One-year experience with the Edwards stentless "Prima" aortic bioprosthesis.

The aortic stentless bioprothesis are expected to have an improved hemodynamic function because of their lack of a sewing ring and stents. From April 1993 to March 1994 we implanted aortic Edwards "Prima" stentless bioprotheses in 21 patients suffering from aortic valve disease. In some patients additional cardiac procedures (CABG, MVR, tricuspid valve anuloplasty) were performed. The patients' age ranged from 56 to 78 years. The size of the bioprothesis ranged from 23 mm to 29 mm in diameter. We used either the subcoronary or the "mini-root" continuous suture technique. Aortic cross-clamp time ranged from 52 min to 128 min. There was no operative mortality. The intraoperative measurements showed that the pressure gradient across the aortic valve was very low or even undetectable. The echocardiographic control after 1 year revealed very good valve function. Our initial experience with this new valve shows a very good short-term result with an only slightly longer cross-clamp time. Since the valve has not been available for a long line, long-term results could not yet be observed.

Results of mitral valve reconstruction in mitral valve insufficiency.

In the last three years forty mitral valve reconstruction (MR) procedures were performed in case of mitral insufficiency (MI). In three cases, anatomical changes made reconstruction impossible for us. One patient had to be re-operated because of unsatisfactory valve function. There was no operative mortality. In twelve of the patients, mitral insufficiency was the only problem, while in twenty eight others additional cardiac procedures (CABG, AVR) were performed. The patients' age ranged from 17 to 77 years. The aortic cross-clamping time for mitral reconstruction without additional cardiac procedures ranged from 35 to 134 minutes. With one exception, the post-operative TEE indicated no, or very little, insufficiency. We concluded that the mitral valve insufficiency can be corrected with very good results and with a very low rate of complications. Such corrections ought therefore be taken into consideration before valve replacement.

Importance of blood viscoelasticity in arteriosclerosis.

Corpuscular and biochemical components of blood create the viscoelastic nature of blood flow, which varies because of changes in flow velocity. The flow properties of blood are of special interest in arteriosclerotic diseases for vasoregulatory mechanisms are often disturbed in these states. The authors compared the rheologic properties of blood in patients with arteriosclerotic lesions (coronary heart disease: n = 56; cerebrovascular disease: n = 37; peripheral arterial occlusive disease: n = 29 and healthy controls: n = 42). With a new oscillating capillary rheometer imitating the physiologic pulsations of blood flow in an unbranched artery, the viscosity (eta') and elasticity (eta") of whole blood and plasma were measured (diameter of the capillary: 0.9928 mm; pulse rate: 2/s; shear rate: gamma = 0.03-200/s; temperature: 37 degrees C). In arteriosclerotic patients a statistically significant elevation of the viscoelasticity of whole blood and plasma was found. In addition, plasma fibrinogen levels were augmented in the patients' groups. Clotting parameters (Quick, partial thromboplastin time, platelet count) and total serum protein levels were in the normal range in all patients investigated. In conclusion the question arises whether the increase of blood viscoelasticity is an additional risk factor for patients with arteriosclerotic disease or if it is just a consequence of the underlying disease. The authors' observations concerning blood viscoelasticity support the clinical importance of improving blood rheology by appropriate therapeutic measures.