Indian Journal of Vascular and Endovascular Surgery

REVIEW ARTICLE
Year
: 2021  |  Volume : 8  |  Issue : 4  |  Page : 306--309

HawkOne directional atherectomy for infra-inguinal arteries: A review of technique, tips, tricks and contemporary literature


Gurkirat Singh1, Omar Aziz1, Arvind Dhas Lee2,  
1 Department of Vascular Surgery, Nepean Hospital, Penrith, NSW, Australia
2 Department of Vascular Surgery, Nepean Hospital; Department of Vascular Surgery, Nepean Clinical School, Nepean Hospital, University of Sydney, Penrith, NSW, Australia

Correspondence Address:
Gurkirat Singh
Department of Vascular Surgery, Nepean Hospital, Penrith, NSW
Australia

Abstract

This review aims to explore the HawkOne atherectomy (Medtronic), a single use directional atherectomy device, explaining in depth its indication, selection, preparation and application. It further provides techniques and tips to troubleshoot the device upon its use. Further, a review of the current evidence for directional atherectomy in the infra-inguinal arteries is conducted. Identifying that directional atherectomy in the infra-inguinal arteries allow for significant plaque modification and lumen gain without the use of barotrauma from balloon angioplasty. Highlighting that directional atherectomy had a lower incidence of flow limiting dissections and need for stenting after such treatment.



How to cite this article:
Singh G, Aziz O, Lee AD. HawkOne directional atherectomy for infra-inguinal arteries: A review of technique, tips, tricks and contemporary literature.Indian J Vasc Endovasc Surg 2021;8:306-309


How to cite this URL:
Singh G, Aziz O, Lee AD. HawkOne directional atherectomy for infra-inguinal arteries: A review of technique, tips, tricks and contemporary literature. Indian J Vasc Endovasc Surg [serial online] 2021 [cited 2022 Jan 25 ];8:306-309
Available from: https://www.indjvascsurg.org/text.asp?2021/8/4/306/332057


Full Text



 Aim



The HawkOne Atherectomy device (Medtronic) is a single-use system designed to perform directional atherectomy in the femoropopliteal and tibial vessels. This paper will provide a detailed guide on the use of the device including device selection, preparation, usage, and troubleshooting. The paper includes a review of the current evidence for use of directional atherectomy in the infra-inguinal arteries.

 Overview



The HawkOne Atherectomy device is the newest iteration of Medtronic's family of directional atherectomy devices which include the SilverHawk and Turbohawk devices. The HawkOne system consists of a separately packaged cutter driver and 4 different catheter types called LX, LS, M and S. The LX and LS catheters are 7 Fr sheath compatible and the M and S are 6 Fr sheath compatible. All catheters are shaped with a distal curvature (jog) which allows the cutting blade to engage with the vessel wall [Figure 1]. The distal end of the device past the jog, has a rotatable nose cone most distally, followed by an inner lumen into which the cut plaque is packed and finally the cutter window [Figure 2]. The length of the distal tip arrangement (from the cutter to the nose cone) varies from 9.6 cm for the LX device to 5.9 cm for the M and S devices. The LX and LS share the same cutter size but the LS has a distal tip length of 6.6 cm, which means the lesser capacity to pack cut plaque. The cutter driver (handle) houses the battery-operated device driver and 2 switches [Figure 3]. There is an on/off power switch at the back of the handle and a large orange slider switch on the top. When the power switch is on and the slider pulled back to the on position, the cutter is turned on and exposed at the cutter window distally. When the power switch is on and the slider pushed forward to the off position, the cutter is turned off and is no longer exposed at the cutter window. Moving the slider forward to the off position, also causes the cut plaque to be packed into the distal inner lumen. There is a preloaded distal flushing tool which makes preparation and cleaning easier than the previous iterations.{Figure 1}{Figure 2}{Figure 3}

 Indications and Device Selection



HawkOne directional atherectomy is indicated in the femoro-popliteal and tibial arteries. It can be used on both native and previously stented arteries. The directional nature of the device allows for targeted atherectomy of eccentric plaques. In general, the LX and LS devices are chosen to treat the common and superficial femoral arteries. They have the largest crossing profile and can treat vessels between 3.5 and 7 mm in size. The LX has a longer nose cone and this may impede its ability to treat lesions close to the location of an embolic protection device. In such a situation, the LS device may be used. However, because it has a longer nose cone, more plaque can be packed into the LX device before the need for it to be removed for cleaning.

The M device is used for vessels between 3 and 7 mm. It has a smaller cutter and lower crossing profile than the LX and LS devices. The depth of cut is smaller and the resultant lumen gain less. The S device is indicated for arteries between 2 and 4 mm. In general, this is used in tibial arteries.

Embolic protection is highly recommended as distal embolization rates between 3.8% and 6% have been reported.[1],[2] In our center, we use the SpiderFX (Medtronic) filter. In comparison to the Nav6 Emboshield filter (Abbott), the SpiderFX has a smaller pore size and larger capture basket reducing the risk of microembolisation. However, the Nav 6 Emboshield filter has a design that allows the filter and wire to move independently of each other and this may prevent excessive filter movement and loss of protection.[3]

 Procedure



Once the appropriate cutter has been chosen, it is attached to the separately packaged driver handle. There are a few steps involved in preparing the device for usage. There is a side port close to the handle that needs to be flushed. The rest of the steps involve flushing the cutter assembly using the distal flushing tool, which is advanced to the tip of the device until a hard stop is encountered. The cutter window is then opened by moving the orange slider back to the “on” position and turning the driver off at the back of the handle. Rotating the distal nose cone till the black lines do not align opens the catheter flush window and flushing is completed. The distal flushing tool is then returned to its original position and the nose cone realigned. Note that the distal flush tool cannot be moved proximally over an open cutter window.

Once the lesion is crossed and the preferred embolic protection device is in place, the device is introduced over the filter wire. Ensure the wire exits the rapid exchange point rather than through the catheter flush window, which can happen if the nose cone is not rotated completely to align the black lines. Once it is ascertained that the entire length of the lesion can be traversed, the cutter is placed just proximal to the lesion and the device turned on. It is important to keep a constant forward force on the cutter and pack the cut plaque regularly to avoid distal embolization. Multiple passes in different planes can be performed, visualizing the C-shape of the cutter at all times, with magnified views [Figure 4]. The advancement of the cutter inside the packing assembly can be observed under fluoroscopy and the amount of space left in the inner lumen judged [Figure 5]. It is best not to overfill this lumen, as it increases the chance of distal embolization.{Figure 4}{Figure 5}

Once the packing lumen is full, the device will need to be retrieved over the wire and cleaned. Cleaning involves advancing the distal flushing tool over the distal assembly, opening the cutter window and the catheter flush window and flushing hard to extrude plaque from the packing chamber. Hard calcified material may require to be picked out using sharp forceps and once completely clean, the same initial steps are repeated to have the device ready to use again.

Once treatment is completed and angiography confirms <30% residual stenosis, either a drug-coated or plain balloon angioplasty is performed to maximize the lumen gain [Figure 6]. High-pressure inflation is avoided and stenting done only if there is a flow-limiting dissection. The filter is retrieved once the treatment is complete.{Figure 6}

 Troubleshooting and Tips



If the chosen device cannot cross the initial lesion, a small diameter balloon may be used to predilate the lesion. If the LX or LS device does not cross the lesion, then the M or S device with a lower crossing profile can be used. However, the cost-efficacy of opening 2 devices will need to be considered.

Sometimes, if a hard plaque is partially cut then moving the orange slider to the off position will result in resistance and proper packing of the plaque may not be possible. If this occurs, do not force the orange slider forward. Continuing to hold the orange slider in an “on” position and advancing the device further usually allows the plaque to be fully cut at a softer part and then it can be packed away.

In the case of treatment of a previously stented artery, magnified views of the vessel are important to ensure the cutter does not get too close to the stent struts. We do not recommend using the device inside a covered stent. If the cutter gets caught on the stent, it is important not to advance the orange slider forward to the “off” position. Instead, either the cutter can be kept running and the device gently pulled back or the device can be turned off at the back of the handle and then pulled back from the struts before advancing the orange slider forward.

 Literature Review



There is the paucity of data specific to the HawkOne Atherectomy device. However, the SilverHawk and TurboHawk devices have been studied in randomized clinical trials. A recent single-center, prospective randomized trial of 94 patients compared combined treatment of directional atherectomy and drug-coated balloon angioplasty (DR-DCB) versus drug-coated balloon (DCB) angioplasty alone.[4] While there was no statistically significant difference at 12 or 24 months, there was a trend towards better primary patency in the DR-DCB group (80.5% vs. 75.7% at 12 months and 67.1% vs. 55.1% at 24 months). Flow limiting dissections needing bailout stenting was much higher in the DCB group (24.5% vs. 4.4%).

The DEFINITIVE AR trial was a similarly sized and designed randomized trial of 102 patients that showed no difference at 12 months in clinically driven target lesion revascularization rates (7.3% and 8%), duplex ultrasound patency rates (84.6% and 81.3%), and angiographic percent stenosis between DR-DCB versus DCB alone.[1] However again, the requirement for adjunctive treatment with postdilation and/or bail-out stenting was much higher in the DCB group (37% vs. 6.3%). Surprisingly, the rate of stenting in the DCB group was also very low, in this study.

A single-center, nonrandomized study comparing the use of DCB alone versus DR-DCB in isolated popliteal artery disease, showed a higher primary patency rate at 12 months with DR-DCB (82% vs. 65%). Bailout stenting rates were also in favor of DR-DCB (5% vs. 16%).[5] However concerningly, aneurysmal degeneration of the popliteal artery was seen in 7% of cases after DR-DCB. There have been other reports of aneurysmal degeneration of the native artery after directional atherectomy.[6],[7] There is no way of controlling the cutting depth of the HawkOne system except by choosing the correct cutter size for the vessel and subjectively judging the residual stenosis under fluoroscopy.

To better guide the cutting depth of directional atherectomy, the Pantheris catheter system allows for the addition of optical coherence tomography (OCT) guidance. Histological analysis of atherectomy samples obtained this way has shown <1% of adventitia on over 80% of the samples.[8] A retrospective, single-center, single-arm analysis of OCT guided directional atherectomy in the femoropopliteal segment still had one case of target vessel perforation (3%) and 2 cases of aneurysmal degeneration (5%).[9]

 Conclusion



Directional atherectomy in the infra-inguinal arteries allows for significant plaque modification and lumen gain without the use of barotrauma from balloon angioplasty. There is evidence showing a lower incidence of flow-limiting dissections and the need for stenting after such treatment. Theoretically, reduced stenting in the femoropopliteal segment, in particular, should have primary patency benefits in the long-term. This however has not yet been shown conclusively, partly due to the lack of sufficiently powered trials. This theoretical benefit comes at the cost of a higher incidence of distal embolization and target vessel injury with aneurysmal degeneration. Quality trials to directly compare directional atherectomy to other forms of atherectomy in the infra-inguinal arteries are currently not available.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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3Krishnan P, Tarricone A, Gee A, Farhan S, Kamran H, Kini A, et al. Comparison and analysis between the NAV6 embolic protection filter and spiderfx EPD filter in superficial femoral artery lesions. J Interv Cardiol 2021;2021:9047596.
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