Heart Valve Diseases ; therapy ; Heart Valve Prosthesis Implantation ; methods ; Humans

Aged, 80 and over ; Heart Valve Prosthesis Implantation ; methods ; Humans ; Male ; Prosthesis Failure

Age-related degenerative calcification is currently the most common cause of aortic stenosis (AS) in adults and the most frequent reason for aortic valve replacement in patients with AS. With the increased life expectancy, a large proportion of elderly patients with AS is undergoing cardiac surgery, although many are not offered conventional aortic valve replacement due to the risks involved. However, sutureless aortic valve replacement provides an alternative for this group of elderly patients. This case series reports the first experience in Asia of sutureless aortic valve implantation in seven patients at our institution.
Aortic Valve Stenosis ; epidemiology ; surgery ; Asia ; epidemiology ; Heart Valve Prosthesis ; Heart Valve Prosthesis Implantation ; methods ; Humans

Aortic Valve Stenosis ; surgery ; Heart Valve Prosthesis ; Heart Valve Prosthesis Implantation ; methods ; trends ; Humans

OBJECTIVETo explore a new approach to the management of malignant biliary obstruction using percutaneous transhepatic biliary radiofrequency and endoprothesis.

METHODSPercutaneous transhepatic biliary radiofrequency and endoprothesis were performed in 2 cases of malignant biliary obstruction, including 1 of hilar cholangiocarcinoma and 1 of pancreatic head carcinoma. The tumor was ablated with radiofrequency followed by placement of matched metal stents into the biliary duct.

RESULTSThe surgical procedures were carried out smoothly in the 2 cases. The symptoms of the patients were obviously improved after the operation with a significant decrease in the serum levels of total bilirubin, and CA-199 level decreased to the normal level in 1 case.

CONCLUSIONSThis new approach is safe for management of malignant biliary obstruction. Compared with the more conventional interventional therapy, radiofrequency can reduce the intraoperative bleeding and arrest the local tumor growth to promote the patency of the stent as well as the postoperative survival of the patients.

Adult ; Aged ; Catheter Ablation ; methods ; Female ; Humans ; Jaundice, Obstructive ; etiology ; surgery ; Male ; Prosthesis Implantation ; methods ; Stents

Dental Implantation, Endosseous ; methods ; Dental Implants ; Dental Prosthesis, Implant-Supported ; methods ; Humans ; Surgery, Computer-Assisted

OBJECTIVETo evaluate the feasibility and short-term results of transcatheter aortic valve implantation (TAVI) using a new transcatheter valve.

METHODSTwenty healthy adult sheep received general anesthesia. Under the guidance of X-ray and transthoracic echocardiography (TTE), the new anti-calcification transcatheter valve was released from delivery system and implanted at the level of native aortic annulus via left common carotid artery. Position and function of the new anti-calcification transcatheter valve were evaluated by angiography and TTE immediately after intervention. Thirty day survival rate of animals was obtained.

RESULTSNew transcatheter valves were implanted in all sheep. Fifteen sheep (75%) survived up to 30 days and post-operative examination showed that the transcatheter valve was in optimal position without migration and mitral valve impingement. The native coronary artery was patent in these animals. There was a slight paravalvular leak in 5 sheep. Postoperative echocardiography showed reflux percentage was significantly increased (P < 0.05) compared pre-intervention. Effective orifice area, aortic systolic pressure, diastolic aortic pressure, mean aortic pressure, left ventricular systolic pressure, left ventricular end diastolic pressure and heart rate were similar between post and pre-intervention (all P < 0.05). Five sheep died after TAVI within 30 days, including one fatal ventricular fibrillation occurred immediately after releasing the transcatheter valve and another sheep died of acute myocardial infarction due to left main coronary artery occlusion evidenced by angiography. Two sheep died of severe mitral regurgitation at 8 and 12 hours post-operation and one died of infective endocarditis at 26 days after intervention.

CONCLUSIONOur favorable preliminary results showed that it was feasible to perform TAVI using the new transcatheter valve.

Animals ; Aortic Valve ; surgery ; Aortic Valve Stenosis ; surgery ; Heart Valve Prosthesis ; Heart Valve Prosthesis Implantation ; methods ; Sheep ; Treatment Outcome

Stent implantation can cause thrombus, vessel injury and blood flow disturbance which are considered as the main causes of instent restenosis. In order to investigate the influence of stent implantation on vessel wall and blood flow, we used finite element method (FEM) and computational fluid dynamics (CFD) in this work. The results showed that the implantation of the stent could cause vessel injury and flow stagnation. The instant recoil of the implanted stent is much more than that of the stent itself (12.3% versus 3.1%). In conclusion, FEM and CFD can help illustrate and quantify some biomechanical characteristics for the optimization of stent design.
Blood Flow Velocity ; physiology ; Computer Simulation ; Finite Element Analysis ; Humans ; Models, Cardiovascular ; Prosthesis Design ; Prosthesis Implantation ; methods ; Stents ; adverse effects

OBJECTIVEThe purpose of this study was to determine the feasibility of transcatheter pulmonary valve replacement in sheep up to 6 months post procedure.

METHODSFresh sheep pericardium treated with a 0.6% glutaraldehyde solution for 36 hours was sutured to a valvular ring and then fixed onto a newly designed nitinol self-expandable stent. Thoracotomy was performed in sheep (23.5 +/- 3.1) kg under general anesthesia and the device was delivered into the native pulmonary valve of the sheep via the anterior wall of right ventricle by catheter and fooled for 6 months.

RESULTSOne sheep died 4 months after the procedure due to in-stent thrombosis. Another 4 animals survived the 6-month observing period. Angiographic and hemodynamic measurements confirmed good positioning and function of the stents with a competent valve immediately post procedure and 6 months post the procedure in surviving animals.

CONCLUSIONImplantation of the nitinol self-expandable stent in the pulmonary valve position by a transcatheter approach is feasible and good function of transcatheter implanted memory nitinol valved stents was shown after 6 months of implantation in sheep.

Animals ; Disease Models, Animal ; Female ; Heart Valve Prosthesis ; Heart Valve Prosthesis Implantation ; instrumentation ; methods ; Male ; Pulmonary Valve ; surgery ; Sheep ; Stents

OBJECTIVETo compare the stress distribution of the staggered and straight placement of implants in the mandibular posterior region.

METHODSUsing three-dimensional finite element approach to analyze the stress distribution and variance regularity under the localized load.

RESULTSUnder vertical load, the stress peak value reduced when wide implant was placed straight (min: 3.70 MPa), but slightly increased when normal implant was placed staggered (max: 8.32 MPa); under the inclined load from buccal to lingual direction, the stress peak value reduced when the wide implant was placed in straight line (min: 12.29 MPa) or normal implant was placed staggered with buccal offset configuration (min: 15.48 MPa), but increased with lingual offset configuration (max: 23.60 MPa).

CONCLUSIONSWide implant (> or = 4 mm) with straight placement should be adopted to reduce the stress peak value and improve stress distribution, when the buccolingual diameter of the alveolar ridge in the mandibular posterior region was wide.

Adult ; Dental Implantation, Endosseous ; methods ; Dental Prosthesis Design ; Dental Prosthesis, Implant-Supported ; Dental Stress Analysis ; Finite Element Analysis ; Humans ; Mandible