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Biomedical subjects

S R Large

Publications and source records attributed to S R Large.

84 records · Page 5Linked to original sources
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Radiological evaluation of the ascending aorta following repair of type A dissection.

A patient with persistent chronic dissection proximal to an aortic interposition graft for repair of a type A dissection prompted us to review the computed tomographic (CT) findings in 14 other such patients 5-47 months after surgery. No other case of proximal aortic dissection was identified although dilatation of the aortic root proximal to the graft was present in 8 patients (57%). Persistent dissection distal to the graft in 11 patients (79%) was in keeping with that reported by other workers. Chronic dissection proximal to the surgical repair of a dissection seems a rare although important complication.

Aortic Dissection↗
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Preservation, reperfusion, and rejection in transgenic xenograft organs.

The success of transplantation has resulted in increasing demand, despite a continuing fall, in donor organ supply. This widening gap encourages the argument for animals to act as a reservoir for donor organs (xenografts). Despite genetic manipulation, transgenic xenograft organs are at risk of vascular rejection in man (delayed xenograft rejection), a process in part involving endothelial cell activation. It appears that ischemia-reperfusion injury also involves endothelial cell activation. Evidence already exists to support the suggestion that ischemia-reperfusion injury may promote delayed xenograft rejection. The mechanisms of both these processes are briefly described and a case is made for optimum organ preservation of transgenic xenograft donor organs before clinical work is proposed.

Animals↗
PubMedDate not supplied

Influence of recipient and donor gender on outcome after heart transplantation.

To investigate the effect of recipient and donor genders on the outcome after heart transplantation, a retrospective survey was undertaken of 356 patients (366 transplants: 316 males, 40 females) undergoing transplantation between January 1979 and December 31, 1989, at Papworth Hospital. Ninety-three organs came from female donors; 263 organs came from males. Twelve females (30%; 95% confidence interval 16% to 44%) and 51 males (16%; 95% confidence interval 12% to 20%) died in the early postoperative period (within 90 days of operation). To date, two females (5%) and 51 males (16%) have died in the late postoperative period. Comparison between recipient genders showed no statistically significant difference in early mortality rates from any cause or in actuarial survival overall, although fatal acute rejection was significantly more common in female recipients (7 of 40 female recipients versus 19 of 316 male recipients). The higher incidence of fatal rejection among female recipients was related to the higher proportion of female donors in this group, because recipients of female donor grafts had significantly higher mortality rates, particularly in the early postoperative period and as a result of acute rejection, than did recipients of organs from male donors. Death from rejection after the first 3 months and death from infection were not gender-related. Recipients of grafts from female donors did not suffer significantly more early morbidity, such as rejection and infection, or late morbidity in the form of coronary artery disease. Acute rejection episodes were more common in female recipients.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
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Aorto-pulmonary fistula: a rare acquired lesion.

Rupture of thoracic aortic aneurysms usually result in death from tamponade. Rarely does fistulous formation between the aorta and pulmonary artery complicate rupture. Such a complication results in the development of an acute left to right shunt. Although many previous reports occur in the literature only 10 include surgical management of an acquired aortic-pulmonary fistula. Two cases are presented with a description of their surgical management and outcome. Both these patients had previously undergone aortic valve replacement in the distant past for aortic regurgitation. These were the only 2 cases found in a review of 890 aortic valve replacements in Papworth Hospital over a 10 year period from 1975. The sicker of the two patients died during the operation and the second made a prompt recovery, succumbing a few years later to a cerebro-vascular accident.

Aged↗
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Transforming the "unacceptable" donor: outcomes from the adoption of a standardized donor management technique.

BACKGROUND: Donor management remains one of the most neglected areas of transplantation. A comprehensive donor management regimen has been developed. The results of the application of this strategy form the basis of this report. METHODS: Full hemodynamic data were collected from 150 multiorgan donors between October 1990 and August 1993. The data were collected at the time of donor team arrival, after insertion of a pulmonary artery floatation catheter and immediately before cardiac excision. RESULTS: Fifty-two donors (35%) fell well outside our minimum acceptance criteria on arrival. Twenty-one of fifty-two had a mean arterial pressure less than 55 mm Hg (mean 47 mm Hg) despite inotropic support in most cases; 10 of 52 had a central venous pressure greater than 15 mm Hg (mean 18.0 mm Hg); 2 of 52 had a high inotrope requirement greater than 20 micrograms/kg/min (mean 25 micrograms/kg/min). After the insertion of a pulmonary artery floatation catheter, an additional 13 of 52 donors were found to have a pulmonary capillary wedge pressure greater than 15 mm Hg (mean 19.8 mm Hg), and the final 6 of 52 had a low left ventricular stroke work index, less than 15 gm (mean 12.8 gm). After optimal management, including hormone replacement 44 of 52 donors yielded transplantable organs (29 hearts, 15 heart and lung blocks). Thirty-seven of forty-four patients (84%) were alive and well from 13 to 48 months after transplantation. There were five early deaths (11%) caused by infection (heart), adult respiratory distress syndrome (heart), arrhythmia (heart), cerebrovascular event (heart and lung), and infection (heart, lung, and liver). Two late deaths (5%) occurred as a result of tamponade (3 months, heart) and infection (14 months, heart and lung). Eight of fifty-two organs were still unsuitable for transplantation after optimum management during the splanchnic dissection as a result of inotrope dependency (n = 4), left ventricular hypertrophy (n = 2), and coronary artery disease (n = 2). CONCLUSIONS: The data indicate that, of the organs which initially fall outside our transplant acceptance criteria, 92% are capable of functional resuscitation. Conversely, superficial assessment may not show compromised function. Optimizing cardiovascular performance also has important implications for the viability of all transplantable organs. This aggressive approach to donor management has resulted in the transplantation of 44 donor hearts that may otherwise have been turned down or inappropriately managed.

Adult↗
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Cardiac transplantation--the next decade.

Cardiac transplantation has developed at an extraordinary rate in its 26-year history and this article addresses the possible directions that we can expect of it in the remaining years of this decade. It currently offers a very effective therapeutic option for those with refractory heart failure but still carries significant risks.

Forecasting↗
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Heart transplantation in the United Kingdom: who waits longest and why.

BACKGROUND: This study aims to identify characteristics that increase the chance of death of potential cardiac transplant recipients before donor organs become available. METHODS: Between June 1, 1988, and May 31, 1993, 332 patients were accepted for heart transplantation; 235 underwent surgery. Ninety-seven patients had not received transplants; of these, 71 died, 13 were transferred to other lists, and 13 were awaiting organs at the close of the study. Median waiting time for those patients who received organs was 109 days, whereas patients who did not receive organs spent a median of 94 days on the list. Recipients are matched to donor organs according to blood group, size (height), and, recently, preoperative transpulmonary pressure gradient. Recently cytomegalovirus antibody mismatches (positive donor to negative recipient) have been avoided where possible. These factors, together with age, gender, underlying diagnosis, previous heart surgery, and Toxoplasma antibody status were studied to assess their influence on waiting time and survival. RESULTS: No characteristics were found significantly to influence survival after acceptance, so that the chance of death while the patient was waiting for heart transplantation is mainly affected by the severity of disease and the length of time a patient waits. In multivariate analyses the following were independently significantly associated with shorter waiting times: small patients (< 1.7 m tall; p = 0.005), patients with blood types B and AB (p = 0.003), and patients with cardiomyopathy (p < 0.001). CONCLUSIONS: These results can be used by cardiologists to help assess the time at which a patient should be referred for transplantation.

Blood Grouping and Crossmatching↗
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Domino heart transplantation: the Papworth experience.

The use of donor hearts from heart-lung recipients, the so-called domino procedure, began at Papworth Hospital in November 1988. Between then and September 1992, 198 heart transplantations and 86 heart-lung transplantations were performed. Fifty-three heart-lung recipients donated their hearts for use in the domino procedure. Thirty-two domino hearts were transplanted at Papworth and 21 were exported to other centers. Institution of the domino procedure allowed us to perform 19% more heart transplantations (166 to 198) than would have been done had the procedure not been used. The ischemic time was significantly shorter for the domino hearts compared with organs from brain dead donors (134 minutes versus 191 minutes; p < 0.001). No difference was found in the 3-month (84% versus 83%) or 1-year (74% versus 76%) survival between domino and nondomino recipients. Other potential advantages of the domino procedure include detailed pretransplantation evaluation of the heart in live donors and the potential for human leukocyte antigen matching. Additionally many heart-lung recipients have elevated pulmonary artery pressures and a "conditioned", hypertrophied right ventricle. The use of such hearts for heart transplantation has theoretic appeal for patients with elevated pulmonary vascular resistance.

Actuarial Analysis↗
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A method of analyzing the onset and progression of coronary occlusive disease after transplantation and its effect on patient survival.

The development of transplant-acquired coronary occlusive disease is monitored with serial angiography and is graded on a three-point scale as normal, mild (< 50% stenosis), or severe (> or = 50% stenosis). Previous studies have provided information about the time to the first sign of disease on angiography or empirical descriptions of progression. The number of observed transitions between grades of disease has been recorded, and a Markov model based on these transitions is used to estimate the rate of progression through angiographically defined disease grades and the mortality rates from each grade. Five hundred thirty-six angiograms from 240 patients were analyzed. Fifty-three graft failures occurred. The annual transition rate per patient year from normal to mild disease was low, 0.120 (95% credible interval, 0.096 to 0.154), although the transition from mild to severe disease was relatively high, 0.482 (95% credible interval, 0.325 to 0.671). Annual death rates from normal, mild, and severe grades were 0.032 (95% credible interval, 0.016 to 0.052), 0.076 (95% credible interval, 0.007 to 0.187) and 0.415 (95% credible interval, 0.244 to 0.640), respectively. Before onset of disease patients have a hazard-free course, and mild disease displayed on angiography is relatively non-life-threatening. However, once mild disease has been detected by angiography, progression to severe disease is rapid, and severe disease carries a very poor prognosis.

Adolescent↗
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Lack of association between endomyocardial evidence of rejection in the first six months and the later development of transplant-related coronary artery disease.

The development of transplant-related coronary artery disease (TCAD) is the major determinant of long-term heart transplant survival. To test the hypothesis that TCAD might be related to cellular myocardial rejection, the grades of rejection seen at all biopsies performed in the first 6 months after heart transplantation were analyzed in 108 patients who survived more than 6 months. The development of TCAD was assessed at routine follow-up coronary angiography in 101 patients and at necropsy in seven patients. This data was analyzed with Kaplan-Meier survival curves and Cox proportional hazard regression analysis. No significant association was found between either moderate rejection or any level of rejection and the later development of TCAD, nor did the absence of any rejection protect against its development.

Biopsy, Needle↗