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Reduction of Biochemical Cardiac Risk Factors
Abstract & Commentary
By, Nicole R. Basa, MD, Clinical Instructor, Department of Surgery, UCLA Division of Minimally Invasive and Bariatric Surgery. Dr. Basa reports no financial relationships relevant to this field of study.
Synopsis: Gastric Bypass improves patient risk for Coronary Artery Disease.
Source: Williams DB, et al. Gastric bypass reduces biochemical cardiac risk factors. Surg Obes Relat Dis. 2007;3:8-13.
Background: Coronary Artery Disease (CAD) is a major health problem throughout the world. It is the leading cause of death in the United States. There are 2 primary, modifiable risk factors for CAD, including tobacco use and obesity. Tobacco use has demonstrated a decline in the United States, but obesity has continued to increase. The only effective, long-term treatment for morbid obesity is the gastric bypass.
The gastric bypass not only results in long-term weight loss, but it has also resulted in a reduction in cardiac risk, as well as survival benefit, as compared with morbidly obese controls. Many biochemical markers are correlated with the severity of CAD. These markers include total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride level, lipoprotein A, C-reactive protein (CRP), and homocysteine.
Methods: Between 2003-2004, biochemical cardiac risk factors were measured at a single institution after gastric bypass at 3,6, and 12 months postoperatively. The data was analyzed using the Wilcoxon signed rank test.
Results: Three hundred fifty-six total patients were analyzed. There was significant improvement in HDL, LDL, total cholesterol/HDL ratio, triglycerides, lipoprotein A, C-reactive protein, and homocysteine.
Conclusions: Gastric bypass improves biochemical markers of CAD and decreases cardiac risk by both weight loss and improvement of biochemical markers.
This study consisted of a sample size of 356 patients at one year follow-up. The preoperative demographics consisted of 84% women, with comorbidities including diabetes (33%), hypertension (50%), and known CAD (3%). Twenty-three percent of patients were on antilipid medications such as statins. Postoperatively, these patients were not restarted on their lipid-lowering medications. Findings demonstrated a statistically significant improvement in lipid profile. Dramatic reduction occurred as well in CRP, lipoprotein A, and homocysteine levels.
CRP level, which is the single best measure of cardiac risk, was elevated in 80% of the patients in the study. The CRP level is a strong independent predictor of future myocardial infarction, stroke, and peripheral arterial disease in a healthy population.1-3 After statin therapy, CRP reduction has a greater impact than LDL cholesterol reduction on cardiovascular risk.4 In the patients enrolled in the study, 80% had elevated CRP. This may be due to a strong correlation between BMI and CRP levels. The strong correlation may also demonstrate the many inflammatory disorders, which include diabetes, DJD, and depression, found in the morbidly obese patient. Gastric bypass surgery reduced the CRP level by 80%, whereas statins only improved CRP by 16.9% within a similar time period.5
This study demonstrates nicely the improvement in cardiac risk factors by measuring biochemical markers before and after surgery. Improvement in cardiac risk factors may not only lead to improved cardiac status but may also lead to other downstream benefits, which include prevention of peripheral vascular disease and the development of prostate and endometrial cancers. Overall, this study objectively shows how gastric bypass improves one's lipid profile. This, in turn, decreases one's weight and risk for developing metabolic syndrome, which is comprised of abdominal obesity, hypertension, hyperglycemia, and hyperlipidemia. Metabolic syndrome is an inflammatory disease which may be represented by the inflammatory marker CRP. As this study shows, CRP is markedly reduced after gastric bypass surgery.
1. Ridker PM. High-sensitivity C-reactive protein: Potential adjunct for global risk assessment in the primary prevention of cardiovascular disease. Circulation. 2001;103:1813-1818.
2. Ridker PM, et al. Plasma concentration of C-reactive protein and risk of developing peripheral vascular disease. Circulation. 1998;97:425-428.
3. Ridker PM, et al. Comparison of C-reactive protein and low-density lipoprotein cholesterol levels in the prediction of first cardiovascular events. N Engl J Med. 2002;347:1557-1565.
4. Ridker PM, et al. C-reactive protein levels and outcomes after statin therapy. N Engl J Med. 2005;352:20-28.
5. Albert MA, et al. Effect of statin therapy on C-reactive protein levels: The pravastatin inflammation/CRP evaluation (PRINCE): A randomized trial and cohort study. JAMA. 2001;286:64-70.