OBJECTIVETo evaluate the feasibility and effectiveness of transcatheter transapical implantation of a new domestic balloon-expandable bioprosthetic aortic valve in goats.

METHODSWe developed a new tube-like balloon-expandable bioprosthetic aortic valve which was made from cobalt-chromium alloy and bovine pericardium. Briefly, fresh bovine pericardium was trimmed into artificial leaflets and sutured into the cobalt-chromium alloy stent by hand post cell extracting and anti-calcification treatments. A left anterolateral mini-thoracotomy was performed in the 5(th) intercostal space of 5 goats. After opening the pericardium, the apex of the left ventricle was punctured, a stiff guidewire was positioned across the aortic arch and anchored in the descending aorta. The delivery catheter (22 F) was then introduced through the stiff guidewire into the aorta arch under fluoroscopic guidance. After correct valve position was confirmed by digital subtraction angiography, the valved stent was implanted after rapid inflation of the balloon. The immediate results of implanted valved stents were evaluated with angiography and echocardiography.

RESULTSFour devices were successfully implanted into aortic valve position of goats and one goat died of severe aortic valve regurgitation because the valved stent was implanted below the normal position.Immediate observation after procedure in 4 goats by angiography and echocardiography showed that the valved stents were in the desired position after implantation. Mild paravalvular leakage were found in 3 out of the 4 survived goats and there were no moderate to severe aortic regurgitation in survived goats.

CONCLUSIONThe procedure of transcatheter transapic aortic valve implantation with our new-type domestic balloon-expandable valved stent and delivery system is feasible and effective.

Animals ; Aortic Valve ; Catheterization ; Cattle ; Female ; Goats ; Heart Valve Prosthesis Implantation ; instrumentation ; methods ; Male ; Stents

Objective:To prepare a 68Ga labeled probe targeting integrin alpha M(CD11b) receptor, namely 68Ga-1, 4, 7-triazacyclononane-1, 4, 7-triacetic acid-Glycine-Arginine-Glutamate-Arginine-Glutamate-polyethylene glycol 11-1, 2, 4, 5-terazine/CD11b antibody-F(ab′) 2-trans-cyclooctene ( 68Ga-NOTA-Polypeptide-PEG 11-Tz/anti-CD11b-F(ab′) 2-TCO), and to explore its feasibility as a molecular probe for CD11b receptor through microPET imaging. Methods:Immunofluorescence was used to detect the expression of CD11b on the surface of RAW264.7 cell. CD11b specific monoclonal antibody (M1/70) was conjugated with TCO, and anti-CD11b-F(ab′) 2-TCO fragment was obtained. The ligand NOTA-Polypeptide-PEG 11-Tz was labeled with 68Ga, and its specific activity and radiochemical purity were detected. Pre-targeted cell binding experiment was conducted to evaluate the binding ability of molecular probe. CT26 colon cancer bearing mouse models were established, and then pre-targeted biodistribution and imaging experiments were performed. Immunohistochemical experiment was used to verify the expression of CD11b receptor in tumor. The one-way analysis of variance was used to compare the data. Results:The results of immunofluorescence demonstrated CD11b receptor was highly expressed on the surface of RAW264.7 cell. Anti-CD11b-F(ab′) 2-TCO fragment was verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). 68Ga-NOTA-Polypeptide-PEG 11-Tz was successfully synthesized, with the labeling efficiency of 94.6%. The specific activity was 7.0-7.4 MBq/μg, and the radiochemical purity was higher than 95%. Pre-targeted cell binding experiment confirmed that the molecular probe bound to the CD11b receptor. The biodistribution and imaging experiments showed that the kidney radioactivity uptake was high at pre-targeted 4, 12 and 24 h intervals, which proved that probe was excreted through the urinary system. In addition, molecular probe had higher radioactive uptake at the tumor site, with the tumor/muscle ratios of 9.23±1.45, 12.53±1.36 and 10.74±1.11 ( F=848.8, P<0.05). When the radioligand was injected 1 h after the pre-positioned 12 h interval, the images contrast was the best, with the standardized uptake value (SUV) in tumor and muscle of 0.67±0.12, 0.09±0.04, respectively. Immunohistochemistry verified the highly expression of CD11b receptor in tumor. Conclusions:The pre-targeted molecular probe 68Ga-NOTA-Polypeptide-PEG 11-Tz/anti-CD11b-F(ab′) 2-TCO is successfully synthesized. The molecular probe has targeting ability for CD11b + colon cancer, and is expected to be used as a tracer targeting CD11b receptor in vivo.