Long-term Impact of Carotid Endarterectomy on Choroidal and Choriocapillaris Perfusion: The INFLATE Study

Abstract

Purpose: When performed for clinically significant carotid artery stenosis (CAS), the long-term impact of carotid endarterectomy (CEA) on choroidal and choriocapillaris (CC) circulation was studied using swept-source OCT angiography.

Design: Prospective observational study.

Participants: Patients with clinically significant CAS undergoing unilateral CEA.

Methods: Swept-source OCT angiography scans were performed on both eyes at baseline (before CEA), within 1 week post-CEA (short-term follow-up [FU]), and ≥30 days post-CEA (long-term FU). Using validated algorithms, we measured mean choroidal thickness (MCT), choroidal vascularity index (CVI), choroidal vessel volume (CVV), CC flow deficit percentage (CC FD%), and CC thickness within the 5-mm circle centered on the fovea for both the eye ipsilateral to CEA (surgical side) and the contralateral eye (nonsurgical side). Multivariable regression analysis was conducted to evaluate the impact of baseline demographic and clinical factors on the changes in choroidal and CC parameters.

Main outcome measures: Both the short- and long-term changes in MCT, CVI, CVV, CC FD%, and CC thickness.

Results: The study included 58 eyes from 29 patients. Significant short-term improvements in MCT (P < 0.001) and CC thickness (P = 0.006) were observed post-CEA on the surgical side. Long-term FU showed sustained increases in MCT compared with baseline (P = 0.02), while CC thickness was not significantly different from baseline (P = 0.10). The CVI did not change significantly from baseline at either short-term (P = 0.45) or long-term (P = 0.22) FU on the surgical side. While CVV demonstrated a short-term rise immediately post-CEA (P < 0.001), the difference was not statistically significant at the long-term evaluation (P = 0.06). No significant improvement in CC FD% from baseline was observed at any visit post-CEA (short-term P = 0.81, long-term P = 0.91). The nonsurgical side only showed a significant reduction in CVI at the long-term FU visit compared with before CEA (P = 0.01). Clinical variables such as age, degree of stenosis, diabetes, hypertension, and smoking status did not greatly impact the outcomes.

Conclusions: Unilateral CEA demonstrated a sustained increase in MCT, suggesting persistent improvements in choroidal perfusion in the ipsilateral eye.

Financial disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Keywords: Carotid artery endarterectomy (CEA); Choriocapillaris flow deficits (CC FD); Choriocapillaris thickness; Choroidal vascular index (CVI); Mean choroidal thickness (MCT).

Figure 1

Box plots showing the distribution of MCT (A), CVV (B), and CVI (C) across 3 time points: before CEA, short-term FU, and long-term FU. Red boxes represent the surgical side, while blue boxes correspond to the nonsurgical side, with each measurement taken within a 5-mm circle centered on the fovea. The median value for each parameter is depicted by the central line of the box, and the mean is indicated by the dot. The extremities of the boxes define the first and third quartiles. CEA = carotid endarterectomy; CVI = choroidal vascularity index; CVV = choroidal vessel volume; FU = follow-up; MCT = mean choroidal thickness.

Figure 2

A 78-year-old patient with 80% CAS on the surgical side and 40% CAS on the nonsurgical side that underwent unilateral carotid endarterectomy (CEA) on the ipsilateral surgical side. Columns represent: (1&4) Baseline visit (3 days before CEA); (2&5) short-term FU visit (4 days after CEA); (3&6) long-term FU visit (3.7 months after CEA). Rows represent (A) choroidal thickness (CT) maps; (B) choroidal vascularity index maps; (C) en face choroidal vasculature map; (D) choriocapillaris (CC) thickness maps; (E) CC flow deficits binary maps. On the surgical side, there is a visually significant increase in both CT and CC thickness 4 days after CEA compared with 1 day before CEA (A-2 and D-2); the increase in CT was maintained in the long-term (A-3) while the CC thickness at the long-term visit was comparable to baseline (D-3). On the nonsurgical side, no visually significant changes at the long-term visit compared with before CEA were noted, except for a slight increase in CC thickness (D-6). CAS = carotid artery stenosis; FU = follow-up.

Figure 3

Box plots illustrating the distribution of CC thickness measurements (A) and CC FD% measurements (B) across 3 time points: before CEA, short-term FU, and long-term FU. The surgical side is indicated in red and the nonsurgical side in blue, and each parameter is measured within the 5-mm circle centered on the fovea. The central line of each box marks the median value of CC thickness or CC FD%, and the dot within indicates the mean. Box boundaries represent the first and third quartiles. CC = choriocapillaris; CC FD = choriocapillaris flow deficit; CEA = carotid endarterectomy; FU = follow-up.

Figure 4

An 80-year-old patient with 95% CAS on the surgical side and 20% CAS on the nonsurgical side that underwent unilateral carotid endarterectomy (CEA) on the ipsilateral surgical side. Columns represent: (1&4) Baseline visit (3 days before CEA); (2&5) short-term FU visit (4 days after CEA); and (3&6) long-term FU visit (7.8 months after CEA). Rows represent (A) choroidal thickness (CT) maps; (B) choroidal vascularity index (CVI) maps; (C) en face choroidal vasculature map; (D) choriocapillaris (CC) thickness maps; (E) CC FDs binary maps. On the surgical side, there is a visually significant increase in CT 4 days after CEA compared with 3 days before CEA (A-1 vs. A-2); this increase was slightly reduced at the long-term assessment but was still increased compared with baseline (A-1 vs. A-3). There is an enlargement of choroidal vessels at the short-term FU visible both on the CVI maps (B-2) and on the en face choroidal vasculature maps (C-2). This increase was no longer evident at the long-term assessment (B-3 and C-3). There is also a visually significant increase in CC thickness at the short-term FU visit (D-2). The CC thickness returned to its baseline appearance at the long-term FU visit (D-3). No visually significant changes were noted in the CC FD maps (E-1, E-3). On the nonsurgical side, there was a subtle increase in the CT at the long-term assessment (A-6) compared with previous visits (A-4 and A-5), but no other significant changes at the long-term visit were appreciated when compared with baseline, 3 days before CEA (B-6, D-6). CAS = carotid artery stenosis; CC FD = choriocapillaris flow deficit; FU = follow-up.