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Biomedical subjects

A J Murday

Publications and source records attributed to A J Murday.

At least 37 records · Page 2Linked to original sources
PubMed1994

Creatine kinase MB isoforms: sensitive markers of ischemic myocardial damage.

We investigated the use of creatine kinase (CK) MB isoforms as a marker of myocardial cell injury in a preliminary study of 16 patients with chronic stable angina after successful percutaneous transluminal coronary angioplasty (PTCA) and 25 patients after coronary artery bypass grafting (CABG). Three control groups were studied: apparently healthy volunteers (n = 31), patients undergoing thoracotomy (n = 10), and patients undergoing routine coronary angiography (n = 9). Patients in the PTCA group showed an association between ischemic ST segment changes lasting > 3 min and a transient increase in the MB2/MB1 ratio; however, all had total CK-MB activity within normal limits. Routine coronary angiography subjects had no significant change in MB2/MB1. In the CABG patients, MB2/MB1 peaked within 1 h after the cross-clamp release and returned to baseline by 24 h postoperatively. The median time to peak MM3/MM1 and total CK-MB activity was 2 and 8 h after reperfusion, respectively, returning to baseline values by 2 and 5 days, respectively. After thoracotomy, MB2/MB1 was increased only in elderly patients (n = 5) with risk factors for ischemic heart disease; total CK-MB activity was increased in only three of these. Apparently, CK-MB isoforms can detect myocardial damage in clinical settings with less overt damage than myocardial infarction.

Adolescent↗
PubMed1992

Leiomyosarcoma of the pulmonary artery.

Successful resection of a pulmonary artery leiomyosarcoma was performed in a patient with clinical features of chronic pulmonary embolism. With radical radiotherapy to the mediastinum and solitary right hip metastasis, the patient remained well 6 months later. The difficulty of accurate diagnosis is considered in the light of recent advances in the techniques of cardiac investigation.

Female↗
PubMed1992

Problems associated with mechanical heart valve sounds.

A cross-sectional study of 50 randomly selected patients 12-36 months following mechanical heart valve replacement with Bjork-Shiley tilting disc valves was undertaken to investigate the factors which affect perception of, and reaction to, sounds generated by mechanical heart valves implanted in patients. Numerous problems were generated by the valves, including annoyance (68%), sleep disturbance (52% in patients; and 46% in patients' partners), interference with concentration (36%) and social embarrassment (28%). These findings are not affected by the measured level of sound or any variation in the number or anatomical position of the valve(s), though age and sex do seem to matter, more problems being reported by younger patients and those of the female sex. Aspects of the patient's personality did not seem to alter the difficulties experienced, though a high level of psychological morbidity was identified in the group as a whole. Most patients experience problems due directly to the noise generated by their valve and should be adequately warned of this before operation. This should also be taken into consideration in designing and evaluating new valve prostheses.

Adaptation, Psychological↗
PubMed1991

Long-term results of Ionescu-Shiley valve in the tricuspid position.

A retrospective analysis of the long-term results of using the Ionescu-Shiley pericardial bioprosthesis in the tricuspid position was carried out on 73 patients (8 men, 65 women). Of these procedures, ten were tricuspid valve replacement alone and the remainder were in combination with other valve procedures. The mean follow-up was 9.6 years (range, 4 to 18 years). The mean age of the patients was 53 years (range, 27 to 78 years). Seventy-one of the patients suffered tricuspid valve dysfunction from rheumatic heart disease. There were 13 postoperative deaths (within 30 days), giving a mortality rate of 17.8%. The actuarial survival at 10 years was 71% +/- 4.2%. Of the survivors, 49 (79.6%) were in functional class I or II. Primary tissue valve failure in the tricuspid position occurred in 1 patient 12 years after implantation and required reoperation. In another patient bioprosthetic tricuspid valve endocarditis developed. There was no incidence of thromboembolic complications. We conclude that the Ionescu-Shiley pericardial bioprosthesis was a satisfactory prosthesis in the tricuspid position in patients with acquired valvar dysfunction.

Adult↗
PubMed1990

Postoperative autologous transfusion in cardiac surgery. A prospective, randomised study.

To investigate the safety and efficacy of postoperative autologous blood transfusion (AT) using the Shiley hardshell venous reservoir, a prospective, randomised, controlled study was carried out in two matched groups of twenty patients undergoing elective coronary artery bypass surgery. The mean volume of shed mediastinal blood reinfused in the first 6 h postoperatively was 371.7 +/- 63.23 ml. Use of homologous blood was reduced from 760.5 +/- 108.37 ml in the control patients to 466.25 +/- 87.44 ml in the AT patients, a reduction of 38.7% (p less than 0.05). There was no statistically significant difference in the clinical outcome, overall blood loss, use of platelets, fresh frozen plasma and colloids, haematological indices, renal and hepatic functions, or clotting mechanism, although there was a reduction in the fibrinogen level in the patients who received AT (p less than 0.05). Mediastinal blood did not clot and was defibrinogenated. It contained significant levels of haemoglobin (8.175 +/- 0.506 g/dl), platelets (96.55 +/- 10.39 per mm3 10(3)), protein (42.5 +/- 1.13 g/l), calcium (2.385 +/- 0.054 mmol/l) and was well oxygenated (PO2 = 20.46 +/- 0.81 kPa). No patients developed bacteraemia or had any AT-related infections. We conclude that postoperative autologous transfusion using the Shiley hardshell venous reservoir is a safe and efficient method for reducing postoperative homologous blood requirement after coronary artery bypass surgery.

Adult↗
PubMed1989

Reoperation after pericardial closure with bovine pericardium.

To reduce the risk of damage to the anterior surface of the right ventricle after resternotomy, it has been recommended that the pericardium be closed with a patch after open heart operations. We have examined 4 patients undergoing resternotomy for the third time 3 to 8 years after bovine pericardium valve replacement. On each occasion the pericardium was closed with a patch of bovine pericardium. In all cases, the patch was frozen to the inner aspect of the sternum, increasing the difficulty of resternotomy. Histological examinations of the patches confirmed dense fibrous connective tissue, patchy calcification, and foreign body giant cell reaction. Bovine pericardium appears to increase the difficulty of repeat cardiac operations. We recommend its use be discontinued.

Adult↗
PubMed1987

Results of surgical repair for dissection of the ascending aorta.

Between 1970 and 1986, 40 patients had surgical treatment for dissection of the ascending aorta at the London Chest Hospital. The overall hospital mortality was 27.5%. Preoperative renal impairment and age greater than or equal to 60 years were both associated with a significantly increased hospital mortality. In the long term one patient was lost to follow up. There have been two late deaths among the remaining 28 patients (mean follow up 4.4 years). The functional state of the survivors is good, with only three having any cardiac disability.

Adolescent↗
PubMed1985

Adverse effects of high dose aspirin on platelet adhesion to experimental autogenous vein grafts.

Prostacyclin (PGI2) production and platelet adhesion were studied in veins grafted into the arterial system of rabbits. Animal groups consisted of: no treatment; low dose aspirin (ASA) (0.5 mg . kg-1 X 24 h-1) plus dipyridamole (2 mg . kg-1 X 6 h-1); high dose ASA (40 mg . kg-1 X 24 h-1) plus dipyridamole (2 mg . kg-1 X 6 h-1); dipyridamole (2 mg . kg-1 X 6 h-1) alone. Results showed that vein grafts from animals treated with high dose ASA plus dipyridamole produced significantly less PGI2 than the other three groups (p less than 0.05 compared with the dipyridamole group; p less than 0.01 compared with the other two groups). In addition, there was significantly greater platelet deposition on the vein grafts from this high dose ASA group as compared to the low dose ASA group (p less than 0.05). By contrast, animals treated with dipyridamole alone had significantly less platelet deposition compared to both the control and high dose ASA groups (p less than 0.05). High dose ASA given to prevent thrombotic occlusion following coronary artery bypass grafting may, by reducing PGI2, result in enhanced platelet deposition. This in turn is likely to increase intimal hyperplasia as has been demonstrated previously with high dose ASA. Clinical studies, which have shown the early anti-thrombotic benefits of high dose ASA plus dipyridamole, have not measured graft intimal thickness. Since this process is an important cause of graft narrowing, ASA, in high dose, may adversely affect long-term graft survival.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Platelet function is altered by autogenous vein grafts in the early postoperative months.

A new animal model was used to study the effect of autogenous vein grafts on platelet function and to follow the time course of any changes. Reversed external jugular vein was grafted to the ipsilateral carotid artery in lop-eared rabbits. The platelet activation index (PAI), a measure of platelet responsiveness to adenosine diphosphate, was used to measure the effect of the graft on platelets at set postoperative times and the results compared with pre-operative values. There was a statistically significant increase in PAI in samples taken from the central ear artery at 1 week (P less than 0.005), 1 month (P less than 0.005) and 2 months (P less than 0.05) after operation, but not at 4, 6 and 8 months. In animals killed 1 week and 1 month after operation, platelets were shown to be activated following a single passage across the graft. Platelets that have been activated by the graft may in turn be involved in the process of intimal hyperplasia in the graft wall. Our results suggest that modification of the behaviour of activated platelets by drug intervention may only be required during the early postoperative months.

Adenosine Diphosphate↗
PubMed1984

Activation of platelets by autogenous vein grafts is not prevented by acetylsalicylic acid and dipyridamole.

We have shown previously that experimental autogenous vein grafts activate platelets for up to four months following operation. In the present study, animals were treated with middle dose ASA (10 mg X kg-1 X 24 h-1) plus dipyridamole (8 mg X kg-1 X 24 h-1) and followed for 8 months. Despite this treatment, platelets were activated by the vein graft for up to four months after operation but not after this time. Similarly, treatment with low dose ASA (0.5 mg X kg-1 X 24 h-1) plus dipyridamole (8 mg X kg-1 X 25 h-1), high dose ASA (40 mg X kg-1 X 24 h-1) plus dipyridamole (8 mg X kg-1 X 24 h-1), or dipyridamole alone (8 mg X kg-1 X 24 h-1), did not prevent the vein graft-induced activation of platelets. Full inhibition of platelet arachidonic acid metabolism was demonstrated in the high dose ASA plus dipyridamole group. These results suggest that the interaction between the vessel wall and platelet is not inhibited by ASA plus dipyridamole. Platelets have first to be activated before causing intimal hyperplasia. Since aspirin and dipyridamole did not prevent activation of platelets by the graft, this drug combination is unlikely to prevent the development of intimal hyperplasia in the graft wall.

Adenosine Diphosphate↗
PubMed1984

Intimal thickening in autogenous vein grafts in rabbits: influence of aspirin and dipyridamole.

The effects of three different platelet modifying regimens on the degree of intimal thickening of autogenous vein grafts in rabbits were measured one month after operation. Dipyridamole alone (2 mg/kg/6 h) had little effect on the intimal thickness of these rabbits compared with that of controls (mean (1 SEM) for treated animals: 72.0 (7.9) micron; controls: 63.6 (6.0) micron). High dose acetylsalicylic acid (40 mg/kg/24 h) plus dipyridamole (2 mg/kg/6 h) increased intimal thickening significantly (85.8 (6.0) v 63.6 (6.2) micron; p = 0.05, n = 17). Low dose acetylsalicylic acid (0.5 mg/kg/24 h) plus dipyridamole (2 mg/kg/6 h) also increased intimal thickening (79.0 (6.1) v 63.6 (6.0] micron but not to a significant degree. It has previously been shown in vitro that acetylsalicylic acid increases the area of an exposed subendothelial arterial surface covered by platelets. Such an effect may explain our finding of increased intimal thickening with high dose acetylsalicylic acid plus dipyridamole.

Animals↗
PubMedDate not supplied

Creatine kinase MB isoforms: a potential predictor of acute cardiac allograft rejection.

BACKGROUND: Noninvasive studies to detect or predict acute allograft rejection after heart transplantation have failed to be sufficiently reliable to substitute for endomyocardial biopsy. Isoforms of creatine kinase MB isoenzyme (MB2 and MB1) are extremely sensitive markers of ischemic myocardial damage and, in theory, may be elevated in cardiac allograft rejection when myocardial necrosis is visible on microscopy (International Society for Heart and Lung Transplantation grade 2 or greater). METHODS: We examined, prospectively, the endomyocardial biopsy specimens (n = 256) of 50 consecutive patients undergoing orthotopic heart transplantation. Blood samples for creatine kinase MB isoforms (n = 527) were taken immediately before endomyocardial biopsy and at intervals between biopsies. RESULTS: The median ratio of MB2/MB1 in plasma samples taken at the time of biopsy for grades 2 and 3 was not significantly different from the ratio from biopsy specimens graded 0 and 1 (1.65 versus 1.33; p = Not significant). The sensitivity for diagnosing a moderately severe rejection was 47% with a specificity of 58%. However, in patients with significant acute rejection (grades 2 and 3) in whom consecutive samples were collected, the MB2/MB1 ratio was significantly increased before histologic changes seen on biopsy in 13 of 16 rejection episodes by a mean of 14 days. The sensitivity for predicting rejection (grade 2 or 3) before endomyocardial biopsy was 60% with a specificity of 71% (positive predictive value 43%, negative predictive value 86%). CONCLUSIONS: Creatine kinase MB isoforms may predict the occurrence of acute rejection before histologic evidence seen on endomyocardial biopsy.

Adolescent↗