Prospective study of ABO blood type and the risk of pulmonary embolism in two large cohort studies

Prior studies have suggested an association of ABO blood type and the risk of venous thromboembolism; however, most studies were retrospective and lacked important covariates or validated endpoints. Moreover, risk estimates varied widely across studies. Therefore, we prospectively examined the association of blood type and the risk of incident pulmonary embolism (PE) in two large cohort studies, the Nurses' Health Study and Health Professionals Follow-up Study. During 1,010,378 person-years of follow-up among 77,025 women and 30,105 men, 499 participants developed PE. Compared to those with O-blood type, participants with non-O blood type had multivariable-adjusted hazard ratios (HR) of 1.86 (95% CI, 1.35-2.57) for idiopathic PE, 1.29 (95% CI, 1.03-1.62) for non-idiopathic PE, and 1.46 (95% CI, 1.22-1.76) for any PE. Hazard ratios were similar for participants with blood types A, B, and AB. Age-adjusted absolute rates of idiopathic PE over 10 years of follow-up differed by blood type: 0.11% for O, 0.20% for A, 0.19% for AB, and 0.21% for B. For idiopathic PE, the population attributable fraction was 33% for inheritance of non-O blood type. Among past and current smokers, participants with non-O vs. O-blood type had a HR for idiopathic PE of 2.56 (95% CI, 1.61-4.08). Among never smokers, the HR for idiopathic PE was 1.30 (95% CI, 0.82-2.05; P interaction=0.04). In two large, prospective cohorts, ABO blood type was significantly associated with the risk of idiopathic and non-idiopathic PE, with even greater risk for idiopathic PE among current and past smokers with non-O blood type.     

Model-based region-of-interest selection in dynamic breast MRI

Magnetic resonance imaging (MRI) is emerging as a powerful tool for the diagnosis of breast abnormalities. Dynamic analysis of the temporal pattern of contrast uptake has been applied in differential diagnosis of benign and malignant lesions to improve specificity. Selecting a region of interest (ROI) is an almost universal step in the process of examining the contrast uptake characteristics of a breast lesion. We propose an ROI selection method that combines model-based clustering of the pixels with Bayesian morphology, a new statistical image segmentation method. We then investigate tools for subsequent analysis of signal intensity time course data in the selected region. Results on a database of 19 patients indicate that the method provides informative segmentations and good detection rates.     

Death from high‐risk prostate cancer versus cardiovascular mortality with hormonal therapy

BACKGROUND:

Randomized trials have demonstrated improved survival when hormonal therapy (HT) is added to radiation therapy (RT) for high‐risk prostate cancer. However, it is still unknown whether men who have a history of myocardial infarction (MI) or MI risk factors achieve a superior outcome from HT.

METHODS:

A Markov decision analysis model was used to compare quality‐adjusted life expectancy (QALE) in men aged 50, 60, and 70 years who received RT and no HT, 6 months of HT (short‐term), or 3 years of HT (long‐term) for high‐risk prostate cancer stratified by cardiac risk group.

RESULTS:

In men with a history of MI, there was a decrease of 0.1 to 0.2 quality‐adjusted life years and 0.5 to 0.6 quality‐adjusted life years across all ages with short‐term HT and long‐term HT, respectively, compared with no HT. In men without MI, receipt of short‐term or long‐term HT was associated with a QALE benefit versus no HT in all cohorts. Among men without MI, the optimal duration of HT was a function of age and the number of MI risk factors. Long‐term HT improved QALE (range, 1.4‐5.4 years) for men aged 50 or 60 years except those with MI; whereas, for men aged 70 years with 4 cardiac risk factors, short‐term and long‐term HT yielded identical QALE.

CONCLUSIONS:

Men who received RT for high‐risk prostate cancer and had a history of MI experienced net harm when they received HT. Men without MI gained a QALE benefit from HT, even if they had up to 4 cardiac risk factors. The optimal duration of HT is a function of patient age and the number of cardiac risk factors. Cancer 2013. © 2013 American Cancer Society.     

The effect of certification and preparation on teacher quality

To improve the quality of the teacher workforce, some states have tightened teacher preparation and certification requirements while others have eased requirements and introduced "alternative" ways of being certified to attract more people to teaching. Donald Boyd, Daniel Goldhaber, Hamilton Lankford, and James Wyckoff evaluate these seemingly contradictory strategies by examining how preparation and certification requirements affect student achivement. If strong requirements improve student outcomes and deter relatively few potential teachers, the authors say, then they may well be good policy. But if they have little effect on student achievement, if they seriously deter potential teachers, or if schools are able to identify applicants who will produce good student outcomes, then easing requirements becomes a more attractive policy. In reviewing research on these issues, the authors find that evidence is often insufficient to draw conclusions. They do find that highly selective alternative route programs can produce effective teachers who perform about the same as teachers from traditional routes after two years on the job. And they find that teachers who score well on certification exams can improve student outcomes somewhat. Limited evidence suggests that certification requirements can diminish the pool of applicants, but there is no evidence on how they affect student outcomes. And the authors find that schools have a limited ability to identify attributes in prospective teachers that allow them to improve student achievement. The authors conclude that the research evidence is simply too thin to have serious implications for policy. Given the enormous investment in teacher preparation and certification and given the possibility that these requirements may worsen student outcomes, the lack of convincing evidence is disturbing. The authors urge researchers and policymakers to work together to move to a more informed position where good resource decisions can be made.     

Plasma renin substrate, renin activity, and aldosterone levels in a sample of oral contraceptive users from a community survey

Fasting plasma renin substrate (PRS), plasma renin activity (PRA), plasma aldosterone (PA), and blood pressure (BP) levels were measured from 212 apparently healthy normotensive nonpregnant white women aged 21 to 39 years, selected on the basis of oral contraceptive (OC) use of nonuse in 1976 following a community survey in East Boston. The mean PRS level was 7118 ng/dl among OC users and 1935 ng/dl among nonusers (p less than 0.0001). In contrast, mean PRA was 2.9 ng of angiotensin 1 per milliliter per hour among users and 3.0 ng of angiotensin l/ml/hr among nonusers (p = NS); mean PA levels were 26.2 ng/dl and 25.4 ng/dl, respectively (p = NS). Mean systolic BPs were 113.8 mm Hg among current OC users and 111.2 mm Hg among nonusers (p = 0.078); diastolic BPs were 68.5 and 68.9, respectively (p = NS). These data indicate a greater than three-fold increase in PRS among current OC users compared to nonusers, with virtually identical PRA and PA levels. The data indicate that normotensive women using OCs maintain normal PRA and PA levels despite marked elevations in PRS.     

Trends in management and outcomes of pulmonary embolism with a multidisciplinary response team

Journal of Thrombosis and Thrombolysis - Multidisciplinary pulmonary embolism (PE) response teams have garnered widespread adoption given the complexities of managing acute PE and provide a...     

Separation of water and fat MR images in a single scan at .35 T using „sandwich”︁ echoes

A method was developed for separation of water and fat MR images in a single scan with correction of static field inhomogeneity. The imaging sequence uses a single radiofrequency (RF) echo that is ?sandwiched”? between two gradient echoes. The gradient echoes are used to determine the B_o distribution and to produce out-of-phase images after phase correction using the field map. An algorithm was developed to unwrap the phase images for quantitating the B_o inhomogeneity. To account for differences in geometric distortion between the RF echo image and the gradient echo images due to the reversal of the read gradients, methods were developed to correct the images before the calculation of the final water and fat images. The proposed technique was implemented at .35 T. Both phantom and human images were acquired using the method. It is shown that water- and fat-separated images can be obtained in a single scan using the ?sandwich”? echoes in the presence of a relatively large B_o inhomogeneity.     

Delayed intrinsicoid deflection: Electrocardiographic harbinger of heart disease

Delayed intrinsicoid deflection (DID) is an emerging electrocardiogram (ECG) marker of major clinical significance that is increasingly getting attention. Intrinsicoid deflection measures ventricular depolarization in the initial portion of the QRS complex, and DID is defined as an R wave peak time of ≥50 ms in leads V₅ and V₆. Prior studies have identified an independent association between DID and cardiovascular conditions such as left ventricular hypertrophy, heart failure, and sudden cardiac death. The exact mechanism that results in DID remains unknown. Animal models indicate that DID may result from abnormal calcium and potassium conductance as well as extracellular matrix remodeling. DID remains an ECG marker of interest given its potential predictive value of underlying cardiovascular pathology and adverse events. This review provides an update on the proposed mechanisms and associations, as well as the clinical and research implications of DID.     

Uses of low-molecular-weight heparin

Low-molecular-weight-heparin fractions are prepared from standard unfractionated heparin and are thus similar to unfractionated heparin in many aspects. The main advantages of this new class of antithrombotic agents as compared with unfractionated heparin are: (1) an improved bioavailability and a prolonged half-life, which alleviate cumbersome laboratory monitoring and may permit one single daily subcutaneous injection; (2) an improved efficacy-to-safety ratio, with less bleeding despite similar or improved efficacy. While low-molecular-weight heparin should replace unfractionated heparin for preventing postoperative thromboembolism, some unresolved issues remain to be addressed in specific trials before low-molecular-weight heparin can generally replace unfractionated heparin for all indications. These issues include the use of low-molecular-weight heparin in patients with arterial thrombosis, unstable angina, or myocardial infarction (usually in conjunction with thrombolytic treatment), and in patients with symptomatic pulmonary embolism, as well as formal cost-effectiveness analyses substantiating the advantages of the new agents. The potential of using low-molecular-weight-heparin outpatient treatment of established deep-vein thrombosis should be scrutinized from an economic and logistic point of view because two large-scale controlled trials have suggested both efficacy and safety.