Hypothermic circulatory arrest induced coagulopathy: rotational thromboelastometry analysis

Hypothermic circulatory arrest at 20 ℃ does not deteriorate coagulopathy compared to 28 ℃ in a pig model

It is believed that a lower temperature setting of hypothermic circulatory arrest (HCA) in thoracic aortic surgery causes coagulopathy, resulting in excessive bleeding. However, experimental studies that eliminate clinical factors are lacking. The objective of this study is to investigate the influence of the temperature setting of HCA on coagulation in a pig model. Ten pigs were divided into the following two groups: moderate temperature at 28 °C (group M, n = 5) or lower temperature at 20 °C (group L, n = 5). Two hours of HCA during a total of 4 h of cardiopulmonary bypass (CPB) were performed. Blood samples were obtained at the beginning (T1) and the end (T2) of the surgery, and coagulation capability was analyzed through standard laboratory tests (SLTs) and rotational thromboelastometry (ROTEM). In SLTs, hemoglobin, fibrinogen, platelet count, prothrombin time, and activated partial thromboplastin time were analyzed. In ROTEM analyses, clotting time and clot formation time of EXTEM, maximum clot firmness (MCF), and maximum clot elasticity (MCE) of EXTEM and FIBTEM were analyzed. Fibrinogen decreased significantly in both groups (group M, p = 0.008; group L, p = 0.0175) at T2, and FIBTEM MCF and MCE also decreased at T2. There were no differences regarding changes in parameters of SLTs and ROTEM between groups. CPB decreases coagulation capacity, contributed by fibrinogen. However, a lower temperature setting of HCA at 20 °C for 2 h did not significantly affect coagulopathy compared to that of HCA at 28 °C after re-warming to 37 °C.

Open aortic arch repair without circulatory arrest by frozen elephant trunk in Ishimaru zone 0

BACKGROUND

Open arch surgery is technically demanding for the surgeon and surgically and biologically invasive for the patient, requiring a variably long period of hypothermic circulatory arrest.

CASE PRESENTATION

Here we present a case of an elderly patient with chronic renal failure and multiple splanchnic artery disease successfully treated for a rupturing pseudoaneurysm of the aortic arch with a technique that we developed for particularly frail patients. The procedure includes: triple supra-aortic vessel perfusion; distal thoracic aorta antegrade perfusion; balloon endo-clamping of the descending aorta; and anastomosis of an off-the-shelf hybrid arch prosthesis in Ishimaru zone 0. These maneuvers allowed to maintain an extracorporeal circulation in the phase of distal anastomosis, instead of a period of circulatory arrest, employing just mild hypothermia: technical details are depicted and discussed also in comparison with other methods proposed in the literature.

CONCLUSIONS

Being able to take advantage of both open surgery advancements and endovascular methods is the key to cardiovascular surgery success today in front of complex pathologies of the aorta: increasing safety and reducing invasiveness of therapeutic options may progressively extend surgical candidacy to the frailest patients.

Hypothermic Circulatory Arrest in Adult Aortic Arch Surgery: A Review of Hypothermic Circulatory Arrest and its Anesthetic Implications

Diseases affecting the aortic arch often require surgical intervention. Hypothermic circulatory arrest (HCA) enables a safe approach during open aortic arch surgeries. Additionally, HCA provides neuroprotection by reducing cerebral metabolism and oxygen requirements. However, HCA comes with significant risks (eg, neurologic dysfunction, stroke, and coagulopathy), and the cardiac anesthesiologist must completely understand the surgical techniques, possible complications, and management strategies.

A Strategy for Minimizing Circulatory Arrest Duration in Complex Aortic Arch Procedures

Background and Objectives: Aortic arch pathologies represent a surgical challenge. The challenge is partly due to the necessity of complex cerebral, visceral, and myocardial protection measures. Aortic arch surgery generally requires a significant duration of circulatory arrest, which includes deep hypothermia levels with the associated sequelae. This retrospective observational study shows the feasibility of a strategy that reduces circulatory arrest duration and eliminates the need for deep hypothermia during the procedure. Materials and Methods: Between January 2022 and January 2023, 15 patients (n = 15) with type A aortic dissection underwent total arch replacement with a frozen elephant trunk. Cardiopulmonary bypass and organ perfusion were established via arterial lines in the right axillary artery and one of the femoral arteries. In the latter vessels, a y-branched arterial cannula was used (ThruPort^TM₎, allowing for endo-clamping of the stent part of the frozen elephant trunk with a balloon and subsequent perfusion of the lower body. Results: Applying this modified perfusion technique, circulatory arrest time could be reduced to a mean of 8.1 ± 4.2 min, and surgery was performed at a mean lowest body temperature of 28.9 ± 2.3 °C. The mean ICU and hospital stays were 18.3 ± 13.7 days and 23.8 ± 11.7 days, respectively. The rate for 30-day survival was 100%. Conclusions: By applying our modified perfusion technique, the circulatory arrest duration was below ten minutes. As a consequence, deep hypothermia could be avoided, and surgery could be performed at moderate hypothermia. Future studies will have to show whether these changes may be translated into a clinical benefit for our patients.

The application of modular multifunctional left heart bypass circuit system integrated with ultrafiltration in thoracoabdominal aortic aneurysm repair

Open thoracoabdominal aortic aneurysm (TAAA) repair is a complex and challenging operation with a high incidence of serious complications, and high perioperative mortality and morbidity. Left heart bypass (LHB) is a circulatory support system used to perfuse the distal aorta during TAAA operation, and the advantages of LHB include guaranteeing distal perfusion, reducing the use of heparin, and diminishing the risk of bleeding and postoperative neurological deficits. In China, the circuit for TAAA repair is deficient, and far from the perfusion requirements. We designed a modular multifunctional LHB circuit for TAAA repair. The modular circuit consisted of cannulation pipelines, functional consumables connection pipelines, and accessory pipelines. The accessory pipelines make up lines for selective visceral perfusion and kidney perfusion, suckers and rapid infusion. The circuit can be assembled according to surgical requirements. The ultrafilter and heat exchanger are integrated into the circuit to fulfill the basic demands of LHB. The LHB circuit also has pipelines for selective visceral perfusion to the celiac artery and superior mesenteric artery and renal perfusion pipelines. Meanwhile, the reserved pipelines facilitate the quick switch from LHB to conventional cardiopulmonary bypass (CPB). The reserved pipelines reduce the time of reassembling the CPB circuit. Moreover, the rapid infusion was integrated into the LHB circuit, which can rapid infusion when massive hemorrhage during the open procedures such as exposure and reconstruction of the aorta. The ultrafiltration can diminish the consequent hemodilution of hemorrhage and rapid infusion. A hemoperfusion cartridge also can be added to reduce the systemic inflammatory during operation. The circuit can meet the needs of LHB and quickly switch to conventional CPB. No oxygenator was required during LHB, which reduce the use of heparin and reduce the risk of bleeding. The heat exchanger contributes to temperature regulation; ultrafiltration, arterial filter, and rapid-infusion facilitated the blood volume management and are useful to maintain hemodynamic stability. This circuit made the assembly of the LHB circuit more easily, and more efficient, which may contribute to the TAAA repair operation performed in lower volume centers easily. 26 patients who received TAAA repair under the modular multifunctional LHB from January 2018-March 2022 were analyzed, and we achieved acceptable clinical outcomes. The in-hospital mortality and 30-day postoperative mortality were 15.4%, and the postoperative incidences of paraparesis (4%), stroke (4%), and AKI need hemodialysis (12%) were not particularly high, based on the limited patients sample size in short research period duration.

Perioperative Outcomes for Radical Nephrectomy and Level III-IV Inferior Vena Cava Tumor Thrombectomy in Patients with Renal Cell Carcinoma

OBJECTIVES

This study examined the characteristics, intraoperative, and postoperative course of patients undergoing inferior vena cava tumor thrombectomy for metastatic renal cell carcinoma.

DESIGN

A single-center case series that reported demographic data and intraoperative and postoperative outcomes for patients with renal cell carcinoma undergoing inferior vena cava thrombectomy.

SETTING

This investigation was performed at a large quaternary referral center.

PARTICIPANTS

Adult patients (age ≥18) admitted to the authors' hospital from January 1, 2005, to March 10, 2017, undergoing inferior vena cava thrombectomy for level III and IV renal cell carcinoma.

INTERVENTIONS

No interventions were performed.

MEASUREMENTS AND MAIN RESULTS

Sixty-five patients who met the inclusion criteria were identified, with 31 patients diagnosed with level III and 34 with level IV renal cell carcinoma. Patients with level IV tumors were significantly more likely to have greater intraoperative blood loss, had longer surgical duration and hospital stays, and had more frequently required blood products, pressors, and cardiopulmonary bypass intraoperatively. Intraoperative transesophageal echo was more frequently used in level IV thrombectomy compared to level III (91.2% v 67.7%). Of patients with level IV thrombus, 41.2% developed postoperative atrial fibrillation compared to only 3.2% with level III thrombus. The 30-day mortality was 4.6% for both groups.

CONCLUSIONS

Patients undergoing inferior vena cava tumor thrombectomy for renal cell carcinoma had more complex intraoperative and postoperative courses with level IV compared to level III tumor thrombus.

Association between Functional Parameters of Coagulation and Conventional Coagulation Tests in the Setting of Fluid Resuscitation with Balanced Crystalloid or Gelatine: A Secondary Analysis of an In Vivo Prospective Randomized Crossover Study

Functional point-of-care tests (POCTs) have evolved into useful tools for diagnosing disorders of blood coagulation and fibrinolysis. We aimed to describe the in vivo association between standard and functional parameters of coagulation and fibrinolysis in the setting of acute hemodilution induced by an infusion of balanced crystalloid or synthetic gelatine solutions. This prospective randomized crossover in vivo study included healthy male volunteers aged 18–30 years. Enrolled participants were randomly assigned to receive either the Optilyte^® or Geloplasma^® infusion. Laboratory analysis included conventional coagulation parameters and rotational thromboelastometry (ROTEM) assays. A total of 25 healthy Caucasian males were included. ROTEM viscoelastic assays presented moderate to strong correlations with conventional coagulation tests, regardless of the fluid type utilized. Irrespectively of the extent of hemodilution, significant correlations remained unaffected. The strongest associations were found between the ROTEM clot formation and clot strength and the fibrinogen concentration and platelet count, and between the ROTEM clotting time and the APTT and PT. This in vivo experimental study in healthy male volunteers demonstrated that ROTEM may be used as a credible alternative to standard laboratory tests to assess blood coagulation and fibrinolysis in the setting of fluid resuscitation with both crystalloid and colloid solutions. The study was registered online in the ClinicalTrials.gov database (NCT05148650).

In Vivo Effects of Balanced Crystalloid or Gelatine Infusions on Functional Parameters of Coagulation and Fibrinolysis: A Prospective Randomized Crossover Study

Prudent administration of fluids helps restore or maintain hemodynamic stability in the setting of perioperative blood loss. However, fluids may arguably exacerbate the existing coagulopathy. We sought to investigate the influence of balanced crystalloid and synthetic gelatine infusions on coagulation and fibrinolysis in healthy volunteers. This prospective randomized crossover study included 25 males aged 18–30 years. Infusions performed included 20 mL/kg of a balanced crystalloid solution (Optilyte^®) or 20 mL/kg of gelatine 26.500 Da (Geloplasma^®) in a random order over a period of 2 weeks. Laboratory analysis included conventional coagulation parameters and rotational thromboelastometry (ROTEM) assays. We confirmed a decrease in fibrinogen concentration and the number of platelets, and prolongation of PT after infusions. Compared to baseline values, differences in the ROTEM assays’ results after infusions signified the decrease in coagulation factors and fibrinogen concentration, causing impaired fibrin polymerization and clot structure. The ROTEM indicator of clot lysis remained unaffected. In the case of both Optilyte^® and Geloplasma^®, the results suggested relevant dilution. Gelatine disrupted the process of clot formation more than balanced crystalloid. Infusions of both crystalloid and saline-free colloid solutions causing up to 30% blood dilution cause significant dilution of the coagulation factors, platelets, and fibrinogen. However, balanced crystalloid infusion provides less infusion-induced coagulopathy compared to gelatine.

Recombinant Activated Factor VII in Aortic Surgery for Patients Under Hypothermic Circulatory Arrest

Purpose

We aimed to identify the risk factors of critical bleeding and investigate the safety of recombinant activated factor VII (rFVIIa) in aortic surgery under hypothermic circulatory arrest (HCA).

Patients and Methods

The present single-center retrospective study compared the baseline characteristics of 144 patients who underwent aortic surgery under HCA at our institute. Among the total cohort of 144 patients, 42 received rFVIIa (rFVIIa group), while the remaining 102 patients did not (non-rFVIIa group). Perioperative bleeding and transfusions, postoperative 30-day mortality, and adverse events (AEs) were analyzed in 29 propensity score-matched pairs.

Results

Before surgery, the rFVIIa group demonstrated a greater number of shocks (p=0.019), higher JapanSCORE II mortality rate (p=0.033), low platelet count (p=0.015) and fibrinogen (p<0.001) level, prolonged activated partial thromboplastin time (aPTT) (p=0.005) and prothrombin time international normalized ratio (PT-INR) (p=0.006), and longer aortic cross clamp time (p=0.049). Postoperative bleeding, transfusion, 30-day mortality, and AEs were comparable between the groups both in the entire-unmatched cohort and propensity score matching cohort.

Conclusion

Preoperative shock, higher JapanSCORE II mortality rates, low platelet and fibrinogen levels, prolonged aPTT and PT-INR, and longer aortic clamping time might be risk factors for excessive bleeding and indicate the need for rFVIIa treatment. The present study suggests that rFVIIa can be safely used to address critical and continuous bleeding in spite of adequate transfusion and supplementation of other coagulation factors in aortic surgery under HCA, without an increase in 30-day mortality and AEs.

Hypothermia Induced Impairment of Platelets: Assessment With Multiplate vs. ROTEM—An In Vitro Study

Introduction: This experimental in vitro study aimed to identify and characterize hypothermia-associated coagulopathy and to compare changes in mild to severe hypothermia with the quantitative measurement of rotational thromboelastometry (ROTEM) and multiple-electrode aggregometry (MULTIPLATE).

Methods: Whole blood samples from 18 healthy volunteers were analyzed at the target temperatures of 37, 32, 24, 18, and 13.7°C with ROTEM (ExTEM, InTEM and FibTEM) and MULTIPLATE using the arachidonic acid 0.5 mM (ASPI), thrombin receptor-activating peptide-6 32 µM (TRAP) and adenosine diphosphate 6.4 µM (ADP) tests at the corresponding incubating temperatures for coagulation assessment.

Results: Compared to baseline (37°C) values ROTEM measurements of clotting time (CT) was prolonged by 98% (at 18°C), clot formation time (CFT) was prolonged by 205% and the alpha angle dropped to 76% at 13.7°C (p < 0.001). At 24.0°C CT was prolonged by 56% and CFT by 53%. Maximum clot firmness was only slightly reduced by ≤2% at 13.7°C. Platelet function measured by MULTIPLATE was reduced with decreasing temperature (p < 0.001): AUC at 13.7°C −96% (ADP), −92% (ASPI) and −91% (TRAP).

Conclusion: Hypothermia impairs coagulation by prolonging coagulation clotting time and by decreasing the velocity of clot formation in ROTEM measurements. MULTIPLATE testing confirms a linear decrease in platelet function with decreasing temperatures, but ROTEM fails to adequately detect hypothermia induced impairment of platelets.

Hypothermic circulatory arrest does not induce coagulopathy in vitro

Hypothermic circulatory arrest (HCA) is an essential procedure during aortic surgery to protect organs; however, hypothermia is believed to cause coagulopathy, which is a major fatal complication. This study aimed to clarify the impact of hypothermia on coagulation by eliminating clinical biases in vitro. In the hypothermic storage study, blood samples from five healthy volunteers were stored at 37 ℃ (group N) for 3 h or at 20 ℃ for 2 h, followed by 1 h of rewarming at 37 ℃ (group H). Thromboelastography was performed before and after 3 h of storage. In the mock circulation loop (MCL) study, blood samples were placed in the MCL and (a) maintained at 37 ℃ for 4 h (group N, n = 5), or (b) cooled to 20 ℃ to simulate HCA with a 0.1 L/min flow rate for 3 h and then rewarmed to 37 ℃ (group H, n = 5). The total MCL duration was 4 h, and the flow rate was maintained at 1 L/min, except during HCA. Blood samples collected 15 min after the beginning and end of MCL were subjected to standard laboratory tests and rotational thromboelastometry analyses. Hypothermia had no impact on coagulation in both the hypothermic storage and MCL studies. MCL significantly decreased the platelet counts and clot elasticity in the INTEM and EXTEM assays; however, there was no effect on fibrinogen contribution measured by FIBTEM. Hypothermia does not cause irreversible coagulopathy in vitro; however, MCL decreases coagulation due to the deterioration of platelets.

The David Operation Offers Shorter Hemostasis Time Than the Bentall in Case of Acute Aortic Dissection Type A

Background

The aim of the present study was to compare the clinical outcome of the David operation and the Bentall operation in patients with Stanford type A acute aortic dissection (AADA) from the viewpoint of hemostasis.

Methods

Between April 2016 and April 2020, 235 patients underwent emergent surgery for AADA. Of them, 38 patients required aortic root replacement (ARR: The David operation 17, the Bentall operation 21). The mean age was 59.3±12.6 years. In the present series, the David operation was the first choice for relatively young people, and the Bentall operation was performed for relatively elderly patients and cases in which valve-sparing seemed impossible.

Results

Between the David and the Bentall group, the 30-day mortality rate did not differ significantly. However, hemostasis time (144.6±50.3 vs. 212.5±138.1 min, p=0.047), defined as the interval from the cessation of cardio-pulmonary bypass (CPB) to the end of the operation, and total operation time (477.8±85.7 vs. 578.3±173.6 min, p=0.027) were significantly shorter in the David group than in the Bentall group, and the amount of blood transfusion was less in the David group than in the Bentall group (red blood cells: 3.5±3.6 vs. 9.2±5.9 units, p=0.013; fresh frozen plasma: 4.1±4.7 vs 9.4±5.1 units, p=0.002; platelet concentrate: 33.2±11.3 vs 42.2±12.0 units, p=0.025).

Conclusion

David operation offers a shorter hemostasis time and consequently shorter operation time than the Bentall operation in the setting of AADA, probably due to double suture lines, despite its surgical complexity.

Surgical Treatment of an Innominate Artery Aneurysm Using Near-Infrared Spectroscopy for Cerebral Monitoring: A Case Report

Innominate artery aneurysms are challenging for surgeons to treat because of the requirement for brain protection during surgery. In innominate artery aneurysms, the endovascular approach does not require cardiopulmonary bypass, but patients who can be treated using this approach are limited in number, and the long-term results of endovascular treatment are unclear. Here, we report our experience of successfully treating a patient with an innominate artery aneurysm using near-infrared spectroscopy without cardiopulmonary bypass support or hypothermic circulatory arrest.

Which factors have a great impact on coagulopathy and hemostatic impairment after cardiopulmonary bypass in cardiovascular surgery? An analysis based on rotational thromboelastometry

OBJECTIVES

This study aimed to investigate which factors have a great impact on coagulopathy after cardiopulmonary bypass (CPB) using rotational thromboelastometry (ROTEM).

METHODS

Ninety-eight patients undergoing cardiovascular surgery using CPB were enrolled. Data of amplitude 10 min after clotting time (A10) of ROTEM measured routinely before and after CPB were retrospectively collected. ROTEM has some assays by which we can evaluate the capacity of extrinsic coagulation (EXTEM), intrinsic coagulation (INTEM), fibrin polymerization (FIBTEM), and the effect of heparin (HEPTEM). The platelet component, defined as PLTEM, can be calculated by subtracting FIBTEM from EXTEM. Age, sex, total plasma volume, pre-CPB A10, lowest body temperature, in-out balance during CPB, intraoperative bleeding amount, and type of pumps were considered as possible factors. Univariate and multivariate analyses were performed for the rate of change of A10.

RESULTS

The change rate of each A10 had a significant negative correlation with bleeding amount (p < 0.01 for EXTEM, p < 0.01 for INTEM, p = 0.02 for FIBTEM, p < 0.01 for PLTEM). Female sex was a significant contributive predictor for the greater decline of EXTEM (p < 0.01) and INTEM (p < 0.01), positive balance for EXTEM (p < 0.01), FIBTEM (p = 0.01), and PLTEM (p < 0.01), long CPB time for INTEM (p = 0.01), centrifugal pump for FIBTEM (p < 0.01), and large pre-CPB A10 for PLTEM (p < 0.01).

CONCLUSION

In perioperative hemostatic management using ROTEM, attention should be given to the effects of these multiple factors.

Prepump autologous blood collection is associated with reduced intraoperative transfusions in aortic surgery with circulatory arrest: A propensity score-matched analysis

OBJECTIVE

To evaluate the effect of autologous whole blood (AWB) collection on intraoperative/postoperative allogeneic blood transfusion rate in complex aortic surgery with hypothermic circulatory arrest.

METHODS

This retrospective study included adults who underwent aortic surgery with hypothermic circulatory arrest at a single institution between 2014 and 2019. Out of 509 cases (414 patients), 110 (22%) received the AWB protocol. We performed propensity-score matching, including 35 preoperative and procedural variables, which resulted in 95 well-matched pairs, to compare outcomes in patients who received AWB protocol versus those who did not. Study outcomes were percentage of patients who received transfusion of allogeneic blood products intraoperatively and postoperatively.

RESULTS

Mean volume of collected autologous blood was 826 ± 263 mL. Intraoperatively, fewer AWB patients received red blood cell concentrate (33% vs 49%; P = .02), plasma (35% vs 62%; P = .0002), platelets (61% vs 81%; P = .003), and cryoprecipitate (43% vs 56%; P = .08) compared with non-AWB patients. During the entire hospital stay, the differences in transfusion rate between the 2 groups were: red blood cells (58% vs 62%; P = .6), plasma (49% vs 66%; P = .01), platelets (72% vs 82%; P = .09), and cryoprecipitate (56% vs 63%; P = .3).

CONCLUSIONS

Pre-pump autologous blood collection may reduce the need for intraoperative transfusion of allogenic non-red-cell blood products in patients undergoing complex aortic surgery with hypothermic circulatory arrest. A larger study is needed to clarify the influence of this association on patient outcomes and resource utilization.