[Low molecular weight heparin and non valvular atrial fibrillation]

Low molecular weight heparin (LMWH) are obtained through chemical or enzyme depolymerisation of unfractioned heparins (UFH). LMWHs present several advantages over UFH: they exhibit a smaller interindividual variability of the anticoagulant effect, they have a greater bioavailability, a longer plasma half-life and do not require monitoring of the anticoagulant effect. LMWH have restrictive indications in AF patients, cardioversion (II level C and TEE for ACC/AHA/ESC and 2C for ACCP guidelines) or use as a bridge therapy (IIB, level C for ACC/AHA/ESC). The ACE study (Anticoagulation for cardioversion using enoxaparin), showed a reduction, though not statistically significant, of 42% of the composite end point (embolic event, major bleeding and death) 2.8% under enoxaparin vs. 4.8 % under conventional treatment, relative risk 0.58, CI 95% 0.23-1.46). Other studies, using dalteparin, confirmed that an anticoagulant treatment using LMWH followed by warfarin was at least as good as conventional management. ACUTE II (Assessment of cardioversion using transesophageal echochardiography), a randomized multicenter trial, compared the efficacy and tolerance of enoxaparin (1 mg/kg every 12 hours) and UFH in 155 patients eligible for a TEE-guided cardioversion. These patients were administered LMWH or UFH for 24 hours before TEE or cardioversion. There were no significative differences regarding the incidence of the study end points, in particular stroke and bleeding, and no death occurred. HAEST (Heparin in acute embolic stroke trial), a randomized, placebo-controlled, double blind trial failed to show the LMWH superiority over aspirin in patients with acute ischemic stroke and atrial fibrillation. Finally, LMWH have been proposed as a bridge therapy in patients under chronic VKA prior to surgery or invasive procedures. This strategy resulted in a low rate of thromboembolic events and major bleedings.

Clinical characteristics and mid-term prognosis of acute coronary syndrome in HIV-infected patients on antiretroviral therapy

OBJECTIVES

Acute coronary syndromes (ACSs) and coronary artery disease are emerging complications in HIV-infected patients on highly active antiretroviral treatment. The aim of this study was to determine the mid-term prognosis of ACS in HIV-infected patients.

METHODS

We evaluated the clinical characteristics and follow-up profile [38+/-15 months; mean+/-standard deviation (SD)] of ACS in 20 HIV-infected patients (mean +/-SD: age 44+/-8 years; range 35-65 years). All had coronary angiograms performed mean time 3+/-48 h after the onset of symptoms.

RESULTS

Eighteen patients were on antiretroviral therapy, of whom 13 patients were on regimens including protease inhibitors (mean duration+/-SD: 19+/-13 months). Fifteen patients had a first episode of ST segment elevation ACS and five had non-ST segment elevation ACS. Tobacco consumption (80%) and hypercholesterolaemia (50%) were the most frequent cardiovascular risk factors. During initial hospitalization, four patients were treated with thrombolysis, two had primary coronary angioplasty and seven had secondary coronary angioplasty. At follow up, 10 patients (50%) had had 18 cardiovascular events: one cardiovascular death, seven episodes of recurrent myocardial ischaemia in four patients, three pulmonary oedemas in two patients, and seven revascularization procedures in five patients.

CONCLUSIONS

This preliminary report highlights the risk of ACS and related complications in HIV-infected patients and raises questions regarding the implications of antiretroviral treatment.

Œdème pulmonaire aigu lors d’une menace d’accouchement prématuré : rôle de la tocolyse par la nicardipine

Beta adrenergic agonists are still used as first line treatment for preterm labor in many institutions, but their side effects lead to use alternative tocolytic drugs such as calcium channel blockers. We report three cases of pulmonary edema during preterm labor associated with the use of calcium channel blocker, intravenous nicardipine, widely used for tocolysis in France. In this article, potential mechanisms of this severe complication are briefly discussed: pregnancy-induced overload, deleterious hemodynamic effects of calcium channel blockers, concomitant administration of calcium channel blockers and/or beta-agonists and finally concomitant administration of physiological saline and/or glucocorticoids. Based on our experience, we recommend avoiding the association of calcium channel blockers and beta-agonists for preterm labor. Nicardipine, if used, should be administered at an adjusted dose with electric syringe to reduce volume infusion.

[Preventing cerebrovascular accidents during atrial fibrillation]

Atrial fibrillation, the most commonly encountered arrhythmia in clinical practice, is associated with substantial morbidity and mortality. Its incidence and prevalence are increasing, and it represents a growing clinical and economic burden. Recent research has highlighted new approaches to both pharmacological and non-pharmacological management. Pooled data from trials comparing antithrombotic treatment with placebo show that warfarin reduces the risk of stroke by 62% and that aspirin alone reduces the risk by 22%. Overall, in high-risk patients, warfarin was better than aspirin in preventing strokes, with a relative risk reduction of 36%, but the risk of major hemorrhage with warfarin was twice that with aspirin. Anticoagulation treatment needs to be tailored individually for patients on the basis of age, comorbidities, and contraindications. However, warfarin remains under-prescribed in clinical practice, for reasons related to patients (comorbidities) and physicians. The limitations of warfarin treatment have prompted the development of new anticoagulants with predictable pharmacokinetics that do not require as frequent monitoring. Ximelagatran, an oral direct thrombin inhibitor, was compared with warfarin in the SPORTIF program, which found both agents to be broadly effective in the prevention of embolic events, but observed abnormal liver function tests in 6% of patients on ximelagatran. Liver function monitoring during treatment is thus needed. Idraparinux, a factor Xa inhibitor administered by once weekly subcutaneous injections, is being evaluated in patients with atrial fibrillation. The ACTIVE trial is currently assessing the role of aspirin plus clopidogrel, compared with adjusted dose warfarin, in the prevention of vascular events in high-risk patients with atrial fibrillation. Angiotensin-converting enzyme inhibitors and angiotensin II receptor-blocking drugs interfere with atrial remodeling and show promise in atrial fibrillation, as suggested in the LIFE trial. Preliminary studies suggest that statins may reduce the risk of recurrence after electrical cardioversion. Finally, percutaneous methods for occlusion of the left atrial appendage are currently under investigation in patients at high risk of thromboembolism but with contraindications for chronic warfarin.