Coronary Dysfunction in Developing Myocardial Damage in Congenital Heart Diseases

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It has been reported, in adulthood, that myocardial ischemia in the hypertrophic heart was an exacerbation factor to progressive myocardial damage. However, there have been few studies on the coronary hemodynamics in the congenital heart diseases with significant myocardial overload. To assess the coronary hemodynamics in the congenital heart diseases, we examined the coronary flow-velocity dynamics using an intracoronary Doppler guide wire at rest and during the adenosine triphosphate (ATP) -induced hyperemic responses in patients with cyanotic congenital heart diseasesThis study group consisted of 28 Japanese patients (18 males and 10 females) (mean ages : 5.12 ± 4.9 years) who were undergoing the routine cardiac catheterization for the evaluation of pre- (16 patients ; 10 TOF, 4 DORV, 2 TGA) and post-operative (12 patients ; 9 TOF and 3 DORV) CHDs. As we previously reported, coronary flow-velocity variables were measured using a 175-cm-long, 0.018-inch flexible, steer able angioplas … More tic guide wire with a 12-mHz piezoelectric ultrasound transducer integrated into its tip (FloWireR, Cardio metrics, Inc., Mountain View, California). The coronary flow reserve (CFR), which was an indicator of the potency in the micro vascular bed, was assessed by calculating the quotient of the peak hyperemic average peak velocity (APV) after intracoronary injection of ATP and the baseline APV. Age-matched control data reported previously were used as reference values for comparisons of coronary flow patternsIn the pre-operative group, significantly higher DSVR values were noted in 69 % of 16 patients in the LAD and in 81 % in the RCA. A significant reversed flow signal in the systolic phase were also detected in 11(75 %) of 16 patients in the LAD, and 13(81 %) in the RCA. On the other hand, in the post-operative group, significantly higher DSVR values were detected in only 1(8 %) of 12 patients in the LAD, and none in the RCA. A reversed flow signal was noted in only 1(8 %) in the LAD and 2(17 %) in the RCA. In the pre-operative group, significantly lower CFR values were noted in 9(56 %) of 16 patients in the LAD, and in all patients (100 %) in the RCA. In the Posto-perative group, on the other hand, a significant reduction in CFR was noted in only 3(25 %) of 12 patients in both of the LAD and the RCA. The post-operative periods were shorter (< 2 years) in the patients with a reduced CFR in each vessel, and longer in the Patients with a normal CFR. AIn this study, abnormal coronary flow profile and reduced CFR noted in all of the pre-operative patients indicate a significant increase in coronary resistance with a reduced dilatory potency of the small coronary artery or a decrease in myocardial compliance in the systolic Phase, developinging in myocardial ischemia or irreversible myocardial damage. In management and surgical operation of the congenital heart diseases with significant myocardial overload, it is necessary to take into careful consideration the secondary coronary dysfunction for preventing myocardial ischemia as an exacerbation factor to irreversible myocardial damage. Less