We demonstrated the feasibility of EVT for CFA with severe calcified plaques using direct puncture of a metal needle. In this case, we were able to pass through the center of the calcified plaque and obtain sufficient initial lumen gain after balloon angioplasty by a simple method. Obtaining the initial lumen area is difficult if severe calcified lesions are present. Especially in the case of eccentric calcified nodules, not only does an open lumen not spread sufficiently, but excessive balloon dilation also involves the risk of vascular perforation. There has been a report on the feasibility of atherectomy devices (Stavroulakis et al. 2018). However, there is also the problem that these devices cannot be used in some areas for the reason that medical insurance does not cover them.
Passing the guidewire through heavy calcification is often difficult. Our method appears to be a simple and easy method of piercing a lesion with a metal needle and modifying the lesion. In the EVT field, methods using a metal needle, such as the PIERCE technique, and inner PIERCE technique for patients in whom there is difficulty in passing a balloon, have been reported (Ichihashi et al. 2014; Nakama et al. 2020). Metal needles are much harder and sharper than guidewires, and therefore, they can penetrate even with severe calcification. Our method is primarily to use a metal needle instead of guidewires to allow severe calcification to pass directly. Our method can also help subsequent balloon passage by modifying the lesion from intravessels, as well as passage of calcification.
We usually use a scoring balloon or cutting balloon after guidewire passage combined with high-pressure balloons.
Surgical endarterectomy appears to be a gold standard treatment for calcified CFA lesions. However, we consider that our method can be indicated for cases in which EVT should be chosen because of problems, such as the general condition and comorbidities. Additionally, our method can be indicated in cases in which performing EVT appears to be preferable for aortoiliac lesions and femoropopliteal lesions at the same time as CFA disease.
As a possible complication, the possibility of distal embolism cannot be ruled out because calcification expands while being crushed. Therefore, we usually try to place a filter wire (Parachute® filter wire; Keisei Medical, Tokyo, Japan) in the popliteal artery after passing the anterograde guidewire. Fortunately, we have not experienced any clinically problematic distal embolism. We always insert a guidewire into the antegrade guiding sheath to make the wire externalized. This procedure reduces the risk that the guidewire will be under tension and the needle will get caught. Enlarging the fluoroscopic image and attempting to proceed slowly at the beginning as much as possible are also important to avoid complications. Advancing carefully with the metal needle and guide wire as coaxially as possible is also recommended.
In our case, the initial success of the procedure and good short-term prognosis were confirmed, but the long-term patency is still unclear. A much larger study is required to confirm the safety and efficacy of our method. This procedure appears to be difficult to perform if the calcified plaques are continuous to the SFA and not just in the CFA, or if the SFA is completely occluded from just proximally. In such cases, a metal needle may be inserted directly from the distal part of the occluded CFA, only the CFA may pass through the calcified plaque by metal needle, and the remaining lesions may be passed through according to standard procedures. Even when the CFA to the external iliac artery (EIA) is continuously occluded, applying this technique appears to be difficult because the EIA has considerable bending and it is difficult to pass through it only with a needle. Additionally, applying this method to the ipsilateral up to the proximal SFA is possible. However, adapting to the direction of the mid-SFA or popliteal artery owing to the problem of needle length and angle is difficult. Although this technique may be applied to more peripheral arteries such as the dorsalis pedis artery, it seems that it is more difficult to pass the lesion by needle alone than CFA because of the small vessel diameter. To the best of our knowledge, this technique has not been previously reported. Therefore, more cases need to be accumulated and the efficacy and safety of this procedure need to be verified.