Objective Analyze the causes of the conversion from off-pump coronary artery bypass (OPCAB) to on-pump coronary artery bypass grafting (ONCAB), in order to improve the operative survival rate. Methods From January 2000 to December 2003, 1952 patients underwent OPCAB. 29 patients (1.49%) required conversion from OPCAB to ONCAB. The causes of conversion included ventricular fibrillation in 5 cases, and hypotension in 24 cases. 26 patients received CABG under CPB. 8 patients under aortic cross clamping, and 3 patients needed only CPB support. Results The mean number of grafts was 2.9?0.6. 9 patients died, postoperatively with a mortality rate of 31.03%. In patients with the perioperative blood pressure lower than 80/40?mm?Hg, the mortality rate was 47.6%, and in patients with blood pressure higher than 80/40?mm?Hg, the mortality rate was 8.33% (P=0.043). No one with duration of hypotension less than 15min died, the mortality of the patients with hypotension times more than 15min was 42.86% (P=0.029). In the death group, all the patients had more than three vessel disease and severe vessel stenosis or occlusion. The mortality was hither in female patients. Conclusion Patients converting from OPCAB to ONCAB had a higher mortality. The severity and lasting time of hypotension is closely correlated with the mortality rate. The high risk factors included the surgeons with less OPCAB experience, the patients with more than three vessel diseases and severe coronary stenosis or occlusion, and female patients. The indication of OPCAB must be strictly controlled. Hypotension and severe ventricular fibrillation occurred during OPCAB must be corrected and eliminated immediately.

Objective:To investigate the diagnostic value of synthetic MRI methods in the differentiation of benign and malignant breast lesions.Methods:Clinical and imaging data of 93 breast patients confirmed by pathology in the Second Affifiliated Hospital of Xi′an Jiaotong University from May 2019 to April 2020 were analyzed retrospectively. All patients underwent synthetic MRI technique, and the quantitative parameters of T 1, T 2, and proton density (PD) values were measured. Independent samples t-test and Wilcoxon test were used to compare the differences in clinical and imaging characteristics between the benign and malignant breast lesions. ROC curve was used for the comparison of the diagnostic efficacy of the quantitative parameters in differentiating malignant from benign breast lesions. Results:Of the 93 patients with breast lesions, 62 cases were malignant and 31 cases were benign. The quantitative T 2 values for benign and malignant lesions were 103 (93, 126)ms and 83 (77, 90)ms respectively, and the quantitative PD values were 87.7 (72.7, 96.7)pu and 73.5(63.3, 79.4)pu respectively. There were statistically significant differences between benign and malignant lesion( P<0.05). Taking quantitative T 2 values of 90.5 ms and PD values of 84.8 pu as the cut-off value, the area under the ROC curve in differentiating benign from malignant breast lesions were 0.87 and 0.75, accuracy values were 80.6% and 78.5%, specificity values were 87.1% and 54.8%, sensitivity values were 77.4% and 90.3% respectively. Conclusion:Synthetic MRI methods can be applied in the examination of breast lesions and has the potential to be an effective diagnostic method for the differential diagnosis between benign and malignant lesions of breast.