Background. Myocardial perfusion scintigraphy has been used by some investigators for the diagnosis of coronary artery disease (CAD) in patients with mild, moderate, and moderate to severe aortic stenosis, with various results. The aim of this study was to assess the safety and diagnostic accuracy of adenosine stress myocardial perfusion scintigraphy (adenosine single photon emission computed tomography [Ad-SPECT]) for the detection of CAD in patients with significant aortic stenosis.
Methods and Result. The study included 75 patients with significant aortic stenosis (maximal instantaneous aortic valve gradient >80 mm Hg [range, 81-149 mm Hg] and aortic valve area <0.75 cm 2 ). All patients underwent Ad-SPECT after a 6-minute infusion of adenosine (140 g/kg body weight per minute). At the third minute of adenosine infusion, a bolus of 3 mCi thallium 201 was injected, and SPECT acquisition was obtained immediately after completion of adenosine infusion. Coronary angiography was performed in all patients. No major complications during adenosine infusion were observed. All unpleasant symptoms lasted for only a few seconds and did not necessitate cessation of the test. Concerning the angiographically diagnosed CAD, we found that Ad-SPECT showed a sensitivity of 88.6%, a specificity of 72.5%, a positive predictive value of 73.8%, a negative predictive value of 87.8%, and a diagnostic accuracy of 80%.
Conclusions. Ad-SPECT is a moderately accurate method for detecting the presence or absence of CAD in patients with severe aortic stenosis. However, further modification of this method is required before it can supplant cardiac catheterization in the preoperative evaluation of patients with severe aortic stenosis. (J Nucl Cardiol 2004;11:20-5.)
Key Words: Adenosine โข aortic stenosis โข single photon emission computed tomography
Coexisting coronary artery disease (CAD) is observed in approximately 60% of patients with aortic stenosis. [1][2][3] About two thirds of patients with significant aortic stenosis may have angina. 1 Exercise electrocardiography (ECG) is generally discouraged in these patients, as hypotension, syncope, or even sudden cardiac death may be provoked by stress testing. 4,5 Moreover, exercise ECG in patients with severe aortic stenosis is not used for the diagnosis of CAD; rather, it is mostly used for the stratification of asymptomatic patients with severe aortic stenosis. This test may decide which of those patients will be guided to surgical therapy. 5,6 Furthermore, the traditional exercise stress test and thallium 201 exercise scintigraphy have shown low specificity in detecting CAD in patients with aortic stenosis. 6,7 Adenosine pharmacologic stress myocardial perfusion tomographic imaging with Tl-201 by use of single photon emission computed tomography (Ad-SPECT) in patients with moderate to severe aortic stenosis was found to be well tolerated and diagnostically accurate. 8 The aim of this study was to evaluate the safety and diagnostic accuracy of Ad-SPECT imaging in detecting CAD in patients with significant aortic stenosis.
Methods
The study included 75 patients with significant aortic stenosis (51 men and 24 women), with a mean age of 68.8 ฯฎ 10.7 years. All patients were symptomatic. Their symptoms were dyspnea (57 patients), angina (49 patients), and syncope