Updates 09 August 2016
Anticoagulation in “Real-World” Atrial Fibrillation
The issue of suboptimal anticoagulation management in patients with nonvalvular atrial fibrillation (NVAF) has been highlighted in recent years, although the true impact upon patient outcomes has not been fully quantified.
A retrospective cohort study by Chan et al in this month’s Heart Rhythym used a population-wide database managed by the Hong Kong Hospital Authority. Patients newly diagnosed with NVAF during 2010–2013 were included in the analysis. A Cox proportional hazards regression model with 1:1 propensity score matching was used to compare the risk of ischemic stroke, intracranial hemorrhage, gastrointestinal bleeding, and all-cause mortality between patients receiving antiplatelet drugs and those receiving warfarin stratified by level of international normalized ratio (INR) control.
Of the 35,551 patients with NVAF, 30,294 (85.2%) had a CHA 2 DS 2 -VASc score of ≥2 (target group for anticoagulation). Of these, only 7029 (23.2%) received oral anticoagulants and 18,508 (61.1%) received antiplatelet drugs alone. There were 1541 (67.7%) of warfarin users who had poor INR control (time in therapeutic range [2.0–3.0] <60%). Patients receiving warfarin had comparable risks of intracranial hemorrhage (hazard ratio [HR] 1.24; 95% confidence interval [CI] 0.65–2.34) and gastrointestinal bleeding (HR 1.23; 95% CI 0.84–1.81) and lower risk of ischemic stroke (HR 0.40; 95% CI 0.28–0.57) and all-cause mortality (HR 0.45; 95% CI 0.36–0.57) than did patients receiving antiplatelet drugs alone. Good INR control was associated with a reduced risk of ischemic stroke (HR 0.48; 95% CI 0.27–0.86) as compared with poor INR control. Modeling analyses suggested that ~40,000 stroke cases could be potentially prevented per year in the Chinese population if patients were optimally treated.
The authors concluded that three-quarters of high-risk patients among this Chinese population with NVAF were not anticoagulated or had poor INR control. This study illustrates the continued need to improve the optimization of anticoagulation for stroke prevention in patients with atrial fibrillation.
MR and Aortic Regurgitation after TAVR
Residual aortic regurgitation (AR) following transcatheter aortic valve replacement (TAVR) is associated with greater mortality; yet, determining AR severity post-TAVR using Doppler echocardiography remains challenging. Cardiovascular magnetic resonance (CMR) is purported as a more accurate means of quantifying AR; however, no data exist regarding the prognostic value of AR as assessed by CMR post-TAVR.
This study included 135 patients from 3 centers. AR was quantified using regurgitant fraction (RF) measured by phase-contrast velocity mapping CMR at a median of 40 days post-TAVR, and using Doppler echocardiography at a median of 6 days post-TAVR. Median follow-up was 26 months. Clinical outcomes included mortality and rehospitalization for heart failure.
Moderate-severe AR occurred in 17.1% and 12.8% of patients as measured by echocardiography and CMR, respectively. Higher RF post-TAVR was associated with increased mortality (HR: 1.18 for each 5% increase in RF [95% confidence interval: 1.08 to 1.30]; p < 0.001) and the combined endpoint of mortality and rehospitalization for heart failure (hazard ratio: 1.19 for each 5% increase in RF; 95% confidence interval: 1.15 to 1.23; p < 0.001). Prediction models yielded significant incremental predictive value; CMR performed a median of 40 days post-TAVR had a greater association with post-TAVR clinical events compared with early echocardiography (p < 0.01). RF ≥30% best predicted poorer clinical outcomes (p < 0.001 for either mortality or the combined endpoint of mortality and heart failure rehospitalization).
Worse CMR-quantified AR was associated with increased mortality and poorer clinical outcomes following TAVR. Quantifying AR with CMR may identify patients with AR who could benefit from additional treatment measures.
Levosimendan and heart failure complicating ACS
Acute heart failure and/or cardiogenic shock are frequently triggered by ischemic coronary events. Yet, there is a paucity of randomized data on the management of patients with heart failure complicating acute coronary syndrome, as acute coronary syndrome and cardiogenic shock have frequently been defined as exclusion criteria in trials and registries. As a consequence, guideline recommendations are mostly driven by observational studies, even though these patients have a particularly poor prognosis compared to heart failure patients without signs of coronary artery disease.
A panel of 34 international experts in the fields of cardiology, intensive care medicine, internal medicine, and cardiovascular pharmacology convened in Munich on January 22nd, 2016 to review systematically the existing data on the use of levosimendan in acute heart failure complicating ACS.
In acute heart failure, and especially in cardiogenic shock related to ischemic conditions, vasopressors and inotropes are used. However, both pathophysiological considerations and available clinical data suggest that these treatments may have disadvantageous effects. The inodilator levosimendan offers potential benefits due to a range of distinct effects including positive inotropy, restoration of ventriculo-arterial coupling, increases in tissue perfusion, and anti-stunning and anti-inflammatory effects. In clinical trials levosimendan improves symptoms, cardiac function, hemodynamics, and end-organ function. Adverse effects are generally less common than with other inotropic and vasoactive therapies, with the notable exception of hypotension. The decision to use levosimendan, in terms of timing and dosing, is influenced by the presence of pulmonary congestion, and blood pressure measurements. Levosimendan should be preferred over adrenergic inotropes as a first line therapy for all ACS-AHF patients who are under beta-blockade and/or when urinary output is insufficient after diuretics. Levosimendan can be used alone or in combination with other inotropic or vasopressor agents, but requires monitoring due to the risk of hypotension.