Aortic valve replacement for aortic stenosis with severe left ventricular dysfunction. Prognostic indicators

BACKGROUND

Aortic valve replacement for aortic stenosis (AS) carries an increased risk in the presence of left ventricular (LV) systolic dysfunction. Few data are available on the outcome of such patients.

METHODS AND RESULTS

Between 1985 and 1992, 154 consecutive patients (107 men and 47 women) with LV systolic dysfunction (ejection fraction [EF] < or = 35%) underwent aortic valve replacement for AS. The mean preoperative characteristics included EF, 27 +/- 6%; aortic valve mean gradient, 44 +/- 18 mm Hg; aortic valve area, 0.6 +/- 0.2 cm2; and cardiac output, 4.1 +/- 1.5 L/min. Simultaneous coronary artery bypass graft surgery was performed in 78 patients (51%). Perioperative (30-day) mortality was 9% (14 of 154 patients). Fifty patients died during follow-up. Coronary artery disease (P = .002) and a reduced preoperative cardiac output (P = .03) were significantly related to reduced overall survival rate by multivariate analysis. Postoperative improvement occurred in most patients; 88% were New York Heart Association class III or IV before surgery versus 7% after surgery. Postoperative EF was assessed in 76% of survivors; 76% of these demonstrated improvement. By multivariate analysis, change in EF was inversely related to coronary disease (P = .002) and preoperative aortic valve area (P = .03).

CONCLUSIONS

Despite LV dysfunction, the risk of aortic valve replacement for AS was acceptable and related to coronary artery disease and mean aortic gradient, and long-term survival was related to coronary disease and cardiac output. Improvement in symptoms and EF occurred in most patients.

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.

Effect of Doppler echocardiography on utilization of hemodynamic cardiac catheterization in the preoperative evaluation of aortic stenosis

OBJECTIVE

To examine the use of Doppler echocardiography in preoperative assessment of aortic stenosis and to determine its effect on subsequent use of hemodynamic cardiac catheterization.

MATERIAL AND METHODS

We retrospectively reviewed a consecutive series of 574 adult patients who underwent aortic valve replacement for aortic stenosis between 1990 and 1992 at our institution. The use of Doppler echocardiography and cardiac catheterization and the predictive factors for use of hemodynamic catheterization were analyzed.

RESULTS

After Doppler echocardiography in 423 patients, invasive hemodynamic assessment of the severity of aortic stenosis was performed in only 42% (179 patients). The use of cardiac catheterization declined over time (54% in 1990, 40% in 1991, and 35% in 1992) (P = 0.003), whereas no significant change in the baseline clinical characteristics of the population or in severity of stenosis as determined by Doppler echocardiography occurred during that time. Multivariate analysis identified the following variables as independent predictors of use of cardiac catheterization after Doppler echocardiography: clinically not severe aortic stenosis, mean gradient of less than 50 mm Hg determined by Doppler echocardiography, Doppler-determined aortic valve area of more than 0.8 cm2 or not calculated, attending cardiologist not specialized in echocardiography, and earlier year of assessment.

CONCLUSION

After Doppler echocardiography, less than 50% of our patients undergoing aortic valve replacement for aortic stenosis have cardiac catheterization preoperatively. The use of cardiac catheterization after Doppler echocardiography--thus, duplication of hemodynamic assessment--declined significantly over time during the study period. Decline in the use of catheterization is related to the degree of diagnostic certainty provided by Doppler echocardiography and to the level of familiarity of the attending cardiologist with the technique.

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.

Cardiac echinococcosis: case report of unusual echocardiographic appearance

An unusual echocardiographic appearance of a cardiac echinococcal lesion confirmed intraoperatively is described in a patient with nonspecific cardiac complaints. Although previous reports have emphasized the echolucent, often multiseptated nature of echinococcal lesions, such characteristics were absent in this case. Thus, in the appropriate clinical setting, echinococcal infection should be included in the differential diagnosis of solid mass lesions of the heart because the surgical approach may need to be altered.

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.

Progression of aortic stenosis in adults: new insights provided by Doppler echocardiography

Aortic stenosis is a progressive disease. The mechanisms and patterns of progression have been studied over the years using clinical assessment, cardiac catheterization, and more recently, Doppler echocardiography. Doppler is the ideal tool with which to study the progression of aortic stenosis since it provides accurate hemodynamic data non-invasively and, hence, can be repeated serially over long follow up periods. Recent Doppler echocardiographic studies have shown that the progression of aortic stenosis occurs with a wide range of individual variations, and that its rate and pattern cannot be predicted at the time of initial evaluation. However, it does follow a linear pattern, and individual trends can therefore be determined in a given patient. Symptoms lack specificity and, at a given point in time, do not predict progression. However, new and/or worsening symptoms are a mark of significant hemodynamic progression. The relationship between the cause of aortic stenosis and its progression remains imperfectly documented, and further longitudinal studies should focus on this question.

Progression of aortic stenosis in adults: new appraisal using Doppler echocardiography

This study examined progression of aortic stenosis (AS) as assessed by Doppler echocardiography. One hundred twelve consecutive adult patients had calcific AS and underwent three examinations during a mean 25-month period (range 7 to 54 months). At the time of entry into the study, mean values for initial peak aortic velocity and ejection fraction (EF) were 2.9 +/- 0.7 m/sec and 63 +/- 10%, respectively; 52% of the patients were symptomatic. At the third examination the percentage of symptomatic patients increased to 65% (p = 0.0039 compared to baseline values), and the aortic peak velocity increased to 3.3 +/- 0.8 m/sec (p less than 0.001). Age, sex, and EF were not predictors of progression. Documented coronary artery disease (in 57 patients) did not affect progression, and neither did the aortic peak velocity at the time of entry into the study. Thirty-eight patients reported an increase in symptoms from the first to third examination, and their rate of progression was significantly different from that of the rest of the population: 0.33 +/- 0.50 m/sec/yr compared to 0.18 +/- 0.26 m/sec/yr (p less than 0.03).

Influence of coronary artery disease on morbidity and mortality after abdominal aortic aneurysmectomy: a population-based study, 1971-1987

The prognostic importance of coronary artery disease at the time of elective abdominal aortic aneurysmectomy was evaluated among 131 residents of Olmsted County, Minnesota who underwent elective aneurysmectomy from 1971 to 1987 and were followed up to 1988 for death and cardiac events (cardiac death, myocardial infarction, coronary bypass surgery and angioplasty). Before aneurysmectomy, 75 patients (Group 1) had no clinically recognized coronary disease, 47 patients (Group 2) had suspected or overt uncorrected coronary artery disease (history of prior myocardial infarction, angina or a positive stress test) and 9 patients (Group 3) had undergone coronary artery bypass grafting or coronary angioplasty. The 30 day operative mortality rate was 3% (2 of 75) in Group 1 and 9% (4 of 47) in Group 2 (p = 0.15). According to Kaplan-Meier analysis, estimated survival 8 years after aneurysmectomy was 59% (expected rate 68%, p = 0.29) in Group 1 versus 34% (expected rate 61%, p = 0.01) in Group 2. The cumulative incidence rate of cardiac events at 8 years was 15% and 61%, respectively, for patients without and with suspected/overt coronary artery disease (p less than 0.01). Using multivariable proportional hazards analysis, uncorrected coronary artery disease was associated with a nearly twofold increased risk of death (hazard ratio 1.79, 95% confidence interval 1.06 to 3.00) and a fourfold increased risk of cardiac events (hazard ratio 3.71, 95% confidence interval 1.79 to 7.69). These population-based data support an aggressive life-long approach to the management of coronary artery disease in patients undergoing abdominal aortic aneurysmectomy.