Evidence that apolipoprotein(a) phenotype is a risk factor for coronary artery disease in men < 55 years of age.

Whereas the importance of plasma lipoprotein(a) [Lp(a)] levels as a risk factor for premature coronary artery disease (CAD) is certain, it is not clear if the apolipoprotein(a) [apo(a)] phenotype plays an additional and independent role. To investigate the possible effect of apo(a) phenotype on premature CAD (in patients < 55 years of age), plasma Lp(a) concentrations, the apo(a) phenotypes, and their relation with many recognized CAD risk factors were examined in 96 non-diabetic male patients with angiographically defined CAD and in 83 age-matched male control subjects with no angiographic evidence of CAD. Results demonstrate that patients with premature CAD are characterized by higher Lp(a) levels (24 +/- 21 vs 17 +/- 15 mg/dl, p < 0.01) and a higher frequency of S2 phenotype (32% vs 15%, p < 0.01). Patients with an S2 phenotype exhibited significantly higher plasma Lp(a) concentrations than control subjects with the same isoform (37 +/- 22 vs 22 +/- 17 mg/dl, p < 0.05). A significant correlation was found between apo B and Lp(a) levels in patients with an S2 phenotype. In addition, patients had a low frequency of S1 and S4, and a high frequency of double-band phenotypes of apo(a). Multivariate analysis did not demonstrate an independent role for apo(a) phenotype as a risk factor for premature CAD. In conclusion, CAD patients < 55 years of age have a very different pattern of apo(a) phenotypes than subjects with no angiographic evidence of CAD; this study confirms the hypothesis that apo(a) phenotype may play an additional role in the etiology of premature CAD.

Rest and exercise hemodynamics of stentless porcine bioprostheses in aortic position.

Mechanical and conventional stented bioprostheses, because of need for anticoagulants, hemodynamic characteristics and long-term durability, do not represent the optimal heart valve replacement device. In this study we compared the hemodynamic function of a stented aortic bioprosthesis (St Jude Bioimplant), implanted in 10 patients, with a stentless porcine aortic bioprosthesis (Biocor) implanted in 7 patients, by means of Doppler echocardiography early postoperative at rest (T1) and 6 months later at rest (T2a) and during exercise (T2b). Mean and peak systolic gradients across stentless porcine prostheses were significantly lower than across stented bioprostheses (T1 p = 0.008 and p = 0.004; T2a p < 0.0001 and p < 0.0001; T2b p < 0.0001 and p < 0.0001, respectively). Our results show that systolic and diastolic mechanical stress on biological components of a glutaraldehyde-fixed stentless porcine aortic bioprosthesis is much lesser than on stented bioprostheses. This feature has appeared evident at rest and much more after exercise testing. The reduction of systolic and diastolic stress is expected to determine lower calcification degree and longer durability of stentless porcine aortic bioprostheses. Moreover, aortic valve replacement by means of stentless bioprostheses allows the implantation of a 1 size (2 mm) larger device, appearing favourable especially in small aortic annulus. On the basis of these promising results we suggest that stentless bioprostheses are a valid alternative to stented bioprostheses for aortic valve replacement. However, patient population is too small and the follow-up is too short to draw a definite statement about long-term hemodynamic performance of this device.