| Part?.Study of the Aortic Root in Aortic Stenosis in Chinese: Implications for Transcatheter Aortic Valve ReplacementBackground and purpose: With the development of transcatheter aortic valve implantation (TAVI), detailed knowledge of aortic root geometry is a prerequisite to improve on aortic valve stent and anticipate complications of TAVI. We determined coronary ostial locations and aortic root dimensions in patients with aortic stenosis (AS) and compared these values with normal. Dimensions of the aortic root and LVOT were compared with cardiac dual source CT (DSCT) and transthoratic echocardiography (TTE).Materials and Methods: 34 patients with AS and 39 patients without valvular pathology (referred to as the controls) undergoing DSCT and TTE were included. With DSCT the distances from the aortic annulus (AA) to the left coronary ostium (LCO), right coronary ostium (RCO), the height of the left coronary sinus (HLS), right coronary sinus (HRS), and diameters of AA, sinus of Valsalva (SV), and sino-tubular junction (STJ), ascending aorta (AO), left ventricular outer tract (LVOT), the aorto-mitral fibrous continuity (CF), interventricular septum (IVS) were measured. With TTE the diameters of aortic root and LVOT were measured and compared with DSCT.Results: LCO and RCO were 15.1±2.6 mm (9.1-21.2) and 15.8±3.3mm (9.4-25.4) in patients with AS, 15.6±2.0 mm (11.9-20.9) and 16.5±2.3mm (11.2-20.9) in the controls. Controls and patients with AS had similar values for LCO, RCO, HLS and HRS.AA,SV,STJ,AO were 25.8±3.5mm,35.4±5.3mm,30.6±5.0mm and 36.5±5.2mm in patients with AS, 23.3±2.3mm,35.1±3.9mm,27.9±3.3mm and 30.7±3.2mm in the controls . Patients with AS had significantly larger AA , STJ and AO diameters when compared with the controls(p<0.01).But in patients with AS, SV were similar to the controls(p>0.05).LVOT?IVS?CF were 27.6±4.8mm,12.9±2.5mm,15.2±2.1mm in patients with AS, 25.1±3.2mm,10.5±1.4mm,12.1±1.5mm in the controls. Patients with AS had significantly larger LVOT , IVS and CF diameters when compared with the controls(p<0.01).In patients with AS, AA,SV,STJ,AO,IVS diameters of end-systole were significantly larger than end-diastole(p<0.01), and LVOT diameters of end-systole were significantly smaller than end-diastole(p<0.05)In the controls, AA,SV,STJ,IVS diameters of end-systole were significantly larger than end-diastole(p<0.01),and LVOT diameters of end-systole were significantly smaller than end-diastole(p<0.01).A significant correlation was observed between methods of DSCT and TTE in dimensions of AA (r=0.84, p<0.01), SV (r=0.87, p<0.01), STJ (r=0.82, p<0.01) and AO(r=0.82, p<0.01), Bland-Altman plot demonstrated a good intermodality agreement on AA, SV, STJ and AO between DSCT and TTE, but with a obvious overestimation of STJ by DSCT (+1.09mm).Conclusions: The DSCT can provide detailed information on aortic root geometry. The designment and selection of the size of aortic valve stent were accorded to the values of measurement with DSCT. Owing to the dilatation of the aortic root, the dilatation and changing longer of the LVOT, and the large distribution of ostial locations, CT is recommended before TAVI in each patient.Part?.Aortic Valves Stenosis and Regurgitation: Assessment with Dual Source Computed TomographyPurpose: To prospectively evaluate diagnostic accuracy of dual source CT (DSCT) for evaluation of arotic stenosis (AS) and arotic regurgitation (AR), with transthoracic echocardiography (TTE) as reference.Materials and Methods: We evaluated a total of 79 patients who underwent both DSCT and TTE, 40 with aortic valve disease (33 patients with AS, 34 patients with AR, 27 patients with both AS and AR) as assessed by TTE and 39 matched controls. DSCT data sets were reconstructed in 10% steps from 0% to 90% of R-R interval for analysis. Maximum aortic valve area (AVA) in systole was planimetrically measured with DSCT, and measurements were compared with TTE,as well as maximum regurgitant orifice area (ROA) in diastole. Dimensions of the aortic root and left ventricular parameters were compared. Results: DSCT correctly identified 30 patients with AS (sensitivity 91%, specificity 100%, positive predictive value [PPV] 100% , and negative predictive value [NPV] 94%) and 32 patients with AR (sensitivity 94%, specificity 98%, positive predictive value [PPV] 97%, and negative predictive value [NPV] 96%). A significant correlation was observed between CT planimetric size of arotic valves area and TTE (r = 0.79; p< 0.01). Bland-Altman plot demonstrated a good intermodality agreement between DSCT and TTE with a slight overestimation of aortic valve area (AVA) by DSCT (+0.18cm2). A significant correlation was observed between CT planimetric size of ROA (0.49 cm2±0.40) and TTE classification of mild, moderate and severe AR (r = 0.79; p< 0.01). With ROC(The receiver operating characterisitic curve)analysis, discrimination between degrees of AR with DSCT was high accurate when cutoff ROAs (0.21cm2 and 0.71cm2). A significant correlation was observed between methods in dimensions of aortic annulus (r=0.87, p<0.01), sinus of valsalva (r=0.91, p<0.01) and ascending aorta (r=0.92, p<0.01), end-systolic volume (r=0.82, p<0.01), end-diastolic volume (r=0.87, p<0.01) and ejection fraction (r=0.86, p<0.01).Conclusions: DSCT can provide a simultaneous and accurate evaluation of the AVA, ROA, LVEF and aortic root dimensions in patients with AS or AR, and DSCT can achieve an exhaustive and comprehensive preoperative assessment of patients with AS and AR.Part?.Transcatheter Aortic Valve Implantation with a Self Expanding Stent in Animal ExperimentsBackground and Purpose: Transcatheter aortic valve implantation is a promising strategy in the treatment of patients with severe aortic valves stenosis. And two kinds of valves have been implanted in selected patients worldwide. However, the clinical experience is still limited. We developed a self expanding stent and evaluated the feasibility and safety of transcatheter aortic valve implantation of the device in native aortic valve position in pigs.Methods: A self expanding stent, was made of nitinols stent and porcine pericardium vaves in its proximal part. It was implanted in seven pigs by means of 18 French catheter through the apex or the right common iliac artery under guidance of fluoroscopy. During stent deployment, the original aortic valves were pushed against the aortic wall by the self expanding force of the stent while the new valve was explanded. These pigs were followed up shortly after procedure with supra-aortic angiogram and left ventriculography.Results: The self expanding stents were implanted in five pigs through the apex , only one pig was succeeded, but it died next day because of blood loss. The self expanding stents were successfully implanted in two pigs through the right common iliac artery,there were no signs of malfunction of the implant, or of obstructions of the coronary ostia and mitral valves.Conclusion: Transcatheter aortic valve implantation with a self expanding stent in the beating heart is possible. Further studies are mandatory to assess safety and efficacy of this kind of valves stent in larger sample size and by longer followed-up period. |
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