Intentional switch between 1.5-mm and 1.25-mm burrs along with switch between rotawire floppy and extra-support for an uncrossable calcified coronary lesion.

Rotational atherectomy (RA) is considered to be the last resort for a severely calcified coronary artery lesion. Severe complications such as vessel perforation or burr entrapment is closely associated with forceful burr manipulation during RA. The instructions for use of Rotablator (Boston Scientific, Marlborough, MA, USA) prohibit forceful burr manipulation when rotational resistance occurs. Nevertheless, RA operators tend to forcefully manipulate the burr if it cannot cross the lesion, because there has been no established strategy for an uncrossable lesion. We present a case with a severely calcified coronary lesion, which was uncrossable by a burr 1.5 mm with RotaWire Floppy (Boston Scientific). We intentionally switched 2 burrs (1.5-mm and 1.25-mm) and 2 RotaWires (Floppy and Extra-support) to cross the lesion. Uniquely, we downsized the burr (from 1.5-mm to 1.25-mm) initially for better penetration force, and upsized the burr (from 1.25-mm to 1.5-mm) finally for better contact to the calcification within the lesion. Our case suggests that 4 different types of combinations might work in a mutually complementary manner for an uncrossable calcified lesion. <Learning Objective: In rotational atherectomy, severe complications such as vessel perforation or burr entrapment are closely associated with forceful burr manipulation. We present a case with a severely calcified coronary lesion, which was uncrossable by a burr 1.5 mm with RotaWire Floppy. We intentionally switched 2 burrs and 2 RotaWires to cross the lesion. Our case suggests that 4 different types of combinations might work in a mutually complementary manner for an uncrossable calcified lesion.>.

Introduction

Rotational atherectomy (RA) is generally considered to be the last resort for a severely calcified coronary artery lesion. However, the incidence of complications such as cardiac tamponade is greater in RA than in conventional percutaneous coronary interventions (PCI) [1]. Moreover, unique complications such as burr entrapment have been observed in RA [2], [3], [4]. Of those complications, severe complications such as vessel perforation or burr entrapment are closely associated with forceful burr manipulation during RA. The instructions for use of Rotablator (Boston Scientific, Marlborough, MA, USA) prohibit forceful burr manipulation when rotational resistance occurs [5]. Nevertheless, RA operators tend to forcefully manipulate the burr if it cannot cross the lesion, because there has been no established strategy for an uncrossable lesion. We present a case with a severely calcified coronary lesion, which was uncrossable by a burr 1.5-mm with RotaWire Floppy (Boston Scientific, Marlborough, MA, USA). We intentionally switched 2 burrs (1.5-mm and 12.5-mm) and 2 RotaWires (RotaWire Floppy and RotaWire Extra-support) for an uncrossable coronary lesion.

Case report

A 69-year-old woman underwent RA of a severely calcified stenosis in the right coronary artery (Fig. 1A). A 7 Fr AL1SH guide catheter was inserted via her right femoral artery. An intravascular ultrasound catheter could not cross the lesion due to severe calcification. We started RA with a 1.5-mm burr and a RotaWire Floppy. Although we performed 5 RA sessions (rotational speed, 180,400 ± 6151 rpm; total duration, 69 s), the 1.5-mm burr did not cross the lesion (Fig. 1B). We switched from a 1.5-mm to a 1.25-mm burr for better penetration force. The 1.25-mm burr advanced a small amount after 4 RA sessions (rotational speed, 190,750 ± 1479 rpm; total duration, 64 s), but still could not cross the lesion (Fig. 1C). We switched from the RotaWire Floppy to the RotaWire Extra-support to obtain a different guidewire bias. Although we performed 4 RA sessions (rotational speed 186,250 ± 5166 rpm, total duration, 76 s), the 1.25-mm burr could not cross the lesion (Fig. 1D). Because the diamond coating of the 1.25-mm burr might not contact the area of calcification, we switched from the 1.25-mm to a 1.5-mm burr to increase the diamond coating area. The 1.5-mm burr along with RotaWire Extra-support successfully crossed the lesion (rotational speed 190,750 ± 1785 rpm; total duration, 51 s) (Fig. 1E). After RA, we used a 2.0 × 20 mm drug-coated balloon and obtained an optimal result (Fig. 1F). The summary of procedures is shown in online Video 1.

Fig. 1

(A) Severely calcified stenosis (arrow heads) in the right coronary artery. (B) A 1.5-mm burr with RotaWire Floppy could not cross the lesion. (C) A 1.25-mm burr with RotaWire Floppy advanced a small amount, but still could not cross the lesion. (D) A 1.25-mm burr with RotaWire Extra-support could not cross the lesion. (E) A 1.5-mm burr with RotaWire Extra-support successfully crossed the lesion. (F) Final angiogram after drug-coated balloon dilatation.

Discussion

The present case shows the usefulness of the intentional switch of 2 burrs and 2 RotaWires. Although the 1.25-mm burr is considered to have greater penetration force than the 1.5-mm burr, the 1.25-mm burr has a smaller diamond coating area. Furthermore, a RotaWire Extrasupport would yield a different guidewire bias from a RotaWire Floppy, which may allow RA burrs to contact the calcified lesion more efficiently. Therefore, 4 different types of combinations may work in a mutually complementary manner for an uncrossable calcified lesion.

Expert consensus reports recommend downsizing of the burr, when the burr cannot cross the lesion after several attempts [6]. Expert consensus reports also recommend the burr 1.5-mm as the default burr size for various lesions [6]. However, the optimal timing of downsizing of the burr has not been described in the literature including expert consensus reports. From our experience, we consider to downsize the burr, when the burr is not moving at all after several sessions in spite of better contact to the calcification (optimal speed reduction such as 3000–5000 rpm). Since we started a burr 1.5-mm, downsizing to a 1.25-mm burr from the 1.5-mm burr should be the first step for the uncrossable lesion. However, there has not been any established strategy after downsizing the burr.

The exchange of RotaWires from Floppy to Extra-support may be an alternative option for the uncrossable lesion [7], although the exchange of RotaWires was not officially recommended. When the burr 1.25-mm with the RotaWire Floppy could not cross the lesion, we considered that the burr 1.25-mm might not contact the calcification within the lesion adequately. If we use the RotaWire Extra-support instead of the RotaWire floppy, a different guidewire bias may help the burr 1.25-mm to contact the calcification within the lesion adequately. Therefore, the exchange from RotaWire Floppy to RotaWire Extra-support would be the second step for the uncrossable lesion. Some operators may prefer to exchange RotaWires before downsizing of the burr, because the cost for an additional RotaWire is much cheaper than that for an additional burr.

The upsizing of the burr may be a unique option for the uncrossable lesion. We previously reported that the burr 1.5-mm could cross the lesion that the burr 1.25-mm could not cross [8]. The burr 1.5-mm has an advantage over 1.25-mm for crossing some calcified lesions, partly because the shape of the burr 1.25-mm is sharper than that of the burr 1.5-mm [8]. Moreover, the diamond coating area is smaller in the 1.25-mm burr than in the 1.5-mm burr, indicating that the burr 1.5-mm may contact the calcification within the lesion more efficiently. Therefore, upsizing to the 1.5-mm burr from the burr 1.25-mm would be the third step for the uncrossable lesion. The optimal timing of upsizing of the burr as well as that of downsizing of the burr has not been described in the literature. From our experience, we consider to upsize of the burr, when the burr is not moving at all after several sessions without optimal speed reduction (typically no speed reduction or 1000 speed reduction). Although we tried 4 different types of combination, each combination played a certain role for the uncrossable lesion. The summary of 3-step approach is shown in Fig. 2.

Fig. 2

The summary of 3-step approach for an uncrossable calcified lesion. Ca, calcification.

Our 3-step approach has a significant advantage over the conventional approach for the uncrossable lesion. Each combination would not require forceful manipulation of the burr, because RA operators tend to push the burr forcefully when there are no alternative options for crossing the lesion. The 3-step approach would help operators to be calm during RA, which should be the most important factor during complex PCI. On the other hand, the 3-step approach has some limitations. First, since the 3-step approach requires 2 burrs and 2 RotaWires, the total cost for RA would be greater in the 3-step approach than in the conventional RA. Although the combination of RotaWire floppy and burr 1.5-mm was used as the default setting in our case, the combination of RotaWires and burrs should be adjusted according to the lesion. If the initial combination of RotaWires and burrs successfully cross the lesion, the total cost would be the lowest. It would be helpful for the selection of appropriate RotaWires to check the conventional guidewire bias before proceeding to RA. Second, the exchange of RotaWires from Floppy to Extra-support requires attention regarding the guidewire bias, which may be associated with vessel perforation during RA [9]. We should not use the RotaWire Extra-support for severely angulated lesions. Therefore, the 3-step approach may be contraindicated for severely angulated lesions. Third, if the third step (the burr 1.5-mm with RotaWire Extra-support) does not work, it would be difficult to cross the lesion by RA. Balloon dilatation following RA may work for such uncrossable lesions if the reason for uncrossing is an angulation within the lesion [10]. An intravascular ultrasound may help operators to decide how they manage the calcified lesion, while it would be difficult to bring the intravascular ultrasound catheter to the uncrossable lesion. It should be important to accept there are cases in which RA is unable to penetrate [6].

In conclusion, intentional switch between 1.5-mm and 1.25-mm burrs along with switch between RotaWire floppy and Extra-support was effective for an uncrossable coronary lesion. Four different types of combinations may work in a mutually complementary manner without sacrificing the safety in RA.

Funding

This work was supported by Grants-in-Aid for Scientific Research (C) (Kenichi Sakakura, JSPS KAKENHI Grant Number 17K09521).

Conflict of interest

Dr Sakakura has received speaking honoraria from Abbott Vascular, Boston Scientific, Medtronic Cardiovascular, Terumo, OrbusNeich, Japan Lifeline, and NIPRO; he has served as a proctor for Rotablator for Boston Scientific; and he has served as a consultant for Abbott Vascular and Boston Scientific. Prof. Fujita has served as a consultant for Mehergen Group Holdings, Inc.