The effect of calcium circumference, thickness, and length on the early and late outcomes of transcarotid artery revascularization.

BACKGROUND

Transcarotid artery revascularizationTCAR) has been proposed as an alternative for both transfemoral carotid artery stenting and carotid endarterectomy. Transfemoral carotid artery stenting has been associated with increased risk in heavily calcified lesions. Therefore, this study analyzed the effect of calcium burden (percentage of circumference calcification, thickness, and/or length) on TCAR early and late clinical outcomes.

METHODS

This retrospective review prospectively collected data from patients who underwent TCAR and were enrolled in the TCAR Surveillance Project (Society for Vascular Surgery/Vascular Quality Initiative) at our institution. Preoperative computed tomography angiographies were reviewed to determine three calcium variables: (1) degree of circumferential calcification, classified into 0 to <25%, ≥25% to <50%, ≥50% to <75%, and ≥75%; (2) calcification thickness in millimeters (measured as the greatest thickness); and (3) lesion calcification length in millimeters. The primary outcome was 30-day perioperative stroke/death rate, and the secondary outcomes included the combined 30-day stroke, death, and myocardial infarction rate. Late outcomes included the stroke/death rate and late in-stent restenosis (>50% or >80%). A Kaplan-Meier analysis was used to estimate freedom of stroke, stroke and death, and ≥50% restenosis rates according to calcium classification.

RESULTS

This study analyzed 304 patients (313 procedures) with a mean age of 71 years and mean follow-up of 29.4 months (range, 1-108 months). Circumference calcification were 0% to 25% in 37%, 26% to 50% in 24%, 51% to75% in 18%, and >75% in 20% (0%-50% in 62% and 51%-100% in 38%). Calcification thickness of ≤1 mm was noted in 22%, 1 to 2 mm in 27%, 2 to 3 mm in 26%, 3 to 4 mm in 18%, and >4 mm in 7% (<2 mm in 49% and ≥2 mm in 51%), and a calcification length of <5 mm in 10%, 5 to <10 mm in 4%, 10 to <15 mm in 15%, 15 to <20 mm in 20%, 20 to <25 mm in 26%, and ≥25 mm in 24% (<20 mm in 50%, and ≥20 mm in 50%). The overall 30-day perioperative stroke rate was 2.0% and stroke/death/myocardial infarction of 3.5%. The 30-day perioperative stroke rate according to calcium circumference (<50% vs ≥50%) was 1.7% vs 2.9% (P = .674); length (<20 mm vs ≥20 mm) was 2.1% vs 2.2% (P = 1); and thickness (<2 mm vs ≥2 mm) was 1.5% vs 2.9% (P = .6841). Stroke rates (early and late) stratified between those with a calcium circumference of <50% vs ≥50% were 4.2% vs 4.9% (P = .771); in those with a length of <20 mm vs ≥20 mm, rates were 6% vs 3% (P = .242); and in those with a thickness of <2 mm vs ≥2 mm, rates were 3.8% vs 5.2% (P = .599). Rates for >50% restenosis for calcium circumference (<50% vs ≥50%) were 7.9% vs 8.8% (P = .821); length (<20 mm vs ≥20 mm) were 7.5% vs 9.0% (P = .663); and thickness (<2 mm vs ≥2 mm) were 7.6% vs 8.8% (P = .825). Kaplan-Meier analysis showed that the rates of freedom from stroke, stroke and death, and ≥50% restenosis at 1, 2, and 3 years according to calcification circumference, thickness, and length were similar.

CONCLUSIONS

This study showed no significant effect of calcium burden on TCAR early and late outcomes.