PCI Alternative Using Sustained Exercise

Overview

Cardiovascular disease remains the leading cause of morbidity and mortality in the U.S. and is a major cause of disability in Veterans. Most of these deaths are due to coronary artery disease (CAD). The most common treatment for CAD is revascularization, an invasive procedure which usually involves placing a stent inside an artery that is diseased. However, exercise training is often overlooked because clinicians tend to focus on repairing the coronary circulation and the potential need for revascularization. Studies have shown that exercise training can be effective for patients with CAD and that it saves costs. In this study, invasive revascularization will be compared to a structured program of exercise training over one year. Comparisons will be made between groups for symptoms, coronary artery size and function using PET/CTA, and health care cost utilization.

Despite advances in treatment options for cardiovascular disease (CVD), this condition remains the leading cause of morbidity and mortality in the U.S. and is a major cause of disability in Veterans. Percutaneous coronary intervention (PCI) is the treatment most often used in patients with various manifestations of coronary artery disease (CAD). While it is commonly assumed that PCI also reduces mortality, randomized trials have shown that PCI has no effect on mortality except in patients being treated for acute myocardial infarction. Over the last decade, the use of PCI has increased exponentially; between 1996 and 2007, the number of PCIs performed in the US has increased more than 4-fold, from approximately 300,000 to more than 1.3 million yearly. During this time, PCI has accounted for 10% of the overall increase in Medicare expenditures. In light of the extraordinary increase in the use of this technology in recent years, questions have been raised regarding the cost-effectiveness of PCI, the extent to which PCI is overused, and whether selected patients may benefit from optimal medical therapy in lieu of PCI. Cost analyses have suggested that the current rate of increase in PCI with DES is unsustainable for the U.S. healthcare system. Given the costs associated with PCI, there have been recent efforts to compare outcomes and effectiveness of PCI against non-invasive therapy. There is a need to evaluate more judicious use of PCI, and to consider less costly interventions for at least some of the \>1.3 million patients in the U.S. who undergo this procedure. Lifestyle intervention, including exercise training, is one option that has been shown to result in reduced symptoms, better exercise tolerance, improved quality of life and lower mortality. A growing body of data has demonstrated that exercise intervention improves coronary anatomy and lessens ischemia through enhanced endothelial function. While a significant proportion of health care expenditures are devoted to PCI and other invasive interventions for CVD, few health care resources are directed toward primary or secondary prevention. Recent studies have demonstrated that programs of cardiac rehabilitation, with and without implementation of intensive risk reduction, are cost effective. In part because of the financial interests associated with PCI, exercise and lifestyle intervention is rarely considered as a clinical treatment option in PCI candidates. A gap exists between the standard clinical treatment for CAD and the potential for non-invasive, less expensive and potentially more effective treatments for these patients. Previous efforts to quantify the effects of exercise and lifestyle intervention on coronary artery perfusion and anatomy have been limited to standard angiography. In recent years, improved technologies for imaging coronary perfusion and anatomy have been developed, which could provide important insights into the effects of exercise training on the heart. These include the combination of positron emission tomography and ultra-fast computed tomography angiography (CTA), commonly termed PET/CTA. PET provides information on the functional significance of anatomic stenoses by measuring myocardial blood flow and myocardial perfusion reserve. PET can also be used to evaluate coronary endothelial function by measurements of changes in myocardial blood flow in response to physical stimuli (i.e., cold pressor testing). The combination of CTA with PET also allows for improved attenuation correction. CTA, on the other hand, can noninvasively image the coronary arteries to determine the severity of stenosis and the amount of calcified and noncalcified plaque burden. The investigators have termed the current proposal "PCI Alternative Using Sustained Exercise" (PAUSE) to reflect the potential for exercise training and lifestyle intervention as alternative therapies in selected PCI candidates. Primary aim: To determine whether subjects with lesions amenable to PCI randomized to a 1 year exercise program and lifestyle intervention have greater improvement in coronary perfusion and function than those randomized to PCI. Secondary analyses: The investigators will compare exercise test responses, health care costs, quality of life, and clinical outcomes between groups.