Biomedical subjects

Rajesh Sharma

Publications and source records attributed to Rajesh Sharma.

24 records · Page 2Linked to original sources

PubMedDate not supplied

Oxidative stress and endothelial dysfunction in heart failure.

The clinical syndrome of congestive heart failure (CHF) is characterized by abnormalities of left ventricular function and neurohormonal regulation, which are accompanied by effort intolerance, fluid retention, and decreased longevity. While an increased sympathetic tone and an activated renin-angiotensin system may contribute to the reduced vasodilatory capacity in patients with CHF, the important role of the endothelium in coordinating tissue perfusion has now been recognized. CHF is associated with endothelial dysfunction, as demonstrated by impaired endothelium-mediated vasodilation. Endothelial dysfunction in patients with CHF is a critical component in the systemic vasoconstriction and reduced peripheral perfusion that characterizes these patients. Endothelial regulation of vascular tone is mediated mainly by nitric oxide. Increased oxidative stress in patients with CHF is likely caused by decreased bioavailability of nitric oxide due to reduced expression of endothelial nitric oxide synthase and increased generation of reactive oxygen species. These react with nitric oxide in the setting of decreased antioxidant defenses that would normally clear these radicals, culminating in attenuated endothelium-dependent vasodilation in patients with CHF. Therapies that improve endothelial function have been shown to improve exercise tolerance and outcomes in patients with CHF. Endothelial dysfunction is thus an important target for future therapy in patients with CHF.

Endothelium, Vascular↗

PubMedDate not supplied

Ventricular septal defect with congenital mitral valve disease: long-term results of corrective surgery.

BACKGROUND: A retrospective analysis of the mortality, morbidity and long-term follow-up of patients undergoing corrective surgery for ventricular septal defect and congenital mitral valve disease is presented. METHODS AND RESULTS: Between January 1991 and December 2000, 69 consecutive patients aged 2 months to 45 years (median 18 months) underwent repair of ventricular septal defect and associated mitral valve disease. In 52 patients (75%), the ventricular septal defects were located in the perimembranous and subarterial area. Forty-six patients had congenital mitral incompetence and 23 had congenital mitral stenosis. The ventricular septal defect was repaired through the right atrium in all. Sixty-five patients underwent reconstruction of the mitral valve and 4 underwent primary mitral valve replacement. Another 4 patients underwent mitral valve replacement after a failed repair. Associated procedures included: patent ductus arteriosus ligation (n=12), aortic valve replacement (n=6), coarctation repair (n=13), interrupted aortic arch repair (n=1), atrial septal defect closure (n=17) and Takeuchi repair (n=1). There were 6 early deaths (8.6%). Three deaths were due to pulmonary arterial hypertensive crisis and one due to residual mitral stenosis. One death was due to intractable congestive heart failure. Another patient died due to persistent low cardiac output. Follow-up ranged from 6 months to 120 months (mean 64.4+/-33.6 months). Reoperation was required in 22 patients, mainly for recurrent/residual mitral valve dysfunction or hemodynamically significant left ventricular outflow tract obstruction. There were 4 late deaths, 2 due to residual mitral stenosis and the other 2 as a result of a thrombosed prosthetic valve. At 10 years, the actuarial survival rate was 850+/-5.0%, and freedom from reoperation was 45%+/-10.0%. CONCLUSIONS: Reconstruction of the mitral valve along with closure of VSD is possible in most cases. However, careful follow-up is recommended to detect changes in the mitral valve status over a course of time.

Adolescent↗

PubMedDate not supplied

Medium-term outcome of anatomically repaired congenitally corrected transposition: the double switch operation.

BACKGROUND: The double switch operation is emerging as the procedure of choice for congenitally corrected transposition of the great arteries. However, rhythm disturbances in the postoperative period are rarely discussed. METHODS AND RESULTS: Eighteen survivors who underwent corrective surgery for congenitally corrected transposition of the great arteries were followed up. Patients in group I (n=8), who also had a ventricular septal defect and pulmonary stenosis, had undergone the Senning plus Rastelli operation. Patients in group II (n=10), who did not have pulmonary stenosis, had undergone the Senning and arterial switch operation. The patients were followed up by periodical clinical examination, echocardiography and 24-hour Holter monitoring. In group I, follow-up ranged from 24 to 66 months (mean 44 months). There was no late death and all the patients are symptom free. There was no significant atrioventricular valve regurgitation and left ventricular function was normal. There were no rhythm disturbances. In group II, follow-up ranged from 2 to 72 months (mean 48 months). There were 2 late deaths due to atrial tachyarrhythmia and residual pulmonary hypertension 36 and 8 months after the procedure, respectively. One patient had significant mitral regurgitation and required mitral valve replacement. Three patients had recurrent atrial/junctional tachyarrhythmia: one of them was lost to follow-up after 1 year while another died of resistant atrial tachyarrhythmia. The third patient underwent mitral valve replacement for severe mitral regurgitation and developed complete heart block necessitating a permanent pacemaker implantation. CONCLUSIONS: Though good long-term results are obtained following the double switch operation, the problem of atrial arrhythmias still needs to be addressed suitably.

Adolescent↗

PubMedDate not supplied

Total anomalous pulmonary venous connection: helical computed tomography as an alternative to angiography.

BACKGROUND: Echocardiographic evaluation of the pulmonary veins is inadequate at times. Cardiac catheterization, especially in sick neonates, may be a high-risk procedure. Helical computed tomography with three-dimensional reconstruction is noninvasive but remains an underutilized modality. METHODS AND RESULTS: Between January 2002 and February 2003, 7 computed tomography scans of children 3 weeks to 5 years of age were performed to evaluate the drainage of the pulmonary veins in suspected total anomalous venous drainage. Helical computed tomography (GE High speed Advantage) was performed using 2 mm sections, and rapid bolus hand injections of 2 ml/kg body-weight of nonionic intravenous contrast. Sagittal and coronal reformats, and three-dimensional reconstructions were performed, and reviewed by the radiologist. The findings were discussed with the pediatric cardiologist and surgeon involved in the case. The diagnoses included complex congenital heart disease (n = 5), isolated infradiaphragmatic total anomalous pulmonary venous connections (n = 1), and transposition of the great arteries with total anomalous pulmonary venous connections (n = 1). Cardiac computed tomography accurately demonstrated infradiaphragmatic total anomalous pulmonary venous connections in 4, and supracardiac drainage in 3 patients, in addition to the other cardiac findings. The findings on computed tomography scan correlated with surgical (n = 5) and/or angiographic findings (n = 2) in 7 patients. CONCLUSIONS: In sick, high-risk patients, cardiac computed tomography can be considered as an alternative to cardiac catheterization for the evaluation of pulmonary venous drainage.

Angiography↗

PubMedDate not supplied

Surgical outcome of staged univentricular-type repairs for patients with univentricular physiology and pulmonary hypertension.

BACKGROUND: There is no consensus about the most appropriate limits of pulmonary artery pressure and vascular resistance in case of patients undergoing univentricular or one and one-half ventricular repair. This study was conducted to analyze the mortality and morbidity of a heterogenous group of patients with a functionally univentricular heart and pulmonary artery hypertension, undergoing pulmonary artery banding followed by univentricular-type repairs. METHODS AND RESULTS: Out of 254 patients undergoing pulmonary artery banding for a functionally univentricular heart with increased pulmonary blood flow, 148 patients underwent definitive second stage surgery. Post-band hemodynamic evaluation revealed persistently high pulmonary artery pressure (> 18 mmHg), and pulmonary vascular resistance (>2.0 Woods units/m2) in 78.3% patients. Sixteen patients with moderate right ventricular hypoplasia were given a one and one-half ventricle repair (Group I), 82 patients a bidirectional Glenn connection (Group II), and 50 patients a fenestrated total cavopulmonary connection (Group III). The overall mortality following second stage surgery for the high pulmonary artery pressure group (n=116) was 30.17%, while none of the low pulmonary artery pressure group died (p=0.0009). Pulmonary hypertensive crises and/or systemic desaturation were the main causes of death at second stage repair. All mortality occurred in patients with mean pulmonary artery pressure > 18 mmHg and pulmonary vascular resistance > 3.5 Woods units/m2. Survivors from this group had persistent morbidity in the form of superior vena caval syndrome and suboptimal oxygen saturation (70-75%). CONCLUSIONS: It is advisable not to proceed with definitive second stage repair if post-pulmonary artery banding mean pulmonary artery pressure is over 25 mmHg and pulmonary vascular resistance exceeds 4.0 Woods units/m2. These patients may possibly be deemed to have undergone definitive palliation during their pulmonary artery banding.

Cardiac Surgical Procedures↗

PubMedDate not supplied

Transposition of great arteries with aortopulmonary window: an unusual cause of prepared left ventricle at 11 months.

In patients with transposition of great arteries, presence of aortopulmonary window is very uncommon and associated with high morbidity and mortality. This report describes the case of an 11-month-old female patient in which aortopulmonary window was restrictive, and protected the patient from developing pulmonary vascular disease. The patient underwent successful arterial switch and repair of aortopulmonary window.

Aortopulmonary Septal Defect↗