Accuracy and long-term prognostic value of pacing stress echocardiography compared with dipyridamole tl201 emission computed tomography in patients with a permanent pacemaker and known or suspected coronary artery disease.

OBJECTIVES: Myocardial ischemia is difficult to assess by noninvasive methods in patients with a permanent pacemaker. Pacing stress echocardiography (PASE) has been used successfully in the detection of coronary artery disease (CAD). However, there are no data comparing PASE and other methods. METHODS: We compared agreement and accuracy of PASE and radionuclide tomography (SPECT) in detecting CAD in 58 patients, mean age 75 +/- 7 years, with a permanent pacemaker and known or suspected CAD. Thirty-nine patients underwent coronary angiography. The prognostic value of these tests was determined by prediction of cardiac events and cardiac death. RESULTS: PASE and SPECT were positive in 39 and 43 patients, respectively. The agreement between the tests was 75%; kappa value 0.64. The sensitivity was 87 and 96% and the specificity 78 and 57%, respectively. With median follow-up of 51 months, there were 24 cardiac events and 8 cardiac deaths. Multivariable analysis determined that positive PASE was the only independent predictive factor associated with cardiac events and cardiac death. CONCLUSIONS: PASE is a feasible and effective method for detection of significant CAD in patients with permanent-pacemaker and allows effective risk stratification. PASE merits further study in larger prospective comparative studies.

Additive value of low-dose dobutamine to technetium-99m sestamibi-gated single-photon emission computed tomography for prediction of wall motion improvement in patients undergoing coronary artery bypass graft.

BACKGROUND: The two most useful methods for myocardial viability assessment are perfusion imaging and dobutamine echocardiography. HYPOTHESIS: The present study investigated the additive value of a new method, dobutamine technetium 99m (99mTc)-sestamibi-gated single-photon emission computed tomography (SPECT), which combines these two modalities, to the prediction of wall motion improvement after revascularization. METHODS: Fifty-five consecutive patients with ischemic cardiomyopathy, who were referred for viability evaluation, underwent resting and dobutamine (dose, 5-10 microkg/kg/min) gated SPECT with 99mTc-sestamibi. Of these patients, 36 underwent coronary artery bypass graft (CABG) within 1 month of the study and 32 had repeat resting gated SPECT within 1 year. Global and regional wall motion, wall thickness, and perfusion were simultaneously analyzed at rest and after dobutamine using the 20-segment model; the sestamibi uptake and wall motion response to dobutamine of each segment were rated quantitatively. Based on these findings, the segments were categorized as normal, viable, or nonviable. The predictive values for wall motion improvement were assessed by perfusion, using cutoffs of 50 and 60% of sestamibi uptake, and thereafter by the addition of dobutamine response in the segments that were rated nonviable. RESULTS: Of the 1,080 myocardial segments studied, 906 (84%) had abnormal wall motion and were analyzed for viability. Concordance between perfusion and wall motion response to dobutamine was 60% with the 50% cutoff of sestamibi uptake, and increased to 65% with the 60% sestamibi cutoff (p < 0.04). The respective predictive values of wall motion improvement using the 50 and 60% cutoff points were as follows: sensitivity 93 and 70%, respectively, (p < 0.01); specificity 59 and 86% (p < 0.001), respectively; accuracy 77% for both. The addition of the wall motion response to dobutamine to the assessment of the nonviable segments by perfusion (60% cutoff) increased the sensitivity from 70 to 85% (p = 0.001) and the negative predictive value from 70 to 81% (p = 0.009); the positive predictive value remained high (86 vs. 82%). No additive value of wall motion response to dobutamine was demonstrated for nonviable segments by perfusion with a 50% cutoff. CONCLUSION: Dobutamine sestamibi-gated SPECT is a feasible method for the analysis of myocardial perfusion, function, and contractile reserve of individual myocardial segments in patients with ischemic cardiomyopathy. Viability assessment based on a threshold of 60% uptake of sestamibi, with the addition of the wall motion response to dobutamine in the nonviable segments, seems to yield better predictive values for wall motion improvement after CABG.

Improvement in mitral regurgitation after aortic valve replacement.

BACKGROUND: Concomitant mitral valve regurgitation is often present in patients with aortic stenosis. The additional MV replacement is associated with high operative risk. Previous studies have shown an amelioration of MV regurgitation after aortic valve replacement but most of the patient groups were heterogenous. OBJECTIVES: To determine whether AV replacement for aortic stenosis has any effect on MV regurgitation. METHODS: We reviewed two-dimensional echocardiography and color flow Doppler assessment of both aortic stenosis and MV regurgitation severity in 30 patients. Patients with previous MV surgery, organic MV disease, occlusive carotid artery disease, ejection fraction < 50%, and coexisting significant AV regurgitation were excluded. Preoperatively, MV regurgitation was mild in 23 patients (77%) and moderate in 7 (23%); in no patient was the condition severe. All patients had severe atrial stenosis (peak average aortic gradient 86 +/- 22 mmHg in the mild MV regurgitation group and 83 +/- 26 mmHg in the moderate group). The patients were divided into two groups according to the severity of MV regurgitation (associated mild, and moderate). Group 2, with moderate MV regurgitation, was the most problematic in terms of decision making for concomitant MV surgery. Therefore, additional assessment of several parameters was required. RESULTS: There was a significant decrease in MV regurgitation area (7.6 +/- 1.9 vs. 3.0 +/- 1.2 cm2, P < or = 0.012) and percent (28 +/- 5% vs. 12 +/- 6%, P < or = 0.001) between pre- and postoperative evaluation. Thus, the severity of the condition in all patients with moderate MV regurgitation decreased after AV replacement; in the mild group it remained unchanged in 53% or improved in 47%. There was no association between the preoperative gradient on the aortic valve and the degree of MV regurgitation. CONCLUSIONS: In our population of patients with severe atrial stenosis there were no patients with coexisting severe MV regurgitation. The decision to repair or replace a severely leaking mitral valve is an easy one, as in mild MV regurgitation. The clinical problem often presents in patients with severe aortic stenosis and moderate MV regurgitation. We believe that additional MV surgery is not necessary, at least in patients with preserved left ventricular function and without organic MV disease.