Relationship between leukocyte count and patient risk for excessive blood loss after cardiac surgery

Development and validation of a nomogram for blood transfusion during intracranial aneurysm clamping surgery: a retrospective analysis

PURPOSE

Intraoperative blood transfusion is associated with adverse events. We aimed to establish a machine learning model to predict the probability of intraoperative blood transfusion during intracranial aneurysm surgery.

METHODS

Patients, who underwent intracranial aneurysm surgery in our hospital between January 2019 and December 2021 were enrolled. Four machine learning models were benchmarked and the best learning model was used to establish the nomogram, before conducting a discriminative assessment.

RESULTS

A total of 375 patients were included for analysis in this model, among whom 108 received an intraoperative blood transfusion during the intracranial aneurysm surgery. The least absolute shrinkage selection operator identified six preoperative relative factors: hemoglobin, platelet, D-dimer, sex, white blood cell, and aneurysm rupture before surgery. Performance evaluation of the classification error demonstrated the following: K-nearest neighbor, 0.2903; logistic regression, 0.2290; ranger, 0.2518; and extremely gradient boosting model, 0.2632. A nomogram based on a logistic regression algorithm was established using the above six parameters. The AUC values of the nomogram were 0.828 (0.775, 0.881) and 0.796 (0.710, 0.882) in the development and validation groups, respectively.

CONCLUSIONS

Machine learning algorithms present a good performance evaluation of intraoperative blood transfusion. The nomogram established using a logistic regression algorithm showed a good discriminative ability to predict intraoperative blood transfusion during aneurysm surgery.

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study

BACKGROUND

The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran.

METHODS

A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed.

RESULTS

During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 10/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99-1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 10/L. For leukocyte counts < 6.75 × 10/L, the HR (95% CI) was 0.88 (0.69-1.13), and for leukocyte counts ≥ 6.75 × 10/L, the HR (95% CI) was 1.28 (1.09-1.51).

CONCLUSION

This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.

CLINICAL TRIAL REGISTRATION

NCT02414035, https://clinicaltrials.gov.

Hematological Changes in Patients Undergoing Coronary Artery Bypass Surgery: a Prospective Study

Objectives:

Removal of pro inflammatory stimuli after CABG, wound closure and the regenerative ability of the bone marrow will ensure a gradual recovery of hematological parameters. The aim of this study was to assess the hematological changes after CABG.

Materials and Methods:

A prospective cohort study included 164 consecutive patients undergoing on pump CABG surgery between January 2012 and January 2013. Patients with primary hematologic disease, emergent or urgent CABG and off-pump CABG were not included. A time line protocol was employed.

Results:

All patients survived surgery. Average values of erythrocytes, hemoglobin and hematocrit declined, to reach lower values on day 3 after surgery (-33.6 %, -33.1 %, -32.6 % versus preoperative value, p<0.001) and then gradually increased to reach normal values after one month and the preoperative values after three months. The average values of leukocytes and neutrophils increased rapidly to achieve the highest value on day 2, while the average value of lymphocytes decreased quickly to achieve lower value on day 1 after surgery (+74.7 %, +127.1 %, -52.4 % respectively from the preoperative value, p<0.001). The average platelet count decreased to the lowest value on day 2 after surgery (-26.4 % from the preoperative value, p<0.001), after which gradually increased up to +100.8 % of preoperative value on day 14 (p<0.001) and then gradually decreased to reach normal values on day 21 and preoperative values after three months.

Conclusions:

Average values of the three peripheral blood cells parameters undergo important changes after CABG, but not life threatening, and regain normal and preoperative values after 1-3 months after surgery.

Impact of leukocyte count on mortality and bleeding in patients with myocardial infarction undergoing primary percutaneous coronary interventions: analysis from the Harmonizing Outcome with Revascularization and Stent in Acute Myocardial Infarction trial

BACKGROUND

The relationship between white blood cell count (WBCc) and mortality in patients with ST-segment-elevation acute myocardial infarction treated with percutaneous coronary intervention is poorly understood. Furthermore, whether there is a relationship between WBCc and risk of noncardiac mortality and bleeding after percutaneous coronary intervention is unknown.

METHODS AND RESULTS

The baseline WBCc was available in 3193 of 3345 patients (95.5%) who underwent percutaneous coronary intervention in the Harmonizing Outcome With Revascularization and Stent in Acute Myocardial Infarction (HORIZONS-AMI) trial. In a propensity-adjusted multivariable analysis, WBCc was an independent predictor of 1-year cardiac mortality (hazard ratio, 1.15; 95% confidence interval, 1.09 to 1.22), noncardiac mortality (hazard ratio, 1.19; 95% confidence interval, 1.10 to 1.29), and major bleeding (hazard ratio, 1.08; 95% confidence interval, 1.04 to 1.12). After adjustment for baseline creatinine phosphokinase levels and left ventricular ejection fraction, WBCc remained an independent predictor of 1-year all-cause mortality and cardiac mortality. In patients matched for baseline creatinine phosphokinase levels at hospital admission, the median peak creatinine phosphokinase level was significantly higher in patients with high WBCc (>11 000 per 1 mm(3)) compared with low WBCc (1851 U/L [range, 880-3307 U/L] versus 1241 U/L [range, 540 to 2,78], respectively; P<0.0001). In this subgroup of patients, WBCc was an independent correlate of peak creatinine phosphokinase level, and remained an independent predictor of 1-year mortality.

CONCLUSIONS

In patients with ST-segment-elevation acute myocardial infarction undergoing percutaneous coronary intervention, elevated baseline WBCc is an independent predictor of infarct size, as assessed by peak creatinine phosphokinase level, and of 1-year cardiac mortality, noncardiac mortality, and major bleeding.

The influence of the preoperative immune response on blood transfusion requirements in patients undergoing cardiac surgery

OBJECTIVE

The purpose of this study was to evaluate the influence of preoperative type I and II immune responses on blood transfusion requirements.

DESIGN

A prospective and observational trial.

SETTING

A postcardiac surgery unit of a university hospital.

PARTICIPANTS

Seventy-one consecutive patients undergoing elective cardiac surgery.

INTERVENTIONS

Blood samples drawn for laboratory analysis and immunologic study.

MEASUREMENTS AND MAIN RESULTS

Patients were divided into 2 groups according to blood transfusion requirements: < or = 2 units (n = 35) and >2 units of red blood cells (n = 36). The preoperative immune response was assessed by flow cytometry, measuring the proportion of CD4+ T helper cells producing cytokines, including Th1 response (interferon-gamma and tumor necrosis factor-alpha [TNF-alpha]) and Th2 response (interleukin 4 and 10). Two logistic regression analyses (including and not including immunologic variables) were used to select and weight perioperative variables associated with an increased risk of transfusion. Three variables were found to be independent predictors of transfusion requirements when immunologic variables were not included: preoperative platelet count, preoperative hemoglobin, and hypertension. When all the variables were included, preoperative hemoglobin, cardiopulmonary bypass time, and the preoperative proportion of CD4+ T cells producing TNF-alpha were associated with an increased risk of transfusion (Hosmer-Lemeshow, 0.33; c-index, 0.93), but preoperative platelet count and hypertension were not.

CONCLUSIONS

A low preoperative Th1 immune response, as assessed by the proportion of CD4+ T-helper-producing TNF-alpha, was associated with a higher blood transfusion rate.

Effects of a leukocyte depleting arterial line filter on perioperative morbidity in patients undergoing cardiac surgery: a controlled randomized trial

BACKGROUND

Activated leukocytes may increase morbidity in cardiac surgery. The objective of this study is to investigate the influence on morbidity of leukocyte-depleting blood filters placed into the arterial line of cardiopulmonary bypass circuits.

METHODS

Simple, blind, prospective, randomized and controlled clinical trial carried out in a cardiac surgery ICU at a university center. We included 159 consecutive low-risk patients (ie, Parsonnet score < 10) undergoing cardiac surgery who were initially stratified in three risk levels according to the Parsonnet score at admission into the hospital (ie, low, < 4; middle, 4 to 7; and high, 8 to 10). Once stratified, all patients were randomized to undergo cardiopulmonary bypass either with a conventional blood filter or with a leukocyte filter (randomization ratio, 2:1). The outcome variable was morbidity. Patients were considered to have a high morbidity if any of the following clinical situations were present (ie, pulmonary dysfunction, cardiac dysfunction, perioperative infections, postoperative hyperthermia, and hyperdynamic states).

RESULTS

The leukocyte filter was used in 52 patients and the conventional filter in 107 patients. The morbidity rate was similar in both groups, but patients with leukocyte filter had a lower incidence of perioperative infections, fever, and hyperdynamic states as compared with patients with the conventional filter.

CONCLUSIONS

Leukocyte filtration in patients undergoing cardiac surgery with extracorporeal perfusion showed no measurable effects on postoperative morbidity. However, although not statistically significant, a decrease was observed in the rates of perioperative infection, fever, and hyperdynamic states.

Trauma Associated Severe Hemorrhage (TASH)-Score: probability of mass transfusion as surrogate for life threatening hemorrhage after multiple trauma

BACKGROUND

To develop a simple scoring system that allows an early and reliable estimation for the probability of mass transfusion (MT) as a surrogate for life threatening hemorrhage following multiple trauma.

METHODS

Potential clinical and laboratory variables documented in the Trauma Registry of the German Trauma Society (DGU) (1993-2003; n=17,200) were subjected to univariate and multivariate logistic regression analysis to predict the probability for MT.

RESULTS

Clinical and laboratory variables available from data sets were screened for their association with mass transfusion. MT was defined by transfusion requirement of >or=10 units of packed red blood cells from emergency room (ER) to intensive care unit admission. Seven independent variables were identified to be significantly correlated with an increased probability for MT: systolic blood pressure (<100 mm Hg=4 pts, <120 mm Hg=1 pt), hemoglobin (<7 g/dL=8 pts, <9 g/dL=6 pts, <10 g/dL=4 pts, <11 g/dL=3 pts, and <12 g/dL=2 pts), intra-abdominal fluid (3 pts), complex long bone and/or pelvic fractures (AIS 3/4=3 pts and AIS 5=6 pts), heart rate (>120=2 pts), base excess (<-10 mmol/L=4 pts, <-6 mmol/L=3 pts, and <-2 mmol/L=1 pt), and gender (male=1 pt). These variables were incorporated into a risk score, the Trauma Associated Severe Hemorrhage Score (TASH-Score, 0-28 points). Performance of the score was tested with respect to discrimination, precision, and calibration. Increasing TASH-Score points were associated with an increasing probability for MT.

CONCLUSION

The TASH-Score is an easy-to-use scoring system that reliably predicts the probability for MT after multiple trauma. Taken as a surrogate for life threatening bleeding calculation may focus attention on relevant variables indicative for risk and impact strategies to stop bleeding and stabilize coagulation in acute trauma care.