Abstract 699: Intracoronary Infusion Of Bone Marrow-derived Progenitor Cells In Patients With Non-ischemic Dilated Cardiomyopathy Is Associated With An Increase Of Coronary Blood Flow In The Target Vessel
We recently could demonstrate that intracoronary administration of bonemarrow-derived progenitor cells (BMC) is associated with improved target area contractility and enhanced cardiac function in patients (pts) with nonischemic dilated cardiomyopathy (DCM). The influence of coronary microvascular dysfunction on development and progression of DCM in the absence of epicardial artery atherosclerosis has been demonstrated in experimental studies. Therefore, to get insights into potential mechanisms of BMC therapy in pts with DCM, we performed a substudy of the TOPCARE-DCM trial, assessing coronary blood flow (CBF) by intracoronary Doppler measurements.
Methods 13 pts (age 31 to 64 yrs; ejection fraction 28 ± 14 %) were included. A mean number of 353 ± 119 * 106 BMC were infused into the left anterior descending (LAD) artery using the stop-flow technique. Doppler-derived CBF velocities in the target (LAD) as well as in a reference vessel (left circumflex artery, ref) were obtained at baseline prior to BMC administration and at 3 months’ angiographic follow up (FU).
Results Heart rate, blood pressure and coronary artery lumen diameter did not differ between initial and FU measurements. Basal coronary vascular resistance (VR) decreased after 3 months in the target and in the ref vessel (target 6.32 ± 2.43 vs 5.43 ± 2.28, p < 0.01; ref 6.72 ± 2.15 vs 5.41 ± 1.94 mmHg*s/cm, p = 0.03). In contrast, adenosine-induced minimal VR decreased only in the target vessel but not in the ref vessel (target 1.53 ± 0.60 vs 1.31 ± 0.65, p < 0.01; ref 1.60 ± 0.45 vs 1.49 ± 0.45 mmHg*s/cm, p = ns). Due to the selective decrease in adenosine-induced minimal VR of the target vessel, the coronary flow reserve normalized for the ref vessel increased from 1.0 ± 0.2 to 1.2 ± 0.3 (p < 0.05). Likewise, the CBF increased in the target vessel (from 48 ± 18 to 62 ± 25 ml/min, p = 0.02), but remained unchanged in the ref vessel (from 40 ± 21 to 48 ± 18 ml/min, p = ns).
Conclusions In pts with nonischemic DCM, intracoronary BMC infusion is associated with a significant improvement in microvascular function of the target area. Whether improved microvascular function as a potential mechanism underlying the beneficial effects of BMC is causally linked to an improved cardiac contractile function has to be analysed in larger studies.