Biomedical subjects
P Hornick
Publications and source records attributed to P Hornick.
Coronary artery bypass grafting in non-dialysis-dependent mild-to-moderate renal dysfunction.
OBJECTIVES: The effect of mild-to-moderate elevation of preoperative serum creatinine levels on morbidity and mortality from coronary artery bypass grafting has not been investigated in a large multivariable model incorporating preoperative and intraoperative variables. Our first objective was to ascertain the effect of a mild-to-moderate elevation in the preoperative serum creatinine level on the need for mechanical renal support; the duration of special care and total postoperative stay; the occurrence of infective, respiratory, and neurologic complications; and hospital mortality. Our second objective was to ascertain which patient variables contributed to an increase in the serum creatinine level in association with coronary artery bypass grafting. METHODS: A total of 1427 patients who had no known pre-existing renal disease and who were undergoing first-time coronary artery bypass grafting with cardiopulmonary bypass were recruited for the study. Patients were divided, on the basis of preoperative serum creatinine level, into 3 groups as follows: creatinine level of less than 130 micromol. L(-1); creatinine level of 130 to 149 micromol. L(-1); and creatinine level of 150 micromol. L(-1) or greater. A multivariable stepwise logistic regression analysis was used, and variables significant at the 5% level were included when developing the final multivariable models. RESULTS: Multivariable analysis showed that elevation of the preoperative serum creatinine level to 130 micromol. L(-1) or greater increased the likelihood of needing mechanical renal support postoperatively (P <.001), as well as the need for postoperative special care (P <.001) and total hospital stay (P <.001). In-hospital mortality was also significantly elevated as the preoperative creatinine level rose to 130 to 149 micromol. L(-1) (P =.045) and to 150 micromol. L(-1) or greater (P <.001). It was further observed that patients with preoperative serum creatinine levels of 130 to 149 micromol. L(-1) (P =.02), patients with preoperative serum creatinine levels of 150 micromol. L(-1) or greater (P =.001), hypertensive patients (P =.007), patients with angina of New York Heart Association class III or greater (P =.001), patients having a nonelective operation (P =.002), and patients having a prolonged cardiopulmonary bypass time (P =.008) had a significantly greater increase in the serum creatinine level as a result of coronary artery bypass grafting. Of particular note was the finding that the method of myocardial protection (cardioplegia or crossclamp fibrillation) did not significantly influence in-hospital mortality, need for mechanical renal support, or special care or total postoperative hospital stay. CONCLUSIONS: A mild elevation (130-149 micromol. L(-1)) in the preoperative serum creatinine level significantly increases the need for mechanical renal support, the duration of special care and total postoperative stay, and the in-hospital mortality. As the preoperative serum creatinine level increases further (> or =150 micromol. L(-1)), this effect is more pronounced. No significant difference in outcome was observed between the use of cardioplegia or crossclamp fibrillation for myocardial protection.
Role of donor and recipient antigen-presenting cells in priming and maintaining T cells with indirect allospecificity.
BACKGROUND: It has been suggested that the sensitization of recipient T lymphocytes against peptides derived from allogeneic major histocompatibility complex (MHC) antigens in the context of self-MHC molecules may contribute to the pathogenesis of chronic allograft rejection. The purpose of this study was to quantitate and characterize the indirect alloresponse in renal transplantation. METHODS: An HLA-A2-negative patient whose A2-positive kidney transplant failed as a result of chronic rejection was selected for this study. T-cell clones were raised using a cocktail of peptides corresponding to polymorphic regions of the A2 sequence and studied by measuring their proliferation using [3H]thymidine incorporation. The presence in vivo of HLA-A2-specific T cells was assessed using limiting dilution analysis. RESULTS: T-cell clones were specific for a single peptide of HLA-A2, residues 92-120, and restricted by HLA-DRB1*1502. The frequency of interleukin-2-secreting T cells specific for this A2 peptide was 1:86,000, only 2-fold lower than that measured against the recall antigen tetanus toxoid. Capitalizing on the similarity of the donor and recipient DR15 alleles (DRB1*1501 and 1502), the question was addressed as to how these T cells had been primed in vivo. Although the large majority of clones responded to A2 synthetic peptide presented by both DR15 alleles, only 3 of 10 clones responded to cells co-expressing DRB1*1501 and A2. CONCLUSION: These data suggest that antigen presentation by recipient APCs is responsible for maintaining T cells with indirect allospecificity in vivo and that, in the context of partial DR matching, indirect presentation by the parenchymal cells of the graft may serve to induce tolerance in T cells with indirect allospecificity.
Influence of acute rejection episodes, HLA matching, and donor/recipient phenotype on the development of 'early' transplant-associated coronary artery disease.
BACKGROUND: Transplant-associated coronary artery disease (TxCAD) is the manifestation of chronic rejection in the cardiac allograft. Both immunological and nonimmunological factors contribute to its development. Stratification by the time of development of TxCAD has not been considered previously for an extensive transplant series and may provide a means for apportioning relative risk factors appropriately. Specifically, TxCAD that develops early may have a pathogenesis different from TxCAD that develops later; ie, immunological factors play a more significant role in early development of TxCAD compared with later forms of the disease or in recipients where it has not been found. METHODS AND RESULTS: Between 1980 and 1994, 550 heart transplant recipients with postmortem data or yearly angiograms, donor:recipient serological HLA typing, and biopsy data were reviewed. Recipients were divided into four groups: Very Early (<1 year), Early (1-2 years), Late (3-14 years), and None (clear angio >3 years). There was a significant association between the number of histologically proven acute rejection episodes within 3 months and at 1 year and the development of early TxCAD. The number of acute rejection episodes within 3 months and 1 year is also significantly related to freedom of development of TxCAD. There was no significant association between the mean number of mismatches for Class I or Class II antigens, nor could any Class I/II phenotype for recipient or donor be identified that exerted a protective or deleterious effect. A lack of any association or trend with HLA data is demonstrated. CONCLUSIONS: These differences in pathogenesis between early and late TxCAD help define the importance of acute rejection in the etiology of chronic cardiac rejection. Stratification by time of development of TxCAD may provide further insight into defining the relative importance of other risk factors associated with the development of TxCAD. The lack of association with HLA data is discussed.
Pulsatile and nonpulsatile perfusion: the continuing controversy.
This report discusses pulsatile and nonpulsatile perfusion with regard to hemodynamics, cell metabolism, and the visceral consequences of these forms of cardiopulmonary bypass. It argues that differences between the two modes and a benefit for pulsatile perfusion, are most clearly manifested in identifiable high-risk patient groups.
Direct and indirect pathways of alloantigen recognition: relevance to acute and chronic allograft rejection.
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Rational approach to combined carotid and ischaemic heart disease.
BACKGROUND: The management of patients with concomitant coronary and carotid artery disease remains a controversial subject. The aim of this review was to develop a rational plan for the management of such patients based on a review of the literature. METHOD AND RESULTS: A retrospective review was carried out of relevant papers derived from the Medline database from 1964 to 1996. CONCLUSION: The management of patients with concomitant coronary and carotid artery disease has not yet been put to the test in a properly designed and randomized multicentre trial. It is suggested that, until the results of such a trial are available, the rational approach to combined symptomatic disease is combined carotid endarterectomy and coronary artery bypass grafting (CABG). Combined surgery is also appropriate for patients with symptomatic carotid artery disease and significant but asymptomatic cardiac disease. At present there is inadequate evidence to promote carotid endarterectomy for asymptomatic disease in combination with CABG.
Should business management training be part of medical education?
The introduction of modern business management practices in the National Health Service has exposed different levels of management training and expertise between clinicians and hospital managers. This is undesirable and frequently unproductive. This article puts the case for the inclusion of business management training within undergraduate and postgraduate curricula.
Blood contact activation: pathophysiological effects and therapeutic approaches.
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Cardiopulmonary bypass and the adaptive immune system: perspectives on T cell function.
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Videothoracoscopy in the treatment of early empyema: an initial experience.
Seventeen consecutive patients were referred for management of empyema between April 1991 and March 1992. Fourteen patients defined as having an 'early' empyema were initially treated by videothoracoscopy. The other three patients, defined as having a 'late' empyema proceeded directly to thoracotomy. Videothoracoscopy was successful in 10 out of the 14 patients. The mean postoperative stay was 7.8 days. At a mean follow-up at 16.7 months, these patients were rendered apyrexial with full lung expansion and no residual pleural collection. The postoperative results were at least equivalent to other conventional forms of treatment without an undue level of complications. In this series, thoracoscopy was found to be successful when symptoms had been present up to 31 days before presentation at the first hospital, and the mean length of treatment before referral to Harefield was 47 days. It is now our policy to videothoracoscope all patients with empyema thoracis, regardless of the length of referral. It may circumvent the need for a thoracotomy, it does not add any increased risk of complications, and does not appreciably increase the length of hospital stay should thoracotomy ultimately be required.
Severe hyponatraemia in elderly patients: cause for concern.
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Tricuspid valve replacement subsequent to previous open heart surgery.
BACKGROUND AND AIMS OF THE STUDY: Earlier surgical intervention to the mitral and/or aortic valve means that it will be uncommon to replace the tricuspid valve (TVR) in a patient who has not had prior open heart surgery. METHODS: We report the short and medium term results of a consecutive series of 14 patients who underwent bioprosthetic TVR between December 1985 and February 1993 at the Hammersmith Hospital, UK. All patients had undergone previous open heart surgery on at least one occasion. Mean patient age was 59 years (range: 45-77 years), 11 were female and three were male. Ten patients (72%) were in New York Heart Association class III or IV preoperatively, eight patients were first time reoperations and six patients were second time reoperations. RESULTS: Hospital mortality was 50% (7/14). Of these seven patients, six were in NYHA class III or IV preoperatively, and three were second time reoperations. There were no 'on-the-table deaths' and no patients required reoperation for bleeding or permanent pacing. For the patients discharged from hospital, the mean follow up was 46 months (range 9-84 months) and it was 100% complete. There was no significant difference in the preoperative assessment data between the hospital mortality group and the patients who left hospital (p > 0.05). Of the patients discharged, four (57% of this group, 28.5% of all patients) showed an improvement in NYHA classification and all patients reported a reduction in peripheral edema. Amongst the survivors there was 100% freedom from valve related complications. Within this group there have been three deaths since discharge, all due to biventricular failure. CONCLUSIONS: From this study we conclude that TVR in patients who have had prior cardiac surgery is a high risk procedure. Nonetheless, amongst survivors, benefit may be gained by either a reduction in peripheral edema and/or an improvement in NYHA class.
How should a patient presenting with unstable angina and a recent stroke be managed?
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Nocardia asteroides purulent pericarditis.
A case is reported of a 71-year-old woman who developed cardiac tamponade as a result of a pyopericardium. The causative organism was Nocardia asteroides. This is the first reported case in the United Kingdom and only the 9th to be reported in the world. Despite prior radiological and echocardiographic investigations, we were unprepared at surgery for the volume of pus encountered. The dense adhesions, adherent pericardium and loculations encountered emphasizes the need to explore such patients surgically. We would advocate vigilance as to the possibility of pericardial involvement, in any patient contracting Nocardia asteroides infection. The medical and surgical management of this case is discussed together with a review of the literature.
High frequency of alloreactive T cells is a consequence of the presentation of many peptides by allogeneic MHC molecules.
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Is aprotinin safe when used in the context of profound hypothermia and circulatory arrest? A literary review.
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Cerebral complications after coronary bypass grafting.
As the mortality associated with coronary artery bypass grafting has fallen, morbidity has become an increasing concern both by the medical profession and the general public. Postoperative quality of life, including the socioeconomic concern of returning to gainful employment, is of supreme importance. It is in this regard that brain injury following coronary artery bypass grafting is devastating if it leaves the patient with persistent motor, sensory, behavioral, or intellectual deficiencies. This paper reviews the cerebral complications following surgery for coronary artery disease. The extent of the problem is defined, and pathological mechanisms of injury together with methods employed to investigate cerebral pathology and physiology are reviewed. Finally, interventions which have been and are currently employed in an attempt to reduce cerebral injury are discussed.