Dae-Kee Choi

Does remote ischaemic preconditioning with postconditioning improve clinical outcomes of patients undergoing cardiac surgery? Remote Ischaemic Preconditioning with Postconditioning Outcome Trial

AIMS The aim of this study was to evaluate whether remote ischaemic preconditioning (RIPC) combined with remote ischaemic postconditioning (RIPostC) improves the clinical outcomes of patients undergoing cardiac surgery. METHODS AND RESULTS From June 2009 to November 2010, 1280 patients who underwent elective cardiac surgery were randomized into the RIPC with RIPostC group or the control group in the morning of the surgery. In the RIPC with RIPostC group, four cycles of 5-min ischaemia and 5-min reperfusion were administered twice to the upper limb-before cardiopulmonary bypass (CPB) or coronary anastomoses for RIPC and after CPB or coronary anastomoses for RIPostC. The primary endpoint was the composite of major adverse outcomes, including death, myocardial infarction, arrhythmia, stroke, coma, renal failure or dysfunction, respiratory failure, cardiogenic shock, gastrointestinal complication, and multiorgan failure. Remote ischaemic preconditioning with RIPostC did not reduce the composite outcome compared with the control group (38.0 vs. 38.1%, respectively; P = 0.998) and there was no difference in each major adverse outcome. The intensive care unit and hospital stays were not different between the two groups. However, in the off-pump coronary artery bypass surgery subgroup, multivariate logistic regression analysis revealed that RIPC with RIPostC was related to increased composite outcome (odds ratio: 1.54; 95% confidence interval: 1.02-2.30; P = 0.038). CONCLUSION Remote ischaemic preconditioning with RIPostC by transient upper limb ischaemia did not improve clinical outcome in patients who underwent cardiac surgery.

Effect of Exogenous Albumin on the Incidence of Postoperative Acute Kidney Injury in Patients Undergoing Off-pump Coronary Artery Bypass Surgery with a Preoperative Albumin Level of Less Than 4.0 g/dl.

Background:Hypoalbuminemia may increase the risk of acute kidney injury (AKI). The authors investigated whether the immediate preoperative administration of 20% albumin solution affects the incidence of AKI after off-pump coronary artery bypass surgery. Methods:In this prospective, single-center, randomized, parallel-arm double-blind trial, 220 patients with preoperative serum albumin levels less than 4.0 g/dl were administered 100, 200, or 300 ml of 20% human albumin according to the preoperative serum albumin level (3.5 to 3.9, 3.0 to 3.4, or less than 3.0 g/dl, respectively) or with an equal volume of saline before surgery. The primary outcome measure was AKI incidence after surgery. Postoperative AKI was defined by maximal AKI Network criteria based on creatinine changes. Results:Patient characteristics and perioperative data except urine output during surgery were similar between the two groups studied, the albumin group and the control group. Urine output (median [interquartile range]) during surgery was higher in the albumin group (550 ml [315 to 980]) than in the control group (370 ml [230 to 670]; P = 0.006). The incidence of postoperative AKI in the albumin group was lower than that in the control group (14 [13.7%] vs. 26 [25.7%]; P = 0.048). There were no significant between-group differences in severe AKI, including renal replacement therapy, 30-day mortality, and other clinical outcomes. There were no significant adverse events. Conclusion:Administration of 20% exogenous albumin immediately before surgery increases urine output during surgery and reduces the risk of AKI after off-pump coronary artery bypass surgery in patients with a preoperative serum albumin level of less than 4.0 g/dl.

Prognostic implications of preoperative E/e' ratio in patients with off-pump coronary artery surgery.

Background: The ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/e′) correlates with left ventricular (LV) filling pressure. In particular, an E/e′ ratio more than 15 is an excellent predictor of increased LV filling pressure. The authors evaluated the prognostic implications of preoperative estimated LV filling pressure, assessed by E/e′ ratio, in patients undergoing off-pump coronary artery bypass graft surgery. Methods: This observational study investigated 1,048 consecutive adults undergoing elective off-pump coronary artery bypass graft surgery. The primary outcome was occurrence of major adverse cardiac events (MACE), defined as a composite of death, myocardial infarction, malignant ventricular arrhythmia, cardiac dysfunction, or need for new revascularization. Logistic regression and survival analyses were performed. Results: An E/e′ ratio more than 15 was independently associated with 30-day MACE (odds ratio 2.4, 95% CI 1.4–3.9, P = 0.001) and 1-yr MACE (hazard ratio 2.1, 95% CI 1.4–3.1, P = 0.001), irrespective of underlying LV ejection fraction. MACE free 1-yr survival rate was significantly decreased in patients with E/e′ >15, irrespective of underlying LV ejection fraction. Conclusions: Increased LV filling pressure, assessed by E/e′ ratio, is an independent predictor of 30-day and 1-yr MACE in patients who undergo elective off-pump coronary artery bypass graft surgery. These findings indicate that measurements of E/e′ may assist in preoperative risk stratification of these patients.

Association of Preoperative Uric Acid and Acute Kidney Injury Following Cardiovascular Surgery

OBJECTIVE Recent studies suggested that elevated serum uric acid levels may be associated with the risk of acute kidney injury (AKI) in several settings. However, the effect of uric acid on the risk of AKI after cardiovascular surgery remains uncertain. DESIGN A retrospective analysis. SETTING A tertiary care university hospital. PARTICIPANTS All consecutive adult patients (n = 1,019) who underwent cardiovascular surgery between January 2011 and May 2012. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Preoperative and perioperative data were assessed in the study population. AKI was defined and staged as serum creatinine concentration-based Acute Kidney Injury Network criteria. Univariate and multivariate logistic regression analyses were conducted to evaluate the association between preoperative uric acid and postoperative AKI. Preoperative elevated uric acid (≥ 6.5 mg/dL) was associated independently with AKI after cardiovascular surgery (odds ratio 1.46; 95% confidence interval 1.04-2.06, p = 0.030). Results were the same in subgroup analyses. Preoperative elevated uric acid (≥ 6.5 mg/dL) also was associated with a higher incidence of prolonged ICU and hospital stay. CONCLUSIONS Preoperative elevated serum uric acid is an independent risk factor for AKI in patients undergoing cardiovascular surgery. This finding suggests that preoperative measurements of serum uric acid concentration may help stratify risks for AKI in these patients.

Risk Factors of Postoperative Acute Kidney Injury in Patients Undergoing Esophageal Cancer Surgery

OBJECTIVE The purpose of this study was to identify perioperative risk factors for postoperative acute kidney injury (AKI) in patients undergoing esophageal cancer surgery. DESIGN A retrospective analysis of the prospectively collected medical data. SETTING A tertiary care university hospital. PARTICIPANTS All consecutive adult patients (n=595) who underwent elective esophageal surgery for cancer between January 2005 and April 2012. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS AKI was defined by the AKI Network criteria based on serum creatinine changes within the first 48 hours after esophageal cancer surgery. The relationship between perioperative variables and AKI was evaluated using multivariate logistic regression. Postoperative AKI developed in 210 (35.3%) patients. Risk factors for AKI were body mass index (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.01-1.14), preoperative serum albumin level (OR 0.52; 95% CI 0.33-0.84), use of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers (OR 1.35; 95% CI 1.05-1.75), colloid infusion during surgery (OR 1.11; 95% CI 1.06-1.18), and postoperative 2-day C-reactive protein (OR 1.05; 95% CI 1.01-1.09). Postoperative AKI was associated with prolonged length of hospital stay. CONCLUSIONS Postoperative AKI is common in patients undergoing esophageal surgery for cancer. Closer evaluation and monitoring in patients with risk factors for AKI may be warranted.

Postoperative Hypoalbuminemia Is Associated With Outcome in Patients Undergoing Off-Pump Coronary Artery Bypass Graft Surgery

OBJECTIVE The authors aimed to investigate whether immediate postoperative hypoalbuminemia could be associated with outcomes after off-pump coronary artery bypass graft (OPCAB) surgery. DESIGN A retrospective analysis of the medical data. SETTING Cardiac operating room and adult cardiovascular intensive care unit at a single institution. PARTICIPANTS Six hundred ninety adult patients underwent elective OPCAB surgery over a 30-month period. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS To evaluate the clinical relevance of immediate postoperative hypoalbuminemia, the lowest serum albumin level measured over the first 12 hours postoperatively was recorded. A cutoff point was calculated by the area under the curve in the receiver operating characteristic plot for 30-day adverse events including death. Patients were classified according to the cutoff value, and outcomes were compared between groups using propensity score-matching analysis. The impact of immediate postoperative hypoalbuminemia on OPCAB outcome was investigated using multivariate analysis. The cutoff value for immediate postoperative albumin concentration for predicting 30-day adverse events was 2.3 g/dL. Immediate postoperative hypoalbuminemia (<2.3 g/dL) was associated independently with postoperative respiratory failure (odds ratio [OR] = 8.85, p = 0.04), wound infection (OR = 4.44, p = 0.04), the need for an intra-aortic balloon pump after the operation (OR = 13.7, p = 0.02), renal failure (OR = 7.98, p = 0.01), reoperation for bleeding (OR = 4.33, p = 0.05), and the need for inotropes in the intensive care unit (OR = 1.79, p = 0.02). CONCLUSIONS Immediate postoperative hypoalbuminemia was associated with poorer outcomes in OPCAB patients. Monitoring of albumin levels after OPCAB could identify patients at risk for short-term adverse events.

Intraoperative Renal Regional Oxygen Desaturation Can Be a Predictor for Acute Kidney Injury after Cardiac Surgery

OBJECTIVE To evaluate the usefulness of renal regional oxygen saturation (renal rSO2) in predicting the risk of acute kidney injury (AKI) after cardiac surgery. DESIGN A prospective observational study. SETTING Tertiary care university hospital. PARTICIPANTS One hundred patients undergoing cardiac surgery. INTERVENTIONS Renal rSO2 was monitored continuously by near-infrared spectroscopy (NIRS) throughout the anesthetic period. MEASUREMENTS AND MAIN RESULTS Postoperative AKI was defined using the Risk, Injury, Failure, Loss, and End-stage (RIFLE) criteria. Of 95 patients who were included in the final analysis, 34 patients developed AKI after surgery. Recorded renal rSO2 data were used to calculate the total duration of the time when renal rSO2 was below the threshold values of 70%, 65%, 60%, 55%, and 50%. The total periods when the renal rSO2 level was below each of the threshold values were significantly longer in patients with AKI than in those without AKI (p = 0.001 or p<0.001). Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive power of renal rSO2 for AKI. The ROC curve analysis showed that renal rSO2 could predict the risk of AKI with statistical significance and that a renal rSO2<55% had the best performance (area under the curve-ROC, 0.777; 95% CI, 0.669-0.885; p<0.001). Multivariate logistic regression analysis revealed that AKI significantly correlated with the duration of renal rSO2<55% (p = 0.002) and logistic EuroSCORE (p = 0.007). CONCLUSIONS Intraoperative renal regional oxygen desaturation can be a good predictor of AKI in adult patients undergoing cardiac surgery.

The analgesic efficacy and safety of nefopam in patient-controlled analgesia after cardiac surgery: A randomized, double-blind, prospective study

Objective The efficacy and side-effects of nefopam were prospectively compared with those of fentanyl for patient-controlled analgesia (PCA) following cardiac surgery. Methods Patients scheduled to undergo cardiac surgery were randomly assigned between three PCA groups (nefopam, fentanyl or nefopam + fentanyl). Pain was assessed at rest and during movement at 12, 24, 36, 48 and 72 h after surgery using a visual analogue scale (VAS). Total infused PCA volume, number of rescue drug injections, duration of intubation and length of stay in the intensive care unit were recorded. The incidence of adverse effects was noted at 48 h postoperatively. Results There were no significant between-group differences in VAS score, total PCA infusion volume or number of rescue injections (n = 92 per group). Nausea was significantly more common in the fentanyl group compared with both other groups. Conclusions PCA with nefopam alone provides suitable postoperative analgesia after cardiac surgery.

Impact of intravenous lidocaine on myocardial injury after off-pump coronary artery surgery

BACKGROUND Lidocaine has been demonstrated to exert cardioprotective effects against myocardial ischaemia and reperfusion injury. We evaluated whether a continuous i.v. infusion of lidocaine reduced myocardial injury in patients undergoing off-pump coronary artery bypass graft surgery (OPCAB). METHODS In this randomized, double-blinded trial, 99 patients received i.v. lidocaine 2% (i.e. a 1.5 mg kg(-1) bolus at induction of anaesthesia followed by a 2.0 mg kg(-1) h(-1) infusion intraoperatively) or an equal volume of saline. Serum creatine kinase-myocardial band (CK-MB) and troponin I (TnI) concentrations were measured before surgery, upon arrival in the intensive care unit, and at 6, 24, 48, and 72 h after surgery. Cardiac enzymes, other biological markers, and rate of postoperative adverse events were compared between the groups. RESULTS The median (25-75% inter-quartile range) TnI [0.90 (0.43-1.81) vs 1.71 (0.88-3.02) ng ml(-1), P=0.027] and CK-MB [6.5 (3.9-12.3) vs 9.8 (6.0-18.6) ng ml(-1), P=0.005] concentrations 24 h after surgery were significantly lower in the lidocaine group than in the control group. Moreover, lidocaine infusion reduced the total area under the curve of TnI and CK-MB release after surgery by 42% and 27%, respectively, compared with control. CONCLUSIONS Continuous i.v. infusion of lidocaine during surgery reduces myocardial injury in patients undergoing OPCAB.

Effect of remote ischemic preconditioning on cognitive function after off-pump coronary artery bypass graft: a pilot study

Background Several studies have shown in animal models that remote ischemic preconditioning (rIPC) has a neuroprotective effect. However, a randomized controlled trial in human subjects to investigate the neuroprotective effect of rIPC after cardiac surgery has not yet been reported. Therefore, we performed this pilot study to determine whether rIPC reduced the occurrence of postoperative cognitive dysfunction in patients who underwent off-pump coronary artery bypass graft (OPCAB) surgery. Methods Seventy patients who underwent OPCAB surgery were assigned to either the control or the rIPC group using a computer-generated randomization table. The application of rIPC consisted of four cycles of 5 min ischemia and 5 min reperfusion on an upper limb using a blood pressure cuff inflating 200 mmHg before coronary artery anastomosis. The cognitive function tests were performed one day before surgery and again on postoperative day 7. We defined postoperative cognitive dysfunction as decreased postoperative test values more than 20% of the baseline values in more than two of the six cognitive function tests that were performed. Results In the cognitive function tests, there were no significant differences in the results obtained during the preoperative and postoperative periods for all tests and there were no mean differences observed in the preoperative and postoperative scores. The incidences of postoperative cognitive dysfunction in the control and rIPC groups were 28.6% (10 patients) and 31.4% (11 patients), respectively. Conclusions rIPC did not reduce the incidence of postoperative cognitive dysfunction after OPCAB surgery during the immediate postoperative period.