January 6, 2014
The new cardiovascular prevention guidelines from the American Heart Association and the American College of Cardiology provide a great opportunity for us to start a discussion with our patients about their risk of atherosclerotic vascular disease (ASCVD) and steps they can take to reduce it. Even though deaths from cardiovascular disease have been declining, one in three Americans will die from heart disease or stroke, and these diseases place a huge burden on our patients and their families in terms of disability, hospitalizations and costly medical procedures.
While there are some concerns about the way the ASCVD risk calculator was developed, the new guidelines are an important step forward in prevention. We know that we can prevent or delay the vast majority of heart attacks and strokes with a combination of lifestyle modifications and, when appropriate, a statin. Indeed, we should evaluate the individual ASCVD risk for all of our patients so that they can take steps to reduce their risk.
The new risk calculator will prompt many clinicians to look more closely at their patients’ risk factors, including cholesterol, blood pressure, glycemic control and smoking history, even though they may have seemingly normal LDL cholesterol values. At Johns Hopkins' Ciccarone Center for the Prevention of Heart Disease, we believe that a family history of early-onset cardiovascular disease is also an important ingredient to add to the risk recipe.
Since the new guidelines recommend statin medications for specific groups heavily weighted by age, we think that closer evaluation of individual patients in these groups with borderline ASCVD risk estimates of 5 to 10 percent over the next decade may be warranted before prescribing a statin. If we are on the fence about whether statin and aspirin therapy would be beneficial for those patients, a coronary calcium score would be the best tie-breaker. It has the most science behind it.
For example, not all adults ages 40 to 75 with diabetes have plaque in their coronary arteries. According to the Multi-Ethnic Study of Atherosclerosis, about 35 percent of middle-aged patients with diabetes did not have evidence of coronary artery calcification (CAC) and had a very low event rate over the ensuing seven years. Our research also indicates that individuals with multiple risk factors but no CAC have a much lower absolute risk compared with those with no traditional risk factors but an elevated CAC score of greater than 100.
Some colleagues believe that the new risk calculator overestimates risk for many patients. However, our prevention goals must go beyond preventing heart attack, stroke and mortality to reducing our patients’ risk of angina, peripheral arterial disease and the need for invasive revascularization measures.
The new guidelines make prevention a focus for patients and clinicians. We should remember that guidelines are just that— not hard and fast rules. We must continue to evaluate individual patients on their particular risk profiles and emphasize the importance of a healthy lifestyle for everyone as the first line of defense against cardiovascular disease.