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Biomedical subjects

T A English

Publications and source records attributed to T A English.

At least 55 records · Page 3Linked to original sources
PubMed1985

Haemodialysis and haemofiltration on cardiopulmonary bypass.

Over a three year period we have used haemodialysis and haemofiltration in parallel with cardiopulmonary bypass in 26 patients. Impaired renal function and excessive fluid retention have been the main indications. Patients on haemodialysis programmes for end stage renal failure did not require further dialysis until at least the third postoperative day, when they could tolerate the haemodynamic disturbance of dialysis. In the other patients these techniques proved valuable in reversing the effects of haemodilution and in controlling the concentration of serum potassium. Our experience has confirmed that haemodialysis and haemofiltration in parallel with cardiopulmonary bypass are useful adjuncts in the perioperative management of patients with impaired renal function undergoing open heart surgery. The techniques are also effective in correcting the fluid retention and biochemical imbalance in patients with congestive cardiac failure, including those with heart transplants.

Adolescent↗
PubMed1985

Incidence and aetiology of a raised hemidiaphragm after cardiopulmonary bypass.

A raised hemidiaphragm has been reported as an uncommon complication of cardiopulmonary bypass, possibly resulting from cold injury to the phrenic nerve. At Papworth Hospital myocardial protection during cardiac arrest relies in part on irrigation of the pericardial cavity with large volumes of Hartmann's solution at 4 degrees C. Retrospective review of the chest radiographs of 100 consecutive patients undergoing cardiopulmonary bypass showed that 31 had a raised left hemidiaphragm soon after operation. The only significant correlation was with aortic cross clamp time (p less than 0.03). A prospective study of 36 consecutive patients undergoing cardiopulmonary bypass was then undertaken with diaphragmatic screening and chest radiography. Preoperative screening gave normal results in all patients. In the early postoperative period 16 (44%) had left diaphragmatic weakness or paralysis, two (5.5%) right sided weakness, and two (5.5%) bilateral weakness. Repeat screening of these patients showed resolution in all but four cases (80%) at six months and in all but two (90%) at one year. The greater number of left sided lesions than of right (8:1) is probably due to the fact that the cold jet of irrigating fluid is directed towards the left phrenic nerve. These findings have implications with regard to the optimum temperature of the irrigant fluid for myocardial protection during cardiopulmonary bypass.

Adolescent↗
PubMed1985

Cytomegalovirus infection in cardiac transplant recipients associated with chronic T cell subset ratio inversion with expansion of a Leu-7+ TS-C+ subset.

Lymphocyte subsets were analysed in 18 patients during the first 3 years after cardiac transplantation. The patients received Cyclosporin A and prednisolone for maintenance immunosuppression. Serological evidence of active cytomegalovirus (CMV) infection was found in 13 cases (72%), and in 12 of these an inversion usually of the T helper/T suppressor-cytotoxic ratio (TH/TS-C) was detected. T subset inversion usually preceded the diagnostic rise in CMV antibody titre. In 69% of patients with CMV the TH/TS-C ratio remained inverted throughout follow-up (245-951 days). Persistent T subset inversion was not found in all five patients who lacked serological evidence of active CMV. Chronic inversion consisted of an average increase in TS-C of 152% and an average decline in TH cells of 31% as compared to CMV negative patients. The proportion of lymphoid cells reacting with a phenotypic marker for natural killer (NK) cells (Leu-7) was increased by 83%. These alterations were also reflected in the absolute numbers of cells with these markers. Two-colour immunofluorescence analysis revealed that the expanded TS-C population present during chronic inversion was predominantly Leu-7+. As TS-C+ Leu-7+ cells in healthy persons may be hyporesponsive NK cells, a sustained increase in this cell type in allograft recipients could further reduce immunocompetence, thereby predisposing to superinfection or malignancy.

Adult↗
PubMed1985

Significance of donor transmitted disease in cardiac transplantation.

Infectious complications constitute a major cause of morbidity and mortality after heart transplantation. Those infections transmitted with the transplanted heart are potentially avoidable. Cytomegalovirus infections and toxoplasmosis occupy a prominent position in this category. The outcome of transplanting hearts from donors previously exposed to these infections depends largely on the existing immune status of the recipient. This paper is a retrospective study on the incidence of Toxoplasma gondii and cytomegalovirus infections in patients undergoing heart and heart-lung transplantation at Papworth Hospital, Cambridge.

Adolescent↗
PubMed1985

Is cyclosporine's nephrotoxicity related to its immunosuppressive effectiveness?

A fatal early acute rejection occurred in a heart allograft recipient immunosuppressed with Cyclosporine. This failure to prevent rejection in spite of satisfactory plasma levels of Cyclosporine was associated with total absence of renal impairment. The latter has always been present in our experience. The absence of immune and nephrotoxic effects raises the question of a biological defect in this patient, possibly a lack of specific receptors for Cyclosporine.

Cyclosporins↗
PubMed1984

The UK cardiac surgical register, 1977-82.

Data for 1977-82 obtained from the Cardiac Surgical Register, established by the Society of Thoracic and Cardiovascular Surgeons of Great Britain and Northern Ireland in 1977, were analysed for trends in incidence and mortality of cardiac surgery and regional workload in the United Kingdom. Operative mortality for most types of cardiac operation showed a general decline. The numbers of operations performed for valvular and congenital heart disease had remained unchanged, but a striking increase had occurred in the number of coronary bypass graft operations: 2297 in 1977 to 6008 in 1982. The figure for 1982, representing an annual rate of 107 operations per million population, was still well below that for other countries such as Australia (410 per million in 1982) and the United States (750 per million in 1981). A wide variation was seen in the regional provision of cardiac surgical services within the United Kingdom. This was particularly appreciable for coronary bypass graft surgery, in which there was a 10-fold difference in numbers of operations performed between the various regions. The UK Cardiac Surgical Register provides an important source of information on trends within the specialty that could well be followed by other surgical specialties.

Adult↗
PubMed1984

Selection and procurement of hearts for transplantation.

The success of orthotopic heart transplantation depends wholly on satisfactory function of the new heart on completion of the operation. This in turn depends on the quality of the donor heart before its removal, the effectiveness of the methods used to preserve it during transport from the donor to the recipient hospital, and the accuracy of the operative procedure. From January 1979 to December 1983, 62 donor hearts were transplanted into 61 recipients at Papworth Hospital. These hearts were selected from 250 offered for consideration. The most common reasons for not proceeding with an initial inquiry were failure of the donor to meet the medical criteria for selection (77 cases) and lack of intensive care facilities or staff shortages such that a transplant could not be accommodated at the time of inquiry (80). Eight early deaths occurred, of which three were due to primary failure of the donor heart. Actual one and three year survivals for the whole programme were 58% and 50% respectively, the current actual one year survival being 70%. Forty per cent of patients selected for transplantation died while waiting for a heart to become available. Their average survival time was 46 days. The number of donor hearts referred for transplantation depends on public attitudes towards organ transplantation, the willingness of doctors looking after brain dead patients to seek permission from relatives for the heart to be donated, and the cooperation of local kidney transplant surgeons. A larger number of suitable donor hearts to choose from would enable more patients to be treated, as transplant operations could be arranged so that existing facilities were used to their maximum capacity.

Adolescent↗
PubMed1984

The electrophysiologic characteristics of the transplanted human heart.

The electrophysiologic characteristics of the denervated human heart were assessed in 14 cardiac transplant recipients. Conduction intervals and refractory periods were measured at pacing cycle lengths of 500 msec and 400 msec. The faster pacing rate caused lengthening of the AH interval (83 +/- 23 msec to 116 +/- 41 msec, p less than 0.01) and shortening of the QT (338 +/- 27 msec to 313 +/- 22 msec, p less than 0.001) and JT (249 +/- 21 msec to 229 +/- 19 msec, p less than 0.001) intervals. There was no change in the SA, HV, or QRS durations. Wenckebach periodicity occurred at a longer cycle length in the retrograde than in the anterograde direction (409 +/- 96 msec vs 318 +/- 46 msec, p less than 0.01) and anterograde conduction was better than retrograde conduction in 13 of the 14 patients (93%). Increasing pacing cycle length resulted in shortening of the atrial effective (203 +/- 28 msec to 190 +/- 25 msec, p less than 0.001), ventricular effective (224 +/- 18 msec to 211 +/- 17 msec, p less than 0.01), and AV nodal functional (367 +/- 38 msec to 357 +/- 36 msec, NS) refractory periods. The AV nodal effective refractory period lengthened (294 +/- 31 msec to 314 +/- 52 msec, p less than 0.05). There was a close correlation between AV Wenckebach cycle length and the functional refractory period of the AV node (r = 0.853, p less than 0.001). These results are qualitatively and quantitatively similar to those reported in the innervated heart. The autonomic nervous system appears to have little influence on the resting electrophysiologic characteristics of the atrioventricular conduction system in the innervated heart.

Adult↗
PubMed1984

Sinoatrial function after cardiac transplantation.

The function of both the denervated donor and innervated recipient sinus nodes of 14 asymptomatic cardiac transplant recipients was assessed. Tests of sinoatrial function were performed in 14 donor and 10 recipient atria. The mean spontaneous cycle length of the recipient atria was significantly longer than that of the donor atria (944 +/- 246 versus 663 +/- 158 ms, p less than 0.01). Donor sinus node recovery time was prolonged in four patients (greater than 2,500 ms in two) and recipient recovery time was prolonged in six patients. In those patients with normal sinus node function tests, the recovery time of the recipient sinus node was longer than that of the donor sinus node (1,170 +/- 207 versus 864 +/- 175 ms, p less than 0.02). The pattern of response of recovery times to increasing pacing rate was predictable and organized in the donor but chaotic in the recipient, and the longest sinus node recovery time occurred at the shortest pacing cycle length used in 12 of the 14 donor atria but in only 1 of the 10 recipient atria (p less than 0.001). Secondary pauses occurred in none of the normal donor atria and in all of the abnormal donor atria (p less than 0.001); however, they occurred in both normal and abnormal recipient atria. The recipient and donor atria were paced alone and synchronously in the same patients. Synchronous pacing had no effect on the recovery times of the donor sinus node but significantly lengthened those of the recipient (sinus node recovery time: 1,266 +/- 218 to 1,547 +/- 332 ms, p less than 0.02; corrected recovery time: 322 +/- 102 to 686 +/- 188 ms, p less than 0.01). In the donor atria, abnormal recovery time was invariably associated with abnormal sinoatrial conduction time. There was a strong correlation between sinoatrial conduction time measured by the methods of Strauss and Narula and their coworkers in the donor atria (r = 0.98, p less than 0.001) but not in the recipient atria (r = 0.72). In the absence of autonomic influences, tests of sinus node function of the donor atria produce predictable and consistent results and, therefore, may be more clinically reliable than in intact human subjects. There is a high incidence of recipient sinus node dysfunction in asymptomatic long-term survivors of cardiac transplantation.

Adult↗
PubMed1984

Metabolic changes in the autotransplanted baboon heart.

Chronic denervation of the heart leads to depletion of tissue catecholamines, giving rise to metabolic abnormalities, including a reduction in cardiac glucose oxidation. Impaired glucose oxidation could cause an increased oxidation of fat, which in turn could lead to development of coronary artery disease. Cardiac glucose oxidation (using 14C-(U),D-glucose) was studied in female baboons, before, and three to five weeks after, autotransplantation. Systemic arterial and coronary sinus samples were analyzed for total CO2 content, O2 content, 14CO2, glucose, lactate, pH, PCO2, and PO2. Tissue for metabolite assays (adenosine-5'-triphosphate [ADP] and creatine phosphate [CP]; glucose-6-phosphate [G6P] and fructose 6-phosphate [F6P] was obtained from the right ventricle before and after autotransplantation in some animals. There were no significant changes. Tissue was also obtained postmortem for analysis of noradrenaline, soluble tyrosine hydroxylase activity, and contractile and regulatory proteins. There was a large decrease in tissue noradrenaline, suggesting almost total sympathetic denervation. The level of tyrosine hydroxylase activity shows that the denervated heart can synthesize dopamine. There were no detectable changes in the contractile or regulatory proteins. In six of the nine baboons successfully studied, there was a distinct decrease in the oxidation of glucose after autotransplantation (P less than 0.05). This indicates that the removal of the sympathetic and parasympathetic nerve supply to the heart affects the ratio of glucose oxidized to other substrates.

Adenosine Triphosphate↗
PubMed1984

Disseminated toxoplasmosis in cardiac transplantation.

The first case of disseminated toxoplasmosis following cardiac transplantation in the UK is described, with details of Toxoplasma antibody tests made on other cardiac transplant patients. Sixteen of 40 (39%) of recipients had Toxoplasma antibody before operation. Eleven of 30 (37%) of donors had Toxoplasma antibody. The were four occasions when a negative recipient received a heart from a positive donor. Three survived the immediate postoperative period and two became infected with toxoplasmosis. The implications of this are discussed. Disseminated toxoplasmosis appears much more often when heart muscle from a dye test positive donor is given to a dye test negative recipient. Antibiotic therapy is limited by the fact that the antitoxoplasma drugs available are static in their effect, and need to be given for prolonged periods postoperatively.

Adult↗
PubMed1984

Anti-heart antibodies in cardiac allograft recipients.

Serum antibodies reactive with rat cardiac and skeletal muscle were found by indirect immunofluorescence in 11 of 16 heart transplant patients receiving heterologous antithymocyte globulin and 1 of 5 patients receiving cyclosporin A. These antibodies appeared de novo following transplantation and were present for variable lengths of time. Antibodies reactive with rat liver, stomach and kidney were also found in several patients, 9 out of 16 patients receiving equine globulin had antibodies directed against components of the microvasculature, including endothelial, smooth muscle and vessel wall connective tissue. Analysis of antibody kinetics and acute cardiac rejection did not reveal any well-defined associations, though anti-heart antibodies were present in 4 of 6 patients who died from acute rejection.

Acute Disease↗
PubMed1983

Serial analysis of circulating immune complexes, complement, and antithymocyte globulin antibodies in heart transplant recipients.

Thirteen heart transplant patients receiving heterologous antithymocyte globulin were examined serially for the presence of circulating immune complexes, activation of complement, and antibodies to antithymocyte globulin. Using three independent assays, all patients were found to develop immune complexes at some time following transplantation, mostly as a consequence of antithymocyte globulin administration and infection. Simultaneous analysis of endogenous complement levels revealed C3 and C4 hypocomplementaemia in 28 and 44% of the samples, respectively. However, no correlation was evident between immune complex or complement levels and cardiac rejection assessed histologically in 64 endomyocardial biopsies. Serial analysis of antibodies to equine and rabbit antithymocyte globulin by solid-phase radioimmunoassay showed that 8 of 10 patients had significantly elevated values. Evidence was also obtained which indicated a substantial degree of cross-reactivity between the antibodies to these heterologous proteins. The results demonstrate a complex interplay of immune reactants relating to transplantation, infection, and immunosuppression therapy.

Adult↗
PubMed1983

Unusual atrial potentials in a cardiac transplant recipient. Possible synchronization between donor and recipient atria.

It is usual to record independent activity from both the innervated recipient and the denervated donor atria in cardiac transplant recipients except for occasional, short-lived periods of entrainment that may occur during exercise. In this report a case is described in which, following orthotopic cardiac transplantation, the recipient and donor atria remained synchronized during a variety of physiological and non-physiological situations. Under no circumstances did the two sets of atria beat independently. The mechanisms that might be involved in this unique situation are discussed.

Adult↗
PubMed1983

Effect of beta blockade on exercise response after cardiac transplantation.

Six cardiac transplant recipients underwent maximal exercise testing before and after the administration of intravenous propranolol to assess the effect of beta blockade on their exercise heart rate response and exercise capacity. Before propranolol the patients were capable of a mean of 6.8 minutes of exercise and heart rate increased from a resting value of 102 +/- 25 a minute to 138 +/- 34 at peak exercise--a mean increase of 35%. All tests were terminated because of tiredness or muscle weakness. After one hour's rest, intravenous propranolol (0.2 mg/kg over 10 minutes) was administered with a reduction in resting heart rate from 109 +/- 28 a minute to 83 +/- 16. During the repeat exercise test the patients were capable of a mean of 4.5 minutes of exercise and all tests were terminated by extreme exhaustion and/or unsteadiness requiring immediate cessation of the treadmill. Heart rate increased from a resting value of 83 +/- 16 a minute to 96 +/- 18 at peak exercise. The exercise capability of the denervated heart is conspicuously reduced by beta blockade, presumably because of its reliance on circulating catecholamines.

Adult↗
PubMed1983

Effects of coronary artery bypass grafting on left ventricular function assessed by multiple gated ventricular scintigraphy.

The effect of coronary artery bypass grafting on global left ventricular ejection fraction and regional contraction was studied in 56 consecutive patients with chronic stable angina pectoris by means of multiple gated ventricular scintigraphy at rest and during dynamic supine exercise before and six weeks after myocardial revascularisation. Before operation, exercise induced a significant fall in ejection fraction and regional wall motion score. Six weeks after operation 52 patients were symptomless. Resting ejection fraction and regional wall motion score were unchanged but during exercise ejection fraction increased significantly, and the previous exercise induced regional wall motion abnormalities were abolished. All four patients with persisting angina showed the same pattern as before operation, with a fall in left ventricular ejection fraction and regional wall motion score during exercise. Multiple gated ventricular scintigraphy affords a safe, objective, reproducible, and non-invasive means of assessing serial ventricular function at rest and during exercise in patients with ischaemic heart disease. The technique confirms that coronary bypass surgery abolishes exercise induced abnormalities of left ventricular function, but has no influence on resting function.

Angina Pectoris↗