Uncomplicated Cardiac Surgery Research Articles

POStoperative INTELLiVENT-adaptive support VEntilation in cardiac surgery patients (POSITiVE) II—study protocol of a randomized clinical trial

BackgroundOne single-center randomized clinical trial showed that INTELLiVENT-adaptive support ventilation (ASV) is superior to conventional ventilation with respect to the quality of ventilation in post-cardiac surgery patients. Other studies showed that this automated ventilation mode reduces the number of manual interventions at the ventilator in various types of critically ill patients. In this multicenter study in patients post-cardiac surgery, we test the hypothesis that INTELLiVENT-ASV is superior to conventional ventilation with respect to the quality of ventilation.Methods“POStoperative INTELLiVENT-adaptive support VEntilation in cardiac surgery patients II (POSITiVE II)” is an international, multicenter, two-group randomized clinical superiority trial. In total, 328 cardiac surgery patients will be randomized. Investigators screen patients aged > 18 years of age, scheduled for elective cardiac surgery, and expected to receive postoperative ventilation in the ICU for longer than 2 h. Patients either receive automated ventilation by means of INTELLiVENT-ASV or ventilation that is not automated by means of a conventional ventilation mode. The primary endpoint is quality of ventilation, defined as the proportion of postoperative ventilation time characterized by exposure to predefined optimal, acceptable, and critical (injurious) ventilatory parameters in the first two postoperative hours. One major secondary endpoint is ICU team staff workload, captured by the ventilator software collecting manual settings on alarms. Patient-centered endpoints include duration of postoperative ventilation and length of stay in ICU.DiscussionPOSITiVE II is the first international, multicenter, randomized clinical trial designed to confirm that POStoperative INTELLiVENT-ASV is superior to non-automated conventional ventilation and secondary to determine if this closed-loop ventilation mode reduces ICU team staff workload. The results of POSITiVE II will support intensive care teams in their choices regarding the use of automated ventilation in postoperative care of uncomplicated cardiac surgery patients.Trial registrationClinicaltrials.gov NCT06178510. Registered on December 4, 2023.

The Postoperative Paradoxical Septum (POPS): A Comprehensive Review on Physio-Pathological Mechanisms.

The interventricular septum (IVS) is a core myocardial structure involved in biventricular coupling and performance. Physiologically, during systole, it moves symmetrically toward the center of the left ventricle (LV) and opposite during diastole. Several pathological conditions produce a reversal or paradoxical septal motion, such as after uncomplicated cardiac surgery (CS). The postoperative paradoxical septum (POPS) was observed in a high rate of cases, representing a unicum in the panorama of paradoxical septa as it does not induce significant ventricular morpho-functional alterations nor negative clinical impact. Although it was previously considered a postoperative event, evidence suggests that it might also appear during surgery and gradually resolve over time. The mechanism behind this phenomenon is still debated. In this article, we will provide a comprehensive review of the various theories generated over the past fifty years to explain its pathological basis. Finally, we will attempt to give a heuristic interpretation of the biventricular postoperative motion pattern based on the switch of the ventricular anchor points.

Diagnostic Agreement Between TEG5000 and TEG6S in the Assessment of Hemostasis in Pediatric Cardiac Surgery: A Prospective Non-inferiority Study.

Thromboelastography (TEG) is a point-of-care test (POCT) used to analyze the hemostatic properties of whole blood. TEG® 5000and TEG® 6s (Haemonetics Corp, USA) measure the same parameters describing clot viscoelasticity using different methodologies. The purpose of this study was to evaluate agreement between TEG5000 and TEG6s measurements. We analyzed prospectively collected tests resulting from paired blood samples in cardiac surgery pediatric patients at one hour (T0) and 24 h (T1) postoperatively. Each citrated sample was utilized for TEG® 5000 and TEG ®6s. Six specific TEG parameters were analyzed and compared: R kaolin time (RK), R kaolin heparinase (RKH) time, K kaolin time (KK), K kaolin heparinase time KH (KKH), Maximum Amplitude kaolin (MAK), Maximal Amplitude Kaolin Heparinase (MAKH). We enrolled 30 patients. Median (interquartile range) patients' age was 206 (20-597) days. All surgical patients underwent correction except 5 who were palliated. At T0, RK and RKH showed an average (standard deviation) % bias of 15.8 (31) and 16.1 (28), respectively, with similar results at T1. A % bias of -6 (23) and - 6 [15] in MAK was found at T0 and T1, respectively. Similarly, MAKH % bias was 1.5 (22) and 7.6 (29) at T0 and T1, respectively. At both timepoints, low % biases (< ± 6%) were demonstrated in KK and KKH. All parameters showed improved coagulation from T0 to T1, but without significant interaction between type of device and time. Analysis of the entire pool of 60 paired samples showed no agreement in diagnostic performance (within the range vs. outside the range) in 12 (20%), 5 (9.8%), 1 (1.7%), 4 (7.8%), 9 (15%), and 5 (9.8%) cases for RK, RKH, MAK, MAKH, KK and KKH, respectively. We observed substantial agreement in MAK and KK in a cohort of pediatric patients undergoing uncomplicated cardiac surgery. Our findings suggest that TEG®5000 and TEG®6s are interchangeable for assessing these parameters.

Paradoxical Septal Motion after Uncomplicated Cardiac Surgery: A Consequence of Altered Regional Right Ventricular Contractile Patterns.

Paroxysmal interventricular septal motion (PSM) is the movement of the septum toward the right ventricle (RV) during cardiac systole. It occurs frequently after uncomplicated cardiac surgery (CS), including coronary bypass (on-pump and off-pump), valve repair or replacement, and with all types of incisions (sternotomy or mini-thoracotomy). It sometimes resolves quickly but may persist for months or become permanent. Global RV systolic function, stroke volume and ejection fraction remain normal after uncomplicated CS, but regional contractile patterns are altered. There is a decrease in longitudinal shortening but an increase in transverse shortening in the endocardial and epicardial right ventricular muscle fibers, respectively. PSM is a secondary event as there is no loss of septal perfusion or thickening. The increased RV transverse shortening (free wall to septal fibers) may modify septal movement resulting in PSM that compensates for the reduced RV longitudinal shortening, thus preserving normal global right ventricular function.

Serum biomarkers of brain injury after uncomplicated cardiac surgery: Secondary analysis from a randomized trial.

BackgroundPostoperative cognitive dysfunction is common after cardiac surgery. Postoperative measurements of brain injury biomarkers may identify brain damage and predict cognitive dysfunction. We describe the release patterns of five brain injury markers in serum and plasma after uncomplicated cardiac surgery.MethodsSixty‐one elective cardiac surgery patients were randomized to undergo surgery with either a dextran‐based prime or a crystalloid prime. Blood samples were taken immediately before surgery, and 2 and 24 h after surgery. Concentrations of the brain injury biomarkers S100B, glial fibrillary acidic protein (GFAP), tau, neurofilament light (NfL) and neuron‐specific enolase (NSE)) and the blood–brain barrier injury marker β‐trace protein were analyzed. Concentrations of brain injury biomarkers were correlated to patients’ age, operation time, and degree of hemolysis.ResultsNo significant difference in brain injury biomarkers was observed between the prime groups. All brain injury biomarkers increased significantly after surgery (tau +456% (25th–75th percentile 327%−702%), NfL +57% (28%−87%), S100B +1145% (783%−2158%), GFAP +17% (−3%−43%), NSE +168% (106%−228%), while β‐trace protein was reduced (−11% (−17−3%). Tau, S100B, and NSE peaked at 2h, NfL and GFAP at 24 h. Postoperative concentrations of brain injury markers correlated to age, operation time, and/or hemolysis.ConclusionUncomplicated cardiac surgery with cardiopulmonary bypass is associated with an increase in serum/plasma levels of all the studied injury markers, without signs of blood–brain barrier injury. The biomarkers differ markedly in their levels of release and time course. Further investigations are required to study associations between perioperative release of biomarkers, postoperative cognitive function and clinical outcome.

Con: Extubating in the Operating Room After Cardiac Surgery Is Not Necessary

CARDIAC SURGERY PATIENTS are among the highest risk patients for postoperative pulmonary complications, acute kidney injury, and increased length of hospital stay. 1 Pahwa S Bernabei A Schaff H et al. Impact of postoperative complications after cardiac surgery on long-term survival. J Card Surg. 2021; 36: 2045-2052 Crossref PubMed Scopus (3) Google Scholar In an attempt to decrease these risks, enhanced recovery or fast-track pathways after cardiac surgery have gained traction in recent years. Early extubation is one area of such a pathway that has been shown to decrease the length of stay and reduce healthcare costs in this population. 2 Higgins TL. Pro: Early endotracheal extubation is preferable to late extubation in patients following coronary artery surgery. J Cardiothorac Vasc Anesth. 1992; 6: 488-493 Abstract Full Text PDF PubMed Scopus (113) Google Scholar While most will agree that extubation within 6 hours is ideal after uncomplicated cardiac surgery, there has been an increasing push to take it one step further and provide routine on-table extubation (OTE) after cardiac surgery. To date, there are no randomized controlled trials to support that OTE provides any further benefit over standard fast-track extubation and, thus, should not be routinely performed.

Comparing the Intellivent-ASV® Mode with Conventional Ventilation Modes during Weaning after Uncomplicated Cardiac Surgery

The objective: to compare efficacy and safety of Intellivent-ASV® with conventional ventilation modes during weaning in the patients after cardiac surgery.Subjects and methods. In this randomized controlled trial, 40 adult patients were ventilated with conventional ventilation modes and 40 with Intellivent-ASV after uncomplicated cardiac surgery. Eight physicians were involved in the study.Care of both groups was standardized, except for the modes of postoperative ventilation.We compared:- The physician’s workload, through accounting number of manual ventilator settings and time they spent near the ventilator in every group,- Duration of tracheal intubation in ICU,- Evaluation of ventilation safety by considering driving pressure, mechanical power, positive end expiratory pressure, and tidal volume level,- The frequency of adverse events, postoperative complications, and lethality.Results. There were significant differences in the duration of respiratory support in ICU: 226 ± 31 min (Intellivent Group) vs 271 ± 78 min (Control Group) (p = 0.0013).In Intellivent Group, the number of manual ventilator settings and time spent by physicians near the ventilator before tracheal extubation were significantly lower: 0 vs 4 (2–6), and 35 (25–53) sec vs 164 ± 69 sec respectively (p &lt; 0.001 in both cases).Intellivent-ASV provided significantly more protective ventilation through reduction in the driving pressure, tidal volume, FiO2 and PEEP levels but no difference was noted between paO2/FiO2 ratio. ∆P and Vt were significantly lower in Intellivent Group – ∆P on mechanical ventilation was 6 (5–7) cm H2O vs 7.25 (6.5–9.5) cm H2O (p &lt; 0.001); Vt on mechanical ventilation was 6 (5.2–7) vs 7 (6–9.5) ml/kg/PBW (p = 0.000003). PEEP and FiO2 levels were also significantly lower in Intellivent Group, PEEP on mechanical ventilation was 5 (5–7.5) cm H2O vs 7 (5–11.5) cm H2O and FiO2 level was 26 (22–30) % vs 34 (30–40) %.There were no significant differences between the groups in frequency of adverse events and duration of ICU and hospital stay.Conclusion. Application of Intellivent-ASV mode after uncomplicated cardiac surgery provides more protective mechanical ventilation and reduces the physician’s workload without compromising the quality of respiratory support and safety of patients.

Lung recruitment in the prone position after cardiac surgery: a randomised controlled study

BackgroundAtelectasis after cardiac surgery is common and promotes ventilation/perfusion mismatch, infection, and delayed discharge from critical care. Recruitment manoeuvres are often performed to reduce atelectasis. In severe respiratory failure, recruitment manoeuvres in the prone position may increase oxygenation, survival, or both. We compared the effects of recruitment manoeuvres in the prone vs supine position on lung aeration and oxygenation in cardiac surgical patients. MethodsSubjects were randomised to recruitment manoeuvres (40 cm H2O peak inspiratory pressure and 20 cm H2O PEEP for 30 s) in either the prone or supine position after uncomplicated cardiac surgery. The co-primary endpoints were lung aeration (end-expiratory lung volume measured by electrical impedance tomography (arbitrary units [a.u.]) and lung oxygenation (ratio of arterial oxygen partial pressure to fractional inspired oxygen [Pao2/FiO2 ratio]). Secondary outcomes included postoperative oxygen requirement and adverse events. ResultsThirty subjects (27% female; age, 48–81 yr) were recruited. Dorsal lung tidal volume was higher after prone recruitment manoeuvres (363 a.u.; 95% confidence intervals [CI], 283–443; n=15) after extubation, compared with supine recruitment manoeuvres (212 a.u.; 95% CI, 170–254; n=15; P<0.001). Prone recruitment manoeuvres increased dorsal end-expiratory lung volume by 724 a.u. (95% CI, 456–992) after extubation, compared with 163 a.u. decrease (95% CI, 73–252) after supine recruitment manoeuvres (P<0.001). The Pao2/FiO2 ratio after extubation was higher after prone recruitment manoeuvres (46.6; 95% CI, 40.7–53.0) compared with supine recruitment manoeuvres (39.3; 95% CI, 34.8–43.8; P=0.04). Oxygen therapy after extubation was shorter after prone (33 h [13]) vs supine recruitment manoeuvres (52 h [22]; P=0.01). No adverse events occurred. ConclusionsRecruitment manoeuvres in the prone position after cardiac surgery improve lung aeration and oxygenation. Clinical trial registrationNCT03009331.

Native Aortic Valve Endocarditis Complicated by Splenic Infarction and Giant Mitral-Aortic Intervalvular Fibrosa Pseudoaneurysm—A Case Report and Brief Review of the Literature

Background: Pseudoaneurysm of the mitral-aortic intervalvular fibrosa (P-MAIVF) is an unusual complication related to various injuries or conditions which involve the mitro-aortic region; it communicates with the left ventricular outflow tract and is associated with a high-risk of redoubtable complications or sudden death. The cerebral and splenic localizations are frequently seen as manifestations of systemic embolism in infective endocarditis. Currently, there are no specific recommendations related to the diagnosis, management, treatment, or further evolution of patients with P-MAIVF and concomitant splenic infarction. This paper presents the case of a 43-year-old Caucasian woman with a late diagnosis of mixed bicuspid aortic valve disease, affected by an under-detected and undertreated episode of infective endocarditis leading to asymptomatic P-MAIVF. Prime clinical and imagistic diagnosis of splenic infarction indicated further extended investigations were required to clarify the source of embolism. Methods: Integrated multimodality imaging techniques confirmed the unexpected diagnosis of P-MAIVF. Results: The case had a fatal outcome following an uncomplicated yet laborious cardiac surgery. Patient death was attributed to a malignant ventricular arrhythmia. Conclusion: The present case raises awareness by highlighting an unexplained and unexpected splenic infarction association with P-MAIVF as a result of infective endocarditis related to mixed bicuspid aortic valve disease.

Right ventricular transverse displacement increases following cardiac surgery: possibly compensating loss in tricuspid annular plane systolic excursion (TAPSE).

Right Ventricular (RV) output mostly derives from longitudinal shortening in normal hearts. However, following even uncomplicated cardiac surgery with preserved RV function a significant and sustained decrease in longitudinal contraction has been observed. How the RV compensates and sustains output in this setting remains unsettled. The aim of this study was to evaluate the RV contraction pattern by speckle tracking echocardiography to elucidate possible compensatory mechanisms mitigating the reduced RV longitudinal contraction after cardiac surgery. Thirty patients with normal preoperative ejection fraction and no valvulopathy underwent coronary artery bypass grafting (CABG) with the use of cardiopulmonary bypass (CPB). RV dedicated speckle tracking software measuring longitudinal and transverse displacement, as well as strain, was employed on transesophageal echocardiographic (TEE) images as part of the Right Ventricular Echocardiography in cardiac SurgEry (ReVERSE) study. Data was recorded at baseline (after anesthesia induction), immediately after CPB and upon chest closure. Tricuspid Annulus Plane Systolic Excursion (TAPSE) was reduced from 2.0 [1.6-2.5cm] to 0.8 [0.6-11mm] from baseline to after chest closure. RV longitudinal displacement was reduced from 6.1 [3.4-8.8mm] to 2.9 [0.4-5.4mm] at the same time-points. RV speckle tracking revealed concomitantly that transverse displacement of the free wall increased significantly from 1.2 [0-2.7mm] at baseline to 5.4 [3.6-7.2mm] after chest closure. RV speckle tracking strain did not change significantly. Increased transverse displacement likely compensates for reduction in RV longitudinal contraction following cardiac surgery and maintains cardiac output. The sustained output from the right ventricle was not related to an increased contractility.

Tricuspid annular plane systolic excursion is significantly reduced during uncomplicated coronary artery bypass surgery: A prospective observational study

ObjectivesLongitudinal shortening constitutes most of the right ventricle (RV) contraction in the normal heart. However, after even uncomplicated cardiac surgery with preserved RV function a significant and sustained decrease in longitudinal contraction expressed as a reduction in tricuspid annular plane systolic excursion (TAPSE) has been observed. Why and exactly when this happens remains unsettled. The aim of this study was to evaluate the magnitude and timing of changes in TAPSE in relation to sternotomy, pericardial opening, cardiopulmonary bypass (CPB), and chest closure. MethodsFifty patients with normal preoperative ejection fraction and no valvulopathy, who underwent coronary artery bypass grafting with the use of CPB, were included. TAPSE was assessed using transthoracic echocardiography (TTE) at baseline and immediately after chest closure. Transesophageal echocardiography was performed at the following time points: after (1) anesthesia induction and transthoracic echocardiography; (2) sternotomy; (3) pericardiotomy; (4) completion of CPB; and (5) chest closure. ResultsTAPSE was significantly reduced to approximately half of its initial value in all patients (from 22 [95% confidence interval, 21-23 mm] after anesthesia induction to 9 [95% confidence interval, 8-10 mm] after chest closure). No change was seen after pericardiotomy. The most prominent reduction (30%-40%) was observed after weaning from CPB. An additional significant decrease of 13% to 16% was seen after chest closure. ConclusionsTAPSE was consistently reduced to approximately half of its initial value after uncomplicated coronary artery bypass grafting surgery. The reduction happened mainly after weaning from CPB, possibly reflecting conformational change of the RV.

Low Transmission of Airway Pressures to the Abdomen in Mechanically Ventilated Patients With or Without Acute Respiratory Failure and Intra-Abdominal Hypertension.

Intra-abdominal pressure, measured at end expiration, may depend on ventilator settings and transmission of intrathoracic pressure. We determined the transmission of positive intrathoracic pressure during mechanical ventilation at inspiration and expiration into the abdominal compartment. We included 9 patients after uncomplicated cardiac surgery and 9 with acute respiratory failure. Intravesical pressures were measured thrice (reproducibility of 1.8%) and averaged, at the end of each inspiratory and expiratory hold maneuvers of 5 seconds. Transmission, the change in intra-abdominal over intrathoracic pressures from end inspiration to end expiration, was about 8%. End-expiratory intra-abdominal pressure was lower than "total" intra-abdominal pressure over the entire respiratory cycle by 0.34 cm H2O. It was 0.73 cm H2O higher than "true" intra-abdominal pressure over the entire respiratory cycle, taking transmission into account. The percentage error was 3% for total and 10% for true pressure. Results did not differ among patients with or without acute respiratory failure and decreased respiratory compliance or between those with (≥12 mm Hg, n = 5) or without intra-abdominal hypertension. Transmitted airway pressure only slightly affects intra-abdominal pressure in mechanically ventilated patients, irrespective of respiratory compliance and baseline intra-abdominal pressure values. End-expiratory measurements referenced against atmospheric pressure may suffice for clinical practice.

Effects of Acute Plasma Volume Expansion on Renal Perfusion, Filtration, and Oxygenation After Cardiac Surgery

Background In the present randomized study, we evaluated the differential effects of a colloid and a crystalloid fluid on renal oxygen delivery ( R D O 2 ), glomerular filtration (GFR), renal oxygen consumption ( R V ˙ O 2 ), and the renal oxygen supply–demand relationship (i.e. renal oxygenation) after cardiac surgery with cardiopulmonary bypass. Methods Thirty patients with normal preoperative renal function, undergoing uncomplicated cardiac surgery, were studied in the intensive care unit in the early postoperative period. Patients were randomized to receive a bolus dose of either a crystalloid (Ringers-acetate® 20 ml kg−1, n=15) or a colloid solution (Venofundin® 10 ml kg−1, n=15). Systemic haemodynamics were measured via a pulmonary artery catheter. Renal blood flow and GFR were measured by the renal vein retrograde thermodilution technique and by renal extraction of 51Cr-EDTA (=filtration fraction). Arterial and renal vein blood samples were obtained for measurements of renal oxygen delivery ( R D O 2 ) and R V ˙ O 2 . Renal oxygenation was estimated from the renal oxygen extraction. Results Despite an increase in cardiac index and renal blood flow with both fluids, neither of the fluids improved R D O 2 , because they both induced haemodilution. The GFR increased in the crystalloid (28%) but not in the colloid group. The crystalloid increased the filtration fraction (24%) and renal oxygen extraction (23%), indicating that the increase in GFR, the major determinant of R V ˙ O 2 , was not matched by a proportional increase in R D O 2 . Conclusions Neither the colloid nor the crystalloid improved R D O 2 when used for postoperative plasma volume expansion. The crystalloid-induced increase in GFR was associated with impaired renal oxygenation, which was not seen with the colloid. Clinical trial registration NCT01729364.

Effects of acute plasma volume expansion on renal perfusion, filtration, and oxygenation after cardiac surgery: a randomized study on crystalloid vs colloid

In the present randomized study, we evaluated the differential effects of a colloid and a crystalloid fluid on renal oxygen delivery (RD(O2)), glomerular filtration (GFR), renal oxygen consumption ((RV(O2))), and the renal oxygen supply-demand relationship (i.e., renal oxygenation) after cardiac surgery with cardiopulmonary bypass. Thirty patients with normal preoperative renal function, undergoing uncomplicated cardiac surgery, were studied in the intensive care unit in the early postoperative period. Patients were randomized to receive a bolus dose of either a crystalloid (Ringers-acetate 20 ml kg(-1), n=15) or a colloid solution (Venofundin) 10 ml kg(-1), n=15). Systemic haemodynamics were measured via a pulmonary artery catheter. Renal blood flow and GFR were measured by the renal vein retrograde thermodilution technique and by renal extraction of 51Cr-EDTA (=filtration fraction). Arterial and renal vein blood samples were obtained for measurements of renal oxygen delivery (RD(O2)) and RV(O2). Renal oxygenation was estimated from the renal oxygen extraction. Despite an increase in cardiac index and renal blood flow with both fluids, neither of the fluids improved RD(O2), because they both induced haemodilution. The GFR increased in the crystalloid (28%) but not in the colloid group. The crystalloid increased the filtration fraction (24%) and renal oxygen extraction (23%), indicating that the increase in GFR, the major determinant of RV(O2), was not matched by a proportional increase in RD(O2). Neither the colloid nor the crystalloid improved RD(O2) when used for postoperative plasma volume expansion. The crystalloid-induced increase in GFR was associated with impaired renal oxygenation, which was not seen with the colloid. NCT01729364.

Postoperative red blood cell transfusion and morbid outcome in uncomplicated cardiac surgery patients

To evaluate postoperative red blood cell (RBC) transfusion and its association with postoperative cardiac events and multiorgan morbidity in uncomplicated cardiac surgery patients. A cohort of 945 patients from the 5,436 coronary artery bypass grafting patients enrolled in the international Multicenter Study of Perioperative Ischemia (McSPI) Epidemiology II (EPI II) study was investigated. Inclusion criteria were low to moderate risk profile, postoperative hemoglobin level ≥ 10 g/dl, minimal postoperative blood loss, and no evidence of any morbid event on the day of surgery. RBC transfusion was assessed during the first 24 postoperative hours and cardiac as well as multiorgan outcomes from postoperative day 2 to hospital discharge. Multivariate analysis was applied to assess the effect of RBC transfusion on multiorgan outcomes. A secondary propensity score analysis was performed in 4,465 patients without early postoperative morbid outcomes. Transfused patients (193/945, 20.4%) were more likely to suffer cardiac events (P = 0.03), harvest-site infection (P = 0.002), and composite morbidity outcome (P = 0.04). RBC transfusion was associated with cardiac events on multivariate as well as on propensity score analysis (adjusted odds ratio, 1.39; 95% confidence interval, 1.01-1.92; P = 0.04), and with harvest-site infection on multivariate analysis. Additionally, propensity score analysis suggested possible associations of RBC transfusion with increased risks for composite morbidity outcome and in-hospital mortality, renal morbidity, pneumonia, and mediastinitis. The data suggest a potential association between postoperative RBC transfusion and increased morbidity for cardiac surgery patients with low to moderate mortality risk profiles, adequate hemoglobin levels, and low bleeding rates.

Clinician's Commentary

Clinician's Commentary

Abnormal Motion of the Interventricular Septum after Coronary Artery Bypass Graft Surgery: Comprehensive Evaluation with MR Imaging

ObjectiveTo define the mechanism associated with abnormal septal motion (ASM) after coronary artery bypass graft surgery (CABG) using comprehensive MR imaging techniques.Materials and MethodsEighteen patients (mean age, 58 ± 12 years; 15 males) were studied with comprehensive MR imaging using rest/stress perfusion, rest cine, and delayed enhancement (DE)-MR techniques before and after CABG. Myocardial tagging was also performed following CABG. Septal wall motion was compared in the ASM and non-ASM groups. Preoperative and postoperative results with regard to septal wall motion in the ASM group were also compared. We then analyzed circumferential strain after CABG in both the septal and lateral walls in the ASM group.ResultsAll patients had normal septal wall motion and perfusion without evidence of non-viable myocardium prior to surgery. Postoperatively, ASM at rest and/or stress state was documented in 10 patients (56%). However, all of these had normal rest/stress perfusion and DE findings at the septum. Septal wall motion after CABG in the ASM group was significantly lower than that in the non-ASM group (2.1±5.3 mm vs. 14.9±4.7 mm in the non-ASM group; p < 0.001). In the ASM group, the degree of septal wall motion showed a significant decrease after CABG (preoperative vs. postoperative = 15.8±4.5 mm vs. 2.1±5.3 mm; p = 0.007). In the ASM group after CABG, circumferential shortening of the septum was even larger than that of the lateral wall (-20.89±5.41 vs. -15.41±3.7, p < 0.05)ConclusionAbnormal septal motion might not be caused by ischemic insult. We suggest that ASM might occur due to an increase in anterior cardiac mobility after incision of the pericardium.

CD64, a marker of leucocyte activation kinetics after uncomplicated cardiac surgery

The aim of this study was to assess the CD64 kinetics after normal cardiac surgery, an essential step to define the potential use of CD64 as an early and specific infectious marker in this postoperative setting. CD64 is a high-affinity receptor for the Fc portion of IgG. It is weakly expressed on the polynuclear neutrophils (PMNs) at rest [1,2] but increases specifically after bacterial stimulation. Thus, CD64 analysis is proposed as an early infectious marker.

Troponin is superior to electrocardiogram and creatinine kinase MB for predicting clinically significant myocardial injury after coronary artery bypass grafting

Cardiac biomarkers are routinely elevated after uncomplicated cardiac surgery to levels considered diagnostic of myocardial infarction in ambulatory populations. We investigated the diagnostic power of electrocardiogram (ECG) and cardiac biomarker criteria to predict clinically relevant myocardial injury using benchmarks of mortality and increased hospital length of stay (HLOS) in patients undergoing coronary artery bypass graft (CABG) surgery. Perioperative ECGs, creatinine kinase MB fraction, and cardiac troponin I (cTnI) were assessed in 545 primary CABG patients. None of the ECG criteria for myocardial injury predicted mortality or HLOS. However, post-operative day (POD) 1 cTnI levels independently predicted 5-year mortality (hazard ratio = 1.42; 95% CI 1.14-1.76 for each 10 microg/L increase; P = 0.009), while adjusting for baseline demographic characteristics and perioperative risk factors. Moreover, cTnI was the only biomarker that significantly improved the prediction of 5-year mortality estimated by the logistic Euroscore (P = 0.02). Furthermore, the predictive value of cTnI for 5-year mortality was replicated in a separately collected cohort of 1031 CABG patients using cardiac troponin T. Electrocardiogram diagnosis of post-operative myocardial injury after CABG does not independently predict an increased risk of 5-year mortality or HLOS. Conversely, cTnI is independently associated with an increased risk of mortality and prolonged HLOS.

A Randomized Controlled Trial of Cell Salvage in Routine Cardiac Surgery

Previous trials have indicated that cell salvage may reduce allogeneic blood transfusion during cardiac surgery, but these studies have limitations, including inconsistent use of other blood transfusion-sparing strategies. We designed a randomized controlled trial to determine whether routine cell salvage for elective uncomplicated cardiac surgery reduces blood transfusion and is cost effective in the setting of a rigorous transfusion protocol and routine administration of antifibrinolytics. Two-hundred-thirteen patients presenting for first-time coronary artery bypass grafting and/or cardiac valve surgery were prospectively randomized to control or cell salvage groups. The latter group had blood aspirate during surgery and mediastinal drainage the first 6 h after surgery processed in a cell saver device and autotransfused. All patients received tranexamic acid and were subjected to an algorithm for red blood cell and hemostatic blood factor transfusion. There was no difference between the two groups in the proportion of patients exposed to allogeneic blood (32% in both groups, relative risk 1.0 P = 0.89). At current blood products and cell saver prices, the use of cell salvage increased the costs per patient by a minimum of $103. When patients who had mediastinal re-exploration for bleeding were excluded (as planned in the protocol), significantly fewer units of allogeneic red blood cells were transfused in the cell salvage compared with the control group (65 vs 100 U, relative risk 0.71 P = 0.04). In patients undergoing routine first-time cardiac surgery in an institution with a rigorous blood conservation program, the routine use of cell salvage does not further reduce the proportion of patients exposed to allogeneic blood transfusion. However, patients who do not have excessive bleeding after surgery receive significantly fewer units of blood with cell salvage. Although the use of cell savage may reduce the demand for blood products during cardiac surgery, this comes at an increased cost to the institution.