- Email: [email protected]
SAI-14
ity of CAC area and/or score. Use of the larger FOV (35 cm) ensures that the complete heart is imaged, and does not alter the score results.
SAI-13 Does 99mTc-Sestamibi Single-Photon Emission Computed Tomography Stress Testing Detect Coronary Artery Disease in Patients Being Evaluated for Chest Pain? J. Michel, S. Royal, and G. Wagner Duke University Medical Center, Durham, North Carolina, USA 99m Tc-sestamibi single-photon emission computed tomography (SPECT) stress testing has high sensitivity, specificity, and accuracy (⬎90%) for detecting coronary artery disease (CAD) in controlled study populations. However, its ability to detect CAD in a population being evaluated for chest pain is less clearly established. We studied 283 consecutive patients (60% women, 40% men) from 5 counties in North Carolina referred for cardiac catheterization. Patients had chest pain but no history of CAD. 99mTc-sestamibi SPECT stress testing was performed before catheterization. Stress-induced 99mTc-sestamibi SPECT abnormalities were identified in 62% of patients. Catheterization identified CAD (lesions ⱖ75% in a major vessel or large branch) in 32% of patients with stress-induced SPECT abnormalities and 23% of patients without stress-induced abnormalities. Calculated sensitivity, specificity, and predictive accuracy for CAD detection were 69%, 42%, and 50%, respectively. To account for referral bias, we evaluated the local normalcy rate of 99mTc-sestamibi SPECT stress testing and estimated the number of patients with negative studies not going on to catheterization. Assuming no false negatives in this group, sensitivity, specificity, and accuracy are, respectively, 69%, 80%, and 79%. Assuming 23% false negatives (percent observed at catheterization), sensitivity, specificity, and accuracy are 33%, 77%, and 60%. Thus, true sensitivity appears to fall between 33% and 69%. These data indicate that uncertainty exists regarding the ability of 99mTc-sestamibi SPECT stress testing to accurately detect CAD in a population being evaluated for chest pain.
SAI-14 Does Electron-Beam Computed Tomography Add Incremental Value to Pretest Likelihood in Predicting Abnormal Myocardial Perfusion SinglePhoton Emission Computed Tomography in Asymptomatic Patients? R. S. Miranda, E. F. Schisterman, D. S. Berman, H. C. Lewin, S. W. Hayes, J. D. Friedman, I. Cohen, A. M. Gallagher, and G. Germano Cedars-Sinai Medical Center, Los Angeles, California, USA Coronary calcium score (CCS) by electron-beam computed tomography (EBCT) has been shown to have important predictive value for future coronary events. However, its incremental ability to predict the likelihood of abnormal nuclear scans over standard clinical assessment is unclear. 80E THE AMERICAN JOURNAL OF CARDIOLOGY姞
We studied 355 consecutive asymptomatic patients (pts) (male, 80.3 ⫾ 2.1%; age, 58.9 ⫾ 0.53) who had both EBCT and myocardial perfusion single-photon emission computed tomography (MPS) imaging at our institution. EBCT and MPS were performed within 180 days, with a mean of 30.0 ⫾ 2.1 days between tests. CCS was calculated from EBCT by the Agatston scoring technique. Rest 201Th with stress (87.3% exercise, 12.7% pharmacologic)-gated 99mTc-sestamibi MPS images were interpreted by semiquantitative visual analysis and categorized for overall interpretation as normal or abnormal. Pretest likelihood for coronary artery disease (CAD) was used as a comprehensive clinical index and was calculated based on age, sex, and other cardiac risk factors. Patients were divided into 2 groups: normal MPS pts (n ⫽ 329) and abnormal MPS pts (n ⫽ 26). Using logistic regression analysis, abnormal MPS pts had significantly higher pretest likelihood (p ⬍0.05) and significantly higher CCS (p ⬍0.001). Incremental value of CCS over pretest likelihood in predicting abnormal MPS was significant (2 ⫽ 12.04, p ⬍0.001). The area-under-the receiver operating characteristic curve was 0.650 for pretest likelihood alone and 0.771 for pretest likelihood and CCS combined (p ⬍0.01). We conclude that EBCT provides incremental information over pretest likelihood of CAD in predicting likelihood of abnormal MPS, and may thus prove a better discriminator of the necessity for further testing than standard clinical assessment.
SAI-15 Coronary Thermosensor Basket Catheter with Thermographic Imaging Software for Thermal Detection of Vulnerable Atherosclerotic Plaques M. Naghavi, K. Gul, T. O’Brien, S. Siadaty, M. Madjid, R. M. Mohammadi, T. Tewatia, J. T. Willerson, and W. Casscells University of Texas-Houston, Houston, Texas, USA (MN, KG, SS, MM, RMM, TT, JTW, WC); Texas Heart Institute, Houston, Texas, USA (MN, JTW, WC); Temperature Specialist Inc., St. Francis, Minnesota, USA (TO) Vulnerable atherosclerotic plaques are known to be inflamed and have higher temperature (T) than the adjacent areas. We have previously reported the first prototype of our intravascular Thermosensor basket catheter (BC). Here we report the next generation prototype to be used in clinical studies. The new BC system (see figure) consists of: (1) a 4-Fr catheter with an expandable and externally controllable basket with 9 built-in thermosensors, (2) a computer board with special digital transistors for high-speed sampling, (3) a personal computer equipped with the board, (4) a custom software for real-time data acquisition, tracking, and thermographic imaging, and (5) a circulating microbath for automatic thermal calibration. The expandable basket at the end of catheter is made of 4 to 8 highly flexible hollow wires (inside diameter, 0.003”; outside diameter, 0.05”) with 0.001” built-in thermocouples. Each wire has 2 sensors located at the maximum curve, 0.5 mm apart, allowing monitoring of T between and within plaques. The catheter also has a central wire with a thermal sensor to monitor the blood T simultaneously. The real-time data acquisition software supports digital transmitters for each channel with a thermal resolution of 0.0025°C and a sampling rate of 20 readings per second. It can also display the circumferential and longitudinal thermal map of the vessel wall.
VOL. 88 (2A)
JULY 19, 2001
SAI-13 Does 99mTc-Sestamibi Single-Photon Emission Computed Tomography Stress Testing Detect Coronary Artery Disease in Patients Being Evaluated for Chest Pain? J. Michel, S. Royal, and G. Wagner Duke University Medical Center, Durham, North Carolina, USA 99m Tc-sestamibi single-photon emission computed tomography (SPECT) stress testing has high sensitivity, specificity, and accuracy (⬎90%) for detecting coronary artery disease (CAD) in controlled study populations. However, its ability to detect CAD in a population being evaluated for chest pain is less clearly established. We studied 283 consecutive patients (60% women, 40% men) from 5 counties in North Carolina referred for cardiac catheterization. Patients had chest pain but no history of CAD. 99mTc-sestamibi SPECT stress testing was performed before catheterization. Stress-induced 99mTc-sestamibi SPECT abnormalities were identified in 62% of patients. Catheterization identified CAD (lesions ⱖ75% in a major vessel or large branch) in 32% of patients with stress-induced SPECT abnormalities and 23% of patients without stress-induced abnormalities. Calculated sensitivity, specificity, and predictive accuracy for CAD detection were 69%, 42%, and 50%, respectively. To account for referral bias, we evaluated the local normalcy rate of 99mTc-sestamibi SPECT stress testing and estimated the number of patients with negative studies not going on to catheterization. Assuming no false negatives in this group, sensitivity, specificity, and accuracy are, respectively, 69%, 80%, and 79%. Assuming 23% false negatives (percent observed at catheterization), sensitivity, specificity, and accuracy are 33%, 77%, and 60%. Thus, true sensitivity appears to fall between 33% and 69%. These data indicate that uncertainty exists regarding the ability of 99mTc-sestamibi SPECT stress testing to accurately detect CAD in a population being evaluated for chest pain.
SAI-14 Does Electron-Beam Computed Tomography Add Incremental Value to Pretest Likelihood in Predicting Abnormal Myocardial Perfusion SinglePhoton Emission Computed Tomography in Asymptomatic Patients? R. S. Miranda, E. F. Schisterman, D. S. Berman, H. C. Lewin, S. W. Hayes, J. D. Friedman, I. Cohen, A. M. Gallagher, and G. Germano Cedars-Sinai Medical Center, Los Angeles, California, USA Coronary calcium score (CCS) by electron-beam computed tomography (EBCT) has been shown to have important predictive value for future coronary events. However, its incremental ability to predict the likelihood of abnormal nuclear scans over standard clinical assessment is unclear. 80E THE AMERICAN JOURNAL OF CARDIOLOGY姞
We studied 355 consecutive asymptomatic patients (pts) (male, 80.3 ⫾ 2.1%; age, 58.9 ⫾ 0.53) who had both EBCT and myocardial perfusion single-photon emission computed tomography (MPS) imaging at our institution. EBCT and MPS were performed within 180 days, with a mean of 30.0 ⫾ 2.1 days between tests. CCS was calculated from EBCT by the Agatston scoring technique. Rest 201Th with stress (87.3% exercise, 12.7% pharmacologic)-gated 99mTc-sestamibi MPS images were interpreted by semiquantitative visual analysis and categorized for overall interpretation as normal or abnormal. Pretest likelihood for coronary artery disease (CAD) was used as a comprehensive clinical index and was calculated based on age, sex, and other cardiac risk factors. Patients were divided into 2 groups: normal MPS pts (n ⫽ 329) and abnormal MPS pts (n ⫽ 26). Using logistic regression analysis, abnormal MPS pts had significantly higher pretest likelihood (p ⬍0.05) and significantly higher CCS (p ⬍0.001). Incremental value of CCS over pretest likelihood in predicting abnormal MPS was significant (2 ⫽ 12.04, p ⬍0.001). The area-under-the receiver operating characteristic curve was 0.650 for pretest likelihood alone and 0.771 for pretest likelihood and CCS combined (p ⬍0.01). We conclude that EBCT provides incremental information over pretest likelihood of CAD in predicting likelihood of abnormal MPS, and may thus prove a better discriminator of the necessity for further testing than standard clinical assessment.
SAI-15 Coronary Thermosensor Basket Catheter with Thermographic Imaging Software for Thermal Detection of Vulnerable Atherosclerotic Plaques M. Naghavi, K. Gul, T. O’Brien, S. Siadaty, M. Madjid, R. M. Mohammadi, T. Tewatia, J. T. Willerson, and W. Casscells University of Texas-Houston, Houston, Texas, USA (MN, KG, SS, MM, RMM, TT, JTW, WC); Texas Heart Institute, Houston, Texas, USA (MN, JTW, WC); Temperature Specialist Inc., St. Francis, Minnesota, USA (TO) Vulnerable atherosclerotic plaques are known to be inflamed and have higher temperature (T) than the adjacent areas. We have previously reported the first prototype of our intravascular Thermosensor basket catheter (BC). Here we report the next generation prototype to be used in clinical studies. The new BC system (see figure) consists of: (1) a 4-Fr catheter with an expandable and externally controllable basket with 9 built-in thermosensors, (2) a computer board with special digital transistors for high-speed sampling, (3) a personal computer equipped with the board, (4) a custom software for real-time data acquisition, tracking, and thermographic imaging, and (5) a circulating microbath for automatic thermal calibration. The expandable basket at the end of catheter is made of 4 to 8 highly flexible hollow wires (inside diameter, 0.003”; outside diameter, 0.05”) with 0.001” built-in thermocouples. Each wire has 2 sensors located at the maximum curve, 0.5 mm apart, allowing monitoring of T between and within plaques. The catheter also has a central wire with a thermal sensor to monitor the blood T simultaneously. The real-time data acquisition software supports digital transmitters for each channel with a thermal resolution of 0.0025°C and a sampling rate of 20 readings per second. It can also display the circumferential and longitudinal thermal map of the vessel wall.
VOL. 88 (2A)
JULY 19, 2001