Tomislav Kopjar

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.

NT-pro-BNP, but not C-reactive protein, is predictive of atrial fibrillation in patients undergoing coronary artery bypass surgery

OBJECTIVE Atrial fibrillation (AF) remains the most commonly observed complication following myocardial revascularisation surgery. We aimed to evaluate the clinical utility of N-terminal fragment of the brain natriuretic peptide (NT-pro-BNP), troponin T, transcoronary lactate gradient (TCLG) and C-reactive protein (CRP) as predictors of AF in patients undergoing isolated coronary artery bypass surgery (CABG). METHODS This study included 215 consecutive patients in sinus rhythm (SR) undergoing elective CABG between May 2007 and May 2008. The patients were grouped according to their respective postoperative rhythm into SR and AF groups. The data are presented as mean values+/-standard deviation, or medians with quartiles. RESULTS Fifty-five patients developed AF (26%). The preoperative NT-pro-BNP values were 273+/-347 and 469+/-629 pg ml(-1) in the SR and AF groups, respectively (p<0.0001). The postoperative NT-pro-BNP values were 3110+/-3600 pg ml(-1) in the SR and 4625+/-5640 pg ml(-1) in the AF groups (p=0.027). The transcoronary lactate gradient rose from the pre-cardiopulmonary bypass values to those observed 5 min after revascularisation in both groups (-0.05+/-0.37 to 0.39+/-0.46 mmol l(-1) (p<0.0001) in the SR group and -0.01+/-0.27 to 0.43+/-0.46 mmol l(-1) (p<0.0001) in the AF group). The CRP values increased from 6+/-13 to 163+/-88 mg l(-1) (p<0.0001) in the SR group, and from 6+/-16 to 163+/-104 mg l(-1) (p<0.0001) in the AF group. The dynamics of TCLG and CRP did not differ between the groups (p=0.71, p=0.44, respectively). The troponin T values on postoperative day 1 were significantly higher in the AF than the SR group (0.86 (0.49-2.1) ng ml(-1) vs 0.67 (0.37-1.16) ng ml(-1), p=0.046). The duration of cardiopulmonary bypass (CPB) was 85+/-24 min in the SR and 93+/-30 min in the AF group (p=0.05). Patients who developed AF were older (66+/-7 years vs 60+/-9 years, p<0.0001) and had a higher EuroSCORE (3.9+/-2.7 vs 2.9+/-2.2, p=0.009). Multivariate analysis identified age (p=0.0043), preoperative NT-pro-BNP (p=0.019) and duration of CPB (p=0.035) as independent predictors of AF. CONCLUSIONS Preoperative and postoperative NT-pro-BNP as well as TnT values were significantly higher in patients who subsequently developed AF. TCLG and CRP were not useful in identifying patients at higher risk for AF. Multivariate analysis identified age, preoperative NT-pro-BNP and duration of CPB as independent correlates of AF.

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

OBJECTIVES Chronic 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. METHODS Forty-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. RESULTS Fibrotic 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). CONCLUSIONS Atria 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).

The predictive value of platelet function point-of-care tests for postoperative blood loss and transfusion in routine cardiac surgery: a systematic review.

Excessive bleeding after cardiopulmonary bypass (CPB) operations remains to be a persistent problem and weak platelet function certainly contributes to bleeding diathesis. Antiplatelet therapy (APT) is an integral component of perioperative management in patients undergoing cardiac surgery procedures, both with and without use of CPB. In addition to individual variability in platelet function, different preoperative APT administration/discontinuation management further affects platelet function, which in turn may reflect bleeding tendency. However, the impact of drug-induced platelet inhibition on early postoperative bleeding extent remains difficult to predict. Herein, we reviewed the available evidence on the association between platelet function testing values and the extent of bleeding and transfusion requirements in early perioperative period. Currently, the association between platelet function measured by ex vivo assay and the occurrence of bleeding events remains uncertain. The intent of this review is to provide comprehensive literature insight into published evidence, investigating the possibility of platelet function tests to predict bleeding extent as well as transfusion requirements in cardiac surgery patients.

Results of extracorporeal life support implementation in routine clinical practice: single center experience

Aim To describe our experience in the clinical application of extracorporeal life support (ECLS) and analyze whether ECLS leads to acceptable clinical outcomes in patients with cardiac failure. Methods Data from clinical database of University Hospital Center Zagreb, Croatia, on 75 patients undergoing ECLS support from 2009 to 2014 due to cardiac failure were retrospectively analyzed. Outcomes were defined as procedural and clinical outcomes. ECLS as a primary procedure and ECLS as a postcardiotomy procedure due to inability to wean from cardiopulmonary bypass were analyzed. Results ECLS was used in 75 adult patients, and in 24 (32%) of those procedural success was noted. ECLS was implemented as a primary procedure in 36 patients and as a postcardiotomy procedure in 39 patients. Nine out of 39 (23.08%) patients had postcardiotomy ECLS after heart transplantation. Bleeding complications occurred in 30 (40%) patients, both in primary (11/36 patients) and postcardiotomy group (19/39 patients). ECLS was established by peripheral approach in 46 patients and by central cannulation in 27 patients. In 2 patients, combined cannulation was performed, with an inflow cannula placed into the right atrium and an outflow cannula placed into the femoral artery. Eleven patients treated with peripheral approach had ischemic complications. Conclusion ECLS is a useful tool in the treatment of patients with refractory cardiac failure and its results are encouraging in patients who otherwise have an unfavorable prognosis.

Bleeding and Thrombotic Events in Patients Undergoing Mechanical Circulatory Support: A Review of Literature

Bleeding and thrombotic events are among the most common complications detected in patients with mechanical circulatory support (MCS). Herein, we reviewed the available evidence on the prevalence, etiology, and management of bleeding and thrombotic events in patients following MCS procedures, such as implantation of both intra- and paracorporeal devices that generate either pulsatile or nonpulsatile flow. Extracorporeal life support procedures providing support to the failing heart and lungs were also reviewed. Most bleeding and thromboembolic events occur despite appropriate hemostatic and anticoagulation management based on conventional coagulation laboratory parameters. Prevalence of bleeding events in this population ranges between 5 and 81%. Wide range in prevalence of bleeding reported in literature may be explained by different devices with different anticoagulation protocols being used, as well as different definitions of bleeding outcomes. Although bleeding events are more common than thromboembolic events, the consequences of thrombotic events are often detrimental. Management of bleeding events remains challenging and measures to prevent and treat bleeding events are often followed by thromboembolic events. Therefore, a personalized approach based on point-of-care hemostatic tests and adjusted to device type and patient comorbidities is therefore warranted. To provide advanced understanding of hemostatic disturbances during MCS, prospective trials focused on bleeding and thromboembolic events as primary endpoints should be conducted. Better understanding of the underlying pathophysiology and a shift towards a personalized approach based on functional point-of-care hemostatic properties assessment may provide more favorable clinical outcomes. This should, however, be coupled with further technological improvements providing better device surface hemocompatibility as interaction between blood and device surface affects the hemostatic equilibrium.

Diagnostic accuracy of central venous saturation in estimating mixed venous saturation is proportional to cardiac performance among cardiac surgical patients

PURPOSE Advanced hemodynamic monitoring in cardiac surgery translates into improvement in outcomes. We evaluated the relationship between central venous (ScvO2) and mixed venous (SvO2) saturations over the early postoperative period. The adequacy of their interchangeability was tested in patients with varying degrees of cardiac performance. METHODS In this prospective observational study, we evaluated 156 consecutive cardiac surgical patients in an academic center. The ScvO2 and SvO2 data were harvested from 468 paired samples taken preoperatively (T0), after weaning from cardiopulmonary bypass (T1) and on postoperative day 1 (T2). RESULTS The relationship between ScvO2 and SvO2 was inconsistent, with inferior correlations in patients with lower cardiac indices (CI) (Pearson r(2) = 0.37 if CI ≤2.0 L/min per square meter vs r(2) = 0.73 if CI >2.0 L/min per square meter, both P < .01). Patients with lower CI also had wider 95% limits of agreement between SvO2 and ScvO2. The proportion of patients with a negative SvO2-ScvO2 gradient increased over time (48/156 [31%] at T0 to 73/156 [47%] at T2; P < .01). This subgroup more frequently required inotropes at T2 than patients with a positive SvO2-ScvO2 gradient (odds ratio, 6.46 [95% confidence interval, 0.81-51.87], P = .06) and also had higher serum lactate levels (1.5 ± 0.8 vs 1.0 ± 0.4; P < .01). CONCLUSIONS The diagnostic accuracy of ScvO2 for estimating SvO2 is proportional to cardiac performance. A negative SvO2-ScvO2 gradient at T2 correlated with inotropic support requirement, higher operative risk score, age, lactate level, and duration of cardiopulmonary bypass.

Combined surgical and angioplasty management of coronary artery aneurysms including the giant form.

Coronary artery aneurysms are a rare form of coronary artery disease. Due to the rarity of these aneurysms, particularly of the giant form, it is difficult to establish a standardized treatment. We report the case of a 65-year-old man who presented with symptoms of an acute coronary syndrome. A posterobasal myocardial infarction was diagnosed with a giant right coronary artery aneurysm as the underlying pathology. Two aneurysms of the left anterior descending artery were also revealed. The management strategy included ligation of the giant aneurysm coupled with distal coronary artery bypass grafting of the right coronary artery. This was complemented with a delayed percutaneous coronary intervention of the left anterior descending artery aneurysms.

IS local wound infection rate more important than long-term graft patency in coronary artery bypass grafting?

The Editor welcomes submiss section that consist of comm vant issues. Authors should: and five references. Type w misc/ifora.shtml for detailed cally via jtcvs.editorialman in the JTCVS will be cons the article was published. A an opportunity of offer a tim will be notified that the lett turned. artery bypass grafting (CABG) with yet longer follow-up data. In 1993, a single-center longitudinal randomized trial was initiated by the € Orebro group that compared no-touch (NT) and conventional SV graft harvesting. At a mean of 16 years, 27 patients per group, accounting for 72 conventional and 75 NT grafts, underwent computed tomographic angiography to assess graft patency. Of the NT grafts, 83% (62/75) were patent, only slightly lower than the 88% (42/ 48) patency of the left internal thoracic artery grafts and significantly higher than the 64% (46/72) patency of the conventional SV grafts. In the 1990s, at the same time as the introduction of the NT method, a minimally invasive endoscopic technique was developed for harvesting SV grafts. The main benefit of the endoscopic approach relates to the decrease in wound morbidity and patient satisfaction, based in part on superior cosmetic outcome, although the technique is of questionable cost-effectiveness because of the higher initial equipment costs. The data presented by Samano and associates support SV grafts in the battle for the position of graft of second choice in CABG and call into question the benefit of total arterial revascularization. Despite the benefits shown to date, the use of the NT technique for SV harvesting in CABG is still limited to only a few centers. Considering several reports on inferior patency of SV grafts harvested by means of endoscopy and the potential clinical benefit behind the improved patency of the NT technique, the question arises as to why surgeons are so reluctant to adopt the NT technique for harvesting SV grafts. Moreover, the adoption of endoscopic vein harvesting has assumed epidemic proportions and is considered the criterion standard for SV harvesting in the majority of centers in the United States despite those reports revealing inferior patency.