Biomedical subjects

B R Chaitman

Publications and source records attributed to B R Chaitman.

At least 163 records · Page 9Linked to original sources

PubMed1987

Multilesion coronary angioplasty: clinical and angiographic follow-up.

Determination of the restenosis rate after multilesion percutaneous transluminal coronary angioplasty is an important consideration in defining expanded indications for the procedure. Of 209 patients who underwent successful multilesion coronary angioplasty, 55 symptomatic and 74 asymptomatic patients were restudied an average of 7 +/- 4 months after dilation. The restenosis rate was 82% (45 of 55) in the symptomatic patients and 30% (22 of 74) in the asymptomatic patients (p less than 0.001). Only 4% of the asymptomatic patients had restenosis at more than one dilation site. When only patients who developed a restenosis were considered, the restenosis occurred at more than one dilation site in 47% (21 of 45) of the symptomatic group versus 14% (3 of 22) of the asymptomatic group (p less than 0.05). When all recurrent stenoses were examined, the severity of the luminal narrowing was greater than or equal to 70% in 64% (45 of 70) of the stenotic lesions in the symptomatic patients versus 31% (8 of 26) of the stenotic lesions in the asymptomatic patients (p less than 0.05). Proximal left anterior descending coronary artery disease, increased length of the stenotic narrowing, male gender and diabetes were associated with an increased incidence of restenosis by multivariate analysis. Patient-related variables were not predictive of multilesion restenosis. In conclusion, the majority of patients are clinically improved after multilesion coronary angioplasty. Recurrent symptoms after multilesion coronary angioplasty are frequently associated with multilesion restenosis and a more severe degree of restenotic narrowing. Restenosis at more than one dilation site is uncommon in the asymptomatic patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1987

Improved interpretation of exercise Tl-201 myocardial perfusion scintigraphy in women: characterization of breast attenuation artifacts.

Thallium-201 myocardial perfusion scintigraphy is reported to be a less accurate diagnostic test for coronary artery disease in women than in men. We retrospectively analyzed 34 Tl-201 studies obtained in 28 symptomatic women and compared them with those obtained in 32 men during the same interval. Three criteria were tested: criterion 1 was defined as abnormal scans showing any defect; criterion 2, scans showing only transient (reversible) defects; and criterion 3, scans showing either transient or "significant" (i.e., not due to breast attenuation) fixed defects. The sensitivity in women was 1.00, 0.73, and 0.93, respectively; the specificity, 0.26, 0.84, and 0.85. The best values in men were a sensitivity of 1.00 and a specificity of 0.86. The three criteria were then prospectively tested in 33 scans of 29 additional women. The sensitivity was 0.90, 0.65, and 0.80, respectively, and the specificity, 0.18, 1.00, and 0.92. Defects (usually fixed) due to breast attenuation artifact were seen frequently (30%). Criterion 3 best differentiates such defects from those resulting from coronary artery disease, making Tl-201 myocardial perfusion scintigraphy as accurate in women as in men.

Adult↗

PubMed1987

Evaluation of left ventricular function during upright exercise: correlation of exercise Doppler with postexercise two-dimensional echocardiographic results.

The relationship of regional and global left ventricular function to aortic flow dynamics during exercise was determined in 14 normal subjects and 14 patients with coronary artery disease. Doppler and two-dimensional echocardiographic studies were performed before, during, and immediately after an exercise test by the Bruce protocol. Two-dimensional echocardiography was used to determine the ejection fraction and new wall motion abnormalities. The peak ejection velocity, stroke index, and cardiac index were calculated from the pulsed Doppler tracing. In normal subjects the ejection fraction increased significantly (p less than .001) from rest (0.51 +/- 0.07) to peak exercise (0.61 +/- 0.07), while the response in coronary patients was blunted (0.49 +/- 0.11 vs 0.48 +/- 0.16). Similarly, the change in peak ejection velocity throughout exercise in normal subjects (from 0.71 +/- 0.12 to 1.50 +/- 0.35 m/sec) was significantly (p less than .01) greater than that in patients with coronary artery disease (from 0.61 +/- 0.13 to 0.90 +/- 0.29 m/sec). There was a good correlation between the percent change in peak ejection velocity and the percent change in ejection fraction from rest to peak exercise in the entire study group (rs = .64) and in the patients with coronary artery disease (rs = .84). These preliminary data suggest that exercise-induced changes in Doppler echocardiographic variables may offer a potential adjunct in the evaluation of patients with ischemic heart disease.

Adult↗

PubMed1987

Prolonged myocardial ischemia after intravenous dipyridamole thallium imaging.

Intravenous dipyridamole thallium imaging is reported to be a safe test with minimal side effects. It has been proposed by some that the test simply dilates the coronary vessels without actually producing myocardial ischemia. In this report, we describe a patient who, following intravenous dipyridamole thallium imaging, developed severe myocardial ischemia which persisted for 90 minutes, requiring emergency coronary angioplasty to alleviate the ischemic insult. Sequential electrocardiograms and cardiac isoenzyme levels following coronary angioplasty were within normal limits. Thus, severe myocardial ischemia following intravenous dipyridamole testing can occur and emphasizes the importance of careful monitoring of these patients, particularly when the pretest risk of coronary disease is high.

Cardiomyopathies↗

PubMed1986

Effect of coronary artery disease on Doppler-derived parameters of aortic flow during upright exercise.

Recent advances in Doppler echocardiography have made possible noninvasive determination of stroke volume, cardiac output and peak ejection velocity at rest. To determine the ability of Doppler to measure these variables and the effect of altered left ventricular (LV) function during upright treadmill exercise, 20 normal subjects (group I) and 17 patients with coronary artery disease (CAD) (group II) were studied. Stroke index response was similar in both groups. The increase in cardiac index was more rapid in group I subjects and reached a higher peak value at maximal exercise (8.6 +/- 2.5 vs 5.5 +/- 2.2 liters/min, p less than 0.001). Peak ejection velocity increased rapidly during exercise in group I subjects; it increased much less in group II patients. Differences were significant at each stage of exercise. Peak ejection velocity was 1.56 +/- 0.32 and 0.89 +/- 0.26 m/s in group I vs group II patients, respectively, at maximal exercise. Three responses were seen in group II subjects. Three patients, all with 1-vessel CAD and normal LV function at rest, showed a normal response, with an increase in peak ejection velocity of at least 80% (type I response). In 8 patients peak ejection velocity increased less than 80% (type II response) and in 6 patients it decreased at maximal exercise (type III). Type II and III responses were seen in patients with more severe CAD and LV dysfunction at rest. These data show a progressive difference in Doppler-derived variables in exercise between normal subjects and patients with CAD, which is greatest in patients with LV dysfunction at rest and multivessel CAD.

Adult↗

PubMed1986

Risk of preangioplasty occlusion and myocardial infarction in one-vessel-disease patients scheduled for percutaneous transluminal coronary angioplasty.

Coronary occlusion or myocardial infarction occurred in 50 of 394 (13%) one-vessel-disease patients awaiting percutaneous transluminal coronary angioplasty (PTCA). To identify risk factors for these events, we first matched the 37 patients who demonstrated occlusion on the immediate preangioplasty repeat angiogram with 37 patients who did not. Matching was based on the time interval between angiograms, the date of the procedure, and the site of the lesion. Preangioplasty occlusion patients did differ from controls by age (47 +/- 11 vs 54 +/- 8 years, P less than .01), smoking status (34/37 vs 24/37, P less than .01), and angina class (2.6 +/- 1.0 vs 2.3 +/- 0.7, P less than .10) at the time of the first angiogram. Second, we pooled the data of the 37 preangioplasty occlusion patients with those of the 13 patients with preangioplasty myocardial infarction. The 50 cases with complication (coronary occlusion or myocardial infarction) were younger (47 +/- 12 vs 54 +/- 8 years, P less than .01), more often smokers (42/50 vs 24/37, P less than .05), and more symptomatic (2.7 +/- 0.8 vs 2.3 +/- 0.7, P less than .05) than the 37 controls. This study suggests that young smokers with severe angina are at high risk of preangioplasty occlusion and/or myocardial infarction; prompt management of these patients, when considered for PTCA, seems advisable.

Angiography↗

PubMed1986

Tolerance of unusually low mixed venous oxygen saturation. Adaptations in the chronic low cardiac output syndrome.

Introduction of a reliable method for continuous monitoring of mixed venous oxygen saturation has focused attention on the therapeutic and prognostic implications of this value. It is generally agreed that mixed venous oxygen saturation in the 40 to 60 percent range is associated with substantial patient morbidity and mortality if not rapidly corrected. However, several patients with chronic low cardiac output syndrome who have had mixed venous oxygen saturation of less than 40 percent for prolonged periods of time and who have not had decompensation were observed. Three representative patients with these findings are described and mechanisms put forth that may account for the observed relations between mixed venous oxygen saturation and mortality in these and other patients.

Adaptation, Physiological↗

PubMed1986

Should airline pilots be eligible to resume active flight status after coronary bypass surgery?: a CASS registry study.

Medical certification to return to work after coronary bypass surgery in occupations that carry a risk to public safety is controversial, particularly for airline pilots. To address this issue, 10,312 patients from the CASS registry who underwent coronary bypass surgery were studied and 2,326 men with clinical and postoperative characteristics similar to those of the average airline pilot who might apply to renew his license after surgery were selected. The 5 year probability of remaining free of an acute cardiac event, defined as acute coronary insufficiency, myocardial infarction or sudden death, was 0.92 +/- 0.01 (mean +/- SE) for the 1,207 men without previous myocardial infarction and 0.98 +/- 0.01 for the 122 men who never smoked and did not have a history of hypertension. Among the 1,119 men with a previous myocardial infarction, the probability of remaining free of acute cardiac events was 0.91 +/- 0.02 and 0.92 +/- 0.02 when left ventricular contraction score was 5 to 9 and 10 or greater, respectively. In this patient subgroup, mortality rate was similar to that of the age-matched U.S. male population when the left ventricular contraction score was 5 to 9 (4.0% versus 4.3%; p = NS) but significantly worse when the left ventricular contraction score was 10 or greater (7% versus 4.2%; p = 0.05). The data from this CASS registry study are pertinent to the question of operationally unlimited first-class medical certification of carefully selected airline pilots after coronary bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1986

Histopathology after Nd-YAG laser percutaneous transluminal angioplasty of peripheral arteries.

Laser recanalization of occluded femoral or popliteal arteries was performed in 12 patients using a continuous wave neodymium yttrium aluminum garnet (Nd-YAG) laser. The histologic findings of the laser-irradiated arterial segments in two of these patients are reported. The specimens were obtained 2 and 4 weeks after the laser procedure. The laser-irradiated vessel in Patient 1 had been partially recanalized with reduction of the atherosclerotic occlusion from 3 to 1 cm. The lased arterial lumen manifested thermal injury to the inner quarter of the arterial wall with vacuolization and a rim of carbonization occupying 10% of the width of the arterial wall, but without thrombus formation. Histologic examination in Patient 2 revealed no fibrin deposits, atherosclerotic debris or thrombi at the intimal arterial edge. At the crater site, thermal injury was apparent with vacuolization of the intimal fibrous tissue. The histologic sections obtained 4 weeks after the procedure revealed new fibrous intimal tissue without endothelialization in some of the heavily calcified tissue sections. Where the plaques were noncalcified, reendothelialization was noted with only minimal damage to the surrounding tissue. No medial or elastic fiber disruption was seen, and no aneurysmal dilation had occurred. Intimal splitting with a cleft between the tunica media and the intima was noted at the site of previous balloon angioplasty. In conclusion, the follow-up histologic findings 2 and 4 weeks after laser angioplasty in two patients using a specially designed catheter delivery system and cooling blood perfusate revealed thermal injury to the inner quarter of the arterial vessel wall and no evidence of thrombus formation.

Aged↗

PubMed1986

The changing role of the exercise electrocardiogram as a diagnostic and prognostic test for chronic ischemic heart disease.

The exercise electrocardiogram has been the subject of intense research over the last 50 years, as both a diagnostic and prognostic method to assess patients with chronic ischemic heart disease. In 1986, the strengths and limitations of the technique to predict coronary and multivessel disease in clinical patient subsets are understood. The diagnostic accuracy of the test is improved by consideration of Bayesian theory, multivariate models and new non-ST segment criteria. Post-test coronary disease risk estimates are best reported in terms of a conditional probability, rather than statements of "positive" or "negative." The value of exercise testing in prognostic risk stratification is considerably enhanced by recent reports of long-term follow-up data in asymptomatic and symptomatic patients. Powerful prognostic information can be obtained when the clinical, electrocardiographic and physiologic data from the exercise test are used to formulate the post-test risk of a cardiac event, even in patients whose coronary anatomy is known. The changing role of the exercise electrocardiogram as a diagnostic and prognostic test is reviewed, with emphasis on the strengths and limitations of the procedure.

Angina Pectoris↗

PubMed1986

The role of exercise testing in identifying patients with improved survival after coronary artery bypass surgery.

To determine whether exercise testing can identify patients whose survival might be prolonged by coronary artery bypass surgery, the results of bypass surgery were compared with those of medical therapy alone in 5,303 nonrandomized patients from the Coronary Artery Surgery Study registry who underwent exercise testing. Patients in the two treatment groups differed substantially with regard to important baseline variables. Analysis of 32 variables by Cox's regression model for survival revealed an independent beneficial effect of bypass surgery on survival (p less than 0.00001). Patients were then stratified into subsets according to the results of exercise testing. Surgical benefit was greatest in the 789 patients who exhibited at least 1 mm of ST segment depression and who could exercise only into stage 1 or less. Among the 398 patients with three vessel coronary disease showing these characteristics, 7 year survival was 58% for the medical group and 81% for the surgical group (p less than 0.001). There was no difference in survival between the surgical and medical groups among the 1,545 patients without ischemic ST segment depression who were able to exercise into stage 3 or greater. Thus, in patients who demonstrate ischemia on exercise testing and whose exercise capacity is limited, coronary bypass surgery appears to improve survival in comparison with medical therapy alone.

Coronary Artery Bypass↗

PubMed1986

Role of exercise testing in relationship to coronary artery bypass surgery and percutaneous transluminal coronary angioplasty.

Most patients who are considered candidates for coronary angioplasty should have objective evidence of myocardial ischemia confirmed before the procedure, if clinically possible. In patients with progressive unstable angina, for whom exercise testing is inappropriate, the location of transient resting ECG changes should be looked for on the 12-lead ECG. In clinically stable patients with 1-vessel coronary disease, a pre-PTCA exercise test without radionuclides would suffice for most patients. In the initial months after PTCA, persistence or the return of an ischemic response similar to that observed before the procedure would indicate restenosis. Disease progression in other vessels during the year after the PTCA procedure would be uncommon compared to the incidence of restenosis. In all other stable patients, exercise ECG should be combined with thallium-201 scintigraphy to provide a more useful evaluation of angioplasty results. If only a single vessel is dilated, the importance of the remaining coronary disease may be demonstrated and may influence the clinical decision as to whether further intervention is needed. Dilatation of occluded vessels is occasionally attempted in patients with multivessel coronary disease. The incidence of restenosis is slightly greater (40%) in the months after PTCA than in a stenotic nonoccluded vessel. Multilesion dilatation can also be associated with restenosis at more than one site, and the use of thallium scintigraphy may be helpful in assessing which region of the myocardium is ischemic. As dilatation is performed more frequently in patients with multivessel disease, coronary angiography will remain the 'gold standard' to answer questions about recurrence or progression of the disease, and against which to compare results of noninvasive tests. All exercise tests should be performed without cardioactive medication if possible, and the test should be a sign- or symptom-limited test. The elective exercise test in an asymptomatic individual after PTCA should be performed between 1 and 2 weeks to serve as a baseline for future follow-up. In patients who develop restenosis, symptomatic status will often suggest a PTCA failure. In asymptomatic patients or those with atypical symptoms, the exercise thallium study will often be useful.

Angioplasty, Balloon↗

PubMed1986

The role of coronary bypass surgery for 'left main equivalent' coronary disease: the Coronary Artery Surgery Study registry.

Combined proximal left anterior descending and proximal left circumflex, or "left main equivalent" (LMEQ), disease defines a prognostic angiographic high-risk patient population. We assessed the effect of coronary bypass surgery compared with medical therapy in 903 patients with LMEQ disease by stratified life table and Cox regression analysis. The 5 year survival rates of the 639 and 264 patients who received surgical vs medical therapy was 85% vs 55%, respectively (p less than .001). Analysis of patient subsets stratified by age, angina class, right coronary disease, and ejection fraction revealed a significant survival benefit for surgically treated patients in most strata. Cox regression analysis revealed improved survival for surgically treated patients after adjustment for important baseline variables known to influence prognosis. Surgically treated patients had significantly less angina and need for antianginal drugs compared with the medically treated group. When the Coronary Artery Surgery Study randomized and randomizable LMEQ patients were analyzed, coronary bypass surgery improved 5 year survival when preoperative ejection fraction was under 0.50 but not when ejection fraction was 0.50 or higher. Thus coronary bypass surgery prolongs and improves quality of life (as defined by angina status and need for antianginal drugs) in most patients with LMEQ disease but does not appear to improve 5 year survival in a small subset of LMEQ patients who are asymptomatic after myocardial infarction or who have mild chronic stable angina and are under age 65 with well-preserved left ventricular function.

Aged↗

PubMed1985

Comparative diagnostic value of exercise polarcardiography and 14-lead electrocardiography in the detection of coronary artery disease.

Early postexercise polarcardiographic (PCG) changes in the ST segment vector, as reflected in the variable MS X theta, are reported to clearly distinguish normal subjects from those with myocardial ischemia. We prospectively assessed the value of this test in detecting coronary artery disease (CAD) during treadmill exercise in 178 patients within 1 week of diagnostic coronary angiography. The average postexercise MS X theta was 16.9 +/- 9.7 mV degrees in patients with CAD, whereas it was 16.2 +/- 10.2 mV degrees in patients with CAD (p = NS). The optimal ratio of sensitivity to specificity, using different normal-abnormal cutoff values, was 57% and 56%, respectively, for a delineating MS X theta value of 12. The sensitivity and specificity of a simultaneously recorded 14-lead ECG using the criterion of exercise-induced horizontal downsloping ST segment depression greater than or equal to 0.1 mV, was 71% and 78%, respectively. The PCG results were not improved by analyzing MS X theta during exercise, or by analyzing the difference in MS X theta between rest and exercise or rest and postexercise. The sensitivity of the PCG for multivessel or left anterior descending CAD was higher than for less severe forms of CAD, but was significantly less sensitive than the 14-lead exercise ECG (70% versus 84%; p = 0.02; and 62% versus 75%; p = 0.05, respectively). Thus, exercise polarcardiography, as employed in the present study, does not improve the diagnostic content of the 14-lead exercise ECG. Contrary to previous reports, there is no clear separation of normal from abnormal MS X theta values when a prospective series of patients is tested.

Coronary Disease↗

PubMed1985

A logistic regression analysis of multiple noninvasive tests for the prediction of the presence and extent of coronary artery disease in men.

The incremental diagnostic yield of clinical data, exercise ECG, stress thallium scintigraphy, and cardiac fluoroscopy to predict coronary and multivessel disease was assessed in 171 symptomatic men by means of multiple logistic regression analyses. When clinical variables alone were analyzed, chest pain type and age were predictive of coronary disease, whereas chest pain type, age, a family history of premature coronary disease before age 55 years, and abnormal ST-T wave changes on the rest ECG were predictive of multivessel disease. The percentage of patients correctly classified by cardiac fluoroscopy (presence or absence of coronary artery calcification), exercise ECG, and thallium scintigraphy was 9%, 25%, and 50%, respectively, greater than for clinical variables, when the presence or absence of coronary disease was the outcome, and 13%, 25%, and 29%, respectively, when multivessel disease was studied; 5% of patients were misclassified. When the 37 clinical and noninvasive test variables were analyzed jointly, the most significant variable predictive of coronary disease was an abnormal thallium scan and for multivessel disease, the amount of exercise performed. The data from this study provide a quantitative model and confirm previous reports that optimal diagnostic efficacy is obtained when noninvasive tests are ordered sequentially. In symptomatic men, cardiac fluoroscopy is a relatively ineffective test when compared to exercise ECG and thallium scintigraphy.

Adult↗

PubMed1985

A dose-ranging, placebo-controlled, double-blind trial of nisoldipine in effort angina: duration and extent of antianginal effects.

Maximal treadmill exercise testing at 1, 3 and 8 hours was used to assess the onset, duration and antianginal efficacy of the dihydropyridine slow channel calcium-blocking agent, nisoldipine, in an oral dose range of 5, 10 and 20 mg. A double-blind, randomized, placebo-controlled design was used involving 12 patients with stable effort angina. Exercise tolerance was significantly increased 3 hours after each dose, when the maximal beneficial effect occurred. The improvement was observed as early as 1 hour after the 10 and 20 mg dose, and persisted for 8 hours after the 20 mg dose. At 3 hours, the onset of an exercise-induced ST segment depression of 0.1 mV or greater was increased by 62 (p less than 0.05), 75 (p less than 0.01) and 117 seconds (p less than 0.01) with the 5, 10 and 20 mg dose of nisoldipine, respectively, compared with placebo. Similarly, time to onset of angina was significantly increased. The sum of exercise-induced ST segment depression at peak exercise was significantly decreased (p less than 0.05) from 8.7 +/- 2.3 to 6.7 +/- 1.8 and 6.4 +/- 2.0 mm, respectively, after the 10 and 20 mg dose of nisoldipine. The rate-pressure product was significantly greater with nisoldipine than with placebo at the onset of ischemia and at peak exercise (22.8 +/- 1.1 versus 20 +/- 1.4 X 10(3) U for the 20 mg dose; p less than 0.01). Thus, nisoldipine is an effective antianginal agent with a rapid onset of action that improves exercise tolerance, increases angina threshold and persists for at least 8 hours after oral dosing.

Aged↗

PubMed1985

Immediate and short-term benefit of multilesion coronary angioplasty: influence of degree of revascularization.

The safety and short-term therapeutic benefit of multilesion percutaneous transluminal coronary angioplasty was assessed in 135 patients, 66 of whom had a minimum of 6 months of follow-up study. Primary success, defined as successful dilation of the most critical lesion or all lesions attempted without major in-hospital complications was obtained in 117 (87%) of the 135 patients. Cardiac complications associated with the procedure were uncommon; prolonged angina occurred in 5% and myocardial infarction in 3%; emergency coronary bypass surgery was performed in 4% of the patients. There were no deaths. Complete revascularization was achieved in 46% of the 117 patients with a primary success. Of the 66 patients eligible for 6 month follow-up, 80% had an uncomplicated course and required no further procedures. Clinical improvement by at least one angina functional class was observed in 90% of the patients. Cardiac events such as the need for a second revascularization procedure were significantly more common in patients who had incomplete versus complete revascularization (35 versus 9%; p = 0.018). Repeat coronary angiography performed an average of 5 months after angioplasty revealed restenosis in 18 of 22 symptomatic patients and 3 of 9 asymptomatic patients. Restenosis occurred at the site of a single dilation in 12 patients, at two sites in 8 patients and at three sites in 1 patient. Thus, multilesion coronary angioplasty is an important therapeutic option for selected patients with multivessel disease and can be performed with relatively low risk. Improvement in angina status can be expected even in patients who have incomplete revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Exercise testing in the Coronary Artery Surgery Study randomized population.

Exercise electrocardiographic stress testing was performed in 81% of the 780 patients randomized in the Coronary Artery Surgery Study at entry. The cumulative survival at the end of 7 year follow-up was 90% for those assigned to surgical treatment and 88% for those assigned to medical therapy (p = NS). These survival rates did not differ significantly from either those of the entire randomized cohort or those of the 149 patients who did not have a qualifying exercise test at baseline. No differences in important baseline characteristics existed between those who were exercised and not exercised at entry. Stratification of patients according to the degree of ST segment depression (less than 1 mm, greater than or equal to 1 mm, greater than 2 mm) and final exercise stage achieved during a Bruce protocol treadmill test (final stage less than or equal to 1, stage 2 and greater than or equal to stage 3) failed to show any significant differences in 7 year survival rates between medically and surgically assigned patients. Additionally no differences in survival were noted within either the medical or surgical groups regardless of the degree of ST segment depression or the final stage achieved. The presence of exercise-induced angina, however, identified patients who had a survival advantage if assigned to surgical therapy, with a 7 year survival rate of 94% compared with 87% for medically assigned patients (p = .007).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗