Ischemic stroke in patients previously anticoagulated for non-valvular atrial fibrillation: Why does it happen? / Acidente vascular cerebral isquémico em doentes previamente anticoagulados por fibrilhação auricular não valvular: por que acontece?

INTRODUCTION: Oral anticoagulants have proved to be highly effective in preventing atrial fibrillation (AF)-related strokes. The occurrence of stroke despite oral anticoagulation is unexpected and little is known about the mechanisms responsible. The aim of this study was to assess possible mechanisms for stroke occurrence, such as poor treatment adherence and inappropriate dosage, in patients chronically anticoagulated for AF. METHODS: We performed a prospective observational study of 60 consecutive patients with non-valvular AF, chronically medicated with an oral anticoagulant and admitted due to ischemic stroke. Treatment adherence was assessed through the Brief Medication Questionnaire (BMQ) and the Medição da Adesão ao Tratamento (MAT) scales. Patient characteristics, stroke etiology, and appropriacy of anticoagulant dosage were also assessed. RESULTS: Patients' mean age was 78.6±8.0 years, and 51.7% were male. Overall, the proportion of patients with good adherence to anticoagulants was 63.3%. Adherent patients were more frequently illiterate (26.3% vs. 4.5%, p=0.012). The proportion of patients under vitamin K antagonists (VKAs) with good treatment adherence was significantly higher than that of patients under novel oral anticoagulants (NOACs) (83.3% vs. 54.8%, respectively, for BMQ, p=0.035). However, 91.7% of patients under VKAs presented an admission INR <2. Subtherapeutic prescriptions were found in 43% of patients under NOACs. CONCLUSION: In the majority of patients, stroke occurrence despite chronic anticoagulation appears to be explained by subtherapeutic dosage, poor treatment adherence or non-cardioembolic etiology, and not by inefficacy of the anticoagulants.

Who still remains at risk of arrhythmic death at time of implantable cardioverter-defibrillator generator replacement?

BACKGROUND: Implantable cardioverter-defibrillator (ICD) is associated with reduction in arrhythmic mortality. However, at the time of generator replacement (GR) some patients had not experienced therapies and had a different clinical profile. Therefore, the risk-benefit ratio of ICD may have changed. Our aim was to determine the proportion of patients with ICD implanted in primary prevention that maintain guideline-derived indications at the time of GR and assess predictors of therapies in the postreplacement period. We evaluate the long-term benefit of ICD after GR in nonischemic cardiomyopathy (NICM) versus ischemic cardiomyopathy (ICM). METHODS: We included 141 patients undergoing GR from 11/2009 to 7/2015. Patients were divided into: G1 - guideline congruent indication for ICD at the time of GR (left ventricular ejection fraction [LVEF] ≤ 35% or appropriate therapies) and G2 - guideline incongruent indication (patients without appropriate therapies and LVEF >35%). We also compared ICD benefit between ICM and NICM patients. RESULTS: Maintenance of guideline-driven indications for ICD (G1) was present in 68% of patients and 32% had recovery of LVEF and no ICD therapies at the time of GR (G2). After GR, G2 patients showed a lower rate of appropriate therapies (3% vs 33%, P < 0.01). LVEF ≤ 35% was the only independent predictor of appropriate therapies (OR 12.0, P < 0.01). In multivariate analysis, etiology of heart failure did not predict the arrhythmic risk. CONCLUSION: At the time of GR, a significant proportion of patients no longer met guideline indications for ICD and their need for therapies is reduced. The etiology of heart failure did not predict freedom from therapies.

Disruption of bioresorbable vascular scaffold struts due to loss of radial integrity: insights from optical coherence tomography.

Strut disruption of bioresorbable vascular scaffold is a known potential concern, although uncommon when adequate lesion preparation is achieved and nominal size of the scaffold is respected. It is usually difficult to detect with angiography and/or intravascular ultrasound. Three-dimensional reconstructions of optical coherence tomography facilitates understanding of complex luminal anatomy and configuration of stent struts, providing evaluation of stent integrity immediately after deployment and therefore optimization of the complex revascularization procedure. The present article reports a case where this image modality enabled successful use of a drug-eluting stent inside a bioresorbable vascular scaffold to restore the luminal integrity, jeopardized by struts disruption. This case highlights the need to better characterize coronary atherosclerotic disease complexity before considering bioresorbable vascular scaffold implantation. Optical coherence tomography imaging could be a useful tool for accurate selection of the most suitable lesions for bioresorbable stents and to guide the revascularization process, so that in the event of stent fracture it may be detected and managed in a timely fashion.