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Biomedical subjects

A Sampath Kumar

Publications and source records attributed to A Sampath Kumar.

At least 19 recordsLinked to original sources
PubMed2006

Pericardiectomy for constrictive pericarditis: a clinical, echocardiographic, and hemodynamic evaluation of two surgical techniques.

BACKGROUND: This study was designed to compare the outcomes after total versus partial pericardiectomy clinically, echocardiographically, and hemodynamically. METHODS: Three hundred ninety-five patients undergoing pericardiectomy for constrictive pericarditis between January 1985 and December 2004 were studied. Age was 10 months to 71 years (mean, 25.1 +/- 13.4 years). Three hundred thirty-eight patients (85.6%) underwent total pericardiectomy (group I), and 57 patients (14.4%) underwent partial pericardiectomy (group II). RESULTS: Operative and late mortality rates were 7.6% and 4.9%, respectively. Preoperative high right atrial pressure, hyperbilirubinemia, renal dysfunction, atrial fibrillation, pericardial calcification, thoracotomy approach, and partial pericardiectomy were significant risk factors for death. The risk of death was 4.5 times higher (95% confidence interval: 2.05 to 9.75) in patients undergoing partial pericardiectomy. At a mean follow-up of 17.9 +/- 0.3 years (95% confidence interval: 17.3 to 18.6), actuarial survival was 83.8% +/- 0.04% in group I and 73.9% +/- 0.06% in group II (p = 0.004). At their last follow-up, 96.3% survivors of group I and 79.1% survivors of group II were in New York Heart Association class I/II (p < 0.001). CONCLUSIONS: Total pericardiectomy is associated with lower perioperative and late mortality, and confers significant long-term advantage by providing superior hemodynamics that appear to be independent of the etiology of constrictive pericarditis.

Adolescent↗
PubMed2006

Noninvasive assessment of repaired tetralogy of Fallot by magnetic resonance imaging and dynamic radionuclide studies.

BACKGROUND: This study was designed to validate the diagnostic accuracy of magnetic resonance imaging (MRI) in evaluating biventricular ejection fraction and to quantify pulmonary regurgitant fraction (PRF) in patients after repair of tetralogy of Fallot. METHODS: Two hundred and eighty survivors of repaired tetralogy of Fallot aged 42 months to 40 years (mean, 142.2 +/- 85.3 months) underwent cardiac MRI, first-pass and gated radionuclide ventriculography (RNV) for the assessment of biventricular function, and PRF after 89.26 +/- 42.40 months. The receiver operating characteristic curve analysis was done to quantify the diagnostic accuracy of MRI. RESULTS: There was statistically significant agreement between MRI and RNV in evaluating right and left ventricular function. An MRI-derived right ventricular ejection fraction 47.2% or greater than normal was associated with a sensitivity of 92.3% and a specificity of 92.3%. An MRI-derived left ventricular ejection fraction 53.9% or greater than normal was associated with a sensitivity of 93.2% and a specificity of 93.3%. Area analysis indicated that 97.34% (standard error [SE] = 0.0118) and 98.56% (SE = 0.0052) of the time values of right and left ventricular ejection fraction were higher for patients with normal right and left ventricular functions, respectively, compared with abnormal. There was a strong agreement between velocity-encoded and stroke volume-derived PRF [(r = 0.886, p < 0.001; d = 2.62 +/- 1.12, p < 0.0001; r' = 0.121, p = 0.051; b = 0.96 (SE = 0.012); p < 0.0001; ICC = 0.98, p < 0.0001). Higher PRF was associated with increased indexed right ventricular dimensions and inversely correlated with biventricular ejection fractions. CONCLUSIONS: The MRI-derived ejection fraction values predictably separate patients with normal ventricular function from abnormal. Velocity-encoded MRI can accurately quantitate PRF in tetralogy of Fallot.

Adolescent↗
PubMed2006

Criterions for selection of patients for, and results of, a new technique for construction of the modified Blalock-Taussig shunt.

BACKGROUND: We describe alternative surgical techniques for construction of systemic-to-pulmonary arterial shunts, and propose criterions for their application in selected patients. PATIENTS AND METHODS: We constructed a variety of modified systemic-to-pulmonary arterial shunts, using polytetrafluoroethylene grafts, in 92 selected patients with cyanotic congenital heart disease and anomalies of the aortic arch and systemic veins. Their age ranged from 7 days to 3.6 years, with a mean of 7.08 months. We performed 88 operations through a thoracotomy. Of this cohort, 60 patients underwent a second-stage operation, with 15 receiving a superior cavopulmonary connection, 16 a total cavopulmonary connection, and 29 proceeding to biventricular repair after a mean interval of 15.6 months. We have 21 patients awaiting their second or final stage of palliation. RESULTS: There were five early (5.4%) and six late deaths (6.8%), two of which were related to construction of the shunts. At a mean follow-up of 45.29 months, the increase in diameter of pulmonary trunk and its right and left branches was uniform and significant (p value less than 0.001). Pulmonary arterial distortion requiring correction at the time of second-stage operation was observed in 5 patients (6.1%). Adequate overall palliation was achieved in 98% of the cohort at 8 months, 91% at 12 months, and 58% at 18 months. CONCLUSIONS: Patients with a right- or left-sided aortic arch and right-sided descending thoracic aorta, those with anomalies of systemic venous drainage masking the origin of great arterial branches, and those with disproportionately small subclavian arteries, constitute the ideal candidates for our suggested modification of the construction of a modified Blalock-Taussig shunt. The palliation provided by these shunts was satisfactory, with predictable growth of pulmonary arteries, insignificant distortion in the great majority, and easy take-down.

Anastomosis, Surgical↗
PubMed2006

Sewing needle in the heart.

An unusual case of a sewing needle in the heart is reported for its rarity. The relevant literature is briefly reviewed.

Cardiac Surgical Procedures↗
PubMed2006

Comparison of straight sternotomy and interlocking sternotomy in open heart surgery.

BACKGROUND AND OBJECTIVES: Stable sternal approximation is an important factor to avoid respiratory complications after open heart surgery. The present study is designed to compare interlocking sternotomy and straight sternotomy in terms of sternal stability, pain and respiratory function. METHODS: Sixty patients scheduled for open heart surgery underwent a standard midline sternotomy (n=30) or an interlocking sternotomy (n=30). The features assessed were pain on visual analogue scale during rest and during cough, peak expiratory flow rate and sternal instability. Evaluation was performed on the first, fourth post-operative days, on discharge and one month and three month follow up. RESULTS: Analysis of the peak expiratory flow rates, visual analogue ratings of pain intensity at rest and on coughing were carried out for each group only for those patients who completed the study. Postoperatively, in all patients there was significant reduction in peak expiratory flow rates. In the straight sternotomy group resting pain intensity was higher on discharge (2.6+/- 2 vs 1.6 +/- 2.3, P= 0.005). In the interlocking sternotomy group pain on coughing was significantly less than straight sternotomy group (median 0.5 vs 2.8, P=0.005) at 1 month follow up and at 3 months (median 0 vs 1.6, P=0.003). INTERPRETATION AND CONCLUSION: Interlocking sternotomy can be performed with good functional results and offers a less painful alternative to straight sternotomy.

Adolescent↗
PubMed2005

Mitral valve replacement with and without chordal preservation in a rheumatic population: serial echocardiographic assessment of left ventricular size and function.

BACKGROUND: The aim of this study is to investigate the feasibility of chordal-sparing mitral valve replacement procedures in a rheumatic population, and to determine the early and late effects of different chordal preservation procedures on the clinical outcome and left ventricular mechanics. METHODS: Various techniques of chordal preservation during mitral valve replacement for rheumatic heart disease in 451 patients between 1996 and 1999 are described. The mean age was 35.6 +/- 19.0 years (range, 15 to 55 years). Seventy patients had complete excision of the subvalvular apparatus (group I), 124 had preservation of the posterior chordopapillary apparatus (group II), and 257 had total chordal preservation (group III). Echocardiography was performed preoperatively, at discharge, at 1 year, and at 4 years. RESULTS: Chordal preservation groups (II and III) demonstrated significant improvement (p < 0.05) in left ventricular function immediately and late postoperatively. Reduction of left ventricular end-systolic and end-diastolic volume was significant in the chordal preservation groups (II and III) as compared to the nonchordal group (group I; p < 0.005). The total chordal group demonstrated greater fractional change of left ventricular end-systolic volume as compared to the posterior chordal and nonchordal group. The left ventricular ejection fraction and fractional shortening continued to decline over time in the nonchordal cohort (p = 0.05 and p = 0.001, respectively) and did not improve by 4 years. Statistically significant change in ejection fraction occurred in the chordal preservation groups as compared to the nonchordal group. CONCLUSIONS: We conclude that total chordal preservation is possible in the large majority of rheumatic patients and confers significant long-term advantage by preserving left ventricular function. The surgical technique should be individualized.

Adult↗
PubMed2005

Twenty-eight-year survival of stent-mounted aortic homograft in the mitral position: case report.

The case is presented of a long-term survivor after bioprosthetic valve implantation. A stent-mounted aortic homograft had been implanted in the mitral position, and survived for 28 years before being removed due to a tear in the base of leaflet, resulting in mitral regurgitation. The technique was discontinued in the mid- 1970s following reports of detachment of aortic valve cusps from the stent. The current case report may rekindle interest in the method, and also lead to an investigation of the factors that influence structural deterioration of bioprosthetic valves.

Aortic Valve↗
PubMed2004

Digital video recording of cardiac surgical procedures.

PURPOSE: We attempted to find a method of reducing time and effort for recording videos of cardiac surgical procedures. DESCRIPTION: A camera mounting arm designed by us provided a properly fixed digital camera location for undisturbed recording. The camera and its remote control unit provided an opportunity for the surgeon to record only the steps of the operation without need for editing. EVALUATION: Digital videos produced by this method required no additional time from the surgeon except to record the commentary at leisure. The video recorded was of excellent quality and provided a well-focused recording of the steps of the operation. CONCLUSIONS: The technique described for video recording of cardiac surgical procedures provides a time-saving and easy method for good reproduction of surgical procedures.

Cardiac Surgical Procedures↗
PubMed2004

Aortic valve replacement with 31- and 33-mm mechanical prostheses: early results.

The mean aortic diameter of Indian adults is 25-31 mm, yet fewer than 1% of worldwide heart valve procedures involve a 31-mm aortic heart valve. Of the 72 large prosthetic aortic valves (31-mm) implanted in the Asia Pacific region during 2001-2003, 53 (74%) were implanted at our institution. This retrospective study was undertaken to assess early results and outcomes, on echocardiography and exercise testing, in patients who received large prosthetic aortic valves. From January 1997 through December 2002, 27 patients underwent isolated aortic valve replacement with 31-mm St. Jude Medical prostheses, and 4 patients underwent aortic valve replacement with 33-mm St. Jude Medical reversed mitral prostheses. These 31 patients were among 240 who underwent isolated aortic valve replacement at our institution during the same period. The preoperative, perioperative, and postoperative data were collected from case records and patient follow-up. Fifteen of the 31 patients underwent echocardiography and exercise testing at least 6 months after operation. There were no early deaths. No patient developed prosthetic valve endocarditis or paravalvular leak. One patient, who developed valve thrombosis as a result of noncompliance with the anticoagulation regimen, underwent thrombectomy and died during the early postoperative period, due to low cardiac output. There was no structural failure or anticoagulant-related hemorrhage. Postoperatively, the peak and mean gradients across the prostheses were low. The exercise performance of all the patients was good. These early favorable results need to be borne out by longer and more comprehensive study of larger groups.

Adolescent↗
PubMed2004

Long-term results of cusp-level chordal shortening for anterior mitral leaflet prolapse.

The technique and early results of cusp-level chordal shortening for isolated anterior mitral leaflet prolapse in rheumatic mitral regurgitation were presented by us earlier. Here we present our experience from January 1989 through December 2000. Two hundred twenty-six patients underwent this procedure. The mean age was 18 +/- 7.22 years. Preoperatively, 38 (16.8%) patients were in New York Heart Association functional class 11, 160 (70.8%) were in class IIl, and 28 (12.4%) were in class IV. All patients underwent chordal shortening at the cusp level. In addition, 8 patients (3.5%) underwent chordal transfer, and 4 patients (1.8%) received neochordae. Two hundred twenty-one (97.8%) patients underwent posterior annuloplasty using a C-shaped polytetrafluoroethylene collar. In 85 (37.6%) patients, cuspal thinning was also performed. Early mortality was 3.5% (8 patients). Follow-up ranged from 1 to 144 months (mean, 53.02 +/- 31.10 months) and was 94% complete. In 68% of survivors, there was no or trivial mitral regurgitation. Ten patients required reoperation. There were 8 late deaths. Actuarial survival, mitral regurgitation-free survival, and event-free survival were 93.3% +/- 1.7%, 41.8% +/- 8.4%, and 73.6% +/- 6.6%, respectively. Among the 210 survivors, 159 (75.7%) were in New York Heart Association class I, 26 (12.4%) were in class II, 22 (10.5%) were in class III, and 3 (1.4%) were in class IV. We conclude that cusp-level chordal shortening for isolated anterior mitral leaflet prolapse is an effective procedure for correction of anterior mitral leaflet prolapse.

Adolescent↗
PubMed2003

The enantiomer of progesterone (ent-progesterone) is a competitive inhibitor of human cytochromes P450c17 and P450c21.

Human cytochrome P450c17 (17alpha-hydroxylase, 17,20-lyase) (CYP17) and cytochrome P450c21 (21-hydroxylase) (CYP21) differ by only 14 amino acids in length and share 29% amino acid identity. Both enzymes hydroxylate progesterone at carbon atoms that lie only 2.6A apart, but CYP17 also metabolizes other steroids and demonstrates additional catalytic activities. To probe the active site topologies of these related enzymes, we synthesized the enantiomer of progesterone and determined if ent-progesterone is a substrate or inhibitor of CYP17 and CYP21. Neither enzyme metabolizes ent-progesterone; however, ent-progesterone is a potent competitive inhibitor of CYP17 (K(I)=0.2 microM). The ent-progesterone forms a type I difference spectrum with CYP17, but molecular dynamics simulations suggest different binding orientations for progesterone and its enantiomer. The ent-progesterone also inhibits CYP21, with weaker affinity than for CYP17. We conclude that CYP17 accommodates the stereochemically unnatural ent-progesterone better than CYP21. Enantiomeric steroids can be used to probe steroid binding sites, and these compounds may be effective inhibitors of steroid biosynthesis.

Binding Sites↗
PubMed2002

Transaortic double valve replacement with total chordal preservation.

Very few cases of transaortic double valve replacement have been reported in the literature. A 26-year-old man presented to us with severe aortic regurgitation, mitral valve thickening, and mild mitral regurgitation 6 years after he had undergone a Ross procedure and open mitral commissurotomy. At his 2nd operation, he underwent transaortic double valve replacement with total chordal preservation of the mitral apparatus. Due to recurrent rheumatic activity, this patient had experienced a recurrence of valvulopathy Because we have observed this in other young patients with rheumatic heart disease, we no longer perform the Ross procedure in such patients, especially if there is associated mitral valve disease. In selected patients with dilated aortic annulus, the transaortic approach provides excellent access for safe mitral valve replacement with total chordal preservation. The surgical technique and a brief review of the literature are presented.

Adult↗
PubMed1992

Immunohistochemical and histochemical profile of Aschoff bodies in rheumatic carditis in excised left atrial appendages: an immunoperoxidase study in fresh and paraffin-embedded tissue.

We have evaluated the nature of Aschoff cells within Aschoff bodies seen in 35 of 100 excised left atrial appendages from cases of rheumatic mitral stenosis who underwent closed mitral valvotomy. These were tested using a panel of monoclonal and polyclonal antisera by the indirect immunoperoxidase staining for leucocyte common antigen, macrophage, desmin, vimentin, alpha-1-antitrypsin, alpha-1-antichymotrypsin, lysozyme, acid phosphatase and nonspecific esterase. The Aschoff cell gave strong reactivity with monoclonal antisera to vimentin, macrophage and variable reaction with polyclonal antisera known to recognise macrophages/histiocytes in tissues, namely alpha-1-antitrypsin, alpha-1-antichymotrypsin and lysozyme. These were also strongly positive for acid phosphatase and nonspecific esterase. The Aschoff cell lacked affinity for desmin and only an occasional cell in 4 out of 20 and 6 out of 35 cases showed a weak reaction with myoglobin and leucocyte common antigen, respectively. Intense consistent reactivity with several histiocytic markers affirms the genesis of these cells from macrophages/histiocytes and not muscle cells; a controversy which must be laid to rest!

Antibodies, Monoclonal↗