Efficacy Analysis of a Script-based Guide for EVAR Execution: is it Possible to Reduce Patient Exposure to Contrast, Operative Time and Blood Loss even when Advanced Technologies are not Available?

ABSTRACT INTRODUCTION: Despite the patient and medical staff exposure to radiation in endovascular aneurysm repair, the benefits of this abdominal aortic aneurysm type of surgical management are justfied by minor recovery time and hospitalization, as well as an option for patients not elected to conventional open repair. In this minimally invasive surgical aproach, time of procedure and radiation doses can be substantial - and the increasing frequency of these procedures and it's complexity have impelled vascular surgeons to face additional and successive risk to occupational radiation exposure. Meticulous study of the computed tomography angiography during the endovascular aneurysm repair preparation allows reduction of unnecessary radiation exposure, as also reduces consecutive image acquisition and contrast use (that may be related to renal overload in susceptible patients). Some studies have proposed strategies to optimize endovascular intervention to reduce contrast use and X-ray exposure. Although they might prove to be effective, they rely on use of additional specific and advanced equipment, available only in major centers. As an alternative to this expensive and restrict technology, it is presented a simpler technique through image manipulation on software OsiriX, aiming to reduce both exposures. OBJECTIVE: To analyze the efficacy of the adoption of a study protocol and a script-based guide in preparation for endovascular aneurysm repair through verifying it's impact over the surgical procedure - as referred to intravascular contrast infuse, effects over renal function, blood loss and operatory time. METHODS: A longitudinal prospective study from March 2014 through March 2015, where 30 performed endovascular aneurysm repair were compared to a historic control group. The planning for endovascular aneurysm repair through the patient's tomographic image manipulation in the prospective group was performed with OsiriX MD software. A script-based guide upon gathering detailed computed tomography angiography images was elaborated by the author and distributed to the performing surgical team for appreciation, instruction and pre operatory judgment. Based upon the script, the C-arm gantry angle was specifically corrected in each case of endovascular aneurysm repair, for image optimization and aneurysm's neck visualization. Arteriography was performed under digital subtraction angiography after catheters were positioned according to predicted level description in the referred guide. Statistical analysis were performed with a significance level of 5% (P value<0.05). RESULTS: There was a statistically significant relationship between the two studied periods and the variables: contrast volume (284.5 vs. 31.8 mL), operative time (207.5 vs. 140.4 min.) and blood loss (798.1 vs. 204.4 mL), revealing that they are considerably larger in the historical control group than in the script guided current group. There was no difference related to the volume of contrast used in the two groups and the occurrence of renal impairment. CONCLUSION: In the present paper it was possible to demonstrate the impact of the ability to manipulate digital formats of medical images without the need of sophisticated equipment, in adoption of a guide based on the compilation of informations collected with assistance of an accessible software performed on a personal computer. Although we could not prove relation to occurrence of renal impairment, there were direct results on reduction of intravascular contrast use, even as surgical time and blood loss, compared to a previous historical period.

Avoiding pitfalls of intraoperative peripheral endovascular surgery with the aid of OsiriX: expanding the use of virtual fluoroscopy / Como evitar armadilhas do intraoperatório em cirurgia endovascular periférica com o auxílio do OsiriX: ampliando o uso da fluoroscopia virtual

We have shown how the analysis of the angiotomography reconstruction through OsiriX program has assisted in endovascular perioperative programming. We presented its application in situations when an unexpected existence of metallic overlapping artifact (orthopedic osteosynthesis) compromised the adequate visualization of the arterial lesion during the procedure. Through manipulation upon OsiriX software, with assistance of preview under virtual fluoroscopy, it was possible to obtain the angles that would avoid this juxtaposition. These angles were reproduced in the C-arm, allowing visualization of the occluded segment, reducing the need for repeated image acquisitions and contrast overload, allowing the continuation of the procedure.

Temos demonstrado como a análise da reconstrução da angiotomografia utilizando o programa OsiriX tem auxiliado na programação perioperatória endovascular. Apresentamos aqui sua aplicação em situação em que a existência de artefato metálico (osteossíntese ortopédica) comprometia a adequada visibilização de lesão arterial durante o procedimento. Pela manipulação da angiotomografia no software OsiriX e com o auxílio das imagens sob fluoroscopia virtual foi possível obter-se automaticamente uma angulação que evitasse esta justaposição. Os ângulos foram reproduzidos no arcoscópio, o que permitiu expor o segmento ocluído, reduzindo a sobrecarga de contraste e de repetidas tomadas, permitindo a continuação do procedimento.

Proposta de correção virtual geométrica da projeção ostial da artéria renal no estudo operatório de aneurismas infrarrenais: resultados iniciais de um estudo piloto / Proposal of renal artery's ostial projection under virtual geometric correction in infrarenal aneurysms: initial results of a pilot study

Introdução: Para o preparo pré-operatório endovascular dos aneurismas infrarrenais é necessária a mensuração acurada de suas características anatômicas e morfológicas, alcançada com o uso de softwares avançados em manipulação de imagens de tomografias multicanais. Este processo permite também o estudo acurado das relações anatômicas das demais artérias do eixo aorto-ilíaco. Uma visualização perpendicular à origem da artéria renal mais baixa possibilita o uso de toda a extensão do colo para fixação da endoprótese e selamento proximal, o que pode ser previsto durante o estudo da tomografia, impedindo um posicionamento subótimo e a sobreposição das estruturas vasculares no intraoperatório. Expõem-se aqui os resultados iniciais de um projeto piloto, envolvendo manipulação de imagens tomográficas, na correção ortogonal da artéria renal aplicada à orientação radioscópica no intraoperatório. Métodos: Por meio de reconstrução multiplanar de imagens tomográficas em software obtém-se um corte axial em ângulo reto. Conceitos geométricos de triangulação virtual promovem a correção ortogonal em três dimensões da visualização ostial da artéria renal, que pode ser reproduzida intraoperatoriamente, através do reposicionamento do arco cirúrgico. Resultados/Discussão: Embora alguns autores argumentem que a anatomia do vaso observada na tomografia possa mudar durante o intraoperatório, sabe-se que o posicionamento angular das artérias renais não se modifica, mesmo após a inserção dos fios guia rígidos, introdutores e da própria endoprótese. Assim, acreditamos ser possível, por meio de ...

Introduction: Endovascular aneurysm repair requires the precise deployment of the graft. In order to achieve accurate positioning, the anatomical and morphological characteristics of the aorta and its branches is mandatory. Software that perform three dimensional reformatting of multislice tomographic images, allow for the study of the whole aorto-iliac axis and the perpendicular visualization of the origin of the renal arteries. The correct length of the proximal neck can be evaluated and adequate graft fixation and sealing may be foreseen. A technique is presented, using an software, for the orthogonal correction of the position of the renal arteries in relation to the proximal neck, which may guide the radioscopic orientation intraoperatively. Methods: Within a multiplanar tomographic image reconstruction, virtual triangulation allows for the three dimensional orthogonal correction of the renal arteries' ostia position. The predetermined best angulations for visualization are annotated and used for the positioning of the surgical C-arm. Results/Discussion: Some authors discuss that the anatomic position of the renal vessels seen on the tomographic scan can change during the surgical procedure. It is known that the renal arterys' angular positioning does not alter, even after insertion of stiff guidewires, introducers, and the endograft itself. Therefore, it is possible, using concepts of spacial geometry and orthogonal correction, to predict the ideal bidimensional intraoperative positioning of the radioscopy device in order to reproduce the optimized renal artery ostial projection, ensuring the best accuracy during endograft deployment. Conclusion: As closer to the tomographic reproduction was the radioscopic correction, more careful is the visualization of the ostium of the renal artery, better is the exploitation of the lap for fixing and sealing and the endoprosthesis deployment is more accurate. .