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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

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

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

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

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

Necrotic, ulcerative bronchitis, the presenting feature of lymphoproliferative disease following heart-lung transplantation.

Following heart-lung transplantation two of 21 patients who survived more than 100 days developed post-transplant lymphoproliferative disease. Both presented with localised ulcerative bronchitis documented at flexible bronchoscopy four months after transplantation. Histological examination showed necrosis with acute inflammation and ulceration. Case 2 demonstrated lymphoproliferative disease from biopsies subsequently taken at rigid bronchoscopy. Case 1 later developed lung nodules and a monoclonal high grade B cell non-Hodgkin's lymphoma was confirmed by an open lung biopsy. The bronchoscopic features described should alert clinicians to post-transplant lymphoproliferative disease as an underlying diagnosis and suggest that bronchus associated lymphoid tissue is the initial site for clonal proliferation in the disease.

Adult

Postpneumonectomy chylothorax.

Over a period of 22 years, chylothorax developed in 9 of 1,800 patients who underwent pneumonectomy. Two groups were identified. In group I (n = 5), accelerated opacification of the pneumonectomy space was noted, but the mediastinum remained shifted to the pneumonectomy site. No hemodynamic problems developed and their course was no different from that of other patients who had undergone pneumonectomy. In the second group (group II; n = 4), rapid opacification of the pneumonectomy space was accompanied by mediastinal shift away from the pneumonectomy site and by major hemodynamic and respiratory embarrassment. All 4 patients required surgical intervention to control the chylous leak.

Chylothorax

An alternative surgical technique in orthotopic cardiac transplantation.

Forty patients underwent orthotopic cardiac transplantation at Wythenshawe Hospital between May 1991 and November 1992. Twenty patients had transplantation using an alternative technique that preserves the shape of the left atrium and leaves the right atrium intact (group A). The remaining twenty had conventional transplantation using the technique described by Lower and Shumway (group B). The patients were randomized to either the new or the conventional technique on an alternate basis. There was no mortality in group A, but two patients in group B developed right ventricular failure and died. Two patients in each group developed nodal rhythm and all four recovered sinus rhythm. Echocardiography and Doppler velocimetry at the transvalvular level confirmed normal atrial function in group A with erratic atrial contraction wave in group B. There was also slightly lower incidence of mitral and tricuspid valve regurgitation in group A than in group B. The improved atrial function in group A may play a part in the prevention of right sided failure following cardiac transplantation.

Echocardiography

Regression of left ventricular hypertrophy in a transplanted heart.

A woman with advanced coronary artery disease underwent heart transplantation. The donor heart had left ventricular hypertrophy. The electrocardiographic and echocardiographic evidence, of left ventricular hypertrophy regressed during follow up; estimated left ventricular mass decreased from 393 g to 171 g. The adaptation of myocardial mass and performance after transplantation is not fully understood. This case illustrates the potential for regression of left ventricular hypertrophy in response to altered loading conditions.

Adaptation, Physiological

Coronary ostial stenosis: surgical considerations.

To investigate the clinical significance of coronary ostial stenosis, we reviewed eight patients with such lesions, including three with isolated stenosis at the orifice of the coronary artery. There were five male and three female patients, with an average age of 46.25 years (range 32-69 years). Their symptoms consisted mainly of angina (6 patients), with dyspnoea and palpitation being the presenting features in the remaining two patients. All patients underwent preoperative coronary angiography which confirmed stenosis at the level of the orifice with absence of reflux of contrast medium into the sinus of Valsalva as the main features. Delay in the appreciation of stenosis of the orifice of the right coronary artery resulted in the death of two patients, whose diagnosis was confirmed at post mortem examinations. Stenosis of the orifice of the right coronary artery was present in seven patients, with two patients also having stenosis of the orifice of the left coronary artery. The remaining patient had isolated stenosis of the left coronary arterial orifice. Coronary artery bypass grafting was performed in five patients, including two who had patch angioplasty to the right coronary artery. The patient with isolated stenosis of the orifice of the left coronary artery had patch angioplasty only. Follow-up of up to three years in the surviving patients showed good functional results. The ease with which it is possible to miss right coronary ostial stenosis is emphasized and angiographic features are reviewed.

Adult

Aortic valve replacement with combined myocardial revascularisation.

Early and late outcome was studied in 630 patients who underwent aortic valve replacement between 1974 and 1982. Group 1 (506 patients) did not have important coronary artery disease, group 2 (69 patients) had coronary artery disease and underwent coronary artery bypass grafting, and group 3 (55 patients) had coronary artery disease but did not undergo myocardial revascularisation. Early mortality (within 30 days of operation) was significantly lower for group 1 (6%) than for group 2 (13%) and for group 3 (16%). Operative mortality in all three groups was lower in patients operated on more recently. The three year survival of patients in group 1 (83%) was significantly higher than that of patients in group 3 (62%) but not than that of patients in group 2 (76%). The findings of this study suggest that the presence of coronary artery disease increases the risk of aortic valve replacement whether or not coronary artery grafting is performed. Myocardial revascularisation, however, seems to return patients with aortic valve and coronary artery disease to a survival curve similar to that of patients with isolated aortic valve disease.

Actuarial Analysis

Actuarial analysis of late results after closed mitral valvotomy.

The long-term results of closed mitral valvotomy performed between 1978 and 1985 in 198 patients with noncalcific mitral stenosis were analyzed. Follow-up data were available on 185 patients (93%); 1 patient died in the postoperative period, and 12 foreign patients were lost to follow-up. At the 4-year and 8-year intervals, 91% and 80% of patients, respectively, were event free (not in need of further operative procedures). By multivariate analysis, the factor preoperative mild mitral regurgitation showed a tendency to influence the event-free period. By univariate analysis, postoperative mitral regurgitation significantly reduced the event-free period. Twenty-one patients subsequently underwent mitral valve replacement; 8 for mitral regurgitation, 10 for mitral stenosis, and 3 for mixed mitral regurgitation and stenosis. By multivariate analysis, the reason for reoperation significantly influenced the length of the event-free period. The patients with mitral regurgitation required mitral valve replacement sooner than those with mitral stenosis. Advanced age, sex, previous valvotomy, preoperative New York Heart Association Functional Class, low mitral valve leaflet excursion, and pulmonary hypertension had no influence on the long-term result.

Actuarial Analysis

Infection of cardiac mural thrombus associated with left ventricular aneurysm.

Infection is a rare complication of cardiac mural thrombus and may prove difficult to diagnose and treat. We describe a patient with infected thrombus associated with a left ventricular aneurysm, involving Salmonella typhimurium. Cross-sectional echocardiography proved helpful in establishing the diagnosis.

Echocardiography