Cheong Lim

Prevention of Acute Kidney Injury by Erythropoietin in Patients Undergoing Coronary Artery Bypass Grafting: A Pilot Study

Background/Aims: Depending on the specific definition, acute kidney injury (AKI) occurs in 7–40% of patients undergoing cardiac surgery. Even small changes in serum creatinine (SCr) levels are associated with increased mortality after cardiac surgery. However, there are no current methods for preventing AKI after cardiac surgery. Erythropoietin (EPO) has been shown to elicit tissue-protective effects in various experimental models. In this pilot trial, we evaluated the effectiveness of EPO in the prevention of AKI after coronary artery bypass grafting (CABG). Methods: 71 patients scheduled for elective CABG randomly received either 300 U/kg of EPO or saline intravenously before surgery. AKI was defined as a 50% increase in SCr levels over baseline within the first 5 postoperative days. Estimated glomerular filtration rate (eGFR) was calculated from the Cockcroft-Gault equation. Results: Of 71 patients, 13 developed postoperative AKI: 3 of the 36 patients in the EPO group (8%) and 10 of the 35 patients in the placebo group (29%; p = 0.035). The increase in postoperative SCr concentration and the decline in postoperative eGFR were significantly lower in the EPO group than in the placebo group. Conclusions: In our small, pilot trial, prophylactic administration of EPO prevents AKI and improves postoperative renal function. These data are preliminary and require confirmation in a larger clinical trial.

Off-pump coronary artery bypass may decrease the patency of saphenous vein grafts

BACKGROUNDnThere is concern that a hypercoagulable status is caused after coronary artery bypass grafting without cardiopulmonary bypass (off-pump coronary artery bypass grafting, or OPCAB) and may potentially endanger the patency of the anastomosis. The aims of this study were: (1) to compare 1-year graft patency after OPCAB with that of conventional coronary artery bypass grafting (CABG) and that of on-pump beating CABG; and (2) to demonstrate any differences in patency of various conduits among the three groups.nnnMETHODSnWe analyzed the results of 122 consecutive OPCAB cases (group 1) compared with those of 65 consecutive conventional CABG cases (group II) and those of 19 consecutive on-pump beating CABG cases (group III). In group I, coronary angiography (CAG) was performed immediately postoperatively and 1 year after surgery. In groups II and III, CAG was performed 1 year after surgery. Graft patency was graded as grade A (excellent), grade B (fair), or grade O (occluded).nnnRESULTSnThe average number of distal anastomoses in groups I, II, and III were 3.1 +/- 1.1, 3.7 +/- 0.9, and 3.6 +/- 0.9, respectively. In group I, postoperative CAG was performed in 92% of patients (112/122) before discharge. The patency rate (grade A + B) was 96.4% (162/168) for arterial grafts, and 85.6% (160/187) for saphenous vein grafts (SVG). One-year follow-up CAG was performed in 74% of patients (90/122). The patency rate was 97.8% (132/135) for arterial grafts and 67.9% (106/156) for SVG. In group II, 1-year follow-up CAG was performed in 65% of patients (42/65). The patency rate (grade A + B) was 93.5% (43/46) for arterial grafts and 88.3% (98/111) for SVG. In group III, 1-year follow-up CAG was performed in 89% of patients (17/19). The patency rate (grade A + B) was 100% (19/19) for arterial grafts and 86.8% (33/38) for SVG.nnnCONCLUSIONSnOur results demonstrate that the patency rate ot SVG after OPCAB was significantly lower than that of arterial grafts in the early postoperative CAG (p < 0.001), and was also significantly lower than those of SVG of group II (p < 0.001) and group III (p < 0.01) in the postoperative 1-year CAG, although there was no significant difference in 1-year patency of arterial grafts among the three groups. Our data suggest that a specific perioperative anticoagulant therapy may be advisable in patients undergoing OPCAB with SVG.

Off-pump coronary artery bypass with complete avoidance of aortic manipulation

BACKGROUNDnOff-pump coronary artery bypass (OPCAB) with complete avoidance of aortic manipulation may further reduce perioperative morbidity in addition to the benefits achieved by avoiding cardiopulmonary bypass and cardioplegic arrest.nnnMETHODSnWe prospectively analyzed 222 consecutive patients with multivessel disease who underwent OPCAB without aortic manipulation (group I), and compared them with 123 consecutive patients who underwent OPCAB using additional free arterial or saphenous vein grafts that were anastomosed on the ascending aorta (group II) and 76 consecutive patients who underwent on-pump conventional coronary artery bypass grafting (group III).nnnRESULTSnNo significant differences were noted in operative mortalities among the three groups (2/222, 3/123, and 2/76 in groups I, II, and III, respectively; p = NS). Fewer distal anastomoses were done in group I compared with groups II and III (3.2 +/- 0.9, 3.5 +/- 0.8, and 3.7 +/- 0.9 in groups I, II, and III, respectively; p < 0.001). No differences were noted in the incidences of postoperative morbidities such as mediastinitis, pulmonary complication, and reoperation for bleeding. The incidences of stroke, atrial fibrillation, and acute renal failure were significantly lower in group I than in group III (p < 0.05), although there were no significant differences between groups II and III. The incidence of perioperative myocardial infarction was significantly lower in group I than in groups II and III (p < 0.05), although there was no significant difference between groups II and III.nnnCONCLUSIONSnOur results demonstrate that OPCAB with complete avoidance of aortic manipulation may further reduce the incidence of perioperative morbidities such as stroke, atrial fibrillation, acute renal failure, and perioperative myocardial infarction.

Intraaortic balloon pump therapy facilitates posterior vessel off-pump coronary artery bypass grafting in high-risk patients

BACKGROUNDnDisplacement of the heart to expose posterior vessels during coronary artery bypass grafting (CABG) without cardiopulmonary bypass (off-pump CABG, or OPCAB) may impair cardiac function. We used the intraaortic balloon pump (IABP) preoperatively to reduce operative risk and to facilitate posterior vessel OPCAB in high-risk patients with left main coronary artery disease (> 75% stenosis), intractable resting angina, postinfarction angina, left ventricular dysfunction (ejection fraction < 35%), or unstable angina.nnnMETHODSnOne hundred and forty-two consecutive patients who underwent multivessel OPCAB including posterior vessel revascularization were studied prospectively. The patients were divided into group I (n = 57), which received preoperative or intraoperative IABP, and group II (n = 85), which did not receive IABP. In group I, there were 34 patients with left main coronary artery disease, 24 patients with intractable resting angina, 8 patients with left ventricular dysfunction, 5 patients with postinfarction angina, and 40 patients with unstable angina. Seven patients received intraoperative IABP support owing to hemodynamic instability during OPCAB.nnnRESULTSnThere was no operative mortality in group I and 1 death in group II. The average number of distal anastomoses was not different between group I and group II (3.4 +/- 0.9 versus 3.5 +/- 0.9, p = not significant). There were no significant differences in the number of posterior vessel anastomoses per patient. There were no differences in ventilator support time, length of stay in the intensive care unit, hospital stay, and morbidity between the two groups. There was one IABP-related complication in group I.nnnCONCLUSIONSnIABP therapy facilitates posterior vessel OPCAB in high-risk patients, and surgical results are comparable with those in lower-risk patients.

Bilateral skeletonized internal thoracic artery graftings in off-pump coronary artery bypass: early result of Y versus in situ grafts

BACKGROUNDnUse of bilateral skeletonized internal thoracic arteries (ITAs) in off-pump coronary artery bypass (OPCAB) retains several advantages that may eventually result in better patient outcomes. We compared the early results of OPCAB using bilateral ITAs as Y grafts with results of OPCAB using bilateral ITAs as in situ grafts.nnnMETHODSnA total of 223 consecutive patients who underwent OPCAB using bilateral skeletonized ITAs as Y grafts (group I, n = 113) or in situ grafts (group II, n = 110) were studied.nnnRESULTSnBoth the number of distal anastomoses per patient and the number of distal anastomoses per bilateral ITA were higher in group I (3.5 +/- 1.0 and 2.9 +/- 0.7) than in group II (3.0 +/- 0.7 and 2.4 +/- 0.5) (p < 0.01). Hospital mortality was 1.8% (2/113) in group I and 0.9% (1/110) in group II (p = ns). There were no differences in postoperative complications including atrial fibrillation (13.3% vs 10.9%), perioperative myocardial infarction (0.9% vs 2.7%), mediastinitis (0.9% vs 1.8%), and hypoperfusion syndrome (0.9% vs 0%) between groups I and II (p = ns). Postoperative coronary angiographies performed in 110 patients in group I and 108 patients in group II showed 99.0% (382/386) overall patency and 99.4% (319/321) patency for distal anastomoses using ITAs in group I, and 98.1% (312/318) overall patency and 98.1% (258/263) patency for distal anastomoses using ITA in group II. There were no significant differences in graft patency rates between the two groups (p = ns).nnnCONCLUSIONSnOur results demonstrate that OPCAB using bilateral skeletonized ITAs is technically feasible, with excellent graft patency. Using bilateral skeletonized ITAs as Y grafts increases the number of distal anastomoses that can be performed and does not cause additional postoperative morbidity.

Prediction of fluid responsiveness in mechanically ventilated children undergoing neurosurgery

BACKGROUNDnThe purpose of this study was to evaluate the clinical usefulness of static and dynamic variables for the prediction of fluid responsiveness in children under general anaesthesia.nnnMETHODSnThirty-three mechanically ventilated children received 10 ml kg(-1) colloid for 10 min while stable during surgery. Arterial pressure, heart rate, central venous pressure (CVP), and pleth variability index (PVI), in addition to variation in systolic pressure, pulse pressure (including Δdown and Δup), respiratory aortic blood flow velocity (ΔVpeak), and inferior vena cava diameter were measured before and after volume expansion. Patients were classified as responders to fluid loading if their stroke volume index (SVI) increased by at least 10%.nnnRESULTSnThere were 15 volume responders and 18 non-responders. Of the variables examined, ΔVpeak (r=0.516, P=0.004) and PVI (r=0.49, P=0.004) before volume expansion were significantly correlated with changes in SVI. The receiver-operating characteristic (ROC) curve analysis showed that PVI and ΔVpeak predicted fluid responsiveness. Areas under the ROC curves of PVI and ΔVpeak were statistically larger than that of CVP (P=0.006 and 0.014, respectively). However, those of other variables were similar to that of CVP.nnnCONCLUSIONSnΔVpeak and PVI can be used to predict fluid responsiveness in mechanically ventilated children under general anaesthesia. The other static and dynamic variables assessed in this study were not found to predict fluid responsiveness significantly in children.nnnCLINICAL TRIAL REGISTRATIONnClinicalTrials.gov, NCT01364103.

Comparison of Central Venous Catheterization Sites in Infants

This study aimed to compare the rates of success and complications between different sites of central venous catheterization in infants. A total of 272 infants were randomized to four groups: right subclavian group (G-RSCV), right internal jugular group (G-RIJV), left subclavian group (G-LSCV) and left internal jugular vein group (G-LIJV). In 77.2% of the patients, we successfully introduced a catheter at the first attempt. The rate of successful catheter placement was highest in the RIJV (RIJV 89.7%, LIJV 79.4%, RSCV 66.2% and LSCV 55.9%). With regard to complications, the rate of arterial puncture, guide wire advancement failure and malpositioning of the catheter were all significantly more frequent during SCV catheterization (SCV versus IJV: 10.1% versus 2.1%, 12.4% versus 0% and 13.4% versus 0.6%, respectively). Our results imply that IJV, especially RIJV, should be the first choice for central venous catheterization in infants.

Should we consider the ethnic difference in selecting size of intraaortic balloon by commercial guideline

To evaluate the appropriateness of commercial guideline in selecting the size of balloon for intraaortic counterpulsation in Asian patients, we analyzed the relationship between aortic dimensions measured from computed tomography and body indexes. There were 125 patients who underwent the computed tomography. They were divided into three height groups [<152 cm (I), 152–162 cm (II), and 163–183 cm (III)]. Aortic length and diameter were obtained from the origin of left subclavian artery to the orifice of renal artery. We compared those measurements with the balloon size according to the commercial guideline. Aortic lengths were measured as 250 ± 15 (233–289), 262 ±16 (227–298), and 285 ± 19 (239–334) mm in each group, respectively. As the guideline, if we insert the balloon of 25 ml/191 mm, 34 ml/236 mm, and 40 ml/280 mm, there will be 29 of 66 patients (44%) in group III, who have shorter aortic length, with increased risk of obstructing renal artery. In addition, the younger the patient the higher is the risk (p = 0.038). We should pay attention to proper positioning of intraaortic balloon in younger Asian patients with 163–183 cm height, in applying the commercial guideline to prevent renal arterial obstruction.

Natural history of moderately dilated tubular ascending aorta: implications for determining the optimal imaging interval†

OBJECTIVESnFor a moderately dilated ascending aorta (diameter 35-54u2009mm), current guidelines recommend continuous annual or semi-annual examinations with computed tomography or magnetic resonance imaging. However, few data have shown the yield and benefit of such a protocol. This study aimed to investigate the fate of a moderately dilated ascending aorta and thereby determine the adequate imaging interval.nnnMETHODSnIn our institutional database, we identified adult patients having an ascending aortic diameteru2009≥40u2009mm in contrast-enhanced computed tomography and follow-up imaging(s) afteru2009≥1 year. Of the 509 patients (mean age 67.2u2009±u200910.4 years) enrolled in the study, the maximal diameter of the ascending aorta was compared between the first and last images. Also, their medical records were reviewed to investigate the associated illness and clinical events.nnnRESULTSnThe mean growth rate of the patients with a 40-44u2009mm ( n u2009=u2009321), 45-49u2009mm ( n u2009=u2009142) andu2009≥50u2009mm ( n u2009=u200946) ascending aorta was 0.3u2009±u20090.5, 0.3u2009±u20090.5 and 0.7u2009±u20090.9u2009mm/year, respectively. During the mean interval of 4.3u2009±u20092.4 years, significant progression (diameter increase byu2009≥5u2009mm) occurred in 3.4, 5.6 and 21.7%, respectively. The 3- to 5-year rates of freedom from significant progression were 99.1%-96.5% (40-44u2009mm) and 97.8%-96.4% (45-49u2009mm). In multivariate analysis, initial ascending aortic diameteru2009≥45u2009mm and aortic valve regurgitation were significantly associated with significant progression. Acute type A aortic dissection occurred in 5 patients (1%), before the maximal diameter of the ascending aorta reached 55u2009mm or significant progression was observed.nnnCONCLUSIONSnFor a moderately dilated ascending aorta not exceeding 45u2009mm in maximal diameter and stable in the first annual follow-up image, a 3- to 4-year interval would be reasonable before subsequent imaging. More frequent imaging may be warranted in patients with aortic valve insufficiency or with an aortic diameteru2009≥45u2009mm.

Early Results of Novel Bovine Pericardial Patch Using Comprehensive Anticalcification Procedure in a Swine Model.

We evaluated the short-term safety and effectiveness of our comprehensive anticalcification procedure in swine model. Our comprehensive anticalcification procedure consisted of four steps, including decellularization with sodium dodecyl sulfate and tritonX-100, space filler treatment with polyethylene glycol (PEG), glutaraldehyde cross-linking with organic solvent, and detoxification with glycine. We simultaneously implanted both the commercially available bovine pericardial patch (Supple Peri-Guard) and novel bovine pericardial patch processed by the comprehensive anticalcification procedure into the main pulmonary artery in seven pigs. Every pig underwent a cardiac angiography and was killed on the postoperative day 28. The extracted patches were stained with hematoxylin and eosin. All pigs survived for 4 weeks without any complication. Cardiac angiography showed the absence of leakage and structural problem. Neointimas were formed evenly without intimal hyperplasia. There were no significant differences in the degree of inflammation, necrosis, and calcification between the novel and commercially available patch (p = 0.450, p = 0.317, p = 0.999). Novel bovine pericardial patch using comprehensive anticalcification procedure was similar to existing cardiovascular patch in early surgical results in a swine model. The comprehensive anticalcification procedure could facilitate appropriate bioprosthetic properties of the bovine pericardium.