Impact of transfusion on stroke after cardiovascular interventions: Meta-analysis of comparative studies

Risk of Transfusion in Isolated Coronary Artery Bypass Graft: Models Developed From The Society of Thoracic Surgeons Database

BACKGROUND

Perioperative blood transfusion is associated with adverse outcomes and higher costs after coronary artery bypass graft (CABG) surgery. We developed risk assessments for patients' probability of perioperative transfusion and the expected transfusion volume to improve clinical management and resource use.

METHODS

Among 1,266,545 consecutive (2008-2016) isolated CABG operations in The Society of Thoracic Surgeons Adult Cardiac Surgery Database, 657,821 (51.9%) received perioperative transfusions of red blood cells (RBC), fresh frozen plasma (FFP), cryoprecipitate, and/or platelets. We developed "full" models to predict perioperative transfusion of any blood product, and of RBC, FFP, or platelets. Using least absolute shrinkage and selection operator model selection, we built a rapid risk score based on 5 variables (age, body surface area, sex, preoperative hematocrit, and use of intra-aortic balloon pump).

RESULTS

C statistics for the full model were 0.785, 0.815, 0.707, and 0.699 for any blood product, RBC, FFP, and platelets, respectively. C statistics for rapid risk assessments were 0.752, 0.785, 0.670, and 0.661 for any blood product, RBC, FFP, and platelets, respectively. The observed vs expected risk plots showed strong calibration for full models and risk assessment tools; absolute differences between observed and expected risks of transfusion were <10.8% in each percentile of expected risk. Risk assessment-predicted probabilities of transfusion were strongly and nonlinearly associated (P < .0001) with total units transfused.

CONCLUSIONS

These robust and well-calibrated risk assessment tools for perioperative transfusion in CABG can inform surgeons regarding patients' risks and the number of RBC, FFP, and platelets units they can expect to need. This can aid in optimizing outcomes and increasing efficient use of blood products.

Prophylactic Left Atrial Appendage Ligation During Coronary Artery Bypass Graft Surgery Allows Safe Avoidance of Anticoagulation Regardless of Postoperative Atrial Fibrillation

Background New-onset postoperative atrial fibrillation (POAF) is the most common arrhythmia following cardiac surgery. POAF increases the risk of thromboembolism and stroke, as well as morbidity and mortality more generally. Despite evidence from the landmark PROTECT-AF and PREVAIL trials, left atrial appendage ligation (LAAL) is not routinely performed for thromboembolism prophylaxis in POAF, and anticoagulation remains the standard of care along with dual antiplatelet therapy. This study evaluated the efficacy of concomitant LAAL in eliminating the need for postoperative anticoagulation, regardless of POAF development, in patients undergoing coronary artery bypass grafting (CABG). Methods Between 2019 and 2021, 130 patients were selected to undergo concomitant LAAL while undergoing CABG surgery. Patients were then monitored for the incidence of new-onset POAF, and anticoagulation was strictly avoided for this indication. Demographic and outcome data were collected, with endpoints including transient ischemic attack (TIA) or stroke, death, and readmission within one year, as well as the length of hospital and intensive care unit (ICU) admissions. Results POAF occurred in 37 patients (28.5%), consistent with previous reports. However, none of the POAF patients experienced TIA or stroke during the one-year follow-up period, compared to 2 (2.15%) in the non-POAF group, a typical rate of postoperative stroke in such a patient population. No significant differences were observed between POAF and non-POAF cohorts in one-year stroke, all-cause mortality, readmission rates, or total hospital stay. Interestingly, the POAF cohort had a significantly longer mean ICU stay (4.24 vs 3.37 days, p = 0.0219), possibly due to the time required for arrhythmia control before discharge. The study population had a high mean CHA2DS2-VASc score (2.81), indicating an increased risk of thromboembolism, and a high mean HAS-BLED score, suggesting an elevated bleeding risk with anticoagulation. Conclusions LAAL appears to be an effective adjunct to CABG for thromboembolism prophylaxis in POAF. Formal anticoagulation was avoided in this study, with no significant differences in adverse events between POAF and non-POAF groups, suggesting that LAAL may be a suitable alternative to anticoagulation, especially in high-risk patients (e.g., those with elevated CHA2DS2-VASc or HAS-BLED scores). The safety and efficacy of this approach should be corroborated by larger randomized studies, such as the ongoing LeAAPS trial. LAAL during CABG may help reduce the risk of bleeding complications associated with anticoagulation while maintaining protection against thromboembolic events in patients who develop POAF.

Association Between Congenital Heart Disease and Stroke: Insights from a National Database

To delineate prevalence of stroke in the pediatric intensive care unit and to determine risk factors for stroke and association of stroke with mortality in patients with congenital heart disease. Retrospective cohort study. Patients admitted to pediatric intensive care units in the USA participating in the Pediatric Health Information System database from 2016 to 2021. Patients were categorized as those who experienced ischemic or hemorrhagic stroke and those with congenital heart disease. We performed univariate and multivariate logistic regressions to determine risk factors associated with stroke and then developed a predictive model for stroke development in patients with congenital heart disease. Of 426,029 admissions analyzed, 4237 (0.9%) patients experienced stroke and 1197 (1.4%) of 80,927 patients with congenital heart disease developed stroke (odds ratio 1.15, 95% confidence interval 1.06-1.24). Patients with congenital heart disease, younger age, extracorporeal membrane oxygenation, mechanical ventilation, and cardiac arrest were most strongly associated with increased risk of stroke. Stroke increased odds of mortality for patients with congenital heart disease (odds ratio 2.49, 95% confidence interval 2.08-2.98). A risk score greater than 0 was associated with a 33.3% risk of stroke for patients with congenital heart disease (negative predictive value of 99%, sensitivity 69%, specificity 63%). Children with congenital heart disease are at increased risk for developing stroke, which is associated with increased mortality. Early identification of the most vulnerable patients may enable providers to implement preventative measures or rapid treatment strategies to prevent neurologic morbidity.

Perioperative Red Blood Cell Transfusion Is Associated With Adverse Cardiovascular Outcomes in Heart Valve Surgery

BACKGROUND

We examined the relationship between blood transfusion and long-term adverse events to evaluate the clinical impact of red blood cell (RBC) transfusion on patients undergoing cardiac valve surgery.

METHODS

From the National Health Insurance Service database, individuals undergoing heart valve surgery were verified, including aortic valve (AV), mitral valve (MV), tricuspid valve (TV), and complex valves (more than 2 valve surgeries). The interested outcomes were incidence of death, ischemic stroke, hemorrhagic stroke, and admission for myocardial infarction during follow-up. Associations between perioperative RBC transfusion and long-term cardiovascular events were analyzed with Cox-proportional hazard model.

RESULTS

Perioperative RBC transfusion (±2 days from the day of surgery) was categorized into 0, 1, 2, and >3 units based on the number of packs transfused. From 2003 to 2019, the data of 58,299 individuals were retrieved (51.6% were male and 58% were aged above 60 years). The median follow-up duration was 5.53 years. Of the total cohort, 86.5% received at least 1 transfusion. In multivariable analysis, adverse cardiovascular event risk proportionally increased with transfusion in a dose-dependent manner. The adjusted hazard ratios and 95% confidence intervals of outcomes after the transfusion of 1, 2, and ≥3 units compared to those with no transfusion were as follows: death, 1.53 (1.41-1.66), 1.97 (1.81-2.14), and 3.03 (2.79-3.29); ischemic stroke, 1.27 (1.16-1.39), 1.31 (1.19-1.44), and 1.51 (1.38-1.66); hemorrhagic stroke, 1.38 (1.16-1.66), 1.71 (1.43-2.05), and 2.31 (1.94-2.76); and myocardial infarction 1.35 (1.13-1.62), 1.60 (1.33-1.91), and 1.99 (1.66-2.38), respectively (all P < .01).

CONCLUSIONS

In the analysis of the national cohort, perioperative RBC transfusion during heart valve surgery was associated with adverse cardiovascular outcomes correlated with the volume of RBC transfusion.

Efficacy and safety of ECG-synchronized pulsatile extracorporeal membrane oxygenation in the clinical setting: The SynCor Trial

INTRODUCTION

Mechanical circulatory support (MCS) devices are increasingly used as a treatment option in resuscitation or in patients with cardiogenic shock (CS). Prophylactic implantation in high-risk percutaneous coronary interventions (HRPCI) is another upcoming indication. The i-cor ECG-synchronized cardiac assist device combines the hemodynamic support of a veno-arterial extracorporeal membrane oxygenation (VA-ECMO) with the ability to generate a pulsatile flow and thus decreasing adverse effects of VA-ECMO on myocardial function. Aim of this study was to obtain data concerning feasibility, safety and outcomes in both indications.

METHODS

A total of 47 patients (34 HRPCI, 13 CS) were included in nine German centers and participated in this study. Demographic and clinical parameters, procedural as well as follow-up data were prospectively recorded and analyzed.

RESULTS

Device implantation and initiation of ECG-synchronized cardiac assist was technical successful in all cases and no failures of the consoles or disposable parts were observed. Furthermore, intended percutaneous coronary interventions and successful weaning from cardiac assist was achieved in 97.1% of HRPCI patients. We observed a 30d-survival of 94.1% in the HRPCI group and 69.2% in the CS group. Main complications in both groups were bleeding events (14.7% HRPCI, 23.1% CS) and critical limb ischemia (2.9% HRPCI, 38.5% CS).

CONCLUSION

The i-cor ECG-synchronized cardiac assist device appears safe and feasible showing clinical outcomes comparable to existing data in the setting of high-risk percutaneous coronary interventions and acute cardiogenic shock. Further prospective trials are warranted to identify optimal patient and interventional characteristics that will benefit most of this novel kind of mechanical circulatory support.

Red blood cell transfusion induces abnormal HIF-1α response to cytokine storm after adult cardiac surgery

Patients undergoing cardiac surgery develop a marked postoperative systemic inflammatory response. Blood transfusion may contribute to disruption of homeostasis in these patients. We sought to evaluate the impact of blood transfusion on serum interleukin-6 (IL-6), hypoxia induced factor-1 alpha (HIF-1α) levels as well as adverse outcomes in patients undergoing adult cardiac surgery. We prospectively enrolled 282 patients undergoing adult cardiac surgery. Serum IL-6 and HIF-1α levels were measured preoperatively and on the first postoperative day. Packed red blood cells were transfused in 26.3% of patients (mean 2.93 ± 3.05 units) by the time of postoperative sampling. Postoperative IL-6 levels increased over 30-fold and were similar in both groups (p = 0.115), whilst HIF-1α levels (0.377 pg/mL vs. 0.784 pg/mL, p = 0.002) decreased significantly in patients who received red blood cell transfusion. Moreover, greater decrease in HIF-1α levels predicted worse in-hospital and 3mo adverse outcome. Red blood cell transfusion was associated with higher risk of major adverse outcomes (stroke, pneumonia, all-cause mortality) during the index hospitalization. Red blood cell transfusion induces blunting of postoperative HIF-1 α response and is associated with higher risk of adverse thrombotic and pulmonary adverse events after cardiac surgery.

Clinical Trial Registration ClinicalTrials.gov Identifier: NCT03444259.

Coronary Artery Bypass Grafting in Patients With High Risk of Bleeding

BACKGROUND

Postoperative bleeding after cardiac surgery is associated with increased morbidity and mortality. We tested the hypothesis that patients with a preoperatively estimated high risk of severe perioperative bleeding may have impaired early outcome after on-pump versus off-pump coronary artery bypass grafting (CABG).

METHOD

Data from 7,352 consecutive patients who underwent isolated CABG from January 2015 to May 2017 were included in the multicentre European Coronary Artery Bypass Grafting registry. The postoperative bleeding risk was estimated using the WILL-BLEED risk score. Of all included patients, 3,548 had an increased risk of severe perioperative bleeding (defined as a WILL-BLEED score ≥4) and were the subjects of this analysis. We compared the early outcomes between patients who underwent on-pump or off-pump CABG using a multivariate mixed model for risk-adjusted analysis.

RESULTS

Off-pump surgery was performed in 721 patients (20.3%). On-pump patients received more packed red blood cell units (on-pump: 1.41 [95% confidence interval {CI}, 0.99-1.86]; off-pump: 0.86 [95% CI, 0.64-1.08]; p<0.001), had a longer stay in the intensive care unit (on-pump: 4.4 [95% CI, 3.6-8.1] days; off-pump: 3.2 [95% CI, 2.0-4.4] days; p=0.049), and a higher rate of postoperative atrial fibrillation (on-pump: 46.5% [95% CI, 34.9-58.1]; off-pump: 31.3% [95% CI, 21.7-40.9]; p=0.025). Furthermore, on-pump patients showed a trend towards a higher rate of postoperative stroke (on-pump: 2.4% [95% CI, 0.9-4.1]; off-pump: 1.1 [95% CI 0.2-2.7]; p=0.094).

CONCLUSION

Our data suggest that in patients with an increased risk of bleeding, the use of cardiopulmonary bypass is associated with higher morbidity. These patients may benefit from off-pump surgery if complete revascularisation can be ensured.

Neurological Complications of Cardiac Procedures

Neurological complications after cardiac surgery and percutaneous cardiac interventions are not uncommon. These include periprocedural stroke, postoperative cognitive dysfunction after cardiac surgery, contrast-induced encephalopathy after percutaneous interventions, and seizures. In this article, we review the incidence, pathophysiology, diagnosis, and management of these complications. Improved understanding of these complications could lead to their prevention, faster detection, and facilitation of diagnostic workup and appropriate treatment.

Plasmin, Immunity, and Surgical Site Infection

SSI are a universal economic burden and increase individual patient morbidity and mortality. While antibiotic prophylaxis is the primary preventative intervention, these agents are not themselves benign and may be less effective in the context of emerging antibiotic resistant organisms. Exploration of novel therapies as an adjunct to antimicrobials is warranted. Plasmin and the plasminogen activating system has a complex role in immune function. The immunothrombotic role of plasmin is densely interwoven with the coagulation system and has a multitude of effects on the immune system constituents, which may not always be beneficial. Tranexamic acid is an antifibrinolytic agent which inhibits the conversion of plasminogen to plasmin. Clinical trials have demonstrated a reduction in surgical site infection in TXA exposed patients, however the mechanism and magnitude of this benefit is incompletely understood. This effect may be through the reduction of local wound haematoma, decreased allogenic blood transfusion or a direct immunomodulatory effect. Large scale randomised clinical trial are currently being undertaken to better explain this association. Importantly, TXA is a safe and widely available pharmacological agent which may have a role in the reduction of SSI.

Stroke After Percutaneous Coronary Intervention in the Era of Transradial Intervention

BACKGROUND

Periprocedural stroke is a rare but life-threatening complication of percutaneous coronary intervention (PCI). Transradial intervention (TRI) is more beneficial than transfemoral intervention for periprocedural bleeding and acute kidney injuries, but its effect on periprocedural stroke has not been fully investigated. Our study aimed to assess risk predictors of periprocedural stroke according to PCI access site.

METHODS AND RESULTS

Between 2008 and 2016, 17 966 patients undergoing PCI were registered in a prospective multicenter database. Periprocedural stroke was defined as loss of neurological function caused by an ischemic or hemorrhagic event with residual symptoms lasting at least 24 hours after onset. Periprocedural stroke was observed in 42 patients (0.3%). Stroke patients were older and had a higher incidence of chronic kidney disease, peripheral artery disease, and acute coronary syndrome but were less likely to undergo TRI. Multivariable logistic regression analysis revealed TRI (odds ratio; 0.33; 95% CI, 0.16-0.71; P=0.004) was significantly associated with a lower occurrence of periprocedural stroke. Finally, propensity score-matching analysis showed that TRI was associated with a reduced risk of periprocedural stroke compared with transfemoral intervention (0.1% versus 0.4%; P=0.014). According to our sensitivity analysis, this finding was robust to the presence of an unmeasured confounder in almost all plausible scenarios.

CONCLUSIONS

TRI was associated with a reduced risk of periprocedural stroke compared with transfemoral intervention. Increased TRI use may reduce overall PCI complications and should be recommended as the optimal access site for both urgent/emergent and elective PCIs.

The effect of red blood cell transfusion on platelet function in critically ill patients

INTRODUCTION

Red blood cell (RBC) transfusion is associated with an increased risk of pro-thrombotic events, but the underlying mechanism is poorly understood. We hypothesized that RBC transfusion modulates platelet activity in critically ill patients with and without sepsis.

METHODS

In a prospective cohort study, 37 critically ill patients receiving a single RBC unit to correct for anemia were sampled prior to and 1 h after transfusion. Platelet exposure of P-selectin, CD63 and binding of PAC-1 as well as formation of platelet-leukocyte complexes were measured by flow cytometry. The ability of plasma from critically ill patients to induce ex vivo platelet aggregation was assessed by flow cytometry after incubation with platelets from a healthy donor.

RESULTS

RBC transfusion neither triggered the expression of platelet activation markers nor the formation of platelet-leukocyte complexes. Plasma from critically ill patients induced more spontaneous platelet aggregation prior to RBC transfusion compared to healthy controls, which was further augmented following RBC transfusion. Also collagen-induced platelet aggregation was already increased prior to RBC transfusion compared to healthy controls, and this response was unaffected by RBC transfusion. In contrast, ristocetin-induced platelet agglutination was decreased when compared to controls, suggesting impaired vWF-dependent platelet agglutination, even in the presence of high vWF levels. Following RBC transfusion, ristocetin-induced platelet agglutination further decreased. There were no differences between septic and non-septic recipients in all assays.

CONCLUSION

Ex vivo platelet aggregation is disturbed in the critically ill. Transfusion of a RBC unit may further increase the spontaneous platelet aggregatory response.

Platelet Counts and Postoperative Stroke After Coronary Artery Bypass Grafting Surgery

BACKGROUND

Declining platelet counts may reveal platelet activation and aggregation in a postoperative prothrombotic state. Therefore, we hypothesized that nadir platelet counts after on-pump coronary artery bypass grafting (CABG) surgery are associated with stroke.

METHODS

We evaluated 6130 adult CABG surgery patients. Postoperative platelet counts were evaluated as continuous and categorical (mild versus moderate to severe) predictors of stroke. Extended Cox proportional hazard regression analysis with a time-varying covariate for daily minimum postoperative platelet count assessed the association of day-to-day variations in postoperative platelet count with time to stroke. Competing risks proportional hazard regression models examined associations between day-to-day variations in postoperative platelet counts with timing of stroke (early: 0-1 days; delayed: ≥2 days).

RESULTS

Median (interquartile range) postoperative nadir platelet counts were 123.0 (98.0-155.0) × 10/L. The incidences of postoperative stroke were 1.09%, 1.50%, and 3.02% for platelet counts >150 × 10/L, 100 to 150 × 10/L, and <100 × 10/L, respectively. The risk for stroke increased by 12% on a given postoperative day for every 30 × 10/L decrease in platelet counts (adjusted hazard ratio [HR], 1.12; 95% confidence interval [CI], 1.01-1.24; P= .0255). On a given day, patients with moderate to severe thrombocytopenia were almost twice as likely to develop stroke (adjusted HR, 1.89; 95% CI, 1.13-3.16; P= .0155) as patients with nadir platelet counts >150 × 10/L. Importantly, such thrombocytopenia, defined as a time-varying covariate, was significantly associated with delayed (≥2 days after surgery; adjusted HR, 2.83; 95% CI, 1.48-5.41; P= .0017) but not early postoperative stroke.

CONCLUSIONS

Our findings suggest an independent association between moderate to severe postoperative thrombocytopenia and postoperative stroke, and timing of stroke after CABG surgery.