Angiotensin-Converting Enzyme Genotype is Not Associated With Exercise Capacity or the Training Effect of Cardiac Rehabilitation in Patients After Acute Myocardial Infarction

Apolipoprotein B and angiotensin-converting enzyme polymorphisms and aerobic interval training: randomized controlled trial in coronary artery disease patients

Physical training has been strongly recommended as a non-pharmacological treatment for coronary artery disease (CAD). Genetic polymorphisms have been studied to understand the biological variability in response to exercise among individuals. This study aimed to verify the possible influence of apolipoprotein B (ApoB: rs1042031 and rs693) and angiotensin-converting enzyme (ACE-ID: rs1799752) genotypes on the lipid profile and functional aerobic capacity, respectively, after an aerobic interval training (AIT) program in patients with CAD and/or cardiovascular risk factors. Sixty-six men were randomized and assigned to trained group (n=32) or control group (n=34). Cardiopulmonary exercise test was performed to determine the ventilatory anaerobic threshold (VAT) from cardiorespiratory variables. The AIT program, at an intensity equivalent to %VAT (70-110%), was conducted three times a week for 16 weeks. ApoB gene polymorphisms (-12669C>T (rs1042031) and -7673G>A (rs693)) were identified by real-time polymerase chain reaction (PCR). I/D polymorphism in the ACE gene (rs1799752) was identified through PCR and fragment size analysis. After 16 weeks, low-density lipoprotein (LDL) levels increased in the trained and control groups with the GA+AA genotype (-7673G>A) of the ApoB gene. Trained groups with ACE-II and ACE-ID genotypes presented an increase in oxygen consumption (VO2VAT) and power output after the AIT program. The presence of the ACE I-allele was associated with increased aerobic functional capacity after the AIT program. Increased LDL levels were observed over time in patients with the -7673G>A polymorphism of the ApoB gene. Trial Registration Information: ClinicalTrials.gov: NCT02313831.

ACE (I/D) polymorphism and response to treatment in coronary artery disease: a comprehensive database and meta-analysis involving study quality evaluation

BACKGROUND

The role of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in modifying the response to treatment modalities in coronary artery disease is controversial.

METHODS

PubMed was searched and a database of 58 studies with detailed information regarding ACE I/D polymorphism and response to treatment in coronary artery disease was created. Eligible studies were synthesized using meta-analysis methods, including cumulative meta-analysis. Heterogeneity and study quality issues were explored.

RESULTS

Forty studies involved invasive treatments (coronary angioplasty or coronary artery by-pass grafting) and 18 used conservative treatment options (including anti-hypertensive drugs, lipid lowering therapy and cardiac rehabilitation procedures). Clinical outcomes were investigated by 11 studies, while 47 studies focused on surrogate endpoints. The most studied outcome was the restenosis following coronary angioplasty (34 studies). Heterogeneity among studies (p < 0.01) was revealed and the risk of restenosis following balloon angioplasty was significant under an additive model: the random effects odds ratio was 1.42 (95% confidence interval:1.07-1.91). Cumulative meta-analysis showed a trend of association as information accumulates. The results were affected by population origin and study quality criteria. The meta-analyses for the risk of restenosis following stent angioplasty or after angioplasty and treatment with angiotensin-converting enzyme inhibitors produced non-significant results. The allele contrast random effects odds ratios with the 95% confidence intervals were 1.04(0.92-1.16) and 1.10(0.81-1.48), respectively. Regarding the effect of ACE I/D polymorphism on the response to treatment for the rest outcomes (coronary events, endothelial dysfunction, left ventricular remodeling, progression/regression of atherosclerosis), individual studies showed significance; however, results were discrepant and inconsistent.

CONCLUSION

In view of available evidence, genetic testing of ACE I/D polymorphism prior to clinical decision making is not currently justified. The relation between ACE genetic variation and response to treatment in CAD remains an unresolved issue. The results of long-term and properly designed prospective studies hold the promise for pharmacogenetically tailored therapy in CAD.

Heritability, Linkage, and Genetic Associations of Exercise Treadmill Test Responses

Background— The blood pressure (BP) and heart rate responses to exercise treadmill testing predict incidence of cardiovascular disease, but the genetic determinants of hemodynamic and chronotropic responses to exercise are largely unknown.

Methods and Results— We assessed systolic BP, diastolic BP, and heart rate during the second stage of the Bruce protocol and at the third minute of recovery in 2982 Framingham Offspring participants (mean age 43 years; 53% women). With use of residuals from multivariable models adjusted for clinical correlates of exercise treadmill testing responses, we estimated the heritability (variance-components methods), genetic linkage (multipoint quantitative trait analyses), and association with 235 single-nucleotide polymorphisms in 14 candidate genes selected a priori from neurohormonal pathways for their potential role in exercise treadmill testing responses. Heritability estimates for heart rate during exercise and during recovery were 0.32 and 0.34, respectively. Heritability estimates for BP variables during exercise were 0.25 and 0.26 (systolic and diastolic BP) and during recovery, 0.16 and 0.13 (systolic and diastolic BP), respectively. Suggestive linkage was found for systolic BP during recovery from exercise (locus 1q43−44, log-of-the-odds score 2.59) and diastolic BP during recovery from exercise (locus 4p15.3, log-of-the-odds score 2.37). Among 235 single-nucleotide polymorphisms tested for association with exercise treadmill testing responses, the minimum nominal probability value was 0.003, which was nonsignificant after adjustment for multiple testing.

Conclusions— Hemodynamic and chronotropic responses to exercise are heritable and demonstrate suggestive linkage to select loci. Genetic mapping with newer approaches such as genome-wide association may yield novel insights into the physiological responses to exercise.

Poor implementation of cardiac rehabilitation despite broad dissemination of coronary interventions for acute myocardial infarction in Japan: a nationwide survey

BACKGROUND

The implementation of cardiac rehabilitation (CR) after acute myocardial infarction (AMI) has not been fully investigated in Japan, so a nationwide survey of hospitals was conducted.

METHODS AND RESULTS

Questionnaires were sent in 2004 to a total of 1,875 hospitals in Japan, including all the 859 Japanese Circulation Society (JCS)-authorized cardiology-training hospitals (THs), 311 JCS-associated hospitals (AH), and 705 randomly sampled non-THs (NTHs). The response rate was 59% (1,106/1,875). The percentages of hospitals treating hospitalized AMI patients were 97% in 526 TH, 85% in 194 AH, and 20% in 339 NTH. Although the rates of implementation of emergency percutaneous coronary intervention were very high (92%, 56%, and 4%, respectively), the rates of implementation of recovery phase CR were low (20%, 8%, and 2%, respectively). In addition, patient education programs (23%, 13% and 2%) and formulated exercise prescriptions based on exercise testing (16%, 7% and 1%) were poorly implemented. More importantly, only 9%, 2% and 0% of these hospitals had outpatient CR programs. From these data, the nationwide participation rate in outpatient CR after AMI in Japan was estimated to be only 3.8-7.6%.

CONCLUSION

This first nationwide survey demonstrated that, in contrast to the broad dissemination of acute phase invasive treatment for AMI, the implementation of recovery phase CR, especially outpatient CR, is extremely poor in Japan. In addition, patient education programs and exercise prescription based on exercise testing are only poorly implemented.

Are Cardiac Events During Exercise Therapy for Heart Failure Predictable From the Baseline Variables?

BACKGROUND

Exercise training (ET) is an emerging therapy for chronic heart failure, but the baseline patient characteristics for predicting cardiac events (CEs) during the course of ET remain unknown.

METHODS AND RESULTS

Of the 111 stable heart failure patients who participated in a 3-month ET program, 6 withdrew from the program for cardiac reasons and 9 had transient interruptions in the program because of CEs. The baseline clinical characteristics of these 15 patients (CE group) and the remaining 96 patients (No-CE group) were compared. Compared with the No-CE group, the CE group had a significantly higher prevalence of pacemaker/implantable cardioverter-defibrillators, larger left ventricular end-diastolic diameter (LVEDDs), lower peak oxygen uptake, greater ventilation drive, and higher plasma brain natriuretic peptide concentration at baseline. Multivariate logistic regression analysis showed that a larger LVEDD was a significant predictor of the occurrence of a transient interruption to or permanent withdrawal from the ET program because of CEs. Receiver operating characteristic curve analysis demonstrated that an LVEDD > or = 65 mm had a sensitivity of 93% and specificity of 48% in predicting CEs.

CONCLUSIONS

Patients with a large LVEDD (> or = 65 mm) at baseline should be monitored carefully during the course of an ET program.