Are SPECT MPI measures of dyssynchrony dyssynchronous?

BACKGROUND: Assessment of left ventricular mechanical dyssynchrony (LVMD) from gated SPECT myocardial perfusion imaging (MPI) aims to aid selection of patients for cardiac resynchronization therapy (CRT), using either the standard deviation of left ventricular phase (PSD) ≥ 43° or phase histogram bandwidth (HBW) of > 38° and > 30.6° in males and females, respectively. We observed dyssynchrony parameters might be affected by test type and alignment. METHODS: We reviewed 242 patients who underwent gated SPECT MPI with use of the Emory Cardiac Toolbox comparing PSD and HBW at rest and stress for Pearson correlation, and substitutability with Bland-Altman analysis. RESULTS: There is statistically significant difference in the mean PSD and HBW during rest vs stress (33.4 ± 17.4° vs 20.7 ± 13.5° and 97.7 ± 59.6° vs 59.4 ± 45.4°, respectively, P < 0.001). Proper valve plane alignment rendered smaller values (i.e., less dyssynchrony) in both phase SD and HBW (16.8 ± 13.5) vs (22.2 ± 14.7) (P = 0.011), and (47.0 ± 38.2) vs (60.7 ± 48.0) (P = 0.023), respectively. CONCLUSION: Proper alignment and test type, particularly low-dose rest vs high-dose stress, should be considered when assessing LVMD using SPECT MPI.

Racial disparities in left main stenting: insights from a real world inner city population.

BACKGROUND: Left main coronary artery (LMCA) disease is associated with significant cardiovascular mortality. The data on patient characteristics' predicting outcomes after LMCA revascularization is sparse. METHODS: A retrospective study of 227 patients with LMCA disease documented on coronary angiography from March 2000 to December 2008. Data included demographic variables, co-morbidities, cardiac function, and medications. Race was self-identified. The study outcome was a composite end-point including myocardial infarction (MI) and all-cause mortality. Cox proportional hazard analysis was performed to study the effect of various patient attributes including race and gender on the composite end-point. RESULTS: Baseline characteristics were specifically compared between individuals who had the study outcome versus those who did not. Mean age was higher in the group with study outcomes when compared to the group without any outcomes (64.3 ± 11.8 years versus 59.2 ± 13.6 years; p = 0.013). After the final multivariate regression analysis, only African American (AA) race and age were found to be independent predictors of adverse cardiac outcome at the end of the first year (race-hazard ratio (HR) 3.82, 95% confidence interval (CI) 1.38-10.62, p = 0.010; age-HR 1.08, 95% CI 1.04-1.13, p < 0.001) and at the end of the study (race-HR 2.71, 95% CI 1.44-5.10, p = 0.002; age-HR 1.03, 95% CI 1.01-1.08, p = 0.017). CONCLUSION: In our study of patients with unprotected LMCA disease, AA race, and age were significantly predictive of poor prognosis following revascularization, while gender had no predictive value in prognosticating cardiovascular mortality.

Impact of Area Deprivation Index on Coronary Stent Utilization in a Medicare Nationwide Cohort.

Area Deprivation Index (ADI) is a marker of neighborhood deprivation. This study investigates utilization of coronary bare-metal stent (BMS) and drug-eluting stent (DES) in Medicare patients across hospitals with varying ADI. Data were abstracted using Diagnosis-Related Group (DRG) codes 249 (BMS without major complications or comorbidities [MCC]), 246, and 247 (DES with and without MCC, respectively) from the 2011-2012 Medicare Provider Utilization and Payment Data Inpatient File, which was linked to American Hospital Association data (to determine bed size, location, ownership, teaching status), and ADI for each hospital zip code was obtained. Hospitals were divided into quintiles using ADI values: Quintile 1 (privileged) to Quintile 5 (deprived). Logistic regression was conducted to determine odds ratios (ORs) for DES utilization across ADI quintiles. There were 313,739 discharges with DRG codes 246 (52,839), 247 (203,928), and 249 (56,972). DES utilization was lower in the deprived quintile, irrespective of teaching status. It was lower in larger hospitals and hospitals with more annual stent discharges, urban locations and nongovernment not-for-profit institutes. Lower odds of DES utilization were found in Quintile 2 (OR-0.9, 95% confidence interval [CI] 0.87-0.93, P < 0.001), Quintile 3 (OR-0.89, 95% CI 0.86-0.92, P < 0.001), and Quintile 4 (OR-0.95, 95% CI 0.92-0.98, P = 0.001) versus Quintile 1 and there was no difference in utilization of DES in Quintile 5 (OR-1.01, 95% CI 0.98-1.04, P = 0.6) versus Quintile 1. Significant differences exist in DES utilization in a large, uniformly insured cohort based on neighborhood deprivation.

Impact of hospital and sociodemographic factors on utilization of drug-eluting stents in 2011-2012 Medicare cohort.

OBJECTIVE: Insurance status is a predictor of drug-eluting stent (DES) usage. Our study sought to determine the effect of hospital and sociodemographic characteristics on utilization of DES in nationwide inpatient discharges with uniform insurance (Medicare). METHODS: We linked data from the 2011 to 2012 Medicare discharges, 2011 Medicare hospital referral region (HRR) report (racial composition of each HRR), American Hospital Association (number of beds, rural/urban location, public/private status, and academic affiliation of hospitals), and American Community Survey 2011 (median income using zip code). We analyzed diagnosis-related group (DRG) codes 249 (bare metal stent without complications), 246, and 247 (DES with and without complications, respectively). Univariate and multivariable logistic regression was conducted to determine odds ratios (OR) for utilization of DES. RESULTS: There were 322,002 discharges with DRG codes 246 (54,279), 247 (209,365), and 249 (58,358) in our database. Higher odds of DES usage was observed in Hispanic dominant HRR(s) (OR: 1.37, 95% confidence interval [CI]: 1.33-1.42, P < 0.001) compared to Caucasian dominant HRR(s). DES utilization was similar in African-American and Caucasian dominant HRR (s). Higher odds of DES use was observed in median household income groups ≥$20,001 (OR: 1.07, 95% CI: 1.01-1.13, P - 0.03). Lower DES usage was observed in hospitals with higher total stent volume (quartile 4 vs. quartile 1: OR: 0.66, 95% CI: 0.63-0.69, P < 0.001) and for-profit hospitals (OR: 0.88, 95% CI: 0.85-0.92, P < 0.001). CONCLUSIONS: Our study findings suggest that there are significant differences in DES utilization in a national cohort of individuals with uniform insurance.

Role of Microalbuminuria in Predicting Cardiovascular Mortality in Individuals With Subclinical Hypothyroidism.

PURPOSE: Studies suggest that subclinical hypothyroidism (SCH) is related to cardiovascular mortality (CVM). We explored the role of microalbuminuria (MIA) as a predictor of long-term CVM in population with and without SCH with normal kidney function. MATERIALS AND METHODS: We examined the National Health and Nutrition Education Survey - III database (n = 6,812). Individuals younger than 40 years, thyroid-stimulating hormone levels ≥20 and ≤0.35mIU/L, estimated glomerular filtration rate <60mL/minute/1.73m2 and urine albumin-to-creatinine ratio of >250mg/g in men and >355mg/g in women were excluded. SCH was defined as thyroid-stimulating hormone levels between 5 and 19.99mIU/L and serum T4 levels between 5 and 12µg/dL. MIA was defined as urine albumin-to-creatinine ratio of 17-250mg/g in men and 25-355mg/g in women. Patients were categorized into the following 4 groups: (1) no SCH or MIA, (2) MIA, but no SCH, (3) SCH, but no MIA and (4) both SCH and MIA. RESULTS: Prevalence of MIA in the subclinical hypothyroid cohort was 21% compared to 16.4% in those without SCH (P = 0.03). SCH was a significant independent predictor of MIA (n = 6,812), after adjusting for traditional risk factors (unadjusted odds ratio = 1.75; 95% CI: 1.24-2.48; P = 0.002 and adjusted odds ratio = 1.83; 95% CI: 1.2-2.79; P = 0.006). MIA was a significant independent predictor of long-term all-cause (adjusted hazard ratio = 1.7, 95% CI: 1.24-2.33) and CVM (adjusted hazard ratio = 1.72, 95% CI: 1.07-2.76) in subclinical hypothyroid individuals. CONCLUSIONS: In a cohort of subclinical hypothyroid individuals, the presence of MIA predicts increased risk of CVM as compared to nonmicroalbuminurics with SCH. Further randomized trials are needed to assess the benefits of treating microalbuminuric subclinical hypothyroid individuals and impact on CVM.

Major electrocardiographic abnormalities and 25-hydroxy vitamin D deficiency: insights from National Health and Nutrition Examination Survey-III.

BACKGROUND: We explored the relationship between major electrocardiogram (ECG) abnormalities (mECG) and 25-hydroxy (25-OH) vitamin D deficiency (VDD) and the effect of mECG abnormalities on all-cause and cardiovascular mortality in a healthy cohort with 25-OH vitamin D insufficiency and deficiency. HYPOTHESIS: Lower levels of serum 25-OH vitamin D are associated with increased prevalence of mECG on resting ECG. METHODS: We identified 5108 individuals from the National Health and Nutrition Examination Survey-III. mECG abnormalities included: major Q-QS wave abnormalities, ST depression/elevation, negative T waves, Wolff-Parkinson-White pattern, and ventricular conduction defect. Our cohort was divided into 3 groups based on 25-OH vitamin D levels: Group 1 (referent): > 40 ng/mL; group 2 (insufficient): ≥ 20.01 to ≤ 40 ng/mL; and group 3 (deficient): ≤ 20 ng/mL. Logistic regression and Cox proportional hazards regression models were built. RESULTS: The prevalence of major ECG abnormalities across 25-OH vitamin D sufficiency, insufficiency, and deficiency was .9%, 11%, and 13 %, respectively (P = 0.01). VDD was an independent predictor of mECG abnormalities after adjusting for traditional risk factors (continuous variable odds ratio [OR]: 0.98, 95% confidence interval [CI]: 0.97-0.99, P = 0.007; categorical variable group 3 vs group 1 OR: 2.36, 95% CI: 1.1-5.12, P = 0.03). Baseline major ECG abnormalities were predictive of long-term all-cause (hazard ratio [HR]:1.52, 95% CI: 1.23-1.89), composite cardiovascular (HR: 1.7, 95% CI: 1.34-2.15), cardiovascular (HR: 1.64, 95% CI: 1.27-2.12), and ischemic heart disease mortality (HR: 1.98, 95% CI: 1.46-2.69) in individuals with 25-OH vitamin D levels ≤ 40 ng/mL. CONCLUSIONS: VDD is associated with increased prevalence of major ECG abnormalities. Well-structured trials are needed to assess progression/resolution of mECG abnormalities with vitamin D supplementation in deficient individuals.

Recurrent low-level troponin I elevation is a worse prognostic indicator than occasional injury pattern in patients hospitalized with heart failure.

BACKGROUND: Elevated troponin at baseline is associated with higher mortality in heart failure (HF) patients, but the prognostic role of recurrently elevated troponin is not well described. METHODS AND RESULTS: We performed chart reviews of 196 HF patients without acute coronary syndrome, with at least three Troponin I (TnI) measurements on different admissions. For the analyses, three sets of TnI values closest to baseline, one year and two years were selected for each patient. Based on the three sets of TnI, the lowest value of TnI (minimum), the highest value of TnI (maximum), median value of TnI and delta TnI (3rd TnI-baseline TnI) were derived for each patient. The study population of 196 patients had 632 person-year follow-up, consisted predominantly of elderly (68 ± 10 years) male patients (99%) with mean ejection fraction of 26 ± 13%. Using multivariate Cox proportional hazards model only minimum TnI, but not the maximum, median or delta of TnI values, was significantly associated with mortality (HR: 13.7, 95% CI: 3.7 to 50.8, p<0.001). As a categorical variable, minimum TnI value of >0.04ng/ml was also independently associated with mortality (p=0.01, HR=1.6, 95% CI: 1.1 to 2.3). CONCLUSIONS: In HF patients without acute coronary syndrome, the persistence of TnI elevation, even at low levels, is associated with a worse survival than sporadic TnI elevations of higher magnitude or any single elevation in TnI; and a recurrent elevation of TnI >0.04ng/ml portends a poor prognosis.

Atrial fibrillation post cardiac bypass surgery.

Atrial fibrillation occurs in 5-40% patients after coronary artery bypass graft surgery. Atrial fibrillation increases mortality and morbidity in the post-operative period. We sought to conduct a comprehensive review of literature focusing on pathophysiology, risk factors, prevention and treatment of post coronary artery bypass graft atrial fibrillation.

Purulent pericardial effusion from community-acquired methicillin-resistant Staphylococcus aureus.

Although the incidence of purulent pericarditis has decreased significantly in the modern antibiotic era, a high index of clinical suspicion should be maintained to diagnose this life-threatening illness at an early stage. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a global pathogen and notorious for its ability to cause infection in otherwise healthy individuals. However, it has been associated with purulent pericarditis only in some sporadic case reports. The authors describe a case of purulent pericardial effusion caused by CA-MRSA infection. To the best of our knowledge, this is only the fourth case of CA-MRSA pericarditis to be reported in English literature.

Four-dimensional deformable image registration using trajectory modeling.

A four-dimensional deformable image registration (4D DIR) algorithm, referred to as 4D local trajectory modeling (4DLTM), is presented and applied to thoracic 4D computed tomography (4DCT) image sets. The theoretical framework on which this algorithm is built exploits the incremental continuity present in 4DCT component images to calculate a dense set of parameterized voxel trajectories through space as functions of time. The spatial accuracy of the 4DLTM algorithm is compared with an alternative registration approach in which component phase to phase (CPP) DIR is utilized to determine the full displacement between maximum inhale and exhale images. A publically available DIR reference database (http://www.dir-lab.com) is utilized for the spatial accuracy assessment. The database consists of ten 4DCT image sets and corresponding manually identified landmark points between the maximum phases. A subset of points are propagated through the expiratory 4DCT component images. Cubic polynomials were found to provide sufficient flexibility and spatial accuracy for describing the point trajectories through the expiratory phases. The resulting average spatial error between the maximum phases was 1.25 mm for the 4DLTM and 1.44 mm for the CPP. The 4DLTM method captures the long-range motion between 4DCT extremes with high spatial accuracy.