Platelet Counts and Postoperative Stroke After Coronary Artery Bypass Grafting Surgery

Coronary artery bypass grafting (CABG) induces pro-inflammatory and immunomodulatory phenotype of platelets in the absence of a pro-aggregatory state

BACKGROUND

Coronary artery bypass grafting (CABG) is considered the choice treatment for patients suffering from coronary artery disease (CAD). In the inflammatory milieu of cardiopulmonary bypass (CPB), systemic inflammatory response syndrome (SIRS) can induce a platelet pro-inflammatory state which could exacerbate post-CABG inflammatory status while affecting hemostatic function in patients. Therefore, focusing on platelets, the study presented here attempted to evaluate the pro-inflammatory and immunomodulatory profile of platelets as well as pro-aggregatory status during CABG.

METHODS

Platelets from patients undergoing CABG were subjected to flowcytometry analysis to evaluate P-selectin and CD40L expressions and PAC-1 binding in five intervals of 24 h before surgery, immediately, 2 h, 24 h, and one week after surgery. Moreover, intra-platelet TGF-β1 was also examined with western blotting.

RESULTS

Data showed increases of P-selectin and CD40L expressions in patients, with the meaningful loss of platelet contents of TGF-β1 after CABG (p < 0.001), where the changes tended to recover by day 7 of surgery while remaining above baseline (p < 0.001). Meanwhile, no significant change in PAC-1 binding capacity was shown.

CONCLUSION

The study presented here suggests that although the release of pro-inflammatory substances from platelets during CABG supports the post-operative inflammatory state, platelets are not pro-aggregatory enough to enhance thrombotic events after surgery. Whilst these observations could be due to successful medical interventions to optimize hemostasis during and after surgery, post-CABG reversal of anticoagulant by protamine is considered as another factor that may also have contributed to preventing pro-aggregatory but not pro-inflammatory and immunomodulatory functions of platelets.

Risk factors and prediction model for thrombocytopenia following coronary artery bypass graft surgery in elderly Chinese population

Background

Thrombocytopenia, a common complication of coronary artery bypass graft (CABG) surgery, is particularly prevalent among elderly individuals. This study developed a risk prediction model utilizing preoperative and intraoperative variables to identify high-risk elderly patients prone to developing thrombocytopenia.

Methods

The patients were retrospectively recruited from Beijing Anzhen Hospital between February 2019 and December 2020. Postoperative thrombocytopenia was defined as a postoperative platelet (PLT) count <100×109/L as measured within 7 days after surgery. The entire population was randomly split into derivation and validation sets in a 7:3 ratio. The derivation set underwent variable screen by the least absolute shrinkage and selection operator (LASSO) regression method. To evaluate the predictive ability of the model for thrombocytopenia, decision curve analysis (DCA) and receiver operating characteristic (ROC) curves were generated in the derivation and validation sets.

Results

A total of 1,773 patients were recruited in this study, with random assignment to either the derivation set (1,242 cases) or the validation set (531 cases). LASSO regression was utilized the risk factors associated with thrombocytopenia, resulting in selection of preoperative baseline variables: body mass index (BMI), estimated glomerular filtration rate (eGFR), B-type natriuretic peptide (BNP), preoperative PLT, and use of beta-blocker, and intraoperative variables: red blood cell (RBC) transfusion, plasma transfusion, use of intra-aortic balloon pump (IABP) and cardiopulmonary bypass (CPB), reoperation for bleeding, washed RBC transfusion volume, and use of epinephrine. The logistic regression was employed to establish the risk prediction. The area under the ROC curve (AUC) for the derivation set was 0.900 [95% confidence interval (CI): 0.880-0.920], while for the validation cohort, it was 0.897 (95% CI: 0.866-0.928).

Conclusions

The model incorporating significant preoperative and intraoperative variables exhibited good predictive performance for thrombocytopenia in elderly patients undergoing CABG surgery.

Association between postoperative nadir platelet count and postoperative cardiovascular complications following septal myectomy in patients with hypertrophic cardiomyopathy: a retrospective cohort study

BACKGROUND

Platelet count is associated with cardiovascular risk and mortality in several cardiovascular diseases, but the association of the nadir platelet counts post-septal myectomy with the cardiovascular complication risk in hypertrophic obstructive cardiomyopathy patients remains unclear.

METHODS

This retrospective cohort study reviewed all adult patients who underwent septal myectomy at a single tertiary referral center over a 5-year period. Postoperative nadir platelet count was defined as the lowest platelet count in the first 4 postoperative days or until hospital discharge. The composite outcome included cardiovascular death, myocardial infarction, heart failure, malignant arrhythmia, cardiac tamponade, and major bleeding events within 30 days postoperatively. Univariable and multivariable logistic regression and restricted cubic spline models were used to assess the association between postoperative nadir platelet count and the 30-day postoperative cardiovascular complication risk.

RESULTS

Among the 113 enrolled patients, 23 (20.4%) developed cardiovascular events within 30 days postoperatively. The incidence of postoperative cardiovascular complications was significantly higher in patients with a nadir platelet count ≤ 99 × 109/L than in those with a nadir platelet count > 99 × 109/L (33.3% vs. 7.1%, crude risk ratio: 4.67, 95% confidence interval: 1.69-12.85, P < 0.001). Multivariable logistic regression revealed that postoperative nadir platelet count was negatively associated with 30-day postoperative cardiovascular complications (adjusted odds ratio: 0.97; 95% confidence interval: 0.95-0.99; P = 0.005) and the association was linear (Pnonlinearity = 0.058) after full adjustment. The association between nadir platelet count and cardiovascular complications within 30 days post-surgery was consistent in all predefined subgroups (Pinteraction > 0.05).

CONCLUSION

The postoperative nadir platelet count was significantly associated with the 30-day post-myectomy risk of cardiovascular complications in hypertrophic obstructive cardiomyopathy patients.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov (NCT04275544).

Processed Electroencephalographic Use During Anesthesia and Outcomes: Analysis of The Society of Thoracic Surgeons Adult Cardiac Surgery Database

BACKGROUND

This study assessed associations between processed electroencephalographic (pEEG) use during anesthesia, surgery- and anesthesia-related risk factors, and neurologic outcomes and mortality after cardiac surgery.

METHODS

Drawing from The Society of Thoracic Surgeons Adult Cardiac Surgery Database and its Adult Cardiac Anesthesiology Section, we identified 42 932 records for elective, urgent, and emergency cardiac surgical procedures between July 1, 2017 and December 31, 2019. Using propensity score-weighted regression analysis, we analyzed the associations between pEEG use during anesthesia on the primary outcome, postoperative delirium (POD), and secondary outcomes of stroke, encephalopathy, coma, and operative mortality.

RESULTS

The rate of pEEG use during anesthesia use was 32.8% (n = 14 086), and its use was not associated with decreased odds for POD (odds ratio [OR], 0.88; 95% CI, 0.78-1.02) or encephalopathy (OR, 0.85; 95% CI, 0.70-1.03). Intraoperative pEEG monitoring use was also not associated with increased odds for stroke (OR, 1.17; 95% CI, 0.97-1.42) or coma (OR, 1.44; 95% CI, 0.82-2.52). In contrast, pEEG use during anesthesia was associated with higher odds for operative mortality (OR, 1.23; 95% CI, 1.05-1.44). This association remained significant after adjusting for POD (OR, 1.21; 95% CI, 1.03-1.41), stroke (OR, 1.21; 95% CI, 1.04-1.42), and encephalopathy (OR, 1.28; 95% CI, 1.07-1.52).

CONCLUSIONS

This large retrospective database study found no association between pEEG use during cardiac surgery and postoperative neurologic outcomes such as POD, stroke, encephalopathy, or coma. However, patients who underwent pEEG monitoring during anesthesia experienced higher mortality, even after adjustment for neurologic outcomes.

Risk Factors of Thrombocytopenia After Cardiac Surgery with Cardiopulmonary Bypass

INTRODUCTION

Postoperative thrombocytopenia is common in cardiac surgery with cardiopulmonary bypass, and its risk factors are unclear.

METHODS

This retrospective study enrolled 3,175 adult patients undergoing valve surgeries with cardiopulmonary bypass from January 1, 2017 to December 30, 2018 in our institute. Postoperative thrombocytopenia was defined as the first postoperative platelet count below the 10th quantile in all the enrolled patients. Outcomes between patients with and without postoperative thrombocytopenia were compared. The primary outcome was in-hospital mortality. Risk factors of postoperative thrombocytopenia were assessed by logistic regression analysis.

RESULTS

The 10th quantile of all enrolled patients (75×109/L) was defined as the threshold for postoperative thrombocytopenia. In-hospital mortality was comparable between thrombocytopenia and non-thrombocytopenia groups (0.9% vs. 0.6%, P=0.434). Patients in the thrombocytopenia group had higher rate of postoperative blood transfusion (5.9% vs. 3.2%, P=0.014), more chest drainage volume (735 [550-1080] vs. 560 [430-730] ml, P<0.001), and higher incidence of acute kidney injury (12.3% vs. 4.2%, P<0.001). Age > 60 years (odds ratio [OR] 2.25, 95% confidence interval [CI] 1.345-3.765, P=0.002], preoperative thrombocytopenia (OR 18.671, 95% CI 13.649-25.542, P<0.001), and cardiopulmonary bypass time (OR 1.088, 95% CI 1.059-1.117, P<0.001) were positively independently associated with postoperative thrombocytopenia. Body surface area (BSA) (OR 0.247, 95% CI 0.114-0.538, P<0.001) and isolated mitral valve surgery (OR 0.475, 95% CI 0.294-0.77) were negatively independently associated with postoperative thrombocytopenia.

CONCLUSION

Positive predictors for thrombocytopenia after valve surgery included age > 60 years, small BSA, preoperative thrombocytopenia, and cardiopulmonary bypass time. BSA and isolated mitral valve surgery were negative predictors.

Platelet Decreases following Continuous Renal Replacement Therapy Initiation as a Novel Risk Factor for Renal Nonrecovery

BACKGROUND

Continuous renal replacement therapy (CRRT) is a form of dialysis used in critically ill patients, and has recently been associated with renal nonrecovery. Decreases in platelets following CRRT initiation are common and are associated with mortality, but associations with renal recovery are unclear. Our objective was to determine if platelet nadir or the degree of platelet decrease following CRRT initiation was associated with renal nonrecovery.

METHODS

This is a secondary analysis of the Randomized Evaluation of Normal versus Augmented Level (RENAL) trial. Primary predictors were platelet nadir discretized by median value and percent platelet decrease following CRRT initiation, with cut points evaluated by decile from 30 to 60%. The 2 primary outcomes were time to RRT-independence and RRT-free days. Secondary outcomes were 28-day mortality, 90-day mortality, intensive care unit (ICU)-free, and hospital-free days.

RESULTS

Time to RRT independence censored for death was achieved less frequently in patients with low platelet nadir (hazard ratio [HR] 0.77, confidence interval [CI] 0.66-0.91) and in those with >50% platelet decrease (HR 0.84, CI 0.72-0.97). RRT-free days were lower in both low platelet nadir (odds ratio [OR] 0.94, CI 0.90-0.97) and >50% platelet decrease (OR 0.91, CI 0.88-0.95). These groups also had higher rates of 28- and 90-day mortality and fewer ICU-free and hospital-free days. Thrombocytopenia at CRRT initiation was also associated with renal nonrecovery, although the clinical effect was small.

CONCLUSIONS

Platelet nadir <100 × 103/µL and platelet decrease by >50% following CRRT initiation were both associated with lower rates of renal recovery. Further research is needed to evaluate mechanisms-linking platelet changes and renal nonrecovery in CRRT.

Mean platelet volume-to-platelet count ratio after elective cardiac surgical procedures is superior in reflecting platelets metabolic hyperactivity compared to other routine morphological platelet indices: A preliminary report

BACKGROUND

Excessive metabolic excitation of platelets after cardiac procedures may be related to some adverse events but assessment of their metabolic activity is not routine. The purpose of this study was to evaluate which of the basic platelet morphological parameters best reflects their metabolic status.

METHODS

The blood samples of 22cardiac surgical patients (mean age of 62.3 ± 10.3 years) were taken before surgery (BS), and 1, 24 and 48 hours after the operation. Correlations between morphological platelet parameters (platelet count [PLT], mean platelet volume [MPV], platelet distribution width [PDW] and MPV/PLT) and their metabolic activity (total concentration of malondialdehyde [MDA] and MDA/PLT) were estimated.

RESULTS

Significant decline in PLT after operation (from 223 ± 44 × 10¹²/L to 166 ± 57 × 10¹²/L) was accompanied by marked increase in MPV (from 8.4 ± 0.9 fL to 9.1 ± 1.2 fL) and no change of PDW. Consequently, MPV/PLT index increased significantly after procedures from (median with IQR) 0.038 (0.030-0.043) to 0.053 (0.043-0.078). Simultaneously, a significant increase in total platelet MDA content and MDA/PLT was noted reaching peak levels soon after operation. The strongest correlation was observed between MPV/PLT and MDA/PLT (r = 0.56; p < 0.001), although the others were also found to be significant (MDA/PLT vs. MPV; r = 0.35; MDA/PLT vs. PDW; r = 0.34).

CONCLUSIONS

Among basic morphological parameters and indices, the MPV-to-PLT ratio reflects the best metabolic status of platelets in cardiac surgical patients.

Association Between Postoperative Thrombocytopenia and Outcomes After Coronary Artery Bypass Grafting Surgery

Objectives: The effect of postoperative thrombocytopenia on adverse events among coronary artery bypass graft (CABG) patients remains unclear. This study aims to investigate the association between postoperative thrombocytopenia and perioperative outcomes of CABG. Methods: This is a retrospective study with MIMIC-III (Medical Information Mart for Intensive Care III) database. Adult patients who underwent CABG were included to analyze the impact of thrombocytopenia in patients' outcomes. Postoperative thrombocytopenia was defined as a platelet count <100 × 10⁹/L on the first day after CABG surgery. A multivariable logistic regression analysis was utilized to adjust the effect of thrombocytopenia on outcomes for baseline and covariates, and to determine the association with outcomes. Results: A total of 4,915 patients were included, and postoperative thrombocytopenia occurred in 696 (14.2%) patients. Postoperative thrombocytopenia was not associated with increased 28-day mortality (OR 0.75; 95% CI 0.33-1.72; P = 0.496) or in-hospital mortality (OR 0.75; 95% CI 0.34-1.63; P = 0.463) after adjusting for confounders. Regarding the secondary outcomes, it was associated with a higher risk of a prolonged stay in the intensive care unit (OR 1.53; 95% CI 1.18-1.97; P = 0.001), prolonged hospital stays (OR 1.58; 95% CI 1.21-2.06; P = 0.001), prolonged mechanical ventilation time (OR 1.67; 95% CI 1.14-2.44; P = 0.009), and a trend toward increased occurrence of massive bleeding (OR 1.41; 95% CI 1.00-2.01; P = 0.054). There was no significant association between an increased risk of prolonged vasopressor use and the continuous renal replacement therapy rate. Conclusions: Postoperative thrombocytopenia was associated with prolonged ICU and hospital stays but not with increased perioperative mortality among CABG patients.

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.

Research on clinical characteristics and prognostic analysis of heparin-induced thrombocytopenia after surgery for acute type a aortic dissection

Purpose

The present study aimed to explore the clinical characteristics of heparin-induced thrombocytopenia (HIT) after surgery for acute type A aortic dissection and perform a relevant prognostic analysis.

Methods

After continuous observation and analysis of 204 patients who underwent acute type A aortic dissection, we found that blood platelets decreased significantly after surgery and that these patients can be suspected to suffer HIT based on relevant 4Ts scores. For these suspected HIT patients, a latex particle-enhanced immunoturbidimetric assay was conducted to detect heparin-induced antibodies. Perioperative clinical data of patients in HIT and non-HIT groups were recorded as were blood platelet counts, HIT antibody test results, 4Ts scores, thromboembolic complications, clinical prognosis and outcomes.

Results

In the present study, 38 suspected HIT patients, 16 HIT patients and 188 non-HIT patients were selected in the clinical setting. Among them, HIT patients were found to have prolonged cardiopulmonary bypass time (223 min on average vs. 164 min) and delayed aortic cross-clamp time (128 min on average vs. 107 min), and these differences between HIT patients and non-HIT patients were significant (P < 0.05). Additionally, the HIT group required longer operation time and higher dose of heparin, but showing no statistical differences (P > 0.05). The transfusions of blood platelets in the HIT group and non-HIT group were 18.7 ± 5.0u and 15.6 ± 7.34 u, respectively. In the HIT group, the mechanic ventilation time and the length of ICU stay were longer comparing the non-HIT group(P < 0.05), though no significant differences in total length of stay or In-hospital mortality were observed (P > 0.05). The incidence of continuous renal replacement therapy in HIT group was higher than the non-HIT group (P < 0.05). Additionally,there were no significant differences in 24-h postoperative drainage or reoperation for bleeding in both group(P > 0.05). However, the HIT antibody titer in the HIT group was significantly higher than that in the Suspected HIT group (2.7 ± 0.8 U/mL vs. 0.3 ± 0.2 U/mL) (P < 0.05). Among patients diagnosed with HIT, the incidence of thromboembolism reached 31.5%.For example, two HIT patients newly developed thromboembolism in both lower extremities,and three patients experienced cerebral infarction.

Conclusions

After surgery for acute type A aortic dissection, HIT patients developed postoperative complications, the duration of ventilatory support and length of ICU stay were extended, and the incidence of thromboembolism increased. HIT antibody detection and risk classification should be implemented for high-risk patients showing early clinical characteristics.

Association of platelet count and mean platelet volume (MPV) index with types of stroke

Background:

Stroke is known to be the third most prominent cause of death in the developing countries and the most common debilitating neurologic disease. This study aimed to investigate the association of platelet count (PC) and mean platelet volume (MPV) index with various stroke types.

Methods:

This cross-sectional study was carried out on patients over the age of 18 years who presented with signs and symptoms of the first acute stroke. Exclusion criteria were underlying chronic liver or renal disease and the time more than 6 hours from symptom initiation, hematological and infectious disorders in patients. After recording of demographic data, a complete blood cell count (CBC) test was performed.

Results:

From 150 patients, who enrolled in the study, 54.7% of patients were males. The initial brain CT scan was normal in 13 (8.7%) patients and showed evidence of brain infarction and intracranial hemorrhage in 84 (56%) and 53 (35.3%) patients respectively. Patients with intracranial hemorrhage had significantly higher mean of MPV index than the patients with normal brain-CT scan and patients with evidence of brain infarction (p<0.001).

Conclusion:

The MVP index can be a predictor of the type of hemorrhagic or ischemic finding in emergency CT scan in stroke patients. This relationship may help to better understand the physiopathologic role of platelets in the development of stroke (hemorrhagic or ischemic), but will not replace cerebral computed tomography to diagnose the type of stroke, or it may not initiate treatment for hemorrhagic stroke.

Association between platelet counts and morbidity and mortality after endovascular repair for type B aortic dissection

This study aimed to assess the association of postoperative platelet counts with early and late outcomes after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). We retrospectively evaluated 892 patients with TBAD who underwent TEVAR from a prospectively maintained database. Postoperative nadir platelet counts were evaluated as a continuous variable, and a categorical variable (thrombocytopenia), which was defined as platelet count≤ the lowest 10% percentile (108 × 10⁹/l). Multivariable logistic regression analyses were conducted to assess the impact of postoperative thrombocytopenia on early outcomes, and multivariable cox regression analyses on long-term mortality. Patients with postoperative thrombocytopenia experienced significantly higher rates of postoperative mortality, prolonged intensive care unit stay, death, stroke, limb ischemia, mesenteric ischemia, acute kidney injury (AKI), and puncture-related hematoma (P< .05 for each), but similar rates of immediate type I endoleak and spinal cord ischemia. Multivariable logistic analyses showed that postoperative thrombocytopenia was independently associated with postoperative stroke, limb ischemia, and AKI. Similar results were observed when postoperative nadir platelet count was modeled as a continuous predictor (P< .05 for each). By multivariable Cox analyses, postoperative thrombocytopenia was an independent predictor for long-term all-cause mortality (hazard ratio 2.72, 95% CI, 1.72-4.29, P< .001). For every 30 × 10⁹/L decrease in postoperative platelet count, the risk of long-term all-cause mortality increased by 15% (HR 1.15; 95% CI 1.07-1.25; P< .001). Therefore, postoperative thrombocytopenia might be a useful tool for risk stratification after TEVAR.

Impact of Thrombocytopenia on Postoperative Bleeding Incidence in Patients Receiving Aspirin Following Coronary Artery Bypass Grafting

BACKGROUND

Early postoperative aspirin following coronary artery bypass graft (CABG) surgery has been shown to maintain bypass graft patency, reduce mortality, and prevent adverse cardiovascular events. Despite this known benefit, aspirin may be delayed due to thrombocytopenia and perceived higher bleeding risk. The purpose of this study was to assess the impact of postoperative platelet count on bleeding in patients receiving aspirin after CABG.

METHODS

A retrospective analysis included all patients who underwent CABG surgery at our institution from April 2014 to June 2018 and received aspirin within 24 hours. The primary outcome was International Society on Thrombosis and Hemostasis (ISTH) major bleeding within 7 days (or up to discharge) following CABG surgery compared between patients with and without postoperative thrombocytopenia.

RESULTS

This study included 280 patients. Major bleeding occurred in 24.6% of the population, with no difference when stratified by the presence or absence of postoperative thrombocytopenia (27.3% versus 23.8%, p = 0.571). There was no significant difference in hemoglobin fall (13.6% versus 14%, p = 0.948), transfusion requirement (6.1% versus 4.2%, p = 0.531), or critical site bleeding (12.1% versus 7.9%, p = 0.298).

CONCLUSION

In this single-center analysis of patients who received aspirin within 24 hours of CABG, postoperative thrombocytopenia was not associated with an increase in bleeding.

Perioperative Precision Medicine: Where Are We in 2020?

PURPOSE OF REVIEW

The present review examines how targeted approaches to care, based on individual variability in patient characteristics, could be applied in the perioperative setting. Such an approach would enhance individualized risk assessment and allow for targeted preventive and therapeutic decision-making in patients at increased risk for adverse perioperative events.

RECENT FINDINGS

Prior and current studies highlight valuable lessons on how future investigations attempting to link specific patient-related characteristics or treatment modalities with outcomes and adverse drug responses might be designed in the perioperative setting.

SUMMARY

Our review highlights the past, present, and future directions of perioperative precision medicine. Current evidence provides important lessons on how a specific patient and disease tailored approach can help perioperative physicians in delivering the most appropriate and safest perioperative care.

Postoperative complications associated with coronary artery bypass graft surgery and their therapeutic interventions

Coronary artery disease is one of the commonest surgery demanding cardiovascular diseases. Coronary artery bypass graft surgery is practiced all over the world for the treatment of coronary artery disease. Systemic trauma during the surgery is associated with a wide range of complications, some of which are fatal. Preoperative risk factors such as age, previous illness and obesity are common predictors of these adverse events. Advances in therapeutic medicine have allowed timely treatment of these adverse events and co-morbidities. This review summarizes some of the most occurring complications associated with coronary artery bypass graft and corresponding treatment options.

Synchronous versus staged carotid artery stenting and coronary artery bypass graft for patients with concomitant severe coronary and carotid artery stenosis: A systematic review and meta-analysis

BACKGROUND

Coronary artery disease requiring coronary artery bypass graft (CABG) frequently coexists with critical carotid stenosis. The most optimized strategy for treating concomitant carotid and coronary artery disease remains debatable.

OBJECTIVE

The aim of this meta-analysis was to compare synchronous CAS and CABG versus staged CAS and CABG for patients with concomitant coronary artery disease and carotid artery stenosis in terms of peri-operative (30-day) and long-term clinical outcomes.

METHODS

This study was performed according to the PRISMA guidelines. Eligible studies were identified through a search of PubMed, Scopus and Cochrane database until December 2019. A meta-analysis was conducted with the use of a random effects model. The I-square statistic was used to assess heterogeneity.

RESULTS

Four studies comprising 357 patients were included in this meta-analysis. Patients who were treated with the synchronous approach had a statistically significant higher risk for peri-operative stoke (OR: 3.71; 95% CI: 1.00-13.69; I² = 0%) compared tο the staged group. Peri-operative mortality (OR: 4.50; 95% CI: 0.88-23.01; I² = 0%), myocardial infarction (MI) (OR: 1.54; 95% CI: 0.18- 13.09; I² = 0%), postoperative bleeding (OR: 0.27;95% CI: 0.02-3.12; I² = 0%), transient ischemic attacks (TIA) (OR: 0.60; 95% CI: 0.04- 9.20; I² = 0.0%), acute kidney injury (AKI) (OR: 0.34; 95% CI: 0.03-4.03; I² = 0.0%) and atrial fibrillation rates (OR:0.27; 95% CI: 0.02-3.12; I² = 0.0%) were similar between the two groups. Synchronous CAS-CABG and staged CAS followed by CABG were associated with similar rates of late mortality (OR: 3.75; 95% CI: 0.50-27.94; I² = 0.0%), MI (OR: 0.33; 95% CI: 0.01-12.03; I² = 0.0%) and stroke (OR:3.58; 95% CI:0.84-15.20; I² = 0.0%) after a mean follow-up of 47 months.

CONCLUSION

The simultaneous approach was associated with an increased risk of 30-day stroke compared to staged CAS and CABG. However, no statistically significant difference was found in long-term results of mortality, MI and stroke between the two approaches. Future studies are warranted to validate our results.

Expert consensus on the diagnosis and treatment of thrombocytopenia in adult critical care patients in China

Thrombocytopenia is a common complication of critical care patients. The rates of bleeding events and mortality are also significantly increased in critical care patients with thrombocytopenia. Therefore, the Critical Care Medicine Committee of Chinese People's Liberation Army (PLA) worked with Chinese Society of Laboratory Medicine, Chinese Medical Association to develop this consensus to provide guidance for clinical practice. The consensus includes five sections and 27 items: the definition of thrombocytopenia, etiology and pathophysiology, diagnosis and differential diagnosis, treatment and prevention.

Platelets trigger perivascular mast cell degranulation to cause inflammatory responses and tissue injury

Platelet responses have been associated with end-organ injury and mortality following complex insults such as cardiac surgery, but how platelets contribute to these pathologies remains unclear. Our studies originated from the observation of microvascular platelet retention in a rat cardiac surgery model. Ensuing work supported the proximity of platelet aggregates with perivascular mast cells (MCs) and demonstrated that platelet activation triggered systemic MC activation. We then identified platelet activating factor (PAF) as the platelet-derived mediator stimulating MCs and, using chimeric animals with platelets defective in PAF generation or MCs lacking PAF receptor, defined the role of this platelet-MC interaction for vascular leakage, shock, and tissue inflammation. In application of these findings, we demonstrated that inhibition of platelet activation in modeled cardiac surgery blunted MC-dependent inflammation and tissue injury. Together, our work identifies a previously undefined mechanism of inflammatory augmentation, in which platelets trigger local and systemic responses through activation of perivascular MCs.

Thrombocytopenia After Cardiopulmonary Bypass Is Associated With Increased Morbidity and Mortality

BACKGROUND

Thrombocytopenia is a risk factor for morbidity and mortality in critically ill patients, and is common after cardiopulmonary bypass (CPB). In this study, we evaluate whether thrombocytopenia after CPB is an independent risk factor for postoperative morbidity and mortality.

METHODS

We retrospectively evaluated 1364 patients requiring CPB at the University of Colorado Hospital between January 2011 and May 2016. Platelet nadir, absolute change in platelets, and percent change in platelets were modeled as continuous variables. Patients with postoperative thrombocytopenia (defined a nadir <75 × 10³/μL within 72 hours) were also compared with patients without thrombocytopenia in a propensity-matched model. The primary outcome was in-hospital mortality, and secondary outcomes included postoperative infection, postoperative acute kidney injury (AKI), postoperative stroke, and prolonged intensive care unit (ICU) and hospital lengths of stay (LOS).

RESULTS

Postoperative thrombocytopenia occurred in 356 (26.0%) patients. In multivariable analysis, platelet nadir was significantly inversely associated with mortality (odds ratio [OR], 0.955; 95% confidence interval [CI], 0.934-0.975; P < .001), postoperative infection (OR, 0.992; 95% CI, 0.986-0.999; P = .03), AKI (all stage) (OR, 0.993; 95% CI, 0.988-0.998; P = .01), AKI (stage 3) (OR, 0.966; 95% CI, 0.951-0.982; P < .001), postoperative stroke (OR, 0.974; 95% CI, 0.956-0.992; P = .006), prolonged ICU stay (OR, 0.986; 95% CI, 0.981-0.991; P < .001), and hospital LOS (OR, 0.998; 95% CI, 0.997-0.999; P = .001). Percent change in platelets from baseline was also significantly associated with all primary and secondary outcomes.

CONCLUSIONS

Postoperative thrombocytopenia is independently associated with postoperative mortality, AKI, infection, stroke, and prolonged ICU and hospital LOS. Serial platelet monitoring may help identify patients at higher risk of postoperative complications. Further studies investigating strategies to reduce postoperative thrombocytopenia, including reducing CPB time, are needed.

Early Versus Delayed Stroke After Cardiac Surgery: A Systematic Review and Meta-Analysis

Background

Although it is traditionally regarded as a single entity, perioperative stroke comprises 2 separate phenomena (early/intraoperative and delayed/postoperative stroke). We aimed to systematically evaluate incidence, risk factors, and clinical outcome of early and delayed stroke after cardiac surgery.

Methods and Results

A systematic review (MEDLINE, EMBASE, Cochrane Library) was performed to identify all articles reporting early (on awakening from anesthesia) and delayed (after normal awakening from anesthesia) stroke after cardiac surgery. End points were pooled event rates of stroke and operative mortality and incident rate of late mortality. Thirty‐six articles were included (174 969 patients). The pooled event rate for early stroke was 0.98% (95% CI 0.79% to 1.23%) and was 0.93% for delayed stoke (95% CI 0.77% to 1.11%; P=0.68). The pooled event rate of operative mortality was 28.8% (95% CI 17.6% to 43.4%) for early and 17.9% (95% CI 14.0% to 22.7%) for delayed stroke, compared with 2.4% (95% CI 1.9% to 3.1%) for patients without stroke (P<0.001 for early versus delayed, and for perioperative stroke, early stroke, and delayed stroke versus no stroke). At a mean follow‐up of 8.25 years, the incident rate of late mortality was 11.7% (95% CI 7.5% to 18.3%) for early and 9.4% (95% CI 5.9% to 14.9%) for delayed stroke, compared with 3.4% (95% CI 2.4% to 4.8%) in patients with no stroke. Meta‐regression demonstrated that off‐pump was inversely associated with early stroke (β=−0.009, P=0.01), whereas previous stroke (β=0.02, P<0.001) was associated with delayed stroke.

Conclusions

Early and delayed stroke after cardiac surgery have different risk factors and impacts on operative mortality as well as on long‐term survival.

Thrombocytopenia and declines in platelet counts: predictors of mortality and outcome after mechanical thrombectomy

BACKGROUND AND PURPOSE

Acute ischemic stroke (AIS) has well-known risk factors. The role of platelets in patients treated using mechanical thrombectomy (MT) has not been studied. The aim of this study was to study if there is an association of initial thrombocytopenia (TP) and a decline of platelets counts (DPC) with the clinical outcomes, mortality and intracranial hemorrhage (ICH) rates in AIS patients treated with MT.

MATERIALS AND METHODS

In a case-control study consecutive MT-stroke patients were analyzed. A multivariate logistic regression model was used to test for good clinical outcome (mRS 90 days <= 2) and mortality adjusting for age, initial NIHSS, pretreatment with tPA, statins and platelet inhibitors, occlusion site, time from symptom onset to recanalization, initial TP (< 150 × 10⁹/L) and DPC (> 26%). Additionally, rates of ICH were compared.

RESULTS

Of 294 patients included, 9.6% had an initial TP and 23.8% a DPC > 26%. The mortality rate in patients with normal platelet counts was 26.1% vs. 48.3% (p = 0.002) in patients with initial TP with an aOR of 3.47 (CI 1.28-9.4, p = 0.005). No difference regarding the rate of good clinical outcome (p = 0.204) and ICH (p = 0.18) was observed. A DPC of more than 26% during the first 5 days of hospitalization predicted the rate of mortality (aOR 2.4 CI 1.14-5.04, p = 0.021) and the chances of a good clinical outcome (aOR 0.291 CI 0.128-0.666, p = 0.003) without significant differences of ICH rates (p = 0.735).

CONCLUSION

In AIS patients treated with MT an initial TP was independently associated with higher mortality rates and a marked DPC with higher mortality rates as well as poorer clinical outcomes.

Postoperative thrombocytopenia: why you should consider antiplatelet therapy?

PURPOSE OF REVIEW

This review addresses the role of platelets in perioperative ischemic complications involving the brain, kidneys, and gastrointestinal tract, and long-term survival in patients undergoing coronary artery bypass grafting surgery. Importantly, findings of several recent clinical studies will be discussed with emphasis on platelet activation and leukocyte inflammatory responses as important mediators of vascular microthrombosis and ischemic injury.

RECENT FINDINGS

Our recent findings suggest that in some patients, the hemostatic balance during and after surgery may shift toward a hypercoagulable state and contribute to acute organ failure.

SUMMARY

For over 6 decades, major postoperative complications after cardiac surgery have remained unchanged. The potential influence of microthrombosis involving platelets has been underappreciated and use of perioperative antiplatelet therapy remains very limited - primarily because of a culture of fear of bleeding.

Genome-Wide Association Study Links Receptor Tyrosine Kinase Inhibitor Sprouty 2 to Thrombocytopenia after Coronary Artery Bypass Surgery

INTRODUCTION

 Thrombocytopenia after cardiac surgery independently predicts stroke, acute kidney injury and death. To understand the underlying risks and mechanisms, we analysed genetic variations associated with thrombocytopenia in patients undergoing coronary artery bypass grafting (CABG) surgery.

MATERIALS AND METHODS

 Study subjects underwent isolated on-pump CABG surgery at Duke University Medical Center. Post-operative thrombocytopenia was defined as platelet count < 100 × 10⁹/L. Using a logistic regression model adjusted for clinical risk factors, we performed a genome-wide association study in a discovery cohort (n = 860) and validated significant findings in a replication cohort (n = 296). Protein expression was assessed in isolated platelets by immunoblot.

RESULTS

 A total of 63 single-nucleotide polymorphisms met a priori discovery thresholds for replication, but only 1 (rs9574547) in the intergenic region upstream of sprouty 2 (SPRY2) met nominal significance in the replication cohort. The minor allele of rs9574547 was associated with a lower risk for thrombocytopenia (discovery cohort, odds ratio, 0.45, 95% confidence interval, 0.30-0.67, p = 9.76 × 10^-5) with the overall association confirmed by meta-analysis (meta-p = 7.88 × 10^-6). Immunoblotting demonstrated expression of SPRY2 and its dynamic regulation during platelet activation. Treatment with a functional SPRY2 peptide blunted platelet extracellular signal-regulated kinase (ERK) phosphorylation after agonist stimulation.

CONCLUSION

 We identified the association of a genetic polymorphism in the intergenic region of SPRY2 with a decreased incidence of thrombocytopenia after CABG surgery. Because SPRY2-an endogenous receptor tyrosine kinase inhibitor-is present in platelets and modulates essential signalling pathways, these findings support a role for SPRY2 as a novel modulator of platelet responses after cardiac surgery.