Viking Olov Björk

A New Tilting Disc Valve Prosthesis

A new tilting disc valve is described. It is a free-floating delrin disc which tilts open to an angle of 60°. The gradient is negligible and much smaller as compared with ball and non-tilting valves in the aortic area. As the disc is not overlapping, blood trauma is minimal. The heart sounds are nearly normal. No diastolic and in most cases only a minimal systolic murmur is heard. 45 cases have been followed up to 6 months.In 1969, when we have had excellent results for up to seven years with ball valve prosthesis and 3 years with disc valves (Kay-Shiley) in the aortic root, there is still an urgent need to improve the artificial valves, both as regards the haemodynamics and long term results.

Brain Damage in Children after Deep Hypothermia for Open-heart Surgery

MATERIAL The material is divided into five groups according to the different surgical techniques used for extracorporeal circulation (Table I). GROUP 1.-Deep hypothermia was obtain..d bv extracorporeal cooling after the method of Drew and Anderson (1959). The blood was drained from the left atrium to a reservoir and pumped through a heat exchanger back to the femoral artery. When the heart fibrillated, usually between 16° and 30° C. oesophageal temperature, blood was drained from the right atrium to a reservoir and then pumped through a catheter in the pulmonary artery via the right ventricle, oxygenated in the patients lungs and returned to the reservoir draining the left atrium. When an oesophageal temnperature of between 5.8 and 14.7° C. had been reached, the circulation was stopped and the operation done in a bloodless flaccid heart. Rewarming

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...

The Pyrolytic Carbon Occluder for the Björk-Shiley Tilting Disc Valve Prosthesis

One years clinical experience with 103 Bjork-Shiley tilting disc heart valves, which have pyrolytic carbon discs, is reported. Complete clinical follow-up has shown no contra-indications to the use of pyrolytic carbon as the disc material for the Bjork-Shiley heart valve. In-vitro and in-vivo studies have shown that Delrin has excellent durability and wear characteristics as well as bio-compatibility and thromboresistance. However, its propensity to absorb moisture during steam autoclaving may lead to temporary, irregular valve function if proper drying instructions are not followed. Therefore, because pyrolytic carbon is totally unaffected by steam autoclaving, and also because of its other important characteristics, a series of 103 valves was implanted. Based upon the excellent experimental and clinical data derived, and in view of the advantages offered by pyrolytic carbon, we believe that the clinical use of this material should be expanded.

Management of Thrombo-Embolism after Aortic Valve Replacement with the Björk-Shiley Tilting Disc Valve: Medicamental Prevention with Dicumarol in Comparison with Dipyridamole—Acetylsalicylic Acid. Surgical Treatment of Prosthetic Thrombosis

Dicumarol anticoagulation poved very effective in the prevention of thromboembolic complications after aortic valve replacement with the Björk-Shiley tilting disc valve. We have, however, encountered six late deaths because of massive cerebral hemorrhage, which represent 3% of the patients who were maintained on dicumarol medication at that time. This unacceptable mortality prompted us to introduce two programmes, one without anticoagulation and another one with dipyridamole-acetylsalicylic acid. Furthermore, dicumarol was terminated in patients with haemorrhagic episodes, instable anticoagulation, pregnancy, and in those reguiring surgery. The results were disappointing, however, and the majority of the patients involved were therefore put on dicumarol medication. Eleven of the 64 consecutive patients taking dipyridamole - acetylsalicylic acid had thrombo-embolic episodes during a mean follow-up period of 9 months...

Ruptured Sinus of Valsalva Aneurysms

Ruptured aneurysms of the aortic sinuses of Valsalva have been a surgical rarity at the Karolinska Hospital. Only nine such cases were operated on over a 13-year period (1968-1971). All nine aneurysms were of congenital type. They originated in the right coronary or the non-coronary sinus and drained into the right ventricle or the right atrium. All five ventricular entries were combined with a VSD in the membranous septum. No patient was in critical condition, despite significant left-to-right shunt and reduced aortic diastolic pressure. Aortic root angiography conclusively demonstrated the rupture per se, but even complete invasive examination failed to reveal two VSDs which were detected at surgery. Coexistent cardiac defects (5 VSDs, one ASD and one infundibular pulmonic stricture) were corrected in conjunction with the aneurysmal repair. The aneurysm was closed at its base. Isolated patched mattress sutures were always used. If tension-free approximation seemed unlikely, a patch was instead stitched to the margin of the defect. Reoperation was required in two cases because of recurrent fistulation. No patient died and the prognosis after repair appeared to be good. The transaortic supravalvular approach is preferred as the anatomically safest way to obtain closure at the aneurysmal base. A probe passed through the defect may help to identify the chamber of entry. A VSD is most likely to be present if the rupture drains into the right ventricle. These coexistent VSDs are often located in the membranous septum and they may be amenable to transaortic or transatrial repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Early and Late Patency of Aortocoronary Vein Grafts

Early patency (two weeks) of 331 aortocoronary vein grafts was 89%. Late patency (one year) of 122 restudied grafts was 80%. A cumulative one year patency of 72% was calculated. Patency was similar for SV grafts, sutured distal to stenosis and segmental obstruction. Early patency was significantly decreased when the peroperative graft blood flow was 20 ml/min or less or the diameter of the recipient coronary artery was smaller than 1.5 mm. Cumulative one year patency was lower in symptomatic patients (54%) than in those who underwent consecutive reevaluation (80%). There was a trend towards improved patency rates for graft anastomosed to the left anterior descending coronary artery and grafts without pre-existing pathological changes. Patient parameters, such as at operation, sex, smoking habits, hypertension, lipid abnormalities, diabetes, previous myocardial infarction or depressed left ventricular function, had no bearing on patency. Graft failure occurring, despite refined surgical technique, is usually due to pathological changes of the vein graft per se or the recipient coronary artery and its vascular bed.

The Improved Bjórk-Shiley Tilting Disc Valve Prosthesis

The Björk-Shiley valve has been improved in three respects: (1) Increased strength by making the inlet strut an integral part of the orifice ring and doubling its cross-section area; (2) Improved hydrodynamics; (3) Elimination of the area of stagnant and low flow behind the disc. By utilizing a convexo-concave disc and by moving the pivot point downstream, the disc in open position is moved further out of the orifice ring. The flow through the smaller hole is thus increased by 40%. A significant clearance is obtained between the disc and the valve ring in open position. 234 of these valves have been inserted and followed-up for a maximum period of two years with excellent results.

The evaluation of the degree of mitral insufficiency by selective left ventricular angiocardiography

Abstract The evaluation of the degree of the regurgitation through the mitral orifice by comparison of the left atrial and aortic contrast filling after the injection of contrast into the left ventricle is considered to be the best method available. Five stages with regard to how far the contrast has passed into the aorta when the left atrium is completely filled with contrast have been established. The findings at operation in 13 cases were in agreement with our evaluations. We are convinced that in cases in which the left atrium is completely filled when the contrast has reached only the top of the aortic arch, or not that far, no closed operation should be performed on the mitral valves.

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.