A healthy 57 year old male presented to the ER with history of sudden sub-sternal chest pain, with radiation to both the upper extremities, 10/10 in intensity at its worst and associated with shortness of breath. The patient had history of similar episodes of chest pain over the last several months which had increased in intensity in the last few weeks. His daily exercise routine was being impeded by the worsening chest pain which usually started after 2-3 minutes of exertion and would go away on resting. He also had a treadmill stress test done 6 months ago which was negative for ischemic heart disease. The patient had no history of any cardiac issues, in fact, any medical problems. He didn’t smoke but used to drink alcohol on daily basis. His workup revealed new T wave inversions in anterolateral leads and raised cardiac markers. He underwent a coronary angiography which showed severe 3 vessel disease, and he eventually underwent an emergent CABG procedure.
Exercise stress testing has traditionally served as a noninvasive tool in the diagnosis of coronary artery disease. It complements the medical history and physical examination, and it remains the second most commonly performed cardiologic procedure next to the routine ECG. Diagnostic stress testing is most valuable in patients with intermediate pre-test probability, because the test result has the largest potential effect on diagnostic outcome. Our patient was initially considered intermediate risk and during the treadmill stress test, our patient was able to endure a workload equivalent to 10.8 METS, without any chest pain or ischemic ST-segment depression. Therefore, his stress test was considered a low-risk test, predictive of an annual mortality rate of less than 1%. Nevertheless, he presented within next 6 months with NSTEMI due to severe 3 vessel disease.
Exercise stress testing has a low sensitivity and specificity (67% and 72%, respectively). Coronary artery disease is a dynamic disease and a negative stress test doesn’t mean much. Thus, other noninvasive modalities, including coronary CT-angiography and whole-heart coronary magnetic resonance angiography, which have higher sensitivity and specificity in detecting coronary artery disease are gaining popularity. These noninvasive imaging modalities are able to detect the location of the coronary atherosclerotic plaque and to estimate the degree of lumen reduction.