Association of colchicine use with myocardial perfusion reserve after myocardial infarction: An ancillary analysis of the COLD-MI trial

BACKGROUND: Colchicine reduces sympathetic denervation after acute myocardial infarction (AMI), yet the COLD-MI trial found no change in myocardial perfusion scintigraphy (MPS). MPS-detected necrotic lesions were limited by early management, and MPS may therefore have lacked the sensitivity to capture subtle colchicine-induced variations in minimal necrosis during the immediate post-stenting period. Myocardial perfusion reserve (MPR), a quantitative indicator of global microvascular function, may overcome these limitations. This ancillary analysis of the COLD-MI trial evaluated whether colchicine improves MPR six months after AMI. METHODS: Forty-five post-AMI patients randomized to colchicine for 30 days or no colchicine underwent quantitative dynamic [99mTc]Tc-tetrofosmin SPECT and [123I]-mIBG imaging at 6 months. MPR was quantified using CZT-SPECT as the stress-to-rest uptake ratio. Secondary endpoints included MPS scoring (SRS, SSS, SDS) and sympathetic innervation assessed by normalized mean segmental activity. Analyses were blinded. RESULTS: Colchicine-treated patients showed significantly higher MPR in remote myocardium than controls (2.37 ± 0.61 vs. 1.92 ± 0.53; P = 0.01). Denervated myocardial surface area in remote regions was also lower with colchicine (43% [29-50] vs. 50% [38-64]; P = 0.04). In infarcted myocardium, MPR did not differ (1.79 ± 0.61 vs. 1.60 ± 0.63; P = 0.35). A non-significant trend toward better preserved innervation was observed (denervation: 46% [35-50] vs. 50% [45-69]; P = 0.09). SRS, SSS, and SDS were similar between groups. CONCLUSIONS: Colchicine significantly increases MPR in remote myocardium six months after AMI, consistent with reduced sympathetic denervation and supporting a microvascular benefit of colchicine post-AMI.