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Narayanswami Sreeram - One of the best experts on this subject based on the ideXlab platform.

  • Tetralogy of fallot
    Current Treatment Options in Cardiovascular Medicine, 2001
    Co-Authors: Samantha C. Gouw, Thuy-nga Le, Narayanswami Sreeram
    Abstract:

    The optimal surgical approach and timing for patients with tetralogy of Fallot remain controversial. There are two options in current practice: a two-stage repair (an initial palliative Aortopulmonary Shunt at an early age followed by complete repair at an older age) or primary complete repair. There has been a trend towards primary repair at a young age, which can be attributed to advances in anesthetic and cardiac surgical techniques. Primary repair has several advantages. The correction can be done in one operation and Shunt complications are avoided. Progressive right ventricular fibrosis, ventricular hypertrophy, and chronic hypoxia are avoided, which may reduce the incidence of late ventricular arrhythmias. However, surgical correction at a young age is associated with an increased incidence of transannular patching and consequent pulmonary regurgitation. Progressive pulmonary regurgitation is associated with late ventricular arrhythmias and sudden death. These consequences may be prevented by timely pulmonary valve replacement. Palliative procedures include an Aortopulmonary Shunt, balloon dilation of the right ventricular tract, and stent placement. Of these measures, the Aortopulmonary Shunt is preferred, as it results in a more predictable outcome. Complications associated with Shunt placement include Shunt occlusion, pulmonary artery distortion, and occasionally, volume overloading of the left ventricle and pulmonary circulation. Institutional and surgeon preferences exist for either surgical strategy, and ultimately are justifiable when they produce the best outcomes for the individual patient. The optimal surgical strategy has to be determined by large prospective randomized studies that compare the functional status of the pulmonary valve and the need for reoperation at long-term follow-up.

  • Competitive pulmonary flow in infancy: the effect of respiration
    International journal of cardiology, 1999
    Co-Authors: H.t. Henneveld, Narayanswami Sreeram, J F Hitchcock
    Abstract:

    Superior caval flow during positive pressure mechanical ventilation and spontaneous breathing was investigated by Doppler echocardiography in a neonate with a coexisting superior cavopulmonary Shunt and an Aortopulmonary Shunt. During positive pressure ventilation, retrograde systolic flow in the superior vena cava was recorded, with low velocity anterograde flow. This pattern was reversed during spontaneous respiration. Low intrathoracic pressure plays an important role in maintaining anterograde pulmonary blood flow in patients with this physiology.

  • An unusual palliative Shunt for cyanotic congenital heart disease
    Heart (British Cardiac Society), 1997
    Co-Authors: Narayanswami Sreeram, H.t. Henneveld, J F Hitchcock
    Abstract:

    An 11 year old boy was referred for surgical correction of tetralogy of Fallot, having undergone a palliative Aortopulmonary Shunt in eastern Europe seven years previously. Clinical examination …

  • Univentricular heart with systemic outflow obstruction: Palliation by primary Damus procedure
    The Annals of thoracic surgery, 1995
    Co-Authors: William J. Brawn, Babulal Sethia, Ranjit Jagtap, Oliver Stumper, John G.c. Wright, Joseph V. De Giovanni, Eric D. Silove, Mark Jackson, Narayanswami Sreeram
    Abstract:

    In 24 consecutive infants (19 male and 5 female) with complex forms of single-ventricle physiology and systemic outflow obstruction, a modified Damus operation without the use of exogenous material was undertaken in conjunction with creation of an Aortopulmonary Shunt 3.5 mm in diameter. The median age at operation was 6 days (range, 1 to 170 days) and the median weight, 3.4 kg (range, 2.6 to 4.6 kg). There were nine early deaths. All 15 survivors (median follow-up, 6.5 months) were clinically well without major systemic ventricular dysfunction or atrioventricular or arterial valve regurgitation. Ten of them have undergone a superior vena cava—pulmonary Shunt (one death), and 1 has required patch angioplasty of the aortic arch and innominate artery with revision of the Aortopulmonary Shunt. The 4 other survivors are awaiting a cavopulmonary Shunt. Univariate analysis yielded the chronologic rank for an individual procedure (higher risk of death early in the series), presence of aortic arch atresia, and presence or absence of transposition of the great arteries as predictors of death. This aggressive surgical approach provides excellent early palliation, and because the operation prevents abnormal ventricular hypertrophy from pressure or volume overload, systemic ventricular function is optimally conserved for a future Fontan-type procedure.

  • Results of balloon pulmonary valvuloplasty as a palliative procedure in tetralogy of Fallot.
    Journal of the American College of Cardiology, 1991
    Co-Authors: Narayanswami Sreeram, Moin Saleem, Mark J. Jackson, Ian Peart, Roxane Mckay, Robert M. Arnold, Kevin P. Walsh
    Abstract:

    Balloon pulmonary valvuloplasty was attempted in 67 patients with tetralogy of Fallot at a median age of 5 months (range 0.03 to 52 months) for relief of cyanosis. In three patients, the valve could not be crossed and an Aortopulmonary Shunt was performed. In 35 patients, follow-up angiography was performed 3 to 30 months (average 12) after valvuloplasty. In 24 of these 35 patients (group A), the stenosis had been adequately palliated by valvuloplasty; the other 11 patients (group B) had required an Aortopulmonary Shunt 1 month (range 0 to 3 months) after valvuloplasty. The two groups were similar (p > 0.1) with respect to age at valvuloplasty, pulmonary anulus diameter, ratio of pulmonary artery to descending aorta diameter before valvuloplasty and interval to follow-up angiography. In contrast to patients in group B, patients in group A had a significant immediate improvement in systemic arterial oxygen saturation (p 0.1) in the two groups. Among 42 patients who have had surgical correction, a transannular patch for right ventricular outflow tract reconstruction was used in 27 (64%); there was no difference between groups A and B with respect to its use. Eight patients died (three after repair) and death could not be directly attributed to valvuloplasty in any. Balloon valvuloplasty promotes growth of the pulmonary valve anulus and pulmonary arteries and is a useful alternative to an Aortopulmonary Shunt in patients with small pulmonary arteries or associated complex intracardiac defects.

Meryl S. Cohen - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Patterns of Pulmonary Venous Blood Flow in the Functional Single Ventricle Heart After Operative Aortopulmonary Shunt Versus Superior Cavopulmonary Shunt
    The American journal of cardiology, 1997
    Co-Authors: Jack Rychik, Mark A. Fogel, Mary T. Donofrio, Elizabeth Goldmuntz, Meryl S. Cohen, Thomas L. Spray, Marshall L. Jacobs
    Abstract:

    In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and Aortopulmonary Shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p

  • comparison of patterns of pulmonary venous blood flow in the functional single ventricle heart after operative Aortopulmonary Shunt versus superior cavopulmonary Shunt
    American Journal of Cardiology, 1997
    Co-Authors: Jack Rychik, Mark A. Fogel, Mary T. Donofrio, Elizabeth Goldmuntz, Meryl S. Cohen
    Abstract:

    In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and Aortopulmonary Shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p <0.001). In both groups, pulmonary venous flow was predominantly systolic; however, the proportion of flow during ventricular systole was significantly greater in group II than in group I (S(VTI)/D(VTI) group II: 2.4 +/- 1.5; group I 1.4 +/- 0.5, p = 0.001; percent systolic fraction of pulmonary venous flow group II = 67%, group I = 56%, p <0.001). Analysis of superior vena caval flow in group II revealed a single predominant wave with onset at early systole and peak in late systole at a mean of 150 ms after the pulmonary venous S-wave peak. Our data suggest that ventricular systole (i.e., atrial relaxation, atrioventricular valve descent) asserts great influence on transpulmonary blood flow in the functional single ventricle.

Jack Rychik - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Patterns of Pulmonary Venous Blood Flow in the Functional Single Ventricle Heart After Operative Aortopulmonary Shunt Versus Superior Cavopulmonary Shunt
    The American journal of cardiology, 1997
    Co-Authors: Jack Rychik, Mark A. Fogel, Mary T. Donofrio, Elizabeth Goldmuntz, Meryl S. Cohen, Thomas L. Spray, Marshall L. Jacobs
    Abstract:

    In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and Aortopulmonary Shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p

  • comparison of patterns of pulmonary venous blood flow in the functional single ventricle heart after operative Aortopulmonary Shunt versus superior cavopulmonary Shunt
    American Journal of Cardiology, 1997
    Co-Authors: Jack Rychik, Mark A. Fogel, Mary T. Donofrio, Elizabeth Goldmuntz, Meryl S. Cohen
    Abstract:

    In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and Aortopulmonary Shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p <0.001). In both groups, pulmonary venous flow was predominantly systolic; however, the proportion of flow during ventricular systole was significantly greater in group II than in group I (S(VTI)/D(VTI) group II: 2.4 +/- 1.5; group I 1.4 +/- 0.5, p = 0.001; percent systolic fraction of pulmonary venous flow group II = 67%, group I = 56%, p <0.001). Analysis of superior vena caval flow in group II revealed a single predominant wave with onset at early systole and peak in late systole at a mean of 150 ms after the pulmonary venous S-wave peak. Our data suggest that ventricular systole (i.e., atrial relaxation, atrioventricular valve descent) asserts great influence on transpulmonary blood flow in the functional single ventricle.

Jaap R. G. Kuipers - One of the best experts on this subject based on the ideXlab platform.

  • METABOLIC RESPONSE TO MODERATE EXERCISE IN LAMBS WITH AN Aortopulmonary Shunt
    Pediatric Research, 1994
    Co-Authors: Gertie C. M. Beaufort-krol, Janny Takens, Gioia B. Smid, Willem Zijlstra, Jaap R. G. Kuipers
    Abstract:

    The normal metabolic response to moderate exercise consists of a slight increase in glucose (glue) and a considerable increase in free fatty acids (FFA) in blood. In earlier studies we have demonstrated that at rest, after an overnight fast, lambs with an Aortopulmonary Shunt (SH) had lower concentrations of glue and FFA than control (C) lambs. We wondered, whether SH lambs with low glue and FFA were able to increase their arterial concentrations during exercise just like C lambs. Therefore, we studied 6 7-week-old SH lambs and 6 C lambs of the same age after an overnight fast at rest and during moderate exercise (tredmill; 50 % of Vo2-max; 30 rain). At rest as well as during exercise, 3 blood samples were taken at intervals of 10 min. At rest, mean arterial concentrations (mmol/l) of glue (SH: 3.37 ± 0.21 vs. C; 4.48 ± 0.53, mean ± SD, p < 0.05) and FFA (SH: 0.57 ± 0.17 vs. C: 0.80 ± 0.20, p < 0.05) were lower in SH than in C lambs. During exercise, glue (SH: 3.59 ± 0.19 vs. C: 5.15 ± 0.80, p < 0.05) and FFA (SH: 0.79 ± 0.32 vs. C: 1.23 ± 0.43, p < 0.05) increased significantly in SH and C lambs (p < 0.05). However, the relative increment of glue during exercise was lower in SH than in C lambs (7 ± 5 % vs. 15 ± 7 %, p < 0.05). The relative increment of FFA was not different (SH: 38 ± 37 % vs. C: 56 ± 47 %, p = 0.48). We conclude that, despite lower gluc and FFA at rest, SH lambs demonstrate a metabolic response of increment of gluc and FFA during moderate exercise like C lambs, However, the relative increment for gluc was lower in SH lambs. We speculate that this is due to an earlier glycogen depleted state in SH lambs.

  • distribution of systemic blood flow in lambs with an Aortopulmonary Shunt during strenuous exercise
    Journal of Applied Physiology, 1992
    Co-Authors: Jwc Gratama, Willem G. Zijlstra, M. Dalinghaus, J. H. Koers, J. J. Meuzelaar, S Gratama, Jaap R. G. Kuipers
    Abstract:

    We studied regional blood flows with radioactive-labeled microspheres in 12 7-wk-old lambs with an Aortopulmonary left-to-right Shunt [59 +/- 3% (SE) of left ventricular (LV) output] and in 11 control lambs, at rest and during exercise at 80% of predetermined peak O2 consumption. At rest, systemic blood flow was similar in the two groups. Blood flow to the heart and diaphragm was substantially higher in the Shunt than in the control lambs. Blood flow to the other organs was not significantly different between the two groups. During exercise, systemic blood flow increased substantially but less in Shunt (81%) than in control lambs (134%). Blood flow to the heart and diaphragm increased, that to the heart still being higher in Shunt than in control lambs. Blood flow to the brain did not change, whereas that to the kidneys and splanchnic organs decreased to the same extent (25%) in Shunt and control lambs. Intrahepatic and intrarenal blood flow redistribution in the Shunt lambs persisted during exercise. In conclusion, myocardial blood flow is not increased at the expense of one particular organ, nor is it associated with an essential change in exercise-induced redistribution in Shunt lambs.

Mark A. Fogel - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Patterns of Pulmonary Venous Blood Flow in the Functional Single Ventricle Heart After Operative Aortopulmonary Shunt Versus Superior Cavopulmonary Shunt
    The American journal of cardiology, 1997
    Co-Authors: Jack Rychik, Mark A. Fogel, Mary T. Donofrio, Elizabeth Goldmuntz, Meryl S. Cohen, Thomas L. Spray, Marshall L. Jacobs
    Abstract:

    In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and Aortopulmonary Shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p

  • comparison of patterns of pulmonary venous blood flow in the functional single ventricle heart after operative Aortopulmonary Shunt versus superior cavopulmonary Shunt
    American Journal of Cardiology, 1997
    Co-Authors: Jack Rychik, Mark A. Fogel, Mary T. Donofrio, Elizabeth Goldmuntz, Meryl S. Cohen
    Abstract:

    In this study we investigated the patterns of pulmonary venous flow in children with functional single ventricles to obtain a better understanding of the determinants of transpulmonary blood flow. Sixty-eight patients with functional single ventricles and Aortopulmonary Shunt (n = 34, group I), or superior cavopulmonary connection (n = 34, group II) underwent transesophageal Doppler echocardiographic assessment of flow in the left upper pulmonary vein before undergoing the next stage of surgery. Twelve patients from group II also underwent simultaneous evaluation of superior vena caval flow. Biphasic forward pulmonary venous flow was noted in 62 patients in sinus rhythm (S wave in systole, D wave in diastole); in 6 patients with junctional rhythm, significant early systolic reversal of flow was present. Both the S- and D-wave velocity-time integrals (VTI) were greater in group I than in group II (S(VTI) 9.9 +/- 4.2 vs 8.0 +/- 2.6, p = 0.02; D(VTI) 8.0 +/- 3.5 vs 4.2 +/- 2.6, p <0.001). In both groups, pulmonary venous flow was predominantly systolic; however, the proportion of flow during ventricular systole was significantly greater in group II than in group I (S(VTI)/D(VTI) group II: 2.4 +/- 1.5; group I 1.4 +/- 0.5, p = 0.001; percent systolic fraction of pulmonary venous flow group II = 67%, group I = 56%, p <0.001). Analysis of superior vena caval flow in group II revealed a single predominant wave with onset at early systole and peak in late systole at a mean of 150 ms after the pulmonary venous S-wave peak. Our data suggest that ventricular systole (i.e., atrial relaxation, atrioventricular valve descent) asserts great influence on transpulmonary blood flow in the functional single ventricle.