Shiv Kumar Choudhary

Pulmonary autograft: Should it be used in young patients with rheumatic disease?

BACKGROUND Although pulmonary autograft is being increasingly used to replace the diseased aortic valve with excellent long-term results, its use in the population with rheumatic disease still needs careful evaluation. PATIENTS AND METHODS From October 1993 through March 1998, 102 patients underwent aortic valve replacement with a pulmonary autograft (Ross procedure). The mean age was 27.9 +/- 4.2 years (range, 0.8-56 years). The cause was rheumatic disease in 75 patients (73%), bicuspid aortic valve in 26 patients (26%), and myxomatous aortoarteritis in 1 patient (1%). The root replacement technique was used in all. In addition, 31 patients had 33 associated procedures: mitral valve repair (n = 15 patients), open mitral commissurotomy (n = 15 patients), tricuspid repair (n = 2 patients), and homograft mitral valve replacement (n = 1 patient). RESULTS Operative mortality was 6.9% (7 patients). Late mortality was 7.8% (8 patients). Follow-up ranged from 1 to 60 months (mean, 25.3 +/- 15.4 months) and was 98% complete. Two patients required reoperation for failed mitral valve repair, and 2 other patients underwent reoperation for failure of both the autograft and mitral valve repair. Echocardiographic assessment showed moderate to severe aortic regurgitation in 13 patients, along with thickening of the autograft. All of these patients had rheumatic disease and were young (<30 years). Ten of these patients had undergone associated mitral valve procedure. Morphologic and histopathologic examination of explanted autografts showed features compatible with rheumatic valvulitis. CONCLUSION Pulmonary autograft is susceptible to rheumatic involvement. Young age (<30 years) and associated mitral valve disease are significant risk factors for autograft failure in patients with rheumatic disease. Use of pulmonary autograft in this subgroup of patients requires a cautious approach.

Comparison of Epsilon Aminocaproic Acid and Tranexamic Acid in Thoracic Aortic Surgery: Clinical Efficacy and Safety

OBJECTIVE To evaluate the efficacy and safety of tranexamic acid (TXA) versus epsilon aminocaproic acid (EACA) in patients undergoing thoracic aortic surgery. DESIGN A prospective randomized study. SETTING A tertiary care center. PARTICIPANT The study was conducted on 64 consecutive adult patients undergoing thoracic aortic surgery with cardiopulmonary bypass (CPB). INTERVENTIONS Group EACA received a bolus of 50 mg/kg of EACA after induction of anesthesia over 20 minutes followed by maintenance infusion of 25 mg/kg/h until chest closure. Group TXA received a bolus of 10 mg/kg of TXA after induction of anesthesia over 20 minutes followed by maintenance infusion of 1 mg/kg/h until chest closure. MEASUREMENTS AND MAIN RESULTS Cumulated mean blood loss, total packed red blood cells, and blood product requirement up to 24 h postoperatively were comparable between groups. A significant renal injury (EACA 40% v TXA 16%; p = 0.04) and increased tendency for renal failure (EACA 10% v TXA 0%, p = 0.11; relative risk 2.15) were observed with EACA compared to TXA. There was increased tendency of seizure with TXA (EACA v TXA: 3.3% v 10%; p>0.05, relative risk 1.53). There was significant increase in the D-dimer from preoperative to postoperative values in Group EACA. (p< 0.01). CONCLUSIONS Both EACA and TXA were equally effective in reducing the perioperative blood loss and transfusion requirement in patients undergoing thoracic aortic surgery. While significant renal injury was observed with EACA, there was a tendency for higher incidence of seizure with TXA. Prospective placebo-controlled trials recruiting larger sample size using sensitive biomarkers are required before any recommendations.

Reducing the costs of surgical correction of congenitally malformed hearts in developing countries.

A large number of patients in developing countries require surgical correction of congenitally malformed hearts. Unfortunately, only a limited number of centres offer these patients surgery at an affordable cost. In this review, we discuss the problems in managing these patients, with an emphasis on reduction of costs, so that the maximum number of patients can benefit. It is apparent that containing costs requires a multipronged approach, which begins with timely referral, and continues with early surgical correction and adequate postoperative care carried out in a scientific manner. Indigenization, innovation, training of manpower, and building a team, are essential to cut the costs, and to improve the quality of care.

Atrial switch operation in the current era: modifications and pitfalls.

Although rarely performed today, atrial switch operations continue to have an important role in the management of some forms of congenital heart disease. In developing countries, delayed diagnosis and presentation of patients with transposition of the great arteries is not uncommon. For some patients who are referred for surgery beyond the newborn period, the atrial switch operations are still considered to be the best option. Also, as part of surgical repair of congenitally corrected transposition, an atrial switch operation is combined with arterial switch or the Rastelli procedure as an alternative to physiologic repair. In isolated ventricular inversion (atrioventricular discordance with ventriculoarterial concordance), the atrial switch operation alone leads to complete anatomical correction. Finally, management of late complications of atrial switch operations requires a thorough understanding of the procedures.

Development of indices for quantification of nozzle clogging during continuous slab casting

Abstract Deposition of alumina inclusions inside the submerge entry nozzle is a long standing problem in continuous casting of aluminium killed steel. Clogging of the casting nozzle severely affects productivity and also causes degradation of product quality. Unfortunately, very few numerical tools are available for precise quantification of the magnitude of clogging. Tools for quantifying the extent of clogging were developed during the present work and have been integrated with the control system of a running continuous slab casting shop. Reasonable match has been observed between the estimation from the developed program and the actual observations in the casting shop and subsequent products. In addition to process control, the tools were also found useful for comparing the castability of different steel grades. This feature has been utilised to study nozzle clogging during casting of steel grades that are commonly believed to have poor castability.

Arterial Switch Operation With Unidirectional Valved Patch Closure of Ventricular Septal Defect in Patients With Transposition of Great Arteries and Severe Pulmonary Hypertension

Objective: For patients with dextro-transposition of great arteries (d-TGAs), ventricular septal defect (VSD), and severe pulmonary arterial hypertension (PAH), the common surgical options are palliative arterial switch operation (ASO) or palliative atrial switch operation leaving the VSD open. We evaluated the role of ASO with VSD closure using a fenestrated unidirectional valved patch (UVP). Methods: Between July 2009 and February 2011, six patients with TGAs, VSD, and severe PAH (mean age 39.8 ± 47.4 months, median 21, range 8-132 months), weighing 10.7 ± 9.2 kg (median 8.6, range 4.3-29 kg), underwent ASO with VSD closure using our simple technique of UVP. Mean pulmonary artery systolic pressure before the operation was 106 ± 12.7 mm Hg (median 107.5, range 95-126 mm Hg) and pulmonary vascular resistance was 9.5 ± 4.22 units (median 9.5, range 6.6-17.1 Wood units). Results: There were no deaths. All patients had a postoperative systemic arterial saturation of more than 95%, although there were frequent episodes of systemic desaturation due to right-to-left shunt across the valved VSD patch (as seen on transesophageal and transthoracic echocardiograms). Mean follow-up was 10 ± 7.6 months (median 7.5, range 1-22 months). At most recent follow-up, all patients had systemic arterial saturation of more than 95% and no right-to-left shunt through the VSD patch. In one patient, the follow-up cardiac catheterization showed a fall in pulmonary artery systolic pressure to 49 mm Hg. Conclusion: Arterial switch operation with UVP VSD closure is feasible with acceptable early results. It avoids complications of palliative atrial switch (arrhythmia and baffle obstruction) and partially or completely open VSD.

Thermodynamic Evaluation of Inclusion Formation during Cooling and Solidification of Low Carbon Si-Mn Killed Steel

The primary endogenous inclusions are inherent and specific to the deoxidation process and may contribute significantly to the steel properties besides affecting its castability during continuous casting. Additional (secondary) inclusions form during cooling and subsequent freezing of liquid steel during continuous casting operation. Therefore, in order to produce clean steel it is extremely important to understand clearly their formation mechanisms. Rejection of solutes by the solidifying dendrites causes segregation of solutes in the interdendritic liquid with consequent build-up of their thermodynamic super saturation. Rejected solute elements subsequently react to give rise to secondary inclusions in the solidifying liquid steel. The present investigation aimed at development of an appropriate thermodynamic calculation procedure for the prediction of inclusion compositions formed during cooling and solidification of liquid steel. The model has been applied to an inclusion sensitive grade of steel. Segregation of various solutes with progress of freezing was calculated using the Clyne–Kurz microsegregation equation. A sequential computation procedure involving segregation equation and thermodynamic equilibrium calculations by the Factsage-06 thermodynamic software was developed. Compositions of inclusions at various stages of solidification were calculated. Model predictions were finally compared with literature as well as with observed inclusion compositions determined in several continuously cast billet samples using SEM-EDS. Reasonably good correspondence between model predictions and observed inclusions have been obtained. The model has provided deeper insight into the formation mechanisms of various nonmetallic inclusions in steel and provided the required guidance for controlling them.

Cardiopulmonary Bypass and Serum Thyroid Hormone Profile in Pediatric Patients with Congenital Heart Disease

OBJECTIVE To study the effect of cardiopulmonary bypass (CPB) on serum thyroid hormone profile in children undergoing open-heart surgery. DESIGN Prospective cross-sectional study. SETTING Multispecialty tertiary level referral center. PATIENTS One hundred consecutive patients (age 15.9 ± 14.6 months, weight 6.7 ± 2.5 kg) undergoing open-heart surgery under CPB. INTERVENTIONS None. OUTCOME MEASURES Levels and trends of serum total thyroxine (TT4), free thyroxine (FT4), total tri-iodothyronine (TT3), free tri-iodothyronine (FT3) and thyroid stimulating hormone (TSH), survival, inotropic score, duration of mechanical ventilation, postoperative complications. RESULTS TT4 levels were 9.08 ± 3.6, 6.4 ± 2.5, 6.24 ± 2.1, 6.43 ± 2.4, 7.20 ± 3.0 µg/dL at baseline and at 1, 24, 48 and 72 hours; FT4 levels were 1.82 ± 0.5, 1.49 ± 0.3, 1.29 ± 0.3, 1.32 ± 0.4, and 1.43 ± 0.5 ng/dL; TT3 levels were 1.81 ± 0.4, 1.31 ± 0.3, 0.99 ± 0.2, 1.0 ± 0.37, and 1.17 ± 0.48 ng/ml; FT3 levels were 4.09 ± 1.0, 3.02 ± 0.8, 2.21 ± 0.6, 2.22 ± 0.7, and 2.66 ± 1.05 pg/ml; TSH levels were 5.40 ± 3.8, 2.0 ± 3.1, 1.24 ± 1.1, 2.90 ± 3.3, and 4.03 ± 3.4 mIU/L. There was significant fall (29.1% for FT4, 32.1% for TT4, 77% for TSH, 46% for FT3 and 45% for TT3, p < 0.0001). When area under curve (AUC) TT4 was compared between survivors (n = 87) and nonsurvivors (n = 12), significantly larger AUC was seen in survivors (492.81 ± 158.6) than nonsurvivors (360.75 ± 179.6 p = 0.0125). In survivors >72 hours, AUC TT4 was larger in patients with uneventful postoperative course versus those with postoperative complications (516.48 ± 18.6 vs. 394.78 ± 29.9, p = 0.001). AUC TT4 showed significant inverse correlation with inotropic score and borderline inverse correlation with duration of mechanical ventilation. CONCLUSION Children undergoing surgery under CPB showed significant fall in thyroid hormones. Because TT4 level is modifiable, prophylactic administration of TT4 for improving outcomes needs to be studied further.

Application of Stem Cell Technology for Coronary Artery Disease at the All India Institute of Medical Sciences, New Delhi, India

Stem cell technology is rapidly gaining popularity as a way to improve the prognosis of patients with coronary artery disease and heart failure. In this review, we systematically analyze the basis, methods, and results of stem cell technology for coronary artery disease at the All India Institute of Medical Sciences, New Delhi, India.

Outcomes of Patients Undergoing Primary Fontan Operation Beyond First Decade of Life

Objectives: Studies on older patients undergoing primary Fontan operation (FO) are limited, with conflicting results. We review our experience with these patients beyond the first decade of life. Patients and Methods: Between January 2000 and December 2014, a total of 105 patients ≥10 years of age (mean 15.6 ± 4.9, range 10-31, median 15 years) underwent primary FO without a prior bidirectional superior cavopulmonary anastomosis (Bidirectional Glenn [BDG]). Mean preoperative New York Heart Association (NYHA) class was 2.2 ± 0.57. Results: Operative procedure was extra-cardiac FO in 62 patients (8 were fenestrated). Forty-three had a lateral tunnel FO (26 were fenestrated). There were 11 (10.5%) early deaths. Fourteen of the 94 early survivors experienced prolonged pleural effusions, 7 had arrhythmias, and 2 had thromboembolic events. Two patients underwent Fontan takedown. On univariate analysis, NYHA functional class III, mean pulmonary artery (PA) pressure ≥15 mm Hg, hematocrit ≥60%, preoperative ventricular dysfunction, and atrioventricular valve regurgitation (AVVR) were associated with early mortality. Median follow-up was 78 (mean 88.9 ± 6.3) months. In 94 survivors, 6 (6.4%) late deaths were encountered. At last follow-up, 81 (86.2%) survivors were in NYHA class I. Actuarial survival was 84.7% ± 3.7% at 5, 10, and 15 years. Conclusion: Carefully selected adolescents and young adults can safely undergo the primary FO. However, persistent pleural effusions, arrhythmias, thromboembolic events, and the need for reoperation mandate regular follow-up in such patients. Preoperative NYHA functional class III, mean PA pressure ≧ 15 mm Hg, hematocrit ≥ 60%, ventricular dysfunction, and AVVR were associated with early mortality, suggesting that primary FO should be avoided in such patients.