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T H Marwick

Publications and source records attributed to T H Marwick.

At least 55 records · Page 3Linked to original sources
PubMed2000

Three-dimensional echocardiography: research toy or clinical tool?

Conventional 2D echocardiography is an excellent qualitative imaging method, but its use for quantitation is limited by test-retest reproducibility of image planes. The increasing sophistication of medical treatments for left ventricular dysfunction, hypertension and valvular heart disease has created the need for accurate and reproducible measurements of chamber dimensions. Similarly, improvements in valve repair and catheter-based interventions for valve lesions and septal defects have created the need for better visualisation of cardiac structures. The use of 31) echocardiography may decrease variability both in the quality and interpretation of complex pathology among investigators. Three-dimensional echocardiography is achieved by using a 3D spatial registration device with a conventional 21) scanner, or by using a high-speed, phased-array real-time scanner. The latter are still developmental, so that the technique currently requires use of a 21) scanner, combined with a 31) spatial coordinate system, which may be external or internal to the scanning transducer. An external system permits data acquired from several cardiac windows to be integrated and reconstructed. Image reconstruction is performed using a wire-frame model or surface rendering. Wire-frame models are formed by manual or automatic connection of boundary data points; this approach uses fewer data points than rendering, can be rapidly processed and is sufficient for quantitative analysis. Surface-rendering uses lighting and shading applied to a wire-frame model to produce a realistic 31) display, which may be useful for surgical planning and increasing understanding of anatomic relations. Three-dimensional echocardiography yields more accurate measurements of ventricular volume and function, as well as new measurements such as infarct area. With increased reproducibility and reliability, 3D echocardiography may well prove to be the essential tool required for the serial follow up of left ventricular mass and volume.

Journal Article↗
PubMed2000

Prediction of global left ventricular function after bypass surgery in patients with severe left ventricular dysfunction. Impact of pre-operative myocardial function, perfusion, and metabolism.

AIMS: Previous studies have compared the accuracy of various tests of viability for the prediction of recovery of regional left ventricular function; global left ventricular recovery has been less well studied, although it has important prognostic and functional ramifications. We sought to identify the relative contribution of ischaemia, regional and global contractile reserve, perfusion and metabolic function to changes in left ventricular volumes and global function after coronary artery bypass surgery in patients with severe left ventricular dysfunction. METHODS AND RESULTS: Dipyridamole stress Rb-82, fluorodeoxyglucose positron emission tomography and low and high-dose dobutamine-atropine stress echocardiography were obtained in 66 patients with left ventricular impairment. Myocardial segments were considered viable if ischaemia or either metabolic or contractile reserve were present, on positron emission tomography or dobutamine echocardiography. Resting left ventricular function was reassessed after surgery (mean 10+/-3 weeks) in the 59 patients who had not suffered a major peri-operative event; functional improvement was defined by a 5% increment of ejection fraction. Myocardial viability was found in 37 (63%) patients using positron emission tomography and in 42 (71%) patients using dobutamine echocardiography; post-operative functional improvement was noted in 28 (47%) patients. In univariate analyses, predictors of global post-operative functional recovery included: the extent of viability according to positron emission tomography [OR (odds ratio): 2.08 for each additional viable segment, 95% CI (confidence interval): 1.33-3. 25, P=0.001] or dobutamine echocardiography (OR: 2.06 for each additional viable segment, 95% CI: 1.28-3.30, P=0.003) and the increase in ejection fraction with low-dose dobutamine (OR: 1.9 for each 1% increase in ejection fraction with low dose dobutamine, 95% CI 1.39-2.61, P<0.0001). In a multivariate model which included evidence of viability by either technique, and change in ejection fraction with low-dose dobutamine echocardiography, only change in ejection fraction with low-dose dobutamine echocardiography was predictive of post-operative left ventricular functional recovery (adjusted OR: 1.81, 95% CI: 1.30-2.52, P=0.0005). CONCLUSION: Among patients with severe left ventricular dysfunction who are referred for surgical revascularization, the overall accuracies of positron emission tomography and dobutamine echocardiography for the prediction of post-operative myocardial recovery are comparable. However, the strongest predictor of overall improvement of post-operative left ventricular function is an increase of ejection fraction with a low-dose dobutamine infusion.

Aged↗
PubMed2000

Cost-effectiveness of stress echocardiography for assessment of coronary artery disease: what we know and what we need to know.

AIMS: This review explores the balance between the incremental data supplied by stress echocardiography and its cost. This technique is now established as an accurate tool for the diagnosis of coronary artery disease and myocardial viability, but the current medical-economic environment mandates careful consideration of the impact of the results on patient outcomes. METHODS AND RESULTS: The tools for assessment of cost and efficiency are reviewed. Two considerations are explored for controlling costs; avoidance of testing in those who will derive limited incremental data, and appropriate selection of stress echocardiography rather than other stress techniques. The balance between diagnostic accuracy and cost is explored in observational studies and computer models. Finally, the prognostic implications of testing are evaluated and data from the stress testing literature are explored to show that more effective patient selection for interventions may justify greater expenditure on testing. CONCLUSIONS: The appropriate selection of patients for testing has a significant evidence base. The cost of identifying coronary disease has been examined in a number of studies and facilitates the selection between testing modalities. Prognostic data are increasingly available, and further work is needed to combine this with cost analysis in order to show that stress echocardiography, like other stress modalities, may be used to guide therapy and thereby improve cost-effective outcomes.

Computer Simulation↗
PubMed2000

Application of stress echocardiography to the evaluation of non-coronary heart disease.

Stress echocardiography is accepted as a routine test in patients with coronary artery disease for the identification of myocardial ischaemia, the diagnosis of viable myocardium and assessment of prognosis. This review addresses the application of the test to non-coronary heart diseases. Some caution should be applied to the use of stress echocardiography for the detection of ischaemia in patients with valvular heart disease. However, examination of haemodynamics and left ventricular function during exercise is worthwhile in the assessment of symptomatic patients with apparently mild or moderate valvular disease, as well as being useful for the detection of subclinical left ventricular dysfunction. In the future, this tool may be more widely applied to the identification of other 'subclinical' conditions, including pulmonary hypertension, anthracycline cardiotoxicity and valvular heart diseases, although the benefit of early diagnosis of these conditions remains to be established.

Cardiomyopathies↗
PubMed2000

Exercise echocardiography predicts development of left ventricular dysfunction in medically and surgically treated patients with asymptomatic severe aortic regurgitation.

OBJECTIVE: To assess resting and exercise echocardiography for prediction of left ventricular dysfunction in patients with significant asymptomatic aortic regurgitation. DESIGN: Cohort study of patients with aortic regurgitation. SETTING: Tertiary referral centre specialising in valvar surgery. PATIENTS: 61 patients (38 men, 23 women; mean (SD) age 53 (14) years) with asymptomatic or minimally symptomatic aortic regurgitation and no known coronary artery disease; 35 were treated medically and 26 had aortic valve replacement. INTERVENTIONS: Exercise echocardiography was used to evaluate ejection fraction, which was measured on the resting and post-stress images using the modified Simpson method. Patients with an increment of ejection fraction after exercise were denoted as having contractile reserve (CR+); those without an increment were labelled CR-. MAIN OUTCOME MEASURES: Standard univariate and multivariate methods and receiver operating characteristic analyses were used to assess the ability of contractile reserve to predict follow up ejection fraction. RESULTS: In the 35 medically treated patients, 13 of 21 (62%) with CR+ (mean (SD) ejection fraction increment 7 (3)%) had preserved ejection fraction on follow up. In the 14 patients with CR- (ejection fraction decrement 8 (4)%), 13 (93%) had a decrement of ejection fraction on follow up from 60 (5)% at baseline to 54 (3)% on follow up (p = 0.005). Age, resting left ventricular dimensions, medical treatment, aortic regurgitation severity, exercise capacity, and rate-pressure product were similar in both CR+ and CR- groups. Among the 26 surgical patients, 13 showed CR+ (ejection fraction increase 9 (5)%), all of whom had an increase in ejection fraction on follow up (from 49% to 59%). Of 13 surgical patients with CR- (ejection fraction decrease 7 (5)%), 10 (77%) showed the same or worse ejection fraction on postoperative follow up. CONCLUSIONS: Contractile reserve on exercise echocardiography is a better predictor of left ventricular decompensation than resting indices in asymptomatic patients with aortic regurgitation. In patients undergoing aortic valve replacement, contractile reserve had a better correlation with resting ejection fraction on postoperative follow up. Measurement of contractile reserve may be useful to monitor the early development of myocardial dysfunction in asymptomatic patients with aortic regurgitation, and may help to optimise the timing of surgery.

Adult↗
PubMed1999

Usefulness of an exaggerated systolic blood pressure response to exercise in predicting myocardial perfusion defects in known or suspected coronary artery disease.

The clinical importance of an exaggerated systolic blood pressure (BP) response to exercise, or exercise hypertension, is unclear. We have previously reported that exercise hypertension is associated with less severe angiographic coronary artery disease. This study sought to examine the association between exercise hypertension and ischemic "burden," as assessed by thallium-201 single-photon emission computed tomography. The cohort was comprised of consecutive adults (2,216 men, 1,229 women) referred for symptom-limited exercise thallium testing to evaluate known or suspected coronary artery disease. The main variable measured was exercise hypertension, defined as a peak systolic BP > or =210 mm Hg in men and > or =190 mm Hg in women. Thallium perfusion defects were described as: (1) any perfusion abnormality, (2) reversible abnormalities, and (3) any abnormality in > or =3 of 12 myocardial segments ("extensive abnormalities"). Exercise hypertension was present in 1,319 subjects (39%). Patients with exercise hypertension were less likely to have any thallium perfusion abnormality (16% vs 25%, odds ratio [OR] 0.58, 95% confidence intervals [CI] 0.49 to 0.69, p <0.001), reversible thallium abnormalities (7% vs 12%, OR 0.71, 95% CI 0.57 to 0.90, p <0.001), and extensive abnormalities (8% vs 14%, OR 0.53, 95% CI 0.42 to 0.67, p <0.001). After adjusting for possible confounders, the same trend was seen. During 6 years of follow-up there were 283 deaths with no association between exercise hypertension and mortality risk. Thus, exercise hypertension is associated with a lower likelihood of myocardial perfusion abnormalities and is not associated with an increased mortality rate.

Adult↗
PubMed1999

Effect of color coding and subtraction on the accuracy of contrast echocardiography.

BACKGROUND: Contrast echocardiography may be used to assess myocardial perfusion. However, gray scale assessment of myocardial contrast echocardiography (MCE) is difficult because of variations in regional backscatter intensity, difficulties in distinguishing varying shades of gray, and artifacts or attenuation. We sought to determine whether the assessment of rest myocardial perfusion by MCE could be improved with subtraction and color coding. METHODS AND RESULTS: MCE was performed in 31 patients with previous myocardial infarction with a 2nd generation agent (NC100100, Nycomed AS), using harmonic triggered or continuous imaging and gain settings were kept constant throughout the study. Digitized images were post processed by subtraction of baseline from contrast data and colorized to reflect the intensity of myocardial contrast. Gray scale MCE alone, MCE images combined with baseline and subtracted colorized images were scored independently using a 16 segment model. The presence and severity of myocardial contrast abnormalities were compared with perfusion defined by rest MIBI-SPECT. Segments that were not visualized by continuous (17%) or triggered imaging (14%) after color processing were excluded from further analysis. The specificity of gray scale MCE alone (56%) or MCE combined with baseline 2D (47%) was significantly enhanced by subtraction and color coding (76%, p<0.001) of triggered images. The accuracy of the gray scale approaches (respectively 52% and 47%) was increased to 70% (p<0.001). Similarly, for continuous images, the specificity of gray scale MCE with and without baseline comparison was 23% and 42% respectively, compared with 60% after post processing (p<0.001). The accuracy of colorized images (59%) was also significantly greater than gray scale MCE (43% and 29%, p<0.001). The sensitivity of MCE for both acquisitions was not altered by subtraction. CONCLUSION: Post-processing with subtraction and color coding significantly improves the accuracy and specificity of MCE for detection of perfusion defects.

Contrast Media↗
PubMed1999

Correlation of preoperative myocardial function, perfusion, and metabolism with postoperative function at rest and stress after bypass surgery in severe left ventricular dysfunction.

Previous studies of dobutamine echocardiography (DE) and positron emission tomography (PET) showed similar accuracy for predicting improvement in resting wall motion after revascularization, although limited direct comparative data are available. We sought to compare the relative accuracy of detecting contractile reserve, ischemia, perfusion, and myocardial metabolism for predicting functional recovery after coronary bypass surgery in 94 consecutive patients (aged 63+/-11 years) with chronic coronary disease and depressed left ventricular function (ejection fraction 28+/-5%). PET imaging comprised rest and dipyridamole stress myocardial perfusion images, with fluorodeoxyglucose to define metabolism-perfusion mismatch. A standard dobutamine-atropine stress was used, with evaluation of low- and peak-dose echocardiographic responses. Regional function was assessed after 13+/-16 weeks at rest in 68 patients who underwent isolated coronary bypass operation without evidence of perioperative infarction, and at rest and stress in a subgroup of 29 patients. Concordance between methods for evaluating abnormal segments (ischemic, viable, and scar) and accuracy of both tests for predicting improvement in regional function were identified. Concordance between PET and DE for identifying viable or nonviable myocardium was 63% using a 16-segment model. For predicting improved resting function after surgery, the sensitivity of PET (84%) was superior to DE (69%, p<0.001), but DE was more specific (78% vs. 37%, p<0.0001) and more accurate (75% vs. 53%, p<0.001) in predicting recovery at rest. Analysis of postoperative recovery of segmental function during stress also showed the specificity of DE to exceed that of PET (89% vs. 32%, p<0.001). The accuracy of DE was enhanced by evaluation of function during stress (86%, p<0.001), but this was not altered with PET (52%, p = NS). Thus, PET is more sensitive than DE in predicting functional recovery, but DE is more specific than PET. Evaluation of left ventricular functional recovery during stress may be preferable to assessment at rest.

Cardiotonic Agents↗
PubMed1999

Association of exercise-induced ventricular ectopic activity with thallium myocardial perfusion and angiographic coronary artery disease in stable, low-risk populations.

This study sought to determine the association of exercise-induced ventricular ectopic activity with thallium perfusion defects and severity of angiographic coronary artery disease (CAD). Two cohorts consisting of adults without heart failure or known severe ventricular ectopic activity at rest were studied. The first cohort consisted of adults (n = 2,743) who underwent maximum exercise thallium stress testing. The second cohort consisted of adults (n = 423) who underwent coronary angiography within 90 days of treadmill testing. Significant exercise-induced ventricular ectopic activity was defined as frequent ventricular premature complexes or nonsustained ventricular tachycardia. Severe CAD was defined as left main CAD (> or = 50% stenosis), 3-vessel CAD (> or = 70% stenosis), or 2-vessel CAD with > or = 70% stenosis of the proximal left anterior descending artery. In the thallium cohort, exercise-induced ventricular ectopic activity was associated with a greater frequency of thallium defects (35.2% vs 18.7%, odds ratio [OR] 2.35, 95% confidence intervals [CI] 1.62 to 3.42, p <0.001); after adjusting for possible confounders, this association persisted (for any defect adjusted OR 1.66, 95% CI 1.09 to 2.53, p = 0.02; for septal defect adjusted OR 2.77, 95% CI 1.51 to 5.07, p <0.001). There was no association between exercise-induced ventricular ectopic activity and mortality during 2 years of follow-up. In the angiographic cohort, there was no association of exercise-induced ventricular ectopy with severe CAD (19% vs 20%, OR 0.93, 95% CI 0.41 to 2.09, p = NS). Exercise-induced ventricular ectopic activity was associated with a greater likelihood of thallium perfusion defects, but was not associated with angiographic severity of coronary disease or with short-term mortality.

Adult↗
PubMed1999

Impaired chronotropic response to exercise stress testing as a predictor of mortality.

CONTEXT: Chronotropic incompetence, an attenuated heart rate response to exercise, is a predictor of all-cause mortality in healthy populations. This association may be independent of exercise-induced myocardial perfusion defects. OBJECTIVE: To examine the prognostic significance of chronotropic incompetence in a low-risk cohort of patients referred for treadmill stress testing with thallium imaging. DESIGN: Prospective cohort study conducted between September 1990 and December 1993. SETTING: Tertiary care academic medical center. PATIENTS: Consecutive patients (1877 men and 1076 women; mean age, 58 years) who were not taking beta-blockers and who were referred for symptom-limited treadmill thallium testing. MAIN OUTCOME MEASURES: Association of chronotropic incompetence, defined as either failure to achieve 85% of the age-predicted maximum heart rate or a low chronotropic index, a heart rate response measure that accounts for effects of age, resting heart rate, and physical fitness, with all-cause mortality during 2 years of follow-up. RESULTS: Three hundred sixteen patients (11%) failed to reach 85% of the age-adjusted maximum heart rate, 762 (26%) had a low chronotropic index, and 612 (21%) had thallium perfusion defects. Ninety-one patients died during the follow-up period. After adjustment for age, sex, thallium perfusion defects, and other confounders, failure to reach 85% of the age-predicted maximum heart rate was associated with increased risk of death (adjusted relative risk [RR], 1.84; 95% confidence interval [CI], 1.13-3.00; P=.01), as was a low chronotropic index (adjusted RR, 2.19; 95% CI, 1.43-3.44; P<.001). CONCLUSION: Among patients with known or suspected coronary disease, chronotropic incompetence is independently predictive of all-cause mortality, even after considering thallium perfusion defects. Incorporation of chronotropic response into the routine interpretation of stress thallium studies may improve the prognostic power of this test.

Cardiovascular Diseases↗
PubMed1999

Influence of dobutamine or exercise stress on the results of pulsed-wave Doppler assessment of myocardial velocity.

BACKGROUND: Pulsed-wave Doppler assessment of myocardial velocity (MDV) may permit a more quantitative interpretation of stress echocardiography. This technique has been used with dobutamine echo (DbE), but exercise echo (ExE) may be preferred in patients who are able to exercise maximally. The influence of these stressors on the results of MDV are undefined. PURPOSE: This study sought to determine whether differences between the physiology of DbE and ExE could influence the MDV responses to stress and whether interpretative criteria should be different with exercise or dobutamine stress. METHODS: DbE or ExE was performed in 105 patients tested for known or suspected coronary artery disease. Pulsed-wave MDV was obtained in basal segments of anteroseptal, septal, anterior, posterior, lateral, and inferior walls in the apical views at rest and at peak doses of dobutamine or immediately after exercise. Segments were classified as normal or abnormal (ischemia or scar) according to results of 2-dimensional echocardiography, and MDV obtained at rest and stress was compared by using analysis of variance. RESULTS: Resting heart rate was similar before both dobutamine and exercise, but heart rate at peak dobutamine exceeded that after exercise (137 +/- 10 vs 115 +/- 22, P <.01). For both ExE and DbE, MDV was significantly greater at rest and stress in normal than in abnormal segments. Stress MDV in both normal and abnormal segments was greater with DbE than with ExE (17.0 +/- 4.8 cm/s vs 10. 3 +/- 3.4 cm/s, P <.001 for normal segments and 10.7 +/- 4.4 cm/s vs 7.9 +/- 3.3 cm/s, P <.001 for abnormal segments. Increase in MDV/Deltaheart rate induced by DbE was greater than by ExE in normal (0.14 +/- 0.07 cm/s. beat for DbE and 0.09 +/- 0.08 cm/s. beat for ExE; P <.05) but similar in abnormal segments (0.06 +/- 0.07 cm/s. beat for DbE and 0.05 +/- 0.09 cm/s. beat for ExE). MDV correlated better with peak heart rate at ExE (r = 0.56, P <.01) than at DbE (r = 0.28, P <.01). CONCLUSIONS: MDV responses to exercise and pharmacologic stress appear to be different, reflecting differences in inotropy, loading, and the timing of imaging. These findings may influence the ability of MDV to differentiate normal from abnormal stress echocardiography responses.

Aged↗
PubMed1999

Latent left ventricular dysfunction in patients with mitral regurgitation: feasibility of measuring diminished contractile reserve from a simplified model of noninvasively derived left ventricular pressure-volume loops.

BACKGROUND: Assessment of left ventricular (LV) contractility in mitral regurgitation is difficult, and latent systolic dysfunction may be present despite conventional indexes being in the "normal" range. We sought to demonstrate the presence of latent LV dysfunction in mitral regurgitation by showing diminished contractile reserve with the use of simplified pressure-volume loops from noninvasively derived parameters. METHODS AND RESULTS: We performed exercise echocardiography in 72 patients with isolated mitral regurgitation, minimal or no symptoms, normal resting LV function, and no coronary disease who subsequently underwent uncomplicated valve repair and in 15 healthy subjects. Simplified pressure-volume loops were constructed and LV stroke work was estimated at rest and immediately after exercise. As pressures were estimated, the findings were confirmed with a validated numerical model to estimate stroke work in patients and control subjects. Patients had a higher stroke work than did control subjects at rest (1.45 +/- 0.39 vs 0.92 +/- 0.21 J, P <.001). Eighteen patients had LV dysfunction develop after surgery. Patients with postrepair dysfunction had a significantly lower exercise stroke work (1.79 +/- 0.69) than did patients without (2.28 +/- 0.84 J, P =.02), but there was no difference in resting stroke work (1.48 +/- 0.39 vs 1.44 +/- 0.4, P = not significant). Change in stroke work with exercise was higher in patients with normal postoperative function (0.84 +/- 0.59 J) and control subjects (0.59 +/- 0.36 J) than patients with postoperative dysfunction (0.31 +/- 0.55 J, P =.001). The numerical model confirmed the lower exercise stroke work and change in stroke work in patients with postoperative dysfunction. CONCLUSIONS: The clinical study and numerical model confirmed diminished contractile reserve in patients who had LV dysfunction develop after uncomplicated mitral valve repair. Diminished contractile reserve may be a preoperative marker of latent contractile dysfunction.

Cardiac Volume↗
PubMed1999

Prognosis of patients with vascular disease after clinical evaluation and dobutamine stress echocardiography.

BACKGROUND: Coronary disease is an important cause of long-term morbidity in patients needing major vascular surgery. We sought to assess the efficacy of preoperative clinical evaluation and the detection of inducible ischemia for prediction of immediate and long-term cardiac outcomes of patients undergoing vascular surgery. METHODS: In 233 patients undergoing vascular procedures, we assessed risk clinically on the basis of Eagle's criteria. Dobutamine echocardiography was performed with a standard protocol and results were classified as showing ischemia, scar, or a normal response. Patients were observed perioperatively, and late follow-up (28 +/- 13 months) was completed in all surgical survivors. A composite end point of cardiac death, myocardial infarction, and unstable and progressive angina requiring late revascularization was used to judge event-free survival. RESULTS: Of 233 patients undergoing preoperative dobutamine echocardiography, 39 (17%) had inducible ischemia and 36 (15%) had scar. Perioperative events occurred in 8 patients (3%). None of the patients with ischemia had perioperative events, reflecting the effect of revascularization in 9 patients. Late events occurred in 36 patients; ischemia on preoperative stress testing was a predictor of these events even after adjusting for clinical variables and left ventricular dysfunction (relative risk = 3.3; 95% confidence interval 1.6 to 6.8; P =.001). The association of ischemia with clinical predictors was associated with incrementally worse outcome. CONCLUSION: In addition to perioperative assessment, the combined use of clinical and dobutamine echocardiographic evaluation may stratify the risk of late cardiac events.

Adrenergic beta-Agonists↗
PubMed1999

The noninvasive prediction of cardiac mortality in men and women with known or suspected coronary artery disease. Economics of Noninvasive Diagnosis (END) Study Group.

PURPOSE: The association between myocardial perfusion imaging defects and cardiac mortality in women is undefined. We examined whether myocardial perfusion imaging predicted cardiac mortality in men and women and compared this with other variables influencing prognosis. SUBJECTS AND METHODS: Six academic institutions with high-volume nuclear cardiology laboratories consecutively studied 5,009 men aged 62 +/- 12 years (mean ISD) and 3,402 women aged 66 +/- 11 years with symptomatic known or suspected coronary artery disease undergoing exercise (n = 7,486) or pharmacologic stress (n = 925) myocardial perfusion imaging. A pretest clinical risk index was calculated from age, history of myocardial infarction, diabetes, hypertension, and hypercholesterolemia. Myocardial perfusion images were analyzed for stress-induced defects or any defect in the territories of the three major coronary arteries. RESULTS: Stress-induced perfusion defects were seen in 39% of men and 25% of women (P = 0.0001). Extensive stress-induced or fixed defects (>2 vascular territories) were less common in women than men (10% vs 19%, and 4% vs 18%, both P = 0.0001). During a mean of 2.4 +/- 1.5 years of follow-up, 143 patients died of cardiac causes. The clinical risk index and number of territories with perfusion defects were associated with cardiac mortality in women and men. In women undergoing exercise myocardial perfusion imaging, the number of abnormal territories remained the strongest correlate of mortality after adjustment for exercise variables. CONCLUSIONS: The results of myocardial perfusion imaging are important, independent predictors of survival in both women and men.

Aged↗
PubMed1999

Screening for coronary artery disease.

Unidentified coronary artery disease remains a significant cause of premature death and morbidity during the prime of life. The availability of effective interventions for the management of ischemia has provoked new interest in screening for this condition in asymptomatic patients, in the hope of reducing the burden of this condition. Although widespread use of stress testing is ineffective, the use of imaging techniques may offer better accuracy for detection of ischemia. Other tests that identify evidence of atheroma in the peripheral or coronary circulation may be useful to identify patients at risk.

Australia↗
PubMed1999

Dobutamine stress echocardiography for the detection of significant coronary artery disease in renal transplant candidates.

Prophylactic coronary revascularization may reduce the risk for cardiac events in diabetic renal transplant candidates. No published data exist on the accuracy of dobutamine stress echocardiography (DSE) for the diagnosis of angiographically defined coronary artery disease (CAD) in renal transplant candidates. The purpose of this study is to examine the accuracy of DSE for the detection of CAD in high-risk renal transplant candidates compared with coronary angiography. Fifty renal transplant candidates with diabetic nephropathy (39 patients) or end-stage renal disease (ESRD) from other causes (11 patients) underwent prospectively performed DSE, followed by quantitative coronary angiography (QCA) and qualitative visual assessment of CAD severity. Twenty of 50 DSE tests were positive for inducible ischemia. Twenty-seven patients (54%) had a stenosis of 50% or greater by QCA, 12 patients (24%) had a stenosis of greater than 70% by QCA, and 16 patients (32%) had a stenosis greater than 75% by visual estimation. The sensitivity and specificity of DSE for CAD diagnosis were respectively 52% and 74% compared with QCA stenosis of 50% or greater, 75% and 71% compared with QCA stenosis greater than 70%, and 75% and 76% for stenosis greater than 75% by visual estimate. On long-term follow-up (22.5 +/- 10.1 months), 6 of 30 patients (20%) with negative DSE results and 11 of 20 patients (55%) with positive DSE results had a cardiac death, myocardial infarction (MI), or coronary revascularization. Six of 27 patients (22%) with a QCA stenosis of 50% or greater had a cardiac death or MI compared with none of the 23 patients (0%) with QCA stenosis less than 50% (P = 0.025). We conclude that DSE is a useful but imperfect screening test for angiographically defined CAD in renal transplant candidates.

Adult↗