Abstract 156: Serial Evaluations of Coronary Artery Abnormalities in Kawasaki Disease Patients Should Include Assessment for the Development of Luminal Myofibroblastic Proliferation and Chronic Thromboses: a Preliminary Echocardiographic Study

Abstract

Introduction: We recently reported that luminal myofibroblastic proliferation (LMP) is an active process of smooth muscle-cell derived myofibroblasts and their matrix products that can cause progressive coronary artery (CA) stenoses in KD patients. Serial echocardiography to assess for high risk CA changes, with periodic cardiac functional assessments in selected patients, is the current standard of care for monitoring patients with CA abnormalities. Monitoring for LMP/chronic thromboses is not routinely performed. Hypothesis: We hypothesized that echocardiographic images from KD children with severe CA abnormalities could suggest the presence of LMP and/or chronic thromboses, indicating the potential for progression to CA stenoses. Methods: We reviewed echocardiographic studies from a convenience sample of 28 KD patients with multiple aneurysms/giant aneurysms, to determine whether LMP and/or thrombosis could be identified on serial imaging. Results: In 12 of the 28 patients, images were highly suggestive of LMP and/or thromboses. This could only be assessed in the proximal segments of the left main, circumflex, left anterior descending and right CAs. Detection was enhanced by optimizing the depth and sector width for the coronary artery segment of interest and use of magnification on the review station. Variations in echocardiographic techniques such as low frequency probes, harmonics, persistence, excessive compress or low gain settings made the assessment difficult. 4 patients in this cohort required CA bypass and 1 died from myocardial infarction due to progressive LMP. Distal vessel occlusion could not be visualized by echocardiography. Conclusions: Images highly suggestive of LMP/chronic thromboses were evident in at least a third of patients with severe CA disease, including one patient who died of progressive LMP stenosis documented at autopsy. Echocardiography could not distinguish between LMP and chronic thrombosis as the cause of CA stenoses. Our study highlights the need for improved serial imaging for ongoing LMP/thromboses in AHA risk group IV. Patients with these complications may require more frequent cardiac functional assessments than are routinely recommended, to avoid adverse outcomes.