Pharmacologic cardiac stress SPECT (PS-SPECT) is recommended for non-invasive evaluation of ischemic heart disease (IHD) in patients unable to exercise. With the development of new non-invasive techniques and the wide availability and reduced complications of invasive coronary angiography, it's place in clinical diagnosis has changed.
Define clinical characteristics of patients currently referred for PS-SPECT as well as results and derived management.
Retrospective study of patients referred for PS-SPECT from 2010 to 2016.
There were 1.319 PS-SPECT studies performed during the study period. Most of the patients were women (56%) with a median age of 74±10 years and high prevalence of cardiovascular risk factors including diabetes (51%), hypertension (86%), hypercholesterolemia (64.5%) and peripheral artery disease or stroke (45.5%). Almost half of the patients had chronic IHD.
Dipyridamole was the most frequently used agent for stress, combined or not with low intensity exercise (4% and 88.5%). Main reason for the test was chest pain or acute coronary syndrome (58%), followed by study of dyspnoea or heart failure (10%) and abnormal findings on ECG or echocardiography (10%). There were no serious adverse events after the test, being hypotension the most common complication (21.6%). Although ischemia was diagnosed in the PS-SPECT in 41% of patients, invasive angiography was performed in only 15% of the patients and revascularization in 6%, mostly percutaneously. Mortality was high (24.5% of patients in a mean follow-up of 36 months) most frequently from non cardiac causes (51%).
PS-SPECT is currently reserved to older and sicker patients. Although a relatively high percentage of studies show ischemia, only a few patients are referred for invasive coronary angiography, showing that the result of the test does not necessarily change clinical decision.
Further analysis of the results should help us to identify those patients who would probably not beneficiate from a test with significant radiation exposure and high cost.