ABC | Volume 114, Nº6, June 2020

Original Article Yang et al Chemotherapy-related coronary-artery disease Arq Bras Cardiol. 2020; 114(6):1004-1012 our study, half of lung cancer patients were smokers, which is consistent with national data, showing that about 57% of lung cancer diagnosed patients were either current or former smokers. 36 In the study, other cardiovascular risk factors have shown to be likely to increase the severity of CAD. However, those risk factors did not show obvious statistical significance for increasing the SXscore. On the other hand, smoking showed a more significant effect, by increasing the risk for SXhigh by 3.646 times. Moreover, the length of time of lung cancer may play a role in the progression of CAD. In the study, we collected the data on the time interval between cancer diagnosis and CAG. Although the time interval between cancer diagnosis and CAG was discrepant between the two groups (possibly because this is a small retrospective study), the multivariate logistic analysis, adjusted for the time interval variable, showed a significant difference regarding CAD severity between patients with chemotherapy and those without chemotherapy. Our study has several limitations. First, it was a small sample single-center study, performed among a specific population of patients, who had had lung cancers and who required CAG due to suspected severe CAD. A lower number of patients received radiotherapy: among the 94 study patients, 21 used to receive radiotherapy. In particular, only 4 patients (6.9%) had a history of radiotherapy in the non-chemotherapy group. Therefore, the results from this specific small sample may be deviant. Second, it was a retrospective study, thus some valuable information on the study patients might be lacking. For instance, it would be helpful to know the stage of lung cancer at initial presentation, since those who received chemotherapy could have had more advanced disease and, consequently, more inflammation for a longer period of time, which may promote atherosclerosis and contribute to the results observed. However, we were not able to obtain such comprehensive information on the patients. Third, we did not investigate whether the SXscore was associated with long- term cardiovascular events in the study patients. Additional prospective, large-scale clinical studies may be required to verify the effect of chemotherapy on the anatomical abnormality of CAD and the underlying mechanisms of chemotherapy-related CAD. Conclusions In brief, the present study demonstrates that chemotherapy is associated with long-term anatomical complexity and CAD severity. The results could partly explain why cancer patients with a history of chemotherapy are at higher risk of suffering coronary events compared to those with no history of chemotherapy. However, due to the limitations mentioned, a large-scale prospective study, as well as further pathophysiological and molecular researches, are needed to further illustrate the association between chemotherapy and CAD, and the underlying mechanisms of chemotherapy- related CAD. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding This study was funded by National Natural Science Foundation of China, number 81770237. Study Association This article is a part of the master dissertation of Qian Yang from Chinese PLA general hospital. Author contributions Conception and design of the research: Chen Y, Hu S; Acquisition of data: Yang Q, Gao H, Zhang M, Jing J, Zhu P; Analysis and interpretation of the data: Yang Q, Gao H, Zhang J, Zhou H, Hu S; Statistical analysis: Zhang J, Zhou H, Hu S; Obtaining financing: Hu S; Writing of the manuscript: Zhang J, Hu S; Critical revision of the manuscript for intellectual content: Yang Q, Chen Y, Hu S. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Chinese PLA General Hospital under the protocol number 52019-223-02. All the procedures in this study were in accordancewith the 1975Helsinki Declaration, updated in 2013. Table 4 – Multivariate stepwise logistic-regression model for anatomical severity of the coronary artery among lung cancer patients Variables OR 95% CI p value Total patients (n=94) Smoking 3.646 1.374-9.678 0.009 Chemotherapy 5.323 2.002-14.152 0.001 Patients except with TKI or NVR (n=86) Smoking 3.670 1.303-10.339 0.14 Chemotherapy 5.850 2.027-16.879 0.007 TKI: Tyrosine kinase inhibitors; NVR: Not verified regimens 1010