The CryoLife O'Brien stentless porcine aortic bioprosthesis: 5-year follow-up.

BACKGROUND: Mortality, morbidity, complication rates, and echo hemodynamic results using the Cryolife O'Brien stentless aortic bioprosthesis over a 5-year period are reported. METHODS: The stentless valve was implanted in 97 conscecutive patients, 54 male and 43 female, mean age 70.9 +/- 6.5 years. All patients underwent preoperative, discharge (early study), 6-month (intermediate study), and late (18.3 +/- 10.4 months) echocardiography. RESULTS: The actuarial 5-year survival rate was 93.9% +/- 3%. Aortic regurgitation was absent in 95.5%, mild in 3.4%, and moderate in 1.1%. Peak and mean systolic gradients were significantly lower at discharge (p < 0.001) and at the 6-month follow-up (p < 0.001) but did not significantly fall further at the late study (p = NS). The effective orifice area index at discharge (p < 0.001) and at 6 months (p < 0.001) differed significantly from preoperative values, but variations at late study were not significant (p = NS). Left ventricular mass index decreased early postoperatively (p < 0.001) and at 6-month assessment (p < 0.001) with a further significant reduction at late echocardiography (p = 0.04). CONCLUSIONS: The 5-year results of this stentless valve showed a low rate of valve-related complications with excellent hemodynamic performance in all valve sizes.

Immunoquantification of total apolipoprotein B in serum by nephelometry: influence of lipase treatment and detergents.

The immunoquantification of total apolipoprotein B in human serum has been evaluated by rate and equilibrium nephelometry. The presence of triglyceride-rich lipoproteins spoiled all immunochemical assays and yielded too-high values for apolipoprotein B. The use of detergents improved the results substantially, but results were inaccurate at high triglyceride concentrations. Of many detergents investigated, only Thesit, Kryo Ebo, and Apovax were useful, decreasing the light-scatter signals almost linearly with increasing detergent concentrations. The regression lines, however, were not parallel among the different apo B-containing lipoproteins. Incubating sera or apo B-containing lipoproteins with bovine milk lipoprotein lipase or bacterial triacylglycerol lipase, at concentrations of 100 kU/L, hydrolyzed all of the triglycerides and most of the phosphatidylcholine within 18 h at 37 degrees C Lipase-pretreatment of samples gave optimal correlation between apo B values as determined by nephelometry with those obtained gravimetrically. We also assessed the influence of sample storage, freezing, and thawing on the nephelometric apo B assays.