D. Georgiou - Academia.edu (original) (raw)
Papers by D. Georgiou
American journal of cardiac imaging, 1995
A case of previously undiagnosed cervical carcinoma metastatic to the right ventricular cavity an... more A case of previously undiagnosed cervical carcinoma metastatic to the right ventricular cavity and the central and peripheral pulmonary arteries is presented. The usefulness of ultrafast computed tomography in comparison with echocardiography for the evaluation of suspected metastatic diseases to the heart and pulmonary arteries is discussed.
Catheterization and Cardiovascular Diagnosis, 1994
Ultrafast computed tomography (UFCT) has the potential to quantlfy coronary hydroxyapatite (HAP).... more Ultrafast computed tomography (UFCT) has the potential to quantlfy coronary hydroxyapatite (HAP). However, no definitive studies validating this technique are available. We constructed a human chest phantom model with coronary arterles represented by cylindrical holes containing: (1) calcium chloride solutions, (2) a block of HAP Immersed in paraffin (without partial volume effect), and (3) HAP granules embedded in a gelatin matrix (with partial volume effect). We scanned this model to determine the relationship between measured CT number per voxel and density of the calcium per voxel. The relationships between CT number and concentration of calcium chloride was linear (r = 0.992 to 0.999). Using a commercially avallable standard bone mineral phantom, we were able to estimate the concentration of HAP to an accuracy from 94 to 97% when partial volume effects were absent. However, when partial volume effects were present, two methods of estimating HAP produced significant errors (1 to 384%, and 17 to 520h). We conclude that significant partial Voluming errors degrade the accuracy of HAP quantltation and that further evaluation and corrections are needed before such quantitation Is clinically applied.
Journal of the American College of Cardiology, 2001
The high sensitivity of electron beam tomography (EBT) in the detection of coronary artery calciu... more The high sensitivity of electron beam tomography (EBT) in the detection of coronary artery calcium (CAC) and obstructive coronary artery disease prompted us to investigate the association between CAC detection and future cardiac events in patients with acute chest pain syndromes requiring hospitalization. Three studies have documented that EBT is a rapid and efficient screening tool for patients admitted to the emergency department (ED) with chest pain, but there is a paucity of long-term follow-up data on these chest pain patients. We conducted a prospective observational study of 192 patients admitted to the ED of a large tertiary care hospital for chest pain syndromes. Upon admission, patients underwent EBT scanning in addition to the usual care for chest pain syndromes. During the 17-month enrollment period, 221 patients were scanned (54% men with a mean age of 53 +/- 9 years). Average follow-up was 50 +/- 10 months using chart review. Fifty-eight patients had coronary events confirmed by a blinded medical record review. The presence of CAC (a total calcium score >0) and increasing score quartiles were strongly related to the occurrence of hard cardiac events including myocardial infarction and death (p < 0.001) and all cardiovascular events (p < 0.001). Stratification by age- and gender-matching further increased the prognostic ability of EBT (for scores above vs. below the age- and gender-matched CAC scores; odds ratio: 13.1, 95% confidence intervals: 5.62, 35.9). These data support previous reports demonstrating that the presence of CAC in a symptomatic cohort is a strong predictor of future cardiac events. This study supports the use of EBT in a symptomatic cohort with prompt discharge of those patients with negative scans. Furthermore, the absence of CAC is associated with a very low risk of future cardiac risk events in this population over the subsequent seven years (annual event rate <1%).
Journal of Cardiopulmonary Rehabilitation, 1996
Objectives. The present study was designed to evaluate whether a specific program of low intensit... more Objectives. The present study was designed to evaluate whether a specific program of low intensity exercise training may be sufficient to improve the exercise tolerance of patients with chronic heart failure.
Journal of Cardiopulmonary Rehabilitation, 1998
This study sought to investigate whether the identification of hibernating myocardium by low dose... more This study sought to investigate whether the identification of hibernating myocardium by low dose dobutamine stress echocardiography (LDSE) may predict an improvement in functional capacity after moderate exercise training in patients with ischemic cardiomyopathy. Another objective was to assess whether exercise training may affect the outcome. There is evidence that exercise training improves left ventricular (LV) function as well as functional capacity in patients with a previous myocardial infarction and LV dysfunction. We hypothesized that the magnitude of these improvements might be related to the extent of hibernating myocardium. We studied 71 consecutive patients 56+/-9 years old (mean +/- SD) with chronic heart failure secondary to ischemic cardiomyopathy (LV ejection fraction [LVEF] <40%). All patients were in sinus rhythm and were clinically stable during the previous 3 months. Patients were randomized into two matched groups. Group T (n = 36) underwent exercise training at 60% of peak oxygen uptake (Vo2) three times a week for 10 weeks. Group C (n = 35) did not exercise. At study entry and end, all patients underwent an exercise test with gas exchange analysis and LDSE (5 to 20 microg/kg body weight per min). At baseline, a positive contractile response (CS+) to LDSE was observed in 317 of 576 segments in group T and 291 of 560 segments in group C. After 10 weeks, peak Vo2 and peak work rate increased only in trained patients (peak Vo2: from 16.2+/-3 to 20.8+/-4 ml/kg per min; work capacity: from 108+/-20 to 131+/-25 W, p < 0.001 vs. group C for both). The presence of CS+ at baseline was associated with a sensitivity of 70% and a specificity of 77% for predicting an increase in the functional capacity after exercise training. Positive and negative predictive values of LDSE were 84% and 59%, respectively. Independent predictors of cardiac events were a pre-to-posttraining difference in LVEF at peak dobutamine infusion and the presence of a viable response at baseline (p = 0.004 and 0.008, respectively). The log-rank test demonstrated that trained patients had a significantly lower probability of cardiac events during follow-up than sedentary control patients (p < 0.001). The presence of hibernating myocardium as assessed by LDSE predicts the magnitude of improvement in functional capacity after moderate exercise training in patients with chronic heart failure. A significant increase in functional capacity after exercise training is associated with a lower incidence of cardiac events during follow-up.
Investigative Radiology, 1995
Validation of right ventricular mass quantitation by electron beam computed tomography in humans ... more Validation of right ventricular mass quantitation by electron beam computed tomography in humans has not been performed. The ability of electron beam computed tomography to accurately determine the septal component of the right ventricle also has not been determined. This article addresses both issues. Twenty human adult hearts obtained at autopsy were scanned by electron beam computed tomography in a short-axis projection. Planimetry of the right ventricular free wall and septal components of each slice was performed and summed to determine right ventricular mass. These measurements were compared against comparable measurements obtained by autopsy weights of the hearts. Right ventricular free wall weights by electron beam computed tomography (53.9 +/- 18.4 g) correlated well (slope = .92, r = .92, standard error of the estimate = 7.4 g, P &amp;lt; .001) with autopsy weights (55.8 +/- 18.4 g). Right ventricular septal weights by electron beam computed tomography (6.1 +/- 2.3 g) correlated poorly (slope = .04, r = .11, standard error of the estimate = 2.4 g, P = .65) with autopsy weights (13.9 +/- 6.3 g). Electron beam computed tomography quantitation of right ventricular mass is accurate in humans if only the free wall and not the septal component is utilized.
Diabetic Medicine, 2005
ABSTRACT
Circulation, 1996
Ultrafast computed tomography (CT), by acquiring images of the proximal coronary arteries, detect... more Ultrafast computed tomography (CT), by acquiring images of the proximal coronary arteries, detects coronary calcifications and has been demonstrated to be highly sensitive for the detection of coronary artery disease in many small studies. The aim of this study was to determine the relationship between ultrafast CT scanning and coronary angiography in a large number of symptomatic patients. The study population consisted of 710 patients from six participating centers. A multivariate logistic regression model was used to evaluate the individual contributions of age, number of calcified vessels, and the calcium score for the probability of angiographically significant disease. Of the 710 patients enrolled, 427 patients had significant angiographic disease, and coronary calcification was detected in 404, yielding a sensitivity of 95%. Of the 23 patients without calcifications, 19 (83%) had single-vessel disease at angiography. Of the 283 patients without angiographically significant disease, 124 had negative ultrafast CT coronary studies, for a specificity of 44%. An increasing number of vessels with calcification present on ultrafast CT was found to increase specificity for the presence of obstructive coronary artery disease in at least one vessel (P &amp;amp;amp;lt; .0001). As the log of the calcium score increases, the probability of multivessel obstructive disease increases (P &amp;amp;amp;lt; .0001). Ultrafast CT scanning is an noninvasive, non-exercise-dependent test with an excellent sensitivity for the detection of coronary artery disease. The presence of calcifications in multiple vessels and in younger populations correlates with higher specificities for obstructive disease, making ultrafast CT coronary scanning a very useful diagnostic test.
CHEST Journal, 1994
The presence of a perivalvular abscess is associated with an increased risk of morbidity and mort... more The presence of a perivalvular abscess is associated with an increased risk of morbidity and mortality with valve replacement and can require extensive debridement and reconstructive procedures. An accurate noninvasive method for preoperative diagnosis may hasten operation and aid in preoperative and surgical management. Two cases are presented in which ultrafast computed tomography accurately identified perivalvular abscesses not detected on two-dimensional transthoracic echocardiography and guided operative intervention.
The American Journal of Cardiology, 1998
We compared intracoronary ultrasound (ICUS) and electron-beam computed tomography (EBCT) on a cor... more We compared intracoronary ultrasound (ICUS) and electron-beam computed tomography (EBCT) on a coronary segmental basis in 40 consecutive patients with acute coronary syndromes and no or minimal to moderate angiographic disease (53 ؎ 10 years; 34 men, 6 women). ICUS was used to define plaques, and EBCT was used to quantify coronary calcium (using a threshold of a CT density >130 Hounsfield units in an area >1.03 mm 2 ). In a site-by-site analysis, coronary segments were defined as normal if both methods were negative, as containing noncalcified plaques if only ICUS was positive, and as containing calcified plaques if both methods were positive. A total of 222 coronary segments were analyzed (5.6 ؎ 1.9 segments per patient). In 36 patients (90%), a total of 95 segments with plaques were identified, whereas in 4 patients (10%), only normal segments were seen. Of the 95 segments with plaques, 61 (64%) were calcified, and 34 (36%) were noncalcified. There was a linear relationship between the num-ber of segments with calcified and with noncalcified plaques (r ؍ 0.86, p <0.0001), but the mean relative frequency of segments with calcified plaques (55 ؎ 38%) was highly variable. Calcium was found in 15 of 16 patients (93%) with 3 or more segments with plaques, while it was found in only 12 of 20 patients (60%) with one or 2 segments with plaques (p ؍ 0.026). Younger age, higher low-density lipoprotein-cholesterol levels, diabetes, and active smoking predicted a higher relative frequency of segments with noncalcified plaques. Thus, in patients with acute coronary syndromes but no angiographically critical stenoses, there is a linear relationship between segments with calcified plaques versus segments with noncalcified plaques. However, while the mean ratio of these segments is close to 1:1, it is highly variable among individual patients.
The American Journal of Cardiology, 1998
This blinded, single center study prospectively compares exercise electron beam computed tomograp... more This blinded, single center study prospectively compares exercise electron beam computed tomography (EBCT) with stress technetium-99m (Tc-99m) sestamibi singlephoton emission computed tomography (SPECT) in 33 patients undergoing coronary angiography for evaluation of chest pain. Patients undergoing routine cardiac catheterization for the diagnosis of chest pain were imaged at rest using EBCT. Patients exercised on a semisupine ergometer, and exercise EBCT was immediately followed by injection of Tc-99m sestamibi for assessment of myocardial ischemia. At peak exercise, Tc-99m SPECT, followed immediately by nonionic contrast material, was injected intravenously to directly compare these 2 imaging techniques. Patients were reimaged with Tc-99m SPECT at rest 24 to 48 hours after stress. Exercise EBCT, which was analyzed using a global ejec-tion fraction measure, had a sensitivity of 81% and a specificity of 76%, compared with angiography. Using the development of a new regional wall motion abnormality as evidence of obstructive coronary artery disease (CAD), EBCT yielded a specificity of 100% and a sensitivity of 88%. Reversible perfusion defects identified by SPECT, as evidence of obstructive CAD, revealed a sensitivity of 75% and a specificity of 71%. The specificity of regional wall motion analysis by EBCT was significantly better than SPECT (p <0.01) in this population. This study demonstrates regional wall motion assessed by EBCT to be as sensitive and more specific than SPECT myocardial perfusion imaging in identifying obstructive CAD as defined by angiography. ᮊ1998 by Excerpta Medica, Inc.
American Heart Journal, 1994
Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiogr... more Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiographic technology can detect coronary calcium before atherosclerosis becomes symptomatic.
The American Journal of Cardiology, 2001
The purpose of this study is to perform a cost-effectiveness analysis of long-term moderate exerc... more The purpose of this study is to perform a cost-effectiveness analysis of long-term moderate exercise training (ET) in patients with stable chronic heart failure. In particular, the study focuses on the survival analysis and cost savings from the reduction in the hospitalization rate in the exercise group. In the past 10 years, ET has been shown to be beneficial for patients with stable class II and III heart failure in many randomized clinical trials. However, the cost-effectiveness of a long-term ET program has not been addressed for outcomes related to morbidity/mortality end points or health care utilization. We examined the cost-effectiveness of a 14-month longterm training in patients with stable chronic heart failure. The estimated increment cost for the training group, 3,227/patient,wascalculatedbysubtractingtheavertedhospitalizationcost,3,227/patient, was calculated by subtracting the averted hospitalization cost, 3,227/patient,wascalculatedbysubtractingtheavertedhospitalizationcost,1,336/patient, from the cost of ET and wage lost due to ET, estimated at 4,563/patient.ForpatientsreceivingET,theestimatedincrementinlifeexpectancywas1.82years/personinatimeperiodof15.5years,comparedwithpatientsinthecontrolgroup.Thecost−effectivenessratioforlong−termETinpatientswithstableheartfailurewasthusdeterminedat4,563/ patient. For patients receiving ET, the estimated increment in life expectancy was 1.82 years/person in a time period of 15.5 years, compared with patients in the control group. The cost-effectiveness ratio for long-term ET in patients with stable heart failure was thus determined at 4,563/patient.ForpatientsreceivingET,theestimatedincrementinlifeexpectancywas1.82years/personinatimeperiodof15.5years,comparedwithpatientsinthecontrolgroup.Thecost−effectivenessratioforlong−termETinpatientswithstableheartfailurewasthusdeterminedat1,773/life-year saved, at a 3% discount rate. Long-term ET in patients with stable chronic heart failure is cost-effective and prolongs survival by an additional 1.82 years at a low cost of $1,773 per/life-year saved.
American journal of cardiac imaging, 1995
A case of previously undiagnosed cervical carcinoma metastatic to the right ventricular cavity an... more A case of previously undiagnosed cervical carcinoma metastatic to the right ventricular cavity and the central and peripheral pulmonary arteries is presented. The usefulness of ultrafast computed tomography in comparison with echocardiography for the evaluation of suspected metastatic diseases to the heart and pulmonary arteries is discussed.
Catheterization and Cardiovascular Diagnosis, 1994
Ultrafast computed tomography (UFCT) has the potential to quantlfy coronary hydroxyapatite (HAP).... more Ultrafast computed tomography (UFCT) has the potential to quantlfy coronary hydroxyapatite (HAP). However, no definitive studies validating this technique are available. We constructed a human chest phantom model with coronary arterles represented by cylindrical holes containing: (1) calcium chloride solutions, (2) a block of HAP Immersed in paraffin (without partial volume effect), and (3) HAP granules embedded in a gelatin matrix (with partial volume effect). We scanned this model to determine the relationship between measured CT number per voxel and density of the calcium per voxel. The relationships between CT number and concentration of calcium chloride was linear (r = 0.992 to 0.999). Using a commercially avallable standard bone mineral phantom, we were able to estimate the concentration of HAP to an accuracy from 94 to 97% when partial volume effects were absent. However, when partial volume effects were present, two methods of estimating HAP produced significant errors (1 to 384%, and 17 to 520h). We conclude that significant partial Voluming errors degrade the accuracy of HAP quantltation and that further evaluation and corrections are needed before such quantitation Is clinically applied.
Journal of the American College of Cardiology, 2001
The high sensitivity of electron beam tomography (EBT) in the detection of coronary artery calciu... more The high sensitivity of electron beam tomography (EBT) in the detection of coronary artery calcium (CAC) and obstructive coronary artery disease prompted us to investigate the association between CAC detection and future cardiac events in patients with acute chest pain syndromes requiring hospitalization. Three studies have documented that EBT is a rapid and efficient screening tool for patients admitted to the emergency department (ED) with chest pain, but there is a paucity of long-term follow-up data on these chest pain patients. We conducted a prospective observational study of 192 patients admitted to the ED of a large tertiary care hospital for chest pain syndromes. Upon admission, patients underwent EBT scanning in addition to the usual care for chest pain syndromes. During the 17-month enrollment period, 221 patients were scanned (54% men with a mean age of 53 +/- 9 years). Average follow-up was 50 +/- 10 months using chart review. Fifty-eight patients had coronary events confirmed by a blinded medical record review. The presence of CAC (a total calcium score &amp;gt;0) and increasing score quartiles were strongly related to the occurrence of hard cardiac events including myocardial infarction and death (p &amp;lt; 0.001) and all cardiovascular events (p &amp;lt; 0.001). Stratification by age- and gender-matching further increased the prognostic ability of EBT (for scores above vs. below the age- and gender-matched CAC scores; odds ratio: 13.1, 95% confidence intervals: 5.62, 35.9). These data support previous reports demonstrating that the presence of CAC in a symptomatic cohort is a strong predictor of future cardiac events. This study supports the use of EBT in a symptomatic cohort with prompt discharge of those patients with negative scans. Furthermore, the absence of CAC is associated with a very low risk of future cardiac risk events in this population over the subsequent seven years (annual event rate &amp;lt;1%).
Journal of Cardiopulmonary Rehabilitation, 1996
Objectives. The present study was designed to evaluate whether a specific program of low intensit... more Objectives. The present study was designed to evaluate whether a specific program of low intensity exercise training may be sufficient to improve the exercise tolerance of patients with chronic heart failure.
Journal of Cardiopulmonary Rehabilitation, 1998
This study sought to investigate whether the identification of hibernating myocardium by low dose... more This study sought to investigate whether the identification of hibernating myocardium by low dose dobutamine stress echocardiography (LDSE) may predict an improvement in functional capacity after moderate exercise training in patients with ischemic cardiomyopathy. Another objective was to assess whether exercise training may affect the outcome. There is evidence that exercise training improves left ventricular (LV) function as well as functional capacity in patients with a previous myocardial infarction and LV dysfunction. We hypothesized that the magnitude of these improvements might be related to the extent of hibernating myocardium. We studied 71 consecutive patients 56+/-9 years old (mean +/- SD) with chronic heart failure secondary to ischemic cardiomyopathy (LV ejection fraction [LVEF] <40%). All patients were in sinus rhythm and were clinically stable during the previous 3 months. Patients were randomized into two matched groups. Group T (n = 36) underwent exercise training at 60% of peak oxygen uptake (Vo2) three times a week for 10 weeks. Group C (n = 35) did not exercise. At study entry and end, all patients underwent an exercise test with gas exchange analysis and LDSE (5 to 20 microg/kg body weight per min). At baseline, a positive contractile response (CS+) to LDSE was observed in 317 of 576 segments in group T and 291 of 560 segments in group C. After 10 weeks, peak Vo2 and peak work rate increased only in trained patients (peak Vo2: from 16.2+/-3 to 20.8+/-4 ml/kg per min; work capacity: from 108+/-20 to 131+/-25 W, p < 0.001 vs. group C for both). The presence of CS+ at baseline was associated with a sensitivity of 70% and a specificity of 77% for predicting an increase in the functional capacity after exercise training. Positive and negative predictive values of LDSE were 84% and 59%, respectively. Independent predictors of cardiac events were a pre-to-posttraining difference in LVEF at peak dobutamine infusion and the presence of a viable response at baseline (p = 0.004 and 0.008, respectively). The log-rank test demonstrated that trained patients had a significantly lower probability of cardiac events during follow-up than sedentary control patients (p < 0.001). The presence of hibernating myocardium as assessed by LDSE predicts the magnitude of improvement in functional capacity after moderate exercise training in patients with chronic heart failure. A significant increase in functional capacity after exercise training is associated with a lower incidence of cardiac events during follow-up.
Investigative Radiology, 1995
Validation of right ventricular mass quantitation by electron beam computed tomography in humans ... more Validation of right ventricular mass quantitation by electron beam computed tomography in humans has not been performed. The ability of electron beam computed tomography to accurately determine the septal component of the right ventricle also has not been determined. This article addresses both issues. Twenty human adult hearts obtained at autopsy were scanned by electron beam computed tomography in a short-axis projection. Planimetry of the right ventricular free wall and septal components of each slice was performed and summed to determine right ventricular mass. These measurements were compared against comparable measurements obtained by autopsy weights of the hearts. Right ventricular free wall weights by electron beam computed tomography (53.9 +/- 18.4 g) correlated well (slope = .92, r = .92, standard error of the estimate = 7.4 g, P &amp;lt; .001) with autopsy weights (55.8 +/- 18.4 g). Right ventricular septal weights by electron beam computed tomography (6.1 +/- 2.3 g) correlated poorly (slope = .04, r = .11, standard error of the estimate = 2.4 g, P = .65) with autopsy weights (13.9 +/- 6.3 g). Electron beam computed tomography quantitation of right ventricular mass is accurate in humans if only the free wall and not the septal component is utilized.
Diabetic Medicine, 2005
ABSTRACT
Circulation, 1996
Ultrafast computed tomography (CT), by acquiring images of the proximal coronary arteries, detect... more Ultrafast computed tomography (CT), by acquiring images of the proximal coronary arteries, detects coronary calcifications and has been demonstrated to be highly sensitive for the detection of coronary artery disease in many small studies. The aim of this study was to determine the relationship between ultrafast CT scanning and coronary angiography in a large number of symptomatic patients. The study population consisted of 710 patients from six participating centers. A multivariate logistic regression model was used to evaluate the individual contributions of age, number of calcified vessels, and the calcium score for the probability of angiographically significant disease. Of the 710 patients enrolled, 427 patients had significant angiographic disease, and coronary calcification was detected in 404, yielding a sensitivity of 95%. Of the 23 patients without calcifications, 19 (83%) had single-vessel disease at angiography. Of the 283 patients without angiographically significant disease, 124 had negative ultrafast CT coronary studies, for a specificity of 44%. An increasing number of vessels with calcification present on ultrafast CT was found to increase specificity for the presence of obstructive coronary artery disease in at least one vessel (P &amp;amp;amp;lt; .0001). As the log of the calcium score increases, the probability of multivessel obstructive disease increases (P &amp;amp;amp;lt; .0001). Ultrafast CT scanning is an noninvasive, non-exercise-dependent test with an excellent sensitivity for the detection of coronary artery disease. The presence of calcifications in multiple vessels and in younger populations correlates with higher specificities for obstructive disease, making ultrafast CT coronary scanning a very useful diagnostic test.
CHEST Journal, 1994
The presence of a perivalvular abscess is associated with an increased risk of morbidity and mort... more The presence of a perivalvular abscess is associated with an increased risk of morbidity and mortality with valve replacement and can require extensive debridement and reconstructive procedures. An accurate noninvasive method for preoperative diagnosis may hasten operation and aid in preoperative and surgical management. Two cases are presented in which ultrafast computed tomography accurately identified perivalvular abscesses not detected on two-dimensional transthoracic echocardiography and guided operative intervention.
The American Journal of Cardiology, 1998
We compared intracoronary ultrasound (ICUS) and electron-beam computed tomography (EBCT) on a cor... more We compared intracoronary ultrasound (ICUS) and electron-beam computed tomography (EBCT) on a coronary segmental basis in 40 consecutive patients with acute coronary syndromes and no or minimal to moderate angiographic disease (53 ؎ 10 years; 34 men, 6 women). ICUS was used to define plaques, and EBCT was used to quantify coronary calcium (using a threshold of a CT density >130 Hounsfield units in an area >1.03 mm 2 ). In a site-by-site analysis, coronary segments were defined as normal if both methods were negative, as containing noncalcified plaques if only ICUS was positive, and as containing calcified plaques if both methods were positive. A total of 222 coronary segments were analyzed (5.6 ؎ 1.9 segments per patient). In 36 patients (90%), a total of 95 segments with plaques were identified, whereas in 4 patients (10%), only normal segments were seen. Of the 95 segments with plaques, 61 (64%) were calcified, and 34 (36%) were noncalcified. There was a linear relationship between the num-ber of segments with calcified and with noncalcified plaques (r ؍ 0.86, p <0.0001), but the mean relative frequency of segments with calcified plaques (55 ؎ 38%) was highly variable. Calcium was found in 15 of 16 patients (93%) with 3 or more segments with plaques, while it was found in only 12 of 20 patients (60%) with one or 2 segments with plaques (p ؍ 0.026). Younger age, higher low-density lipoprotein-cholesterol levels, diabetes, and active smoking predicted a higher relative frequency of segments with noncalcified plaques. Thus, in patients with acute coronary syndromes but no angiographically critical stenoses, there is a linear relationship between segments with calcified plaques versus segments with noncalcified plaques. However, while the mean ratio of these segments is close to 1:1, it is highly variable among individual patients.
The American Journal of Cardiology, 1998
This blinded, single center study prospectively compares exercise electron beam computed tomograp... more This blinded, single center study prospectively compares exercise electron beam computed tomography (EBCT) with stress technetium-99m (Tc-99m) sestamibi singlephoton emission computed tomography (SPECT) in 33 patients undergoing coronary angiography for evaluation of chest pain. Patients undergoing routine cardiac catheterization for the diagnosis of chest pain were imaged at rest using EBCT. Patients exercised on a semisupine ergometer, and exercise EBCT was immediately followed by injection of Tc-99m sestamibi for assessment of myocardial ischemia. At peak exercise, Tc-99m SPECT, followed immediately by nonionic contrast material, was injected intravenously to directly compare these 2 imaging techniques. Patients were reimaged with Tc-99m SPECT at rest 24 to 48 hours after stress. Exercise EBCT, which was analyzed using a global ejec-tion fraction measure, had a sensitivity of 81% and a specificity of 76%, compared with angiography. Using the development of a new regional wall motion abnormality as evidence of obstructive coronary artery disease (CAD), EBCT yielded a specificity of 100% and a sensitivity of 88%. Reversible perfusion defects identified by SPECT, as evidence of obstructive CAD, revealed a sensitivity of 75% and a specificity of 71%. The specificity of regional wall motion analysis by EBCT was significantly better than SPECT (p <0.01) in this population. This study demonstrates regional wall motion assessed by EBCT to be as sensitive and more specific than SPECT myocardial perfusion imaging in identifying obstructive CAD as defined by angiography. ᮊ1998 by Excerpta Medica, Inc.
American Heart Journal, 1994
Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiogr... more Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiographic technology can detect coronary calcium before atherosclerosis becomes symptomatic.
The American Journal of Cardiology, 2001
The purpose of this study is to perform a cost-effectiveness analysis of long-term moderate exerc... more The purpose of this study is to perform a cost-effectiveness analysis of long-term moderate exercise training (ET) in patients with stable chronic heart failure. In particular, the study focuses on the survival analysis and cost savings from the reduction in the hospitalization rate in the exercise group. In the past 10 years, ET has been shown to be beneficial for patients with stable class II and III heart failure in many randomized clinical trials. However, the cost-effectiveness of a long-term ET program has not been addressed for outcomes related to morbidity/mortality end points or health care utilization. We examined the cost-effectiveness of a 14-month longterm training in patients with stable chronic heart failure. The estimated increment cost for the training group, 3,227/patient,wascalculatedbysubtractingtheavertedhospitalizationcost,3,227/patient, was calculated by subtracting the averted hospitalization cost, 3,227/patient,wascalculatedbysubtractingtheavertedhospitalizationcost,1,336/patient, from the cost of ET and wage lost due to ET, estimated at 4,563/patient.ForpatientsreceivingET,theestimatedincrementinlifeexpectancywas1.82years/personinatimeperiodof15.5years,comparedwithpatientsinthecontrolgroup.Thecost−effectivenessratioforlong−termETinpatientswithstableheartfailurewasthusdeterminedat4,563/ patient. For patients receiving ET, the estimated increment in life expectancy was 1.82 years/person in a time period of 15.5 years, compared with patients in the control group. The cost-effectiveness ratio for long-term ET in patients with stable heart failure was thus determined at 4,563/patient.ForpatientsreceivingET,theestimatedincrementinlifeexpectancywas1.82years/personinatimeperiodof15.5years,comparedwithpatientsinthecontrolgroup.Thecost−effectivenessratioforlong−termETinpatientswithstableheartfailurewasthusdeterminedat1,773/life-year saved, at a 3% discount rate. Long-term ET in patients with stable chronic heart failure is cost-effective and prolongs survival by an additional 1.82 years at a low cost of $1,773 per/life-year saved.