Alf Holmgren

CLINICAL AND HAEMODYNAMIC RESULTS OF AORTIC VALVE REPLACEMENT WITH THE BJORK-SHILEY TILTING DISC VALVE PROSTHESIS

One hundred and one patients with aortic valve disease, aortic stenosis 29 patients, aortic insufficiency 29 patients and combined lesions in 43 patients, underwent valve replacement with the Bjork-Shiley tilting disc prosthesis. Early and late mortality rate 8% and 3% respectively. Six patients died in heart failure, 2 after a myocardial infarction, one due to cardiomyopathy, one of septicaemia and one due to carcinoma of the stomach. No thrombo-embolic complications were encountered.Fifty-seven of the patients were subjected to a follow-up study 6 to 8 months after surgery, including right and left heart catheterization. All these 57 patients were subjectively improved by the operation and 30/57 were considered to be in an excellent clinical condition.The heart volume in supine decreased on average 20% after operation. The exercise tolerance (Wmax) increased in 24/57 patients. There were marked decreases in left ventricular systolic and end diastolic pressures. Pulmonary arterial and right heart pressur...

Studies on the Relation between Mobilization of Free Fatty Acids and Energy Metabolism in Man : Effects of Norepinephrine and Nicotinic Acid

Abstract The magnitude of the increase in oxygen consumption produced by intravenously infused 1-norepinephrine in fasting young men was well correlated with the increase it produced in plasma level of free fatty acids. The calorigenic effect of norepinephrine was partially inhibited by prior injection of nicotinic acid in quantities sufficient to prevent its fat-mobilizing action. These findings, coupled with the failure of nicotinic acid to affect discernably the effects of norepinephrine on carbohydrate metabolism and cardiovascular and respiratory functions, support the concept that the calorigenic effect of norepinephrine results, in part, from mobilization and oxidation of free fatty acids derived from adipose tissue. Basal energy metabolism was not altered when plasma levels of free fatty acids were reduced by injections of nicotinic acid, but the respiratory quotient rose significantly. These observations suggest that the level of oxidative metabolism is not influenced appreciably in resting adult human subjects by the availability of free fatty acids as fuel and are compatible with the hypothesis that oxidation of carbohydrate is inhibited by utilization of free fatty acids in man.

Work capacity and central hemodynamics thirteen to twenty-six years after repair of tetralogy of Fallot.

Exercise tests and cardiac catheterization were performed in 53 patients, 13 to 26 years after intracardiac repair of tetralogy of Fallot. At the time of repair, the median age was 7 years, and 60% of patients with cyanosis had had a previous palliative procedure. The right ventriculotomy was closed without a patch in 21 patients (40%), a patch restricted to the right ventricle was inserted in 18 patients (34%), and in 14 (26%) the patch extended across the pulmonary anulus. At follow-up, 94% of the patients were free of symptoms. Symptom-limited work capacity was 87% of the predicted value (95% confidence limits, 82% to 94%). Work capacity was inversely related to age at follow-up, to right ventricular systolic pressure at rest, and to presence of moderate or severe pulmonary valve regurgitation. Cardiac output in relation to oxygen uptake was reduced in 74% of patients during exercise. In 12 patients (23%), systolic pressure at rest in the right ventricle was 50 mm Hg or higher. Systolic pressure during exercise in the right ventricle was lower in patients without a patch than in those with a patch and was abnormally high in all groups compared with healthy subjects. The ratio of right to left ventricular pressure was significantly lower than measurements taken immediately after repair. An intracardiac left-to-right shunt was present in 6 patients (11%). Three patients required invasive treatment as a result of our follow-up. We conclude that work capacity was moderately reduced 13 to 26 years after repair of tetralogy of Fallot and was adversely influenced by right ventricular hypertension and pulmonary valve regurgitation. Intermittent lifelong surveillance is advocated, because patients without symptoms may have hemodynamic abnormalities that necessitate intervention.

The Björk-Shiley tilting disc valve in isolated mitral lesions.

During the period September 1969 to August 1971, 103 consecutive patients underwent mitral valve replacement with the Bjork-Shiley tilting disc valve prosthesis. Forty-four of these patients had isolated mitral lesions. They were studied pre- and postoperatively in a long-term clinical and haemodynamic follow-up. The valve, which had a Delrin disc occluder and opened at an angle of 50°, was placed in a subannular position with isolated mattress sutures and with the larger opening directed towards the ventricular septum. Early and late mortality rates were 5 and 16%, respectively. Thrombo-embolic complications occured in 25% of the cases, half of which were without sequelae. All patients received anticoagulant treatment (Dicoumarol). Thirty-six patients were evaluated at this Clinic 6-12 months postoperatively and 30 of them were catheterized. Subjective improvement was seen in 34/36 and functional improvement (NYHA) in 30/36 patients. Careful haemodynamic evaluation revealed central circulatory improvment...

Central haemodynamics at rest and during exercise before and after aortic valve replacement with the Bjork - Shiley tilting disc valve in patients with isolated aortic stenosis.

A pre- and postoperative haemodynamic study at rest and during exercise was performed in 37/53 consecutive patients with isolated aortic stenosis operated upon with the Bjork-Shiley tilting disc valve. After operation there was a significant average decrease in heart volume in supine position and a significant increase in working capacity. Total haemoglobin decreased slightly, but blood volume remained unchanged as did the kinetics of circulation at rest and during exercise. Left and right ventricular pump function, as judged from systolic and end-diastolic pressures, mean atrial pressures and left ventricular systolic and diastolic work, was improved following operation. Marked reductions were found in left ventricular systolic pressures at rest and during exercise. Left ventricular end-diastolic, pulmonary artery and right heart pressures decreased significantly. Pulmonary vascular resistance remained unchanged. After operation the systolic aortic pressure and pulse pressure increased significantly duri...

Significance of position and opening angle of the Björk-Shiley tilting disc valve in mitral surgery.

The opening angle of the Bjork-Shiley mitral prosthesis was increased from 50° to 60° and the prosthesis rotated 180° in the mitral annulus to direct the downward moving part of the disc towards the posterior leaflet base, in an attempt to optimize the pressure-flow relationship of the prosthesis. The material for the disc occluder was changed to pyrolytic carbon and the new sewing ring had two flanges. Thirty-one consecutive patients with isolated mitral lesions were studied before and 5-12 months following mitral valve replacement. Prior to operation, 25/31 (81 %) of the patients were in N.Y.H.A. function class III or IV, 28/31 (90 %) were in atrial fibrillation, the central circulation was markedly hypo-kinetic and the left + and pulmonary artery pressures were markedly elevated.Early mortality within 1 month of operation was 6 %, while there was no late mortality after an observation period of 12-24 months. Subjective and N.Y.H.A. function class improvement was observed in 22/27 (82 %). Thrombo-emboli...

Pulmonary function thirteen to twenty-six years after repair of tetralogy of Fallot

Lung function was evaluated in 68 patients 13 to 26 (median 19) years after repair of tetralogy of Fallot. Age at repair was 7 years (9 months to 42 years) and 51% had a palliative shunt. An outflow patch was inserted in 56%. Median vital capacity was 84% of predicted, forced expiratory volume in 1 second 83%, maximal voluntary ventilation at 40 breaths/min 70%, and diffusing capacity for carbon monoxide 77% of predicted. Scintigraphy demonstrated abnormal pulmonary perfusion in 86%. Average right lung perfusion was 57% (predicted 52%). Regional hypoperfusion could in some patients be explained by previous palliative shunt, pulmonary artery obstruction, or presence of aortopulmonary collaterals. Median symptom-limited work capacity was 82% (95% confidence limits 78% to 90%) of predicted. Twenty-eight physically active patients had high values for symptom-limited work capacity, vital capacity, forced expiratory volume in 1 second, and maximal voluntary ventilation at 40 breaths/min compared with those of inactive patients. Lung function variables were related to physical exercise and previous palliative shunt. Moderate or severe pulmonary valve incompetence had negative but not significant influence on lung function. There was no significant influence of acyanosis before repair, use of transannular patch, duration of follow-up, or smoking. We found moderately reduced work capacity and lung function late after repair of tetralogy of Fallot that did not cause symptoms. Lung function variables were high in young active male patients and low in patients with previous palliative shunt. A better lung function in active patients indicates that physical activity should be encouraged after repair of tetralogy of Fallot.

The Björk-Shiley Mitral Valve Prosthesis: A Comparative Study with Different Prosthesis Orientations

Abstract Mitral valve replacement with the Bjork-Shiley tilting-disc valve was performed in 233 patients, 142 of whom were observed for more than 1 1/2 years. An isolated mitral valve lesion was present in 75 of the 142, and these patients were studied before and 5 to 13 months after operation. In 44 of the 75 the disc was made of Delrin, opened 50 degrees, and the prosthesis was rotated with the large orifice facing anteriorly. In the remaining 31 patients the disc was made of pyrolytic carbon, opened to 60 degrees, and the prosthesis was rotated posteriorly. Clinical improvement was similar in both groups of patients. Hemodynamic improvement at rest was similar in both groups, but during exercise the second group showed greater improvement. The main factor responsible for this better result in the second group was considered to be the prosthesis orientation, i.e., the large opening placed posteriorly, directing the bloodstream toward the parietal wall; the altered geometry of the inflow tract of the left ventricle was another possible factor.

WORKING CAPACITY AND CARDIOPULMONARY FUNCTION AFTER EXTENSIVE LUNG RESECTIONS

Twelve patients were investigated 7-168 months after pneumonectomy. Two of them had also undergone resection of a segment of the remaining lung. The follow-up included studies of working capacity, static and dynamic lung volumes, alveolar gas exchange, diffusing capacity, blood gases and central haemodynamics with right heart catheterization. The working capacity was markedly reduced, limited by dyspnoea in 10/12 patients. The dyspnoea was related to reduced static and dynamic lung volumes (50% of normal). The diffusing capacity of the remaining lung was half of that predicted for two lungs from total haemoglobin and age and the transfer capacity of the lungs for oxygen was loaded to its maximum even at submaximal loads, resulting in a decrease in arterial oxygen tension and saturation and an increase in the alveolo-arterial oxygen tension difference. The central circulation was hypokinetic at submaximal loads and the stroke volume was small. The reduction in working capacity was caused by a number of coacting factors, inactivity, reduced lung function and small stroke volume. It was not possible from the present investigation to single out any of these factors as the main cause of dyspnoea during exercise and thereby the reduced working capacity.

Evaluation of the 21 Mm Björk-Shiley Tilting Disc Valve in Patients with Narrow Aortic Roots: A Clinical, Haemodynamic and Angiographic Study

Nineteen out of 23 consecutive patients with aortic valvular lesions and narrow aortic roots, operated upon with the 21 mm Bjork-Shiley tilting disc valve prosthesis, were subjected to a clinical and haemodynamic pre- and postoperative study. An angiographic examination was carried out after valve replacement.The total mortality was 1/23 patients (4%). Clinical improvement was found in 17/19 patients (89%) after surgery. No thrombo-embolic episodes occurred during the follow-up period.The main response to aortic valve replacement was an obvious reduction of the pressure load of the left ventricle as indicated by the marked decreases in left ventricular systolic pressure and stroke work. These changes were most pronounced at rest and accompanied by reduction of distressing symptoms, increase in working capacity and decrease in cardiac enlargement. Unloading of the left ventricle after aortic valve replacement did not influence heart rate, heart rhythm, stroke volume and kinetics of the central circulation ...