Does moderate hypothermia really carry less bleeding risk than deep hypothermia for circulatory arrest? A propensity-matched comparison in hemiarch replacement

Does Higher Temperature During Moderate Hypothermic Circulatory Arrest Increase the Risk of Paraplegia in Acute DeBakey I Aortic Dissection Patients?

BACKGROUND

In this study, we sought to assess the safety of high-moderate (24.1-28.0°C) and low-moderate (20.1-24.0°C) systemic hypothermia during circulatory arrest (MHCA) in patients with acute DeBakey I aortic dissection (DeBakey I AAD), particularly concerning spinal cord protection.

METHODS

From 2009 to 2020, 1759 patients with DeBakey I AAD who underwent frozen elephant trunk and total arch replacement surgery at a tertiary centre were divided into preoperative malperfusion (viscera, spinal cord, or lower extremities) and nonmalperfusion subgroups. The baseline differences were balanced with the use of propensity score matching. Prognoses were compared between those who were subjected to high-MHCA (nasopharyngeal temperature 24.1-28.0°C) and low-MHCA (nasopharyngeal temperature 20.1-24.0°C).

RESULTS

In the nonmalperfusion subgroup (n = 1389), 469 pairs of matched patients showed lower in-hospital mortality and incidence of acute kidney injury in the high-MHCA group than in the low-MHCA group: in-hospital mortality 7.0% vs 10.2% (P = 0.01); acute kidney injury, 57.1% vs 64.6% (P < 0.01). The duration of mechanical ventilation was shorter in the high-MHCA group than that in the low-MHCA group (P = 0.03). No significant difference in the incidence of paraplegia was observed between the 2 groups. In the malperfusion subgroup (n = 370), 112 pairs of matched patients showed a higher incidence of paraplegia in the high-MHCA group than in the low-MHCA group (15.9% vs 6.5%; P = 0.04).

CONCLUSIONS

The safety of high-MHCA, a commonly used temperature management strategy during aortic arch surgery, was recognised in most patients with DeBakey I AAD. However, among patients with preoperative distal organ malperfusion, low-MHCA may be more appropriate owing to an increased risk of postoperative paraplegia associated with high-MHCA.

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.

Clinical outcomes of mild versus moderate hypothermic circulatory arrest with antegrade cerebral perfusion in adult aortic arch surgery: A systematic review and meta-analysis

OBJECTIVES

In adult aortic arch surgery, moderate hypothermic circulatory arrest (HCA) with selective antegrade cerebral perfusion (SACP) (MoHACP) is widely used, but the application of mild HCA with SACP (MiHACP) is still controversial. This meta-analysis aimed to compare clinical outcomes using MiHACP or MoHACP.

METHODS

Studies comparing outcomes of MiHACP or MoHACP in adult aortic arch surgery were searched from four databases from inception through April 2022. Primary outcomes were postoperative permanent neurological deficit (PND), temporary neurological deficit (TND), and mortality. Secondary outcomes included other common complications. Meta-analysis was conducted using a random-effects model in all cases.

RESULTS

Eleven comparative studies were included, with 1555 patients in MiHACP group and 1499 patients in MoHACP group, and the mean HCA temperature were 29.4°C and 24.8°C, respectively. Postoperative PND, TND, mortality, paraplegia, dialysis, tracheotomy, reexploration for bleeding, and chest tube drainage volume were comparable in the two groups (p > 0.05). Ventilator time, intensive care unit and in-hospital length of stay were shorter in MiHACP group (p < 0.05). Outcomes were also comparable or had some benefits in MiHACP group when subgroup analyses were conducted according to hemiarch or total arch replacement, unilateral or bilateral SACP, HCA time, emergency aortic dissection surgery, and concomitant procedure.

CONCLUSION

The present meta-analysis showed acceptability of MiHACP in adult aortic arch surgery. Results need to be taken with caution as moderate risk of bias and very low quality of evidence were observed in this meta-analysis. Randomized controlled trials are needed for further analysis.

The use of blood and blood products in aortic surgery is associated with adverse outcomes

OBJECTIVE

To report long-term outcomes after deep hypothermic circulatory arrest (DHCA) with or without perioperative blood or blood products.

METHODS

All patients who underwent proximal aortic surgery with DHCA from 2011 to 2018 were propensity matched according to baseline characteristics. Primary outcomes included short- and long-term mortality. Stratified Cox regression analysis was performed for significant associations with survival.

RESULTS

A total of 824 patients underwent aortic replacement requiring circulatory arrest. After matching, there were 224 patients in each arm (transfusion and no transfusion). All baseline characteristics were well matched, with a standardized mean difference (SMD) <0.1. Preoperative hematocrit (41.0 vs 40.6; SMD = 0.05) and ejection fraction (57.5% vs 57.0%; SMD = 0.08) were similar between the no transfusion and blood product transfusion cohorts. Rate of aortic dissection (42.9% vs 45.1%; SMD = 0.05), hemiarch replacement (70.1% vs 70.1%; SMD = 0.00), and total arch replacement (21.9% vs 23.2%; SMD = 0.03) were not statistically different. Cardiopulmonary bypass and cross-clamp time were higher in the blood product transfusion cohort (P < .001). Operative mortality (9.4% vs 2.7%; P = .003), stroke (7.6% vs 1.3%; P = .001), reoperation rate, pneumonia, prolonged ventilation, and dialysis requirements were significantly higher in the transfusion cohort (P < .001). In stratified Cox regression, transfusion was an independent predictor of mortality (hazard ratio, 2.62 [confidence interval, 1.47-4.67]; P = .001). One- and 5-year survival were significantly reduced for the transfusion cohort (P < .001).

CONCLUSIONS

In patients who underwent aortic surgery with DHCA, perioperative transfusions were associated with poor outcomes despite matching for preoperative baseline characteristics.

Prevention and management of difficult hemostasis in acute type A aortic dissection repair

Postoperative bleeding after surgery for acute aortic dissection is one of the most common complications and has an important influence on mortality and morbidity. Therefore, various methods have been introduced to prevent or manage postoperative bleeding. In this article, we investigated the causes of bleeding after surgery for acute aortic dissection, and introduce appropriate transfusion or pharmacologic treatment, topical hemostatic agents, and local compressive maneuver to manage it.

Unsolved issues in acute type A aortic dissection

Surgery for acute type A aortic dissection remains challenging with considerable mortality and morbidity despite the remarkable advances in this field. Particularly, surgical outcomes of acute type A aortic dissection are known to be associated with the hospital volume. The optimal cerebral protective method and extent of surgery have been long-standing controversies in acute type A aortic dissection surgery. Given that data from randomized trial are not available and future trials are also unrealistic, observational data based on large registry or meta-analyses may alternatively provide reliable and reasonable evidence. With regard to neuroprotective methods for arch repair, currently available observational data strongly suggest that there are no overt superiority among unilateral-antegrade cerebral perfusion, bilateral-antegrade cerebral perfusion, and retrograde cerebral perfusion, by which their availabilities are still open in real clinical practices depending on institutional preferences. When deciding the extent of arch repair in acute DeBakey type I aortic dissection, multiple factors should be considered altogether such as aortic anatomic characteristics as well as patient's risk profiles for optimizing early safety and late aortic longevity.

Quiescence-inducing neurons-induced hypometabolism ameliorates acute kidney injury in a mouse model mimicking cardiovascular surgery requiring circulatory arrest

Objectives

Acute kidney injury is a serious complication after cardiovascular surgery requiring circulatory arrest. It is reported that mice can be induced into a hibernation-like hypometabolic state by stimulating a specific neuron located at the hypothalamus (quiescence-inducing neurons-induced hypometabolism [QIH]). Here, we investigated the efficacy of QIH for the amelioration of acute kidney injury in an experimental circulatory arrest using a transgenic mouse model.

Methods

We genetically prepared mice in which QIH can be conditionally induced (QIH-ready mice). Mice were divided into 4 groups (n = 6 for each): QIH-ready normothermia (QN), QIH-ready hypothermia (QH), control normothermia (CN), and control hypothermia (CH). After induction of QIH, left thoracotomy and descending aorta crossclamping were conducted. After reperfusion, we collected kidneys and evaluated histologic changes and serum biochemical markers, specifically neutrophil gelatinase-associated lipocalin and cystatin C, indicating early kidney injury.

Results

Normothermia showed higher tubular injury scores than those in hypothermia (QN vs QH [P = .0021] and CN vs CH [P < .001]). QN exhibited lower neutrophil gelatinase-associated lipocalin and cystatin C levels than those in CN (neutrophil gelatinase-associated lipocalin: CN vs QN: 1.51 ± 0.71 vs 0.82 ± 0.32; P = .0414 and cystatin C: 1.48 ± 0.39 vs 0.71 ± 0.26; P = .0015). There was no significant difference between QN and QH.

Conclusions

QIH partly ameliorated acute kidney injury in a mouse ischemia model even in normothermia. QIH might be a promising approach to achieving sufficient kidney protection without hypothermic circulatory arrest in the future.

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.

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 New York experience of open arch surgery

BACKGROUND

Aortic arch repair has undergone constant evolution since its inception with improving outcomes. A sizeable number of competing techniques and strategies have been described, with no single optimal method endorsed by the surgical community. We describe our experience with open aortic arch repair in a high-volume center.

METHODS

We queried our aortic database for consecutive patients undergoing aortic arch repair from 1997-2021. Those undergoing hemiarch repair were compared to those undergoing total arch repair. Outcomes were compared using multivariate analysis.

RESULTS

Of 1308 patients undergoing aortic arch repair, 953 underwent hemiarch repair and 355 underwent total arch repair. The median age was 69 [interquartile ratio 58-76] and 61.7% were men. Hemiarch patients more frequently hade aortic dissection (28.5 vs 11.8%, P < 0.001) and urgent or emergent procedure status (45.1 vs 30.4%, P < 0.001). Overall operative mortality was 2.7% and significantly higher in the hemiarch group (3.5 vs 0.6%, P=0.007). No difference in the incidence of major adverse events (MAE) including myocardial infarction, cerebrovascular accident, new need for dialysis, re- exploration for bleeding, and tracheostomy was found between the two groups. Multivariate analysis found diabetes, urgent or emergent procedure status, preoperative renal dysfunction, New York Heart Association class III/IV symptoms, and connective tissue disease to be independent predictors of MAE.

CONCLUSIONS

Retrograde cerebral perfusion with deep hypothermic circulatory arrest is safe and effective, with no appreciable difference in neurologic outcomes when comparing hemiarch to total arch strategies. Rates of mortality and MAE compare favorably with strategies utilizing antegrade cerebral perfusion.

Optimal circulatory arrest temperature for aortic hemiarch replacement with antegrade brain perfusion

OBJECTIVE

This study sought to identify the optimal temperature for moderate hypothermic circulatory arrest in patients undergoing elective hemiarch replacement with antegrade brain perfusion.

METHODS

The Society of Thoracic Surgeons adult cardiac surgery database was queried for elective hemiarch replacements using antegrade brain perfusion for aneurysmal disease (2014-2019). Generalized estimating equations and restricted cubic splines were used to determine the risk-adjusted relationships between temperature as a continuous variable and outcomes.

RESULTS

Elective hemiarch replacement with antegrade brain perfusion occurred in 3898 patients at 374 centers with a median nadir temperature of 24.9 °C (first quartile, third quartile = 22.0 °C, 27.5 °C) and median circulatory arrest time of 19 minutes (first quartile, third quartile = 14.0 minutes, 27.0 minutes). After adjustment for comorbidities, circulatory arrest time, and individual surgeon, patients cooled between 25 and 28 °C had an early survival advantage compared with 24 °C, whereas those cooled between 21 and 23 °C had higher risks of mortality compared with 24 °C. A nadir temperature of 27 °C was associated with the lowest risk-adjusted odds of mortality (odds ratio, 0.62; 95% confidence interval, 0.42-0.91). A nadir temperature of 21 °C had the highest risk of mortality (odds ratio, 1.4; 95% confidence interval, 1.13-1.73). Risk of experiencing a major morbidity was elevated in patients cooled between 21 and 23 °C, with the highest risk occurring in patients cooled to 21 °C (odds ratio, 1.12; 95% confidence interval, 1.01-1.24).

CONCLUSIONS

For patients with aneurysmal disease undergoing elective hemiarch with antegrade brain perfusion, circulatory arrest with a nadir temperature of 27 °C confers the greatest early survival benefit and smallest risk of postoperative morbidity.

Modified Technique for Retrograde Cerebral Perfusion during Hemiarch Aortic Replacement

Background  Uncertainty remains regarding the optimal method of brain protection for procedures that require repair or replacement of the aortic arch. We examined the early outcomes of a technique for brain protection in patients undergoing partial aortic arch (hemiarch) replacement that involves deep hypothermic circulatory arrest (DHCA) and retrograde cerebral perfusion (RCP) of cold blood from the superior vena cava toward the end of the arrest interval.

Methods  During a recent 15-year interval, 520 patients underwent elective or urgent/emergent ascending aortic and hemiarch replacement as an isolated (47 patients) or combined (473 patients) procedure employing DHCA (mean nasopharyngeal temperature at circulatory arrest, 17.1°C and mean duration, 19.3 minutes) supplemented with RCP of cold blood from the superior vena cava toward the end of the arrest interval (mean, 6.7 minutes). The mean age of the patients was 59.5 years, and 65% were male.

Results  The in-hospital and 30-day mortality rates were 1.2% (six patients). Seven patients (1.4%) sustained a stroke and 19 patients (3.7%) had transient neurologic dysfunction that completely resolved by the time of hospital discharge. Four patients (0.77%) developed postoperative renal failure requiring dialysis. Twenty-one patients (4%) required ventilator support for >48 hours and five patients (0.96%) required a tracheostomy. The median hospital length of stay was 6 days.

Conclusion  DHCA with a brief interval of RCP is a safe and effective technique for brain protection during hemiarch aortic replacement. RCP reduces the duration of brain ischemia and permits removal of particulate matter and air from the arterial circulation.

Risk factor analysis of clinical outcomes of total aortic arch replacement and frozen elephant trunk with aortic balloon occlusion

Background

Total aortic arch replacement (TAR) with frozen elephant trunk (FET) requires hypothermic circulatory arrest (HCA) for 20 min, which increases the surgical risk. We invented an aortic balloon occlusion (ABO) technique that requires 5 min of HCA on average to perform TAR with FET and investigated the possible merit of this new method in this study.

Methods

This retrospective study included consecutive patients who underwent TAR and FET (consisting of 130 cases of ABO group and 230 cases of conventional group) in Fuwai Hospital between August 2017 and February 2019. In addition to the postoperative complications, the alterations of blood routine tests, alanine transaminase (ALT) and aspartate transaminase (AST) during in-hospital stay were also recorded.

Results

The 30-day mortality rates were similar between ABO group (4.6%) and conventional group (7.8%, P = 0.241). Multivariate analysis showed ABO reduced postoperative acute kidney injury (23.1% vs. 35.7%, P = 0.013) and hepatic injury (12.3% vs. 27.8%, P = 0.001), and maintained similar cost to patients (25.5 vs. 24.9 kUSD, P = 0.298). We also found that AST was high during intensive care unit (ICU) stay and recovered to normal before discharge, while ALT was not as high as AST in ICU but showed a rising tendency before discharge. The platelet count showed a rising tendency on postoperative day 3 and may exceed the preoperative value before discharge.

Conclusions

The ABO achieved the surgical goal of TAR with FET with an improved recovery process during the in-hospital stay.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01643-3.

Surgery for renal cell carcinoma extending to the right atrium in Japanese institutions: Focusing on cardiopulmonary bypass with or without deep hypothermic circulatory arrest

OBJECTIVES

To evaluate the outcomes of Japanese patients with renal cell carcinoma undergoing surgery for tumor thrombus invading the right atrium.

METHODS

We retrospectively evaluated 23 patients who underwent extracorporeal circulation-assisted surgery at two institutions. Perioperative outcomes and survival rates were evaluated and compared between two groups of patients, which were set according to the use or not of deep hypothermic circulatory arrest. Data on systemic treatments were assessed.

RESULTS

The median age was 64 years; the majority of patients were fit according to the Charlson Comorbidity Index. Five (21.7%) patients had at least one distant metastasis, and 17 (73.9%) received systemic therapy. A total of 16 (69.6%) patients underwent deep hypothermic circulatory arrest. Baseline characteristics were comparable between groups. Patients who underwent deep hypothermic circulatory arrest had a non-significant reduction in blood loss compared with those who did not undergo this procedure (1866.0 vs 3513.0 mL, P = 0.102). The complication rate, both of any grade (43.8% vs 71.4%, P = 0.215) and grade ≥3 (6.3% vs 28.6%, P = 0.162), tended to be lower in patients who underwent deep hypothermic circulatory arrest. The mean 90-day mortality rate was 8.7%, with no difference among groups (6.3% vs 14.3%, respectively; P = 0.545). The overall median cancer-specific and overall survival were both 64.4 months, and did not differ between groups.

CONCLUSIONS

Renal cell carcinoma patients undergoing extracorporeal circulation-assisted surgery and systemic therapy for right atrial tumor thrombus have acceptable long-term survival rates. Outcomes are comparable regardless of the use of deep hypothermic circulatory arrest.

Aortic valve repair with a newly approved geometric annuloplasty ring in patients undergoing proximal aortic repair: early results from a single-centre experience

OBJECTIVES

Aortic insufficiency (AI) is common in patients with proximal aortic disease, but limited options exist to facilitate aortic valve repair (AVr) in this population. This study reports 'real-world' early results of AVr using newly FDA-approved trileaflet and bicuspid geometric annuloplasty rings for patients with AI undergoing proximal aortic repair (PAR) in a single referral centre.

METHODS

All patients undergoing AVr with a rigid internal geometric annuloplasty ring (n = 47) in conjunction with PAR (ascending +/- root +/- arch) were included. Thirty-six patients underwent AVr with a trileaflet ring, and 11 patients underwent AVr with a bicuspid ring. The rings were implanted in the subannular position, and concomitant leaflet repair was performed if required for cusp prolapse identified after ring placement.

RESULTS

The median age was 58 years [interquartile range (IQR) 46-70]. PAR included supracoronary ascending replacement in 26 (55%) patients and remodelling valve-sparing root replacement with selective sinus replacement in 20 (42%) patients. Arch replacement was performed in 38 (81%) patients, including hemi-arch in 34 patients and total arch in 4 patients. There was no 30-day/in-hospital mortality. Preoperative AI was 3-4+ in 37 (79%) patients. Forty-one (87%) patients had zero-trace AI on post-repair transoesophageal echocardiography, and 6 patients had 1+ AI. The median early post-repair mean gradient was 13 mmHg (IQR 5-20). Follow-up imaging was available in 32 (68%) patients at a median of 11 months (IQR 10-13) postsurgery. AI was ≤1+ in 97% of patients with 2+ AI in 1 patient. All patients were alive and free from aortic valve reintervention at last follow-up.

CONCLUSIONS

Early results with geometric rigid internal ring annuloplasty for AVr in patients undergoing PAR appear promising and allow a standardized approach to repair with annular diameter reduction and cusp plication when needed. Longer-term follow-up will be required to ensure the durability of the procedure.

Short-Periods of Pre-Warming in Laparoscopic Surgery. A Non-Randomized Clinical Trial Evaluating Current Clinical Practice

Background: Pre-warming prevents perioperative hypothermia. We evaluated the current clinical practice of pre-warming and its effects on temperature drop and postoperative complications; Methods: This prospective, observational pilot study examines clinical practice in a tertiary hospital on 99 patients undergoing laparoscopic urological surgery. Pre-warming was performed in the pre-anesthesia room. Patients were classified into three groups: P 0 (non-prewarmed), P 5–15 (pre-warming 5–15 min) and P > 15 (pre-warming 15–30 min). Tympanic temperature was recorded in the pre-anesthesia room, prior to anesthesia induction, and in the PACU. Esophageal temperature was recorded intraoperatively. The occurrence of shivering, pain intensity, length of stay in PACU, and postoperative complications during hospital stay were also recorded; Results: After pre-warming, between-group difference in body temperature was higher in P > 15 than in P 0 (0.4 °C, 95% CI 0.14–0.69, p = 0.004). Between P 5–15 and P 0 difference was 0.2 °C (95% CI 0.04–0.55, p = 0.093). Temperature at the end of surgery was higher in pre-warmed groups [mean between-group difference 0.5 °C (95% CI 0.13–0.81, p = 0.007) for P 5–15; 0.9 °C (95% CI 0.55–1.19, p < 0.001) for P > 15]. Pain and shivering was less common in pre-warmed groups. Postoperative transfusions and surgical site infections were lower in P > 15; Conclusion: Short-term pre-warming prior to laparoscopic urological surgery decreased temperature perioperative drop and postoperative complications.

Mild hypothermic circulatory arrest with selective cerebral perfusion in open arch surgery

Background

This study aimed to evaluate whether the use of mild hypothermic circulatory arrest (HCA) with selective cerebral perfusion (SCP) in open arch procedure provides comparable perioperative results to moderate HCA for patients with dissected or degenerative arch pathologies.

Methods

Between January 2017 and September 2020, a total of 88 consecutive patients (mean age 47±11 years, 71 males) underwent open arch repair under a single surgeon at our institution with mild or moderate systemic hypothermia assisted by unilateral or bilateral SCP. Patients were divided into groups according to the nasopharyngeal temperature at the beginning of HCA: a moderate HCA group (n=47, 53.4%) and a mild HCA group (n=41, 46.6%). The postoperative mortality, morbidity, and visceral organ functions between these groups were analyzed retrospectively.

Results

Compared to the moderate HCA group, the mild HCA group had a significantly higher core temperature (nasopharynx: 24.4±0.8 vs. 28.5±2, P<0.001; bladder 25.9±0.9 vs. 30±1.2, P<0.001), and the incidence of major adverse events (MAE) in this group was markedly lower (21.3% vs. 4.9%, P=0.031). No differences were identified between the two groups refer to in-hospital mortality, permanent neurological deficit (PND), temporary neurological deficit (TND), and paraplegia (8.5% vs. 2.4%, P=0.366; 8.5% vs. 0, P=0.120; 6.4% vs. 7.3%, P=1.0; 4.3% vs. 2.4%, P=1.0, respectively). In the moderate HCA group, 6 patients (12.8%) developed acute renal failure needing replacement therapy, which did not occur in the mild HCA group (P=0.028). The duration of ventilator support and intensive care unit stay was shorter in the mild HCA group, as well as a decreased volume of drainage during the first 24 h and reduced platelet transfusion.

Conclusions

The preliminary results of the mild HCA group with SCP applied in open arch repair, mainly in total arch replacement (TAR) and stented elephant trunk (SET) implantation for aortic dissection, were satisfactory. Furthermore, comparable inferior outcomes were obtained with mild HCA compared with that of the conventional moderate HCA strategy. These encouraging surgical and postoperative results favor this more aggressive hypothermia strategy in open arch repair.

Effect of Deep Hypothermic Circulatory Arrest Versus Moderate Hypothermic Circulatory Arrest in Aortic Arch Surgery on Postoperative Renal Function: A Systematic Review and Meta-Analysis

Background

Moderate hypothermic circulatory arrest (MHCA) has been widely used in aortic arch surgery. However, the renal function after MHCA remains controversial. We performed a systematic review and meta‐analysis direct comparison of the postoperative renal function of MHCA versus deep hypothermic circulatory arrest (DHCA) in aortic arch surgery.

Methods and Results

We searched PubMed, Embase, and the Cochrane Library for postoperative renal function after aortic arch surgery with using MHCA and DHCA, published from inception to January 31, 2020. The primary outcome was renal failure. Secondary outcomes were the need for renal therapy and other major postoperative outcomes. The random‐effects model was used for all comparisons to pool the estimates. A total of 14 observational studies with 4142 patients were included. Compared with DHCA, MHCA significantly reduced the incidence of renal failure (odds ratio [OR], 0.76; 95% CI, 0.61–0.94; P=0.011; I²=0.0%) and the need of renal replacement (OR, 0.68; 95% CI, 0.48–0.97; P=0.034; I²=0.0%). Subgroup analysis showed that when the hypothermic circulatory arrest time was <30 minutes, the incidence of renal failure in MHCA group was significantly lower than that in DHCA group (OR, 0.73; 95% CI, 0.54–0.99; P=0.040; I²=1.1%), whereas an insignificant difference between 2 groups when hypothermic circulatory arrest time was >30 minutes (OR, 0.76; 95% CI, 0.51–1.13; P=0.169; I²=17.3%).

Conclusions

MHCA compared with DHCA reduces the incidence of renal failure and the need for renal replacement.

Registration

URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42020169348.

Renal protective effect of the aortic balloon occlusion technique in total arch replacement with frozen elephant trunk

Background

Organ dysfunction caused by hypothermic circulatory arrest continues to concern surgeons. The aortic balloon occlusion (ABO) technique can significantly shorten the circulatory arrest time in total arch replacement with frozen elephant trunk (TAR with FET). This study aims to analyze the renal protective effect of the ABO technique and to analyze the predictors of acute kidney injury (AKI) and continuous renal replacement therapy (CRRT) after TAR with FET.

Methods

Between August 2017 and September 2018, 247 patients who underwent TAR with FET were divided into ABO and moderate hypothermic circulatory arrest (MHCA) groups. The primary endpoint was postoperative AKI defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Multivariable logistic analysis was used to identify the predictors of AKI and CRRT after TAR with FET.

Results

With the application of the ABO technique, the circulatory arrest time was significantly shortened (ABO 4, IQR: 3-6 vs. MHCA 18, IQR: 16-20, P<0.001). Meanwhile, surgeons safely set the lowest nasopharyngeal temperature at a higher grade (ABO 28.1, IQR: 27.4-28.5 vs. MHCA 24.7, IQR: 24.1-25.1, P<0.001). The peak serum creatinine (SCr) values within 48 hours after the surgery was lower in the ABO group than in the MHCA group (ABO 124, IQR: 97-173 vs. MHCA 146, IQR: 108-221, P=0.008). The distribution of AKI grade according to the KDIGO criteria differed between the two groups (P=0.04): more patients in the ABO group were free from AKI (Grade 0) than patients in the MHCA group (33% vs. 23.1%), and the proportion of patients with high-grade AKI (Grades 2 and 3) in the ABO group was lower than that in the MHCA group (21% vs. 32%). The ABO technique was associated with reduced potential for AKI, but was not protective for CRRT.

Conclusions

The ABO technique significantly shortened the circulatory arrest time and safely elevated temperature, and provided better renal protection in patients undergoing TAR with FET. The ABO technique did not reverse the need for CRRT, nor did it reduce mortality or major adverse events.

Hypothermic circulatory arrest induced coagulopathy: rotational thromboelastometry analysis

Objectives

Hypothermic circulatory arrest (HCA) has been considered to cause coagulopathy during cardiac surgery. However, coagulopathy associated with HCA has not been understood clearly in details. The objective of this study is to analyze the details of coagulopathy related to HCA in cardiac surgery by using rotational thromboelastometry (ROTEM).

Methods

We retrospectively analyzed 38 patients who underwent elective cardiac surgery (HCA group = 12, non-HCA group = 26) in our hospital. Blood samples were collected before and after cardiopulmonary bypass (CPB). Standard laboratory tests (SLTs) and ROTEM were performed. We performed four ROTEM assays (EXTEM, INTEM, HEPTEM and FIBTEM) and analyzed the following ROTEM parameters: clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF) and maximum clot elasticity (MCE). The amount of perioperative bleeding, intraoperative transfusion and perioperative data were compared between the HCA and non-HCA group.

Results

Operation time and hemostatic time were significantly longer in the HCA group, whereas CPB time had no difference between the groups. The amount of perioperative bleeding and intraoperative transfusion were much higher in the HCA group. SLTs showed no difference between the groups both after anesthesia induction and after protamine reversal. In ROTEM analysis, MCE contributed by platelet was reduced in the HCA group, whereas MCE contributed by fibrinogen had no difference.

Conclusion

Our study confirmed that the amount of perioperative bleeding and intraoperative transfusion were significantly higher in the HCA group. ROTEM analysis would indicate that clot firmness contributed by platelet component is reduced by HCA in cardiac surgery.

Moderate and deep hypothermic circulatory arrest has a comparable effect on acute kidney injury after total arch replacement with frozen elephant trunk procedure in type A aortic dissection

OBJECTIVES

The goal was to investigate the prevalence of acute kidney injury (AKI) after total arch replacement with frozen elephant trunk procedure, which was achieved by antegrade cerebral perfusion and moderate hypothermic circulatory arrest (MHCA) or deep hypothermic circulatory arrest (DHCA) among patients with type A aortic dissection.

METHODS

Overall, 627 adult type A aortic dissection patients who underwent total arch replacement with frozen elephant trunk from January 2013 until December 2016 at Fuwai Hospital were divided into the DHCA (14.1-20.0°C) and MHCA (20.1-28.0°C) groups. Postoperative AKI as the primary outcome was compared using propensity-matched scoring.

RESULTS

Overall, 340 (54.2%) and 287 (45.8%) patients underwent DHCA and MHCA, respectively. The overall incidence of AKI was 75.4%. Age [odds ratio (OR) 1.02, 95% confidence interval (CI) 1.00-1.04; P = 0.022], body mass index (OR 1.06, 95% CI 1.01-1.12; P = 0.016), cardiopulmonary bypass duration (OR 1.01, 95% CI 1.00-1.01; P = 0.003) and hypertension history (OR 1.76, 95% CI 1.14-2.70; P = 0.010) were identified as independent risk factors for AKI onset with multivariable analysis. Postoperative AKI was not significantly different between the DHCA and MHCA groups regardless of the overall or propensity-matched cohort (overall data: P = 0.17; propensity score data: P = 0.88). Patients with MHCA experienced higher rates of postoperative stroke after propensity score analysis (DHCA 0.9% vs MHCA 3.7%; P = 0.034).

CONCLUSIONS

MHCA was not superior to DHCA in decreasing postoperative AKI. Thus, MHCA should not definitively replace DHCA.

Peri-procedural hemostasis disorders in surgical and transcatheter aortic valve implantation

Introduction

Despite their high effectiveness, surgical aortic valve replacement (AVR) and transcatheter aortic valve implantation (TAVI) are associated with substantial risk of bleeding. Although procedure-related hemostasis disorders might be crucial for safety of both procedures, the amount of data on the peri-procedural status of hemostasis in patients with aortic valve stenosis (AS) subjected to AVR and TAVI is negligible.

Aim

To investigate the profile of peri-procedural hemostasis in elderly patients with AS, subjected to aortic valve prosthesis implantation.

Material and methods

We performed a prospective analysis of global hemostasis using ROTEM thromboelastometry and platelet reactivity assessment using impedance aggregometry in 30 consecutive patients ≥ 70 years old subjected to AVR and TAVI. All tests were performed within 24 h before, directly and 24 h after the procedures.

Results

Surgical aortic valve replacement was characterized by transient hypofibrinogenemia and von Willebrand factor (vWF) depletion, which quickly recovered within 24 h after AVR. Transcatheter aortic valve implantation was characterized by substantial alteration of platelet function and vWF depletion with significant platelet reactivity impairment and increase in platelet sensitivity to antiplatelet agent, early after the procedure. TAVI-related hemostasis alterations were not recovered at 24 h after the procedure.

Conclusions

Surgical and transcatheter aortic valve replacement procedures are associated with substantial and diverse peri-procedural hemostasis disorders. Since hemostasis disorders related to TAVI are mainly characterized by impaired platelet function, early dual antiplatelet prophylaxis after TAVI requires careful consideration.

Deep Hypothermic Circulatory Arrest Does Not Show Better Protection for Vital Organs Compared with Moderate Hypothermic Circulatory Arrest in Pig Model

Background

Continued debates exist regarding the optimal temperature during hypothermic circulatory arrest in aortic arch repair for patients with type A aortic dissection. This study seeks to examine whether the use of moderate hypothermic circulatory arrest in a pig model provides comparable vital organ protection outcomes to the use of deep hypothermic circulatory arrest.

Methods

Thirteen pigs were randomly assigned to 30 minutes of hypothermic circulatory arrest without cerebral perfusion at 15°C (n = 5), 25°C (n = 5), and a control group (n = 3). The changes in standard laboratory tests and capacity for protection against apoptosis in different vital organs were monitored with different temperatures of hypothermic circulatory arrest management in pig model to determine which temperature was optimal for hypothermic circulatory arrest.

Results

There were no significant differences in the capacity for protection against apoptosis in vital organs between 2 groups (p > 0.05, respectively). Compared with the moderate hypothermic circulatory arrest group, the deep hypothermic circulatory arrest group had no significant advantages in terms of the biologic parameters of any other organs (p > 0.05).

Conclusions

Compared with deep hypothermic circulatory arrest, moderate hypothermic circulatory arrest is a moderate technique that has similar advantages with regard to the levels of biomarkers of injury and capacity for protection against apoptosis in vital organs.

Prevention of hemorrhagic complications during operations on the thoracic aorta

Aim. To assess the efficiency of guideline for the prevention of hemorrhagic complications in the early postoperative period.

Material and methods. In the period from 2008 to 2017, 166 patients with pathology of the thoracic aorta were operated. The patients were divided into 2 comparable groups: group 1 — patients with reconstructed aortic arch of the type “Hemiarch” (group “hemiarch”, n=90), group 2 — patients with fully reconstructed aortic arch (group “arch”, n=76). All operations were performed with artificial blood circulation, circulatory arrest with moderate hypothermia (25­28° C) and unilateral antegrade cerebral perfusion through the brachiocephalic trunk.

Results. The reconstructions of the thoracic aorta in patients of the “hemiarch” group were accompanied by significantly less period of artificial blood circulation (p=0,027), cardiac arrest period (p=0,012), duration of circulatory arrest (p=0,019), and duration of antegrade brain perfusion (p=0,021). The volume of discharge through the drainage was 350 [192;506] ml and 400 [250;723] ml in the “hemiarch” and “arch” groups, respectively (p=0,29). Patients of the “arch” group more often required transfusion of packed red cells (p=0,003), fresh frozen plasma (p=0,0006), platelet concentrate (p=0,002) in comparison with patients of the “hemiarch” group. At the same time, the frequency of bleeding requiring reoperation was comparable in both groups (5,6% versus 5,3%, p=0,969). The 30­day mortality also had no statistically significant differences in patients of the “hemiarch” and “arch” groups (3,3% versus 9,2%, p=0,119).

Conclusion. The frequency of hemorrhagic complications requiring reoperation in patients with a fully or partially reconstructed aortic arch does not have significant differences when using the guideline for preventing of hemorrhagic complications, which makes it possible to provide acceptable frequency of bleeding episodes and reoperations in the early postoperative period.

Low molecular weight heparin in surgical valve procedures: When and how much for an optimal prophylaxis?

BACKGROUND

Periprocedural antithrombotic prophylaxis in patients undergoing surgical valve procedures (SVP) is insufficiently investigated. Low molecular weight heparin (LMWH) has been considered as an alternative to unfractionated heparin (UFH). However, safety and efficacy of this prophylaxis strategy is unknown. This study aimed to investigate safety and efficacy of periprocedural LMWH prophylaxis and determine optimal dosage and timing for periprocedural cessation and initiation.

METHODS

The present study is a retrospective, single-center observational analysis of 388 patients who underwent SVP (valve replacement or valvuloplasty) between 2015 and 2016. In-hospital endpoints were bleeding, transfusions, reoperation due to bleeding, and thromboembolic events.

RESULTS

Giving the first dose of LMWH on the day of SVP was a risk factor for bleeding (OR 1.07; 95% CI 1.04-1.10; p < 0.001), transfusions (OR 1.04; 95% CI 1.01-1.07; p = 0.008) and reoperation due to bleeding (OR 1.20; 95% CI 1.12-1.28; p < 0.001), with > 40 mg/day as a predictor. A higher dosage of LMWH premedication was an independent risk factor for bleeding (OR 1.02; 95% CI 1.00-1.04; p = 0.03) and transfusion (OR 1.03; 95% CI 1.01-1.05; p = 0.01), with > 60 mg/day as a predictor for these events. LMWH dosed within 24 h prior to SVP increased the risk of transfusion (AUC 0.636; 95% CI 0.496-0.762; p = 0.04).

CONCLUSIONS

Bleeding is an important early concern after surgical valve procedures. Safety and efficacy of periprocedural prophylaxis with LMWH depends on dosage and the timing of its administration. The most optimal periprocedural prophylaxis in the SVP population appears to be LMWH in dosage of 40-60 mg/day, which is recommended for deep vein thrombosis prophylaxis, ceased at least one day before SVP.

Innominate Versus Axillary Artery Cannulation for the Hemiarch Repair

BACKGROUND

Innominate artery cannulation has gained some popularity over the last decade as an alternative to axillary artery cannulation for providing selective antegrade cerebral perfusion during repair of the ascending aorta and arch. Innominate artery cannulation provides several advantages including avoidance of an additional incision and use of a larger caliber artery to provide less resistance to high flow during bypass and selective antegrade cerebral perfusion. We hypothesize that these advantages make innominate artery cannulation superior to axillary artery cannulation as it can decrease operative times and potentially decrease blood loss.

METHODS

This was a single-center retrospective analysis of 206 patients who underwent hemiarch replacement between 2009 and 2017. All patients qualified including emergent cases. Groups were separated by mode of cannulation: axillary and innominate. Outcomes evaluated included cardiopulmonary bypass (CPB) time, cross-clamp time, circulatory arrest (CA) time, postoperative transfusions, intensive care unit length of stay, development of any neurological complications, end-organ failure, and mortality. Subgroup analysis was performed for elective and emergent cases.

RESULTS

Axillary and innominate artery cannulation accounted for 37% (n = 77) and 67% (n = 129) of cases, respectively. There was no difference in patient characteristics except for a higher incidence of renal disease in the axillary group (16% versus 6%, P = 0.05). More emergent cases were performed in the axillary group (61% versus 17%, P < 0.001). Innominate cases had shorter CPB times (189 versus 150 min, P < 0.001) and CA (22.5 versus 11 min, P < 0.001) times overall. In the elective subgroup, CA times were shorter for the innominate cases. However, the emergent subgroup displayed no difference in operative times. Less transfusions were given in the innominate group including units of red blood cells (2 [0-6] versus 0 [0-2], P < 0.001), units of platelets (2 [1-3] versus 1 [0-2], P = 0.001), and units of plasma (6 [2-9] versus 2 [0-4], P < 0.001). A similar trend was observed in the elective subgroup. No difference in transfusions was observed in the emergent subgroup. There was no statistical difference in remaining outcomes between cases of axillary and innominate cannulation in the combined, elective, and emergent groups.

CONCLUSIONS

Alternate cannulation strategies for open arch anastomoses are evolving with a trend toward using the innominate artery. These data suggest that innominate cannulation is at least equivalent to, and may be superior to, axillary cannulation. The innominate artery provides a larger conduit vessel for perfusion and this decrease in resistance to flow, allowing for faster cooling and rewarming, maybe why CPB times were lower in this group. Innominate cannulation is a safe and potentially advantageous technique for hemiarch repair.

Aortic arch repair under moderate hypothermic circulatory arrest with or without antegrade cerebral perfusion based on the extent of repair

Background

For aortic-arch repair, moderate hypothermic circulatory arrest (HCA) have shown favorable outcomes over conventional deep HCA when coupled with antegrade cerebral perfusion (ACP); however, recent studies have shown that ACP may not be essential when circulatory arrest time is less than 30 minutes. This study aims to evaluate the stratified arch repair strategy of moderate HCA with or without ACP based on the extent of procedure.

Methods

Consecutive 138 patients (63 female; mean age, 60.2±15.7 years) undergoing open arch repair due to acute aortic syndrome (n=69) or chronic aneurysm (n=69) from January 2012 through April 2017 were enrolled in this study. Stratified neuroprotective strategy was employed according to the extent of repair: hemi-arch repair (n=93) was performed under moderated HCA alone and total-arch repair (n=45) under moderate HCA combined with unilateral ACP.

Results

Median total circulatory arrest and total procedural times were 8.0 minutes [interquartile range (IQR), 6.0-10.0] and 233.0 minutes (IQR, 196.0-290.0 minutes), respectively in the hemi-arch group, and 25.0 minutes (IQR, 12.0-33.0 minutes) and 349.0 minutes (IQR, 276.0-406.0 minutes), respectively in the total-arch group. Early mortality occurred in 2 patients (1.4%) who underwent hemi-arch repair for acute aortic dissection. There was no permanent neurological injury, but 2 cases (1.4%) of temporary neurologic deficit in the hemi-arch group. Other complications included re-exploration for bleeding in 6 (4.3%), postoperative extracorporeal life support in 5 (3.6%) and new-dialysis in 6 (4.3%).

Conclusions

Stratified cerebral perfusion strategy using moderate hypothermia for aortic-arch surgery based on the extent of arch repair showed satisfactory safety and reasonable efficiency.