Diagnostic utility of flow cytometry based coated-platelets assay as a biomarker to predict thrombotic or hemorrhagic phenotype in acute stroke.

BACKGROUND: Coated-platelets are sub-population of platelets "coated" with highly procoagulant proteins and phosphatidylserine that sustains thrombin generation. They are produced upon dual agonist stimulation by collagen and thrombin. This study was conducted to assess if there was any difference in the levels of coated-platelets in patients with primary intracranial hemorrhage (PICH) and ischemic stroke due to large artery atherosclerosis (LAA) as compared to healthy controls, and to see if coated-platelet levels had any influence on the hemorrhagic transformation (HT) of ischemic stroke. METHODS: Coated-platelet levels were determined by flow cytometry using fluorescently tagged Annexin V antibody to identify phosphatidylserine exposed on the surface of platelets activated by dual agonists (convulxin and thrombin) in cross-sectional cohort of 75 patients with stroke and 34 controls. RESULTS: Patients with PICH (n = 35) had significantly lower coated-platelets than the controls (adjusted mean ± SE, 21.0 ± 1.9% vs. 36.1 ± 1.7%, p < 0.001), while patients with LAA (n = 30) had significantly higher coated-platelets than controls (adjusted mean ± SE, 51.9 ± 1.5% vs. 36.1 ± 1.7%, p < 0.001). Patients with subsequent HT of ischemic stroke (n = 10) had significantly lower coated-platelet levels at admission compared to those without HT (adjusted mean ± SE, 18.1 ± 2.6% vs. 51.9 ± 1.5%, p < 0.001). CONCLUSIONS: Coated-platelet levels are significantly different in patients with hemorrhagic and ischemic stroke as compared with controls. Lower levels of coated-platelets measured by flow cytometry may be earliest predictor of subsequent HT in patients with ischemic stroke even before the radiological changes suggestive of HT are visualized.

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.

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.

Predictors of prolonged mechanical ventilation after on-pump coronary artery bypass grafting.

The predictors of prolonged mechanical ventilation and subsequent morbidity after cardiac surgery are ill defined. Our aim was to evaluate them. Four hundred and seventy consecutive patients undergoing coronary artery bypass grafting on cardiopulmonary bypass (CPB) between January and June 2002 were retrospectively analysed for preoperative predictors of prolonged ventilation, which included age, gender, ejection fraction (EF), renal function, diabetes, angina status, severity of the disease (New York Heart Association class), number of vessels diseased and chronic lung disease. Intraoperative variables such as prolonged CPB, aortic cross clamp time, intra-aortic balloon pump (IABP) usage, inotropes and postoperative variables like temperature on arrival at intensive care unit(ICU), IABP usage, organ dysfunction, inotropes and reintervention (reintubation and re-exploration) were also analysed. Prolonged ventilation was defined as > or = 24 hours and these patients were included in group I (n=22). Patients requiring less than 24 hours ventilation (n=448) were included in group II. Stepwise logistic regression analysis was performed. The average age of patients was 56.9 +/- 8.8 years with male predominance (88.4%). The overall perioperative mortality was 2.1% (10 patients) with Group I showing mortality rate of 36.3% (8 patients). In multivariate analysis, predictors of prolonged ventilation were found to be EF <40% (odds ratio, (OR) 13.38), preoperative renal dysfunction [OR 4.06 (serum creatinine > 1.2 mg%)], prolonged CPB, > 120 min (OR 9.6) and reintervention in the form of re-exploration or reintubation in the ICU (OR 13.8). Identification of perioperative variables, which may lead to prolonged ventilation may allow the development of strategies to optimize the patient's condition and ICU management.

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.

Arterial switch operation with in situ coronary reallocation for transposition of great arteries with single coronary artery.

OBJECTIVES: Transposition of great arteries (TGA) with single coronary artery pattern is one of the high-risk groups for arterial switch operation (ASO). Any traction or kinking during coronary transfer can lead to a fatal outcome. With increase in experience, surgical results improved, but it did not completely eliminate the risks of coronary translocation. Many techniques have been described for transfer of single coronary and each one has its own merits and problems. We here in describe a new technique of in situ coronary reallocation during ASO for TGA with single coronary and also report the early and mid-term results with this new technique. METHODS: From September 1988 to June 2002, five consecutive cases of TGA with single coronary artery were operated employing this new technique. Their age ranged from 16 days to 9 months. ASO was done by transecting the great arteries just above the commissures. For coronary reallocation, hockey stick-shaped incisions were made in the facing sinuses of the proximal aorta and the pulmonary artery. These flaps were sutured in such a way that the coronary ostium was committed to the neo-aorta with the rest of surgical procedure done in the usual manner. RESULTS: All five patients had ASO. Additionally, four patients had closure of an associated ventricular septal defect and one patient had repair of the coarctation of the aorta. There was no in hospital mortality. All patients had follow-up echocardiograms at regular intervals, which showed no significant right or left ventricular outflow obstruction, no regional wall motion abnormalities and no neo-aortic or neo-pulmonary regurgitation. Three of five patients had cardiac catheterization and angiocardiography, which showed normal coronary arteries with no obstructive lesions and no neo-aortic regurgitation. Their follow up ranged from 5 to 50 months and there was no late mortality. CONCLUSIONS: This new coronary reallocation technique avoids problems related to coronary translocation such as traction and kinking. It spares the need for dissection of proximal coronary artery and its branches, and thereby eliminates the risk of development of fibrosis and stenosis. The same technique can be used regardless of the sinus of origin of the coronary artery. It is a reliable and a reproducible technique. The early and mid-term results appear excellent in this series.

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.

Heart-lung transplantation in India: initial experience.

Heart-lung transplantation is a well accepted and standard form of therapy for the surgical management of patients with end-stage cardiopulmonary disorders. The first heart-lung transplant in India was performed at our institution on May 3, 1999 and, subsequently, 2 more patients have undergone this procedure. The initial experience is encouraging and heralds a new era of thoracic organ transplantation in India.