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Biomedical subjects

A N Rahman

Publications and source records attributed to A N Rahman.

At least 19 recordsLinked to original sources
PubMed2001

Cardiac transplantation for cardiomyopathy and ischemic heart disease: differences in outcome up to 10 years.

BACKGROUND: Ischemic heart disease (IHD) and cardiomyopathy (CM) are the most common indications for heart transplantation. The aim of this study was to investigate the difference in clinical outcome between these two groups. METHODS: At our institution between 1987 and 1998 transplantation was performed in 133 patients with IHD and 87 with CM. Follow-up was complete for all patients (mean 87 months). RESULTS: Mean age at time of surgery was 51 +/- 5 years for IHD versus 39 +/- 9 years for CM recipients (p = 0.02). There was no difference in donor age, donor gender, or pre-operative hemodynamics between the two groups. The operative mortality was 11.2% in IHD recipients and 10.6% in CM recipients (p = 0.9). No differences were observed in intra-cardiac pressures or incidence of renal dysfunction, infection, or malignancy between the two groups. The incidence of peripheral vascular incidents was significantly higher for IHD recipients (13% vs 3%, p = 0.02). At 10 years, the incidence of coronary artery disease was 35% and 9%, respectively (p = 0.02). Mean NYHA status was 2.0 +/- 0.3 and 1.1 +/- 0.2 for IHD and CM recipients, respectively (p = 0.013). The actuarial survival at 1, 5, and 10 years was 77%, 62%, and 39% for IHD recipients compared with 85%, 82%, and 80% for CM recipients (p = 0.7, p < 0.0001 and p < 0.0001, respectively). CONCLUSION: After heart transplantation, medium- and long-term outcome is significantly better for CM than IHD recipients. In view of limited donor availability, it is appropriate to explore more vigorously alternative treatments for patients with severe ischemic left ventricular dysfunction.

Adult↗
PubMed1999

The influence of histocompatibility on graft rejection and graft survival within a single center population of heart transplant recipients.

BACKGROUND: We report a consecutive single center series of 261 patients who received first orthotopic heart transplants from 1986 to 1997. The 1- and 5-year graft survivals were 78 and 68%. The influence of histocompatibility was investigated by comparing graft survival and numbers of treated rejection episodes with HLA-A, -B, and -DR mismatches over different time periods. FINDINGS: Recipients with six mismatches for HLA-A+-B+-DR combined (13.4%) had reduced survival at 7 years (47%) when compared with other recipients (64%). In the first year of transplant, recipients with four HLA-A+-B mismatches had significantly reduced actuarial graft survival (P=0.03) with the greatest influence apparent at 6 months [0-3 mismatches (n=193) 85% versus 4 mismatches (n=68) 69%; P=0.005, OR=2.1]. For 182 recipients with functioning hearts at 1 year, the number of rejection episodes treated within this time was strongly influenced by HLA-DR mismatch [0 DR mismatch (n=15) mean 1.2 rejection episodes versus 1 DR mismatch (n=76) mean 2.7 rejection episodes versus 2 DR mismatches (n=91) mean 3.8 rejection episodes: P=0.0002]. Of these 182 transplants, recipients who had more than four treated rejection episodes during the first year had a significantly reduced 7- year survival [<5 rejection episodes (n=133) 85% versus more than four rejection episodes (n=49) 66%; P=0.02, OR=3.4], as did those with two HLA-DR mismatches [0+1 mismatch (n=91) 87% versus 2 mismatches (n=91) 70%; P<0.05, OR=2.4]. INTERPRETATION: We show that graft loss in the first 6 months of transplant is significantly influenced by four HLA-A+-B mismatches. HLA-DR mismatch significantly increases the number of rejection episodes within the first year, without influencing graft survival. After 12 months both >4 rejection episodes in the first year and two HLA-DR mismatches are markers for late graft loss. We postulate that immunological graft loss in the first 6 months is dominated by the direct allorecognition pathway driven by HLA-DR mismatch. This mechanism is later lost or suppressed. Our data highlight HLA-DR mismatch as a marker for late graft loss and we show an advantage to avoiding transplanting hearts with six HLA-A+-B+-DR mismatches and to minimizing HLA-DR mismatches whenever possible.

Adolescent↗
PubMed1999

Risk factors for tricuspid valve regurgitation after orthotopic heart transplantation.

BACKGROUND: Tricuspid regurgitation (TR) may occur following orthotopic heart transplantation (OHT) and although a number of etiological factors have been suggested, the relative contribution of each of these remains to be elucidated. We aimed to assess the risk factors for TR in our 10-year experience of orthotopic heart transplantation (OHT). METHODS: OHT was performed in 249 patients (161 by the standard technique and 88 by the bicaval technique). TR was assessed using transthoracic color Doppler echocardiography. RESULTS: Recipients who underwent operation by the standard technique displayed higher incidence of moderate and severe TR than did bicaval-technique recipients. The development of early TR was also correlated to rejection greater than or equal to grade 2, preoperative raised transpulmonary gradient, and raised pulmonary vascular resistance. Risk factors for late TR were standard technique (p < 0.0001), number of rejection greater than or equal to grade 2 (p < 0.004), and the total number of heart biopsies (p < 0.02). Recipients with moderate and severe TR revealed elevated right-side pressures and advanced New York Heart Association statues compared to those with no, trivial, or mild TR. CONCLUSIONS: Various factors contribute to TR after OHT, the prevalence of which might be lowered by adopting the bicaval technique, early treatment of rejection, and reduction of the number of biopsies performed.

Adolescent↗
PubMed1999

Orthotopic cardiac transplantation technique: a survey of current practice.

BACKGROUND: The Lower and Shumway technique has been the gold standard for orthotopic heart transplantation (OHT) for the past 35 years. In the last decade the bicaval and total techniques have been introduced but it is unclear how these alternative techniques have influenced the current surgical practice of OHT. METHODS: A worldwide survey of 210 International Society of Heart and Lung Transplantation centers was conducted by questionnaire: 169 replies were received; a response rate of 80%. RESULTS: Seventy-four centers (44%) use a combination of more than one technique with the remaining centers (n = 95 centers) employing one technique exclusively. The bicaval technique is the most frequently used technique in the majority of transplant procedures in 92 (54%) centers. In only 38 centers (22%), the standard technique was the most frequently employed technique. The total technique was the choice in 8 centers (5%). The maximum acceptable ischemic time varied from 3 to 9 hours with a median of 5.7 hours. Only 92 centers (54%) do not use cardioplegia during implantation. CONCLUSIONS: Since its introduction, the bicaval technique has become the most commonly used procedure for OHT. The long-term advantage of right atrial preservation with the bicaval technique will require further studies.

Cross-Cultural Comparison↗
PubMed1999

Heart transplantation for peripartum cardiomyopathy: a report of three cases and a literature review.

Peripartum cardiomyopathy is a devastating medical condition and carries a mortality of up to 60% with medical treatment. The authors describe their experience of successful outcome of three cases with heart transplantation and review the literature. The importance of performance of endomyocardial biopsy for all peripartum cardiomyopathy patients is emphasized. It is recommended that heart transplantation should only be offered to myocarditis negative patients.

Adult↗
PubMed1997

Significance of raised natriuretic peptides after bicaval and standard cardiac transplantation.

BACKGROUND: High levels of plasma atrial natriuretic peptide (ANP) and ventricular natriuretic peptide (BNP) have been identified after standard orthotopic cardiac transplantation. It has been postulated that the high ANP levels are a result of persistent secretion from the large residual atrial mass after transplantation. This study was undertaken to investigate the significance of raised ANP and BNP levels after standard and bicaval orthotopic heart transplantation. METHODS: Plasma ANP and BNP levels were measured in 40 ambulatory, randomly selected cardiac transplant patients (group A, n = 20 had bicaval transplantation; group B, n = 20 had standard transplantation) and 10 healthy volunteers (group C). Cardiac transplant patients underwent endomyocardial biopsy and hemodynamic evaluation. RESULTS: Plasma levels of ANP and BNP were elevated in the transplant recipients in comparison with normal volunteers (p = 0.0001 and p < 0.0001, respectively). There was no significant difference in the ANP levels between group A and group B, whereas BNP levels were higher in group B compared with group A (p = 0.03). Linear regression analysis showed that a faster heart rate, high mean pulmonary artery pressure, high pulmonary capillary wedge pressure, and high transpulmonary gradient were associated with higher levels of BNP (p < 0.05). Lower mean systemic pressure was associated with higher levels of ANP (p < 0.05). CONCLUSIONS: High levels of ANP and BNP are synthesized and secreted by the transplanted denervated human heart regardless of the surgical technique. The level of BNP correlates with ventricular performance and afterload. The bicaval technique seems to be associated with better left ventricular and right ventricular diastolic performance.

Adult↗
PubMed1996

Pulmonary interstitial fibrosis and haemosiderin-laden macrophages: late following heart transplantation.

Impairment of pulmonary diffusion is recognized following heart transplantation. This study was undertaken to determine the histopathological basis for the defect in pulmonary physiology. Heart transplant recipients (HTR) entered into a prospective study of post-transplant pulmonary physiology were asked to undergo bronchoscopy, bronchoalveolar lavage (BAL) and transbronchial biopsy (n = 18) in the presence of impaired gas transfer. Transbronchial biopsies were examined under light microscopy and demonstrated focal interstitial fibrosis in 12 patients, cytomegalovirus disease in four patients and Pneumocystis carinii pneumonia in three patients. Bronchoalveolar lavage differential counts were normal in HTR but BAL macrophages contained haemosiderin. The histological features of interstitial fibrosis may underlie the fall in gas transfer seen following heart transplantation. The presence of haemosiderin-laden macrophages late following heart transplantation suggests a capillary leak syndrome.

Bronchoalveolar Lavage↗
PubMed1996

Epstein-Barr virus associated graft failure following heart/lung transplantation.

A case is described of late pulmonary graft failure in a heart/lung transplant recipient. The major characteristics were alveolar fibrosis and a restrictive physiological deficit. Epstein-Barr virus was implicated as an aetiological agent using immunohistochemical analysis and by a response to treatment with ganciclovir.

Adult↗
PubMed1996

Pulmonary diffusion impairment following heart transplantation: a prospective study.

The aim of this prospective study was to confirm whether and when a fall in gas transfer occurs following heart transplantation (HT); and to examine the potential relationship between gas transfer and haemodynamic change, immuno-suppression and cytomegalovirus (CMV) infection. The lung physiology of 34 heart transplant recipients (HTR) and 14 control patients undergoing coronary artery bypass grafting (CABG) were studied. The absolute and standardized residual values of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), residual volume (RV), forced residual volume (FRC), total lung capacity (TLC), transfer factor of the lungs for carbon monoxide (TL,CO) and carbon monoxide transfer coefficient (KCO) were measured before and at 30, 60, 90, 120 and 150 days after HT. These data were compared to haemodynamic status, graft rejection, cyclosporin levels and episodes of CMV infection. Lung function was studied in a group of patients before and 4 weeks after CABG. There was a significant fall in mean KCO after HT (pre-HT = 1.29 and post-HT = 1.06 mmol.min-1.kPa.L-1) but not after CABG (pre-CABG = 1.49, post-CABG = 1.5 mmol.min-1.kPa.L-1. No relationship was observed between gas transfer and CMV. At the latest stage following HT (150 days) there was a positive correlation between TL,CO (absolute value and standardized residual) and mean cyclosporin level (r = 0.48 and r = 0.44, respectively) and also between the absolute KCO and actual (r = 0.56) and mean (r = 0.55) cyclosporin levels. Following HT, there is an early fall in gas transfer, which is independent of the effects of surgery and bypass, implicating early immunosuppression (e.g. antithymocyte globulin/cyclosporin).

Coronary Artery Bypass↗
PubMed1996

Orthotopic heart transplantation hemodynamics: does atrial preservation improve cardiac output after transplantation?

BACKGROUND: We have described an alternative technique for orthotopic heart transplantation (bicaval Wythenshawe technique) which maintains the right and left atrial anatomy and contractility. METHODS: Fifty patients were randomized into two groups: group A (n = 25) who had orthotopic heart transplantation using the bicaval Wythenshawe technique and group B (n = 25) who had conventional (Lower and Shumway) technique of orthotopic heart transplantation. We compared the cardiac output (measured by thermodilution technique) with atrial activation (AAI pacing) to cardiac output without atrial activity (VVI pacing) in both groups to identify any beneficial hemodynamic effects. All patients were studied the first and second weeks after transplantation. The inaccuracies of comparing cardiac output measurements caused by different loading conditions, inotropic state, and systemic vascular resistance were eliminated by using the patient as his or her own control. RESULTS: The difference between the measured cardiac output with atrial pacing and ventricular pacing was 1.42 +/- 0.44 L/min in group A in comparison with 0.32 +/- 0.4 L/min in group B (p = 0.001 Wilcoxon signed rank). The percentage of atrial contribution to the cardiac output in group A was 30% +/- 12% (standard deviation), 95% confidence interval in comparison with 7% +/- 9%, 95% confidence interval in group B. The mean stroke volume in group A was higher in sinus rhythm (65 +/- 19.2 ml) and atrial pacing (62 +/- 17.7 ml) compared with ventricular pacing (49.17 +/- 16.43 ml) p = 0.001. In group B no statistical difference was found between stroke volume measured with atrial (47.71 +/- 6.23 ml) or ventricular pacing (46.9 +/- 6.35 ml). CONCLUSIONS: We conclude that the bicaval technique of orthotopic heart transplantation preserve the atrial kick and its contribution to cardiac output early after transplantation.

Atrial Function↗
PubMed1996

Solitary thyroid nodule: a study of 100 cases.

One hundred cases of solitary thyroid nodules attending the thyroid clinic, Institute of Postgraduate Medicine & Research, Dhaka (IPGMR) and the Institute of Nuclear Medicine (INM) were included in a prospective study. Thyroid ultrasonography (USG), scintiscanning, radioactive iodine (I131) uptake (RAIU), estimation of serum total T3, T4 & TSH and Fine Needle Aspiration Cytology (FNAC) were performed in all cases. Surgical resection with histopathologic study was performed in selected cases. Extra-nodular part of the thyroid gland was normal in 68 and diffusely enlarged in 32, RAIU was normal in 62, high in 36 and very low in two subjects. Nodules were solid at USG in 67 subjects, cystic in 16 subjects and of mixed consistency in 17 subjects. Goitrous subjects had significantly lower T4 (p < 0.001) and higher T3 (p < 0.01) and TSH (p < 0.001) than non-goitrous ones. Colloid nodule was the commonest pathology occurring in 41 cases, followed by thyroid cysts (26), follicular adenoma (23), adenoma with cystic change (7), subacute thyroiditis (2) and papillary carcinoma (1). Colloid nodules were more common in goitrous subjects which could hint at iodine deficiency as the major cause of such nodules. Hyperfunctioning follicular adenomas occurred exclusively in non-goitrous subjects. Carcinoma appeared to be uncommon in patients with solitary nodules. It gives an opportunity to our physicians to be more conservative in selecting patients with solitary thyroid nodules for surgical treatment.

Adenoma↗
PubMed1995

Right lower lobe herniation after domino heart-lung transplantation.

We report 2 cases of trapping and incarceration of the right lower lobe in the left hemithorax after heart-lung transplantation with bicaval anastamoses (domino donors). This occurred despite confirmation of the normal anatomy at the time of implantation, before lung inflation. In 1 case this complication resulted in a right lower lobectomy 7 days after transplantation due to infarction and infection of the right lower lobe. These cases illustrate the importance of reexamining the anatomy after lung inflation, before chest closure.

Adult↗
PubMed1995

Orthotopic cardiac transplantation: a comparison of standard and bicaval Wythenshawe techniques.

We describe an alternative technique for orthotopic cardiac transplantation (bicaval Wythenshawe technique), which maintains the right and left atrial anatomy. We compared the new bicaval technique with the conventional (Lower and Shumway) technique of orthotopic cardiac transplantation to identify any beneficial physiologic and clinical outcomes resulting from maintaining the normal anatomy. Seventy-five patients were randomized on an alternate basis to two groups: group A (n = 40) had orthotopic cardiac transplantation with the bicaval technique and group B (n = 35) had conventional orthotopic heart transplantation. All patients were studied with transthoracic echocardiogram, endomyocardial biopsies, and measurement of intracardiac pressures 1, 4, and 12 weeks after transplantation. There were no statistically significant differences in the demographic profile, ischemic time, bypass time, implantation time, transpulmonary gradient, or pulmonary vascular resistance between the two groups. The hemodynamic data were collected in the absence of histologic signs of rejection. In group A right atrial pressure (mean 3.6 mm Hg) was significantly lower (p < 0.03) than in group B (mean 8.8 mm Hg). The right atrial a wave was recorded in 38 patients in group A compared with seven patients in group B (p = 0.041). Atrial tachyarrhythmias occurred in two patients in group A compared with 11 in group B (p < 0.016). Temporary pacing was required in 10 patients in group A and 16 patients in group B (p = 0.034). Four cases of mitral regurgitation (all mild) were detected in group A in comparison with 12 cases (10 mild, 2 severe) in group B (p = 0.008). The mean ejection fraction in the first week after transplantation was 58% in group A and 46% in group B (p = 0.5). In the first 3 months the need for diuretics was less in group A (mean dose 80.8 mg furosemide daily) than in group B (mean dose 134 mg furosemide daily in the first week increasing to 160 mg furosemide daily). Hospital stay was shorter in group A (mean 23 days) than in group B (mean 27 days) (p < 0.015). There were no early deaths as a result of right ventricular failure in group A (n = 0/40) compared with four (n = 4/35; 9%) in group B (p < 0.034). This difference suggests that bicaval orthotopic cardiac implantation is associated with a lower right atrial pressure, a lower likelihood of atrial tachyarrhythmias, less need for pacing, less mitral incompetence, a lower diuretic dose, and a shorter hospital stay.(ABSTRACT TRUNCATED AT 400 WORDS)

Echocardiography↗
PubMed1995

Detection of human cytomegalovirus antigenaemia: a rapid diagnostic technique for predicting cytomegalovirus infection/pneumonitis in lung and heart transplant recipients.

BACKGROUND: New rapid diagnostic techniques offer the opportunity of early diagnosis of human cytomegalovirus (CMV) infection in immunocompromised patients at risk of developing CMV disease. The use of human CMV antigenaemia as a predictor of clinical CMV infection and disease in lung and heart transplant recipients was studied prospectively. METHODS: Twenty three heart and nine lung transplant recipients who survived 40 days were observed by standard CMV surveillance with serological testing, culture, and by sequential testing for CMV antigenaemia. CMV antigenaemia testing is a rapid and quantifiable technique in which a viral lower matrix protein is detected in cytospin preparations of peripheral blood polymorphonuclear leucocytes (PMNLs) by immunofluorescent staining. RESULTS: Eleven patients developed CMV infection and five developed CMV disease (four pneumonitis, one duodenitis). These clinical events occurred at a median of 65 days following transplantation. CMV antigenaemia occurred in 17 patients at a median of 35 days following transplantation. Detection of CMV antigenaemia had a sensitivity of 100%, a specificity of 93.7%, and a positive predictive value of 94.1% for CMV related illness. CMV antigenaemia was positive at a significant interval before the clinical event. High levels of CMV antigenaemia (> 50 CMV antigen positive cells/2 x 10(5) PMNLs) occurred in 11 patients and five of these developed disease. CMV antigenaemia of > 50 CMV antigen positive cells/2 x 10(5) PMNLs had a positive predictive value of 45.5% for disease but a negative predictive value of 100%. Patients with disease had higher levels of antigenaemia than those without disease. CONCLUSIONS: CMV antigenaemia is a rapid diagnostic technique which can identify patients likely to develop CMV disease, potentially allowing early treatment.

Antigens, Viral↗