QUANTIFICATION OF MYOCARDIAL BLOOD-FLOW AND FLOW RESERVE IN CHILDREN WITH A HISTORY OF KAWASAKI-DISEASE AND NORMAL CORONARY-ARTERIES USING POSITRON EMISSION TOMOGRAPHY

Objectives. The purpose of this investigation was to determine whether myocardial blood flow and flow reserve, based on quantitative measure ments derived from positron emission tomographic (PET) imaging, would be globally impaired in children with a previous history of Kawasaki d isease and normal epicardial coronary arteries. Background. Kawasaki d isease is an acute inflammatory process of the arterial walls that res ults in panvasculitis in early childhood. Children with a history of K awasaki disease and normal epicardial coronary arteries were previousl y considered to have normal coronary flow reserve. However, recent stu dies have reported exercise-induced regional perfusion abnormalities o n single photon positron emission tomographic (SPECT) imaging. Methods . We assessed myocardial blood flow and flow reserve at rest and durin g adenosine stress with nitrogen-13 ammonia and PET in 10 children wit h a history of Kawasaki disease and in 10 healthy young adult voluntee rs. All children had acute Kawasaki disease 4 to 15 years before the P ET study. None of the children had epicardial coronary artery abnormal ities at the acute stage of the disease or during follow-up, as assess ed by echocardiography. Results. Rest blood flows normalized to the ra te-pressure product, an index of cardiac work, were similar in both th e patients with Kawasaki disease and healthy adult volunteers (82 +/- 14 vs. 77 +/- 16 ml/100 g per min [mean +/- SD], p = NS). However, hyp eremic blood flows were significantly lower in the patients with Kawas aki disease than in the control subjects (263 +/- 64 vs. 340 +/- 57 ml /100 g per min, p = 0.01), As a result, estimates of myocardial flow r eserve were lower in the patients with Kawasaki disease than in the he althy young adult volunteers (3.2 +/- 0.7 vs. 4.6 +/- 0.9, p = 0.003). In addition, total coronary resistance was higher in the patients wit h Kawasaki disease than in the healthy adult volunteers (33 +/- vs. 24 +/- 5 mm Hg/ml per g per min, p = 0.04). Quantitative analysis of per fusion images demonstrated no evidence of regional perfusion abnormali ties. Conclusions. Children with a previous history of Kawasaki diseas e and normal epicardial coronary arteries exhibit normal rest myocardi al blood flows but reduced hyperemic flows and flow reserve. The abnor mal hyperemic blood hows and how reserve suggest an impaired vasodilat ory capacity, possibly due to residual damage of the coronary microcir culation.