Dependent functional status rather than age is a better predictor of adverse outcomes after excision of an infected abdominal aortic graft.

OBJECTIVE: The optimal management of infected abdominal aortic grafts is complete surgical excision plus in situ or extra-anatomic revascularization in patients who can tolerate this morbid operation. In addition to using age and the presence of comorbidities for risk assessment, physicians form a global clinical impression when deciding whether to offer excision or to manage conservatively. Functional status is a distinct objective measure that can inform this decision. This study examines the relative impact of age and functional status on outcomes of infected abdominal aortic graft excision to guide surgical decision-making. METHODS: Current Procedural Terminology code 35907 was used to identify patients undergoing excision of infected abdominal aortic graft in the 2005 to 2017 American College of Surgeons - National Surgical Quality Improvement Program (NSQIP) database. Patients were stratified by the upper age quartile (75 years old) as a cutoff, and then by functional status, independent vs dependent (as defined by NSIQIP). The patients were then stratified into four groups: Younger (<75)/Independent, Younger (<75)/Dependent, Older (≥75)/Independent, and Older (≥75)/Dependent. Outcomes measured included 30-day mortality and major organ-system dysfunction. RESULTS: There were 814 patients who underwent infected abdominal aortic graft excision: 508 patients (62%) were Younger/Independent, 89 patients (11%) were Younger/Dependent, 176 patients (22%) were Older/Independent, and 41 patients (5%) were Older/Dependent. There was no statistically significant difference in 30-day mortality for Younger/Dependent (odds ratio [OR], 1.66; 95% confidence interval [CI], 0.90-3.09; P = .536) or Older/Independent (OR, 1.31; 95% CI, 0.78-2.19; P = .311) patients when compared with Younger/Independent patients, which suggests that neither old age nor dependent functional status by itself adversely affects mortality. However, when both factors were present, Older/Dependent patients had three times higher mortality when compared with Younger/Independent patients (41.5% vs 13.4%, respectively; OR, 3.13; 95% CI, 1.46-6.71; P = .003). Furthermore, as long as patients presented with independent functional status, old age by itself did not adversely affect major organ-system dysfunction (ORs for Older/Independent vs Younger/Independent were 0.76 [P = .454], 1.04 [P = .874], and 0.90 [P = .692] for cardiac, pulmonary, and renal complications, respectively). On the contrary, even in younger patients, dependent functional status was significantly associated with higher pulmonary complications (Younger/Dependent vs Younger/Independent: OR, 2.22; 95% CI, 1.33-3.73; P = .002) and higher rates of unplanned reoperation (OR, 2.67; 95% CI, 1.62-4.41; P < .0001). CONCLUSIONS: Dependent functional status has significant association with adverse outcomes after excision of infected abdominal aortic grafts, whereas old age alone does not. Therefore, this procedure could be considered in appropriately selected elderly patients with otherwise good functional status. However, caution should be applied in dependent patients regardless of age due to the risk of pulmonary complications.

Cationic zinc is required for factor XII recruitment and activation by stimulated platelets and for thrombus formation in vivo.

BACKGROUND: Although divalent zinc (Zn2+ ) is known to bind factor (F)XII and affect its sensitivity to autoactivation, little is known about the role of Zn2+ in the binding of FXII to platelets, where FXII activation is thought to occur in vivo, and the function of Zn2+ during thrombus formation following vascular injury remains poorly understood. OBJECTIVES: To evaluate the role of Zn2+ in platelet-dependent FXIIa generation. METHODS: FXII binding to platelets and FXII activation by stimulated platelets were assessed using flow cytometry and a platelet-dependent thrombin generation assay. The mouse cremaster laser injury model was used to evaluate the impact of Zn2+ chelation on thrombus formation in vivo. RESULTS: Our data demonstrate that stimulated platelets support FXII-dependent thrombin generation and that FXII activation by platelets requires the presence of Zn2+ . By contrast, thrombin generation by stimulated endothelial cells occurred independently of FXII and Zn2+ . Using flow cytometry, we found that FXII-fluorescein-5-isothiocyanate binds to the surfaces of stimulated platelets in a specific and Zn2+ -dependent manner, whereas resting platelets demonstrated minimal binding. Other physiologically-relevant divalent cations are unable to support this interaction. Consistent with these findings, the Zn2+ -specific chelator ethylenediaminetetraacetic acid calcium disodium salt confers thromboprotection in the mouse cremaster laser injury model without causing increased bleeding. We observed an identical phenotype in FXII null mice tested in the same system. CONCLUSIONS: Our results suggest a novel role for Zn2+ in the binding and activation of FXII at the platelet surface, an interaction that appears crucial to FXII-dependent thrombin generation but dispensable for hemostasis.

Tie2 protects the vasculature against thrombus formation in systemic inflammation.

Disordered coagulation contributes to death in sepsis and lacks effective treatments. Existing markers of disseminated intravascular coagulation (DIC) reflect its sequelae rather than its causes, delaying diagnosis and treatment. Here we show that disruption of the endothelial Tie2 axis is a sentinel event in septic DIC. Proteomics in septic DIC patients revealed a network involving inflammation and coagulation with the Tie2 antagonist, angiopoietin-2 (Angpt-2), occupying a central node. Angpt-2 was strongly associated with traditional DIC markers including platelet counts, yet more accurately predicted mortality in 2 large independent cohorts (combined N = 1,077). In endotoxemic mice, reduced Tie2 signaling preceded signs of overt DIC. During this early phase, intravital imaging of microvascular injury revealed excessive fibrin accumulation, a pattern remarkably mimicked by Tie2 deficiency even without inflammation. Conversely, Tie2 activation normalized prothrombotic responses by inhibiting endothelial tissue factor and phosphatidylserine exposure. Critically, Tie2 activation had no adverse effects on bleeding. These results mechanistically implicate Tie2 signaling as a central regulator of microvascular thrombus formation in septic DIC and indicate that circulating markers of the Tie2 axis could facilitate earlier diagnosis. Finally, interventions targeting Tie2 may normalize coagulation in inflammatory states while averting the bleeding risks of current DIC therapies.

PAR1 agonists stimulate APC-like endothelial cytoprotection and confer resistance to thromboinflammatory injury.

Stimulation of protease-activated receptor 1 (PAR1) on endothelium by activated protein C (APC) is protective in several animal models of disease, and APC has been used clinically in severe sepsis and wound healing. Clinical use of APC, however, is limited by its immunogenicity and its anticoagulant activity. We show that a class of small molecules termed "parmodulins" that act at the cytosolic face of PAR1 stimulates APC-like cytoprotective signaling in endothelium. Parmodulins block thrombin generation in response to inflammatory mediators and inhibit platelet accumulation on endothelium cultured under flow. Evaluation of the antithrombotic mechanism showed that parmodulins induce cytoprotective signaling through Gßγ, activating a PI3K/Akt pathway and eliciting a genetic program that includes suppression of NF-κB-mediated transcriptional activation and up-regulation of select cytoprotective transcripts. STC1 is among the up-regulated transcripts, and knockdown of stanniocalin-1 blocks the protective effects of both parmodulins and APC. Induction of this signaling pathway in vivo protects against thromboinflammatory injury in blood vessels. Small-molecule activation of endothelial cytoprotection through PAR1 represents an approach for treatment of thromboinflammatory disease and provides proof-of-principle for the strategy of targeting the cytoplasmic surface of GPCRs to achieve pathway selective signaling.

Developing and Evaluating a Flexible Wireless Microcoil Array Based Integrated Interface for Epidural Cortical Stimulation.

Stroke leads to serious long-term disability. Electrical epidural cortical stimulation has made significant improvements in stroke rehabilitation therapy. We developed a preliminary wireless implantable passive interface, which consists of a stimulating surface electrode, receiving coil, and single flexible passive demodulated circuit printed by flexible printed circuit (FPC) technique and output pulse voltage stimulus by inductively coupling an external circuit. The wireless implantable board was implanted in cats' unilateral epidural space for electrical stimulation of the primary visual cortex (V1) while the evoked responses were recorded on the contralateral V1 using a needle electrode. The wireless implantable board output stable monophasic voltage stimuli. The amplitude of the monophasic voltage output could be adjusted by controlling the voltage of the transmitter circuit within a range of 5-20 V. In acute experiment, cortico-cortical evoked potential (CCEP) response was recorded on the contralateral V1. The amplitude of N2 in CCEP was modulated by adjusting the stimulation intensity of the wireless interface. These results demonstrated that a wireless interface based on a microcoil array can offer a valuable tool for researchers to explore electrical stimulation in research and the dura mater-electrode interface can effectively transmit electrical stimulation.