An improved pivotal disc-type prosthetic heart valve.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to K V Hall.
Explore the source record for details and available documents.
The in situ vein bypass technic for femoropopliteal atherosclerotic disease is described. Several factors influence the long-term results, the most important being a history of myocardial disease, the size of the vein graft, and sufficient runoff.
Explore the source record for details and available documents.
In aorto-coronary saphenous bypass grafts, peroperative flows measured by electromagnetic flowmetry were studied at rest and after injection of papaverine to reduce vasomotor tone. The results were correlated to graft patency approximately 14 months after operation and showed that patent grafts had greater flow values, both at rest and after papaverine, than grafts which were occluded at the re-examination. There was, however, considerable overlapping between the two groups, and no clear distinction between flow values in successful and unsuccessful grafts either at rest or after papaverine was found. No correlations were demonstrated between peroperative graft flow on one hand and the presence or absence of ventricular dyskinesia or electrocardiographic evidence of previous transmural myocardial infarction on the other.
To assess the haemodynamic effects of aorto-coronary saphenous vein bypass grafting, pre- and post-angiographic left ventricular end-diastolic pressure (LVEDP) and ejection fraction (EF) were measured before and in average 14 months after surgery in 80 patients. Symptomatic improvement occurred in 91% (73 of 80). In 43 patients with patent graft(s), pre-angiographic LVEDP and EF were unchanged (p always greater than 0.05), while postangiographic LVEDP was significantly reduced. Unchanged pre- and postangiographic LVEDP and EF were observed in 28 patients with double or triple grafts, with at least one graft patent and the other(s) occluded. Unchanged pre- and postangiographic LVEDP and reduced EF were observed in 9 patients with occluded single, double or triple grafts. We conclude that successful aorto-coronary saphenous vein bypass surgery in general does not improve resting left ventricular performance, but that the beneficial effect on left ventricular function can be demonstrated after a stress test such as ventriculography. A single graft to the left anterior descending artery seems to be of particular importance in this connection. On the other hand, deterioration was evident after unsuccessful surgery, particularly in patients with occlusions of 2 or 3 grafts. Digitalis therapy after operation or electrocardiographic indices of postoperative myocardial infarction apparently did not influence left ventricular performance.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Thirty-four patients were re-examined 12-24 months after mitral valve replacement with the Lillehei-Kaster pivoting disc valve prosthesis. There was an improvement of the kinetics with a significant decrease in arteriovenous oxygen difference compared with oxygen consumption. Cardiac output and stroke volume remained abnormally low, not differing significantly from pre-operative values. Resting pulmonary wedge pressure, pulmonary arterial pressure and pulmonary vascular resistance decreased significantly after operation. Mean values for these parameters remained slightly above normal. Exercise produced a rise in pulmonary wedge pressure, which could be explained partly by a simultaneous deterioration of the left ventricular function, as indicated by high end-diastolic pressures, and partly by a degree of obstruction to the foreward flow at the mitral valve itself. The rise in pulmonary wedge pressures led in turn to increased pulmonary arterial pressure, the latter being aggravated in some patients by a rise in pulmonary vascular resistance. Cardiac output increased during exercise, but usually to a lesser extent than was anticipated from the increase in oxygen consumption. The changes in cardiac output during exercise were due to an increase in heart rate, while stroke volume remained unchanged. The mean diastolic pressure difference across the prosthesis was 8.6 mmHg at rest and 12.7 mmHg during exercise. Subjective improvement and reduction in heart volume, as noted in the present series, corroborated the benificial effect of the operative procedure. The valve were all competent, as judged by cinéangiography, except in a few patients, in whom a small valvular or paravalvular leakage was seen. No thrombo-embolic episodes were recorded during the follow-up period.
Twelve out of 14 patients with aneurysm of the proximal ascending aorta (AA) combined with aortic valve incompetence (AI) were operated upon by replacement of both the aneurysm and valves by prostheses. Eight of the patients operated on (67%) survived and are living free of symptoms 3 months to 3 years after operation. The operative technique and complications are discussed.
A comparison is made between the clinical and haemodynamic results after mitral valve replacement with the Lillehei-Kaster and the Björk-Shiley disc valve prostheses, which were used alternatively in 54 patients with isolated mitral valve disease. No difference in functional improvement in the two groups was noted. Haemodynamic studies indicated a striking decrease in left atrial and pulmonary artery pressure, irrespective of the type of prosthesis inserted. Cardiac output incresed after operation, but was significantly different from the pre-operative value only in patients with the Björk-Shiley prosthesis, which also had a more favourable relationship between cardiac output and oxygen uptake during excercise than the Lillehei-Kaster prosthesis. One major advantage of the Björk-Shiley prosthesis is probably its favourable ration between tissue diameter and orifice area in contrast to the relatively large seating ring with a more unfavourable corresponding ratio in the Lillehei-Kaster prosthesis. In addition, the former valve possesses a more definite ability to increase its effective valve area during exercise.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Clinical and hemodynamic results have been evaluated 12--24 months after mitral valve replacement with the new Björk-Shiley tilting disc valve prosthesis. After operation, most patients were improved symptomatically and were classified as I-II (N.Y.H.A.). No patient became worse. Hemodynamic status at rest showed significant reduction in pulmonary capillary venous pressure, pulmonary artial pressure and significant increase in cardiac output when compared with the preoperative values, but postoperative hemodynamic abnormalities remained. Exercise produced a rise in pressures in the pulmonary circuit and in cardiac output. The increase in cardiac output was less than expected from the increase in oxygen consumption, with a few exceptions. Apparently, there was no close relationship between the symptomatic improvement and the hemodynamic results. Thus, the present study points to the importance of hemodynamic data in the objective assessment of the results of cardiac surgery.
Between May 1969 and June 1975, 43 patients with d-transposition of the great arteries, ranging in age from 2 months to 13 years (mean 19 months), underwent surgical correction. In the first 3 patients Mustard's original method was followed. Later a modified procedure was performed using a Teflon patch. Forty-two of the 43 patients had previously had 50 various palliative procedures, of which 30 were balloon atrial septostomy only. Five patients died in hospital (up to 5 weeks after operation). Of the 32 patients with simple repair of transposition of the great arteries (including 3 with ligation of a persistent ductus arteriosus), 3 died. One patient died as a result of complete AV block, one as a result of renal damage associated with unrelieved coarctation of the aorta, and one of cerebral infarction and peritonitis which probably were initiated preoperatively. Six patients who had additional surgery for pulmonary stenosis survived, including 3 patients who had closure of ventricur septal defect, including 2 who had debanding of the pulmonary artery, 2 died in a low cardiac output state. One infant operated on for subpulmonary stenosis developed permanent complete AV block and was successfully treated with a pacemaker. All the patients with combined operations had some problems postoperatively. The survivors improved greatly, but 2 patients died suddenly one, and one and a half years after the operation respectively.
Over the period 1958 to 1972 14 patients with traumatic arteriovenous fistulas were treated. The mean period from trauma to surgical closure of the fistula was 13.3 years. No form of reconstructive vascular surgery had been performed initially. The dominating symptom of arteriovenous fistula was a pulsating tumor with a marked thrill. Excision of the fistula and reconstruction of the artery and vein was performed in 11 patients. In 3 patients the fistula was first ligated resulting in early recurrence of the shunt. At follow-up 3-15 years postoperatively all fistulas were closed, but 5 patients had moderate symptoms.