Impact of polyvascular disease on patients with atrial fibrillation: Insights from ROCKET AF.

BACKGROUND: We investigated the impact of polyvascular disease in patients enrolled in ROCKET AF. METHODS: Cox regression models were used to assess clinical outcomes and treatment effects of rivaroxaban compared with warfarin in patients with atrial fibrillation and coronary, peripheral, or carotid artery disease, or any combination of the 3. RESULTS: A total of 655 (4.6%) patients had polyvascular disease (≥2 disease locations), and 3,391 (23.8%) had single-arterial bed disease. Patients with polyvascular disease had similar rates of stroke/systemic embolism but higher rates of cardiovascular and bleeding events when compared with those without vascular disease. Use of rivaroxaban compared with warfarin was associated with higher rates of stroke in patients with polyvascular disease (hazard ratio [HR] 2.41, 95% CI 1.05-5.54); however, this was not seen in patients with single-bed (HR 0.90, 95% CI 0.64-1.28) or no vascular disease (HR 0.85, 95% CI 0.69-1.04; interaction P = .058). There was a significant interaction for major or nonmajor clinically relevant bleeding in patients with polyvascular (HR 1.23, 95% CI 0.91-1.65) and single-bed vascular disease (HR 1.30, 95% CI 1.13-1.49) treated with rivaroxaban compared with warfarin when compared with those without vascular disease (HR 0.95, 95% CI 0.87-1.04; interaction P = .0006). Additional antiplatelet therapy in this population did not improve stroke or cardiovascular outcomes. CONCLUSION: The use of rivaroxaban compared with warfarin was associated with a higher risk of stroke and bleeding in patients with polyvascular disease enrolled in ROCKET AF. Further studies are needed to understand the optimal management of this high-risk population.

Clinical and metabolomic risk factors associated with rapid renal function decline in sickle cell disease.

Sickle cell disease (SCD) nephropathy and lower estimated glomerular filtration rate (eGFR) are risk factors for early mortality. Furthermore, rate of eGFR decline predicts progression to end-stage renal disease in many clinical settings. However, factors predicting renal function decline in SCD are poorly documented. Using clinical, laboratory, genetic, and metabolomic data, we evaluated predictors of renal function decline in a longitudinal cohort of 288 adults (mean age 33.0 years). In 193 subjects with 5-year follow-up data, mean rate of eGFR decline was 2.35 mL/min/1.73 m2 /year, nearly twice that of African American adults overall. Hyperfiltration was prevalent at baseline (61.1%), and 36.8% of subjects experienced rapid eGFR decline (≥3 mL/min/1.73 m2 /year). Severe Hb genotype; proteinuria; higher platelet and reticulocyte counts, and systolic BP; and lower Hb level and BMI were associated with rapid decline. A risk scoring system was created using these 7 variables and was highly predictive of rapid eGFR decline, with odds of rapid decline increasing 1.635-fold for every point increment (P < 0.0001). Rapid eGFR decline was also associated with higher organ system severity score and peak creatinine. Additionally, two metabolites (asymmetric dimethylarginine and quinolinic acid) were associated with rapid decline. Further investigation into longitudinal SCD nephropathy (SCDN) trajectory, early markers of SCDN, and tools for risk stratification should inform interventional studies targeted to slowing GFR decline and improving SCD outcomes.

Endothelial specific SIRT3 deletion impairs glycolysis and angiogenesis and causes diastolic dysfunction.

Endothelial glycolysis plays a critical role in the regulation of angiogenesis. We investigated the role of Sirtuin 3 (SIRT3) on endothelial cell (EC) glycolytic metabolism, angiogenesis, and diastolic function. Our aim was to test the hypothesis that loss of SIRT3 in ECs impairs endothelial glycolytic metabolism and angiogenesis and contributes to myocardial capillary rarefaction and the development of diastolic dysfunction. Using SIRT3 deficient ECs, SIRT3 was found to regulate a metabolic switch between mitochondrial respiration and glycolysis. SIRT3 knockout (KO)-ECs exhibited higher mitochondrial respiration and reactive oxygen species (ROS) formation. SIRT3 knockout (KO)-ECs exhibited a reduction in the expression of glycolytic enzyme, PFKFB3, and a fall in glycolysis and angiogenesis. Blockade of PFKFB3 reduced glycolysis and downregulated expression of VEGF and Angiopoietin-1 (Ang-1) in ECs. Deletion of SIRT3 in ECs also impaired hypoxia-induced expression of HIF-2α, VEGF, and Ang-1, as well as reduced angiogenesis. In vivo, endothelial-specific SIRT3 KO (ECKO) mice exhibited a myocardial capillary rarefaction together with a reduced coronary flow reserve (CFR) and diastolic dysfunction. Histologic study further demonstrated that knockout of SIRT3 in ECs significantly increased perivascular fibrosis in the coronary artery. These results implicate a role of SIRT3 in modulating endothelial function and cardiac function. Ablation of SIRT3 leads to impairment of EC glycolytic metabolism and angiogenic signaling, which may contribute to coronary microvascular rarefaction and diastolic dysfunction in SIRT3 ECKO mice.

Ablation of endothelial prolyl hydroxylase domain protein-2 promotes renal vascular remodelling and fibrosis in mice.

Accumulating evidence demonstrates that hypoxia-inducible factor (HIF-α) hydroxylase system has a critical role in vascular remodelling. Using an endothelial-specific prolyl hydroxylase domain protein-2 (PHD2) knockout (PHD2EC KO) mouse model, this study investigates the regulatory role of endothelial HIF-α hydroxylase system in the development of renal fibrosis. Knockout of PHD2 in EC up-regulated the expression of HIF-1α and HIF-2α, resulting in a significant decline of renal function as evidenced by elevated levels of serum creatinine. Deletion of PHD2 increased the expression of Notch3 and transforming growth factor (TGF-ß1) in EC, thus further causing glomerular arteriolar remodelling with an increased pericyte and pericyte coverage. This was accompanied by a significant elevation of renal resistive index (RI). Moreover, knockout of PHD2 in EC up-regulated the expression of fibroblast-specific protein-1 (FSP-1) and increased interstitial fibrosis in the kidney. These alterations were strongly associated with up-regulation of Notch3 and TGF-ß1. We concluded that the expression of PHD2 in endothelial cells plays a critical role in renal fibrosis and vascular remodelling in adult mice. Furthermore, these changes were strongly associated with up-regulation of Notch3/TGF-ß1 signalling and excessive pericyte coverage.

Efficacy and safety of rivaroxaban vs. warfarin in patients with non-valvular atrial fibrillation and a history of cancer: observations from ROCKET AF.

AIMS: The management of anticoagulation therapy in patients with atrial fibrillation (AF) and cancer is challenging due to increased thrombotic and bleeding risks. We sought to determine the safety and efficacy of rivaroxaban in patients with AF and a history of cancer. METHODS AND RESULTS: ROCKET AF randomized 14 264 patients with AF to rivaroxaban or warfarin with a median follow-up of 1.9 years. Cox regression models were used to assess the association between cancer history and clinical outcomes, and the relative treatment effect of rivaroxaban vs. warfarin in these patients. A total of 640 patients enrolled in ROCKET AF had a history of cancer, with the most common types being prostate (28.6%), colorectal (16.1%), and breast (14.7%) cancer. Patients with a history of cancer were older, more frequently male, more likely to have prior vitamin K antagonist (VKA) use and had higher rates of overall bleeding [hazard ratio (HR) 1.30, 95% confidence interval (CI) 1.16-1.47; P < 0.0001] and non-cardiovascular death (HR 1.47, 95% CI 1.04-2.07; P = 0.031) compared with those with no cancer history. There were no significant associations between cancer history and stroke, venous thromboembolism, or myocardial infarction. The relative efficacy of rivaroxaban vs. warfarin for prevention of stroke/systemic embolism was similar in those with and without a history of cancer (interaction P-value = 0.21). CONCLUSION: In ROCKET AF, a history of cancer was associated with a higher risk of bleeding and non-cardiovascular death, but not ischaemic events. The relative efficacy and safety of rivaroxaban compared with warfarin were not significantly different in patients with and without a history of cancer. The results of this study are exploratory and should be taken in context of the study population, which may not be generalizable to those with advanced malignancy. Further investigation is needed to understand optimal anticoagulation strategies in patients with AF and cancer.Clinical trial registration: ClinicalTrials.gov: NCT00403767.

Comparison of Anticoagulant Therapy for Atrial Fibrillation - Novel Oral Anticoagulants Versus Vitamin K Antagonists.

In patients with non-valvular atrial fibrillation (NVAF), oral anticoagulation is important for prevention of stroke and systemic embolism (SE). While Vitamin K antagonists (VKAs) have historically been the standard of care, these medications are limited by numerous food and drug interactions with onerous requirements for frequent monitoring and dose adjustments. Over the past decade, several novel oral anticoagulants (NOACs) have been developed to directly inhibit factor IIa/thrombin (dabigatran) or activated factor X (apixaban, rivaroxaban, edoxaban). These medications have been shown to be at least as effective as warfarin for stroke prevention in NVAF with more favorable safety profiles. However, their advantages are underscored by a lack of specific antidotes and assays quantifying their anticoagulant effects. This paper addresses the use of NOACs compared to VKAs in patients with NVAF, with a special focus on high-risk populations, including the elderly, those with renal disease, diabetes mellitus, coronary artery disease, and previous stroke. The current literature surrounding special clinical scenarios including the treatment of bleeding, perioperative management, and the use of NOACs in cardioversion and catheter ablation will be also discussed.

Notch3 deficiency impairs coronary microvascular maturation and reduces cardiac recovery after myocardial ischemia.

RATIONALE: Vascular maturation plays an important role in wound repair post-myocardial infarction (MI). The Notch3 is critical for pericyte recruitment and vascular maturation during embryonic development. OBJECTIVE: This study is to test whether Notch3 deficiency impairs vascular maturation and blunts cardiac functional recovery post-MI. APPROACH AND RESULTS: Wild type (WT) and Notch3 knockout (Notch3KO) mice were subjected to MI by the ligation of left anterior descending coronary artery (LAD). Cardiac function and coronary blood flow reserve (CFR) were measured by echocardiography. The expression of angiogenic growth factor, pericyte/capillary coverage and arteriolar formation were analyzed. Loss of Notch3 in mice resulted in a significant reduction of pericytes and small arterioles. Notch3 KO mice had impaired pericyte/capillary coverage and CFR compared to WT mice. Notch3 KO mice were more prone to ischemic injury with larger infarcted size and higher rates of mortality. The expression of CXCR-4 and VEGF/Ang-1 was significantly decreased in Notch3 KO mice. Notch3 KO mice also had few NG2+/Sca1+ and NG2+/c-kit+ progenitor cells in the ischemic area and exhibited worse cardiac function recovery at 2weeks after MI. These were accompanied by a significant reduction of pericyte/capillary coverage and arteriolar maturation. Furthermore, Notch3 KO mice subjected to MI had increased intracellular adhesion molecule-2 (ICAM-2) expression and CD11b+ macrophage infiltration into ischemic areas compared to that of WT mice. CONCLUSION: Notch3 mutation impairs recovery of cardiac function post-MI by the mechanisms involving the pre-existing coronary microvascular dysfunction conditions, and impairment of pericyte/progenitor cell recruitment and microvascular maturation.

Outcome of Patients Receiving Thrombolytic Therapy While on Rivaroxaban for Nonvalvular Atrial Fibrillation (from Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation).

The safety of intravenous thrombolysis in patients taking rivaroxaban has not been well established. We retrospectively analyzed the outcomes of all patients who received thrombolytic therapy in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF). A review of medical and adverse event records for patients receiving thrombolytic therapy while enrolled in ROCKET AF was performed to determine their baseline characteristics, indications for thrombolysis, and type of agent used. Safety end points were 30-day post-thrombolytic rates of stroke, bleeding, and mortality. A total of 28 patients in ROCKET AF received thrombolytic therapy, with 19 patients on rivaroxaban and 9 patients on warfarin. Ischemic stroke was the most common indication for thrombolysis (n = 10), and alteplase was the most commonly used fibrinolytic agent (n = 14). Of the 19 patients in the rivaroxaban group, there were 2 nonfatal bleeding events and 2 deaths, mostly occurring when thrombolytic therapy was administered within 48 hours of the last rivaroxaban dose. Of the 9 patients in the warfarin group, there was 1 nonfatal bleeding event and 3 deaths, most occurring when thrombolytic therapy was administered outside of 48 hours from the last warfarin dose. In conclusion, these observations suggest that careful assessment of the time since the last dose may be of clinical significance in patients on novel oral anticoagulants who require emergent thrombolysis.