The Association between Glycosylated Hemoglobin Level and Platelets Reactivity in Patients with Diabetes Mellitus Undergoing Elective Coronary Artery Bypass Grafting.

BACKGROUND: Diabetic patients tend to have increased platelet reactivity after coronary artery bypass grafting (CABG). The aim of this study was to determine the association between hemoglobin A1c (HbA1c) values and platelet reactivity and to evaluate the consequent impact on clinical outcomes in patients undergoing CABG. METHODS: This prospective observational trial consecutively enrolled 225 diabetic patients undergoing CABG, between February 2014 and October 2018. HbA1c levels and platelet function (multiple electrode aggregometry [MEA]) were analyzed the day before surgery and on postoperative day 4 (POD 4). Patients were divided into two groups according to the HbA1c value: HBA1c < 7% and HbA1c ≥ 7%. RESULTS: Significantly higher postoperative ASPI (platelet function test based on arachidonic acid) and ADP (platelet function test based on adenosine diphosphate) test values were observed at POD 4 compared with preoperative values (ASPI test: p < 0.001; ADP test: p < 0.001). The prevalence of preoperative aspirin resistance (AR) was 46.4% relative to 57.2% after surgery showing consistent increase in postoperative AR by approximately 10%. In addition, the prevalence of AR in the HbA1c < 7% group was higher by 10% compared with the HbA1c ≥ 7% group, both before and after surgery. We did not demonstrate differences in clinical outcomes between the HbA1c groups. CONCLUSION: Perioperative assessment of platelet reactivity in diabetic patients detects those with AR who may be at increased risk of adverse ischemic events. A personalized approach guided by MEA and administration of early and more potent antiaggregation therapy after CABG can be beneficial in this group of patients.

De Novo Aortic Regurgitation After Continuous-Flow Left Ventricular Assist Device Implantation.

Continuous-flow left ventricular assist devices (cf-LVAD) play an important role in the management of patients with advanced heart failure. De novo aortic regurgitation after cf-LVAD implantation may adversely impact device performance. We performed a systematic search of PubMed, SCOPUS, and Cochrane Library for articles reporting on the incidence and predictors of de novo aortic regurgitation among cf-LVAD recipients. Eight studies totaling 548 patients were identified in the meta-analysis. The pooled incidence of de novo AR across the analyzed studies was 37%. Factors influencing its development and progression are older age, persistent aortic valve closure, being female, and duration of cf-LVAD support.

Postoperative Atrial Fibrillation Is Associated With High On-Aspirin Platelet Reactivity.

BACKGROUND: Atrial fibrillation (AF) contributes to a prothrombotic state through platelet activation. It is unclear whether increased platelet aggregability in patients with AF is caused by the underlying cardiovascular condition rather than the arrhythmia per se. We investigated the effect of postoperative atrial fibrillation (POAF) on platelet reactivity after coronary artery bypass grafting (CABG). METHODS: This study is a post hoc analysis from a randomized controlled trial (ClinicalTrials.gov: NCT01159639) based on patients undergoing elective primary CABG. Patients were dichotomized according to POAF. Postoperative platelet function testing with arachidonic acid as the platelet agonist (ASPI test) was used to define high on-aspirin platelet reactivity (HAPR). ΔASPI presented the difference between pre- and postoperative ASPI test values. To account for the isolated effect of POAF on platelet reactivity, a propensity score analysis was applied. RESULTS: Overall incidence of POAF was 23% (92 of 398 patients). HAPR was detected in 54% (214 of 398) of patients. HAPR was more prevalent among patients with POAF when compared with patients without POAF (64.1% versus 50.7%; odds ratio [OR], 1.74; 95% confidence interval [CI], 1.08-2.82; p = 0.023). The propensity score model produced a subcohort of patients that was well balanced for comorbidities. When compared with the matched group without POAF, the POAF group maintained its prevalence for HAPR (64.1% versus 45.7%; OR, 2.13; 95% CI, 1.18-3.85; p = 0.012) and had greater ΔASPI values (15.0 [IQR, 0.0-36.0] vs 8.0 [IQR, -5.5-19.5]; p = 0.030). CONCLUSIONS: The main finding of our study indicates there is added platelet activation in patients with POAF after CABG before and after controlling for pathologic conditions through propensity matching. The present study does not prove a causal association between POAF and HAPR.

Impact of aspirin resistance on outcomes among patients following coronary artery bypass grafting: exploratory analysis from randomized controlled trial (NCT01159639).

Individual variability in the response to aspirin, has been established by various platelet function assays, however, the clinical relevance of aspirin resistance (AR) in patients undergoing coronary artery bypass grafting (CABG) has to be evaluated. Our working group conducted a randomized controlled trial (NCT01159639) with the aim to assess impact of dual antiplatelet therapy (APT) on outcomes among patients with AR following CABG. Patients that were aspirin resistant on fourth postoperative day (POD 4) were randomly assigned to receive either dual APT with clopidogrel (75 mg) plus aspirin (300 mg)-intervention arm or monotherapy with aspirin (300 mg)-control arm. This exploratory analysis compares clinical outcomes between aspirin resistant patients allocated to control arm and patients that have had adequate platelet inhibitory response to aspirin at POD 4. Both groups were treated with 300 mg of aspirin per day following surgery. We sought to evaluate the impact of early postoperative AR on outcomes among patients following CABG. Exploratory analysis included a total number of 325 patients. Of those, 215 patients with adequate response to aspirin and 110 patients with AR allocated to aspirin monotherapy following randomization protocol. The primary efficacy end point (MACCEs-major adverse cardiac and cardiovascular events) occurred in 10 and 6 % of patients with AR and with adequate aspirin response, respectively (p = 0.27). Non-significant differences were observed in bleeding events occurrence. Subgroup analysis of the primary end point revealed that aspirin resistant patients with BMI > 30 kg/m(2) tend to have a higher occurrence of MACCEs 18 versus 5 % (relative risk 0.44 [95 % CI 0.16-1.16]; p = 0.05). This exploratory analysis did not reveal significant impact of aspirin resistance on outcomes among patients undergoing CABG. Further, sufficiently powered studies are needed in order to evaluate clinical relevance of AR in patients undergoing CABG.

Activated coagulation time vs. intrinsically activated modified rotational thromboelastometry in assessment of hemostatic disturbances and blood loss after protamine administration in elective cardiac surgery: analysis from the clinical trial (NCT01281397).

BACKGROUND: Excessive bleeding after cardiopulmonary bypass (CPB) is risk factor for adverse outcomes after elective cardiac surgery (ECS). Although many different point-of-care devices to diagnose hemostatic disturbances after CPB are available, the best test is still unclear. The study aim was to compare the accuracy of hemostatic disorder detection between two point-of-care devices. METHODS: We enrolled 148 patients (105 male and 43 female) undergoing ECS in a prospective observational study. Rotational thromboelastometry (TEM, with InTEM test), and Activated coagulation time (ACT) measurement were performed 15 min after protamine administration. The cohort group was divided into two subgroups according to occurrence of excessive postoperative bleeding. Endpoints were defined in two ways: as total amount of chest tube output (CTO) and blood product transfusion requirements. RESULTS: Total amount of CTO value of 1507,50 mL presented 75th percentile of distribution, thus cut-off value for bleeder category. InTEM parameters, but not ACT, correlated significantly with CTO. InTEM parameters with the strongest correlation to CTO were tested for accuracy in predicting excessive postoperative bleeding using ROC analysis. InTEM A 10 value of 38 mm, InTEM A 20 value of 49 mm and InTEM A 30 value of 51 mm delineated bleeding tendency. Patients with total amount of CTO exceeding 75th percentile were more frequently transfused with fresh frozen plasma (51.4% vs. 9.9%, p < 0.001), fibrinogen concentrate (21.6% vs. 2.7%, p = 0.001) and platelet concentrate (13.5% vs. 0.9%, p = 0.004). CONCLUSION: Our study showed that InTEM test, but not ACT is useful in prediction of bleeding tendency after protamine administration following weaning from CPB. InTEM test could be used as a first line test in screening of possible hemostatic disorder following protamine administration.

Impact of dual antiplatelet therapy on outcomes among aspirin-resistant patients following coronary artery bypass grafting.

Coronary artery bypass grafting is pivotal in the contemporary management of complex coronary artery disease. Interpatient variability to antiplatelet agents, however, harbors the potential to compromise the revascularization benefit by increasing the incidence of adverse events. This study was designed to define the impact of dual antiplatelet therapy (dAPT) on clinical outcomes among aspirin-resistant patients who underwent coronary artery surgery. We randomly assigned 219 aspirin-resistant patients according to multiple electrode aggregometry to receive clopidogrel (75 mg) plus aspirin (300 mg) or aspirin-monotherapy (300 mg). The primary end point was a composite outcome of all-cause death, nonfatal myocardial infarction, stroke, or cardiovascular hospitalization assessed at 6 months postoperatively. The primary end point occurred in 6% of patients assigned to dAPT and 10% of patients randomized to aspirin-monotherapy (relative risk 0.61, 95% confidence interval 0.25 to 1.51, p = 0.33). No significant treatment effect was noted in the occurrence of the safety end point. The total incidence of bleeding events was 25% and 19% in the dAPT and aspirin-monotherapy groups, respectively (relative risk 1.34, 95% confidence interval 0.80 to 2.23, p = 0.33). In the subgroup analysis, dAPT led to lower rates of adverse events in patients with a body mass index >30 kg/m(2) (0% vs 18%, p <0.01) and those <65 years (0% vs 10%, p = 0.02). In conclusion, the addition of clopidogrel in patients found to be aspirin resistant after coronary artery bypass grafting did not reduce the incidence of adverse events, nor did it increase the number of recorded bleeding events. dAPT did, however, lower the incidence of the primary end point in obese patients and those <65 years.

Pretransplant and perioperative predictors of early heart transplantation outcomes.

Aim. To identify predictors of 3-month mortality after heart transplantation in a Croatian academic center. Methods. A retrospective review of institutional database identified 117 heart transplantations from January 2008 to July 2014. Two children <14 years were excluded from the study. The remaining 115 patients were dichotomized into survivors and non-survivors adjudicated at 3-months postoperatively, and their demographic, clinical, and longitudinal hemodynamic data were analyzed. Results. 3-month survival after heart transplantation was 86%. Non-survivors were older (59±8 vs 50±14 years, P=0.009), more likely to have previous cardiac surgery (44% vs 19%; odds ratio [OR] 3.28, 95% confidence interval [CI] 1.08-9.90; P=0.029), lower body mass index (BMI) (25±4 vs 28±2 kg/m(2), P=0.001), and be diabetics (44% vs 23%; OR 2.57, 95% CI 0.86-7.66; P=0.083). Creatinine clearance was marginally superior among survivors (59=19 vs 48 ± 20 mL/min, P=0.059). Donor age and sex did not affect outcomes. Non-survivors were more likely to have had ischemic cardiomyopathy (69% vs 32%, P=0.010). Postoperative utilization of epinephrine as a second line inotropic agent was a strong predictor of mortality (63% vs 7%; OR 21.91; 95% CI 6.15-78.06; P<0.001). Serum lactate concentrations were consistently higher among non-survivors, with the difference being most pronounced 2 hours after cardiopulmonary bypass (9.8±3.5 vs 5.2±3.2 mmol/L, P<0.001). The donor hearts exhibited inferior early hemodynamics in non-survivors (cardiac index 3.0±1.0 vs 4.0±1.1 L/min/m(2), P=0.001), stroke volume (49±24 vs 59±19 mL, P=0.063), and left and right ventricular stroke work indices (18±8 vs 30±11 g/beat/m(2), P<0.001 and 5±3 vs 7±4 g/beat/m(2), P=0.060, respectively). Non-survivors were more likely to require postoperative re-sternotomy (50% vs 12%; OR 7.25, 95% CI 2.29-22.92; P<0.001), renal replacement therapy (RRT) (69% vs 9%; OR 22.00, 95% CI 6.24-77.54; P<0.001), and mechanical circulatory assistance (MCS) (44% vs 5%; OR 14.62, 95% CI 3.84-55.62; P<0.001). Binary logistic regression revealed recipient age (P=0.024), serum lactates 2 hours after CPB (P=0.007), and epinephrine use on postoperative day 1 (P=0.007) to be independently associated with 3-month mortality. Conclusion. Pretransplant predictors of adverse outcome after heart transplantation were recipient age, lower BMI, ischemic cardiomyopathy, reoperation and diabetes. Postoperative predictors of mortality were inferior donor heart hemodynamics, epinephrine use, and serum lactate concentrations. Non-survivors were more likely to require re-sternotomy, MCS, and RRT.

Definition of acetylsalicylic acid resistance using whole blood impedance aggregometry in patients undergoing coronary artery surgery.

A beneficial effect of acetylsalicylic acid (ASA) on vein graft patency has been described, but some patients experience adverse cardiac events despite appropriate ASA treatment. Study aim was to define ASA resistance using Multiple electrode aggregometry (MEA) preoperatively in group of patients undergoing coronary artery bypass grafting (CABG). Prospective observational trial at University Hospital Center Zagreb enrolled 131 patients scheduled for CABG, and divided them into 4 groups with respect to preoperative antiplatelet therapy (APT). Group 1 received 100 mg ASA per day, Group 2 100 mg ASA + 75 mg clopidogrel per day, Group 3 75 mg clopidogrel per day, and Group 4 did not receive any APT. MEA with ASPI test (sensitive to ASA) and ADP test (sensitive to clopidogrel) was performed prior to surgery. In Group 1, patients were characterized as ASA resistant if their ASPI test value exceeded the 75th percentile distribution. Study enrolled 131 patients. Significant differences both in the ASPI (p < 0.001) and the ADP test (p = 0.038) were observed between patients in different APT groups. In Group (1) ASPI test value of 30 AUC presented 75th percentile of distribution, thus indicating ASA resistance. Group 2 patients had slightly lower ADP test values, but no significant difference occurred (mean 60.05 vs. 63.32 AUC, p = 0.469). In Group 1 and 2, significant correlations between the ADP test and both, platelet count (r = 0.347, p < 0.001) and fibrinogen level (r = 0.364, p < 0.001) were observed. Association between low response to ASA and post-CABG major adverse ischemic events risk increase has been described thus indicating need for ASA resistant patients detection. In patients with preoperative ASPI test exceeding 30 AUC postoperative, ASA dose adjustment or clopidogrel addition according to MEA results should be considered.

Bleeding risk assessment using whole blood impedance aggregometry and rotational thromboelastometry in patients following cardiac surgery.

Excessive bleeding after cardiopulmonary bypass (CPB) is risk factor for adverse outcomes after elective cardiac surgery (ECS). Differentiating between patients who bleed due to surgical issues and those whose excessive chest tube output (CTO) is due to coagulopathy, remains challenging. Bedside suitable tests to identify hemostatic disturbances and predict excessive bleeding are desirable. The study sought to evaluate prediction of excessive bleeding after ECS using two bedside suitable devices for platelet function and viscoelastic blood clot properties assessment. We enrolled 148 patients (105 male and 43 female) undergoing ECS in a prospective observational study. Patients were characterized as bleeders if their 24 h CTO exceeded the 75th percentile of distribution. Multiple electrode aggregometry (MEA, with ASPI, ADP and the TRAP test) and rotational thromboelastometry (TEM, with ExTEM, HepTEM and FibTEM test), were performed at three time points: preoperatively (T1), during CPB (T2), and after protamine administration (T3). The primary endpoint was CTO and the secondary endpoint was administration of blood products, 30-day and 1 year mortality. The best predictors of increased bleeding tendency were the tests performed after protamine administration (T3). At T3, patients characterized as bleeders had significantly lower MEA ASPI (median, 14 vs. 27 AUC, p = 0.004) and ADP test values (median, 22 vs. 41 AUC, p = 0.002) as well as TEM values expressed in maximum clot firmness after 30 min (MCF 30) for ExTEM (53 vs. 56 mm, p = 0.005), HepTEM (48 vs. 52 mm, p = 0.003) and FibTEM (8 vs. 11 mm, p < 0.001) test. 24 h CTO inversely correlated with both the MEA (ASPI test: r = -0.236, p = 0.004; ADP test: r = -0.299, p < 0.001), and TEM MCF 30 (ExTEM: r = -0.295, p < 0.001; HepTEM: -0.329, p < 0.001; FibTEM: -0.377, p < 0.001) test values. Our study showed that MEA and TEM are useful methods for prediction of excessive bleeding after ECS. In order to prevent excessive postoperative CTO, hemostatic interventions with timely and targeted blood component therapy according to MEA and TEM results should be considered.

Dual antiplatelet therapy in patients with aspirin resistance following coronary artery bypass grafting: study protocol for a randomized controlled trial [NCT01159639].

BACKGROUND: Coronary artery disease remains the dominant cause of mortality in developed countries. While platelets have been recognized to play a pivotal role in atherothrombosis, the ideal antiplatelet regime after coronary artery surgery remains elusive. The evolution of CABG has presently moved beyond technical improvements to involve modulation of pharmacologic management designed to improve patient outcomes. The aim of this trial will be to test the hypothesis that the addition of clopidogrel to patients with documented postoperative aspirin resistance will reduce the incidence of major cardiovascular events. METHODS: Patients scheduled for isolated coronary artery surgery will be eligible for the study. Patients in whom postoperative multiple electrode aggregometry documents aspirin resistance will be randomized into two groups. The control group will receive 300 mg of aspirin. The dual antiplatelet group will receive 75 mg of clopidogrel in addition to 300 mg of aspirin. Patients will be followed for 6 months. Major adverse cardiac and cerebrovascular events (death from any cause, myocardial infarction, stroke, hospitalization due to cardiovascular pathology) as well as bleeding events will be recorded. DISCUSSION: This will be the first trial that will specifically address the issue of dual antiplatelet therapy in patients undergoing coronary artery surgery who have been found to be aspirin resistant. In the event that the addition of clopidogrel proves to be beneficial in this subset of surgical patients, this study could significantly impact their future antiplatelet management. This randomized controlled trial has been registered at the ClinicalTrials.gov website (Identifier NCT01159639).