Cardiopulmonary bypass and the coagulation system

Dosing, Monitoring, Blood Product Utilization, and Thromboembolic Complications of Four-Factor Prothrombin Complex Concentrate as Part of an Institutional Protocol in Pediatric Cardiac Surgery: A Retrospective Cohort Study

Pediatric cardiac surgery patients are predisposed to blood loss. Blood product administration can lead to complications. Prothrombin complex concentrates (PCCs) offer potential advantages of factor composition, small volume, decreased immunogenicity/infectious risks, and accessibility. The objective of this study was to describe dosing, monitoring, blood product utilization, and thromboembolic complications of administering four-factor PCC (4F-PCC) in pediatric cardiac surgery. We performed a retrospective review of patients aged <18 years undergoing cardiac surgery from June 2020 to May 2022 (inclusive) who received 4F-PCC. Outcomes of interest included 4F-PCC dosing (units/kg) and number of doses administered, chest tube output, blood product administration, donor exposure, length of stay, and thromboembolic events. Eighty-six patients met eligibility criteria. The median (range) age and weight were 0.37 (0.01-16.3) years and 5.3 (1.6-98) kg, respectively. Median (range) total 4F-PCC dose per patient was 25 (9.2-50) units/kg, with 6 patients (7%) receiving a total of two doses. Median (range) 24-hour postoperative packed red blood cells, platelet, plasma, and cryoprecipitate administration volumes were 0 (0-2.57) mL/kg/24 h, 0 (0-1.09), 0 (0-2.64), and 0 (0-0.28 mL/kg/24 h), respectively. Median (range) length of stay and 24-hour postoperative chest tube output were 10 (6-26) days and 1.1 (0.1-4.2) mL/kg/h, respectively. Two (2%) patients experienced a thromboembolic event within 30 days of 4F-PCC administration. These retrospective findings suggest no worsening of hemostatic parameters, a mild median improvement in fibrinogen, low blood product utilization, and low thromboembolism rates following 4F-PCC use in pediatric cardiac surgery.

Efficacy and safety of aprotinin in paediatric cardiac surgery: A systematic review and meta-analysis

BACKGROUND

The relicensing of aprotinin in Europe and Canada has stimulated discussions on its usefulness in paediatric cardiac surgery.

OBJECTIVE

To systematically evaluate the available evidence on the efficacy and safety of aprotinin in paediatric cardiac surgery.

DESIGN

Systematic review of all randomised and observational studies comparing aprotinin with tranexamic acid, epsilon aminocaproic acid, placebo or no drug in paediatric cardiac surgery. Meta-analyses were performed on efficacy and safety outcomes.

DATA SOURCES

PubMed, Cochrane Central Register of Controlled Trials, Web of Science and Embase were searched from January 2000 to March 2021.

ELIGIBILITY CRITERIA

Studies that enrolled children under 18 years undergoing cardiac surgery with cardiopulmonary bypass.

RESULTS

Thirty-two studies enrolling a total of 63 894 paediatric cardiac procedures were included. Aprotinin significantly reduced total blood loss [mean difference -4.70 ml kg-1, 95% confidence interval (CI), -7.88 to -1.53; P = 0.004], postoperative transfusion requirements and the incidence of surgical re-exploration for bleeding [odds ratio (OR) 0.74, 95% CI, 0.56 to 0.97; P = 0.03]. Aprotinin had no effects on 30-day mortality (OR 1.02, 95% CI, 0.93 to 1.11; P = 0.73) and on other safety outcomes, except for the incidence of renal replacement therapy (RRT), which was significantly increased in patients given aprotinin (OR 1.29, 95% CI, 1.08 to 1.54; P = 0.006). Findings from observational and randomised controlled trials did not largely differ. A sub-group analysis in neonates showed that aprotinin significantly reduced packed red blood cell transfusions and the incidence of postoperative surgical re-exploration for bleeding and/or tamponade. When compared with lysine analogues, aprotinin was more effective at reducing bleeding and transfusion without increasing the risk of side effects.

CONCLUSION

This meta-analysis suggests that aprotinin is effective and well tolerated in paediatric cardiac surgery. Given the large heterogeneity of the results and the risk of selection bias in observational studies, large randomised controlled trials are warranted.

Application of a Modified Extracorporeal Circulation Perfusion Method During Surgery for Acute Stanford Type A Aortic Dissection

AIM

The aim of this study was to investigate the effect of the modified extracorporeal circulation perfusion method during surgery for acute Stanford type A aortic dissection in patients who underwent stented elephant trunk implantation and arch replacement.

METHOD

A total of 69 patients with acute Stanford type A aortic dissection who underwent stented elephant trunk implantation and arch replacement were retrospectively analysed from 2017 to 2018. According to the perfusion method of extracorporeal circulation, patients were divided into a routine perfusion (RP) group and a modified perfusion (MP) group. Clinical data were collected, including the time of extracorporeal circulation and deep hypothermic circulatory arrest, incidence of acute kidney injury and neurological complications, and comparisons between the two groups were conducted by using independent sample t-tests for normally distributed qualitative data, the Mann-Whitney U-test for skewed qualitative data, and the chi square test or Fisher's exact test for categorical data.

RESULTS

There were 55 (80%) males and 14 (20%) females in the entire cohort, and the mean ± standard deviation age was 50.4±9.0 years. A total of 53 (77%) patients were included in the RP group, and 16 (23%) were included in the MP group. Patients in the MP group were older (55.5±7.8 vs 48.8±8.9 years), and the difference was significant (p=0.008). Compared with the RP group, the time of extracorporeal circulation (218.0 [44.7] vs 246.0 [58.0] min; p=0.005) and deep hypothermic circulatory arrest (4.0 [2.0] vs 25.0 [10.0] min; p<0.001) was shorter, and the incidence of postoperative acute kidney injury (n=6 [37.5%] vs n=36 [67.9%]; p=0.029) was lower in the MP group; the differences were significant. Six (6) patients died in the RP group; no patients died in the MP group. The total in-hospital mortality rate was 8.7%.

CONCLUSIONS

The modified extracorporeal circulation perfusion method is feasible, with satisfactory results.

Prothrombin Complex Concentrates in Pediatric Cardiac Surgery: The Current State and the Future

BACKGROUND

After decades of practice of pediatric cardiac surgery, postoperative bleeding due to the immaturity of hemostasis, hemodilution, and hypothermia remains a concern. Recently, a new approach for adult coagulopathy after bypass has emerged. Prothrombin complex concentrates (PCCs), designed to treat bleeding in hemophilia patients, are safely and efficiently used off label for hemorrhage after bypass. However, optimal dosing, indications and contraindications, and laboratory tests to assess the efficacy of PCC use in children have not yet been established. This literature review outlines the challenges of bypass-related coagulopathy, the pharmacology, and the experience in use of PCCs, with a focus on their potential in pediatric cardiac surgery.

METHODS

After a thorough literature search of MEDLINE, Scopus, and Ovid databases using the term "prothrombin complex concentrate AND pediatric," 23 relevant articles were selected.

RESULTS

The data supporting successful use of PCCs in acquired coagulopathy after cardiac surgery in adults have been increasing. Although small volume, low immunogenicity, efficiency, and speed in correcting coagulopathy are attractive qualities of PCCs for pediatric practice, current evidence is only anecdotal. The main concerns are unknown dosing regimens, the inability to closely monitor the effects of PCCs in real time, and a possibility of thrombotic complications, which can be particularly devastating in young congenital cardiac patients whose lives frequently depend upon the patency of artificial shunts.

CONCLUSIONS

Extensive, high-quality research is warranted to fill in the gaps of knowledge regarding using PCCs in pediatric cardiac practice.

Reference values for kaolin-activated thromboelastography in volunteers of Anhui Province in China

BACKGROUND

The assessment of the coagulation status using thromboelastography (TEG) in Chinese population has less been reported. This study aimed to establish reliable reference values for kaolin-activated TEG in Chinese volunteers.

METHODS

A total of 1681 Chinese adult individuals were recruited for this study. The reference individuals were stratified by gender and age, and the TEG values were measured on the basis of strict quality control. The 95% reference values were determined using nonparametric statistical methods.

RESULTS

The sex-related 95% reference values were reaction time (R):4.2-8.7 minutes; clotting time (K): 1.2-3.2 minutes; alpha angle (α): 47.0-72.3 degree; maximum amplitude (MA): 49.1-70.5 mm for males, and R: 3.7-9.0 minutes; K: 1.0-3.2 minutes; α: 48.4-74.4 degree; MA: 46.8-72.4 mm for females. Also, the TEG parameters indicated a relatively more hypercoagulable profile in both female and elder groups.

CONCLUSIONS

This study established the reference values for kaolin-activated TEG in the target Chinese population, which might provide a reference for both clinical and laboratory studies.

Use of Confidex to control perioperative bleeding in pediatric heart surgery: prospective cohort study

Bleeding during and after cardiac surgery is a major issue in pediatric patients. A prospective cohort study was conducted to evaluate the effect of a commercially available prothrombin complex (Confidex) administered in cardiac surgery after weaning from cardiopulmonary bypass of infants with nonsurgical bleeding. In this study, 14 patients younger than 1 year received a Confidex bolus and were matched with 11 patients of a similar age who did not receive the drug. The preoperative coagulation profile was similar in the two groups. No side effects, including anaphylaxis or thrombotic events, were observed. The numbers of units of packed red blood cells and fresh frozen plasma administered both intra- and postoperatively were similar. The postoperative coagulation examination results and thromboelastographic parameters did not differ significantly between the two groups. However, the Confidex patients bled significantly less than the control subjects during the first 24 postoperative hours. The median volume of drained blood was 0.0 ml/kg h (range 0-1.9 ml/kg h) compared with 1.9 ml/kg h (range 1-3 ml/kg h) (p = 0.009). At least one unit of packed red blood cells in the postoperative phase was required by 2 patients (14 %) in the Confidex group and six patients (54 %) in the control group (odds ratio [OR], 0.13; 95 % confidence interval [CI], 0.02-0.9; p = 0.03). The median duration of mechanical ventilation was 3 days (range 2-4 days) in the Confidex group and 4 days (range 0-8 days) in the control group (p = 0.66). The median stay in the intensive care unit was 6 days (range 5-9 days) in the Confidex group and 7 days (range 4-12 days) in the control group (p = 0.88). The use of Confidex for infants undergoing cardiac surgery was safe and effective. It reduced postoperative bleeding and allowed fewer units of packed red blood cells to be infused in the postoperative phase without major side effects.

Anticoagulation for pediatric mechanical circulatory support

Extracorporeal life support applications have evolved considerably in recent years. However, the blood-biomaterial interface remains incompletely understood, and management of the acute inflammatory response and coagulation pathways continues to be challenging. At present, the gold standard for anticoagulation is unfractionated heparin. Since the inception of extracorporeal life support, the mainstay for anticoagulation monitoring has been activated clotting time. However, alongside the technological evolution in extracorporeal life support, the methods for monitoring heparin have also become more sophisticated, adding additional layers of complexity to creating an ideal safe protocol for anticoagulation during extracorporeal life support. To address this, the Extracorporeal Life Support Organization has formed an Anticoagulation Task Force to help direct both a consensus statement and potential guidelines within which the multiple monitoring methods can be customized for extracorporeal life support. One key question that remains in the use of these monitoring methods is whether the objective during extracorporeal life support is to anticoagulate the circuit to prevent thrombus formation within the extracorporeal device or whether it is to systemically anticoagulate the patient. This review details all current monitoring methods and highlights how they can be used during pediatric mechanical circulatory support.

Perioperative blood conservation strategies in pediatric patients undergoing open-heart surgery: impact of non-autologous blood transfusion and surface-coated extracorporeal circuits

BACKGROUND

The aim of this study was to explore the relative clinical and biomaterial effects of blood transfusions (Tx) and novel low-prime, surface-coated circuitry on perioperative outcome in a pediatric population undergoing cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

Over a 12-month period, 80 patients weighing >10 kg undergoing ventricular septal defect (VSD) repair with CPB were prospectively randomized into two groups according to the type of CBP circuit used, then each randomized group was enrolled into two groups again, according to the need for transfusion (N=20): Group 1- Tx-free procedures on low-prime, surface-coated extracorporeal circuitry (FX05, Terumo); Group 2- procedures requiring Tx on coated circuitry; Group 3- Tx-free procedures with standard uncoated circuitry (D902, Sorin); Group 4 (Control)- procedures requiring Tx on uncoated circuitry. Blood samples were collected at baseline (T1), at the end of the CPB (T2) and 24 h (T3) postoperatively. rSO(2) desaturation risk score >6000 (Invos, Somanetics) was calculated by multiplying rSO(2) <50% by time.

RESULTS

IL-6 levels (pg/ml) were significantly lower in Groups 1 and 3 versus control at T2 (13±4; 17±5 versus 33±8; p<0.05). CD11b/CD18 levels (%) were significantly lower in Group 1 (12±4) versus control (25±8) at T2 (p<0.05). Respiratory support time (h) was significantly less in Group 1 (11.4±6) versus control (19.8±7) (p<0.05). rSO(2) desaturation risk >6000 (%) was 15.7±9 in Group 1 and 26.8±11 in control (p<0.05).

CONCLUSION

Allogenic Tx amplifies the CPB-related inflammatory response. It is feasible to do congenital procedures safely without Tx for patients weighing >10 kg by using combined blood management strategies.