Discordant Hemodynamic and Fibrinolytic Adaptations Following a 6-Week Cardiac Rehabilitation Program

Haemostasis and fibrinolysis after regular high-intensity interval training in patients with coronary artery disease: a randomised controlled trial

IntroductionPatients with coronary artery disease (CAD) have prothrombotic changes compared with healthy individuals. Regular exercise reduces cardiovascular mortality in patients with stable CAD. However, the underlying mechanism for the beneficial effect is unknown. We investigated whether regular exercise would inhibit platelet aggregation and thrombin generation and increase fibrinolysis in patients with CAD.

MATERIALS AND METHODS

Patients with CAD were randomised 1:1 to a supervised high-intensity exercise training programme or standard care for 12 weeks. Blood samples were obtained at baseline and after 6 and 12 weeks. Platelet aggregation was evaluated with the Multiplate Analyser, thrombin generation using the calibrated automated thrombogram and fibrinolysis employing a clot lysis assay.

RESULTS

A total of 169 stable patients with CAD were randomised, and 142 patients (67±9 years, 83% males) completed the study; 64 in the exercise group and 78 in the standard care group. All but one patients received single antiplatelet therapy. From baseline to 12 weeks postintervention (Δ), no significant between-group differences were found in adenosine diphosphate-induced platelet aggregation (Δ-15 aggregation units (AU), AU×min, 95% CI -70 to 40 in the exercise group and Δ-26 AU×min, 95% CI -77 to 26 in the standard care group, p=0.44); endogenous thrombin potential (medians: Δ-5%, 95% CI -12 to 3 in the exercise group and Δ-6%, 95% CI -13 to 1 in the standard care group, p=0.26); nor in 50% clot lysis time (medians: Δ-9%, 95% CI -23 to 7 in the exercise group and Δ-17%, 95% CI -29 to -3 in the standard care group, p=0.60).

CONCLUSIONS

Twelve weeks of high-intensity whole-body endurance exercise did not affect platelet aggregation, thrombin generation or fibrinolysis in patients with stable CAD.

TRIAL REGISTRATION NUMBER

NCT04268992.

Hemostatic Adaptations to High Intensity Interval Training in Healthy Adult Men

Regular exercise is theorized to reduce cardiovascular risk by attenuating coagulation and augmenting fibrinolysis. However, these adaptations have not been consistently observed during traditional exercise programs. The purpose of this study was to examine hemostatic adaptations in healthy men following four (4W) and eight (8W) weeks of high intensity interval training. Twenty-one men (age=25±1 y; body mass index=26.5±6.4 kg/m²) completed eight weeks, three days/week of high intensity interval training on a cycle ergometer. Activated partial thromboplastin time, prothrombin time, and plasma concentrations of thrombin-antithrombin III, fibrinogen, tissue plasminogen activator, and plasminogen activator inhibitor-1 were assessed at baseline (BL), 4W, and 8W. Repeated measures ANOVA were used to determine potential effects of training. There were no significant changes observed for activated partial thromboplastin time (BL=43.3±5.5, 4W=43.2±5.1, 8W=44.2±6.4 s); prothrombin time (BL=13.2±0.9, 4W=13.0±0.6, 8W=13.1±0.8 s); thrombin-antithrombin III (BL=6.0±2.3, 4W=5.8±2.3, 8W=5.6±3.1 ng/mL); tissue plasminogen activator (BL=9.7±3.3, 4W=9.4±3.2, 8W=8.7±2.8 ng/mL); and plasminogen activator inhibitor-1 (BL=19.0±17.5, 4W=19.3±17.0, 8W=18.9±18.9 ng/mL) (all p>0.05). Fibrinogen was significantly lower at 4W (238.6±70.3 mg/dL) compared to BL (285.0±82.1 mg/dL; p<0.05) and 8W (285.3±83.2 mg/dL; p<0.05). These findings indicate that eight weeks of high intensity interval training does not influence coagulation potential and/or stimulate fibrinolysis.

Physical activity habits of cardiac patients participating in an early outpatient rehabilitation program

PURPOSE

The primary purpose of the study was to assess whether physical activity (PA) habits change following 4 to 6 weeks of an early outpatient cardiac rehabilitation (CR) program. A secondary purpose was to determine whether the PA habits differ on days attending CR versus not attending CR.

METHODS

Fourteen men and 8 women completed the study (age = 65.6 +/- 13.2 years, body mass index = 29.1 +/- 4.6 kg/m). Subjects wore an accelerometer during the entry and exit weeks of CR participation. Steps per day, activity counts per observation minute, percentage time spent inactive, light-intensity PA minutes per day, and moderate-intensity PA minutes per day were compared both at entry and exit from CR and on days attending CR and not attending CR.

RESULTS

From entry to exit of the early outpatient CR, patients increased total PA behavior (194.4 +/- 2 to 217.8 +/- 15.3 activity counts per observation minute) and time spent in moderate-intensity PA (13.9 +/- 2.3 to 18.7 +/- 2.5 min/d). Patients were more active, both in total activity (224.0 +/- 15.6 activity counts per observation minute vs 188.2 +/- 14.5 activity counts per observation minute) and in moderate intensity (19.7 +/- 3.3 min/d vs 12.8 +/- 2.0 min/d), on days they attended CR than on days they did not attend CR.

CONCLUSIONS

These data support the value of early outpatient CR programs for increasing patient PA levels, particularly moderate-intensity PA on days during which patients attended CR. Because PA targets for coronary risk reduction are not being achieved when patients exit CR, referral to a maintenance CR program and support for performing PA on days they do not attend CR become essential.