ABC | Volume 111, Nº5, November 2018

Original Article Albertini et al The role of preoperative venography in reoperations Arq Bras Cardiol. 2018; 111(5):686-696 Table 1 – Demographic and clinical characteristics of the study subjects Demographic and Clinical characteristics at baseline Male, n (%) 48% Age (years), means ± DP 58.5 ± 15.1 Caucasian, n (%) 82% Body mass index, means ± DP 25.7 ± 3.2 Functional class (NYHA), n (%) I 40% II 37% III 23% Structural heart disease, n (%) None 39% Chagas disease 23% Ischemic heart disease 8% Non-ischemic heart disease 24% Other 6% Associated comorbities None 20% Systemic arterial hypertension 62% Diabetes 17% Dyslipidemia 33% Coronary arterial disease 9% Valvopathy 7% Smoker (current) 1% Smoker (previously) 9% Medicines being used, n (%) Antiplatelet agents 33% Oral anticoagulants 12% Statins 39% Left ventricular ejection (%) means ± DP 53.4 ± 15.5 SD: Standard deviation; NYHA: New York Heart Association. lesion or subclavian vein occlusion; (3) whether lead extraction or other unconventional technique was required to gain access in cases of critical lesion affecting the subclavian vein, internal jugular vein and venous brachiocephalic trunk. Care Provided for Study Subjects The risks associated with the present study were related to the use of iodinated contrast media. Special care was taken to reduce the risk of renal damage following digital subtraction venography, although adverse reactions related to the use of non-ionic iodinated contrast agents are rare. Diabetic patients receiving oral hypoglycemic metformin hydrochloride were instructed to discontinue the use of that drug for 48 hours before the test and resume use 48 hours after the test. The cases of allergic reactions to iodinated contrast during or after the exams were treated according to the institution’s protocol for allergic reactions to contrast. Electronic Data Collection and Management The demographic, clinical and surgical data obtained were stored at the database developed in the REDCap system ( Research Electronic Data Capture ) 35 hosted at the hospital’s server. Variables Studied and Statistical Analysis The following data were analyzed as independent variables for the risk of occurrence of the outcomes studied: demographic data, preoperative clinical data at baseline, type of CIED, and type of procedure performed. The data recorded in the database (REDCap) were exported in the format of Excel worksheets ( Microsoft Excel ) and analyzed using SAS software ( Statistical Analysis System ). Initially all variables were analyzed descriptively. The quantitative variables were analyzed by considering the minimal and maximum values, means, standard deviation and median. The qualitative variables were analyzed by calculating the absolute and relative frequencies. We compared means using Student t-test, and tested homogeneity among the variable proportions using chi-square test. The significance level chosen for statistical tests was 5%. The outcomes of the study were described according to absolute and relative frequencies. The calculation of Odds Ratio (OR) and its confidence intervals at 95% were used as an effect measure between exposure variables and outcome development. Results Of 289 patients with an indication of reoperation involving the handling of leads, 100 were included in this study. (Figure 1) The population was balanced with regard to gender, had a predominance of Caucasian individuals (82%) and a mean age of 58.5 ± 15.1 years, with median 60. Most individuals studied were oligosymptomatic for heart failure (77%), with a left ventricular ejection fraction of 53.4 ± 15.5, 39% of which had no structural cardiac disease identified. Only 20% of cases did not have any comorbidity. One third of this population was using antiplatelet agents, while anticoagulants were used by 12% of the patients (Table 1). There was a balance in the number of cases with devices implanted on the right side (48%) and those on the left side (52%). Marking differences were observed, however, concerning time since implantation, with an average 14.3 ± 6.1 years for the right side, and 8.0 ± 7.9 years for the left side; as to the type of device, there were more conventional pacemakers on the right, while the four device types were more evenly distributed for the left side. (Table 2) Results of Digital Subtraction Venography Analyses of the venographies showed that 47 patients had significant venous lesions and that in 36 out of those there was venous collateral circulation. Moderate venous obstructions were observed in 23 exams, severe in 13, and occlusions in 11. Of the 53 patients without significant obstructions (< 50% of 688