Development in techniques and technologies has contributed to the improved procedural success rate in CTO PCI including the crossing of extremely extensive lesions. However, some advanced techniques—such as the retrograde approach, IVUS-guided wiring, and antegrade dissection reentry—involve subintimal wire advancement and result in placing longer stents to cover the entire dissected area. This raises crucial concerns about a higher likelihood of in-stent restenosis, which may affect long-term outcomes. While occlusion length is obviously the decisive factor for the required length of stents, the impact of other clinical, anatomical, and procedural factors has yet to be elucidated. 

We retrospectively enrolled 117 consecutive CTO cases who were successfully treated with PCI between October 2019 and December 2022. Total stent length was defined as the total sum of the placed stents and divided by the occlusion length measured with preprocedural CT angiography to calculate relative stent length (RSL). We compared RSL according to each variable in the complexity scores (J-CTO, PROGRESS-CTO, CT-RECTOR score). Multiple regression analysis was performed to identify the independent factors which contribute to greater RSL. 

Total stent length significantly correlated with CT occlusion length (r=0.32, 95% CI[0.15 – 0.47], p<0.001). We saw significantly smaller RSL in the presence of multiple occlusions on CT angiography (3.08 ± 2.25 vs. 4.19 ± 2.96; p=0.03). When the CTO lesion was successfully crossed using only antegrade wire-escalation strategy, it contributed to smaller RSL (2.65 ± 1.42 vs. 4.12 ± 2.98; p<0.01). Multivariate analysis revealed that lesion crossing with IVUS-guided wiring (tip-detection method) was the independent factor of greater RSL (β=1.87, SE=0.67; p<0.01), while the retrograde crossing did not significantly affect it (β=1.12, SE=0.77; p=0.14). However, direct comparison between IVUS-guided and the retrograde strategies did not differ significantly (4.26 ± 3.30 vs. 3.89 ± 2.39; p=0.57).

Even if the extensively diseased lesions have to be treated, long stent placement can be avoided when CTOs have multiple occlusions and islands. Successful lesion crossing with antegrade wire-based strategies can minimize the required length of stents. While IVUS-guided wiring might  evoke the need for long lesion coverage with multiple stents (due to the enlarged subintimal space created by  the insertion of IVUS catheter), there is no significant difference between IVUS-guided and the retrograde approach in the challenging settings where either of the two strategies is inevitable.