Invited Commentary

Abstract

Major public health consequences have evolved from the obesity epidemic in the United States and worldwide. It has been estimated that approximately 30% of the adult population in the United States is classified as obese, defined as a body mass index (BMI) > 30 kg/m2. Obesity is an independent risk factor for cardiovascular disease (CVD) and is related to a constellation of comorbidities, such as hypertension (HTN), dyslipidemia, type II diabetes mellitus (DM), inflammation, thrombosis, renal dysfunction, and the insulin resistant syndrome [1Lamon-Fava S. Wilson P.W.F. Schaefer E.J. Impact of body mass index on coronary heart disease risk factors in men and women: the Framingham Offspring Study.Arterioscler Thromb Vasc Biol. 1996; 16: 1509-1515Crossref PubMed Scopus (266) Google Scholar, 2Krauss R.M. Winston M. Fletcher B.J. et al.Obesity: impact on cardiovascular disease.Circulation. 1998; 98: 1472-1476Crossref Scopus (402) Google Scholar, 3Visscher T.L. Seidell J.C. The public health impact of obesity.Annu Rev Public Health. 2001; 22: 355-375Crossref PubMed Scopus (743) Google Scholar, 4Eckel R.H. Barouch W.W. Ershow A.G. Report of the National Heart, Lung, and Blood Institute-National Institute of Diabetes and Digestive and Kidney Diseases Working Group on the pathophysiology of obesity-associated cardiovascular disease.Circulation. 2002; 105: 2923-2928Crossref PubMed Scopus (199) Google Scholar]. Statistically, there is a significant increase of younger obese men and women who die from CVD when compared with people who have a normal BMI. In fact, for every 1 kg/m2 increase in BMI, there is a 4% increase in the percentage of myocardial infarct, a 3% increase in CVA, a 6% increase in HTN, an 8% increase in venous thrombotic emboli, and a 5% increase in atrial fibrillation [5Murphy N.F. MacIntyre K. Stewart S. Hart C.L. Hole D. McMurray J.J.V. Long-term cardiovascular consequences of obesity; 20 year follow-up of more than 1500 middle aged men and women (The Renfrew-Paisley Study).Eur Heart J. 2006; 27: 96-106Crossref PubMed Scopus (236) Google Scholar].Older, surgical literature reported increased BMI as a risk factor for new onset atrial fibrillation, wound infections, increased intensive care (ICU) unit days and 30-day mortality [6Zacharias A, Schwann TA, Riordan CJ, Durham SJ, Shah AS, Habib RH. Obesity and risk of new-onset atrial fibrillation after cardiac surgery. Circulation 2885;112:3247–55.Google Scholar, 7Harrington G. Russo P. Spelman D. et al.Surgical-site infection rates and risk factor analysis in coronary artery bypass graft surgery.Infect Control Hosp Epidemiol. 2004; 25: 472-476Crossref PubMed Scopus (128) Google Scholar, 8Abboud C.S. Wey S.B. Baltar V.T. Risk factors for mediastinitis after cardiac surgery.Ann Thorac Surg. 2004; 77: 676-683Abstract Full Text Full Text PDF PubMed Scopus (158) Google Scholar]. However, the association between obesity and increased morbidity and mortality after coronary artery bypass grafting (CABG) remains mixed in recent articles. Rockx and colleagues [9Rockx M.A. Fox S.A. Stitt L.W. et al.Is obesity a predictor of mortality, morbidity and readmission after cardiac surgery?.Can J Surg. 2004; 47: 34-38PubMed Google Scholar] and Villancencio and colleagues [10Villancencio M.A. Sundt T.M. Doly R.C. et al.Cardiac surgery in patients with BMI of 50 or greater.Ann Thorac Surg. 2007; 83: 1403-1411Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar] reported that increased BMI was not a predictor for major perioperative complications, except for increased ICU days. In fact, lower BMI was a greater risk factor for increased risk of perioperative complications than obesity.The majority of published articles report obesity (BMI ≥ 30) as a homogeneous group of patients with fixed risk factors, which is not a statistical reality. This article [11Sun X. Hill P.C. Bafi A.S. et al.Is cardiac surgery safe in extremely obese patients (body mass index 50 or greater)?.Ann Thorac Surg. 2009; 87: 540-547Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar] reviewed a subset of patients with extreme obesity (BMI ≥ 50) to assess the effect of this BMI subset on surgical morbidity and mortality after open heart surgery (OHS). Sun and colleagues [11Sun X. Hill P.C. Bafi A.S. et al.Is cardiac surgery safe in extremely obese patients (body mass index 50 or greater)?.Ann Thorac Surg. 2009; 87: 540-547Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar] reported a series of 57 extremely obese patients (BMI ≥ 50) with a mean age of 58 years; mean BMI ≥ 55; 63% women; 52% African American; and a significant incidence of HTN, DM, and short height. Elective CABG was done in 72% of the patients while the remainder were nonelective. Approximately 50% of all CABG was done off-pump. Using a multi-variant analysis, extreme obesity did not emerge as a significant risk factor for operative mortality and other adverse outcomes after elective surgery. Extreme obesity was associated with increased mortality and as a risk factor for longer ICU days in overall surgery. In the subset analysis, the mortality of patients with extreme obesity was also not significantly different from normal BMI patients undergoing elective CABG and isolated coronary bypass surgery. There were five mortalities (all women); only two of which were related to coronary artery disease, and the other three were valvular heart disease.Improvements in preoperative evaluation, intraoperative technique, and postoperative care can optimize the results with this high risk subset of patients with cardiovascular disease. Extremely obese patients can be offered elective CABG with a safe and acceptable risk profile when compared with patients who had normal BMIs. Obese patients risk profiles for morbidity and mortality will continue to evolve as surgeons collect, analyze, and report their data. The authors need to be commended on the formable surgical challenge of performing cardiac surgery on these extremely obese patients and having excellent results. Extremely obese patients remain a very high-risk group as defined by their 1-year mortality of 82.5% compared with all other levels of BMI. Major public health consequences have evolved from the obesity epidemic in the United States and worldwide. It has been estimated that approximately 30% of the adult population in the United States is classified as obese, defined as a body mass index (BMI) > 30 kg/m2. Obesity is an independent risk factor for cardiovascular disease (CVD) and is related to a constellation of comorbidities, such as hypertension (HTN), dyslipidemia, type II diabetes mellitus (DM), inflammation, thrombosis, renal dysfunction, and the insulin resistant syndrome [1Lamon-Fava S. Wilson P.W.F. Schaefer E.J. Impact of body mass index on coronary heart disease risk factors in men and women: the Framingham Offspring Study.Arterioscler Thromb Vasc Biol. 1996; 16: 1509-1515Crossref PubMed Scopus (266) Google Scholar, 2Krauss R.M. Winston M. Fletcher B.J. et al.Obesity: impact on cardiovascular disease.Circulation. 1998; 98: 1472-1476Crossref Scopus (402) Google Scholar, 3Visscher T.L. Seidell J.C. The public health impact of obesity.Annu Rev Public Health. 2001; 22: 355-375Crossref PubMed Scopus (743) Google Scholar, 4Eckel R.H. Barouch W.W. Ershow A.G. Report of the National Heart, Lung, and Blood Institute-National Institute of Diabetes and Digestive and Kidney Diseases Working Group on the pathophysiology of obesity-associated cardiovascular disease.Circulation. 2002; 105: 2923-2928Crossref PubMed Scopus (199) Google Scholar]. Statistically, there is a significant increase of younger obese men and women who die from CVD when compared with people who have a normal BMI. In fact, for every 1 kg/m2 increase in BMI, there is a 4% increase in the percentage of myocardial infarct, a 3% increase in CVA, a 6% increase in HTN, an 8% increase in venous thrombotic emboli, and a 5% increase in atrial fibrillation [5Murphy N.F. MacIntyre K. Stewart S. Hart C.L. Hole D. McMurray J.J.V. Long-term cardiovascular consequences of obesity; 20 year follow-up of more than 1500 middle aged men and women (The Renfrew-Paisley Study).Eur Heart J. 2006; 27: 96-106Crossref PubMed Scopus (236) Google Scholar]. Older, surgical literature reported increased BMI as a risk factor for new onset atrial fibrillation, wound infections, increased intensive care (ICU) unit days and 30-day mortality [6Zacharias A, Schwann TA, Riordan CJ, Durham SJ, Shah AS, Habib RH. Obesity and risk of new-onset atrial fibrillation after cardiac surgery. Circulation 2885;112:3247–55.Google Scholar, 7Harrington G. Russo P. Spelman D. et al.Surgical-site infection rates and risk factor analysis in coronary artery bypass graft surgery.Infect Control Hosp Epidemiol. 2004; 25: 472-476Crossref PubMed Scopus (128) Google Scholar, 8Abboud C.S. Wey S.B. Baltar V.T. Risk factors for mediastinitis after cardiac surgery.Ann Thorac Surg. 2004; 77: 676-683Abstract Full Text Full Text PDF PubMed Scopus (158) Google Scholar]. However, the association between obesity and increased morbidity and mortality after coronary artery bypass grafting (CABG) remains mixed in recent articles. Rockx and colleagues [9Rockx M.A. Fox S.A. Stitt L.W. et al.Is obesity a predictor of mortality, morbidity and readmission after cardiac surgery?.Can J Surg. 2004; 47: 34-38PubMed Google Scholar] and Villancencio and colleagues [10Villancencio M.A. Sundt T.M. Doly R.C. et al.Cardiac surgery in patients with BMI of 50 or greater.Ann Thorac Surg. 2007; 83: 1403-1411Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar] reported that increased BMI was not a predictor for major perioperative complications, except for increased ICU days. In fact, lower BMI was a greater risk factor for increased risk of perioperative complications than obesity. The majority of published articles report obesity (BMI ≥ 30) as a homogeneous group of patients with fixed risk factors, which is not a statistical reality. This article [11Sun X. Hill P.C. Bafi A.S. et al.Is cardiac surgery safe in extremely obese patients (body mass index 50 or greater)?.Ann Thorac Surg. 2009; 87: 540-547Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar] reviewed a subset of patients with extreme obesity (BMI ≥ 50) to assess the effect of this BMI subset on surgical morbidity and mortality after open heart surgery (OHS). Sun and colleagues [11Sun X. Hill P.C. Bafi A.S. et al.Is cardiac surgery safe in extremely obese patients (body mass index 50 or greater)?.Ann Thorac Surg. 2009; 87: 540-547Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar] reported a series of 57 extremely obese patients (BMI ≥ 50) with a mean age of 58 years; mean BMI ≥ 55; 63% women; 52% African American; and a significant incidence of HTN, DM, and short height. Elective CABG was done in 72% of the patients while the remainder were nonelective. Approximately 50% of all CABG was done off-pump. Using a multi-variant analysis, extreme obesity did not emerge as a significant risk factor for operative mortality and other adverse outcomes after elective surgery. Extreme obesity was associated with increased mortality and as a risk factor for longer ICU days in overall surgery. In the subset analysis, the mortality of patients with extreme obesity was also not significantly different from normal BMI patients undergoing elective CABG and isolated coronary bypass surgery. There were five mortalities (all women); only two of which were related to coronary artery disease, and the other three were valvular heart disease. Improvements in preoperative evaluation, intraoperative technique, and postoperative care can optimize the results with this high risk subset of patients with cardiovascular disease. Extremely obese patients can be offered elective CABG with a safe and acceptable risk profile when compared with patients who had normal BMIs. Obese patients risk profiles for morbidity and mortality will continue to evolve as surgeons collect, analyze, and report their data. The authors need to be commended on the formable surgical challenge of performing cardiac surgery on these extremely obese patients and having excellent results. Extremely obese patients remain a very high-risk group as defined by their 1-year mortality of 82.5% compared with all other levels of BMI. Is Cardiac Surgery Safe in Extremely Obese Patients (Body Mass Index 50 or Greater)?The Annals of Thoracic SurgeryVol. 87Issue 2PreviewWe investigated the impact of extreme obesity (body mass index [kg/m2] 50 or greater) on short-term clinical outcomes and report 1-year mortality. Full-Text PDF