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Biomedical subjects

A J Bryan

Publications and source records attributed to A J Bryan.

At least 73 records · Page 4Linked to original sources
PubMed1995

In-hospital audit underestimates early postoperative morbidity after cardiac surgery.

BACKGROUND: The demand for open heart surgery has driven current practice towards early postoperative discharge and interhospital transfer to maximise patient throughput. The extent to which this redirects morbidity to other healthcare providers is unknown. OBJECTIVE: To define the incidence of inhospital and early postoperative morbidity within 6 weeks of primary hospital discharge after cardiac surgery. DESIGN: Prospective inhospital data for 322 consecutive adult patients undergoing cardiac surgery were compared with retrospective information obtained by postal questionnaire. RESULTS: Mean (SD) primary postoperative hospital stay was 8.3 (3.1) days. There were 13 inhospital deaths (4%), and three patients died within 6 weeks of primary discharge. Retrospective information was obtained from 297 patients (96%). Of these, 77% patients were discharged home directly, while 23% were transferred to other hospitals for continued medical care. Mean (SD) hospital stay after transfer was 12 (8.4) days and required 741 additional hospital bed days. Thirty nine patients (13%) were readmitted to hospital, requiring a further 275 hospital bed days. The readmission rate was lower in patients sent home directly (10%), than in those who were transferred (22%; P < 0.001). CONCLUSIONS: Inhospital audit underestimates early morbidity after cardiac surgery. The burden transferred to other healthcare providers is considerable and has important financial implications for purchasers.

Cardiac Surgical Procedures↗
PubMed1995

Cardiopulmonary bypass perfusion temperature does not influence perioperative renal function.

BACKGROUND: The recent introduction of normothermic cardiopulmonary bypass (CPB) perfusion has raised concerns regarding the associated risk of renal dysfunction through its potential to exacerbate the systemic inflammatory response and end-organ injury. This study was designed to investigate the influence of CPB perfusion temperature on renal function. METHODS: A prospective, randomized, controlled trial of CPB perfusion temperature (28 degrees C, 32 degrees C, and 37 degrees C) was performed in 30 patients undergoing routine coronary artery bypass grafting with normal preoperative renal function. Creatinine clearance was measured before induction of anesthesia, during CPB, and during every 12-hour period thereafter for 48 hours postoperatively. Glomerular and tubular function were assessed further by measurement of urinary creatinine, albumin, total protein, and retinol binding protein levels preoperatively, during CPB, and on days 1 and 3 postoperatively. RESULTS: Creatinine clearance increased on CPB by 51% (28 degrees C), 185% (32 degrees C), and 112% (37 degrees C) (all p < 0.01 versus preoperative values) and returned to preoperative values by 24 hours postoperatively in all three groups. Urinary albumin/creatinine ratios rose significantly from a mean of 0.4 +/- 0.1 (standard deviation) to 10 +/- 12.5 (28 degrees C), from 0.55 +/- 0.3 to 5.2 +/- 4.9 (32 degrees C), and from 0.96 +/- 0.8 to 7.8 +/- 7.0 (37 degrees C) during CPB (all p < 0.001) but decreased gradually thereafter. Also, urinary total protein/creatinine ratios rose significantly from a mean of 0.009 +/- 0.007 to 0.034 +/- 0.02 (28 degrees C), from 0.01 +/- 0.006 to 0.026 +/- 0.01 (32 degrees C), and from 0.011 +/- 0.008 to 0.033 +/- 0.02 (37 degrees C) during CPB (all p < 0.005); however, there was a further increase by 24 hours, and ratios decreased gradually thereafter. Similarly, urinary retinol binding protein/creatinine ratios rose significantly in all three groups during CPB (all p < 0.0001) and increased further by 24 hours. There was no statistically significant difference between the renal markers in the three temperature groups in any of the observations. CONCLUSION: These data suggest that cardiopulmonary bypass perfusion temperature does not influence renal function in patients undergoing coronary artery bypass grafting.

Aged↗
PubMed1995

Thrombolytic therapy for left sided prosthetic heart valve thrombosis.

In order to clarify the role of thrombolytic therapy for the treatment of left sided prosthetic valve thrombosis, a composite analysis of 158 cases reported in the English literature was undertaken. Complete success of therapy was achieved in 68.4% of patients, and the results were better in patients with aortic compared to mitral valve prostheses (p < 0.01), in those presenting in lower NYHA class (p < 0.01), and with acute rather than chronic symptoms (p < 0.05). A successful outcome was seen more frequently with tilting disc than bileaflet valves (p < 0.001). Overall mortality during therapy was 7%. Cerebral embolic events were observed in 9.5% of patients, and irreversible neurological injury occurred in 4.4%. The rethrombosis rate was 17% and the incidence of late death was 6.3%. Thrombolysis may be a useful therapeutic alternative for left sided prosthetic valve thrombosis in patients with a perceived contraindication to surgery. The risks of systemic clot embolization along with incomplete resolution of valve leaflet motion or rethrombosis limits any recommendation for more widespread use.

Adult↗
PubMed1995

Aprotinin use with hypothermic circulatory arrest for aortic valve and thoracic aortic surgery: renal function and early survival.

BACKGROUND AND AIM OF STUDY: Aprotinin is widely used during high risk cardiac surgery to reduce blood loss. Concern has been expressed about the safety of aprotinin in association with hypothermic circulatory arrest for surgery of the thoracic aorta and aortic valve. METHODS: A consecutive series of 19 patients undergoing surgery of the ascending aorta and/or the aortic arch using hypothermic circulatory arrest (15 - 20 degrees C) in conjunction with the use of aprotinin were studied prospectively from January 1993 to October 1994. The indications for operation were aortic dissection (n = 15) (11 acute) or annuloaortic ectasia (n = 4); 11 were emergency procedures. Ten patients underwent aortic valve replacement as part of a composite aortic root replacement and in seven patients aortic valve resuspension was possible. RESULTS: Mean total chest tube drainage was 878 +/- 548 ml (range 300 - 2,000 ml) with a mean usage of homologous blood of 2,328 +/- 1,600 ml. All but one patient survived (mortality 5.3%). None of the survivors experienced any adverse cardiac or neurological events. Serum creatinine rose significantly from a mean of 102 +/- 17 micromol/L preoperatively, to a mean of 172 +/- 100 micromol/L postoperatively (p<0.05), however, none of the patients became anuric or required dialysis and all values returned to preoperative levels by six weeks after surgery. Median intensive care stay was two days (range 1 - 20 days) and the median postoperative hospital stay was 11 days (range 6 - 50 days). CONCLUSION: These data suggest that aprotinin in conjunction with hypothermic circulatory arrest for surgery of the thoracic aorta and aortic valve has no adverse effect on early survival. However, significant though transient postoperative renal dysfunction was commonly observed in our experience.

Adult↗
PubMed1994

Transesophageal echocardiographic measurements of cardiac output in cardiac surgical patients.

Transesophageal echocardiography is becoming increasingly popular as a method of intraoperative monitoring because it can be performed continuously, does not transgress the sterile operative field, and provides data with regard to valve function, ventricular volumes, and contractility. Recently it was suggested that it can be used to measure cardiac output; however, controversy remains regarding its accuracy. Cardiac output was measured simultaneously by transesophageal echocardiography (using a 5-MHz pulse-wave Doppler, single-plane viewing probe) and by the thermodilution method in 21 patients undergoing open heart operations. The cardiac outputs measured by thermodilution correlated poorly (r = 0.45) with the transesophageal values derived from the left ventricular cross-sectional area, and the mean difference was 0.47 +/- 2.17 (standard deviation) L.min-1, giving limits of agreement of from -3.87 to +4.81 L.min-1. Cardiac outputs measured by thermodilution correlated well (r = 0.95) with transesophageal Doppler values derived from pulmonary artery flow velocity, with a mean difference of 0.12 +/- 0.45 L.min-1 and narrow limits of agreement of from -0.78 to +1.02 L.min-1. Based on our findings, transesophageal Doppler echocardiographic determination of cardiac output using pulmonary artery flow measurements can provide accurate hemodynamic data in patients undergoing cardiac operations.

Aged↗
PubMed1994

Echocardiographic evidence of persistent pericardial effusion after open heart surgery.

Cross-sectional and M-mode echocardiography were used to review 33 patients 6-28 months (mean 19 months) after open heart surgery. Eleven patients had had echocardiographic signs of pericardial effusion during the first week after open heart surgery (Group A), and 22 had not (Group B). At review, pericardial effusion was found in 73% of subjects in Group A compared with 18% of those in Group B (P < 0.01). On average, posterior effusions were small (mean dimension in systole 0.9 cm) but they were detected reproducibly (interobserver agreement 97%). Anterior echo-free spaces (< 0.5 cm) were found frequently, but interobserver variation in their detection was high (agreement in 68%). Symptoms did not correlate with the presence of a late post-operative effusion but the groups were not matched for rhythm or ventricular function. Five patients in Group A had developed atrial fibrillation in association with their early post-operative effusion, and four of these had persisting atrial fibrillation at this review. These results suggest that echo-free spaces around the heart, suggestive of small pericardial effusions, may persist for many months after open heart surgery.

Cardiac Surgical Procedures↗
PubMed1994

The biology of saphenous vein graft occlusion: etiology and strategies for prevention.

Saphenous vein graft failure remains a significant clinical and economic burden. Although increased use of arterial conduits has improved long-term outcome, the majority of bypass procedures continue to use saphenous vein. Early vein graft patency is maximized by avoiding damage at the time of implantation, meticulous surgical technique, and appropriate use of antithrombotic therapy. No surgical technique or pharmacological intervention, however, has been shown to prevent late occlusion, which results from the progression of intimal vascular smooth muscle cell proliferation and superimposed atheromatous changes. Over the last few years, there has been a dramatic increase in our understanding of the biology of the vessel wall and the cellular and humoral influences on the process of intimal vascular smooth muscle cell proliferation. This has been possible principally through the advancement and application of molecular biological techniques. Although pharmacological therapies to prevent intimal hyperplasia continue to be evaluated, it is again the new series of strategies made possible by molecular biology that provide the most exciting prospects for treatment. Development of specific antibodies, antisense oligonucleotides, and vascular gene transfer represent potentially effective therapies, not only for the prevention of vein graft failure but also for a whole range of cardiovascular diseases.

Cell Division↗
PubMed1994

Coronary artery bypass surgery: current practice in the United Kingdom.

OBJECTIVE: To assess current clinical practice in coronary artery bypass surgery and compare it with a previous survey conducted five years ago. SETTING: United Kingdom. DESIGN: Postal questionnaires were sent in March 1993 to 120 consultant cardiac surgeons currently performing coronary artery bypass surgery. 104 (87%) were returned by May 1993. RESULTS: The 104 surgeons who returned the questionnaire performed an estimated total of 25,234 coronary artery bypass operations in 1992 with an average case load per surgeon similar to that in 1987 (243 v 214, NS). The internal mammary artery was regarded as the conduit of choice by 101 surgeons (97%) and was used in 93% of bypass grafts to the left anterior descending coronary artery compared with 73% in 1987 (p < 0.001) but only in 7% of grafts to the circumflex and right coronary systems. There was also a significant increase in the number of surgeons using both internal mammary arteries (88% v 59%, p < 0.01) but only a small increase in those using the internal mammary artery as a sequential graft (55% v 44%, NS). The age of the patient remains one of the main contraindications to the use of the internal mammary artery (40%), together with insufficient mammary flow (42%), endarterectomy (22%), and unstable angina (17%). The right gastroepiploic and inferior epigastric arteries were used only occasionally (3%) when the internal mammary artery or the saphenous vein were not available. Most surgeons (96%) still advocate the use of aspirin to enhance graft patency, with 87% of surgeons continuing treatment indefinitely, compared with 50% in the previous survey (p < 0.001). As for methods of myocardial protection, 72% of surgeons used cardioplegic arrest whereas 28% preferred intermittent aortic cross clamping and fibrillation. CONCLUSIONS: It is the consensus among British cardiac surgeons that the internal mammary artery is the graft conduit of choice. Its use has been significantly extended over the past five years (1987 to 1992) suggesting a quick response to advancing scientific knowledge. The use of alternative arterial conduits is still limited, perhaps as a reflection of the relative lack of information on their long-term performance. The recently advocated technique of retrograde cardioplegia and continuous warm cardioplegia is not yet popular.

Age Factors↗
PubMed1994

Surgical priorities in the management of arteriopaths.

Coronary artery disease and its complications remain the leading cause of death in Western society. With an ageing population there is an increasing number of patients with severe multilevel atherosclerosis. Atheromatous disease affecting the coronary, carotid, abdominal aorta and peripheral vasculature may co-exist, and vascular surgical reconstruction is commonly indicated to more than one site. The investigation and sequence of surgical interventions to minimize morbidity and mortality in this group of patients are discussed.

Arterial Occlusive Diseases↗
PubMed1994

Hemodynamic effects and echocardiographic consequences of tension-free pericardial closure after heart valve surgery.

Pericardial closure early after open heart surgery has been shown to consistently lower cardiac output and stroke volume, while mean arterial blood pressure is maintained by an increase in systemic vascular resistance. In 10 patients (seven females) (mean age 65 +/- 4 years) undergoing an open heart valve procedure, the effects of a tension-free pericardial closure technique were studied using thermodilution studies and transesophageal echocardiography. The following variables were recorded: mean arterial pressure, mean pulmonary artery pressure, right atrial pressure, cardiac output, stroke volume, systemic vascular resistance, and systolic and diastolic left ventricular dimensions, and left ventricular wall thickness. Observations were made after the heart was decannulated, both while the pericardium was open and after it had been closed by a tension-free technique, and then after closure of the chest. Further observations were made while the chest remained closed, both before and after the pericardium had been reopened by removing the pericardial suture through the chest wall. Closing the pericardium with the tension-free technique while the chest remained open was followed by a fall in cardiac output by 8% and a 15% fall in systemic vascular resistance (both n.s.). These changes caused a 13% reduction in the mean arterial pressure (p = 0.03). Ejection fraction did not change, and systolic and diastolic left ventricular dimensions decreased by 6% and 4% respectively (both n.s.). Opening the pericardium (1.5 to 2 hours after the end of the operation) while the chest remained closed was not followed by significant change in any of the hemodynamic or echocardiographic variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗