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Unfractionated heparin (UFH) has been the primary anticoagulant of choice on extracorporeal membrane oxygenation (ECMO). However, it is debatable whether bivalirudin (BIV), a direct thrombin inhibitor, may be considered a better alternative anticoagulant option.We searched Embase, Pubmed, Cochrane library, Clinicaltrials.gov, CNKI and Wanfang databases up to 15 June 2021. Randomized controlled trials and observational studies were considered eligible for inclusion. Random-effects meta-analyses, including subgroup analyses, were conducted.A total of 9 studies containing 994 patients were enrolled. All articles were retrospective cohort studies. Compared with UFH, BIV was associated with lower risks of major bleeding (risk ratio [RR]: 0.32, 95% confidence interval [CI] 0.22-0.49), ECMO in-circuit thrombosis (RR: 0.57, 95% CI 0.43-0.74), stroke (RR: 0.52, 95% CI 0.29-0.95) and in-hospital mortality (RR: 0.82, 95% CI 0.69-0.99), and higher rates of survival to ECMO decannulation (RR: 1.18, 95% CI 1.03-1.34). Pooled risk estimates did not show a significant association with clinical thrombotic events (RR: 0.69, 95% CI 0.45-1.07). Moreover, BIV was associated with a lower risk of ECMO in-circuit thrombosis and in-hospital mortality in the adult subgroup but not in the paediatric subgroup. However, leave-one-out sensitivity analyses indicated that the results of stroke, survival to ECMO decannulation and in-hospital mortality should be interpreted with caution.BIV appears to be a potential alternative to UFH in paediatric and adult patients requiring ECMO.

Objectives : The COVID-19 pandemic has been associated with cases of refractory acute respiratory distress syndrome (ARDS) sometimes requiring support with extracorporeal membrane oxygenation (ECMO). Bivalirudin can be used for anticoagulation in patients on ECMO support, but its efficacy and safety in patients with COVID-19 is unknown. We set out to compare the pharmacologic characteristics and dosing requirements of bivalirudin in patients requiring ECMO support for ARDS due to COVID-19 versus ARDS from other etiologies. Design and Setting : This retrospective case control study was performed at Indiana University Health Methodist Hospital in Indianapolis, IN. Participants : Patients were included if they were on veno-venous (VV) ECMO support between June 2019 and June 2020 and divided into two groups: ARDS secondary to COVID-19 and those with ARDS from another etiology (Non-COVID). Interventions : Patient demographics such as age, sex, weight, chronic comorbid conditions, baseline antiplatelet and anticoagulant use, antiplatelet use during ECMO, and need for renal replacement therapy were collected and compared between groups. Time to activated partial thromboplastin time (aPTT) goal, percentage of time at aPTT goal, bivalirudin rates, total bivalirudin requirements, total duration on bivalirudin, total duration on ECMO, mortality, and complications associated with ECMO were collected and compared between groups. Measurements and Main Results : A total of forty-two patients met inclusion criteria (n = 19 COVID-19, n = 23 Non-COVID). However, percentage of aPTTs at goal were maintained more consistently in patients with COVID-19 versus non-COVID (86% vs. 74%: p < 0.01). Higher median (IQR) daily rates (3.1 mCg/kg/min (2.3-5.2) vs. 2.4 mCg/kg/min (1.7-3.3): p = 0.05) and higher median (IQR) maximum rates of bivalirudin (5 mCg/kg/min (3.7-7.5) vs. 3.8 mCg/kg/min (2.5-5): p = 0.03) were required in the COVID-19 group versus the non-COVID group. Time to goal aPTT was similar between groups. There was no difference in complications associated with anticoagulation as demonstrated by similar rates of bleeding and thrombosis between both groups. Conclusions : Patients on ECMO with ARDS from COVID-19 require more bivalirudin overall and higher rates of bivalirudin to maintain goal aPTTs compared to patients without COVID-19. However, COVID-19 patients more consistently maintain goal aPTT. Future randomized trials are needed to support efficacy and safety of bivalirudin for anticoagulation of COVID-19 patients on ECMO.

To assess the effectiveness and safety of bivalirudin compared with heparin monotherapy in elderly patients undergoing percutaneous coronary intervention (PCI).Bivalirudin is recommended for periprocedural use in patients undergoing PCI who are of high bleeding risk. However, its safe and efficacious use in elderly patients, a typical high bleeding risk cohort, in real world practice is yet to be reported.In this single center, real-world observational study, 4736 consecutive elderly patients who underwent PCI were enrolled. Of these, 1240 were treated with bivalirudin and 3496 with heparin according to the periprocedural anticoagulation strategies of PCI. The primary outcome was 12-month net adverse clinical events (NACE) defined as a composite of cardiac death, myocardial infarction, stroke, revascularization, or any bleeding. Propensity score matching (PSM) was used to balance baseline characteristics between groups.After PSM, bivalirudin was found to be associated with lower rates of NACE (19.1% vs. 24.7%, p = 0.002), cardiac death (2.7% vs. 4.3%, p = 0.038), and any bleeding (10.0% vs. 12.9%, p = 0.023) compared to heparin monotherapy. No differences were found in the incidences of myocardial infarction, stroke, revascularization, stent thrombosis (0.1% vs. 0.1%, p = 1.000), and major bleedings (0.5% vs. 0.5%, p = 1.000) between the two patient groups.In this real-world observational study, periprocedural use of bivalirudin in elderly patients who underwent PCI was associated with less cardiac death and any bleeding compared to heparin monotherapy, without increased risk of stent thrombosis.

Tyrosine-O-sulfation is a common post-translational modification (PTM) of proteins following the cellular secretory pathway. First described in human fibrinogen, tyrosine-O-sulfation has long been associated with the modulation of protein–protein interactions in several physiological processes. A number of relevant interactions for hemostasis are largely dictated by this PTM, many of which involving the serine proteinase thrombin (FIIa), a central player in the blood-clotting cascade. Tyrosine sulfation is not limited to endogenous FIIa ligands and has also been found in hirudin, a well-known and potent thrombin inhibitor from the medicinal leech, Hirudo medicinalis. The discovery of hirudin led to successful clinical application of analogs of leech-inspired molecules, but also unveiled several other natural thrombin-directed anticoagulant molecules, many of which undergo tyrosine-O-sulfation. The presence of this PTM has been shown to enhance the anticoagulant properties of these peptides from a range of blood-feeding organisms, including ticks, mosquitos and flies. Interestingly, some of these molecules display mechanisms of action that mimic those of thrombin's bona fide substrates.

Despite their limitations, unfractionated heparin (UFH) and bivalirudin remain standard-of-care parenteral anticoagulants for percutaneous coronary intervention (PCI). We discovered novel direct thrombin inhibitors (DTIs) from tick salivary transcriptomes and optimised their pharmacologic activity. The most potent, ultravariegin, inhibits thrombin with a Ki of 4.0 pM, 445-fold better than bivalirudin. Unexpectedly, despite their greater antithrombotic effect, variegin/ultravariegin demonstrated less bleeding, achieving a 3-to-7-fold wider therapeutic index in rodent thrombosis and bleeding models. When used in combination with aspirin and ticagrelor in a porcine model, variegin/ultravariegin reduced stent thrombosis compared with antiplatelet therapy alone but achieved a 5-to-7-fold lower bleeding time than UFH/bivalirudin. Moreover, two antibodies screened from a naïve human antibody library effectively reversed the anticoagulant activity of ultravariegin, demonstrating proof-of-principle for antidote reversal. Variegin and ultravariegin are promising translational candidates for next-generation DTIs that may reduce peri-PCI bleeding in the presence of antiplatelet therapy., Bleeding complications limits the use of effective antithrombotics therapeutics. Here, the authors developed next-generation direct thrombin inhibitors with low bleeding risks as safe peri-percutaneous coronary intervention anticoagulants when used in combination with antiplatelets.

The incidence rate of cardiovascular diseases is increasing year by year. The demand for coronary artery bypass grafting has been very large. Acellular blood vessels have potential clinical application because of their natural vascular basis, but their biocompatibility and anticoagulant energy need to be improved. We decellularized the abdominal aorta of SD rats, and then modified with bivalirudin via polydopamine. The mechanical properties, blood compatibility, cytocompatibility, immune response, and anticoagulant properties were evaluated, and then the bivalirudin-modified acellular blood vessels were implanted into rats for remodeling evaluation in vivo. The results we got show that the bivalirudin-modified acellular blood vessels showed good cytocompatibility and blood compatibility, and its anti-inflammatory trend was dominant in the immune response. After 3 months of transplantation, the bivalirudin-modified acellular blood vessels did not easily form thrombus. It was not easy to form calcification and could make the host cells grow better. Through vascular stimulation and immunofluorescence test, we found that vascular smooth muscle cells and endothelial cells proliferated well in the bivalirudin group. Bivalirudin-modified acellular blood vessels provided new idea for small diameter tissue engineering blood vessels, and may become a potential clinical substitute for small-diameter vascular grafts.

Background Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse reaction to heparin. Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are routinely anticoagulated with heparin before the initiation of bypass. Heparin is contraindicated, however, in patients with acute HIT, and alternatives to routine practice are often used. While guidelines have recently been published addressing this topic 10, there remains variance between institutions in how these cases are treated. Our goal was to better delineate practice trends in the diagnosis and management of HIT patients requiring CPB. Methods We surveyed members of the Society of Cardiovascular Anesthesiologists (SCA) and the American Society for Extracorporeal Technology (AmSECT) using an online survey tool. Results We received 304 completed surveys (5.8% response rate), 75% completed by an anesthesiologist, and 24% by a perfusionist. The majority of respondents used clinical history and/or antibody testing (71% and 63%, respectively) to diagnose HIT. Seventy-five percent of respondents reported using an institutional protocol for HIT-CPB cases. Most respondents (89%) reported having at least 1 case in the last 3 years, with a total case experience of at least 785 cases (785 = the minimum number of cases in each case volume category × the number of respondents choosing that category). The strategy recommended in published guidelines, bivalirudin, was the most commonly reported alternative anticoagulation strategy (75%) used by respondents in HIT cases, with most (83%) using the activated clotting time (ACT) to monitor anticoagulation. Conclusions Most responding SCA and AmSECT members reported that their institution used a protocol or guideline for HIT/CPB cases, and most guidelines directed the use of bivalirudin as an alternative anticoagulant. Various other methods such as plasmapheresis are also being used with success in this patient population. Further research, including comparison studies of alternative anticoagulant strategies, is required to elucidate the best approach to these difficult cases.

Background: Patients with diabetes mellitus (DM) are considered to increase the risk of thrombosis and bleeding. However, whether DM is an independent risk factor for events in patients anticoagulated with bivalirudin during elective percutaneous coronary intervention (PCI) is not clear. Methods: Patients anticoagulated with bivalirudin during elective PCI from January 2017 to August 2018 in 3 centers were enrolled. The primary endpoint of thrombotic events was major adverse cardiac and cerebrovascular events (MACCE, including all-cause death, myocardial infarction, ischemic revascularization, stent thrombosis, and stroke); the primary endpoint of bleeding events was Bleeding Academic Research Consortium (BARC) 2, 3 or 5 bleeding. Results: 1152 patients were finally enrolled. After one-year follow-up, 89 (7.7%) MACCE and 21 (1.8%) BARC 2, 3 or 5 bleeding occurred. Multivariate Cox regression analysis showed DM was not an independent risk factor for MACCE (hazard ratio [HR]: 1.029, 95% confidence interval [CI]: 0.674-1.573, P = .893), but peripheral artery disease (PAD) history (HR: 2.200, 95%CI: 1.290-3.751, P = .004) was an independent risk factor for MACCE. DM was not an independent risk factor for BARC 2, 3 or 5 bleeding (HR: 0.732, 95%CI: 0.293-1.831, P = .505), but PAD history (HR: 3.029, 95%CI: 1.102-8.332, P = .032) and low hemoglobin level (HR = 0.972, 95%CI: 0.947-0.998, P = .036) were independent risk factors for BARC 2, 3 or 5 bleeding. Conclusions: DM was not an independent risk factor for one-year thrombotic and bleeding events in patients anticoagulated with bivalirudin during elective PCI. More attention should be paid to PAD history and hemoglobin level to identify high-risk patients.

Haematophagous leeches expresses a broad variety of secretory proteins in their salivary glands, among them hirudins and hirudin-like factors. Here we describe the identification, molecular and initial functional characterization of Tandem-Hirudin (TH), a novel salivary gland derived factor identified in the Asian medicinal leech, Hirudinaria manillensis. In contrast to the typical structure of hirudins, TH comprises two globular domains arranged in a tandem-like orientation and lacks the elongated C-terminal tail. Similar structures of thrombin inhibitors have so far been identified only in kissing bugs and ticks. Expression of TH was performed in both cell-based and cell-free bacterial systems. A subsequent functional characterization revealed no evidence for a thrombin-inhibitory potency of TH.

OBJECTIVE: To explore the mechanism of hirudin in the treatment of diabetic kidney disease (DKD). METHODS: Cytoscape software was used to analyze the network between hirudin targets and active components in the treatment of DKD. The biological function and mechanism of effective targets of hirudin for DKD treatment were analyzed by the Database for Annotation, Visualization and Integrated Discovery (DAVID) database. Molecular docking technology was used to simulate the docking of key targets, and the DKD rat model was used to verify the first 4 key targets with high "Hydrogen number" among the top 10 targets verified by molecular docking. RESULTS: Total of 12334 DKD targets were screened in GeneCards, OMIM and other databases, Hirudin and DKD had 247 common target genes, and the protein interaction network got 2115 edges. The DAVID database was used for the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, confirming that hirudin in treatment of DKD involves multiple signaling pathways such as the forkhead box O signaling pathway, the phosphatidylinositol 3-kinase-protein kinase B signaling pathway, the vascular endothelial-derived growth factor signaling pathway and other signaling pathways. The top ten key targets of hirudin in treatment of DKD were verified by molecular docking. Animal experiments showed that hirudin could decrease the expression of caspase-3 in renal tissue of DKD rats, and increase the expression of RAC-alpha serine/threonine-protein kinase, Catalase, and Heat shock protein HSP 90-alpha in renal tissue of DKD rats. CONCLUSION: This study preliminarily reveals that hirudin treats DKD through multiple targets and pathways, and molecular docking and animal experiments indicates the feasibility of this study. Hirudin may be directly or indirectly involved in the regulation of cell metabolism, oxidative stress and other mechanisms in the treatment of DKD, which will lay the foundation for future molecular biological experiments of hirudin in the treatment of DKD.

Chronic kidney disease (CKD) is identified as a widespread chronic progressive disease jeopardizing public health which characterized by gradually loss of renal function. However, there is no efficient therapy to prevail over this disease. Our study was attempting to reveal hirudin's regulation to renal fibrosis as well as the molecular mechanism. We built renal fibrosis models on both cell and animal levels, which were subsequently given with hirudin disposal; then, we performed the transwell assay to estimate the cells' migration and had our detection to relevant proteins with western blot and immunofluorescence. Finally, we commenced both the identification and the determination to the hirudin targeted proteins and its downstream signaling pathways with the methods of network pharmacology. And the results turned out that when it was compared with the model group, the group with hirudin addition came with the suppression in the migration of renal tubular epithelial cells NRK-52E and with a conspicuous decline in the expressions of fibronectin, N-cadherin, vimentin, TGF

Purpose Bivalirudin as a thrombin inhibitor is proven to have a low risk of bleeding during percutaneous coronary intervention (PCI). Some evidence indicates comparable effectiveness and safety between bivalirudin and unfractionated heparin (UFH). Although bivalirudin during PCI offers more clinical and safety benefits to patients with chronic total occlusion (CTO), mostly via radial access, this has not been confirmed. The objective of this study was to examine the efficacy and safety of bivalirudin during percutaneous coronary intervention (PCI) in patients with CTO. Methods This trial used a retrospective cohort study design. Medical information from 736 patients with CTO who underwent PCI with bivalirudin or UFH at the First Affiliated Hospital of Zhengzhou University from July 2019 to September 2020 was extracted and analyzed. The primary end point was the 30-day incidence of net adverse clinical events (NACEs), and the secondary end point was the major adverse cardiovascular events (MACEs), which were related to safety and efficacy, respectively. Other end points incorporated each component of the primary outcome, target vessel revascularization, and stent thrombosis. Clinical and procedural characteristics at baseline were adjusted by using a logistic regression model. Findings Overall, 71.5% of patients with CTO used the radial approach. Both groups exhibited nonsignificant differences in the majority of baseline characteristics. The bivalirudin group was associated with a significant reduction in NACEs (12.9% vs 21.5%; P = 0.002) and major bleeding (2.5% vs 8.0%; P = 0.001) versus the UFH group at the end of the 30-day follow-up. The incidence of MACEs, myocardial infarction, death, stroke, stent thrombosis, and target vessel revascularization did not differ significantly between the 2 groups. Moreover, the bivalirudin group also reported a lower incidence of NACEs in the prespecified subgroups. Implications Bivalirudin exhibited comparative efficacy but superior safety compared with UFH among patients with CTO undergoing PCI. Chinese Clinical Trial Registry: ChiCTR2000034771.

In the present study, bifunctional fusion proteins were designed by fusing the kringle 2 and protease domains of tissue-type plasminogen activator (tPA) to the C-terminal fragment of hirudin. The thrombolytic and anticoagulant activities of these recombinant proteins from mammalian cells were investigated using in vitro coagulation models and chromogenic assays. The results showed that all assayed tPA mutants retained catalytic activity. The C-terminal fragment of hirudin may have weak affinity to thrombin and thus was insufficient to suppress thrombin-mediated fibrin agglutination. The strength of the thrombolytic activity only relied on the selected tPA sequences, and the fibrinolytic efficiency of single-chain protein significantly decreased. Our data indicate that truncated tPA combined with a hirudin peptide may provide a framework for the further development of a new antithrombotic agent.

Aim A typical adult based bivalirudin regimen during cardiopulmonary bypass uses a loading dose of 1 mg.kg-1 and a circuit prime (volume L x 13 mg) with a subsequent intravenous infusion 2.5 mg.h-1 .kg-1 . Dose in children remains unknown. We wished to determine a practical bivalirudin dosing schedule for children undergoing surgery with cardiopulmonary bypass METHODS: Published pharmacokinetic parameters in children who were anticoagulated for cardiac catheterisation using bivalirudin were compared to adult by scaling for size using allometry. An infusion regimen suitable for children was determined using a bivalirudin target concentration (13 mg.L-1 ) common in adults for effect during cardiopulmonary bypass. Predicted bivalirudin infusion rates in children were compared to regimens published as case reports. Results Current pediatric bivalirudin infusion rates are based on those used in adults with titration during cardiopulmonary bypass to achieve activated clotting times longer than 400 s. Bivalirudin clearance (mL.min-1 .kg-1 ) can be estimated in children by scaling adult parameters using allometry. Clearance decreases through childhood and higher infusion rates in children would achieve target concentration rapidly without the need to titrate initial infusion rate. An infusion rate of 4.5 mg.h-1 .kg-1 in a 10 kg infant, 4 mg.h-1 .kg-1 in a 20 kg child and 3.5 mg.h-1 .kg-1 in a child 30-40 kg will target an activated clotting time slower than 400 s. Adult regimens could be used in those children heavier than 50 kg. Conclusion Bivalirudin infusion in children should be started after loading dose at rates greater than those used in adults. Dose in neonates remains uncertain because neither pharmacokinetics nor coagulation pharmacodynamics have been adequately characterized.

Background: To investigate the efficacy and safety of hirudin plus aspirin therapy compared with warfarin in the secondary prevention of cardioembolic stroke due to nonvalvular atrial fibrillation (NVAF). Methods: Patients with cardioembolic stroke due to NVAF were prospectively enrolled from 18 collaborating hospitals from Dec 2011 to June 2015. Fourteen days after stroke onset, eligible patients were assigned to the hirudin plus aspirin group (natural hirudin prescribed as the traditional Chinese medicine Maixuekang capsule, 0.75 g, three times daily, combined with aspirin 100 mg, once daily) or the warfarin group (dose-adjusted warfarin targeting international normalized ratio (INR) 2-3, with an initial daily dose of 1.25 mg). Patients were followed up at 1, 2, 3, 6, 9, and 12 months after stroke onset. Time in therapeutic range (TTR) was calculated according to Rosendaal methodology to evaluate the quality of INR management in the warfarin group. The primary efficacy endpoint was the recurrence of stroke within 12 months after stroke onset. Safety was assessed as the occurrence of the composite event “intracranial hemorrhage and other bleeding events, death, and other serious adverse events”. The Cox proportional hazard model and Kaplan-Meier curve were used to analyze the efficacy and safety events. Results: A total of 221 patients entered final analysis with 112 patients in the hirudin plus aspirin group and 109 in the warfarin group. Over the whole duration of our study, TTR for patients taking warfarin was 66.5 % ± 21.5%. A significant difference was not observed in the recurrence of stroke between the two groups (3.57% vs. 2.75%; P = 0.728). The occurrence of safety events was significantly lower in the hirudin plus aspirin group (2.68% vs.10.09%; P = 0.024). The risk for efficacy event was similar between the two groups (hazard ratio (HR), 1.30; 95% confidence interval (CI), 0.29-5.80). The safety risk was significantly lower in the hirudin plus aspirin group (HR, 0.27; 95% CI, 0.07-0.95). Kaplan-Meier analysis revealed significant difference in the temporal distribution in safety events (P = 0.023) but not in stroke recurrence (P = 0.726). Conclusion: Significant difference in efficacy was not detected between warfarin group and hirudin plus aspirin group. Compared with warfarin, hirudin plus aspirin therapy had lower safety risk in the secondary prevention of cardioembolic stroke due to NVAF.

To conveniently and effectively cure heart valve diseases or defects, combined with transcatheter valve technology, bioprosthetic heart valves (BHVs) originated from the decellularized porcine pericardium (D-PP) have been broadly used in clinics. Unfortunately, most clinically available BHVs crosslinked with glutaraldehyde (GA) were challenged in their long-term tolerance, degenerative structural changes, and even failure, owing to the synergistic impact of multitudinous elements (cytotoxicity, calcification, immune responses, etc.). In this work, dialdehyde pectin (AP) was prepared by oxidizing the o-dihydroxy of pectin with sodium periodate. Hereafter, the AP-fixed PP model was obtained by crosslinking D-PP with AP with high aldehyde content (6.85 mmol g-1), for acquiring excellent mechanical properties and outstanding biocompatibility. To further improve the hemocompatibility of the AP-fixed PP, a natural and specific inhibitor of thrombin (hirudin) was introduced to achieve surface modification of the AP-fixed PP. The feasibility of crosslinking and functionalizing AP-fixed PP, which was a potential leaflet material of BHVs, was exhaustively and systematically evaluated. In vitro studies found that hirudin-loaded and AP-fixed PP (AP + Hirudin-PP) had synchronously achieved effective fixation of collagen, highly effective anticoagulation, and good HUVECs-cytocompatibility. In vivo results revealed that the AP + Hirudin-PP specimens recruited the minimum immune cells in the implantation experiment, and also presented an excellent anti-calcification effect. Overall, AP + Hirudin-PP was endowed with competitive collagen stability (compared with GA-fixed PP), excellent hemocompatibility, good HUVECs-cytocompatibility, low immunogenicity and outstanding anti-calcification, suggesting that AP + Hirudin-PP might be a promising alternative to GA-fixed PP and exhibited a bright prospect in the clinical applications of BHVs.

Endothelial cells injury and activation contribute to arteriovenous fistula (AVF) stenosis. Hirudin (Hiru) can inhibit the activity of thrombin, which was reported to enhance endothelial cell permeability and promote vascular inflammatory responses. RhoA/ROCK signaling pathway is also important in regulating vascular endothelial permeability. This study aimed to investigate the role of Hiru on the viability and permeability of human umbilical vein endothelial cells (HUVECs) following stimulation of serum from rat with chronic renal failure (CRF) and illustrated the effects of Hiru on RhoA/ROCK signaling. Wistar rats were randomly divided into control group and CRF group. Serum from each group was collected to stimulate HUVECs. Proliferation capability was estimated with Cell Count Kit-8 (CCK-8) assay. Transwell assay was performed to determine permeability. Cell apoptosis was examined using Tunel staining. Telomere length and telomerase activity were determined by qPCR. Moreover, the expression of RhoA, ROCK1 and ROCK2 was estimated via western blot. Results showed that the serum from CRF rat significantly inhibited cell viability while enhanced cell permeability and apoptosis. Different concentrations of Hiru prevented the above effects caused by CRF serum. Additionally, Hiru recovered the CRF serum-induced decreased telomere length and telomerase activity. Hiru also inhibited the protein expression of RhoA, ROCK1 and ROCK2, which were activated by CRF serum. Moreover, the ROCK inhibitor, Y27632, exhibited similar effects with Hiru. In conclusion, Hiru-restored HUVECs cell viability, telomere length and telomerase activity, suppressed permeability and apoptosis in the presence of CRF serum might depend on inactivating the RhoA/ROCK signaling.

Several leech species of the genera Hirudo, Hirudinaria, and Whitmania are widely used in traditional Chinese medicine (TCM) for the oral treatment of disorders associated with blood stasis. Among them, the non-hematophagous leech Whitmania pigra expresses a variety of components that have the potential to act on the vertebrate blood coagulation system.Whether the thrombin inhibitor hirudin, probably the most prominent leech-derived anticoagulant, is actually present in Whitmania pigra, is still a matter of debate. To answer that open question was the aim of the study.We identified several putative hirudin-encoding sequences in transcriptome data of Whitmania pigra. Upon gene synthesis and molecular cloning the respective recombinant proteins were expressed in Escherichia coli, purified, processed, and eventually functionally characterized for thrombin-inhibitory potencies in coagulation assays.We were successful in the identification and functional characterization of several putative hirudins in Whitmania pigra. Some, but not all, of these factors are indeed thrombin inhibitors. Whitmania pigra hence expresses both hirudins (factors that inhibit thrombin) and hirudin-like factors (that do not or only very weakly inhibit thrombin). Furthermore, we revealed the exon/intron structures of the corresponding genes. Coding sequences of some putative hirudins of Whitmania pigra were present also in transcriptome datasets of Hirudo nipponia, a hematophagous leech that is likewise used in TCM.Based on both structural and functional data we provide very strong evidence for the expression of hirudins in Whitmania pigra. This is the first description of hirudins in a non-hematophagous leech.

There is an increasing interest in the use of bivalirudin for pediatric extracorporeal membrane oxygenation (ECMO) anticoagulation. However, dosing is not well described in those requiring continuous renal replacement therapy (CRRT). We aimed to determine whether CRRT affects bivalirudin dosing in pediatric ECMO patients. Children ≤18 years of age placed on ECMO and anticoagulated with bivalirudin for ≥24 hours from January 2019 to May 2020 were included. Bivalirudin doses were collected for 144 hours from initiation of bivalirudin or CRRT. Analysis was performed to determine whether CRRT, age, or weight affected bivalirudin dosing. Thirty-one children were included, and 11 (35%) required concomitant CRRT. There was no difference in age (median 9.1 versus 3.2 months, p = 0.15) or days on ECMO (median 11 versus 9, p = 0.7) between those who did or did not receive CRRT. The mean bivalirudin dosing was similar in patients who did or did not require CRRT (median and IQR: 0.13 mg/kg/hour [0.08-0.26] versus 0.15 mg/kg/hour [0.11-0.22], respectively, p = 0.13). Younger age ( p0.001) and lower weight ( p0.001) were associated with higher bivalirudin dosing. In our study, bivalirudin dosing did not differ if the patient required CRRT while on ECMO.

Introduction and objectives Patients who are vulnerable to hemodynamic or electrical disorders (VP) are often excluded from clinical trials and data on the optimal access-site or antithrombotic treatment are limited. We assessed outcomes of transradial vs transfemoral access and bivalirudin vs unfractionated heparin (UFH) in VP with acute coronary syndrome undergoing invasive management. Methods The MATRIX trial randomized 8404 patients to radial or femoral access and 7213 patients to bivalirudin or UFH. Among them, 934 (11.1%) were deemed VP due to advanced Killip class (n = 808), cardiac arrest (n = 168), or both (n = 42). The 30-day coprimary outcomes were major adverse cardiovascular and cerebrovascular events (MACE: death, myocardial infarction, or stroke) and net adverse clinical events (NACE: MACE or major bleeding). Results MACE and NACE were similarly reduced with radial vs femoral access in VP and non-VP. Transradial access was also associated with consistent relative benefits in all-cause and cardiovascular mortality or Bleeding Academic Research Consortium (BARC) 3 or 5 bleeding with greater absolute benefits in VP. The effects of bivalirudin vs UFH on MACE and NACE were consistent in VP and non-VP. Bivalirudin was associated with lower all-cause and cardiovascular mortality in VP but not in non-VP, with borderline interaction testing. Bivalirudin reduced bleeding in both VP and non-VP with a larger absolute benefit in VP. Conclusions In acute coronary syndrome patients undergoing invasive management, the effects of randomized treatments were consistent in VP and non-VP, but absolute risk reduction with radial access and bivalirudin were greater in VP, with a 5- to 10-fold lower number needed to treat for benefits. Trial registry number: NCT01433627.

Oxidative stress plays a critical role in the progression of myocardial injury. Increasing evidence suggests that hiruidin can treat patients with cardio-injury. However, the mechanism of hirudin against myocardial infraction remains unknown. In the present study, we evaluated the potential role and mechanism of hirudin on both isoproterenol (ISO)-induced myocardial infraction (MI) in rats and Hypoxia-Reoxygenation model in H9C2 cells. Compared with the model group, hirudin apparently decreased the levels of myocardial Creatine Kinase Isoenzyme-MB (CK-MB), lactate dehydrogenase (LDH), and alleviated myocardial histopathological changes induced by ISO injection. The underlying mechanisms were revealed by the following observations: Hirudin exerted its cardioprotective effect via restoring super oxide dismutase (SOD), attenuating reactive oxygen species (ROS) and malondialdehyde (MDA). It induced the activation of Nuclear factor erythroid 2-related factor 2 (Nrf2) signal pathway through disrupting Keap1-Nrf2 complex, thus Nrf2 translocated from cytoplasm to nucleus to regulate Nrf2-dependent gene (HO-1, SOD) expressions. Furthermore, it should be noted that hirudin restored mitochondrial membrane potential in addition to cytochrome C-related apoptosis.

Synthesis and purification of peptide drugs for medical applications is a challenging task. The leech-derived factor hirudin is in clinical use as an alternative to heparin in anticoagulatory therapies. So far, recombinant hirudin is mainly produced in bacterial or yeast expression systems. We describe the successful development and application of an alternative protocol for the synthesis of active hirudin based on a cell-free protein synthesis approach. Three different cell lysates were compared, and the effects of two different signal peptide sequences on the synthesis of mature hirudin were determined. The combination of K562 cell lysates and the endogenous wild-type signal peptide sequence was most effective. Cell-free synthesized hirudin showed a considerably higher anti-thrombin activity compared to recombinant hirudin produced in bacterial cells.

We retrospectively compared anticoagulation with heparin and bivalirudin for 32 consecutive children under 18 years old during extracorporeal membrane oxygenation (ECMO) in our pediatric cardiac intensive care unit (PCICU). Between September 2015 and January 2018, 14 patients received heparin, 13 venoarterial (VA), and 1 venovenous (VV). From February 2018 to September 2019, 18 received bivalirudin (all VA). The mean (standard deviation [SD]) percentage of time with therapeutic activated partial thromboplastin time and activated clotting time was bivalirudin 54 (14%) and heparin 57 (11%), p = 0.4647, and percentage of time supratherapeutic was bivalirudin 18 (10%) and heparin 27 (12%), p = 0.0238. Phlebotomy-associated blood loss per hour of ECMO was double in the heparin compared with bivalirudin group 1.08 ml/h (0.20 ml/h), compared with 0.51 ml/h (0.07 ml/h), p = 0.0003, as well as interventions to control bleeding. Packed red blood cell (PRBC) transfusions significantly correlated with higher blood loss in the heparin group (Pearson correlation coefficient = 0.49, p = 0.0047). Overall amount of blood product utilization was not different between the groups. Survival to ECMO decannulation was 89% for bivalirudin and 57% for heparin, p = 0.0396, although 6 month survival was not significantly different (67% versus 57%, p = 0.5809). Heparin may increase the need for PRBC transfusions and strategies to attenuate bleeding when compared with bivalirudin for children receiving ECMO in PCICU.

OBJECTIVES Objective of this study was to determine if bivalirudin resulted in less circuit interventions than unfractionated heparin. A secondary objective was to examine associations between bivalirudin dose and partial thromboplastin time, international normalized ratio, and activated clotting time. DESIGN Prospective observational. SETTING Medical-surgical and cardiac PICUs. PATIENTS Neonatal and pediatric extracorporeal membrane oxygenation patients who received bivalirudin anticoagulation. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Twenty extracorporeal membrane oxygenation runs in 18 patients used bivalirudin; 90% were venoarterial. Median (interquartile range) age was 4.5 months (1.6-35 mo). Thirteen patients (72%) had an underlying cardiac diagnosis. Of the 20 runs using bivalirudin, 16 (80%) were initially started on unfractionated heparin and transitioned to bivalirudin due to ongoing circuit thrombosis despite therapeutic anti-Xa levels (n = 13), ongoing circuit thrombosis with unfractionated heparin greater than or equal to 40 U/kg/hr (n = 2), or absence of increase in ACT after bolus of 100 U/kg of unfractionated heparin and escalation of unfractionated heparin infusion (n = 1). Initial bivalirudin dose ranged from 0.2 to 0.5 mg/kg/hr; no bolus doses were used. Median (range) bivalirudin dose was 0.9 mg/kg/hr (0.15-1.6 mg/kg/hr). Median (interquartile range) time on extracorporeal membrane oxygenation was 226.5 hours (150.5-393.0 hr) including 84 hours (47-335 hr) on bivalirudin. Nonparametric results are as follows: the rate of circuit intervention was significantly lower in patients on bivalirudin than on unfractionated heparin (median [interquartile range]: 0 [0-1] and 1 [1-2], respectively; Wilcoxon p = 0.0126). Bivalirudin dose was correlated to PTT (rs = 0.4760; p < 0.0001), INR (rs = 0.6833; p < 0.0001), and ACT (rs = 0.6161; p < 0.0001). Four patients had a significant bleeding complication on bivalirudin. Survival to hospital discharge was 56%. CONCLUSIONS Bivalirudin appears to be a viable option for systemic anticoagulation in pediatric extracorporeal membrane oxygenation patients who have failed unfractionated heparin, but questions remain namely its optimal monitoring strategy. This pilot study supports the need for larger prospective studies of bivalirudin in pediatric extracorporeal membrane oxygenation, particularly focusing on meaningful monitoring variables.

Background For patients treated with dual antiplatelet therapy, standardized drug-specific 3-to-7 day cessation is recommended prior to major surgery to reach sufficient platelet function recovery. Here we investigated the hypothesis that supplemental fibrinogen might mitigate the inhibitory effects of antiplatelet therapy.Methods and Results To this end blood from healthy donors was treated in vitro with platelet inhibitors, and in vitro thrombus formation and platelet activation were assessed. Ticagrelor, acetylsalicylic acid, the combination of both, and tirofiban all markedly attenuated the formation of adherent thrombi, when whole blood was perfused through collagen-coated microchannels at physiological shear rates. Addition of fibrinogen restored in vitro thrombus formation in the presence of antiplatelet drugs and heparin. However, platelet activation, as investigated in assays of P-selectin expression and calcium flux, was not altered by fibrinogen supplementation. Most importantly, fibrinogen was able to restore in vitro thrombogenesis in patients on maintenance dual antiplatelet therapy after percutaneous coronary intervention.Conclusion Thus, our in vitro data support the notion that supplementation of fibrinogen influences the perioperative hemostasis in patients undergoing surgery during antiplatelet therapy by promoting thrombogenesis without significantly interfering with platelet activation.

There is a paucity of data regarding the use of direct thrombin inhibitors such as bivalirudin for children on extracorporeal life support (ECLS). We sought to compare the outcomes of children on ECLS anticoagulated with bivalirudin versus heparin. Patients transitioned from heparin to bivalirudin were treated as a separate group. A single-institution, retrospective review of all consecutive children (neonate to 18 years) placed on ECLS in the cardiac or pediatric intensive care units was performed (June 2018-December 2019). Data collected included demographics, anticoagulation strategy, number of circuit interventions, blood product use on ECLS, survival to decannulation, and survival to discharge. Fifty-four children were placed on ECLS for a total of 56 runs. Demographics and venovenous versus venoarterial ECLS were similar. The bivalirudin group had longer median duration of support compared to the heparin group--11.0 days [IQR 6.2, 23.1] versus 3.3 days [2.1, 6.2], P < .001. Patients switched from heparin to bivalirudin had a similar duration of support (10.3 days [8.3, 18.3]) as those on bilvalirudin alone. However, there was no difference in red blood cell, fresh frozen plasma, or platelet transfusions. There was no difference in the number of circuit interventions, survival to decannulation or discharge. The freedom to first circuit intervention was longer with bivalirudin compared to heparin. Our data suggest that even with longer pediatric ECLS runs on bivalirudin, there were no differences in the outcomes between the heparin and bivalirudin groups, with longer freedom from first circuit intervention with bivalirudin. While this is the largest reported series comparing children on ECLS anticoagulated with heparin versus bivalirudin, larger studies are needed to determine the optimal anticoagulation strategy for this diverse and complicated group of children.

OBJECTIVE To investigate the therapeutic and synergistic effects of QHC (combination of quercetin (Q), hirudin (H) and cinnamaldehyd (C)) on Schwann cell differentiation and myelination against high glucose (HG) induced injury. METHODS Primary-culture Schwann cells exposed to HG (50 mmol/L) for 72 h and Schwann cell-dorsal root ganglion (DRG) neuron cocultures exposed to HG (50 mmol/L) for 7 days were employed as in vitro model of diabetic neuropathy. The cells were randomly divided into 10 groups: control (CON, 25 mmol/L glucose), HG (50 mmol/L glucose), HG plus 10 μmol/L quercetin (Q), HG plus 0.04 IU/mL hirudin (H), HG plus 100 nmol/L cinnamaldehyd (C), HG plus 10 μmol/L quercetin and 0.04 IU/mL hirudin (QH), HG plus 10 μmol/L quercetin and 50 nmol/L cinnamaldehyd (QC), HG plus 0.04 IU/mL hirudin and 50 nmol/L cinnamaldehyd (HC), HG plus 10 μmol/L quercetin, 0.04 IU/mL hirudin and 50 nmol/L cinnamaldehyd (QHC) or 10 μmol/L U0126. Cell differentiation was evaluated by periaxin immunofluorescence staining. The protein expression levels of myelin protein zero (P0), myelin basic protein (MBP), myelin-associated glycoprotein (MAG), extracellular signal-regulated kinase (ERK), p-ERK, p-c-Jun, c-Jun, notch intracellular domain (NICD) and the mRNA expression levels of P0, MBP, MAG, Krox-20, Notch1 and Jagged1 were detected by Western blotting and real-time quantitative PCR analysis. The secretion of ciliary neurotrophic factor (CNTF) was determined by enzyme-linked immunosorbent assay (ELISA). The number and length of the myelin segments were evaluated by MBP immunofluorescence staining. The expression and the location of p-ERK in cocultures were detected by MAG and p-ERK immunofluorescence double staining. RESULTS Co-treatment with Q, C, H and their combination promoted Schwann cell differentiation, increased CNTF secretion, up-regulated the protein and mRNA expressions of myelin, and increased the number and length of the myelin segments (P

BACKGROUND Acute myocardial infarction (AMI) occurs when atherosclerotic lesions which present in the coronary arteries cause the intravascular plate to rupture and with the result of myocardial ischemia, hypoxia, and infarct. The preferred treatment for AMI is currently percutaneous coronary intervention (PCI), for which the key to the success is the choice of anticoagulant and thrombolytic drugs during surgery. Here, we aim to explore the effects of atorvastatin combined with bivalirudin on coagulation function, cardiac function, and inflammatory factors in elderly patients with AMI who underwent PCI. METHODS The clinical data of 86 AMI patients who were admitted to our hospital between February 2016 and May 2018 were retrospectively analyzed. Based on different treatments, the patients were divided into the control group and the observation group, with 43 patients in each group. The control group patients were treated with bivalirudin, and the observation group was treated with bivalirudin plus atorvastatin. Both groups of patients underwent PCI and the clinical efficacy, coagulation function, cardiac function, inflammatory factor levels and cardiovascular events (MACE), and other clinical data were compared between the groups. RESULTS The total clinical effective rate in the observation group was significantly higher than that in the control group (90.90% vs. 72.09%) (P

Objectives Heparin is the universal anticoagulant for patients receiving extracorporeal membrane oxygenation support. However, heparin has many disadvantages, especially in young children, who develop heparin resistance. Recently our center has used bivalirudin, a direct thrombin inhibitor, for systemic anticoagulation in pediatric extracorporeal life support. Bivalirudin binds directly to thrombin with no need for antithrombin III and it inhibits both circulating and clot-bound thrombin. In this study, we sought to evaluate our experience with bivalirudin in pediatric extracorporeal life support. Design Retrospective chart review study of patients receiving extracorporeal membrane oxygenation support between October 2014 and May 2018. Setting Tertiary, academic PICU. Patients Sixteen patients receiving heparin and 16 patients receiving bivalirudin on extracorporeal life support were included in the study. Interventions None. Measurements and main results Patients in the bivalirudin group had a median age of 31 months versus 59 months in the heparin group (p = 0.41). Recovery and extracorporeal membrane oxygenation decannulation were similar in both groups (56% in the heparin group and 62% in the bivalirudin group; p = 0.62). Time to reach goal therapeutic anticoagulation level was shorter in the bivalirudin group (11 vs 29 hr; p = 0.01). Bleeding events were fewer in the bivalirudin group, and there was no difference in the rate of thrombotic events between the two groups. Comprehensive cost analysis that includes anticoagulant, laboratories, and antithrombin III cost, showed that heparin anticoagulation therapy total cost was significantly higher than bivalirudin (1,184 dollars per day in heparin group vs 494 dollars per day in bivalirudin group; p = 0.03). Bivalirudin dose required to maintain target anticoagulation will increase over time, and this is associated with an increase in creatinine clearance and an increase in fibrinogen serum levels. Conclusions This study showed that the use of bivalirudin in pediatric extracorporeal membrane oxygenation support is feasible, safe, reliable, and cost-effective in comparison to heparin. Further prospective randomized clinical trials are necessary to confirm our observations.

Bleeding risk stratification is an unresolved issue in older adults. Anemia may reflect subclinical blood losses that can be exacerbated after percutaneous coronary intervention . We sought to prospectively determine the contribution of anemia to the risk of bleeding in 448 consecutive patients aged 75 or more years, treated by percutaneous coronary interventions without concomitant indication for oral anticoagulation. We evaluated the effect of WHO-defined anemia on the incidence of 1-year nonaccess site-related major bleeding. The prevalence of anemia was 39%, and 13.1% of anemic and 5.2% of nonanemic patients suffered a bleeding event (hazard ratio 2.75, 95% confidence interval 1.37 to 5.54, p = 0.004). Neither PRECISE-DAPT nor CRUSADE scores were superior to hemoglobin for the prediction of bleeding. In conclusion, anemia is a powerful predictor of bleeding with potential utility for simplifying tailoring therapies.

To investigate protective effects of hirudin on oxidative stress and apoptosis of spinal dorsal root ganglion cells in high-glucose rats at the cellular and molecular level. Dorsal root ganglion neurons (DRGn) were harvested from embryonic day in 15 SD rats, purified and identificated after primary culture. They were divided into the normal control group, high-glucose (HG) group, positive control (alpha-lipoic acid, ALA) group, low-dose hirudin group (H1), medium-dose hirudin group (H2) and high-dose hirudin group (H3). The control group was cultured by neuron specific culture medium, while the HG group was cultured by neuron specific culture medium and 20 mmol/L glucose (HG medium). The hirudin groups were cultured by HG medium+0.25 IU/mL hirudin (H1), HG medium+0.5 IU/mL hirudin (H2) and HG medium+1 IU/mL hirudin (H3). The ALA group was cultured by HG medium+100 µ mol/L ALA. 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenylt etrazolium bromide (MTT) assay was used to explore the optimum concentration and intervention time. Flow cytometry assay was used to detect the level of reactive oxygen series (ROS). Western blot and quantificational realtime polymerase chain reaction (qRT-PCR) were used to detect the expression of protein and mRNA of nuclear factor erythroid 2-related factor 2 (Nrf-2), hemeoxygence-1 (HO-1), nuclear factor-κ B (NF-κ B) and Caspase-3. TUNEL assay was used to test the apoptosis rate of different groups. After 24 h of culture, the cell activity of hirudin and ALA groups were higher than that of HG group, and there was a statistical difference between the H1 group and HG group (P

Introduction: Bivalirudin and heparin are the two most commonly used anticoagulants used during Percutaneous Coronary Intervention (PCI). The results of Randomized Controlled Trials (RCTs) comparing bivalirudin versus heparin monotherapy in the era of radial access are controversial, questioning the positive impact of bivalirudin on bleeding. The purpose of this systematic review is to summarize the results of RCTs comparing the efficacy and safety of bivalirudin versus heparin with or without Glycoprotein IIb/IIIa Inhibitors (GPI). Methods: This systematic review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses PRISMA statements for reporting systematic reviews. We searched the National Library of Medicine PubMed, Clinicaltrial.gov and the Cochrane Central Register of Controlled Trials to include clinical studies comparing bivalirudin with heparin in patients undergoing PCI. Sixteen studies met inclusion criteria and were reviewed for the summary. Findings: Several RCTs and meta-analyses have demonstrated the superiority of bivalirudin over heparin plus routine GPI use in terms of preventing bleeding complications but at the expense of increased risk of ischemic complications such as stent thrombosis. The hypothesis of post- PCI bivalirudin infusion to mitigate the risk of acute stent thrombosis has been tested in various RCTs with conflicting results. In comparison, heparin offers the advantage of having a reversible agent, of lower cost and reduced incidence of ischemic complications. Conclusion: Bivalirudin demonstrates its superiority over heparin plus GPI with better clinical outcomes in terms of less bleeding complications, thus making it as anticoagulation of choice particularly in patients at high risk of bleeding. Further studies are warranted for head to head comparison of bivalirudin to heparin monotherapy to establish an optimal heparin dosing regimen and post-PCI bivalirudin infusion to affirm its beneficial effect in reducing acute stent thrombosis.

The use of percutaneous ventricular assist devices (VADs) in the acute management of cardiogenic shock is becoming increasingly common. The Impella is a percutaneous VAD, which requires a heparin-containing purge solution to prevent thrombosis and maintain proper pump functionality. In this report, we describe two patients with heparin-induced thrombocytopenia (HIT) supported with an Impella using a bivalirudin-containing purge solution. Case 1 involved a 39-year-old man with cardiogenic shock, initially implanted with an intraaortic balloon pump, who developed HIT early in his hospital course. His worsening hemodynamics necessitated the placement of an Impella and later venoarterial extracorporeal membrane oxygenation until he eventually underwent durable left VAD implantation. Case 2 involved a 69-year-old man who had an Impella implanted for worsening cardiogenic shock. HIT was suspected shortly after device insertion, necessitating switching his anticoagulation to bivalirudin. He was successfully bridged directly to heart transplantation. Both patients' courses resulted in therapeutic anticoagulation without major bleeding or thrombotic events. These cases demonstrate the safe and effective use of bivalirudin-containing purge solutions for patients with confirmed HIT requiring temporary mechanical circulatory support with Impella.

Objectives We sought to evaluate the efficacy and safety of bivalirudin versus heparin in patients with coronary artery disease undergoing transradial artery coronary intervention (TRI). Background Bivalirudin and radial artery access are independently associated with improved cardiovascular outcomes. However, data supporting a strategy of combining both to achieve additive improvements in cardiovascular outcomes provide conflicting results. Methods A systematic search was performed to identify randomized controlled trials (RCTs) of bivalirudin, in which vascular access sites were reported. The primary outcome was net adverse clinical events (NACE) at 30 days. Secondary outcomes were long-term NACE, short-, and long-term major adverse cardiovascular events, all-cause mortality, myocardial infarction, unplanned revascularization, stent thrombosis, and major bleeding. Results We identified 10 RCTs, including 16,328 patients who underwent TRI (mean age 64.6 ± 15.7 years, 72.5% male). Bivalirudin use was associated with decreased 30-day NACE compared with heparin (6.3 vs. 7.4%; risk ratio [RR] = 0.87; 95% confidence interval [CI] = 0.76-0.99; p = .04; number needed to treat = 91). No significant interactions were observed based on clinical presentation, administration of P2Y12 inhibitors, or glycoprotein IIb/IIIa-receptor inhibitors (GPI) use. There were no significant differences between groups in any prespecified secondary outcomes. There was, however, a significant reduction of major bleeding in the bivalirudin group compared with heparin when used in combination with routine GPI (RR = 0.41; 95% CI = 0.19-0.90; p = .03). Conclusions Among patients undergoing TRI, use of bivalirudin was associated with significantly reduced 30-day NACE compared with heparin. There was no significant difference in long term NACE, ischemic, or bleeding events compared with heparin.

Introduction Bivalirudin is an alternative to heparin anticoagulation in infants and children in the setting of extracorporeal life support (ECLS). While activated partial thromboplastin time (aPTT) is widely accepted as the standard test to monitor bivalirudin therapy, the usefulness of thromboelastometry (ROTEM) to monitor bivalirudin infusion in the setting of ECLS is unknown. Objective We aimed to assess the utility of ROTEM in monitoring hemostasis and bivalirudin effect in children on either extracorporeal membrane oxygenation (ECMO) or ventricular assist devices (VAD) compared to standard plasma based coagulation assays. Methods A retrospective study of children undergoing bivalirudin infusion for ECMO/VAD support from a tertiary care pediatric hospital (January 2017–June 2018) was performed. ROTEM assays for extrinsic (EXTEM) and intrinsic (INTEM) coagulation pathways, INTEM with heparinase (HEPTEM), fibrin formation (FIBTEM) with measurement of the clotting time (CT) and maximum clot firmness (MCF) were compared to routine hemostasis testing including: aPTT, aPTT Hepzyme (HPTT), prothrombin time (PT), fibrinogen and platelet count. Results One hundred and six blood samples from 18 children were tested. There was a strong positive correlation between HPTT and HEPTEM CT, and moderate correlation between aPTT and INTEM CT. The bivalirudin dose did not correlate with any test, but displayed strong age-dependence, with infants requiring higher doses of bivalirudin to maintain therapeutic targets. Excellent correlation was found between FIBTEM MCF values and fibrinogen, but FIBTEM overestimated fibrinogen level when platelet count was >300 × 109/L. Heparin-like effect was identified in 39% of specimens, and an improved correlation between aPTT and INTEM CT was observed in specimens without heparinoids. Conclusions In the setting of bivalirudin therapy, prolongation of CT on INTEM and HEPTEM showed moderate to strong correlation with aPTT and HPTT, and therefore, may provide a good alternative to these assays. In addition, HPTT and HEPTEM CT might be preferable for monitoring bivalirudin in the setting of ECLS due to frequent detection of heparin-like effect.

Anticoagulation in a neonate is a challenge and the availability of anticoagulant options is extremely limited. Here we describe the use of a direct thrombin inhibitor, bivalirudin, in a full-term neonate with symptomatic cerebral sinovenous thrombosis complicated by bilateral thalamic hemorrhagic stroke and intraventricular hemorrhage, who could not be effectively treated with sodium heparin due to heparin resistance (HR) and showed thrombosis regression after start of bivalirudin treatment, without worsening of the hemorrhage. While the use of bivalirudin in neonates has been previously described, the indication of cerebral sinovenous thrombosis and the setting of HR are unique.

Thromboembolic disease is a common cardio-cerebral vascular disease that threatens human life and health. Thrombin not only affects the exogenous coagulation pathway, but also the endogenous pathway. Thus, it becomes one of the most important targets of anticoagulant drugs. RGD-hirudin is an anticoagulant drug targeting thrombin, but it can only be administered intravenously. We designed a low molecular weight peptide based on RGD-hirudin that could prevent blood clots. We first used NMR to identify the key amino acid residues of RGD-hirudin that interacted with thrombin. Then, we designed a novel direct thrombin inhibitor peptide (DTIP) based on the structure and function of RGD-hirudin using homology modeling. Molecular docking showed that the targeting and binding of DTIP with thrombin were similar to those of RGD-hirudin, suggesting DTIP interacted directly with thrombin. The active amino acids of DTIP were identified by alanine scanning, and mutants were successfully constructed. In blood clotting time tests in vitro, we found that aPTT, PT, and TT in the rat plasma added with DTIP were greatly prolonged than in that added with the mutants. Subcutaneous injection of DTIP in rats also could significantly prolong the clotting time. Thrombelastography analysis revealed that DTIP significantly delayed blood coagulation. Bio-layer interferometry study showed that there were no significant differences between DTIP and the mutants in thrombin affinity constants, suggesting that it might bind to other sites of thrombin rather than to its active center. Our results demonstrate that DTIP with low molecular weight can prevent thrombosis via subcutaneous injection.

Medicinal leeches have been used in health care since before written history, with widely varying popularity over the centuries. Nowadays, medicinal leech therapy is mainly used in plastic and reconstructive microsurgery, with new interesting potential therapeutic applications in many other diseases. The leech's best-known salivary product, hirudin — one of the most powerful natural anticoagulants — was the only remedy to prevent blood clotting until the discovery of heparin. Starting from hirudin, pharmacological research succeeded in developing new anticoagulants, which represent a cornerstone of prevention and treatment of thromboembolic disease. While we are perhaps on the threshold of a new era of anticoagulation, with the development of FXI and XII inhibitors and direct reversible covalent thrombin inhibitors, which promise to achieve effective anticoagulation without bleeding risk. This review retraces the intriguing journey of these drugs in cardiovascular disease, highlighting the fil rouge that links the ancient leech to the current and oncoming antithrombotic therapy. We think that knowledge of the past is key to understanding and appreciating the present and to seize future opportunities.

International journal of molecular sciences 23(18), 10203 (2022). doi:10.3390/ijms231810203 special issue: "Special Issue "Molecular Mechanisms of Hemostasis, Thrombosis and Thrombo-Inflammation 2.0" / Special Issue Editors: Dr. Kerstin Jurk, Guest Editor; Dr. Marijke J.E. Kuijpers, Guest Editor; Prof. Dr. Johan W. M. Heemskerk, Guest Editor", Published by Molecular Diversity Preservation International, Basel

Aims The efficacy and safety of continued bivalirudin infusion after percutaneous coronary intervention (PCI) remains uncertain. We sought to investigate the association between post-PCI bivalirudin infusion and the risk of net adverse clinical events (NACE) at 30 days. Methods and results In the GLOBAL LEADERS study, all patients who received bivalirudin during PCI were categorized according to the use of bivalirudin infusion after the procedure. The primary endpoint of the present analysis was NACE [a composite of all-cause death, any stroke, any myocardial infarction, all revascularization, and bleeding assessed according to the Bleeding Academic Research Consortium (BARC) criteria Type 3 or 5] at 30 days. The key safety endpoint was BARC Type 3 or 5 bleeding and definite stent thrombosis. Of 15 968 patients, 13 870 underwent PCI with the use of bivalirudin. In total, 7148 patients received continued bivalirudin infusion after procedure, while 6722 patients received standard care. After propensity score covariate adjustment, the risk of NACE did not significantly differ between two treatments after PCI [continued bivalirudin infusion vs. no bivalirudin infusion: 3.2% vs. 3.1%, adjusted hazard ratio (aHR) 1.35, 95% confidence interval (CI) 0.99–1.84, P = 0.06] nor the BARC Type 3 or 5 bleeding (0.7% vs. 0.7%, aHR 0.89, 95% CI 0.44–1.79; P = 0.743) and definite stent thrombosis (0.5% vs. 0.3%, aHR 1.71, 95% CI 0.77–3.81, P = 0.189). However, continued bivalirudin infusion was associated with an increased risk of NACE and definite stent thrombosis in ST-elevation myocardial infarction (STEMI) patients. Conclusion In an all-comers population undergoing PCI, there was no significant difference in the risk of NACE at 30 days between continued bivalirudin infusion vs. no bivalirudin infusion after procedure but continued bivalirudin infusion was associated with a higher risk of NACE in STEMI patients when compared with no infusion.

Heparin-induced thrombocytopenia (HIT) type-2 is a rare, but life-threatening complication that presents a unique challenge in patients undergoing cardiac surgery. Patients that require cardiac surgery with HIT present a dilemma between intraoperative anticoagulation, perioperative bleeding risk, and perioperative thrombotic events. We describe a case series of four patients who developed HIT in their hospital course before HeartMate 3 (HM3) left ventricular assist device implantation. Following a multidisciplinary approach, all patients did well intraoperatively with an approach of preoperative plasmapheresis, intraoperative unfractionated heparin (UFH), and postoperative conversion to bivalirudin with a bridge to warfarin. However, two patients had postoperative bleeding complications on bivalirudin. This case series details the therapeutic challenges encountered for HM3 implantation in patients with HIT and offers a therapeutic alternative to intraoperative bivalirudin in the effort to decrease perioperative complications in this challenging patient population.

Background: Bivalirudin was not superior to unfractionated heparin in patients with myocardial infarction (MI) treated with percutaneous coronary intervention and no planned use of GPI (glycoprotein IIb/IIIa inhibitors) in contemporary clinical practice of radial access and potent P2Y 12 -inhibitors in the VALIDATE-SWEDEHEART randomized clinical trial (Bivalirudin Versus Heparin in STEMI and NSTEMI Patients on Modern Antiplatelet Therapy–Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies Registry). Methods: In this prespecified separately powered subgroup analysis, we included patients with ST-segment–elevation MI undergoing primary percutaneous coronary intervention with the primary composite end point of all-cause death, MI, or major bleeding event within 180 days. Results: Among the 6006 patients enrolled in the trial, 3005 patients with ST-segment–elevation MI were randomized to receive bivalirudin or heparin. The mean age was 66.8 years. According to protocol recommendations, 87% were treated with potent oral P2Y 12 -inhibitors before start of angiography and radial access was used in 90%. GPI was used in 51 (3.4%) and 74 (4.9%) of patients randomized to receive bivalirudin and heparin, respectively. The primary end point occurred in 12.5% (187 of 1501) and 13.0% (196 of 1504; hazard ratio [HR], 0.95 [95% CI, 0.78–1.17], P =0.64) with consistent results in all major subgroups. All-cause death occurred in 3.9% versus 3.9% (HR, 1.00 [0.70–1.45], P =0.98), MI in 1.7% versus 2.2% (HR, 0.76 [0.45–1.28], P =0.30), major bleeding in 8.3% versus 8.0% (HR, 1.04 [0.81–1.33], P =0.78), and definite stent thrombosis in 0.5% versus 1.3% (HR, 0.42 [0.18–0.96], P =0.04). Conclusions: In patients with ST-segment–elevation MI undergoing primary percutaneous coronary intervention with radial access and receiving current recommended treatments with potent P2Y 12 -inhibitors rate of the composite of all-cause death, MI, or major bleeding was not lower in those randomized to receive bivalirudin as compared with heparin. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02311231.