Comparison of intravenous myocardial contrast echocardiography and low-dose dobutamine echocardiography for predicting left ventricular functional recovery following acute myocardial infarction

Akinesia after acute myocardial infarction (AMI) may be reversible or irreversible. Distinguishing these 2 entities early after AMI is difficult, but clinically important. Previous studies have shown that myocardial contrast echocardiography (MCE) and low-dose dobutamine echocardiography (DE) may both be useful in this setting. However, there are few data regarding the relative and combined value of these techniques. The aim of this study was to compare the utility of real-time intravenous MCE and low-dose DE in the early prediction of functional recovery of akinetic myocardium after AMI. Thirty-seven patients were studied 3 +/- 2 days after an AMI. Each subject underwent real-time MCE using an intravenous infusion of perflutren microbubbles. Immediately after this, low-dose DE was performed. Contrast opacification and wall motion were determined by experienced observers blinded to clinical data. Repeat echocardiograms were obtained 51 +/- 19 days later and wall motion at rest was scored by an observer blinded to clinical data. Normal contrast opacification predicted functional recovery with a positive predictive value of 63%, a negative predictive value of 73%, and an accuracy of 66%. Residual contractility during low-dose DE had a positive predictive value of 82%, a negative predictive value of 72%, and a predictive accuracy of 76%. When the 2 tests were concordant (64%), they had a positive predictive value of 81%, a negative predictive value of 85%, and a predictive accuracy of 83%. Low-dose DE was superior to intravenous MCE in the prediction of functional recovery of akinetic myocardium after AMI, but the combination of both maximizes predictive accuracy.

Appropriate use of exercise testing prior to administration of drugs for treatment of erectile dysfunction

Selective inhibitors of phosphodiesterase type 5 prevent the breakdown of cyclic guanosine monophosphate resulting in enhanced penile erection and are used for the treatment of erectile dysfunction. Those agents, by way of vasodilator effects could interact with the systemic vasculature and could potentially affect the cardiac patient. During sexual intercourse, heart rate and blood pressure increase as with other forms of exertion. Stress to the heart during sexual intercourse is similar than that observed during other common daily activities. This article reviews the literature and provides recommendations regarding the evaluation of patients with known or suspected cardiac disease in whom therapy for erectile dysfunction is being considered. Patients who seek therapy for erectile dysfunction should undergo to individualized medical evaluation before a prescription is issued. Patients requiring therapy with long-acting nitrates should not receive prescriptions for phosphodiesterase inhibitors. Patients who are likely to develop angina with sexual exertion should not take phosphodiesterase inhibitors, as they may be tempted to take sublingual nitroglycerin. Stress testing is indicated if exercise capacity is uncertain or if significant myocardial ischemia is suspected.

Left atrial volume: a powerful predictor of survival after acute myocardial infarction

BACKGROUND

After acute myocardial infarction (AMI), diastolic function assessed by Doppler echocardiography provides important prognostic information that is incremental to systolic function. However, Doppler variables are affected by multiple factors and may change rapidly. In contrast, left atrial (LA) volume is less influenced by acute changes and reflects subacute or chronic diastolic function. This may be of importance when one assesses risk in patients with AMI.

METHODS AND RESULTS

Three hundred fourteen patients with AMI who had a transthoracic echocardiogram with assessment of left ventricular (LV) systolic and diastolic function and measurement of LA volume during admission were identified. The LA volume was corrected for body surface area, and the population was divided according to LA volume index of 32 mL/m2 (2 SDs above normal). LA volume index was >32 mL/m2 in 142 (45%). The primary study end point was all-cause mortality. During follow-up of 15 (range 0 to 33) months, 46 patients (15%) died. LA volume index was a powerful predictor of mortality and remained an independent predictor (hazard ratio 1.05 per 1-mL/m2 change, 95% CI 1.03 to 1.06, P<0.001) after adjustment for clinical factors, LV systolic function, and Doppler-derived parameters of diastolic function.

CONCLUSIONS

Increased LA volume index is a powerful predictor of mortality after AMI and provides prognostic information incremental to clinical data and conventional measures of LV systolic and diastolic function.

Factors associated with progression of carcinoid heart disease

BACKGROUND

By releasing vasoactive substances into the circulation, carcinoid tumors can cause right-sided valvular heart disease. Factors associated with the progression of carcinoid heart disease are poorly understood. We conducted a retrospective study to identify such factors.

METHODS

Our sample included 71 patients with the carcinoid syndrome who underwent serial echocardiographic studies performed more than one year apart and 32 patients referred directly for surgical intervention after an initial echocardiographic evaluation. A score for carcinoid heart disease was determined on the basis of an assessment of valvular anatomy and function and the function of the right ventricle. An increase of more than 25 percent in the score between studies was considered suggestive of disease progression. Tumor progression was assessed on the basis of abdominal computed tomographic scans and changes in the level of urinary 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of serotonin.

RESULTS

Of the patients with serial echocardiographic studies, 25 (35 percent) had an increase of more than 25 percent in the cardiac score. As compared with patients whose score changed by 25 percent or less, these patients had higher urinary peak 5-HIAA levels (median, 265 mg per 24 hours [interquartile range, 209 to 593] vs. 189 mg per 24 hours [interquartile range, 75 to 286]; P=0.004) and were more likely to have biochemical progression (10 of 25 patients vs. 9 of 46, P=0.05) and to have received chemotherapy (13 of 25 vs. 10 of 46, P=0.009). Logistic-regression analysis showed that a higher peak urinary 5-HIAA level and previous chemotherapy were predictors of an increase in the cardiac score that exceeded 25 percent (odds ratio for each increase in 5-HIAA of 25 mg per 24 hours, 1.08 [95 percent confidence interval, 1.03 to 1.13]; P=0.009); odds ratio associated with chemotherapy, 3.65 [95 percent confidence interval, 1.74 to 7.48]; P=0.001).

CONCLUSIONS

Serotonin is related to the progression of carcinoid heart disease, and the risk of progressive heart disease is higher in patients who receive chemotherapy than in those who do not.

Mycotic aneurysm of the left ventricle: echocardiographic diagnosis

We report an unusual case of myocardial mycotic aneurysm of the left ventricle resulting from a healed myocardial abscess caused by an aortic regurgitant jet lesion. The diagnosis was made during intraoperative transesophageal echocardiography and confirmed by surgical inspection. The echocardiographic features are described.

Prediction of mortality in patients with left ventricular hypertrophy by clinical, exercise stress, and echocardiographic data

OBJECTIVES

This study evaluated the clinical, exercise stress test, and echocardiographic predictors of mortality and cardiac events in patients with left ventricular hypertrophy (LVH).

BACKGROUND

Left ventricular hypertrophy is associated with an increased risk of cardiovascular morbidity and mortality.

METHODS

Symptom-limited treadmill exercise echocardiography was performed for evaluation of coronary artery disease in 483 patients (age, 66 +/- 11 years; 281 men) with LVH. End points during follow-up were all-cause mortality and hard cardiac events (cardiac death and nonfatal myocardial infarction [MI]).

RESULTS

Forty-six patients died and 14 had nonfatal MI. The cumulative mortality rate was higher in patients with abnormal exercise echocardiography (3% vs. 0.4% at one year, 11.7% vs. 3.7% at three years, and 18.3% vs. 9.5% at five years, p < 0.001). In a sequential multivariate analysis model of clinical, exercise test, and rest and exercise echocardiographic data, incremental predictors of mortality were workload (hazard ratio [HR], 0.5; 95% confidence interval [CI], 0.3 to 0.9), rate pressure product (HR, 0.7; 95% CI, 0.5 to 0.9), left ventricular (LV) mass index (HR, 1.4; 95% CI, 1.1 to 1.8), and failure to increase ejection fraction (EF) with exercise (HR, 2.1; 95% CI, 1.1 to 3.8). Predictors of cardiac events were history of coronary artery bypass grafting (HR, 2.6; 95% CI, 1.2 to 5.4), lower exercise rate-pressure product (HR, 0.6; 95% CI, 0.5 to 0.8), resting wall motion score index (HR, 1.4; 95% CI, 1.1 to 1.8), and failure to increase EF with exercise (HR, 3.3; 95% CI, 1.6 to 6.9).

CONCLUSIONS

In patients with LVH, LV mass index and EF response to exercise are independent predictors of mortality, incremental to clinical and exercise test data and resting LV function. A normal exercise echocardiogram predicts a relatively low mortality rate during the following three years.

Association of cholesterol levels, hydroxymethylglutaryl coenzyme-A reductase inhibitor treatment, and progression of aortic stenosis in the community

OBJECTIVES

This study was designed to analyze the association among cholesterol levels, lipid-lowering treatment, and progression of aortic stenosis (AS) in the community.

BACKGROUND

Aortic stenosis is a progressive disease for which there is no known medical treatment to prevent or slow progression. Despite plausible pathologic mechanisms linking hypercholesterolemia to AS progression, clinical studies have been inconsistent and affected by referral bias, and the role of lipid-lowering therapy is uncertain.

METHODS

We determined the association between blood cholesterol levels and progression of native AS (assessed by Doppler echocardiography at baseline and at least six months later; mean interval, 3.7 +/- 2.3 years) in a community-based study of 156 patients (age 77 +/- 12 years; 90 men). Thirty-eight patients received statin treatment during follow-up.

RESULTS

In untreated subjects, mean gradient increased from 22 +/- 12 mm Hg to 39 +/- 19 mm Hg, and aortic valve area (AVA) decreased from 1.20 +/- 0.35 cm(2) to 0.91 +/- 0.33 cm(2) (both p < 0.001). The annualized change in AVA was -0.09 +/- 0.17 cm(2)/year (-7% +/- 13%/year). Neither total cholesterol (r = -0.01, p = 0.92) nor low-density lipoprotein cholesterol (r = 0.01; p = 0.88) showed a significant correlation to AS progression. Nevertheless, progression of AS was slower in patients receiving statins compared with untreated patients (decrease in AVA -3 +/- 10% vs. -7 +/- 13% per year, respectively; p = 0.04), even when adjusted for age, gender, cholesterol, and baseline valve area (p = 0.04). The association of statin treatment with slower progression was confirmed when analysis was restricted to patients coming for a systematic follow-up (p=0.02). The odds ratio of AS progression with statin treatment was 0.46 (95% confidence interval, 0.21 to 0.96).

CONCLUSIONS

In the community, progression of AS shows no trend of association with cholesterol levels. Statin treatment, however, is associated with slower progression, suggesting that the effects of statin treatment on progression of AS should be pursued with appropriate clinical trials.

Prognostic significance of the location of wall motion abnormalities during exercise echocardiography

OBJECTIVES

Our aim was to determine whether location of wall motion abnormalities (WMAs) during exercise echocardiography provides independent prognostic value.

BACKGROUND

The effect of the location of WMAs during stress echocardiography on prognostic outcome is unknown.

METHODS

We studied 4,347 patients (mean age, 61 +/- 12 years; 2,230 men) with known or suspected coronary artery disease by symptom-limited exercise echocardiography. An abnormal result was defined as resting or exercise-induced WMA. End points were cardiac death and nonfatal myocardial infarction (MI).

RESULTS

There were 133 cardiac events (54 cardiac deaths and 79 nonfatal MIs) during follow-up (median, three years). In a multiple-stepwise multivariate analysis model, clinical and exercise electrocardiography predictors of cardiac events were age, gender, hypertension, typical chest pain, previous MI, smoking, and resting ejection fraction. The percentage of ischemic segments at peak exercise provided additional information to the model (p = 0.0001). The presence of abnormalities in the left anterior descending (LAD) coronary artery distribution had an additional independent effect for the prediction of cardiac events (p = 0.001). Among patients with exercise echocardiographic abnormalities in a single vascular region, those with abnormalities in the left anterior descending coronary artery distribution had a higher event rate than patients with abnormalities elsewhere (3.2% vs. 2.1% at three years and 10.8% vs. 2.1% at five years; p = 0.009). CONCLUSIONS; Exercise WMAs in the distribution of the LAD coronary artery are associated with an increased risk of cardiac death and nonfatal MI. This risk is independent of the resting ejection fraction and the extent of WMAs during exercise.

Safety of dobutamine stress echocardiography in patients with unruptured intracranial aneurysms

Dobutamine stress echocardiography has been increasingly used for the preoperative assessment of patients who undergo major vascular surgery. The safety of this modality has been well documented in various patient subgroups, including patients with aneurysms of the aorta. No previous reports, however, have addressed the safety of this form of stress testing in patients with unruptured intracranial aneurysms. After reviewing the experience of 2 institutions, we identified 40 patients who underwent dobutamine stress echocardiography while harboring at least 1 unruptured intracranial aneurysm, and found no evidence of aneurysm instability in relation to the dobutamine infusion. Although vasodilator stress modalities should intuitively be the non-exercise stress technique of choice in these patients, stress echocardiography with the use of dobutamine appears to be safe and represents an acceptable option when used for diagnostic purposes or preoperative risk stratification in this patient population.

Metastatic carcinoid tumor to the heart: echocardiographic-pathologic study of 11 patients

OBJECTIVE

We sought to investigate the clinical and echocardiographic (echo) characteristics of metastatic carcinoid tumor in the heart.

BACKGROUND

Right-sided valvular dysfunction is the hallmark of carcinoid heart disease. Cardiac metastases are uncommon in carcinoid syndrome. Features of patients with metastatic carcinoid tumor involving the heart (MCH) have not been well described.

METHODS

From 1985 through 1999, 11 patients (8 male, 3 female), mean age +/- standard deviation, 58 +/- 6 years, were seen who had pathologically confirmed MCH. All patients had echoes, which were reviewed retrospectively.

RESULTS

All patients with MCH had carcinoid syndrome. The primary carcinoid tumor was in the small bowel in 83% of patients, and all patients had hepatic metastases. On pathologic review, the 11 patients had 15 MCH tumors. All metastases were intramyocardial. The MCH involved the right ventricle in 40%, left ventricle in 53%, and ventricular septum in 7%. The average size of macroscopic tumors was 1.8 +/- 1.2 cm. Nine MCH tumors were detected by echo in 6 of the 11 patients (55%). Mean echo-detected tumor size was 2.4 cm (range, 1.2 to 4). All tumors noted by echo were well circumscribed, non-infiltrating, and homogeneous. In the 5 other patients, review of autopsy records revealed 6 macroscopic tumors, mean size 0.35 cm (range, 0.2 to 0.4), none detected by echo even retrospectively. Carcinoid valve disease was present in 8 of the 11 MCH patients. The tricuspid valve was affected in all 8 patients (73%), pulmonary valve in 7 (64%), and left sided valves in 4 (36%) All patients with MCH identified by echo had cardiac surgery, 3 primarily for carcinoid valve disease and 2 for non-carcinoid cardiac disease; in 1 patient, MCH was the primary indication for cardiac surgery.

CONCLUSIONS

MCH is uncommon but can be easily identified by echo if tumor size is >/=1.0 cm. In patients without valvular dysfunction, MCH may be the only manifestation of carcinoid heart disease. A search for MCH should be an integral part of the echo exam in patients with carcinoid syndrome.

Respiratory failure in tetanus: case report and review of a 25-year experience

The objectives of the study were to describe a novel presentation of tetanus and to review the course of the respiratory component and the treatment and management of the disease. A case report is presented with a review of a 25-year experience at Mayo Clinic. We describe the case of a 65-year-old woman who presented with persistent hiccups, dyspnea, and pleurisy of 3 days duration that was caused by tetanus from inadequate secondary immunity. She required intubation for progressive trismus and laryngospasm-associated respiratory failure. Infusion of lorazepam did not control her spasms. Refractory spasms and hiccups resolved with fentanyl and cisatracurium therapy. After 3 weeks, the patient was weaned from the ventilator with complete recovery. In the past 25 years, nine additional patients have presented to Mayo Clinic with acute tetanus. Respiratory failure requiring intubation developed in seven patients, and six of the seven intubated patients survived with minimal deficits. The prognosis of tetanus is favorable if it is diagnosed promptly and if treatment and supportive measures are begun. To our knowledge, this is the first report of a patient with acute tetanus presenting with hiccups. This report also confirms the results of previous studies that suggested a need for improved immunity in the elderly population.

Carcinoid heart disease: impact of pulmonary valve replacement in right ventricular function and remodeling

BACKGROUND

Carcinoid heart disease characteristically affects tricuspid (TV) and pulmonary valves (PV), and TV replacement is helpful in selected patients. There is uncertainty, however, regarding optimal surgical management of PV regurgitation.

METHODS AND RESULTS

We reviewed 22 patients having operation for carcinoid heart disease and compared those having TV and PV replacement (n=12), to those who underwent TV replacement and excision of the PV (n=10). Pre- and postoperative right ventricular (RV) size and dysfunction were assessed by consensus of 2 echocardiographers blinded to type of surgical treatment. RV dysfunction was graded as none (0), mild (1), moderate (2), or severe (3). RV size was graded as normal (0), or mild (1), moderate (2), or severe (3) enlargement. Preoperatively, RV size (2.2+/-0.8 [no PVR]versus 2.7+/-0.6 [with PVR], P=0.15), RV dysfunction (0.9+/-0.9 [no PVR]versus 1.4+/-0.7 [with PVR], P=0.14), and NYHA class were similar in the 2 groups. Postop RV size decreased inpatients with PVR, 2.7+/-0.6 to 1.7+/-1.0 (P=0.008), but did not change appreciably in those without PVR, 2.2+/-0.8 to 2.3+/-0.8 (P=0.67). There was no significant change in RV dysfunction after surgery, 1.4+/-0.7 to 1.8+/-0.9 with PVR (P=0.26) and 0.9+/-0.9 to 1.6+/-0.9 without PVR (P=0.07).

CONCLUSIONS

PV replacement appears to have a beneficial effect on RV size in patients after surgery for carcinoid heart disease. This may have important implications for RV remodeling after PV replacement.

Severe pulmonary hypertension in patients with severe aortic valve stenosis: clinical profile and prognostic implications

OBJECTIVES

We analyzed the clinical characteristics and outcomes of 47 patients with severe pulmonary hypertension (PHT) and severe aortic valve stenosis (AS) from 1987 to 1999.

BACKGROUND

The prognostic implications of severe pulmonary hypertension in patients with severe AS are poorly understood.

METHODS

The mean age of patients was 78 years (range 47 to 91 years), and 37 patients (79%) were in New York Heart Association (NYHA) functional class III or IV. Aortic valve replacement (AVR) was performed in 37 patients (79%) and 10 patients (21%) were treated conservatively.

RESULTS

In the group that had AVR, there were six perioperative deaths (16%) and nine late deaths, resulting in a total mortality of 32%. In the conservatively treated group, there were eight deaths (80%) on follow-up. Severe PHT was an independent predictor of perioperative mortality. However, perioperative mortality was independent of the severity of left ventricular systolic dysfunction or concomitant coronary artery bypass grafting. Aortic valve replacement was associated with significant improvement in left ventricular ejection fraction, the severity of PHT and NYHA functional class. The difference between long-term survival of the operative survivors and the expected survival from life tables was not statistically significant.

CONCLUSIONS

The prognosis for patients with AS and severe PHT treated conservatively without AVR is dismal. Although AVR is associated with higher than usual mortality, the potential benefits outweigh the risk of surgery.

Functional and prognostic significance of exercise-induced ventricular arrhythmias in patients with suspected coronary artery disease

Our aims were to assess (1) the relation between exercise-induced ventricular arrhythmia (VA) and myocardial wall motion abnormalities during exercise echocardiography in patients with suspected coronary artery disease (CAD), and (2) the effect of this relation on outcome. We studied the clinical and prognostic significance of exercise-induced VA in 1,460 patients (mean age 64 +/- 10 years; 867 men) with intermediate pretest probability of CAD and no history of previous myocardial infarction or revascularization who underwent exercise echocardiography. Exercise-induced VA occurred in 146 patients (10%). Compared with patients without VA, those with VA had a greater prevalence of abnormal exercise echocardiographic findings (48% vs 29%, p = 0.001) and ischemia on exercise echocardiography (39% vs 22%, p = 0.001), greater increase in wall motion score index with exercise (0.14 +/- 0.28 vs 0.06 +/- 0.18, p <0.0001), and a greater percentage of abnormal segments with exercise (21 +/- 30% vs 9 +/- 19%, p <0.0001). During follow-up (median 2.7 years), cardiac death and nonfatal myocardial infarction occurred in 36 patients. In multivariate analysis of combined clinical and exercise stress test variables, independent predictors of cardiac events were exercise-induced VA (chi-square 4.7, p = 0.03) and exercise heart rate (chi-square 18, p = 0.0001). The percentage of abnormal myocardial segments with exercise echocardiography was the most powerful predictor of VA (chi-square 31, p = 0.0001) and cardiac events (chi-square 15, p = 0.0001). In patients with suspected CAD, exercise-induced VA is associated with a greater risk of cardiac death and nonfatal myocardial infarction. This risk is attributed to the relation between VA and the extent and severity of left ventricular functional abnormalities with exercise.

Sex differences in evaluation and outcome after stress testing

OBJECTIVE

To examine sex differences in evaluation and outcome after stress testing for coronary artery disease (CAD) in a geographically defined cohort.

SUBJECTS AND METHODS

Subjects were residents of Olmsted County, Minnesota, who underwent an initial stress test between January 1, 1987, and December 31, 1990. End points included referral for coronary angiography, death, and cardiac events, defined as cardiac death, nonfatal myocardial infarction, or congestive heart failure.

RESULTS

A total of 2276 men and 1270 women under went stress tests. Women were older and had more risk factors and comorbidities (P < .05). Among persons without documented CAD (86% of the cohort), the median probability of CAD was 11% (interquartile range, 5%-25%) for men and 8% (interquartile range, 2%-31%) for women (P < .001). Within 6 months after stress testing, 9% of men and 7% of women underwent coronary angiography. Among persons without documented CAD, there was no sex difference in referral for angiography when the stress test result was negative. When the test result was positive, men were more likely to be referred for angiography (adjusted odds ratio [OR] for male sex, 2.02; 95% confidence interval [CI], 1.21-3.38; P = .008). After adjusting for the predicted probability of CAD, this association was no longer detected (adjusted OR for male sex, 0.67; 95% CI, 0.26-1.73; P = .41). Among persons with documented CAD, no sex difference was noted. After a mean +/- SD follow-up of 7.6 +/- 2.7 years and among persons without documented CAD, male sex was associated with a higher adjusted risk of death (relative risk for male sex, 1.40; 95% CI, 1.05-1.86; P = .02) and cardiac events (relative risk for male sex, 1.67; 95% CI, 1.24-2.26; P < .001). Among persons with documented CAD, no sex difference in outcome was noted.

CONCLUSION

These population-based data indicate that, when the diagnosis of CAD was not established, there was a greater use of angiography among men with positive stress test results, which could be attributed to the increased probability of CAD in men. In the absence of documented CAD, men fared worse than women, with an increase in the risk of death and cardiac events. Among persons with documented CAD, no sex difference in use of angiography and outcome was noted.

Time to onset of regional relaxation: feasibility, variability and utility of a novel index of regional myocardial function by strain rate imaging

OBJECTIVES

Time to onset of regional relaxation (T(R)) has been proposed as a novel index of regional myocardial function. This study sought to prospectively establish the feasibility and variability of T(R) in healthy volunteers (CONTROL) and to examine its utility in patients with inducible ischemia (PATIENT).

BACKGROUND

Strain rate imaging (SRI) depicts myocardial deformation and enables quantitation of regional myocardial function with high temporal and spatial resolution. Thus, regional mechanical events can be accurately timed with SRI. The time point of regional transition from contraction to relaxation is altered in pathologic states.

METHODS

Resting mean segmental T(R) was determined in 60 subjects: 20 in the CONTROL group and 40 in the PATIENT group. T(R) was also measured at peak dobutamine stress in the PATIENT group. An automated image analysis program determined the time point of transition from regional contraction to relaxation activity, and calculated T(R), defined as the time, in milliseconds, from the electrocardiogram R-wave to this transition point.

RESULTS

Automated T(R) measurements were feasible in more than 90% of the segments in CONTROL and PATIENT groups. Mean T(R) was 353 +/- 24 ms and was shorter in the mid segments compared to apical and basal segments. Intra- and interobserver variability were low (6% and 9%, respectively). In the PATIENT group, the percent decrease in T(R) during dobutamine stress was significantly higher in normal compared to ischemic segments (30% vs. 19%, respectively, p = 0.01). A percent change >20% in T(R) identified patients with an ischemic response during dobutamine infusion (sensitivity 92%, specificity 75%).

CONCLUSIONS

T(R), a novel quantitative index of regional myocardial function, can be determined with low variability and satisfactory feasibility in routine clinical settings. Percent change in T(R) identifies ischemic segments during dobutamine stress echocardiography (DSE) and may allow quantitative assessment of DSE.

Outcome after abnormal exercise echocardiography for patients with good exercise capacity: prognostic importance of the extent and severity of exercise-related left ventricular dysfunction

OBJECTIVES

We sought to define the prognostic implications of the extent and severity of exercise echocardiographic abnormalities in patients with good exercise capacity. BACKGROUND; The exercise capacity of patients with known or suspected coronary artery disease (CAD) is of prognostic importance, as is the extent of exercise-related left ventricular (LV) hypoperfusion or dysfunction.

METHODS

We examined the outcomes of 1,874 patients with known or suspected CAD (mean age 64 +/- 10 years, 64% men) who had good exercise capacity (> or = 5 metabolic equivalents [METs] for women, > or = 7 METs for men) but abnormal exercise echocardiograms and analyzed the potential association between clinical, exercise and echocardiographic variables and subsequent cardiac events.

RESULTS

Multivariate predictors of time to cardiac death or nonfatal myocardial infarction (MI) were diabetes mellitus (risk ratio [RR] 1.88; 95% confidence interval [CI] 1.2 to 3.0), history of MI (RR 2.44; 95% CI 1.6 to 3.6) and an increase or no change in LV end-systolic size in response to exercise (RR 1.61; 95% CI 1.1 to 2.5). Using echocardiographic variables that were of incremental prognostic value, we were able to stratify the cardiac risk of the study population; cardiac death or nonfatal MI rate per person-year of follow-up was 1.6% for patients who had a decrease in LV end-systolic size in response to exercise (n = 1,330) and 1.2% for patients who did not have any severely abnormal LV segments immediately after exercise (n = 868).

CONCLUSIONS

In patients with good exercise capacity, echocardiographic descriptors of the extent and severity of exercise-related LV dysfunction were of independent and incremental prognostic value. Stratification of patients into low- and higher risk subgroups was possible using these exercise echocardiographic characteristics.

Prognostic value of exercise echocardiography in 5,798 patients: is there a gender difference?

OBJECTIVES

This study was designed to determine the effect of gender on the prognostic value of exercise echocardiography.

BACKGROUND

Limited information exists regarding gender differences in prognostic value of exercise echocardiography.

METHODS

We obtained follow-up (3.2 +/- 1.7 years) in 5,798 consecutive patients who underwent exercise echocardiography for evaluation of known or suspected coronary artery disease.

RESULTS

There were 3,322 men (mean age 62 +/- 12 years) and 2,476 women (mean age 62 +/- 12 years) (p = 0.7). New or worsening wall motion abnormalities developed with exercise in 35% of men and 25% of women (p = 0.001). Cardiac events, including cardiac death (107 patients) and nonfatal myocardial infarction (148 patients), occurred in 5.3% of men and 3.1% of women (p = 0.001). Addition of the percentage of ischemic segments to the clinical and rest echocardiographic model provided incremental information in predicting cardiac events for both men (chi(2) = 137 to 143, p = 0.014) and women (chi(2) = 72 to 76, p = 0.046). By multivariate analysis, exercise electrocardiographic and exercise echocardiographic predictors of cardiac events in both men and women were workload and exercise wall motion score index. There was no significant interaction effect of rest echocardiography (p = 0.79), exercise electrocardiography (p = 0.38) or exercise echocardiography (p = 0.67) with gender.

CONCLUSIONS

Although cardiac events occurred more frequently in men, the incremental value of exercise echocardiography was comparable in both genders. Of all exercise electrocardiographic and exercise echocardiographic variables, workload and exercise wall motion score index had the strongest association with outcome. The results of exercise echocardiography have comparable implications in both men and women.

Cardiovascular effects of sildenafil during exercise in men with known or probable coronary artery disease: a randomized crossover trial

CONTEXT

The relationship between sildenafil citrate use and reported adverse cardiovascular events in men with coronary artery disease (CAD) is unclear.

OBJECTIVE

To evaluate the cardiovascular effects of sildenafil during exercise in men with CAD.

DESIGN, SETTING, AND SUBJECTS

Randomized, double-blind, placebo-controlled crossover trial conducted March to October 2000 at a US ambulatory-care referral center among 105 men with a mean (SD) age of 66 (9) years who had erectile dysfunction and known or highly suspected CAD.

INTERVENTIONS

All patients underwent 2 symptom-limited supine bicycle echocardiograms separated by an interval of 1 to 3 days after receiving a single dose of sildenafil (50 or 100 mg) or placebo 1 hour before each exercise test.

MAIN OUTCOME MEASURES

Hemodynamic effects of sildenafil during exercise (onset, extent, and severity of ischemia) assessed by exercise echocardiography.

RESULTS

Mean (SD) resting ejection fraction was 56% (7%) (range, 39%-68%). After sildenafil use, resting systolic blood pressure was reduced from 135 (19) mm Hg to 128 (17) mm Hg, for a mean change of -7 mm Hg (95% confidence interval [CI], -9 to -4 mm Hg; P<.001). After placebo use, the mean (SD) change was from 135 (20) mm Hg to 133 (19) mm Hg, a difference of -2 mm Hg (95% CI, -6 to 0.3 mm Hg; P =.08). The difference between mean change after sildenafil and placebo use was 4.3 (95% CI, 0.9-7.7; P =.01). Resting heart rate, diastolic blood pressure, and wall motion score index (a measure of the extent and severity of wall motion abnormalities) did not change significantly in either group. Exercise capacity was similar with sildenafil use (mean [SD], 4.5 [1.0] metabolic equivalents) and placebo use (mean [SD], 4.6 [1.0] metabolic equivalents; mean difference, 0.07; 95% CI, -.06 to 0.19; P =.29). Exercise blood pressure and heart rate increments were similar. Dyspnea or angina developed in 69 patients who took sildenafil and 70 patients who took placebo (P =.89); exercise electrocardiography was positive in 12 patients (11%) who took sildenafil and 17 patients (16%) who took placebo (P =.09). Exercise-induced wall motion abnormalities developed in similar numbers of patients after sildenafil and placebo use (84 and 86 patients, respectively; P =.53). Wall motion score index at peak exercise was similar after sildenafil and placebo use (mean [SD], 1.4 [0.4] vs 1.4 [0.4]; mean difference, 0.01; 95% CI, -0.01 to 0.03; P =.40).

CONCLUSION

In men with stable CAD, sildenafil had no effect on symptoms, exercise duration, or presence or extent of exercise-induced ischemia, as assessed by exercise echocardiography.

Hypertensive response to exercise: a potential cause for new wall motion abnormality in the absence of coronary artery disease

OBJECTIVES

We sought to characterize patients with a hypertensive response during exercise echocardiography and its effect on results of the test.

BACKGROUND

A hypertensive response to exercise has been shown to cause false-positive results in perfusion imaging, radionuclide angiography and exercise electrocardiography, but its influence on exercise echocardiography has not been reported.

METHODS

We identified 548 of 6,686 patients who had coronary angiography within four weeks after exercise echocardiography from 1992 through 1996. Echocardiographic results from 132 patients (24%) with a hypertensive response to exercise, defined as systolic blood pressure (SBP) >220 mm Hg for men and SBP >190 mm Hg for women or as an increase in diastolic blood pressure (DBP) >10 mm Hg or DBP >90 mm Hg during exercise echocardiography, were compared with those from 416 patients without a hypertensive response.

RESULTS

Of 132 patients with a hypertensive response to exercise, 108 patients had exercise echocardiographic results positive for ischemia. Of these patients, 24 (22%) were found to have no significant coronary artery disease (CAD). In contrast, of 320 patients with positive exercise echocardiographic results without a hypertensive response, 39 (12%) patients did not have significant CAD. Among the false-positive results, new wall motion abnormalities were extensive in 15 of 24 (63%) hypertensive responders involving >25% of segments compared with 14 of 39 non-hypertensive responders (36%, p = 0.012).

CONCLUSIONS

An excessive rise in blood pressure during exercise is associated with a greater likelihood of new or worsening abnormalities with exercise, which may be observed in the absence of angiographically significant coronary artery stenosis.

Analysis of systolic and diastolic time intervals during dobutamine-atropine stress echocardiography: diagnostic potential of the Doppler myocardial performance index

Systolic and especially diastolic Doppler time intervals may be early markers of myocardial ischemia inducible by dobutamine-atropine stress echocardiography (DASE). We postulated that the Doppler myocardial performance index (MPI) may help differentiate ischemic from nonischemic responses. Hemodynamic and Doppler echocardiography variables were measured prospectively at every stress level of DASE in 32 patients (mean age 67 +/- 13 years). Adequate recordings were obtained in 27 patients; 13 had an ischemic response (group I) and 14 a nonischemic response (group II). Heart rate differed between groups at baseline. At equivalent peak stress, left ventricular wall motion score index was significantly greater and ejection fraction lower in group I patients. Of the Doppler variables, only the MPI consistently differed between groups, irrespective of the number of stress levels compared. The Doppler MPI may be a useful adjunct to wall motion analysis in the detection of myocardial ischemia during DASE.

Surgical management of left-sided carcinoid heart disease

BACKGROUND

Carcinoid involvement of left-sided heart valves has been reported in patients with a patent foramen ovale, carcinoid tumor of the lung, and active carcinoid syndrome with high levels of serotonin. The present study details the clinical features and surgical management of patients with carcinoid heart disease affecting both left- and right-sided valves.

METHODS AND RESULTS

Eleven patients (7 men, 4 women) with symptomatic carcinoid heart disease underwent surgery for left- and right-sided valve disease between 1989 and 1999. Mean age was 57+/-9 years, and median preoperative NYHA class was 3. All patients had metastatic carcinoid tumors and were on somatostatin analog. Of 11 patients, 5 (45%) had a patent foramen ovale; 1 of these also had a primary lung carcinoid tumor. Surgery included tricuspid valve replacement in all patients, pulmonary valve replacement in 3 and valvectomy in 7, mitral valve replacement in 6 and repair in 1, aortic valve replacement in 4 and repair in 2, CABG in 2, and patent foramen ovale closure in 5. One myocardial metastatic carcinoid tumor was removed. There were 2 perioperative deaths. At a mean follow-up of 41 months, 4 additional patients were dead. All but 1 surgical survivor initially improved >/=1 functional class. No patient required reoperation.

CONCLUSIONS

Carcinoid heart disease may affect left- and right-sided valves and occurred without intracardiac shunting in 55% of this surgical series. Despite metastatic disease that limits longevity, operative survivors had improvement in functional capacity. Cardiac surgery should be considered for select patients with carcinoid heart disease affecting left- and right-sided valves.

Contrast echocardiography improves the accuracy and reproducibility of left ventricular remodeling measurements: a prospective, randomly assigned, blinded study

OBJECTIVES

We sought to assess the impact of contrast injection and harmonic imaging, on the measure by echocardiography of left ventricular (LV) remodeling.

BACKGROUND

Left ventricular remodeling is a precursor of LV dysfunction, but the impact of contrast injection and harmonic imaging on the accuracy or reproducibility of echocardiography is unclear.

METHODS

We prospectively collected LV images by using simultaneous methods. Then, LV volumes were measured off-line, in blinded manner and in random order. The accuracy of echocardiography was determined in comparison to electron beam computed tomography (EBCT) in 26 patients. The reproducibility of echocardiography was assessed by three blinded observers with different training levels in 32 patients.

RESULTS

End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF), as measured by EBCT (195 +/- 55, 58 +/- 24 and 137 +/- 35 ml and 71 +/- 5%, respectively) and echocardiography with harmonic imaging and contrast injection (194 +/- 51, 55 +/- 20 and 140 +/- 35 ml and 72 +/- 4%, respectively), showed no differences (all p > 0.15) and excellent correlations (all r > 0.87). In contrast, echocardiography using harmonic imaging without contrast injection underestimated the EBCT results (all p < 0.01). Reproducibility was superior with rather than without contrast injection for intraobserver and interobserver variabilities (all p < 0.001). Values measured by different observers were different without contrast injection, but were similar with contrast injection (all p > 0.18). Consequently, intrinsic patient differences represented a larger and almost exclusive proportion of global variability with contrast injection for EDV (94 vs. 79%), ESV (93 vs. 82%), SV (87 vs. 53%) and EF (84 vs. 41%), as compared with harmonic imaging without contrast injection (all p < 0.005).

CONCLUSIONS

For assessment of LV remodeling, echocardiography with harmonic imaging and contrast injection improved the accuracy and reproducibility, as compared with imaging without contrast injection. With contrast injection, variability was almost exclusively due to intrinsic patient differences. Therefore, when evaluation of LV remodeling is deemed important, assessment after contrast injection should be the preferred echocardiographic approach.

Exercise echocardiography for the prognostic stratification of patients with low pretest probability of coronary artery disease

PURPOSE

The aim of this study was to determine whether exercise echocardiography provides incremental data for risk stratification of patients with a low pretest probability of coronary artery disease.

PATIENTS AND METHODS

The study included patients referred for exercise echocardiography whose probability of coronary artery disease was 25% or less. We calculated an exercise wall motion score index (on a 1-5 scale), an indicator of the extent and severity of exercise-induced abnormalities. The primary outcomes of the study were subsequent cardiac events (cardiac death and nonfatal myocardial infarction).

RESULTS

We studied 571 men and 1047 women; their mean (+/- SD) age was 55 +/- 13 years. During a median follow-up of 3 years, there were 19 cardiac events (6 cardiac deaths and 13 nonfatal myocardial infarctions); an additional 37 patients underwent coronary revascularization. In a multivariate analysis of clinical, exercise electrocardiographic, and echocardiographic parameters, exercise wall motion score index (hazard ratio [HR] = 2.1 per 0.5 units; 95% confidence interval [CI]: 1.3 to 3.4), and age (HR = 2.0 per decade; 95% CI: 1.2-2.8) were independently associated with the risk of cardiac events. Although exercise echocardiographic variables contributed significantly (P = 0.01) to a model of the risk of adverse events, only 9 (47%) of the 19 patients with cardiac events were identified by an abnormal exercise echocardiogram.

CONCLUSION

Among patients with low pretest probability of coronary artery disease by clinical criteria, exercise echocardiography identifies some, but not all, patients at risk of future events. Because of the low event rate, routine application of exercise echocardiography in a patient with a low pretest probability does not appear to be cost-effective and therefore cannot be recommended.

Utility of stress Doppler echocardiography in patients undergoing percutaneous mitral balloon valvotomy

A subset of patients with mitral stenosis have symptoms out of proportion to the resting hemodynamics. Exercise Doppler echocardiography is a useful diagnostic modality to determine which patients are limited by their valve obstruction and would therefore benefit from percutaneous mitral balloon valvotomy. We analyzed 11 patients who showed a peak exercise mean mitral gradient that doubled from baseline or a final gradient of > 15 mm Hg. The mean mitral gradient increased from 7 +/- 2 mm Hg at rest to 19 +/- 6 mm Hg (P < .001) with exercise. All patients reported improvement in symptoms of at least 1 functional class after valvotomy.

Contrast dobutamine stress echocardiography: clinical practice assessment in 300 consecutive patients

In this study we compared non-contrast imaging with contrast imaging of the left ventricle during dobutamine stress echocardiography (DSE). Wall segment visualization, image quality, and confidence of interpretation were determined with and without the use of intravenous Optison, a second-generation echocardiographic contrast agent, in 300 consecutive patients undergoing rest and peak DSE. At rest and at peak stress, the percentage of wall segments visualized, image quality, and confidence of interpretation were better with contrast compared with non-contrast imaging. No significant decrease was seen in wall segment visualization, image quality, or confidence of interpretation from rest to peak stress in images obtained with contrast, unlike the images obtained without contrast from rest to peak stress. The use of the intravenous echocardiographic contrast agent Optison during DSE significantly improved wall segment visualization and image quality at rest and at peak stress, resulting in improved confidence of interpretation.

Prognostic value of exercise echocardiography in patients after coronary artery bypass surgery

To assess the prognostic value of exercise echocardiography in patients with prior coronary artery bypass surgery, follow-up was obtained in 718 patients (591 men [82%] and 127 women [18%], aged 67 +/- 9 years) who underwent clinically indicated exercise echocardiography 5.7 +/- 4.7 years after coronary bypass surgery. Resting wall motion abnormalities were present in 479 patients (67%). New or worsening wall motion abnormalities developed with exercise in 366 patients (51%). During a median follow-up of 2.9 years, cardiac events included cardiac death in 36 patients and nonfatal myocardial infarction in 40 patients. The addition of the exercise echocardiographic variables, abnormal left ventricular end-systolic volume response and exercise ejection fraction to the clinical, resting echocardiographic and exercise electrocardiographic model provided incremental information in predicting cardiac events (chi-square 37 to chi-square 42, p = 0.02) and cardiac death (chi-square 38 to chi-square 43, p <0.02). Exercise echocardiography provides prognostic information in patients after coronary artery bypass surgery, incremental to clinical, rest echocardiographic, and exercise electrocardiographic variables.

Prognostic stratification of diabetic patients by exercise echocardiography

OBJECTIVES

The aim of this study was to assess the incremental value of exercise echocardiography for the risk stratification of diabetic patients.

BACKGROUND

There are currently insufficient outcome data in diabetic patients to define the role of stress echocardiography as a prognostic tool.

METHODS

We studied the prognostic value of exercise echocardiography in 563 patients with diabetes mellitus (mean age 64 +/- 11 years, 336 men) and known or suspected ischemic heart disease (IHD).

RESULTS

Cardiac events occurred in 50 patients (cardiac death in 23 and nonfatal myocardial infarction [MI] in 27) during a median follow-up period of three years. Event rate was lower in patients with normal as compared to those with abnormal exercise echocardiography at one year (0% vs. 1.9%), three years (1.8% vs. 11.9%), and five years (7.6% vs. 23.3%), respectively (p = 0.0001). Patients with multivessel distribution of echocardiographic abnormalities had the highest event rate (2.9% at one year, 15.2% at three years, and 32.8% at five years). In an incremental multivariate analysis model, exercise echocardiography increased the chi-square of the clinical and exercise ECG model from 29 to 44.8 (p = 0.0001).

CONCLUSIONS

Exercise echocardiography provides incremental data for risk stratification of diabetic patients with known or suspected IHD. Patients with a normal exercise echocardiogram have a low event rate. Patients with multivessel distribution of exercise echocardiographic abnormalities are at the highest risk of cardiac events, as one-third of these patients experience cardiac death or nonfatal MI during the five years following exercise echocardiography.

Prognostic value of exercise echocardiography in 2,632 patients > or = 65 years of age

OBJECTIVES

We sought to determine the prognostic value of exercise echocardiography in the elderly.

BACKGROUND

Limited data exist regarding the prognostic value of exercise testing in the elderly, a population which may be less able to exercise and is at increased risk of cardiac death.

METHODS

Follow-up (2.9 +/- 1.7 years) was obtained in 2,632 patients > or = 65 years who underwent exercise echocardiography.

RESULTS

There were 1,488 (56%) men and 1,144 (44%) women (age 72 +/- 5 years). The rest ejection fraction was 56 +/- 9%. Rest wall motion abnormalities were present in 935 patients (36%). The mean work load was 7.7 +/- 2.3 metabolic equivalents (METs) for men and 6.5 +/- 1.9 METs for women. New or worsening wall motion abnormalities developed with stress in 1,082 patients (41%). Cardiac events included cardiac death in 68 patients and nonfatal myocardial infarction in 80 patients. The addition of the exercise electrocardiogram to the clinical and rest echocardiographic model provided incremental information in predicting both cardiac events (chi-square = 77 to chi-square = 86, p = 0.003) and cardiac death (chi-square = 71 to chi-square = 86, p < 0.0001). The addition of exercise echocardiographic variables, especially the change in left ventricular end-systolic volume with exercise and the exercise ejection fraction, further improved the model in terms of predicting cardiac events (chi-square = 86 to chi-square = 108, p < 0.0001) and cardiac death (chi-square = 86 to chi-square = 99, p = 0.004).

CONCLUSIONS

Exercise echocardiography provides incremental prognostic information in patients > or = 65 years of age. The best model included clinical, exercise testing and exercise echocardiographic variables.

Diagnosis of pulmonary embolism with use of computed tomographic angiography

Pulmonary embolism (PE) is a common diagnostic problem, particularly in hospitalized patients. It remains a frequent cause of unexpected deaths. Traditionally, the diagnostic work-up for suspected PE has centered on the use of ventilation-perfusion (V-P) radionuclide lung scanning. However, V-P scanning does not provide adequate confirmation or exclusion of the diagnosis in the majority of patients who undergo this test. Although published guidelines advise further diagnostic testing after nondiagnostic V-P scans, clinicians infrequently perform such testing, and management decisions are commonly based on clinical judgment. In recent years, there has been an increasing interest in the use of computed tomographic (CT) angiography in the diagnostic evaluation of patients with suspected PE. Although there are unresolved issues regarding its sensitivity in detecting small peripheral emboli, CT angiography is more accurate than V-P scanning in the diagnosis of PE and yields other intrathoracic diagnoses. Herein we summarize the problems with the traditional approach centered on the use of V-P scanning in the diagnosis of PE and propose an alternative diagnostic strategy based primarily on the use of CT angiography.

A rapid stress-testing protocol for the detection of coronary artery disease: comparison of two-stage transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography

OBJECTIVES

We compared a new two-stage transesophageal atrial pacing stress echocardiography (TAPSE) protocol with a standard dobutamine stress echocardiography (DSE) protocol.

BACKGROUND

Transesophageal atrial pacing stress echocardiography has been proposed as an efficient alternative to DSE.

METHODS

Two-stage TAPSE (85% and 100% of age-predicted maximum heart rate) and DSE (5 to 40 microg/kg/min at 3-min stages with or without atropine) were both performed, in random sequence, in each patient of a study group of 36 patients. Regional wall-motion analysis, patient acceptance (1 = low, 5 = high), hemodynamics and duration for performing and interpreting tests were compared.

RESULTS

Transesophageal atrial pacing stress echocardiography was successful in 35 of the 36 patients (feasibility 97%). More TAPSE than DSE studies were called "ischemic" (37% vs. 14%; p = 0.005). Peak heart rate was higher with TAPSE (144 +/- 18 vs. 129 +/- 15 beats/min, p = 0.0001). Peak cardiac index (4.6 +/- 2.1 vs. 5.1 +/- 1.9 liters/min/m2, p = 0.14), patient acceptance score (4.2 +/- 0.7 vs. 3.8 +/- 1.3, p = 0.17) and study duration (14.2 +/- 9.3 vs. 13.3 +/- 3.3 min, p = 0.59) were similar. Recovery time (7.1 +/- 7.6 vs. 16.2 +/- 15.9 min, p = 0.0003) and interpretation time (9.1 +/- 2.8 vs. 13.5 +/- 4.4 min, p = 0.0001) were shorter for TAPSE than for DSE.

CONCLUSIONS

Two-stage TAPSE permits rapid evaluation of cardiac patients. Peak cardiac index and patient acceptance scores were similar for TAPSE and DSE. Ischemia was detected more often with TAPSE; this result was attributed to the higher peak heart rate obtained with this protocol.

Transthoracic Doppler echocardiographic comparison of left internal mammary grafts to left anterior descending coronary artery with ungrafted right internal mammary arteries in patients with and without myocardial ischemia by dobutamine stress echocardiography

To characterize Doppler flow patterns of the grafted left internal mammary artery (LIMA) in patients with and without dobutamine stress induced wall motion abnormalities in the graft distribution, we studied 29 patients who underwent coronary artery bypass surgery using LIMA grafts to the left anterior descending coronary artery (LAD). The ungrafted right internal mammary artery (RIMA) was used as a control. RIMA Doppler flow pattern was predominantly systolic in all patients. In patients without ischemia in the LAD distribution, LIMA flow was predominantly diastolic. In patients with ischemia, LIMA flow was predominantly systolic. In the grafted LIMA, a ratio of diastolic to systolic time-velocity integral of > 1.5 best showed absence of ischemia in the graft distribution. In summary, characterization of the Doppler flow pattern in the internal mammary arteries is feasible. In the grafted LIMA, ratios of diastolic to systolic flow are less in patients with an ischemic response in the subtended vascular bed than in those without ischemia.

Cardiology services after stress testing: are there sex differences? A population-based study

To test the hypothesis that, in a population-based cohort of persons undergoing stress tests, female sex was negatively associated with the use of cardiology visits in persons with no documented coronary artery disease (CAD) but that this association did not exist when CAD was established. Sex differences in the use of invasive cardiac procedures have been clearly documented, but data on physician encounters, an integral part of care, are lacking. A population-based cohort consisting of all Olmsted County, Minnesota residents who underwent an initial stress test in 1987, 1988, and 1989 in Olmsted County was examined. Medical records were reviewed for baseline characteristics including CAD diagnosis status, test results, and cardiology visits in the year following the stress test. Regression models were constructed to determine whether sex is independently associated with the probability of a visit. In the year after stress testing, there was no difference between the sexes in the use of inpatient (OR for female sex 0.88, 95% CI 0.62-0.97, P = 0.365) and outpatient/consultative (OR for female sex 1.24, 95% CI 0.95-1.61, P = 0.6) cardiology visits. Women were, however, less likely to receive preventive cardiology visits (OR for female sex 0.77, 95% CI 0.62-0.97, P = 0.02). This was largely related to less use of preventive visits among older women with documented coronary artery disease (CAD). In the absence of documented CAD, when the stress test was positive, women were less likely to receive preventive visits. In this geographically defined population within one year after an initial stress test, there was no sex difference in the use of in-patient or out-patient visits but women were less likely to receive preventive cardiology visits in the year after stress testing. Further studies are needed to understand the reasons for and impact of these care patterns.

Prognostic value of treadmill exercise testing in elderly persons

BACKGROUND

Recent exercise testing guidelines recognized a gap in knowledge about the prognostic value of treadmill exercise testing in elderly persons.

OBJECTIVE

To test the hypothesis that treadmill exercise testing has equal prognostic value among elderly (> or =65 years of age) and younger (<65 years of age) persons and to examine the incremental value of this testing over clinical data.

DESIGN

Inception cohort with a median follow-up of 6 years.

SETTING

Olmsted County, Minnesota.

PATIENTS

All elderly (n = 514) and younger (n = 2593) residents of Olmsted County who underwent treadmill exercise testing between 1987 and 1989.

MEASUREMENTS

Overall mortality and cardiac events (cardiac death, nonfatal myocardial infarction, and congestive heart failure).

RESULTS

Compared with younger patients, elderly patients had more comorbid conditions, achieved a lower workload (6.0 and 10.7 metabolic equivalents; P < 0.001), and had a greater likelihood of a positive exercise electrocardiogram (28% and 9%; P < 0.001). With median follow-up of 6 years, overall survival (63% and 92%; P < 0.001) and cardiac event-free survival (66% and 95%; P < 0.001) were worse among elderly persons than among younger persons. Workload was the only treadmill exercise testing variable associated with all-cause mortality in both age groups, and the strength of association was similar. Workload and angina with exercise testing were associated with cardiac events in both age groups, whereas a positive exercise electrocardiogram was associated with cardiac events only in younger persons (P < 0.05 for all comparisons). After adjustment for clinical variables, workload was the only additional treadmill exercise testing variable that was predictive of death (P < 0.001) and cardiac events (P < 0.05); the strength of the association was similar in both age groups. Each 1-metabolic equivalent increase in exercise capacity was associated with a 14% and 18% reduction in cardiac events among younger and elderly persons, respectively.

CONCLUSIONS

In elderly persons, treadmill exercise testing provided prognostic information that is incremental to clinical data. After adjustment for clinical factors, work-load was the only treadmill exercise testing variable that was strongly associated with outcome, and its prognostic effect was of the same magnitude in elderly and younger persons.

Assessment of cardiac risk before nonvascular surgery: dobutamine stress echocardiography in 530 patients

OBJECTIVE

This study evaluated the incremental value of dobutamine stress echocardiography (DSE) for assessment of cardiac risk before nonvascular surgery.

BACKGROUND

Limited information exists regarding the preoperative assessment of cardiac risk in patients with known or suspected coronary artery disease who are to undergo nonvascular surgery.

METHODS

All patients (303 men, 227 women) who underwent DSE before nonvascular surgery and did not sustain an intervening event (coronary revascularization or cardiac event) were studied. Clinical, electrocardiographic and rest and stress echocardiographic variables were evaluated to identify predictors of postoperative cardiac events.

RESULTS

Events occurred in 6% of patients: 1 cardiac death and 31 nonfatal myocardial infarctions. All of these patients had inducible ischemia on DSE (sensitivity 100%, specificity 63%). Multivariate predictors of postoperative events in patients with ischemia were history of congestive heart failure (p = 0.006; odds ratio = 4.66; confidence interval 1.55 to 14.02) and ischemic threshold less than 60% of age-predicted maximal heart rate (p = 0.0001; odds ratio 7.002; confidence interval 2.79 to 17.61). Clinical variables of Eagle's index identified 21% of patients as low, 68% as intermediate and 11% as high risk preoperatively; the postoperative event rates were 3%, 6%, and 14%, respectively. Dobutamine stress echocardiography identified 60% of patients as low (no ischemia), 32% as intermediate (ischemic threshold 60% or more) and 8% as high risk (ischemic threshold < 60%); postoperative event rates were 0%, 9% and 43%, respectively.

CONCLUSIONS

In this population of patients with known or suspected coronary artery disease evaluated before nonvascular surgery, DSE had incremental value over clinical, electrocardiographic and rest echocardiographic variables for identifying patients at low, intermediate and high risk for postoperative cardiac events. Ischemia occurring at less than 60% of age-predicted maximal heart rate identified patients at highest risk.

Impact of atropine injection on heart rate response during treadmill exercise echocardiography: a double-blind randomized pilot study

We evaluated the effect of atropine on the heart rate (HR) response during treadmill exercise echocardiography. A potential limitation of treadmill exercise echocardiography is the requirement for postexercise imaging. Rapid recovery of HR and wall motion abnormalities may decrease test sensitivity. A double-blind randomized study was performed at a tertiary care center. Fifty-two patients (age, 63 +/- 9 years) with known or suspected coronary artery disease were injected with either 0.5 mg of atropine or saline before treadmill exercise echocardiography. HR response during and after exercise was recorded. Atropine resulted in a greater increase in HR before exercise (increase of 15 +/- 9 vs 5 +/- 7 beats per minute, P < 0.0001) and a higher HR rate during the first 5 minutes of exercise (P < 0.05). In recovery, there was an exponential decrease in HR in both atropine and control groups. However, at the end of image acquisition (66 +/- 15 seconds), the HR was higher in the atropine group (128 +/- 21 vs 115 +/- 19 beats per minute, P = 0.02) and remained higher throughout the 10-minute recovery period (P = 0.0015). Dry mouth was more common after atropine injection (P = 0.005); other side effects were similar. The extent and resolution of myocardial ischemia were comparable in both groups. Atropine injection before treadmill exercise echocardiography results in a higher HR during the acquisition of echocardiographic images; whether atropine could affect the diagnostic accuracy of tread mill exercise echocardiography requires further study.

Early deterioration followed by improvement in contractility during dobutamine stress echocardiography: An unusual response

In 2 patients with severe proximal coronary artery stenosis and normal wall motion in this territory, we observed marked wall motion abnormalities with low and intermediate doses of dobutamine, followed by marked improvement with continued dobutamine infusion. This unusual response suggests ischemic preconditioning and recruitment of coronary collaterals and would be recognized only by monitoring of images obtained at all stages of dobutamine infusion.

Harmonic imaging: echocardiographic enhanced contrast intensity and duration

The intensity and duration of contrast effect within the left ventricular cavity after an intravenous bolus of Levovist Injection were observed with both harmonic and fundamental imaging in nine patients with known or suspected coronary artery disease. Contrast intensity was assessed by a qualitative grading system (0, none; 1, weak; 2, moderate; 3, good) and by videodensitometric analysis of pixel intensity. Duration of left ventricular contrast effect was determined by measuring time from the initial visual appearance of contrast agent to its disappearance. The mean increase in pixel intensity within the left ventricular cavity from precontrast to peak contrast was significantly greater for second harmonic than for fundamental imaging (25.5 vs 7.1; P < 0.012). The mean contrast intensity qualitative score with harmonic imaging was higher (2.6 +/- 0.73 vs 1.2 +/- 0.44; P < 0.01) and the duration of contrast effect was longer (242 +/- 131 s vs 53 +/- 33 s; P < 0.004). Second harmonic imaging significantly enhanced contrast intensity and prolonged visible duration of contrast effect after a peripheral venous injection of Levovist.

Nonexercise stress transthoracic echocardiography: transesophageal atrial pacing versus dobutamine stress

OBJECTIVES

To compare transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography for feasibility, safety, duration, patient acceptance and concordance in inducing wall motion abnormalities.

BACKGROUND

Transesophageal atrial pacing is an effective method of increasing heart rate and has been used in the assessment of coronary artery disease.

METHODS

Both tests were performed in sequence on the same patients in random order. Transesophageal atrial pacing stress echocardiography began at a heart rate of 10 beats/min above the baseline value and was increased by 20 beats/min every two min until 85% of the age-predicted maximum heart rate or another end point was reached. Dobutamine echocardiography was performed using three-min stages and a maximum dose of 40 microg/kg per min. Atropine (total dose < or =2 mg) was administered at the start of the 40 microg/kg per min stage if needed to augment heart rate or during pacing if Wenckebach heart block occurred.

RESULTS

Transesophageal atrial pacing stress echocardiography was feasible in 100 of 104 patients (96%); the duration (8.6+/-3.6 min) was significantly shorter than that of dobutamine stress echocardiography (15.1+/-3.9 min) (p = 0.0001). With transesophageal atrial pacing stress echocardiography, the recovery period was shorter, symptoms and dysrhythmias were fewer, hypertension and hypotension were less common and target heart rate was more frequently achieved. No complications occurred with either test. Patient acceptance was satisfactory. Agreement between results of both tests was good for segmental wall motion scoring with a 16-segment model, scores 1 to 5 (kappa: rest, 0.79; peak, 0.57) and test interpretation (normal, ischemia, infarction or resting wall motion abnormality with ischemia) (kappa: 0.77).

CONCLUSIONS

Transesophageal atrial pacing stress echocardiography is a feasible, well-tolerated alternative to dobutamine stress echocardiography. It can be performed rapidly and shows good agreement with dobutamine stress echocardiography in the induction of myocardial ischemia.

Prognostic value of treadmill exercise testing: a population-based study in Olmsted County, Minnesota

BACKGROUND

The prognostic value of treadmill exercise testing (TMET) has been studied in selected populations. The generalizability of these data to different populations and to women is uncertain.

METHODS AND RESULTS

A retrospective, population-based cohort study of all persons (1452 men and 741 women) who underwent TMET in years 1987 to 1989 in Olmsted County, Minnesota, was undertaken. Individuals were followed up for all-cause mortality and cardiac events (cardiac deaths, nonfatal myocardial infarction, or congestive heart failure). Sex-specific analyses were performed to determine whether the predictors of outcome and the magnitude of the associations were similar in both sexes. In men, 77 deaths and 106 cardiac events occurred during 8956 person-years of observation; in women, 46 deaths and 54 cardiac events occurred during 4801 person-years of follow-up. Exercise-induced angina, ECG changes, and workload achieved on the TMET were strongly associated with all-cause mortality and cardiac events in both sexes, and the strength of the association was similar. After adjustment, workload was the only TMET variable associated with outcome. A higher workload was associated with a reduction in the risk of cardiac events and of all-cause mortality; the protective effect of exercise capacity was strong and was similar in both sexes.

CONCLUSIONS

In this population-based cohort, exercise capacity was the TMET variable that exhibited the strongest association with all-cause mortality and cardiac events. This protective effect of exercise capacity was observed in both sexes.

Dobutamine stress Doppler hemodynamics in patients with aortic stenosis: feasibility, safety, and surgical correlations

OBJECTIVES

This study was designed to describe the experience of our center with the safety and feasibility of dobutamine stress echocardiography (DSE) in aortic stenosis (AS), to characterize the hemodynamic response to dobutamine infusion, and to examine the hemodynamic response in relation to the anatomic evaluation of the valve among patients who underwent valve replacement.

BACKGROUND

The diagnosis of the hemodynamic severity of AS can be difficult when the cardiac output is reduced and the gradient is low, but the effective valve area calculates to be small. DSE has been proposed as a means of assessing the severity of AS in this setting.

METHODS

We reviewed 27 patients (18 men, 9 women; mean age 71 +/- 12 years) with AS who underwent DSE between 1991 and 1996.

RESULTS

Fifteen (55%) patients were New York Heart Association class III or IV, 8 (30%) had angina Canadian class III or IV, and 3 (11%) syncope. Dobutamine peak dose was 27 +/- 11 micrograms/kg/min. Sixteen (59%) patients had mild side effects. DSE resulted in a significant increase in the cardiac output from 4.1 +/- 1.2 L/min at rest to 7.3 +/- 1.9 L/min at peak dose, and in heart rate (76 +/- 16 beats/min to 124 +/- 20 beats/min), systolic blood pressure (128 +/- 26 mm Hg to 137 +/- 26 mm Hg), ejection fraction (38% +/- 20% to 42% +/- 20%), and transvalvular mean gradient (28 +/- 10 mm Hg to 39 +/- 9 mm Hg) (P <.05). There was also a significant increase in the valve area from 0.77 +/- 0.14 cm2 at rest to 0.97 +/- 0.21 cm2 (P <.001). Seven patients underwent surgery; all valves were severely calcified, confirming anatomic disease. In this group, an increase in the mean gradient but also a trend toward an increase in the valve area were noted in response to dobutamine: 33 +/- 10 mm Hg to 47 +/- 6 mm Hg and 0.79 +/- 0.11 cm2 to 0.95 +/- 0.19 cm2, respectively.

CONCLUSION

Although more data are needed to fully establish the safety of the test in this indication, this study suggests that patients with AS can safely undergo DSE. Dobutamine results in an increase not only in the mean gradient, but also in the valve area. An increase in valve area with dobutamine was observed in some patients with anatomically confirmed severe AS and thus does not exclude fixed valve disease.

Chronotropic response, safety, and accuracy of dobutamine stress echocardiography in patients with atrial fibrillation and known or suspected coronary artery disease

Ninety-two consecutive patients with atrial fibrillation (AF) who underwent dobutamine stress echocardiography were compared with a control group of patients in sinus rhythm matched for age, sex, and resting heart rate. Patients with AF had an increased chronotropic response to dobutamine, but there were no adverse effects and no evidence that the lower doses of dobutamine typically given to patients with AF were insufficient to induce ischemia.

The safety of treadmill exercise stress testing in patients with abdominal aortic aneurysms

BACKGROUND

Exercise stress testing in patients with abdominal aortic aneurysms may cause enlargement or rupture of aneurysms.

OBJECTIVE

To evaluate the safety of treadmill exercise stress testing in patients with abdominal aortic aneurysms.

DESIGN

Retrospective descriptive study.

SETTING

Tertiary care center.

PATIENTS

262 patients who had abdominal aortic aneurysms more than 4 cm in diameter and underwent treadmill exercise stress testing.

MEASUREMENTS

Pain after stress testing, rupture of the aneurysm or death, aneurysm size, and exercise stress test results.

RESULTS

The average aneurysm diameter was 5.5 +/- 1.1 cm. One patient with a 6.1-cm aneurysm was found to have a contained rupture 12 hours after stress testing. The event rate for aneurysm rupture was 0.4% (95% CI, 0.0% to 2.1%). No deaths or other negative outcomes were documented.

CONCLUSION

Despite theoretical concerns, exercise stress testing of patients with abdominal aortic aneurysms seems to be safe and is associated with a low incidence of acute adverse events.

Clinical recognition of pulmonary embolism: problem of unrecognized and asymptomatic cases

Dyspnea, pleuritic chest pain, and tachypnea are widely appreciated as common initial features of pulmonary embolism (PE). This knowledge is derived primarily from prospective studies evaluating diagnostic tests or therapeutic interventions in which the study patients are suspected to have PE based on their initial symptoms. Autopsy studies, however, continue to show that most cases of fatal PE are unrecognized and undiagnosed. Data from studies screening for PE in patients with deep venous thrombosis and in postoperative patients suggest that many patients with PE are asymptomatic and that PE is unrecognized. We believe that the current concepts regarding the initial clinical features of PE are too narrow and biased toward symptomatic cases. High clinical suspicion may be insufficient in recognizing PE. Herein we summarize the available data and explore the implications for clinical practice.

Dobutamine effect on ankle-brachial pressure index in patients with peripheral arterial occlusive disease. New noninvasive test for evaluation of peripheral circulation?

BACKGROUND

This study was designed to evaluate the effect of short-term administration of graded dose of dobutamine on the circulation of the lower limbs in the patients with symptomatic peripheral arterial occlusive disease.

METHODS

An ankle-brachial pressure index (ABI) was determined at the time of dobutamine stress echocardiography by measuring systolic pressure over the brachial artery and right dorsalis pedis artery using continuous-wave Doppler instrument. Setting. The study was conducted on all patients who had dobutamine stress echocardiography ordered by their referring physicians and performed in the Echocardiography Laboratory of the Mayo Clinic. Patients. All patients scheduled for dobutamine stress echocardiography were the subject of this study unless they had rigid vessels defined as ABI > 1.5, were on beta-blockers or did not agree to participate in the study. 20 patients, mean age 67 +/- 9 years (9 men and 11 women) without peripheral occlusive arterial disease and resting ABI > or = 1.0 (group A), and 18 patients, mean age 71 +/- 10 years (11 men and 7 women) with the evidence of peripheral occlusive arterial disease and ABI < 1.0 were examined. Measures. ABI was measured just prior to starting the dobutamine infusion, and then at the third minute of each increment in dobutamine dosage.

RESULTS

In control group patients ABI rises at 5-10 micrograms/kg/min of dobutamine infusion and at higher doses (20-50 micrograms/kg/min) drops back to the baseline values. In the patients with peripheral arterial occlusive disease low doses of dobutamine do not increase ABI, but higher doses cause decrease of pressure index from 0.6 to 0.3. There was no incidence of ischemic pain or any other kind of discomfort in the lower extremities.

CONCLUSIONS

Low doses of dobutamine have no decremental effect on peripheral circulation. High doses of dobutamine cause a profound decrease of blood pressure in the lower limbs of patients with peripheral occlusive arterial disease, and the extent of decrease was proportional to the degree of ischemia. Peripheral blood pressure changes registered in the study over dorsalis pedis artery at the time of dobutamine infusion resemble those that occurred at the time of exercise-walking test. ABI measurement at the time of dobutamine echocardiography might be a useful test for the evaluation of peripheral circulation. Further studies are necessary for the assessment of a clinical usefulness of dobutamine-ankle-brachial test.