Predictors of bleeding or anemia requiring transfusion in complex endovascular aortic repair and its impact on outcomes in health insurance claims

The Importance of Cell Saver Usage in Complex Endovascular Repair of Thoraco-Abdominal Aortic Aneurysms

BACKGROUND

The use of the cell saver is well-established in open aneurysm repair; however, its role in endovascular repair is yet to be determined. The aim of this study was to analyze the effects of cell saver usage in patients undergoing complex endovascular procedures.

MATERIALS AND METHODS

Single-center retrospective cohort study, including consecutive patients undergoing fenestrated and/or branched repair for the treatment of thoracoabdominal and complex abdominal aortic aneurysms (CAAAs) between January 2019 and December 2022. The cell saver was a standard part of the intraoperative setup of these procedures, and its use was readily available. The primary endpoint was the percentage of patients, in which autologous blood collected was transfused (cell saver blood transfusion [CSBT]), alongside the useable amount obtained. Secondary endpoints included mean blood loss, postoperative hemoglobin levels, and 30-day mortality.

RESULTS

A total of 170 patients (77.1% male, mean age 71.2 ± 9.2 years) were included, with a median blood loss of 700 mL (interquartile range [IQR] 400-1,200 mL). A total of 96 patients received some kind of blood transfusion (BT) (56.5%): 35 patients were (20.6%) allogenic BT, 31 patients were (18.2%) CSBT only, and 30 patients were (17.6%) a combination of both. In total, 61 patients (35.9% or 63.5% of all patients requiring BTs) received CSBT, with a median useable blood volume of 282 mL (IQR, 194.5-508 mL). Thirty-day mortality was similar in both groups. Although the CSBT group had lower intraoperative hemoglobin values (9.25 ± 1.55 vs. 10.36 ± 1.88 mg/dL; P < 0.001), both groups presented similar postoperative hemoglobin (Hb) levels.

CONCLUSIONS

Blood loss during complex endovascular repair is not insignificant. In this cohort, over 50% of included patients required some kind of BT, 32.3% of which received exclusively CSBT, while 31.3% had supplementary CSBT alongside allogenic BT. This data showcases its potential role in these repairs, paving the way for its standardization in the intraoperative setup of these complex procedures.

Editor's Choice - Long Term Outcomes After Invasive Treatment of Carotid Artery Stenosis: a Longitudinal Study of German Health Insurance Claims

OBJECTIVE

There is a paucity of observational data including long term outcomes after invasive treatment for carotid artery stenosis.

METHODS

This retrospective study used nationwide insurance claims from the third largest provider in Germany, DAK-Gesundheit. Patients who underwent inpatient carotid endarterectomy (CEA) or carotid artery stenting (CAS) between 1 January 2008 and 31 May 2017 were included. The Elixhauser comorbidity scores from longitudinally linked hospital episodes were used. Kaplan-Meier analysis and the log rank test were used to determine long term stroke free survival. Multivariable regression models were developed to adjust for confounding.

RESULTS

A total of 22 637 individual patients (41.6% female, median age 72.5 years) were included, of whom 15 005 (66.3%) were asymptomatic and 17 955 (79.3%) underwent CEA. After a median of 48 months, 5 504 any stroke or death events were registered. The mortality rate varied between 0.4% (CEA for asymptomatic stenosis) and 2.1% (urgent CAS for acute stroke patients) at 30 days, and between 4.1% and 8.4% at one year, respectively. The rate for any stroke varied between 0.6% (CEA for asymptomatic stenosis) and 2.5% (CAS for symptomatic patients) at 30 days, and between 2.5% and 6.4% at one year, respectively. The combined rate for any stroke and mortality at one year was 6.3% (CEA for asymptomatic stenosis), 8.7% (CAS for asymptomatic stenosis), and 12.5% (urgent CAS for acute stroke patients). After five years, the overall stroke rate was 7.4% after CEA and 9.0% after CAS. In adjusted analyses, both older age and van Walraven comorbidity score were associated with events, while treatment of asymptomatic stenosis was associated with lower event rates.

CONCLUSION

The current study revealed striking differences between previous landmark trials and real world practice. It further suggested excess deaths among invasively treated asymptomatic patients.

Patient Blood Management in Vascular Surgery

Patient blood management (PBM) is an evidence-based, multidisciplinary approach aimed at appropriately allocating blood products to patients requiring transfusion while simultaneously minimizing inappropriate transfusions. The 3 pillars of patient blood management are optimizing erythropoiesis, minimizing blood loss, and optimizing physiological reserve of anemia. Benefits seen from PBM include limiting hospital costs and mitigating harm from numerous risks of transfusion.

How Does Female Sex Affect Complex Endovascular Aortic Repair? A Single Centre Cohort Study

OBJECTIVE

There is growing evidence of a female patient disadvantage in complex endovascular aortic repair using fenestrated and branched endografts (FB-EVAR) primarily related to peri-procedural events including ischaemic and access vessel complications. This study aimed to determine the impact of sex differences on treatment patterns, and in hospital outcomes in a single centre cohort.

METHODS

This was a retrospective cross sectional single centre cohort study of all consecutive FB-EVAR procedures provided to patients with asymptomatic pararenal and thoraco-abdominal aortic aneurysm (TAAA) between 1 January 2010 and 28 February 2021. Adjusted multivariable logistic regression models were developed using backward (Wald) elimination of variables to determine the independent impact of female sex on short term outcomes.

RESULTS

In total, 445 patients (24.3% females, median age 73.0 years, IQR 66, 78) were included. Female patients had a smaller aneurysm diameter, less frequent coronary artery disease (29.6% vs. 44.8%, p = .007) and history of myocardial infarction (2.8% vs. 15.4%, p < .001) when compared with males. Females were more frequently treated for TAAA than males (49.1% vs. 25.2%, p < .001). The median length of post-procedural hospital stay was 10 days in females and 9 in males. In adjusted analyses, female sex was independently associated with higher mortality (odds ratio [OR] 10.135, 95% CI 2.264 - 45.369), post-procedural complications (OR 2.500, 95% CI 1.329 - 4.702), spinal cord ischaemia (OR 4.488, 95% CI 1.610 - 12.509), sepsis (OR 4.940, 95% CI 1.379 - 17.702), and acute respiratory insufficiency (OR 3.283, 95% CI 1.015 - 10.622) after pararenal aortic aneurysm repair during the hospital stay.

CONCLUSION

In this analysis of consecutively treated patients, female sex was associated with increased in hospital mortality, peri-procedural complications, and spinal cord ischaemia after elective complex endovascular repair of pararenal aortic aneurysm, while no differences were revealed in the TAAA subgroup. These results suggest that sex related patient selection and peri-procedural management should be studied in future research.

Extensive Aortic Stent Graft Coverage for Thoracoabdominal Aortic Aneurysm is Associated With Hemorrhagic Complications Induced by Disseminated Intravascular Coagulation

BACKGROUND

Hybrid endovascular repair for thoracoabdominal aortic aneurysm (TAAA) is a less invasive alternative treatment than conventional open repair. However, disseminated intravascular coagulation (DIC) and hemorrhagic complications can occur postoperatively. We investigated risk factors for hemorrhagic complications after hybrid endovascular TAAA repair.

METHODS

Sixty-one patients who underwent elective hybrid endovascular TAAA repair between 2007 and 2020 were included. Laboratory data before and after placing stent graft were collected, and DIC was diagnosed using a scoring system established by the Japanese Association for Acute Medicine. The length of the stent graft used to cover the aorta was defined as the aortic coverage length, which was measured using the first postoperative computed tomography image. Predictors of unexpected hemorrhagic complications were evaluated.

RESULTS

Postoperative thrombocytopenia was observed in 57 (93%) patients, and their platelet count decreased significantly after stent graft placement (14.3 [9.5-18.0] vs. 8.2 [5.4-10.9] × 10⁴/µL, P < 0.001). Fifteen (25%) and 45 patients (74%) were diagnosed with DIC before and after stent graft placement, respectively. Hemorrhagic complications were observed in 21 patients (34%). Multivariate logistic regression analysis revealed that aortic coverage length was an independent risk factor for hemorrhagic complications (odds ratio 1.441/50 mm increase; 95% confidence interval, 1.041-1.994, P = 0.027). The cutoff value for aortic coverage length obtained from the receiver operating characteristic curve (area under the curve = 0.72) was 304.4 mm (sensitivity 0.76, specificity 0.70).

CONCLUSION

Aortic coverage length is a risk factor for hemorrhagic complications. Patients undergoing extensive aortic coverage greater than 304 mm should be closely monitored.

Female Sex and Outcomes after Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm: A Propensity Score Matched Cohort Analysis

OBJECTIVE

Previous studies have showed a potential disadvantage of female patients who underwent abdominal aortic aneurysm (AAA) repair. The current study aims to determine sex-specific perioperative and long-term outcomes using propensity score matched unselected nationwide health insurance claims data.

METHODS

Insurance claims from a large German fund were used, covering around 8% of the insured German population. Patients who underwent endovascular aortic repair (EVAR) for intact AAA from 1 January 2011 to 30 April 2017 were included in the cohort. A 1:2 female to male propensity score matching was applied to adjust for confounding variables. Perioperative and long-term outcomes after 5 years were determined using matching and regression methods.

RESULTS

Among a total of 3736 patients (19.3% females, mean 75 years) undergoing EVAR for intact AAA, we identified 1863 matched patients. Before matching, females were more likely to be previously diagnosed with hypothyroidism, electrolyte disorders, rheumatoid disorders, and depression, while males were more often diabetics. In the matched sample, 23.4% of the females and 25.8% of the males died during a median follow-up of 776 and 792 days, respectively. Perioperatively, females were more likely to exhibit acute limb ischemia (5.3% vs. 3.2%, p = 0.031) and major bleeding (22.0% vs. 15.9%, p = 0.001) before they were discharged to rehabilitation (5.5% vs. 1.5%, p < 0.001) when compared to males. No statistically significant difference in perioperative (odds ratio 1.12, 95% CI 0.54-2.16) or long-term mortality (hazard ratio 0.91, 95% CI 0.76-1.08) was observed between sexes. This was also true regarding aortic reintervention rates after 1 year (2.0% vs. 2.9%) and 5 years (10.9% vs. 8.1%).

CONCLUSION

The current retrospective matched analysis of insurance claims revealed high early access-related morbidity in females when compared to their male counterparts. Short-term or long-term survival and reintervention outcomes were similar between sexes.

Effect of Blood Loss and Transfusion Requirements on Clinical Outcomes of Fenestrated-Branched Endovascular Aortic Repair

OBJECTIVE

The aim of this study was to evaluate the effect of blood loss and transfusion requirements on clinical outcomes of patients treated by fenestrated-branched endovascular aortic repair (F-BEVAR) for pararenal (PRA) and thoracoabdominal aortic aneurysms (TAAAs).

METHODS

We reviewed the clinical data of 370 consecutive patients (277 male, mean age 74 ± 10 years) treated by F-BEVAR between 2007 and 2017. Outcomes were estimated blood loss (EBL), use of intraoperative blood salvage (IOBS), transfusion of packed red blood cells (PRBCs), mortality, and major adverse events (MAEs).

RESULTS

There were 189 patients (51%) treated for PRAs and 181 patients (49%) treated for TAAAs. IOBS was used in 194 patients (52%) and transfusion of PRBCs was needed in 137 (37%). Thirty-day mortality was 2.2% (8/370) and MAEs occurred in 123 patients (33%), including 74 patients (20%) who had EBL > 1L. EBL > 1L and transfusion of PRBCs were significantly higher (P < 0.05) in patients treated in the first half of clinical experience and in those with larger aneurysms, iliofemoral conduits, bilateral open surgical femoral access and Extent I-III TAAAs. Use of DrySeal^® sheaths (WL Gore, Flagstaff AZ) was associated with significantly lower (P < .05) EBL volume and with less transfusion of PRBCs. On multivariate analysis PRBCs > 1L, male gender and the last half of clinical experience were associated with MAEs/mortality.

CONCLUSIONS

F-BEVAR was associated with significantly higher volume of blood loss and transfusion requirements in patients treated in the early experience and in those who had iliofemoral conduits, open femoral surgical exposure or Extent I-III TAAAs.

Quality of care in surgical/interventional vascular medicine: what can routinely collected data from the insurance companies achieve?

The complexity and diversity of surgical/interventional vascular medicine necessitate innovative and pragmatic solutions for the valid measurement of the quality of care in the long term. The secondary utilization of routinely collected data from social insurance institutions has increasingly become the focus of interdisciplinary medicine over the years. Owing to their longitudinal linkage and pan-sector generation, routinely collected data make it possible to answer important questions and can complement quality development projects with primary registry data. Various guidelines exist for their usage, linkage, and reporting. Studies have shown good validity, especially for endpoints with major clinical relevance. The numerous advantages of routinely collected data face several challenges that require thorough plausibility and validity procedures and distinctive methodological expertise. This review presents a discussion of these advantages and challenges and provides recommendations for starting to use this increasingly important source of data.

Machine learning-based prediction of transfusion

Background

The ability to predict transfusions arising during hospital admission might enable economized blood supply management and might furthermore increase patient safety by ensuring a sufficient stock of red blood cells (RBCs) for a specific patient. We therefore investigated the precision of four different machine learning–based prediction algorithms to predict transfusion, massive transfusion, and the number of transfusions in patients admitted to a hospital.

Study Design and Methods

This was a retrospective, observational study in three adult tertiary care hospitals in Western Australia between January 2008 and June 2017. Primary outcome measures for the classification tasks were the area under the curve for the receiver operating characteristics curve, the F₁ score, and the average precision of the four machine learning algorithms used: neural networks (NNs), logistic regression (LR), random forests (RFs), and gradient boosting (GB) trees.

Results

Using our four predictive models, transfusion of at least 1 unit of RBCs could be predicted rather accurately (sensitivity for NN, LR, RF, and GB: 0.898, 0.894, 0.584, and 0.872, respectively; specificity: 0.958, 0.966, 0.964, 0.965). Using the four methods for prediction of massive transfusion was less successful (sensitivity for NN, LR, RF, and GB: 0.780, 0.721, 0.002, and 0.797, respectively; specificity: 0.994, 0.995, 0.993, 0.995). As a consequence, prediction of the total number of packed RBCs transfused was also rather inaccurate.

Conclusion

This study demonstrates that the necessity for intrahospital transfusion can be forecasted reliably, however the amount of RBC units transfused during a hospital stay is more difficult to predict.

The Interplay between Preoperative Anemia and Postoperative Blood Transfusion on Survival following Fenestrated Aortic Aneurysm Repair

BACKGROUND

Anemia is associated with a higher mortality following standard endovascular aortic repair (EVAR). This study evaluates the impact of anemia on fenestrated endovascular aneurysm repair (FEVAR) for complex aneurysm (AAA) repair.

METHODS

All elective FEVARs performed between 2010 and 2018 at a tertiary vascular center were analyzed. Anemia was defined as a preoperative hemoglobin (Hb) of <120 g/L for women and <130 g/L for men (World Health Organization definition). Primary outcome was overall survival by Kaplan-Meier. Secondary outcomes included length of hospital stay (LOS) and myocardial infarction (MI). Cox proportional hazard analyses were conducted.

RESULTS

In total, 132 FEVAR patients were followed up for 3.7 (2.2) years. Thirty-eight patients were anemic [average Hb of 112 (13) g/L]. Groups were comparable for age, AAA diameter, body mass index, and comorbidity. Anemic patients had a lower baseline estimated glomerular filtration rate [64.1 (23.2) vs. 70.9 (18.8) mL/min/1.73 m², P = 0.022] and a longer procedural time [242 (103) vs. 195.4 (88) min, P = 0.009] with no difference in the number of fenestrations (P = 0.696). Kaplan-Meier analysis demonstrated a higher mortality (log-rank P = 0.03) with 40% deceased versus 21% nonanemic (P = 0.04) at the end of follow-up. Anemic patients had more postoperative myocardial infarctions (MIs) (4 vs. 2, P = 0.037) and a longer LOS [9.2 (7.1) vs. 6.3 (6.8) days, P = 0.001]. Increasing Hb increased the likelihood of survival [hazard ratio, HR -0.8 (0.65-0.94), P = 0.038]. Postoperative transfusion was adversely associated with survival [HR 3.65 (1.05-12.8), P = 0.043].

CONCLUSIONS

Anemia appears to be associated with an increased rate of postoperative MI, LOS, frequency of blood transfusion, and mortality rate following FEVAR but this surpassed by postoperative blood transfusion. Optimization of preoperative Hb should be considered as a potential target for improvements in clinical outcomes and hypothetically a consequential reduction in postoperative red blood cell transfusion need.

Incidence, predictors, and outcomes of spinal cord ischemia in elective complex endovascular aortic repair: An analysis of health insurance claims

OBJECTIVE

This study aimed to determine predictors and outcomes associated with spinal cord ischemia (SCI) after elective fenestrated or branched endovascular aneurysm repair (F/BEVAR) of thoracoabdominal aortic aneurysm (TAAA), abdominal aortic aneurysm (AAA), or aortic dissection.

METHODS

Health insurance claims data of Germany's third largest insurance provider, DAK-Gesundheit, were used to investigate SCI in elective F/BEVAR performed between 2008 and 2017. The International Classification of Diseases and German Operation and Procedure Classification System were used. We stratified the results into F/BEVAR with one or two (AAA) vs three or more (TAAA) fenestrations or branches.

RESULTS

A total of 877 patients (18.9% female; 5.8% with SCI) matching the inclusion criteria were identified during the study period. SCI occurred more often after F/BEVAR of TAAA vs AAA (10.7% vs 3.0%; P < .001). SCI was associated with female sex in the AAA group (odds ratio, 3.87; 95% confidence interval [CI], 1.25-11.15; P = .014) and with cardiac arrhythmias in the TAAA group (odds ratio, 2.98; 95% CI, 1.24-7.06; P = .013). Compared with patients without SCI, SCI patients were more likely to suffer from drug use disorders (eg, opioids, cannabinoids, sedatives) in the TAAA group (17.6% vs 2.1%; P < .05). After F/BEVAR of TAAA, the occurrence of SCI was associated with higher 90-day mortality (14.7% vs 1.1%; P < .05), longer postoperative hospital stay (22 vs 9 days; P < .05), and severe adverse events, such as acute respiratory insufficiency (44.1% vs 12.7%), acute renal failure (35.3% vs 11.3%), and pneumonia (29.4% vs 4.9%; all P < .05). In adjusted analyses, SCI was associated with worse long-term survival after F/BEVAR for TAAA (hazard ratio, 2.54; 95% CI, 1.37-4.73; P < .003).

CONCLUSIONS

Female AAA patients and TAAA patients with cardiac arrhythmias are at highest risk for development of SCI after F/BEVAR. The occurrence of this event was strongly associated with higher major complication rates and worse short-term and long-term survival. This emphasizes a need to further illuminate the value of spinal cord protection protocols in F/BEVAR.