Operative risk and preoperative hematocrit in bypass graft surgery: Role of gender and blood transfusion

Sex-based disparities in ascending aortic aneurysm surgery outcomes: a comprehensive analysis of 1148 consecutive patients with propensity-score matching

BACKGROUND

Women undergoing cardiac surgery have been historically recognized to carry higher periprocedural mortality risk. We aimed to investigate the influence of sex on clinical presentation, perioperative, and long-term outcomes in patients who undergo surgery for ascending aortic aneurysm.

METHODS

We conducted a retrospective review of 1148 consecutive patients (380 [33.1%] female) who underwent thoracic aortic surgery under moderate hypothermic circulatory arrest for ascending aortic aneurysms between 2001 and 2021. Baseline and operative characteristics, in-hospital mortality, and survival were compared between male and female patients before and after propensity-score-matched (PSM) analysis.

RESULTS

Women were significantly older (median age: 69 [IQR: 63-75] vs. 67 [IQR: 58-73]; P < 0.001), while men had a higher prevalence of aortic valve stenosis, bicuspid valve and coronary artery disease at the time of surgery (P < 0.05). After PSM, EuroSCORE II (4.36 [2.68; 6.87] vs. 3.22 [1.85; 5.31]; p < 0.001), and indexed aortic diameter were significantly higher in female patients (2.94 [2.68; 3.30] vs. 2.58 [2.38; 2.81] cm/m2, p < 0.001). In the matched cohort, men were more likely to experience postoperative delirium (18.1% vs. 11.5%; P = 0.002), and postoperative neurological deficits (6.7% vs. 3.0%, P = 0.044),. Female patients were more likely to receive postoperative packed red blood cells (p = 0.036) and fresh frozen plasma (p = 0.049). In-hospital and 30-day mortality was similar between both groups. Long-term survival was comparable between both groups with 88% vs. 88% at 5 years, 76% vs. 71% at 10 years, and 59% vs. 47% at 15 years.

CONCLUSION

Female patients required more transfusions, while males had a higher incidence of postoperative delirium and neurological deficits. Differences in preoperative age and timing of surgery between the sexes could be attributed to variations in comorbidity profiles and the greater prevalence of concomitant surgery indications in males.

Differences among sexes in presentation and outcomes in acute type A aortic dissection repair

OBJECTIVE

Female sex is a known risk factor in most cardiac surgery, including coronary and valve surgery, but unknown in acute type A aortic dissection repair.

METHODS

From 1996 to 2018, 650 patients underwent acute type A aortic dissection repair; 206 (32%) were female, and 444 (68%) were male. Data were collected through the Cardiac Surgery Data Warehouse, medical record review, and National Death Index database.

RESULTS

Compared with men, women were significantly older (65 vs 57 years, P < .0001). The proportion of women and men inverted with increasing age, with 23% of patients aged less than 50 years and 65% of patients aged 80 years or older being female. Women had significantly less chronic renal failure (2.0% vs 5.4%, P = .04), acute myocardial infarction (1.0% vs 3.8%, P = .04), and severe aortic insufficiency. Women underwent significantly fewer aortic root replacements with similar aortic arch procedures, shorter cardiopulmonary bypass times (211 vs 229 minutes, P = .0001), and aortic crossclamp times (132 vs 164 minutes, P < .0001), but required more intraoperative blood transfusion (4 vs 3 units) compared with men. Women had significantly lower operative mortality (4.9% vs 9.5%, P = .04), especially in those aged more than 70 years (4.4% vs 16%, P = .02). The significant risk factors for operative mortality were male sex (odds ratio, 2.2), chronic renal failure (odds ratio, 3.4), and cardiogenic shock (odds ratio, 6.8). The 10-year survival was similar between sexes.

CONCLUSIONS

Physicians and women should be cognizant of the risk of acute type A aortic dissection later in life in women. Surgeons should strongly consider operations for acute type A aortic dissection in women, especially in patients aged 70 years or more.

Impact of Preoperative Hematocrit, Body Mass Index, and Red Cell Mass on Allogeneic Blood Product Usage in Adult Cardiac Surgical Patients: Report From a Statewide Quality Initiative

OBJECTIVE

The study aims were to evaluate current blood transfusion practice in cardiac surgical patients and to explore associations between preoperative anemia, body mass index (BMI), red blood cell (RBC) mass, and allogeneic transfusion.

DESIGN

Multicenter retrospective study.

SETTING

Academic and non-academic centers.

PARTICIPANTS AND INTERVENTIONS

After Institutional Review Board approval, 26,499 patients who underwent coronary artery bypass grafting ± valve replacement/repair between 2011 and 2019 were included from the Maryland Cardiac Surgery Quality Initiative database. Patients were stratified into BMI categories (<25, 25 to <30, and ≥30 kg/m²), and a multivariable logistic regression model was fit to determine if preoperative hematocrit, BMI, and RBC mass were associated independently with allogeneic transfusion.

RESULTS

Preoperative anemia was found in 55.4%, and any transfusion was administered to 49.3% of the entire cohort. Females and older patients had lower BMI and RBC mass. Increased RBC and cryoprecipitate transfusions occurred more frequently after surgery in the lower BMI group. After adjustments, increased transfusion was associated with a BMI <25 relative to a BMI ≥30 at an odds ratio (OR) of 1.26 (95% confidence interval [CI]: 1.08-1.39). For each 1% increase in preoperative hematocrit, transfusion was decreased by 9% (OR: 0.91; 95% CI: 0.90-0.92). For every 500 mL increase in RBC mass, there was a 43% reduction of transfusion (OR: 0.57; 95% CI: 0.55-0.58).

CONCLUSIONS

Transfusion probability modeling based on calculated RBC mass eliminated sex differences in transfusion risk based on preoperative hematocrit, and may better delineate which patients may benefit from more rigorous perioperative blood conservation strategy.

Sex-specific risk factors for early mortality and survival after surgery of acute aortic dissection type a: a retrospective observational study

Background

Although gender-related disparities in cardiovascular surgery have been investigated extensively in the past decades, knowledge about the impact of gender on outcomes after surgery for acute aortic dissection type A (AADA) is sparse. This study investigated the impact of gender on early morbidity and mortality and follow-up outcome in patients after surgery for AADA and to analyze gender-related risk factors for 30-day mortality.

Methods

This retrospective study included 368 consecutive patients (male 65.8% vs. female 34.2%) undergoing surgery for AADA between 2001 and 2016 at our department. Survival was estimated by Kaplan-Meier curves. Risk factors for 30-day mortality were assessed by multivariable logistic regression and interaction analysis.

Results

Women were older (70.7 years vs. 60.6 years; p <  0.001) and showed a higher logistic EuroSCORE I (31.0% vs. 19.7%, p <  0.001). In the male group, a higher portion of smokers (27.6% vs. 16.0%, p = 0.015) and intraoperatively, more complex procedures and longer cardiopulmonary bypass (CPB) (171 min vs. 149 min, p = 0.001) and cross-clamping times (94 min vs. 85 min, p = 0.018) occurred. 30-day mortality was 19.0% in the female and 16.5% in the male group (p = 0.545). Predictive for 30-day mortality in both genders was intraoperative blood transfusion, while in the female group chronic obstructive pulmonary disease (COPD), peripheral arterial disease and preoperative intubation were predictive. Preoperative cardiopulmonary resuscitation and duration of CPB time were predictors only in males. Averaged follow-up time was 5.2 years and survival did not differ between genders, even if it was stratified by age over 70 years.

Conclusions

This analysis demonstrated a similar and satisfactory survival in both genders after surgical treatment of AADA. Women and men differed significantly in age, unadjusted and adjusted risk factors and complexity of surgical treatment, but gender itself was no risk factor for mortality. These results suggest that the decision-making for surgical treatment should not depend on gender, but that accounting for sex-specific risk factors rather than common risk factors may help to improve the outcome in both genders.

Adjusted preoperative variables to predict perioperative red blood cell transfusion in coronary artery bypass grafting

BACKGROUND

The variables for predicting blood transfusion perioperatively are not completely clear in coronary artery bypass grafting (CABG) patients.

OBJECTIVES

To construct a comprehensive model to predict perioperative RBC transfusion in patients undergoing isolated CABG using adjusted preoperative variables.

METHODS

Perioperative data of 1253 patients who underwent isolated CABG by the same surgical team were collected from April 2018 to March 2019. Logistic regression analyses were used to establish equations to construct two models for predicting intraoperative and postoperative RBC transfusions, respectively. All significant variables included in the two models were combined to form a comprehensive model to predict perioperative RBC transfusion. Area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the discriminatory power of the models.

RESULTS

The total RBC transfusion rate for CABG patients during hospitalization was 29.05%. The rate of intraoperative and postoperative RBC transfusions was 6.9% and 26.7%, respectively. Eight variables in a total of 30 risk factors constituted the intraoperative prediction model, 12 variables constituted the postoperative prediction model, and 13 variables for the combined model. The AUC of the three models were 0.87, 0.82, and 0.83, respectively, demonstrating moderate discriminatory power for RBC transfusion during the intraoperative, postoperative, and perioperative periods.

CONCLUSION

The comprehensive model combined with all variables of predicting intraoperative and postoperative RBC transfusion is feasible for predicting perioperative RBC transfusion.

Prediction of perioperative transfusions using an artificial neural network

BACKGROUND

Accurate prediction of operative transfusions is essential for resource allocation and identifying patients at risk of postoperative adverse events. This research examines the efficacy of using artificial neural networks (ANNs) to predict transfusions for all inpatient operations.

METHODS

Over 1.6 million surgical cases over a two year period from the NSQIP-PUF database are used. Data from 2014 (750937 records) are used for model development and data from 2015 (885502 records) are used for model validation. ANN and regression models are developed to predict perioperative transfusions for surgical patients.

RESULTS

Various ANN models and logistic regression, using four variable sets, are compared. The best performing ANN models with respect to both sensitivity and area under the receiver operator characteristic curve outperformed all of the regression models (p < .001) and achieved a performance of 70-80% specificity with a corresponding 75-62% sensitivity.

CONCLUSION

ANNs can predict >75% of the patients who will require transfusion and 70% of those who will not. Increasing specificity to 80% still enables a sensitivity of almost 67%. The unique contribution of this research is the utilization of a single ANN model to predict transfusions across a broad range of surgical procedures.

Sex-Specific Outcome after Ascending Aortic Surgery in Moderate Hypothermic Circulatory Arrest

BACKGROUND

Historically, female patients had worse outcome undergoing heart surgery. No recent data exist on gender-specific outcome after moderate hypothermic circulatory arrest (MHCA). The aim of this large retrospective analysis was to investigate gender disparity in patients undergoing elective surgery of ascending aorta in MHCA at 24°C.

METHODS

We conducted a retrospective review of 905 (33.3% female) cases of elective heart surgery in MHCA for ascending aortic aneurysm (90.9%) or severely calcified aorta (12.5%) between 2001 and 2015. Furthermore, 299 female and 299 male patients matched by propensity score were compared. Patients with dissection of the aorta were excluded.

RESULTS

Women were older (68.4 ± 9.9 vs. 65.8 ± 11.6 years; p = 0.002), had higher logistic EuroSCORE I (18.4 [11.7; 29.2] vs. 12.3% [7.4; 22.6]; p < 0.001), and significantly shorter cardiopulmonary bypass (CPB) time (132 [105; 175] vs. 150 [118; 192] minutes; p < 0.001), while mean MHCA time was longer (15 [13; 19] vs. 14 [12; 17] minutes; p = 0.003). Surgical procedures were less complex in women and they were treated more frequently by isolated supracoronary ascending aorta replacement (61 vs. 54%; p = 0.046). Postoperatively, men showed a higher incidence of neurologic complications (7.0 vs. 3.3%; p = 0.03). The 30-day mortality (women 4.9% vs. men 3.9%; p = 0.48) did not differ significantly, likewise after statistical matching (4.7 vs. 2.3%; p = 0.120). Age, CPB time, and blood transfusion, but not female gender, were risk factors for mortality in multivariable regression analysis.

CONCLUSION

This study supports the hypothesis that female gender is not associated with increased short-term mortality or perioperative adverse events in elective aortic surgery in MHCA.

Gender and intraoperative blood transfusion: analysis of 54,122 non-reoperative coronary revascularization procedures

Background:

Previous studies have shown that women undergoing isolated coronary artery bypass graft (CABG) surgery have an increased risk for postoperative morbidity and mortality when compared to men. Additionally, recent evidence suggests that blood transfusions are independently associated with an increased risk of adverse outcome.

Methods:

We evaluated gender differences in the risk of intraoperative red blood cell (RBC) transfusion during CABG surgery. Consecutive, non-reoperative CABG procedures performed across 196 institutions between April 2012 and May 2015 were retrospectively reviewed. Gender differences for intraoperative transfusion were evaluated with a multi-variable binary logistic regression model, adjusting for age, blood volume (Nadler formula to normalize for height and weight), body mass index, procedure acuity, net extracorporeal circuit prime volume, use of autologous priming, first hematocrit (Hct) in the operating room (OR), nadir Hct on cardiopulmonary bypass (CPB), volume added on CPB, ultrafiltration volume, urine output on CPB and procedure duration.

Results:

Among 54,122 patients (25.3% female), 21.6% (n = 11,701) received a RBC transfusion. Compared to men, female patients were older (66 years vs. 64 years, p<0.001), had lower blood volumes (4.3L vs. 5.6L, p<0.001) and a lower preoperative Hct (32.9% vs. 37.2%, p<0.001). Transfusion rates were three-fold higher in women versus men (45.1% vs. 13.7%, p<0.001). After adjustment for independent predictors of intraoperative transfusion, women remained at increased risk versus men (OR = 1.30, 95%CI = 1.19−1.43).

Conclusions:

Women have an increased risk of intraoperative RBC transfusion versus men. After adjusting for height and weight, much of this risk is due to gender differences in preoperative Hct and blood volume; however, a residual significant risk remained after adjustment. Perfusion strategies aimed at gender differences may minimize unnecessary transfusions. Future study on the impact of gender on transfusion practice in cardiac surgery is warranted.

Gender disparities in red blood cell transfusion in elective surgery: a post hoc multicentre cohort study

OBJECTIVES

A post hoc gender comparison of transfusion-related modifiable risk factors among patients undergoing elective surgery.

SETTINGS

23 Austrian centres randomly selected and stratified by region and level of care.

PARTICIPANTS

We consecutively enrolled in total 6530 patients (3465 women and 3065 men); 1491 underwent coronary artery bypass graft (CABG) surgery, 2570 primary unilateral total hip replacement (THR) and 2469 primary unilateral total knee replacement (TKR).

MAIN OUTCOME MEASURES

Primary outcome measures were the number of allogeneic and autologous red blood cell (RBC) units transfused (postoperative day 5 included) and differences in intraoperative and postoperative transfusion rate between men and women. Secondary outcomes included perioperative blood loss in transfused and non-transfused patients, volume of RBCs transfused, perioperative haemoglobin values and circulating red blood volume on postoperative day 5.

RESULTS

In all surgical groups, the transfusion rate was significantly higher in women than in men (CABG 81 vs 49%, THR 46 vs 24% and TKR 37 vs 23%). In transfused patients, the absolute blood loss was higher among men in all surgical categories while the relative blood loss was higher among women in the CABG group (52.8 vs 47.8%) but comparable in orthopaedic surgery. The relative RBC volume transfused was significantly higher among women in all categories (CABG 40.0 vs 22.3; TKR 25.2 vs 20.2; THR 26.4 vs 20.8%). On postoperative day 5, the relative haemoglobin values and the relative circulating RBC volume were higher in women in all surgical categories.

CONCLUSIONS

The higher transfusion rate and volume in women when compared with men in elective surgery can be explained by clinicians applying the same absolute transfusion thresholds irrespective of a patient's gender. This, together with the common use of a liberal transfusion strategy, leads to further overtransfusion in women.