Dobutamine stress PET/CT for assessment of hemodynamic significance of coronary myocardial bridges.

Myocardial bridges are common and often benign, but can cause hemodynamically significant obstruction of blood flow with stress. Dobutamine stress positron emission tomography/computed tomography (PET/CT) is a powerful tool for non-invasively assessing for ischemia. We present a case of using dobutamine stress PET/CT to determine the significance of a myocardial bridge.

Multimodality Imaging Assessment of Fabry Disease.

Fabry disease is a lysosomal storage disease with a variety of cardiac manifestations. Although not specific for a diagnosis of Fabry disease, certain cardiac imaging findings may be highly suggestive of the diagnosis of Fabry disease in previously undiagnosed patients or cardiac involvement for patients with a known diagnosis of Fabry disease. In this review, we explore the current applications of multimodality cardiac imaging in the diagnosis and monitoring of patients with Fabry disease. Additionally, data regarding tissue characterization by cardiac magnetic resonance imaging and novel nuclear imaging techniques and their role in evaluating phenotype development is discussed.

Comprehensive Echocardiographic Assessment of Normal Transcatheter Valve Function.

OBJECTIVES: This study aims to establish parameters for identifying normal function for each of the 3 iterations of balloon-expandable valves and 2 iterations of self-expanding valves. BACKGROUND: Expected transthoracic echocardiographic Doppler-derived hemodynamic data for transcatheter aortic valves inform pre-implant decision-making and post-implanted monitoring of longitudinal valve function. METHODS: We collected the echocardiography core Lab measured mean gradients and effective orifice area (EOA) from discharge or 30-day echocardiograms from randomized trials; the PARTNER (Placement of Aortic Transcatheter Valves) trials for the balloon-expandable valves and the Medtronic CoreValve US Pivotal trial and Medtronic CoreValve Evolut R United States IDE Clinical Study for the self-expanding valves. RESULTS: For all SAPIEN (Edwards Lifesciences, Irvine, California) valve sizes, mean EOA is 1.70 ± 0.49 cm2 with a mean gradient of 9.36 ± 4.13 mm Hg. For all SAPIEN XT valve sizes, mean EOA is 1.67 ± 0.46 cm2 with a mean gradient of 9.52 ± 3.64 mm Hg. For all SAPIEN 3 valve sizes, the mean EOA is 1.66 ± 0.38 cm2 with a mean gradient of 11.18 ± 4.35 mm Hg. For all CoreValve valve sizes, the mean EOA is 1.88 ± 0.56 cm2 with a mean gradient of 8.85 ± 4.14 mm Hg. For all Evolut R valve sizes, the mean EOA is 2.01 ± 0.65 cm2 with a mean gradient of 7.52 ± 3.19 mm Hg. The SAPIEN 3 post-implant EOA was progressively larger for each quintile of baseline annular area by computed tomography (p < 0.001). Similarly, for the Evolut R valve, post-implantation EOA was significantly larger for each quintile of baseline annular perimeter (p < 0.001). CONCLUSIONS: Tables of expected mean transcatheter aortic valve hemodynamics by valve type and size are essential in evaluating the function of these transcatheter prosthetic valves. Tables of expected EOA by the native annular anatomy may be useful for pre-implantation decision making. Criteria for defining structural valve dysfunction are proposed.

Artificial neural network-based model enhances risk stratification and reduces non-invasive cardiac stress imaging compared to Diamond-Forrester and Morise risk assessment models: A prospective study.

BACKGROUND: Coronary artery disease (CAD) accounts for more than half of all cardiovascular events. Stress testing remains the cornerstone for non-invasive assessment of patients with possible or known CAD. Clinical utilization reviews show that most patients presenting for evaluation of stable CAD by stress testing are categorized as low risk prior to the test. Attempts to enhance risk stratification of individuals who are sent for stress testing seem to be more in need today. The present study compares artificial neural networks (ANN)-based prediction models to the other risk models being used in practice (the Diamond-Forrester and the Morise models). METHODS: In our study, we prospectively recruited patients who were 19 years of age or older, and were being evaluated for coronary artery disease with imaging-based stress tests. For ANN, the network architecture employed a systematic method, where the number of neurons is changed incrementally, and bootstrapping was performed to evaluate the accuracy of the models. RESULTS: We prospectively enrolled 486 patients. The mean age of patients undergoing stress test was 55.2 ± 11.2 years, 35% were women, and 12% had a positive stress test for ischemic heart disease. When compared to Diamond-Forrester and Morise risk models, the ANN model for predicting ischemia provided higher discriminatory power (DP)(1.61), had a negative predictive value of 98%, Sensitivity 91% [81%-97%], Specificity 65% [60%-79%], positive predictive value 26%, and a potential 59% reduction of non-invasive imaging. CONCLUSION: The ANN models improved risk stratification when compared to the other risk scores (Diamond-Forrester and Morise) with a 98% negative predictive value and a significant potential reduction in non-invasive imaging tests.

Gender Disparities in Outcomes and Resource Utilization for Acute Pulmonary Embolism Hospitalizations in the United States.

Current data regarding gender disparities in outcomes after acute pulmonary embolism (PE) are limited and controversial. We sought to assess the gender-specific rates and trends in treatment, outcomes, and complications after acute PE. We used the 2003 to 2011 Nationwide Inpatient Sample database for this analysis. All hospital admissions with a principal diagnosis of acute PE were identified using the International Classification of Diseases, Ninth Edition, codes. Inhospital mortality and discharge to nursing facility were co-primary outcomes of our study. Secondary outcomes included shock, transfusion of blood products, utilization of thrombolysis, inferior vena cava filter placement, and cost of hospitalization. Over a 9-year period, a total of 276,484 discharges with acute PE were identified. Compared with men, there was significantly higher inhospital mortality in women admitted with acute PE (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.03 to 1.15). In addition, there was a significantly higher need for discharge to nursing facility among women compared with men (OR 1.30, 95% CI 1.27 to 1.34). Besides this, women experienced a higher need for transfusion (OR 1.38, 95% CI 1.33 to 1.44) and occurrence of shock (OR 1.10, 95% CI 1.01 to 1.18) during hospitalization. Furthermore, there was a significantly lower utilization of vena cava filters (OR 0.86, 95% CI 0.84 to 0.89) in women compared with men. Among patients in shock who were eligible for thrombolysis (age <75 years, no previous stroke, no bleeding on presentation, and not pregnant), the utilization of thrombolysis was similar between men and women (OR 1.19, 95% CI 0.93 to 1.53). Lastly, the cost of hospitalization after acute PE was significantly higher in men than women (adjusted mean difference $425, 95% CI $304 to $546). In conclusion, among patients admitted with acute PE, women tend to have more adverse outcomes and higher incidence of complications compared with men.

Outcomes after acute ischemic stroke in the United States: does residential ZIP code matter?

BACKGROUND: We sought to analyze the impact of socioeconomic status (SES) on in-hospital outcomes, cost of hospitalization, and resource use after acute ischemic stroke. METHODS AND RESULTS: We used the 2003-2011 Nationwide Inpatient Sample database for this analysis. All admissions with a principal diagnosis of acute ischemic stroke were identified by using International Classification of Diseases, Ninth Revision codes. SES was assessed by using median household income of the residential ZIP code for each patient. Quartile 1 and quartile 4 reflect the lowest-income and highest-income SES quartile, respectively. During a 9-year period, 775,905 discharges with acute ischemic stroke were analyzed. There was a progressive increase in the incidence of reperfusion on the first admission day across the SES quartiles (P-trend<0.001). In addition, we observed a significant reduction in discharge to nursing facility, across the SES quartiles (P-trend<0.001). Although we did not observe a significant difference in in-hospital mortality across the SES quartiles in the overall cohort (P-trend=0.22), there was a significant trend toward reduced in-hospital mortality across the SES quartiles in younger patients (<75 years) (P-trend<0.001). The mean length of stay in the lowest-income quartile was 5.75 days, which was significantly higher compared with other SES quartiles. Furthermore, the mean adjusted cost of hospitalization among quartiles 2, 3, and 4, compared with quartile 1, was significantly higher by $621, $1238, and $2577, respectively. Compared with the lowest-income quartile, there was a significantly higher use of echocardiography, invasive angiography, and operative procedures, including carotid endarterectomy, in the highest-income quartile. CONCLUSIONS: Patients from lower-income quartiles had decreased reperfusion on the first admission day, compared with patients from higher-income quartiles. The cost of hospitalization of patients from higher-income quartiles was significantly higher than that of patients from lowest-income quartiles, despite longer hospital stays in the latter group. This might be partially attributable to a lower use of key procedures among patients from lowest-income quartile.

Assessment of paravalvular aortic regurgitation after transcatheter aortic valve replacement: intra-core laboratory variability.

BACKGROUND: There is significant disparity in the reported incidence of moderate and severe paravalvular aortic regurgitation (PAR) between the Placement of Aortic Transcatheter Valves (PARTNER) I and PARTNER II trials, which may be related to the echocardiographic methodologies used by separate core laboratories. To further explore the variability in echocardiographic interpretation of PAR, agreement between the grading of PAR by the core laboratory of PARTNER IIB was compared with that by a consortium of echocardiography core laboratory directors. METHODS: The PARTNER IIB core laboratory reevaluated patients using primarily the circumferential extent of the regurgitant jet for PAR. A consortium of echocardiography core laboratory directors was formed to evaluate the echocardiographic images and to grade PAR and central and total aortic regurgitation in a randomly chosen subset of the randomized patients in the PARTNER IIB trial using a multiwindow, multiparametric approach. Both a four-class scale (none or trace, mild, moderate, and severe) and a seven-class (none, trace, mild, mild to moderate, moderate, moderate to severe, and severe) scale were used. Levels of grading agreement between the consortium and original core laboratory in both scales were determined using weighted κ statistics. RESULTS: Only 87 patients assessed for PAR by the consortium could be paired with readings by the PARTNER IIB core laboratory. Using the four-class grading scheme the weighted κ statistic for PAR was 0.481 (95% confidence limits, 0.367, 0.595). Using the seven-class scale, the weighted κ statistic for PAR was 0.517 (95% confidence limits, 0.431, 0.607). For either grading scheme, 15.9% of patients graded by the PARTNER IIB core laboratory as having moderate PAR would have been graded as having mild PAR using the multiparametric approach. Similar results were seen for central and total aortic regurgitation assessments. CONCLUSIONS: Using primarily the circumferential extent criteria, the PARTNER IIB core laboratory overestimated the severity of PAR compared to the consortium using a multi-parametric approach. Although a more granular classification scheme for PAR may slightly improve concordance between core laboratories, differences in the incidence of moderate or severe PAR are likely related to differences in grading methodology. A multiparametric approach is advocated, and other echocardiographic methods for assessing PAR deserve further study.

Outcomes and resource utilization in ST-elevation myocardial infarction in the United States: evidence for socioeconomic disparities.

BACKGROUND: Socioeconomic status (SES) as reflected by residential zip code status may detrimentally influence a number of prehospital clinical, access-related, and transport variables that influence outcome for patients with ST-elevation myocardial infarction (STEMI) undergoing reperfusion. We sought to analyze the impact of SES on in-hospital mortality, timely reperfusion, and cost of hospitalization following STEMI. METHODS AND RESULTS: We used the 2003-2011 Nationwide Inpatient Sample database for this analysis. All hospital admissions with a principal diagnosis of STEMI were identified using ICD-9 codes. SES was assessed using median household income of the residential zip code for each patient. There was a significantly higher mortality among the lowest SES quartile as compared to the highest quartile (OR [95% CI]: 1.11 [1.06 to 1.17]). Similarly, there was a highly significant trend indicating a progressively reduced timely reperfusion among patients from lower quartiles (OR [95% CI]: 0.80 [0.74 to 0.88]). In addition, there was a lower utilization of circulatory support devices among patients from lower as compared to higher zip code quartiles (OR [95% CI]: 0.85 [0.75 to 0.97]). Furthermore, the mean adjusted cost of hospitalization among quartiles 2, 3, and 4, as compared to quartile 1 was significantly higher by $913, $2140, and $4070, respectively. CONCLUSIONS: Patients residing in zip codes with lower SES had increased in-hospital mortality and decreased timely reperfusion following STEMI as compared to patients residing in higher SES zip codes. The cost of hospitalization of patients from higher SES quartiles was significantly higher than those from lower quartiles.

Prognostic value of left ventricular mechanical dyssynchrony by phase analysis in patients with non-ischemic cardiomyopathy with ejection fraction 35-50% and QRS < 150 ms.

BACKGROUND: Left ventricular mechanical dyssynchrony (LVMD) by phase analysis of gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a useful tool for predicting response to cardiac resynchronization therapy and has prognostic value. While most of the studies were done on patients with ischemic cardiomyopathy or those with LV ejection fraction (EF) < 35%, there are little data on the prognostic value of LVMD in patients with non-ischemic cardiomyopathy (NICM), particularly those with mildly decreased systolic function and narrow or intermediate QRS duration. METHODS AND RESULTS: From the stress SPECT-MPI database at Cleveland Clinic, we identified 324 consecutive patients (mean age 62 ± 13 years, 62% male, 36% diabetics) with NICM, LVEF 35-50% (median [Q1,Q3] 45 [41,49]), and QRS < 150 ms (13% with QRS 120-149 ms). LVMD was determined from gated stress images and expressed as phase standard deviation (SD) and histogram BW (% R-R cycle). For easier graphical illustration, patients were divided into tertiles of LVMD. All-cause death was the primary endpoint and determined using the Social Security Death Index. Cox proportional hazard model was performed to determine the independent predictive value of LVMD, and next Cox models for incremental value. After a mean follow-up time of 1,689 days, 86 (26.5%) of patients died. These patients were older, had more diabetes, more use of diuretics, with wider QRS duration, and with a trend for higher phase SD and BW. After adjusting for age, hypertension, diabetes, aspirin, beta-blockers, diuretics, QRS, and EF, phase SD was an independent predictor of all-cause mortality with hazard ratio [95% CI] 1.97 [1.06,3.66] for the highest tertile, and added incremental prognostic value (P = .025). Similar findings were obtained using histogram BW. CONCLUSION: In patients with NICM, EF 35-50%, and QRS < 150 ms, increased LVMD on peak stress SPECT was an independent predictor of all-cause mortality. The utility and applicability of such findings in clinical practice need further evaluation in larger and prospective studies.

Appropriate test selection for single-photon emission computed tomography imaging: association with clinical risk, posttest management, and outcomes.

BACKGROUND: Appropriate use criteria (AUC) for stress single-photon emission computed tomography (SPECT) are only one step in appropriate use of imaging. Other steps include pretest clinical risk evaluation and optimal management responses. We sought to understand the link between AUC, risk evaluation, management, and outcome. METHODS: We used AUC to classify 1,199 consecutive patients (63.8 ± 12.5 years, 56% male) undergoing SPECT as inappropriate, uncertain, and appropriate. Framingham score for asymptomatic patients and Bethesda angina score for symptomatic patients were used to classify patients into high (≥5%/y), intermediate, and low (≤1%/y) risk. Subsequent patient management was defined as appropriate or inappropriate based on the concordance between management decisions and the SPECT result. Patients were followed up for a median of 4.8 years, and cause of death was obtained from the social security death registry. RESULTS: Overall, 62% of SPECTs were appropriate, 18% inappropriate, and 20% uncertain (only 5 were unclassified). Of 324 low-risk studies, 108 (33%) were inappropriate, compared with 94 (15%) of 621 intermediate-risk and 1 (1%) of 160 high-risk studies (P < .001). There were 79 events, with outcomes of inappropriate patients better than uncertain and appropriate patients. Management was appropriate in 986 (89%), and appropriateness of patient management was unrelated to AUC (P = .65). CONCLUSION: Pretest clinical risk evaluation may be helpful in appropriateness assessment because very few high-risk patients are inappropriate, but almost half of low-risk patients are inappropriate or uncertain. Appropriate patient management is independent of appropriateness of testing.

Exercise testing in asymptomatic patients after revascularization: are outcomes altered?

BACKGROUND: Although exercise echocardiography (ExE) of asymptomatic patients early (2 years after percutaneous coronary intervention [PCI] or 5 years after coronary bypass graft surgery [CABG]) after revascularization is considered inappropriate, the appropriateness of later testing is indeterminate. Treatment responses to positive test results in either setting have uncertain outcome implications. We sought to identify whether predictors of increased risk by ExE could lead to interventions that change outcome in asymptomatic patients with previous coronary revascularization. METHODS: Exercise echocardiography was performed in 2105 asymptomatic patients (mean [SD] age, 64 [10] years; 310 [15%] were women; 845 [40%] had a history of myocardial infarction; 1143 [54%] had undergone PCI and 962 [46%] had undergone CABG 4.1 [4.7] years prior to the ExE). Ischemia was identified as a new or worsening wall motion abnormality. Patients were followed for a mean (SD) period of 5.7 (3.0) years for cardiac mortality. The association of ischemia during ExE with survival was assessed using Cox proportional hazard models, and an interaction with revascularization was sought. RESULTS: Of 262 patients with ischemia (13%), only 88 (34%) underwent subsequent revascularization. Mortality (97 patients [4.6%]) was associated with ischemia (hazard ratio, 2.10; 95% CI, 1.05-4.19; P=.04) in groups tested both early (P=.03) and late (≥2 years after PCI or ≥ 5 years after CABG) (P=.001). However, the main predictors of outcome were clinical and stress testing findings rather than echocardiographic features. Subgroup analysis showed that asymptomatic patients without diabetes mellitus, with normal ejection fraction (≥50%), and normal exercise capacity (>6 METs [metabolic equivalent for task]) were unlikely to have a positive test result or events. Even high-risk patients did not seem to benefit from repeated revascularization. CONCLUSIONS: Asymptomatic patients who undergo ExE after coronary revascularization may be identified as being at high risk but do not seem to have more favorable outcomes with repeated revascularization. From a health economic standpoint, appropriateness of such testing must be carefully reviewed.

Impact of progression of diastolic dysfunction on mortality in patients with normal ejection fraction.

BACKGROUND: Diastolic dysfunction is an independent predictor of mortality in patients with normal left ventricular ejection fraction. There are limited data, however, on whether worsening of diastolic function is associated with worse prognosis. METHODS AND RESULTS: We reviewed clinical records and echocardiograms of consecutive patients who had baseline echocardiograms between January 1, 2005, and December 31, 2009, that showed left ventricular ejection fraction ≥55% and who subsequently had a follow-up echocardiogram within 6 to 24 months. Diastolic function was labeled as normal, mild, moderate, or severe dysfunction. All-cause mortality was determined by use of the Social Security Death Index. Kaplan-Meier survival analysis and Cox regression analysis with a proportional hazard model were performed to assess outcomes. A total of 1065 outpatients were identified (mean±SD age, 67.9±13.9 years; 58% male). Baseline diastolic dysfunction was present in 770 patients (72.3%), with mild being the most prevalent. On follow-up testing (mean±SD, 1.1±0.4 years), 783 patients (73%) had stable, 168 (16%) had worsening, and 114 (11%) had improved baseline diastolic function. Eighty-eight patients (8.3%) had a decrease in left ventricular ejection fraction to <55% and were more likely to have advanced diastolic dysfunction (P=0.002). After a mean±SD follow-up (from the second study) of 1.6±0.8 years, 142 patients (13%) died. On multivariate analysis, a decrease in left ventricular ejection fraction to <55% and any worsening of diastolic function were independently associated with increased risk of mortality (hazard ratio, 1.78; 95% confidence interval, 1.10-2.85; P=0.02; and hazard ratio, 1.78; 95% confidence interval, 1.21-2.59; P=0.003, respectively). CONCLUSION: In patients with normal baseline left ventricular ejection fraction, worsening of diastolic function is an independent predictor of mortality.

Alternative methods for the assessment of mechanical dyssynchrony using phase analysis of gated single photon emission computed tomography myocardial perfusion imaging.

Measurement of left ventricular (LV) mechanical dyssynchrony from single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) allows optimization of cardiac resynchronization therapy in heart failure patients. We compared the discriminatory ability and reproducibility of a new software method, Corridor 4DM (4DM) to the established method, Emory Cardiac Toolbox (ECTb) in normals and heart failure patients. LV dyssynchrony was measured in 100 control (Group 1) and 100 patients with LVEF <35% (Group 2) using time to peak thickening with first harmonic, fourth harmonic, and volume curve methods with the 4DM software, and compared to ECTb. Of the 3 4DM methods, first harmonic had the best correlation with the ECTb (R = 0.88, slope = 1.00, P < 0.0001, bias = -0.18° [95% CI: -20°; 16°] for phase standard deviation; and similarly for histogram bandwidth, while volume curve analysis had the greatest variation. The intra and inter-observer reproducibility for 4DM time to peak thickening with first harmonic was very good (R = 0.99, P < 0.0001 and coefficient of variability 10% [95% CI 9.2-12%] for intra-observer, and R = 0.97, P < 0.0001, coefficient of variability 16% [15-17%] for inter-observer, respectively). Finally, in patients with LVEF <35%, the area under the curve on receiver operator characteristic analysis was 0.93 [95% CI: 0.89-0.97] to detect significant mechanical dyssynchrony (i.e. standard deviation ≥43°) using 4DM versus ECTb. The 4DM-software provides an accurate and reproducible alternative method of dyssynchrony analysis of SPECT MPI for evaluation and management of heart failure.

Challenges in cardiac risk assessment in bariatric surgery patients.

Bariatric surgery has serious associated medical comorbidity and procedure-related risks and is thus considered an intermediate- to high-risk noncardiac surgery. Most patients referred for bariatric surgery have a low or very low functional capacity, making cardiac risk assessment imperative. Stress echocardiography has a high negative predictive value and can avoid some of the table weight and torso diameter problems associated with myocardial perfusion imaging. Echocardiograph contrast agents improve the ability to identify endocardial borders and assess ventricular wall motion and may be used with stress and nonstress imaging protocols. Single photon emission computer tomography (SPECT) imaging with attenuation correction, combined supine and prone imaging, use of technetium isotope, and positron emission tomography (PET) imaging may all provide some advantage for myocardial perfusion imaging for the obese patient.

Challenges in pulmonary risk assessment and perioperative management in bariatric surgery patients.

Bariatric surgery has serious associated medical comorbidity and procedure-related risks and is, thus, considered an intermediate-to-high-risk non-cardiac surgery. Altered respiratory mechanics, obstructive sleep apnea (OSA), and less often, pulmonary hypertension and postoperative pulmonary embolism are the major contributors to poor pulmonary outcomes in obese patients. Attention to posture and positioning is critical in patients with OSA. Suspected OSA patients requiring intravenous narcotics should be kept in a monitored setting with frequent assessments and naloxone kept at the bedside. Use of reverse Tredelenburg position, preinduction, maintenance of positive end-expiratory pressure, and use of continuous positive airway pressure can help improve oxygenation in the perioperative period.