Investigation of the Association between Bilateral Selective Anterograde Cerebral Perfusion and Postoperative Ischemic Stroke in Obese Patients with Emergency Surgery for Acute Type A Aortic Dissection.

Background and objectives: The relationship between cerebral perfusion and new postoperative ischemic stroke in obese patients is not well defined. The aim of this study was to investigate the association between selective bilateral anterograde cerebral perfusion and new postoperative ischemic stroke in obese patients with emergency surgery for acute type A aortic dissection. Materials and methods: A total of 292 patients with emergency surgery for acute type A aortic dissection were included in this study. Patients with hemorrhagic stroke or ischemic stroke with severe neurological dysfunction at admission that were not candidates for surgery; patients who died in the first 48 h after intensive care admission and patients with incomplete medical records were excluded. Results: The mean age was 59.42 ± 10.68 years and the mean Euroscore was 9.12 ± 1.63. Obesity was present in 76.4%, the incidence of new postoperative ischemic stroke was 27.5%, and the postoperative mortality rate was 26.7%. The mean cardiopulmonary bypass time was 206.81 ± 75.48 min, the aortic cross-clamp time was 118.2 ± 46.42 min, and 90% of cases required cerebral perfusion. The mean cerebral perfusion time was 30.8 ± 24.41 min. Obese patients had a higher frequency of in-hospital death (p = 0.009), smoking (p = 0.036), hypertension (p = 0.023), left common carotid artery dissection (p < 0.001), right common carotid artery dissection (p = 0.029), femoral artery cannulation (p = 0.026), aortic root replacement (p = 0.009), aortic valve replacement (p = 0.005) and early reintervention for bleeding (p = 0.004). Using logistic regression, selective bilateral anterograde cerebral perfusion over 40 min in obese patients was independently associated with new postoperative ischemic stroke (OR = 2.35; 95%CI = 1.36-4.86; p = 0.021). Conclusions: A patient-tailored strategy for cerebral perfusion should be considered in obese patients, considering the high atheromatous burden of the supra-aortic vessels in these patients and the potential risk of atheromatous embolization associated with this technique.

Cardiac surgery-associated acute kidney injury and perioperative plasma viscosity: is there a relationship?

Plasma viscosity (PV) is a key factor in microcirculatory flow resistance and capillary perfusion during hemodilution, we hypothesized a possible relationship between cardiac surgery-associated acute kidney injury (CSA-AKI) and PV. We conducted a prospective, observational, single-center study on 50 adult cardiac surgery patients with cardiopulmonary bypass (age 64 years, male sex 80%, baseline serum creatinine 1.04 mg/dL). We assessed perioperative characteristics, management, short-term outcomes, blood analysis, PV, serum creatinine, and diuresis. CSA-AKI was identified using KDIGO criteria. Data were collected at 10 time points during the first perioperative week. CSA-AKI occurred in 17 patients (34%): 12 (24%) stage 1, 1 (2%) stage 2, and 4 (8%) stage 3. Most patients (88%) developed CSA-AKI within 48 h post-surgery. Patients with CSA-AKI had higher body mass index (BMI), more frequent chronic kidney disease (CKD), and lower hemoglobin and hematocrit levels. The median baseline PV for the entire cohort was 1.50 cP on EDTA and 1.37 cP on citrate. No significant differences in PV levels were found between patients with CSA-AKI and normal kidney function, both at baseline and at the 48-h. Logistic and Cox regression analyses showed no significant relationship between PV and CSA-AKI. However, CSA-AKI was related to increased BMI, lower hemoglobin and hematocrit levels, and pre-existing CKD. The present study found no significant association between PV and CSA-AKI. Nevertheless, more research is needed to validate this finding and to investigate the role of PV in other clinical settings.

Factors Associated with Newly Developed Postoperative Neurological Complications in Patients with Emergency Surgery for Acute Type A Aortic Dissection.

Background and Objectives: Postoperative neurological complications (NCs) are an important cause of mortality in patients with acute type A aortic dissection (ATAAD). The aim of the study was to determine the association between intraoperative risk factors and newly developed postoperative NCs in patients after emergency surgery for ATAAD. Materials and Methods: A total of 203 patients requiring emergency surgery were included in the study. Patients with preoperative neurological dysfunction, deceased on the operating table or within the first 48 h after intensive care admission, with uncertain postoperative neurologic status or with incomplete records were excluded. Results: Mean age was 57.61 ± 12.27 years. Hyperlipidemia was the most frequent comorbidity (69%). A bicuspid aortic valve was present in 12.8% of cases, severe acute aortic regurgitation was present in 29.1% of patients, and cardiac tamponade was present in 27.1% of cases. The innominate artery was the most frequently dissected supra-aortic artery in 27.1% of cases. In 65% of cases, the primary entry tear was at the level of the ascending aorta. The incidence of newly developed postoperative NCs was 39.4%. The most common surgical technique performed was supra-coronary ascending aorta and hemiarch replacement, in 53.2% of patients. Using logistic regression, cardiopulmonary bypass time (OR = 1.01; 95% CI = 1.01-1.02; p < 0.001), aortic cross-clamp time over 3 h (OR = 2.71, 95% CI = 1.43-5.14, p = 0.002) and cerebral perfusion time (OR = 1.02; 95% CI = 1.002-1.03; p = 0.027) were independently associated with newly developed postoperative NCs. Conclusions: Based on the results of the study, all efforts should be made to reduce operative times. Using a simple surgical technique, like the supra-coronary ascending aorta and hemiarch technique, whenever possible, and using a simpler technique for cerebral perfusion like unilateral cerebral perfusion via the right axillary artery, could reduce operating times.

Perioperative trajectory of plasma viscosity: A prospective, observational, exploratory study in cardiac surgery.

OBJECTIVE: Plasma viscosity is one of the critical factors that regulate microcirculatory flow but has received scant research attention. The main objective of this study was to evaluate plasma viscosity in cardiac surgery with respect to perioperative trajectory, main determinants, and impact on outcome. METHODS: Prospective, single center, observational study, including 50 adult patients undergoing cardiac surgery with cardiopulmonary bypass between February 1, 2020 and May 31, 2021. Clinical perioperative characteristics, short term outcome, standard blood analysis, plasma viscosity, total proteins, and fibrinogen concentrations were recorded at 10 distinct time points during the first perioperative week. RESULTS: The longitudinal analysis showed that plasma viscosity is strongly influenced by proteins and measurement time points. Plasma viscosity showed a coefficient of variation of 11.3 ± 1.08 for EDTA and 12.1 ± 2.1 for citrate, similarly to total proteins and hemoglobin, but significantly lower than fibrinogen (p < .001). Plasma viscosity had lower percentage changes compared to hemoglobin (RANOVA, p < .001), fibrinogen (RANOVA, p < .001), and total proteins (RANOVA, p < .001). The main determinant of plasma viscosity was protein concentrations. No association with outcome was found, but the study may have been underpowered to detect it. CONCLUSION: Plasma viscosity had a low coefficient of variation and low perioperative changes, suggesting tight regulation. Studies linking plasma viscosity with outcome would require large patient cohorts.

Perioperative Trajectory of Haemoglobin, Predictors of Blood Transfusion and Tailoring Targets for Patient Blood Management Interventions: A Single-centre, Retrospective Study of Non-emergent Cardiac Surgery Patients.

Background: Anaemia and blood transfusion are two independent contributing factors to perioperative morbidity in cardiac surgery. While preoperative treatment of anaemia has been shown to improve outcomes, in real life, logistical difficulties remain substantial, even in high-income countries. The adequate trigger for transfusion in this population remains controversial, and there is a wide variability in transfusion rates among centres. Objectives: To assess the impact of preoperative anaemia on perioperative transfusion in elective cardiac surgery,todescribe the perioperative trajectory of haemoglobin (Hb), to stratify outcomes based on preoperative presence of anaemia and to identify predictors of perioperative blood transfusion. Materials: and Methods: We included a retrospective cohort of consecutive patients who underwent cardiac surgery with cardiopulmonary bypass in a tertiary centre of cardiovascular surgery. Recorded outcomes included hospital and intensive care unit (ICU) length of stay (LOS), surgical re-exploration due to bleeding, packed red blood cell (PRBC) transfusion pre-, intra- and postoperatively. Other record perioperative variables were preoperative chronic kidney disease, duration of surgery, use of rotation thromboelastometry (ROTEM) and cell saver, and fresh frozen plasma (FFP) and platelet (PLT) transfusion. Hb values were recorded at four distinct time points: Hb1 - at hospital admission, Hb2 - last Hb recorded preoperatively, Hb3 - first Hb recorded postoperatively and Hb4 - at hospital discharge. We compared the outcomes between anaemic and non-anaemic patients. Transfusion was decided by the attending physician on a case-by-case basis. Results: Of the 856 patients operated during the selected period, 716 underwent non-emergent surgery and 710 were included in the analysis. Also, 40.5% (n = 288) of patients were anaemic preoperatively (Hb <13 g/dl); 369 patients (52%) were transfused PRBCs, with differences found between anaemic and non-anaemic patients regarding the percentage of transfused patients perioperatively (71.5% vs 38.6%, p < 0.001) and in the total median number of units transfused (2 [IQR 0-2] vs 0 [IQR 0-1], p <0.001). We built a multivariate model, and logistic regression analysis showed that preoperative Hb <13 g/dl (odds ratio [OR] 3.462 [95% CI 1.766-6.787]), female sex (OR 3.224 [95% CI 1.648-6.306]), age (1.024 per year [95% CI 1.0008-1.049]), hospital LOS (OR 1.093 per day of hospitalisation [95% CI 1.037-1.151]) and FFP transfusion (OR 5.110 [95% CI 1.997-13.071]) are associated with PRBC transfusion. Conclusions: Untreated preoperative anaemia leads to more transfusion in elective cardiac surgery patients, both as a ratio of transfused patients and as the number of units of PRBCs per patient, and this is associated with an increased use in FFP.