Impaired acute collateral recruitment as a possible mechanism for increased cardiac adverse events in patients with diabetes mellitus

Background The mortality of coronary artery disease is increased in diabetic patients. An impaired collateral function is considered a possible explanation. This study should assess the influence of diabetes on collaterals by direct invasive assessment of collateral function. Methods In 90 consecutive patients with a chronic coronary occlusion (TCO) of >2 weeks duration a recanalization was done. Thirty patients with diabetes (33%) were compared with 60 (67%) without diabetes. Blood flow velocity and pressure were measured distal to the occlusion by intracoronary Doppler and pressure wires before PTCA, and again after PTCA during a final balloon reocclusion to assess acute recruitment of collaterals. Resistance indexes for cotlaterals (R-Coll) and peripheral microcirculation (R-p) were calculated. Results The R-Coll (diabetics: 8.1+/-6.8 vs nondiabetics: 8.7+/-6.7 mmHg cm(-1) s(-1); p=0.68) and R-p (5.6+/-4.2 vs 6.6+/-3.8mmHgcm(-1) s(-1) p=0.30) were similar in diabetic and nondiabetic patients before recanalization. During balloon reocclusion both R-Coll and R-p increased. This increase was significantly more pronounced in diabetic than in nondiabetic patients in TCOs <3 months duration. In TCOs of longer duration (greater than or equal to3 months) these differences were no longer detectable between both patient groups. Conclusions Diabetic patients with TCOs have similarly developed collaterals as nondiabetic patients. However, in TCOs <3 months duration the acute recruitment of collaterals in case of reocclusion is impaired. This could explain some of the higher complication rate and mortality after coronary interventions in diabetic patients. (C) 2003 The European Society of Cardiology. Published by Elsevier Science Ltd. All rights reserved.