True lumen re-entry devices facilitate subintimal angioplasty and stenting of total chronic occlusions: Initial report
Article Outline
Objective
The acute technical failure of endovascular treatment of chronic total occlusions (CTOs) is most often due to the inability to re-enter the true lumen after occlusion is crossed in a subintimal plane. This study reports our initial experience with true lumen re-entry devices in the treatment of CTOs.
Methods
Patients with treatment of CTOs were identified from our vascular registry. All patients in whom the Pioneer catheter or the Outback catheter were used were also identified from a prospectively maintained separate database of cases in which true lumen re-entry devices were used. We used procedural data from the prospective database and reviewed the medical records. Lesion character and location, access type, location of true lumen re-entry, stent usage, procedural times, and complications, were tabulated.
Results
From August 2003 to December 2004, endovascular techniques were used to treat 87 CTOs in 58 iliac and 29 superficial femoral arteries. In 24 (26%), the true lumen could not be re-entered by using standard catheter and wire techniques. The true lumen was not initially re-entered in 20 (34%) of 58 of treated iliac CTOs and four (13%) of 29 of treated superficial femoral artery CTOs (73% TASC C and D lesions). Intravascular ultrasound-guided true lumen re-entry using the Pioneer catheter (21 CTOs), or fluoroscopic-guided true lumen re-entry using the Outback catheter (3 CTOs) was successful in achieving true lumen re-entry in all cases at the location desired. Total time of re-entry catheter manipulation required to achieve re-entry was <10 minutes and was routinely accomplished in <3 minutes. All occlusions were stented. No cases were converted to open repair. Bleeding from the recanalization and angioplasty site occurred in four patients (15%). It was controlled with use of covered stents in two cases, and resolved after placement of uncovered stents in the other two. No significant bleeding occurred at the sites of true lumen re-entry needle deployment. All occlusions treated with true lumen re-entry devices remain clinically patent at a mean follow-up of 5.8 months.
Conclusions
Endovascular treatment of chronic total occlusions is often limited by the inability to re-enter the true lumen after subintimal crossing of the occluded segment. This occurs more commonly with treatment of iliac occlusions than in superficial femoral artery occlusions. True lumen re-entry catheters are very effective at gaining wire passage back to the true lumen and facilitating successful endovascular treatment of chronic total occlusions that would otherwise require open bypass.
Endovascular treatment of chronic total occlusions (CTOs) is increasing. The most common method for crossing occlusions uses hydrophilic wires and catheters, often, if not always, in the subintimal plane for a portion of the occlusion. Although recanalization through a CTO is often challenging, the primary limitation to successful treatment of CTOs is reported to be the failure to re-enter the true lumen after subintimal crossing of the occlusion.1, 2, 3 This may be an increasingly important limitation to procedural success as the complexity of lesions treated endovascularly increases.
An additional limitation in some cases is that the true lumen re-entry is not achieved until subintimal passage to a site significantly remote from the level of vessel lumen patency, causing subintimal angioplasty or stenting, or both, to extend beyond the occluded segment. This may put additional branch points, collaterals, and potential “no-stent zones,” such as the common femoral and popliteal arteries adjacent to occluded segments, at risk of the complications of angioplasty and stenting due to the potential inaccuracy of the point of true lumen re-entry.
Devices that have been developed to facilitate true lumen re-entry offer the potential to overcome this limitation to the acute success of treating CTOs. In this report, we describe our initial experience with true lumen re-entry devices in the endovascular treatment of iliac and superficial femoral artery CTOs.
Methods
All patients who had endovascular treatment of iliac and superficial femoral artery CTOs during the study period were identified on an intention-to- treat basis from our vascular registry. All patients in whom the Pioneer catheter (Medtronic, Inc, Minneapolis, Minn) or the Outback catheter (LuMend, Redwood City, Calif acquired by Cordis Corporation, Miami Lakes, Florida) was used in the treatment of their CTO were identified from a prospectively maintained separate database of all cases in which true lumen re-entry devices were used. Institutional Review Board approval of the data collection and analysis in this group of patients was obtained.
A retrospective review was conducted of this prospectively collected data, and the clinical record and follow-up of all cases was also reviewed. Indication for intervention, lesion character as defined by the TransAtlantic InterSocietal Consensus (TASC) classification,4 lesion location, access type, location of true lumen re-entry, stent use, procedural times, anesthesia, and complications, were tabulated. Clinical patency was defined by symptomatic relief of rest pain or improvement in claudication, maintenance of a palpable pulse, and the increase of >0.1 in ankle/brachial index (ABI).
Follow-up intervals were 1 month, 6 months, and annually thereafter. Ultrasound imaging at follow-up was routinely done for femoral interventions at the same intervals, but routine follow-up imaging was not done for iliac interventions.
Technique
Arterial access was typically retrograde femoral for iliac occlusions and contralateral retrograde femoral for femoral occlusions. Less frequent were contralateral retrograde common femoral access for external iliac occlusions and antegrade common femoral access for superficial femoral occlusions. Brachial access was not used for iliac or femoral occlusions. Open access was used when common femoral occlusive disease required open repair or endograft repair was planned of an infrarenal AAA with an associated iliac occlusion. All patients were systemically heparinized before the CTO was manipulated.
CTOs of the iliac and femoral arteries were crossed with combinations of a hydrophilic 0.035-inch Glidewire (Terumo, Somerset, NJ) or a 0.035-inch Acqwire (ev3, Plymouth, Minn) guidewire and a 3F Glidecath hydrophilic catheter (Terumo). Additional support with sheaths or guidewires, or both, was used as needed for access as well as for pushability for crossing occlusions. It is important to note that retrograde iliac recanalization was routinely performed with the direct backup of an ipsilateral femoral sheath or its dilator, or both.
Femoral occlusions were routinely crossed with the backup of a 7F 55-cm sheath placed from the contralateral femoral artery over the aortic bifurcation with the tip into the femoral artery as close to the occlusion as possible. Occasionally, balloon angioplasty of a portion of the occlusion was required to facilitate crossing the remaining occlusion.
Additionally, the back end of the hydrophilic wire was occasionally used to cross short, resistant segments of a CTO. No lasers or mechanical dissector devices were used to cross occlusions.
No standard technique was used to place the wire intentionally subintimal; however, subintimal passage was thought to be present in almost all of the CTO crossings and was obvious in all cases requiring the use of true lumen re-entry devices. Successful true lumen re-entry was defined as re-entry ≤2 cm of the optimal angiographically defined target vessel beyond the occlusion without compromise of significant collaterals or branches. Iliac artery occlusions were routinely stented with balloon-expandable stents in the common iliac artery.
If the wire was not in the true lumen after the CTO was crossed, attempts to gain access to the true lumen with catheter wire manipulations were routinely tried, with additional catheters, wires, guides, and balloons used to gain access to the true lumen. Gentle contrast injections in the dissection plane were used to define any communication to the true lumen. If access to the true lumen failed after 10 minutes of manipulation, a true lumen re-entry device was used.
The Pioneer catheter (Fig 1) is a 7F intravascular ultrasound (IVUS) catheter with a solid-state transducer that uses the In-Vision IVUS system (Volcano Therapeutics, Rancho Cordova, Calif). The catheter has a monorail 0.014-inch delivery lumen. The 0.035-inch wire used to cross the occlusion is exchanged for a 0.014-inch wire to deliver the Pioneer catheter into the dissection plane at the point of desired true lumen re-entry.
Fig 1.
Pioneer intravascular ultrasound true lumen re-entry catheter with needle deployed.
The Pioneer has a hypo-tube through the lumen with a curved retractable nitinol needle distally. The curved needle tip is advanced in a controlled fashion to extend up to a distance of 7 mm and projects away from the IVUS catheter at the 12 o’clock position on the IVUS image. The true lumen is identified by both the two-dimensional and color-flow imaging of the catheter. The catheter is rotated to place the true lumen target at 12 o’clock on the IVUS image and the needle is deployed (Fig 2).
Fig 2.
Pioneer catheter intravascular ultrasound image with catheter in the dissection plane of an iliac above an occlusion traversed subintimally.
An exchange length extra-support 0.014-inch guidewire is then passed from the end of the catheter through the needle and into the true lumen. The needle is retracted, and then the Pioneer catheter is withdrawn, leaving the extra-support wire traversing the occlusion and into the true lumen beyond. The 0.014-inch guidewire was typically then exchanged for a 0.035-inch wire to facilitate iliac or superficial femoral artery (SFA) angioplasty and stenting. Occasionally, the intima traversed at the point of true lumen re-entry must be dilated by using a 0.014-inch balloon (4- or 5-mm diameter) to enable a catheter to pass to exchange for the 0.035-inch wire.
The Outback catheter is a 5F multipurpose type angled guide catheter with an integral hypo-tube ending in a curved nitinol needle that can be advanced or retracted from the end of the catheter to penetrate from the dissection plane to the true lumen (Fig 3). The needle is retracted and the device delivered over the wire to the point of true lumen re-entry. The multipurpose angle of the catheter is manipulated to point the end toward the true lumen by fluoroscopic guidance. The needle is then advanced to deploy it through the intima to the true lumen. A 0.014-inch extra-support wire is then advanced into the true lumen (Fig 4). The Outback catheter is then removed and the wire exchanged, with or without 0.014-inch balloon dilation as noted, for the 0.035-inch wire that is used to perform iliac and femoral angioplasty and stenting. In cases that required stenting to within 2 cm of the inguinal ligament, self-expanding nitinol stents were used in external iliac occlusions after pre-dilating.
Fig 3.
Outback catheter with needle retracted (A) and deployed (B).
Fig 4.
Outback catheter with needle (arrow) and wire deployed into true lumen of femoral artery distal to occlusion.
Minor extravasation of contrast after angioplasty or stenting is treated by temporary balloon occlusion and re-evaluation. Persistent or large extravasations are treated with balloon inflation until preparations are made for the delivery of a Fluency covered stent (CR Bard Inc, Murray Hill, NJ). By not using a sheath, the Fluency stents were able to be placed without increasing the arterial puncture size. The Fluency delivery catheter is passed over the wire after quickly deflating the occluding balloon and removing the balloon and sheath. After removal of the covered stent delivery catheter, the 7F or 8F sheath that was originally used can be replaced and is hemostatic at the puncture site.
All femoral artery occlusions were angioplastied and provisionally stented with self-expanding nitinol stents. Routine completion angiography was done to evaluate for distal embolization, thrombosis, or dissection after all interventions were complete.
All patients were treated with aspirin. All patients with infrainguinal interventions were administered clopidogrel (75 mg/day) for a minimum of 6 weeks.
Results
During a 16-month period from August 2003 to December 2004, 127 iliac and 76 femoral arteries were treated with endovascular techniques, of which 87 (43%) were CTOs. Fifty-eight (46%) of the 127 iliac lesions and 29 (38%) of the 76 femoral lesions were CTOs. All CTOs in the iliac and femoral vessels were successfully treated during the study period on an intention-to-treat basis.
In 24 (28%) of 87 of the CTOs treated, the true lumen could not be re-entered by using standard catheter and wire techniques, and a true lumen re-entry catheter was used. A true-lumen re-entry catheter was used in 20 (34%) of 58 of the iliac artery CTOs. Only 4 (14%) of 29 SFA CTOs required use of a true lumen re-entry catheter.
The Pioneer IVUS-guided true lumen re-entry catheter was used in 21 vessels in 20 patients (18 iliac arteries and 3 SFAs). The Outback fluoroscopic-guided true lumen re-entry catheter was used in three vessels in two patients (2 iliac arteries and 1 SFA). Two patients (one with each catheter type) required true lumen re-entry bilaterally for bilateral iliac artery occlusions.
Lesion characteristics were 7 unilateral common iliac occlusions, 6 total common and external iliac occlusions, 4 bilateral common iliac occlusions, 3 unilateral external iliac occlusions, 3 long femoral occlusions >10 cm, and 1 short 3-cm femoral occlusion. Mean length of the occlusions were 4.1 cm for the common iliac artery occlusions, 8.0 cm for the external iliac occlusions, and 15.3 cm for the contiguous common and external iliac occlusions. Overall, iliac artery occlusion length was 8.1 cm. The SFA occlusions were 3 cm, 12 cm, 15 cm, and 24 cm in length for a mean femoral occlusion length of 13.5 cm.
The Table lists the TASC classification for the 22 patients. Two patients had total iliac artery occlusions treated at the time of placement of a bifurcated aortic stent-graft for infrarenal aortic aneurysms via open femoral access. Two additional patients had open common femoral artery access for treatment of significant common femoral artery disease. All other cases were done percutaneously.
Table I. TransAtlantic InterSocietal Consensus (TASC) classification of the 22 patients who required true lumen re-entry devices
| TASC B | TASC C | TASC D | |
|---|---|---|---|
| Iliac | 5 | 3 | 10 |
| Femoral | 1 | 0 | 3 |
| Total | 6 | 3 | 13 |
The study group included 24 CTOs in 22 patients (18 men and 4 women, mean age 61). Indication for intervention in these 22 patients was rest pain or tissue loss in 12 patients and severe claudication in 10. True lumen re-entry was successful in all cases at the level of vessel reconstitution within 2 cm of the optimal angiographically defined target vessel beyond the occlusion without compromise of significant collaterals or branches. Total time of re-entry catheter manipulation required to achieve re-entry was <10 minutes and was routinely accomplished in <3 minutes. Overall mean fluoroscopy time was 38 minutes, with the first four cases averaging 52 minutes of fluoroscopy and the last four cases only averaging 26 minutes of fluoroscopy. All occlusions were stented. No cases were converted to open repair.
No embolic complications occurred in the patients treated with true lumen re-entry devices. The only complications that occurred were bleeding at the site of recanalization and angioplasty in four patients (18%). All bleeding complications were manifested at the time of the procedure. Neither of the patients with an associated AAA had bleeding complications. Indeed, all four instances of bleeding occurred in cases of iliac artery CTO recanalization not associated with an AAA, making the bleeding complication rate for this subset of patients 25%. Bleeding was controlled with use of covered stents in two cases and was resolved after placement of uncovered stents in the other two. None of these patients had transfusions or prolonged length of stay. It is important to note that no significant bleeding occurred at the sites of true lumen re-entry needle deployment.
All occlusions treated with true lumen re-entry devices demonstrated clinical success at a mean follow-up of 5.8 months (range, 1 to 17 months). All patients undergoing iliac artery reconstructions had palpable femoral pulses and all with SFA reconstructions had palpable popliteal pulses at follow-up. All patients showed an increase of >0.1 in their ABI. ABIs for the 15 patients who completed 6-month follow-up showed a mean pre-procedure ABI of 0.58 and a mean 6-month ABI of 0.97.
Discussion
The ability to treat CTOs was initially limited primarily by the failure to cross the occlusion, then by the failure of balloon angioplasty. With the development of stents to treat failed angioplasty, the primary cause for acute procedural failure in the treatment of CTOs became the inability to cross back into the true lumen after crossing the occluded segment.1, 2, 3 To overcome this technical challenge, two catheters were developed to allow for passage of a needle and guidewire across the intima distal to the occlusion. Two other case series (one with seven CTOs and another with five CTOs) and one single case report on using these true lumen re-entry catheters have been reported.3, 5, 6 To our knowledge, this report is the first to analyze the use of these catheters in a consecutive series of CTO recanalizations.
The first catheter, initially released in August 2002, was the Crosspoint catheter from TransSonics, later acquired by Medtronic, Inc, and renamed the Pioneer catheter (Fig 1). The IVUS integrated to the device allows for real-time imaging at the time of needle deployment. In addition to showing the intima and true lumen, the color flow capability of IVUS imaging adds an additional confirmation of the patency of the vessel at the point of needle deployment.
The presence of calcium can limit IVUS imaging, but its presence is also an important vessel characteristic in that calcium is a limitation to needle penetration of the intima. All of the cases in our series with prominent calcification were successfully treated, and as such, we were not able to define a pattern or amount of calcium that would preclude re-entry with these devices.
The catheter does require 7F sheath access and will not track in a sharply angulated fashion due to the 0.014-inch monorail delivery system and the size and rigidity of the transducer at the end of the catheter. This rigidity at the end is an advantage in providing backup to the needle for penetration of plaque or thickened intima at the time of deployment. The catheter expense and availability of IVUS may be the primary limitations to the widespread use of the Pioneer.
The Outback catheter (Fig 2) had an initial limited release by Lumend in November 2003. Its simple design and lack of need for the IVUS console make it an attractive device. The angled guide and needle hypo-tube are easily tracked in the over-the-wire method using extra-support 0.014-inch wires. The fluoroscopic imaging guidance is limited in the iliac position owing to soft tissue attenuation of the image, particularly in obese patients. The imaging of the orientation of the Outback device in the leg is very good.
The curved guide often resists positioning itself pointing at the true lumen and rides off the convexity of the outside of the intima. Also, the needle deployment is less controlled and, with the limited experience in our hands, seemed to penetrate the intima less effectively; it routinely took several attempts to penetrate. The newest design of the Outback, the Outback LTD, was not used in this study, but has been used subsequently. This limited experience suggests that the fluoroscopic imaging and needle deployment aspects of the Outback device have significantly improved compared with the initial version (LuMend and its Outback LTD catheter was acquired by Cordis Corporation in September, 2005).
Overall, both devices are very effective at their intended use. It is our opinion that either of these devices can significantly improve the acute procedural success of treating CTOs, particularly when treating TASD C and D iliac lesions (Fig 5).
Fig 5.
A, Total iliac occlusion recanalized and required true lumen re-entry at the distal aorta. B, Final angiography shows patent iliac after stenting.
It is also our opinion that the accuracy of achieving true lumen re-entry at the point desired is an advantage that was not fully recognized before this experience with the re-entry devices. This is true for both iliac and femoral artery applications. Retrograde dissection to the distal aorta in common iliac occlusions can put the inferior mesenteric artery at risk of occlusion if the true lumen is entered above its origin. Profunda collaterals to the femoral and popliteal arteries can also be occluded if the dissection extends distal to their reconstitution. Lipsitz et al7 reported that up to 47% of the collaterals distal to and 26% of the collaterals proximal to subintimally treated CTOs of the lower extremity are lost after angioplasty.
Not extending the dissection from the external iliac artery to an uninvolved common femoral artery, or the superficial femoral artery to an uninvolved popliteal artery, avoids the need for angioplasty or stenting, or both, of these vessels that are known to have poorer long-term patency rates. Additionally, limiting the extent of intimal dissection and angioplasty in such cases may preserve surgical options. For example, precise placement of the point of re-entry into a reconstituted above-knee popliteal artery may preserve the option of an above-knee femoropopliteal bypass in the event of long-term failure of angioplasty or stenting, or both, of a femoral occlusion.
The incidence of perforation seen in the treatment of iliac occlusions in this study is high compared with other series.8, 9 Although there was concern that the use of needles and manipulation for true lumen re-entry in these cases might put the patients at risk of bleeding, the sites of significant bleeding were not at the point of needle deployment, but rather in the middle of the chronic occlusions in the common and external iliac arteries.
The need to use true lumen re-entry likely resulted in a selection of patients that have more severe disease. This is substantiated by the high complexity of the lesions treated in this series as defined by their TASC classification. It is strongly recommended that covered stent technology be available to treat perforation when treating complex iliac CTOs.
This series may indicate a rate of re-entry device use that others would consider unnecessarily high; however, the incidence of failure to re-enter the true lumen as a cause of failure in treating CTOs is similar to other studies.1, 2, 3 It is reasonable to assume that the high complexity of the lesion morphology increased utilization rates of these devices. Regardless, the rapid and precise nature of re-entry achieved with these devices may also have resulted in a higher rate of utilization of the devices as we became familiar with their capability.
Conclusion
Our initial experience with true lumen re-entry catheters for treatment of CTOs suggests that the technical success rate for endovascular treatment of these lesions is enhanced by the use of these devices, particularly in the complex iliac occlusions. Precision and ease of treatment are important secondary benefits. We believe these devices are essential tools in our toolbox for endovascular treatment of patients with lower-extremity occlusive disease.
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Competition of interest: Donald L. Jacobs, MD, is a consultant for Cordis Corp. and Medtronic Inc.
PII: S0741-5214(06)00414-9
doi:10.1016/j.jvs.2006.02.051
© 2006 The Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.
