Is new science driving practice improvements and better patient outcomes? Applications for cardiac rehabilitation

Abstract

Evidence from many clinical trials in recent years suggests that a large "treatment gap" exists between recommended therapies and the care that patients actually receive. This gap has been particularly apparent in the area of primary and secondary prevention of cardiovascular disease. In this article, three areas are discussed in which new scientific advances have not been adequately translated to clinical practice. These include: 1) the most appropriate measures to define the risks associated with obesity; 2) the underdiagnosis of obstructive sleep apnea and its relation to cardiovascular risk; and 3) the use and misuse of the exercise test and other functional status tools to predict health outcomes. Each is discussed in terms of how they should be quantified, their contribution to the estimation of cardiovascular disease risk, their response to interventions, and implications for cardiac rehabilitation. Clinical cardiac rehabilitation programs can benefit from routinely including these measures, both for their value in stratifying risk and for their importance in quantifying program efficacy. Physicians and allied health professionals should expand their routine medical evaluations and coronary risk factor profiling to include these measures.The growing worldwide burden of cardiovascular disease (CVD) mandates the development and implementation of effective population-based interventions for primary and secondary prevention. Unfortunately, the treatment of coronary artery disease has evolved from simple lifestyle modification in the mid-to-late 1960s, largely focused on early ambulation, exercise training, and a prudent diet, to an array of costly and palliative coronary revascularization procedures that are not without risk and, concomitantly, fail to aggressively address the underlying causes of disease.Aggressive risk-factor reduction and adjunctive pharmacotherapy, however, can stabilize and even reverse the otherwise inexorable progression of atherosclerotic coronary artery disease. Guidelines and recommendations for conventional coronary risk factors (e.g., hyper-cholesterolemia, hypertension, cigarette smoking, diabetes) are widely available, as are clinically relevant threshold values for their favourable PROCEEDINGS REPORT

Exercise-Based Cardiac Rehabilitation and Improvements in Cardiorespiratory Fitness: Implications Regarding Patient Benefit

“…After adjusting for age, each 1-MET increase in exit training level was associated with a 28% decrease in all-cause mortality. 13 Collectively, the aforementioned referenced studies (Table 1) and other recent reports 14 support the hypothesis that CRF provides a strong, graded inverse association with cardiovascular and all-cause mortality in patients with and without CHD, irrespective of sex, body mass index, major risk factors, heart failure, and other comorbid conditions. An exercise capacity of less than 5 METs correlates with a higher mortality group, whereas 9 to 10 METs or more generally identifies a cohort with an excellent long-term prognosis, regardless of the underlying extent of CHD.…”

Quantitating the Dose of Physical Activity in Secondary Prevention: Relation of Exercise Intensity to Survival

“…Vigorous exercise intensities are more effective than moderate intensities at increasing CRF, 25 especially for individuals with higher baseline CRF. 26 (median) reduction of 16% (range, 8%-35%) in mortality, 27 which compares favorably with the survival benefit conferred by low-dose aspirin, statins, b-blockers, and angiotensinconverting enzyme inhibitors after acute myocardial infarction. 28 Other possible mechanisms associated with vigorousintensity exercise training may include autonomic adaptations, specifically decreased sympathetic outflow and increased vagal tone, increased or maintained HR variability and endothelial function, decreased vascular stiffness, platelet adhesiveness, fibrinogen, and blood viscosity, increased diastolic filling time, augmenting coronary flow, and enhanced nitric oxide vasodilator function.…”

The effect of an expanded long-term periodization exercise training on physical fitness in patients with coronary artery disease: study protocol for a randomized controlled trial

“…Sample size was calculated (G-Power, Version 3.1.3) assuming a difference in VO 2 peak between groups of 3.5 mL/kg/min to be clinically relevant, where each 1 MET (3.5 mL/kg/min) increase in cardiorespiratory fitness is associated with an 8–35% reduction in overall mortality at 12 months [18–20]. Assuming a VO 2 peak standard deviation of 3.5 mL/kg/min, α = 0.05, 1-β = 0.80, and an expected dropout rate at 12 months of 37% [4], the calculations yielded a total minimum sample size of 50 participants (25 in each group).…”