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Biomedical subjects

E G Butchart

Publications and source records attributed to E G Butchart.

At least 37 records · Page 2Linked to original sources
PubMed1995

Arterial risk factors and ischemic cerebrovascular events after aortic valve replacement.

To assess the association of possible risk factors with ischemic cerebrovascular events after aortic valve replacement (AVR), 619 consecutive patients undergoing AVR with a Medtronic Hall valve between the beginning of December 1979 and the end of December 1992 and surviving the immediate postoperative period were analyzed. Possible risk factors examined were valve lesion, prosthesis size, postoperative functional status, systemic hypertension, cigarette smoking, diabetes, coronary artery disease and atrial fibrillation. There were 53 ischemic cerebrovascular events in 38 patients during 3,174 follow up years, yielding a linearized event rate of 1.7%/patient-year. Significant risk factors in terms of odds ratios (OR) were postoperative hypertension (OR 8.0), postoperative NYHA class III or IV (OR 5.5), postoperative smoking (OR 4.0), diabetes (OR 3.5), preoperative hypertension (OR 2.7) and preoperative smoking (OR 1.8). There was highly significant interaction between postoperative hypertension and postoperative smoking (OR 54.0). Eighty-one percent of patients who suffered events were hypertensive or smoking postoperatively or both. These findings have important implications for postoperative management and for the reporting of ischemic cerebrovascular events after valve replacement.

Adult↗
PubMed1994

The role of risk factors and trigger factors in cerebrovascular events after mitral valve replacement: implications for antithrombotic management.

To determine the effect of risk factors and trigger factors on cerebrovascular events, 622 patients who survived mitral valve replacement between December 1979 and December 1992 were analyzed. Ninety-six patients suffered 139 nonhemorrhagic cerebrovascular events. Data were available on 138 events in 95 patients. There were 32 transient ischemic attacks (TIAs), 57 reversible ischemic neurological deficits (RINDs), and 49 strokes. Age, sex, atrial fibrillation, left atrial size, systemic hypertension, and abnormal body mass index did not discriminate between patients who suffered events and those who did not. In contrast, smoking status differed significantly between patients who suffered events and those who did not. Among current or recent ex-smokers, the risk of stroke or RIND was significantly higher than in non-smokers (p < < 0.001). The odds ratio of suffering any type of event in patients who smoked at any time postoperatively versus those who did not smoke was 2.9 (95% confidence interval: 1.8 to 4.6). Of 61 patients contacted directly, 30% recalled an infective episode immediately prior to their event. A diurnal and seasonal influence on events was also detected with peaks in the morning and in the winter months, respectively (both p < 0.001). It is concluded that there is persuasive evidence for the involvement of several nonprosthetic factors in the incidence of cerebrovascular events after mitral valve replacement. This has implications for patient management and for future analysis of prosthetic heart valve series.

Atrial Fibrillation↗
PubMed1994

Preoperative staging of carcinoma of the bronchus: can computed tomographic scanning reliably identify stage III tumours?

BACKGROUND: The aim of preoperative computed tomographic (CT) assessment of patients with carcinoma of the bronchus is to stage the tumour accurately, and forewarn the surgeon of any possible local extrapulmonary extension of tumour in patients considered to have potentially resectable disease. The ability of CT scanning to differentiate between conventionally resectable lung cancer (TNM stages I and II), locally advanced but resectable lung cancer (TNM stage IIIa), and locally advanced but unresectable lung cancer (TNM stage IIIb) was determined in a group of patients accepted for surgery. METHODS: Computed tomographic scans of 110 patients who underwent thoracotomy for intended resection of carcinoma of the bronchus, including 52 cases with stage III and 58 cases with stage I or II disease, were reviewed and the CT features and radiological interpretations correlated with the surgical and pathological findings. RESULTS: Thirteen CT scans were judged not to have been of diagnostic quality: of the remaining 97 cases 45 had stage III lung cancer, of whom 30 had successful resections, and 52 had stage I or stage II tumours. There was no difference in the frequencies of CT observations--including contiguity of tumour and mediastinum or chest wall, apparent mediastinal or chest wall invasion, proximity of tumour to the carina, mediastinal nodal enlargement, pulmonary collapse or consolidation and pleural effusion--in patients with stage I/II disease and patients with stage III disease. Similar results were found when the same observations were compared in all patients with resected disease and those with unresectable tumour. Sensitivity and specificity of CT was 27% and 96% respectively for tumour unresectability, 50% and 89% for mediastinal invasion, 14% and 99% for chest wall invasion, and 61% and 76% for mediastinal nodal metastases. Only 19 of 45 stage III tumours were correctly identified as being stage III and resectable or unresectable. CONCLUSIONS: In patients being considered for thoracotomy for resection of lung cancer, CT scanning used as the sole method of staging is of limited value for differentiating between stage I/II and stage III tumours. Patients should not be denied the opportunity for curative surgery on the basis of equivocal CT signs.

Carcinoma, Bronchogenic↗
PubMed1994

Sudden death in a large prosthetic valve series based on a single prosthesis: experience with the medtronic Hall valve.

In order to test the validity of the current guidelines on the categorization of non-autopsied sudden death after valve replacement, a detailed analysis was undertaken of 412 deaths in a large single-institution prosthetic series based on one type of prosthesis (Medtronic Hall) over a 13-year period. Of 69 sudden or unwitnessed deaths, 48 (70%) were autopsied. There were no sudden deaths specifically related to the prosthesis itself, 79% of deaths were due to coronary disease or left ventricular dysfunction and 10% were due to intracranial hemorrhage. Overall, 90% of sudden deaths were unrelated to the prosthesis A seasonal fluctuation in the incidence of sudden and unwitnessed deaths was demonstrated in keeping with the known epidemiology of sudden death in the general population. It was concluded that there was no evidence to support the recommendation that all non-autopsied sudden deaths should be attributed to the prosthesis.

Cerebral Hemorrhage↗
PubMed1992

Computed tomographic assessment of patients following radical surgery for malignant mesothelioma.

Serial computed tomographic (CT) scans of the thorax and upper abdomen were performed in eight patients following radical surgery (pleuro-pneumonectomy) for diffuse malignant mesothelioma of the pleura. The post-operative appearances included a well defined membrane lining the pleuro-pneumonectomy space in seven cases; in two cases this resembled the original tumour. In six patients there was upward abdominal visceral displacement on the side of the surgery due to diaphragmatic resection; this resulted in contralateral mediastinal shift in four patients. One patient required a diaphragmatic prosthesis which produced a distinctive CT appearance. CT suggested recurrent mesothelioma in five cases. Although two patients had evidence of intrathoracic recurrence, in three patients the only feature was the non-specific finding of abdominal ascites. The normal CT appearances after pleuro-pneumonectomy should be recognized to facilitate radiological interpretation. With careful application CT is of value for the assessment of recurrent disease in patients following radical surgery for malignant mesothelioma.

Adult↗
PubMed1991

Traumatic rupture of the diaphragm: a difficult diagnosis.

Rupture of the diaphragm occurs in approximately 5 per cent of cases of severe blunt trauma to the trunk, and the mortality may be as high as 50 per cent. The diagnosis is important because of the high incidence of associated organ damage and complications of a missed injury. Successful diagnosis requires a high index of suspicion but can be made from the chest radiograph in 90 per cent of cases if visceral herniation has occurred. We present three cases of rupture of the diaphragm which highlight the frequent occurrence of a delayed or missed diagnosis.

Accidents, Traffic↗
PubMed1991

Neurilemmoma of the intrathoracic vagus nerve.

A neurilemmoma (Schwannoma) of the left intrathoracic vagus nerve was discovered on a chest radiograph of a 28 yr old woman and was removed via a left thoracotomy. Although neurogenic tumours are the most common tumours of the mediastinum, they rarely involve the intrathoracic vagus nerve.

Adult↗
PubMed1991

Adjusting anticoagulation to prosthesis thrombogenicity and patient risk factors. Recommendations for the Medtronic Hall valve.

In order to determine optimum anticoagulation levels for the Medtronic Hall valve, the effect of low anticoagulation (mean International Normalized Ratio [INR] 2.5, 1979-1984) and moderate anticoagulation (mean INR 3.0, 1985-1989) was determined in 345 patients (183 low, 162 moderate) undergoing isolated mitral valve replacement (MVR) and 241 patients (91 low, 150 moderate) undergoing isolated aortic valve replacement (AVR). There were no cases of valve thrombosis. Embolic events and bleeding events were graded in severity and multiple decrement event-free survival calculated according to valve site and anticoagulation level: MVR low, MVR moderate, AVR low, and AVR moderate. In the MVR low group, 80% were free of all events and 93% free of serious events at 3 years compared with 89% and 98%, respectively, in the MVR moderate group. The AVR low group experienced a very small incidence of embolic events (one only) and no bleeding events. The AVR moderate group suffered more bleeding and more embolic events and at 3 years only 87% were event-free compared with 99% in the AVR low group. In both AVR groups, all embolic events were associated with one or more known stroke risk factors. Patients under 70, in sinus rhythm who were normotensive and were nonsmokers suffered no embolic events irrespective of their anticoagulation level. We conclude that the optimum INR for the average Medtronic Hall patient is 3.0 after MVR and 2.5 after AVR but some adjustments may be required in relation to stroke risk factor analysis.

Aortic Valve↗
PubMed1989

Post-infarction ventricular septal defect: the importance of right ventricular coronary perfusion in determining surgical outcome.

Mortality from a post-infarction ventricular septal defect (VSD) can be reduced by surgery, selection for which would be helped by knowledge of factors affecting the postoperative prognosis. We reviewed our 9-year experience (1978-1987) of 40 surgically treated patients, comparing preoperative characteristics in those who died postoperatively (n = 15, 37%) and those who survived (n = 25, 63%), all still alive. Sex, age, infarct size as assessed by peak serum creatine kinase values, left ventricular end-diastolic pressure and pulmonary/systemic flow ratio (2.9 +/- 0.2 vs 3.1 +/- 0.3) were similar. Survivors had a lower incidence of inferior infarct than those who died (6, 24% vs 9, 60%, P less than 0.05), a lower incidence of cardiogenic shock (7, 28% vs 10, 67%, P less than 0.05), less elevation of right ventricular end-diastolic pressure (10.1 +/- 0.9 vs 14.7 +/- 1.0 mm Hg, P less than 0.01) and less impairment of right ventricular coronary supply as determined by a coronary angiography-derived myocardial score (0.9 +/- 0.3 vs 4.7 +/- 0.7, P less than 0.001). The data suggest that right ventricular coronary perfusion influences prognosis. The proposed angiographic score may help to identify preoperatively those patients most likely to benefit from surgery.

Cardiac Catheterization↗
PubMed1988

Anticoagulation variability between centres: implications for comparative prosthetic valve assessment.

One of the major determinants in the choice of a mechanical prosthetic valve is that valve's thromboembolic record but the thromboembolic (TE) rates may be substantially influenced by the levels of anticoagulation achieved. A detailed study of anticoagulation variability was undertaken in 834 patients who received one or more of a particular prosthesis (Medtronic-Hall) in one centre during a 7-year period from 1979 to 1987, but who attended 27 different anticoagulant clinics spread over a wide area. In addition, a questionnaire was sent to all 89 practising cardiac surgeons in the UK asking for their preferred range of International Normalised Ratio (INR) for patients with mechanical prosthetic valves. Both the local study (with 16,866 INR observations) and the national questionnaire (with a 53% response) revealed an enormous amount of variability. Median INR values (semi-interquartile range) varied from 2.2 to 3.9 (0.8-2.5) according to the anticoagulant clinic attended. The range of INR preferred by UK cardiac surgeons, but presumably not necessarily achieved, varied from 1.8-2.2 to 3.0-4.8, with 64% of surgeons preferring an INR less than 3.0. In comparison, standard US practice is to maintain prothrombin times equivalent to INR values of 4.0-5.0. Unless anticoagulant practice can be standardised internationally, comparison of TE complications between centres is meaningless, and casts doubt on the validity of TE rates quoted for particular prostheses, unless accompanied by a detailed analysis of anticoagulant control.

Anticoagulants↗