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.

Insights into the interstitium of ventricular myocardium: interstitial Cajal-like cells (ICLC).

We have previously described interstitial Cajal-like cells (ICLC) in human atrial myocardium. Several complementary approaches were used to verify the existence of ICLC in the interstitium of rat or human ventricular myocardium: primary cell cultures, vital stainings (e.g.: methylene blue), traditional stainings (including silver impregnation), phase contrast and non-conventional light microscopy (Epon-embedded semithin sections), transmission electron microscopy (TEM) (serial ultrathin sections), stereology, immunohistochemistry (IHC) and immunofluorescence (IF) with molecular probes. Cardiomyocytes occupy about 75% of rat ventricular myocardium volume. ICLC represent approximately 32% of the number of interstitial cells and the ratio cardiomyocytes/ICLC is about 70/1. In the interstitium, ICLC establish close contacts with nerve fibers, myocytes, blood capillaries and with immunoreactive cells (stromal synapses). ICLC show characteristic cytoplasmic processes, frequently two or three, which are very long (tens up to hundreds of microm), very thin (0.1-0.5 microm thick), with uneven caliber, having dilations, resulting in a moniliform aspect. Gap junctions between such processes can be found. Usually, the dilations are occupied by mitochondria (as revealed by Janus green B and MitoTracker Green FM) and elements of endoplasmic reticulum. Characteristically, some prolongations are flat, with a veil-like appearance, forming a labyrinthic system. ICLC display caveolae (about 1 caveola/ 1 microm cell membrane length, or 2-4% of the relative cytoplasmic volume). Mitochondria and endoplasmic reticulum (rough and smooth) occupy 5-10% and 1-2% of cytoplasmic volume, respectively. IHC revealed positive staining for CD34, EGFR and vimentin and, only in a few cases for CD117. IHC was negative for: desmin, CD57, tau, chymase, tryptase and CD13. IF showed that ventricular ICLC expressed connexin 43. We may speculate that possible ICLC roles might be: intercellular signaling (neurons, myocytes, capillaries etc.) and/or chemomechanical sensors. For pathology, it seems attractive to think that ICLC might participate in the process of cardiac repair/remodeling, arrhythmogenesis and, eventually, sudden death.

Right ventricular functional recovery after acute myocardial infarction: relation with left ventricular function and interventricular septum motion. GISSI-3 echo substudy.

OBJECTIVE: To evaluate the pattern of right ventricular (RV) functional recovery and its relation with left ventricular (LV) function and interventricular septal (IVS) motion in low risk patients after acute myocardial infarction (AMI). DESIGN AND SETTING: Multicentre clinical trial carried out in 47 Italian coronary care units. PATIENTS: 500 patients from the GISSI (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico) -3 echo substudy, who underwent serial echocardiograms 24-48 hours after symptom onset and at discharge, six weeks, and six months after AMI. RESULTS: Tricuspid annular plane systolic excursion (TAPSE) increased significantly during follow up (mean (SD) 1.79 (0.46) cm at 24-48 hours to 1.92 (0.46) cm at six months, p < 0.001) and the increase was already significant at discharge (1.88 (0.47) cm, p < 0.001). LV ejection fraction (LVEF) was the best correlate of TAPSE at 24-48 hours (r = 0.15, p = 0.001). TAPSE increased significantly in patients both with reduced (< 45%) and with preserved (> or = 45%) LVEF, but the magnitude of increase was higher in patients with lower initial LVEF (p = 0.001). Improvement in IVS wall motion score index (IVS-WMSI) was the only independent predictor of TAPSE changes during follow up (r = -0.12, p = 0.007). CONCLUSIONS: In low risk patients after AMI, RV function recovered throughout six months of follow up and was already significant at discharge. TAPSE was significantly related to LVEF at 24-48 hours. The magnitude of RV functional recovery was higher in patients with lower initial LVEF. RV functional recovery is best related to IVS-WMSI improvement, suggesting that IVS motion has an important role in RV functional improvement in this setting.

Blind removal of lens distortion.

Virtually all imaging devices introduce some amount of geometric lens distortion. A technique is presented for blindly removing these distortions in the absence of any calibration information or explicit knowledge of the imaging device. The basic approach exploits the fact that lens distortion introduces specific higher-order correlations in the frequency domain. These correlations can be detected by using tools from polyspectral analysis. The amount of distortion is then estimated by minimizing these correlations.

Noninvasive assessment of left ventricular end-diastolic pressure by the response of the transmitral a-wave velocity to a standardized Valsalva maneuver.

Impaired relaxation is frequently masked by elevated filling pressures, resulting in a pseudonormal flow pattern (E/A >1.0). Because the E/A wave ratio increases as filling pressures rise, it is generally assumed that patients with an E/A ratio of <1.0 (impaired relaxation pattern) have relatively low filling pressures. Nevertheless, patients with an E/A ratio of <1.0 can have as profoundly elevated filling pressures as patients with a pseudonormal or restrictive filling pattern. Because left ventricular (LV) pressure during end-diastole essentially determines atrial afterload, the response of the A-wave velocity to a reduction of atrial afterload by a standardized Valsalva maneuver should allow estimation of LV end-diastolic pressure (LVEDP) regardless of the baseline Doppler flow pattern. This was tested in 20 consecutive patients who were studied by pulse-wave Doppler echocardiography during cardiac catheterization. There was a close correlation between LVEDP and the change in A-wave velocity during the Valsalva maneuver (r = 0.85, SEE 6.7 mm Hg) regardless of the baseline E/A ratio. In patients with a LVEDP of <15 mm Hg the A wave decreased by 21 +/- 15 cm/s. In patients with a LVEDP of >25 mm Hg the A wave increased by 18 +/- 13 cm/s. The change in the E/A ratio during Valsalva correlated fairly with LVEDP (r = -0.72, SEE 8.8 mm Hg), the baseline E/A ratio correlated poorly, and scatter was substantial (r = 0.46, SEE 11.2 mm Hg). Just as elevated filling pressures can mask impaired relaxation, the impaired relaxation pattern can mask the presence of elevated filling pressures. This can be revealed by testing the response of the A wave to the Valsalva maneuver, allowing estimation of LVEDP independent of the baseline E/A ratio.

Assessment of pseudohypertrophy as a measure of left-ventricular compression in patients with cardiac tamponade.

BACKGROUND: Left-ventricular pseudohypertrophy reflecting left-ventricular compression was reported in a selected group of patients with cardiac tamponade. HYPOTHESIS: Criteria for the presence of pseudohypertrophy can be established to guide its use as a sign of left-ventricular compression in patients with cardiac tamponade. METHODS: Left-ventricular wall thickness, diameters, relative diastolic wall thickness (%) = (posterior wall thickness/end diastolic radius) x 100 and estimated left-ventricular mass were measured in patients with small, moderate and large pericardial effusion, in patients with cardiac tamponade before and after pericardiocentesis (16 patients in each group) and in 30 control subjects with normal echocardiograms. RESULTS: Left-ventricular posterior wall thickness was increased (12 +/- 2 vs. 9 +/- 1 mm, p < 0.001), left-ventricular end-diastolic diameter was reduced (3.9 +/- 0.5 vs. 4.6 +/- 0.3 cm, p < 0.001) and relative left-ventricular diastolic wall thickness was increased (61 +/- 13 vs. 41 +/- 4.5%, p < 0.001) only in patients with cardiac tamponade compared to controls, but not in patients with small, moderate and large effusions, respectively (relative wall thickness: 42 +/- 5, 41 +/- 7 and 44 +/- 7%, p = NS). Mean values of the estimated left-ventricular mass were similar in all groups. Following pericardiocentesis all parameters were normal. CONCLUSIONS: Despite normal left-ventricular mass, relative left-ventricular diastolic wall thickness is elevated in patients with cardiac tamponade. In contrast it is normal in patients with various degrees of pericardial effusion supporting its use as a quantitative measure of left-ventricular compression in patients with suspected cardiac tamponade.