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Biomedical subjects

Navin C Nanda

Publications and source records attributed to Navin C Nanda.

At least 73 records · Page 4Linked to original sources
PubMed2003

Relative perioperative bradycardia does not lead to adverse outcomes after cardiac transplantation.

Since the effects of bradycardia after cardiac transplantation are not known, we tested the hypothesis that perioperative bradycardia would lead to an increase in adverse outcomes after cardiac transplantation. We conducted a retrospective case control study with inclusion criterion of a heart rate (HR) less than 80 bpm during the 1st week after transplantation. Control patients were matched for gender, age and time since transplantation. We identified 34 patients as having perioperative bradycardia out of the 174 who underwent cardiac transplantation between 1994 and 1997. The results demonstrated no significant differences in donor ischemic times (180 vs. 183, p = 0.88), operative surgeon (p = 0.62) or pretransplant cardiac disease (p = 0.81) between groups. Bradycardic patients were more likely to be on pretransplant amiodarone (RR = 20.4, p < 0.001). Perioperative bradycardia did not lead to increases in cellular rejection (p = 0.72) or vasculopathy (p = 0.79). The patients prescribed pretransplant amiodarone (n = 14) had a trend toward delayed time to first rejection episode (31.0 vs. 15.5 days, median, p = 0.07). In conclusion, perioperative bradycardia does not increase adverse outcomes after cardiac transplantation and is associated with pretransplant use of amiodarone. Amiodarone may modify the recipients' immune response by delaying the occurrence of rejection.

Amiodarone↗
PubMed2003

Three-dimensional transesophageal echocardiographic demonstration of anatomical defects in AV septal defect patients presenting for reoperation.

We present two- and three-dimensional transesophageal echocardiographic findings of two adult patients who presented for reoperation after previous repair of a partial atrioventricular (AV) septal defect. Both patients had a cleft in the left AV valve with severe regurgitation. One patient had an additional 10 x 5 mm defect connecting the left ventricle to the right atrium through the AV junction. Three-dimensional echocardiography was superior to two-dimensional echocardiography in comprehensively delineating the anatomical defects in the left AV valve and the AV junction.

Adult↗
PubMed2003

Usefulness of transesophageal three-dimensional echocardiography in the identification of individual segment/scallop prolapse of the mitral valve.

We evaluated the potential usefulness of three-dimensional (3D) transesophageal echocardiography (TEE) in assessing individual scallop/segment prolapse in 36 adult patients with mitral valve prolapse (MVP) undergoing surgical correction. Intraoperative 3D TEE correctly identified the location of scallop/segment prolapse in 34 of 36 patients (94%). However, in 6 of these patients 3D TEE images revealed more scallops or segments with prolapse than the surgeon noted intraoperatively. Prolapse of these areas was less prominent and this could possibly explain the lack of correlation with the surgical findings in these patients. In another 2 patients areas of prolapse seen by the surgeon were missed by 3D TEE because some of those scallops/segments could not be well imaged due to image "drop out" and artifacts. Thus, perfect correlation between 3D TEE and surgery was noted in 28 of 36 (78%) patients. Noncoaptation of the MV was also identified in 2 patients. The prolapsed area of posterior (n = 28 observations) and anterior (n = 9 observations) MV leaflets ranged from 1 cm2 to 9 cm2 (mean 3.50 cm2+/- 2.14) and 1.20 cm2 to 5.99 cm2 (mean 3.21 cm2+/- 1.33), respectively. Interobserver and intraobserver agreement for location and area of MVP was excellent (r = 0.97 and r = 0.99, respectively; all P values are <0.0001). In conclusion, 3D TEE is useful in identifying the location of MVP. It may also be potentially useful in assessing the extent of individual scallop/segment prolapse and identifying sites of MV noncoaptation. This information could aid the surgeon in deciding the extent of MV resection.

Adult↗
PubMed2003

Imagent improves endocardial border delineation, inter-reader agreement, and the accuracy of segmental wall motion assessment.

BACKGROUND: This study was conducted to assess the ability of a new echocardiographic contrast agent, Imagent (perflexane lipid microspheres; Alliance Pharmaceutical Corp., San Diego, CA), to improve endocardial border delineation (EBD) and assessment of segmental wall motion (SWM). This was achieved by analysis of inter-reader agreement by echocardiography and comparison with an independent imaging technique, magnetic resonance imaging (MRI). METHODS: Two separate, independent, prospective, randomized, controlled, multicenter trials were conducted at 26 centers and included a total of 409 efficacy-evaluable patients. In Study A 206 patients were randomized to receive either Imagent or saline and in Study B, 203 patients received Imagent with a subset imaged by both echocardiography and MRI. All patients were required to have suboptimal baseline images using fundamental imaging. Images were optimized at baseline prior to contrast and the settings maintained post-contrast. Imagent, a suspension of perfluorohexane-filled spheres with flexible lipid shells, was administered as an IV bolus at 0.125 mg/kg body weight. Gated MRI studies were performed within 48 hours of dosing in a subset of 26 subjects. Six expert independent blinded readers reviewed unpaired noncontrast and contrast exams and scored EBD and SWM. Analysis of inter-reader agreement was performed by comparing the SWM score (1 to 5) recorded by each reader pair. In addition, unanimity between readers for SWM was evaluated. For comparison to MRI, the results from echo readers 4, 5, and 6 were each compared with a single independent MRI reader. RESULTS: The patients enrolled in these clinical trials displayed markedly suboptimal images with 49% and 71% (Study A and Study B) of the segments determined by the readers to be suboptimal prior to contrast administration. All readers recorded statistically significant (P < 0.0001) improvement in total EBD scores following the administration of Imagent. Comparison of noncontrast SWM scores for each pair of echo readers resulted in agreement in an average of 39%, of segments in Study A, and 31% of the segments in Study B. Use of Imagent improved agreement in SWM scores to 65% in Study A, and 48% of segments in Study B (P < 0.0001) for all reader pairs in both studies. Reader unanimity in SWM scores increased from 13% to 41% of the segments with the administration of Imagent. Blinded review of the noncontrast echo examinations resulted in agreement with MRI derived SWM scores in 15% of the segments. The administration of Imagent improved this agreement to 47%, of the segments (P < pr = 0.0005 for each blinded reader). CONCLUSIONS: Use of Imagent during echocardiographic imaging improves EBD, providing a significant improvement in inter-reader agreement in SWM evaluation with echo and greater than a threefold improvement in SWM scoring accuracy with MRI.

Adult↗
PubMed2003

Platypnea-orthodeoxia in a patient with ostium primum atrial septal defect with normal right heart pressures.

We describe an adult patient with an ostium primum atrial septal defect (ASD) and a patent foramen ovale (PFO) with normal right heart pressures who presented with platypnea and orthodeoxia. A dilated aortic root encroaching into the region of the ASD and PFO, along with a tricuspid regurgitant jet moving into the left atrium through the ASD found on the transesophageal echocardiogram may have been responsible for orthodeoxia. Surgical closure of these defects resulted in the disappearance of both platypnea and orthodeoxia.

Echocardiography, Transesophageal↗
PubMed2003

Transesophageal three-dimensional echocardiographic demonstration of Ebstein's anomaly.

We report three-dimensional transesophageal echocardiographic findings in an adult patient with Ebstein's anomaly. Using the anyplane technique and multiple views, especially the short-axis view of tricuspid valve, three-dimensional transesophageal echocardiography clearly demonstrated the intermittent tethering of all three leaflets of tricuspid valve to the right ventricular walls giving a "bubble-like" appearance. On the other hand, two-dimensional transesophageal echocardiography demonstrated well the tethering of the septal tricuspid leaflet, but tethering of the other two leaflets was not well seen. To our knowledge, these findings have not been demonstrated by three-dimensional transesophageal echocardiography before.

Adult↗
PubMed2003

Contrast transesophageal echocardiographic detection of a pulmonary arteriovenous malformation draining into left lower pulmonary vein.

We report the identification of a pulmonary arteriovenous malformation draining into the left lower pulmonary vein by contrast two-dimensional transesophageal echocardiography in an adult with no evidence of hereditary hemorrhagic telangiectasia. To our knowledge, this has not been reported previously. This study also emphasizes the importance of transesophageal echocardiographic examination of the left lower pulmonary vein in the detection of a pulmonary arteriovenous malformation.

Arteriovenous Malformations↗
PubMed2003

Transesophageal echocardiographic identification of bilateral vertebral artery ostial stenosis.

We describe the usefulness of transesophageal echocardiography in correctly diagnosing severe ostial stenosis of both the left and right vertebral arteries in an adult patient. Although transesophageal echocardiography has been previously used to identify left vertebral artery stenosis, to our knowledge this study represents the first demonstration of its usefulness in detecting bilateral vertebral artery ostial stenosis.

Echocardiography↗
PubMed2003

Normal lymph nodes mimicking a mediastinal mass during transesophageal echocardiography.

We report a transesophageal echocardiographic (TEE) study in an adult patient with ischemic stroke, in whom a nodular mass lesion consistent with tumor or mediastinal lymphadenopathy appeared to be interposed between the esophageal probe and the proximal descending aorta/aortic arch. Computed tomography (CT) scan of the chest revealed no pathologic lesions, only the presence of normal mediastinal lymph nodes and a rightward displaced esophagus. This unusual, but normal rightward position of the esophagus appears to have facilitated the visualization of these normal mediastinal lymph nodes on TEE. CT scan of the chest helped clarify the benign nature of these lymph nodes, which mimicked a mediastinal mass on TEE.

Diagnosis, Differential↗
PubMed2003

Live three-dimensional echocardiography: imaging principles and clinical application.

Live three-dimensional echocardiography (L3DE) is an important breakthrough in the field of medical ultrasound. It will provide a great potential tool for clinical diagnosis and treatment. In this article, the authors first review the bottlenecks in 3D cardiac imaging and the technical principles of L3DE that have been used to overcome some of these problems. We then discuss the scanning methods, clinical usefulness, and the future of L3DE, drawing on our experiences in examining 124 human patients and in conducting animal verification studies with a live 3D ultrasound system.

Echocardiography, Three-Dimensional↗
PubMed2003

Live three-dimensional echocardiography of the human fetus.

The purpose of this study was to investigate the feasibility of using a new three-dimensional ultrasound system to perform fetal echocardiographic examination in real time. The device consisted of a Philips Sonos 7500 (Andover, MA) ultrasound system and a 4 MHz, 4X matrix transducer. The study was approved by the Institutional Review Board and was performed with the informed consent of the mother. The study population consisted of 12 singleton fetuses with gestational ages of 16-37 weeks. Of these, ten fetuses had normal cardiac anatomy, one had complete atrioventricular septal defect, and the other a thickened tricuspid valve. The system allowed comprehensive visualization of fetal cardiac anatomy and color Doppler flow unattainable by two-dimensional approaches. This preliminary investigation suggests that live three-dimensional fetal echocardiography could be a significant tool for prenatal diagnosis and assessment of congenital heart disease in the human fetus.

Cohort Studies↗