Does a Platelet Transfusion Independently Affect Bleeding and Adverse Outcomes in Cardiac Surgery?

BACKGROUND: Conflicting results have been reported concerning the effect of platelet transfusion on several outcomes. The aim of this study was to assess the independent effect of a single early intraoperative platelet transfusion on bleeding and adverse outcomes in cardiac surgery patients. METHODS: For this observational study, 23,860 cardiac surgery patients were analyzed. Patients who received one early (shortly after cardiopulmonary bypass while still in the operating room) platelet transfusion, and no other transfusions, were defined as the intervention group. By matching the intervention group 1:3 to patients who received no early transfusion with most comparable propensity scores, the reference group was identified. RESULTS: The intervention group comprised 169 patients and the reference group 507. No difference between the groups was observed concerning reinterventions, thromboembolic complications, infections, organ failure, and mortality. However, patients in the intervention group experienced less blood loss and required vasoactive medication 139 of 169 (82%) versus 370 of 507 (74%; odds ratio, 1.65; 95% CI, 1.05 to 2.58), prolonged mechanical ventilation 92 of 169 (54%) versus 226 of 507 (45%; odds ratio, 1.47; 94% CI, 1.03 to 2.11), prolonged intensive care 95 of 169 (56%) versus 240 of 507 (46%; odds ratio, 1.49; 95% CI, 1.04 to 2.12), erythrocytes 75 of 169 (44%) versus 145 of 507 (34%; odds ratio, 1.55; 95% CI, 1.08 to 2.23), plasma 29 of 169 (17%) versus 23 of 507 (7.3%; odds ratio, 2.63; 95% CI, 1.50-4.63), and platelets 72 of 169 (43%) versus 25 of 507 (4.3%; odds ratio, 16.4; 95% CI, 9.3-28.9) more often compared to the reference group. CONCLUSIONS: In this retrospective analysis, cardiac surgery patients receiving platelet transfusion in the operating room experienced less blood loss and more often required vasoactive medication, prolonged ventilation, prolonged intensive care, and blood products postoperatively. However, early platelet transfusion was not associated with reinterventions, thromboembolic complications, infections, organ failure, or mortality.

Intraoperative Anemia and Single Red Blood Cell Transfusion During Cardiac Surgery: An Assessment of Postoperative Outcome Including Patients Refusing Blood Transfusion.

OBJECTIVES: Increasing evidence suggests benefits from restrictive red blood cell transfusion (RBC) thresholds in major surgery and critically ill patients. However, these benefits are not obvious in cardiac surgery patients with intraoperative anemia. The authors examined the association between uncorrected hemoglobin (Hb) levels and selected postoperative outcomes as well as the effects of RBCs. DESIGN: Cohort study with prospectively collected data from a cardiac surgery registry. SETTING: A major cardiac surgical hospital within the Netherlands, which is also a referral center for Jehovah's Witnesses. PARTICIPANTS: Patients (23,860) undergoing cardiac surgery between 1997 and 2013. INTERVENTIONS: Comparisons were done in patients with intraoperative nadir Hb<8 g/dL and/or an Hb decrease ≥ 50%. Comparison (A) between Jehovah's Witnesses (Witnesses) and matched non-Jehovah's Witnesses (non-Witnesses) transfused with 1 unit of RBC, and comparison (B) between patients given 1 unit of RBC intraoperatively versus matched non-transfused patients. MEASUREMENTS AND MAIN RESULTS: Postoperative outcomes were myocardial infarction, renal replacement therapy, stroke, and death. With propensity matching, the authors optimized exchangeability of the compared groups. Adverse outcomes increased with a decreasing Hb both among Witnesses and among non-Witnesses. The incidence of postoperative complications did not differ between Witnesses and matched non-Witnesses who received RBC (adjusted odds ratio 1.44, 95% confidence interval 0.63-3.29). Similarly, postoperative complications did not differ between patients who received a red cell transfusion and matched patients who did not (adjusted odds ratio 0.94, confidence interval 0.72-1.23). CONCLUSION: Intraoperative anemia is associated with adverse outcomes after cardiac surgery, and a single RBC transfusion does not seem to influence these outcomes.

Defining indications for selective chest radiography in the first 24 hours after cardiac surgery.

OBJECTIVE: In the intensive-care unit (ICU), chest radiographs (CXRs) are frequently obtained routinely for postoperative cardiac surgery patients, despite the fact that the efficacy of routine CXRs is known to be low. We investigated the efficacy and safety of CXRs performed after cardiac surgery for specified indications only. METHODS: In this observational cohort study, we prospectively included all patients who underwent conventional major cardiac surgery by median sternotomy in the year 2012. On-demand CXRs could be obtained during the first postoperative period for specified indications only. A routine control CXR was performed on the morning of the first postoperative day for all patients who had not undergone a CXR before that time. The diagnostic and therapeutic efficacy values were calculated for all CXRs. Differences were tested using Fisher's exact test or χ(2) analysis. RESULTS: A total of 1102 consecutive cardiac surgery patients were included in this study. The diagnostic efficacy of CXRs for major abnormalities was higher for the postoperative on-demand CXRs (n = 301; 27%) than for the routine CXRs taken the morning after surgery (n = 801; 73%) (6.6% vs 2.7%, P = .004). The therapeutic efficacy was higher for the on-demand CXRs, whereas the need for intervention after the next-morning, routine CXRs was limited to 5 patients (4.0% vs 0.6%, P < .001). None of these patients experienced a major adverse event. CONCLUSIONS: Defining clear indications for selective CXRs after cardiac surgery is effective and seems to be safe. This approach may significantly reduce the total number of CXRs performed, and will increase their efficacy.

The value of routine chest radiographs after minimally invasive cardiac surgery: an observational cohort study.

BACKGROUND: Chest radiographs (CXRs) are obtained frequently in postoperative cardiac surgery patients. The diagnostic and therapeutic efficacy of routine CXRs is known to be low and the discussion regarding the safety of abandoning these CXRs after cardiac surgery is still ongoing. We investigated the value of routine CXRs directly after minimally invasive cardiac surgery. METHODS: We prospectively included all patients who underwent minimally invasive cardiac surgery by port access, ministernotomy or bilateral video-assisted thoracoscopy (VATS) in the year 2012. A direct postoperative CXR was performed on all patients at ICU arrival. All CXR findings were noted, including whether they led to an intervention or not. The results were compared to the postoperative CXR results in patients who underwent conventional cardiac surgery by full median sternotomy over the same period. MAIN RESULTS: A total of 249 consecutive patients were included. Most of these patients underwent valve surgery, rhythm surgery or a combination of both. The diagnostic efficacy for minor findings was highest in the port access and bilateral VATS groups (56% and 63% versus 28% and 45%) (p < 0.005). The diagnostic efficacy for major findings was also higher in these groups (8.9% and 11% versus 4.3% and 3.8%) (p = 0.010). The need for an intervention was most common after minimally invasive surgery by port access, although this difference was not statistically significant (p = 0.056). CONCLUSIONS: The diagnostic efficacy of routine CXRs performed after minimally invasive cardiac surgery by port access or bilateral VATS is higher than the efficacy of CXRs performed after conventional cardiac surgery. A routine CXR after these procedures should still be considered.

Association of perioperative troponin and atrial fibrillation after coronary artery bypass grafting.

OBJECTIVES: Prediction of atrial fibrillation (AF) after coronary artery bypass grafting (CABG) may lead to preventive or early treatment and improved outcome. We investigated the association of serial perioperative cardiac troponin T (cTNT) measurements with postoperative AF in patients undergoing CABG. METHODS: In a retrospective analysis of prospectively collected data, 3148 patients undergoing elective CABG were evaluated. cTNT values were routinely determined before the start of surgery (cTNT0), at arrival on the intensive care unit (cTNT1) and 8-12 h later (cTNT2). Measurement of cTNT was continued until the peak value was reached. The development of AF during hospital stay was scored. The association between cTNT (cTNT0, cTNT1, cTNT2 and cTNTmax in first 48 h) and AF was calculated in univariable and multivariable analysis. RESULTS: AF occurred in 1080 (34%) patients. cTNT0, cTNT2 and cTNTmax were significantly and positively associated with postoperative AF (P < 0.001) in a univariable analysis, whereas a trend was seen for cTNT1 (P = 0.051). Advanced age, inotropic support and postoperative infection were independently associated with postoperative AF after logistic regression analysis, but cTNT was not. Categorizing patients by inotropic support into categories of inotropic support duration (none, <48 h, >48 h), the mean cTNT values were significantly higher among patients with AF in each category (all P < 0.001). Perioperative cTNT was significantly higher in patients with postoperative complications, longer hospital stay and reduced in-hospital survival. CONCLUSIONS: Perioperative cTNT is univariably associated with postoperative AF after CABG, but not independently. Further, no clinically useful cut-off point for preventive or early treatment could be identified. Both perioperative cTNT and postoperative AF are associated with negative outcome and prolonged hospital stay.

The clinical value of routine chest radiographs in the first 24 hours after cardiac surgery.

BACKGROUND: Chest radiographs (CXRs) are obtained frequently in the intensive care unit (ICU). Whether these CXRs should be performed routinely or on clinical indication only is often debated. The aim of our study was to investigate the incidence and clinical significance of abnormalities found on routine postoperative CXRs in cardiac surgery patients and whether a restricted use of CXRs would influence the number of significant findings. METHODS: We prospectively included all consecutive patients who underwent cardiac surgery during a 2-month period. Two or three CXRs were performed in the first 24 hours of ICU stay. After ICU admission and after drain removal, a clinical assessment was performed before a CXR was obtained. All CXR abnormalities were noted and it was also noted whether they led to an intervention. For the admission CXR and the drain removal CXR, a comparison was made between CXRs clinically indicated by the physician and those not clinically indicated. RESULTS: Two hundred fourteen patients were included. The majority of patients underwent coronary arterial bypass grafting (60%), heart valve surgery (21%), or a combination of these (14%). In total, 534 CXRs were performed (2.5 per patient). Abnormalities were found on 179 CXRs (33.5%) and 13 CXR results led to an intervention (2.4%). The association between clinically indicated CXRs and the presence of CXR abnormalities was poor. For 32 (10%) of the 321 admission and drain removal CXRs, clinical indications were stated by the physician beforehand. If these CXRs would not have been performed routinely, 68 abnormalities would have been missed, of which 5 led to an intervention. CONCLUSIONS: Partial elimination of routine CXRs in the first 24 hours after cardiac surgery seems possible for the majority of patients, but it is limited by the insensitivity of clinical assessment in predicting clinically important abnormalities detectable by CXRs.

Persistent cortical blindness after a thoracic epidural test dose of bupivacaine.

Thoracic epidural anesthesia is considered as an essential component of the perioperative care for patients undergoing lung resection. Although neurologic adverse events have been associated with this technique, permanent injury is rare. These events primarily involve the peripheral nervous system; for example, nerve root injury. We present a case of persistent cortical blindness after a test dose of bupivacaine was administered into an uneventfully placed thoracic epidural catheter.

Bayesian networks for multivariate data analysis and prognostic modelling in cardiac surgery.

Prognostic models are tools to predict the outcome of disease and disease treatment. These models are traditionally built with supervised machine learning techniques, and consider prognosis as a static, one-shot activity. This paper presents a new type of prognostic model that builds on the Bayesian network methodology that implements a dynamic, process-oriented view on prognosis. In contrast to traditional prognostic models, prognostic Bayesian networks explicate the scenarios that lead to disease outcomes, and can be used to update predictions when new information becomes available. A recursive data analysis strategy for inducing prognostic Bayesian networks from medical data is presented, and applied to data from the field of cardiac surgery. The resulting model outperformed a model that was constructed with off-the-shelf Bayesian network learning software, and had similar performance as class probability trees.

Prognostic Bayesian networks I: rationale, learning procedure, and clinical use.

Prognostic models are tools to predict the future outcome of disease and disease treatment, one of the fundamental tasks in clinical medicine. This article presents the prognostic Bayesian network (PBN) as a new type of prognostic model that builds on the Bayesian network methodology, and implements a dynamic, process-oriented view on prognosis. A PBN describes the mutual relationships between variables that come into play during subsequent stages of a care process and a clinical outcome. A dedicated procedure for inducing these networks from clinical data is presented. In this procedure, the network is composed of a collection of local supervised learning models that are recursively learned from the data. The procedure optimizes performance of the network's primary task, outcome prediction, and handles the fact that patients may drop out of the process in earlier stages. Furthermore, the article describes how PBNs can be applied to solve a number of information problems that are related to medical prognosis.

Prognostic Bayesian networks II: an application in the domain of cardiac surgery.

A prognostic Bayesian network (PBN) is new type of prognostic model that implements a dynamic, process-oriented view on prognosis. In a companion article, the rationale of the PBN is described, and a dedicated learning procedure is presented. This article presents an application here of in the domain of cardiac surgery. A PBN is induced from clinical data of cardiac surgical patients using the proposed learning procedure; hospital mortality is used as outcome variable. The predictive performance of the PBN is evaluated on an independent test set, and results were compared to the performance of a network that was induced using a standard algorithm where candidate networks are selected using the minimal description length principle. The PBN is embedded in the prognostic system ProCarSur; a prototype of this system is presented. This application shows PBNs as a useful prognostic tool in medical processes. In addition, the article shows the added value of the PBN learning procedure.

Psychotic symptoms in patients undergoing coronary artery bypass grafting and heart valve operation.

OBJECTIVE: Delirium on internal medicine and surgical wards of the general hospital is associated with several predisposing and precipitating factors as well as adverse outcomes. Whether psychosis, the symptom of delirium that may be recognized most promptly, is similarly associated with these factors and outcomes is largely unknown. METHODS: Eight thousand one hundred and thirty-nine consecutive patients undergoing coronary artery bypass grafting and/or heart valve operation were screened for preoperative predisposing factors and postoperative psychotic symptoms between January 1999 and July 2004. Data on per- and postoperative precipitating factors were collected in 4942 patients enrolled between January 2001 and July 2004. Data were examined using logistic regression to estimate odds ratios. RESULTS: The rate of severe psychotic symptoms was 2.1% (n=168). Higher age, renal failure, dyspnoea, heart failure, and left ventricle hypertrophy were independent preoperative predisposing factors. Peroperative hypothermia (<33 degrees C), hypoxemia, low hematocrit, renal failure, increased sodium, infection and stroke were independent precipitating factors. Psychotic symptoms were independently associated with a prolonged length of stay on the intensive care unit (odds ratio 7.8; 95% confidence interval 5.6-11), multi-organ failure or shock (3.2; 95% CI: 2.2-4.9), cardiopulmonary resuscitation (3.6; 95% CI: 2.1-6.2), and in-hospital death after surgery (2.1; 95% CI: 1.1-4.1). CONCLUSIONS: Psychotic symptoms are independently associated with several chronic and peroperative problems (including mild hypothermia during surgery), closely resembling those for delirium (with and without psychotic symptoms). Psychotic symptoms are also independently associated with adverse outcomes. Prompt diagnostic and therapeutic intervention aimed at the underlying problem may improve outcomes.

A phase III, double-blind, placebo-controlled, multicenter study on the efficacy of recombinant human antithrombin in heparin-resistant patients scheduled to undergo cardiac surgery necessitating cardiopulmonary bypass.

BACKGROUND: The study evaluated the efficacy of recombinant human antithrombin (rhAT) for restoring heparin responsiveness in heparin resistant patients undergoing cardiac surgery. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled study in heparin-resistant patients undergoing cardiac surgery with cardiopulmonary bypass. Heparin resistance was diagnosed when the activated clotting time was less than 480 s after 400 U/kg heparin. Fifty-four heparin-resistant patients were randomized. One cohort received 75 U/kg rhAT, and the other received normal saline. If the activated clotting time remained less than 480 s, this was considered treatment failure, and 2 units fresh frozen plasma was transfused. Patients were monitored for adverse events. RESULTS: Only 19% of patients in the rhAT group received fresh frozen plasma, compared with 81% of patients in the placebo group (P < 0.001). During their hospitalization, 48% of patients in the rhAT group received fresh frozen plasma, compared with 85% of patients in the placebo group (P = 0.009). Patients in the placebo group required higher heparin doses (P < 0.005) for anticoagulation. There was no increase in serious adverse events associated with rhAT. There was increased blood loss 12 h postoperatively (P = 0.05) with a trend toward increased 24-h bleeding in the rhAT group (P = 0.06). There was no difference between the groups in blood and platelet transfusions. CONCLUSION: Treatment with 75 U/kg rhAT is effective in restoring heparin responsiveness and promoting therapeutic anticoagulation in the majority of heparin-resistant patients. Treating heparin-resistant patients with rhAT may decrease the requirement for heparin and fresh frozen plasma.

Predictive models for thoracic aorta surgery. Is the Euroscore the optimal risk model in the Netherlands?

Prediction models do not optimally perform in the case of aorta surgery. We tried to define models that predict intensive care death for patients who underwent thoracic aorta surgery in the Netherlands. Therefore, we used data of 1290 patients who underwent interventions on the thoracic aorta from 1997 to 2002 which were prospectively collected in seven centers. One outcome was examined: intensive care death. Predicting models were made by multiple logistic regression analysis. The area under the receiver operating characteristics curve was used to study the discriminatory abilities of these models. We compared the models with the Euroscore. Eleven percent of the patients died during operation or on intensive care. Age, creatinine level >/=150 mumol/l, poor left ventricular ejection fraction and urgent indication were most related with intensive care-death. Prolonged extracorporal circulation and deep hypothermia were also of importance in the peri-operative model. The models performed better than the Euroscore. We conclude that the developed models perform relatively well in discriminating patients with respect to intensive care-death and even better than the Euroscore.

Outcome prediction in coronary artery bypass grafting and valve surgery in the Netherlands: development of the Amphiascore and its comparison with the Euroscore.

OBJECTIVES: (1) To define models that predict in-hospital death, major adverse cardiac events and extended intensive care unit duration for patients who underwent coronary artery bypass grafting (CABG), a heart valve operation or combined; and (2) to validate the Euroscore model in our population. METHODS: Data of all 7282 patient who underwent a CABG and/or heart valve operation in 1997-2001 were prospectively collected. Three outcomes were examined: in-hospital death, major adverse cardiac events (MACE) and extended length of stay on intensive care (ELOS). Predicting models were made by multivariate logistic regression. The patient population was randomly divided in a derivation (two thirds) and a validation (one third) set. Area under the receiver operating characteristics curve (AUC) was used to study the discriminatory abilities of these models and the Euroscore. Hosmer-Lemeshow goodness-of-fit was used to study calibration of the predictive models. RESULTS: 2.4% of the patients died in-hospital, 17% of the patients had a MACE and 14% had ELOS. The models for in-hospital mortality and ELOS had a good validation (AUC 0.84 and 0.79, respectively). The validation for MACE was moderate (receiver-operating characteristic, ROC 0.67). All models were well calibrated. The validation of the Euroscore was as good as our model for in-hospital mortality (ROC 0.84). CONCLUSIONS: The Amphia score performs as well as the Euroscore in discriminating patients with respect to in-hospital death. Our models for predicting major adverse cardiac events and extended length of stay on intensive care may be useful tools in categorising patients in various subgroups of risk for postoperative morbidity.