Abstract 3416: Impaired Microvascular Function as a Predictor of Improvement in Patients with Chronic Post-Infarction Heart Failure Receiving Intracoronary Progenitor Cells - Results of the TOPCARE-CHD Doppler Substudy
Coronary microvascular dysfunction contributes to progressive left ventricular remodelling and poor prognosis in patients with post-infarction heart failure. Since the intracoronary administration of progenitor cells may improve microvascular dysfunction and increase neovascularization, we assessed coronary blood flow regulation in a subgroup of patients with post-infarction heart failure within the randomized TOPCARE-CHD trial.
Results: In a total of 40 patients, coronary blood flow hemodynamics were measured by intracoronary Doppler (Flowire®) in the target vessel of cell administration as well as in a reference vessel at the time of progenitor cell therapy and at 3 month follow-up. In the overall patient population, adenosine-induced coronary flow reserve (CFR) was 3.41±0.98 in the target vessel at baseline, and did not change significantly at follow-up. However, in patients with an impaired CFR at baseline (< 3), CFR improved from 2.4±0.5 to 3.1±0.8 at follow-up (+0.7±0.9, p=0.007), whereas CFR remained unchanged in the reference vessel, . Patients with an increase in maximal vascular conductance capacity at follow-up (n=18) did not differ with respect to age (59 yrs), time since the last MI (36 months) or baseline LVEF (44±10%) from those without (n=22). However, patients with improved microvascular function at follow-up demonstrated a strong trend towards elevated baseline adenosine-induced minimal vascular resistance indices (VRI 1.78±1.4 vs. 1.33±0.79; p=0.08), suggesting an impaired maximal vasodilator capacity. Importantly, in patients treated with bone marrow-derived progenitor cells, the reduction in adenosine-induced minimal VRI was correlated with increased numbers of infused BMC (r = −0.49, p=0.03).
Conclusion: Impaired microvascular function as evidenced by a reduced maximal vasodilator capacity predicts improvement in coronary vascular conductance capacity after intracoronary progenitor cell administration in patients with chronic post-infarction heart failure.