Answering the hard questions about thrombolysis

CMAJ 1998;158:1600

• Letter: Thrombolytics for stroke

First, only 36.3% of patients with acute MI received thrombolysis in this large Quebec cohort. In a similar large European cohort, 36% of patients with acute MI received thrombolysis, although up to 55% met the criteria.¹ In another, smaller Canadian study, 48.9% of patients with acute MI met the criteria for, and received, thrombolysis.² These data suggest a 12% to 19% rate of underutilization of thrombolysis in the Quebec cohort.

Second, the authors found that the strongest factor in delay to thrombolysis was decision-making that involved a cardiologist: the 75th percentile time from hospital arrival to thrombolysis was 32 minutes longer for cardiologists than for emergency physicians. Thus, the emergency physicians gave thrombolytics to 75% of the patients they treated within 78 minutes, whereas cardiologists did so within only 110 minutes. The authors make a convincing argument that this delay might relate to the fact that cardiologists are asked to make decisions in more complex cases. Although this may often be the case, Table 2 shows that fully 46% of the cohort were treated by cardiologists. Could all, or even most, of these cases have been so complex? Furthermore, most of the complex cases would probably appear in the last quartile of the time range and are therefore unlikely to explain the difference in the median or 75th percentile times.

A simple explanation for the delay may be that cardiologists, unlike emergency physicians, are rarely in the emergency department when a patient arrives with acute chest pain. It is easy to imagine how a 32-minute delay could be created by having to wait for the cardiologist to arrive, repeat the examination and decide on therapy. Many studies have shown that thrombolysis is administered significantly more rapidly by emergency physicians, with high rates of appropriateness.² I echo the authors' call to guard against delays associated with consultation. The answer may well be for hospitals, emergency physicians and cardiologists to develop policies jointly, encouraging routine emergency thrombolysis by emergency physicians.

Michael Schull, MD, MSc
Emergency Department
Sir Mortimer B. Davis­Jewish General
Hospital
Montreal, Que.

References

1. European Secondary Prevention Study Group. Translation of clinical trials into practice: a European population-based study of the use of thrombolysis for acute myocardial infarction. Lancet 1996;347:1203-7.
2. Schull M, Battista R, Brophy J, Joseph L, Cass D. Determining appropriateness of coronary thrombolysis in the emergency department. Ann Emerg Med 1998;31(1):12-8.

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