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 recirculation in thoracic computed tomography images, these methods are not as accurate as digital venography to quantify and define where obstructions are located and any collateral circulation developed . 31-34 This study is part of a prospective registry, with data derived from medical practice, and its goals are: (1) to identify the prevalence, degree and location of venous lesions in CIED patients with an indication of reoperation; (2) to identify predisposing factors of these venographic changes; and (3) to define the role of digital subtraction venography when intravascular reinterventions are planned in individuals with leads previously implanted. Methods Study Design and Population This is a cross-section analysis derived from a cohort where thromboembolic complications are studied in patients submitted to lead revision or upgraded procedures. This study was conducted in a high-complexity cardiology hospital and it was approved by that hospital’s Committee of Ethics in Research. All subjects signed a free and informed consent form. From April 2013 to July 2016, patients who met the following criteria were consecutively included: (1) having CIED implanted at the territory of the superior vena cava for more than six months; (2) being between 18 and 90 years of age; (3) having an indication for lead revision or upgrade procedures. The following candidates were not included: (1) individuals with creatinine > 1.5 mg/dL due to the risk of renal damage from iodinated contrast; (2) candidates that had known allergy to iodinated contrast media; and (3) those who declined to participate in the study. Considering the high rates of venous lesions in these patients, a convenience sample of 100 patients was defined to detect the outcomes studied. Study Outcomes The outcomes of the study included: (1) venographic findings of significant venous obstructions and collateral circulation, and (2) usefulness of the preoperative venographic findings when planning and performing the surgical procedure. Study Workflow Patients with an indication of reoperation for implantation of additional leads, replacement or removal of previously‑implanted transvenous leads, and who met the eligibility to the study were submitted to preoperative evaluation comprising patient background assessment, clinical evaluation and evaluation of imaging exams. Thorax radiography was conducted to help determining the position of the leads in use or abandoned. The venous system was evaluated using digital subtraction venography through images acquired with an Allura DSA unit or Allura Xper FD20 (Philips, The Netherlands) to bilaterally assess the axillary, cephalic, subclavian, innominate (or brachiocephalic trunk) veins, and superior vena cava. Continuous infusion of low-osmolality nonionic iodinated contrast media (Visipaque-Iodixanol, 320 [652 mg/mL Iodixanol], GE, Healthcare, Europe) was performed using a MEDRAD injection pump with controlled volume (100 mL to 120 mL) and infusion speed (10 mL/s at 600 psi pressure). All exams were simultaneously evaluated by two specialists: a Vascular Interventional Radiologist and a Cardiac Pacing Specialist. The images obtainedwere classified according to the presence or absence of venous lesions and of collateral circulation. Venous lesions were classified according to their stenosis level: without significant alteration (<50%),moderate stenosis (51-70%), severe stenosis (71-99%), and occlusion (100%). Surgical Procedures Surgical procedures were performed according to the hospital’s usual routines, always under the supervision of an anesthesiologist. Operations were grouped in three main types: (1) Implanting new leads without further removal (due to dysfunction of a previously implanted lead, or upgrade procedures); (2) Replacing leads with the removal of previously implanted leads; or (3) Isolated lead extraction. Operations were planned according to the radiological function of the venous territory obtained through venography: (1) In cases where the venous pattern was deemed without significant lesions or with moderate lesions, no special care was taken to implant new leads and, similarly, the decision of removing a deactivated lead was made at the surgical team’s discretion. (2) In cases with stenosis deemed severe or occlusions, surgical planning considered: a) careful evaluation of the venography to check the possibility of using the ipsilateral internal jugular vein; b) preparing the patient for transvenous lead extraction to provide access for the new lead when using the ipsilateral internal jugular was not possible; c) reserving material for attempts to go beyond a lesion and perform venous dilation. The decision whether to remove or abandon in situ the previously abandoned leads or the ones that would be deactivated in the current surgical procedure was made considering the following criteria: (1) patient’s age and life expectancy; (2) number of leads remaining in the superior vena cava at the end of the surgical procedure performed in this study; (3) risk of worsening the lesions observed in the venography. Although the criteria for defining an access to deactivated leads and whether to remove or abandon them were previously discussed with the surgical team involved in the study, the final decision on both topics was to be made by the team itself during the procedure due to the intraoperative findings and technical resources available. Agreement between Planned and Actually Performed Procedure To assess the agreement between the procedure planned according with the venography findings and the procedure actually performed, three conditions were considered: (1) possibility of access to the heart by the subclavian vein without any special strategies; (2) possibility of access to the heart by the ipsilateral internal jugular vein when there was a severe 687