Prognostic Significance of Elevated Left Ventricular Filling Pressures with Exercise: Insights from a Cohort of 14,338 Patients

BACKGROUND

Exercise echocardiography can assess for cardiovascular causes of dyspnea other than coronary artery disease. However, the prevalence and prognostic significance of elevated left ventricular (LV) filling pressures with exercise is understudied.

METHODS

We evaluated 14,338 patients referred for maximal symptom-limited treadmill echocardiography. In addition to assessment of LV regional wall motion abnormalities (RWMAs), we measured patients' early diastolic mitral inflow (E), septal mitral annulus relaxation (e'), and peak tricuspid regurgitation velocity before and immediately after exercise.

RESULTS

Over a mean follow-up of 3.3 ± 3.4 years, patients with E/e' ≥15 with exercise (n = 1,323; 9.2%) had lower exercise capacity (7.3 ± 2.1 vs 9.1 ± 2.4 metabolic equivalents, P < .0001) and were more likely to have resting or inducible RWMAs (38% vs 18%, P < .0001). Approximately 6% (n = 837) had elevated LV filling pressures without RWMAs. Patients with a poststress E/e' ≥15 had a 2.71-fold increased mortality rate (2.28-3.21, P < .0001) compared with those with poststress E/e' ≤ 8. Those with an E/e' of 9 to 14, while at lower risk than the E/e' ≥15 cohort (hazard ratio [HR] = 0.58 [0.48-0.69]; P < .0001), had higher risk than if E/e' ≤8 (HR = 1.56 [1.37-1.78], P < .0001). On multivariable analysis, adjusting for age, sex, exercise capacity, LV ejection fraction, and presence of pulmonary hypertension with stress, patients with E/e' ≥15 had a 1.39-fold (95% CI, 1.18-1.65, P < .0001) increased risk of all-cause mortality compared with patients without elevated LV filling pressures. Compared with patients with E/e' ≤ 15 after exercise, patients with E/e' ≤15 at rest but elevated after exercise had a higher risk of cardiovascular death (HR = 8.99 [4.7-17.3], P < .0001).

CONCLUSION

Patients with elevated LV filling pressures are at increased risk of death, irrespective of myocardial ischemia or LV systolic dysfunction. These findings support the routine incorporation of LV filling pressure assessment, both before and immediately following stress, into the evaluation of patients referred for exercise echocardiography.

Incidence of Severe Adverse Drug Reactions to Ultrasound Enhancement Agents in a Contemporary Echocardiography Practice

OBJECTIVES

Prior data indicate a very rare risk of serious adverse drug reaction (ADR) to ultrasound enhancement agents (UEAs). We sought to evaluate the frequency of ADR to UEA administration in contemporary practice.

METHODS

We retrospectively reviewed 4 US health systems to characterize the frequency and severity of ADR to UEA. Adverse drug reactions were considered severe when cardiopulmonary involvement was present and critical when there was loss of consciousness, loss of pulse, or ST-segment elevation. Rates of isolated back pain and headache were derived from the Mayo Clinic Rochester stress echocardiography database where systematic prospective reporting of ADR was performed.

RESULTS

Among 26,539 Definity and 11,579 Lumason administrations in the Mayo Clinic Rochester stress echocardiography database, isolated back pain or headache was more frequent with Definity (0.49% vs 0.04%, P < .0001) but less common with Definity infusion versus bolus (0.08% vs 0.53%, P = .007). Among all sites there were 201,834 Definity and 84,943 Lumason administrations. Severe and critical ADR were more frequent with Lumason than with Definity (0.0848% vs 0.0114% and 0.0330% vs 0.0010%, respectively; P < .001 for each). Among the 3 health systems with >2,000 Lumason administrations, the frequency of severe ADR with Lumason ranged from 0.0755% to 0.1093% and the frequency of critical ADR ranged from 0.0293% to 0.0525%. Severe ADR rates with Definity were stable over time but increased in more recent years with Lumason (P = .02). Patients with an ADR to Lumason since the beginning of 2021 were more likely to have received a COVID-19 vaccination compared with matched controls (88% vs 75%; P = .05) and more likely to have received Moderna than Pfizer-Biotech (71% vs 26%, P < .001).

CONCLUSION

Severe and critical ADR, while rare, were more frequent with Lumason, and the frequency has increased in more recent years. Additional work is needed to better understand factors, including associations with recently developed mRNA vaccines, which may be contributing to the increased rates of ADR to UEA since 2021.

Identification and risk stratification of coronary disease by artificial intelligence-enabled ECG

Background

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death worldwide, driven primarily by coronary artery disease (CAD). ASCVD risk estimators such as the pooled cohort equations (PCE) facilitate risk stratification and primary prevention of ASCVD but their accuracy is still suboptimal.

Methods

Using deep electronic health record data from 7,116,209 patients seen at 70+ hospitals and clinics across 5 states in the USA, we developed an artificial intelligence-based electrocardiogram analysis tool (ECG-AI) to detect CAD and assessed the additive value of ECG-AI-based ASCVD risk stratification to the PCE. We created independent ECG-AI models using separate neural networks including subjects without known history of ASCVD, to identify coronary artery calcium (CAC) score ≥300 Agatston units by computed tomography, obstructive CAD by angiography or procedural intervention, and regional left ventricular akinesis in ≥1 segment by echocardiogram, as a reflection of possible prior myocardial infarction (MI). These were used to assess the utility of ECG-AI-based ASCVD risk stratification in a retrospective observational study consisting of patients with PCE scores and no prior ASCVD. The study period covered all available digitized EHR data, with the first available ECG in 1987 and the last in February 2023.

Findings

ECG-AI for identifying CAC ≥300, obstructive CAD, and regional akinesis achieved area under the receiver operating characteristic (AUROC) values of 0.88, 0.85, and 0.94, respectively. An ensembled ECG-AI identified 3, 5, and 10-year risk for acute coronary events and mortality independently and additively to PCE. Hazard ratios for acute coronary events over 3-years in patients without ASCVD that tested positive on 1, 2, or 3 versus 0 disease-specific ECG-AI models at cohort entry were 2.41 (2.14-2.71), 4.23 (3.74-4.78), and 11.75 (10.2-13.52), respectively. Similar stratification was observed in cohorts stratified by PCE or age.

Interpretation

ECG-AI has potential to address unmet need for accessible risk stratification in patients in whom PCE under, over, or insufficiently estimates ASCVD risk, and in whom risk assessment over time periods shorter than 10 years is desired.

Funding

Anumana.

The feasibility and value of assessing patient reported outcomes in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that negatively impacts health‐related quality of life (HRQOL). The PAH‐symptoms and impact (PAH‐SYMPACT) questionnaire is a validated disease‐specific patient‐reported outcome (PRO) instrument that assesses a patient's symptoms and the impact of PAH and its treatment on well‐being. We performed a single‐center prospective cohort study of patients with PAH to determine the feasibility of assessing PROs in clinical practice and to determine the association between PAH‐SYMPACT domains and clinical characteristics and outcomes. One hundred and ten patients completed the 1‐day version of the PAH‐SYMPACT questionnaire which consists of 22 Likert‐scale questions that assess HRQOL across four domains: cardiopulmonary (CP) symptoms, cardiovascular (CV) symptoms, physical impact (PI), and cognitive and emotional (CE) impact. Higher scores indicate worse HRQOL. Patients were predominantly female (n = 86, 78%) with a mean age of 57.8 ± 16.2 years. While several patient characteristics were associated with CP and PI domains, few were associated with CV and CE domains. PI and CE impact scores were associated with recent hospitalizations and mortality and CE impact score was independently associated with an increased risk of death after adjustment for disease severity (hazard ratio: 3.29, 95% confidence interval: 1.56–6.91, p = 0.002). In conclusion, the assessment of PROs in clinical practice using the PAH‐SYMPACT questionnaire is both feasible and valuable. PAH‐SYMPACT scores have independent prognostic value and are not adequately reflected by traditional measures of disease severity. These findings underscore the importance of assessing HRQOL in clinical practice.

High Prevalence of Severe Aortic Stenosis in Low-Flow State Associated With Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is a low-flow state and may underestimate aortic stenosis (AS) severity. Single-high Doppler signals (HS) consistent with severe AS (peak velocity ≥4 m/s or mean gradient ≥40 mm Hg) are averaged down in current practice. The objective for the study was to determine the significance of HS in AF low-gradient AS (LGAS).

METHODS

One thousand five hundred forty-one patients with aortic valve area ≤1 cm² and left ventricular ejection fraction ≥50% were identified and classified as high-gradient AS (HGAS) (≥40 mm Hg) and LGAS (<40 mm Hg), and AF versus sinus rhythm (SR). Available computed tomography aortic valve calcium scores (AVCS) were retrieved from the medical record. Outcomes were assessed.

RESULTS

Mean age was 76±11 years, female 47%. Mean gradient was 51±12 in SR-HGAS, 48±10 in AF-HGAS, 31±5 in SR-LGAS, and 29±7 mm Hg in AF-LGAS, all P≤0.001 versus SR-HGAS; HS were present in 33% of AF-LGAS. AVCS were available in 34%. Compared with SR-HGAS (2409 arbitrary units; interquartile range, 1581-3462) AVCS were higher in AF-HGAS (2991 arbitrary units; IQR1978-4229, P=0.001), not different in AF-LGAS (2399 arbitrary units; IQR1817-2810, P=0.47), and lower in SR-LGAS (1593 arbitrary units; IQR945-1832, P<0.001); AVCS in AF-LGAS were higher when HS were present (P=0.048). Compared with SR-HGAS, the age-, sex-, comorbidity index-, and time-dependent aortic valve replacement-adjusted mortality risk was higher in AF-HGAS (hazard ratio=1.82 [1.40-2.36], P<0.001) and AF-LGAS with HS (hazard ratio=1.54 [1.04-2.26], P=0.03) but not different in AF-LGAS without HS or SR-LGAS (both P=not significant).

CONCLUSIONS

Severe AS was common in AF-LGAS. AVCS in AF-LGAS were not different from SR-HGAS. AVCS were higher and mortality worse in AF-LGAS when HS were present.

Prognostic value of peak stress cardiac power in patients with normal ejection fraction undergoing exercise stress echocardiography

AIMS

Cardiac power is a measure of cardiac performance that incorporates both pressure and flow components. Prior studies have shown that cardiac power predicts outcomes in patients with reduced left ventricular (LV) ejection fraction (EF). We sought to evaluate the prognostic significance of peak exercise cardiac power and power reserve in patients with normal EF.

METHODS AND RESULTS

We performed a retrospective analysis in 24 885 patients (age 59 ± 13 years, 45% females) with EF ≥50% and no significant valve disease or right ventricular dysfunction, undergoing exercise stress echocardiography between 2004 and 2018. Cardiac power and power reserve (developed power with stress) were normalized to LV mass and expressed in W/100 g of LV myocardium. Endpoints at follow-up were all-cause mortality and diagnosis of heart failure (HF). Patients in the higher quartiles of power/mass (rest, peak stress, and power reserve) were younger and had higher peak blood pressure and heart rate, lower LV mass, and lower prevalence of comorbidities. During follow-up [median 3.9 (0.6-8.3) years], 929 patients died. After adjusting for age, sex, metabolic equivalents (METs) achieved, ischaemia/infarction on stress test results, medication, and comorbidities, peak stress power/mass was independently associated with mortality [adjusted hazard ratio (HR), highest vs. lowest quartile, 0.5, 95% confidence interval (CI) 0.4-0.6, P < 0.001] and HF at follow-up [adjusted HR, highest vs. lowest quartile, 0.4, 95% CI (0.3, 0.5), P < 0.001]. Power reserve showed similar results.

CONCLUSION

The assessment of cardiac power during exercise stress echocardiography in patients with normal EF provides valuable prognostic information, in addition to stress test findings on inducible myocardial ischaemia and exercise capacity.

Impact of Anemia on Exercise and Pharmacologic Stress Echocardiography

BACKGROUND

The safety and diagnostic accuracy of stress testing in anemic patients have not been well studied. Despite a lack of data, significant anemia may be considered a relative contraindication to stress testing because of safety concerns related to insufficient myocardial oxygen supply.

METHODS

The authors reviewed 28,829 consecutive patients with blood hemoglobin drawn within 48 hours of stress echocardiography (15,624 exercise and 13,205 dobutamine). The associations of blood hemoglobin concentration with arrhythmia and other stress echocardiographic findings were examined. Additionally, the effect of anemia on the positive predictive value of stress echocardiography for the detection of significant coronary artery stenosis (≥50%) was assessed in patients who subsequently underwent coronary angiography.

RESULTS

Anemia was present in 6,401 patients (22.2%) and was severe (hemoglobin < 8.0 g/dL) in 52. Stress testing with either exercise or dobutamine was safe, with no significant increase in serious arrhythmia events or need for hospitalization. In the exercise cohort, worsening anemia was associated with reduced treadmill exercise time, lower peak heart rate, peak rate-pressure product, and achieved workload. In the dobutamine stress cohort, worsening anemia was associated with higher resting heart rate, more use of atropine, and fewer patients attaining target heart rate. The positive predictive value of stress echocardiography was higher in patients with moderate anemia compared with those without anemia (71.8% vs 60.2%, P = .01).

CONCLUSIONS

This study demonstrates that stress testing is safe in patients with mild and moderately anemia, albeit with a small increase in mild supraventricular arrhythmias with exercise. However, worsening anemia was associated with a significant reduction in exercise capacity. Additionally, worsening anemia was associated with an improvement in the positive predictive value of stress echocardiography. Extrapolation of these data to patients with severe anemia should be performed with caution given the limited number of patients with severe anemia in this study.

Preoperative Dobutamine Stress Echocardiography and Clinical Factors for Assessment of Cardiac Risk after Noncardiac Surgery

BACKGROUND

The role of dobutamine stress echocardiography (DSE) in the risk stratification of patients undergoing noncardiac surgery in the current era is unclear. The aim of this study was to evaluate the yield of DSE and the additive role of DSE to clinical criteria for preoperative risk stratification of patients undergoing noncardiac surgery.

METHODS

The study included 4,494 patients undergoing DSE ≤90 days before noncardiac surgery. The primary outcome was a composite of postoperative myocardial infarction, cardiac arrest, and all-cause mortality ≤30 days after noncardiac surgery.

RESULTS

The overall 30-day postoperative cardiac event rate was 2.3%. The mortality rate was 0.9% overall and 0.7% and 1.3% after normal and abnormal results on DSE, respectively. Among clinical variables, the modified Revised Cardiac Risk Index score demonstrated the strongest association with postoperative risk (P < .001). Patients with Revised Cardiac Risk Index scores of ≥3 had an event rate of 7.5%. The event rates for patients with wall motion score index ≥1.7 at baseline, left ventricular ejection fractions <40% at peak stress, or ischemic thresholds <70% of age-predicted maximal heart rate were 7.1%, 8.6%, and 7.9%, respectively. After adjusting for clinical variables, the overall result of DSE (P < .001), baseline and peak-stress wall motion score index (P < .001 and P = .014, respectively), peak-stress left ventricular ejection fraction (P < .001), and the number of ischemic segments (P = .027) were all associated with postoperative cardiac events. Incremental multivariate analysis demonstrated that an overall abnormal result on DSE, added to clinical variables, was associated with an increased risk for postoperative cardiac events (odds ratio, 2.07; 95% CI, 1.35-3.17; P < .001).

CONCLUSIONS

Baseline and peak-stress findings on preoperative DSE add to the prognostic utility of clinical variables for stratifying cardiac risk after noncardiac surgery.

Atrial fibrillation is not an independent predictor of outcome in patients with aortic stenosis

OBJECTIVES

To examine the prognostic significance of atrial fibrillation (AF) versus sinus rhythm (SR) on the management and outcomes of patients with severe aortic stenosis (AS).

METHODS

1847 consecutive patients with severe AS (aortic valve area ≤1.0 cm² and aortic valve systolic mean Doppler gradient ≥40 mm Hg or peak velocity ≥4 m/s) and left ventricular ejection fraction ≥50% were identified. The independent association of AF and all-cause mortality was assessed.

RESULTS

Age was 76±11 years and 46% were female; 293 (16%) patients had AF and 1554 (84%) had SR. In AF, 72% were symptomatic versus 71% in SR. Survival rate at 5 years for AF (41%) was lower than SR (65%) (age- and sex-adjusted HR=1.66 (1.40-1.98), p<0.0001). In multivariable analysis, factors associated with mortality included age (HR per 10 years=1.55 (1.42-1.69), p<0.0001), dyspnoea (HR=1.58 (1.33-1.87), p<0.0001), ≥ moderate mitral regurgitation (HR=1.63 (1.22-2.18), p=0.001), right ventricular systolic dysfunction (HR=1.88 (1.52-2.33), p<0.0001), left atrial volume index (HR per 10 mL/m²=1.13 (1.07-1.19), p<0.0001) and aortic valve replacement (AVR) (HR=0.44 (0.38-0.52), p<0.0001). AF was not a predictor of mortality independent of variables strongly correlated HR=1.02 (0.84-1.25), p=0.81). The 1-year probability of AVR following diagnosis of severe AS was lower in AF (49.8%) than SR (62.5%) (HR=0.73 (0.62-0.86), p<0.001); among patients with AF not referred for AVR, symptoms were frequently attributed to AF instead of AS.

CONCLUSION

AF was associated with poor prognosis in patients with severe AS, but apparent differences in outcomes compared with SR were explained by factors other than AF including concomitant cardiac abnormalities and deferral of AVR due to attribution of cardiac symptoms to AF.

Thrombocytopenia independently predicts death in idiopathic PAH

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive vascular disorder with a high mortality. Clinical experience and small case series suggest thrombocytopenia may be frequent in this population and associated with a poor prognosis. We sought to estimate the prevalence of thrombocytopenia in patients with PAH and characterize its association with disease characteristics and patient outcome.

METHODS

Single center cohort study of 714 incident adult patients with Group 1 PH who were evaluated for baseline platelet count at the time of diagnosis. Pts were stratified into three groups: normal platelet count (>150 × 10⁹/L), Grade 1 thrombocytopenia (75-149 × 10⁹/L) and Grade 2-4 thrombocytopenia (<75 × 10⁹/L).

RESULTS

The median platelet count was 209 × 10⁹/L (IQR 163, 264). There were 572 (80%) pts without thrombocytopenia, 107 (15%) with Grade 1 and 35 (5%) with Grade 2-4 thrombocytopenia. The median pt age was 55 years (IQR 44-65) with no difference between platelet groups (p = 0.85). Men were more likely to have thrombocytopenia (62, 34%) than women (80, 15%, p < 0.0001). Thrombocytopenia was frequent with portopulmonary PAH (84%) as opposed to idiopathic PAH (iPAH; 14%) or connective tissue disease associated PAH (12%). Platelet counts were not associated with functional class symptoms, the degree of right ventricular enlargement or dysfunction or tricuspid regurgitation by echocardiography. Invasive hemodynamics of right atrial pressure, mean pulmonary artery pressure and pulmonary vascular resistance were also similar between platelet groups. Thrombocytopenia was associated with higher mortality in iPAH patients (age- and sex-adjusted 5 year mortality [HR 1.95 (1.20, 3.08) p = 0.008] but not in other etiology groups. In a multivariate model of iPAH patients (adjusted for age, sex, DLCO, PVR, creatinine and 6MW distance) thrombocytopenia was most predictive of 5-year mortality [HR 1.68 (1.32, 2.12), p < 0.0001].

CONCLUSION

Thrombocytopenia in the context of iPAH portends a poor prognosis and is a simple independent factor to consider in judging severity of disease.

Frequency, Predictors, and Implications of Abnormal Blood Pressure Responses During Dobutamine Stress Echocardiography

BACKGROUND

It is not known whether abnormal blood pressure (BP) responses during dobutamine stress echocardiography (DSE) are associated with abnormal test results, nor if such results indicate obstructive coronary artery disease (CAD). We sought to define the frequency of abnormal BP responses during DSE and their impact on accuracy of test results.

METHODS AND RESULTS

We studied 21 949 patients who underwent DSE at Mayo Clinic, Rochester, MN, grouped by peak systolic BP achieved during the test. We also analyzed a subgroup who underwent coronary angiography within 30 days after positive DSE. The positive predictive value of DSE was calculated for each BP group. Patients with hypertensive response (n=1905; 9%) were more likely to have positive DSE than those with normal (n=19 770; 90%) or hypotensive (n=274; 1%) BP responses (32% versus 21% versus 23%, respectively; P<0.0001). Angiography, performed in 1126 patients, showed obstructive CAD (≥50% stenosis) in 814 patients and severe CAD (≥70% stenosis) in 708 patients. Positive predictive value of DSE was similar for patients who had hypertensive and normal BP responses (69% versus 73%; P=0.3), considering 50% stenosis cut point. The proportion of severe CAD (≥70% stenosis) was lower in patients who had hypertensive response compared with those who had normal BP response (54% versus 65%; P=0.005).

CONCLUSIONS

Patients with hypertensive response during DSE are more likely to have stress-induced myocardial ischemia compared with those with normal or hypotensive BP responses but are not more likely to have false-positive DSE results. They are, however, less likely to have higher grade or multivessel CAD.

Dobutamine Stress Echocardiography: Impact of Abnormal Blood Potassium Levels on Cardiac Arrhythmias

BACKGROUND

Guidelines suggest that an abnormal blood potassium level is a relative contraindication to performing dobutamine stress echocardiography (DSE). However, this has not been previously studied.

METHODS

We reviewed a consecutive series of patients who had potassium testing within 48 hours of undergoing DSE for the evaluation of myocardial ischemia over a 10-year period (N = 13,198). Normal potassium range in our laboratory is 3.6-5.2 mmol/L. Hemolyzed samples were not included. The association of potassium levels with the development of supraventricular and ventricular arrhythmias was assessed.

RESULTS

The incidence of clinically significant arrhythmias was very low (supraventricular tachycardia/atrial fibrillation, 4.9%; nonsustained ventricular tachycardia, 2.9%; sustained ventricular tachycardia or ventricular fibrillation, 0.1%), confirming the overall safety of DSE. Most arrhythmias (88%) occurred in patients with normal potassium levels, and arrhythmia rates remained low in patients with potassium abnormalities. Patients with hyperkalemia had a lower risk of developing mild (odds ratio [OR], 0.39; 95% CI, 0.22-0.71) and severe (OR, 0.13; 95% CI, 0.01-0.68) supraventricular arrhythmias as well as mild ventricular arrhythmias (OR, 0.58; 95% CI, 0.40-0.83). Even though events were rare, patients with severe hypokalemia (potassium levels ≤ 3.1 mmol/L) had an increased risk of supraventricular arrhythmia and ventricular ectopy.

CONCLUSIONS

DSE is safe even in the setting of abnormalities in blood potassium concentrations, and hence cancellation of DSE in patients with potassium abnormalities does not appear warranted. Elevated potassium levels are associated with lower rates of clinically significant supraventricular and ventricular arrhythmias. While remaining at relatively low risk, patients with very low potassium levels (≤3.1 mmol/L) at the time of DSE have a modestly increased risk of arrhythmia. Consideration could be given to correcting severe hypokalemia prior to DSE.

Impact of Stress Testing for Coronary Artery Disease Screening in Asymptomatic Patients With Diabetes Mellitus: A Community-Based Study in Olmsted County, Minnesota

OBJECTIVE

To evaluate the impact of screening stress testing for coronary artery disease in asymptomatic patients with diabetes in a community-based population.

PATIENTS AND METHODS

This observational study included 3146 patients from Olmsted County, Minnesota, with no history of coronary artery disease or cardiac symptoms in whom diabetes was newly diagnosed from January 1, 1992, through December 31, 2008. With combined all-cause mortality and myocardial infarction as the primary outcome, weighted Cox proportional hazards regression was performed with screening stress testing within 2 years of diabetes diagnosis as the time-dependent covariate. For descriptive analysis, participants were classified by their clinical experience during the first 2 years postdiagnosis as screened (asymptomatic, underwent stress test), unscreened (asymptomatic, no stress test), or symptomatic (experienced symptoms or event).

RESULTS

Among the screened and unscreened participants, 54% (1358 of 2538) were men; the mean (SD) age at diabetes diagnosis was 55 years (13.8 years), and 97% (2442 of 2520) had type 2 diabetes. In event-free survival analysis, 292 patients comprised the screened cohort and 2246 patients comprised the unscreened cohort. Death or myocardial infarction occurred in 454 patients (32 patients in the screened cohort and 422 in the unscreened cohort [5-year rate, 1.9% and 5.3%, respectively]) during median (interquartile range) follow-up of 9.1 years (5.3-12.5 years). Screening stress testing was associated with improved event-free survival (hazard ratio, 0.61; P=.004), independent of cardiac risk factors. However, while stress test results were abnormal in 47 of the 292 screened patients (16%), only 6 (2%) underwent coronary revascularization.

CONCLUSION

Although screening cardiac stress testing in asymptomatic patients with diabetes in this community-based population was associated with improvement in long-term event-free survival, this result does not appear to occur by coronary revascularization alone.

Usefulness of High-Density Lipoprotein Cholesterol to Predict Survival in Pulmonary Arterial Hypertension

It has been suggested that lipoprotein abnormalities may contribute to the pulmonary arteriolar dysfunction observed in pulmonary arterial hypertension (PAH). High-density lipoprotein cholesterol (HDL) has vasodilatory, anti-inflammatory, and endothelial protective properties. We hypothesized that a higher serum HDL level may be advantageous for survival in PAH and that the serum HDL level at diagnosis would be an independent predictor of survival in PAH and be additive to previously validated predictors of survival. This study included all patients with PAH seen at the Mayo Clinic Pulmonary Hypertension Clinic from January 1, 1995, to December 31, 2009, who had a baseline HDL measurement. Mortality was analyzed over 5 years using the Kaplan-Meier method. Univariate and multivariable Cox proportional hazards ratios were calculated to evaluate the relation between baseline HDL level and survival. HDL levels were available for 227 patients. Higher HDL levels were associated with significantly lower mortality. Patients with an HDL >54 mg/dl at diagnosis had a 5-year survival of 59%. By comparison those with an HDL <34 mg/dl had a 5-year survival of 30%. On multivariate analysis, higher HDL was associated with an age-adjusted risk ratio for death of 0.78 (CI 0.67 to 0.91; p <0.01) per 10 mg/dl increase. In conclusion, HDL was an independent predictor of survival in PAH.

Impact of age on pulmonary artery systolic pressures at rest and with exercise

AIM

It is not well known if advancing age influences normal rest or exercise pulmonary artery pressures. The purpose of the study was to evaluate the association of increasing age with measurements of pulmonary artery systolic pressure at rest and with exercise.

SUBJECTS AND METHODS

A total of 467 adults without cardiopulmonary disease and normal exercise capacity (age range: 18-85 years) underwent symptom-limited treadmill exercise testing with Doppler measurement of rest and exercise pulmonary artery systolic pressure.

RESULTS

There was a progressive increase in rest and exercise pulmonary artery pressures with increasing age. Pulmonary artery systolic pressures at rest and with exercise were 25±5mmHg and 33±9mmHg, respectively, in those <40 years, and 30±5mmHg and 41±12mmHg, respectively, in those ≥70 years. While elevated left-sided cardiac filling pressures were excluded by protocol design, markers of arterial stiffness associated with the age-dependent effects on pulmonary pressures.

CONCLUSION

These data demonstrate that in echocardiographically normal adults, pulmonary artery systolic pressure increases with advancing age. This increase is seen at rest and with exercise. These increases in pulmonary pressure occur in association with decreasing transpulmonary flow and increases in systemic pulse pressure, suggesting that age-associated blood vessel stiffening may contribute to these differences in pulmonary artery systolic pressure.

Typical blood pressure response during dobutamine stress echocardiography of patients without known cardiovascular disease who have normal stress echocardiograms

AIMS

Blood pressure (BP) responses during dobutamine stress echocardiography (DSE) have not been systematically studied. Consequently, it is not known what constitutes a normal or an abnormal BP response to dobutamine stress. We sought to define the typical BP response during DSE of patients not known to have cardiovascular disease.

METHODS AND RESULTS

Of 24 134 patients who underwent DSE from November 2003 to December 2012 at Mayo Clinic, Rochester, MN, 2968 were selected for inclusion in this retrospective study. Excluded were patients with a history of hypertension, diabetes, or coronary artery disease, and those taking vasoactive medications. Patients who had baseline and/or stress-induced wall motion abnormalities were also excluded. The distribution of the study population's BP responses during DSE was Gaussian; we defined cut-point values for normative BP responses at 2 SD for each decade of age and for the whole study population. During DSE, systolic BP (SBP) increased from baseline to peak stress (Δ +2.9 ± 24 mmHg, P < 0.0001) and diastolic BP (DBP) decreased (Δ -7.4 ± 14 mmHg). BP changes were age and sex dependent; men and younger patients had greater ΔSBP and lesser ΔDBP, compared with women and older patients. Patients who received atropine had higher peak BP values than patients who did not receive atropine, due to greater ΔSBP (+7.4 ± 26 vs. -0.5 ± 22 mmHg, P < 0.0001) and lesser ΔDBP (-4 ± 14 vs. -9.7 ± 12 mmHg, P < 0.0001). This atropine effect was present in men and women, and was more pronounced in younger patients. The normative peak SBP values ranged from 82 to 182 mmHg.

CONCLUSION

BP responses during DSE vary and depend on patients' age, gender, and the use of atropine. We describe the typical BP responses seen during DSE and report normative reference values, which can be used for defining normal and abnormal BP responses to dobutamine stress.

Severe reversible pulmonary hypertension in smoldering multiple myeloma: two cases and review of the literature

An association between pulmonary hypertension (PH) and POEMS syndrome (characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) as well as other plasma cell dyscrasias, including multiple myeloma (MM), has been shown to exist. Recent case reports have identified a reversible form of PH that occurs outside of previously identified etiologies. We report two cases of PH in the setting of smoldering MM (SMM) that resolved with chemotherapy and stem cell transplantation. Although other features were individualized among the cases (dermatomyositis, scleromyxedema), treatment of MM and SMM resulted in a normalization of right ventricular systolic pressure and improvement in right ventricular dysfunction that was previously unresponsive to PH therapies. The magnitude and sustained nature of reversibility in these four cases could offer clues about the pathophysiology and treatment of PH.

Echocardiographic determinants of peak aerobic capacity and breathing efficiency in patients with undifferentiated dyspnea

Diastolic function and E/e' correlate with peak aerobic capacity (VO2) in patients with heart failure, but the echocardiographic correlates of abnormal gas exchange in patients without heart failure are not well defined. We sought to determine the echocardiographic correlates of peak VO2 and breathing efficiency (estimated using the ratio of minute ventilation to carbon dioxide production, or VE/VCO2 nadir) in patients with unexplained dyspnea. We identified 232 patients with unexplained dyspnea who underwent echocardiography at rest followed by stress echocardiography with simultaneous measurement of peak VO2 and VE/VCO2 nadir. At baseline, 17 patients (5%) had an E/e' of ≥15 while 31 patients (17%) had a right ventricular systolic pressure (RVSP) of >35 mm Hg. E/e' ≥15 and RVSP >35 mm Hg were associated with lower peak VO2 (14.1 ± 4.4 vs 21.0 ± 6.9 and 15.2 ± 3.6 vs 21.8 ± 6.8 ml/kg/min, respectively, p <0.0001). E/e' ≥15 (sensitivity 0.13, specificity 0.99, area under the curve 0.64) and RVSP >35 mm Hg (sensitivity 0.38, specificity 0.93, area under the curve 0.76) were highly specific for predicting limited peak VO2. Age and RVSP at rest were independent correlates with VE/VCO2, but diastolic function was not. However, the risk of having abnormal VE/VCO2 nadir was only elevated in subjects with elevated RVSP in the setting of abnormal diastolic function (hazard ratio 2.4, 95% confidence interval 1.3 to 4.6, p = 0.02). In conclusion, both E/e' ≥15 and RVSP >35 mm Hg are highly specific markers of exercise limitation in patients without heart failure, but RVSP at rest may offer better overall diagnostic power than E/e' to predict low peak VO2 in this group.

Pericardial effusions in pulmonary arterial hypertension: characteristics, prognosis, and role of drainage

BACKGROUND

The presence and size of a pericardial effusion in pulmonary arterial hypertension (PAH) and its association with outcome is unclear.

METHODS

In this single-center cohort study of 577 patients with group 1 PAH seen between January 1, 1995, and December 31, 2005, all patients underwent transthoracic echocardiography and were followed for ≥ 5 years. Echocardiography-guided pericardiocentesis was performed as needed.

RESULTS

Pericardial effusions on index echocardiography occurred in 150 patients (26%); 128 patients had small and 22 had moderate-sized or larger effusions. Most of the moderate or greater effusions occurred in patients who had connective tissue disease (82%). Mean right atrial pressure was 13.4 ± 4.4 mm Hg (no effusion), 15.1 ± 4.4 mm Hg (small effusion), and 17.0 ± 4.0 mm Hg (moderate or greater effusion) (P &lt; .0001). Median survival for patients with moderate or greater effusion, mild effusion, or no effusion was 11.3 months, 42.3 months, and 76.5 months, respectively. Four of the 22 patients with moderate or greater pericardial effusions eventually required echocardiography-guided pericardiocentesis because of clinical and echocardiographic evidence of hemodynamic impact. When drained, the effusions were large (858 ± 469 mL) and generally serous. All pericardiocenteses were performed cautiously under echocardiographic guidance by a highly experienced echocardiologist, with low immediate morbidity and mortality.

CONCLUSIONS

Pericardial effusions are relatively common but rarely of hemodynamic significance in patients with PAH. However, even modest degrees of pericardial fluid are associated with a significant increase in mortality and appear to reflect the presence of associated collagen vascular disease and high right atrial pressure.

Characteristics and outcomes of patients who achieve high workload (≥10 metabolic equivalents) during treadmill exercise echocardiography

OBJECTIVE

To determine the frequency and prognostic significance of abnormal exercise echocardiographic results for patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise echocardiography.

PATIENTS AND METHODS

Patients who underwent treadmill exercise echocardiography from November 1, 2003, through December 31, 2008, and exercised for 9 or more minutes using the Bruce protocol (N=7236) were included. Clinical and exercise echocardiographic characteristics and outcomes were evaluated. Variables associated with abnormal exercise echocardiographic results and mortality were identified.

RESULTS

Exercise echocardiographic results were positive for ischemia in 862 patients (12%). Extensive ischemia developed in 265 patients (4%). For patients with normal exercise echocardiographic results, all-cause and cardiovascular mortality rates were 0.30% and 0.05% per person-year of follow-up, respectively. For patients who had extensive ischemia, all-cause and cardiovascular mortality rates were 0.84% and 0.25% per person-year of follow-up, respectively. Patients at highest risk were those who had extensive and severe regional wall motion abnormalities at rest (n=58), and their all-cause and cardiovascular mortality rates were 2.65% and 0.76% per person-year of follow-up. Exercise echocardiographic variables did not identify sizable patient subgroups at risk for death and did not provide incremental prognostic information (C statistic was 0.74 compared with 0.73 for the clinical plus exercise electrocardiography model).

CONCLUSION

Patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise testing do not often have extensive ischemic abnormalities on exercise echocardiography. Although exercise echocardiographic results provide some prognostic information, it is not of incremental value for these patients, whose short-term and medium-term prognosis is excellent.

Left ventricular diastolic function and long-term outcomes in patients with normal exercise echocardiographic findings

The objective of the present study was to determine whether diastolic dysfunction (DD) is associated with outcomes in the absence of myocardial ischemia. We studied 2,835 patients undergoing exercise echocardiography from January 2006 through December 2006 who had normal systolic function (ejection fraction ≥50%) and an absence of exercise-induced wall motion abnormalities. Diastolic function was graded as normal, mild DD, or moderate to severe DD. Medical records review and patient contact were undertaken to determine mortality, cardiovascular events (i.e., death, myocardial infarction, or stroke), incident heart failure (HF), and hospitalization. The mean ± SD age was 58.9 ± 12.8 years, and 54.0% were women. DD was present in 40.0% of the participants, with mild DD in 28.2% and moderate to severe DD in 11.8%. During a median follow-up of 4.4 years, 81 deaths and 114 cardiovascular events occurred, and DD was associated with greater rates of mortality, cardiovascular events, and HF events or hospitalizations (all p <0.001). On multivariate analysis, mild or moderate to severe DD (referent, normal function) was associated with HF or hospitalization (hazard ratio 1.45, 95% confidence interval 1.18 to 1.78, p <0.001 for mild DD; hazard ratio 1.75, 95% confidence interval 1.37 to 2.24, p <0.001 for moderate to severe DD) but was not independently associated with death or cardiovascular events. The diastolic index of filling pressure (E/e') was independently associated with mortality, cardiovascular events, and HF or hospitalization. In conclusion, among patients without demonstrable myocardial ischemia, left ventricular DD was associated with greater event rates during long-term follow up but did not independently predict hard end points other than HF or hospitalization. E/e' was independently associated with the clinical outcomes and might be an important echocardiographically derived parameter to identify in patients undergoing exercise echocardiography.

Population-based study of the use of cardiac stress imaging and referral for coronary angiography and repeated revascularization after coronary artery bypass graft surgery

OBJECTIVE

To assess stress single-photon emission computed tomography (SPECT) and stress echocardiography use after coronary artery bypass grafting (CABG) and their effect on referral for coronary angiography and revascularization.

PATIENTS AND METHODS

The referral, timing, and results of stress imaging after CABG; referral for coronary angiography and revascularization; and all-cause mortality were assessed in this longitudinal, population-based, retrospective study of 1138 Olmsted County, Minnesota, patients undergoing CABG between January 1, 1993, and December 31, 2003.

RESULTS

A total of 570 patients (50.1%) underwent a stress imaging study (341 SPECT and 229 echocardiography) during the study period. Of the 1138 patients, 372 (32.7%) were referred for coronary angiography, and 144 of those patients (12.7%) underwent repeated revascularization (132 percutaneous revascularization and 12 CABG). The median interval between CABG and the index stress imaging study was 3.0 years (25th-75th percentile, 1.2-5.7 years). The results of 75.7% (258 of 341) of the stress SPECT studies and 70.7% (162 of 229) of the stress echocardiograms were abnormal. Seventy-six of 570 patients (13.3%) referred for stress imaging underwent coronary angiography within 180 days after the stress test. Repeated coronary revascularization was performed in 25 patients (4.4%) who underwent a stress imaging study within the preceding 180 days. The 5- and 10-year survival rates in the entire study cohort (83.5% and 65.1%, respectively) were not significantly different than predicted for the age- and sex-matched Minnesota population.

CONCLUSION

Half of this community-based population of patients with CABG underwent stress SPECT or echocardiography during median follow-up of 8.9 years. Despite that approximately 75% of the results of stress imaging studies were abnormal, subsequent referral for coronary angiography within 180 days was low (13.3%), and the yield for repeated revascularization was very low (4.4%).

Characteristics and outcomes of patients with abnormal stress echocardiograms and angiographically mild coronary artery disease (<50% stenoses) or normal coronary arteries

BACKGROUND

Abnormal cardiac stress imaging findings are not always associated with angiographically significant coronary artery disease. The outcomes of patients with such false-positive findings have not been extensively examined. The aim of this retrospective study was to describe the characteristics and outcomes of patients with abnormal stress echocardiographic findings who had false-positive results compared with those who had true-positive results.

METHODS

Of 1,477 consecutive patients (mean age, 66 +/- 12 years; 61% men) with abnormal stress echocardiographic findings who underwent coronary arteriography within 30 days, death from any cause was ascertained.

RESULTS

At coronary arteriography, 997 patients (67.5%) had true-positive results, defined by the presence of angiographically significant coronary artery disease (> or = 50% stenoses), and 480 (32.5%) had false-positive results, defined by <50% stenoses or normal coronary arteries. Of the subgroup of patients with markedly abnormal stress echocardiographic findings (n = 605), 28% had <50% stenoses or normal coronary arteries. During an average follow-up period of 2.4 +/- 1.0 years, there were 140 deaths. The adjusted likelihood of subsequent death for patients with <50% stenoses compared to patients with > or = 50% stenoses after abnormal stress echocardiography was 1.05 (95% confidence interval, 0.86-1.31; P = .62).

CONCLUSIONS

A sizable proportion of patients with abnormal stress echocardiographic results who are referred for coronary angiography have false-positive findings. The outcomes of patients with false-positive results were similar to those of patients with true-positive results. This finding suggests that patients with false-positive results on stress echocardiography should still receive intensive risk factor management and careful clinical follow-up.

Evaluation of coronary CTA Appropriateness Criteria in an academic medical center

BACKGROUND

The aim of this study was to evaluate published appropriateness criteria for CT angiography (CTA) at the authors' academic medical center.

METHODS

Two observers independently reviewed the medical records of 251 patients who had undergone dual-source coronary CTA from June 1 to December 31, 2007. Patients were assigned to indications from 1 of 7 tables from the American College of Cardiology Foundation and ACR Appropriateness Criteria. Agreement between the two observers was assessed using kappa statistics. Disagreements were resolved by consensus panel. The final numbers of appropriate, uncertain, inappropriate, and not classifiable indications were recorded.

RESULTS

Indications for testing were classified as appropriate in 69 patients (27%), inappropriate in 42 patients (17%), and uncertain in 25 patients (10%). One hundred fifteen indications for coronary CTA (46%) were not classifiable. Analysis of interobserver variability for overall appropriateness yielded a kappa value of 0.31, which was considered to indicate fair agreement.

CONCLUSION

The results of this study suggest that a significant proportion (46%) of the coronary CTA studies performed at the authors' institution are for indications that are not covered by the published appropriateness criteria. Modifications to these criteria could help decrease the number of studies that are not classifiable. Physician education could decrease the number of inappropriate studies.

Size, shape, and stamina: the impact of left ventricular geometry on exercise capacity

Although several studies have examined the cardiac functional determinants of exercise capacity, few have investigated the effects of structural remodeling. The current study evaluated the association between cardiac geometry and exercise capacity. Subjects with ejection fraction > or = 50% and no valvular disease, myocardial ischemia, or arrhythmias were identified from a large prospective exercise echocardiography database. Left ventricular mass index and relative wall thickness were used to classify geometry into normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. All of the subjects underwent symptom-limited treadmill exercise according to standard Bruce protocol. Maximal exercise tolerance was measured in metabolic equivalents. Of 366 (60+/-14 years; 57% male) subjects, 166 (45%) had normal geometry, 106 (29%) had concentric remodeling, 40 (11%) had eccentric hypertrophy, and 54 (15%) had concentric hypertrophy. Geometry was related to exercise capacity: in descending order, the maximum achieved metabolic equivalents were 9.9+/-2.8 in normal, 8.9+/-2.6 in concentric remodeling, 8.6+/-3.1 in eccentric hypertrophy, and 8.0+/-2.7 in concentric hypertrophy (all P<0.02 versus normal). Left ventricular mass index and relative wall thickness were negatively correlated with exercise tolerance in metabolic equivalents (r=-0.14; P=0.009 and r=-0.21; P<0.001, respectively). Augmentation of heart rate and ejection fraction with exercise were blunted in concentric hypertrophy compared with normal, even after adjusting for medications. In conclusion, the pattern of ventricular remodeling is related to exercise capacity among low-risk adults. Subjects with concentric hypertrophy display the greatest limitation, and this is related to reduced systolic and chronotropic reserve. Reverse remodeling strategies may prevent or treat functional decline in patients with structural heart disease.

Pretest score for predicting microbubble contrast agent use in stress echocardiography: a method to increase efficiency in the echo laboratory

Background. In stress echocardiography, contrast agents are used selectively to improve endocardial border definition. Early identification of candidates may facilitate use of these agents in small and medium volume laboratories where resources are limited. Methods. We studied 15232 patients who underwent stress echocardiography. Contrast agent was used if 2 or more ventricular segments were not adequately visualized without contrast. Logistic regression models were used to evaluate the association between individual characteristics and contrast use. An 11-point score was derived from the significant characteristics. Results. Variables associated with microbubble use were age, sex, smoking, presence of multiple risk factors, bodymass index (BMI), referral for dobutamine stress echocardiography, history of coronary artery disease, and abnormal baseline electrocardiogram. All variables except BMI were given a score of 1 if present and 0 if absent; BMI was given a score of 0 to 4 according to its value. An increased score was directly proportional to increased likelihood of contrast use. The score cutoff value to optimize sensitivity and specificity was 5. Conclusions. A pretest score can be computed from information available before imaging. It may facilitate contrast agent use through early identification of patients who are likely to benefit from improved endocardial border definition.

Are some false-positive stress echocardiograms a forme fruste variety of apical ballooning syndrome?

The mechanisms for abnormal stress echocardiograms (SEs) in patients with normal coronary arteries have not been clearly elucidated. We hypothesized that in some patients, this phenomenon may represent a forme fruste of apical ballooning syndrome (ABS). The aim of the study was to evaluate the characteristics of patients with strongly false-positive SEs and determine whether there were similarities to ABS. Thirty-one patients from the Mayo Clinic stress echocardiography database who had normal function at rest, extensive regional wall motion abnormalities in association with an abnormal response of left ventricular end-systolic cavity size at peak stress, and angiographically normal coronary arteries were evaluated. Eighty-four percent were women with a mean age of 61 +/- 12 years, 6% had a positive stress electrocardiogram, and only 26% had a hypertensive response to stress. In 81%, left ventricular ejection fraction decreased with stress and 97% developed new regional wall motion abnormalities in > or =4 segments. Peak wall motion score index was 1.65 +/- 0.39. Midventricular (100%) and apical (87%) segments were most often involved with relative sparing of the basal segments (77%; p = 0.01). There were no deaths during follow-up (2.3 +/- 0.7 years). In conclusion, the major findings of this study were that strongly false-positive SEs occurred predominantly in postmenopausal women, and frequently involved the apical and mid-left ventricular segments, features that were similar to ABS. Data were consistent with the hypothesis that some false-positive SEs may represent a forme fruste of ABS.

Applicability of Appropriateness Criteria for Stress Imaging

Background— Appropriateness criteria for stress imaging have been published to promote the effective use of stress nuclear scintigraphy and stress echocardiography. We sought to evaluate the application of the stress echocardiography appropriateness criteria to patients undergoing stress echocardiography in an academic medical center.

Methods and Results— The stress echocardiography criteria were applied to 298 consecutive patients who underwent stress echocardiography. Patients were rated as appropriate, uncertain, inappropriate, or not classifiable. Results were compared with those of a previous analysis in the same patients using the single-photon computed tomography myocardial perfusion imaging (SPECT MPI) criteria. The level of agreement between 2 cardiac nurse abstractors for categorizing appropriateness by the stress echocardiography criteria was good (κ=0.72). Overall, 54% of patients were classified as appropriate, 8% as uncertain, and 19% as inappropriate; 19% were not classifiable. By the SPECT MPI criteria, 64% of patients were classified as appropriate, 9% as uncertain, and 18% as inappropriate; 9% were not classifiable ( P <0.001 compared with stress echocardiography criteria). By the stress echocardiography criteria, 6 clinical situations or indications accounted for more than 90% of the inappropriate tests; most of these involved asymptomatic patients.

Conclusions— Applying stress echocardiography appropriateness criteria to a patient population is feasible, although 1 in 5 of our patients was not classifiable. Overall, the stress echocardiography criteria classified patients differently compared with the SPECT MPI criteria. Future refinements of the appropriateness criteria for stress imaging should address gaps in the criteria and disparities between the stress echocardiography and SPECT MPI criteria.

Left ventricular function and exercise capacity

CONTEXT

Limited information exists regarding the role of left ventricular function in predicting exercise capacity and impact on age- and sex-related differences.

OBJECTIVES

To determine the impact of measures of cardiac function assessed by echocardiography on exercise capacity and to determine if these associations are modified by sex or advancing age.

DESIGN

Cross-sectional study of patients undergoing exercise echocardiography with routine measurements of left ventricular systolic and diastolic function by 2-dimensional and Doppler techniques. Analyses were conducted to determine the strongest correlates of exercise capacity and the age and sex interactions of these variables with exercise capacity.

SETTING

Large tertiary referral center in Rochester, Minnesota, in 2006.

PARTICIPANTS

Patients undergoing exercise echocardiography using the Bruce protocol (N = 2867). Patients with echocardiographic evidence of exercise-induced ischemia, ejection fractions lower than 50%, or significant valvular heart disease were excluded.

MAIN OUTCOME MEASURE

Exercise capacity in metabolic equivalents (METs).

RESULTS

Diastolic dysfunction was strongly and inversely associated with exercise capacity. Compared with normal function, after multivariate adjustment, those with moderate/severe resting diastolic dysfunction (-1.30 METs; 95% confidence interval [CI], -1.52 to -0.99; P < .001) and mild resting diastolic dysfunction (-0.70 METs; 95% CI, -0.88 to -0.46; P < .001) had substantially lower exercise capacity. Variation of left ventricular systolic function within the normal range was not associated with exercise capacity. Left ventricular filling pressures measured by resting E/e' of 15 or greater (-0.41 METs; 95% CI, -0.70 to -0.11; P = .007) or postexercise E/e' of 15 or greater (-0.41 METs; 95% CI, -0.71 to -0.11; P = .007) were similarly associated with a reduction in exercise capacity, each in separate multivariate analyses. Individuals with impaired relaxation (mild dysfunction) or resting E/e' of 15 or greater had a progressive increase in the magnitude of reduction in exercise capacity with advancing age (P < .001 and P = .02, respectively). Other independent correlates of exercise capacity were age (unstandardized beta coefficient, -0.85 METs; 95% CI, -0.92 to -0.77, per 10-year increment; P < .001), female sex (-1.98 METs; 95% CI, -2.15 to -1.84; P < .001), and body mass index greater than 30 (-1.24 METs; 95% CI, -1.41 to -1.10; P < .001).

CONCLUSION

In this large cross-sectional study of those referred for exercise echocardiography and not limited by ischemia, abnormalities of left ventricular diastolic function were independently associated with exercise capacity.

Safety of Stress Echocardiography Supervised by Registered Nurses: Results of a 2-Year Audit of 15,404 Patients

BACKGROUND

Stress echocardiography has traditionally been performed under the supervision of physicians. In the last decade, at some institutions, specially trained registered nurses have taken on the task of directly supervising and conducting these stress tests with appropriate physician involvement and assistance.

METHODS

The safety of 15,404 stress echocardiograms that were performed under the direct supervision of registered nurses during a recent 2-year period was evaluated.

RESULTS

The stress modality was treadmill exercise in 8592 (56%), dobutamine in 6755 (44%), and transesophageal atrial pacing in 57 (0.04%) patients. The mean age was 65 +/- 13 years, and 54% were male. A total of 55 patients (0.36%) had complications related to stress echocardiography, including 26 patients (0.18%) who were subsequently transferred to hospital. Complications included atrial fibrillation (n = 28, 0.18%), other supraventricular tachycardias (n = 9, 0.06%), sustained ventricular tachycardia (n = 4, 0.03%), and ventricular fibrillation (n = 2, 0.01%). Eight patients (0.05%) were hospitalized for markedly positive tests or prolonged chest pain and 4 patients (0.03%) for symptomatic hypotension. No patient had cardiac rupture or died. Complications were more common with dobutamine stress echocardiography (DSE) (47/6755; 0.7%) compared with exercise echocardiography (8/8592; 0.09%) or transesophageal atrial pacing stress echocardiography (0/57) (P < .0001). Arrhythmias were more commonly associated with DSE (39/6755, 0.58%) than exercise echocardiography (4/8592, 0.05%). Potentially life-threatening ventricular arrhythmias occurred in 6 of 6755 patients who underwent DSE (0.09%) and in none of the patients who underwent exercise echocardiography. Patients who underwent DSE were, on average, older, and had more comorbidities compared with those who underwent exercise echocardiography.

CONCLUSIONS

Stress echocardiography, when supervised directly by specially trained registered nurses, can be performed safely; complications are uncommon (1/280 stress tests) and these complication rates are comparable with previously reported studies evaluating the safety of stress echocardiography supervised by physicians.

Relationship between coronary artery calcification detected by electron-beam computed tomography and abnormal stress echocardiography: association and prognostic implications

OBJECTIVES

The purpose of this study was to compare the results and prognostic value of electron-beam computed tomography (EBCT) and exercise echocardiography.

BACKGROUND

Although patients with elevated coronary artery calcium scores (CACS) might be referred for exercise echocardiography, the association of EBCT CACS with wall motion score index (WMSI) is not known.

METHODS

Patients without known coronary artery disease who underwent both clinically indicated EBCT and exercise echocardiography within a 3-month period were identified. Exercise WMSI was based on a 16-segment model (normal = 1; abnormal >1). The EBCT CACS was derived with the Agatston scoring system. Follow-up was obtained for the combined end point of death and myocardial infarction.

RESULTS

The study population included 556 patients (age 54 +/- 10 years; 65% male). Correlation between EBCT CACS and exercise WMSI was limited (r = 0.17, p < 0.0001) but statistically significant. The proportion of patients with abnormal exercise WMSI increased with increasing CACS severity (chi-square = 19.1, p < 0.001). However, even in those with CACS >400, 66% had normal exercise WMSI. Age, CACS, and chest pain were independently associated with abnormal exercise WMSI. Events occurred in 12 (2%) patients. Wall motion score index (risk ratio [RR] 3.7, p = 0.023) and age (RR 1.9, p = 0.019) were associated with events.

CONCLUSIONS

Electron-beam computed tomography CACS was predictive of abnormal exercise WMSI, but the majority of patients with elevated CACS had normal WMSI. Wall motion score index and age were the best predictors of events. Prospective studies are indicated to establish the relative roles of these tests in risk stratification.