THE ENDURANT STENT GRAFT IN HOSTILE ANEURYSM NECK ANATOMY

Transcription

1 THE ENDURANT STENT GRAFT IN HOSTILE ANEURYSM NECK ANATOMY Patrice Mwipatayi FCS (SA), MMed, FRACS Professor of Vascular surgery Royal Perth Hospital, University of Western Australia, Perth, WA Co-Authors: Vikram Vijayan MRCS, FRCS

2 Conflict of Interest PI FOR ENGAGE REGISTRY (MEDTRONIC) PERTH

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4 Excessive oversizing may produce a guttering effect at the graft-aortic sealing zone, increasing the risk of Type I endoleak, distal migration, and aortic neck dilatation.

5 Aneurysm Neck Shapes

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7 REVERSE TAPER CONFIGURATION: The lower portion of the neck is significantly larger than the upper portion of the neck at the proximal attachment site. Schematic representation of a flared neck, which is defined as an increase in the proximal diameter 2 mm over a distance of 5 mm distal to the most caudal renal artery. X is the maximum diameter of the aortic neck just caudal to the lowest renal artery

8 In geometry, a frustum is the portion of a solid that lies between two parallel planes cutting it. In the aerospace industry, frustum is the common term for the fairing between two stages of a multistage rocket (such as the Saturn V), which is shaped like a truncated cone.

9 Schematic diagram and formula for the calculation of the volume of a frustum, which is the truncated portion of a solid cone that is left after cutting off a top section with a plane parallel to the base. To calculate its volume, the proximal aortic neck was assumed to be geometrically similar to a frustum.

10 15 mm 2 mm 8 mm Excessive oversizing may produce a guttering effect at the graft-aortic sealing zone, increasing the risk of Type I endoleak, distal migration, and aortic neck dilatation.

11 METHOD We conducted a prospective observational study of consecutive patients undergoing endovascular repair using the Endurant stent-graft from December 2008 to September 2011 at two hospitals in Western Australia, Royal Perth Hospital and Hollywood Private Hospital Mean duration of follow-up was 36 months (48-60 Months). 98% patients had at least one postoperative clinical evaluation, AXR and CTA or abdominal ultrasound and 90% have reached at least 2-year follow-up (1-year). Mwipatayi et al. J Endovasc Ther. 2013;20:

12 RESULTS 73 patients (male 92%, mean age of 75 years) underwent EVAR using the Endurant stent-graft during the study period. Mean AAA size was 57±10 (SD) mm, with a mean proximal neck length of 33.3±10 mm and a mean infrarenal neck angulation of 25 ±15. Nearly 40% were deemed either outside the IFU based on the proximal neck anatomy (12.3%) or had a flared neck (30%) Mwipatayi et al. J Endovasc Ther. 2013;20:

13 Indication For Use (IFU)

14 Demographic data and pre-operative risk factors in three groups Mwipatayi et al. J Endovasc Ther. 2013;20:

15 Pre-operative morphological assessment of aaa and perioperative data in the three groups Mwipatayi et al. J Endovasc Ther. 2013;20:

16 Proximal neck anatomy compared to proximal endurant stent graft-graft dimensions

17 FOLLOW-UP / STANDARD NECK Available for the 1 st year in 42 OF 44 PATIENTS 4 Patients with type 2 endoleak Coiling in one patient 1 Limb Occlusion: Cross-over bypass graft 2 Late deaths (not AAA related)

18 FOLLOW-UP / OUT OF IFU NO ENDOLEAK OR GRAFT COMPLICATION NO SECONDARY PROCEDURES IN FIRST YEAR 1 DEATH WITHIN 3 MONTHS (non-aaa related)

19 FOLLOW-UP / FLARED PROXIMAL NECK 5 Type 2 endoleak with 2 successfully IMA embolised 1 Limb Occlusion: Cross-Over bypass graft 1 Death at 30 days follow-up 1 Death at 6 months follow-up

20 CONCLUSION Early and Midterm outcomes indicate that the endograft may be utilized with acceptable results in patients with reverse taper necks as long as there is adequate oversizing of the graft Although generally accepted guidelines certainly exist, one must use excellent judgment to realize a compromise between extremely rigorous inclusion criteria that would exclude a large number of patients. Frustum theory can be used pre-operative anatomical assessment and for future graft design (graft design with a flared first stents for adequate volumetric sizing).