Updates 28 June 2016
Aspirin and Risk of Recurrent Stroke After Initial Cerebral Ischaemic Event.
Aspirin is widely used for secondary prevention of cerebro-vascular ischaemic events, but the time course of benefit after an initial TIA or minor stroke has not been clearly defined. In a meta-analysis of 15,778 participants in 12 clinical trials, Rothwell et al describe the time course and magnitude of benefit of aspirin after an initial TIA or minor stroke.
Aspirin reduced 6 weeks risk of any recurrent ischaemic stroke by 60% and 12 week risk by 54%. The greatest benefit was observed within the two weeks after the initial event. Aspirin also reduced the risk of disabling stroke at 6 and 12 weeks after the initial event. Aspirin was not associated with an increase in risk of intracerebral haemorrhage during the 12 weeks after the initial event.
The absolute risk of recurrent ischaemic stroke decreased with time after the initial event and after 12 weeks there was no significant reduction in recurrent ischaemic events for patients receiving aspirin compared to controls.
The addition of dipyridamole to aspirin had no effect on risk of recurrent ischaemic stroke in the 12 weeks after the initial event, however the addition of dipyridamole to aspirin did significantly reduce the risk of recurrent stroke after 12 weeks, particularly reducing the risk of disabling or fatal stroke.
The authors conclude that benefit of aspirin is greatest early after an initial TIA or minor stroke and consideration should be given to immediate use by patients after initial symptoms. The addition of dipyridamole to aspirin after 12 weeks appears to improve long-term outcomes.
Body Mass Index in Late Adolescence and Cardiovascular Death in Adulthood
Overweight and obesity are associated with increased cardiovascular mortality and morbidity. The BMI threshold and age at which cardiovascular risk begins to rise has not yet been defined. In a study of 2.3 million Israeli adolescents, Twig et al report in the NEJM that there was a graded increase in risk of later cardiovascular events as BMI in adolescents increased and that the increase in cardiovascular risk began when BMI was in the 50th to 74th percentiles (ie within currently accepted normal range).
During over 25 million patient years of follow-up for men and over 16 million patient years for women, there were 2918 cardiovascular deaths (2633 men, 285 women). Rates of death per person-year were lowest for those with adolescent BMI in the 25th to 49th percentiles, with higher rates among those with BMI below the 5th percentile. The incidence of cardiovascular death increased from 0.567 per 10,000 patient years for those with BMI in 25th to 49th percentile to 0.675, 0.824, 1.019 and 1.545 for those with BMI in the 50th to 74th, 75th to 84th, 85th to 94th and >95th percentiles respectively. Risk of non-cardiovascular death also increased with BMI.
the authors conclude that an increased BMI in late adolescence, even within the currently accepted normal range, was strongly associated with cardiovascular mortality in young adulthood or midlife, although they could not determine whether an increased BMI in adolescence is an independent risk factor, is mediated by adult obesity, or both.
Survival After Extracorporeal Membrane Oxygenation in Critically Ill Adults
Extracorporeal membrane oxygenation (ECMO) is increasingly used to support critically ill patients with cardiovascular shock and/or acute pulmonary failure. The outcomes for patients receiving ECMO support for coronary artery bypass grafting, myocardial infarction/cardiogenic shock, trauma or infection/septic shock are described by Chang et al in Circulation.
Among 4227 patients (age 57 ± 17 years) receiving ECMO over a ten years period, mortality at 1 month and 1 year was 59.8% and 76.5% respectively. Cumulative survival decreased from > 90% for those on ECMO for 2 days or less to <20% for those on ECMO for 3 days or more. Patients requiring ECMO for myocardial infarction/cardiogenic shock had poorer survival at 30 days and 1 year than did those requiring ECMO for other indications, although the differences were small.
The authors concluded that, given the critical condition of patients requiring ECMO, an average survival to hospital discharge of 35% could be deemed an immediate success, however further examination of long term outcomes after ECMO, including identification of factors determining long-term outcome, as well as cost-effectiveness, are required.
Left Atrial Appendage Morphology and Risk of Embolic Stroke with Atrial Fibrillation
The risk of thromboembolic events (TE) with chronic atrial fibrillation is a major indicator for anticoagulation, especially in older patients. In recent years, the different morphologies of the left atrial appendage (LAA) have been better appreciated. A meta-analysis by Lupercio et al published in Heart Rhythm examined that relation between LAA morphology and risk of TE in 2596 patients with non-valvular AF, of whom 84% had a CHA2DS2VASc score <2.
The morphology of the LAA has been described as: chicken wing, cauliflower, windsock and cactus. Morphology can be determined by transesophageal echocardiography, cardiac CT or cardiac MRI.
Among the eight studies analysed the prevalence of different LAA morphologies was variable (chicken-wing in 13 to 52%; cauliflower in 3 to 40%; windsock in 10 to 37% and cactus in 5 to 38%).
Patients with chicken wing LAA morphology had 54% lower TE risk than those with other LAA morphologies (OR = 0.46; CI = 0.36 – 0.58). The lower TE risk with chicken wing LAA morphology was also observed in secondary comparisons with each of the other morphologies.
The authors conclude that LAA morphology may be a useful independent predictor of TE risk in patients with non-valvular AF and propose a novel management algorithm for anticoagulation, including LAA morphology as a decision tool, for patients with CHA2DS2VASc score <2.