Biomedical subjects

R S Khattar

Publications and source records attributed to R S Khattar.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Comparison of arbutamine stress 99mTc-labeled sestamibi single-photon emission computed tomographic imaging and echocardiography for detection of the extent and severity of coronary artery disease and inducible ischemia.

BACKGROUND: Arbutamine is a new synthetic catecholamine developed specifically for pharmacologic stress testing. METHODS AND RESULTS: We investigated 39 patients undergoing coronary arteriography to compare arbutamine stress (99m)Tc-labeled sestamibi single-photon emission computed tomographic imaging and echocardiography for detection of the extent and severity of coronary artery disease and inducible ischemia. Rest and stress studies were analyzed blindly according to a 12-segment left ventricular model for both techniques. Each segment was graded according to severity of wall thickening abnormality and perfusion defect (1 = normal to 4 = severe). Total perfusion defect and wall thickening scores were calculated at peak stress and the difference in scores between stress and rest (delta perfusion defect; delta wall thickening) were used as indexes of inducible ischemia. Twenty-one patients had multivessel disease, nine had single-vessel disease, and nine had normal coronary arteries. Diagnostic accuracies for the detection of coronary artery disease for single-photon emission computed tomographic imaging and echocardiography were 95% and 92%, respectively. Extent and severity of coronary artery disease indicated by a peak stress perfusion defect score of 26 +/- 6.4 and wall thickening score of 25.1 +/- 8.4 were similar, and there was no significant difference in the delta perfusion defect and delta wall thickening scores of 8.7 +/- 5.5 and 10.4 +/- 7.1, respectively. Segmental concordance rates for the detection of coronary artery disease and inducible ischemia were 74% (K = 0.47; confidence interval 0.39 to 0.55) and 74% (kappa = 0.42; confidence interval 0.34 to 0.51), respectively. Regional concordance for coronary artery disease was 84% (kappa = 0.68; confidence interval 0.51 to 0.84). Where discordance was present, there was a greater prevalence of perfusion abnormality compared with wall thickening abnormality. CONCLUSION: Arbutamine stress single-photon emission computed tomographic imaging and echocardiography provide largely equivalent and accurate pathophysiologic information for the evaluation of coronary artery disease and inducible ischemia.

Cardiotonic Agents↗

PubMedDate not supplied

Improved diagnostic accuracy of planar imaging with technetium 99m-labeled tetrofosmin compared with thallium-201 for the detection of coronary artery disease.

BACKGROUND: Receiver operating characteristic (ROC) curve analysis provides detailed information about the performance of a diagnostic test. METHODS AND RESULTS: As part of a multicenter phase III trial, 160 patients with known or suspected coronary artery disease underwent planar stress-rest 99mTc-labeled tetrofosmin and stress-redistribution 201Tl imaging within 14 days of each other, to compare the diagnostic accuracy of these imaging modalities by ROC curve analysis. Coronary arteriography was used as the reference standard and greater than 70% stenosis was considered significant. ROC curve analysis showed improved detection of coronary artery disease with 99mTc-labeled tetrofosmin compared with 201Tl, with ROC curve areas of 0.765 versus 0.644, respectively (p = 0.02). 99mTc-labeled tetrofosmin also better identified single-vessel disease in those without previous myocardial infarction (ROC curve areas of 0.684 vs 0.510 for 99mTc-labeled tetrofosmin and 201Tl, respectively; p = 0.04) and enhanced the detection of multivessel disease in those with previous myocardial infarction (ROC curve areas of 0.764 vs 0.638, respectively; p = 0.02). CONCLUSIONS: Detailed assessment of diagnostic performance by ROC curve analysis shows that, for planar imaging, 99mTc-labeled tetrofosmin enhances the detection of coronary artery disease compared with 201Tl.

Adult↗

PubMedDate not supplied

Prognostic value of direct, continuous ambulatory blood pressure monitoring in essential hypertension.

This study assessed the prognostic value of ambulatory vs. clinic blood pressure measurement in 688 hypertensives who had undergone pretreatment 24-hour intra-arterial ambulatory blood pressure monitoring. A total of 157 first events were recorded over a follow-up period of 9.2A+/-4.4 years. Ambulatory systolic or diastolic blood pressure parameters (whether 24-hour mean, daytime mean, or nighttime mean) or ambulatory pulse pressure provided independent prognostic information in conjunction with clinical variables. The most predictive models contained the ambulatory systolic blood pressure parameters. Age, male gender, South Asian origin, diabetes mellitus, and previous cardiovascular disease were additional independent predictors of events. In a subgroup of 295 uncomplicated patients, 24-hour ambulatory pulse pressure was an independent predictor of left ventricular mass index and maximal carotid intima-media thickness. Baseline clinic blood pressure parameters did not provide independent information for the prediction of events or target organ damage. Therefore, in this study, ambulatory blood pressure proved to be superior to clinic measurement for cardiovascular risk stratification. However, the routine use of ambulatory blood pressure monitoring is not currently recommended, mainly because of a lack of outcome trials based on the treatment of ambulatory blood pressure levels. (c)2001 by Le Jacq Communications, Inc.

Adult↗