Recombinant supercharged polypeptides for safe and efficient heparin neutralization.

Heparin is a widely used anticoagulant agent in the clinic. After application, its anticoagulant effect must be reversed to prevent potential side effects. Protamine sulfate (PS) is the only clinically licensed antidote that has been used for this purpose in the last 80 years, which, however, provokes severe adverse effects, such as systemic hypotension and even death. Herein, we demonstrate the potential of supercharged polypeptides as a promising alternative for protamine sulfate. A series of supercharged polypeptides with multiple positive charges was recombinantly produced, and the heparin-neutralizing performance of the polypeptides was evaluated in comparison with PS. It was found that increasing the number of charges significantly enhanced the ability to neutralize heparin and resist the screening effect induced by salt. In particular, the polypeptide bearing 72 charges (K72) exhibited an excellent heparin-neutralizing behavior that was comparable to that of PS. Further in vivo studies revealed that the heparin-triggered bleeding was almost completely alleviated by K72 while a negligible toxic effect was observed. Therefore, such recombinant supercharged polypeptides might replace protamine sulfate as heparin-reversal agents.

Safety of routine protamine in the reversal of heparin in percutaneous coronary intervention: A systematic review and meta-analysis.

OBJECTIVES: To determine the safety and efficacy of protamine in the reversal of heparin in percutaneous coronary intervention (PCI). BACKGROUND: Heparin is routinely used for anticoagulation in PCI. Protamine is not used routinely to reverse heparin's effects in PCI, partly due to the perceived risk of stent thrombosis. METHODS: Relevant studies published in English were searched for in PubMed, Embase, and Cochrane databases from inception to April 26th, 2023. Our primary outcome of interest was stent thrombosis in patients receiving PCI for all indications. Secondary outcomes included mortality, major bleeding complications, and hospitalization length. Dichotomous outcomes were analyzed using a Mantel-Haenszel random-effects model and expressed as odds ratios (OR) with their 95% confidence intervals (CI), while continuous outcomes were analyzed using an inverse variance random-effects model expressed as mean differences (MD) with their 95% CI. RESULTS: 11 studies were included in our analysis. Protamine use was not associated with stent thrombosis: OR 0.58, 95% CI: 0.33, 1.01 (p = 0.05) nor with mortality (p = 0.89). Protamine administration was associated with a decreased incidence of major bleeding complications: OR 0.48; 95% CI: 0.25, 0.95 (p = 0.03) and decreased length of hospitalization (p < 0.0001). CONCLUSIONS: In patients pre-treated with dual antiplatelet therapy (DAPT), protamine may be a safe and efficacious option to facilitate earlier sheath removal, reduce major bleeding complications, and reduce length of hospitalization without increased risk of stent thrombosis.

Topical coapplication of hyaluronan with transdermal drug delivery enhancers attenuates inflammatory and neuropathic pain.

ABSTRACT: We have previously shown that intradermal injection of high-molecular-weight hyaluronan (500-1200 kDa) produces localized antihyperalgesia in preclinical models of inflammatory and neuropathic pain. In the present experiments, we studied the therapeutic effect of topical hyaluronan, when combined with each of 3 transdermal drug delivery enhancers (dimethyl sulfoxide [DMSO], protamine or terpene), in preclinical models of inflammatory and neuropathic pain. Topical application of 500 to 1200 kDa hyaluronan (the molecular weight range used in our previous studies employing intradermal administration), dissolved in 75% DMSO in saline, markedly reduced prostaglandin E 2 (PGE 2 ) hyperalgesia, in male and female rats. Although topical 500- to 1200-kDa hyaluronan in DMSO vehicle dose dependently, also markedly, attenuated oxaliplatin chemotherapy-and paclitaxel chemotherapy-induced painful peripheral neuropathy (CIPN) in male rats, it lacked efficacy in female rats. However, following ovariectomy or intrathecal administration of an oligodeoxynucleotide antisense to G-protein-coupled estrogen receptor (GPR30) mRNA, CIPN in female rats was now attenuated by topical hyaluronan. Although topical coadministration of 150 to 300, 300 to 500, or 1500 to 1750 kDa hyaluronan with DMSO also attenuated CIPN, a slightly lower-molecular-weight hyaluronan (70-120 kDa) did not. The topical administration of a combination of hyaluronan with 2 other transdermal drug delivery enhancers, protamine and terpene, also attenuated CIPN hyperalgesia, an effect that was more prolonged than with DMSO vehicle. Repeated administration of topical hyaluronan prolonged the duration of antihyperalgesia. Our results support the use of topical hyaluronan, combined with chemically diverse nontoxic skin penetration enhancers, to induce marked antihyperalgesia in preclinical models of inflammatory and neuropathic pain.

Temporal Trends and Contemporary Regional Variation in Management of Patients Undergoing Carotid Endarterectomy.

INTRODUCTION: The purpose of this study is to investigate regional variation and temporal trends in seven quality metrics amongst CEA patients: discharge on antiplatelet after CEA; discharge on statin after CEA; protamine administration during CEA; patch placement at conventional CEA site; continued statin usage at the time of most recent follow-up; continued antiplatelet usage at the time of most recent follow-up; and smoking cessation at the time of long term follow up. METHODS: There are 19 de-identified regions within the VQI database in the United States. Patients were placed into one of three temporal eras based on the time of their CEA: 2003-2008; 2009-2015; and 2016-2022. We first investigated temporal trends across the seven quality metrics for all regions combined on a national basis. The percentage of patients in each time era with the presence/absence of each metric was identified. Chi-squared testing was performed to confirm statistical significance of the differences across eras. Next, analysis was performed within each region and within each time metric. We separated out the 2016-2022 patients within each region to serve as the status of each metric application in the most modern era. We then compared the frequency of metric non-adherence in each region utilizing Chi-squared testing. RESULTS: There was statistically significant improvement in achievement of all seven metrics between the initial 2003-2008 era and the modern 2016-2022 era. The most marked change in practice pattern was noted for lack of protamine usage at surgery (decreased from 48.7% to 25.9%), discharge home postoperatively without statin (decreased from 50.6% to 15.3%), and lack of statin usage confirmed at time of most recent long term follow up (decreased from 24% to 8.9%). Significant regional variation exists across all metrics (P < .01 for all). Lack of patch placement at the time of conventional endarterectomy ranges from 1.9% to 17.8% across regions in the modern era. Lack of protamine utilization ranges from 10.8% to 49.7%. Lack of antiplatelet and statin at the time of discharge varies from 5.5% to 8.2% and 4.8% to 14.4% respectively. Adherence to the various measures at the time of most recent follow up are more tightly aligned across regions with ranges of: 5.3% to 7.5% for lack of antiplatelet usage; 6.6% to 11.7% lack of statin utilization; and 13.3 to 15.4% for persistent smoking. CONCLUSIONS: Prior studies and societal initiatives on CEA documenting the beneficial effects of patch angioplasty, protamine use at surgery, smoking cessation, antiplatelet utilization and statin compliance have positively impacted adherence to these measures over time. In the modern 2016-2022 era the widest regional variation is noted in patch placement, protamine utilization and discharge medications allowing individual geographic areas to identify areas for potential improvement via internal VQI administrative feedback.

The contemporary role of protamine in the cardiac catheterization laboratory.

Access to the arterial circulation and full anticoagulation carries a risk of serious bleeding during and after percutaneous coronary intervention. Important sources of bleeding include the arterial access site and coronary artery perforation. Prompt and effective management of hemorrhagic complications is an essential interventional skill. Protamine sulfate is well-known as a heparin reversal agent. Despite this, there is heterogeneity in the use of protamine during interventional procedures. While protamine is generally well-tolerated, it is associated with a risk of hypersensitivity reaction, including anaphylaxis, among others. The purpose of this review is to summarize the existing evidence about and experience with the use of protamine sulfate in the setting of percutaneous coronary and structural interventional procedures.

Acute Intraoperative Bioprosthetic Valve Thrombosis Immediately After Protamine Administration.

Acute bioprosthetic valve thrombosis (BPVT) is considered a rare complication and has seldom been described. Moreover, acute intraoperative BPVT is exceedingly rare, and its management remains a major clinical challenge. Here, we report a case of acute intraoperative BPVT that occurred immediately after protamine administration. Major resolution of the thrombus and significant improvement of bioprosthetic function were observed after the resumption of cardiopulmonary bypass support for approximately 1 hour. Intraoperative transesophageal echocardiography is important for a prompt diagnosis. Our case describes the spontaneous resolution of BPVT after reheparinization, which might assist in the management of acute intraoperative BPVT.

Association of postoperative atrial fibrillation with higher dosing ratios of protamine-to-heparin.

Background: Postoperative atrial fibrillation (POAF) is defined as new-onset AF in the immediate postoperative period. The relatively high incidence of POAF after cardiac surgery is well described, but pathophysiological mechanisms underlying the initiation, maintenance, and progression of POAF may be multifactorial and have not yet been comprehensively characterized. One of the mechanisms includes altered Ca2+ kinetics. Accumulating evidence has suggested that altered atrial cytosolic calcium handling contributes to the development of POAF, protamine reversibly modulates the calcium release channel/ryanodine receptor 2 (RyR2) and voltage-dependent cardiac RyR2. However, it is currently unknown whether such abnormalities contribute to the arrhythmogenic substrate predisposing patients to the development of POAF. Methods: We have retrospectively analyzed 147 patients who underwent cardiac surgery with cardiopulmonary bypass support. Of these, 40 patients were excluded from the analysis because of pre-existing AF. All patients received heparin followed by protamine at different dosing ratios of protamine-to-heparin, depending on the periods studied. Results: The dosing ratio of protamine-to-heparin = 1.0 was compared with higher dosing ratios of protamine-to-heparin >1.0 up to 1.7. POAF developed in 15 patients (15/107 = 14%), of these, 5 out of 57 patients (33.3%) in the dosing ratio of protamine-to-heparin = 1.0 and 10 out of 35 patients (66.7%) in the higher dosing ratios of protamine-to-heparin. Statistical significance was observed in patients with higher dosing ratios of protamine-to-heparin, compared with the dosing ratio of protamine-to-heparin = 1.0 (odds ratio = 3.890, 95% CI = 1.130-13.300, p-value = 0.031). When types of diseases were analyzed in terms of higher dosing ratios of protamine-to-heparin, only valvular disorders were significantly associated with POAF (p = 0.04). Conclusions: Protamine is clinically utilized to reverse heparin overdose and has been shown to display immunological and inflammatory alterations. However, its association with POAF has not been reported. Our results provide evidence that higher dosing ratios of protamine-to-heparin may increase the incidence of POAF.

Optimal protamine-to-heparin dosing ratio for the prevention of bleeding complications in patients undergoing TAVR-A multicenter experience.

BACKGROUND: Despite major advances, transcatheter aortic valve replacement (TAVR) is still associated with procedure-specific complications. Although previous studies reported lower bleeding rates in patients receiving protamine for heparin reversal, the optimal protamine-to-heparin dosing ratio is unknown. HYPOTHESIS: The aim of this study was a comparison of two different heparin antagonization regimens for the prevention of bleeding complications after TAVR. METHODS: The study included 1446 patients undergoing TAVR, of whom 623 received partial and 823 full heparin antagonization. The primary endpoint was a composite of 30-day mortality, life-threatening, and major bleeding. Safety endpoints included stroke and myocardial infarction at 30 days. RESULTS: Full antagonization of heparin resulted in lower rates of the primary endpoint as compared to partial heparin reversal (5.6% vs. 10.4%, p < .01), which was mainly driven by lower rates of life-threatening (0.5% vs. 1.6%, p = .05) and major bleeding (3.2% vs. 7.5%, p < .01). Moreover, the incidence of major vascular complications was significantly lower in patients with full heparin reversal (3.5% vs. 7.5%, p < .01). The need for red-blood-cell transfusion was lower in patients receiving full as compared to partial heparin antagonization (10.4% vs. 15.9%, p < .01). No differences were observed in the incidence of stroke and myocardial infarction between patients with full and partial heparin reversal (2.2% vs. 2.6%, p = .73 and 0.2% vs. 0.4%, p = .64, respectively). CONCLUSIONS: Full heparin antagonization resulted in significantly lower rates of life-threatening and major bleeding after TAVR as compared to partial heparin reversal. The occurrence of stroke and myocardial infarction was low and comparable between both groups.

Protamine-induced Acute Thrombosis in a Post-TAVR Patient: A Word of Caution.

Major vascular complications after transcatheter aortic valve replacement (TAVR) are a pertinent issue and associated with increased morbidity and mortality. We herein describe a case of acute limb ischemia following the administration of protamine sulfate (PS) that was administered to mitigate a bleeding complication post-failure of a vascular access closure device. PS should be used cautiously for the prevention or management of bleeding-site complications following TAVR. The patient described in this case has consented to having his case described in this manuscript.

Effectiveness and Safety of Idarucizumab for Periprocedural Cardiac Tamponade After Catheter Ablation of Atrial Fibrillation in Dabigatran Recipients: A Retrospective Controlled Study.

OBJECTIVE: This study aimed to investigate the effectiveness and safety of idarucizumab for periprocedural cardiac tamponade after catheter ablation of atrial fibrillation (AF) in patients treated with dabigatran. METHODS: We retrospectively studied 28 patients who received catheter ablation of AF and developed periprocedural cardiac tamponade. Patients were divided into two groups: control group (14 cases) and the study group (14 cases). Patients in the control group were administered warfarin bridged with low molecular weight heparin, while patients in the study group were given dabigatran for anticoagulation. Heparin was used for anticoagulation during surgery in both groups. Patients with cardiac tamponade in control group was reversed with protamine and the ones in study group were given protamine and idarucizumab. In the two groups, operative time, time to resume anticoagulation, bleeding time, length of hospital stay, hemodynamic parameters, coagulation function parameters, number of patients undergoing thoracotomy for hemostasis, pericardiocentesis drainage volume, and pericardial drainage retention time were recorded. RESULTS: There was no statistical difference in operative time and length of hospital stay between the two groups (p > 0.05); however, time to resume anticoagulation and bleeding time were significantly lower in the study group than in the control group, with a statistical difference (p < 0.05). After anticoagulation therapy, there was no apparent change and no statistical difference in the hemodynamic parameters and SaO2 between the two groups (p > 0.05). The pericardial drainage volume retention time was significantly shorter in the study group than in the control group, with a statistical difference (p < 0.05). CONCLUSION: Idarucizumab can rapidly and effectively reverse the anticoagulant effect of dabigatran in patients with AF who have periprocedural cardiac tamponade after catheter ablation.

Safety and efficacy of immediate heparin reversal with protamine after complex percutaneous coronary intervention.

BACKGROUND: Compared to simple percutaneous coronary intervention (PCI), complex PCI is associated with higher bleeding and thrombotic risk. No previous study has evaluated the use of protamine after PCI with contemporary technologies. This study aimed to evaluate the safety and efficacy of manual compression with and without protamine after transfemoral complex PCI. METHODS: We retrospectively analyzed 160 patients (protamine group, n = 92; non-protamine group, n = 68) who underwent complex PCI via the femoral artery. The primary outcome was a composite of in-hospital death, myocardial infarction, stent thrombosis, stroke/systemic embolism, bleeding requiring blood transfusion, and vascular access complications. RESULTS: The primary outcome was significantly lower in the protamine group than in the non-protamine group (4.3% vs. 17.6%; p = 0.006). This was driven mainly by the lower incidences of hematoma in the protamine group (3.3% vs. 13.2%, p = 0.020). Furthermore, the protamine group had a significantly shorter hospital stay than the non-protamine group (4.8 ± 3.7 days vs. 8.4 ± 8.3 days, p = 0.001). While > 90% of the patients had acute coronary syndrome, there were no incidences of myocardial infarction or stent thrombosis in either group. CONCLUSIONS: Among patients who underwent complex PCI via transfemoral access, immediate protamine administration was associated with a significantly lower rate of vascular access complications, especially hematoma, and shorter hospital stay than no protamine administration.

Nursing Observation of Improved Administration Route of Protamine Sulfate Neutralizing Heparin.

In this study, we have evaluated and examined various nursing effects of improved administration of protamine sulfate neutralizing heparin after cardiopulmonary bypass. For this purpose, retrospective analysis was made about the nursing records and clinical data of 216 patients who underwent cardiac operation under cardiopulmonary bypass in our hospital from January 2018 to December 2020. Among the enrolled patients, 118 patients were given subinterval administration of protamine sulfate neutralizing heparin via aortic root with the assistance of the scrub nurse at the end of cardiac surgery (improved group). A total of 98 patients were administered by the circulating nurse via the central vein (regular group). The changes of body temperature, blood pressure, oxygen saturation before and after heparin neutralization, and the total volume of thoracic drainage within 24 hours after operation were observed in the two groups, so as to evaluate the application effect of the improved administration of protamine sulfate neutralizing heparin from the perspective of nursing. There was no significant difference in age, gender, and other basic characteristics between the two groups (P > 0.05). The volume of drainage in the improved group and the regular group within 24 hours after surgery was 234 ± 26.3 ml and 307 ± 31.8 ml, respectively, P < 0.01, and the difference was statistically significant. The incidence of adverse reactions in the improved group was much lower than that in the regular group, P < 0.01. The administration route of the improved group was beneficial to maintain the stability of hemodynamics when using the protamine sulfate to neutralize heparin, which is worthy of clinical nursing promotion.

Periprocedural outcomes of protamine administration after catheter ablation of atrial fibrillation.

BACKGROUND: Perioperative anticoagulation management with uninterrupted or minimally interrupted anticoagulation during atrial fibrillation (AF) ablation is thought to be critical to minimize thromboembolic complications. Protamine is often administered to neutralize the effects of heparin and expedite vascular hemostasis post-procedure. OBJECTIVE: We performed a systematic review and meta-analysis to determine the effectiveness of protamine to expedite vascular hemostasis and ambulation in patients undergoing AF ablation. METHODS: Electronic searches on PubMed, The Cochrane Library, EMBASE, EBSCO, Web of Science, and CINAHL databases from the inception through August 7, 2021, were performed. The primary outcomes included-time to hemostasis (minutes) and time to ambulation (minutes). The secondary outcomes included - any vascular complications (excluding minor hematoma), minor hematoma, or cerebrovascular accidents (CVA). RESULTS: A total of 5 eligible studies (3 retrospective cohort studies and two randomized trials) consisting of 1012 patients (515 patients received protamine group and 497 patients did not receive protamine group) were included in the meta-analysis. There was a significant reduction in time to ambulation [weighted mean difference (WMD) -176.6 minutes, 95% Confidence interval (CI) -266.9 to -86.3; p < 0.01] and time to hemostasis (WMD -13.72 minutes, 95% CI -22 to -5.4, p < 0.01) in the protamine group compared to the contrary. At a follow-up up to 3 months, there was no statistical difference between the two groups with regards to vascular complications (2.9% vs. 7.4%; Risk ratio (RR) 0.46 95% CI 0.17 to 1.24; p = 0.12), minor hematoma (2.1% vs. 5.8%; RR 0.43, 95% CI 0.16 to 1.2; p = 0.11) or CVA (0 vs. 0.3%; RR 0.62, 95% CI 0.08 to 4.98; p = 0.65). CONCLUSION: Protamine administration was associated with reduced time to ambulation (176 minutes reduction) and time to hemostasis (13 minutes reduction) without an increase in any adverse events.

The Triple HIT: Perioperative Management of Heparin-Induced Thrombocytopenia Using Plasma Exchange, Intravenous Immunoglobulin, and Protamine Infusion for Left Ventricular Assist Device Implantation.

Heparin-induced thrombocytopenia (HIT) is a serious complication in patients exposed to heparin, leading to thrombocytopenia and, potentially, thrombosis. This disorder is challenging in cardiac surgery when anticoagulation for cardiopulmonary bypass is required. Herein a patient with HIT who had active thrombosis and successfully underwent urgent left ventricular assist device implantation managed with plasma exchange, intravenous immunoglobulin, and protamine infusion is described. These therapies reduce the immune response to heparin and minimize thrombosis when heparin reexposure is planned. These approaches to perioperative management of HIT represent an attractive alternative to the use of non-heparin anticoagulants in the cardiac and vascular surgical population.

Protamine-Induced Coronary Graft Thrombosis: A Review.

Perioperative myocardial infarction is a serious complication affecting a significant portion of patients undergoing coronary artery bypass graft surgery. This may arise due to coronary graft thrombosis, a rare but potentially fatal phenomenon associated with both congenital and acquired risk factors. Multiple case reports implicate the role of protamine in the development of such thromboses. The role of protamine in facilitating the regulation of hemostasis by reversing the anticoagulant effects of heparin in patients undergoing cardiopulmonary bypass is well-recognized. However, discussion of its potential contribution to coronary graft thrombosis and mechanisms by which this may occur is lacking. Furthermore, its narrow therapeutic index and side effect profile are such that its appropriateness as a universal reversal agent to heparin requires reconsideration. This article reviews the current body of evidence regarding the use of protamine in cardiac surgery and the limited case reports pertaining to its potential role in the pathophysiology of coronary graft thrombosis.

Thrombocytosis and neutrophilia associated with oxygenator failure and protamine reaction after cardiopulmonary bypass: a case report and literature review.

Thrombocytosis has been feared as a source of thrombotic complications during the conduct of cardiopulmonary bypass (CPB) for patients undergoing cardiac procedures. We present a patient urgently requiring repair/replacement of three heart valves that had preexisting myelofibrosis with thrombocytosis (platelet count of 800,000 per µl) and neutrophilia (40,000 per µl). Despite achieving an activated clotting time > 500 s with heparin and antithrombin concentrate administration prior to CPB, the pump oxygenator and reservoir demonstrated significant clot just prior to restoration of the patient's circulation. The patient subsequently suffered a severe protamine reaction that was successfully managed. A review of the literature of similar patients and the relevant cellular and biochemical mechanisms in this setting are presented, with potential therapeutic approaches to prevent such complications noted.

Optimal protamine dosing after cardiopulmonary bypass: The PRODOSE adaptive randomised controlled trial.

BACKGROUND: The dose of protamine required following cardiopulmonary bypass (CPB) is often determined by the dose of heparin required pre-CPB, expressed as a fixed ratio. Dosing based on mathematical models of heparin clearance is postulated to improve protamine dosing precision and coagulation. We hypothesised that protamine dosing based on a 2-compartment model would improve thromboelastography (TEG) parameters and reduce the dose of protamine administered, relative to a fixed ratio. METHODS AND FINDINGS: We undertook a 2-stage, adaptive randomised controlled trial, allocating 228 participants to receive protamine dosed according to a mathematical model of heparin clearance or a fixed ratio of 1 mg of protamine for every 100 IU of heparin required to establish anticoagulation pre-CPB. A planned, blinded interim analysis was undertaken after the recruitment of 50% of the study cohort. Following this, the randomisation ratio was adapted from 1:1 to 1:1.33 to increase recruitment to the superior arm while maintaining study power. At the conclusion of trial recruitment, we had randomised 121 patients to the intervention arm and 107 patients to the control arm. The primary endpoint was kaolin TEG r-time measured 3 minutes after protamine administration at the end of CPB. Secondary endpoints included ratio of kaolin TEG r-time pre-CPB to the same metric following protamine administration, requirement for allogeneic red cell transfusion, intercostal catheter drainage at 4 hours postoperatively, and the requirement for reoperation due to bleeding. The trial was listed on a clinical trial registry (ClinicalTrials.gov Identifier: NCT03532594). Participants were recruited between April 2018 and August 2019. Those in the intervention/model group had a shorter mean kaolin r-time (6.58 [SD 2.50] vs. 8.08 [SD 3.98] minutes; p = 0.0016) post-CPB. The post-protamine thromboelastogram of the model group was closer to pre-CPB parameters (median pre-CPB to post-protamine kaolin r-time ratio 0.96 [IQR 0.78-1.14] vs. 0.75 [IQR 0.57-0.99]; p < 0.001). We found no evidence of a difference in median mediastinal/pleural drainage at 4 hours postoperatively (140 [IQR 75-245] vs. 135 [IQR 94-222] mL; p = 0.85) or requirement (as a binary outcome) for packed red blood cell transfusion at 24 hours postoperatively (19 [15.8%] vs. 14 [13.1%] p = 0.69). Those in the model group had a lower median protamine dose (180 [IQR 160-210] vs. 280 [IQR 250-300] mg; p < 0.001). Important limitations of this study include an unblinded design and lack of generalisability to certain populations deliberately excluded from the study (specifically children, patients with a total body weight >120 kg, and patients requiring therapeutic hypothermia to <28°C). CONCLUSIONS: Using a mathematical model to guide protamine dosing in patients following CPB improved TEG r-time and reduced the dose administered relative to a fixed ratio. No differences were detected in postoperative mediastinal/pleural drainage or red blood cell transfusion requirement in our cohort of low-risk patients. TRIAL REGISTRATION: ClinicalTrials.gov Unique identifier NCT03532594.