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Biomedical subjects

W H Bain

Publications and source records attributed to W H Bain.

At least 37 records · Page 2Linked to original sources
PubMed1986

Cardiac surgery in patients with functional renal transplants.

The results of cardiac surgery in 7 patients with functioning renal transplants are reported. In all cases surgery was carried out using standard operative techniques whilst renal perfusion was enhanced where necessary by the use of a dopamine infusion. The immediate postoperative course was uneventful in all cases, though 2 out of 4 patients with ischemic heart disease have since experienced recurrent symptoms. Cardiac surgery may be performed in patients with functioning renal transplants with acceptable mortality and morbidity.

Adult↗
PubMed1986

Fourteen years' experience with the Björk-Shiley tilting disc prosthesis.

Between 1970 and 1984, 1,574 Björk-Shiley valve prostheses have been implanted in 1,171 patients in Glasgow. Between 1970 and 1980, 1,023 standard disc prostheses were implanted in 729 patients: 184 had aortic valve replacement, 323 mitral, and 222 multiple valve replacement. Between 1980 and 1984, 551 convexo-concave valves were implanted in 442 patients: 125 had aortic, 228 mitral, and 89 multiple valve replacement. Concomitant coronary artery bypass grafting was performed in 9.2% of the latter group as compared with 2.7% of the earlier group. The overall hospital (30 day) mortality for the group with the standard disc prosthesis was 10.4% and for patients with the convexo-concave prosthesis, 7.0%. Cumulative follow-up extends to 4,125 patient-years--standard disc group 3,378 patients-years, range 4 to 14 years (mean 5.2 years); convexo-concave group 747 patient-years, range 1.5 to 5.3 years (mean 1.9 years). The late mortality is 3.8% per patient-year--standard disc group 2.9% per patient-year and convexo-concave group 4.3% per patient year (no significant difference). Actuarial survival rate at 12 years for the whole group, excluding operative deaths, is 69.4% +/- 6.3%. The freedom from all valve-related complications at 12 years is 65.9% +/- 6.5%. there is no significant difference in the incidence of most major complications between the standard disc and convexo-concave prostheses apart from the occurrence of mitral valve thrombosis (p less than 0.05) in the standard disc group and outlet strut fracture (p less than 0.005) in the convexo-concave group. These results confirm the excellent long-term performance of the Björk-Shiley tilting disc prosthesis.

Actuarial Analysis↗
PubMed1985

Computerized system for the follow-up of patients with heart valve replacements.

A system is described which will accept, store, retrieve and analyze information on large numbers of patients who undergo valve replacement surgery. The purpose of the database is to yield readily available facts concerning the patient's clinical course, prosthetic valve function, length of survival, and incidence of complications. The system uses the Apple Macintosh computer, which is one of the current examples of small, desk-top microprocessors. The software for the input, editing and analysis programs has been written by a professional software writer in close collaboration with a cardiac surgeon. Its content is based on 8 years' experience of computer-based valve follow-up. The system is inexpensive and has proved easy to use in practice.

Computers↗
PubMed1985

Pericardectomy.

Explore the source record for details and available documents.

Adolescent↗
PubMed1984

Rupture of posterior wall of left ventricle after mitral valve replacement.

Possible aetiological factors, presentation, and management were reviewed in 18 patients with posterior left ventricular rupture complicating mitral valve replacement seen at one centre over six and a half years. The patients were elderly (mean age 57), predominantly women (16 of the 18), and suffering from mitral stenosis. Rupture was much more common after isolated replacement of the mitral valve (16 out of 797 operations) than after double valve replacement (one out 236) or mitral valve replacement and coronary artery bypass graft (one out of 70). A total of 1221 mitral valve replacements were performed over this period, with an overall incidence of rupture of 1.47%. Damage to the valve annulus occurred five times. On four occasions haemorrhage followed a vigorous response to a bolus dose of an inotrope. With the exception of these features, it was difficult to define specific risk factors. Eleven patients bled while still in theatre; one of them survived long term and another four lived for four to 10 days. Repair after restarting cardiopulmonary bypass made short term survival much more likely. In seven rupture developed after return to the intensive therapy unit; again only one survived long term. In nearly all cases bleeding was at, or just below, the atrioventricular groove. Rupture probably occurs after endocardial damage to a thin myocardium that has lost the internal buttress of the subvalvar apparatus. With the rise in intraventricular pressure at the end of bypass blood dissects into the myocardium, resulting in a large haematoma and eventual rupture.

Adult↗
PubMed1984

Thrombotic obstruction of the Björk-Shiley valve: the Glasgow experience.

Thrombotic obstruction is the most feared complication of the Björk-Shiley tilting disc prosthesis. From 1971 to 1982 1186 Björk-Shiley valves were implanted in 900 patients. There were 93 deaths in hospital. Eight hundred and seven patients have been followed for a total of 4146 patient years; 14 patients were lost to follow up. Nineteen cases of thrombotic obstruction were identified at necropsy or at a repeat operation in the study group. The mitral prosthesis was thrombosed in 16 patients, the aortic in two, and the tricuspid in one. The incidence for this complication has been calculated to be 0.46 per 100 patient years for all valve positions, 0.79 for single mitral valve replacements, 0.18 for aortic replacements, and 0.63/100 for the tricuspid position. The maximum possible incidence of this complication in this population has been calculated to be 1.4 per 100 patient years. The mortality rate was 41.7% for reoperation and 63% for the development of the complication. Risk factors that have been identified are inadequate anticoagulant control, poor preoperative exercise capacity, and possibly also the implantation of small prostheses.

Aortic Valve↗
PubMed1982

Comparative clinical study of pulsatile and non-pulsatile perfusion in 350 consecutive patients.

Pulsatile perfusion has been shown to offer significant haemodynamic advantages over non-pulsatile perfusion in many experimental studies. Clinical acceptance of pulsatile perfusion during cardiac surgical procedures has, however, been hampered by the lack of technologically satisfactory pulsatile pump systems, and by inadequate clinical experience of routine use of pulsatile perfusion. The recent introduction of reliable pulsatile pump systems with low haemolysis characteristics has made possible the clinical validation of the previous experimental studies. We describe the results of a prospective study of mortality, haemodynamic morbidity, and haematological status, in 350 consecutive adult patients submitted to cardiopulmonary bypass procedures in a surgical unit over a 12-month period. One hundred and seventy five patients were perfused with conventional non-pulsatile flow and 175 with pulsatile flow, using a modified roller-pump pulsatile system (Cobe-Stockert). The groups were closely similar in terms of preoperative characteristics, referral category, and pathology requiring surgery. Operative techniques, bypass parameters, and anaesthetic regime were standardised in both groups. The results were as follows. (1) Total mortality was significantly lower in the pulsatile group (4.6%) compared with the non-pulsatile group (10.3%), p = 0.06. (2) The incidence of deaths attributable to post-perfusion low cardiac output was significantly lower in the pulsatile group (1.1% compared with 6.3%, p = 0.02). (3) Requirement for mechanical (intra-aortic balloon) or drug circulatory support was significantly lower in the pulsatile group. (4) The use of pulsatile perfusion was not associated with any increase in haemolysis, blood cell depletion, or postoperative bleeding problems.

Adult↗
PubMed1982

Psychological factors and recovery from cardiac surgery.

21 Subjects awaiting open-heart surgery were given personality and attitude questionnaires. They were re-tested six months after the operation, when they were divided into "completely recovered" (I) and "not completely recovered" (II) groups, according to the New York Heart Association classification. Results showed that Group I was significantly less depressed, more optimistic about the future and had a more positive attitude towards others. Group II realised they had been very ill and had a more negative attitude towards their spouses. Group I was found to be much better adjusted, vocationally and psychosexually, than Group II.

Adaptation, Psychological↗
PubMed1979

Role of angiotensin II in the development of peripheral vasoconstriction during cardiopulmonary bypass.

The possible relationship between angiotensin II -- the end product of the renin-angiotensin system, and the increase in peripheral vasoconstriction associated with cardiopulmonary bypass, has been investigated in 12 patients undergoing elective open-heart surgical procedures. Plasma angiotensin II (AII) levels were measured by radio-immunoassay at the start and the end of the period of cardiopulmonary bypass. Measurements of peripheral vascular resistance index were made at the times of AII sampling. Plasma AII levels rose during CPB from 78.0 to 231.3 pg.cm-3 (normal values less than 35 pg.cm-3). Peripheral vascular resistance index also rose during perfusion from 20.87 to 27.83 units. The rise in plasma AII levels and in peripheral vascular resistance index were correlated for each of the 12 patients. A highly significant correlation was obtained (r = 0.91; P less than 0.001). These results confirm the presence of parallel rises in plasma angiotensin II levels and in peripheral vasoconstriction during conventional non-pulsatile cardiopulmonary bypass, and suggest that increased plasma AII levels may be principal causative factor in the increased vasoconstriction associated with open-heart surgical procedures.

Adult↗
PubMed1979

Peripheral vascular resistance and angiotensin II levels during pulsatile and non-pulsatile cardiopulmonary bypass.

The effects of pulsatile and non-pulsatile cardiopulmonary bypass (CPB) on levels of peripheral vascular resistance and plasma angiotensin II (AII) have been studied in 24 patients submitted to elective cardiac surgical procedures. Twelve patients had conventional non-pulsatile perfusion throughout the period of CPB (non-pulsatile group), while 12 had pulsatile perfusion during the central period of total CPB, using the Stockert pulsatile pump system (pulsatile group). There were no significant differences between the groups in respect of age, weight, bypass time, cross-clamp time, or in mean pump flow or mean perfusion pressure at the onset of CPB. Peripheral vascular resistance index (PVRI) and plasma AII levels were measured at the onset of total CPB and at the end of total CPB. In the non-pulsatile group PVRI rose from 19.6 units to 29.96 units during perfusion. In the pulsatile group PVRI showed little change from 20.89 units to 21.45 units during perfusion (P less than 0.001). Plasma AII levels (normal less than 35 pg/ml) rose during perfusion from 49 pg/ml to 226 pg/ml in the non-pulsatile group. The rise in the pulsatile group from 44 pg/ml to 98 pg/ml was significantly smaller than that in the non-pulsatile group (P less than 0.01). These results indicate that pulsatile cardiopulmonary bypass prevents the rise in PVRI associated with non-pulsatile perfusion, and that this effect may be achieved by preventing excessive activation of the renin-angiotensin system, thus producing significantly lower plasma concentrations of the vasoconstrictor angiotensin II.

Adult↗
PubMed1979

Failure of pacemaker electrode leads.

With the application of new power sources to pacemakers, considerable improvement has been achieved in the theoretical implant lifetime of current pulse generators, and equally reliable electrode leads will be necessary to ensure long-term pacing. The durability of the electrodes implanted in the past ten years in this centre has been carefully studied. The findings suggest that the use of a more durable conductor material and development of the concept of a 'fail safe' lead (using multi-filament conductors or a secondary conductive pathway along the electrode) will be necessary to match with the implant lifetime of the newer pulse generators. The diagnosis and management of broken conductors is discussed.

Electrodes, Implanted↗
PubMed1978

Repeated failure of nickel-containing prosthetic heart valves in a patient allergic to nickel.

Life-threatening peri-prosthetic incompetence developed with two successive nickel-containing mitral-valve prostheses in a patient allergic to nickel. Neither prosthesis had been incorporated satisfactorily. Her present nickel-free prosthesis seems to be satisfactory 22 months after insertion. Since allergy to nickel may have been involved in the failure of these prostheses, it is recommended that nickel-sensitive patients should be given nickel-free prostheses.

Female↗
PubMed1978

Anterior pituitary response to thyrotrophin-releasing hormone during open-heart surgery.

The anterior pituitary response to thyrotrophin-releasing hormone has been studied in 20 patients submitted to elective open-heart surgical procedures, and in six control patients submitted to closed mitral valvotomy. Standard non-pulsatile normothermic perfusion was used in all the open-heart cases. 400 microgram thyrotropin-releasing hormone was administered by intravenous injection during bypass, at 30 min post-bypass, and at 60 min post-bypass. The same dose (400 microgram) was given during closed mitral valvotomy (Control Group). Thyrotrophin-releasing hormone administration during bypass failed to produce a normal response from the anterior pituitary, in contrast to the normal response pattern seen in the control group (P less than 0.01). Thyrotrophin-releasing hormone given after the period of bypass produced responses within the normal range in the majority of patients. These results suggest that anterior pituitary hypofunction may exist during the period of extracorporeal circulation using non-pulsatile perfusion and that recovery of pituitary function is evident within the first hour post-extracorporeal circulation.

Cardiac Surgical Procedures↗
PubMed1978

Hypothalamo-pituitary-thyroid axis function during cardiopulmonary bypass.

Marked alterations in levels of circulating thyroid hormone were found in patients undergoing cardiopulmonary bypass with a rise in the free thyroxine and a fall in the free triiodothyronine levels. Studies using thyrotropin-releasing hormone during bypass demonstrated a blunted response to this stimulus. This reduced response is related to changes in thyroid hormone levels and it is suggested that bypass surgery may have a direct inhibitory action on thyroid-stimulating hormone release at the hypothalamo-pituitary level. The potential significance of these hormonal changes is discussed.

Adult↗