Recombinant Activated Factor VII (rFVIIa) for Bleeding After Thoracic Aortic Surgery: A Scoping Review of Current Literature

BACKGROUND

Bleeding after surgery on the thoracic aorta is a frequent complication, and can be associated with a significant increase in morbidity and mortality. Recombinant activated factor VII (rFVIIa) was developed initially for treating patients with hemophilia; however, it has been used increasingly "off-label" to achieve hemostasis after thoracic aortic procedures.

OBJECTIVE

This scoping review aimed to present the available literature on the role of rFVIIa in the management of refractory postoperative bleeding after thoracic aortic surgery.

METHODS/RESULTS

An electronic database search was conducted using Medline, Embase, Cochrane Library, and Google Scholar in June 2023. The authors included studies that reported the use of rFVIIa in patients undergoing surgical repair of ascending or descending aortic aneurysm or dissection. Single-case reports were excluded. Ten publications with a pooled number of 649 patients (319 patients received rFVIIa and 330 in the control groups) were identified: 3 case series, 6 retrospective studies, and 1 nonrandomized clinical trial. All studies reported the potential role of rFVIIa in correcting coagulopathy and reducing postoperative blood loss in this group of patients. Overall, there was not enough evidence to suggest that rFVIIa was associated with higher rates of thromboembolic complications or mortality.

CONCLUSION

Limited evidence suggests that rFVIIa may be useful in managing postoperative refractory bleeding in patients undergoing thoracic aortic surgery. However, the impact of rFVIIa on thromboembolic complications and mortality rates remains unclear.

Effect of cardiopulmonary bypass on coagulation factors II, VII and X in a primate model: an exploratory pilot study

OBJECTIVES

The use of cardiopulmonary bypass (CPB) in cardiac surgery is a major risk factor for postoperative bleeding. We hypothesized that consumptive coagulopathy and haemodilution influence the coagulation factors; therefore, we aimed to estimate the activity profiles of coagulation factors II, VII and X during CPB circulation.

METHODS

A 120-min bypass was surgically established in cynomolgus monkeys (n = 7). Activities of coagulation factors II, VII and X were measured at 6 time points during the experiment (baseline, 0, 30, 60, 120 min of bypass and 60 min after bypass). To assess the influence of consumptive coagulopathy, the values were adjusted for haemodilution using the haematocrit values. Data were expressed as mean (standard deviation).

RESULTS

Activities of coagulation factors decreased during the experiment. In particular, the activities for II, VII and X were decreased the most by 44.2% (5.0), 61.4% (4.3) and 49.0% (3.7) at 30 min following CPB initiation (P < 0.001, P < 0.001 and P < 0.001, respectively). Following adjustments for haemodilution, change magnitudes lessened but remained significant for factor VII. The adjusted concentration of factor VII was observed to decrease from the baseline to the initiation of bypass circulation.

CONCLUSIONS

In conclusion, coagulation factor II, VII and X concentrations decreased during CPB. Following adjustment for haemodilution, a decrease in concentration was observed with factor VII.

Cold-stored platelets for acute bleeding in cardiac surgical patients: a narrative review

PURPOSE

Cold-stored platelets (CSP) are an increasingly active topic of international research. They are maintained at 1-6 °C, in contrast to standard room-temperature platelets (RTP) kept at 20-24 °C. Recent evidence suggests that CSP have superior hemostatic properties compared with RTP. This narrative review explores the application of CSP in adult cardiac surgery, summarizes the preclinical and clinical evidence for their use, and highlights recent research.

SOURCE

A targeted search of MEDLINE and other databases up to 24 February 2022 was conducted. Search terms combined concepts such as cardiac surgery, blood, platelet, and cold-stored. Searches of trial registries ClinicalTrials.gov and WHO International Clinical Trials Registry Platform were included. Articles were included if they described adult surgical patients as their population of interest and an association between CSP and clinical outcomes. References of included articles were hand searched.

PRINCIPAL FINDINGS

When platelets are stored at 1-6 °C, their metabolic rate is slowed, preserving hemostatic function for increased storage duration. Cold-stored platelets have superior adhesion characteristics under physiologic shear conditions, and similar or superior aggregation responses to physiologic agonists. Cold-stored platelets undergo structural, metabolic, and molecular changes which appear to "prime" them for hemostatic activity. While preliminary, clinical evidence supports the conduct of trials comparing CSP with RTP for patients with platelet-related bleeding, such as those undergoing cardiac surgery.

CONCLUSION

Cold-stored platelets may have several advantages over RTP, including increased hemostatic capacity, extended shelf-life, and reduced risk of bacterial contamination. Large clinical trials are needed to establish their potential role in the treatment of acutely bleeding patients.

Chronological comparison of TAVI and SAVR stratified to surgical risk: a systematic review, meta-analysis, and meta-regression

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has been established as a reasonable alternative to surgical aortic valve replacement (SAVR) in patients with severe aortic stenosis. However, long-term outcomes including valve durability and the need for reintervention are unanswered, especially in younger patients who tend to be low surgical risk. We performed a meta-analysis comparing clinical outcomes after TAVI and SAVR over 5 years stratified to low, intermediate, and high surgical risks.

METHODS

We identified propensity score-matched observational studies and randomised controlled trials comparing TAVI and SAVR. Primary outcomes, including all-cause mortality, moderate or severe aortic regurgitation, moderate or severe paravalvular regurgitation, pacemaker placement, and stroke, were extracted. Meta-analyses of outcomes after TAVI compared to SAVR were conducted for different periods of follow-up. Meta-regression was also performed to analyse the correlation of outcomes over time.

RESULTS

A total of 36 studies consisting of 7 RCTs and 29 propensity score-matched studies were selected. TAVI was associated with higher all-cause mortality at 4-5 years in patients with low or intermediate surgical risk. Meta-regression time demonstrated an increasing trend in the risk of all-cause mortality after TAVI compared with SAVR. TAVI was generally associated with a higher risk of moderate or severe aortic regurgitation, moderate or severe paravalvular regurgitation, and pacemaker placement.

CONCLUSIONS

TAVI demonstrated an increasing trend of all-cause mortality compared with SAVR when evaluated over a long-term follow-up. More long-term data from recent studies using newer-generation valves and state-of-the-art techniques are needed to accurately assign risks.

In vitro study on the effect of fibrinogen γ-chain peptide-coated ADP-encapsulated liposomes on postcardiopulmonary bypass coagulopathy using patient blood

BACKGROUND

Fibrinogen γ-chain peptide-coated, adenosine 5'-diphosphate (ADP)-encapsulated liposomes (H12-ADP-liposomes) are potent hemostatic adjuvants that promote platelet thrombi formation at bleeding sites. Although we have reported the efficacy of these liposomes in a rabbit model of cardiopulmonary bypass coagulopathy, we are yet to address the possibility of their hypercoagulative potential, especially in human beings.

OBJECTIVES

Considering its future clinical applications, we herein investigated the safety of using H12-ADP-liposomes in vitro using blood samples from patients who had received platelet transfusion after cardiopulmonary bypass surgeries.

METHODS

Ten patients receiving platelet transfusions after cardiopulmonary bypass surgery were enrolled. Blood samples were collected at the following 3 points: at the time of incision, at the end of the cardiopulmonary bypass, and immediately after platelet transfusion. After incubating the samples with H12-ADP-liposomes or phosphate-buffered saline (PBS, as a control), blood coagulation, platelet activation, and platelet-leukocyte aggregate formation were evaluated.

RESULTS

Patients' blood incubated with H12-ADP-liposomes did not differ from that incubated with PBS in coagulation ability, degree of platelet activation, and platelet-leukocyte aggregation at any of the time points.

CONCLUSION

H12-ADP-liposomes did not cause abnormal coagulation, platelet activation, or platelet-leukocyte aggregation in the blood of patients who received platelet transfusion after a cardiopulmonary bypass. These results suggest that H12-ADP-liposomes could likely be safely used in these patients, providing hemostasis at the bleeding sites without causing considerable adverse reactions. Future studies are needed to ensure robust safety in human beings.

Outcomes of Heart Transplantation Using a Temperature-controlled Hypothermic Storage System

BACKGROUND

The SherpaPak Cardiac Transport System is a novel technology that provides stable, optimal hypothermic control during organ transport. The objectives of this study were to describe our experience using the SherpaPak system and to compare outcomes after heart transplantation after using SherpaPak versus the conventional static cold storage method (non-SherpaPak).

METHODS

From 2018 to June 2021, 62 SherpaPak and 186 non-SherpaPak patients underwent primary heart transplantation at Stanford University with follow-up through May 2022. The primary end point was all-cause mortality, and secondary end points were postoperative complications. Optimal variable ratio matching, cox proportional hazards regression model, and Kaplan-Meier survival analyses were performed.

RESULTS

Before matching, the SherpaPak versus non-SherpaPak patients were older and received organs with significantly longer total allograft ischemic time. After matching, SherpaPak patients required fewer units of blood product for perioperative transfusion compared with non-SherpaPak patients but otherwise had similar postoperative outcomes such as hospital length of stay, primary graft dysfunction, inotrope score, mechanical circulatory support use, cerebral vascular accident, myocardial infarction, respiratory failure, new renal failure requiring dialysis, postoperative bleeding or tamponade requiring reoperation, infection, and survival.

CONCLUSIONS

In conclusion, this is one of the first retrospective comparison studies that evaluated the outcomes of heart transplantation using organs preserved and transported via the SherpaPak system. Given the excellent outcomes, despite prolonged total allograft ischemic time, it may be reasonable to adopt the SherpaPak system to accept organs from a remote location to further expand the donor pool.

Minimally invasive direct coronary artery bypass and percutaneous coronary intervention followed by transcatheter aortic valve implantation: A promising concept in high-risk octogenarians

Objectives

In this article, we present our initial clinical experience with staged minimally invasive direct coronary bypass (MIDCAB), percutaneous coronary intervention (PCI), and transcatheter aortic valve implantation (TAVI) in high-risk octogenarians (Hybrid).

Background

The use of percutaneous techniques for managing structural heart diseases, especially in elderly high-risk patients, has revolutionized the treatment of structural heart diseases. These procedures are present predominantly being offered as isolated interventions. The feasibility, clinical benefit, and outcomes of combining these techniques with MIDCAB have not been sufficiently explored and have subsequently been underreported in the contemporary literature.

Methods

Four consecutive octogenarians with severe aortic stenosis (AS) and complex coronary artery disease (CAD) that were at high risk for conventional surgery with extracorporeal circulation (ECC) were discussed in our Multidisciplinary Heart Team (MDH). Our MDH consisted of an interventional cardiologist, cardiac surgeon, and cardiac anesthesiologist. A hybrid approach with the alternative strategy comprising of MIDCAB, PCI, and TAVI in a staged fashion was agreed on. All 4 patients had both PCI/stenting and MIDCAB prior to deployment of the TAVI-prosthesis.

Results

From January 2019 to December 2020, 4 consecutive patients aged between 83 and 85 (3 male/1 female) years were scheduled for MIDCAB/PCI followed by percutaneous treatment of severe symptomatic AS. Intraoperatively, one patient was converted to full sternotomy, and surgery was performed by off-pump coronary artery bypass grafting. The overall procedural success rate was 100% in all 4 patients with resolution of their initial presenting cardiopulmonary symptoms. There were no severe complications associated with all hybrid procedures. There was no 30-day mortality in all patients. All patients were discharged home with a median hospital stay ranging between 9 and 25 days. All patients have since then been followed-up regularly. There was one noncardiac-related mortality at 6-months postsurgery. All other patients were well at 1-year follow-up with improved New York Heart Association Class II.

Conclusions

In a selected group of elderly, high prohibitive risk patients with CAD and severe symptomatic AS, a staged approach with MIDCAB and PCI followed by TAVI can be safely performed with excellent outcomes. We advocate a MDH-based preliminary evaluation of this patient cohort in selecting suitable patients and appropriate timing of each stage of the hybrid procedure.

Platelet Function is Preserved After Moderate Cardiopulmonary Bypass Times But Transiently Impaired After Protamine

OBJECTIVES

Previous studies have described impaired platelet function after cardiopulmonary bypass (CPB). Whether this is still valid in contemporary cardiac surgery is unclear. This study aimed to quantify changes in function and number of platelets during CPB in a present-day cardiac surgery cohort.

DESIGN

Prospective, controlled clinical study.

SETTING

A single-center university hospital.

PARTICIPANTS

Thirty-nine patients scheduled for coronary artery bypass graft surgery with CPB.

INTERVENTIONS

Platelet function and numbers were measured at 6 timepoints in 39 patients during and after coronary artery bypass graft surgery; at baseline before anesthesia, at the end of CPB, after protamine administration, at intensive care unit (ICU) arrival, 3 hours after ICU arrival, and on the morning after surgery.

MEASUREMENTS AND MAIN RESULTS

Platelet function was assessed with impedance aggregometry and flow cytometry. Platelet numbers are expressed as actual concentration and as numbers corrected for dilution using hemoglobin as a reference marker. There was no consistent impairment of platelet function during CPB with either impedance aggregometry or flow cytometry. After protamine administration, a decrease in platelet function was seen with impedance aggregometry and for some markers of activation with flow cytometry. Platelet function was restored 3 hours after arrival in the ICU. During CPB (85.0 ± 21 min), the number of circulating platelets corrected for dilution increased from 1.73 ± 0.42 × 10⁹/g to 1.91 ± 0.51 × 10⁹/g (p < 0.001).

CONCLUSIONS

During cardiac surgery with moderate CPB times, platelet function was not impaired, and no consumption of circulating platelets could be detected. Administration of protamine transiently affected platelet function.

Microvascular dysfunction following cardiopulmonary bypass plays a central role in postoperative organ dysfunction

Despite significant advances in surgical technique and strategies for tissue/organ protection, cardiac surgery involving cardiopulmonary bypass is a profound stressor on the human body and is associated with numerous intraoperative and postoperative collateral effects across different tissues and organ systems. Of note, cardiopulmonary bypass has been shown to induce significant alterations in microvascular reactivity. This involves altered myogenic tone, altered microvascular responsiveness to many endogenous vasoactive agonists, and generalized endothelial dysfunction across multiple vascular beds. This review begins with a survey of in vitro studies that examine the cellular mechanisms of microvascular dysfunction following cardiac surgery involving cardiopulmonary bypass, with a focus on endothelial activation, weakened barrier integrity, altered cell surface receptor expression, and changes in the balance between vasoconstrictive and vasodilatory mediators. Microvascular dysfunction in turn influences postoperative organ dysfunction in complex, poorly understood ways. Hence the second part of this review will highlight in vivo studies examining the effects of cardiac surgery on critical organ systems, notably the heart, brain, renal system, and skin/peripheral tissue vasculature. Clinical implications and possible areas for intervention will be discussed throughout the review.

Factor XIII levels, clot strength, and impact of fibrinogen concentrate in infants undergoing cardiopulmonary bypass: a mechanistic sub-study of the FIBCON trial

BACKGROUND

Acquired factor XIII (FXIII) deficiency after major surgery can increase postoperative bleeding. We evaluated FXIII contribution to clot strength and the effect of fibrinogen concentrate administration on FXIII activity in infants undergoing cardiac surgery using cardiopulmonary bypass.

METHODS

We conducted a prospectively planned, mechanistic sub-study, nested within the Fibrinogen Concentrate Supplementation in the Management of Bleeding During Paediatric Cardiopulmonary Bypass: A Phase 1B/2A, Open-Label Dose Escalation Study (FIBCON) trial, which investigated fibrinogen concentrate supplementation during cardiopulmonary bypass (ISRCTN: 50553029) in 111 infants (median age 6.4 months). The relationships between platelet number, fibrinogen concentration, and FXIII activity with rotational thromboelastometry clot strength (EXTEM-MCF) in blood taken immediately before cardiopulmonary bypass and after separation from bypass were estimated using multivariable linear regression. Changes in coagulation variables over time were quantified using a generalised linear model comparing three groups: fibrinogen concentrate-supplemented infants, placebo, and a third cohort with lower bleeding risk.

RESULTS

Overall, 48% of the variability (multivariable R²) in EXTEM-MCF clot strength was explained by three factors: the largest contribution was from FXIII activity (partial R²=0.21), followed by platelet number (partial R²=0.14), and fibrinogen concentration (partial R²=0.095). During cardiopulmonary bypass, mean platelet count fell by a similar amount in the three groups (-36% to -41%; interaction P=0.98). Conversely, fibrinogen concentration increased in all three groups: 132% in the fibrinogen concentrate-supplemented group, 26% in the placebo group, and 51% in the low-risk group. A similar increase was observed for FXIII activity (61%, 23%, and 25%, respectively; interaction P<0.0001).

CONCLUSIONS

FXIII contribution to clot strength is considerable in infants undergoing cardiac surgery. Fibrinogen concentrate supplementation also increased FXIII activity, and hence clot strength.

CLINICAL TRIAL REGISTRATION

ISRCTN: 50553029.

Sustained Total All-Region Perfusion During the Norwood Operation and Postoperative Recovery

We developed a technique for the Norwood operation utilizing continuous perfusion of the head, heart, and lower body at mild hypothermia named Sustained Total All-Region (STAR) perfusion. We hypothesized that STAR perfusion would be associated with shorter operative times, decreased coagulopathy, and expedited post-operative recovery compared to standard perfusion techniques. Between 2012 and 2020, 80 infants underwent primary Norwood reconstruction at our institution. Outcomes for patients who received successful STAR perfusion (STAR, n = 37) were compared to those who received standard Norwood reconstruction utilizing regional cerebral perfusion only (SNR, n = 33), as well as to Norwood patients reported in the PC⁴ national database during the same timeframe (n = 1238). STAR perfusion was performed with cannulation of the innominate artery, descending aorta, and aortic root at 32-34°C. STAR patients had shorter median CPB time compared to SNR (171 vs 245 minutes, P < 0.0001), shorter operative time (331 vs 502 minutes, P < 0.0001), and decreased intraoperative pRBC transfusion (100 vs 270 mL, P < 0.0001). STAR patients had decreased vasoactive-inotropic score on ICU admission (6 vs 10.8, P = 0.0007) and decreased time to chest closure (2 vs 4.5 days, P = 0.0004). STAR patients had lower peak lactate (8.1 vs 9.9 mmol/L, P = 0.03) and more rapid lactate normalization (18.3 vs 27.0 hours, P = 0.003). In-hospital mortality in STAR patients was 2.7% vs 15.1% with SNR (P = 0.06) and 10.3% in the PC⁴ aggregate (P = 0.14). STAR perfusion is a novel approach to Norwood reconstruction associated with excellent survival, decreased transfusions, shorter operative time, and improved convalescence in the early post-operative period.

Prothrombin complex concentrate in cardiac surgery for the treatment of coagulopathic bleeding

BACKGROUND

Coagulopathy following cardiac surgery is associated with considerable blood product transfusion and high morbidity and mortality. The treatment of coagulopathy following cardiac surgery is challenging, with the replacement of clotting factors being based on transfusion of fresh frozen plasma (FFP). Prothrombin complex concentrate (PCCs) is an alternative method to replace clotting factors and warrants evaluation. PCCs are also an alternative method to treat refractory ongoing bleeding post-cardiac surgery compared to recombinant factor VIIa (rFVIIa) and also warrants evaluation.   OBJECTIVES: Assess the benefits and harms of PCCs in people undergoing cardiac surgery who have coagulopathic non-surgical bleeding.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE, Embase and Conference Proceedings Citation Index-Science (CPCI-S) on the Web of Science on 20 April 2021. We searched Clinicaltrials.gov (www.

CLINICALTRIALS

gov), and the World Health Organisation (WHO) International Clinical Trials Registry Platform (ICTRP; apps.who.int/trialsearch/), for ongoing or unpublished trials. We checked the reference lists for additional references. We did not limit the searches by language or publication status.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised trials (NRSs).  DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane.   MAIN RESULTS: Eighteen studies were included  (4993 participants). Two were RCTs (151 participants) and 16 were NRSs. Both RCTs had low risk of bias (RoB) in almost all domains. Of the 16 NRSs, 14 were retrospective cohort analyses with one prospective study and one case report. The nine studies used in quantitative analysis were judged to have critical RoB, three serious and three moderate.   1. PCC versus standard treatment Evidence from RCTs showed PCCs are likely to reduce the number of units transfused compared to standard care (MD -0.89, 95% CI -1.78 to 0.00; participants = 151; studies = 2; moderate-quality evidence). Evidence from NRSs agreed with this, showing that PCCs may reduce the mean number of units transfused compared to standard care but the evidence is uncertain (MD -1.87 units, 95% CI -2.53 to -1.20; participants = 551; studies = 2; very low-quality evidence). There was no evidence from RCTs showing a difference in the incidence of red blood cell (RBC) transfusion compared to standard care (OR 0.53, 95% CI 0.20 to 1.40; participants = 101; studies = 1; low-quality evidence). Evidence from NRSs disagreed with this, showing that PCCs may reduce the mean number of units transfused compared to standard care but the evidence is uncertain (OR 0.54, 95% CI 0.30 to 0.98; participants = 1046; studies = 4; low-quality evidence). There was no evidence from RCTs showing a difference in the number of thrombotic events with PCC compared to standard care (OR 0.68 95% CI 0.20 to 2.31; participants = 152; studies = 2; moderate-quality evidence). This is supported by NRSs, showing that PCCs may have no effect on the number of thrombotic events compared to standard care but the evidence is very uncertain (OR 1.32, 95% CI 0.87 to 1.99; participants = 1359; studies = 7; very low-quality evidence). There was no evidence from RCTs showing a difference in mortality with PCC compared to standard care  (OR 0.53, 95% CI 0.12 to 2.35; participants = 149; studies = 2; moderate-quality evidence). This is supported by evidence from NRSs, showing that PCCs may have little to no effect on mortality compared to standard care but the evidence is very uncertain (OR 1.02, 95% CI 0.69 to 1.51; participants = 1334; studies = 6; very low-quality evidence). Evidence from RCTs indicated that there was little to no difference in postoperative bleeding (MD -107.05 mLs, 95% CI -278.92 to 64.83; participants = 151, studies = 2; low-quality evidence).  PCCs may have little to no effect on intensive care length of stay (RCT evidence: MD -0.35 hours, 95% CI -19.26 to 18.57; participants = 151; studies = 2; moderate-quality evidence) (NRS evidence: MD -18.00, 95% CI -43.14 to 7.14; participants = 225; studies = 1; very low-quality evidence) or incidence of renal replacement therapy (RCT evidence: OR 0.72, 95% CI 0.14 to 3.59; participants = 50; studies = 1; low-quality evidence) (NRS evidence: OR 1.46, 95% CI 0.71 to 2.98; participants = 684; studies = 2; very low-quality evidence). No studies reported on additional adverse outcomes.   2. PCC versus rFVIIa For this comparison, all evidence was provided from NRSs.  PCC likely results in a large reduction of RBCs transfused intra-operatively in comparison to rFVIIa (MD-4.98 units, 95% CI -6.37 to -3.59; participants = 256; studies = 2; moderate-quality evidence).  PCC may have little to no effect on the incidence of RBC units transfused comparative to rFVIIa; evidence is very uncertain (OR 0.16, 95% CI 0.02 to 1.56; participants = 150; studies = 1; very low-quality evidence). PCC may have little to no effect on the number of thrombotic events comparative to rFVIIa; evidence is very uncertain (OR 0.51, 95% CI 0.23 to 1.16; participants = 407; studies = 4; very low-quality evidence). PCC may have little to no effect on the incidence of mortality (OR 1.07, 95% CI 0.38 to 3.03; participants = 278; studies = 3; very low-quality evidence) or intensive care length of stay comparative to rFVIIa (MD -40 hours, 95% CI -110.41 to 30.41; participants = 106; studies = 1; very low-quality evidence); evidence is very uncertain . PCC may reduce bleeding (MD -674.34 mLs, 95% CI -906.04 to -442.64; participants = 150; studies = 1; very low-quality evidence) and incidence of renal replacement therapy (OR 0.29, 95% CI 0.12 to 0.71; participants = 106; studies = 1; very low-quality evidence) comparative to rFVIIa; evidence is very uncertain. No studies reported on other adverse events.  AUTHORS' CONCLUSIONS: PCCs could potentially be used as an alternative to standard therapy for coagulopathic bleeding post-cardiac surgery compared to FFP as shown by moderate-quality evidence and it may be an alternative to rFVIIa in refractory non-surgical bleeding but this is based on moderate to very low quality of evidence.

A prospective, controlled study on the utility of rotational thromboelastometry in surgery for acute type A aortic dissection

To evaluate the hemostatic system with ROTEM in patients undergoing surgery for acute type aortic dissection (ATAAD) using elective aortic procedures as controls. This was a prospective, controlled, observational study. The study was performed at a tertiary referral center and university hospital. Twenty-three patients with ATAAD were compared to 20 control patients undergoing elective surgery of the ascending aorta or the aortic root. ROTEM (INTEM, EXTEM, HEPTEM and FIBTEM) was tested at 6 points in time before, during and after surgery for ATAAD or elective aortic surgery. The ATAAD group had an activated coagulation coming into the surgical theatre. The two groups showed activation of both major coagulation pathways during surgery, but the ATAAD group consistently had larger deficiencies. Reversal of the coagulopathy was successful, although none of the groups reached elective baseline until postoperative day 1. ROTEM did not detect low levels of clotting factors at heparin reversal nor low levels of platelets. This study demonstrated that ATAAD is associated with a coagulopathic state. Surgery causes additional damage to the hemostatic system in ATAAD patients as well as in patients undergoing elective surgery of the ascending aorta or the aortic root. ROTEM does not adequately catch the full coagulopathy in ATAAD. A transfusion protocol in ATAAD should be specifically created to target this complex coagulopathic state and ROTEM does not negate the need for routine laboratory tests.

Use of Fresh-frozen Plasma in Newborn Infants

Nearly 10% of premature and critically ill infants receive fresh-frozen plasma (FFP) transfusions to reduce their high risk of bleeding. The authors have only limited data to identify relevant clinical predictors of bleeding and to evaluate the efficacy of FFP administration. There is still no consensus on the optimal use of FFP in infants who have abnormal coagulation parameters but are not having active bleeding. The aims of this review are to present current evidence derived from clinical studies focused on the use of FFP in neonatology and then use these data to propose best practice recommendations for the safety of neonates receiving FFP.

Citrate does not change viscoelastic haemostatic assays after cardiopulmonary bypass

CONTEXT

Viscoelastic hemostatic assays (VHA) are commonly used to identify specific cellular and humoral causes for bleeding in cardiac surgery patients. Cardiopulmonary bypass (CPB) alterations to coagulation are observable on VHA. Citrated VHA can approximate fresh whole blood VHA when kaolin is used as the activator in healthy volunteers. Some have suggested that noncitrated blood is more optimal than citrated blood for point-of-care analysis in some populations.

AIMS

To determine if storage of blood samples in citrate after CPB alters kaolin activated VHA results.

SETTINGS AND DESIGN

This was a prospective observational cohort study at a single tertiary care teaching hospital.

METHODS AND MATERIAL

Blood samples were subjected to VHA immediately after collection and compared to samples drawn at the same time and stored in citrate for 30, 90, and 150 min prior to kaolin activated VHA both before and after CPB.

STATISTICAL ANALYSIS USED

VHA results were compared using paired T-tests and Bland-Altman analysis.

RESULTS

Maximum clot strength and time to clot initiation were not considerably different before or after CPB using paired T-tests or Bland-Altman Analysis.

CONCLUSIONS

Citrated samples appear to be a clinically reliable substitute for fresh samples for maximum clot strength and time to VHA clot initiation after CPB. Concerns about the role of citrate in altering the validity of the VHA samples in the cardiac surgery population seem unfounded.

Titrated versus conventional anticoagulation management for thrombin generation in cardiac surgery: a randomized controlled trial

PURPOSE

Optimal heparin titration during cardiopulmonary bypass (CPB) may reduce coagulation system activation and preserve hemostatic function post-CPB. Our objective was to assess if the Heparin Management System (HMS) Plus improves heparin titration, thereby leading to higher thrombin generation post-CPB compared with activated clotting time (ACT)-guided management.

METHODS

We conducted a randomized controlled trial of 100 patients undergoing cardiac surgery with CPB at a single center. A total of 50 patients were randomized to conventional ACT-guided management, and 50 to the HMS Plus system. The primary outcome was change in thrombin generation post-CPB compared with baseline, as assessed by calibrated automated thrombography. Secondary outcomes included intraoperative blood loss, chest drain output up to 72 hr, and transfusions. In an exploratory analysis, we compared the quintile of patients with the highest average heparin concentration on CPB (≥ 4.0 mg⋅kg-1) with the rest of the cohort.

RESULTS

A total of 100 patients were included in an intent-to-treat analysis. We observed no difference in post-CPB thrombin generation or secondary outcomes. However, patients in the HMS Plus group had higher average heparin concentrations while on CPB than patients in the conventional management group did (mean difference, -0.21; 95% confidence interval, -0.42 to -0.01). The quintile of patients with the highest average heparin concentration (4.0 mg⋅kg-1) had higher thrombin generation post-CPB than the rest of the cohort did.

CONCLUSIONS

The HMS Plus system did not show significant benefits in thrombin generation, bleeding outcomes, or transfusion in patients undergoing cardiac surgery with CPB. Higher average heparin concentrations on CPB were associated with higher post-CPB thrombin generation.

STUDY REGISTRATION

www.

CLINICALTRIALS

gov (NCT03347201); first submitted 12 October 2017.

Immediate Higher-Dose Prothrombin Complex Concentrate Without Fresh Frozen Plasma or Fibrinogen Concentrate for Significant Coagulopathic Cardiac Surgical Field Bleeding

BACKGROUND

Treatment of significant coagulopathic cardiac surgical field bleeding with immediate higher-dose prothrombin complex concentrate (PCC) without fresh frozen plasma (FFP) or fibrinogen concentrate is unexplored.

AIMS

To study characteristics, chest drainage, and clinical outcomes of patients with significant coagulopathic surgical field bleeding treated with immediate higher-dose (defined at >15 IU/kg based on factor IX) PCC without FFP or fibrinogen concentrate.

METHODS

We screened sequential cardiac surgery patients. We reviewed electronic blood bank data, Australian Society of Cardiothoracic Surgery database information and anaesthetic, intensive care unit (ICU), ward and radiological charts and electronic data. We identified patients deemed by the operating surgeon to require treatment for significant coagulopathic surgical field bleeding who underwent immediate higher-dose PCC without FFP or fibrinogen concentrate.

RESULTS

Among 168 patients, we identified 30 who underwent immediate higher-dose PCC without FFP or fibrinogen concentrate. Median age was 68 years, 23 were male, 17 underwent coronary artery bypass surgery and three underwent complex surgery (David procedure, redo mitral valve surgery, and redo thoraco-abdominal aneurysm repair). Median dose of PCC was 2,500 IU. In addition, 27% underwent platelets and one underwent cryoprecipitate. Chest drainage at 24 hours was 505 ml. Survival to hospital discharge was 100%. There were no cases of pulmonary embolism, stroke, or other thrombotic events. Stage 1 AKI occurred in one patient.

CONCLUSION

In a pilot cohort of patients with significant coagulopathic surgical field bleeding, immediate higher-dose PCC without FFP or fibrinogen concentrate was feasible and had an acceptable efficacy and safety profile, which justifies future controlled studies.

An Agreement Study Between Point-of-Care and Laboratory Activated Partial Thromboplastin Time for Anticoagulation Monitoring During Extracorporeal Membrane Oxygenation

Background

Laboratory activated partial thromboplastin time (LAB-aPTT) is a widely used laboratory assay for monitoring unfractionated heparin (UFH) therapy during extracorporeal membrane oxygenation (ECMO). But LAB-aPTT is confined to a central laboratory, and the procedure is time-consuming. In comparison, point-of-care aPTT (POC-aPTT) is a convenient and quick assay, which might be a promising method for anticoagulation monitoring in ECMO. This study was aimed to evaluate the agreement between POC-aPTT (hemochron Jr. Signature instruments) and LAB-aPTT for anticoagulation monitoring in adult ECMO patients.

Methods

Data of ECMO-supported adult patients anticoagulated with UFH in our institute from January 2017 to December 2020 was retrospectively reviewed. POC-aPTT and LAB-aPTT results measured simultaneously were paired and included in the analysis. The correlation between POC-aPTT and LAB-aPTT was assessed using Spearman’s correlation coefficient. Bias between POC-aPTT and LAB-aPTT were described with the Bland-Altman method. Influence factors for bias were identified using multinomial logistic regression analysis.

Results

A total 286 pairs of aPTT results from 63 patients were included in the analysis. POC-aPTT and LAB-aPTT correlated weakly (r = 0.385, P < 0.001). The overall bias between POC-aPTT and LAB-aPTT was 7.78 [95%CI (−32.49, 48.05)] s. The overall bias between POC-aPTT and LAB-aPTT ratio (to normal value) was 0.54 [95%CI (−0.68, 1.76)]. A higher plasma fibrinogen level [OR 1.353 (1.057, 1.733), P = 0.017] was associated with a higher chance of POC-aPTT underestimating LAB-aPTT. While a lower plasma fibrinogen level [OR 0.809 (0.679, 0.963), P = 0.017] and lower UFH rate [OR 0.928 (0.868, 0.992), P = 0.029] were associated with a higher chance of POC-aPTT overestimating LAB-aPTT.

Conclusion

The present study showed poor agreement between POC-aPTT and LAB-aPTT. POC-aPTT was not suitable for anticoagulation monitoring in adult ECMO patients.

A novel autotransfusion device saving erythrocytes and platelets used in a 72 h survival swine model of surgically induced controlled blood loss

Background

The purpose of this study was to develop a swine model of surgically induced blood loss to evaluate the performances of a new autotransfusion system allowing red blood cells and platelets preservation while collecting, washing and concentrating hemorrhagic blood intraoperatively.

Methods

Two types of surgically induced blood loss were used in 12 minipigs to assess system performance and potential animal complications following autotransfusion: a cardiac model (cardiopulmonary bypass) and a visceral model (induced splenic bleeding). Animal clinical and hematological parameters were evaluated at different time-points from before bleeding to the end of a 72-hour post-transfusion period and followed by a post-mortem examination. System performances were evaluated by qualitative and quantitative parameters.

Results

All animals that received the autotransfusion survived. Minimal variations were seen on the red blood cell count, hemoglobin, hematocrit at the different sampling times. Coagulation tests failed to show any hypo or hypercoagulable state. Gross and histologic examination didn’t reveal any thrombotic lesions. Performance parameters exceeded set objectives in both models: heparin clearance (≥ 90%), final heparin concentration (≤ 0.5 IU/mL), free hemoglobin washout (≥ 90%) and hematocrit (between 45% and 65%). The device treatment rate of diluted blood was over 80 mL/min.

Conclusions

In the present study, both animal models succeeded in reproducing clinical conditions of perioperative cardiac and non-cardiac blood loss. Sufficient blood was collected to allow evaluation of autotransfusion effects on animals and to demonstrate the system performance by evaluating its capacity to collect, wash and concentrate red blood cells and platelets. Reinfusion of the treated blood, containing not only concentrated red blood cells but also platelets, did not lead to any postoperative adverse nor thrombogenic events. Clinical and comparative studies need to be conducted to confirm the clinical benefit of platelet reinfusion.

Efficacy of prothrombin complex concentrate (PCC) versus fresh frozen plasma (FFP) in reducing perioperative blood loss in cardiac surgery: study protocol for a non-inferiority, randomised controlled trial

OBJECTIVE

To explore whether prothrombin complex concentrate (PCC) is not inferior to fresh frozen plasma (FFP) with regard to reducing perioperative blood loss in patients undergoing cardiac surgery under cardiopulmonary bypass (CPB).

SETTING

Fu Wai Hospital, and Peking Union Medical College Hospital in China.

PARTICIPANTS

Patients undergoing elective coronary artery bypass grafting, valve replacement or valvuloplasty under CPB, between 18 and 80 years old, will be included.

DESIGN

This study is a non-inferiority, randomised controlled clinical trial. A total of 594 subjects will be randomly assigned to two groups (group PCC and group FFP) and given corresponding interventions when at least one of the following criteria is met: (1) international normalised ratio >1.7 measured 20 min after CPB, (2) prolonged prothrombin time or activated partial thromboplastin time (>1.5 times baseline) measured 20 min after CPB and (3) excessive bleeding observed. 4-factor PCC (15 IU/kg) and FFP (10 mL/kg) will be given to group PCC and group FFP, respectively. Preoperative management, anaesthetic and surgical techniques will be standardised for both groups.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is the volume of blood loss during and within 24 hours after surgery. The secondary outcomes include (1) the total units of allogeneic red blood cells transfused during and within 7 days after surgery, (2) re-exploration due to postoperative bleeding within 7 days after surgery, (3) adverse events and serious adverse events within 30 days after surgery and (4) length of intensive care unit stay and hospital stay.

TRIAL REGISTRATION NUMBER

Registered under NCT04244981 at ClinicalTrials.gov on 28 January 2020, https://clinicaltrials.gov/ct2/show/NCT04244981?cond=NCT04244981&draw=2&rank=1.

ETHICS AND DISSEMINATION

This study has been approved by the Institutional Review Board of Peking Union Medical College Hospital (ZS-2242).

Anesthesia Considerations in Infective Endocarditis

The management of infective endocarditis is complex and inherently requires multidisciplinary cooperation. About half of all patients diagnosed with infective endocarditis will meet the criteria to undergo cardiac surgery, which regularly takes place in urgent or emergency settings. The pathophysiology and clinical presentation of infective endocarditis make it a unique disorder within cardiac surgery that warrants a thorough understanding of specific characteristics in the perioperative period. This includes, among others, echocardiography, coagulation, bleeding management, or treatment of organ dysfunction. In this narrative review article, the authors summarize the current knowledge on infective endocarditis relevant for the clinical anesthesiologist in perioperative management of respective patients. Furthermore, the authors advocate for the anesthesiologist to become a structural member of the endocarditis team.

The association of thrombin generation with bleeding outcomes in cardiac surgery: a prospective observational study

BACKGROUND

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with coagulopathic bleeding. Impaired thrombin generation may be an important cause of coagulopathic bleeding but is poorly measured by existing hemostatic assays. We examined thrombin generation during cardiac surgery, using calibrated automated thrombography, and its association with bleeding outcomes.

METHODS

We conducted a prospective observational study in 100 patients undergoing cardiac surgery with CPB. Calibrated automated thrombography parameters were expressed as a ratio of post-CPB values divided by pre-CPB values. The association of thrombin generation parameters for bleeding outcomes was compared with conventional tests of hemostasis, and the outcomes of patients with the most severe post-CPB impairment in thrombin generation (≥ 80% drop from baseline) were compared with the rest of the cohort.

RESULTS

All 100 patients were included in the final analysis, with a mean age of 63 (12) yr, 31 (31%) female, and 94 (94%) undergoing bypass and/or valve surgery. Post-CPB, peak thrombin decreased by a median of 73% (interquartile range [IQR], 49-91%) (P < 0.001) and total thrombin generation, expressed as the endogenous thrombin potential (ETP), decreased 56% [IQR, 30-83%] (P < 0.001). In patients with ≥ 80% decrease in ETP, 21% required re-exploration for bleeding compared with 7% in the rest of the cohort (P = 0.04), and 48% required medical or surgical treatment for hemostasis compared with 27% in the rest of the cohort (P = 0.04).

CONCLUSIONS

Thrombin generation is significantly impaired by CPB and associated with higher bleeding severity. Clinical studies aimed at the identification and treatment of patients with impaired thrombin generation are warranted.

Platelet function assessed by ROTEM® platelet in patients receiving antiplatelet therapy during cardiac and vascular surgery

Patients undergoing coronary artery bypass graft (CABG) surgery or carotid endarterectomy (CEA) continue antiplatelet therapy perioperatively, which may increase bleeding risk. We aimed to investigate whether Rotational thromboelastometry (ROTEM^®) platelet, a newly marketed platelet function analysis, would detect antiplatelet therapy in CABG and CEA patients; whether detection of reduced platelet function was associated with increased bleeding; and whether ex vivo desmopressin increased platelet function. We included 20 CABG patients continuing aspirin and 20 CEA patients continuing clopidogrel (n = 1) or clopidogrel and aspirin (n = 19). Platelet function was analyzed with ROTEM^® platelet and light transmission aggregometry (LTA). According to the lower reference limit, ROTEM^® platelet managed to detect aspirin, but clopidogrel detection was inadequate compared to LTA. Using a previously published cut-off for bleeding risk, 6 (30%) patients receiving aspirin and 4 (21%) patients receiving both clopidogrel and aspirin demonstrated platelet function below this cut-off. One of the four CEA patients below the cut-off died from intracerebral hemorrhage postoperatively. CABG patients below (n = 6) and above (n = 14) the cut-off did not differ in chest tube output (median [range]: 373 ml [250-900] vs. 368 ml [195-820]). Ex vivo addition of desmopressin did not increase platelet function. In conclusion, ROTEM^® platelet does reveal aspirin treatment whereas clopidogrel treatment is most often overlooked. Due to low bleeding in the study population, it was not possible to conclude on the association with bleeding risk.

Imaging the dynamics and microstructure of fibrin clot polymerization in cardiac surgical patients using spectrally encoded confocal microscopy

During cardiac surgery with cardiopulmonary bypass (CPB), altered hemostatic balance may disrupt fibrin assembly, predisposing patients to perioperative hemorrhage. We investigated the utility of a novel device termed spectrally-encoded confocal microscopy (SECM) for assessing fibrin clot polymerization following heparin and protamine administration in CPB patients. SECM is a novel, high-speed optical approach to visualize and quantify fibrin clot formation in three dimensions with high spatial resolution (1.0 μm) over a volumetric field-of-view (165 × 4000 × 36 μm). The measurement sensitivity of SECM was first determined using plasma samples from normal subjects spiked with heparin and protamine. Next, SECM was performed in plasma samples from patients on CPB to quantify the extent to which fibrin clot dynamics and microstructure were altered by CPB exposure. In spiked samples, prolonged fibrin time (4.4 ± 1.8 to 49.3 ± 16.8 min, p < 0.001) and diminished fibrin network density (0.079 ± 0.010 to 0.001 ± 0.002 A.U, p < 0.001) with increasing heparin concentration were reported by SECM. Furthermore, fibrin network density was not restored to baseline levels in protamine-treated samples. In CPB patients, SECM reported lower fibrin network density in protaminized samples (0.055 ± 0.01 A.U. [Arbitrary units]) vs baseline values (0.066 ± 0.009 A.U.) (p = 0.03) despite comparable fibrin time (baseline = 6.0 ± 1.3, protamine = 6.4 ± 1.6 min, p = 0.5). In these patients, additional metrics including fibrin heterogeneity, length and straightness were quantified. Note, SECM revealed that following protamine administration with CPB exposure, fibrin clots were more heterogeneous (baseline = 0.11 ± 0.02 A.U, protamine = 0.08 ± 0.01 A.U, p = 0.008) with straighter fibers (baseline = 0.918 ± 0.003A.U, protamine = 0.928 ± 0.0006A.U. p < 0.001). By providing the capability to rapidly visualize and quantify fibrin clot microstructure, SECM could furnish a new approach for assessing clot stability and hemostasis in cardiac surgical patients.

The Efficacy of Resin Hemoperfusion Cartridge on Inflammatory Responses during Adult Cardiopulmonary Bypass

AIM

This study aimed to evaluate the efficacy of the resin hemoperfusion device (HA380 hemoperfusion cartridge) on inflammatory responses during adult cardiopulmonary bypass (CPB).

METHODS

Sixty patients undergoing surgical valve replacement were randomized into the HP group (n = 30) with an HA380 hemoperfusion cartridge in the CPB circuit or the control group (n = 30) with the conventional CPB circuit. The results of routine blood tests, blood biochemical indexes, and inflammatory factors were analyzed at V0 (pre-CPB), V1 (CPB 30 min), V2 (ICU 0 h), V3 (ICU 6 h), and V4 (ICU 24 h).

RESULTS

The HP group had significantly lower levels of IL-6, IL-8, and IL-10. Significant estimation of group differences in the generalized estimating equation (GEE) models was also observed in IL-6 and IL-10. The HP group had significantly lower levels of creatinine (Cr), aminotransferase (AST), and total bilirubin (TBil) compared to the control group. The estimation of differences of Cr, AST, and TBil all reached statistical significance in GEE results. The HP group had significantly less vasopressor requirement and shorter mechanical ventilation time and ICU stay time as compared to the control group.

CONCLUSION

The HA380 hemoperfusion cartridge could effectively reduce the systemic inflammatory responses and improve postoperative recovery of patients during adult CPB.

Comparison of 4-Factor Prothrombin Complex Concentrate With Frozen Plasma for Management of Hemorrhage During and After Cardiac Surgery: A Randomized Pilot Trial

IMPORTANCE

Approximately 15% of patients undergoing cardiac surgery receive frozen plasma (FP) for bleeding. Four-factor prothrombin complex concentrates (PCCs) have logistical and safety advantages over FP and may be a suitable alternative.

OBJECTIVES

To determine the proportion of patients who received PCC and then required FP, explore hemostatic effects and safety, and assess the feasibility of study procedures.

DESIGN, SETTING, AND PARTICIPANTS

Parallel-group randomized pilot study conducted at 2 Canadian hospitals. Adult patients requiring coagulation factor replacement for bleeding during cardiac surgery (from September 23, 2019, to June 19, 2020; final 28-day follow-up visit, July 17, 2020). Data analysis was initiated on September 15, 2020.

INTERVENTIONS

Prothrombin complex concentrate (1500 IU for patients weighing ≤60 kg and 2000 IU for patients weighing >60 kg) or FP (3 U for patients weighing ≤60 kg and 4 U for patients weighing >60 kg), repeated once as needed within 24 hours (FP used for any subsequent doses in both groups). Patients and outcome assessors were blinded to treatment allocation.

MAIN OUTCOMES AND MEASURES

Hemostatic effectiveness (whether patients received any hemostatic therapies from 60 minutes to 4 and 24 hours after initiation of the intervention, amount of allogeneic blood components administered within 24 hours after start of surgery, and avoidance of red cell transfusions within 24 hours after start of surgery), protocol adherence, and adverse events. The analysis set comprised all randomized patients who had undergone cardiac surgery, received at least 1 dose of either treatment, and provided informed consent after surgery.

RESULTS

Of 169 screened patients, 131 were randomized, and 101 were treated (54 with PCC and 47 with FP), provided consent, and were included in the analysis (median age, 64 years; interquartile range [IQR], 54-73 years; 28 [28%] were female; 82 [81%] underwent complex operations). The PCC group received a median 24.9 IU/kg (IQR, 21.8-27.0 IU/kg) of PCC (2 patients [3.7%; 95% CI, 0.4%-12.7%] required FP). The FP group received a median 12.5 mL/kg (IQR, 10.0-15.0 mL/kg) of FP (4 patients [8.5%; 95% CI, 2.4%-20.4%] required >2 doses of FP). Hemostatic therapy was not required at the 4-hour time point for 43 patients (80%) in the PCC group and for 32 patients (68%) in the FP group (P = .25) nor at the 24-hour time point for 41 patients (76%) in the PCC group and for 31 patients (66%) patients in the FP group (P = .28). The median numbers of units for 24-hour cumulative allogeneic transfusions (red blood cells, platelets, and FP) were 6.0 U (IQR, 4.0-11.0 U) in the PCC group and 14.0 U (IQR, 8.0-20.0 U) in the FP group (ratio, 0.58; 95% CI, 0.45-0.77; P < .001). After exclusion of FP administered as part of the investigational medicinal product, the median numbers of units were 6.0 U (IQR, 4.0-11.0 U) in the PCC group and 10.0 U (IQR, 6.0-16.0 U) in the FP group (ratio, 0.80; 95% CI, 0.59-1.08; P = .15). For red blood cells alone, the median numbers were 1.5 U (IQR, 0.0-4.0 U) in the PCC group and 3.0 U (IQR, 1.0-5.0 U) in the FP group (ratio, 0.69; 95% CI, 0.47-0.99; P = .05). During the first 24 hours after start of surgery, 15 patients in the PCC group (28%) and 8 patients in the FP group (17%) received no red blood cells (P = .24). Adverse event profiles were similar.

CONCLUSIONS AND RELEVANCE

This randomized clinical trial found that the study protocols were feasible. Adequately powered randomized clinical trials are warranted to determine whether PCC is a suitable substitute for FP for mitigation of bleeding in cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04114643.

Managing the coagulopathy associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has allowed for significant surgical advancements, but accompanying risks can be significant and must be expertly managed. One of the foremost risks is coagulopathic bleeding. Increasing levels of bleeding in cardiac surgical patients at the time of separation from CPB are associated with poor outcomes and mortality. CPB-associated coagulopathy is typically multifactorial and rarely due to inadequate reversal of systemic heparin alone. The components of the bypass circuit induce systemic inflammation and multiple disturbances of the coagulation and fibrinolytic systems. Anticipating coagulopathy is the first step in managing it, and specific patient and procedural risk factors have been identified as predictors of excessive bleeding. Medication management pre-procedure is critical, as patients undergoing cardiac surgery are commonly on anticoagulants or antiplatelet agents. Important adjuncts to avoid transfusion include antifibrinolytics, and perfusion practices such as red cell salvage, sequestration, and retrograde autologous priming of the bypass circuit have varying degrees of evidence supporting their use. Understanding the patient's coagulation status helps target product replacement and avoid larger volume transfusion. There is increasing recognition of the role of point-of-care viscoelastic and functional platelet testing. Common pitfalls in the management of post-CPB coagulopathy include overdosing protamine for heparin reversal, imperfect laboratory measures of thrombin generation that result in normal or near-normal laboratory results in the presence of continued bleeding, and delayed recognition of surgical bleeding. While challenging, the effective management of CPB-associated coagulopathy can significantly improve patient outcomes.

Fibrin clot susceptibility to lysis is impaired after on-pump coronary artery by-pass grafting with tranexamic acid: clinical implications

Coronary artery bypass grafting (CABG) done on-pump may cause a significant blood loss. Low fibrinogen is associated with perioperative bleeding. The influence of cardiopulmonary bypass on fibrin clot properties is poorly investigated. We studied 55 patients with isolated coronary artery disease on aspirin undergoing on-pump CABG with tranexamic acid. Fibrinogen levels, fibrinolytic capacity expressed as clot lysis time (CLT), thrombin generation potential and platelet count were assessed before and after the surgery (prior to admission to the intensive care unit). A postoperative drop in haemoglobin (-30% from baseline), haematocrit (-31% from baseline) and platelet count (-42% from baseline) was observed (all, P < 0.0001). Postoperative fibrinogen level was lower by 57%, compared with preoperative value (1.5 [1.3-1.8] vs. 3.5 [2.8-3.9] g/l, P < 0.0001). Postoperative CLT was longer by 48 min, compared with preoperative (182 [170-218] vs. 134 [122-165] min, P < 0.0001). Thrombin generation was impaired postoperatively: both lag time and time to peak thrombin were prolonged by 44 and 45%, respectively, whereas endogenous thrombin potential and peak thrombin generation decreased by 45 and 78%, respectively (all P < 0.0001). Median postoperative drainage at 12 h was 400 [290-570] ml. Predictors of blood loss at 12 h identified in multivariable linear regression model adjusted for sex and preoperative fibrinogen level were: BMI (b = -23.4, P = 0.048) and postoperative CLT (b = -2.4, P = 0.042). Despite decreased fibrinogen levels after on-pump CABG with tranexamic acid, fibrin clot susceptibility to lysis is impaired, as reflected by prolonged CLT. Postoperative CLT is associated with mediastinal drainage at 12 h.

Role of Using a Thromboelastometry-Based Protocol for Transfusion Management in Combined Coronary Artery Bypass Grafting and Valve Surgery: A Randomized Clinical Trail

The aim of this study was to evaluate the impact of using a thromboelastometry-based protocol on transfusion requirements in patients undergoing combined coronary artery bypass grafting (CABG) and valve surgery. 80 adult patients scheduled for elective combined CABG and valve surgery were included in this clinical trial study. Patients were randomly allocated to the thromboelastometry (ROTEM) (n = 40) or control groups (n = 40). In the ROTEM group, transfusion was directed according to a thromboelastometry-based protocol. In the control group, transfusion was conducted according to the routine practices including conventional coagulation testing and clinical judgments. Finally, transfusion requirements were compared between groups. Use of thromboelastometry- based protocol resulted in 67% reduction in blood products units' consumption as well as 23% in the percentage of patients transfused. This reduction was especially evident in relation to fresh frozen plasma (FFP) and platelet consumption. No significant differences were found both in the percentage of patients receiving RBC and number of transfused RBC units. Using thromboelastometry tests incorporated a protocol results in reduction of transfusion requirements in patients undergoing elective combined CABG and valve surgery.

Acute Kidney Injury in Patients Undergoing Cardiopulmonary Bypass for Lung Transplantation

BACKGROUND

Cardiopulmonary bypass (CPB) is often used to support patients undergoing lung transplantation who are intolerant of anatomic manipulation or single lung ventilation during the procedure. However, CPB may be associated with adverse outcomes. We evaluated the hypothesis that CPB is associated with increased acute kidney injury (AKI) and postoperative mortality after lung transplantation.

MATERIALS AND METHODS

This was a retrospective review of our institutional lung transplant database at the University of Texas Southwestern Medical Center from 2012 to 2018. Patients were grouped based on their need for CPB. The primary outcome was AKI within 48 h of transplantation, which was defined as Kidney Disease Improving Global Outcomes stage 1 or greater. Secondary outcomes included all-cause mortality.

RESULTS

A total of 426 patients underwent lung transplantation with 39.0% (n = 166) requiring CPB. There were no differences in demographics and comorbidities, including baseline renal function, between CPB and no CPB. CPB use was higher in recipients with interstitial lung diseases and primary pulmonary hypertension. Median lung allocation score was higher in those needing CPB (47 [interquartile range, 40-59] versus 39 [interquartile range, 35-47]). Patients requiring CPB were significantly more likely to experience AKI (61.44% versus 36.5.3%, P < 0.01) and postoperative hemodialysis (6.6% versus 0.4%, P < 0.01). On multivariable analysis, CPB was significantly associated with postoperative AKI (odds ratio, 1.66; 95% CI, 1.01-2.75; P = 0.04). Thirty-day mortality was higher in patients undergoing CPB (4.2% versus 0.8%, P = 0.03).

CONCLUSIONS

CPB for lung transplantation is associated with a higher incidence of AKI, renal failure requiring hemodialysis, and 30-d mortality. CPB should be used selectively for lung transplantation.

Thrombin generation and bleeding in cardiac surgery: a clinical narrative review

This narrative review discusses the role of thrombin generation in coagulation and bleeding in cardiac surgery, the laboratory methods for clinical detection of impaired thrombin generation, and the available hemostatic interventions that can be used to improve thrombin generation. Coagulopathy after cardiopulmonary bypass (CPB) is associated with excessive blood loss and adverse patient outcomes. Thrombin plays a crucial role in primary hemostasis, and impaired thrombin generation can be an important cause of post-CPB coagulopathy. Existing coagulation assays have significant limitations in assessing thrombin generation, but whole-blood assays designed to measure thrombin generation at the bed-side are under development. Until then, clinicians may need to institute therapy empirically for non-surgical bleeding in the setting of normal coagulation measures. Available therapies for impaired thrombin generation include administration of plasma, prothrombin complex concentrate, and bypassing agents (recombinant activated factor VII and factor eight inhibitor bypassing activity). In vitro experiments have explored the relative potency of these therapies, but clinical studies are lacking. The potential incorporation of thrombin generation assays into clinical practice and treatment algorithms for impaired thrombin generation must await further clinical development.

Comparison of standard coagulation testing with thromboelastometry tests in cardiac surgery

Introduction: According to the several evidences, using thromboelastometry as a point of care test can be effective in reduction in blood loss and transfusion requirements in cardiac surgeries. However, there are limited data regarding to the comparison of thromboelastometry and the standard coagulation tests. In this study, we compared thromboelastometry and standard coagulation tests (PT, PTT and fibrinogen level) in patients under combined coronary-valve surgery. Methods: Forty adult patients who were under on-pump combined coronary-valve surgery were included in this study. Thromboelastometry tests Fibtem, Intem, Extem and Heptem), along with standard coagulation tests (PT, PTT and fibrinogen assay) were simultaneously performed in two time points, before and after the pump (pre-CPB and post-CPB, respectively). Results: A total of 80 blood samples were analyzed. There were no significant correlation between PT test and the CT-Extem parameter as well as PTT and CT-Intem parameter either in pre-CPB and post-CPB (P >0.05). On the contrary, fibrinogen level had high correlation with A10-Fibtem and A10-Extem in pre-PCB (P <0.05). 82% of PT and 84% of PTT measurements were outside the reference range, while abnormal CT in Extem and Intem was observed in 17.9%. Conclusion: For management of bleeding, adequate perioperative haemostatic monitoring is indispensable during cardiac surgery. Standard coagulation tests are time consuming and cannot be interchangeably used with thromboelastomety and relying on their results to decide whether blood transfusion is necessary, leads to the inappropriate transfusion.

Effects of Autologous Platelet Rich Plasma on Intraoperative Transfusion and Short-Term Outcomes in Total Arch Replacement (Sun's Procedure): A Prospective, Randomized Trial

OBJECTIVE

To observe the effect of collecting and retransfusing autologous platelet rich plasma (aPRP) on the amount of allogeneic blood usage in total arch replacement (Sun's surgery) and the outcomes 30 days after surgery.

DESIGN

A prospective, randomized trial.

SETTING

A tertiary university hospital specialized in cardiovascular diseases.

PARTICIPANTS

The study comprised 120 patients undergoing Sun's surgery for Stanford type A acute aortic dissection.

INTERVENTIONS

aPRP was harvested before incision and was re-transfused after heparin neutralization for patients in the treatment group.

MEASUREMENTS AND MAIN RESULTS

There was no significant difference in preoperative demographic data between the 2 study groups. Intraoperative transfusions of erythrocyte (p = 0.009), plasma (p = 0.017), cryoprecipitate (p = 0.002), and platelets (p < 0.001) in the treatment group were reduced significantly. In addition, less blood loss was observed in the treatment group (p = 0.002). The durations of postoperative mechanical ventilation (p = 0.029) and hospitalization (p = 0.002) of the treatment group were significantly shorter. There were no statistically significant differences in the length of intensive care unit stay, the incidence of complications, and mortality 30 days after surgery.

CONCLUSION

In total arch replacement (Sun's surgery), collecting and retransfusing aPRP reduced intraoperative transfusions of erythrocyte, plasma, and cryoprecipitate and decreased the duration of postoperative mechanical ventilation and hospitalization. This technique had no significant effect on the incidence of complications and mortality 30 days postoperatively.

Comparative Analysis of Prothrombin Complex Concentrate and Fresh Frozen Plasma in Coronary Surgery

BACKGROUND

Recent studies suggested that prothrombin complex concentrate (PCC) might be more effective than fresh frozen plasma (FFP) to reduce red blood cell (RBC) transfusion requirement after cardiac surgery.

METHODS

This is a comparative analysis of 416 patients who received FFP postoperatively and 119 patients who received PCC with or without FFP after isolated coronary artery bypass grafting (CABG).

RESULTS

Mixed-effects regression analyses adjusted for multiple covariates and participating centres showed that PCC significantly decreased RBC transfusion (67.2% vs. 87.5%, adjusted OR 0.319, 95%CI 0.136-0.752) and platelet transfusion requirements (11.8% vs. 45.2%, adjusted OR 0.238, 95%CI 0.097-0.566) compared with FFP. The PCC cohort received a mean of 2.7±3.7 (median, 2.0, IQR 4) units of RBC and the FFP cohort received a mean of 4.9±6.3 (median, 3.0, IQR 4) units of RBC (adjusted coefficient, -1.926, 95%CI -3.357-0.494). The use of PCC increased the risk of KDIGO (Kidney Disease: Improving Global Outcomes) acute kidney injury (41.4% vs. 28.2%, adjusted OR 2.300, 1.203-4.400), but not of KDIGO acute kidney injury stage 3 (6.0% vs. 8.0%, OR 0.850, 95%CI 0.258-2.796) when compared with the FFP cohort.

CONCLUSIONS

These results suggest that the use of PCC compared with FFP may reduce the need of blood transfusion after CABG.

Use of a flowable haemostat versus an oxidised regenerated cellulose agent in primary elective cardiac surgery: economic impact from a UK healthcare perspective

Background

Flowable haemostatic agents have been shown to be superior to non-flowable agents in terms of haemostatic control and need for transfusion products in patients undergoing cardiac surgery. We investigated the economic impact of the use of a flowable haemostatic agent (Floseal) compared with non-flowable oxidised regenerated cellulose (ORC) agent in primary elective cardiac surgery from the perspective of the UK National Health Service (NHS).

Methods

A cost-consequence framework based upon clinical data from a prospective trial and an observational trial and NHS-specific actual reference costs (2016) was developed to compare the economic impact of Floseal with that of ORC. The individual domains of care investigated comprised complications (major and minor) avoided, operating room time savings, surgical revisions for bleeding avoided and transfusions avoided. The cost impact of Floseal versus ORC on ICU days and extended bed days avoided was modelled separately.

Results

Compared with ORC, the use of Floseal would be associated with overall net savings to the NHS of £178,283 per 100 cardiac surgery patients who experience intraoperative bleeding requiring haemostatic therapy. Cost savings were apparent in all individual domains of care (complications avoided: £83,536; operating room time saved: £63,969; surgical revisions avoided: £34,038; and blood transfusions avoided: £22,317). Cost savings per 100 patients with Floseal over ORC in terms of ICU days avoided (n = 30) and extended bed days avoided (n = 51.7) were £57,960 and £21,965, respectively. A sensitivity analysis indicated that these findings remained robust when the model parameters representing the clinical benefit of Floseal over ORC were reduced by up to 20%.

Conclusions

Despite higher initial acquisition costs, the use of flowable haemostatic agents achieves substantial cost savings over non-flowable agents in cardiac surgery. These cost savings commence during the operating theatre and appear to continue to be realised throughout the postoperative period.

Electronic supplementary material

The online version of this article (10.1186/s13019-017-0660-y) contains supplementary material, which is available to authorized users.

Viscoelastic Monitoring to Guide Hemostatic Resuscitation in Liver Transplantation Surgery

Coagulopathic bleeding must be anticipated during liver transplantation (LT) surgery. Patients with end-stage liver disease (ESLD) often present with disease-related hematologic disturbances, including the loss of hepatic procoagulant and anticoagulant clotting factors and thrombocytopenia. Transplantation surgery itself presents additional hemostatic changes, including hyperfibrinolysis. Viscoelastic monitoring (VEM) is often used to provide targeted, personalized hemostatic therapies for complex bleeding states including cardiac surgery and major trauma. The use in these coagulopathic conditions led to its application to LT, although the mechanisms of coagulopathy in these patients are quite different. While VEM is often used during transplant surgeries in Europe and North America, evidence supporting its use is limited to a few small clinical studies. The theoretical and clinical applications of the standard and specialized VEM assays are discussed in the setting of LT and ESLD.