IJCS | Volume 31, Nº2, March / April 2018

98 Balzan et al. Atherosclerosis in the internal thoracic artery Int J Cardiovasc Sci. 2018;31(2)97-106 Original Article Following the establishment of the criteria for surgical indication, one should proceed to choose the type of graft to be used by the surgeon. Among the arterial options, the best choice is the internal thoracic artery. 2 In 1986, a study performed at the Cleveland Clinic demonstrated superiority in the use of the LITA, or left internal thoracic artery, compared to the use of the saphenous vein when anastomosed to the left anterior descending branch of the left coronary artery, with patency indices (90%) in 10 years. 3 This study was confirmed by Boylan MJ et al, 4 with a 20-year follow-up and maintenance of patency rates of around 90% of patients undergoing LITA graft surgery. Studies indicate that only 4% of LITA present atherosclerosis, and only 1% are consideredmajor stenoses. 5 The possible disadvantages are the presence of spasms, possibility of atrophy when used to revascularize an artery without significant stenosis, and in case of bilateral use (LITA and right internal thoracic artery), a possible increase in the incidence of sternal infections in obese and diabetic patients. 2 On the other hand, the PREVENT IV study observed 1539 patients undergoing myocardial revascularization, with LITA grafting for 12-18 months after surgery, evidencing a considerable rate of graft failure in LITA of about 8.6%. 6 Recently, Shavadia et al. 7 (2015), followed 5276 patients who underwent coronary artery bypass grafting, where 281 patients had graft failure after 12 months of follow-up, demonstrating the presence of lesions that made the use of the LITA unfeasible. This is an analytical, cross-sectional, prevalence study performed through the analysis of images by interventional cardiologists obtained through angiography, which quantified the prevalence of left internal thoracic artery stenosis in patients submitted to coronary artery bypass grafting (CABG). The images analyzed were from patients who were admitted to the hemodynamic service between January 2012 and August 2016. Methods The study was carried out with patients who underwent coronary angiography at the hemodynamics department of the Centro de Diagnósticos Paraná - CEDIPAR - Hospital Paraná, in the city of Maringá, PR. Patients were selected independently of age, sex and comorbidities, and were indicated by interventional cardiologists of the CEDIPAR hemodynamic service to surgical correction of the lesions, CABG, based on the severity of the coronary artery lesions found. After completion of the cardiac catheterization examination by radial route, and the need for coronary artery bypass grafting was confirmed, a Simmons 1 or 2 catheter was inserted, depending on the conformation of the aortic arch of the patient, and a selective catheterization of the artery left subclavian and internal thoracic with manual injection or through injection pump, of approximately 10mL of contrast, iodixanol. Data were collected from all patients in the study, including comorbidities and life habits, such as smoking, sedentarism, diabetes mellitus type 1 and 2, systemic arterial hypertension, hypercholesterolemia, previous history of AMI with supra-ST-segment elevation, without ST-segment elevation, and previous ischemic and hemorrhagic stroke. The degree of stenosis of the LITAwas not evaluated, considering only the presence or absence of lesion. This data was organized and tabulated using the Microsoft Excel 2010 ® program. The primary objective of this study was to identify the presence of atherosclerotic lesions in the LITA, analyzed by means of angiography, in patients with indication for coronary artery bypass grafting, and the quantification of lesions that would not allow LITA to be used as a graft for the anterior descending branch of the left coronary artery. The following study respected ethical standards, since it was submitted to the ethics and research committee, through the Plataforma Brasil ® applying the free and informed consent form for all patients, and its approval was registered by opinion 1,651,761 (CAAE: 57529416.0.0000.5539). Statistical analysis Patients were divided into groups with and without changes in the LITA. Categorical variables were described in percentages and groups compared with chi-square test and Fisher's exact test. The only continuous variable, age, was tested for normality by the Kolmogorov-Smirnov test and, because it had no normal distribution, was described in the median (P25; P75) and the groups compared with the Mann-Whitney test. The level of statistical significance was p < 0.05. The analyzes were performed in SPSS ® software version 20. Results This study analyzed the prevalence of atherosclerotic lesions and other lesions that made the use of the LITA unfeasible in 39 patients who were candidates for CABG. The median age (25th percentile, 75th percentile) of the