Benjamin Ninan

Neutrophil Gelatinase Associated Lipocalin as a Biomarker for Acute Kidney Injury in Patients Undergoing Coronary Artery Bypass Grafting with Cardiopulmonary Bypass

BACKGROUND Acute kidney injury (AKI) is a significant cause of morbidity and mortality following cardiac surgery throughout the world. The paucity of early biomarkers has hampered early therapeutic intervention. Our aim was to evaluate plasma neutrophil gelatinase associated lipocalin (NGAL) levels as a predictor of renal injury in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) along with markers of oxidative stress. METHODS About 30 patients undergoing CABG with CPB were prospectively studied. Blood was collected before bypass, at 4, 12, and 24 hr after CPB initiation, for the analysis of NGAL and oxidative stress markers. RESULTS Eight of 30 patients (26.6%) developed AKI, while 22 (73.4%) did not, as measured by serum creatinine, after 48-72 hr of surgery. However, plasma NGAL levels at 4 hr were high in patients who developed AKI compared with those who did not (352.97 +/- 49.32 vs. 199.83 +/- 23.28 ng/mL, p = 0.000). There was a significant difference in aortic cross-clamp time (p = 0.000), duration of CPB (p = 0.000), and ventilation duration (p < 0.05) between the two groups. The level of malondialdehyde (MDA), a marker of oxidative stress, was higher only at 4 hr in the AKI group. No significant differences were observed in the level of antioxidants between the two groups. A significant correlation was found between plasma NGAL at 4 hr and the change in serum creatinine (r = 0.863, p = 0.006) as well as ventilation duration (r = 0.830, p = 0.011). The sensitivity and specificity of plasma NGAL at 4 hr after CPB was optimal at the 229 ng/mL cut-off with an area under the curve of 0.98 for prediction of AKI. CONCLUSION Measurement of plasma NGAL in patients in the first few hours after CPB is predictive of AKI. Oxidative stress as measured by the level of MDA and antioxidants has no substantial role in the progression of AKI during CABG with CPB.

Effect of N-acetylcysteine in attenuating ischemic reperfusion injury in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.

Ischemic reperfusion injury due to oxidative stress remains one of the challenging problems during cardiac surgeries. The imbalance in the production of free radicals and antioxidants in vivo determines the extent of oxidative stress. The use of antioxidants in cardioplegia has become an important strategy to salvage the myocardium from the attack of these radicals. The objective of this study was to analyze the cardioprotective effect of N-acetylcysteine (NAC) on early reperfusion injury in patients undergoing coronary artery bypass grafting using biochemical markers. Fifty-three patients with left ventricular ejection fraction >0.4 scheduled for coronary artery bypass grafting with cardiopulmonary bypass were selected and divided into two groups. The first group of patients (n=25) received isothermic cardioplegia alone, whereas the second group of patients (n=28) received cardioplegia enriched with NAC (50mg/kg body weight). The free radicals, antioxidants, cardiac troponin I, and hemodynamic and clinical properties of the patients were preoperatively and postoperatively evaluated at five different time intervals. Malondialdehyde level as a measure of free radicals was significantly lower in the NAC-enriched group during reperfusion (p<0.05) and after 12 hr (p<0.05) and 24hr (p<0.001) of surgery. All the antioxidants were elevated in the test group during the reperfusion period (p<0.01). A significant improvement (p=0.001) in the postoperative ejection fraction was noted in the test group. No significant differences were observed between the groups in the level of cardiac troponin I (p=not significant). The use of NAC in patients undergoing coronary artery bypass grafting using cardiopulmonary bypass decreased oxidative stress substantially. However, it did not lead to improvement in the level of cardiac troponin I, a marker of myocardial injury, in our study. Hence, the cardioprotective effect of NAC and the adaptation of the myocardium to oxidative stress should be extensively studied.

Inadvertent placement of left central venous catheter into left internal thoracic vein: a case report.

renal failure requiring institution of renal replacement therapy. All patients were discharged from the hospital. Postoperative mechanical ventilation was less than 24 hours in 27 patients (90%). Postoperative pain control was satisfactory in all patients. The median (interquartile) length of ICU was 1 day (1–4). The median (interquartile) length of hospital stay was 7 days (5–8). To avoid hypotension and inadequate coronary perfusion, the induction of TEA was performed in the operating room, after general anesthesia induction, with the first bolus administered to get the epidural peak effect at the time of skin incision. Epidural hematoma remains the most feared complication of the neuraxial procedures, especially in patients undergoing cardiac surgery. In the present study, the recommendations of the American Society of Regional Anesthesia and Pain Medicine[3] were strictly followed. Pain control was excellent after surgery. In conclusion, TEA can provide a reliable postoperative analgesia, good hemodynamic stability and low rate of intraoperative and postoperative cardiovascular complications in elderly patients undergoing cardiac surgery for primary MR. Further prospective randomized controlled studies are needed to confirm a “therapeutic role” of TEA in this setting.

Arterial switch operation without coronary translocation: mid-term results.

We innovated a technique of arterial switch operation without coronary translocation in 1995, which avoids problems related to coronary artery translocation with good mid-term results. It is a better alternative for surgeons who are not well versed with coronary translocation of conventional arterial switch operation and with difficult coronary anatomy. This report deals with the mid-term results of our new technique.

One-stage repair of cardiac and arch anomalies without circulatory arrest.

Between 1999 and 2002, 23 patients underwent single-stage complete repair of cardiac anomalies and aortic arch obstruction, without circulatory arrest. Median age was 1.2 years. Intracardiac defects included ventricular septal defect in 9, double-outlet right ventricle in 6, d-transposition of the great arteries and ventricular septal defect in 2, subaortic obstruction in 3, and atrial septal defect in 3. Fourteen patients had coarctation of the aorta, 6 had coarctation with hypoplastic aortic arch, and 3 had interrupted aortic arch. Simple techniques were employed such as cannulation of the ascending aorta near the innominate artery and maintaining cerebral and myocardial perfusion. After correction of arch obstruction, intracardiac repair was undertaken. The mean cardiopulmonary bypass time was 169 min, aortic crossclamp time was 51 min, and arch repair took 16 min. There was no operative mortality or neurological deficit. In follow-up of 1–43 months, no patient had residual coarctation. This simplified technique avoids additional procedures, reduces ischemic time, and prevents problems related to circulatory arrest.

Surgical Repair of Interrupted Aortic Arch and Interrupted Pulmonary Artery

Interrupted aortic arch (IAA) is usually associated with ventricular septal defect and patent ductus arteriosus. We report surgical repair in a case of IAA, ventricular septal defect, and interruption of the pulmonary artery with the right pulmonary artery arising from the innominate artery through a separate ductus arteriosus.