Everyone’s heard of a patient who had a “normal” stress test but later had to have stents or surgery or even suffered a heart attack. The rates of cardiac death or myocardial infarction after a normal nuclear stress test are low but not zero (Circulation 1998;97:535-43). Up to 40 percent of coronary angiograms reveal minor or no disease (J Am Coll Cardiol 2012;59:2221-305). It's time for precision in the management of stable chest pain.
Although precision has become a buzzword, being precise is exactly what we want in cardiology. We want to use the right tests and treatments for the right patients. Many patients with “abnormal” stress tests turn out to have normal coronary arteries. Some of this “low yield” from coronary angiography reflects the fact that our gold standard for noninvasive testing is only 75-85 percent sensitive or specific (Circ Cardiovasc Imaging 2009;2:412-24; Heart 2005;91:427-36). While performing invasive catheterizations for patients who end up having normal coronary arteries is concerning, what is more ominous are the falsely negative stress tests in symptomatic, higher-risk patients (J Nucl Cardiol 2006;13:S26).
It has been proposed that all patients who have chest pain should be sent to the cath lab. While invasive-testing-for-all might be the most comprehensive strategy, it is also the most costly and puts some patients (who end up being normal) at risk for complications (Heart Dis 2003;5:335-44). In patients with chest pain, what we are looking for with any type of noninvasive testing are the answers to three questions:
- Is there severe enough coronary disease to warrant further (i.e., invasive) evaluation and treatment?
- Does the patient have any coronary disease at all but need only medical therapy for the long term?
- Are the coronary arteries normal and in need of no further treatment or evaluation for the foreseeable future?
In the noninvasive evaluation of chest pain, cardiac computed tomographic angiography (CCTA) has been shown to be cost effective and have high specificity. Chest pain patients whose CT angiograms reveal no coronary artery disease don’t have cardiac events in the long term (Am J Cardiol 2009;104:498-500).
Computed tomography with fractional flow reserve (FFRCT) enhances anatomic evaluation with noninvasive functional assessment and has been shown to be superior to simple anatomic evaluation alone (Am J Cardiol 2015;116:1469-78). Two trials (PROMISE and SCOT-HEART) demonstrated that FFRCT improves the clarity of angina diagnoses and, as a result, reduces the number of non-essential invasive cardiac catheterizations (N Engl J Med 2015;372:1291-300; Lancet 2015;385:2383-91; J Am Coll Cardiol 2016;67:843-52).
In chest pain management, precision means identifying patients who do not (or do) need cardiac catheterization and optimizing the tests and procedures that are not (or are) performed in the cath lab. Pre-cath imaging can reveal the location, severity and length of coronary stenoses (Proc [Bayl Univ Med Cent] 2010;23:27-8). In-room robotics can be used to confirm lesion length and deploy stents more precisely. These and other technologies could cut costs by lowering the number of stents implanted per patient while reducing risk to patients with shortened procedure times. The ultimate goal of precision treatment is individually created stents or scaffolds tailored to the patient’s own anatomy (Trends Cardiovasc Med online Feb. 23, 2016).
In the near future, chest pain evaluation will be centered on noninvasive anatomic and functional assessment, allowing more decision-making before procedures. Greater use of these noninvasive tests will reduce costs and increase the safety of invasive procedures.