Hrvoje Gasparovic

Changes in IgG and total plasma protein glycomes in acute systemic inflammation

Recovery after cardiac surgery is a complex process that has to compensate for both individual variability and extensive tissue damage in the context of systemic inflammation. Protein glycosylation is essential in many steps of the inflammatory cascade, but due to technological limitations the role of individual variation in glycosylation in systemic inflammation has not been addressed until now. We analysed composition of the total plasma and IgG N-glycomes in 107 patients undergoing cardiac surgery. In nearly all individuals plasma N-glycome underwent the same pattern of changes in the first 72u2005h, revealing a general mechanism of glycosylation changes. To the contrary, changes in the IgG glycome were very individualized. Bi-clustering analysis revealed the existence of four distinct patterns of changes. One of them, characterized by a rapid increase in galactosylated glycoforms, was associated with nearly double mortality risk measured by EuroSCORE II. Our results indicate that individual variation in IgG glycosylation changes during acute systemic inflammation associates with increased mortality risk and indicates new avenues for the development of personalized diagnostic and therapeutic approach.

Bleeding risk assessment using multiple electrode aggregometry in patients following coronary artery bypass surgery.

Individual variability in the response to antiplatelet therapy (APT), frequently administered preoperatively, has been established by various platelet function assays and could reflect bleeding tendency after coronary artery bypass surgery (CABG). Our hypothesis is that multiple electrode whole-blood aggregometry (MEA) can identify patients at risk for excessive bleeding. We enrolled 211 patients (155 male and 56 female) undergoing isolated CABG in a prospective observational study. Patients were divided into four groups with respect to their preoperative APT management. MEA, using the ASPI and the ADP test, was performed prior to surgery. The primary endpoint was chest tube output (CTO) and the secondary endpoint was perioperative packed red blood cell concentrate (PRBC) administration. Patients were characterized as bleeders if their 24xa0h CTO exceeded the 75th percentile of distribution. 24xa0h CTO value of 11.33xa0ml/kg presented 75th percentile of distribution, thus cut-off value for “bleeder category”. The proportion of patients characterized as bleeders was significantly different among the groups in regard to preoperative APT (pxa0=xa00.039). Significant differences in both ASPI (pxa0<xa00.001) and ADP (pxa0=xa00.038) tests were observed between different preoperative APT groups. Significant correlations between the ASPI test (rxa0=xa0−0.170, pxa0=xa00.014) and ADP test (rxa0=xa0−0.206, pxa0=xa00.003) with 24xa0h CTO were found. The receiver operating curve revealed an ASPI test value of <20 area under curve (AUC) units (AUC 0.603, pxa0=xa00.023) and an ADP test <73 AUC (AUC 0.611, pxa0=xa00.009) as a “bleeder” determinant. The proportion of patients transfused with PRBC did not significantly differ among the groups in regard to preoperative APT (pxa0=xa00.636). Comparison of the ASPI test values between patients with respect to PRBC administration revealed lower values in the ASPI test in a group of patients transfused with PRBC (mean, 27.88 vs. 40.32 AUC, pxa0=xa00.002). Our study showed that MEA is a useful method of predicting CABG patients with excessive postoperative bleeding.

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 24xa0h 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 1xa0year 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, pxa0=xa00.004) and ADP test values (median, 22 vs. 41 AUC, pxa0=xa00.002) as well as TEM values expressed in maximum clot firmness after 30xa0min (MCF 30) for ExTEM (53 vs. 56xa0mm, pxa0=xa00.005), HepTEM (48 vs. 52xa0mm, pxa0=xa00.003) and FibTEM (8 vs. 11xa0mm, pxa0<xa00.001) test. 24xa0h CTO inversely correlated with both the MEA (ASPI test: rxa0=xa0−0.236, pxa0=xa00.004; ADP test: rxa0=xa0−0.299, pxa0<xa00.001), and TEM MCF 30 (ExTEM: rxa0=xa0−0.295, pxa0<xa00.001; HepTEM: −0.329, pxa0<xa00.001; FibTEM: −0.377, pxa0<xa00.001) 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.

Assessment of platelet function by whole blood impedance aggregometry in coronary artery bypass grafting patients on acetylsalicylic acid treatment may prompt a switch to dual antiplatelet therapy

Residual platelet reactivity (RPR) following coronary artery bypass grafting (CABG) might be related to thrombotic complications and major ischemic cardiac events. The aim of this study was to evaluate the changes in platelet reactivity monitored pre- and postoperatively using multiple-electrode aggregometry (MEA) and to propose an alternative therapeutic approach in a subgroup of patients with postoperative RPR. Ninety-nine patients undergoing elective CABG were enrolled in the study, of whom 41 (41.4%) were diabetic. Preoperatively, all patients received 100 mg acetylsalicylic acid (ASA), with 47 of 99 (47.4%) patients receiving an additional 75 mg clopidogrel (CLO). The blood samples were drawn the day before surgery, and on the first and 4th postoperative day. Platelet count and fibrinogen level were documented, as well as type and daily dose of antiplatelet therapy (APT) received pre- and postoperatively. Multiple-electrode aggregometry using tests based on arachidonic acid (ASPI test) and adenosine diphosphate (ADP test) was performed on the day before and 4 days after surgery. Preoperatively, we detected 31 of 99 (31.3%) patients with RPR (ASPI > 30 AUC). Platelet count correlated with both the ASPI (P = 0.03) and ADP (0.002) tests. Fibrinogen correlated with ADP test values (P < 0.001) and was found to have a higher level in the diabetic subgroup (P = 0.01). In comparison with preoperative results, we detected higher values of ASPI test postoperatively (P = 0.04), with 46 of 99 (46.5%) patients having RPR despite a higher dose of 300 mg ASA being administered. Postoperatively, diabetic patients had higher ASPI test values (P = 0.01), and a higher proportion of patients with RPR compared with the nondiabetic subgroup (58.5 vs 38%, P = 0.04). The subgroup of patients with detected ASPI >30 AUC at the 4th postoperative day consequently received as a part of our clinical routine an additional 75 mg CLO per day, in terms of platelet inhibition optimization. Multiple-electrode aggregometry can recognize patients with RPR during both the pre- and post-CABG period. Postoperatively administered ASA (300 mg) did not sufficiently inhibit platelet aggregation in 46.5% of post-CABG patients. In this group of patients a switch to dual APT should be considered.

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.

Atrial apoptosis and fibrosis adversely affect atrial conduit, reservoir and contractile functions †

OBJECTIVESnChronic atrial volume overload and atrial fibrillation (AF) induce structural changes within atrial myocardium. The aim of this study was to evaluate the effect of adverse cellular remodelling on echocardiographic strain rate (SR) deformation indices of atrial contractile, conduit and reservoir functions.nnnMETHODSnForty-four consecutive patients with organic mitral regurgitation were analysed. Twenty-eight patients had long-standing persistent AF (AF group), while 16 were in normal sinus rhythm (NSR group). Left atrial (LA) samples were harvested from all the patients for histological analysis. Postoperative echocardiographic data acquisition was performed exclusively during organized atrial electrical activity in order to assess the contractile reserve of patients from both groups.nnnRESULTSnFibrotic atria had inferior conduit (SR-E: r = -0.36, P = 0.017), reservoir (SR-S: r = -0.31, P = 0.041) and contractile functions (SR-A: r = -0.33, P = 0.027). Analogously, atria with greater apoptotic burdens showed a negative correlation with multiple indices of left atrial functions (SR-E: r = -0.38, P = 0.010; SR-S: r = -0.33, P = 0.028; SR-A: r = -0.28, P = 0.067). The efficiency of atrial contractility was significantly reduced among AF-group patients after conversion to sinus rhythm, when compared with patients in the NSR group (LA active emptying fraction: 20 ± 12 vs 30 ± 10%, P = 0.004; SR-A: 1.1 ± 1.0 vs 2.8 ± 1.9 s(-1), P < 0.001). Superior strain-rate indices of atrial conduit and reservoir functions were noted in the NSR group (SR-E: 3.5 ± 2.3 vs 1.3 ± 1.0 s(-1), P < 0.001; LA expansion index: 86 ± 31 vs 60 ± 42%, P = 0.004). Fibrosis was evident in 7.2 [3.3;9.4]% of the LA tissue sample in the AF group, while it accounted for 3.4 [1.2;8.1]% of atrial tissue in the NSR group (P = 0.054). Apoptosis was documented in 13 (46%) patients in the AF group, whereas none of the patients in the NSR group exhibited signs of programmed cell death (P = 0.001). Myocyte degeneration was more prevalent in the AF group (odds ratio: 7.0, 95% confidence interval: 1.3-36.7, P = 0.021). Age showed a positive correlation with worsening degrees of atrial fibrosis and apoptosis (r = 0.41, P = 0.006; r = 0.49, P = 0.001, respectively). Multiple regression analysis identified SR-S (β = -1.263, P = 0.036) and age (β = 0.144, P = 0.057) as independent predictors of fibrosis. Independent determinants of apoptosis were preoperative AF (β = 4.539, P = 0.007), age (β = 0.188, P = 0.009) and SR-S (β = -1.780, P = 0.002).nnnCONCLUSIONSnAtria exhibiting greater fibrotic and apoptotic burdens had impaired conduit, reservoir and contractile function, as evaluated by deformation imaging. Among patients with chronic LA volume overload, exposure to long-standing persistent AF induced more pronounced degrees of adverse atrial cellular remodelling. Strain-rate descriptors of atrial reservoir function harboured potential to predict atrial fibrosis and apoptosis.

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

B ackgroundCoronary 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.MethodsPatients 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.DiscussionThis 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).

Aortic Root Vasculitis Associated With Cogan's Syndrome

Cogans syndrome is characterized by nonsyphilitic interstitial keratitis and an audiovestibular disorder resembling Meniere disease. We report a patient with progressive congestive heart failure due to massive aortic and mitral insufficiency coupled with aortitis leading to an ascending aortic aneurysm. The patient underwent successful aortic root replacement and mitral valve repair.

Increased plasma N-glycome complexity is associated with higher risk of type 2 diabetes

Aims/hypothesisBetter understanding of type 2 diabetes and its prevention is a pressing need. Changes in human plasma N-glycome are associated with many diseases and represent promising diagnostic and prognostic biomarkers. Variations in glucose metabolism directly affect glycosylation through the hexosamine pathway but studies of plasma glycome in type 2 diabetes are scarce. The aim of this study was to determine whether plasma protein N-glycome is changed in individuals who are at greater risk of developing type 2 diabetes.MethodsUsing a chromatographic approach, we analysed N-linked glycans from plasma proteins in two populations comprising individuals with registered hyperglycaemia during critical illness (increased risk for development of type 2 diabetes) and individuals who stayed normoglycaemic during the same condition: AcuteInflammation (59 cases vs 49 controls) and AcuteInflammation Replication (52 cases vs 14 controls) populations. N-glycome was also studied in individuals from FinRisk (37 incident cases of type 2 diabetes collected at baseline vs 37 controls), Orkney Complex Disease Study (ORCADES; 94 individuals with HbA1c >xa06.5% [47.5xa0mmol/mol] vs 658 controls) and Southall and Brent Revisited (SABRE) cohort studies (307 individuals with HbA1c >xa06.5% [47.5xa0mmol/mol] vs 307 controls).ResultsIndividuals with increased risk for diabetes type 2 development (AcuteInflammation and AcuteInflammation Replication populations), incident cases of type 2 diabetes collected at baseline (FinRisk population) and individuals with elevated HbA1c (ORCADES and SABRE populations) all presented with increased branching, galactosylation and sialylation of plasma protein N-glycans and these changes were of similar magnitude.Conclusions/interpretationIncreased complexity of plasma N-glycan structures is associated with higher risk of developing type 2 diabetes and poorer regulation of blood glucose levels. Although further research is needed, this finding could offer a potential new approach for improvement in prevention of diabetes and its complications.

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)

BackgroundExcessive 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.MethodsWe 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 15xa0min 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.ResultsTotal amount of CTO value of 1507,50xa0mL 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 38xa0mm, InTEM A 20 value of 49xa0mm and InTEM A 30 value of 51xa0mm 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%, pu2009<u20090.001), fibrinogen concentrate (21.6% vs. 2.7%, pu2009=u20090.001) and platelet concentrate (13.5% vs. 0.9%, pu2009=u20090.004).ConclusionOur 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.