Duration of triple antithrombotic therapy and clinical outcomes after percutaneous coronary intervention in atrial fibrillation.

BACKGROUND: Triple antithrombotic therapy (TAT) with aspirin, a P2Y12 inhibitor, and oral anticoagulation in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) raises concerns about increased bleeding. Regimens incorporating more potent P2Y12 inhibitors over clopidogrel have not been investigated adequately. RESEARCH DESIGN AND METHODS: A retrospective observational study was performed on 387 patients with AF receiving TAT for 1 month (n = 236) or ≤1 week (n = 151) after PCI. Major and clinically relevant non-major bleeding and major adverse cardiac and cerebrovascular events (MACCE) were assessed up to 30 days post-procedure. RESULTS: Bleeding was less frequent with ≤1 week versus 1 month of TAT (3.3 vs 9.3%; p = 0.025) while MACCE were similar (4.6 vs 4.7%; p = 0.998). No differences in bleeding or MACCE were observed between ticagrelor/prasugrel and clopidogrel regimens. For patients receiving ≤1 week of TAT, no excess of MACCE was seen in the subgroup given no further aspirin post-PCI compared with those given aspirin for up to 1 week (3.6 vs 5.2%). CONCLUSIONS: TAT post-PCI for ≤1 week was associated with less bleeding despite greater use of ticagrelor/prasugrel but similar MACCE versus 1-month TAT. These findings support further studies on safety and efficacy of dual therapy with ticagrelor/prasugrel immediately after PCI.

A therapeutic antibody targeting osteoprotegerin attenuates severe experimental pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a rare but fatal disease. Current treatments increase life expectancy but have limited impact on the progressive pulmonary vascular remodelling that drives PAH. Osteoprotegerin (OPG) is increased within serum and lesions of patients with idiopathic PAH and is a mitogen and migratory stimulus for pulmonary artery smooth muscle cells (PASMCs). Here, we report that the pro-proliferative and migratory phenotype in PASMCs stimulated with OPG is mediated via the Fas receptor and that treatment with a human antibody targeting OPG can attenuate pulmonary vascular remodelling associated with PAH in multiple rodent models of early and late treatment. We also demonstrate that the therapeutic efficacy of the anti-OPG antibody approach in the presence of standard of care vasodilator therapy is mediated by a reduction in pulmonary vascular remodelling. Targeting OPG with a therapeutic antibody is a potential treatment strategy in PAH.

Pulmonary Artery Denervation Attenuates Pulmonary Arterial Remodeling in Dogs With Pulmonary Arterial Hypertension Induced by Dehydrogenized Monocrotaline.

OBJECTIVES: This study aimed to investigate sympathetic nerve (SN) ultrastructural changes and hemodynamic and pulmonary artery (PA) pathological improvements by pulmonary arterial denervation (PADN) in animals with pulmonary arterial hypertension (PAH), as well as the underlying mechanisms. BACKGROUND: SN overactivity plays a role in PAH. Previous studies have reported short-term improvements in pulmonary arterial pressure (PAP) and cardiac function by PADN, but PA remodeling and the associated mechanisms remain unclear. METHODS: Forty dogs were randomly (ratio of 1:3) assigned to the control (intra-atrial injection of N-dimethylacetamide, 3 mg/kg) and test (intra-atrial injection of dehydrogenized-monocrotaline, 3 mg/kg) groups. After 8 weeks, the animals in the test group with a mean PAP >25 mm Hg (n = 20) were randomized (ratio of 1:1) into the sham and PADN groups. At 14 weeks, the hemodynamics, medial wall thickness and PA muscularization, and messenger ribonucleic acid expression of genes in lung tissues were measured. Another 35 PAH dogs were used to measure the SN conduction velocity, electron microscopic assessment, and nerve distribution. RESULTS: PADN induced significant SN demyelination and axon loss and slowed SN conduction velocity over time, with resulting profound reductions in the mean PAP (23.5 ± 2.3 mm Hg vs. 33.7 ± 5.8 mm Hg), pulmonary vessel resistance (3.5 ± 2.3 Wood units vs. 7.7 ± 1.7 Wood units), medial wall thickness (22.3 ± 3.3% vs. 30.4 ± 4.1%), and full muscularization (40.3 ± 9.3% vs. 57.1 ± 5.7%) and increased nonmuscularization (29.8 ± 6.1% vs. 12.9 ± 4.9%) compared with the Sham group (all p < 0.001). PADN inhibited the messenger ribonucleic acid expression of genes correlated with inflammation, proliferation, and vasoconstriction. CONCLUSIONS: PADN induces permanent SN injury and subsequent improvements in hemodynamics and PA remodeling in animals with PAH through mechanisms that may be experimentally and clinically beneficial.

The effect of interleukin-1 receptor antagonist therapy on markers of inflammation in non-ST elevation acute coronary syndromes: the MRC-ILA Heart Study.

AIMS: Acute coronary syndromes (ACSs) are driven by inflammation within coronary plaque. Interleukin-1 (IL-1) has an established role in atherogenesis and the vessel-response to injury. ACS patients have raised serum markers of inflammation. We hypothesized that if IL-1 is a driving influence of inflammation in non-ST elevation ACS (NSTE-ACS), IL-1 inhibition would reduce the inflammatory response at the time of ACS. METHODS AND RESULTS: A phase II, double-blinded, randomized, placebo-controlled, study recruited 182 patients with NSTE-ACS, presenting <48 h from onset of chest pain. Treatment was 1:1 allocation to daily, subcutaneous IL-1receptor antagonist (IL-1ra) or placebo for 14 days. Baseline characteristics were well matched. Treatment compliance was 85% at 7 days. The primary endpoint (area-under-the-curve for C-reactive protein over the first 7 days) was: IL-1ra group, 21.98 mg day/L (95%CI 16.31-29.64); placebo group, 43.5 mg day/L (31.15-60.75) (geometric mean ratio = 0.51 mg/L; 95%CI 0.32-0.79; P = 0.0028). In the IL-1ra group, 14-day achieved high-sensitive C-reactive protein (P < 0.0001) and IL-6 levels (P = 0.02) were lower than Day 1. Sixteen days after discontinuation of treatment (Day 30) high-sensitive C-reactive protein levels had risen again in the IL-1ra group [IL-1ra; 3.50 mg/L (2.65-4.62): placebo; 2.21 mg/L (1.67-2.92), P = 0.022]. MACE at Day 30 and 3 months was similar but at 1 year there was a significant excess of events in the IL-1ra group. CONCLUSION: IL-1 drives C-reactive protein elevation at the time of NSTE-ACS. Following 14 days IL-1ra treatment inflammatory markers were reduced. These results show the importance of IL-1 as a target in ACS, but also indicate the need for additional studies with anti-IL-1 therapy in ACS to assess duration and safety. CLINICAL TRIAL REGISTRATION EUCTR: 2006-001767-31-GB: www.clinicaltrialsregister.eu/ctr-search/trial/2006-001767-31/GB.

Blood flow suppresses vascular Notch signalling via dll4 and is required for angiogenesis in response to hypoxic signalling.

AIMS: The contribution of blood flow to angiogenesis is incompletely understood. We examined the effect of blood flow on Notch signalling in the vasculature of zebrafish embryos, and whether blood flow regulates angiogenesis in zebrafish with constitutively up-regulated hypoxic signalling. METHODS AND RESULTS: Developing zebrafish (Danio rerio) embryos survive via diffusion in the absence of circulation induced by knockdown of cardiac troponin T2 or chemical cardiac cessation. The absence of blood flow increased vascular Notch signalling in 48 h post-fertilization old embryos via up-regulation of the Notch ligand dll4. Despite this, patterning of the intersegmental vessels is not affected by absent blood flow. We therefore examined homozygous vhl mutant zebrafish that have constitutively up-regulated hypoxic signalling. These display excessive and aberrant angiogenesis from 72 h post-fertilization, with significantly increased endothelial number, vessel diameter, and length. The absence of blood flow abolished these effects, though normal vessel patterning was preserved. CONCLUSION: We show that blood flow suppresses vascular Notch signalling via down-regulation of dll4. We have also shown that blood flow is required for angiogenesis in response to hypoxic signalling but is not required for normal vessel patterning. These data indicate important differences in hypoxia-driven vs. developmental angiogenesis.