Wire bias modification with reverse orbital atherectomy for safer rotational atherectomy in calcified bifurcation

Abstract

Although debulking devices are very useful in modifying calcified plaques, their effectiveness is highly dependent on wire bias. In particular, in eccentric calcified bifurcation lesions, wire bias tends to be poor and needs to be corrected for adequate lesion preparation. A 67-year-old man was diagnosed with exertional angina pectoris. Coronary angiography showed a highly calcified eccentric lesion from the left main trunk to the left anterior descending artery. The patient refused coronary artery bypass surgery, therefore we decided to treat this complex bifurcation lesion with percutaneous coronary intervention. Initially, we performed reverse orbital atherectomy (OA) and sifted the guide wire position into the calcified plaque successfully. We continued with rotational atherectomy (RA) using a 2.0 mm burr and were able to obtain sufficient lumen without complications. Finally, the lesion was dilated with a cutting balloon and a drug-coated balloon to obtain a stent-like result. This case demonstrates that wire bias modification with reverse OA enables us to perform more aggressive and effective RA safely in eccentric calcified bifurcation lesions. This combination atherectomy can become an attractive approach in eccentric calcified bifurcation lesions.

Learning objective

Atherectomy devices are helpful for lesion modification in calcified lesions but their effectiveness is highly dependent on wire bias. If the wire bias can be intentionally moved to an optimal position, it can be a very effective procedure in the treatment of calcified lesions. Wire bias modification by reverse ablation with orbital atherectomy that we have demonstrated enables subsequent aggressive rotational atherectomy and this combination atherectomy can be an attractive approach in eccentric calcified lesions.

Introduction

Rotational atherectomy (RA) and orbital atherectomy (OA) are helpful devices that can modify calcified plaques [1]. Still, their effectiveness is highly dependent on the position of the guidewire relative to the lesion, which we call wire bias. In eccentric calcified bifurcation lesions, wire bias tends to be poor and needs to be modified for adequate lesion preparation. This case demonstrates that wire bias modification by reverse ablation with OA is useful for safer and more effective RA in eccentric calcified bifurcation lesions.

Case report

A 67-year-old man underwent cardiac catheterization at another hospital to investigate chest discomfort on exertion, which revealed a highly calcified lesion from the left main trunk (LMT) to the left anterior descending artery (LAD). Although the previous physician strongly recommended coronary artery bypass surgery, the patient refused and was referred to our affiliated hospital for percutaneous coronary intervention (PCI). The patient had been treated for hypertension, diabetes, and dyslipidemia for more than 15 years. In addition, drug-eluting stents (DES) were placed in his LAD and right coronary artery (RCA) 10 years previously. Although coronary angiography showed no significant stenosis in the RCA, there was severe stenosis with heavy calcification from the LMT to the proximal LAD and in-stent restenosis in the middle of the LAD. In addition, there was severe stenosis in the distal part of the left circumflex artery (LCX) (Fig. 1A, B).

Fig. 1.

Baseline and final angiogram. Baseline angiogram (A, B) showed multivessel disease, including a severely calcified lesion from the distal left main trunk to the proximal left anterior descending artery (LAD) (white arrowhead), in-stent restenosis in the middle LAD (blue arrowhead), and severe stenosis in the distal left circumflex artery (yellow arrowhead). The final angiogram (C, D) showed satisfactory results of the LAD after drug-coated balloon angioplasty (white arrowhead).

We decided to perform PCI to the LMT to the proximal LAD and the mid LAD. The treatment was performed via the right common femoral artery with an 8-F guiding catheter (SPB3.5SH; ASAHI Intec, Nagoya, Japan). A guidewire (SION Blue; ASAHI Intec) was passed through the stenosis and the lesion was observed with optical frequency domain imaging (OFDI) (Terumo Corporation, Tokyo, Japan) before the treatment. OFDI revealed eccentric, severely calcified lesions on the opposite side of LCX and the diagonal branch (Fig. 2A). At first, we performed reverse ablation with Diamondback 360® coronary orbital atherectomy system (Cardiovascular Systems, Inc., St. Paul, MN, USA) by pulling the device from the distal to the proximal part of the lesion because the use of RA in this wire bias seemed to be at risk of coronary perforation. Reverse ablation with OA was performed eight times at low rotational speed (80,000 rpm) and four times at high rotational speed (120,000 rpm). OFDI showed that a new groove was created into the calcified plaque (Fig. 2B) and that the guidewire moved away from the contralateral wall. Since the position of the guidewire seemed safe enough to perform more aggressive debulking, we performed RA using a 2.0 mm RotaPro (Boston Scientific Corporation, Marlborough, MA, USA) at 200,000 rpm. Subsequently, OFDI showed deeper groove formation inside the calcified lesion without coronary perforation (Fig. 2C). After applying an additional high-pressure cutting balloon dilation (2.75/10 mm for the proximal LAD and 3.0/10 mm for the LMT, (Boston Scientific)), OFDI confirmed satisfactory luminal gain without major dissections and clear cracks (Fig. 2D).

Fig. 2.

Changes in the angiogram and optical frequency domain imaging (OFDI) at minimal lumen diameter site (upper circle) and bifurcation of the diagonal branch (lower circle) during the procedure. (A) OFDI showed eccentric, severely calcified lesions on the opposite side of the diagonal branch (white arrowhead.). D1, first diagonal branch. (B) Post orbital atherectomy (OA); OFDI showed a new groove was created and the guidewire moved to a safer position in the calcified lesion (blue arrowhead). (C) Post rotational atherectomy (RA); A much larger lumen area was gained by RotaPro with a 2.0 mm burr (yellow arrowhead). (D) Post-cutting balloon; OFDI confirmed satisfactory luminal gain without major dissections.

For the mid LAD lesion, we performed RA with a 1.5 mm RotaPro and dilated with a 2.5 mm cutting balloon. Finally, we were able to dilate the lesion with a drug-coated balloon [SeQuent Please NEO drug-coated balloon (2.5/30 mm for the mid LAD, 2.75/15 mm for the proximal LAD, and 3.5/10 mm for the LMT), B. Braun, Melsungen, Germany] and complete the procedure without a stent.

The final angiogram showed a good result with a thrombolysis in myocardial infarction 3 flow without any signs of complications (Fig. 1C, D). The patient was discharged home on the second day without complications.

Discussion

Although clinical outcomes with PCI have improved dramatically since the introduction of DES, there are still some conditions where the benefits of DES have not been fully realized. Calcified lesions are a typical example, and inadequate lesion preparation has been cited as one of the causes.

RA and OA are helpful devices that can modify calcified plaques [1]. Still, they are not necessarily effective in all calcified lesions because the effectiveness of these devices depends on the position of the guidewire relative to the lesion, which we call “wire bias”. If the wire bias is appropriate, safe and effective ablation can be achieved in the lesion. If the wire bias is not correct, not only the ablation effect is inadequate, but there is also a risk of coronary perforation [2]. In eccentric calcified bifurcation lesions, calcified plaques are usually contralateral to the carina [3] and the guidewire often approaches the healthy vessel wall on the carina side, resulting in poor wire bias (Fig. 3A). Furthermore, because RA is a device that ablates calcified plaques by pushing the device forward, the procedure can contribute to improper wire bias that moves the guidewire away from the lesion and closer to the contralateral vessel wall (Fig. 3B). RA, in this situation, has a high potential for damage to the vessel wall, and the wire bias must be modified to perform the procedure safely.

Fig. 3.

Schema of the wire bias by rotational atherectomy (RA) and orbital atherectomy (OA).

(A) Position of the guidewire before the procedure.

(B) Forward ablation with RA may damage the non-calcified vessel wall because of the wire shift to the carina side.

(C) Reverse ablation with OA can ablate calcified lesions without vessel injury and the guidewire shifts towards the calcified plaque.

We have reported the effectiveness of a combination atherectomy of OA and RA for severely calcified nodules [4], and this combination atherectomy is potentially useful for the preparation of eccentric calcified lesions. Reverse ablation with OA, which ablates calcified plaques by pulling the device from the distal to the proximal part of the bifurcation lesion, can contribute to proper wire bias that moves the guidewire into the calcified plaque without the risk of injuring the contralateral vessel wall (Fig. 3C). We call it “wire bias modification” and it enables additional, more aggressive ablation with RA safely and satisfactory lesion preparation.

With ROTAWIRE Extra support (Boston Scientific Corporation), it may be possible to safely perform RA with a smaller burr. However, we thought that RA with a small burr would not provide sufficient wire bias modification to perform RA with a larger burr, so we attempted to shift the wire bias into the calcified plaque by reverse ablation with OA.

It may be possible to obtain sufficient lumen by continuing to use OA in high-speed mode, but as we have shown in Fig. 2B, the lumen obtained with OA is oval and the thickness of the residual calcified plaque will vary. Even if a cutting balloon is applied in this situation, it may not be effective enough against the remaining calcified plaque, and stent expansion may be inadequate. On the other hand, with RA, we can ablate calcified plaque to a relatively uniform thickness, which allows the cutting balloon to make multiple cracks, resulting in good stent expansion. In a study comparing the two modalities with optical coherence tomography, RA had a significantly larger atherectomy area and greater stent expansion than OA [5]. Therefore, once the wire bias modification was achieved, we performed RA with a larger burr and did not continue with OA.

There are several limitations to applying the combination atherectomy of OA and RA. To perform reverse ablation with OA, the crown of OA must pass through the lesion. If OA does not pass, pre-dilation with a small-sized balloon catheter may be effective. Additionally, it may cost more than completing OA alone or using two different-sized Rota burrs in some countries because we must use two different types of ablation devices.

In conclusion, wire bias modification by reverse ablation with OA and subsequent aggressive RA can become an attractive approach in eccentric calcified lesions.

Consent statement

Witten informed consent was obtained from the patient for publication of this report, including accompanying images.

Conflict of interest

The authors declare that there is no conflict of interest.