Abstract: Objective To evaluate myocardial protection effect of different myocardial protective strategies for patients undergoing double valve replacement （DVR） . Methods From Jun. 2005 to Dec. 2005, 32 patients with predominant aortic valve stenosis undergoing DVR in Xinqiao Hospital were included in this study. These patients were randomly divided into four groups with 8 patients in each group： （1） antegrade perfusion group：Cold-blood cardioplegia was delivered antegradely through aortic root, and mitral valve replacement （MVR）was performed. Then cold-blood cardioplegia was delivered antegradely through left and right coronary ostia, and aortic valve replacement （AVR） was performed； （2）retrograde perfusion group：Cold-blood cardioplegia was delivered retrogradely and intermittently through coronary sinus, and DVR was performed； （3）antegrade＋retrograde perfusion group：The route of cold-blood cardioplegic infusion was antegrade during MVR procedure first and then retrograde during AVR procedure；and （4）beating heart group：Oxygenated blood from cardiopulmonary bypass machine was delivered retrogradely and continuously through coronary sinus, and DVR was performed with beating heart. Early clinical outcomes were observed. Serum cardiac troponin I （cTnI） was measured by enzyme-linked immunosorbent assay（ELISA）. Serum creatine kinase-MB （CK-MB） and myocardial lactic acid release rate were measured by Hitachi7150 Automatic Chemistry Analyzer. Myocardial mitochondria malondialdehyde （MDA） level was measured through thiobarbituric acid reagent species analysis. Results All the 32 patients survived their surgery and were discharged successfully. Myocardial lactic acid release rate at 80 min after aortic cross-clamping, serum cTnI and CK-MB on the first postoperative day, myocardial mitochondria MDA levels of beating heart group were 13.59%±6.27%,（1.17±0.25） ng/ml, （56.43±16.50） U/L and（2.18±1.23） nmol/（ng.prot）respectively, all significantly lower than those of retrograde perfusion group ［（33.49%±8.29%, （1.82±0.58 ）ng/ml, （78.31±21.27） U/L （5.07±2.35） nmol/（ng.prot），P＜0.05］ and antegrade＋retrograde perfusion group［20.87%±7.22%, （1.49±0.23） ng/ml,（66.67±19.13） U/L,（4.34±1.73） nmol/（ng.prot），P＜0.05］, but not statistically different from those of antegrade perfusion group ［18.83%±5.97%, （1.41±0.32） ng/ml, （63.21±37.52） U/L, （3.46±1.62） nmol/ （ng.prot），P＞0.05］. Conclusion All the four myocardial protective strategies are effective myocardial protection methods for DVR patients. Continuous retrograde perfusion with beating heart and intermittent antegrade perfusion can provide better myocardial protection, and therefore are preferred for DVR patients. The combination of antegrade and retrograde perfusion is easy to administer and does not negatively influence surgical procedures. Retrograde perfusion is also effective as it takes only a short time.
Objective To investigate surgical treatment strategies and analyze clinical outcomes of cardiac tumors. Methods Clinical data of 181 patients with cardiac tumors who underwent surgical treatment in Xinqiao Hospital of Third Military Medical University from January 1980 to December 2010 were analyzed retrospectively. There were 79 malepatients and 102 female patients with their age of 10 months-76 years （45.22±18.21 years） . A total of 179 patients underwent180 tumor resection surgeries under cardiopulmonary bypass （CPB）. Two patients with malignant tumors did notreceive surgical resection but exploratory thoracotomy. All the tumor specimens were examined by pathologists. ResultsThere were 169 patients （93.4%） with primary cardiac tumors, including 144 patients （79. 6%） with myxoma, 20 patients （11.0%） with other types of primary benign cardiac tumors, and 5 patients （2.8%） with primary malignant cardiac tumors. There were 12 patients （6.6%） with secondary cardiac tumors. There were 2 perioperative deaths （1.1%） in patients with primary cardiac tumors，including 1 patient with low cardiac output syndrome and another patient with postoperative multipleorgan dysfunction syndrome. All the 5 patients with primary malignant tumors died in postoperative 12 months. Patients with benign cardiac tumors were followed up for 6 months-15 years （2.41±1.08 years） without tumor recurrence. Among patients with secondary cardiac tumors，there was 1 perioperative death because of postoperative multiple organ dysfunction syndrome，2 patients died within postoperative 1 year, and 3 patients died in the 3rd postoperative year during follow-up. Conclusion Myxoma is the most common cardiac tumor. Complete surgical resection is the best treatment strategy forpatients with cardiac tumors. Clinical outcomes of patients with benign cardiac tumors are significantly better than those with malignant cardiac tumors. Prognosis of patients with primary malignant cardiac tumors is poor.
Objective To establish the three-dimensional (3D) finite element model of the knee joint including posterolateral complex (PLC), and to simulate the reconstruction biomechanical analysis in this model. Methods The knee of a 26-year-old healthy man was scanned by MRI to obtain the image data of the knee in the coronal, sagittal, and axial position. First, Mimics10.01 and Hyperworks 8.0 softwares were used to extract each slice profile data of the knee joint in a two-dimensional image data respectively and to establish 3D geometric model of bone, meniscus, articular cartilage, and ligament. Second, Unigraphics software NX 4.0 was used to establish a 3D finite element model of knee joint, which had the functions of Mesh, material properties, component connection, and contact definition. Third, displacement measurement on the model and reconstructing biomechanical analysis for PLC simulation were performed. Results The 3D finite element model of the knee joint including PLC was established successfully. Under 134 N forward force, the tibia forward displacement was 4.83 mm. PLC simulation reconstruction biomechanical analysis of the 3D finite element model of the knee joint showed that under 10 N·m varus and external rotation torque conditions, the knee varus and external rotation angles of simulation reconstruction were greater than those of the intact knee, and less than those of PLC missing. Conclusion The 3D finite element model of the knee joint including PLC can be established by the reverse engineering, and it is valid and can be used as the basis for the biomechanical properties to analog reconstruction of PLC.