Improved Endothelial Function and Reversal of Myocardial Perfusion Defects after Aerobic Physical Training in a Patient with Microvascular Myocardial Ischemia

Use of a single-item exercise questionnaire predicts prognostic risk among patients undergoing stress PET-MPI

BACKGROUND

Exercise activity reduces mortality and favorably influences mediators of risk, including myocardial flow reserve (MFR) and chronotropic responsiveness. Comprehensive research regarding the relationship between exercise activity, MFR, and chronotropic response to pharmacological stress, as assessed by heart rate response (HRR) among patients undergoing PET myocardial perfusion imaging (MPI) has not been performed. Thus, we aimed to evaluate the relationship between exercise activity as assessed by a practical single-item questionnaire, MFR and HRR, and longitudinal clinical risk.

METHODS

We studied outpatients who underwent pharmacological stress rubidium-82. PET-MPI and answered a self-reported one-item exercise activity questionnaire (0-10 scale) at the time of PET-MPI. HRR was calculated by the following equation: (stress HR-rest HR)/rest HR∗100 (%). The primary outcome was death or myocardial infarction.

RESULTS

Of 1686 patients, 221 (13%) patients had hard events during our mean follow up of 3.8 years. Patients were divided into four groups: no/minimal exercise (n = 551), low exercise (n = 468), moderate exercise (n = 485), and high exercise (n = 182) based on the questionnaire. MFR and HRR increased with exercise activity in a stepwise manner. By Cox analysis adjusted for clinical and PET-MPI variables including MFR and HRR, exercise activity was independently associated with hard events (HR [95%CI] per activity scale, .95 [.91-.99]; P = .028).

CONCLUSIONS

Patients with higher exercise activity assessed by a practical single-item questionnaire had higher MFR and HRR. Exercise activity was an independent predictor of hard events in patients undergoing PET-MPI. Because of its ease of use, this single-item questionnaire should be applied among patients undergoing stress MPI.

Cardiac Rehabilitation and Exercise Prescription in Symptomatic Patients with Non-Obstructive Coronary Artery Disease-a Systematic Review

Purpose of review

Non-obstructive coronary artery disease (NOCAD) on coronary angiography is a common finding in patients with stable angina. Angina in NOCAD patients is thought to be caused by endothelial dysfunction of the epicardial coronary arteries and/or the microvasculature. Treatment is empiric, and 30% of patients remain symptomatic in spite of therapy. It is well known that physical exercise can improve endothelial function. The goal of this review was to assess the current literature on effects of physical exercise in NOCAD patients with angina. Therefore, a literature search was conducted to March 13, 2018 using the following search terms: syndrome X, microvascular angina, non-obstructive coronary artery disease and exercise training, cardiac rehabilitation, endothelial function. All original publications were included which examined the effect of a cardiac rehabilitation (CR) program or exercise training (ET) on patients with angina and NOCAD.

Recent findings

Eight studies, of which four were randomized controlled studies, examined 218 participants, 162 in an intervention and 56 in control groups. Most patients were women (97.7%). Exercise programs varied from 8 weeks to 4 months at moderate intensity and some included relaxation therapy. The studies examined the effect of CR on exercise capacity, quality of life (QoL), and perfusion defects. CR increased exercise capacity, oxygen uptake, symptom severity, and QoL. Myocardial perfusion improved.

Summary

CR appears to be beneficial in symptomatic patients with NOCAD, improving exercise capacity and QoL and reducing severity of symptoms and myocardial perfusion defects. Data is limited to a small number of predominantly female patients. Further larger trials are warranted to determine the optimal rehabilitation protocols and define its long-term benefits.

Physical training improves myocardial perfusion but not left ventricular function response to exercise in patients with microvascular angina

BACKGROUND

Patients with primary microvascular angina (PMA) commonly exhibit abnormal left ventricular function (LVF) during exercise, potentially owing to myocardial ischemia. Herein, we investigated in PMA patients the effect of the reduction of myocardial perfusion disorders, by using aerobic physical training, upon LVF response to exercise.

METHODS

Overall, 15 patients (mean age, 53.7±8.9 years) with PMA and 15 healthy controls (mean age, 51.0±9.4 years) were studied. All subjects were subjected to baseline resting and exercise ventriculography, myocardial perfusion scintigraphy (MPS), and cardiopulmonary testing. PMA group members then participated in a 4-month physical training program and were reevaluated via the same methods applied at baseline.

RESULTS

Baseline left ventricular ejection fraction (LVEF) determinations by ventriculography were similar for both groups (PMA, 67.7±10.2%; controls, 66.5±5.4%; P=0.67). However, a significant rise in LVEF seen in control subjects during exercise (75.3±6.2%; P=0.0001) did not materialize during peak exercise in patients with PMA (67.7±10.2%; P=0.47). Of the 12 patients in the PMA group who completed the training program, 10 showed a significant reduction in reversible perfusion defects during MPS. Nevertheless, LVEF at rest (63.5±8.7%) and at peak exercise (67.3±15.9%) did not differ significantly (P=0.30) in this subset.

CONCLUSIONS

In patients with PMA, reduced left ventricular inotropic reserve observed during exercise did not normalize after improving myocardial perfusion through aerobic physical training.

Calcitonin gene-related peptide in aerobic exercise induces collateral circulation development in rat ischemia myocardium

PURPOSE

Aerobic exercise may offer favorable effects for coronary perfusion in the myocardial ischemia area, although the underlying molecular mechanisms remain unclear. This study was designed to investigate the effect of aerobic exercise on the collateral circulation in the ischemia myocardium and to evaluate calcitonin gene-related peptide (CGRP) changes during this process.

METHODS AND RESULTS

Wistar rats were randomly divided into 3 groups of 7 rats each: a sham operated group (Sham), a myocardial ischemia-only group (MI) and a MI plus aerobic exercise group (MI+AE). The rat myocardial ischemia model was established by injecting isoprenaline (2mg/kg, i.p.). The aerobic exercise training consisted of swimming (40min/d, 5d/wk) for 4 weeks. At the end-points, after echocardiographic analysis was performed, blood and ischemia myocardium samples were collected and analyzed by ELISA to quantify the CGRP protein. The dorsal root ganglia were isolated and analyzed by reverse transcription polymerase chain reaction (RT-PCR) to examine the CGRP mRNA expression, and ischemia myocardium capillary density was evaluated by immunohistochemistry. Our data showed that the capillary density in the left ventricle and heart function were significantly decreased with decreased CGRP production in the MI rats, which were reversed by aerobic exercise in the MI+AE rats.

CONCLUSION

These results indicate that aerobic exercise may alleviate myocardial ischemia through collateral circulation development with increased CGRP production. CGRP may play an important role in developing the collateral circulation.

Microvascular angina: an update on diagnosis and treatment

ABSTRACT 

Many patients with chest pain who are relieved to learn that they have no obstructive stenoses at diagnostic angiography are misclassified as having noncardiac chest pain. Only recently have we developed the conceptual framework and diagnostic tools to understand that ischemic heart disease is not exclusively caused by obstructive coronary artery disease, but often has its origin in the microcirculation. This article will focus on the diagnosis and treatment of microvascular angina as a cause of myocardial ischemia in patients with abnormal but ‘normal appearing’ coronary arteries.

Cardiac rehabilitation for women across the lifespan

Cardiac rehabilitation improves function and compliance and also reduces morbidity and mortality in female and male cardiovascular disease patients but remains significantly underutilized. At every age, and especially in their senior years, female cardiovascular disease patients are under-referred relative to men. Lack of standardized referral processes, misconceptions by physicians and patients, and idiosyncrasies of female pathophysiology contribute to this pattern. Moreover, confounding factors of age, socioeconomic status, and sex-specific roles and responsibilities exacerbate the problem. This review summarizes barriers to cardiac rehabilitation for female cardiac patients, and highlights opportunities for increased participation and benefit.