The low profile Ionescu-Shiley pericardial xenograft valve had been initially introduced to have improved hemodynamic performance and expected superior durability. However, subsequent clinical reports and laboratory studies have repeatedly
indicated
early failure of the valve from mechanical reasons in valve design.
A total and consecutive 169 patients underwent isolated MVR with the low profile Ionescu-Shiley valve at Seoul National University Hospital from November 1984 to October 1989 (Group ISLM). Five patients (3.0%) died within from November 1984 to
October
1989 (Group ISLM). Five patients (3.0%) died within 30 days of surgery, and early survivors were followed up for 734.9 patients-years (Mean±SD, 4.9±2.0 years). Late mortality rate was 0.136%/patient-year (pt-yr). Linearized incidences of major
complications were : 0.953% embolism/pt-yr ; 0.680% bleeding/pt-yr; 0.272% endocarditis/pt-yr ; and 0.408% primary tissue failure (PTF) /pt-yr. The actuarial survival was 99.4±4.6% and 95.9±2.4% at 8 years, respectively.
These results were compared with the clinical data from the 291 patients of isolated MVR with the standard Ionescu Shiley valve at the same hospital during the period between October 1978 and June 1983 (Group ISUM). Group ISUM included 11% of
patients
younger than 15 years of are, whereas Group ISLM did no patient of this age. The mean age at the time of surgery was significantly younger in group ISUM than one in Group ISLM (P<0.001). Differences were not statistically significant in operative
mortality, mean follow-up period and linearized incldences of thromboembolism, bleeding and endocarditis, between two groups. However, the linearzied rate of PTF was lower (P<0.001) and probabilities of freedom from PTF higher (P<0.001) in group
ISLM at
least up to postoperative 8 years.
While the features of PTF of the standard valve was predominantly degeneration with calcification and stenosis, the ones of the low profile valve was cusp tear and incompetence. It remains, however, to be seen whether the low profile valve fails
mostly
from mechanical reason, and further follow-up will still be necessary to determine the differences in mode of PTF of two valves.
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