Methemoglobin as a marker of acute anemic stress in cardiac surgery.

Biological evidence supports plasma methemoglobin as a biomarker for anemia-induced tissue hypoxia. In this translational planned substudy of the multinational randomized controlled transfusion thresholds in cardiac surgery (TRICS-III) trial, which included adults undergoing cardiac surgery requiring cardiopulmonary bypass with a moderate-to-high risk of death, we investigated the relationship between perioperative hemoglobin concentration (Hb) and methemoglobin; and evaluated its association with postoperative outcomes. The primary endpoint was a composite of death, myocardial infarction, stroke, and severe acute kidney injury at 28 days. We observe weak non-linear associations between decreasing Hb and increasing methemoglobin, which were strongest in magnitude at the post-surgical time point. Increased levels of post-surgical methemoglobin were associated with a trend toward an elevated risk for stroke and exploratory neurological outcomes. Our generalizable study demonstrates post-surgical methemoglobin may be a marker of anemia-induced organ injury/dysfunction, and may have utility for guiding personalized approaches to anemia management. Clinicaltrials.gov registration NCT02042898.

Should Moderate Functional Tricuspid Regurgitation Be Repaired During Surgery for Rheumatic Mitral Valve Disease?

BACKGROUND: Surgical repair of concomitant functional moderate tricuspid valve (TV) regurgitation at the time of mitral valve (MV) surgery remains controversial. AIM: The objective of this study was to evaluate the outcomes of concomitant repair of functional moderate tricuspid regurgitation (TR) during MV surgery for rheumatic valve disease. METHOD: From 1998 to 2016, 1,240 patients had rheumatic MV disease associated with moderate functional TR: 974 patients had MV surgery and concomitant TV repair (group 1) and 266 patients had MV surgery alone (group 2). Study endpoints were operative outcomes, rehospitalisation for congestive heart failure (CHF), and TV reintervention. Propensity score matching identified 192 well-matched pairs for outcomes comparison. RESULTS: Patients who had concomitant TV repair were younger (p=0.02) and there were fewer diabetics (p=0.015). In matched patients, low cardiac output was significantly higher in group 2 (p=0.044) and there was no difference in ventilation time, intensive care unit stay, cardiopulmonary bypass, and ischaemic times (p=0.480, p=0.797, p=0.232, and p=0.550, respectively) between groups. Patients in group 2 required more TV reintervention (1 vs 35 in group 1 and 2, respectively; p=0.004) and rehospitalisation for CHF (5 vs 40 in group 1 and 2, respectively; p<0.001). CONCLUSIONS: Concomitant TV repair for moderate TR in patients undergoing rheumatic MV surgery was not associated with increased operative risk. Postoperative low cardiac output syndrome and the risk of late TV reinterventions and rehospitalisation for CHF were lower with TV repair. Concomitant repair of the moderate TV regurgitation maybe beneficial for patients undergoing rheumatic MV surgery.

Are chest compressions safe for the patient reconstructed with sternal plates? Evaluating the safety of cardiopulmonary resuscitation using a human cadaveric model.

BACKGROUND: Plate and screw fixation is a recent addition to the sternal wound treatment armamentarium. Patients undergoing cardiac and major vascular surgery have a higher risk of postoperative arrest than other elective patients. Those who undergo sternotomy for either cardiac or major vascular procedures are at a higher risk of postoperative arrest. Sternal plate design allows quick access to the mediastinum facilitating open cardiac massage, but chest compressions are the mainstay of re-establishing cardiac output in the event of arrest. The response of sternal plates and the chest wall to compressions when plated has not been studied. The safety of performing this maneuver is unknown. This study intends to demonstrate compressions are safe after sternal plating. METHODS: We investigated the effect of chest compressions on the plated sternum using a human cadaveric model. Cadavers were plated, an arrest was simulated, and an experienced physician performed a simulated resuscitation. Intrathoracic pressure was monitored throughout to ensure the plates encountered an appropriate degree of force. The hardware and viscera were evaluated for failure and trauma respectively. RESULTS: No hardware failure or obvious visceral trauma was observed. Rib fractures beyond the boundaries of the plates were noted but the incidence was comparable to control and to the fracture incidence after resuscitation previously cited in the literature. CONCLUSIONS: From this work we believe chest compressions are safe for the patient with sternal plates when proper plating technique is used. We advocate the use of this life-saving maneuver as part of an ACLS resuscitation in the event of an arrest for rapidly re-establishing circulation.

Impact of clopidogrel use on mortality and major bleeding in patients undergoing coronary artery bypass surgery.

Patients who received clopidogrel prior to coronary bypass surgery are at increased risk for bleeding that must be balanced with risk of ongoing ischemia if coronary artery bypass grafting is delayed. This study aimed to evaluate the impact of clopidogrel on mortality and major bleeding in patients undergoing urgent coronary bypass surgery. We reviewed 451 consecutive patients who underwent urgent isolated coronary bypass surgery; 262 had not received clopidogrel, whereas 189 received clopidogrel < or = 5 days preoperative. The primary endpoint was in-hospital death, massive transfusion or massive blood loss. Patient characteristics were almost similar between groups. There was no difference in in-hospital death or massive bleeding indices between groups (clopidogrel: 7% vs. no clopidogrel: 6%, P = 0.9). No difference was observed even after adjusting for the date of stopping clopidogrel preoperatively. Multivariate regression analysis showed that clopidogrel or the duration it was stopped preoperatively, did not predict adverse outcomes. Significant independent predictors included preoperative renal dysfunction, hemoglobin level and peripheral vascular disease. clopidogrel, or the time it was stopped prior to surgery, was not a risk factor for in-hospital death, massive bleeding, or other poor early outcomes in patients undergoing urgent coronary artery bypass surgery.

Predictors of packed red cell transfusion after isolated primary coronary artery bypass grafting--the experience of a single cardiac center: a prospective observational study.

BACKGROUND: Preoperative patients' characteristics can predict the need for perioperative blood component transfusion in cardiac surgical operations. The aim of this prospective observational study is to identify perioperative patient characteristics predicting the need for allogeneic packed red blood cell (PRBC) transfusion in isolated primary coronary artery bypass grafting (CABG) operations. PATIENTS AND METHODS: 105 patients undergoing isolated, first-time CABG were reviewed for their preoperative variables and followed for intraoperative and postoperative data. Patients were 97 males and 8 females, with mean age 58.28 +/- 10.97 years. Regression logistic analysis was used for identifying the strongest perioperative predictors of PRBC transfusion. RESULTS: PRBC transfusion was used in 71 patients (67.6%); 35 patients (33.3%) needed > 2 units and 14 (13.3%) of these needed > 4 units. Univariate analysis identified female gender, age > 65 years, body weight < or = 70 Kg, BSA < or = 1.75 m(2), BMI < or = 25, preoperative hemoglobin < or = 13 gm/dL, preoperative hematocrit < or = 40%, serum creatinine > 100 micromol/L, Euro SCORE (standard/logistic) > 2, use of CPB, radial artery use, higher number of distal anastomoses, and postoperative chest tube drainage > 1000 mL as significant predictors. The strongest predictors using multivariate analysis were CPB use, hematocrit, body weight, and serum creatinine. CONCLUSION: The predictors of PRBC transfusion after primary isolated CABG are use of CPB, hematocrit < or = 40%, weight < or = 70 Kg, and serum creatinine > 100 micromol/L. This leads to better utilization of blood bank resources and cost-efficient targeted use of expensive blood conservation modalities.

Harvesting of the radial artery for coronary artery bypass grafting: comparison of ultrasonic harmonic scalpel dissector with the conventional technique.

OBJECTIVES: Use of the radial artery for coronary artery bypass grafting is getting more popular. We started routine use of the ultrasonic dissecting scalpel in harvesting radial arteries aiming to minimize harvesting time, improve graft quality, and reduce wound complications. METHODS: Radial artery harvesting technique using harmonic scalpel (HS; 43 patients) was compared with the conventional technique (Hemostatic clips and scissors; 53 patients). To avoid spasm, the radial artery was not skeletonized and papaverine was used to irrigate radial artery routinely in all patients. RESULTS: Compared to the conventional technique, radial artery harvesting using the HS has a significantly shorter harvesting time (25 minutes vs. 50 minutes, p < 0.001) and required a significantly smaller number of hemostatic clips (3 vs. 40, p < 0.001). In situ free blood flow was significantly higher in HS group (80 mL/min vs. 40 mL/min, p < 0.001). There was no forearm wound infection in the HS group. There was no graft failure, reoperation for bleeding, or hand ischemia with the use of either technique. CONCLUSION: Harvesting the radial artery using the HS is less time consuming and decreased the use of hemostatic clips rather atraumatic with good quality graft.