Search PubMed⌕ Search

Biomedical subjects

R Detrano

Publications and source records attributed to R Detrano.

At least 55 records · Page 3Linked to original sources
PubMed1986

Prospective comparison of exercise digital subtraction and exercise first pass radionuclide ventriculography.

In order to test the comparative sensitivities of first-pass radionuclide and digital subtraction ventriculography in detecting wall motion abnormalities during exercise, 29 patients referred for coronary angiography were submitted to both types of stress ventriculograms. Resting and exercise ventriculograms by both techniques were reviewed by independent observers and the five equal ventricular wall segments were graded as normal, mildly, moderately, severely hypokinetic, akinetic, or dyskinetic. Of the 29 patients, 24 had arteriographically defined ischemic potential (at least greater than 50% obstruction of a major coronary artery supplying viable myocardium). Exercise digital subtraction ventriculography correctly identified 17 (71%) of these by a worsening of wall motion during exercise, while radionuclide ventriculography identified only eight (33%) by the wall motion response. When either a worsening of wall motion or the failure to increase ejection fraction by at least 5 points were used as criteria for an abnormal test, the sensitivities of digital and radionuclide ventriculographies were 96% and 79%, respectively. Though the number of patients without ischemic potential (5 patients) was too small to judge the relative specificities, digital subtraction ventriculography appears to be more sensitive than radionuclide ventriculography in identifying exercise-induced wall motion abnormalities and in predicting coronary occlusions.

Angiography↗
PubMed1986

Exercise electrocardiographic variables: a critical appraisal.

To compare four recently proposed methods of analyzing the exercise electrocardiogram with the conventional analysis of ST segment depression, 303 consecutive patients without myocardial infarction who had been referred for coronary arteriography underwent stress electrocardiography and stress thallium imaging. The specificity for the prediction of a greater than 50% coronary obstruction of 0.5, 1.0, 1.5 and 2.0 mm ST segment depression measured in the conventional way was 0.59, 0.73, 0.88 and 0.94, respectively. The specificity of a thallium perfusion defect was 0.79. Sensitivities of the conventional ST depressions, thallium defect, the change in the sum of the R amplitudes and the slope adjusted for heart rate increase were calculated and compared at the cited levels of specificity. R wave changes had a significantly lower sensitivity than did the conventionally analyzed ST depression at each level of specificity. Slope-adjusted ST depression had a slightly higher sensitivity than that of conventional ST depression only at a specificity of 0.73 (0.68 versus 0.65, p = 0.07). R wave-adjusted ST depression was significantly more sensitive than conventional ST depression only at a specificity of 0.94 (0.45 versus 0.36, p = 0.01). Heart rate-adjusted ST depression was more sensitive than conventional ST depression at all of the specificities except 0.59. This pattern of superior accuracy of heart rate-adjusted ST depressions was preserved for the prediction of multivessel coronary disease. Heart rate adjustment is a simpler and more accurate modification of the conventional electrocardiographic analysis than are the other three methods studied.

Adult↗
PubMed1986

Exercise digital subtraction ventriculography for the detection of ischaemic wall motion abnormalities in patients without myocardial infarction.

Digital subtraction angiography permits high resolution imaging of the left ventricle after an intravenous injection of contrast medium. The capacity of digital subtraction angiography to detect ischaemic wall motion abnormalities was tested in 150 consecutive patients without myocardial infarction who were referred for coronary angiography. Digital ventriculograms were considered to be abnormal if there was a severe wall motion abnormality at rest or if segmental wall motion deteriorated after exercise. The global ventricular response to exercise was considered to be abnormal if the ventricular ejection fraction computed by the Dodge area length formula was less than 50% at rest or failed to increase after exercise. Seventy eight (52%) of these subjects had stenosis of greater than 50% of at least one major coronary artery. In 36 (24%) more than one major coronary vessel was affected. Sensitivities for the detection of stenoses greater than 50% coronary obstruction were 82% and 69% for an abnormal segmental wall motion response and an abnormal ejection fraction response respectively. The specificity of these test responses was 76% and 68% respectively. No complications resulted from the digital ventriculographic studies. It is concluded that safe adequate digital ventricular imaging at rest and after exercise is possible and that an abnormal wall motion response is a sensitive indicator of important coronary obstructive disease.

Angiocardiography↗
PubMed1986

Detection of multivessel disease after myocardial infarction using intravenous stress digital subtraction angiography.

Forty-six patients with prior myocardial infarction underwent stress intravenous digital subtraction angiography (DSA) and coronary angiography. The left ventricular ejection fraction (EF) and wall-motion responses to exercise were correlated with the coronary anatomy. Twenty-five patients with single vessel disease showed essentially no change in left ventricular EF with exercise (a decrease from 66% to 64%), but those with multivessel disease (21 patients) had a significant decrease in left ventricular EF (from 59% to 48%) (P = .0001). A decrease in left ventricular EF had a sensitivity of 95% and specificity of 60% for the detection of multivessel disease, whereas an increase in wall-motion abnormality had a sensitivity and specificity of 72% and 71%, respectively. After myocardial infarction, a fall in left ventricular EF with stress intravenous DSA is highly sensitive for the detection of multivessel disease, but there are a number of false-positive results, resulting in only moderate specificity. A new wall motion abnormality has only a moderate sensitivity and specificity.

Adult↗
PubMed1986

Bayesian analysis versus discriminant function analysis: their relative utility in the diagnosis of coronary disease.

Both Bayesian analysis assuming independence and discriminant function analysis have been used to estimate probabilities of coronary disease. To compare their relative accuracy, we submitted 303 subjects referred for coronary angiography to stress electrocardiography, thallium scintigraphy, and cine fluoroscopy. Severe angiographic disease was defined as at least one greater than 50% occlusion of a major vessel. Four calculations were done: (1) Bayesian analysis using literature estimates of pretest probabilities, sensitivities, and specificities was applied to the clinical and test data of a randomly selected subgroup (group I, 151 patients) to calculate posttest probabilities. (2) Bayesian analysis using literature estimates of pretest probabilities (but with sensitivities and specificities derived from the remaining 152 subjects [group II]) was applied to group I data to estimate posttest probabilities. (3) A discriminant function with logistic regression coefficients derived from the clinical and test variables of group II was used to calculate posttest probabilities of group I. (4) A discriminant function derived with the use of test results from group II and pretest probabilities from the literature was used to calculate posttest probabilities of group I. Receiver operating characteristic curve analysis showed that all four calculations could equivalently rank the disease probabilities for our patients. A goodness-of-fit analysis suggested the following relationship between the accuracies of the four calculations: (1) less than (2) approximately equal to (4) less than (3). Our results suggest that data-based discriminant functions are more accurate than literature-based Bayesian analysis assuming independence in predicting severe coronary disease based on clinical and noninvasive test results.

Bayes Theorem↗
PubMed1985

Comparison of stress digital ventriculography, stress thallium scintigraphy, and digital fluoroscopy in the diagnosis of coronary artery disease in subjects without prior myocardial infarction.

Exercise thallium scintigraphy is often used for the diagnosis of coronary artery disease (CAD). Exercise digital subtraction ventriculography and digital subtraction fluoroscopy are new diagnostic procedures with roles that have not been determined. To compare the relative accuracies of the digital techniques with thallium scintigraphy, 97 consecutive patients without myocardial infarction underwent all 3 tests on the day before their scheduled coronary angiograms. Forty-two patients had CAD (more than 50% diameter narrowing of 1 major artery). A fixed or reversible perfusion defect defined an abnormal thallium test response and a segmental wall motion abnormality at rest or with exercise defined an abnormal digital ventriculographic response. Any visualized coronary calcific deposit defined an abnormal digital fluorographic response. The sensitivities of digital fluoroscopy (86%) and digital ventriculography (79%) were significantly higher than the sensitivity of thallium (62%) (p less than 0.05). The specificity of thallium (82%) was not significantly higher than that of either digital ventriculography (72%) or fluoroscopy (67%). The diagnostic accuracies of digital fluoroscopy, digital ventriculography, and thallium were 75%, 75% and 73%, respectively. A logistic regression model showed that thallium and digital fluoroscopy were more accurate in younger patients, whereas digital ventriculography was more sensitive in hypertensive persons and in those not taking beta-blocking drugs. The choice of test depends on disease prevalence, clinical variables (such as age and hypertension) and the importance of functional information obtained from stress testing.

Age Factors↗
PubMed1985

Cardiac digital subtraction angiography: peripheral versus central intravenous dye injections.

Peripheral and central intravenous injections of contrast material were performed during the cardiac digital subtraction angiographic (DSA) studies of 24 patients keeping constant X-ray exposure factors, volume of dye, and angiographic projection. The resulting continuous-mask-subtracted runs of cardiac images were videotaped and reviewed by three observers. In a forced-choice comparison, the central injection was judged to produce images of superior technical quality 42 times as opposed to 30 times for the peripheral injection. When comparing the diagnostic quality of the studies, the reviewers found no significant difference in diagnostic adequacy in 65 judgments (90%). They found the central injection to be superior in diagnostic quality in four judgments (twice in the same patient) and the peripheral injection superior in three judgments (all in the same patient). Although central intravenous injections produce slightly better cardiac digital subtraction angiographic images, we have found peripheral injections diagnostically adequate for most of these studies and favor them for simplicity and ease of performance.

Adult↗
PubMed1985

Videodensitometric ejection fraction from intravenous digital subtraction right ventriculograms: correlation with first pass radionuclide ejection fraction.

Thirty-one consecutive patients undergoing intravenous blurred mask digital subtraction right ventriculography were submitted to first pass radionuclide angiography. Second order mask resubtraction of end-diastolic and end-systolic right ventricular digital image frames was executed using preinjection end-diastolic and end-systolic frames to rid the digital subtraction images of mis-registration artifact. End-diastolic and end-systolic perimeters were drawn manually by two independent observers with a light pen. Ejection fractions calculated from the integrated videodensitometric counts within these perimeters correlated well with those derived from the first pass radionuclide right ventriculogram (r = 0.84) and the interobserver correlation was acceptable (r = 0.91). Interobserver differences occurred more frequently in patients with atrial fibrillation and in those whose tricuspid valve planes were difficult to discern on the digital subtraction right ventriculograms. These results suggest that videodensitometric analysis of digital subtraction right ventriculograms is an accurate method of determining right ventricular ejection fraction and may find wide clinical applicability.

Absorptiometry, Photon↗
PubMed1985

Videodensitometric ejection fractions from intravenous digital subtraction left ventriculograms: correlation with conventional direct contrast and radionuclide ventriculography.

Forty-three patients who had undergone direct-contrast ventriculography were submitted to intravenous digital subtraction ventriculography and first-pass radionuclide ventriculography to compare the left ventricular ejection fractions obtained by each method. Ejection fractions were calculated by the area-length method from the direct contrast ventriculograms, by both area-length and videodensitometric methods from the digital subtraction ventriculograms, and by count densitometry from the radionuclide ventriculograms. Satisfactory correlations were found between values obtained by the late mask resubtracted videodensitometric method and the radionuclide method (r = 0.85) and by the digital ventriculographic area length method and direct-contrast method (r = 0.88). Videodensitometric methods may be an alternative way to estimate left ventricular ejection fractions accurately without reliance on geometric assumptions about the shape of the left ventricular cavity.

Analog-Digital Conversion↗
PubMed1985

Digital subtraction fluoroscopy: a new method of detecting coronary calcifications with improved sensitivity for the prediction of coronary disease.

The association between calcification of the coronary arteries and coronary artery narrowing is well established. However, fluoroscopic visualization of coronary calcifications has been insufficiently sensitive to be useful as a screening test. Since digitization of radiographic images permits the subtraction of noncardiac structures from moving cardiac structures, such subtraction might increase the sensitivity of coronary fluoroscopy. To determine whether coronary calcifications were better visualized with digital subtraction fluoroscopy than with conventional fluoroscopy, we taped diseased human coronary arteries to a pulsating water balloon inside the thorax of a dog cadaver and studied this model with both fluoroscopic techniques. Calcific atherosclerotic plaques were more easily identified with digital subtraction fluoroscopy than with conventional fluoroscopy. We tested the method clinically by submitting 191 subjects without history or electrocardiographic evidence of previous myocardial infarction who were referred for coronary arteriography to both fluoroscopic studies. For at least one, at least two, and three calcified coronary arteries, digital fluoroscopy was more sensitive (92%, 66%, and 40%) than conventional fluoroscopy (63%, 21%, and 2%) (all p less than .001) for the prediction of significant coronary obstructions (greater than 50%). Although digital fluoroscopy was less specific than conventional fluoroscopy (digital: 65%, 89%, and 97%; conventional: 81%, 98%, and 100%) (all but last, p less than .01), receiver operating curve analysis revealed a significantly larger area under the curve, indicating higher accuracy for the digital technique (p = .03). Digital subtraction fluoroscopy was more accurate in younger than in older patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1985

Intravenous digital subtraction aortography in the preoperative and postoperative evaluation of Marfan's aortic disease.

Seventeen patients with the skeletal stigmata of Marfan's syndrome or the physical and radiographic findings of Marfan's aortic disease (or both) were studied using intravenous digital subtraction aortography. Digital subtraction aortography revealed a dilated aortic root in 16 of the 17 patients. One of the 17 had mildly dilated aortic sinuses with a normal ascending aorta. All of the four children (less than or equal to 16 years of age) had aortic diameters which were greater than the 95th percentile for their body surface area. The average aortic root diameter in the adult patients was 6.8 cm (range, 4-11 cm). Three of the 17 had aortic dissection, two of which were detected by digital subtraction aortography and two by aortic root injection. Four of 13 adults and three children had pulmonary arterial diameters which exceeded 4 cm. Six patients underwent ascending aorta and valvular replacement and were studied with digital subtraction aortography after surgery. All preoperative and postoperative studies were of adequate diagnostic quality. Aortic root diameters calculated from intravenous digital subtraction angiograms correlated well with those derived from echocardiography (r2 = 0.92). We conclude that intravenous digital subtraction aortography is effective in diagnosing and following Marfan's aortic disease both before and after surgery.

Adolescent↗