Antithrombotic therapy management of adult and pediatric cardiac surgery patients

Clinical outcomes after inferior vena cava resection for malignant disease. A single center experience of 51 vena cava resections

BACKGROUND AND OBJECTIVE

For tumors involving inferior vena cava (IVC), surgery with complete resection remains the first line treatment. Management of IVC after resection, either ligation without reconstruction or primary reconstruction, is debated. Our study aimed to evaluate type of venous reconstruction, anticoagulation management and morbidity.

METHODS

A French single center database of patients who underwent partial or total circumferencial resection of the IVC for malignant disease was analyzed. Inclusion criteria were any oncologic procedure for a retroperitoneal neoplasm requiring concomitant resection of the IVC with or without venous reconstruction with prosthesis. Exclusion criteria were surgery before year 2000. Data were descriptive and reverse Kaplan Meier was used for follow-up calculation. The endpoints were the rate of prosthetic reconstruction, the use of anticoagulation and the post-operative outcomes.

RESULTS

Fifty - one patients were included with a median duration of follow-up of 54.8 months. The majority of patients were men (56.9%). Median age of the population was 44.1 years. Most of the patients underwent surgery for primary testicular cancer and for sarcoma. Complete IVC resections were performed in 46 (90,2%) patients, 32 having a concomitant prosthetic replacement. Eight patients underwent aortic resection in the same operative time. Postoperative morbidity was 33.3%. Post-operative anticoagulation was done in 24 patients. At 1 month, four patients developed thrombosis in the prosthesis.

CONCLUSIONS

IVC resections are feasible and safe. Venous reconstruction and postoperative management were planned according to the preoperative imaging and intraoperative findings. We propose a decision-tree for peri-operative management and anticoagulation.

Activated clotting time value as an independent predictor of postoperative bleeding and transfusion

OBJECTIVES

Activated clotting time (ACT) is commonly used to monitor anticoagulation during cardiac surgeries. Final ACT values may be essential to predict postoperative bleeding and transfusions, although ideal values remain unknown. Our aim was to evaluate the utility of ACT as a predictor of postoperative bleeding and transfusion use.

METHODS

Retrospective study (722 patients) submitted to surgery between July 2018-October 2021. We compared patients with final ACT < basal ACT and final ACT ≥ basal ACT and final ACT < 140 s with ≥140 s. Continuous variables were analysed with the Wilcoxon rank-sum test; categorical variables using Chi-square or Fisher's exact test. A linear mixed regression model was used to analyse bleeding in patients with final ACT < 140 and ≥140. Independent variables were analysed with binary logistic regression models to investigate their association with bleeding and transfusion.

RESULTS

Patients with final ACT ≥ 140 s presented higher postoperative bleeding than final ACT < 140 s at 12 h (P = 0.006) and 24 h (**P = 0.004). Cardiopulmonary bypass (CPB) time [odds ratio (OR) 1.009, 1.002-1.015, 95% confidence interval (CI)] and masculine sex (OR 2.842,1.721-4.821, 95% CI) were significant predictors of bleeding. Patients with final ACT ≥ 140 s had higher risk of UT (OR 1.81, 1.13-2.89, 95% CI; P = 0.0104), compared to final ACT < 140 s. CPB time (OR 1.019,1.012-1.026, 95% CI) and final ACT (OR 1.021,1.010-1.032, 95% CI) were significant predictors of transfusion. Female sex was a predictor of use of transfusion, with a probability for use of 27.23% (21.84-33.39%, 95% CI) in elective surgeries, and 60.38% (37.65-79.36%, 95% CI) in urgent surgeries, higher than in males.

CONCLUSIONS

Final ACT has a good predictive value for the use of transfusion. Final ACT ≥ 140 s correlates with higher risk of transfusion and increased bleeding. The risk of bleeding and transfusion is higher with longer periods of CPB. Males have a higher risk of bleeding, but females have a higher risk of transfusion.

Safety of Early Surgery in Hip Fracture Patients Taking Clopidogrel and/or Aspirin: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this study was to investigate the safety of early surgery in hip fracture patients who took clopidogrel and/or aspirin.

METHODS

A systematic search was conducted using databases, including PubMed/MEDLINE, Embase, Cochrane Library, and Web of Science, for studies relating to early arthroplasty or internal fixation for femoral neck fractures, intertrochanteric fractures, and subtrochanteric fractures in patients taking clopidogrel and/or aspirin. A total of 20 observational studies involving 3,077 patients were included in this meta-analysis, and analyzed in groups of early surgery versus delayed surgery, and clopidogrel and/or aspirin versus nonantiplatelet agents.

RESULTS

Patients in the clopidogrel and/or aspirin group who underwent early surgery had significantly more intraoperative blood loss than those in the non-antiplatelet group (mean difference = 17.96, 95% confidence interval [CI] [4.37, 31.55], P = .01), and patients in the clopidogrel and/or aspirin group had a lower overall incidence of complications after early surgery than those in the delayed surgery group (odds ratio = 0.26, 95% CI [0.14, 0.29], P < .001) and a shorter length of hospital stay (odds ratio = 0.26, 95% CI [0.14, 0.29], P < .001). There was no significant difference in postoperative mortality and other related indicators.

CONCLUSIONS

Early surgery in hip fracture patients taking clopidogrel and/or aspirin appears to be safe based on the available evidence and needs to be clarified by higher quality studies. However, the increased risk of cardiovascular events associated with discontinuation of clopidogrel or clopidogrel combined with aspirin dual antiplatelet therapy requires attention in the perioperative period.

Role of Radiology in Assessment of Postoperative Complications of Heart Transplantation

Heart transplantation is a pivotal treatment of end-stage heart failure, and recent advancements have extended median posttransplant life expectancy. However, despite the progress in surgical techniques and medical treatment, heart transplant patients still face complications such as rejection, infections, and drug toxicity. CT is a reliable tool for detecting most of these complications, whereas MR imaging is particularly adept at identifying pericardial pathologies and signs of rejection. Awareness of these nuances by radiologists, cardiologists, and surgeons is desired to optimize care, reduce morbidities, and enhance survival.

Pharmacokinetics of a microdosed cocktail of three direct oral anticoagulants in children with congenital heart defects: study protocol for a single-centre clinical trial (DOAC-Child)

INTRODUCTION

Direct oral anticoagulants (DOACs) are direct inhibitors of coagulation factor Xa and are frequently used in adults for different indications such as deep vein thrombosis or non-valvular atrial fibrillation. Paediatric patients might benefit as well from DOACs because the simplicity and convenience of their use is likely to decrease physical and psychological stress related to invasive procedures associated with phenprocoumon and heparin therapy. Thus, it is expected that the future use of DOACs will ultimately improve compliance and overall safety of anticoagulant therapies in paediatric populations. To assure safe and effective use the clinical pharmacology and pharmacokinetics (PK) of these drugs need to be evaluated in children.

METHODS AND ANALYSIS

This study is a single-centre, open-label, clinical trial in a paediatric population with non-cyanotic congenital heart defects. After having obtained informed consent from the parents, each participant will receive a single oral administration of a drinkable solution of a microdose cocktail of three FXa inhibitors consisting of apixaban (12.5 µg), rivaroxaban (12.5 µg), edoxaban (50 µg), plus a microdose of the two probe drugs midazolam (10 µg) and yohimbine (25 µg). Serial blood samples (n=up to 20) will be collected at specified time points before and up to 25 hours after cocktail administration. The primary PK endpoint will be the area under the plasma concentration time curve of apixaban, rivaroxaban and edoxaban. Secondary PK outcomes will be C_max, t_max, t_1/2, Cl/F and V_ss/F. Safety and tolerability of the microdose cocktail will be evaluated as well by a collection of adverse events.

ETHICS

This study has been approved by the responsible Ethics Committee of the Medical Faculty of Heidelberg University.

DISSEMINATION

Study results will be presented at international scientific meetings and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

EudraCT 2019-001759-38 16, DRKS00021455.

Effectiveness of Amiodarone in Preventing the Occurrence of Reperfusion Ventricular Fibrillation After the Release of Aortic Cross-Clamp in Open-Heart Surgery Patients: A Meta-Analysis

Objective

To evaluate the efficiency of amiodarone in preventing the occurrence of reperfusion ventricular fibrillation (RVF) after aortic cross-clamp (ACC) release in patients undergoing open-heart surgery.

Methods

We searched the Web of Science, Cochrane Library, EMBASE, and PubMed databases through January 2021 for relevant studies addressing the efficacy of amiodarone in preventing RVF after ACC release in patients undergoing cardiac surgery. A complete statistical analysis was performed using RevMan 5.3. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated to express the results of dichotomous outcomes using random or fixed-effect models. The chi-square test and I² test were used to calculate heterogeneity.

Results

Seven studies (856 enrolled patients; 311 in the amiodarone group, 268 in the lidocaine group, and 277 in the placebo group) were selected for the meta-analysis. The incidence of RVF was significantly decreased in the amiodarone group compared to the placebo group (RR = 0.69, 95%CI: 0.50–0.94, P = 0.02). However, amiodarone and lidocaine did not confer any significant difference (RR = 0.98, 95%CI: 0.61–1.59, P = 0.94). The percentage of patients requiring electric defibrillation counter shocks (DCSs) did not confer any significant difference between patients administered amiodarone and lidocaine or placebo (RR = 1.58, 95%CI: 0.29–8.74, P = 0.60; RR = 0.55, 95%CI: 0.27–1.10, P = 0.09; respectively).

Conclusions

Amiodarone is more effective than a placebo in preventing RVF after ACC release in cardiac surgery. However, the amiodarone group required the same number of electrical DCSs to terminate RVF as the lidocaine or placebo groups.

Perioperative Guidelines on Antiplatelet and Anticoagulant Agents: 2022 Update

Purpose of Review

Multiple guidelines and recommendations have been written to address the perioperative management of antiplatelet and anticoagulant drugs. In this review, we evaluated the recent guidelines in non-cardiac, cardiac, and regional anesthesia. Furthermore, we focused on unresolved problems and novel approaches for optimized perioperative management.

Recent Findings

Vitamin K antagonists should be stopped 3 to 5 days before surgery. Preoperative laboratory testing is recommended. Bridging therapy does not decrease the perioperative thromboembolic risk and might increase perioperative bleeding risk. In patients on direct-acting oral anticoagulants (DOAC), a discontinuation interval of 24 and 48 h in those scheduled for surgery with low and high bleeding risk, respectively, has been shown to be saved. Several guidelines for regional anesthesia recommend a conservative interruption interval of 72 h for DOACs before neuraxial anesthesia. Finally, aspirin is commonly continued in the perioperative period, whereas potent P2Y12 receptor inhibitors should be stopped, drug-specifically, 3 to 7 days before surgery.

Summary

Many guidelines have been published from various societies. Their applicability is limited in emergent or urgent surgery, where novel approaches might be helpful. However, their evidence is commonly based on small series, case reports, or expert opinions.

Factors Influencing Reintervention Following Ductal Artery Stent Implantation for Ductal-Dependent Pulmonary Blood Flow: Results From the Congenital Cardiac Research Collaborative

BACKGROUND

Stenting of the patent ductus arteriosus (PDA) is an established palliative option for infants with ductal-dependent pulmonary blood flow. Following initial palliation, reintervention on the PDA stent is common, but risk factors have not been characterized.

METHODS

Infants with ductal-dependent pulmonary blood flow palliated with PDA stent between 2008 and 2015 were reviewed within the Congenital Cardiac Research Collaborative. Rates and risk factors for reintervention were analyzed.

RESULTS

Among 105 infants who underwent successful PDA stenting, 41 patients (39%) underwent a total of 53 reinterventions on the PDA stent, with all but one occurring within 6 months of the initial intervention. Stent redilation constituted the majority of reintervention (n=35; 66%) followed by additional stent placement (n=11; 21%) and surgical shunt placement (n=7; 13%). The majority of reintervention was nonurgent, and there were no deaths during the reintervention procedure. All but one reintervention occurred within 6 months of the initial procedure. On univariate analysis, risk factors for reintervention included anticipated single-ventricle physiology, lack of prior balloon pulmonary valvuloplasty, use of drug-eluting stent, and increased ductal tortuosity.

CONCLUSIONS

In infants with ductal-dependent pulmonary blood flow palliated with PDA stent implantation, reintervention is common, can be performed safely, and is associated with both anatomic/procedural factors and anticipated final physiology.

ICU Nurses-An Impact Factor on Patient Turnover in Cardiac Surgery in Western Denmark?

OBJECTIVE

The aim of this study was to describe changes in performance indicators such as length of stay [LOS] in the intensive care unit [ICU] and ventilation time, during the last six years in an attempt to identify associations between patient and systemic performance indicators, including the impact of nurse turnover.

DESIGN

A retrospective study of prospectively registered data (2013-2018). Propensity- score matching was performed to establish comparable groups.

SETTING

Three Danish university hospitals.

PARTICIPANTS

The study included a total of 12,404 adult cardiac surgical patients registered in the Western Denmark Heart Registry. The cohort was divided into an "early" group (2013-2016) and a "late" group (2017-2018).

INTERVENTIONS

An analysis of dynamics in patient indicators and systemic performance indicators, including the impact from selected performance parameters and nurse turnover.

MEASUREMENTS AND MAIN RESULTS

Comorbidity, calculated from the European System for Cardiac Operative Risk Evaluation, and the mean age were stable in the study period. Strong predictors of long LOS in the ICU included postoperative use of inotropes, re-exploration surgery, high postoperative drainage, and the "late" time group. Time parameters (relative risks) were all significantly longer in the "late" time group": ventilation time 1.21 (1.05-1.39), length of stay ICU 1.28 (1.11-1.48), and in-hospital time 1.36 (1.19-1.57). ICU nurse turnover increased from four (2013-2014) to 52 (2017-2018).

CONCLUSION

No single patient factor, such as age or comorbidity, could explain the decrease in patient turnover in the ICU. In the same period, the turnover of ICU nurses increased. Patient turnover is complex and affected by a mix of patient and systemic performance factors.

Thromboelastography-Platelet Mapping Allows Safe and Earlier Urgent Coronary Artery Bypass Grafting

BACKGROUND

Current STS guidelines recommend delaying CABG for several days or performing platelet function testing in stable patients who received P2Y12 inhibitors. Our program routinely uses thromboelastography-platelet mapping (TEG-PM) to expedite CABG in P2Y12 non-responders (NR). We hypothesize that P2Y12 NR had no difference in LOS to surgery and blood product transfusion compared to patients undergoing urgent inpatient CABG not treated with a P2Y12 inhibitor.

METHODS

A total of 221 patients from 2015-2019 were P2Y12 NR based on TEG-PM result of < 50% ADP inhibition. The control group was 232 consecutive patients who also had urgent inpatient CABG but were not treated pre-operatively with a P2Y12 inhibitor. Exclusion criteria were identical between groups.

RESULTS

Sixty-seven percent of inpatient CABG patients who were treated pre-operatively with a P2Y12 inhibitor were NR. The mean number of days from cardiac surgical consultation to CABG in the TEG-PM NR group was 1.6 ± 0.1 versus 2.1 ± 0.1 in the control group (p<0.01). The mean total number of blood product units transfused was 1.6 ± 0.2 in the TEG-PM NR group versus 1.6 ± 0.4 in controls (p=0.91).

CONCLUSIONS

Our results demonstrate a very high incidence of P2Y12 non-responders in patients undergoing urgent CABG at our program. These patients underwent surgery at least 3 days earlier than STS recommendations and common practice with no difference in transfusion requirement. Routine use of TEG-PM to identify P2Y12 NR can safely decrease pre-operative hospital LOS and associated cost and improve resource utilization and patient satisfaction.

Managing the coagulopathy associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has allowed for significant surgical advancements, but accompanying risks can be significant and must be expertly managed. One of the foremost risks is coagulopathic bleeding. Increasing levels of bleeding in cardiac surgical patients at the time of separation from CPB are associated with poor outcomes and mortality. CPB-associated coagulopathy is typically multifactorial and rarely due to inadequate reversal of systemic heparin alone. The components of the bypass circuit induce systemic inflammation and multiple disturbances of the coagulation and fibrinolytic systems. Anticipating coagulopathy is the first step in managing it, and specific patient and procedural risk factors have been identified as predictors of excessive bleeding. Medication management pre-procedure is critical, as patients undergoing cardiac surgery are commonly on anticoagulants or antiplatelet agents. Important adjuncts to avoid transfusion include antifibrinolytics, and perfusion practices such as red cell salvage, sequestration, and retrograde autologous priming of the bypass circuit have varying degrees of evidence supporting their use. Understanding the patient's coagulation status helps target product replacement and avoid larger volume transfusion. There is increasing recognition of the role of point-of-care viscoelastic and functional platelet testing. Common pitfalls in the management of post-CPB coagulopathy include overdosing protamine for heparin reversal, imperfect laboratory measures of thrombin generation that result in normal or near-normal laboratory results in the presence of continued bleeding, and delayed recognition of surgical bleeding. While challenging, the effective management of CPB-associated coagulopathy can significantly improve patient outcomes.

Collaborative Review: Factors Influencing Treatment Decisions for Patients with a Localized Solid Renal Mass

CONTEXT

With the addition of active surveillance and thermal ablation (TA) to the urologist's established repertoire of partial (PN) and radical nephrectomy (RN) as first-line management options for localized renal cell carcinoma (RCC), appropriate treatment decision-making has become increasingly nuanced.

OBJECTIVE

To critically review the treatment options for localized, nonrecurrent RCC; to highlight the patient, renal function, tumor, and provider factors that influence treatment decisions; and to provide a framework to conceptualize that decision-making process.

EVIDENCE ACQUISITION

A collaborative critical review of the medical literature was conducted.

EVIDENCE SYNTHESIS

We identify three key decision points when managing localized RCC: (1) decision for surveillance versus treatment, (2) decision regarding treatment modality (TA, PN, or RN), and (3) decision on surgical approach (open vs minimally invasive). In evaluating factors that influence these treatment decisions, we elaborate on patient, renal function, tumor, and provider factors that either directly or indirectly impact each decision point. As current nomograms, based on preselected patient datasets, perform poorly in prospective settings, these tools should be used with caution. Patient decision aids are an underutilized tool in decision-making.

CONCLUSIONS

Localized RCC requires highly nuanced treatment decision-making, balancing patient- and tumor-specific clinical variables against indirect structural influences to provide optimal patient care.

PATIENT SUMMARY

With expanding treatment options for localized kidney cancer, treatment decision is highly nuanced and requires shared decision-making. Patient decision aids may be helpful in the treatment discussion.

Hemostatic Challenges in Pediatric Critical Care Medicine-Hemostatic Balance in VAD

Ventricular assist devices (VAD) are used more in children. Safe and effective anticoagulation is required for successful management of children supported with ventricular assist devices. Developmental hemostasis, device hemocompatibility, plastic to body ratio, surgical variable techniques, lack of knowledge on pharmacokinetics of anticoagulants, and wide variability in anticoagulation protocols have all contributed to increased incidence of bleeding and thromboembolic complications. New collaborative learning networks, such as the ACTION network, provide opportunities to define best practices, optimize, and reduce anticoagulation related adverse events. ACTION was established Dec 2017. It consists of expert clinicians in heart failure, as well as researchers, parents, and patients, with goals to improve outcomes, share data, improve education and standard practice for children with heart failure (, n.d). Changes in pediatric VAD anticoagulation strategy from using mainly heparin to DTI such as bivalirudin have helped reduce bleeding and clotting complications.

Extracardiac Complications in Intensive Care Units after Surgical Repair for Congenital Heart Disease: Imaging Review with a Focus on Ultrasound and Radiography

Pediatric patients show various extracardiac complications after cardiovascular surgery, and radiography and ultrasound are routinely performed in the intensive care unit to detect and evaluate these complications. This review presents images of these complications, sonographic approach, and timing of occurrence that are categorized based on their extracardiac locations and include complications pertaining to the central nervous system, mediastinum, thorax and lung parenchyma, diaphragm, liver and biliary system, and kidney along with pleural effusion and iatrogenic complications. This pictorial review will make it easier for medical doctors in intensive care units to identify and manage various extracardiac complications in pediatric patients after cardiovascular surgery.

Novel use of cangrelor in pediatrics: A pilot cohort study demonstrating use in ventricular assist devices

Thromboembolic events and bleeding are major sources of morbidity among pediatric patients supported on a ventricular assist device (VAD). Pharmacokinetics and pharmacodynamics of enteral antiplatelet agents are affected and variable due to erratic enteral absorption in end-stage heart failure and VAD circulation. Additionally, 20%-40% of the population are poor metabolizers of clopidogrel, a prodrug, making cangrelor an alternative when antiplatelet therapy is crucial. Cangrelor has been used effectively and safely for short durations in adults during percutaneous coronary interventions, but the use of cangrelor is still under investigation in pediatrics. This case series utilized cangrelor, a novel short-acting, reversible, intravenous P2Y₁₂ platelet inhibitor in managing pediatric patients supported with a VAD. We performed a retrospective, single-center review of patients admitted to a tertiary medical center with end-stage heart failure requiring mechanical circulatory support and concomitant cangrelor administration between January 2019 and March 2020. Platelet function testing, cangrelor dose, bleeding complications, thromboembolic events, and frequency of circuit interventions during the use of cangrelor were recorded. Optimal platelet reactivity, defined as P2Y₁₂ < 180 platelet reaction units (PRU), was measured with serial point-of-care testing (VerifyNow). Seven patients, median age of 4.9 years, met the above criteria. Three patients had a diagnosis of complex congenital heart disease. Four patients had dilated or restrictive cardiomyopathy. All patients were on continuous flow VADs. The median VAD duration was 84.5 days (IQR 61.5-103). The median duration on cangrelor was 43 days (IQR 8-70). The median cangrelor dose to reach the therapeutic threshold was 0.75 μg/kg/min with the mean P2Y₁₂ , while on cangrelor of 164.75 PRU. Bleeding complications included mild gastrointestinal bleeding and hematuria. There was one patient with pump thrombosis requiring intervention. There were no cerebrovascular events while on cangrelor. We report the first successful long-term use of cangrelor in pediatric patients. The reversibility and short half-life of cangrelor make it a feasible antiplatelet agent in selected patients. This data supports the use of cangrelor in children as a viable antiplatelet option; with minimal bleeding complications and no cerebrovascular events demonstrated in this cohort.

Treatment of gastrointestinal bleeding in left ventricular assist devices: A comprehensive review

Left ventricular assist devices (LVAD) are increasingly become common as life prolonging therapy in patients with advanced heart failure. Current devices are now used as definitive treatment in some patients given the improved durability of continuous flow pumps. Unfortunately, continuous flow LVADs are fraught with complications such as gastrointestinal (GI) bleeding that are primarily attributed to the formation of arteriovenous malformations. With frequent GI bleeding, antiplatelet and anticoagulation therapies are usually discontinued increasing the risk of life-threatening events. Small bowel bleeds account for 15% as the source and patients often undergo multiple endoscopic procedures. Treatment strategies include resuscitative measures and endoscopic therapies. Medical treatment is with octreotide. Novel treatment options include thalidomide, angiotensin converting enzyme inhibitors/angiotensin II receptor blockers, estrogen-based hormonal therapies, doxycycline, desmopressin and bevacizumab. Current research has explored the mechanism of frequent GI bleeds in this population, including destruction of von Willebrand factor, upregulation of tissue factor, vascular endothelial growth factor, tumor necrosis factor-α, tumor growth factor-β, and angiopoetin-2, and downregulation of angiopoetin-1. In addition, healthcare resource utilization is only increasing in this patient population with higher admissions, readmissions, blood product utilization, and endoscopy. While some of the novel endoscopic and medical therapies for LVAD bleeds are still in their development stages, these tools will yet be crucial as the number of LVAD placements will likely only increase in the coming years.

Anticoagulation management strategies in heart transplantation

Anticoagulation before, during, and after heart transplantation (HT) presents unique challenges to clinicians. Bleeding and thrombotic morbidity continues to affect this patient population throughout all phases of the HT journey. Reversal is commonly required since patients are commonly bridged to HT with left ventricular assist devices, which require chronic anti platelet and anticoagulation. Caution must be exercised in patients requiring cardiopulmonary bypass during surgery who are at risk of complications from heparin induced thrombocytopenia. The reported incidence of venous thromboembolism following HT is high, particularly during the first post-HT year, most likely due to surgery, biopsies, specific immunosuppression (mTOR inhibitors) and immobilization. It is crucial to maintain long-term oral anticoagulation after the first venous thromboembolism event, especially when risk factors exist. A major issue, and one for which there remains considerable debate, is the optimal treatment of such complications, particularly upper extremity venous thrombosis. For both warfarin and the thrombin inhibitors or Factor Xa inhibitors, the clinician must determine potential drug interactions based on the HT drug regimen, and then develop a patient-specific management strategy.

The association between platelet dysfunction and adverse outcomes in cardiac surgical patients

Haemostatic activation during cardiopulmonary bypass is associated with prothrombotic complications. Although it is not possible to detect and quantify haemostatic activation directly, platelet dysfunction, as measured with point-of-care-assays, may be a useful surrogate. In this study, we assessed the association between cardiopulmonary bypass-associated platelet dysfunction and adverse outcomes in 3010 cardiac surgical patients. Platelet dysfunction, as measured near the end of the rewarming phase of cardiopulmonary bypass, was calculated as the proportion of non-functional platelets after activation with collagen. Logistic regression and multivariable analyses were applied to assess the relationship between platelet dysfunction and a composite of in-hospital death; myocardial infarction; stroke; deep vein thrombosis or pulmonary embolism; and acute kidney injury (greater than a two-fold increase in creatinine). The outcome occurred in 251 (8%) of 3010 patients. The median (IQR [range]) percentage platelet dysfunction was less for those without the outcome as compared with those with the outcome; 14% (8-28% [1-99%]) vs. 19% (11-45% [2-98%]), p < 0.001. After risk adjustment, platelet dysfunction was independently associated with the composite outcome (p < 0.001), such that for each 1% increase in platelet dysfunction there was an approximately 1% increase in the composite outcome (OR 1.012; 95%CI 1.006-1.018). This exploratory study suggests that cardiopulmonary bypass-associated platelet dysfunction has prognostic value and may be a useful clinical measure of haemostatic activation in cardiac surgery.