ECSS Paris 2023: OP-MH37
INTRODUCTION: Cardiac rehabilitation (CR) represents a comprehensive intervention to address reduced exercise capacity and early vascular aging (VA) in coronary artery disease (CAD) patients. Intermittent hypoxic-hyperoxic training (IHHT) may improve mitochondrial function and promote vascular regeneration through adaptive cellular mechanisms. The aim of this randomized controlled trial was to investigate the effects of IHHT on exercise capacity and markers of VA in CAD patients during CR. METHODS: 36 CAD patients following myocardial infarction and/or percutaneous coronary intervention referred to 3-4 weeks of inpatient CR were randomized into an IHHT (N=18; 31% female; 53.9±9.2 years) or control group (CG, N=18; 37% female; 58.4±8.0 years). Full-clinical assessment included cardiopulmonary exercise testing, functional tests (6-MWT and Chair Rise Test) and pulse wave analysis (PWA) as well as disease perception questionnaires at admission and before discharge. In addition to standard CR, IHHT patients were prescribed three weekly sessions (30-40 min/session) consisting of six to eight individually adjusted cycles alternating between hypoxic (10-12% O2, 3-5 min) and hyperoxic breathing (30-35% O2). CG patients received standard care with additional relaxation and breathing exercises (3 sessions/week, 30 min). RESULTS: Patients completed 24.8±3.6 days of CR, with IHHT patients receiving 6.9±1.2 sessions corresponding to 26±6 min of hypoxic breathing per patient. No adverse events were reported. Improvement in submaximal and peak exercise capacity (workload and oxygen uptake) and functional tests were not different between IHHT and CG (p>0.05). However, improvement in peak oxygen uptake (VO2peak) was larger in IHHT (+1.9±1.7 ml/min/kg) compared to CG (+0.8±2.3 ml/min/kg) but missed statistical significance (p=0.098). In addition, IHHT demonstrated significantly greater improvements in respiratory minute volume (IHHT, +9.3±10.6 l/min; CG, +2.4±9.8 l/min; p=0.049), with changes correlating with those observed for VO2peak (p<0.001; r=0.83). PWA revealed significant differences in Pulse Pressure Amplification (PPA), reducing the cardiac load on the heart (decreased PPA is a key indicator of VA) (IHHT, +0.05±0.11; CG, -0.06±0.06; p=0.002). Also, Total Vascular Resistance (IHHT, -0.11±0.22 s/mmHg/ml; CG, +0.06±0.21 s/mmHg/ml; p=0.031), Augmentation Pressure (IHHT, -5.27±8.88 mmHg; CG: +1.38±3.86 mmHg; p=0.038) and Augmentation Index (IHHT, -9.6±14.4%; CG, +4.1±11.6%; p=0.004), were improved in IHHT. CONCLUSION: IHHT demonstrated beneficial effects on ventilatory efficiency at peak exercise and markers of VA, particularly pulse pressure amplification and arterial stiffness indices. A tendency for greater improvement of VO2peak in the IHHT group was also observed. These findings suggest that IHHT may serve as a valuable adjunct to CR by targeting vascular function and hemodynamic parameters in CAD patients, potentially improving mitochondrial function.
Read CV René GarbschECSS Paris 2023: OP-MH37
INTRODUCTION: Cardiovascular risk factors are associated with impaired peripheral endothelial and microvascular function, contributing to increased cardiovascular risk. Although exercise training is recommended to improve vascular health, evidence suggests that vascular adaptations to exercise are attenuated or highly variable in older adults living with multiple cardiovascular risk factors. Moreover, vascular adaptations to longer-term exercise training in this population remain limited. This study tested the hypothesis that a 46-week exercise training intervention improves peripheral endothelial function, microvascular function, and blood pressure in adults with living cardiovascular risk factors. METHODS: Nineteen sedentary adults were included (age: 70 ± 6 years; 11 females and 8 males). Among females, the most prevalent risk factors were physical inactivity (73%), obesity (46%), dyslipidemia (36%), and hypertension (36%). Among males, physical inactivity was present in all participants (100%), followed by obesity (63%) and dyslipidemia (63%). No participants were current smokers. Participants completed 46 weeks of supervised exercise training that included three 60-minute sessions per week of combined and progressive aerobic and resistance training. Peripheral endothelial function was assessed using brachial artery flow-mediated dilation (FMD), microvascular function was measured using laser Doppler flowmetry during post-occlusion reactive hyperemia, and blood pressure was measured at rest in triplicate. Pre-post comparisons were performed using paired t tests and mean differences (post minus pre) are presented with 95% confidence intervals. RESULTS: There was no change in brachial artery FMD expressed as a percentage (0.97% [−0.50, 1.20], p = 0.398) or in millimeters (−0.06 mm [−0.24, 0.12], p = 0.545). Cutaneous vascular conductance area under the curve (−0.25 units·mmHg⁻¹ [−0.82, 0.32], p=0.363) and peak conductance (−9.01mL·min⁻¹·mmHg⁻¹ [−38.98, 20.97], p=0.530) also did not differ from pre to post intervention. Finally, there were no differences in systolic (3.06 mmHg [−1.89, 8.01], p = 0.244) or diastolic (−2.12 mmHg [−5.60, 1.36], p = 0.248) blood pressure. CONCLUSION: In older adults living with multiple cardiovascular risk factors, a 46-week supervised exercise training intervention did not improve peripheral endothelial function, microvascular function, or blood pressure.
Read CV Katia OubouchouECSS Paris 2023: OP-MH37
INTRODUCTION: Patients with coronary artery disease (CAD) typically exhibit reduced peak oxygen uptake (V̇O2peak) which is associated with adverse clinical outcomes. Hemoglobin mass (Hbmass) and intravascular blood volumes are key determinants of V̇O2peak but have not yet been well characterized in this population. Therefore, we compared carbon monoxide rebreathing-derived Hbmass and intravascular blood volumes and V̇O2peak between patients with CAD and healthy controls (CON). METHODS: Forty-nine patients with CAD (12 females) and 27 healthy adults (13 females) completed a cardiopulmonary exercise test using a step-ramp-step protocol to determine V̇O2 and power output (PO) at the gas exchange threshold (GET), respiratory compensation point (RCP), and peak exercise (V̇O2peak and POpeak). On a separate day, Hbmass and intravascular volumes (total blood volume [BV], plasma volume [PV], and red blood cell volume [RBCV]) were assessed using a 5-min carbon monoxide rebreathing method. Group differences were analyzed using two-tailed independent samples t-tests with alpha set to 0.05. RESULTS: Height (172±10 vs 172±8 cm, p=0.960) and body mass (82±18 vs 78±12 kg, p=0.379) did not differ between CAD and CON groups, respectively. CAD were older than CON (64±11 vs 56±13 years; p=0.010, respectively). Compared to CON, CAD had lower V̇O2peak when expressed relative to body mass (23.7±6.3 vs 31.7±9.1 mL·kg-1·min-1; p<0.001) and as percentage of age-predicted maximum (102±23 vs 128±20 %; p<0.001), lower POpeak (146±53 vs 212±75 W; p<0.001), lower V̇O2 at RCP (19.8±4.7 vs 26.7±7.8 mL·kg-1·min-1; p<0.001) and at GET (15.4±4.0 vs 18.8±4.6 mL·kg-1·min-1; p=0.001) and lower PO at RCP (87±33 vs 133±47 W; p<0.001) and GET (64±26 vs 100±34 W; p<0.001). In contrast, no CAD vs CON differences were observed for Hbmass (9.9±1.9 vs 10.7±2.0 g·kg-1; p=0.077), BV (5.4±1.3 vs 5.8±1.1 L; p=0.285), PV (3.0±0.7 vs 3.2±0.6 L; p=0.291), nor RBCV (2.4±0.7 vs 2.6±0.6 L; p=0.346). In the CAD group, Hbmass (g·kg-1) was positively correlated with relative V̇O2peak (r=0.44, p=0.003). In CON, relative V̇O2peak correlated positively with Hbmass (g·kg-1; r=0.68, p<0.001), BV (L; r=0.61, p=0.001), PV (L; r=0.50, p=0.013), and RBCV (L; r=0.67, p<0.001). CONCLUSION: Despite reduced submaximal and maximal aerobic capacity in patients with CAD, Hbmass and intravascular volumes were comparable to healthy controls. These findings suggest that oxygen-carrying capacity does not contribute to the reduced V̇O2peak observed in CAD which may instead reflect limitations in peripheral or cardiovascular oxygen utilization.
Read CV Robin FaricierECSS Paris 2023: OP-MH37