Ask The Doctors: May 2018
Q: I have been taking fish oil supplements for years, ever since I was told fish oil would prevent heart disease. Now I hear that this is not the case. Should I stop taking it?
A: In 2002, the American Heart Association recommended that patients with coronary heart disease (CHD) consume 1 gram daily of marine-derived omega-3 fatty acids containing EPA plus DHA, preferably from oily fish. Supplements are okay if you don’t like fish. In 2012, 8 percent of adults in the United States were taking fish oil supplements. However, fatty acids may have gained their heart-healthy reputation in the absence of strong evidence. Only one clinical trial reported benefit in patients with heart failure, and there is little evidence to support its benefit for primary prevention.
A recent large meta-analysis of 10 fatty acid trials involving approximately 78,000 people with or at high risk for cardiovascular disease found no significant reduction in CHD or other major CVD events, although there was a small 7 percent reduction in CHD death. A major unanswered question is whether fatty acid supplementation reduces CVD events in people without CVD. An ongoing trial is addressing this issue. Also, two large trials are assessing the impact of high doses of fatty acids on high-risk CVD patients with elevated triglyceride levels.
While awaiting these trial results, it makes the most sense to consume fatty acids by eating fresh fish two to three times a week (or plant-based sources of omega-3s). If you use supplements, check the amount of fatty acids they contain, as there is great variability.
Currently, the American Heart Association states that fatty acid supplements are reasonable in patients with prior CHD or heart failure, not recommended routinely in patients with diabetes or for primary prevention of stroke, and that no recommendation can currently be made for primary prevention of CVD.
Q: What is the purpose of a coronary artery calcium (CAC) score? Mine is 610. Should I worry about a heart attack? Should I have a procedure to remove the calcium?
A: Calcification is part of the inflammation and repair process when atherosclerosis is present. CAC is a marker of coronary plaque burden and future risk, not the degree of coronary obstruction. If you have had a prior heart attack or revascularization, a CAC score wouldn’t add much, since we already know you are at high risk. In someone with a strong family history of heart attack and multiple risk factors, but without a personal history of heart disease, CAC can be used to refine the prediction of future heart events and guide preventive treatment.
An abnormal CAC score is anything above the 75th percentile for your age, gender and ethnicity, or an absolute score of 300 Agatston units or more. A high score might trigger your doctor to obtain a stress test to exclude compromised blood flow to the heart, but is not by itself an indication for heart catheterization, angioplasty or coronary artery bypass surgery.
You can use the MESA scoring system (www.mesa-nhlbi.org/CACReference.aspx) to determine your 10-year heart risk. Let’s assume your cholesterol is 185 milligrams per deciliter (mg/dL) and your blood pressure is 132/78 millimeters of mercury (mm Hg) on medications. Your 10-year risk of heart attack is 22 percent. Since your CAC score is also high, you would be a candidate for aggressive prevention with a high-intensity statin to lower your LDL cholesterol below 70 mg/dL, medications to bring your blood pressure below 130/80 mm Hg, aspirin, exercise and a healthy diet, not procedures to remove plaque or calcium. Stenting or bypass surgery might help if you have had a heart attack or symptoms, but would likely not extend your life or prevent you from having a future heart attack.