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Objective:To study the feasibility of preserving the subvalvular structure during mitral valve replacement and whether it is more conducive to the recovery of cardiac function.Methods:The clinical data of 205 patients who underwent mitral valve replacement due to mitral insufficiency in Enshi Central Hospital from January 2017 to December 2020 were analyzed retrospectively. According to whether the subvalvular structure of mitral valve was preserved during operation, they were divided into three groups: group A was to preserve all the subvalvular structures of anterior and posterior mitral valve, group B retained all or part of the subvalvular structure of the posterior valve, in group C, all anterior and posterior subvalvular structures were removed. The operation time, cardiopulmonary bypass time and aortic occlusion time of patients in each group were counted. Postoperative ventilator use time, ICU stay time and incidence of complications; mitral flow velocities (MVE), left ventricular end diastolic dimension (LVED), left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were rechecked by echocardiography at 1 week, 3 months and 6 months after operation.Results:There were no significant differences in operation time, cardiopulmonary bypass time, aortic occlusion time, ventilator use time and ICU stay time among the three groups before surgery ( P>0.05). There were no death cases in perioperative period, and all patients were cured and discharged from hospital. The results of cardiac color ultrasound showed that MVE, LVED, LVEF and LVFS were improved compared with those before operation. Postoperative ultrasound results showed no significant difference in MVE at 1 week, 3 months and 6 months ( P>0.05). At 1 week after surgery, LVED in group A was lower than that in group B and C: (44.90 ± 5.59) mm vs. (46.13 ± 6.15) mm, (48.33 ± 5.59) mm. The difference was statistically significant ( P<0.05). Three months after operation, LVED and LVFS in group A were higher than those in group B and group C: (43.37 ± 5.61) mm vs. (44.69 ± 5.45) mm and (53.42 ± 5.35) mm, (33.92 ± 3.34)% vs. (31.67 ± 3.20)% and (30.37 ± 6.96)%, respectively. The differences were statistically significant ( P<0.05). At 6 months after operation, LVED in group A was lower than that in group B and group C: (41.86 ± 3.27) mm vs. (47.85 ± 6.93) mm and (53.42 ± 8.17) mm. LVFS was higher than that in group B and group C: (33.42 ± 2.64) % vs. (32.18 ± 5.98) % and (32.28 ± 2.58) %, and the differences were statistically significant ( P<0.05). Conclusions:Preserving the whole subvalvular structure of mitral valve will not lead to prosthetic valve dysfunction and increase surgical complications. After operation, it showed better reduction of left ventricular end diastolic diameter and better left ventricular shortening rate, which was more conducive to the recovery of cardiac function.
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Objective To construct a large animal model of ischemic heart disease induced by acute myocardial infarction (AMI) . Methods Male Diannan Mini-pigs were selected (n=8), weight 20 ± 4 Kg. After general anesthesia and endotracheal intubation, blood pressure and electrocardiograph were monitored. Parasternal incision was taken and thoracotomyv was performed at 4th-to-5th intercostalgap. Pericardium was opened and left anterior descending artery was ligated. Echocardiography was performed at baseline, postoperative 28 and 60 day. Euthanasia and heart explanted was conducted at 60 day of experimental pig. After gross examination of the heart, the histological examination was used to assess myocardial infarction by using H&E staining. Results All of the pigs were presented with ventricular arrhythmias in varying degrees after ligation of the left anterior descending artery, of whom 2 died of refractory ventricular fibrillation, the mortality was 25%. Echocardiography assessment showed the loss left ventricular function, the thinning of left ventricular apical and the enlargement of left ventricule. Histological examination revealed that myocardial fibrosis and fibrous scar were formed in myocardial infarction area. Conclusion The ligation of left anterior descending artery through thoracotomy under direct vision is a reliable strategy for construction of AMI porcine model and the experimental porcine can develop ischemic cardiac dysfunction progressively.