Editor's Note: Based on To SPECT or Not to SPECT: Can Temporal Trends at a Single Center Inform Us?
A 55-year-old white man with a history of hypercholesterolemia on statin therapy with no personal history of diabetes or hypertension presents to cardiology clinic for evaluation for chest pain. Pain is described as a sharp pain on the right side of his chest. There is no radiation of the pain or associated symptoms of nausea, diaphoresis, or shortness of breath. Symptoms occur with and without exertion. He reports no difficulty climbing 1 flight of stairs in his home. He denies symptoms of orthopnea, paroxysmal nocturnal dyspnea, pedal edema, pre-syncope, syncope, or palpitations.
On examination, the patient is a well-appearing man with a blood pressure of 130/70 and a heart rate of 82 beats per minute. His cardiac examination is unremarkable and his lungs are clear. His most recent fasting lipid panel showed total cholesterol of 158mg/dL, LDL of 95mg/dL, HDL of 40mg/dL and TG of 115mg/dL.
His electrocardiogram is shown below:
Figure 1
What is the next step for evaluation of this symptomatic patient?
Show Answer
The correct answer is: A. Refer for exercise-stress testing with MPI.
Option A: Refer for exercise-stress testing with MPI
In the symptomatic patient, the AUC for SPECT-MPI suggest stratifying patients based on their pre-test probability for CAD to determine appropriateness for stress testing with perfusion imaging. Given his age and gender, he is characterized as intermediate probability for CAD despite the description of non-anginal chest pain symptoms.1 He has a normal baseline electrocardiogram with good functional status. Therefore, he qualifies for an "appropriate" exercise stress test with MPI for evaluation of inducible ischemia.
Option B: Refer for Coronary CT Angiography (CCTA)
There is emerging evidence for the use of alternate non-invasive modalities such as CCTA for the acute evaluation of patients with chest pain; however, data are not yet conclusive. The ROMICAT-II Investigators demonstrated that the use of Coronary CT Angiography as part of the evaluation strategy for chest pain in the Emergency Department was as effective as standard evaluation.2 The CT-STAT investigators reported that the use of CCTA compared to stress-MPI was more cost efficient and expedited patient throughput.3 It is important to note that chest pain accounts for greater than eight million visits to the Emergency Department and contributes greater than $12 billion annually to total healthcare costs. Therefore improved strategies for triage and evaluation of chest pain are needed, especially in the low to intermediate risk patient. However, there remains a need for further prospective randomized clinical trial data to demonstrate effectiveness of CCTA prior to widespread acceptance of this new modality.
Option C: Further laboratory testing with hsCRP
Risk stratification with biomarkers can play a pivotal role in the asymptomatic patient with intermediate risk classification for development of heart disease. However, hsCRP does not have a role in the evaluation of symptomatic patients.4
Option D: Proceed directly to coronary angiography
Diagnostic testing with coronary angiography should be considered in patients who have a high pre-test probability for CAD. This should not be pursued as the initial strategy in low- to intermediate-risk patients given the invasive nature of the procedure and its possible complications. It is not warranted here in the patient presenting with non-anginal type chest pain who is classified as having an "intermediate" probability of CAD.
The patient is subsequently referred for treadmill exercise stress testing with SPECT-MPI. He exercises for 15 minutes (Bruce protocol) without symptoms or electrocardiographic changes suggestive of ischemia. This raises the question of whether he still requires perfusion imaging.
As suggested by the study by Bourque and colleagues,5 the addition of SPECT-MPI in the intermediate risk patient who is able to exercise for >10 METS may not offer incremental prognostic or diagnostic benefit, questioning the need to pursue imaging in this scenario. We propose that in a new cost-efficient paradigm, the decision to triage the need for SPECT-MPI in the intermediate-risk patient occur in real-time based on exercise capacity. In this population, a low prevalence limits the utility of this test and may result in adverse consequences related to over-utilization, such as cost, radiation, and lack of reliability of results. Such an approach would require systems changes (such as test ordering and laboratory protocols), but may be what is needed to do the right thing for patients in our current cost-conscious environment.
References
Gibbons RJ, Abrams J, Chatterjee K et al. ACC/AHA 2002 guideline update for the management of patients with chronic stable angina—summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Chronic Stable Angina). Circulation 2003;107:149-58.
Hoffmann U, Truong QA, Schoenfeld DA et al. Coronary CT angiography versus standard evaluation in acute chest pain. The New England Journal of Medicine 2012;367:299-308.
Goldstein JA, Chinnaiyan KM, Abidov A et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. Journal of the American College of Cardiology 2011;58:1414-22.
Mohlenkamp S, Lehmann N, Moebus S et al. Quantification of coronary atherosclerosis and inflammation to predict coronary events and all-cause mortality. Journal of the American College of Cardiology 2011;57:1455-64.
Bourque JM, Charlton GT, Holland BH, Belyea CM, Watson DD, Beller GA. Prognosis in patients achieving >/=10 METS on exercise stress testing: was SPECT imaging useful? Journal of Nuclear Cardiology 2011;18:230-7.
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