Long-term follow-up with stress echocardiograms of patients with Kawasaki's disease

Patients with a history of Kawasaki's disease (KD), particularly those not treated with intravenous gamma-globulin, are at risk of coronary artery aneurysms and later obstruction. Twenty-eight patients with a history of KD (4 had coronary artery aneurysms) were examined with stress echocardiograms. Fourteen patients received gamma-globulin < or =10 days of the onset, 8 patients received gamma-globulin >10 days and 6 received no gamma-globulin. The mean age at diagnosis was 7.2 +/- 4.1 years; the median follow-up was 8.0 +/- 7.4 years. All tests were negative. Using a binomial model, a power of 0.80, a sensitivity of each test of 80% and assuming uniform risk, the individual rate of failure to detect was <7%. At least 640 patients in each group would be needed to detect a difference of 3.5% vs. 7.0% and 184 in each group would be needed to detect a difference of 1.5% vs. 7.5%. We conclude that the probability of an abnormal stress echo in asymptomatic patients with a history of KD is at most 7% and that a more precise determination of the risk of an abnormal stress echo in KD requires a much larger study.