In vitro comparison of spatiotemporal fibrin clot formation dynamics in plasma treated with different protamine-heparin ratios.

INTRODUCTION: Our study aim was to explore how different protamine-heparin ratios impacted enzymatic coagulation and acellular fibrin clot growth in plasma using an in vitro model. We hypothesized that a low protamine-heparin ratio would be associated with superior fibrin clot growth dynamics. METHODS: We performed an in vitro study using 15 plasma samples from a commercial supplier. Different protamine-heparin ratios were added to each donor plasma sample: low ratio (0.7-1), traditional ratio (1-1), and high ratio (1.3-1) and clot formation dynamics were evaluated using a Thrombodynamics analyzer. Study outcomes were initial clot growth velocity and clot size at 30 min. RESULTS: Plasma samples treated with a one-to-one protamine-heparin ratio had significantly lower mean initial clot growth velocity compared to samples treated with a low protamine-heparin ratio; mean difference -2.3 µm/min (95% CI = -4.0 to -0.7, p = .004). Plasma samples treated with a one-to-one protamine-heparin ratio also had significantly smaller mean clot size at 30 min compared to samples treated with a low protamine-heparin ratio; mean difference -54.0 µm (95% CI = -107.6 to -0.4, p = .048). There were no significant differences in mean initial clot growth velocity or clot size at 30 min between plasma samples treated with a high protamine-heparin ratio and those treated with a one-to-one or low protamine-heparin ratio (all p > .05). CONCLUSIONS: Plasma samples treated with a low protamine-heparin ratio had superior clot growth velocity and larger clot size at 30 min compared to a one-to-one ratio, supporting the notion that a low protamine-heparin ratio may optimize enzymatic coagulation after cardiopulmonary bypass.

Compromiso cardíaco en el síndrome inflamatorio multisistémico post SARS-CoV-2 en niños / Cardiac involvement in post-SARS-CoV-2 multisystem inflammatory syndrome in children / Envolvimento cardíaco na síndrome inflamatória multissistêmica pós-SARS-CoV-2 em crianças

Objetivo: describir las características de ocho pacientes pediátricos que se presentaron con síndrome inflamatorio multisistémico (MIS-C) asociado a SARS-CoV-2 y compromiso cardíaco. Material y métodos: estudio descriptivo, retrospectivo de ocho pacientes con edades entre 1 y 13 años, con diagnóstico de MIS-C y compromiso cardíaco, asistidos en el CHPR. Se analiza su historia clínica, evolución y tratamiento. Resultados: los pacientes presentaron fiebre en el 100%, exantema e hiperemia conjuntival en el 88%, síntomas digestivos en el 50%, insuficiencia respiratoria en el 25% y shock en el 50%. Todos requirieron ingreso a cuidados intensivos. La alteración de la contractilidad cardíaca estuvo presente en el 63% de los pacientes, fue leve y segmentaria en el 80%, el 60% requirió soporte inotrópico por 3 días, recuperando una función normal en 7 días. La insuficiencia mitral se presentó en el 25% y el derrame pericárdico en el 38%, ambos de grado leve. Un paciente presentó dilatación de arterias coronarias con Z score < 2. El 85% de los pacientes presentó alteraciones del ECG, en el 29% se trató de alteración en la repolarización, en el 29% intervalo QTc prolongado, en el 15% bloqueo atrioventricular de 1er grado y bloqueo incompleto de rama derecha. Un paciente tuvo fibrilación auricular por 3 días con remisión espontánea a ritmo sinusal. Las troponinas estuvieron altas en el 57% de los pacientes y el ProBNP elevado en el 100%. Todos recibieron inmunoglobulinas, metilprednisolona y aspirina. Conclusiones: se presentaron ocho pacientes pediátricos con MIS-C y compromiso cardíaco, el 50% se presentó en shock, todos requirieron ingreso a cuidados intensivos. El 85% presento alteraciones en el ECG. El 63% presentó compromiso de la contractilidad sectorial y leve, se normalizó en 7 días. El 60% requirió soporte inotrópico por una media de 3 días.

Objective: describe the characteristics of 8 children who presented Multisystem Inflammatory Syndrome associated with SARS-CoV2 infections (MIS-C) and cardiac involvement. Material and methods: descriptive, retrospective study of 8 patients of between 1 and 13 years of age, diagnosed with MIS-C and cardiac involvement, assisted at the Pereira Rossell Children Hospital, analysis of their medical records, evolution and treatment. Results: the patients showed: fever in 100% of the cases, rash and conjunctival hyperemia in 88%, digestive symptoms in 50%, respiratory failure in 25% and shock in 50%. All required admission to Intensive Care. Cardiac contractility alteration was present in 63% of patients, the affectation was mild and segmental in 80%, 60% required inotropic support for 3 days and recovered normal functions in 7 days. Mitral regurgitation was present in 25% of the cases and pericardial effusion in 38%, mild in both cases. One patient had dilated coronary arteries with a Z score <2. 85% of the patients presented ECG abnormalities, 29% present alteration of repolarization, 29% prolonged QTc, 15% 1st degree atrioventricular block and incomplete right bundle branch block. One patient had atrial fibrillation for 3 days with spontaneous remission to sinus rhythm. Troponins were increased in 57% of the patients and ProBNP elevated in 100%. All patients received Immunoglobulins, Methylprednisolone and Aspirin. Conclusions: we present eight pediatric patients with MIS-C and cardiac involvement, 50% suffered shock, all required admission to Intensive Care. ECG abnormalities were found in 85% of the patients. Mild and segmental contractility compromise was found in 63% of the patients and normalized in 7 days. 60% required inotropic support for a mean of 3 days.

Objetivo: descrever as características de 8 pacientes pediátricos que apresentaram Síndrome Inflamatória Multissistêmica (MIS-C) associada ao SARS-CoV-2 e comprometimento cardíaco. Material e métodos: estudo descritivo, retrospectivo, de oito pacientes com idade entre 1 e 13 anos, com diagnóstico de MIS-C e comprometimento cardíaco, assistidos pelo CHPR. Seu prontuário médico, evolução e tratamento são analisados. Resultados: os pacientes apresentaram febre em 100%, erupção cutânea e hiperemia conjuntival em 88%, sintomas digestivos em 50%, insuficiência respiratória em 25% e choque em 50%. Todos necessitaram de internação nos cuidados intensivos. A alteração da contratilidade cardíaca esteve presente em 63% dos pacientes, foi leve e segmentar em 80%, 60% necessitaram de suporte inotrópico por 3 dias, recuperando a função normal em 7 dias. A regurgitação mitral ocorreu em 25% dos pacientes e o derrame pericárdico em 38%, ambos de grau leve. Um paciente apresentou dilatação da artéria coronária com escore Z < 2. 85% dos pacientes apresentaram anormalidades no ECG, 29% foram alterações de repolarização, 29% intervalo QTc prolongado em bloqueio atrioventricular de 1º grau a 15% e bloqueio incompleto do ramo direito. Um paciente apresentou fibrilação atrial por 3 dias com remissão espontânea ao ritmo sinusal. As troponinas foram elevadas em 57% dos doentes e ProBNP elevado em 100%. Todos receberam imunoglobulinas, Metilprednisolona e aspirina. Conclusões: houve oito pacientes pediátricos com SMIM-C e comprometimento cardíaco, 50% em choque, todos necessitaram de internação em terapia intensiva. 85% apresentaram elevações no ECG. 63% apresentaram comprometimento setorial e de contratilidade leve, normalizados em 7 dias. 60% necessitaram de suporte inotrópico por uma média de 3 dias.

Reversal Activity and Toxicity of Heparin-Binding Copolymer after Subcutaneous Administration of Enoxaparin in Mice.

Uncontrolled bleeding after enoxaparin (ENX) is rare but may be life-threatening. The only registered antidote for ENX, protamine sulfate (PS), has 60% efficacy and can cause severe adverse side effects. We developed a diblock copolymer, heparin-binding copolymer (HBC), that reverses intravenously administered heparins. Here, we focused on the HBC inhibitory activity against subcutaneously administered ENX in healthy mice. BALB/c mice were subcutaneously injected with ENX at the dose of 5 mg/kg. After 110 min, vehicle, HBC (6.25 and 12.5 mg/kg), or PS (5 and 10 mg/kg) were administered into the tail vein. The blood was collected after 3, 10, 60, 120, 360, and 600 min after vehicle, HBC, or PS administration. The activities of antifactors Xa and IIa and biochemical parameters were measured. The main organs were collected for histological analysis. HBC at the lower dose reversed the effect of ENX on antifactor Xa activity for 10 min after antidote administration, whereas at the higher dose, HBC reversed the effect on antifactor Xa activity throughout the course of the experiment. Both doses of HBC completely reversed the effect of ENX on antifactor IIa activity. PS did not reverse antifactor Xa activity and partially reversed antifactor IIa activity. HBC modulated biochemical parameters. Histopathological analysis showed changes in the liver, lungs, and spleen of mice treated with HBC and in the lungs and heart of mice treated with PS. HBC administered in an appropriate dose might be an efficient substitute for PS to reverse significantly increased anticoagulant activity that may be connected with major bleeding in patients receiving ENX subcutaneously.

Transit time flow measurement of coronary bypass grafts before and after protamine administration.

BACKGROUND: Intraoperative graft assessment with tools like Transit Time Flow Measurement (TTFM) is imperative for quality control in coronary surgery. We investigated the variation of TTFM parameters before and after protamine administration to identify new benchmark parameters for graft quality assessment. METHODS: The database of the REQUEST ("REgistry for QUality AssESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery") study was retrospectively reviewed. A per graft analysis was performed. Only single grafts (i.e., no sequential nor composite grafts) where both pre- and post-protamine TTFM values were recorded with an acoustical coupling index > 30% were included. Grafts with incomplete data and mixed grafts (arterio-venous) were excluded. A second analysis was performed including single grafts only in the same MAP range pre- and post- protamine administration. RESULTS: After adjusting for MAP, we found a small increase in MGF (29 mL/min to 30 mL/min, p = 0.009) and decrease in PI (2.3 to 2.2, p <  0.001) were observed after the administration of protamine. These changes were especially notable for venous conduits and for CABG procedures performed on-pump. CONCLUSION: The small changes in TTFM parameters observed before and after protamine administration seem to be clinically irrelevant, despite being statistically significant in aggregate. Our data do not support a need to perform TTFM measurements both before and after protamine administration. A single TTFM measurement taken either before or after protamine may suffice to achieve reliable data on each graft's performance. Depending on the specific clinical situation and intraoperative changes, more measurements may be informative. TRIAL REGISTRATION: Clinical Trials Number: NCT02385344 , registered February 17th, 2015.

Andexanet Alfa, the Possible Alternative to Protamine for Reversal of Unfractionated Heparin.

The recent shortage of protamine prompted an investigation of alternatives for reversal of unfractionated heparin. Heparin is an anticoagulant utilized in the hospital setting. Available options for anticoagulation include direct oral anticoagulants, vitamin K antagonists, thrombin inhibitors, low-molecular-weight heparins, and heparin. Protamine is the approved reversal agent for heparin with few alternatives under investigation. Although andexanet was designed as an antidote for apixaban and rivaroxaban, in vitro studies show that in a dose-dependent technique, andexanet had near full reversal of heparin, reversed anti-factor Xa activity, and neutralized anticoagulant effects of activated partial thromboplastin time and thrombin time induced by heparin.

Protamine use in transfemoral carotid artery stenting is not associated with an increased risk of thromboembolic events.

BACKGROUND: Protamine use in carotid endarterectomy has been shown to be associated with fewer perioperative bleeding complications without higher rates of thromboembolic events. However, the effect of protamine use on complications after transfemoral carotid artery stenting (CAS) is unclear, and concerns remain about thromboembolic events. METHODS: A retrospective review was performed for patients undergoing transfemoral CAS in the Vascular Quality Initiative from March 2005 to December 2018. We assessed in-hospital outcomes using propensity score-matched cohorts of patients who did and did not receive protamine. The primary outcome was in-hospital stroke or death. Secondary outcomes included bleeding complications, stroke, death, transient ischemic attack, myocardial infarction, and congestive heart failure exacerbation. Bleeding complications were categorized as bleeding resulting in intervention or blood transfusions. RESULTS: Of the 17,429 patients undergoing transfemoral CAS, 2697 (15%) patients received protamine. We created 2300 propensity score-matched pairs of patients who did and did not receive protamine. There were no statistically significant differences in stroke or death between the two cohorts (protamine, 2.5%; no protamine, 2.9%; relative risk [RR], 0.85; 95% confidence interval [CI], 0.60-1.21; P = .37). Protamine use was not associated with statistically significant differences in perioperative bleeding complications resulting in interventional treatment (0.9% vs 0.5%; RR, 2.10; 95% CI, 0.99-4.46; P = .05) or blood transfusion (1.2% vs 1.2%; RR, 0.92; 95% CI, 0.53-1.61; P = .78). There were also no statistically significant differences for the individual outcomes of stroke (1.8% vs 2.3%; RR, 0.78; 95% CI, 0.52-1.16; P = .22), death (0.9% vs 0.8%; RR, 1.17; 95% CI, 0.62-2.19; P = .63), transient ischemic attack (1.4% vs 1.3%; RR, 1.10; 95% CI, 0.67-1.82; P = .70), myocardial infarction (0.5% vs 0.4%; RR, 1.20; 95% CI, 0.52-2.78; P = .67), or heart failure exacerbation (1.0% vs 0.9%; RR, 1.05; 95% CI, 0.58-1.90; P = .88). Protamine use in patients presenting with symptomatic carotid stenosis was associated with lower risk of stroke or death (3.0% vs 4.3%; RR, 0.69; 95% CI, 0.47-0.998; P = .048), whereas there were no statistically significant differences in stroke or death with protamine use in asymptomatic patients (1.6% vs 1.0%; RR, 1.63; 95% CI, 0.67-3.92; P = .28). CONCLUSIONS: Heparin reversal with protamine after transfemoral CAS is not associated with an increased risk of thromboembolic events, and its use in symptomatic carotid disease is associated with a lower risk of stroke or death.

Increased Plasma Heparanase Activity in COVID-19 Patients.

Reports suggest a role of endothelial dysfunction and loss of endothelial barrier function in COVID-19. It is well established that the endothelial glycocalyx-degrading enzyme heparanase contributes to vascular leakage and inflammation. Low molecular weight heparins (LMWH) serve as an inhibitor of heparanase. We hypothesize that heparanase contributes to the pathogenesis of COVID-19, and that heparanase may be inhibited by LMWH. To test this hypothesis, heparanase activity and heparan sulfate levels were measured in plasma of healthy controls (n = 10) and COVID-19 patients (n = 48). Plasma heparanase activity and heparan sulfate levels were significantly elevated in COVID-19 patients. Heparanase activity was associated with disease severity including the need for intensive care, lactate dehydrogenase levels, and creatinine levels. Use of prophylactic LMWH in non-ICU patients was associated with a reduced heparanase activity. Since there is no other clinically applied heparanase inhibitor currently available, therapeutic treatment of COVID-19 patients with low molecular weight heparins should be explored.

Editor's Choice - Protamine Reduces Serious Bleeding Complications Associated with Carotid Endarterectomy in Asymptomatic Patients without Increasing the Risk of Stroke, Myocardial Infarction, or Death in a Large National Analysis.

OBJECTIVE: Controversy persists regarding the use of protamine during carotid endarterectomy (CEA), despite real world evidence to support its use. The purpose of this study was to determine the impact of protamine reversal of heparin anticoagulation on the outcome of CEA in the USA. METHODS: A prospective national registry (Society for Vascular Surgery Vascular Quality Initiative) of 72 787 patients undergoing elective asymptomatic CEA by 1879 surgeons from 316 centres in the USA and Canada from 2012 to 2018 was reviewed. Protamine use varied by both surgeon (20% rare use [< 10%], 30% variable use [11%-79%], 50% routine use [> 80% cases]) and geographical region (44% vs. 96%). Temporal trends in protamine use were also determined. End points included post-operative re-operation for bleeding, as well as potential protamine related thrombotic complications, including stroke, death, and myocardial infarction (MI). Predictors of end points were determined by multivariable logistic regression. Propensity matching was additionally used to control for differences between groups. RESULTS: Of the 72 787 patients who underwent CEA, 69% received protamine, while 31% did not. Protamine use increased over time from 60% (2012) to 73% (2018). In total, 378 patients (0.7%) in the protamine treated group underwent re-operation for bleeding vs. 342 patients (1.4%) in the untreated cohort (p < .001). Protamine use did not affect the rate of MI (0.7% vs. 0.8%; p = .023), stroke (1.1% vs. 1.0%; p = .20), or in hospital death (0.2% vs. 0.2%; p = 0.70) between treated and untreated patients, respectively. On multivariable analysis, protamine use was independently associated with reduced risk of re-operation for bleeding (odds ratio 0.5, 95% confidence interval 0.39-0.55; p < .001). Independent of protamine exposure, the consequences of a return to the operating room (RTOR) for bleeding were statistically significant, with a sevenfold increase in MI (RTOR 4.9% vs. no RTOR 0.7%; p < .001), an eightfold increase in stroke (RTOR 7.2% vs. no RTOR 0.9%; p < .001), and a 13 fold increase in death (RTOR 2.4% vs. no RTOR 0.2%; p < .001). CONCLUSION: Protamine reduces serious bleeding complications at the time of CEA without increasing the risk of MI, stroke, or death, in this large North American analysis. Based on this and previous regional work regarding protamine use in CEA, it is believed that there is now sufficient evidence to support its routine use, and it should be considered as a benchmark for quality during CEA.

Mid-term Clinical Outcomes of Immediate Protamine Use Following Elective Percutaneous Coronary Interventions.

Bleeding complication has been considered as a serious problem in current percutaneous coronary interventions (PCI). Fortunately, several groups have already reported the effectiveness of protamine use just after PCI to immediately remove any arterial sheath. However, there is a concern that protamine reversal may increase non-occlusive thrombus and, in turn, lead to mid-term cardiovascular events such as target vessel revascularization (TVR) or stent thrombosis. Thus, the purpose of this study was to evaluate whether protamine use following elective PCI was associated with mid-term clinical outcomes. In total, 472 patients were included in this study; subsequently, they were divided into protamine group (n = 142) and non-protamine group (n = 330). The primary endpoint was the composite of ischemia-driven TVR and stent thrombosis. The median follow-up period was determined to be at 562 days. In total, 32 primary endpoints were observed during the study period, and the incidence of primary endpoints tended to be greater in the protamine group than in the non-protamine group (P = 0.056). However, the lesion length, the degree of calcification, and the prevalence of hemodialysis were significantly determined greater in the protamine group than in the non-protamine group. In the multivariate Cox proportional hazards model, the use of protamine (versus non-protamine: hazard ratio 0.542 and 95% confidence interval 0.217-1.355, P = 0.191) was deemed not to be associated with the primary endpoint after controlling legion length, calcification, and hemodialysis. In conclusion, immediate protamine use following elective PCI did not increase mid-term ischemia-driven TVR or stent thrombosis. However, immediate protamine use after PCI should be discussed further for the safety of the patient.

Protamine use in transcarotid artery revascularization is associated with lower risk of bleeding complications without higher risk of thromboembolic events.

OBJECTIVE: Recent studies have found that transcarotid artery revascularization (TCAR) is associated with lower risk of stroke or death compared with transfemoral carotid artery stenting but higher risk of bleeding complications, presumably associated with the need for an incision. Heparin anticoagulation is universally used during TCAR, so protamine use may reduce bleeding complications. However, the safety and effectiveness of protamine use in TCAR are unknown. We therefore evaluated the impact of protamine use on perioperative outcomes after TCAR in the Vascular Quality Initiative TCAR Surveillance Project. METHODS: We performed a retrospective review of patients undergoing TCAR in the Vascular Quality Initiative TCAR Surveillance Project from September 2016 to April 2019. We assessed in-hospital outcomes using propensity score-matched cohorts of patients who did and did not receive protamine. The primary efficacy end point was access site bleeding complications, and the primary safety end point was in-hospital stroke or death. Secondary end points included the individual end points of stroke, death, transient ischemic attack, myocardial infarction, congestive heart failure exacerbation, and hemodynamic instability. RESULTS: Of the 5144 patients undergoing TCAR, all patients received heparin and 4072 (79%) patients received protamine. We identified 944 matched pairs of patients who did and did not receive protamine. Protamine use was associated with a significantly lower risk of bleeding complications (2.8% vs 8.3%; relative risk [RR], 0.33; 95% confidence interval [CI], 0.21-0.52; P < .001), including bleeding that resulted in interventional treatment (1.0% vs 3.6%; RR, 0.26; 95% CI, 0.13-0.54; P < .001) and in blood transfusion (1.2% vs 3.9%; RR, 0.30; 95% CI, 0.15-0.58; P <.001). There were no statistically significant differences in in-hospital stroke or death for patients who received protamine and those who did not (1.6% vs 2.2%; RR, 0.71; 95% CI, 0.37-1.39; P = .32); however, there was a trend toward lower risk of stroke for patients who received protamine (1.1% vs 2.0%; RR, 0.53; 95% CI, 0.24-1.13; P = .09). There were also no statistically significant differences in the rates of transient ischemic attack (0.4% vs 1.1%; RR, 0.40; 95% CI, 0.13-1.28; P = .11), myocardial infarction (0.4% vs 0.8%; RR, 0.50; 95% CI, 0.15-1.66; P = .25), heart failure exacerbation (0.4% vs 0.3%; RR, 1.33; 95% CI, 0.30-5.96; P = .71), or postoperative hypotensive hemodynamic instability (16% vs 15%; RR, 1.06; 95% CI, 0.83-1.35; P = .50) with protamine use. CONCLUSIONS: Protamine can be safely used in TCAR to reduce the risk of perioperative bleeding complications without increasing the risk of thrombotic events.

Timing of Anticoagulation in Patients with Cerebral Venous Thrombosis Requiring Decompressive Surgery: Systematic Review of the Literature and Case Series.

OBJECTIVE: Cerebral venous thrombosis (CVT) is a rare type of stroke whose pathophysiology differs from arterial stroke. CVT is treated with systemic anticoagulant therapy even in the setting of intracerebral hemorrhage. Patients who do not respond adequately may require decompressive surgery. The study objective was to examine the timing of anticoagulation in patients with CVT who require decompressive surgery through systematic literature review and consecutive case series. METHODS: A review of the literature was performed through PubMed using key word search to identify case series and cohort studies examining timing of anticoagulation following decompressive surgery. Our case series included 4 patients who had decompressive surgery for hemorrhagic CVT between 1 January, 2015 and 31 December, 2016 at our comprehensive stroke center. RESULTS: The literature review summarizes 243 patients from 15 studies whose timing of anticoagulation varied. The review suggests anticoagulation can be safely resumed at 48 hours postoperatively based on larger series and as early as 12 hours in smaller series, especially when delivered as a half or prophylactic dose. In our case series, timing of anticoagulation varied slightly but was started or resumed within 38-44 hours postoperatively in 3 patients and was started at the time of decompressive surgery without interruption in 1 patient. No patient had worsening hemorrhage or new hemorrhage while 2 patients rethrombosed. CONCLUSIONS: Despite the lack of high-quality studies, this systematic review of patients with CVT requiring decompressive surgery indicates that anticoagulation can be safely initiated or resumed around 24-48 hours postoperatively; our series supports the existing literature.

Comparison of international normalized ratio determined by point-of-care to standard laboratory testing before and after reversal of heparin in cardiac surgery.

STUDY OBJECTIVE: To compare point-of-care (POC) of international normalized ratio to laboratory-derived values before and after cardiopulmonary bypass, with the primary aim of evaluating for any change in the relationship between the tests. METHODS: This is a prospective observational study with 50 patients undergoing cardiac surgery enrolled. The International normalized ratio measured at two time points, precardiopulmonary bypass and after heparin reversal with protamine using both POC i-STAT and standard laboratory analysis for both time points. A difference of 0.2 between tests at either time point was considered clinically significant based on previous literature. A paired t test was used to test for a changing or statistically significant mean difference between tests. At both time points values were categorized into absolute difference of more than 0.2 or less than 0.2, and a Fisher's exact test was used to determine if an association existed between heparin reversal and a difference more than 0.2. Bland-Altman plots were also evaluated for agreement. RESULTS: A statistically and clinically significant mean difference [0.09 vs. 0.25, difference -0.163 95% confidence interval (-0.25, -0.08), P = 0.003] was seen between the laboratory and POC tests when pre and postheparin reversal samples were compared. A significantly greater number of patients had a clinically relevant difference between the tests post compared with pre (four patients vs. 18 patients, P = 0.001). Linear regression analysis of the difference compared with the means, showed significant correlation suggesting the presence of a proportional bias (pre r = 0.488, P = <0.01, post r = 0.571, P = <0.01). CONCLUSION: Clinically significant differences exist between POC and laboratory testing of international normalized ratio after heparin reversal during cardiac surgery. ClinicalTrials.gov Identifier NCT03267823.

Heparin reversal with protamine sulfate is not required in atrial fibrillation ablation with suture hemostasis.

BACKGROUND: The utility of protamine sulfate for heparin reversal in catheter-based atrial fibrillation (AF) ablation is unclear when using the suture closure technique for vascular hemostasis. OBJECTIVE: This study sought to address if protamine sulfate use for heparin reversal reduces vascular access complications in AF catheter ablation when suture techniques are used for postprocedural vascular hemostasis. METHODS: This is a retrospective multicenter observational study of 294 consecutive patients who underwent catheter ablation for AF with subsequent vascular access hemostasis by means of a figure-of-eight suture or stopcock technique. A total of 156 patients received protamine for heparin reversal before sheath removal while 138 patients did not receive protamine. The two groups were compared for procedural activated clotting time (ACT), access site complications, and duration of hospital stay. RESULTS: Baseline demographic characteristics were comparable in both groups. Despite higher ACT before venous sheath removal in patients not receiving protamine (288.0 ± 44.3 vs 153.9 ± 32.0 seconds; P < .001), there was no significant difference in groin complications, postoperative thromboembolic events, or duration of hospital stay between the two groups. Suture failure requiring manual compression was rarely observed in this cohort (0.34%). CONCLUSION: With modern vascular access and sheath management techniques, for patients undergoing catheter ablation for AF, simple suture closure techniques can obviate the need for protamine administration to safely achieve hemostasis after removal of vascular sheaths.

Detection of early incomplete heparin reversal following congenital cardiac surgery: A single-center retrospective observational study.

BACKGROUND: The monitoring of unfractionated heparin (UFH) reversal with protamine plays a crucial role for bleeding management after cardio-pulmonary bypass (CPB) in congenital cardiac surgery. The current standard for the monitoring of UFH and its reversal is the activated clotting time (ACT). While the ACT is affected by other CPB-associated pathologies a bedside technique with more specific heparin-related results would be very helpful. The new point-of-care viscoelastic test Haemonetics TEG® 6s, which is based on small blood samples may fulfill these requirements. This study aimed to compare the new TEG with laboratory assays. METHODS: A retrospective observational study was performed on 40 children with a median age of 130 days (interquartile range 13 to 310 days) undergoing congenital cardiac surgery. After separation of CPB, test results of the TEG® 6s, ACT, anti-Xa for UFH and PTT were compared and correlated with each other. RESULTS: No clinically relevant correlation was found for heparin specific TEG-derived parameters (CK/CKH R-time ratio) with ACT, PTT and anti-Xa measurements. After grouping in dependence to the CK/CKH R-time in patients with and without successful heparin reversal again no significant difference of anti-Xa-UFH-levels, post-/pre-CPB ratio of the PTT and ACT was observed. CONCLUSIONS: In pediatric patients undergoing cardiac surgery using CPB there is no association of conventional coagulation tests and TEG-derived results. While bedside viscoelastic tests deliver rapid results, further studies are needed to compare whether the TEG based management of incomplete heparin reversal is sufficient to monitor heparin reversal and to reduce blood loss.

Thrombolysis Following Heparin Reversal With Protamine Sulfate in Acute Ischemic Stroke: Case Series and Literature Review.

INTRODUCTION: Administering intravenous IV tissue plasminogen activator (tPA) is the recommended standard of care in acute ischemic stroke (AIS), although it is not recommended to administer intravenous thrombolysis with tPA following heparin reversal with protamine sulfate in patients with AIS. METHODS: We describe a case series of three patients and the most comprehensive literature review published to date in this specific subset of AIS patients undergoing thrombolysis following heparin reversal with protamine sulfate. The literature review was based on a scoping review methodology performed on four databases; PubMed, CINAHL, Web of Science, and Cochrane Library. All sources were searched from the inauguration of the database until February 2019. A total of six articles involving eight patients were identified. RESULTS: The primary safety outcome of no symptomatic intracranial hemorrhage (sICH) was met in all eleven patients, although only seven cases had a good functional outcome at 3 months. CONCLUSIONS: In appropriately selected AIS patients, coagulopathy correction appears to be safe from an sICH standpoint and may be beneficial. However, given the potential for bias with observational databases, case reports and case series, extreme caution is warranted in applying these results to routine clinical practice.

Neck haematoma after carotid endarterectomy: risks, rescue, and prevention.

OBJECTIVE: This study was performed to identify risk factors for neck haematoma requiring re-exploration after carotid endarterectomy. Neck haematoma is a well-known complication after carotid endarterectomy, but there has been little discussion about intraoperative techniques for its prevention. We also investigated an intraoperative neck flexion technique for prevention of neck haematoma. METHODS: A retrospective study reviewed 384 carotid endarterectomies performed at our institution from 2003 to 2016. The endpoint was neck haematomas requiring re-exploration after carotid endarterectomy. Endpoint predictors (general factors, preoperative medication, and intraoperative factors) were identified by univariate analysis. Our intraoperative neck flexion technique involved changing the neck and head position from extension to flexion during carotid endarterectomy. In patients with neck haematoma, we assessed the interval from carotid endarterectomy to re-exploration, the source of bleeding, and the method of airway rescue. RESULTS: There was one major and three minor perioperative strokes (1.1%). Neck haematoma occurred in 9 patients (2.4%). Univariate analysis (odds ratio [95% confidence interval]) identified preoperative clopidogrel therapy (4.19 [1.03-17.06], P = .04) and not using protamine sulfate after heparin (4.13 [1.02-25.06], P = .04) as risk factors for haematoma. We used the intraoperative neck flexion technique in 87 patients and no neck haematomas occurred. There was no additional morbidity and no mortality in the patients who required re-exploration. The interval between carotid endarterectomy and re-exploration ranged from 0 to 30 hours. Intubation before re-exploration was often difficult. We recommend using a laryngeal mask and performing minor wound re-exploration under local anesthesia before tracheal intubation for general anesthesia. Haematomas were mainly caused by venous bleeding or capillary oozing. CONCLUSIONS: This study showed that neck haematoma is uncommon after carotid endarterectomy, but requires emergency airway rescue and re-exploration.

Protamine sulfate for the reversal of enoxaparin associated hemorrhage beyond 12 h.

Clinical practice guidelines recommend protamine sulfate for reversal of enoxaparin associated bleeds dependent on the time from last administration and dose of enoxaparin. We present a case of a hemodynamically unstable patient with an enoxaparin induced abdominal wall hematoma/hemorrhage and the previous enoxaparin administration 21.5 h prior to presentation with a therapeutic anti-Xa assay (0.8 IU/mL) upon assessment in the emergency department. Along with resuscitative efforts, an interdisciplinary team collaborated to administer protamine sulfate 50 mg intravenous once (0.5 mg per 1 mg of enoxaparin) to reverse the therapeutic anticoagulation. Our case demonstrates the importance of monitoring renal function and the potential for accumulation of enoxaparin in patients with renal dysfunction leading to prolonged therapeutic anti-Xa assays. With the availability of anti-Xa assays, future reversal recommendations of enoxaparin associated bleeds using protamine sulfate should include the initial anti-Xa assay as a guide for the dosing regimen.

Thrombolysis After Protamine Reversal of Heparin for Acute Ischemic Stroke After Cardiac Catheterization: Case Report and Literature Review.

BACKGROUND: Patients with an acute ischemic stroke (AIS) following cardiac catheterization (CC) generally do not receive intravenous thrombolysis [intravenous tissue plasminogen activator (IV-tPA)] as it is contraindicated due to the coagulopathy related to the heparin used during the procedure. We report a case of AIS successfully treated with IV thrombolysis following protamine reversal of heparin effect. CASE REPORT: An 87-year-old man with diabetes mellitus, hypertension, neurofibromatosis, and hyperlipidemia underwent elective transradial CC following an abnormal stress test. He had 2 drug-eluting stents for severe stenosis of mid-circumflex and right coronary arteries and received heparin 13,000 IU during procedure. He developed acute left hemiparesis with initial NIH stroke scale (NIHSS) of 4. Computed tomographic scan of the brain and computed tomographic angiogram of head and neck were unremarkable. Bedside activated clotting time was 181. Protamine 40 mg was administered and 30 minutes later, the activated clotting time level was normalized. IV-tPA was administered at 4 hours 25 minutes from his last known well. Within 15 minutes, his NIHSS was 0. Magnetic resonance imaging of brain showed no acute infarction 24 hours after stroke. CONCLUSIONS: There are limited reports of protamine reversal of heparin before IV-tPA administration. To our knowledge, there are only 6 AIS cases including ours. Three cases received 0.6 mg/kg of tPA dose. All have favorable outcomes and no intracranial hemorrhage was reported. Protamine reversal of heparin for AIS after CC seems to be safe. Further studies are needed to confirm the therapeutic safety and efficacy of this strategy.

Safety of Reversing Anticoagulation by Protamine Following Elective Transfemoral Percutaneous Coronary Intervention in the Drug-Eluting Stent Era.

Bleeding complications following percutaneous coronary interventions (PCI) have been closely associated with morbidity and mortality. Although radial arteries have been widely used in current PCI, including primary PCI, transfemoral PCI remains necessary for complex PCI. The purpose of this study was to compare the incidence of complications following elective transfemoral PCI between manual compression with and without protamine. We identified 249 consecutive patients who underwent elective transfemoral PCI from hospital records, and divided them into two groups: patients who used protamine for manual compression (the protamine group; n = 205) and patients who did not (the non-protamine group, n = 44). Complications including acute thrombosis, bleeding requiring blood transfusion, transient hypotension, skin rash, and death within 30 days were compared between groups. The baseline clinical and procedural characteristics were comparable between the protamine and non-protamine groups. The incidences of all complications were not different between the protamine (5.9%) and the non-protamine groups (9.1%) (P = 0.43). While more than 90% of the patients received drug-eluting stent implantation, there was no acute thrombus in either group. The incidence of bleeding requiring blood transfusion was significantly lower in the protamine group (0.5%) than in the non-protamine group (6.8%) (P = 0.002). Multivariate logistic regression analysis revealed the inverse association between protamine use and bleeding requiring blood transfusion (odds ratio 0.08, 95% confidence interval 0.01-0.84, P = 0.04). In conclusion, the use of protamine for manual compression following elective transfemoral PCI was safe and was associated with less bleeding complications.