Outcomes of Coronary Artery By-Pass Grafting Under Dual Antiplatelet Therapy in ST Elevated Myocardial Infarction

Patients with recent myocardial infarction (MI) or percutaneous coronary interventions (PCI) have a higher ischemic risk in addition to perioperative bleeding risk when undergoing coronary artery bypass grafting (CABG). Data regarding preoperative dual antiplatelet therapy (DAPT) failed to create a clear recommendation. In the present study, we assessed the relationship between preoperative DAPT use and adverse outcomes, particularly in ST-elevation MI (STEMI) patients. We retrospectively analyzed 748 consecutive patients with STEMI who underwent subsequent CABG surgery. Patients were divided into 2 groups: those on DAPT up to the day before CABG and those discontinued DAPT >5 days before CABG. Predictors of in-hospital mortality and major bleeding were analyzed by multivariate analysis. Preoperative DAPT was not associated with in-hospital mortality (Odds Ratio (OR):1.81; 95% Confidence Interval (CI): .89-3.68, P = .10) and major bleeding (OR: 1.15; 95% CI: .63-2.08, P = .65) after multivariate analysis. However, glycoprotein (Gp) 2b/3a inhibitors were independently associated with higher major bleeding rates. Age, shock, and EF (ejection fraction) <30% were associated with in-hospital mortality. Previous MI, Gp 2b/3a inhibitors, and EF <30% were predictors of major bleeding. In conclusion, there were no association between pre-CABG DAPT use and in-hospital mortality and major bleeding.

Coronary artery bypass grafting after acute ST-elevation myocardial infarction

OBJECTIVES

The study objectives were to describe the trends and outcomes of isolated coronary artery bypass grafting after ST-elevation myocardial infarction using a nationwide database.

METHODS

We queried the 2002-2016 National Inpatient Sample database for hospitalized patients with ST-elevation myocardial infarction who underwent isolated coronary artery bypass grafting. We report temporal trends, predictors, and outcomes of coronary artery bypass grafting in the early (2002-2010) and recent (2011-2016) cohorts.

RESULTS

Of 3,347,470 patients hospitalized for ST-elevation myocardial infarction, 7.7% underwent isolated coronary artery bypass grafting. The incidence of isolated coronary artery bypass grafting after ST-elevation myocardial infarction decreased over time (9.2% in 2002 vs 5.5% in 2016, P_trend < .001), whereas perioperative crude in-hospital mortality did not change (5.1% in 2002 vs 4.2% in 2016, P_trend = .66), coinciding with an increase in the burden of comorbidities. There was an increase in performing isolated coronary artery bypass grafting on hospitalization day 3 or more, as well as an increase in the use of mechanical support devices and precoronary artery bypass grafting percutaneous coronary intervention. In the early cohort, isolated coronary artery bypass grafting on days 1 and 2 was associated with higher in-hospital mortality. In the recent cohort, coronary artery bypass grafting on day 2 had similar in-hospital mortality compared with day 3 or more and lower rates of acute kidney injury, ischemic stroke, ventricular arrhythmia, and length of hospital stay.

CONCLUSIONS

In this nationwide analysis, there has been a decline in the use of isolated coronary artery bypass grafting after ST-elevation myocardial infarction. Isolated coronary artery bypass grafting on day 1 was performed in sicker patients and was associated with higher in-hospital mortality than coronary artery bypass grafting performed on day 3 or more. In the recent cohort, isolated coronary artery bypass grafting on day 2 had similar in-hospital mortality compared with day 3 or more.

P2Y12 inhibitor pretreatment in patients with nonST-segment elevation acute coronary syndrome: A meta-analysis

BACKGROUND

The 2020 European Society of Cardiology guidelines do not recommend pretreatment for nonST-segment elevation myocardial infarction (NSTEMI) patients with unclear coronary anatomy, which is inconsistent with our routine preoperative approach to loading P2Y12 receptor inhibitors (e.g., preoperative loading of 300 mg of clopidogrel).

OBJECTIVES

The purpose of our study was to compare the safety and effectiveness of P2Y12 inhibitors administered before coronary angiography or at least before percutaneous coronary intervention (PCI) with during or after PCI.

METHODS

Cochrane, PubMed, and Embase databases were searched. The primary effect endpoint and safety endpoint were any-cause death and major bleeding, respectively. Major adverse cardiovascular events, myocardial infarction and revascularization were also analyzed.

RESULTS

Our search identified 9 trials. P2Y12 inhibitor pretreatment was associated with lower death from any cause (OR 0.62, 95% CI 0.53-0.72, P < 0.00001) without increasing the risk of bleeding (OR 1.02, 95% CI 0.80-1.30, P = 0.89). However, prasugrel or ticagrelor pretreatment was not associated with a lower risk of mortality (OR 0.70, 95% CI 0.31-1.59, P = 0.40) and increased the risk of bleeding (OR 1.67, 95% CI 1.10-2.54, P = 0.02).

CONCLUSIONS

In summary, clopidogrel pretreatment was associated with significantly lower mortality, major adverse cardiovascular events, myocardial infarction and revascularization with no increase in major bleeding. However, these advantages were not observed with prasugrel or ticagrelor pretreatment.

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.

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.

Platelet Reactivity in Patients With Acute Coronary Syndromes Awaiting Surgical Revascularization

BACKGROUND

Dual antiplatelet therapy is recommended for patients with acute coronary syndromes (ACS). Approximately 10% to 15% of these patients will undergo coronary artery bypass graft (CABG) surgery for index events, and current guidelines recommend stopping clopidogrel at least 5 days before CABG. This waiting time has clinical and economic implications.

OBJECTIVES

This study aimed to evaluate if a platelet reactivity-based strategy is noninferior to standard of care for 24-h post-CABG bleeding.

METHODS

In this randomized, open label noninferiority trial, 190 patients admitted with ACS with indications for CABG and on aspirin and P2Y₁₂ receptor inhibitors, were assigned to either control group, P2Y₁₂ receptor inhibitor withdrawn 5 to 7 days before CABG, or intervention group, daily measurements of platelet reactivity by Multiplate analyzer (Roche Diagnostics GmbH, Vienna, Austria) with CABG planned the next working day after platelet reactivity normalization (pre-defined as ≥46 aggregation units).

RESULTS

Within the first 24 h of CABG, the median chest tube drainage was 350 ml (interquartile range [IQR]: 250 to 475 ml) and 350 ml (IQR: 255 to 500 ml) in the intervention and control groups, respectively (p for noninferiority <0.001). The median waiting period between the decision to undergo CABG and the procedure was 112 h (IQR: 66 to 142 h) and 136 h (IQR: 112 to 161 h) (p < 0.001), respectively. In the intention-to-treat analysis, a 6.4% decrease in the median in-hospital expenses was observed in the intervention group (p = 0.014), with 11.2% decrease in the analysis per protocol (p = 0.003).

CONCLUSIONS

A strategy based on platelet reactivity-guided is noninferior to the standard of care in patients with ACS awaiting CABG regarding peri-operative bleeding, significantly shortens the waiting time to CABG, and decreases hospital expenses. (Evaluation of Platelet Aggregability in the Release of CABG in Patients With ACS With DAPT; NCT02516267).

Factors associated with excessive bleeding following elective on-pump coronary artery bypass grafting

INTRODUCTION

Excessive bleeding following cardiac surgery is associated with worse outcomes. We aimed to analyze preoperative and operative factors associated with excessive bleeding in coronary artery bypass patients to better understand which patients are under increased risk.

METHODS

The study was conducted as an observational study in a tertiary center for cardiac surgery by retrospective analysis of the hospital database. Patients were grouped according to chest tube output within the postoperative 24 h. Patients in the 4th percentile of chest tube output per kilogram were categorized as having excessive bleeding. Patients with excessive bleeding were compared with the other patients for preoperative and operative factors. Factors significant in univariate analysis were carried onto the multivariate analysis.

RESULTS

Patients with excessive bleeding were more likely to be males (91.4% vs. 78.7%, p = .002), have lower body mass index (BMI) (27.4 vs. 29.2, p < .001), and low platelets (6.9% vs. 1.5%, p = .006). Cardiopulmonary bypass (101.8 vs. 110.9 min, p = .022) time was longer in the excessive bleeding group. Patients with excessive bleeding were more likely to have more than three vessels revascularized. Male sex, lower BMI, low platelets, and longer cardiopulmonary bypass time were independently associated with increased bleeding.

CONCLUSION

Male sex, lower BMI, low platelet count, and longer cardiopulmonary bypass time are associated with extensive bleeding after elective coronary artery bypass surgery (CABG). Patients with higher bleeding risk should be identified preoperatively to account for adverse outcomes after CABG.

Thromboelastography Platelet Mapping—A Useful Preoperative Tool to Reduce Transfusion Requirement by Determining Timing of Coronary Artery Bypass Graft Surgery in Patients taking Dual Antiplatelet Medication: A Pilot Study from Eastern India

In this pilot study, we proposed an algorithm to use thromboelastography platelet mapping (TEG-PM) as an effective preoperative platelet function assessment tool in coronary artery bypass graft surgery (CABG) to reduce the transfusion requirement by determining timing of surgery in patients who are on dual antiplatelet therapy (DAPT). Total 15 elective CABG patients who were receiving DAPT were tested by TEG-PM assay after 72 hours’ stoppage of both medications. Four patients who had < 50% inhibition with agonists (arachidonic acid [AA] and adenosine diphosphate [ADP]) were operated within 24 hours of assay. Eight patients who had > 70% inhibition with AA/ADP, surgery was deterred till 48 hours, and 3 patients with > 50% but < 70% inhibition were operated within 24 hours after preoperative prophylactic platelet transfusion. Transfusion requirement was recorded and compared with the previous transfusion data for CABG cases operated without TEG-PM. Distribution of ADP inhibition was 67.54 ± 30.03% and AA inhibition was 60.69 ± 30.14%, showing a variable offset of the effect of both medications starting after 72 hours of cessation. Overall transfusion requirement was decreased by using TEG-PM algorithm. Preoperative platelet function testing to determine the timing of surgery by TEG-PM assay in DAPT-treated patients may be a useful strategy to reduce transfusion requirement in CABG.

Point-of-Care Platelet Function Monitoring: Implications for Patients With Platelet Inhibitors in Cardiac Surgery

Although most physicians are comfortable managing the limited anticoagulant effect of aspirin, the recent administration of potent P2Y₁₂ receptor inhibitors in patients undergoing cardiac surgery remains a dilemma. Guidelines recommend discontinuation of potent P2Y₁₂ inhibitors 5- to- 7 days before surgery to reduce the risk of postoperative hemorrhage. Such a strategy might not be feasible before urgent surgery, due to ongoing myocardial ischemia or in patients at high risk for thromboembolic events. Recently, different point-of-care devices to assess functional platelet quality have become available for clinical use. The aim of this narrative review was to evaluate the implications and potential benefits of platelet function monitoring in guiding perioperative management and therapeutic options in patients treated with antiplatelets, including aspirin or P2Y₁₂ receptor inhibitors, undergoing cardiac surgery. No objective superiority of one point-of-care device over another was found in a large meta-analysis. Their accuracy and reliability are generally limited in the perioperative period. In particular, preoperative platelet function testing has been used to assess platelet contribution to bleeding after cardiac surgery. However, predictive values for postoperative hemorrhage and transfusion requirements are low, and there is a significant variability between and within these tests. Further, platelet function monitoring has been used to optimize the preoperative waiting period after cessation of dual antiplatelet therapy before urgent cardiac surgery. Furthermore, studies assessing their value in therapeutic decisions in bleeding patients after cardiac surgery are scarce. A general and liberal use of perioperative platelet function testing is not yet recommended.

When is the optimal time to discontinue clopidogrel before in-hospital coronary bypass surgery? A closer look at the current literature

BACKGROUND

Clopidogrel and other P2Y12 inhibitors have become the standard of care among patients presenting with acute coronary syndromes. A substantial proportion of these patients require surgical revascularization during index hospitalization.

HYPOTHESIS

Guidelines recommend a 5-day waiting period off clopidogrel before coronary artery bypass grafting (CABG) to reduce hemorrhagic complications. These recommendations are not routinely followed in clinical practice, while recent studies also propose shorter waiting periods off clopidogrel for patients awaiting in-hospital CABG.

METHODS

A preliminary PubMed search was conducted using the following MeSH terms under the publication type "Hemorrhage:" "Clopidogrel," AND "Coronary Artery Bypass." Relevant studies and guidelines were then reviewed and selected based on a predetermined criteria. Studies that formulated the current recommendations for stopping clopidogrel preoperative to CABG are discussed in detail this review.

RESULTS

A comprehensive review of recent evidence illustrates mixed bleeding and transfusion outcomes among CABG patients with preoperative exposure to clopidogrel in less than 5 days.

CONCLUSIONS

The optimal discontinuation time of clopidogrel before CABG is still poorly defined. The recommendation of a 5-day washout period for clopidogrel should be reconsidered to be on par with current clinical practice.

Dual antiplatelet therapy up to the time of non-elective coronary artery bypass grafting with prophylactic platelet transfusion: is it safe?

Background

Guidelines suggest that patients discontinue Clopidogrel at least 5 days prior to coronary artery bypass grafting (CABG). Those with acute coronary syndrome (ACS) are at high risk for myocardial infarction (MI) if not treated with dual antiplatelet therapy (DAPT). We sought to assess pre and post-operative outcomes of patients maintained on Clopidogrel and aspirin up to the time of surgery and compare them with those on aspirin alone.

Methods

From the cardiac surgery database, 240 patients were retrospectively registered between January and May 2017. There were 126 patients with ACS who underwent CABG on DAPT (Clopidogrel group [CG]) and 114 patients who underwent elective CABG on aspirin alone (control). The CG received intraoperative prophylactic platelet transfusion (PPT). Demographics, comorbidities, and laboratory data were prospectively entered at the time of surgery and were subsequently retrieved for analysis. Per and postoperative findings were identified and compared between both groups.

Results

The cohort consisted of 240 patients (mean age 61 years, 81.3% were male, SD ± 9.58). Patients in the CG were younger (Median 57 vs. 63, P-value 0.001), and with male predominance (86% versus 75%, P-value 0.028). In addition, they had less prevalence for diabetes and renal failure as compared to control (P-values 0.003, and 0.005, respectively). There were no significant differences between both groups in number of vessels grafts, duration of on-pump and aortic clamp. Hematologic laboratory data had also similar baseline values. The CG had similar bleeding rate, redo surgery and in-hospital death (P-values non-significant), however more infection and total hospital stay as compared to control (p-values 0.048 and 0.001).

Conclusion

Patients who are at increased risk for MI can be maintained on DAPT up to the time of CABG because surgery is safe when patients are offered PPT.

Modern Management of ST-Segment Elevation Myocardial Infarction

Disruption of intracoronary plaque with thrombus formation resulting in severe or total occlusion of the culprit coronary artery provides the pathophysiologic foundation for ST-segment elevation myocardial infarction (STEMI). Management of STEMI focuses on timely restoration of coronary blood flow along with antithrombotic therapies and secondary prevention strategies. The purpose of this review is to discuss the epidemiology, pathophysiology, and diagnosis of STEMI. In addition, the review will focus on guideline-directed therapy for these patients and review potential associated complications.

Low platelet activity predicts 30 days mortality in patients undergoing heart surgery

Despite advanced techniques and improved clinical outcomes, patient survival following coronary artery bypass grafting (CABG) is still a major concern. Therefore, predicting future CABG mortality represents an unmet medical need and should be carefully explored. The objective of this study is to assess whether pre-CABG platelet activity corresponds with 30 days mortality post-CABG. Retrospective analyses of platelet biomarkers and death at 30 days in 478 heart surgery patients withdrawn from aspirin or/and clopidogrel. Platelet activity was assessed prior to CABG for aspirin (ASPI-test) with arachidonic acid and clopidogrel (ADP-test) utilizing Multiplate impedance aggregometer. Most patients (n = 198) underwent conventional CABG, off-pump (n = 162), minimally invasive (n = 30), artificial valve implantation (n = 48) or valves in combination with CABG (n = 40). There were 22 deaths at 30 days, including 10 in-hospital fatalities. With the cut-off value set below 407 area under curve (AUC) for the ASPI-test, the 30-day mortality was 5.90% for the lower cohort and 2.66% for patients with significantly higher platelet reactivity (P = 0.038). For the ADP-test with a cut-off at 400AUC, the 30-day mortality was 9.68% for the lower cohort and 3.66% for patients with higher platelet reactivity, representing a borderline significant difference (P = 0.046). Aside from the platelet indices, patients who received red blood cell (RBC) concentrate had a highly significant (P < 0.0001) risk of death at 30 days. Both aspirin and clopidogrel tests were useful in predicting 30 days mortality following heart surgery, suggesting the danger of diminished platelet activity prior to CABG in such high-risk patients. These preliminary evidence supports early discontinuation of antiplatelet therapy for elective CABG and requires adequately powered randomized trials to test the hypothesis and potentially improve survival.

Culprit Vessel Revascularization Prior to Diagnostic Angiography as a Strategy to Reduce Delays in Primary Percutaneous Coronary Intervention: A Propensity-Matched Analysis

BACKGROUND

Delays are important markers of quality of care in primary percutaneous coronary intervention. There is scarce data on the impact of obtaining a complete diagnostic angiography before primary percutaneous coronary intervention.

METHODS AND RESULTS

Consecutive patients treated with primary percutaneous coronary intervention at our institution between January 2012 and December 2014 were studied. After excluding patients with prior coronary artery bypass surgery, 925 patients were included in the analysis. Patients were classified into 3 groups according to the as-treated revascularization strategy: culprit-vessel revascularization first, contralateral angiography first, or complete angiography first. Propensity score matching was used to minimize difference in clinical characteristics between groups. Predictors of culprit-vessel first revascularization were anterior/lateral infarct location and absence of diabetes mellitus. After propensity score matching, the median vascular access-to-balloon time was 4 to 6 minutes shorter with a culprit-vessel revascularization first strategy. This reduction in time to reperfusion increased the proportion of patients treated within recommended delays. However, there was no significant difference in 30-day clinical outcomes associated with these delays reduction.

CONCLUSIONS

Performing culprit-vessel primary percutaneous coronary intervention before contralateral or complete diagnostic angiography is associated with a statistically significant reduction in vascular access-to-balloon time, although the 4- to 6-minute difference is unlikely to be clinically relevant. This small but significant reduction could translate in an augmentation in the proportion of patients treated within recommended delays.

Coronary Atherosclerosis: Pathophysiologic Basis for Diagnosis and Management

Coronary atherosclerosis is a long lasting and continuously evolving disease with multiple clinical manifestations ranging from asymptomatic to stable angina, acute coronary syndrome (ACS), heart failure (HF) and sudden cardiac death (SCD). Genetic and environmental factors contribute to the development and progression of coronary atherosclerosis. In this review, current knowledge related to the diagnosis and management of coronary atherosclerosis based on pathophysiologic mechanisms will be discussed. In addition to providing state-of-the-art concepts related to coronary atherosclerosis, special consideration will be given on how to apply data from epidemiologic studies and randomized clinical trials to the individual patient. The greatest challenge for the clinician in the twenty-first century is not in absorbing the fast accumulating new knowledge, but rather in applying this knowledge to the individual patient.

Impact of preoperative dual antiplatelet therapy on bleeding complications in patients with acute coronary syndromes who undergo urgent coronary artery bypass grafting

BACKGROUND

A 5- to 7-day washout period before coronary artery bypass grafting (CABG) is recommended for patients who have recently received a thienopyridine derivative; however, data supporting this guideline recommendation are lacking in Japanese patients.

METHODS

Urgent isolated CABG was performed in 130 consecutive patients with acute coronary syndromes (ACS) (101 men; mean age, 69 years). Urgent CABG was defined as operation performed within 5 days after coronary angiography. All patients continued to receive aspirin 100mg/day. The subjects were retrospectively divided into 2 groups: 30 patients with preoperative thienopyridine (clopidogrel in 15 patients, ticlopidine in 15) exposure within 5 days [dual antiplatelet therapy (DAPT) group] and 100 patients without exposure [single antiplatelet therapy (SAPT) group].

RESULTS

Although the DAPT group had a higher proportion of patients who received perioperative platelet transfusions than the SAPT group (50% vs. 18%, p<0.001), intraoperative bleeding (median, 1100ml; interquartile range, 620-1440 vs. 920ml; 500-1100) and total drain output within 48h after surgery (577±262 vs. 543±277ml) were similar. CABG-related major bleeding, which was defined as type 4 or 5 bleeding according to the Bleeding Academic Research Consortium definitions, occurred in a significantly higher proportion of patients in the DAPT group than in the SAPT group (20% vs. 3%, p=0.005). This difference in major bleeding was driven mainly by the higher rate of transfusion of ≥5U red blood cells within a 48-h period in the DAPT group (13% vs. 1%, p=0.01). There was no significant difference in the 30-day composite endpoint including death, myocardial (re)infarction, ischemic stroke, and refractory angina between the DAPT group and SAPT group (17% vs. 19%).

CONCLUSIONS

Preoperative DAPT increases the risk of CABG-related major bleeding in Japanese patients with ACS undergoing urgent CABG.

Should dual antiplatelet therapy be used in patients following coronary artery bypass surgery? A meta-analysis of randomized controlled trials

BACKGROUND

We assessed the effectiveness of dual antiplatelet therapy (DAPT) post elective or urgent (i.e., post acute coronary syndrome [ACS]) coronary artery bypass graft surgery (CABG).

METHODS

We systematically searched MEDLINE, EMBASE, and the Cochrane Registry from inception to August 2015. Randomized controlled trials (RCTs) in adults undergoing CABG comparing either dual vs. single antiplatelet therapy or higher- vs. lower-intensity DAPT were identified.

RESULTS

Nine RCTs (n = 4,887) with up to 1y follow-up were included. Five RCTs enrolled patients post-elective CABG (n = 986). Two multi-centre RCTs enrolled ACS patients who subsequently underwent CABG (n = 2,155). These 7 RCTs compared clopidogrel plus aspirin to aspirin alone. Two other multi-centre RCTs reported on ACS patients who subsequently underwent CABG comparing higher intensity DAPT with either ticagrelor (n = 1,261) or prasugrel (n = 485) plus aspirin to clopidogrel plus aspirin. Post-operative anti-platelet therapy was started when chest tube bleeding was no longer significant, typically within 24-48 h. There were no differences in all-cause mortality in clopidogrel plus aspirin vs. aspirin RCTs; conversely, all-cause mortality was significantly lower in ticagrelor and prasugrel vs. clopidogrel RCTs (risk ratio[RR] 0.49, 95% confidence interval[CI] 0.33-0.71, p = 0.0002; 2 RCTs, n = 1695; I(2)  = 0%; interaction p < 0.01 compared to clopidogrel plus aspirin vs aspirin RCTs). There were no differences in myocardial infarctions, strokes, or composite outcomes. Overall, major bleeding was not significantly increased (RR 1.31, 95% CI 0.81-2.10, p = 0.27; 7 RCTs, n = 4500). There was heterogeneity (I(2)   = 42%) due almost entirely to higher bleeding reported for the prasugrel RCT which included mainly CABG-related major bleeding (RR 3.15, 95% CI 1.45-6.87, p = 0.004; 1 RCT, n = 437).

CONCLUSIONS

Most RCT data for DAPT post CABG is derived from subgroups of ACS patients in DAPT RCTs requiring CABG who resume DAPT post-operatively. Limited RCT data with heterogeneous trial designs suggest that higher intensity (prasugrel or ticagrelor) but not lower intensity (clopidogrel) DAPT is associated with an approximate 50% lower mortality in ACS patients who underwent CABG based on post-randomization subsets from single RCTs. Large prospective RCTs evaluating the use of DAPT post-CABG are warranted to provide more definitive guidance for clinicians.

Preoperative platelet aggregation predicts perioperative blood loss and rethoracotomy for bleeding in patients receiving dual antiplatelet treatment prior to coronary surgery

INTRODUCTION

Patients scheduled for coronary artery bypass graft surgery (CABG) are commonly treated with clopidogrel. We sought to assess the relation between preoperative platelet aggregation and bleeds in CABG patients on clopidogrel.

MATERIAL AND METHODS

In a case-control study, we compared 52 consecutive patients undergoing isolated CABG on aspirin and clopidogrel 75mg/d versus 50 controls on aspirin monotherapy. Platelet aggregation induced by 10μmol/l adenosine di-phosphate (ADP) in platelet-rich plasma was measured in subjects on clopidogrel within 5days prior to surgery. ADP-induced aggregation of ≥50% was used to define subjects with satisfactory inhibition of platelet reactivity.

RESULTS

In 29 patients with preoperative ADP-induced aggregation ≥50%, compared with 23 subjects with aggregation <50%, lower chest-tube drainage volumes (after 6h, p=0.002; and 12h, p=0.001) and fewer rethoracotomies were observed (p=0.03). The former group was characterized with lower transfusion rates of packed red blood cells (p=0.009), platelet concentrate (p=0.04) and fresh frozen plasma (p=0.001). Patients with ADP-induced aggregation ≥50% did not differ from untreated controls regarding the postoperative drainage, transfusions and rethoracotomy. The incidence of thromboembolic events and death during perioperative period were similar in all groups. Multivariate logistic regression identified ADP-induced aggregation <50% as the only independent predictor of rethoracotomy (OR=2.94 [1.12-7.75], p=0.029).

CONCLUSIONS

Patients on aspirin and clopidogrel <5days before CABG who had preoperative ADP-induced platelet aggregation ≥50% have bleeding risk similar to those receiving aspirin monotherapy. Reduced platelet reactivity to ADP can predict postoperative bleeding in CABG patients on dual antiplatelet therapy.

Predictive factors for bleeding-related re-exploration after cardiac surgery: A prospective cohort study

BACKGROUND

Bleeding-related re-exploration is a life-threatening complication after cardiac surgery. Nurses must be aware of important risk factors for this complication so that their assessment, monitoring and evaluation activities can be prioritized, focused and anticipated.

AIMS

To identify the predictive factors for bleeding-related re-exploration after cardiac surgery and to describe the sources of postoperative bleeding.

METHODS

This is a prospective cohort study at a tertiary cardiac school-hospital in São Paulo/SP, Brazil. Adult patients (n=323) submitted to surgical correction of acquired cardiac diseases were included. Potential risk factors for bleeding-related re-exploration within the 24 hours following admission to the intensive care unit were investigated in the patients' charts. A univariate analysis and a multiple analysis through logistic regression were conducted to identify the outcome predictors. The area under the receiver-operating characteristic curve was calculated as a measure of accuracy considering the cut-off points with the highest sensitivity and specificity.

RESULTS

The univariate factors significantly associated with bleeding-related re-exploration were a lower preoperative platelet count, a lower number of bypasses in coronary artery bypass surgery and postoperatively, a lower body temperature, infusion of lower intravenous volume, a higher positive end-expiratory pressure during mechanical ventilation and transfusion of blood products. The independent predictors of bleeding-related re-exploration included postoperative red blood cell transfusion, and transfusion of fresh frozen plasma, platelet or cryoprecipitate units. These predictors had a sensitivity of 87.5%, a specificity of 99.28% and an accuracy of 97.93%.

CONCLUSIONS

Blood product transfusion postoperatively is an independent predictor of bleeding-related re-exploration. Surgical errors prevailed as sources of bleeding.

Overview of the 2014 Food and Drug Administration Cardiovascular and Renal Drugs Advisory Committee meeting regarding cangrelor

Landmark clinical trials have established the benefit of P2Y12 inhibitors in the setting of acute coronary syndrome and percutaneous coronary intervention. On February 12, 2014, the Medicines Company (Sponsor) presented efficacy and safety data regarding cangrelor to the Food and Drug Administration (FDA) Cardiovascular and Renal Drugs Advisory Committee. The Sponsor sought approval for 2 indications: (1) in the setting of percutaneous coronary intervention for the reduction of thrombotic cardiovascular events (including stent thrombosis) in patients with coronary artery disease and (2) in the setting of bridging therapy in patients with acute coronary syndrome or with stents who are at increased risk for thrombotic events (such as stent thrombosis) when oral P2Y12 therapy is interrupted because of surgery. The following is a summary of the data presented to the FDA by the Sponsor, the FDA's clinical review of cangrelor.

Bleeding Outcomes Associated with Coronary Artery Bypass Graft Surgery and Recent Clopidogrel Exposure

<p><b>Background:</b> Guidelines recommend discontinuing clopidogrel for at least 5 days before elective coronary artery bypass graft surgery (CABG) to limit blood transfusions and for at least 24 hours before urgent CABG to reduce major bleeding complications. Studies have produced conflicting results regarding whether recent exposure to clopidogrel increases bleeding, the need for intraoperative and postoperative blood products, postoperative complications, and hospital length of stay. We evaluated the effect of clopidogrel exposure on major bleeding at our institution within 5 days of CABG.</p><p><b>Methods:</b> We conducted a retrospective review of patients who underwent CABG at a tertiary academic medical center. The primary outcome was major bleeding, defined as transfusion of 4 units of packed red blood cells (PRBCs) and/or a need for reexploration. Secondary outcomes included non-life-threatening bleeding, defined as transfusion of 2 units but <4 units of PRBCs; postoperative complications; hospital length of stay; readmission within 30 days of the procedure; and hospital mortality. Major bleeding events were analyzed with a logistic regression model that adjusted for covariates of bleeding risk factors.</p><p><b>Results:</b> Of the 715 patients we reviewed, 169 patients received clopidogrel within 5 days before CABG, and 546 patients did not. A significantly higher incidence of major bleeding was observed in the clopidogrel group compared with the group not exposed to clopidogrel (32% versus 17%, <i>P</i> = .002). After adjusting for covariates, patients exposed to clopidogrel had significantly higher odds of major bleeding (odds ratio, 2.1; 95% confidence interval, 1.3-3.4; <i>P</i> = .003). The groups were similar with respect to postoperative complications, except for infection. The clopidogrel-exposed group had a significantly higher rate of leg site infections (3% versus 0.2%, <i>P</i> = .003).</p><p><b>Conclusions:</b> Clopidogrel exposure within 5 days of CABG is associated with an increased risk of major bleeding.</p>

Point-of-care platelet function testing predicts bleeding in patients exposed to clopidogrel undergoing coronary artery bypass grafting: Verify pre-op TIMI 45--a pilot study

BACKGROUND

Guidelines recommend delaying coronary artery bypass grafting (CABG) for 5 days after discontinuing clopidogrel. However, platelet function may recover quicker in certain individuals.

HYPOTHESIS

We hypothesized that perioperative measurement of platelet function with a point-of-care P2Y12 inhibitor assay could predict bleeding during CABG in patients exposed to clopidogrel.

METHODS

Verify Pre-Op TIMI 45 was a prospective pilot study of 39 patients on clopidogrel who subsequently underwent CABG. Preoperative on-treatment platelet reactivity was assessed with VerifyNow P2Y12 Reaction Units (PRU), with higher PRU indicating more reactive platelets. Outcomes were stratified by PRU quartiles, as well as prespecified cutpoints for the lowest quartile (PRU 173), a cutpoint for major bleeding determined by the Youden index using receiver operator curve analysis (PRU 207), and clopidogrel resistance (PRU 230).

RESULTS

Patients in higher PRU quartiles experienced smaller decreases in hemoglobin and hematocrit (P < 0.05 for all comparisons), less major bleeding (P = 0.021), and less major or minor bleeding (P = 0.003). Patients above the PRU 207 and 230 cutpoints had less chest-tube output (P = 0.041 and P = 0.012, respectively), less major bleeding (P = 0.005 and P = 0.036, respectively), and less major or minor bleeding (P = 0.013 and P < 0.001, respectively). By receiver operator curve analysis, preoperative PRU ≤ 207 discriminated between patients with and without major bleeding during surgery (area under the curve: 0.76, 95% confidence interval: 0.59-0.94, P = 0.018).

CONCLUSIONS

In this pilot study, we found that point-of-care platelet function assessment could predict bleeding in patients recently exposed to clopidogrel undergoing CABG.

Thromboelastograph with Platelet Mapping(TM) predicts postoperative chest tube drainage in patients undergoing coronary artery bypass grafting

OBJECTIVE

The goal of this study was to evaluate the ability of Thromboelastograph with Platelet Mapping (TEG-PM(TM)) to predict postoperative bleeding tendency in patients with a history of recent anti-platelet therapy undergoing coronary artery bypass grafting (CABG).

DESIGN

A retrospective analysis. Association between predictor variables (MAADP [maximum amplitude produced by adenosine diphosphate], MAAA [maximum amplitude produced by arachidonic acid], percent of platelets inhibited by clopidogrel, percent of platelets inhibited by aspirin) and the outcomes as elevated chest tube drainage (CTD) and blood transfusion were investigated by logistic regression model. CTD was considered elevated if it was ≥ 600 mL within 12 hours after surgery.

SETTING

A university hospital.

PARTICIPANTS

Patients on antiplatelet therapy scheduled to undergo CABG that had TEG-PM(TM) done as a point-of-care test.

INTERVENTIONS

None.

RESULTS

A total of 78 patients had preoperative TEG-PM(TM) test and on-pump CABG surgeries performed on the same day. Among them, 20 patients (25.6%) had elevated CTD. Decreased MAADP (odds ratio [OR] 0.94), increased percent inhibition of platelets by clopidogrel (OR 1.03), and lower body mass index (BMI) (OR 0.78) were significantly associated with elevated CTD. The same parameters were also associated with platelets transfusion: MAADP (OR 0.94), percent of inhibition of platelets by clopidogrel (OR 1.03) and BMI (OR 0.77).

CONCLUSIONS

TEG-PM(TM) parameters and BMI are predictive of elevated CTD and platelets transfusion. A 1 mm decrease in MAADP increases the likelihood of elevated CTD and the likelihood of platelets transfusion by 6% whereas 1 unit decrease in BMI is associated with an increased likelihood of elevated CTD and platelets transfusion by 22% and 23% respectively.

Transfusion strategy: impact of haemodynamics and the challenge of haemodilution

Blood transfusion is associated with increased morbidity and mortality and numerous reports have emphasised the need for reduction. Following this there is increased attention to the concept of patient blood management. However, bleeding is relatively common following cardiac surgery and is further enhanced by the continued antiplatelet therapy policy. Another important issue is that cardiopulmonary bypass leads to haemodilution and a potential blood loss. The basic role of blood is oxygen transport to the organs. The determining factors of oxygen delivery are cardiac output, haemoglobin, and saturation. If oxygen delivery/consumption is out of balance, the compensation mechanisms are simple, as a decrease in one factor results in an increase in one or two other factors. Patients with coexisting cardiac diseases may be of particular risk, but studies indicate that patients with coexisting cardiac diseases tolerate moderate anaemia and may even benefit from a restrictive transfusion regimen. Further it has been shown that patients with reduced left ventricular function are able to compensate with increased cardiac output in response to bleeding and haemodilution if normovolaemia is maintained. In conclusion the evidence supports that each institution establishes its own patient blood management strategy to both conserve blood products and maximise outcome.

Adenosine diphosphate-induced single-platelet count aggregation and bleeding in clopidogrel-treated patients undergoing coronary artery bypass grafting

OBJECTIVES

To investigate the association between adenosine diphosphate (ADP)-induced platelet aggregation measured by single-platelet count testing and postoperative blood loss in clopidogrel-treated patients with acute coronary syndromes undergoing coronary artery bypass grafting (CABG).

DESIGN

Prospective observational study.

SETTING

Clinical study in one cardiac surgery center.

PARTICIPANTS

Eighty-eight patients treated with clopidogrel (300-600 mg loading dose followed by 75 mg daily) within 7 days before CABG.

INTERVENTIONS

Platelet function was assessed preoperatively by single-platelet count ADP-induced platelet aggregation. Postoperative blood loss and transfusion requirements were recorded.

MEASUREMENTS AND MAIN RESULTS

There was no significant association between ADP-induced platelet aggregation and blood loss 12 hours postoperatively (estimate -7.51; 95% confidence interval [CI]: -16.9-1.9; p = 0.12). ADP-induced platelet aggregation was associated significantly with the number of platelet concentrates administered within 24 hours after surgery (incidence rate ratio [IRR] 0.95; 95% CI: 0.92-0.98; p<0.01), but not to the number of packed red blood cells (IRR 0.98; 95% CI: 0.95-1.01; p = 0.14).

CONCLUSIONS

Preoperative ADP-induced platelet aggregation measured by single-platelet count testing in clopidogrel-treated patients with acute coronary syndromes undergoing CABG was not associated with postoperative blood loss or packed red blood cells transfused, but was associated significantly with number of platelet concentrates administered during the initial 24 postoperative hours.

Safety and efficacy of cangrelor, an intravenous, short-acting platelet inhibitor in patients requiring coronary artery bypass surgery

OBJECTIVE

Oral P2Y₁₂ platelet receptor inhibitors are a cornerstone of reducing complications in patients with acute coronary syndromes or coronary stents. Guidelines advocate discontinuing treatment with P2Y₁₂ platelet receptor inhibitors before surgery. Cangrelor, a short-acting, reversible, intravenously administered P2Y₁₂ platelet inhibitor is effective in achieving appropriate platelet inhibition in patients who are awaiting coronary artery bypass grafting (CABG) and require P2Y₁₂ inhibition. The objective of this study was to assess the effects of preoperative cangrelor on the incidence of perioperative complications, which are currently unknown.

METHODS

Patients (n = 210) requiring preoperative clinical administration of thienopyridine therapy were randomized in a multicenter, double-blinded study to receive cangrelor or placebo while awaiting CABG after discontinuation of the thienopyridine. Optimal platelet reactivity, which was defined as <240 P2Y₁₂ platelet reaction units, was measured with serial point-of-care testing (VerifyNow). Pre- and postoperative outcomes, bleeding values, and transfusion rates were compared. To quantify potential risk factors for bleeding, we developed a multivariate logistic model.

RESULTS

The differences between the groups in bleeding and perioperative transfusion rates were not significantly different. The rate of CABG-related bleeding was 11.8% (12/102) in cangrelor-treated patients and 10.4% (10/96) in the placebo group (P = .763). Transfusion rates for the groups were similar. Serious postoperative adverse events for the cangrelor and placebo groups were 7.8% (8/102) and 5.2% (5/96), respectively (P = .454).

CONCLUSIONS

Compared with placebo, bridging patients with cangrelor prior to CABG effectively maintains platelet inhibition without increasing post-CABG complications, including bleeding and the need for transfusions. These data suggest cangrelor treatment is a potential strategy for bridging patients requiring P2Y₁₂ receptor inhibition while they await surgery.

Platelet function testing to time surgery in patients on dual antiplatelet therapy?

In patients pretreated with P2Y12 receptor inhibitors who need to undergo non-emergent cardiac or major non-cardiac surgery, current guidelines of the European Society of Cardiology recommend postponing surgery for at least five days after last intake of clopidogrel or ticagrelor, and for seven days after last intake of prasugrel, unless there is high risk of ischemic events. However, a fixed five to seven days preoperative waiting period may be challenged, in the presence of inter-individual variability in on-treatment platelet reactivity. Therefore, Society of Thoracic Surgeons guidelines suggest to base decisions about a surgical delay on platelet function although both, the optimal platelet function assay and a bleeding cutoff have not yet been defined by large scale multicenter trials. This review aims to provide an overview on current knowledge of P2Y12 receptor induced platelet inhibition and surgery related bleeding and the potential role of platelet function analysis to time surgery.

Optimal anticoagulation during off pump coronary artery bypass in patients recently exposed to clopidogrel

PURPOSE

The aim of this study was to find an optimal range of activated clotting time (ACT) during off-pump coronary artery bypass surgery (OPCAB) yielding ischemic protection without the risk of hemorrhagic complications in patients with recent exposure to dual antiplatelet therapy.

MATERIALS AND METHODS

Three hundred and five patients who received aspirin and clopidogrel within 7 days of isolated multi-vessel OPCAB were retrospectively studied. Combined hemorrhagic and ischemic outcome was defined as the occurrence of 1 of the following: significant perioperative bleeding (>30% of estimated blood volume), transfusion of packed red blood cell (pRBC) ≥ 2 U, or myocardial infarction (MI). This was compared in relation to the tertile distribution of the time-weighted average ACT-212-291 sec (first tertile), 292-334 sec (second tertile), 335-485 sec (third tertile).

RESULTS

The amount of perioperative blood loss was 937 ± 313 mL, 1014 ± 340 mL, and 1076 ± 383 mL, respectively (p=0.022). Significantly more patients in the third tertile developed MI (4%, 4%, and 12%, respectively, p=0.034). The incidence of significant perioperative blood loss and transfusion of pRBC ≥ 2 U were lower in the first tertile than those of other tertiles without statistical significance. In the multivariate analysis, the first tertile was associated with a 52% risk reduction of combined hemorrhagic and ischemic outcomes (95% confidence interval: 0.25-0.92, p= 0.027).

CONCLUSION

A lower degree of anticoagulation with a reduced initial heparin loading dose should be carefully considered for patients undergoing OPCAB who have recently been exposed to clopidogrel.

Thienopyridines resistance and recovery of platelet function after discontinuation of thienopyridines in cardiac surgery patients

OBJECTIVES

Patients who undergo cardiac operations under the effects of thienopyridines have a greater risk of major postoperative bleeding, transfusions and surgical revision due to bleeding. Discontinuation of thienopyridine is suggested but an adequate recovery period following discontinuation is still under debate, with opinions ranging from 3 to 7 days. The aim of this study was to assess the rate of recovery of thienopyridine-resistant patients and the time taken for resumption of platelet function after discontinuation of thienopyridine, in the setting of patients scheduled for cardiac operations.

METHODS

This was a retrospective study, based on 344 patients screened for platelet aggregation before cardiac operations. All the patients received thienopyridines within 7 days prior to the test. Multiple electrode aggregometry adenosine diphosphate test was used to assess platelet aggregation before the operation.

RESULTS

Thienopyridine resistance rate was 28%. Patients receiving clopidogrel had a significantly higher rate (32%) of resistance, compared with those receiving ticlopidine (14%) and thienopyridine resistance was significantly associated with platelet count (P = 0.006). The time taken to recover platelet function after thienopyridine discontinuation was variable between individuals; the only factor associated with a faster recovery time was the serum bilirubin value (P = 0.002). Platelet aggregation values high enough to avoid major bleeding were reached 3 days after discontinuation (95% confidence interval: 2-4 days); however, a complete recovery of platelet function was reached only after 8 days (95% confidence interval: 7-9 days).

CONCLUSIONS

Patient-specific factors determine the effectiveness of thienopyridine treatment and platelet function recovery rate. Among these, platelet count (for thienopyridine resistance) and serum bilirubin values (for platelet function recovery rate) should be considered.