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Biomedical subjects

D S Berman

Publications and source records attributed to D S Berman.

At least 73 records · Page 4Linked to original sources
PubMed1996

Gender-related differences in exercise ventricular function among healthy subjects and patients.

Increasing numbers of women are undergoing noninvasive stress testing for coronary artery disease evaluation. Limited information is available regarding the presence, magnitude, and importance of gender-related differences in exercise ventriculography among the heterogeneous population of patients referred for noninvasive stress testing. Patients referred for exercise radionuclide ventriculography between 1979 and 1986 were evaluated, including 175 patients with a likelihood of coronary artery disease, 59 patients with angiographically normal coronary arteries, and 419 patients with coronary artery disease. Overall, women demonstrated higher resting left ventricular ejection fraction and lower delta left ventricular ejection fraction response to exercise compared with men. Although left ventricular response to exercise correlated with the underlying severity of coronary artery disease in both women and men, fewer women demonstrated a delta left ventricular ejection fraction >5 percent despite a lower prevalence of multivessel coronary artery disease compared with men. We conclude that gender-related differences in left ventricular response to exercise are present in a wide range of patients referred for testing.

Adult↗
PubMed1996

Statistical, epidemiological and fiscal issues in the evaluation of patients with coronary artery disease.

The application of myocardial perfusion scintigraphy to patient care in the era of health care cost containment is a difficult issue. The traditional diagnosis based approach to testing, although effective, is incompletely applied, as evidenced by the number of low likelihood of coronary artery disease patients referred for testing. A prognosis- or risk-based testing approach may be applied to both patients with or without known coronary artery disease by utilizing clinical and scan information to estimate the projected risk of adverse outcomes (cardiac death or myocardial infarction) and planning subsequent patient strategy based upon this estimate. Patients at high risk for these events are more likely to benefit from referral to catheterization while those patients at lower risk may benefit from medical therapy alone. Irrespective of the approach utilized to evaluate testing, consideration of patient population selection and its implications must be considered when reviewing the results of testing or published literature. Further, scrutiny of both the statistical methods used for evaluation of the value of testing and the economic implications of testing in particular patient subgroups are of importance.

Coronary Disease↗
PubMed1995

Gender-related differences in clinical management after exercise nuclear testing.

OBJECTIVES: This study sought to determine the rate of referral to cardiac catheterization in men and women early after nuclear testing as a function of the magnitude of myocardial ischemia by radionuclide perfusion imaging. BACKGROUND: Although many previous studies have suggested that gender-related differences are present in the clinical management of coronary artery disease, the presence of such a difference with respect to referral to catheterization after noninvasive testing is disputed. METHODS: We examined 3,211 consecutive patients (1,074 women, 2,137 men) who underwent exercise dual-isotope single-photon emission computed tomography and had follow-up evaluation performed at least 1 year after nuclear testing (mean [+/- SD] follow-up 19 +/- 5 months) for "hard" events (cardiac death and myocardial infarction) and referral to cardiac catheterization or revascularization within 60 days of nuclear testing. Multiple logistic regression analysis was performed to determine the best predictors of referral to catheterization as well as to examine whether gender itself added further information to this model. RESULTS: Although men were referred to catheterization more frequently than women (10.6% vs 7.1%, p < 0.001) early after exercise nuclear testing, there were no differences in the rate of referral to catheterization or revascularization after stratification by the amount of abnormally perfused myocardium detected by the nuclear scan. Both men and women with normal scan results were infrequently referred to subsequent catheterization. In the setting of severe ischemia, women were referred to catheterization more frequently than men. This higher rate appears to be clinically appropriate because women with severely abnormal scan results had a significantly higher event rate than men (17.5% vs. 6.3%, p < 0.0001). This greater risk in women than in men appeared to be underappreciated because the increased rate of hard events in women with severely abnormal scan results was out of proportion to the smaller increase in their rate of referral to cardiac catheterization. Although gender added information to the multivariate model most predictive of referral to catheterization models when nuclear variables were not included, when nuclear variables were considered, the addition of gender added no further significant information. This finding suggests that adjusting for differences in perfusion scan abnormalities by the use of nuclear testing eliminated the apparent gender-related referral bias. CONCLUSIONS: After controlling for differences in perfusion scan abnormalities, no gender-related referral bias to catheterization was present. In the setting of severe ischemia, women had a greater rate referral to catheterization than men. As a function of risk, both men and women were appropriately referred to catheterization at a low rate when the scan result was normal. However, because women with severe perfusion abnormalities had a greater rate of cardiac death and myocardial infarction then men, women in this high risk subgroup were underreferred to catheterization relative to men. This finding points to the need to better identify women at high cardiac risk.

Aged↗
PubMed1995

The limited efficacy of exercise radionuclide ventriculography in assessing prognosis of women with coronary artery disease.

Increasing numbers of women are undergoing stress testing for coronary artery disease evaluation. Limited study is available as to its efficacy in women. Four hundred nineteen patients with coronary artery disease (74 women and 345 men) referred for exercise radionuclide ventriculography between 1979 and 1986 were evaluated in a prospective cohort evaluation with 5-year follow-up. Exercise radionuclide ventriculographic variables were analyzed and compared between women and men. The prognostic efficacy of exercise radionuclide ventriculography was assessed separately for women and men among patients with coronary artery disease by Kaplan-Meier cumulative survival curves, univariate Cox regression analyses, and hierarchical stepwise Cox regression analyses. Overall, women demonstrated higher resting and peak left ventricular ejection fraction response to exercise than men. Ninety-six of 419 patients (23%) had cardiac events at 5-year follow-up. Although left ventricular response to exercise conveyed prognostic information in the combined and male populations (multivariate hierarchical analyses chi-square 11, p = 0.001 for delta left ventricular ejection fraction and chi-square 10, p = 0.002 for worsening exercise wall motion score), these variables were not found to be prognostically useful in women. Women with coronary artery disease demonstrated a worsened functional status, evidenced by greater compromise of exercise capacity, despite having less extensive anatomic disease than their male counterparts. We conclude that sex-related differences in left ventricular response to exercise limit the prognostic utility of exercise ventriculography in women with coronary artery disease.

Aged↗
PubMed1995

Arbutamine stress thallium-201 single-photon emission computed tomography using a computerized closed-loop delivery system. Multicenter trial for evaluation of safety and diagnostic accuracy. The International Arbutamine Study Group.

OBJECTIVES: This study sought to evaluate the efficacy and safety of arbutamine when used in conjunction with thallium-201 single-photon emission computed tomography (SPECT) in a multicenter trial and to compare arbutamine stress and treadmill exercise thallium-201 SPECT for diagnostic sensitivity and myocardial perfusion pattern. BACKGROUND: Arbutamine is a potent beta-agonist developed specifically for pharmacologic stress testing. METHODS: Arbutamine was administered by a novel computerized closed-loop device that measures heart rate and adjusts arbutamine infusion to achieve a selected rate of heart rate increase toward a predetermined limit. The cohort included 184 patients who underwent arbutamine stress testing, of whom 122 (catheterization group) had angiographically defined coronary artery disease ( > or = 50% diameter stenosis of a major coronary artery), and 62 had a low pretest likelihood of coronary artery disease (low likelihood group). A subset of 69 patients from the catheterization group underwent both arbutamine and exercise stress testing. RESULTS: Hemodynamic responses during arbutamine and exercise stress testing demonstrated no significant difference in percent increase in heart rate (81% vs. 76%) or systolic blood pressure (26% vs. 30%). The sensitivity for detecting coronary artery disease ( > or = 50% stenosis) using arbutamine thallium-201 SPECT was 87% (95% for detecting > or = 70% stenoses), and the normalcy rate in the low likelihood group was 90%. In patients completing both arbutamine and exercise stress testing, thallium-201 SPECT sensitivity for detecting coronary artery disease ( > or = 50% stenosis) was 94% and 97% (p = NS), respectively Furthermore, SPECT segmental visual score agreement (defect vs. no defect) showed a concordance of 92% between arbutamine and exercise results (kappa 0.80, p < 0.001). The stress thallium-201 SPECT segmental scores showed 83% exact agreement (kappa 0.69, p < 0.001), and analysis of the reversibility of segments with stress perfusion defects demonstrated 86% exact agreement (kappa 0.68, p < 0.001). In general, side effects associated with arbutamine were well tolerated and resolved with discontinuation of infusion. CONCLUSIONS: Arbutamine, administered by a closed-loop feed-back system was shown to be a safe and effective pharmacologic stress agent. Arbutamine stress thallium-201 SPECT appears to be accurate for the diagnosis of coronary artery disease with a diagnostic efficacy similar to that of treadmill exercise thallium-201 studies.

Adult↗
PubMed1995

Prior restraint: a Bayesian perspective on the optimization of technology utilization for diagnosis of coronary artery disease.

In conclusion, at least 1/3 of patients with suspected coronary artery disease are inappropriately referred for scintigraphic diagnostic testing from a Bayesian such as those described in this report, may be a powerful mechanism for encouraging more appropriate technology utilization while simultaneously controlling costs, and are thereby deserving of a formal prospective demonstration trial. However, since only half the patients currently being tested are referred for diagnostic purposes, analogous strategies must be developed with respect to prognostic and therapeutic evaluation.

Aged↗
PubMed1995

Clinical applications of exercise nuclear cardiology studies in the era of healthcare reform.

The challenge for nuclear cardiology is to demonstrate that it can provide more information than competitive modalities at comparable or lower cost. In considering patients for nuclear cardiology procedures, presentations can be divided into 9 subsets: within each subset, nuclear cardiology tests should be employed where incremental information is provided over the information available without performing the test. (1) Patients with no known coronary artery disease (CAD); for diagnosis, nuclear imaging is useful in patients with intermediate probability of CAD. For prognosis, assessment is based on extent of ischemia, where we have shown that nuclear testing provides incremental information, especially in patients with a high likelihood of CAD, such as those with typical angina. In the remaining categories (2-9), nuclear cardiology studies are predominantly used for purposes of risk stratification. Here the greatest value is in patients deemed to be at intermediate risk before nuclear testing. (2) Postmyocardial infarction: stress nuclear imaging provides an alternative to angiography for risk assessment of clinically uncomplicated patients. (3) Poor ventricular function: Nuclear testing is particularly useful for differentiating patients with hibernating myocardium (the defect is reversible), with stunned myocardium (no defect is present), or with myocardial infarction (the defect is persistent). (4) Unstable angina: Following current federal guidelines, nuclear imaging in medically stabilized low-to-intermediate risk patients with unstable angina is likely to increase. (5) Postcatheterization patients: Nuclear imaging is useful when there is uncertainty regarding the choice of medical management or revascularization. (6) Pre-noncardiac surgery patients: Nuclear imaging is clearly helpful in patients with intermediate clinical risk and may provide useful information in clinically high-risk patients. (7) Post-PTCA patients: Due to the intermediate likelihood of restenosis, nuclear scans are frequently employed 2-6 months following intervention. (8) Post-CABG patients: We have demonstrated that exercise scintigraphy (SPECT) provides incremental prognostic information over clinical and exercise electrocardiographic results and is useful when clinical risk of events is considered intermediate. (9) Long-term management: Scintigraphy provides objective information regarding progression or regression of CAD.

Angina, Unstable↗
PubMed1995

Adenosine pharmacologic stress myocardial perfusion tomographic imaging in patients with significant aortic stenosis. Diagnostic efficacy and comparison of clinical, hemodynamic and electrocardiographic variables with 100 age-matched control subjects.

OBJECTIVES: This study assessed the safety and diagnostic accuracy of adenosine stress myocardial perfusion scintigraphy for the detection of coronary artery disease using single-photon emission computed tomography (SPECT) in patients with significant aortic stenosis. BACKGROUND: Exercise cardiac stress testing in patients with significant aortic stenosis is generally avoided because of concerns for safety. In addition, those studies that have analyzed the utility of exercise testing both with and without myocardial thallium-201 scintigraphy for the diagnosis of coronary artery disease have yielded low specificity. Currently, no safe and accurate means exists to noninvasively assess the presence, extent and severity of coronary artery disease in patients with significant aortic stenosis. METHODS: The study included 35 patients with moderate to severe aortic stenosis (mean [+/- SD] aortic valve area 0.84 +/- 0.16 cm2, range 0.5 to 1.2; mean maximal instantaneous aortic valve gradient 44.4 +/- 15.9 mm Hg, range 20 to 84). All patients underwent a 6-min adenosine infusion (140 micrograms/kg body weight per min) protocol and either separate acquisition rest thallium-201/stress technetium-99m sestamibi or stress and 4-h redistribution thallium-201 SPECT: Visual 20-segment SPECT analysis used a standard five-point scoring system from 0 (normal tracer uptake) to 4 (absent uptake). The SPECT results were considered abnormal if more than two segments had a stress score > or = 2. Hemodynamic, electrocardiographic and clinical responses were compared with those in a reference group of 100 consecutive age-matched patients undergoing adenosine SPECT who did not have aortic stenosis. RESULTS: Hemodynamic responses during adenosine stress testing between the study and control patients demonstrated no significant difference in the net change in systolic blood pressure (18% of baseline vs. 14%, patients with aortic stenosis vs. control subjects), heart rate (21% vs. 19%), rate-pressure product (0% vs. 2%) or incidence of chest pain (23% vs. 35%) or transient second-(9% vs. 9%) or third-degree atrioventricular block (3% vs. 1%). In the 20 patients who had coronary angiography, sensitivity for detection of coronary artery disease was 92% (12 of 13) and specificity was 71% (5 of 7). CONCLUSIONS: In this preliminary study, adenosine was found to be well tolerated and diagnostically accurate in patients with moderate to severe aortic stenosis.

Adenosine↗
PubMed1995

Incremental prognostic value of exercise thallium-201 myocardial single-photon emission computed tomography late after coronary artery bypass surgery.

OBJECTIVES: This study assessed the incremental prognostic value of exercise thallium-201 myocardial perfusion single-photon emission computed tomography (SPECT) performed > or = 5 years after coronary artery bypass surgery. BACKGROUND: Thallium-201 scintigraphy has shown significant prognostic value in a variety of populations with suspected and known coronary artery disease. However, its value in patients with previous bypass surgery remains unknown. METHODS: We studied 294 patients who were prospectively followed up. Cox proportional hazards models for prediction of "hard" events (cardiac death and nonfatal infarctions) were constructed, with variables considered for inclusion in hierarchic order: clinical and exercise data first, followed by scintigraphic information. RESULTS: Mean (+/- SD) follow-up duration after scintigraphy was 31 +/- 11 months. There were 20 cardiac deaths and 21 nonfatal acute myocardial infarctions. Twenty-nine patients had late (> 60 days after thallium-201 SPECT) revascularization procedures or underwent repeat bypass surgery or percutaneous transluminal angioplasty. Shortness of breath and peak exercise heart rate were the most important clinical predictors of hard events. Two scintigraphic variables added significant prognostic information to the clinical model: the thallium-201 summed reversibility score (summation of segmental differences between stress and redistribution scores) and the presence of increased lung uptake of the radiotracer. The global chi-square statistic for this model was twice as high as that for the clinical/exercise model alone (49.7 vs. 24.2). When a second multivariate Cox model was built adding "soft" events (i.e., late revascularization procedures) as outcomes of interest, the summed reversibility score was selected as an independent scintigraphic predictor of events. The global chi-square statistic for this model was 50.7, three times as high as that for the clinical/exercise model alone. CONCLUSIONS: After evaluation of treadmill and exercise data, thallium-201 myocardial perfusion SPECT provided incremental prognostic information in patients late after bypass.

Aged↗
PubMed1995

Incremental value of simultaneous assessment of myocardial function and perfusion with technetium-99m sestamibi for prediction of extent of coronary artery disease.

OBJECTIVES: This study assessed the incremental value of technetium-99m myocardial single-photon emission computed tomography (SPECT) and simultaneous first-pass radionuclide angiography, when added to treadmill exercise, for prediction of the extent of coronary artery disease. BACKGROUND: Technetium-99m count statistics permit the simultaneous assessment of myocardial perfusion and function. However, whether this characteristic improves prediction of the extent of coronary artery disease remains unknown. METHODS: We studied 70 consecutive patients who had coronary angiography within 6 months of the scintigraphic study. All patients underwent a symptom-limited treadmill exercise test. Treadmill data were summarized using a previously validated score. Left ventricular ejection fraction and regional wall motion were evaluated from a first-pass radionuclide angiogram acquired at peak treadmill exercise in the anterior view. Perfusion was assessed visually. Extent of angiographic disease was expressed as the presence or absence of multivessel disease (more than two coronary artery territories with > 50% stenosis) and as a score that reflects the location of severe (> 75%) stenosis. RESULTS: Stepwise addition of scintigraphic data (perfusion first, followed by function) to the treadmill score showed significant incremental value for prediction of the angiographic score at each step; exercise ejection fraction alone was the strongest independent predictor. Discriminant accuracy for detection of multivessel disease was also improved by the addition of perfusion information to the treadmill score and addition of regional wall motion analysis to both of them. In this case, ejection fraction failed to show independent value. CONCLUSIONS: The addition of simultaneously performed sestamibi perfusion SPECT and first-pass radionuclide angiography to the treadmill exercise test significantly improved prediction of the extent of coronary artery disease.

Coronary Angiography↗
PubMed1995

Incremental value of prognostic testing in patients with known or suspected ischemic heart disease: a basis for optimal utilization of exercise technetium-99m sestamibi myocardial perfusion single-photon emission computed tomography.

OBJECTIVES: This study assessed the incremental prognostic implications of normal and equivocal exercise technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) and sought to determine its incremental prognostic value, impact on patient management and cost implications. BACKGROUND: The prognostic implications of Tc-99m sestamibi SPECT are not well defined, and risk stratification using this test has not been explored. METHODS: We studied 1,702 patients referred for exercise Tc-99m sestamibi SPECT who were followed up for a mean (+/- SD) of 20 +/- 5 months. Patients with previous percutaneous transluminal coronary angioplasty or coronary artery bypass surgery were excluded. The SPECT studies were assessed using semiquantitative visual analysis. Cardiac death and myocardial infarction were considered "hard" events, and coronary angioplasty and bypass surgery > 60 days after testing were considered "soft" events. RESULTS: Of the 1,702 patients studied, 1,131 had normal or equivocal scan results. A total of 10 events occurred in this group (1 cardiac death and 1 myocardial infarction [0.2% hard events]; 4 coronary angioplasty and 4 bypass surgery procedures [0.7% soft events]). The rates of hard events and referral to catheterization after SPECT were similarly low in patients with a low (< 0.15), intermediate (0.15 to 0.85) and high (> 0.85) post-exercise treadmill test (ETT) likelihood of coronary artery disease. With respect to scan type, patients with normal, probably normal or equivocal scan results had similarly low hard event rates. In the 571 patients with abnormal scan results, there were 43 hard events (7.5%) and 42 soft events (7.4%) (p < 0.001 vs. 1,131 patients with normal scan results for both). When the complete spectrum of scan responses was considered, SPECT provided incremental prognostic value in all patient subgroups analyzed. However, the nuclear scan was cost-effective only in patients with interpretable exercise ECG responses and an intermediate to high post-ETT likelihood of coronary artery disease and in those with uninterpretable exercise ECG responses and an intermediate to high pre-ETT likelihood of coronary artery disease. CONCLUSIONS: Normal or equivocal exercise Tc-99m sestamibi study results are associated with a benign prognosis, even in patients with a high likelihood of coronary artery disease. Although incremental prognostic value is added by nuclear testing in all patient subgroups, a testing strategy incorporating nuclear testing proved to be cost-effective only in the groups with an intermediate to high likelihood of coronary artery disease before scanning.

Aged↗
PubMed1995

Operator-less processing of myocardial perfusion SPECT studies.

UNLABELLED: We have developed a completely automated algorithm to generate reoriented tomographic images from projections in myocardial perfusion SPECT. METHODS: The algorithm consists of three software modules. The first module determines reconstruction limits for the projection dataset using two-dimensional feature extraction techniques. The second module reconstructs the projection images into transaxial images using standard filtered backprojection. The third module reorients the transaxial images into short-axis images. RESULTS: The algorithm was validated on 350 rest 201Tl and 350 stress 99mTc-sestamibi studies acquired on a single-detector (178 studies), a 90 degrees dual-detector (230 studies) or a triple-detector camera (292 studies). The complete processing sequence was successful in 93.6% of the studies (166/178 + 216/230 + 273/292). As for the individual modules, myocardial boundaries were correctly determined in 96.3% of the studies (171/178 + 222/230 + 281/292), while reorientation was successful in 97.2% of the studies (166/171 + 216/222 + 273/281). No significant difference in success rates for 201Tl versus 99mTc-sestamibi images was found. CONCLUSION: Our automated approach to myocardial perfusion SPECT processing is highly successful, intrinsically reproducible and can produce time and cost savings while improving accuracy in a clinical or research environment.

Algorithms↗
PubMed1995

Automatic quantification of ejection fraction from gated myocardial perfusion SPECT.

UNLABELLED: We have developed a completely automatic algorithm to quantitatively measure left ventricular ejection fraction (LVEF) from gated 99mTc-sestamibi myocardial perfusion SPECT images. METHODS: The algorithm operates in the three-dimensional space and uses gated short-axis image volumes. It segments the left ventricle (LV), estimates and displays endocardial and epicardial surfaces for all gating intervals in the cardiac cycle, calculates the relative left ventricular cavity volumes and derives the global EF from the end-diastolic and end-systolic volume, all without operator interaction. The algorithm for measuring LVEF was tested in 65 clinical patients undergoing 16-interval and 8-interval rest-gated SPECT and validated against first-pass radionuclide ventriculography. RESULTS: Automatic segmentation and contouring of the LV was successful in 65/65 (100%) of the studies. Agreement between EFs measured from 8-interval gated SPECT and EFs calculated from first-pass data was high (y = 2.44 + 1.03x, r = 0.909, p < 0.001, s.e.e. = 6.87). Agreement between EF values measured from 16-interval and 8-interval gated SPECT was excellent (y = -2.7 + 0.97x, r = 0.988, p < 0.001, s.e.e. = 2.65), the latter being on average lower by 3.71 percentage points. CONCLUSION: Our automatic method is rapid and highly agrees with conventional radionuclide measurements of EF, thus providing clinically useful additional information to complement myocardial perfusion studies.

Algorithms↗
PubMed1995

Automatic reorientation of three-dimensional, transaxial myocardial perfusion SPECT images.

UNLABELLED: We developed a completely automatic technique to reorient transaxial images into short-axis (oblique) myocardial perfusion SPECT images. METHODS: The algorithm starts by isolating (segmenting) the left ventricle (LV) myocardium using a combination of iterative clusterification and rule-based location/size/shape criteria. The three-dimensional, mid-myocardial LV surface is initially estimated as the locus of the trilinearly interpolated maxima for the count profiles originating from the center of mass of the segmented LV. The final mid-myocardial surface is obtained by iteratively applying this process, incorporating additional constraints of shape and texture and using the nonsegmented, nonthresholded transaxial image to obtain information on hypoperfused areas of the myocardium. It is then fitted to an ellipsoid, of which the major axis is assumed to represent the long axis of the LV, and the three-dimensional image volume is resliced perpendicularly to it. RESULTS: The algorithm was retrospectively applied to 400 dual-isotope studies (200 rest 201TI, 200 stress 99mTc-sestamibi) from 200 consecutive patients. Segmentation was successful in 394/400 (98.5%) of the patients. The reproducibility of computer-based reorientation was perfect and significantly better than either intraobserver or interobserver reproducibility. CONCLUSION: Automatic reorientation offers the potential for consistently faster and more accurate image processing and analysis and is an important step towards totally operator-less management of myocardial perfusion SPECT data.

Algorithms↗