Postoperative stroke assessment inconsistencies in cardiac surgery: Contributors to higher stroke-related mortality?

OBJECTIVES: In-hospital stroke mortality is surprisingly much worse than for strokes occurring outside of the hospital. Cardiac surgery patients are amongst the highest risk groups for in-hospital stroke and experience high stroke-related mortality. Variability in institutional practices appears to play an important role in the diagnosis, management, and outcome of postoperative stroke. We therefore tested the hypothesis that variability in postoperative stroke management of cardiac surgical patients exists across institutions. MATERIALS AND METHODS: A 13 item survey was employed to determine postoperative stroke practice patterns for cardiac surgical patients across 45 academic institutions. RESULTS: Less than half (44%) reported any formal clinical effort to preoperatively identify patients at high risk for postoperative stroke. Epiaortic ultrasonography for the detection of aortic atheroma, a proven preventative measure, was routinely practiced in only 16% of institutions. Forty-four percent (44%) reported not knowing whether a validated stroke assessment tool was utilized for the detection of postoperative stroke, and 20% reported that validated tools were not routinely used. All responders, however, confirmed the availability of stroke intervention teams. CONCLUSIONS: Adoption of a best practices approach to the management of postoperative stroke is highly variable and may improve outcomes in postoperative stroke after cardiac surgery.

Aggressive invasive recurrence of a right atrial myxofibrosarcoma.

A 58-year-old man presented with left-sided chest discomfort 9 years ago. At that time a 12-centimeter extrapleural mass was resected via left thoracotomy. Surgical pathology revealed a low-grade myxofibrosarcoma. Since that time, he had undergone three separate resections of recurrent left extrapleural masses with sternotomy and thoracotomy. He proceeded to have a five-year disease-free interval after which a pericardial mass invading into the right atrial free wall, the atrioventricular groove, and the right coronary artery was identified. Surgical resection was performed with negative margins and the right atrium and atrioventricular groove were reconstructed without any residual tricuspid regurgitation.

Very low rate of patient-related adverse events associated with the use of intraoperative cell salvage.

BACKGROUND: The rate of patient-related clinical adverse events (AEs) associated with the use of intraoperative cell salvage (ICS) was analyzed. STUDY DESIGN AND METHODS: The perfusion service and electronic risk management databases in a nine-hospital regional health care system were reviewed over an approximately 11-year period. The number of ICS cases performed during this period and basic patient demographics were also extracted. RESULTS: There were 43,198 patients for whom ICS was utilized during the study period. Recovered blood was returned to 33,351 (77.2%) patients. Electronic comments on the ICS procedure were found in 2348 of 33,351 (7.0%) cases. The vast majority of comments (2203/2348, 93.8%) described minor events that did not lead to patient-related AEs such as the surgeon requested higher than normal suction pressure or that no RBCs were returned. Only 144 of 2348 (6.1%) of the comments described procedural or equipment-related events or potential AEs. From these comments two potential AEs were identified: the first was a post-Cesarean section patient who became acutely tachycardic, hypertensive, and dyspneic with rigors. The second was a patient with postpartum hemorrhage who experienced acute dyspnea and hypotension. Both patients were rapidly stabilized and discharged from the hospital shortly thereafter without further complications. It is unclear if these events were caused by ICS reinfusion. No air emboli were reported. The overall rate of patient-related AEs associated with ICS reinfusion was between 0 and 2 per 33,351 (0%-0.006%). CONCLUSIONS: The use of ICS is safe with a very low rate of patient-related AEs.

Electronic enhancements to blood ordering reduce component waste.

BACKGROUND: The effect on component wastage after enhancing the clinician's ability to order blood products in the computerized physician order entry (CPOE) system was investigated in a multihospital network. METHODS: A novel field was added to the CPOE of eight hospitals within a health care system allowing the physician to reserve a red blood cell (RBC) unit for transfusion at a later time. Simultaneously, an electronic means of communication with the blood bank was implemented requiring the nurse to ensure that the patient was prepared for the transfusion before a product could be issued. The wastage rates in the 12 months after these electronic enhancements (Phase 2) was compared to the preceding 19 months of a non-CPOE-based waste reduction campaign (Phase 1) and to the 24 months before the campaign (baseline period). RESULTS: There were significant reductions in platelet (PLT) waste between the baseline period and Phase 1 (p < 0.05) and between Phase 2 and both Phase 1 and the baseline period (p < 0.05). The annual systemwide cost savings in wasted PLTs between the baseline period and Phase 2 was approximately $123,300. RBC waste was significantly reduced between Phase 2 and both Phase 1 and the baseline period (p < 0.05). Cryoprecipitate waste was reduced between Phase 2 and the baseline period (p < 0.05), while plasma waste did not change between the three periods. CONCLUSIONS: Implementing a multifaceted approach to waste reduction led to a significant reduction in wastage for RBCs, PLTs, and cryoprecipitate.

Association of genes with physiological functions by comparative analysis of pooled expression microarray data.

The physiological functions of a tissue in the body are carried out by its complement of expressed genes. Genes that execute a particular function should be more specifically expressed in tissues that perform the function. Given this premise, we mined public microarray expression data to build a database of genes ranked by their specificity of expression in multiple organs. The database permitted the accurate identification of genes and functions known to be specific to individual organs. Next, we used the database to predict transcriptional regulators of brown adipose tissue (BAT) and validated two candidate genes. Based upon hypotheses regarding pathways shared between combinations of BAT or white adipose tissue (WAT) and other organs, we identified genes that met threshold criteria for specific or counterspecific expression in each tissue. By contrasting WAT to the heart and BAT, the two most mitochondria-rich tissues in the body, we discovered a novel function for the transcription factor ESRRG in the induction of BAT genes in white adipocytes. Because the heart and other estrogen-related receptor gamma (ESRRG)-rich tissues do not express BAT markers, we hypothesized that an adipocyte co-regulator acts with ESRRG. By comparing WAT and BAT to the heart, brain, kidney and skeletal muscle, we discovered that an isoform of the transcription factor sterol regulatory element binding transcription factor 1 (SREBF1) induces BAT markers in C2C12 myocytes in the presence of ESRRG. The results demonstrate a straightforward bioinformatic strategy to associate genes with functions. The database upon which the strategy is based is provided so that investigators can perform their own screens.

The tethering arm of the EGF receptor is required for negative cooperativity and signal transduction.

The EGF receptor is a classical receptor-tyrosine kinase. In the absence of ligand, the receptor adopts a closed conformation in which the dimerization arm of subdomain II interacts with the tethering arm in subdomain IV. Following the binding of EGF, the receptor opens to form a symmetric, back-to-back dimer. Although it is clear that the dimerization arm of subdomain II is central to the formation of receptor dimers, the role of the tethering arm of subdomain IV (residues 561-585) in this configuration is not known. Here we use (125)I-EGF binding studies to assess the functional role of the tethering arm in the EGF receptor dimer. Mutation of the three major residues that contribute to tethering (D563A,H566A,K585A-EGF receptor) did not significantly alter either the ligand binding properties or the signaling properties of the EGF receptor. By contrast, breaking the Cys(558)-Cys(567) disulfide bond through double alanine replacements or deleting the loop entirely led to a decrease in the negative cooperativity in EGF binding and was associated with small changes in downstream signaling. Deletion of the Cys(571)-Cys(593) disulfide bond abrogated cooperativity, resulting in a high affinity receptor and increased sensitivity of downstream signaling pathways to EGF. Releasing the Cys(571)-Cys(593) disulfide bond resulted in extreme negative cooperativity, ligand-independent kinase activity, and impaired downstream signaling. These data demonstrate that the tethering arm plays an important role in supporting cooperativity in ligand binding. Because cooperativity implies subunit-subunit interactions, these results also suggest that the tethering arm contributes to intersubunit interactions within the EGF receptor dimer.

Airway Compression During Transcatheter Aortic Valve Replacement via Subclavian Artery Approach: A Case Report.

Transcatheter aortic valve replacement (TAVR) is an alternative to traditional surgery in patients considered to be at high or intermediate risk for open surgical repair of aortic stenosis. Despite its overall safety and efficacy, TAVR is associated with potentially serious complications including major vascular injury. Tracheal compression resulting from vascular pathology has been previously reported; however, airway compromise secondary to vascular injury during TAVR has not been described. We report a case of airway compression and respiratory compromise resulting from injury to the right subclavian artery during TAVR.

Predictors of operating room extubation in adult cardiac surgery.

OBJECTIVE: The primary objective of the study was to identify perioperative factors associated with successful immediate extubation in the operating room after adult cardiac surgery. The secondary objective was to derive a simplified predictive scoring system to guide clinicians in operating room extubation. METHODS: All 1518 patients in this retrospective cohort study underwent standardized fast-track cardiac anesthetic protocol during adult cardiac surgery. Perioperative variables between patients who had successful extubation in the operating room versus in the intensive care unit were retrospectively analyzed using both univariate and multivariable logistic regression analyses. A predictive score of successful operating room extubation was constructed from the multivariable results of 800 patients (derivation set), and the scoring system was further tested using a validation set of 398 patients. RESULTS: Younger age, lower body mass index, higher preoperative serum albumin, absence of chronic lung disease and diabetes, less-invasive surgical approach, isolated coronary bypass surgery, elective surgery, and lower doses of intraoperative intravenous fentanyl were independently associated with higher probability of operating room extubation. The extubation prediction score created in a derivation set of patients performed well in the validation set. Patient scores less than 0 had a minimal probability of successful operating room extubation. Operating room extubation was highly predicted with scores of 5 or greater. CONCLUSIONS: Perioperative factors that are independently associated with successful operating room extubation after adult cardiac operations were identified, and an operating room extubation prediction scoring system was validated. This scoring system may be used to guide safe operating room extubation after cardiac operations.

Self-association of unfolded outer membrane proteins.

We have investigated self-association propensities of aqueous unfolded (U(AQ)) forms of eight outer membrane proteins (OMPs), OmpA, OmpW, OmpX, PagP, OmpT, OmpLa, FadL, and Omp85. We found that high urea concentrations maintain all of these OMPs as monomers and that OmpA and OmpX remain monomeric upon dilution to 1 M urea. A pH screen showed that basic pH supports the least amount of U(AQ) OMP self-association, consistent with earlier studies showing that basic pH was optimal for better folding efficiencies. The addition of KCl increased U(AQ) OMP self-association, although the magnitudes of the responses were varied. These studies showed that urea can be used to tune the amount of U(AQ) OMP self-association and indicate that the presence of some urea may be useful in optimizing folding conditions because it diminishes aggregation.