Dr. Emily G. Kurtz
Two Tests Favored to Further Examine At-Risk Heart Patients
When it comes to predicting who’s at risk for cardiovascular disease, some factors are etched in evidence-based stone. They include advanced age, gender (male), high blood pressure, high cholesterol, obesity, smoking and diabetes. Yet is that the end of the list, or just the beginning?
“What has been noted over the last several years is that these calculators, while they are well-validated and useful, are limited in the sense that they are heavily weighted by age, they don’t predict all that well in young people, and they don’t include a family history of heart disease,” said Emily G. Kurtz, MD, director of preventive cardiology at the Vanderbilt Heart and Vascular Institute. Thus, she said, these factors are valuable to predict short-term cardiovascular risk, but they aren’t as predictive over the long haul and may not catch a problem in time to nip it in the bud.
That’s the juggernaut that the preventive cardiology community wrestles with today. When should extra tests be ordered, and which tests aren’t too expensive yet might offer information that could change a treatment protocol?
AHA’s Three Categories
The American Heart Association recently published evidence-based guidelines for risk stratification that categorize patients as high-risk, at risk or ideal. For high-risk individuals, treatment is obvious, while patients deemed in “ideal cardiovascular health” need no intervention. It’s those patients in the intermediate, “at-risk” category who are problematic – and who keep people like Kurtz and David C. Huneycutt, MD, a Centennial Heart cardiologist, up at night.
“A traditional approach still holds true,” Honeycutt said, “but now we have some complementary approaches, some of which haven’t yet entered the mainstream in terms of whether or not they’re truly going to end up being beneficial.” Yet data exists that indicate some of these unconventional alternatives just might save a life.
According to the AHA, an individual is “at risk” if he or she has just one of these risk factors:
• Cigarette smoking
• A systolic blood pressure above 120 mm Hg, a diastolic BP above 80 mm Hg or treated hypertension
• Total cholesterol above 200 mg/dL, an HDL level below 50 mg/dL or treated dyslipidemia
• Obesity, especially belly fat
• Poor diet
• Physical inactivity
• Family history of premature heart disease in first-degree relatives (men younger than 55 or women younger than 65)
• Metabolic syndrome
• Evidence of subclinical atherosclerosis, such as coronary artery calcification or carotid artery plaque
• Poor exercise capacity on a treadmill test and/or abnormal heart-rate recovery after stopping exercise
• Systemic autoimmune collagen-vascular disease, such as lupus or rheumatoid arthritis
• History of preeclampsia, gestational diabetes or pregnancy-induced hypertension
Kurtz said she adds erectile dysfunction to this list, and Huneycutt agreed, saying ED could be a “first clue” that atherosclerosis exists, since the penile arteries are smaller than coronary arteries.
The Next Step
“We try to be selective about who might need further testing in addition to just using traditional risk factors. When there’s uncertainty about how aggressively to treat a patient, that’s when we tend to consider novel cardiovascular diagnostic testing,” Kurtz explained.
Two tests commonly used to further examine patients in the at-risk category are:
1. a measurement of high-sensitivity C-reactive protein in the blood and
2. coronary artery calcium scoring.
C-reactive protein is a common, stable marker that indicates inflammation. “Clearly, inflammation has a role in the development of atherosclerosis,” Honeycutt said. “The formation of plaque in arteries involves not only cholesterol influx into the inner layer of the heart arteries and arteries elsewhere, but it also involves the conversion of certain immune cells within this plaque into an active cell that makes and releases certain local chemicals that cause these cells to take on more lipids. The inflammation there can also be part of the pathology that leads to these plaques rupturing open and causing heart attacks.”
Added Kurtz, “It turns out that the high-risk, life-threatening coronary lesion is not necessarily the one that’s the most blocked; rather, it’s the lesion having the most active state of inflammation, which can make it vulnerable to rupture.”
Coronary artery calcium scoring is a low-radiation, noncontrasting CT scan of the chest with a dedicated evaluation of the coronary arteries for calcified plaque. “It’s a good test in selected patients, but it is not recommended that everyone have one of these, especially young people,” said Huneycutt, who specializes in advanced cardiac imaging. “I think most cardiologists would say that this is a test typically reserved for patients in their late 40s and 50s, where the decision to institute therapy would be affected by the results.” That therapy many times would be the introduction of a statin.
Huneycutt said these novel, unconventional tests still await more comprehensive clinical trials. “These things are in a state of evolution,” he said.
Meanwhile, patients need “a good quarterback,” Kurtz said. “That’s the primary care physician. And patients need to know their numbers – their cholesterol, blood sugar, blood pressure and BMI in comparison with ideal levels. Then the primary care physician can look at their lifestyle and help initiate therapeutic lifestyle interventions like exercise, avoiding tobacco use and maintaining an ideal weight and heart-healthy diet.”
Managing these risk factors, she said, is still tried and true prevention.