Journal of the New Zealand Medical Association, 11-May-2012, Vol 125 No 1354
Men are more commonly affected with coronary artery disease than women. This study explores the role of the Y chromosome in coronary artery disease in the context of this sexual inequity.
The researchers genotyped 11 markers of the male-specific region of the Y chromosome in 3233 biologically unrelated British men from three cohorts. Each Y chromosome was tracked back into one of the 13 ancient lineages defined as haplogroups. Of nine haplogroups identified, two (R1b1b2 and I) accounted for roughly 90% of the Y chromosome variants among British men. Carriers of haplogroup I had about a 50% higher age-adjusted risk of coronary artery disease than did men with other Y chromosome lineages. They speculate that this haplogroup interconnects with common genes related to inflammation and immunity which have a strong relevance to atherosclerosis and may explain the higher incidence of coronary artery disease in this cohort.
Apparently simulated laboratory studies suggest a dose–response relationship between cannabis use and reduced driving skills. This study is a meta-analysis of nine studies which compare accident rates between cannabis users and non-users. Cannabis use was documented by toxicology or self reporting. Only motor vehicle collisions resulting in serious injury or death were included. The authors report an almost two-fold (odds ratio 1.92) increase in the risk of serious accident in the cannabis users. They note that they had insufficient toxicological data to measure any dose–response effect. They speculate that cannabis may also be relevant in minor collisions.
The US Food and Drug Administration warned of this possibility in 2010. Hence this report which prospectively examined 79,899 postmenopausal women enrolled in the US Nurse’s Health Study who provided data on the use of PPIs and other risk factors biennially since 2000 and were followed through to 1 June 2008.
During the follow-up there were 893 hip fractures with an absolute risk of 2.2 events per thousand person years amongst the PPI users compared with 1.51 events in non-users. It is of note that cigarette smoking is involved in the equation and non-smoking PPI users did not have an increased risk of fracture.
Cardiovascular magnetic resonance (CMR) versus single-photon emission computed tomography (SPECT) in the diagnosis of coronary heart disease
In this prospective trial, patients with suspected angina pectoris and at least one cardiovascular risk factor were scheduled for CMR, SPECT, and invasive X-ray coronary angiography.
39% of 752 patients had significant coronary disease identified by angiography. For CMR the sensitivity was 86.5%, and 66.5% for SPECT, a significant difference. Currently SPECT is the most widely used test for the assessment of myocardial ischaemia but this report strongly suggests that CMR is better. It also does not expose patients to ionising radiation. On the other hand, CMR has limitations—cost, patient claustrophobia, some patients will have incompatible cardiac devices (pacemakers) and some with renal impairment may not tolerate this gadolinium used as a CMR image enhancer.
The authors of this study note that a fixed-dose regimen of rivaroxaban, an oral factor Xa inhibitor, has been shown to be as effective as standard anticoagulant therapy for the treatment of deep-vein thrombosis, without the need for laboratory monitoring.
They speculate that such a regimen may be equally effective in the management of pulmonary embolism and have conducted an appropriate randomised study. They randomised 4832 patients who had acute pulmonary embolism with or without deep vein thrombosis to either rivaroxaban (15 mg twice daily for 3 weeks, followed by 20 mg once daily) or standard therapy with enoxaparin followed by an adjusted-dose vitamin K antagonist for 3, 6, or 12 months.
Rivaroxaban proved to be non-inferior to the standard treatment for efficacy. There was less bleeding seen in the rivaroxaban cohort. It is noted that with no need for therapeutic injections or monitoring of laboratory results there may well be economic benefits as well.
N Eng J Med 2012;366:1287–97.
issue | Search journal |
Archived issues | Classifieds
| Hotline (free ads)
Subscribe | Contribute | Advertise | Contact Us | Copyright | Other Journals