Abstract 3590: Reduced Coronary Flow Reserve is a Predictor of Cardiac Events in Patients with Non-ischemic Cardiomyopathy as well as in those with Cardiac Amyloidosis
Background: To elucidate the significance of impaired microcirculation in non-ischemic cardiomyopathy (NICM), we examined the relationship between clinical outcome and coronary flow reserve (CFR) in 49 NICM patients (33 male and 16 female patients, age: 59±3) with low LVEF (<5%).
Methods: After confirming absence of significant stenosis in coronary arteriogram, CFR was measured with Doppler flow wire inserted into left anterior descending branch in the NICM patients, that consisted of 38 dilated cardiomyopathy (DCM), 6 hypertensive heart disease (HHD), and 5 cardiac amyloidosis (CA).
Results: In CA, CFR was invariably reduced (1.6±.2). In DCM or HHD, the value of CFR varied from low to high, but it was mostly maintained (3.0±7 and 3.0±.0, respectively). In the patients with attenuated CFR (<2.5, n=19), five-year survival and cardiac event free rate were significantly lower (P<0.005 and P<0.001, respectively) than the patients with normal CFR (Figures A and B⇓). These tendencies were obviously affected by the unfavorable outcome of the CA patients whose CFR was remarkably reduced. However, even after excluding the CA patients, the attenuated CFR was still associated with lower event free rate (P<0.01, Figure B⇓). The value of CFR was not correlated with other prognostic parameters of heart failure such as LVEF or BNP. Histopatho-logical examination of endomyocardial specimens showed perivascular fibrosis in the patients with attenuated CFR.
Conclusions: Impaired CFR predicts future cardiac events in DCM or HHD, as well as CA. Measurement of CFR in NICM serves to identify the involvement of impaired microcirculation in the pathogenesis of their cardiac condition.