Relationship between exercise echocardiography and perfusion single-photon emission computed tomography in patients with single-vessel coronary artery disease

Abstract

The aim of this study was to assess the relative value of exercise echocardiography and perfusion single-photon emission computed tomography (SPECT) in identifying the presence and severity of coronary artery stenosis. Accordingly, 44 consecutive patients with stenosis in one vessel performed simultaneous postexercise echocardiography and perfusion SPECT (with either thallium-201 [ n = 19] or 99m-Tc-methoxyisobutyl isonitrile [ n = 25]) in conjunction with symptom-limited bicycle exercise testing. Positive test results were based on the presence of new or worsened exercise-induced wall motion abnormalities and transient perfusion defects, respectively. Moreover, an “ischemic” score index was derived for semiquantitative assessment of both echocardiography (with a 14-segment model of left ventricular wall on a 4-point scale) and SPECT (47-segment model on a 5-point scale). All patients underwent correlative coronary arteriography, assessed by digital caliper. Significant coronary artery disease (diameter stenosis ≥ 50%) was present in 30 patients. There was a good overall concordance between the two tests in terms of result (79%); compared with patients with positive results of both tests, in the seven patients with positive SPECT and negative echocardiography the time of recording echocardiographic images was longer ( p = 0.05). When analyzing patients according to the percent diameter stenosis (>70%, 50% to 70%, and <50%) for both echocardiography and SPECT, the prevalence of an ischemic response was directly related to the severity of the coronary stenosis ( p < 0.001); moreover, a negative test result was highly predictive of a diameter coronary stenosis less than 70%. A fair correlation was found between percent diameter stenosis and both ischemic wall motion and perfusion score indexes ( r = 0.62, p < 0.001; r = 0.51, p < 0.001, respectively). It is concluded that in patients with single-vessel disease (1) there is a high concordance between exercise echocardiography and SPECT in terms of an ischemic response, and (2) with both methods the probability of an ischemic response is related to the severity of coronary stenosis.