ESC Congress 2026 Abstract · Oct 26, 2026

Twelve months of exercise training did not alter coronary flow reserve or microvascular resistance reserve in patients with old myocardial infarction

By Saeland C, Hjellbakk HK, Ogne C et al.

Background: Coronary Flow Reserve CFR defined as Qmax/Qrest represents the reserve capacity of the coronary circulation. Microvascular Resistance Reserve (MRR) defined as (Qmax/Qrest)×(Pa,rest/Pd,hyper) has been shown to be the most specific index of microvascular dysfunction and specific prognostic effect of MRR related to both survival and adverse outcomes has been demonstrated. Little is known about these parameters in patients with previous myocardial infarction. Furthermore, there is few data on the relationship between these parameters and vessel-stiffness, and flow mediated vasodilatation (FMD). Finally, there are no reports on alterations of these parameters after a 12-month exercise training program. Purpose: To assess coronary microvascular function using CFR and MRR calculated with measures obtained invasively with continuous thermodilution in patients with an old myocardial infarction. To explore the relationship between these parameters and FMD and Vessel Stiffness. To assess changes in CFR and MRR after 12 months of exercise training and correlations between changes in these parameters. Methods: Twenty-one patients with previous myocardial infarction during 2013-2018 were included. Continuous saline thermodilution measurements were obtained in the not infarction related artery at baseline and after 12 months, at rest and during hyperemia from the Coroventis software (CFR, FFR and MRR). Endothelial function and vessel-stiffness VO2max was measured before and after the intervention period. The patients were randomized to structured physical activity during the test period with at least 100 minutes of weekly physical activity exercise training (ET) or advised to follow guidelines recommended ET. The study was approved by the Regional Committee for Medical and Health Research Ethics (REK) Health MIDT. Results: At baseline mean CFR 3,5852 (1,77-5,43) and mean MRR 4,3144 (2,28-6,76) were averaged within normal limits. Six patients had CFR < 3,0. When comparing values from intervention group with the control group we found no significant differences between the groups. The two groups were therefore merged. For the whole group there were no significant changes in CFR or MRR between baseline and 12 months. FMD increased (Table 1). We found no significant correlations between changes in CFR and MMR with physiological parameters for FMD or CAVI. After 12 months changes in CFR were strongly correlated with changes in MRR (figure1). Conclusions: CFR and MMR calculated with measures obtained invasively with continuous thermodilution in patients with an old myocardial infarction were within normal limits. There were no changes in CFR or MRR after 12 months of exercise training. Changes in CFR were strongly correlated with changes in MRR.

doi.org/10.1093/eurheartj/ehag785.1576 Open access Interventions