Endoluminal Treatment of Peripheral Chronic Total Occlusions Using the Crosser Recanalization Catheter

ABSTRACT: Purpose. Revascularization of lower extremity chronic total occlusions (CTOs) is technically challenging. The Crosser^® recanalization catheter was designed to facilitate distal vessel intraluminal entry that is both rapid and safe. We present our experience with the Crosser device as primary therapy for peripheral CTOs. Methods. Subjects undergoing evaluation for arterial insufficiency at our institution between 2008–2010 who were noted to have a CTO in the lower extremity by duplex ultrasonography and who subsequently underwent Crosser recanalization were enrolled. Clinical characteristics, ankle-brachial indices, Rutherford-Becker symptom category, and angiographic CTO parameters were collected. Primary technical success was intraluminal delivery of the guidewire into the distal vessel solely by the Crosser device. Secondary technical success was assisted delivery using the Outback LTD^® re-entry device. Safety endpoints were the occurrence of dissections, thromboembolism, and perforations related to the Crosser device. Statistical analysis was performed to find independent predictors for failure to achieve Crosser recanalization. Results. Fifty-six subjects with 73 CTOs were enrolled. The mean Crosser use time was 17.6 ± 12.7 minutes. The overall primary and secondary technical success rates for Crosser recanalization were 76.7% and 87.7%, respectively. Technical success was highest for CTOs located in the aorto-iliac (90.0%) and tibial (95.2%) arterial segments. There were no perforations related to the Crosser device. For successful cases, the mean ABI improved significantly from pre- to post-intervention (0.57 ± 0.13 to 0.89 ± 0.15, p < 0.001). The only predictors for failure were lesion length longer than 100 mm (p = 0.04) and calcification within 10 mm of the exit cap (p = 0.02). Conclusion. The Crosser device is safe and shows excellent efficacy in facilitating guidewire distal lumen entry, especially for aorto-iliac and tibial occlusions. The technical success rate for the femoral and popliteal occlusions is comparable to those reported with other recanalization techniques.

J INVASIVE CARDIOL 2011;23:359–362

Key words: lower extremity disease; peripheral arterial disease

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Chronic total occlusions (CTOs) represent a special subset of lesions that are technically challenging, time consuming, subject to perforations, and often require additional devices to allow access to the distal vessel. The current approach to CTO recanalization involves either the use of a guidewire and support catheter technique or the use of a CTO device. The Crosser^® catheter (C.R. Bard, Inc.) was specifically designed to overcome the limitations of the traditional guidewire method, by facilitating intraluminal entry into the distal vessel that is both rapid and safe. Reports of this device’s safety and efficacy primarily stem from the coronary literature.^1,2 Recently, the effectiveness of this device in superficial femoral artery occlusions has been reported as well.³ In the following report, we present our initial experience with the use of this novel device as first-line therapy throughout the entire lower extremity vascular bed.

Methods

Patient selection. Consecutive subjects who presented to our institution between January 2008 and January 2010 for an evaluation of peripheral arterial disease who were noted to have a CTO at duplex ultrasonography involving any lower extremity segment were enrolled into a registry. All CTOs that underwent Crosser recanalization were included in this study. Subject information was collected regarding demographics, clinical characteristics, ankle-brachial indices (ABI), and Rutherford-Becker symptom category.⁴ The institutional review board approved this data collection.

CTO classification. A CTO was defined as a segment of the lower extremity arteries that showed no forward flow on angiogram and was considered to have been occluded for at least 3 months based on a clinical history of longstanding symptoms and the lack of worsening symptoms in the previous 3 months.

The lower extremity arterial bed was divided into the following five segments: aorta (AO), iliac artery (IL), superficial femoral artery (FEM), popliteal artery (POP), and tibial artery (TIB). A CTO was classified according to the arterial segment where the occlusion started to the segment at which reconstitution was noted. Employing these criteria to the database, five CTO types were noted: AO-IL, FEM-FEM, FEM-POP, POP-TIB, and TIB-TIB. After careful review of the occluded segment in multiple projections, various CTO parameters were collected, including occluded segment length and calcification pattern, entry and exit vessel and cap calcification, and the geometry of the collaterals arising from the entry cap. All lesions within the aorto-iliac and femoro-popliteal beds were characterized according to the TASC II classification.⁵ The characterization of the various parameters required a consensus among four authors who interpreted the images.

CTO parameters and definitions.

1. Occluded Segment Length – Distance measurement of presumed vessel course from entry stump as visualized following contrast opacification to the point of the exit stump reconstitution.
2. Occluded Segment Calcification – Calcification visualized at angiography along the presumed CTO vessel course from the entry stump to the exit stump; considered mild if involvement of 1 wall and < 1/2 of occluded segment length, moderate if 1 wall and > 1/2 of length, moderate-severe if 2 walls and < 1/2 of length, and severe if 2 walls and > 1/2 of length. 
3. Entry Vessel or Exit Vessel Calcification – Calcification visualized at angiography in the 10 mm vessel segments leading up to the entry stump and coursing away from the exit stump prior to any contrast-filling.
4. Entry Cap or Exit Cap Calcification – Calcification visualized by angiography either as present or absent at the entry or exit stump caps prior to any contrast-filling.
5. Collaterals – Any vessel visualized as emerging from the entry stump in either a continuous or bridging pattern.

Interventions. A CTO was considered suitable for Crosser recanalization if the entry stump morphology allowed stable positioning of the tip of the Crosser catheter (all stumps except “flush” occlusions). This technology has been described in detail previously,⁶ but in brief, it involves the transmission of ultrahigh frequency vibrations to the occluded lesion in order to mechanically create a channel that allows a 0.014-inch wire to cross into the distal vessel lumen. Once a channel is created, subsequent atherectomy, balloon angioplasty, and/or stenting can be performed. Figure 1 illustrates the case of a TIB-TIB CTO that was successfully revascularized. If the Crosser device failed to maintain an intraluminal course into the distal vessel, the Outback^® LTD^® re-entry catheter (Cordis Corporation) was used. Anticoagulation during the procedure was achieved using bivalirudin or unfractionated heparin.

Quantitative vascular analysis. All lesion measurements were made using quantitative vascular analysis software (Version 4.4) provided by the GE Cardiovascular Imaging Workstation (GE Healthcare).

Outcome assessment. The efficacy endpoint was primary technical success, defined as successful, intraluminal delivery of the wire into the distal vessel solely by the use of the Crosser device. The secondary technical success rate was defined as successful delivery of the wire into the distal vessel lumen with the use of the Crosser device assisted by the Outback LTD re-entry device.

The safety endpoints were the occurrence of angiographic complications, including dissections, thromboembolism, and perforations. Arterial dissections and thromboembolism were those that were induced by either guidewire manipulation or adjunctive therapy following successful Crosser distal lumen entry. Perforations were those induced directly by the Crosser device.

Statistics. The data was analyzed using the SPSS 10.1 version. Continuous variables were compared using Student’s t-test, while the categorical variables were compared with Fisher’s exact test. The significance level was set for p-values <0.05. Backward multivariate analysis was performed to find independent predictors for failure to achieve primary Crosser recanalization. All demographic and CTO parameters were used in this analysis.

Results

Patient population. This study enrolled 56 subjects (36 men; mean age, 71 ± 10 years) with 73 CTOs who underwent Crosser recanalization. The baseline clinical characteristics of the patients treated are shown in Table 1.

Lesion characteristics. Seventy (95.9%) of CTOs were de novo. The remaining 3 CTOs (4.1%) were restenotic lesions: 1 FEM-FEM occurring along the length of a prior stent and 2 TIB-TIB occurring at sites of previous atherectomy. All CTOs were located in the native vessels. Angiographic parameters of the 73 CTOs are shown in Table 2.

Procedural details. A femoral approach was used in 92% of cases, while 6 AO-IL were performed via radial access. Eighteen CTOs (26.9%) that used the femoral access site were performed via an antegrade route, and the rest of the lesions were approached via retrograde puncture. 6 Fr sheaths were used in 81% of cases, and 7 Fr in 19%. Anticoagulation was achieved with unfractionated heparin in 8% of cases, with bivalirudin in 92%.

The overall mean Crosser use time was 17.6 ± 12.7 minutes. The mean time from the decision to use the device to having the wire in the distal lumen (decision-to-lumen time) was 14.3 ± 9.0 min. The decision-to-failure time (lesions with failed distal lumen entry by the Crosser device) was significantly higher (27.8 ± 14.9 min; p < 0.001).

Endpoints. In terms of efficacy, the overall primary technical success rate for Crosser recanalization was 76.7% (56 lesions), and there were 17 failures. The technical success rates for each of the 5 CTO types are depicted in Table 3. Fifteen (88.2%) of the Crosser failures occurred during interventions of FEM-FEM, FEM-POP, and POP-TIB CTOs. An Outback^® LTD^® Reentry catheter was utilized for 10 failures with successful reentry in 8 more cases. The remaining 7 Crosser failures were aborted. The secondary technical success rate was 87.7% (64 cases). For successful cases, the mean ABI improved significantly from pre- to post-intervention (0.57 ± 0.13 to 0.89 ± 0.15; p < 0.001).

Safety. There were no perforations related to the Crosser device. There were 12 dissections (16.4%) and 6 thromboembolic events (8.2%) recorded, all attributed to the adjunctive therapy performed after successful distal wire reentry. Two thromboembolic events required aspiration thrombectomy for resolution, whereas the remaining 4 cases resolved with the use of pharmacologic therapy. The adjunctive therapy included the following: balloon angioplasty alone for 9 lesions, atherectomy alone for 22, atherectomy and stenting for 6, and balloon angioplasty and stenting for 27.

Predictors. A backward multivariate analysis was performed in order to determine the independent predictors of failure to achieve primary Crosser recanalization. The only predictors for failure were lesion length longer than 100 mm (p = 0.04) and calcification within 10 mm of the exit vessel coursing away from the exit cap (p = 0.02).

Discussion

The present study supports the use of the Crosser catheter as primary therapy in treating lower extremity CTOs as a safe and fast technique. The success rate of central-luminal crossing of total occlusions is excellent for aorto-iliac and tibial occlusions (90% and 95%, respectively). Although the success rate achieved for femoral and popliteal CTOs is similar with those reported using wire techniques and the Frontrunner device,7 this vascular territory remains challenging.

The use of the Crosser catheter seems to ensure a very safe approach to CTOs, as there were no perforations associated with the use of this device in our study. This is in contrast with the 3.3% risk of perforations associated with the use of conventional guidewire techniques⁸ and the 3.8% perforation rate observed with the use of Frontrunner device.⁷ The current study is in line with the safety data reported by use of this device in the coronary arteries^1,2 as well as the data reported from the PATRIOT study,⁹ demonstrating a success rate of 81.2% and no complications with the use of the Crosser device in 85 occlusions following conventional guidewire failure. More recently, a group reported one Crosser device-related perforation in their 27-lesion series.³

The main benefit to using the Crosser catheter likely resides in its ability to differentiate between plaque and normal vessel wall based upon their differing elastic properties. As such, the ability to transfer greater vibrational energy and thus cavitating potential to more dense plaque may contribute to its tendency to stay within the vessel lumen. The excellent primary technical success rate when used in the tibial vessels makes the Crosser a first-line device for use in this vascular territory. This is particularly important due to the lack of reentry devices adequate for these vessels and the critical nature of these lesions. The same high success rate was achieved in the aorto-iliac bed, although the exact role of Crosser for these particular lesions remains to be defined in larger series.

Totally occluded femoral and popliteal arteries remain the most challenging lesions to be recanalized. The primary success rate achieved in lesions involving the superficial femoral artery were in the moderate range of 62–70%. The main predictors of failure in these lesions were occluded segment length more than 100 mm, and the presence of severe calcification within the vessel wall within 10 mm of the exit cap. Approximately two-thirds of the FEM-FEM and FEM-POP lesions in this study were greater than 100 mm in length, which may have in part accounted for the reduced technical success observed. The contribution of exit vessel calcification to failure may be related to the inability of the Crosser to discriminate the inelastic exit cap from the inelastic vessel wall.

Although the data in the literature regarding the time devoted to crossing a CTO are sparse and non-standardized, this study shows that the use of the Crosser catheter allows for a very short time required to cross the totally occluded vessels. The mean time from the decision to use the device to having the wire in the distal lumen (decision-to-lumen time) was 14.0 ± 10.0 min. The decision-to-failure time in unsuccessful cases was 27.8 ± 14.9 min. Because of the lack of standardized data regarding the decision-to-lumen or decision-to-failure times, one cannot compare this technique with other approaches employed when treating total occlusions. Nevertheless, Galassi and colleagues reported that the Crosser catheter when used as a primary, front-line strategy in complex coronary CTOs not only achieved a high rate of clinical success but with less fluoroscopy time when compared to conventional guidewire techniques.²

Limitations. This is a relatively small study, using a novel technology to treat total occlusions. Furthermore, it was at the discretion of the operator to choose the type of lesion to be treated with this device, which might have introduced a selection bias.

Conclusion

The Crosser device is a safe, new endovascular tool. It shows excellent efficacy in facilitating guidewire distal lumen entry for aorto-iliac and tibial occlusions. The primary success rate for the femoral and popliteal occlusions is comparable to those reported with other recanalization techniques.

References

1. Tiroch K, Cannon L, Reisman M, et al. High-frequency vibration for the recanalization of guidewire refractory chronic total coronary occlusions. Catheter Cardiovasc Interv. 2008;72(6):771-780.
2. Galassi AR, Tomasello SD, Costanzo L, et al. Recanalization of complex coronary chronic total occlusions using high-frequency vibrational energy CROSSER catheter as first-line therapy: a single center experience. J Interv Cardiol. 2010;23(2):130-138.
3. Khalid MR, Khalid FR, Farooqui FA, et al. A novel catheter in patients with peripheral chronic total occlusions: a single center experience. Catheter Cardiovasc Interv. 2010;76(5):735-739.
4. Rutherford RB, Baker JD, Ernst C, et al. Recommended standards for reports dealing with lower extremity ischemia: revised version. J Vasc Surg. 1997;26(3):517-538.
5. Adam DJ, Bradbury AW. TASC II document on the management of peripheral arterial disease. Eur J Vasc Endovasc Surg. 2007;33(1):1-2.
6. Gandini R, Volpi T, Pipitone V, Simonetti G. Intraluminal recanalization of long infrainguinal chronic total occlusions using the Crosser system. J Endovasc Ther. 2009;16(1):23-27.
7. Charalambous N, Schafer PJ, Trentmann J, et al. Percutaneous intraluminal recanalization of long, chronic superficial femoral and popliteal occlusions using the Frontrunner XP CTO device: a single-center experience. Cardiovasc Intervent Radiol. 2010;33(1):25-33.
8. Ko YG, Kim JS, Choi DH, et al. Improved technical success and midterm patency with subintimal angioplasty compared to intraluminal angioplasty in long femoropopliteal occlusions. J Endovasc Ther. 2007;14(3):374-381.
9. Joye J. The PATRIOT (Peripheral Approach to Recanalization in Occluded Totals) study results. Am J Cardiol. 2007;100(Suppl 1):S24.

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From ¹Cardiac and Vascular Institute, NYU Medical Center, New York, New York and the ²Department of Cardiovascular Medicine, Saint Vincent’s Catholic Medical Centers, New York, New York.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr. Staniloae reported receiving grants from CSI and honoraria from CSI and Cordis. He reported that he is a consultant to Flowcardia. No other authors reported disclosures.
Manuscript submitted April 19, 2011, provisional acceptance given May 23, 2011, final version accepted July 1, 2011.
Address for correspondence: Cezar S. Staniloae, MD, NYU Langone Medical Center, Cardiac and Vascular Institute, 550 First Avenue, New York, NY 10016. Email: cezar.staniloae@nyumc.org