcomes to thrombolytic therapy. Keeley et al. performed a large meta-analysis on 23 trials encompassing 7,700 patients randomized to percutaneous transluminal coronary angioplasty (PTCA) versus thrombolytic therapy (6). Nearly half of the trials invoked the use of coronary stenting and nearly one-third used platelet glycoprotein (GP) IIb/IIIa inhibitors. Only 3% of thrombolytic therapy patients crossed over to primary PTCA, while 0.6% randomized to PTCA crossed over to thrombolytic therapy. Short-term and longterm clinical outcomes are detailed in Figure 18-1. Patients receiving primary PTCA had fewer rates of short-term death (7% vs. 9%; p = 0.0002), nonfatal reinfarction (3% vs. 7%; p < 0.0001), stroke (1% vs. 2%; p = 0.0004), and the combined endpoint of death, nonfatal reinfarction, and stroke (8% vs. 14%; p < 0.0001). The significant reductions in death, nonfatal reinfarction, and the combined endpoint remained regardless of which thrombolytic agent was used. Five trials were analyzed, comparing on-site thrombolytic therapy to emergent transfer for primary PTCA. Despite the delays associated with patient transfer to a PCI facility (mean time, 39 minutes), primary PTCA was associated with significant reductions in nonfatal reinfarction, total stroke, and the combined endpoint (Fig. 18-2). In patients with cardiogenic shock, PCI appeared to have its greatest mortality benefit with an absolute 9% reduction in 30-day mortality, as reported in the SHOCK trial (7).

As the time delay for performing PCI increases, the clinical benefits associated with PCI over thrombolytics diminish (Fig. 18-3). This is particularly true in regard to mortality when delays are in excess of 60 minutes (8). In addition, the improved mortality benefit with PCI diminishes when PCI is performed in low-volume centers, where delays in door-to-balloon times are more likely to occur (9). Thrombolytic therapy is similarly limited in its efficacy as the duration from symptom onset to presentation increases, though a benefit still may be seen up to 18 hours of symptom onset (10, 11). Furthermore, there are a number of absolute and relative contraindications to thrombolytic therapy that the clinician must be mindful of before administering to a patient (Table 18-1). In contrast, a few contraindications exist for PCI such as patient refusal or when the patient’s risk for complication may be considered too high by the caring physician.