Abstract
Objectives
The objective of this study was to evaluate clinical outcomes and patency rates using the Viabahn endoprosthesis in complex (TASC-II C and D) femoropopliteal lesions.
Background
Traditional treatment of symptomatic TASC-II C and D femoropopliteal lesions has mainly centered on open surgical options in patients deemed appropriate candidates. Endovascular treatment of these lesions with balloon angioplasty has been historically hampered by aggressive restenosis and relatively early clinical failure. The Viabahn endoprosthesis was developed with the intent of reducing restenosis while improving overall flexibility in the femoropopliteal segment.
Methods
Between March 2009 and July 2011 a total of 51 limbs in 41 patients underwent implantation of one or more Viabahn endovascular stent grafts for the treatment of symptomatic TASC-II C or D lesions. Patients were followed clinically at regular intervals and also underwent routine surveillance duplex ultrasound at 1, 3, 6, and 12 months post-procedure. The average follow-up from the index procedure was 14.6 months (range 13–35.2 months).
Results
A total of 22 TASC-II C and 29 TASC-II D lesions were treated (51 limbs in 41 patients). The mean lesion length was 22.4 cm. The overall 1-year primary patency rate was 74.8% (95% CI: 61.2%–88.4%), assisted primary patency rate was 87.4% (95% CI: 70.9%–95.9%), and the secondary patency rate was 94.9% (95% CI: 88.0%–100.0%).
Conclusions
The Viabahn endoprosthesis is a safe and effective option for the treatment of TASC-II C and D femoropopliteal lesions. Patency rates are favorable despite the complexity of these lesions, although multiple endovascular re-interventions may be necessary to achieve an acceptable long-term result.
Highlights
- •
The objective of this study was to evaluate clinical outcomes and patency rates using the Viabahn endoprosthesis in complex (TASC-II C and D) femoropopliteal lesions.
- •
The 1-year primary patency rate was 74.8%, assisted primary patency rate was 87.4%, and secondary patency rate was 94.9%.
- •
The Viabahn endoprosthesis is a safe and effective option for the treatment of complex femoropopliteal lesions.
- •
Patency rates are favorable despite the complexity of these lesions, although multiple endovascular re-interventions may be necessary to achieve an acceptable long-term result.
1
Introduction
Peripheral arterial disease represents an important public health concern with an estimated 8.5 million people in the United States affected, and an almost 20% prevalence in Americans 75 years and older . Traditional treatment has largely centered on either conservative or surgical options depending on the severity of symptoms; however, the emergence of endovascular therapies has reshaped the current landscape of treatment modalities. In an effort to guide clinicians, the TransAtlantic Inter-Society Consensus Group II (TASC-II) has classified lesions by morphology and recommended treatment modality; Type A and B lesions are preferably treated with endovascular therapy, while more complex Type C and D lesions are preferably treated with surgery in appropriate surgical candidates . Unfortunately, patients with complex peripheral arterial disease often have significant co-morbid conditions that make the risk of surgical revascularization prohibitive . In addition, advances in endovascular techniques and technologies have overcome many of the technical limitations of treating more complex lesion sets, making contemporary endovascular therapy a viable option in challenging cases. The overall technical success rate of percutaneous transluminal angioplasty (PTA) in femoropopliteal segments exceeds 95% , with a greater than 85% success rate for recanalization of total occlusions .
Patients with TASC-II C and D lesion morphology typically have suboptimal results with balloon angioplasty alone, often due to heavy calcification and long lesion lengths . In addition, stand-alone PTA in the femoropopliteal segment carries a high rate of restenosis . Self-expanding nitinol stents have represented an important advance in the treatment of lengthy and recalcitrant lesions; however, restenosis continues to represent an important factor in long-term outcomes . Additionally, stent fractures are not uncommon given the unique shear stresses encountered in the femoropopliteal segment . The Viabahn expandable polytetrafluoroethylene (ePTFE) stent graft (Gore Medical; Flagstaff, AZ) was developed with the intent of reducing restenosis rates while increasing overall flexibility. The graft consists of an ePTFE liner attached to an external nitinol stent scaffold. In addition, the inside lining is coated with a heparin bioactive surface. The Viabahn stent graft is currently FDA approved for the treatment of lesions in the iliac and superficial femoral arteries (SFAs). The objective of this study was to evaluate clinical outcomes and patency rates using the Viabahn endoprosthesis in complex (TASC-II C and D) femoropopliteal lesions.
2
Materials and methods
2.1
Patient enrollment
We retrospectively evaluated all consecutive patients receiving the Viabahn ePTFE graft at our institution from March 2009 to July 2011. Patients were excluded if Viabahn stent implantation was performed for treatment of aortoiliac disease, popliteal aneurysm exclusion, or sealing of an iatrogenic vessel perforation. In patients receiving Viabahn ePTFE grafts for femoropopliteal lesions, only TASC-II C and D lesions were considered. TASC-II C and D lesions were defined per the TASC-II consensus document, with TASC-II C lesions defined as multiple stenoses or occlusions totaling > 15 cm with or without heavy calcification, or recurrent stenoses or occlusions that need treatment after two endovascular interventions, and TASC-II D lesions defined as chronic total occlusions of the common femoral artery or SFA (> 20 cm involving the popliteal artery) or chronic total occlusions of the popliteal artery and proximal trifurcation vessels.
Patient demographics, comorbidities, pre-procedural ankle brachial indices (ABIs) and Rutherford Classification were collected along with a complete clinical history and physical examination. Indication for the procedure was classified as either lifestyle limiting claudication or critical limb ischemia.
2.2
Procedural details
Angiography was performed using a combination of local and moderate conscious sedation anesthesia. All interventions were performed through 6 or 7 French sheaths using either the contralateral femoral artery for a retrograde approach, the ipsilateral femoral artery for an antegrade approach, or via the brachial arterial approach. Systemic anticoagulation was achieved using unfractionated heparin dosed to maintain an activated clotting time (ACT) greater than 250 s. In addition, all patients received 325 mg of aspirin and, when possible, 600 mg of clopidogrel prior to the procedure.
Standard pre-dilatation balloon angioplasty was performed at nominal pressures for a minimum of two minutes in all patients prior to stent graft implantation. In all cases, adequate balloon expansion was ensured prior to proceeding with stent graft deployment. Balloon diameter was selected angiographically based on the diameter of the non-diseased artery segments proximal and distal to the lesion. Viabahn stent graft implantation was performed using 1:1 sizing based on angiographic findings. If overlapping grafts were required, a minimum overlap of 5 mm was ensured. All stent grafts were post-dilated using an appropriately sized post-dilatation balloon to ensure maximal stent expansion and apposition. Care was taken to ensure that stent grafts were positioned such that the proximal and distal ends were located in angiographically non-diseased portions of the vessel.
2.3
Follow-up
Patients were seen in follow-up at regular intervals of 1, 3, and 6 months, and at other times if the clinical condition warranted. Surveillance duplex ultrasound examinations were performed post-procedure and at 1, 3, 6, and 12 months, or if the clinical history or examination suggested a need for non-invasive imaging. Aspirin was continued indefinitely after the procedure, and clopidogrel was continued for a minimum of 6 months post-procedure, and preferably longer if tolerated. Patients were referred for repeat angiography if there was a significant decline in ABI measurement in the treated limb accompanied by symptoms, abnormal findings suggestive of significant restenosis within 5 mm of the Viabahn stent graft on duplex evaluation (peak systolic velocity ratio (PSVR) ≥ 2.4) in the presence or absence of symptoms, or occlusion noted in the presence of symptoms on duplex evaluation. Primary patency was assessed by a combination of clinical history and routine surveillance ultrasound. Assisted primary patency was defined as the need for re-intervention of the target lesion due to restenosis. Secondary patency was defined as the need for re-intervention of the target lesion due to occlusion. Patients in whom attempts at recanalization of stent graft occlusions were unsuccessful were classified as not having secondary patency.
2.4
Statistical analysis
Data collected were analyzed using the SAS 9.1.3. Software analysis package (SAS Institute; Cary, NC). Kaplan–Meier curves were then constructed to determine the freedom from loss of primary patency, primary assisted patency, and secondary patency at 1 year. A paired student’s t-test was used to compare pre- and post-procedure ABI distributions. The clinical research protocol and data collection methods were approved by the Institutional Review Board at our facility.
2
Materials and methods
2.1
Patient enrollment
We retrospectively evaluated all consecutive patients receiving the Viabahn ePTFE graft at our institution from March 2009 to July 2011. Patients were excluded if Viabahn stent implantation was performed for treatment of aortoiliac disease, popliteal aneurysm exclusion, or sealing of an iatrogenic vessel perforation. In patients receiving Viabahn ePTFE grafts for femoropopliteal lesions, only TASC-II C and D lesions were considered. TASC-II C and D lesions were defined per the TASC-II consensus document, with TASC-II C lesions defined as multiple stenoses or occlusions totaling > 15 cm with or without heavy calcification, or recurrent stenoses or occlusions that need treatment after two endovascular interventions, and TASC-II D lesions defined as chronic total occlusions of the common femoral artery or SFA (> 20 cm involving the popliteal artery) or chronic total occlusions of the popliteal artery and proximal trifurcation vessels.
Patient demographics, comorbidities, pre-procedural ankle brachial indices (ABIs) and Rutherford Classification were collected along with a complete clinical history and physical examination. Indication for the procedure was classified as either lifestyle limiting claudication or critical limb ischemia.
2.2
Procedural details
Angiography was performed using a combination of local and moderate conscious sedation anesthesia. All interventions were performed through 6 or 7 French sheaths using either the contralateral femoral artery for a retrograde approach, the ipsilateral femoral artery for an antegrade approach, or via the brachial arterial approach. Systemic anticoagulation was achieved using unfractionated heparin dosed to maintain an activated clotting time (ACT) greater than 250 s. In addition, all patients received 325 mg of aspirin and, when possible, 600 mg of clopidogrel prior to the procedure.
Standard pre-dilatation balloon angioplasty was performed at nominal pressures for a minimum of two minutes in all patients prior to stent graft implantation. In all cases, adequate balloon expansion was ensured prior to proceeding with stent graft deployment. Balloon diameter was selected angiographically based on the diameter of the non-diseased artery segments proximal and distal to the lesion. Viabahn stent graft implantation was performed using 1:1 sizing based on angiographic findings. If overlapping grafts were required, a minimum overlap of 5 mm was ensured. All stent grafts were post-dilated using an appropriately sized post-dilatation balloon to ensure maximal stent expansion and apposition. Care was taken to ensure that stent grafts were positioned such that the proximal and distal ends were located in angiographically non-diseased portions of the vessel.
2.3
Follow-up
Patients were seen in follow-up at regular intervals of 1, 3, and 6 months, and at other times if the clinical condition warranted. Surveillance duplex ultrasound examinations were performed post-procedure and at 1, 3, 6, and 12 months, or if the clinical history or examination suggested a need for non-invasive imaging. Aspirin was continued indefinitely after the procedure, and clopidogrel was continued for a minimum of 6 months post-procedure, and preferably longer if tolerated. Patients were referred for repeat angiography if there was a significant decline in ABI measurement in the treated limb accompanied by symptoms, abnormal findings suggestive of significant restenosis within 5 mm of the Viabahn stent graft on duplex evaluation (peak systolic velocity ratio (PSVR) ≥ 2.4) in the presence or absence of symptoms, or occlusion noted in the presence of symptoms on duplex evaluation. Primary patency was assessed by a combination of clinical history and routine surveillance ultrasound. Assisted primary patency was defined as the need for re-intervention of the target lesion due to restenosis. Secondary patency was defined as the need for re-intervention of the target lesion due to occlusion. Patients in whom attempts at recanalization of stent graft occlusions were unsuccessful were classified as not having secondary patency.
2.4
Statistical analysis
Data collected were analyzed using the SAS 9.1.3. Software analysis package (SAS Institute; Cary, NC). Kaplan–Meier curves were then constructed to determine the freedom from loss of primary patency, primary assisted patency, and secondary patency at 1 year. A paired student’s t-test was used to compare pre- and post-procedure ABI distributions. The clinical research protocol and data collection methods were approved by the Institutional Review Board at our facility.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
