Abstract 2567: Depressed Coronary Flow Reserve in Patients with CHF Secondary to IDC is Associated with Decreased Myocardial Capillary Density
Introduction: Coronary flow reserve (CFR) has been reported depressed in patients with idiopathic dilated cardiomyopathy (IDC) especially in those patients with end stage heart failure. The aim of the present study was to examine the relationship between CFR and capillary density (CD) in patients with IDC.
Methods: CFR was measured in patients with IDC and angiographically normal coronary arteries. Measurements were made with a pressure-temperature sensor-tipped 0.014-inch floppy guide wire placed in the distal portion of the left anterior descending artery. With 3ml of saline at room temperature used as an indicator, by hand injection, thermodilution curves were obtained in triplicate both at baseline and at maximum hyperemia induced by intravenous adenosine. CFR was calculated from the ratio of inverse mean transit times. Right heart biopsies were performed during the same procedure. Histochemical staining with CD-34 was performed, and CD was morphometrically evaluated.
Results: The study population consisted of 14 patients 47±10 years old with a left ventricular ejection fraction of 23±8 % and a mean pulmonary capillary wedge pressure of 21 ± 9 mmHg. There was a close linear relationship between CFR and CD (R2=0.621, p=0.001). Patients with abnormal CFR (CFR≤2) had significantly reduced CD (CFR=1.3±0.29, CD=36.6±15, n=8) compared to patients with normal CFR (CFR=3.9±1, CD= 79±4.7, n=6) p=0.001 .
Conclusions: Patients with congestive heart failure due to IDC and depressed CFR values present significant reduction in myocardial capillary density.