Combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis. Early and late results in 75 consecutive patients

Relation between choice of prostheses and late outcome in double-valve replacement

The purpose of this study was to determine if the combination of a mechanical and bioprosthetic valve in the aortic and mitral positions influences late morbidity and mortality when compared with patients who had dual mechanical or dual bioprosthetic valves inserted. We reviewed the course of 89 hospital survivors of combined aortic and mitral valve replacement. The mean postoperative follow-up interval was 6.6 years, with a total follow-up of 583 years (98% complete). At 12 months after operation, mean functional class decreased from 3.1 to 1.7 (p < 0.05) and mean cardiac index increased from 2.1 to 2.5 L.min-1.m-2 (p < 0.05). Actuarial survival for the 89 patients (exclusive of < 30-day or in-hospital mortality, 14%) was 70%, 51%, and 33% at 5, 10, and 15 years. Freedom from reoperation was 93%, 78%, and 68%, and freedom from combined thromboembolism and anticoagulant-related hemorrhage was 82%, 60%, and 50%. These results show that there was no difference in overall survival in patients with dual mechanical valves, dual bioprosthetic valves, or a combination of both types at 15 years. There was, however, a lower reoperation rate in the group with dual mechanical valves as compared with the group with dual bioprosthetic valves (p < 0.05 at 10 years) or with a combination of valves (p < 0.05 at 15 years). The higher the number of mechanical valves the higher the combined risk of thromboembolism and anticoagulant-related hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of prosthetic mitral valve geometry and orientation on flow dynamics in a model human left ventricle

Pulsatile flow dynamics through bileaflet (St Jude and Duromedics), tilting disc (Bjork-Shiley and Omniscience), caged ball (Starr-Edwards), pericardial (Edwards) and porcine (Carpentier-Edwards) mitral valves in a model human left ventricle (LV) were studied. The model human ventricle, obtained from an in situ diastolic casting, was incorporated into a mock circulatory system. Measurements were made at various heart rates and flow rates. These included the transvalvular pressure drop and regurgitation in percent and cm3 beat-1. The effect of valve geometry and the orientation of the valve with respect to the valve annulus was analyzed using a flow visualization technique. Qualitative flow visualization study indicates certain preferred orientations for the tilting disc and bileaflet valve prostheses in order to obtain a smooth washout of flow in the LV chamber.

Clinical and necropsy observations early after simultaneous replacement of the mitral and aortic valves

Clinical and necropsy findings are described in 54 patients, aged 25 to 83 years (mean 53), who died within 60 days of simultaneous replacements of both mitral and aortic valves. The patients were separated into 4 groups on the basis of the presence of stenosis (with or without associated regurgitation) or pure regurgitation of each valve: 30 patients (56%) had combined mitral and aortic valve stenosis; 12 patients (22%) had mitral stenosis and pure aortic regurgitation; 8 patients (15%) had pure regurgitation of both valves; and 4 patients (7%) had pure aortic regurgitation and mitral stenosis. Necropsy examination in the 54 patients disclosed a high frequency (48%) of anatomic evidence of interference to poppet or disc movement in either the mitral or aortic valve position or both. Anatomic evidence of interference to movement of a poppet or disc in the aortic valve position was twice as common as anatomic evidence of interference to poppet or disc movement in the mitral position. Interference to poppet movement is attributable to the prosthesis's being too large for the ascending aorta or left ventricular cavity in which it resided. The ascending aorta is infrequently enlarged in patients with combined mitral and aortic valve dysfunction irrespective of whether the aortic valve is stenotic or purely regurgitant. Likewise, the left ventricular cavity is usually not dilated in patients with combined mitral and aortic valve stenosis, the most common indication for replacement of both left-sided cardiac valves. Of the 54 patients, 12 (22%) had 1 mechanical and 1 bioprosthesis inserted. It is recommended that both substitute valves should be mechanical prostheses or both should be bioprostheses.

Thrombotic obstruction of Bjork-Shiley valves--diagnostic and surgical considerations

We have evaluated 12 patients with thrombotic obstruction of the Bjork-Shiley valve since 1975, 11 in the mitral and 1 in the aortic position. During this period 442 patients with 303 mitral (181 plano-convex and 122 convexo-concave) and 205 aortic (112 plano-convex and 93 convexo-concave) Bjork-Shiley valves were available for follow-up. The incidence of thrombosis for the plano-convex model was 1.06% per patient year for the mitral position and 0.19% per patient year for the aortic position. The new convexo-concave model has brought down the incidence to 0.78% per patient year for the mitral (P less than 0.01) and 0% per patient year for the aortic valve. The onset of symptoms was acute (less than 15 days) in 41.7% and subacute (greater than 15 days) in 58.3% patients. All patients presented with pulmonary edema. Evidence of inadequate anticoagulation was present in only 3 (25%) patients. Reduction of prosthetic sounds and appearance of a new murmur was highly suggestive of valve thrombosis. Echocardiography and cinefluoroscopy was very useful for the instant recognition of this condition and had obviated the need for cardiac catheterisation in the last 6 patients. Emergency surgery was obligatory in all. Thrombectomy alone was successful in 9 patients. Three patients required replacement of the prosthesis. There was one operative death (mortality 8.3%). The long-term follow-up of these patients (3-82 months, mean 34 months) is excellent. We conclude that thrombotic obstruction of the Bjork-Shiley valve is often not related to inadequate anticoagulation, and more than half of the patients do not present with abrupt onset of symptoms. The convexo-concave model has significantly reduced this problem. Emergency surgery with thrombectomy is the procedure of choice for clotted prostheses.

Early results of valve replacement with the Björk-Shiley convexoconcave prosthesis

The Björk-Shiley convexoconcave prosthetic valve has design characteristics that may result in a lower incidence of thromboembolic complications than the conventional spherical Björk-Shiley prosthesis. We evaluated the results of valve replacement with the convexoconcave prosthesis in 248 patients receiving 301 prosthetic valves between March, 1979, and June, 1981. One hundred thirteen patients had aortic valve replacement (AVR), 73 had mitral valve replacement (MVR), and 62 had multiple valve replacement. Two hundred nine (84%) were in New York Heart Association Class III or IV. The median duration of follow-up was 13 months, and follow-up information was available for 246 (99%) of the patients. The actuarial incidence of freedom from thromboembolism at two years was 98% in the AVR group, 97% in the MVR group, and 87% in the group having multiple valve replacement. There were no documented episodes of valve thrombosis or mechanical failure and no fatal thromboembolic complications. The absence of valve thrombosis is in marked contrast to the results reported with the spherical disc valve. Although longer follow-up is necessary, it appears that the convexoconcave design represents a major improvement in the Björk-Shiley prosthesis.

Early results after combined aortic and mitral valve replacement with the convexo-concave Björk-Shiley prosthesis

This paper reports the early results of combined aortic and mitral valve replacement in 39 patients, who underwent operation with the convexo-concave Björk-Shiley prosthesis. There were no intra-operative deaths. Two patients (5%) died while in hospital of myocardial failure and left ventricular rupture, respectively. One late death (3%) was due to a thrombosis of the mitral prosthesis (N.Y.H.A. class IV at operation). Cumulative follow-up (2-31 months) was 100%. One patient had radial artery embolization while converting to atrial fibrillation. Another patient required repair of an aortic paraprosthetic leakage. Clinical improvement (N.Y.H.A.) was noted in 15/19 re-examined patients (79%). Average heart volume decreased (p less than 0.05) and Maximal working capacity increased (p less than 0.05) after valve replacement. Seven patients (7/19) converted to sinus rhythm after operations and one (1/19) developed atrial arrhythmia. Haemolysis was generally mild and without signs of anaemia. The overall thrombo-embolic rate (5.9% per year) remained thus far the same as that encountered with the standard model prosthesis in combined aortic and mitral valvular disease.

Multiple valve replacement with pericardial xenograft. Clinical and haemodynamic study

Multiple valve replacement with pericardial xenografts (sizes 17 to 31) was undertaken in 76 patients. The incidence of early and late deaths was 10.5 and 3.9 per cent, respectively. ACtuarially it is predicted that 94.7 +/- 3.9 per cent of hospital survivors will be alive at three and a half years after valve replacement. Though long-term anticoagulants were not used, thrombotic valve obstruction was not seen in this series. A systemic embolus occurred early in one case only (0.95 episodes/100 patient years). Mechanical dysfunction of the pericardial xenograft has not been seen. Haemodynamic studies were performed in seven patients, eight to 21 months after valve replacement. The transvalvular gradients were negligible across the aortic pericardial xenografts. Gradients across mitral and tricuspid xenografts were small. The calculated surface areas ranged from 1.0 to 1.4 cm2 for aortic, 1.7 to 2.1 cm2 for mitral, and 2.0 to 2.4 cm2 for tricuspid valves. These results after multiple valve replacement are comparable to those reported with isolated mitral or aortic pericardial xenografts over a similar period of observation.

Central haemodynamics at rest and during exercise before and after combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis

Pre- and postoperative haemodynamics were compared in 36 patients with combined aortic and mitral valvular disease. These patients suffered from markedly restricted cardiac function in terms of cardiomegaly, low physical working capacity, hypokinetic central circulation and pulmonary hypertension. Valve replacement was performed with the Björk-Shiley Delrin disc (10) and pyrolytic carbon disc (26) prostheses and followed by subjective improvement in the majority of patients. Heart volume decreased and working capacity increased in average significantly, but were not restored to normal. The main response to surgery was a shift towards a normokinetic circulation, although many patients remained hypokinetic. There was also regression of pulmonary hypertension as a result of reduced left atrial pressure and pulmonary vascular resistance. In spite of a significant decrease in left atrial mean pressure, it remained elevated with prominent v-waves in many patients, particularly during exercise. Marked v-waves in the right atrial pressure curves were also noted in one third of the patients. Only one patient, however, suffered from clinically manifested tricuspid incompetence. This study shows the benefits of combined aortic and mitral valve replacement, even in patients with longterm haemodynamic burden on the myocardium. Although the central haemodynamics were almost normalized at rest, abnormal responses persisted during exercise.

Clinical and hemodynamic results after combined aortic and mitral valve replacement with the Lillehei-Kaster pivoting disc valve

Combined mitral and aortic valve replacement with the Lillehei-Kaster pivoting disc valve prosthesis was performed in 23 patients. Hospital mortality rate was 8.3 per cent. Detailed postoperative clinical and hemodynamic studies were performed after a mean follow-up period of 24.4 months. Replacement of both valves had resulted in a marked symptomatic and hemodynamic improvement with a normal or nearly normal resting value of cardiac output, pulmonary arterial pressure, and pulmonary vascular resistance while left ventricular end-diastolic pressure (LVEDP) had increased significantly. The rise in left ventricular end-diastolic pressure most probably might be related to the simultaneous rise in cardiac output (Starling mechanism), reflecting the severity and irreversibility of the underlying myocardial disease. Most patients also had systolic gradient across the aortic prosthesis, as well as diastolic gradient across the mitral prosthesis. The gradients across the mitral prosthesis were approximately the same as seen after single valve replacement, while the pressure gradients across the aortic prosthesis were somewhat smaller than previously reported. Angiographic studies of the aortic valve movement indicated that the opening angle of the disc was approximately 60 degrees, and thus less than according to the valve specifications.

Combined multiple-valve procedures: a five-year experience with 125 patients

One hundred twenty-five patients underwent 128 operations for combined multiple-valve procedures, with an overall early mortality of 16%. Highest mortality was associated with mitral and tricuspid valve disease (28.5%), followed by triple-valve disease (18.2%) and aortic and mitral valve disease (14%). Left ventricular end-diastolic pressure, cardiac index, mean pulmonary artery pressure, pulmonary artery wedge pressure, and arteriovenous oxygen difference were all significantly different in patients with regard to early mortality. Late follow-up of 94% has been achieved in 105 early survivors, with a late mortality rate of 11.2%. Analysis of late functional results reveal that 85% of survivors improved at least one Functional Class. Actuarial 5-year survival of 75% was achieved for early survivors of operation.

Clinical and haemodynamic observations after combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis. Early and late results in 25 patients

Combined mitral and aortic valve replacement with the Björk-Shiley tilting disc valve (pyrolite) was performed in 25 unselected patients characterized by markedly impaired functional capacity, hypokinetic central circulation and cardiomegaly before operation. Surgery was performed during extracorporeal circulation with deep hypothermia. The mitral valve was replaced first in all cases. There were no intra-operative deaths, but 2 patients died while still in hospital (8.0%). One patient died 2 months postoperatively due to progressive heart failure. The remaining patients--with the exception of one who had died of cancer of the ovary--were re-examined in average 28.7 (18-40) months postoperatively. Most patients had improved symptomatically and were in functional classes I-II (N.Y.H.A.). The haemodynamic findings indicated restoration to normal resting values of cardiac output, pulmonary artery pressure and pulmonary vascular resistance, but with an increase in left ventricular end-diastolic pressure (LVEDP). The mean diastolic gradient across the mitral prosthesis varied from 0 to 11 mmHg, while simultaneous pressure recordings from the left ventricle and the aorta, with one exception, disclosed no systolic pressure gradients (peak) across the aortic valve. Postoperative arterial thrombo-embolic complications occurred in 2 patients, resulting in only minor neurological sequelae.