Impact of Ischemic Heart Disease and Cardiac Rehabilitation on Cerebrovascular Compliance

Study objective: To determine the influence of ischemic heart disease (IHD) and cardiac rehabilitation (CR) on cerebrovascular compliance index (Ci). Methods: Eleven (one female) patients with IHD (mean[SD]: 61[11] years, 29[4] kg/m²) underwent six months of CR, which consisted of ≥3 sessions/week of aerobic and resistance training (20-60 min each). Ten (three female) similarly aged controls (CON) were tested at baseline as a comparator group. Middle cerebral artery velocity (MCAv) and mean arterial pressure were monitored continuously using transcranial Doppler ultrasound and finger photoplethysmography, respectively, during a rapid sit-to-stand maneuver. A Windkessel model was used to estimate cerebrovascular Ci every 5 cardiac cycles for a duration of 30 s. Cerebrovascular resistance was calculated as the quotient of MAP and MCAv. Two-way ANOVAs were used to determine whether cerebrovascular variables differ during postural transitions between groups and after CR. Results: Baseline MCAv was higher in CON vs. IHD (P=0.014) and a time x group interaction was observed (P=0.045) where MCAv decreased more in CON after standing. Compared to the pre-condition, CR had no effect on MCAv (condition P=0.950) but a main effect of time indicated MCAv decreased from the seated position in both conditions (time P=0.013). Baseline cerebrovascular Ci was greater in IHD vs. CON (P=0.049) and the peak cerebrovascular Ci during the transition to standing was significantly higher in IHD compared to CON (interaction P=0.047). CR did not affect cerebrovascular compliance (P=0.452) and no time by condition interaction upon standing was present (P=0.174). Conclusion: Baseline cerebrovascular Ci is higher in IHD at baseline compared to CON, but six months of CR did not modify the transient increase in cerebrovascular Ci during sit-to-stand maneuvers.