Patients with severe coronary artery involvement after Kawasaki disease (KD) require long-term systemic anticoagulation. We sought to compare our experience with thrombotic coronary artery occlusions, safety profile, and degree of coronary artery aneurysm regression in KD patients treated with low molecular weight heparin (LMWH) versus warfarin. Medical records of all KD patients diagnosed between January 1990 and April 2007 were reviewed. Of 1374 KD patients, 38 (3%) received systemic anticoagulation, 25 patients received LMWH from diagnosis onward, 12 of whom were subsequently switched to warfarin, and 13 received warfarin from onset. The frequency of thrombotic coronary artery occlusions was similar between drugs. Severe bleeding was more frequent in patients on warfarin, but minor bleeding was more frequent for patients on LMWH. Patients on warfarin were at greater risk of underanticoagulation or overanticoagulation (defined as achieving an anti-activated factor X level or an international normalized ratio below or above target level) than patients on LMWH (P < 0.05). Maximum coronary artery aneurysm z-scores diminished with time for patients on LMWH (P = 0.03) but not for those on warfarin (P = 0.55). This study suggests that LMWH is a potentially viable alternative for patients, especially young ones, with severe coronary artery involvement after KD.

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Background: Previous studies on recurrence of Kawasaki disease (KD) have mostly been limited to Japan, which has an incidence of KD 8-10-fold higher than North America. The aim of the present study was to determine the rate of KD recurrence for patients in Ontario, to identify factors potentially associated with increased odds of recurrence, and to compare the clinical course and outcomes of index and recurrent KD episodes. Methods: Review was undertaken of all patients with recurrence of KD identified in Ontario, Canada, from 1995 to 2006. All patients with recurrence of KD (defined as at least three clinical signs of KD in addition to fever 35 days), presenting 314 days after the return to baseline from the index episode were included. Results: A total of 1010 patients were followed for 5786 patient-years. During this period a total of 17 recurrent episodes in 16 patients were identified at a median of 1.5 years after the initial episode (2 weeks-5 years). Rate of recurrence of KD was 2.9 episodes/1000 patient-years, which is higher than the expected annual incidence of KD in the same age group (26.2/100 000 per year). No factors associated with increased risk of recurrence were identified, perhaps due to the small number of events. Clinical course and outcomes of the index and recurrent KD episodes were similar. Conclusions:A previous history of KD should increase the index of suspicion for future episodes of KD to allow for rapid recognition, treatment and to achieve optimal outcomes.Key words coronary artery abnormalities, genetics, Kawasaki disease, recurrence.Recurrence after Kawasaki disease (KD) is a well-established phenomenon. 1 Recurrence of KD is thought to affect approximately 4% of children who have had KD in Japan.2 Populationbased studies conducted in the early 1980s have established the prevalence of recurrence of KD in the USA at <1%; these estimates have not been re-evaluated since. 3,4 Estimates have also shown that the risk of having a second episode of KD for children with a previous history of KD is higher than the risk for children in the general population of having an initial episode of KD.