The Mosaic (R) bioprosthesis at 5 years

The Mosaic(R) bioprosthesis is a stented porcine aortic valve, which combin es the zero pressure differential fixation technique (by applying equal pre ssure to the in- and outflow ends of the valve, the aortic root is pressuri zed to maximize the flow area while no pressure is exerted on the leaflets) and an anti-mineralization treatment with alpha amino oleic acid for impro ved tissue durability. The device is in clinical use since February 1994. T he purpose of this study was to collect intermediate term data of the Mosai c(R) bioprosthesis in the aortic position to evaluate its clinical and hemo dynamic function. From February 1994 to May 1999, 100 patients underwent aortic valve replace ment with the Mosaic(R) prosthesis at our department. There were 49 female patients, mean age at implant was 73.4 +/- 7.3 years (range 31 to 87). Conc omitant procedures were done in 40%. Preoperative and operative clinical da ta are shown in Tables 1 and 2. When assessing the size of the bioprosthesi s, it is important to use the original Mosaic(R) sizer. Because of the poss ibility of the so-called supra-x placement, the specific construction of th e sizer and the Mosaic(R) valve often allow the implantation of a 1-size la rger valve compared to the conventional supra-annular placement. By this a significant increase in the effective flow orifice is possible. This procee ding is depicted in Figure 1. All patients have been anticoagulated with ph enprocoumon at least for 3 months postoperatively, INR was aimed at 2.5 to 3.5. Patients have been followed up prospectively, within the initial hospi talization for valve replacement, 6 months postoperatively and at annual in tervals including an hematological check and transthoracic echocardiography . The mean follow-up was 2.7 years with a total followup of 273.7 patient y ears. The follow-up was 100% complete. After 5 years the mean systolic pressure gradient was 15.2 +/- 3.0 mm Hg fo r the 21-mm, 13.1 +/- 4.6 mm HZ, for the 23-mm, 10.0 +/- 3.1 mm Hg for the 25-mm valve size, the effective orifice area 1.6 +/- 0.3 cm(2) (21-mm), 1.9 +/- 0.3 cm(2) (23-mm) and 2.5 +/- 0.8 cm(2) (25-mm) (see Table 3). The fre edom from prosthesis-related event rates, calculated according to Kaplan-Mc ier, at 5 years were: 97.3 +/- 1.9% for permanent neurological, 99.0 +/- 1. 0% for transient neurological, 95.9 +/- 32% for thrombosed prosthesis, 95.6 +/- 2.2% for antithromboembolic related hemorrhage, 96.2 +/- 3.7% for stru ctural valve deterioration, 96.9 +/- 3.0% for non-structural dysfunction, 1 00% for endocarditis and 92.0 +/- 4.9% for explant (see Table 4). The total operative mortality (within 30 days) was 3.0%, the late postoperative mort ality was 4.4% per patient year and included a valve related mortality rate of 0.7%/patient year. In Figure 2 the survival function after aortic valve replacement is depicted, arranged in freedom from all deaths, from Mosaic( R)-related deaths and From Mosaic(R)-related plus sudden/unexplained deaths . Before: implantation of the Mosaic(R) bioprosthesis 95% of the patients w ere in NYHA Classes III and IV. whereas 6 months postoperatively 98% could be classified in NYHA Classes I and II (see Figure 3). In relation to other biological prostheses (Intact(R), Carpentier-Edwards P ericardial(R) and Porcine(R), Hancock Modified Orifice(R), Biocor(R), Frees tyle(R)) the Mosaic(R) bioprosthesis showed very satisfactory and predomina ntly better hemodynamic results than the compared stented valves and approa ched the performance of stentless prostheses. The freedom rates from prosth etic-related adverse events of the Mosaic(R) bioprosthesis were at least eq uivalent to the compared prostheses. However, the satisfactory freedom rate s, especially from structural valve deterioration, should be qualified by c onsidering the experience that most incidences appear from the 5th year on after implantation. The clinical and hemodynamic performance of the Mosaic(R) prosthesis has be en very satisfactory during the first 5 years after clinical introduction. Further data will be necessary to confirm long-term durability.