| Objective: To understand the echo and function changes in porcine chIonicischemic myocardium; To investigate the value of ultrasonic illtegrated backscanertissue characterization and Doppler tissue imaging (DTI) in detecting chronicischemic myocardium before and after gene transfer Method: 1. l0 normal pigs weredivided into two grouPs, grouP I for gene transfer and grouP II for control. 2. Aftergeneral anesthesia, an Aineroid constrictor was placed around the proximal leftcircumflex artery (LCX) of each open-chest pig. 4 weeks later grouP I was directlyilltfamyocardially adIninistrated Replication-deficient recombinam adenovirus codingfor the vascular endothelial groWth factors (Ad. VEGF), and grouP lI wasadministrated PBS. 4 weeks after vector administration, all animals were killed andHistological and Pathological investigation of their hearts was performed. 3. HP sonos5500 with S4 transducef, all of the machine settings of integrated backscatter were thesame. The calibrated average image intensity (%AII) and cyclic variation ofintegrated backscaller (CVIB) in basic state and dobutamine-stress state of normalmyocardium, chronic ischemic myocardium and ischemic myocardium after genetransfer (before and 2w 4W 6w and 8w after Ameroid constrictors were placed). Thentri the machine settings to DTI-mode, to study the sPectri of lateral-posterior wallof left ventricular paPillary muscle level short axis view (LVPM-SAM) and aPicalfour chamber view (AP-4CV). 4. Toshiba UIDM-8000A with S5 transducef, to studythe chronic ischemic myocardium befOre and after gene transfer by using colorM-mode and two-dimensiona1 DTI. ResuIt: 1. The integrated backscatter of normallateral-posterior myocardium in contfOl grouP changed during cardiac period, with thehighest at end diastolic and the lowest at end systolic. The %AII was 2.29 f 0.32, the4x=--x-wde-msox xxw-CVIB was 9.69t 2.22, and the CVIB of subendocardium was 2.6dB higher than thatof subepicardium (ll.23 t 2.65dB Vs 8.68 l l.87dB), the subendo-epicardicalgradient index (TGI) was 0.22f0.08. 2 weeks aller AIneroid constrictor placement,the %AII increased to 3.64f l .03dB (P<0.0l), the CVIB decreased to 7. 1l I l .89dB(P<0.01), the decrease was higher in subepicardium than subendocardium so that theTGI decreased to 0. l7 l 0.04 (P<0.05). Wth the myocardium ischemia increased (4W6w and 8w after placing Ameroid constrictors), the %AII increased gradually, theincreased magnitUde of %AII from 2w to 4w was highest. The CVIB decreasedgradually, the decreased magnitude of subendocardium was higher than that ofsubepicardium. The TGI decreased highest from 2w to 4w and became zero at 8w(P<0.01). The changes of %AII and CVIB in grouP I before gene transfer was thesame as in control grouP. 8 weeks after placing Aineroid, the %AII decreasedgradually to 2.48t0.40 (P<0.0l); The CVIB increase to 4.37f2.24dB (P<0.0l), andthe increase was higher in subendocardiurn than that in subepicardiurn. The TGIincreased to 0. l4i 0.05 (P<0.0l). 2. Wth dobutamine stress, the %AII in two grouPschanged insignificamly. The CVIB of control grouP in normal state and at 2W 4wafter placing Aineroid increased significanly (P<0.0l, P<0.05 or P<0.05) whereasincreased at 6w and 8w insigniflcanly (P>0.05). The TGl increased significanly innormal state and at 2w (P<0.01 and P<0.05). The changes of CVIB of grouP I beforeveCtOr administration were the same as that of the control grouP. 2 weeks after genetTansfer during doblltaxnine stress, the transmural, subePicardia1 and subendocardicalCVIB increased insignificantly, but at 4w the transmural CVIB and TGI increasedsignificantly (P<0.0l). 3. DTI, two-dimensional color and M-mode showed the colorof normal myocardium brigh and filling, the color Stratification distinct. The color atischemic myocardium region were faint, local myocardia1 color lost and colorstratification clouding. After gene transfef, color filling of local my...
|
PDF Full Text Request