From behind the iron curtain to world-wide practice: A review of the history and current status of endovascular abdominal aortic aneurysm repair

Endovascular Aortic Aneurysm Repair is defined as treating of an abdominal aortic aneurysm (AAA) by placing of stent graft device (Endoprosthesis) over guide wires under imaging inside the aneurysmal aorta, with the aim of achieving secure fixation and sealing at a non-diseased proximal and distal landing zones, excluding the aneurysmal segment(s), and thereby abolishing sac pressurization. Dr. Nicholas Volodos from Kharkov, Soviet Union developed the first aortic endograft as an alternative to open repair of AAA which entailed a high morbidity and complications burden, especially in fragile patients. He experimented on dogs in 1970s-'80s using a fabric covered Z-stents. The first human implantation took place in 1985 to treat iliac artery stenosis. He performed his first aortic case on the 24th of March 1987 to treat a post-traumatic thoracic aortic aneurysm. In 1987, Dr. Volodos and his group performed the world's first EVAR procedure for treatment of AAA in Kharkov The first EVAR grafts used took the shape of simple aortic tube grafts stitched to a balloon expandable stent. Initial problems with distal sealing, due to progression of the aneurysmal process in the distal aorta, resulted in a high long term failure rate. This led to the development of devices to fit into the iliac vessels and allow a more secure distal seal. The EVAR system consists of three main components; Delivery system, metal framework, and graft fabric. To facilitate deployment of the stent-graft inside the aorta, devices have evolved from uni-modular to multi modular designs. This allows for easier building of bifurcated devices within the aneurysmal sac. It started with single Aorto-aortic tube graft, to Aorto-uniiliac stent-grafts (AUI) that extend from the aorta into one iliac system, then the bifurcated or Aorto-Biiliac systems that could have uni, bi or even tri-modular design according to the number of the required pieces. The main factors that determine the feasibility of performing an EVAR for a given AAA are clinical and anatomical factors. Patients have to have reasonable quality of life and reasonable mobility before deciding to proceed with such an intervention. Three-dimensional volumetric reconstruction of the Computed tomographic angiography (CTA) images is the benchmark for pre-operative planning of EVAR. As mentioned before, anatomical factors are the key determinants of possibility, and expected difficulty of performing an EVAR for any given AAA. Although Randomised controlled studies (RCTs) have failed to prove statistically significant long term benefits of EVAR over open surgical repair (OSR,) it persistently showed obvious trend towards lesser incidence of perioperative mortality and morbidity rates with EVAR. These merits are more evident when performing this procedure under local anesthetic with a mortality rate as low as 1.6% and total complication rate less than 5%.