Clinical Assessment: Cardio-Circulatory SystemSaturday, October 29, 2011
Today’s post is another excerpt from “Best Weight: A Practical Guide to Office-Based Weight Management“, recently published by the Canadian Obesity Network.
This guide is meant for health professionals dealing with obese clients and is NOT a self-management tool or weight-loss program. However, I assume that even general readers may find some of this material of interest.
Abdominal obesity is now widely recognized as being an independent risk factor for cardiovascular disease, as it promotes hypertension as well as glucose and lipid abnormalities, all of which increase cardiovascular risk. It is therefore not surprising that obesity is often associated with high blood pressure, ischemic heart disease, stroke, type 2 diabetes, and dyslipidemia. Obesity has also been associated with several non-traditional risk factors, such as disturbance of fibrinolysis, impaired endothelial function, and chronic low-grade inflammation. It is interesting that a significant subset of obese patients appear to be metabolically healthy, and the assumption is that their expanded subcutaneous adipose tissue acts as a “metabolic sink” and protects them from the cardio-metabolic consequences of obesity.
Obesity is associated with left ventricular hypertrophy that is not just related to concomitant hypertension. Increases in stroke volume, cardiac output, and diastolic dysfunction are seen in obese patients even without hypertension. The right ventricle also changes as a result of left ventricular dysfunction or the coexistence of obstructive sleep apnea or hypoventilation syndrome. For all of these reasons, heart failure in obesity is generally biventricular.
Obesity is not only related to hemodynamic and structural changes in the heart, but it can also predispose to arrhythmias and might be a predisposing factor for sudden death. Risk factors for obesity-related arrhythmias include left ventricular hypertrophy, congestive heart failure, autonomic imbalance, and sleep apnea.
Obesity contributes to chronic venous stasis disease of the lower extremities, as it increases abdominal pressure and leads to impaired venous and lymphatic return. Morbidly obese patients are at increased risk for edema and lymphedema in the lower extremities, stasis ulcers, thrombophlebitis, deep venous thrombosis and pulmonary thromboembolism.
Unfortunately, morbidly obese patients are less likely to receive appropriate diagnosis and treatment as adequate diagnostic equipment for these patients is not always available. Most cardiac diagnostic equipment is not suitable for patients who weigh more than 181.5 kg (400 lbs).
It is important to identify obese patients who are particularly at risk for cardiovascular complications. History and physical exam should address symptoms and signs of organ damage (coronary artery disease, peripheral vascular disease, congestive heart failure) and diagnostic procedures should be performed where indicated. It is also important to recognize that cardiovascular problems such as angina, exertional dyspnea and intermittent claudication can promote weight gain by making exercise more difficult and potentially risky. Reduced capacity for physical activity is particularly relevant in patients who have suffered paralytic strokes.
You should ascertain a patient’s family history of diabetes and premature cardiovascular disease as well as their physical activity status. As well, the following risk factors for cardiovascular disease should be thoroughly explored in all obese patients.
© Copyright 2010 by Dr. Arya M. Sharma and Dr. Yoni Freedhoff. All rights reserved.
The opinions in this book are those of the authors and do not represent those of the Canadian Obesity Network.
Members of the Canadian Obesity Network can download Best Weight for free.