Intravascular Iliac Artery Lithotripsy to Facilitate Aortic Endograft Delivery: Midterm Results of a Dual-Center Experience

Abstract

Purpose: To assess the feasibility and safety of intravascular lithotripsy (IVL) for enabling transfemoral abdominal (EVAR), thoracic (TEVAR), and thoracoabdominal (BEVAR) endovascular aneurysm repair in patients with narrow and calcified iliac arteries.

Materials and methods: Consecutive patients treated with IVL for severe calcified and narrowed iliac access before EVAR, TEVAR, or BEVAR between November 2020 and June 2022 were retrospectively evaluated. All anatomical iliac characteristics were acquired by multi-planar reconstruction of preoperative computed tomography angiography (CTA). The hostility of the vascular accesses was classified based on Peripheral Arterial Calcium Scoring System (PACSS) and calcified access severity score (CASS), a new score considering both anatomical (calcium grade and length, minimum lumen diameter [MLD], and tortuosity index) and aortic stent-graft (SG/MLD index) parameters. Primary endpoint was technical success defined as successful aortic endograft delivery and deployment without iliac rupture. Freedom from complications and primary patency were additionally analyzed.

Results: Twenty-eight iliac axes were treated with IVL (8 bilateral) in 20 patients (mean age 74.5±6.7 years) with a mean follow-up of 26.5±6.2 (range 17-36) months. Ten patients underwent EVAR: 3 TEVAR, and 7 BEVAR procedures. In 14 patients (70%), aneurysm disease was associated with symptomatic aorto-iliac occlusive disease (AIOD), with Rutherford class III to IV. The PACSS was grade IV in 89% of the cases and the CASS (mean 14±2) was grade III to IV in all cases. The stent-graft (SG) outer diameter (5.60±1.65 mm) was significantly larger by 50% than MLD (3.96±1.20 mm), with an SG/MLD index of 1.50±0.51 (p<0.001). Technical success was 100%. No dissection, rupture, or distal embolization occurred. One (3.4%) bail-out stenting was necessary as endoconduit after IVL treatment. One month CTA showed that postoperative luminal gain increased by 93% (p<0.001). An improvement of 2 Rutherford classes occurred in all AIOD patients with a primary patency of 100% at last follow-up.

Conclusions: This study shows the safety and feasibility of IVL as a valuable option to treat narrow and calcified iliac arteries to facilitate endograft delivery. Further studies will be useful to confirm these results.Clinical ImpactIn this article, the use of intravascular iliac artery lithotripsy to facilitate aortic endograft delivery is explored. The presence of iliac severe calcifications still represents a contraindication for aortic endovascular repair. Intravascular lithotripsy increases the feasibility and safety of endovascular aortic procedures, facilitating endograft delivery and reducing the risk of iliac rupture and/or dissections by improving vessel compliance and luminal gain. This novel vessel preparation could be an alternative to "paving and cracking" and/or iliac conduits. This study describes a new score to classify the severity of iliac calcifications, considering anatomical parameters and the profile of aortic endografts delivery system.

Keywords: abdominal endovascular aortic repair; aorto-iliac occlusive disease; calcified iliac; hostile access; iliac conduit; intravascular lithotripsy; large-bore devices; paving and cracking; thoracic endovascular aortic repair; vessel compliance.

Figure 1.

Calcified access severity score (CASS) to assess the severity of hostile access parameters of each iliac axis.

Figure 2.

Flow chart of patients treated by intravascular lithotripsy to facilitate the delivery of aortic endografts in case of hostile calcified iliac access. This protocol is based on a calcified access severity score (CASS, Figure 1). Iliac axis with CASS ≥10 was indicated for Shockwave IVL treatment.

Figure 3.

“ACCESS” case. A and B: Preoperative computed tomography angiography (A), and angiogram (B) of narrowed and calcific iliac axes in case of aortic arch disease (thoracic aortic endograft with 25 French [Fr] outer diameter delivery system). C to E: Pre-intravascular lithotripsy (IVL) angiogram (C), vessel preparation by IVL treatment (D), and post-IVL angiogram (E). F: Delivery of a thoracic aortic endograft with 25 Fr outer diameter. G: Completion angiogram showing no signs of iliac ruptures and/or dissections.

Figure 4.

“Aorto-iliac occlusive disease (AIOD)” case. A: Preoperative computed tomography angiography and duplex-scan. B: Procedure. Preoperative angiogram, vessel preparation by IVL treatment from brachial access, EVAR, iliac kissing covered stenting in place of iliac limbs, right external iliac artery recanalization-IVL-stenting, and completion angiogram. Procedure performed in local anesthesia by using 2 percutaneous access (left brachial and left common femoral). C: Postoperative computed tomography angiography and duplex-scan control on right and left common femoral artery. D: Two years’ duplex-scan control showing stable bi-3 phasic waveforms at the same locations.

Figure 5.

Preoperative and postoperative results. A: Overall, calcified access severity score (CASS) and compared in 2 subgroups, ACCESS and ACCESS+AIOD (aorto-iliac occlusive disease). B: Comparison in millimeters (mm) between preoperative/postoperative minimum lumen diameter and stent-graft outer profile.