Multi-layer haemocompatible diamond-like carbon coatings obtained by combined radio frequency plasma enhanced chemical vapor deposition and magnetron sputtering.

Radio-frequency Plasma Enhanced Chemical Vapour Deposition (in different methane dilutions) was used to synthesize adherent and haemocompatible diamond-like carbon (DLC) films on medical grade titanium substrates. The improvement of the adherence has been achieved by interposing a functional buffer layer with graded composition TixTiC1-x (x = 0-1) synthesized by magnetron co-sputtering. Bonding strength values of up to ~67 MPa have been measured by pull-out tests. Films with different sp(3)/sp(2) ratio have been obtained by changing the methane concentration in the deposition chamber. Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction were employed for the physical-chemical characterization of the samples. The highest concentration of sp(3)-C (~87 %), corresponding to a lower DLC surface energy (28.7 mJ/m(2) ), was deposited in a pure methane atmosphere. The biological response of the DLC films was assayed by a state-of-the-art biological analysis method (surface enhanced laser desorption/ionization-time of flight mass spectroscopy), in conjunction with other dedicated testing techniques: Western blot and partial thromboplastin time. The data support a cause-effect relationship between sp(3)-C content, surface energy and coagulation time, as well as between platelet-surface adherence properties and protein adsorption profiles.

Left atrial remodelling early after mitral valve repair for degenerative mitral regurgitation.

OBJECTIVE: Left atrial (LA) size is an important predictor of outcome after mitral valve replacement in patients with symptomatic chronic mitral regurgitation (MR). Data on LA remodelling after mitral valve repair (MVr) for chronic non-ischaemic MR are scarce. The aim of this study was to assess changes in LA size early after MVr for chronic severe degenerative MR and to identify clinical and echocardiographic correlates of those changes. METHODS: The study analysed 225 consecutive patients who underwent MVr and were echocardiographically evaluated in our hospital within 1 month before and 1-6 months after surgery. Patients with MR aetiology other than degenerative, associated aortic valve replacement, or congenital heart disease were excluded. The remaining 79 patients (aged 60 (SD 12) years, 55 men) with isolated chronic severe degenerative MR formed the study group. LA reverse remodelling was defined as a decrease in LA volume index (LAVi) > or = 15%. RESULTS: LA dimensions significantly decreased after MVr (p<0.001). Mean LAVi reduction was 29% (SD 18%). LA reverse remodelling was observed in 63 patients (80%). Correlates of LAVi reduction were preoperative LAVi (p = 0.008), systolic and diastolic blood pressure (p = 0.032, p = 0.009), postoperative transmitral mean pressure gradient (p = 0.001) and residual MR (p = 0.043). LAVi reduction was lower in patients > 45 years (p = 0.008) and in hypertensive patients (p = 0.031). CONCLUSION: LA reverse remodelling is common early after MVr for chronic severe degenerative MR. Preoperative LAVi, blood pressure, postoperative transmitral mean pressure gradient, residual MR and age > 45 are related to LAVi reduction. The prognostic value of LA reduction in this setting needs further study.