Ex-vivo canine heart preservation : metabolic studies

The recently developed method of nuclear magnetic resonance spectroscopy allows for continuous monitoring of high energy phosphate compound (ATP and Phosphocreatine) and intracellular pH of tissues or whole organs. In other to better understand why ex-vivo hearts can be preserved for longer periods when perfused with oxygenated crystalloid solutions under hypothermic conditions, two groups of canine hearts were studied with nuclear magnetic resonance spectroscopy.Group 1 = Canine hearts preserved for 4 hours by immersion into a 4$sp circ$C saline solution.Group 2 = Canine hearts preserved for 24 hours by continuous coronary perfusion with a modified oxygenated Krebs solution at 4$sp circ$C.The longer preservation of ATP and phosphocreatine, as well as the slower decrease of intracellular pH in Group II hearts are hypothesized to be the reasons why perfused hearts can be preserved for longer periods of time

Outcomes of post-cardiac surgery patients with persistent hyperlactatemia in the intensive care unit: a matched cohort study

Background: Higher morbidity and mortality rates are seen amongst patients presenting with hyperlactatemia in the postoperative period. The purpose of this study was to determine the relationship between persistent elevations in lactate and poor ICU outcome in post-cardiac surgery patients. Methods: This was a retrospective matched cohort analysis of cardiac surgery patients undergoing bypass and/or valve surgery in a university hospital centre. Selection criteria were: cardiac bypass and/or valve surgery; admission to the ICU for > 24 h postoperatively; and peak lactate ≥ 3.0 mmol/L. Hyperlactatemic patients were matched to 2 normolactatemic patients. Multivariable conditional logistic regression was used to determine predictors of hyperlactatemia and mortality. Results: Four hundred sixty-nine post-cardiac surgery patients were admitted to the ICU for > 24 h. 144 of these patients had an arterial blood lactate ≥ 3.0 mmol/L. Amongst the mortalities, 78.9 % presented with hyperlactatemia. Independent risk factors predictive of a lactate ≥3.0 mmol/L were preoperative IABP insertion (RR 2.8, CI 1.1–7.2) and postoperative acute kidney injury (RR 3.2, CI 2.1–5.4). Patients whose lactate concentrations continued to increase >30 h postoperatively were more likely to die (RR 8.44 CI 2.50–28.53). Conclusions: The persistence of hyperlactatemia is a more important determinant of postoperative outcome than the absolute value of the peak lactate concentration. A simple postoperative lactate washout does not sufficiently explain this lactate accumulation. Mortality is proposed to be secondary to a state of ongoing hypoperfusion.Other UBCNon UBCReviewedFacult

A magician’s tale

Case presentation A 19-year-old male university student and part-time magician presented with a two-week history of fever with rigors, nausea, vomiting, headaches and migrating polyarthralgia. The patient's medical history was significant for a childhood murmur that was presumed benign. The patient denied use of illicit drugs and was not on any medication at the time of presentation. The patient owned several pets, including a dog, a monitor lizard and rabbits used for his magic tricks

Impact of transfusion of mediastinal shed blood on serum levels of cardiac enzymes

Infusion of shed mediastinal blood using an autotransfusion system is a widely applied technique of blood conservation in cardiac surgery. Serial determinations of serum creatine kinase (CK), its MB isoenzyme (CK-MB), and lactate hydrogenase (LDH) levels have been used to monitor perioperative myocardial injury. We investigated the impact of postoperative autotransfused blood infusion on serum levels of these enzymes. We performed a retrospective analysis of postoperative serum CK, CK-MB, and LDH levels of 300 patients who had elective uncomplicated aortocoronary bypass grafting. Shed mediastinal blood samples from 26 patients were analyzed for CK, CK-MB (enzymatic activity and mass), and LDH levels before infusion. High postoperative serum levels of CK and LDH were observed after infusion of autotransfused blood. Shed mediastinal blood contained extremely high levels of these enzymes, particularly from patients who had internal mammary artery dissection. There was a strong correlation (r = 0.96) between measured CK-MB enzyme activities and those calculated from the CK-MB mass units. Infusion of autotransfused blood containing high concentrations of CK and LDH results in elevated serum levels of these enzymes. Hemolysis, frequently present in shed blood, does not interfere with the routine biochemical assays for CK and CK-MB enzyme activities. Caution should be taken when postoperative cardiac enzyme levels are used to determine myocardial injury after aortocoronary bypass grafting if autotransfusion is used as a method of blood conservation

Predictors of Outcomes Following Transcatheter Edge-to-Edge Mitral Valve Repair.

Transcatheter edge-to-edge mitral valve repair is a viable alternative to surgery in patients with severe mitral regurgitation and high surgical risk. Yet the specific group of patients who would optimally benefit from this therapy remains to be determined. Selection of patients for transcatheter strategy is currently based on surgical prognostic scores and technical feasibility. Meanwhile, various clinical, anatomic, and procedural factors have been recently recognized as predictors of adverse outcomes following transcatheter edge-to-edge mitral valve repair, including device failure, recurrent mitral regurgitation, and mortality. Integration of these prognostic factors in the decision-making process of the heart team might improve patient management and outcomes. Herein, the authors review the different factors related to symptomatic status, comorbidity, serum biomarkers, echocardiographic findings, and procedural technique that have been identified as independent predictors of adverse outcome following transcatheter edge-to-edge mitral valve repair and discuss their potential application in everyday clinical practice