| Objective:In the past 50 years, the incidence of breast cancer has been rising slowly and it reaches the first one of female malignancy. Surgery combined with radiotherapy or chemotherapy has improved the treatment outcome of breast cancer patients. Among the many chemotherapy drugs, anthracycline(ACT) is a highly effective anti-cancer one to treat the diseases of hematopoietic system and solid tumors and plays an important role to improve the cure rate and survival rate of breast cancer patients. However, the cardiotoxicity induced by ACT limits it's dosage. According to the WHO standard of anti-cancer drug-induced toxicity,the evaluation of cardiotoxicity mainly depends on the routine echocardiography systolic parameters,but which cannot show obvious changes during the early damaged period. Tei index is a new parameter that can integratively evaluate left ventricular systolic and diastolic functions. This study measured the isovolumic contraction time(ICT),isovolumic relaxation time(IRT) and ejection time(ET) of each patient before and after chemotherapy at the end of the second,fourth,sixth courses by using free angle M-mode(FAM) and tissue doppler imaging(TDI) echocardiography respectively. Late, Tei index, isovolumetric contraction index (ICT/ET) and isovolumetric relaxation index (IRT/ET) were computed automatically by ultrasonic system. Then combined with some traditional parameters together integratively evaluate left ventricular function of breast cancer patients. Finally,we evaluated the merits and demerits of the two methods respectively and the linear correlation between them,and tried to discuss how to improve the accuracy of measurement of Tei index.Methods:There were 72 breast cancer patients without cardiovascular diseases before chemotherapy. Among them, 25 patients were treated by ACT only and completely finished 6 courses of chemotherapy,age 28～61 years, 45.96±9.28 years.Instrument: All data were gained by using ALOKAα-10 colour doppler ultrasonic system with a 2.5MHz probe, and were saved by Medex ultrasonic imaging information system.At first we measured and noted heart-rate (HR), left atrium dimension (LADs), left ventricular internal dimension (LVIDd), the thickness of interventricular septum (IVSd) and left ventricular posterior wall (LVPWd) at end diastole by conventional 2-dimension echocardiography. Next,left ventricular ejection fraction(EF),stroke volume (SV) and E/A ratio were assessed by using Teichholz method in the M-mode and pulse doppler echocardiography in apical 4-chamber views. Then we measured isovolumic contraction time (ICT),isovolumic relaxation time (IRT) and ejection time (ET) by using FAM and TDI methods. At last,left ventricular Tei index, ICT/ET and IRT/ET were computed automatically by ultrasonic system.Statistical analysis: All statistical analysis was performed with SPSS13.0 software. All data were expressed as mean±SD. When compared means before and after chemotherapy at the end of the second, fourth, sixth courses, we adopted paired-samples T test. Linear correlation and regression analysis were performed to display certain relationship between two parameters. A value of P <0.05 was considered significant.Results:There was no statistical difference between Tei index obtained by free angle M-mode and tissue doppler imaging, and there was a close correlation between them. Correlation coefficient equals 0.811(P<0.05). Tei index gradually increased with the drugs'cumulative dosage,and the linear regression equation between them could be showed Y=0.353+0.027X . The significant difference of Tei index and IRT/ET didn't occur until at the end of the fourth course and the difference increased with time,but without significant difference in the index of ICT / ET from start to finish. Conventional echocardiography showed that the parameters of left ventricular systolic function after anthracycline chemotherapy at the end of the second,fourth,sixth courses were not significantly different compared with those before chemotherapy respectively. However, the abnormalities of routine diastolic function index of left ventricle was seen in only 3 patients at the end of the fourth course and 5 patients at the end of the sixth course respectively.Conclusions:Tei index gradually increased with the drugs'cumulative dosage. Compared with conventional echocardiography, Tei indexes are more sensitive in detecting abnormalities of cardiac function in breast cancer patients treated with anthracycline. There was no statistical difference between Tei index obtained by using FAM and TDI, and the two methods showed a close correlation. Furthermore,free angle M-mode echocardiography is a more convenient and more visualized method to measure Tei index. |
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