Rapid angioplasty has been demonstrated to be superior to fibrinolysis in the treatment of patients with acute myocardial infarction; however, immediate angioplasty is available in only a limited number of specialized centers. A limitation of angioplasty in most cases of heart attack is the required transportation from a local hospital to an angioplasty referral center. This delay in the initiation of treatment might mitigate the advantages of angioplasty. Andersen and colleagues conducted a randomized trial comparing fibrinolysis at a local hospital with transport to a specialized center for primary angioplasty.
This study enrolled patients from 24 local hospitals and five specialized treatment centers that served 62 percent of the Danish population. The authors initially screened 4,278 patients who had myocardial infarction. Of these, 1,129 patients were randomized at referral hospitals. Exclusion criteria included any contraindication to fibrinolysis, fibrinolytic therapy in the past 30 days, left bundle branch block, nonischemic heart disease, acute myocardial infarction, pulseless femoral arteries, renal failure, and nonischemic heart disease associated with a life expectancy of less than 12 months.
At presentation to the local hospital, patients were assigned randomly to fibrinolysis with alteplase or transport to a catheterization laboratory for angioplasty. All patients received aspirin, intravenous beta-blocker therapy, and heparin. A platelet glycoprotein IIb/IIIa-receptor blocker was administered at the discretion of the treating physician. The average duration of time between onset of infarction symptoms and randomization at the local hospital was about two hours. For patients randomized to angioplasty, transport to the catheterization laboratory took an average of 67 minutes, with 96 percent of patients arriving in less than two hours. A small portion of patients developed arrhythmias during transport, and one patient died shortly after arrival because of refractory ventricular fibrillation.
Angioplasty was performed in 87 percent (706 patients) of those randomized to transport and cardiac catheterization. The most common reasons that balloon inflation was not performed after angiography were normal coronary arteries or a decision that medical treatment was “the best initial strategy.”
Reinfarction within 30 days of treatment was reduced significantly in patients who received transport for angioplasty (1.9 percent) compared with those who received fibrinolysis (6.2 percent). There was a nonsignificant trend toward fewer overall deaths with angioplasty (6.5 percent) versus fibrinolytic therapy (8.5 percent). Death was much more likely (24.2 percent) among the subgroup with reinfarction than in those without recurrent ischemia (6.5 percent). The incidence of disabling stroke was low and similar between the angioplasty and fibrinolysis groups (1.6 and 2.0 percent, respectively).
The authors conclude that transport to a specialized center for angioplasty is superior to fibrinolytic therapy delivered at a local hospital for treatment of myocardial infarction, as long as transport time does not exceed two hours.
editor’s note: An accompanying editorial1 notes that several other studies have demonstrated that transport for angioplasty is better than locally administered fibrinolysis, in terms of reduced rates of reinfarction and improvements in overall death rates and incidence of stroke. The average delay for transport in these studies was 43 minutes. The editorial author advocates transfer for angioplasty whenever the expected transfer delay will be less than one hour, if infarction symptoms have been present for more than three hours (i.e., fibrinolysis is less effective), or when fibrinolytic therapy is contraindicated or not successful.1
This call for wider use of angioplasty has to be balanced with the realization that the benefits, while statistically significant, do not have large absolute differences in outcome compared with fibrinolysis. A combined review2 of 23 trials comparing fibrinolytic therapy with angioplasty within the same referral center showed death rates decreasing from 9 to 7 percent, reinfarction dropping from 7 to 3 percent, and a slight decrease in stroke from 2 to 1 percent.—B.Z.