经导管法冠脉内微球灌注建立小型猪慢性缺血性心力衰竭模型研究

目的应用选择性冠状动脉前降支(LAD)内微球分次灌注方法造成心肌缺血坏死,探索建立稳定存活的小型猪慢性缺血性心力衰竭(CIHF)动物模型。方法选择15头8~11个月龄的中国五指山小型猪,体重20~30kg,采用4FJudkins导管行冠状动脉造影(CAG)并超选LAD,于LAD内行塑料微球悬液分次注入(1ml/次,约含1·0×105个微球),间隔10min重复注射,直到LAD前向血流减慢,TIMI血流≤2级,LVEDP升高至15mmHg~18mmHg时停止,同时监测心电图、有创血流动力学参数及心肌损伤标志物(CK-MB、cTnI)变化。应用心脏超声分别于制模前、制模后10、20、30、40、50、60d分别测量LVEF。并于制模前和术后2个月应用Swans-Ganz漂浮导管测量mRAP、mRVP,平均右房压(mRAP)、平均右室压(mRVP)、平均肺动脉压(mPAP)及肺毛细血管楔嵌压(PCWP)及CO,并行左室造影测量左室舒张末压(LVEDP)的变化,比较CIHF动物模型成功前后的血流动力学变化。认定和评价模型成功率、稳定性和可重复性。并行心脏剖检测定梗死心肌面积和病理检查。结果制模2个月后共有11头小型猪成活,其中10头达到CIHF动物模型标准(LVEDP>18mmHg和CO下降30%以上),模型成功率为66·7%(10/15),微球注射次数(3·2±0·9)次,总量(3·2±0·9)×105个。制模2个月时与制模前相比,LVEF下降38·5%,LVEDP升高197·8%,CO下降46·8%,(P<0·01)。与模型制作前相比,模型成功后血流动力学检查显示:mRAP、mRVP、mPAP和PCWP均明显升高(P均<0·01)。病理检查显示心肌坏死面积占左心室面积的25·4%~34·9%。光镜显示左心室前壁及心尖部心内膜下心肌血管内散在的半透明微球阻塞,伴灶性凝固性坏死,并呈现缺血性坏死心肌和慢性纤维胶原增生的病理特征。结论超选冠状动脉LAD内微球分次灌注方法制作的小型猪CIHF模型具有闭胸、高成功率、稳定和重复性好等优点,较药物、冠状动脉结扎和起搏诱导的心力衰竭模型更接近临床CIHF病理生理学特点和病程。

Experimental research on establishing chronic ischemic heart failure model of minipig with intracoronary perfusion of plastic microspheres by catheterization

OBJECTIVE: To establish a stable chronic ischemic heart failure (CIHF) model of minipig caused by gradual myocardial ischemia and necrosis that was achieved with repetitive microspheres perfusion in left anterior descending artery (LAD). METHODS: A total of fifteen Wuzhishan minipigs original in Hainan China (8 to 11 months old with body weight of 20 to 30 kg) were used. The 4F angiographic catheter was superselectively engaged in LAD, and 1 ml of suspending plastic microspheres fluid were given repeatedly at ten-minute intervals, which include microspheres 1.0 x 10(5)/ml, until LVEDP raising and maintaining from 15 mm Hg to 18 mm Hg and TIMI flow was less than or equal to grade 2. Electrocardiography, hemodynamic parameters, CK-MB and cTnT were monitored during the procedure. LVEF was repeatedly measured with ultracardiography at 10 d, 20 d, 30 d, 40 d, 50 d, 60 d after establishing chronic ischemic heart failure model. Meanwhile, hemodynamic indices including mRAP, mRVP, mPAP, PCWP and CO (thermo-dilution method) were measured before and two months after procedure. The success rate, stability and repetition of chronic ischemic heart failure model were identified and evaluated. Finally, myocardial infarcted area was measured and myocardial pathologic examination was investigated. RESULTS: Eleven minipigs survived two months after procedure. There were ten minipigs accorded with the criteria (LVEDP > 18 mm Hg CO reduced by 30%) of the CIHF model and the success rate was 66.7% with a mean of 3.2 +/- 0.9 times of microspheres injections and total doses of (3.2 +/- 0.9) x 10(5) microspheres. This resulted in 38.5% reduction in LVEF, 197.8% elevation in LVEDP and 46.8% declining in CO from baseline values (P < 0.01), while mRAP, mRVP, mPAP and PCWP increased significantly as compared with those before procedure. Cross myocardium pathology showed the ratio of necrosis area to left ventricle (LV) area was 25.4% - 34.9% (mean 28.6%) and light microscopy examination of LV myocardium revealed that intravascular semitransparent plastic microspheres distributed throughout subendocardium of left ventricular anterior and apical parts, with more numerous focal myofiber necrosis, which characterized by pathologic founding of ischemic necrosis of myocardium with fibre proliferation. CONCLUSION: A stable CIHF model could be established in Chinese Wuzhishan minipigs with intra-coronary microspheres perfusion via superselectively engaging in LAD, which was prior to those of drug-induced, tachycardia-pacing induced or coronary artery ligation-induced, and had the advantages of stability, closed chest, mild trauma higher success rate and easy for repetition. It might be suitable for using the research of CIHF as large reliable experimental animal model.