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Question:
Should I have a treadmill/nuclear scan every year? Is a lipid panel still the best way to predict potential blockage?
My history: Age 75. Very active. A runner for 20 years from ages 40-60. Ran 30,000 miles and competed in numerous marathons. My company physician . . . told me that I was at the lowest risk for heart disease primarily because of an HDL=70-90. However, at age 68 I had to have a stent put in my LAD. . . . Nuclear scans/treadmills every 2 years showed no ischemia for the next 5 years. I was scheduled for a scan/treadmill last Dec but, prior to that (Thanksgiving day), I had to go to the emergency room [for] . . . atrial fibrillation. An echocardiogram . . . led to heart cath and stenting two more arteries. After a month I started going to an electrophysiologist and he did cardioversion and my heart reverted to a normal rythym. Four weeks ago I had a treadmill and nuclear scan. Actually, because I am on sotolol, I could not produce the desired heart rate so my blood vessels were chemically dilated for the scan. A week later, my cardiologist told me that my scan revealed that all my arteries are open and clean. However he said that there was evidence . . . [of] a mild infarction. . . . At this meeting with my cardiologist I asked him why he didn't give me a treadmill/nuclear scan every year. . . . [he] said that having these tests every year would subject me to more radiation and increase my prospects of cancer. My questions are: . . . which risk is more significant, a blockage and, possibly an infarction or radiation cancer? Are there any other tests without radiation exposure that can show a possibility of blockage and the need for a heart cath?
Incidentally . . . my cardiologist said he wanted me to get my LDL to 70 or below. I had been prescribed and taking 10mg of Crestor since last Thanksgiving. He ordered a blood test which showed : HDL=61 and LDL=102 Cholesterol=180. After seeing this lipid panel, the cardiologist decided to leave me at 10mg of Crestor. I have read that the lipid panel is not necessarily the best way to predict the potential of blockage. . . . Do you concur with conjecture that there are better blood tests than the lipid profile for predicting the potential for blockage? I am really thankful to find this web site and I look forward to your reply. [Edited for brevity.]
submitted by Jack from Siloam Springs, Arkansas, on 11/14/09
Answer:
by Texas Heart Institute cardiologist, Christopher M. Frank, MD
There are two basic questions here; the first is about the appropriate way of monitoring patients with known coronary artery disease. There are no studies that have ever shown that asymptomatic patients who are routinely monitored with stress tests have a lower probability of heart attack or death, so the appropriate interval at which to monitor patients is something of a matter of opinion - and of course frequent monitoring is associated with both financial cost and the risks of radiation exposure. Based in part on the standard practice that has evolved over time, in 2005, the American College of Cardiology released "appropriateness criteria" that state that asymptomatic patients should not have stress testing with nuclear imaging more often than every two years, so a physician who did so every year would clearly not be in the mainstream of American medicine (and would probably not be reimbursed by an insurer). Some physicians, in fact, would take the position that patients without symptoms and with a normal exercise tolerance should not have stress tests at any interval. Remember that stents (in stable patients) have only been proven to treat symptoms and not to prevent heart attacks or death.
The second question is about the optimal medical therapy for coronary artery disease. Essentially all patients with coronary disease should be on an aspirin, and patients who have had recent stents or have severe disease in multiple arteries are usually on another antiplatelet agent (like clopidogrel or Plavix) as well. Patients who have had prior myocardial infarctions are usually placed on beta blockers in order to decrease the risk of dangerous arrhythmias, and obviously smoking increases risks. Finally, the cornerstone of medical therapy for coronary disease is improving the lipid panel. The data strongly support achieving a goal for LDL cholesterol under 100 mg/dL, and probably a goal of under 70 mg/dL for the optimal benefit; in my own practice if patients have been stable for a long period of time I'll tolerate a level of 100 but if they have had recent events or events despite medical therapy I'll definitely aim for a level of under 70. As a secondary goal, most physicians would recommend increasing HDL if possible (often with niacin) and lowering non-HDL cholesterol. It's true that in recent years there have been other approaches to risk stratification studied, including measurement of HDL subfractions, measurement of apolipoprotein B, Lp (a), and a variety of other tests. Some of these tests, at least in the trials in which they've been studied, do predict coronary events slightly better than the traditional tests, but in general this doesn't have major clinical implications for patients with coronary disease - at most they may be helpful in targeting the precise dose of medications required or in deciding whether an otherwise healthy young patient with no symptoms or no coronary disease really needs lifelong medical therapy. I rarely, if ever, use them in my own practice.
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Updated November 2009
