Evaluating a calcium chloride–elastase combination for creating large aneurysms in the endovascular rabbit elastase model

Abstract

Purpose

Large aneurysms have a higher rupture risk, yet no available in vivo animal model consistently produces large aneurysms for testing endovascular therapies. Recent research suggests that adding calcium chloride (CaCl₂) to elastase yields larger aneurysms in a surgical rabbit model. We evaluated whether this effect translates to an endovascular approach by comparing aneurysm sizes created using elastase alone versus a CaCl₂–elastase combination.

Methods

Aneurysms were created in the right common carotid artery of New Zealand rabbits. One group received 1 mL porcine elastase; the other received elastase plus 0.055 g CaCl₂ (0.5 M). After four weeks, patency was confirmed via digital subtraction angiography. Two blinded co-authors measured the neck, width, and height of the aneurysms. Aneurysm volumes were estimated using AngioCalc.com. Statistical analyses were performed using either the Mann–Whitney U-test or t-test based on data distribution.

Results

Twenty-nine (29) New Zealand rabbits were included in the study: six in the CaCl₂ and elastase groups, 23 in the elastase-alone group. All induced aneurysms remained patent at follow-up. Mean neck size was significantly larger in the CaCl₂ + elastase group than in the elastase-alone group (4.4 ± 1.1 mm vs 3.5 ± 0.95 mm; respectively, p = 0.02). Differences in width (4.1 ± 0.92 mm vs 3.4 ± 0.36 mm; p = 0.06), height (9.0 ± 1.1 mm vs 9.1 ± 2.1 mm; p = 0.46), and volume (83.5 ± 38.35 mm^³ vs 53.0 ± 16.94 mm³; p = 0.11) were not significant between CaCl₂ + elastase and elastase-alone, respectively.

Conclusions

CaCl₂ modestly increased neck size but did not significantly enlarge overall aneurysm dimensions. Further studies are needed to assess its utility in endovascular aneurysm models.