The highlight of the current study is that the primary patency of calcified lesions with BR was significantly lower than that without BR. In addition to BR, lesion length and scaffold use were associated with the primary patency of femoropopliteal lesions with calcifications.
Generally, the higher the calcification score (which considers both area and density of lesion calcification) on CT, the higher the visibility of calcification on angiography; therefore, higher-density calcifications are more likely to be recognized as BR [8–10]. Reportedly, the higher the calcification score evaluated using CT, the higher the restenosis rate after revascularization [5, 11]. The clinical outcomes of EVT for calcified lesions with BR appear to be poor.
The first reason BR is considered a predictor of restenosis is that sufficient dilatation of the lesion was not achieved. In fact, post%DS was significantly higher in the BR (+) group. To overcome this, it seems necessary to use devices that can perform lesion modification such as JETSTREAM, orbital atherectomy, SilverHawk/TurboHawk, and lithotripsy balloon [12–15]. Furthermore, it may be effective to use the ARCADIA technique, which involves guidewire passage through the calcified mass and performing balloon dilatation from the inside [16]. In other words, if sufficient vessel dilatation can be obtained by performing lesion modification in some ways, this may improve clinical results.
Second, patients with dense calcifications such as BR may have advanced arteriosclerosis. The density of coronary artery calcification is related to coronary heart disease and atherosclerotic cardiovascular disease [17, 18]. In summary, the existence of BR itself may be related to its poor clinical outcomes.
In the current study, scaffold use and lesion length remained predictors of restenosis. In calcified lesions, it is not easy to obtain sufficient dilatation, suppress vessel recoil, and prevent drug penetration. Therefore, it is difficult to expect clinical results even if a drug-coated balloon (DCB) and percutaneous transluminal angioplasty are used [14, 19, 20]. Fenelli et al. reported that the greater the angle of the calcification arc, the lower the patency after DCB angioplasty [19]. Therefore, it is better to use scaffolds for calcified lesions to achieve primary patency. Additionally, in lesions with BR, lesion expansion is not expected to be sufficient even if a scaffold is used. It may be necessary to perform lesion modification firmly as described above or to use the “pave-and-crack” technique: a Viabahn stent graft was implanted to “pave” the lesion and protect from vessel rupture, as aggressive predilatation continued until the calcified plaque was “cracked” before lining the entire lesion with a Supera stent [21]. In particular, in long lesions with BR, satisfactory clinical outcomes can hardly be expected, and it can be expressed as a lesion that is not suitable for EVT in the first place. Therefore, surgical reconstruction should be considered [22].
Limitations
The current study has some limitations. First, no atherectomy device was used. Second, the rate of interwoven nitinol stent or stent graft use was very low. Third, the choice of the final device depended on the operator’s decision. Finally, the appearance of calcification may differ between facilities.