An in vitro evaluation of the hydromechanical properties on transcatheter edge-to-edge repair / 中国介入心脏病学杂志

Objective To establish a method for testing isolated mitral valve in vitro and quantitatively evaluate the effect of transcatheter edge-to-edge repair technology(TEER)on functional mitral regurgitation(FMR)(non-A2-P2 regurgitation).Methods In this study,an FMR(non-A2-P2 regurgitation)model was developed by dilating the annulus orifice and displacing the papillary muscle in isolated porcine mitral valve.The hydrodynamics characteristics of 6 valves were tested by a pulsatile flow testing system under different physiological and pathological conditions before and after TEER.Results The results show that the valve regurgitation improved from moderate-severe[regurgitant fraction(60.2±17.5)％]to mild-moderate[regurgitant fraction(34.7±12.0)％]by repair(P＜0.001).The EOA[(3.8±1.6)cm2 vs.(2.2±0.5)cm2,P＜0.001]and the forward cross valve pressure difference[(1.8±1.3)mmHg vs.(3.8± 1.8)mmHg,P＜0.001],which characterize the forward flow performance of the valve,were compared before and after repair,and the differences were statistically significant.At the same time,the repair caused valve stenosis(the effective orifice area decreased by 40％and the positive differential pressure increased by 110％),but the valves was still within the normal physiological range,and no iatrogenic stenosis was caused.Conclusions It can be seen that TEER has an effect on FMR.This study provides validation and evaluation methods in vitro for expanding indications and improving TEER,and reference for developing standards of transcatheter valve repair testing in vitro.

Application of 99mTc-DTPA in evaluation of blood-brain barrier permeability in patients receiving whole brain irradiation / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the pattern of blood-brain barrier (BBB) permeability changes during whole brain radiotherapy (WBRT) for metastatic brain tumor.</p><p><b>METHODS</b>Twenty patients with metastatic brain tumors receiving WBRT by 6 MV X-ray underwent (99)mTc-DTPA brain SPECT before and during WBRT (20, 40 Gy) and at 2 weeks after the end of irradiation. A frame of transverse (99)mTc-DTPA brain SPECT image that best displayed the brain metastasis was chosen, and the regions of interest (ROI) were defined in the tumor foci (T), the contralateral normal brain tissue (N) and the background outside the soft tissues around the cranium (B). The radioactive counts of every ROI were measured and the ratios of the total counts (T/B and N/B) before and during WBRT (20 Gy, 40 Gy) and at 2 weeks after the irradiation were calculated.</p><p><b>RESULTS</b>The average T/B and N/B in the 20 patients with 30 brain metastases was 142.2-/+51.1 and 82.6-/+42.3 before WBRT, 260.3-/+121.5 and 150.7-/+72.5 during 20 Gy WBRT, 251.6-/+118.3 and 161.8-/+68.4 during 40 Gy WBRT, and 250.3-/+117.2 and 158.6-/+73.5 at 2 weeks after the irradiation, respectively. The measurements during WBRT (20 and 40 Gy) and at 2 weeks after the irradiation group underwent no significant variations (P>0.05), but showed significant differences from those before WBRT (P<0.05).</p><p><b>CONCLUSIONS</b>Irradiation causes direct damage of the BBB function, and the permeability of the BBB increases significantly during and within 2 weeks following 20 and 40 Gy WBRT, which provides the optimal time window for interventions with chemotherapy.</p>

Analysis of the risk factors of acute renal insufficiency following coronary artery bypass grafting / 中华外科杂志

<p><b>OBJECTIVE</b>To study the risk factors of acute renal insufficiency (ARI) following coronary artery bypass grafting (CABG).</p><p><b>METHODS</b>The clinic data of 2242 patients undertaking CABG between July 1997 and July 2006 were retrospectively analyzed, and ARI following CABG was included.</p><p><b>RESULTS</b>ARI occurred in 219 patients, with an incidence of 9.8%. Univariate analysis revealed that advanced age, diabetes mellitus, preoperative chronic renal dysfunction, left main disease, low left ventricular erection faction, emergency operation, on-pump CABG, ascending aortic atherosclerosis, postoperative respiratory function insufficiency and low cardiac output syndrome were significantly related to ARI following CABG, and logistic multivariate regression analysis showed that presence of advanced age (P = 0.031), preoperatively chronic renal dysfunction (CrCl <or= 60 ml/min, P = 0.023 or Scr >or= 150 micromol/L, P = 0.041), on-pump CABG (P < 0.001), postoperative respiratory function insufficiency (P = 0.013) and low cardiac output syndrome (P = 0.004) were independent risk factors of ARI.</p><p><b>CONCLUSIONS</b>Advanced age, preoperatively chronic renal dysfunction, on-pump CABG, postoperative respiratory function insufficiency and low cardiac output syndrome are the risk factors of ARI following CABG.</p>