The standard of care for embolization of visceral aneurysms has been varied, with little long-term clinical data. Currently, interventionists gauge success by the outcome of post-procedure angiographic images. Still unresolved, however, are the long-term occlusion rates of coil embolization, writes Corey Teigen
Two studies that looked at intracranial aneurysms reported that achieving a packing density over 24– 26% led to better long-term results and fewer re-interventions (Kawanabe Y et al, Acta Neurochirurgica, 2001 and Sluzewski M et al, Radiology, 2004). A different group of investigators in Japan (Yasumoto T et al, Journal of Vascular and Interventional Radiology [JVIR] 2013) then carried out another study looking at the same parameters with regards to visceral aneurysms. These data were published in JVIR in December 2013 and presented at a number of meetings over the past year (2014). The results mirrored that of the neurological studies. Again achieving greater than a 24% packing density led to better long-term occlusion rates and negated the need for re-interventions.
As we reported in JVIR in January 2015, the Aneurysm Coiling Efficiency (ACE) registry offers a unique opportunity to study the demographics and long-term outcomes of a cohort of patients with embolization of the peripheral vasculature using Ruby coils (Penumbra). This is a prospective, multicentre study of patients with intracranial or peripheral aneurysms who were treated with the Ruby coil. Approximately 2,000 patients with intracranial or peripheral aneurysms treated by the Ruby coil at up to 100 centres were enrolled. Collection of long-term follow-up data (procedure through 12 months) is conducted in accordance to the standard of care at each participating centre. Additionally, the study looked at radiation time and the number of devices needed to treat occlusions of aneurysms, arteriovenous malformations, and vessel sacrifices.
Penumbra has made significant advancements in coil technology both in the neurovasculature as well as in the peripheral anatomy. Ruby coils are the largest calibre and longest devices available on the market. By offering lengths that are up to three times longer than other approved coils, while being the softest and easiest to deploy, these coils allow for efficient embolization while achieving a higher packing density. As a detachable coil, it allows physicians to deploy and retrieve 100% of the devices with unlimited working time. The compatibility with large lumen microcatheters (.025–027”) and multiple softness options allow the coil to be delivered anywhere you can track a microcatheter.
We compiled data from the ACE registry from March 2012 to January 2015 at 13 centres. The first 68 cases comprised of seven splenic, 11 renal, three mesenteric, one hepatic, and one iliac artery aneurysms. In addition, there were seven arteriovenous malformations, six fistulae, four varices, and 28 vessel sacrifices treated with the Ruby coils.
We found that aneurysms detected at the splenic, renal, mesenteric, hepatic, and iliac arteries had volumes from 110–21,500mm3 and neck diameters 3–16mm. The median number of coils placed per aneurysm/malformation was six (n=40), with a mean packing density of 28% and mean fluoroscopy time of 28 minutes. No procedural serious adverse events were observed.
Our results showed that the post-treatment distribution of Raymond aneurysm occlusion classification scores were class I occlusion (91.3%), class II occlusion (4.3%), and class III occlusion (4.3%). Patients with six-month follow-up data revealed class I complete occlusion (92.9%) and class II occlusion (7.1%). Of the 28 peripheral vessel sacrifices, 100% were reported to have had successful coil embolization by the treating physician. Thirteen patients at the six-month follow-up CT assessments revealed stable or progressive occlusion. No procedural serious adverse events were observed. The median number of coils placed was 2.5 and mean fluoroscopy time was 21 minutes.
The new POD device from Penumbra was not included in the ACE registry. Going forward, more data will be needed to determine the true importance of packing density in visceral aneurysms but also in areas like pulmonary arteriovenous malformations, bleeds, and other lesions where stable long-term occlusion is crucial.
Corey Teigen is chairman of the Interventional Radiology Department at Sanford Health Fargo, North Dakota, USA. He is a consultant to Penumbra