Blood Conservation Strategies Can Be Applied Safely to High-Risk Complex Aortic Surgery

Perioperative Transfusion and Mortality for Cardiovascular Surgery: A Cohort Study Based on Population in Republic of Korea

Objective:This study aimed to evaluate the rate of transfusion for cardiovascular surgeries between 2010 and 2019 in Republic of Korea and the association between blood transfusion and postoperative mortality. Methods: Data were extracted from the National Health Insurance Service database in Republic of Korea. This study includes adult patients who underwent cardiovascular surgery between 1 January 2010 and 31 December 2019. The endpoints were in-hospital mortality and the 1-year all-cause mortality. Results: The analysis included 62,794 cases, with transfusions used in 88.8% of cases. Multivariable logistic regression revealed that older age, comorbidities, hospital admission through the emergency room, aortic procedures (versus coronary artery bypass grafting), cardiopulmonary bypass, repeat procedures, and supportive therapies during the intensive care (extracorporeal membrane oxygenation and mechanical ventilation) were risk factors for blood transfusion. Female sex was associated with a lower risk of transfusion. Perioperative blood transfusion was associated with a 6.87-fold increased risk of in-hospital mortality (odds ratio [OR]: 6.87, 95% confidence interval [CI]: 3.95, 11.93; p < 0.001) and a 3.20-fold increased risk of 1-year all-cause mortality (OR: 3.35, 95% CI: 2.75, 3.93; p < 0.001). Conclusions: Blood transfusion is used at a high rate in cardiovascular surgeries, and it was associated with increases in the risk of in-hospital and 1-year all-cause mortality. However, these correlations should be viewed with caution as emergent phenomena rather than causative. Understanding factors associated with the need for blood transfusion can assist surgeons in predicting the outcomes of cardiovascular surgery and in tailoring procedures as needed to optimize outcomes.

Blood transfusion in aortic root surgery impairs midterm survival

Objective

To evaluate the effect of perioperative allogeneic packed red blood cell (RBC) transfusion during aortic root replacement.

Method

We reviewed patients undergoing aortic root replacement at our institution between March 2014 and April 2020. In total, 760 patients underwent aortic root replacement, of whom 442 (58%) received a perioperative RBC transfusion. Propensity score matching was used to account for baseline and operative differences resulting in 159 matched pairs. All-cause mortality was assessed with Kaplan-Meier curves. Data were obtained from our institutional Society of Thoracic Surgeons database and chart review.

Results

After propensity score matching, the RBC-transfused and -nontransfused groups were similar for all preoperative characteristics. Cardiopulmonary bypass time, crossclamp time, and lowest operative temperature were similar between the transfused and nontransfused groups (standardized mean difference <0.05). RBC transfusion was associated with more frequent postoperative ventilation greater than 24 hours (36/159 [23%] vs 19/159 [12%]; P = .01), postoperative hemodialysis (9/159 [5.7%] vs 0/159 [0%]; P = .003), reoperation for mediastinal hemorrhage (9/159 [5.7%] vs 0/159 [0%]; P = .003), and longer intensive care unit and hospital length of stay (3 vs 2 days and 8 vs 6 days respectively; P < .001). Thirty-day operative mortality after propensity score matching was similar between the cohorts (1.9%; 3/159 vs 0%; P = .2), and 5-year survival was reduced in the RBC transfusion cohort (90.2% [95% confidence interval, 84.1%-96.7%] vs 97.1% [95% confidence interval, 92.3%-100%] P = .035).

Conclusions

Aortic root replacement frequently requires RBC transfusion during and after the operation, but even after matching for observed preoperative and operative characteristics, RBC transfusion is associated with more frequent postoperative complications and reduced midterm survival.

Improving Patient Blood Management Programs: An Implementation Science Approach

Organized patient blood management (PBM) programs function in numerous hospitals and health systems around the world contributing to improved patient outcomes as well as increased patient engagement, decreased resource use, and reductions in health care costs. PBM "programming" ranges from the implementation of single strategies/initiatives to comprehensive programs led by dedicated clinicians and PBM committees, employing the use of multiple PBM strategies. Frontline health care professionals play an important role in leading, implementing, operationalizing, measuring, and sustaining successful PBM programs. In this article, we provide practical implementation guidance to support key clinical, administrative, leadership, and structural elements required for the safe and comprehensive delivery of care in PBM programs at the local level.

Transfusion in Root Replacement for Aortic Dissection: STS Adult Cardiac Surgery Database Analysis

BACKGROUND

Transfusion in acute aortic syndromes has been studied in a limited fashion. We sought to describe contemporary transfusion practice for root replacement in acute (Stanford) type A aortic dissection (ATAAD).

METHODS

The STS Adult Cardiac Surgery Database was interrogated to identify patients who underwent primary aortic root replacement for ATAAD (July 2014 - June 2017). Patients (n = 1558) were stratified by type of root replacement. Multivariate regression was used to determine those variables associated with transfusion and postoperative morbidity.

RESULTS

Transfusion was required in 90.5% of cases (n = 1410). Operative mortality for all patients was 17.3% (261 deaths). Intraoperative red blood cell (RBC) transfusion portended reduced short-term survival (odds ratio {OR} 2.00, p = 0.025). Massive postoperative transfusion was associated with prolonged ventilation (OR 13.47, p < 0.001), sepsis (OR 4.13, p < 0.001), and new dialysis-dependent renal-failure (OR 2.43, p < 0.001). Females were more likely to require transfusion (OR 3.03, p < 0.001), as were patients who had coronary bypass (OR 1.57, p = 0.009), and those in shock (OR 2.27, p < 0.001). Valve-sparing aortic root replacement (VSARR) was associated with reduced transfusion requirements vs. composite roots. Institutional case volume was not appreciably correlated with transfusion.

CONCLUSIONS

Most patients undergoing root replacement for aortic dissection require blood products. Composite root replacement is associated with a greater likelihood of transfusion than a valve-sparing operation. Transfusion independently foreshadows greater operative mortality.

Preoperative autologous platelet pheresis reduces allogeneic platelet use and improves the postoperative PaO2/FiO2 ratio in complex aortic surgery: a retrospective analysis

OBJECTIVES

An autologous platelet-rich plasma pheresis (aPP) strategy can harvest partial whole blood that is separated into erythrocytes, plasma and platelets, and can reduce blood loss and transfusion during cardiovascular surgery using cardiopulmonary bypass (CPB). However, the blood and organ conservation effects of this technique have not been confirmed in the context of complex aortic surgery.

METHODS

Perioperative records of 147 adult patients who underwent complex aortic surgery were analysed retrospectively.

RESULTS

All patients received regular blood conservation treatment, and 57 patients received aPP. Whether or not the participants were propensity matched, decreased platelet and cryoprecipitate transfusions were found in the aPP group (both P < 0.001), but there were non-significant differences in erythrocyte transfusion, Sequential Organ Failure Assessment scores and other outcomes when compared with the same parameters in the non-aPP group. The aPP group had a higher arterial oxygen partial pressure to inhaled oxygen concentration ratio on postoperative days 1, 2 and 7 than the non-aPP group (P < 0.001, P < 0.001 and P = 0.048, respectively).

CONCLUSIONS

The utilization of aPP was associated with a reduction in allogeneic platelet and cryoprecipitate transfusions as well as minor lung-protective effects during complex aortic surgery using CPB.

Too Cold to Clot? Does Intraoperative Hypothermia Contribute to Bleeding After Aortic Surgery?

Background

We determined the impact of intraoperative hypothermia on postoperative bleeding after thoracic aortic surgery.

Methods

We retrospectively analyzed 98 consecutive patients who underwent aortic surgery with deep hypothermic circulatory arrest between 2010 and 2014. We evaluated lowest temperature, absolute decrease in temperature, and rewarming rate. Univariate and multivariate regression were used to determine relationships between temperature, clinical characteristics, and measures of postoperative bleeding.

Results

The mean age of patients was 60.5 ± 15.1 years, with 64.3% male and 60% Caucasian. The lowest temperatures recorded were 13.5 ± 4.6°C at the bypass circuit. Change in hematocrit was associated with ethnicity, preoperative hematocrit, and rewarming rate. Chest tube output was associated with body mass index, preoperative platelet count, prior cardiac surgery, cardiopulmonary bypass (CPB) duration, intraoperative blood product transfusion, lowest surface temperature, and change in surface temperature. Postoperative packed red blood cell transfusion was associated with ejection fraction, chronic obstructive pulmonary disease (COPD), platelet count, partial thromboplastin time, CPB duration, and lowest blood temperature. Fresh frozen plasma transfusion correlated with COPD, CPB duration, and final blood temperature. Platelet transfusion correlated with body mass index and preoperative platelet count. Unplanned reoperation for bleeding was associated with final temperature and change in temperature.

Conclusion

We found no consistent associations between intraoperative temperature and indicators of bleeding. Intraoperative cooling strategies should be based on optimal end-organ protection rather than fear of postoperative bleeding; rewarming strategies may ameliorate the risk of coagulopathy.

The Effect of Blood Transfusion on Outcomes in Aortic Surgery

The use of blood transfusion in cardiac surgery varies widely. The beneficial effects of blood products are offset by an increase in morbidity and mortality. Despite multiple studies showing an association between blood product exposure and adverse short- and long-term events, it is difficult to determine causality. Nevertheless, the implication is sufficient to warrant the search for alternative strategies to reduce the use of blood products while providing a standard of care that optimizes postoperative outcomes. Aortic surgery, in particular, is associated with an increased risk of bleeding requiring a blood transfusion. There is a paucity of evidence within aortic surgery regarding the deleterious effects of blood products. Here, we review the current evidence regarding patient outcomes after blood transfusion in cardiac surgery, with special emphasis on aortic surgery.

Aortic root surgery with circulatory arrest: Predictors of prolonged postoperative hospital stay

OBJECTIVE

Little is known about the outcomes of aortic root operations that involve inducing hypothermic circulatory arrest for relatively extensive proximal aortic surgery. We attempted to identify predictors of postoperative hospital length of stay (LOS) and factors that affect postoperative recovery.

METHODS

During 2006-2014, 247 of 265 patients (93.2%) with disease extending into the aortic arch survived aortic root operations (206 elective, 41 urgent/emergent) in which hypothermic circulatory arrest with moderate hypothermia was used. Stepwise multivariate regression analysis was performed to identify predictors of LOS (as a continuous variable) and prolonged LOS (defined as LOS >9 days, the median for the cohort). By this definition, 111 patients (45%) had prolonged LOS and 136 (55%) did not.

RESULTS

Preoperative factors that independently predicted longer LOS in the entire cohort included age (P = .0014), redo sternotomy (P = .0047), and intraoperative packed red blood cell (PRBC) transfusion (P = .0007). Redo sternotomy and intraoperative PRBC transfusion also predicted longer LOS in 3 subgroup analyses: one of elective cases, one from which total arch replacement procedures were excluded, and one limited to patients who were discharged home. Age predicted longer LOS in the non-total arch (hemiarch) replacement patients. Ventilator support >48 hours (P < .0001) was associated with longer LOS. Elective aortic valve-sparing root replacement predicted a shorter LOS than valve replacement in multivariate regression analysis (P = .028).

CONCLUSIONS

In patients undergoing aortic root surgery with hypothermic circulatory arrest for disease extending into the aortic arch, reducing intraoperative PRBC transfusion except when absolutely necessary may reduce postoperative LOS and expedite recovery. Performing aortic valve-sparing root replacement, when feasible, may also reduce LOS.

Blood transfusion and coagulation management

Despite impressive progress in surgical technique, aortic surgery is still associated with relatively high morbidity and mortality. One of the most important contributors to this phenomenon is the triad of bleeding, anemia, and transfusion. All three factors are known to influence the outcome of aortic surgery to a great extent. However, over the last few years a multidisciplinary, multimodal concept has been established, which enables the physician to avoid bleeding, anemia, and transfusion as much as possible. The concept of "patient blood management" combines several established measures with the potential to improve perioperative outcome. This chapter describes these measures with regard to aortic surgery and assesses their respective efficacy.

A novel approach to modeling acute normovolemic hemodilution

Acute normovolemic hemodilution (ANH) was introduced as a blood conservation technique to reduce patient exposure to allogenic blood transfusion during surgery. Despite years of research and experience, the best practice procedure, efficacy and safety of ANH remain in question. In this work, a numerical model is developed for the ANH procedure based upon a multi-compartmental, fluid model of the body. The model also analyzes the most commonly used acellular fluids for ANH or for fluid therapy following hemorrhage. The model allows user input of critical ANH parameters, providing the ability to simulate the patient׳s response in real time to many clinical scenarios, using various types of resuscitation fluids. First, the patient׳s response to a representative, clinical ANH protocol and surgery was simulated. Then, the effect of several variables was investigated including: type/amount of resuscitation fluid, number of blood units collected during ANH, and amount of surgical blood loss. Our simulations highlighted the importance of osmotic molecules within the blood in preventing excessive fluid retention and initiating fluid clearance after surgery. The developed model can be utilized as a tool to simulate and optimize a variety of proposed protocol related to the ANH procedure and surgery. It can also be utilized as an educational or training tool to become familiar with the ANH procedure.