Detection of coronary artery disease in patients with severe aortic stenosis with noninvasive methods.

Exercise stress ECG testing is not generally recommended in patients with severe aortic stenosis. Analysis of the utility of exercise testing, both with and without the use of myocardial thallium-201 scintigraphy for the diagnosis of coronary artery disease (CAD), yielded low specificity. A noninvasive, safe, and accurate diagnostic modality to ascertain the presence of CAD is not available to date for patients with severe aortic stenosis. The aim of this study was to assess the safety and diagnostic accuracy of adenosine stress echocardiography (A-Stress-Echo) and of adenosine stress myocardial perfusion scintigraphy (A-SPECT), for the detection of CAD in patients with severe aortic stenosis. The study included 50 patients with severe aortic stenosis (maximal instantaneous aortic valve gradient >80 mmHg, range 81 to 144 mmHg, and aortic valve area <0.75 cm2). All patients were submitted to A-Stress-Echo, after a 6-minute infusion of adenosine (140 microg/kg body weight/min), and then (>3 days later) A-SPECT with the same dosage of adenosine as above. Coronary angiography was performed in all patients. No major complications were observed. The unpleasant symptoms were brief and did not necessitate cessation of the test. Both modalities showed the same sensitivity (85% for A-SPECT and 85% for A-Stress-Echo) angiographically diagnosed CAD while A-Stress-Echo yielded much higher specificity (96.7% vs 76.7%). Concordance of the two methods was found in 40 cases and the specificity for those patients was 100%. A-Stress-Echo and A-SPECT, either separately or in combination, constitute excellent and safe noninvasive diagnostic methods in detecting CAD in patients with severe aortic stenosis.

Non-invasive evaluation of coronary reserve. Assessment of coronary reserve in patients with coronary artery disease by transesophageal-Doppler echocardiography.

We assessed coronary flow reserve using transesophageal Doppler echocardiography in patients with coronary artery disease. The study included 33 coronary artery disease patients who were undergoing coronary arteriography. The blood flow velocities of the left anterior descending artery before and after intravenous infusion (0.56 mg/min for 4 min) of dipyridamole were recorded using transesophageal Doppler echocardiography. Fourteen normal healthy individuals, matched for age, served as a control group. The index of coronary flow reserve, i.e. the ratio of dipyridamole to baseline maximum diastolic velocity, was calculated. Maximal coronary flow reserve in coronary artery disease patients was significantly lower than in the control group (1.4+/-0.2 vs. 2.8+/-0.3, P<0.001). The coronary artery disease patients were classified into three groups: Group A included 10 patients with <50% left anterior descending artery stenosis; Group B included seven patients with 50-69% left anterior descending artery stenosis; 16 patients with >70% left anterior descending artery stenosis constituted Group C. The maximum coronary flow reserve was significantly different for A vs. B and A vs. C. (A, 1.77+/-0.18; B, 1.51+/-0.1; C, 1.28+/-0.24). A strong and significant correlation was found between the maximum coronary flow reserve and the degree of proximal left anterior descending artery stenosis (r=0.78, P<0.001). Coronary artery disease patients without left anterior descending artery stenosis on the arteriogram exhibited lower maximum coronary flow reserve compared to the control subjects (1.78+/-0.19 vs. 2.8+/-0.3, P=0.000).