Gender differences in use of stress testing and coronary heart disease mortality: a population-based study in Olmsted County, Minnesota

OBJECTIVES

We sought to examine the utilization of exercise stress testing in relation to age and gender in a population-based setting.

BACKGROUND

The utilization of noninvasive procedures has been shown to be associated with the subsequent use of invasive procedures. Yet, there are no population-based data on the utilization of stress testing; in particular, although gender differences in the use of invasive procedures have been reported, the use of noninvasive procedures has not been examined in relation to gender.

METHODS

In Olmsted County, Minnesota, passive surveillance of the medical care of the community is provided through the Rochester Epidemiology Project. A population-based cohort of Olmsted County residents undergoing exercise tests was identified. The medical records of residents with prevalent and incident exercise tests in 1987 and 1988 were reviewed. For persons with an initial test (incidence cohort), data on clinical presentation, test indications and results were abstracted. Stress test utilization rates were calculated, and crude rates were directly adjusted to the age distribution of the 1980 U.S. population. To help interpret patterns of use at the population level, coronary heart disease mortality rates (International Classification of Diseases, 9th revision, codes 410 to 414) were calculated (crude and directly adjusted to the overall age distribution of the 1980 U.S. population) and used as an indicator of coronary disease burden.

RESULTS

A total of 2,624 tests were performed. The crude utilization rate (per 100,000) was 1,888 for men and 703 for women (rate ratio for men over women 2.7, 95% confidence interval [CI] 2.5 to 2.9); it remained significantly higher in men across all age strata. The crude incidence rate (per 100,000) of initial stress tests was 1,112 for men and 517 for women (rate ratio 2.2, 95% CI 1.9 to 2.4). For both men and women, the incidence increased with age; however, incidence remained lower in women in all age strata. At the time that they underwent an initial test, women were more symptomatic and had poorer exercise performance than men. The rate ratio of men over women for coronary heart disease mortality was 1.1 (95% CI 0.9 to 1.2). The age-adjusted rate ratios for stress test utilization were 2.8 (95% CI 2.5 to 3.0), and that for coronary heart disease mortality was 1.9 (95% CI 1.7 to 2.2).

CONCLUSIONS

These population-based data show that during the study period, the utilization of stress testing in Olmsted County was lower in women than in men. Women in the incidence cohort were older and more symptomatic and had poorer exercise performance than men. Such differences should be considered when examining the utilization of subsequent invasive procedures according to gender.

Safety of dobutamine stress echocardiography supervised by registered nurse sonographers

Dobutamine stress echocardiography (DSE) is widely used for the diagnosis and evaluation of coronary artery disease. Studies examining the safety of this technique typically have involved DSE supervised by physicians. At the Mayo Clinic, experienced registered nurse (RN) sonographers were trained to perform DSE under the direct supervision of a physician. To prove that the safety of DSE was not compromised with the change in supervision, we examined data from 1035 consecutive outpatient studies: 516 patients were monitored by cardiologists or cardiology fellows (group 1) and 519 were monitored by trained RN sonographers (group 2). Risk factors, history of coronary artery disease, stress parameters, and complication rates were similar in both groups. In group 1, one patient experienced sustained ventricular tachycardia requiring treatment. In group 2, one patient experienced ventricular fibrillation during recovery and was successfully resuscitated. Outpatient DSE is safe when supervised by RN sonographers.

Role of dobutamine stress echocardiography in predicting outcome in 860 patients with known or suspected coronary artery disease

BACKGROUND

Increasingly, dobutamine stress echocardiography has been used for detection of coronary artery disease. Less information exists regarding the incremental prognostic value of the test, including semiquantitative wall scoring, compared with clinical and rest echocardiographic variables.

METHODS AND RESULTS

Follow-up information was obtained from 860 patients who underwent dobutamine stress echocardiography over a 2-year period. To determine the value of dobutamine stress echocardiography in predicting cardiac events, including cardiac death and myocardial infarction, clinical and rest and stress echocardiographic data were considered in a stepwise Cox multivariate regression model. During follow-up of up to 52 months, 72 patients underwent coronary revascularization before any cardiac event and were censored. Eighty-six patients had cardiac events, including nonfatal myocardial infarction in 36 and cardiac death in 50. In a multivariate model, a history of congestive heart failure, the percentage of abnormal segments at peak stress, and an abnormal left ventricular end-systolic volume response to stress were independent predictors of cardiac events. The model that best predicted subsequent cardiac events included clinical and stress echocardiographic data.

CONCLUSIONS

Dobutamine stress echocardiography with semiquantitative segmental wall scoring provides important incremental information in predicting subsequent cardiac events.

Stress echocardiography: recommendations for performance and interpretation of stress echocardiography. Stress Echocardiography Task Force of the Nomenclature and Standards Committee of the American Society of Echocardiography

Cardiovascular stress testing remains the mainstay of provocative evaluation for patients with known or suspected coronary artery disease. Stress echocardiography has become a valuable means of cardiovascular stress testing. It plays a crucial role in the initial detection of coronary disease, in determining prognosis, and in therapeutic decision making. The purpose of this document is to outline the recommended methodology for stress echocardiography with respect to personnel and equipment as well as the clinical use of this recently developed technique. Specific limitations will also be discussed.

Outcome after normal exercise echocardiography and predictors of subsequent cardiac events: follow-up of 1,325 patients

OBJECTIVES

This study sought to examine the outcome of a large group of patients after normal exercise echocardiography and to identify potential predictors of subsequent cardiac events.

BACKGROUND

Earlier studies suggested that prognosis after normal exercise echocardiography is favorable, with a low subsequent cardiac event rate. These studies involved a small number of patients and did not have sufficient statistical power to stratify risk.

METHODS

The outcomes of 1,325 patients who had normal exercise echocardiograms were examined. End points were overall and cardiac event-free survival. Cardiac events were defined as cardiac death, nonfatal myocardial infarction and coronary revascularization. Patient characteristics were analyzed in relation to time to first cardiac event in a univariate and multivariate manner to determine which, if any, were associated with an increased hazard of subsequent cardiac events.

RESULTS

Overall survival of the study group was significantly better than that of an age- and gender-matched group obtained from life tables (p < 0.0001). The cardiac event-free survival rates at 1, 2 and 3 years were 99.2%, 97.8% and 97.4%, respectively. The cardiac event rate per person-year of follow-up was 0.9%. Subgroups with an intermediate or high pretest probability of having coronary artery disease also had low cardiac event rates. Multivariate predictors of subsequent cardiac events were angina during treadmill exercise testing (risk ratio [RR] 4.1, 95% confidence interval [CI] 1.5 to 11.0), low work load (defined as < 7 metabolic equivalents [METs] for men and < 5 METs for women; RR 3.2, 95% CI 1.4 to 7.6), echocardiographic left ventricular hypertrophy (RR 2.6, 95% CI 1.1 to 6.3) and advancing age (RR 1.04/year, 95% CI 1.0 to 1.1).

CONCLUSIONS

The outcome after normal exercise echocardiography is excellent. Subgroups with an intermediate or high pretest probability of having coronary artery disease also have a favorable prognosis after a normal exercise echocardiogram. Characteristics predictive of subsequent cardiac events (i.e., patient age, work load, angina during exercise testing and echocardiographic left ventricular hypertrophy) should be considered in the clinical interpretation of a normal exercise echocardiogram.

Hypertensive response during dobutamine stress echocardiography

Among 3,129 dobutamine stress echocardiographic studies, a hypertensive response, defined as systolic blood pressure (BP) > or = 220 mm Hg and/or diastolic BP > or = 110 mm Hg, occurred in 30 patients (1%). Patients with this response more often had a history of hypertension and had higher resting systolic and diastolic BP before dobutamine infusion.

Stress echocardiography in the evaluation of chest pain and accuracy in the diagnosis of coronary artery disease

Stress echocardiography has emerged as a valuable technique for the noninvasive detection of coronary artery disease. The accuracy of exercise echocardiography, using treadmill or bicycle stress, and of pharmacological stress echocardiography, using dobutamine or vasodilators, has been verified in large numbers of patients. In the detection of coronary artery disease, its accuracy is superior to that of the exercise electrocardiogram and appears comparable to the accuracy of SPECT perfusion imaging. In addition, stress echocardiography is useful in the localization and quantitation of coronary artery disease. Unique to stress echocardiography is the potential to detect other forms of heart disease that may be associated with chest pain. These characteristics support its use in the evaluation of the patient with chest pain.

Paradoxical sinus deceleration during dobutamine stress echocardiography: description and angiographic correlation

OBJECTIVES

This report characterizes the paradoxical sinus deceleration occasionally observed during dobutamine stress testing and determines its relation to myocardial ischemia.

BACKGROUND

Dobutamine stress echocardiography is widely accepted as a noninvasive tool for evaluating coronary artery disease. With infusion of dobutamine, there is typically a dose-dependent increase in heart rate. However, in some patients, a paradoxical decrease in heart rate has been observed during high dose dobutamine infusion.

METHODS

In 181 consecutive patients undergoing both dobutamine stress echocardiography and coronary angiography, electrocardiographic (ECG) data collected during dobutamine infusion were reviewed to identify patients with a decrease in heart rate. The clinical, stress echocardiographic, hemodynamic and angiographic correlates of patients with a decrease in heart rate were reviewed.

RESULTS

A decrease in heart rate ranging from 7 to 64 beats/min occurred during high dose dobutamine infusion in 14 patients (8%, 95% confidence interval [CI] 6% to 10%), including 3 in whom a junctional rhythm developed. The decrease was sudden in five patients (36%, 95% CI 13% to 65%) and gradual in nine (64%, 95% CI 35% to 87%). A decrease in blood pressure (12 patients [86%], 95% CI 57% to 98%) with simultaneous chest pain (7 patients [50%], 95% CI 23% to 77%) and nausea (5 patients [36%], 95% CI 13% to 65%) was common. Significant coronary artery disease (> or = 50% diameter stenosis) was present in 8 (57%) of 14 patients (95% CI 29% to 82%). Two patients (14%, 95% CI 2% to 43%) had no clinical, ECG or echocardiographic evidence of ischemia and no significant coronary artery disease by angiography. There was no increased incidence of right coronary artery stenosis in patients with paradoxical sinus deceleration.

CONCLUSIONS

Paradoxical sinus deceleration occurs in 8% of patients during dobutamine stress testing. Although most often observed in patients with coronary artery disease, it can occur in the absence of ischemia and coronary artery disease, and in some patients may be due to a vasodepressor reflex.

Is review of videotape necessary after review of digitized cine-loop images in stress echocardiography? A prospective study in 306 patients

The interpretation of stress echocardiography has been made easier by the comparison of digitized prestress and poststress frame-grabbed images (cine-loops), each representing a portion of a single cardiac cycle. Often, review of these digitized images is substituted for review of the complete videotape record of the examination. An alternative is to review both the digitized images as well as the videotape record of the rest and stress images. To date, there has been insufficient documentation of whether these options (cine-loop images alone versus cine-loop images plus videotape) provide comparable or additive information. Therefore, we prospectively evaluated information obtained from review of cine-loop images versus combined review of cine-loop images and videotape records in 306 consecutive patients undergoing treadmill (213 patients, 70%) or dobutamine (93 patients, 30%) stress echocardiography. An experienced echocardiologist first reviewed the cine-loop images and scored the wall motion in 16 segments at rest and with stress. Next, the complete videotape record was reviewed with repeated wall motion scoring. A questionnaire comparing cine-loop and videotape images was completed at the end of each review. Digitization of images was technically inadequate in 14 patients (4%). In 116 (40%) of the other 292 patients, the regional wall motion assessment, after relying solely on cine-loop images, was modified with subsequent videotape review. In 40 patients (14%), these modifications resulted in a change in the final impression regarding whether the study result was normal or abnormal. In a multivariate analysis, age, gender, and type of stress echocardiography had no significant influence on discordance of the cine-loop image and combined cine-loop and video information. Stepwise logistic regression analysis identified poorer image quality (p < 0.0001) and regional wall motion abnormalities (p < 0.0001) as predictors of discordance between cine-loop and combined review. We conclude that relying solely on digitized cine-loop images representing a single cardiac cycle is not optimal, especially if the quality of the digitized images is suboptimal and if regional wall motion abnormalities are present. Thus we recommend a combined review of both cine-loop images and videotape images in the interpretation of stress echocardiography.

Sex and test verification bias. Impact on the diagnostic value of exercise echocardiography

BACKGROUND

The use of exercise echocardiography for the diagnosis of coronary artery disease (CAD) has been validated in pilot studies but is not documented in clinical practice and in women comparatively with men. The objectives of this study were to determine the effects of sex and of test verification bias on the diagnostic performance of exercise echocardiography.

METHODS AND RESULTS

Three thousand six hundred seventy-nine consecutive patients (1714 women, 1965 men) who underwent an exercise echocardiographic study were studied; the observed sensitivity, specificity, and correct classification rate were calculated among 340 patients (244 men, 96 women) who underwent angiography; to study the effect of test verification bias, sensitivity and specificity were estimated for all patients who underwent exercise echocardiography including those not referred to angiography. In the angiographic group, the prevalence of CAD was 60% in women and 80% in men. The observed sensitivity and specificity of exercise echocardiography was 78% and 44% in men and 79% and 37% in women. After adjustment for test verification bias, the estimated sensitivity was lower in women (32% versus 42% in men), whereas specificity was similar in both sexes. The positive predictive value was lower in women (66%) compared with men (84%).

CONCLUSIONS

In clinical practice, test verification bias results in a lower observed specificity and a higher sensitivity of exercise echocardiography. In women, positive predictive value and adjusted sensitivity are lower compared with that in men.

Atropine augmentation in dobutamine stress echocardiography: role and incremental value in a clinical practice setting

OBJECTIVES

This study sought to evaluate the role and incremental value of atropine in a large patient group undergoing dobutamine stress echocardiography.

BACKGROUND

The use of atropine to potentiate dobutamine stress is not standard practice. Although the utility of atropine has been described, data on its incremental value remain limited and do not exist for a routine clinical practice setting.

METHODS

Dobutamine stress echocardiography was performed in 1,171 patients with use of a standard protocol. Atropine (maximal dose 2.0 mg) was given to 299 patients (26%) who did not attain target heart rate. Coronary angiography was performed in 183 patients (46 received atropine), 148 of whom were found to have significant coronary artery disease (> or = 70% diameter stenosis in a major epicardial vessel, > or = 50% stenosis for left main coronary artery disease). All tests were reviewed independently by experienced observers.

RESULTS

There were no major adverse events. Patients receiving atropine had a lower rest heart rate (65 vs. 74 beats/min, p < 0.0001) and more often received beta-adrenergic blocking agents (49% vs. 14%, p < 0.0001). Of 444 patients in whom stress-induced ischemia developed, 70 (16%) required atropine before ischemia became evident. Sensitivity for detection of significant coronary artery disease was 90% with dobutamine alone and 95% after the addition of atropine. In 66 patients with normal wall motion at rest, test sensitivity was 65% before and 84% after atropine was given. Atropine use did not compromise test specificity. New diagnostic information was obtained in 20 (50%) of 40 patients with angiographic coronary artery disease given atropine. Proportionately more patients with single-vessel disease required atropine before an ischemic response was observed; this effect appeared related to the higher ischemic threshold in these patients.

CONCLUSIONS

Augmentation of heart rate had a modest influence on the overall diagnostic sensitivity of dobutamine stress echocardiography in our study cohort. However, it was particularly helpful in patients receiving beta-blockers and those with milder coronary disease. Despite the use of > or = 1 mg of atropine in some patients, this incremental value was not achieved at the expense of safety.

Comparison of ischemic response during exercise and dobutamine echocardiography in patients with left main coronary artery disease

OBJECTIVES

This study sought to compare manifestations of myocardial ischemia evoked by exercise and dobutamine echocardiography in patients with left main coronary artery disease.

BACKGROUND

During exercise testing, left ventricular cavity dilation, marked ST segment depression and blood pressure decrease indicate severe coronary artery disease. Whether these signs are comparably evoked by dobutamine echocardiography has not been described.

METHODS

Fifty-four patients who underwent stress echocardiography (36 exercise, 18 dobutamine) and coronary angiography showing > or = 50% left main stenosis were analyzed. Electrocardiographic and blood pressure changes, symptoms, wall motion score indexes and sensitivity for coronary artery disease were compared. In 47 patients, the left ventricular endocardium was traced to quantify volumes and ejection fraction.

RESULTS

Stress-induced regional wall motion abnormalities developed in 91% of patients; this was not different on exercise (89%) or dobutamine echocardiography (94%). Rate-pressure product and wall motion score index, similar at rest, tended to be higher after exercise than after dobutamine stress (p = 0.07 and p = 0.05, respectively). ST segment depression > or = 1 mm was more common with exercise (p = 0.005). Ejection fraction and end-systolic and end-diastolic volume indexes were comparable at rest in both groups. With exercise, ejection fraction decreased in 87% of patients, and end-systolic and end-diastolic volume indexes increased in 80%. In contrast, with dobutamine, decreased ejection fraction and increased volume indexes were infrequent. Ejection fraction was lower ([mean +/- SD] 45 +/- 19% vs. 54 +/- 12%, p = 0.007) and end-diastolic (69 +/- 26 vs. 50 +/- 17 ml/m2, p =0.02) and end-systolic (39 +/- 20 vs. 24 +/- 13 ml/m2, p = 0.02) volume indexes were higher after exercise than after dobutamine stress.

CONCLUSIONS

On the basis of changes in regional wall motion both dobutamine and exercise echocardiography have a comparable high sensitivity in diagnosing myocardial ischemia in left main coronary artery disease. However, conventional signs of severe myocardial ischemia, including left ventricular cavity dilation and marked ST segment depression, occur more often with exercise than with dobutamine echocardiography.

Safety of performing dobutamine stress echocardiography in patients with abdominal aortic aneurysm > or = 4 cm in diameter

Dobutamine stress echocardiography is frequently used for preoperative assessment of cardiac risk before major vascular surgical procedures. Dobutamine increases myocardial contractility, heart rate, and rate of increase of left ventricular pressure and has a variable effect on blood pressure. These effects could potentially increase the likelihood of rupture of a vascular aneurysm. The safety of performing dobutamine stress echocardiography in patients with vascular aneurysms has not been adequately addressed. Of 1,968 consecutive patients who underwent dobutamine stress echocardiography at our institution, 98 patients with abdominal aortic aneurysms > or = 4 cm in diameter were identified. Records were reviewed to determine whether there was any evidence of aneurysm rupture or adverse vascular events as a result of the stress test. There was no case of aneurysm rupture or hemodynamic instability precipitated by dobutamine stress echocardiography. In addition, dobutamine stress echocardiography that was negative for ischemia identified patients at very low risk of perioperative cardiac events. The positive predictive value of ischemia during dobutamine echocardiography was 29%. Dobutamine stress echocardiography may be performed safely in patients with aortic aneurysms. Precipitation of an aneurysmal complication, including rupture, by the test is unlikely. In addition, preoperative dobutamine stress echocardiography can identify patients at very low risk of perioperative cardiac events.

Normal stroke volume and cardiac output response during dobutamine stress echocardiography in subjects without left ventricular wall motion abnormalities

Dobutamine stress echocardiography has become widely utilized for evaluation of coronary artery disease, but the expected responses of stroke volume and cardiac output to the high doses of dobutamine administered in these studies are not known. To determine these responses, stroke volume and cardiac output were measured with 2-dimensional Doppler echocardiography at each stage of dobutamine stress echocardiography and after administration of atropine in 47 patients without resting or inducible wall motion abnormalities. Heart rate increased significantly at each stage of dobutamine infusion and after atropine. Mean blood pressure decreased at the 5 micrograms/kg/min dose, then showed little change. Stroke volume increased 27 +/- 18% from baseline, with significant increases occurring at both the 5 and 10 micrograms/kg/min doses (p < 0.00001). With higher doses of dobutamine, stroke volume tended to plateau or decrease. Mean changes in stroke volume were not significant between the doses of 10, 20, and 30 micrograms/kg/min. The mean change in stroke volume from the 30 to the 40 micrograms/kg/min dose was a significant decrease of 6.3% (p = 0.004); the decrease from the 40 micrograms/kg/min dose to atropine approached statistical significance (p = 0.06). Cardiac output increased throughout dobutamine infusion. Stroke volume during dobutamine stress echocardiography is commonly maximum at a dose of 20 micrograms/kg/min and tends to decline at higher infusion rates. At higher doses, increases in cardiac output are mediated primarily by increases in heart rate.

Assessment of myocardial viability in chronic left ventricular dysfunction

Differentiation of infarcted from viable myocardium is of critical clinical importance in patients with severely impaired left ventricular function. While positron emission tomography is considered the "gold-standard" modality for detection of viable myocardium, expense has limited its more widespread use. Therefore, many centers employ surrogate tests for metabolic viability. In several recent studies, low-dose dobutamine echocardiography has been useful in predicting recovery of poorly contractile myocardium. Myocardial contrast echocardiography is a promising new technique which may predict viability by defining areas of preserved microvascular integrity. The clinical role of these diagnostic modalities in the setting of depressed ventricular function is as yet uncertain. Clarification of the utility of these tests should allow more judicious selection of patients who would derive the greatest survival benefit from revascularization procedures.

Outcome of cardiac surgery for carcinoid heart disease

OBJECTIVES

The hypothesis was that cardiac surgery for symptomatic carcinoid heart disease in conjunction with adjunctive therapy could improve the long-term outlook of patients with carcinoid heart disease.

BACKGROUND

Patients with carcinoid heart disease have a dismal prognosis; most die of progressive right heart failure within 1 year after onset of symptoms. Improved therapies for the systemic manifestations of the carcinoid syndrome have resulted in symptomatic improvement and prolonged survival in patients without heart disease.

METHODS

Twenty-six patients with symptomatic carcinoid heart disease underwent valvular surgery. Preoperative clinical, laboratory, Doppler echocardiographic and hemodynamic factors were evaluated. The survival of the surgical group was compared with that of a control group of 40 medically treated patients.

RESULTS

There were nine perioperative deaths (35%), primarily from postoperative bleeding and right ventricular failure. Of the 17 surgical survivors, 8 were alive at a mean of 28 months of follow-up. The postoperative functional class of the eight surviving patients was substantially improved. Late deaths were primarily due to hepatic dysfunction caused by metastatic disease. The only predictor of operative mortality (p = 0.03) was low voltage on preoperative electrocardiography (limb lead voltage < or = 5 mm). Predictors of late survival included a lower preoperative somatostatin requirement and a lower preoperative urinary 5-hydroxy-indoleacetic acid level. There was a trend toward increased survival for the surgical group compared with the control group.

CONCLUSIONS

Because new therapies have improved survival in patients with the malignant carcinoid syndrome, cardiac involvement has become a major cause of morbidity and mortality. Valve surgery is the only definitive treatment. Although cardiac surgery carries a high perioperative mortality, marked symptomatic improvement occurs in survivors. Surgical intervention should therefore be considered when cardiac symptoms become severe.

Stress echocardiography. Part I. Exercise echocardiography: techniques, implementation, clinical applications, and correlations

OBJECTIVE

To describe the techniques and applications of exercise echocardiography.

DESIGN

We review pertinent experimental and clinical studies from the literature and present our experience with the first 2,000 patients who underwent exercise echocardiography in our laboratory.

MATERIAL AND METHODS

The indications for and contraindications to exercise echocardiography and the advantages, limitations, and accuracy of this procedure in comparison with other techniques for detecting coronary artery disease are discussed.

RESULTS

Exercise echocardiography is increasingly used for the noninvasive evaluation of coronary artery disease because, in addition to its diagnostic capabilities, it offers attractive features such as portability, versatility, rapid availability of results, and relatively low cost. For accurate interpretation of the results, the workload achieved and the time between completion of exercise and image acquisition must be considered. The major limitation of exercise echocardiography is the high degree of operator dependence. For accurate interpretation of regional wall motion abnormalities and recognition of ischemic changes, specific training and extensive experience are necessary.

CONCLUSION

Although exercise echocardiography has only relatively recently become a widely used technique, it has proved to have considerable accuracy in the diagnosis of coronary artery disease (mean sensitivity, 84%; mean specificity, 87%). In high-volume laboratories, feasibility studies have shown success rates between 90 and 99%; thus far, reproducibility has been satisfactory. Other applications of exercise echocardiography being studied are follow-up monitoring after revascularization, determination of prognosis, and assessment of valvular heart disease.

Stress echocardiography. Part II. Dobutamine stress echocardiography: techniques, implementation, clinical applications, and correlations

OBJECTIVE

To describe the rationale, methods, and clinical applications for dobutamine stress echocardiography.

DESIGN

We review our experience with the first 1,000 Mayo Clinic patients who underwent this procedure and discuss studies from the literature that have assessed the accuracy of dobutamine stress echocardiography in determining the presence and extent of coronary artery disease.

MATERIAL AND METHODS

The Mayo protocol for dobutamine stress echocardiography is presented, and the indications for use of this test and comparisons of sensitivity and specificity with other tests are summarized.

RESULTS

Although exercise stress testing is the usual noninvasive method for the detection and assessment of coronary artery disease, a substantial number of patients are unable to perform adequate exercise because of physical limitations. In these patients, dobutamine stress echocardiography has emerged as a feasible, safe, and accurate method for the evaluation of coronary artery disease. The test has been proved to be valuable in the noninvasive diagnosis of coronary artery disease and to have an accuracy comparable to that of tomographic perfusion imaging. Other indications for dobutamine stress echocardiography include risk stratification before noncardiac surgical procedures, risk stratification after myocardial infarction, and identification of viable myocardium in patients with left ventricular dysfunction.

CONCLUSION

Dobutamine stress echocardiography is an accurate, safe, cost-effective, and portable procedure for the noninvasive diagnosis of coronary artery disease and for the preoperative assessment of patients with such disease, especially those who are unable to perform adequate exercise tests.

Identification of multivessel coronary artery disease by exercise echocardiography

OBJECTIVES

This study examined the ability of exercise echocardiography to identify multivessel coronary artery disease and ascertain its incremental value when combined with clinical and exercise test variables.

BACKGROUND

Although exercise echocardiography has been shown to be accurate for the detection of coronary artery disease, little is known about its utility for identifying multivessel involvement, and its incremental value when combined with clinical and exercise test variables has not been studied.

METHODS

One hundred fifty consecutive patients were selected on the basis of having had an exercise echocardiographic and a coronary angiographic study within 6 months without any revascularization procedure. Significant coronary artery disease (> or = 50% diameter stenosis in any major coronary artery) was present in 117 patients, and multivessel (two- or three-vessel) disease was present in 90 patients. The exercise echocardiographic studies were reviewed by an experienced observer unaware of the results of the coronary angiogram.

RESULTS

The overall sensitivity and specificity of exercise echocardiography for the identification of multivessel disease were 73% and 70%, respectively. A stepwise logistic regression analysis identified the number of abnormal regions on the postexercise images as the strongest independent predictor of multivessel disease; also significant were a history of myocardial infarction and ST segment depression of at least 2 mm on the peak exercise electrocardiogram.

CONCLUSIONS

Exercise echocardiography adds independent and incremental information to clinical and exercise test variables for identifying multivessel coronary artery disease.

Carcinoid heart disease. Clinical and echocardiographic spectrum in 74 patients

BACKGROUND

The carcinoid syndrome is a rare cause of acquired valvular heart disease. Although the typical echocardiographic features of carcinoid heart disease are well recognized, this large series provides new information about unusual manifestations of the disease as well as the role of Doppler echocardiography.

METHODS AND RESULTS

Between 1980 and 1989, 132 patients with carcinoid syndrome underwent echocardiographic study. The echocardiographic, Doppler, and clinical features of the 74 patients (56%) with echocardiographic evidence of carcinoid heart disease are described. Among these patients, 97% had shortened, thickened tricuspid leaflets. Tricuspid regurgitation was present in all 69 patients with carcinoid heart disease who underwent Doppler examination, and it was of moderate or severe degree in 62 patients (90%). Severe tricuspid regurgitation was characterized by a dagger-shaped Doppler spectral profile with an early peak pressure and rapid decline. The pressure half-time was prolonged (mean, 116 msec), which is consistent with associated tricuspid stenosis. The pulmonary valve appeared thickened, retracted, and immobile in 36 patients (49%) and was diminutive to the extent of not being visualized in an additional 29 patients (39%). Among the 47 patients who underwent Doppler evaluation of the pulmonary valve, regurgitation was present in 81%, and stenosis was present in 53%. Left-sided valvular involvement was present in five patients (7%), four of whom had patent foramen ovale or carcinoid tumor involving the lung. Previously undescribed myocardial metastases were present in three patients (4%) and were confirmed by biopsy in each case. Small pericardial effusions were present in 10 patients (14%). Patients with and without echocardiographic evidence of carcinoid heart disease did not differ with regard to sex, age, location of the primary tumor, duration of diagnosis, or duration of symptoms of carcinoid syndrome. However, the mean pretreatment level of urinary 5-hydroxyindoleacetic acid was higher in patients with carcinoid heart disease than in patients without carcinoid heart disease (270 versus 131 mg/24 hrs, p < 0.001). The symptom of dyspnea was more prevalent among patients with carcinoid heart disease than in patients without the disease (54% versus 27%, p = 0.003); as expected, heart murmurs were also noted more frequently in patients with disease (92% versus 43%, p < 0.0001). Treatment regimens and response to therapy were similar in the two groups. Survival of patients with echocardiographic evidence of carcinoid heart disease was reduced compared with those without cardiac involvement (p = 0.0003). ECG and chest roentgenographic findings in patients with carcinoid heart disease were nonspecific.

CONCLUSIONS

The broad spectrum of carcinoid heart disease is detailed in this large series. This includes not only right-sided valvular lesions but also left-sided involvement, pericardial effusion, and myocardial metastases.

Serial tomographic imaging with technetium-99m-sestamibi for the assessment of infarct-related arterial patency following reperfusion therapy

The purpose of this study was to determine the relationship of changes in the severity and extent of hypoperfusion on serial tomographic 99mTc-sestamibi images with patency of the infarct related artery during acute myocardial infarction. We studied 109 patients with acute myocardial infarction using tomographic 99mTc-sestamibi imaging acutely and at 18-48 hr later. Perfusion defect extent and defect area, an index of defect severity, were measured on both studies. Both defect extent and defect area were significantly (p = 0.0001) greater for anterior infarctions than for inferior and lateral infarctions. By two factor analysis of variance, the change in defect area varied significantly with both infarct location (p = 0.0001) and patency of the infarct-related artery (p = 0.002). The change in defect extent also varied significantly with both infarct location (p = 0.0001) and with patency of the infarct-related artery (p = 0.004). In patients with inferior myocardial infarction, a change in defect extent or defect area of greater than 4% or 0.017, respectively, had a positive predictive accuracy of 96% and 93%, respectively, for the identification of a patent infarct artery. Therefore, sequential changes on tomographic 99mTc-sestamibi images are of potential value for the noninvasive assessment of patency of the infarct-related artery.

Dynamic intraventricular obstruction during dobutamine stress echocardiography. A new observation

BACKGROUND

The implications of hypotension occurring during dobutamine stress echocardiography have not been elucidated. We observed in some patients that hyperdynamic left ventricular function developed during dobutamine stress echocardiography and hypothesized that intracavitary obstruction was occurring and might account for hypotension in some patients.

METHODS AND RESULTS

Fifty-seven consecutive patients undergoing dobutamine stress echocardiography underwent pulsed-wave and continuous-wave Doppler examination of the left ventricular cavity at rest and at peak dobutamine infusion. The development of an intraventricular gradient with dobutamine stress was defined as a late-peaking left ventricular Doppler velocity profile that exceeded basal velocity by at least 1 m/sec. During dobutamine stress testing, left ventricular outflow velocity or intracavitary velocity increased in all patients. Obstruction occurred in 12 patients (21%, group 1). Group 2 was the remaining 45 patients. Peak velocities in group 1 ranged from 2.0 to 5.0 m/sec (mean, 3.5 m/sec), and the mean increase from velocity at rest was 2.3 m/sec. The mean change in systolic blood pressure was significantly lower in patients in group 1 (-15 versus 4 mm Hg, p = 0.02). When the 18 patients with an ischemic response to stress testing (evidenced by new or worsening wall motion abnormalities) were excluded from analysis, systolic blood pressure response was still significantly different for the two groups (-19 versus 2 mm Hg, p = 0.03).

CONCLUSIONS

Dynamic left ventricular obstruction is a new observation; it may develop frequently in patients undergoing dobutamine stress echocardiography. Obstruction rather than ischemia may explain a decrease in blood pressure during dobutamine stress echocardiography.

Measurement of myocardium at risk by technetium-99m sestamibi: correlation with coronary angiography

Previous studies have shown that tomographic perfusion imaging with technetium-99m sestamibi (RP-30A) can accurately measure the myocardium at risk during acute myocardial infarction. The ability of coronary angiography to predict the wide variability in myocardium at risk was studied in 21 patients with their first acute myocardial infarction. In blinded fashion, two experienced angiographers provided an overall "best estimate" of the percent of left ventricular myocardium at risk considering multiple angiographic variables--infarct-related artery, location of stenosis (proximal or nonproximal), vessel diameter, length, territory and the number and size of proximal branches and collateral vessels. Many of these individual variables showed a significant association with myocardium at risk. The most important angiographic variable was the mean best estimate of the two angiographers (r = 0.89, p less than 0.0001). However, the SEE was large (8.6% of the left ventricle) and angiography significantly (p less than 0.002) overestimated myocardium at risk. When patients with an anterior or an inferior infarct were considered separately, the angiographic best estimate had a weaker correlation with myocardium at risk measured by technetium-99m sestamibi in patients in both groups (anterior infarction r = 0.65, p = 0.04; inferior infarction r = 0.65, p = 0.04. Seven patients with an inferior infarct and myocardium at risk ranging from 7% to 32% of the left ventricle had identical angiographic best estimates. Although angiographic estimates correlate closely with measurements of myocardium at risk in groups of patients, their ability to predict the myocardium at risk in individual patients is limited.

Electrocardiographic prediction of myocardial area at risk

The 12-lead electrocardiogram in 23 patients with an evolving first myocardial infarction (12 anterior and 11 inferior) was correlated with the myocardial area at risk measured by tomographic perfusion imaging with technetium-99m sestamibi. Of several electrocardiographic factors, only the extent and quantity (with and without R-wave normalization) of ST depression differed significantly between inferior and anterior evolving infarction. The myocardial area at risk was greater in anterior than in inferior evolving infarction. The extent of the myocardium at risk correlated modestly (r = 0.58) with total ST displacement in anterior evolving infarction and with total ST depression normalized to the R wave (r = 0.70) in inferior evolving infarction. Because of the large standard errors (9 to 15% of the left ventricle), estimates of the myocardial area at risk based on these electrocardiographic variables have minimal clinical value in the individual patient.

Primary angioplasty in myocardial infarction: assessment of improved myocardial perfusion with technetium-99m isonitrile

Technetium-99m-hexakis-2-methoxy-2-isobutyl-isonitrile (technetium-99m isonitrile) is a new radiopharmaceutical compound that reflects myocardial perfusion. Its kinetics, especially its lack of redistribution after intravenous administration, permits the assessment of changes in myocardial perfusion without delay of therapy. Tomographic images at rest were obtained immediately and 6 to 10 days later in 17 consecutive patients undergoing successful primary angioplasty during their first transmural myocardial infarction. Thirteen patients had anterior infarction. The initial (acute) defect size before angioplasty of 48 +/- 17% of the left ventricle decreased significantly (p less than 0.0001) to 29 +/- 19% on the late scans. There was no correlation between the time to therapy and the reduction in defect size. Twelve of the 17 patients, including 7 of the 11 patients treated after 4 h, demonstrated a definite reduction in the initial defect size. Eight patients with angiographically proved persistent coronary occlusion underwent a similar imaging sequence. The initial defect size in this group remained unchanged on the late scans (24 +/- 16% versus 26 +/- 18%, p = NS). Primary angioplasty is an effective approach toward salvaging myocardium; comparison with thrombolytic drug therapy must await the results of controlled clinical trials.

Mismatch of left ventricular function and infarct size demonstrated by technetium-99m isonitrile imaging after reperfusion therapy for acute myocardial infarction: identification of myocardial stunning and hyperkinesia

Quantitation of perfusion defect size using tomographic imaging with technetium-99m-hexakis-2-methoxy isobutyl isonitrile was performed at the time of hospital discharge in 32 patients with a first myocardial infarction who underwent successful coronary reperfusion within 8 h of the onset of chest pain. Reperfusion was accomplished with thrombolysis or primary coronary angioplasty. Radionuclide angiography was performed at discharge and 6 weeks later. There was a close correlation between perfusion defect size and values for ejection fraction and regional wall motion both at discharge (r = -0.80 and -0.75, respectively) and 6 weeks later (r = -0.81 and -0.81, respectively). There was no overall group difference in ejection fraction between the value at discharge and at 6 weeks; however, five patients had a significant increase (greater than or equal to 0.08) and six had a significant decrease (greater than or equal to 0.08) in ejection fraction. In patients with a significant increase at 6 weeks, ejection fraction was significantly lower at discharge than the value predicted from perfusion defect size (0.37 +/- 0.09 measured versus 0.47 +/- 0.13 predicted, p less than 0.05) and it improved at 6 weeks to near predicted values (0.51 +/- 0.07). In patients with a significant decrease at 6 weeks, ejection fraction was significantly higher at discharge than the value predicted from perfusion defect size (0.60 +/- 0.10 measured versus 0.50 +/- 0.10 predicted, p less than 0.05) and it decreased at 6 weeks to near predicted levels (0.51 +/- 0.09). Left ventricular ejection fraction at the time of hospital discharge is a potentially misleading index of the efficacy of reperfusion therapy for myocardial infarction. In a significant minority (34%) of patients this index does not accurately reflect perfusion defect size, apparently because of the effects of myocardial stunning and compensatory hyperkinesia.

Measurement of myocardium at risk and salvage in myocardial infarction with ST-segment depression

A patient with symptoms of acute myocardial infarction but ST-segment depression rather than elevation constitutes a clinical dilemma for which few guidelines exist. Herein we describe such a patient, in whom serial tomographic imaging with a new radiopharmaceutical agent, technetium-99m sestamibi, was useful in demonstrating a large area of myocardium at risk and subsequent substantial benefit from acute reperfusion therapy. Because this perfusion agent washes out slowly from the myocardium, imaging can be delayed for several hours; thus, acute reperfusion therapy can be performed without delay. Subsequent imaging, however, will reflect myocardial perfusion at the time of administration of the radionuclide. Additional studies with this agent may be valuable in identifying those patients with ST-segment depression who will benefit from acute reperfusion therapy.

Serial changes in myocardial perfusion using tomographic technetium-99m-hexakis-2-methoxy-2-methylpropyl-isonitrile imaging following reperfusion therapy of myocardial infarction

Resting tomographic myocardial perfusion images using technetium-99m-hexakis-2-methoxy-2-methylpropyl-isonitrile (Tc-Sestamibi) were obtained in 25 patients during their first myocardial infarction. Tc-Sestamibi was injected intravenously before acute reperfusion therapy, and repeated twice, at 18-48 hr, and at 6 to 14 days. Reperfusion was successful in 19 patients. In the patients with successful reperfusion, there was a mean decrease in the amount of hypoperfused myocardium between the initial and second studies (-9% +/- 12%, p = 0.004) and a further decrease between the second and final studies (-10% +/- 12%, p = 0.002). Nine of these 19 patients (47%) had evidence of significant improvement at the time of the second study. In six patients, significant improvement was not evident until the final study. Although tomographic imaging with Tc-Sestamibi following reperfusion therapy may show improvement in perfusion at 18-48 hr, the full extent of improvement is usually not evident until later.

Cardiogastric fistula occurring 9 years after resection of left ventricular aneurysm

An 83-year-old man, 9 years after repair of a postinfarction aneurysm of the left ventricle, developed fever, anemia, and congestive heart failure. Extensive evaluation of the gastrointestinal tract revealed no evidence of ulcer disease. While in the hospital, he developed massive hematemesis and melena and died 2 days later. At autopsy, a communication existed between a left ventricular pseudoaneurysm and the stomach to form a cardiogastric fistula. Infection of the left ventricular pseudoaneurysm may have precipitated the gastric perforation. This represents an extremely rare late complication of aneurysmectomy procedures and, to our knowledge, is the first case to be reported in the absence of primary gastrointestinal pathology.

The natural history of adults with asymptomatic, hemodynamically significant aortic stenosis

The natural history of asymptomatic, hemodynamically significant, valvular aortic stenosis in adults was documented. Of 471 patients with aortic stenosis identified by Doppler echocardiography (peak systolic flow velocity greater than or equal to 4 m/s) from January 1984 through August 1987, 143 were asymptomatic and had isolated valvular aortic stenosis. Thirty patients underwent aortic valve intervention within 3 months (group 1); the remaining 113 patients did not have an intervention within 3 months (group 2). Follow-up information was available for all patients; the mean duration of follow-up study was 20 months (range 6 to 48). Three cardiac events occurred in the 30 group 1 patients after operation (two deaths, one reoperation). Among the 113 group 2 patients, three had cardiac death presumed to be a result of the aortic stenosis; all three developed symptoms at least 3 months before death. The actuarial probability of remaining free of symptoms of angina, dyspnea or syncope for group 2 was 86% at 1 year and 62% at 2 years. For this group, the 1 and 2 year probabilities of remaining free of cardiac events, including aortic valve intervention or cardiac death, were 93% and 74%, respectively. Of all clinical and echocardiographic variables (group 2), only Doppler flow velocity (p = 0.004) and ejection fraction (p = 0.01) were independent predictors of subsequent cardiac events. Among the 44 patients (groups 1 and 2) with a flow velocity greater than or equal to 4.5 m/s, the relative risk of sustaining a cardiac event (by Cox regression analysis) was 4.9 (p = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Feasibility of tomographic 99mTc-hexakis-2-methoxy-2-methylpropyl-isonitrile imaging for the assessment of myocardial area at risk and the effect of treatment in acute myocardial infarction

99mTc-hexakis-2-methoxy-2-methylpropyl-isonitrile (Tc-Sestamibi), a new myocardial perfusion radiopharmaceutical, was injected intravenously in 11 patients within 4 hours of the onset of acute myocardial infarction before treatment with intravenous tissue-type plasminogen activator and 6-14 days later. Five patients with acute myocardial infarction who did not receive intravenous thrombolytic therapy underwent a similar injection of radiopharmaceutical. The absence of redistribution of Tc-Sestamibi permitted imaging with single-photon emission computed tomography up to 6 hours after intravenous injection to assess the distribution of myocardial perfusion at the time of administration. The region of hypoperfused myocardium on the initial images varied widely from 9% to 68% of the left ventricle and was significantly greater in anterior than in inferior infarcts (p less than 0.01). The region of hypoperfused myocardium on the final images varied widely from 0% to 63% of the left ventricle and was also greater in anterior infarcts (p less than 0.01). The final hypoperfused region correlated (r = -0.82) with the late resting ejection fraction and with the late regional wall motion score in the infarct segment for both anterior (r = -0.74) and inferior (r = -0.97) infarcts. There was a significant decrease (-13 +/- 11%, p less than 0.003) in the extent of hypoperfused myocardium between the initial and final studies in the patients who received thrombolytic therapy compared with an insignificant increase (4 +/- 6%, p greater than 0.5) in the patients who did not receive thrombolytic therapy. Tomographic imaging with Tc-Sestamibi permits determination of the amount of hypoperfused myocardium "at risk" in acute myocardial infarction. The change in myocardial perfusion determined by Tc-Sestamibi before and after therapy in acute myocardial infarction is a promising tool for assessing treatment.

Serial quantitative planar technetium-99m isonitrile imaging in acute myocardial infarction: efficacy for noninvasive assessment of thrombolytic therapy

Technetium-99m isonitrile is a new myocardial perfusion imaging agent that accumulates according to the distribution of myocardial blood flow. However, unlike thallium-201, it does not redistribute over time. This imaging agent was used with serial quantitative planar imaging to assess the initial risk area of infarction, its change over time and the relation to infarct-related artery patency in 30 patients with a first acute myocardial infarction. Twenty-three of 30 patients were treated with recombinant tissue-type plasminogen activator (rt-PA) within 4 h after the onset of chest pain. Seven patients were treated in the conventional manner without thrombolytic therapy. Technetium-99m isonitrile was injected before or at the initiation of thrombolytic therapy, and imaging was performed several hours later. These initial images demonstrated the area at risk. Repeat imaging was performed 18 to 48 h later and at 6 to 14 days after the onset of myocardial infarction to visualize the ultimate extent of infarction. The initial area at risk varied greatly (range defect integral 2 to 61) both in patients treated with rt-PA and in those who received conventional treatment. For the total group, the initial imaging defect decreased in size in 20 patients and was unchanged or larger in 10 patients. Patients with a patent infarct-related artery had a significantly greater decrease in defect size than did patients with persistent coronary occlusion (-51 +/- 38% versus -1 +/- 26%, p = 0.0001). All patients with a decrease in defect size greater than 30% had a patent infarct-related artery. In 12 patients who also had predischarge quantitative exercise thallium-201 imaging, good agreement existed between the extent and severity of myocardial perfusion defect on the last technetium-99m isonitrile study before discharge and that noted on delayed thallium-201 imaging. It is concluded that serial planar technetium-99m isonitrile myocardial imaging in patients with acute myocardial infarction undergoing thrombolytic therapy offers a new quantitative noninvasive approach for assessment of the initial risk zone as well as the success of reperfusion.

Endomyocardial biopsy in 30 patients with primary amyloidosis and suspected cardiac involvement

Thirty patients with primary amyloidosis in whom cardiac involvement was suspected underwent endomyocardial biopsies. Medical records and biopsies were reviewed and echocardiograms were interpreted by observers who were unaware of the recorded findings. Cardiac amyloidosis was documented by endomyocardial biopsy in 30 (100%) of the patients. In two patients, amyloid was present in only one of four specimens, suggesting that a minimum of four biopsy samples is necessary to eliminate the possibility of sampling error. Only 36 (55%) of 65 biopsy specimens of extracardiac tissues contained amyloid. Findings were positive for amyloidosis in 11 (58%) of 19 rectal biopsies and in 16 (52%) of 31 bone marrow biopsies. Of interest, only the endomyocardial biopsy tissues were positive for amyloid in eight (27%) of the 30 patients, among whom 12 extracardiac biopsies had been performed. Two-dimensional echocardiography was consistent with the diagnosis of amyloidosis in 19 (68%) of 28 patients and was abnormal but nonspecific in the remainder. Endomyocardial biopsy frequently provides information about cardiac involvement with amyloid when biopsy of other organs is negative or echocardiography is nonspecific.

Senile cardiac amyloidosis with myocardial dysfunction. Diagnosis by endomyocardial biopsy and immunohistochemistry

Senile cardiac amyloid discovered at autopsy is usually regarded as an incidental finding. However, in immunohistochemical studies of autopsy material, three distinct forms of senile cardiovascular amyloid have been characterized, including a systemic form that diffusely infiltrates the cardiac ventricles. The systemic form can be identified immunohistochemically with use of antiserum to human prealbumin. We diagnosed senile systemic amyloidosis causing cardiac dysfunction in five men (57 to 72 years old) by using antiserum to prealbumin in myocardial biopsy tissue. Clinically, the five patients were indistinguishable from patients with nonsecretory immunoglobulin-derived primary amyloidosis with cardiac involvement; only immunohistochemical staining of myocardial tissue distinguished between the two entities. This distinction is important, because the treatment and prognosis of the two disorders are different. We recommend immunohistochemical staining of myocardial tissue for prealbumin in patients with biopsy-proved cardiac amyloid in whom no monoclonal immunoglobulin light chain is detectable in the serum or urine.

Comparison of estrogen receptors in human premenopausal and postmenopausal uteri using isoelectric focusing

Previous studies have suggested that the estrogen receptor in the postmenopausal uterus, although capable of binding estrogen, may be inactive, that is, incapable of translocating and binding to nuclear acceptor sites. The present study uses isoelectric focusing to characterize differences in the estrogen receptor between premenopausal and postmenopausal uterine tissue. Human myometrium (15 premenopausal and ten postmenopausal samples) was examined by isoelectric focusing in the presence and absence of diisopropylfluorophosphate (DFP) and molybdate, which inhibit proteolysis and stabilize the receptor. As demonstrated previously, receptor forms could be identified in two regions of the pH gradient, one in the pH 4 to 5 region and another at pH 6 to 7. When prepared without DFP and molybdate, the percentage of receptors focusing in the pH 4 to 5 range was significantly greater for premenopausal than postmenopausal tissue (P less than .01). The addition of DFP and molybdate significantly altered the focusing pattern of postmenopausal tissue (P less than .01), increasing the percentage of binding in the pH 4 to 5 range. In the presence of DFP and molybdate, the focusing patterns of receptor from premenopausal and postmenopausal tissue were not significantly different. These data suggest that endogenous proteases are more prevalent in postmenopausal tissue and can degrade the receptor to forms that focus at a higher pH. With the inhibition of these proteases, the focusing patterns of receptors in premenopausal and postmenopausal tissue become very similar, representing the undegraded and perhaps native form of the receptor.