Faculty Bibliography

Using cardiac magnetic resonance, the presence of myocardial delayed contrast enhancement (DCE) has been described in the ventricular septum at the level of the right ventricular insertion points in patients with pulmonary hypertension (PH). The aim of this study was to investigate the prevalence, extent, and correlates of this finding. Septal DCE was evaluated in 55 patients with known or suspected PH of various causes. The extent of DCE was estimated visually with an insertion enhancement score (range 0 to 4) and quantified as DCE mass. The results were correlated with cine magnetic resonance and right-sided cardiac catheterization. Predictors of DCE were investigated using multivariate analysis. PH at rest was present in 42 patients (group 1) and absent in 13 (group 2). DCE was noted in 41 patients (97%) in group 1 and 3 (23%) in group 2 (p <0.0001). The extent of DCE was higher in group 1 than group 2 (median insertion enhancement score 3 vs 0, median DCE mass 8.7 vs 0 g, respectively; p <0.0001 for both). The extent of DCE showed moderate to good univariate correlations (r = 0.5 to 0.73) with pulmonary pressures and with right ventricular volumes, mass, and ejection fractions. In multivariate analysis, systolic pulmonary pressure was the only predictor of DCE. In conclusion, the presence of septal DCE at the right ventricular insertion points is common in PH of different causes, and the level of systolic pulmonary pressure elevation appears to be the main determinant of this finding.

Pharmacy benefit managers (PBMs), which generally administer prescription drug benefits as one component of an employer's or other sponsor's health insurance plan, have come under fire in recent years for turning profits at a time when consumer advocates and employers are struggling to contain the costs of health insurance and prescription drugs. Lawsuits alleging that PBMs are breaching certain fiduciary duties to the health plans they serve, however, have failed for the most part on grounds that PBMs are not "fiduciaries" under the Employee Retirement Income Security Act (ERISA). Moreover, states' attempts to regulate PBMs through legislation imposing fiduciary obligations and other related requirements have also generally failed for many different reasons. This Article examines the PBM industry, recent legal developments concerning PBMs' status as ERISA "fiduciaries", the arguments being made for and against stricter regulation of PBMs' business practices, and why litigation and legislation attempting to impose fiduciary obligations upon PBMs have generally failed. The authors conclude that it is market forces and competition, rather than litigation or legislation, that will effectively motivate PBMs to play a role in the cost containment of prescription drugs in the years ahead.

PURPOSE: To evaluate assignment of left ventricular (LV) myocardial segments to coronary arterial territories by using coregistered magnetic resonance (MR) imaging and multi-detector row computed tomography (CT) displays; to assess the accuracy of coregistered displays in determining the distribution of clinically important coronary artery disease (CAD) and regional effect of CAD on LV myocardium in patients with chronic ischemic heart disease (CIHD); and to determine the utility of coregistered displays in optimizing surgical revascularization planning. MATERIALS AND METHODS: This study was HIPAA compliant and was approved by the local Institutional Review Board, with waiver of informed consent. Twenty-six patients (19 men, seven women; age, 56 years +/- 12 [+/- standard deviation]) with CIHD underwent MR imaging assessment of myocardial viability and multi-detector row CT assessment of CAD on the same day. For coregistration, a population-based LV model was fit to each data set separately; models were then registered spatially. For data analysis, correspondence between coregistered displays and the 17-segment LV model for assessment of CIHD was evaluated, accuracy of using coregistered displays to evaluate the extent of CAD and myocardial disease was assessed, and utility of coregistered displays in optimizing surgical revascularization planning was determined. RESULTS: Coronary assignment for coregistered displays and the 17-segment LV model differed in 17% of myocardial segments. For the majority of patients, three segments (midanterolateral [62%], apical lateral [73%], and apical inferior [58%]) were discordant. Segments were supplied by the left anterior descending artery, a diagonal branch, or a ramus intermedius with diagonal distribution in all but one case. Coregistered displays were deemed concordant with selective coronary angiography and alternate myocardial imaging in all cases. Overall, surgical planning was potentially enhanced in 83% of cases because, compared with alternate imaging modalities, coregistered displays were believed to demonstrate the relationship between coronary arteries and underlying myocardial tissue more definitively and efficiently (for patients in whom surgery was performed) or more correctly and comprehensively (for a presumably better-tailored surgery). CONCLUSION: Assessment of CIHD can be improved by using coregistered displays that directly relate the condition of LV myocardium to the anatomy of the coronary arteries in individual patients.

PURPOSE: To evaluate six algorithms for segmenting non-viable left ventricular (LV) myocardium in delayed enhancement (DE) magnetic resonance imaging (MRI). METHODS: Twenty-three patients with known chronic ischemic heart disease underwent DE-MRI. DE images were first manually thresholded using an interactive region-filling tool to isolate non-viable myocardium. Then, six thresholding algorithms, based on the image intensity characteristics of either LV blood pool (BP), viable LV myocardium, or both, were applied to each image. For the Mean-2SD(BP) algorithm, thresholds were equal to the mean BP intensity minus twice its standard deviation. For the Mean + 2SD(Semi), Mean + 3SD(Semi), Mean + 2SD(Auto), and Mean + 3SD(Auto) algorithms, thresholds equaled the mean intensity of viable myocardium plus twice (or thrice, as denoted by the name) the standard deviation of intensity (subscripts denote how these values were determined: automatic or semi-automatic). For the Minimum Intensity algorithm, the threshold equaled the minimum intensity between the BP and LV myocardium mean intensities. Percent Scar was defined as the ratio of non-viable to total myocardial pixels in each image. Agreement between each algorithm and manual thresholding was assessed using Bland-Altman analysis. RESULTS: Mean Percent Scar was 25 +/- 16% by manual thresholding. Five of the six algorithms demonstrated mean bias within +/-3% (all except Mean+2SD(Auto)); however, limits of agreement (LoA) were large in general (range 12-36%). The best overall agreement was demonstrated by the Mean + 2SD(Semi) (bias, 0%; LoA, 12%) and Mean + 3SD(Semi)(bias, -3%; LoA, 14%) algorithms. CONCLUSION: On average, five of the six algorithms proved satisfactory for clinical implementation; however, in some images, manual correction of automatic results was necessary.

PURPOSE: To characterize the extent and distribution of left ventricular myocardial scar in delayed enhancement magnetic resonance imaging (MRI). MATERIALS AND METHODS: Delayed enhancement images from 18 patients were categorized into three groups based on myocardial scar appearance: discrete myocardial infarction (N = 10), diffuse fibrosis (N = 4), and circumferential endocardial scarring (N = 4). Images were segmented manually by two observers (twice by one observer) to identify nonviable myocardium. Scar was characterized by the following morphologic parameters: the relative area of nonviable myocardium (Percent Scar); a measure of scar cohesion (Patchiness); and the extent to which scar traversed the ventricle wall (Trans>50). RESULTS: The three scar parameters successfully discriminated between patient groups, although no one parameter was able to differentiate between all groups. The average bias between readers was approximately 3% for each parameter, and the average bias between repeated measurements was 1%. In addition, five patients exhibited regions of nonhyperenhanced nonviable myocardium that were expected to show hyperenhancement based upon their location within the infarct zone and appearance on cine images. CONCLUSION: Quantitative characterization of myocardial scar showed good interobserver and intraobserver agreement. However, the appearance of nonhyperenhanced scar in chronic ischemia is problematic for segmentation of delayed enhancement images.