Novel oral anticoagulants: focus on stroke prevention and treatment of venous thrombo-embolism

Anticoagulation for the long-term treatment and prevention of thrombo-embolic diseases as well as for stroke prevention in atrial fibrillation (AF) has been accomplished by vitamin K antagonists for the last half century. Although effective under optimal conditions, the imminent risk of a recurrent event vs. the risk of bleeding due to the narrow therapeutic window, numerous food- and drug interactions, and the need for regular monitoring complicate the long-term use of these drugs and render treatment with these agents complicated. As a result, novel anticoagulants which selectively block key factors in the coagulation cascade are being developed. The efficacy and safety of the direct thrombin inhibitor dabigatran etexilate, as well as of the selective factor Xa inhibitors rivaroxaban and apixaban, have been demonstrated in Phase III trials for stroke prevention in AF and the treatment and secondary prophylaxis of venous thrombo-embolism. This review summarizes the results from recently published pivotal clinical trials and discusses the opportunities as well as uncertainties in the clinical applications of these novel agent

Statin use after acute myocardial infarction by patient complexity: Are the rates right?

Reprinted with permission of the publisher.Background: Guidelines suggest statin use after acute myocardial infarction (AMI) should be close to universal in patients without safety concerns yet rates are much lower than recommended, decline with patient complexity, and display substantial geographic variation. Trial exclusions have resulted in little evidence to guide statin prescribing for complex patients. Objective: Assess the benefits and risks associated with higher rates of statin use after AMI by baseline patient complexity. Research Design: Sample includes Medicare fee-for-service patients with AMIs in 2008-2009. Instrumental variable estimators using variation in local area prescribing patterns by statin-intensity as instruments were used to assess the association of higher statin prescribing rates by statin-intensity on 1-year survival, adverse events, and cost by patient complexity. Results: Providers appear to have individualized statin use across patients based on potential risks. Higher statin rates for non-complex AMI patients were associated with increased survival rates with little added adverse event risk. Higher statin rates for complex AMI patients were associated with tradeoffs between higher survival rates and higher rates of adverse events. Conclusions: Higher rates of statin use for non-complex AMI patients are associated with outcome rate changes similar to existing evidence. For the complex patients in our study, who were least represented in existing trials, higher statin-use rates were associated with survival gains and higher adverse event risks not previously documented. Policy interventions promoting higher statin-use rates for complex patients may need to be re-evaluated taking careful consideration of these tradeoffs.This project was supported by an Agency for Healthcare Research and Quality grant (1R21HS019574-01) under the American Recovery and Reinvestment Act of 2009

Insulin Augmentation of Glucose-Stimulated Insulin Secretion Is Impaired in Insulin-Resistant Humans

Type 2 diabetes (T2D) is characterized by insulin resistance and pancreatic β-cell dysfunction, the latter possibly caused by a defect in insulin signaling in β-cells. We hypothesized that insulin’s effect to potentiate glucose-stimulated insulin secretion (GSIS) would be diminished in insulin-resistant persons. To evaluate the effect of insulin to modulate GSIS in insulin-resistant compared with insulin-sensitive subjects, 10 participants with impaired glucose tolerance (IGT), 11 with T2D, and 8 healthy control subjects were studied on two occasions. The insulin secretory response was assessed by the administration of dextrose for 80 min following a 4-h clamp with either saline infusion (sham) or an isoglycemic-hyperinsulinemic clamp using B28-Asp-insulin (which can be distinguished immunologically from endogenous insulin) that raised insulin concentrations to high physiologic concentrations. Pre-exposure to insulin augmented GSIS in healthy persons. This effect was attenuated in insulin-resistant cohorts, both those with IGT and those with T2D. Insulin potentiates glucose-stimulated insulin secretion in insulin-resistant subjects to a lesser degree than in normal subjects. This is consistent with an effect of insulin to regulate β-cell function in humans in vivo with therapeutic implications

Reduction of Experimental Myocardial Infarct Size by Corticosteroid Administration

The influence of the administration of pharmacologic doses of hydrocortisone on the extent and severity of acute myocardial ischemic injury and on subsequent necrosis after acute coronary occlusion was investigated in 28 dogs. In order to study acute myocardial injury, repeated epicardial electrocardiograms were recorded from 10 to 15 sites on the anterior surface of the left ventricle. Average ST segment elevation (ST) and the number of sites in which ST segment elevation exceeded 2 mV (NST), indices of the magnitude and extent of myocardial injury, respectively, were analyzed at 30 and 60 min after coronary occlusion. In the control group ST and NST did not change significantly in this time interval while in the treated group, which received 50 mg/kg hydrocortisone just after the 30 min recording, ST fell from 3.5+/-0.8 to 1.1+/-0.4 mV (P 2 mV) in the control group showed histologic changes compatible with early myocardial infarction in 96% of specimens, while this occurred only in 61% and 63% of specimens, respectively, in the treated groups, showing that over one third of the sites were protected from undergoing necrosis due to the intervening hydrocortisone treatment. Thus pharmacological doses of hydrocortisone prevent myocardial cells from progressing to ischemic necrosis even when administration is initiated 6 h after coronary occlusion

Valsartan for attenuating disease evolution in early sarcomeric hypertrophic cardiomyopathy: the design of the Valsartan for Attenuating Disease Evolution in Early Sarcomeric Hypertrophic Cardiomyopathy (VANISH) trial

Background: Hypertrophic cardiomyopathy (HCM) is often caused by sarcomere gene mutations, resulting in left ventricular hypertrophy (LVH), myocardial fibrosis, and increased risk of sudden cardiac death and heart failure. Studies in mouse models of sarcomeric HCM demonstrated that early treatment with an angiotensin receptor blocker (ARB) reduced development of LVH and fibrosis. In contrast, prior human studies using ARBs for HCM have targeted heterogeneous adult cohorts with well-established disease. The VANISH trial is testing the safety and feasibility of disease-modifying therapy with an ARB in genotyped HCM patients with early disease. Methods: A randomized, placebo-controlled, double-blind clinical trial is being conducted in sarcomere mutation carriers, 8 to 45 years old, with HCM and no/minimal symptoms, or those with early phenotypic manifestations but no LVH. Participants are randomly assigned to receive valsartan 80 to 320 mg daily (depending on age and weight) or placebo. The primary endpoint is a composite of 9 z-scores in domains representing myocardial injury/hemodynamic stress, cardiac morphology, and function. Total z-scores reflecting change from baseline to final visits will be compared between treatment groups. Secondary endpoints will assess the impact of treatment on mutation carriers without LVH, and analyze the influence of age, sex, and genotype. Conclusions: The VANISH trial is testing a new strategy of disease modification for treating sarcomere mutation carriers with early HCM, and those at risk for its development. In addition, further insight into disease mechanisms, response to therapy, and phenotypic evolution will be gained

Reduction in Recurrent Cardiovascular Events with Prasugrel Compared with Clopidogrel in Patients with Acute Coronary Syndromes from the TRITON-TIMI 38 Trial

Aims: In the TRITON-TIMI 38 trial, greater platelet inhibition with prasugrel reduced the first occurrence of the primary endpoint (cardiovascular death, MI, or stroke) compared with clopidogrel in patients with an acute coronary syndrome (ACS) undergoing planned percutaneous coronary intervention. We hypothesized that prasugrel would reduce not only first events but also recurrent primary endpoint events and therefore total events compared with clopidogrel. Methods and results: Poisson regression analysis was performed to compare the number of occurrences of the primary endpoint between prasugrel and clopidogrel in TRITON-TIMI 38. Landmark analytic methods were used to evaluate the risk of a recurrent primary endpoint event following an initial non-fatal endpoint event. Among patients with an initial non-fatal event, second events were significantly reduced with prasugrel compared to clopidogrel (10.8 vs. 15.4%, HR 0.65, 95% CI 0.46–0.92; P = 0.016), as was CV death following the non-fatal event (3.7 vs. 7.1%, HR 0.46, 95% CI 0.25–0.82; P = 0.008). Overall there was a reduction of 195 total primary efficacy events with prasugrel vs. clopidogrel (rate ratio 0.79, 95% CI 0.71–0.87; P < 0.001). Recurrent bleeding events occurred infrequently (TIMI major non-CABG bleeds: four with prasugrel and two with clopidogrel). Study drug discontinuation was frequent following the initial major bleeding event (42% of patients discontinued study drug). Conclusion: While standard statistical analytic techniques for clinical trials censor patients who experience a component of the primary composite endpoint, total cardiovascular events remain important to both patients and clinicians. Prasugrel, a more potent anti-platelet agent, reduced both first and subsequent cardiovascular events compared with clopidogrel in patients with ACS

Multiple species comparison of cardiac troponin T and dystrophin: unravelling the DNA behind dilated cardiomyopathy

Animals have frequently been used as models for human disorders and mutations. Following advances in genetic testing and treatment options, and the decreasing cost of these technologies in the clinic, mutations in both companion and commercial animals are now being investigated. A recent review highlighted the genes associated with both human and non-human dilated cardiomyopathy. Cardiac troponin T and dystrophin were observed to be associated with both human and turkey (troponin T) and canine (dystrophin) dilated cardiomyopathies. This review gives an overview of the work carried out in cardiac troponin T and dystrophin to date in both human and animal dilated cardiomyopathy

Effect of saxagliptin on renal outcomes in the SAVOR-TIMI 53 trial.

OBJECTIVE: Dipeptidyl peptidase 4 inhibitors may have a protective effect in diabetic nephropathy. RESEARCH DESIGN AND METHODS: We studied renal outcomes of 16,492 patients with type 2 diabetes, randomized to saxagliptin versus placebo and followed for a median of 2.1 years in the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus Thrombolysis in Myocardial Infarction 53 trial. RESULTS: At baseline: 9,696 (58.8%) subjects had normoalbuminuria (albumin/creatinine ratio [ACR] 300 mg/g). Treatment with saxagliptin was associated with improvement in and/or less deterioration in ACR categories from baseline to end of trial (EOT) (P = 0.021, P 50 mL/min/BSA, -105 mg/g (P = 0.011) for 50 ≥ eGFR ≥ 30 mL/min/BSA, and -245.2 mg/g (P = 0.086) for eGFR 6.0 mg/dL, were similar as well. CONCLUSIONS: Treatment with saxagliptin improved ACR, even in the normoalbuminuric range, without affecting eGFR. The beneficial effect of saxagliptin on albuminuria could not be explained by its effect on glycemic control

Effect of Oral Iron Repletion on Exercise Capacity in Patients With Heart Failure With Reduced Ejection Fraction and Iron Deficiency: The IRONOUT HF Randomized Clinical Trial.

Importance: Iron deficiency is present in approximately 50% of patients with heart failure with reduced left ventricular ejection fraction (HFrEF) and is an independent predictor of reduced functional capacity and mortality. However, the efficacy of inexpensive readily available oral iron supplementation in heart failure is unknown. Objective: To test whether therapy with oral iron improves peak exercise capacity in patients with HFrEF and iron deficiency. Design, Setting, and Participants: Phase 2, double-blind, placebo-controlled randomized clinical trial of patients with HFrEF ( Interventions: Oral iron polysaccharide (n = 111) or placebo (n = 114), 150 mg twice daily for 16 weeks. Main Outcomes and Measures: The primary end point was a change in peak oxygen uptake (V̇o2) from baseline to 16 weeks. Secondary end points were change in 6-minute walk distance, plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, and health status as assessed by Kansas City Cardiomyopathy Questionnaire (KCCQ, range 0-100, higher scores reflect better quality of life). Results: Among 225 randomized participants (median age, 63 years; 36% women) 203 completed the study. The median baseline peak V̇o2 was 1196 mL/min (interquartile range [IQR], 887-1448 mL/min) in the oral iron group and 1167 mL/min (IQR, 887-1449 mL/min) in the placebo group. The primary end point, change in peak V̇o2 at 16 weeks, did not significantly differ between the oral iron and placebo groups (+23 mL/min vs -2 mL/min; difference, 21 mL/min [95% CI, -34 to +76 mL/min]; P = .46). Similarly, at 16 weeks, there were no significant differences between treatment groups in changes in 6-minute walk distance (-13 m; 95% CI, -32 to 6 m), NT-proBNP levels (159; 95% CI, -280 to 599 pg/mL), or KCCQ score (1; 95% CI, -2.4 to 4.4), all P \u3e .05. Conclusions and Relevance: Among participants with HFrEF with iron deficiency, high-dose oral iron did not improve exercise capacity over 16 weeks. These results do not support use of oral iron supplementation in patients with HFrEF. Trial Registration: clinicaltrials.gov Identifier: NCT02188784