CardioSource WorldNews December 2014 - Page 35

• angiography often does not demonstrate plaque rupture with associated thrombus. Once high-sensitivity cardiac troponin assays become widespread, one challenge will be distinguishing ACS from biological processes that also cause changes in troponin. The prototypical example is in the setting of acute HF where you can see a rise and fall of troponin that is not indicative of ACS. As Dr. Jaffe explained, “There is going to be a time where almost every patient with acute heart failure will have a rising pattern of cardiac troponin, so they will have met the criteria in terms of showing a rise and or a fall in troponin but they are not patients we should say are having a myocardial infarction.” TREATMENT: UNCLEAR If a type 2 MI is suspected, the problem then becomes what do you do about? At this time, the third universal definition authors admit there is a dearth of information on which to base clinical decisions in this setting. Cardiac catheterization almost certainly is associated with significant risk in such critically ill patients, as is antithrombotic therapy. Often, beta-blockers, nitrates, and low-dose aspirin are given, but without strong evidence indicating that this is beneficial. Clinical research involving patients with type 2 MI or myocardial injury is needed desperately to assist in differentiating these entities and determining what, if any, specific therapy is indicated. REFERENCES: 1. Thygesen K, Alpert JS, Jaffe AS, et al. J Am Coll Cardiol. 2012;60:1581-98. http://content.onlinejacc.org/article. aspx?articleid=1367084 2. Alpert JS, Thygesen K. Circulation.2006;114:757-8. 3. Alpert JS, Thygesen K; on behalf of the Joint ESC/ACC Committee. J Am Coll Cardiol. 2000; 36: 959-69. http:// content.onlinejacc.org/article.aspx?articleid=1126658 4. Thygesen K, Alpert JS, White HD. J Am Coll Cardiol. 2007;50:2173-95. http://content.onlinejacc.org/article. aspx?articleid=1138690 5. Alpert JS, Thygesen KA, White HD, Jaffe AS. Am J Med. 2014;127:105-8. Take-aways • Distinguishing type 1 from type 2 MI has been the subject of considerable clinical discussion and confusion. • A type 1 MI is usually the result of atherosclerotic CAD with thrombotic coronary arterial obstruction secondary to atherosclerotic plaque rupture, ulceration, fissuring, or dissection, causing coronary arterial obstruction with resultant myocardial ischemia and necrosis. • Patients with a type 2 MI do not have atherosclerotic plaque rupture. In this latter group of patients, myocardial necrosis occurs because of an increase in myocardial oxygen demand or a decrease in myocardial blood flow. CardioSource.org/CSWN When Does Obesity Shorten Life Expectancy? T he increasing prevalence of overweight and obesity is alarming given their association with death, disability, and disease. However, it is difficult to estimate the public health impact of excess weight because of its complex interactions with age, smoking, and obesity-related risk factors such as diabetes, hypertension, and lipid disorders. Even family history seems to play a role. In a 50-year prospective study of Framingham participants, investigators determined that being obese when you are age 40 diminishes life expectancy by about 7 years.1 For obese people who smoke, the prognosis is even worse: they typically die 13-and-a-half years before their time. Framingham data also tell us that measuring the total effect of obesity by combining its level (body mass index [BMI] units above 29 kg/m2) multiplied by the duration of obesity into a single metric of “obese-years” is a stronger predictor for the risk of CVD compared to using duration of obesity or level of obesity alone. Recently, investigators observed a clear dose-response relationship between obese-years and risk of CVD. A stronger effect was found in males than in females.2 This is especially alarming given the increasing incidence of overweight and obesity in children. Early in 2014, investigators reported data from the Early Childhood Longitudinal Study, a prospective cohort of 7,738 participants who were in kindergarten in the United States in 1998.3 Fully 12.4% of kids entering kindergarten were obese and another 14.9% were overweight. While some of these kids “grew into” more normal weights, subsequent incident obesity between the ages of 5 and 14 occurred primarily among those children who had entered kindergarten overweight. DRAMATIC REDUCTION IN LIFE EXPECTANCY In the summer of 2014, the NIH reported the results of a study evaluating the risk of premature death associated with extreme obesity. In the U.S., 6% of adults are now classified as extremely obese, which, for a person of average height, is more than 100 pounds over the recommended range of normal weight. Investigators pooled data from 20 large studies of people from three countries.4 The final sample included 9,564 extremely obese adults and 304,001 healthy-weight adults, making it the largest-ever study of its kind. Overall risk of mortality as well as risk of mortality from most major health causes rose continuously with increasing BMI within the class III obesity (BMI 40 to 59 kg/m) group. Years of life lost ranged from 6.5 years for participants with a BMI of 40 to 44.9 to 13.7 years for a BMI of 55 to 59.9. To provide context, the number of years of life lost for class III obesity was equal or higher than that of current (versus never) cigarette smokers among normal-weight participants in the same study. According to Patricia Hartge, ScD, senior author of the study, “Given our findings, it appears that class III obesity is increasing and may soon emerge as a major cause of early death in this and other countries worldwide.” THERE IS GOOD NEWS Robert H. Eckel, MD, said the data really do illustrate the dangers of extreme obesity, but the good news is that being overweight, defined as a BMI of 25.0 to 29.9, does not influence life expectancy “one iota.” However, as BMI increases, particularly once it is beyond 35, “it is pretty clear that obesity impacts life expectancy.” Most of this increased mortality is CVD-related. So, if you are looking for cutoffs that matter in terms of mortality, a BMI > 35 appears to be an important one. The exception: age 70 years and older. “There’s something about extra b