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Background

Endothelial dysfunction is relevant in patients with coronary artery disease (CAD), and the presence of severe endothelial dysfunction is associated with a less favorable prognosis.

Exercise training (ET) is now generally accepted as a nonpharmacological intervention to improve endothelial function for patients with CAD.

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Rationale

Studies on the effect of ET on endothelial function in patients with CAD focused mainly on aerobic training.

Optimal intensity, volume, and modalities of exercise training are still unclear.

The American Heart Association (AHA) focused on the beneficial impact of resistance training in patients with CAD, but the effects of resistance training on vascular function remain unclear.

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Purpose and Hypothesis

No study has compared the impact of resistance and aerobic training on endothelial function.

To evaluate the effect of different types of ET on endothelial function in patients after a first recent acute myocardial infarction.

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Methodology- Participants

n= 209 (155 Male; 54 Female)

Inclusion: The ability to exercise, absence of previous cardiovascular events, absence of diabetes and/or hypertension, nonsmoker or ex-smoker for >10 years, left ventricular ejection fraction >45%, and no echocardiographic evidence of ventricular hypertrophy

Exclusion: Patients taking calcium antagonists; patients with hemodynamically significant valvular heart disease; those who had had cardiopulmonary bypass surgery; and patients with chronic lung disease, systemic and/or hematologic illnesses, and hepatic or renal insufficiency (creatinine >2.5 mg/dL).

All patients underwent coronary angiography immediately after admission to the hospital

76% underwent coronary angioplasty with stent positioning during or immediately after the acute phase of myocardial infarction.

All patients were being treated with Beta-blockers, angiotensin-converting enzyme inhibitors, statins, and aspirin at the time of the study.

CONSISTENT SAMPLE AT LOW CARDIAC RISK

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Methodology – Dependent Variables

Baseline evaluation (blood panel, ekg, x-ray, cardiopulmonary exercise test).

Endothelia function assessed via brachial artery reactivity using 2-dimensional ultrasonography (Flow-Mediated Dilation [FMD]).

Endothelium-independent vasodilatation assessed by images after inducing sublingual nitroglycerin.

Blood draw to determine the plasma levels of von Willebrand factor (vWF).

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Methodology – Independent Variables - ET

Patients randomized into 4 groups:

G1- aerobic training (n=58), moderate aerobic training 4 times a week for 4 weeks (40 min; cycling)

G2 - resistance training (n=57), 4 times a week for 4 weeks (trained at 60% of pretraining maximum voluntary contraction)

G3 - aerobic & resistance training combined (n=57), alternated controlled resistance and controlled aerobic training sessions (2 sessions of resistance training and 2 sessions of aerobic training a week)

G4 - no training (control group, n=56)

INTENSITY AND DURATION PROGRESSIVELY INCREASED IN ET GROUPS

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Methodology - Detraining

Patients stopped structured sessions of physical activity.

Patients completed home daily physical activity registers about their total physical activity during both the training and detraining phases.

Duration: 1 month

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Methodology – Follow up

All tests repeated and compared to baseline measurements

n= 209

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Statistical Analysis

Data presented as mean +/- SD

Baseline values were compared by use of 1-way ANOVA and Tukey posthoc multiple comparison test.

Magnitude of brachial artery reactivity difference among the ET groups and control was compared by repeated-measures ANOVA and Tukey posthoc test.

Relationship between FMD and vWF level changes after training was compared by linear regression analysis.

A value of P<0.05 was considered statistically significant.

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Results

Peak V ̇ O increased significantly

Significant improvement in brachial artery endothelium-dependent relaxation

FMD increased

vWF decreased by 16%

Changes in FMD were correlated with changes in vWF levels

After 1 month of detraining, work tolerance was reduced by 16 +/-2.3%. Brachial artery baseline diameter remained essentially the same, but FMD was significantly lower after detraining than at the end of the training period.

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Results

Figure 1. Percent change in FMD during the brachial reactivity study, ET Groups vs control group. FMD was significantly increased after 1 month of physical training.

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Results

Table 4. Brachial Reactivity Results at Baseline and Follow-Up

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Results

Figure 2. Relation between percent change in vWF and percent change in FMD after training.

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Results

Table 5. vWF Results

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Conclusion

In patients with recent acute myocardial infarction, ET was associated with improved endothelial function independently of the type of training, but this effect disappeared after 1 month of detraining

We should encourage variety in the prescription of exercise to promote better adherence to long-term physical training.

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References

Vona, M., Codeluppi, G. M., Iannino, T., Ferrari, E., Bogousslavsky, J., & von Segesser, L. K. (2009). Effects of different types of exercise training followed by detraining on endothelium-dependent dilation in patients with recent myocardial infarction. Circulation, 119(12), 1601–1608. https://doi.org/10.1161/circulationaha.108.821736