Endovascular first strategy for de novo TransAtlantic Inter-Society Consensus C and D femoro-popliteal disease: Mid-term outcomes from a single tertiary referral center

Abstract

Purpose:

Describe outcomes after endovascular intervention of TransAtlantic Inter-Society Consensus C and D femoro-popliteal disease.

Materials and methods:

Retrospective cohort study. Patient demographics, ankle-brachial indices, and lesion details were analyzed from a prospectively maintained database. In all, 980 limbs treated with percutaneous transluminal angioplasty ± stenting of the femoro-popliteal segment between 2005 and 2012 were reviewed. Seventy-six patients representing 83 limbs with de novo TransAtlantic Inter-Society Consensus C and D lesions measuring ≥15 cm continuously were identified (mean age 71.3 ± 12.1 years, 62% male).

Results:

Twenty-five (30.1%) limbs were treated for severe claudication and 58 (69.9%) for critical limb ischemia. The mean pre-procedural ankle-brachial index was 0.47 ± 0.19. The mean lesion length was 22.9 ± 4.82 cm. Seventy patients representing 77 limbs were available for a mean follow-up length of 19.5 months (range 0–79). The mean post-procedural ankle-brachial index was 0.71 ± 0.28. Primary, assisted-primary, and secondary patency rates were 68.1%, 72.7%, and 83.3% at 6 months, 55.3%, 63.6%, and 58.3% at 12 months, and 38.2%, unavailable, and 10.4% at 24 months, respectively.

Conclusions:

Angioplasty-first strategy for TransAtlantic Inter-Society Consensus C and D lesions of the femoro-popliteal artery can be safely performed. However, patency drastically decreases after 12 months suggesting further improvements are required to achieve longer-term clinical benefit.

Keywords

Endovascular TASC-C TASC-D femoro-popliteal superficial femoral artery stent

Introduction

According to the 2007 TransAtlantic Inter-Society Consensus (TASC-II) guidelines for the management of peripheral artery disease, percutaneous transluminal angioplasty (PTA) is the preferred treatment for TASC-A/B lesions, surgical bypass is recommended for good-risk patients with TASC-C/D lesions, and endovascular therapy is reserved as secondary treatment for TASC-C lesions. Many patients with TASC-C/D lesions have medical comorbidities that place them at high risk for surgical bypass and therefore depend on endovascular techniques for revascularization. Many centres are now using endovascular therapy as the primary treatment for TASC-C/D lesions and reserving surgical therapy for failed endovascular intervention.

There has been a shift toward primary endovascular treatment of extensive lesions and acceptable short- and mid-term outcomes following endovascular intervention of femoro-popliteal artery (FPA) lesions have been published.¹ However, studies reporting longer-term outcomes in TASC-C/D lesions have yielded mixed results.^2–8 Therefore, endovascular therapy as the primary treatment for TASC-C lesions remains controversial and surgical bypass is recommended for surgical candidates with TASC-D lesions. As literature is limited by short-term follow-up, it is difficult to ascertain whether endovascular therapy for TASC-C/D lesions results in sustained clinical benefit. The objective of this study was to describe real-world outcomes following endovascular first strategy (angioplasty ± stenting) for long-segment continuous TASC-C/D lesions involving the FPA in a large volume tertiary referral center.

Materials and methods

Patients

All patients who underwent FPA intervention between 2005 and 2012 were included in a prospectively maintained database. Nine hundred-eighty angiographic reports/images documented between 2005 and 2012 were reviewed. A total of 76 patients underwent endovascular intervention for de novo TASC-C/D continuous lesions of the FPA measuring ≥15 cm and representing 83 interventions were included in this study. The mean age was 71.3 ± 12.1 years and a majority of patients were males (62%). TASC classification was determined through description found within angiography reports. Only patients with de novo stenoses/occlusions of the FPA were included for analysis. Exclusion criteria included: TASC A/B lesions, previous endovascular therapy in the same limb, previous bypass surgery in the same limb, presence of FPA aneurysm at the time of intervention, and TASC C/D lesions that do not consist of continuous occlusions measuring at least 15 cm. Seventy-seven limbs in 70 patients were included for calculating patency (83 limbs used for descriptive statistics) once six patients without follow-up data were removed. Patients were classified into two groups, claudicant vs. critical limb ischemia (CLI), as determined by Rutherford's classification system.⁹ Limbs with pre-procedural Rutherford scores of 2/3 were considered claudicants and limbs with scores of ≥4 were considered to have CLI. Twenty-five (30.1%) limbs were severe claudicants with pre-procedural Rutherford scores of 2/3 and the remaining 58 (69.9%) limbs were identified as having CLI with scores of 4–6. Fourteen (56.0%) limbs with claudication and 33 (56.9%) limbs with CLI received stents during the intervention (Table 1). Indications for intervention included claudication, ischemic rest pain, and tissue loss. Of the 58 limbs treated for CLI, nine (15.5 %) limbs were treated for rest pain and 49 (84.5%) limbs were treated for tissue loss. Post-procedural Rutherford scores, ankle-brachial index (ABI), duplex ultrasound, and toe waveforms (if ABI unreliable or unattainable) were used to document changes from baseline. Interventions were individualized to each patient and determined by the attending physician based on patient presentation, noninvasive diagnostic procedures, and findings after angiography. Demographic information was obtained through the electronic medical record (Table 1). Review Board approval was obtained through our institution.

Table 1.

Patient and lesion characteristics.

Patient characteristics
Total limbs treated, No.	83
Male, %	61.8
Age, mean ± SD, y	71 ± 12
Comorbidities, %
Hypertension	80.6
Diabetes mellitus	55.6
Chronic renal insufficiency	23.6
Coronary artery disease	45.8
Congestive heart failure	13.2
Hyperlipidemia	50.0
Active smoking	22.2
Prior smoking	43.1
Indication, %
Claudication	30.1
Ischemic rest pain	10.8
Tissue loss	59.1
Rutherford 2	11.0
Rutherford 3	17.0
Rutherford 4	11.0
Rutherford 5	18.3
Rutherford 6	42.7
Lesion characteristics
TASC-C, %	50.7
TASC-D, %	49.3
1 runoff vessel, %	44.6
2/3 runoff vessels, %	55.4
PTA, %	43.3
PTA + Stent(s), %	56.7
Mean lesion length, mean ± SD, cm	22.9 ± 4.82

TASC: TransAtlantic Inter-Society Consensus; PTA, percutaneous transluminal angioplasty.

Procedural details

A total of six interventionalists were involved in performing interventions. An antegrade approach was used in 52 limbs and retrograde approach used in 31 limbs. Arterial access was achieved through inserting 5-8F sheaths over a 0.035-inch wire. Standard arteriograms and/or selective arteriography of the FPA and infrapopliteal runoff vessels were subsequently obtained. Interventions were performed following administration of a standard weight-based dose of IV heparin. Stenoses were traversed in true lumen manner and occlusions were crossed using a combination of wires and catheters. Both true lumen or subintimal revascularization techniques were utilized depending on physician's preference in patients with total occlusion. The type and length of balloon device and length of vessel to be treated was determined by the physician. Post-angioplasty arteriography was performed to determine patency of the FPA. At this point, the decision was made to terminate the procedure, re-angioplasty, or deploy self-expanding stents. Stents were placed for the treatment of flow-limiting dissections or the presence of residual stenosis >50%. A variety of stent-types were deployed and include Epic (Boston Scientific Corp.), Lifestent (Bard), Protégé EverFlex (eV3 Inc.), Sentinol (Boston Scientific Corp.), SMART (Cordis Corp.), SUPERA (IDEV Technology), and Zilver (Cook Medical). No atherectomy devices were utilized. Of the 83 limbs, one required an antegrade-retrograde approach to achieve revascularization. An Outback LTD reentry catheter (Cordis) was used in four limbs to facilitate lumen reentry. Following the insertion of the stent(s), repeat balloon angioplasty was performed along the course of the stent. Post-intervention arteriograms were obtained to confirm patency. Hemostasis was achieved using compression or with the use of a closure device.

At some point within the timeframe of the study it became common practice at our institution to prescribe 75 mg of Clopidogrel daily for a minimum of three months and 81 mg of aspirin thereafter. Patients were encouraged to initiate or continue an exercise program if they had the functional capacity to do so.

Patient and procedural characteristics

Nine hundred-eighty angiographic reports/images documented between 2005 and 2012 were reviewed. A total of 76 patients underwent endovascular intervention for de novo TASC-C/D continuous lesions of the FPA measuring ≥15 cm and representing 83 interventions were included in this study. The mean age was 71.3 ± 12.1 years and a majority of patients were males (62%). Twenty-five (30.1%) limbs were severe claudicants with pre-procedural Rutherford scores of 2/3 and the remaining 58 (69.9%) limbs were identified as having CLI with scores of 4–6. Of the 58 limbs treated for CLI, nine (15.5 %) limbs were treated for rest pain and 49 (84.5%) limbs were treated for tissue loss. Fourteen (56.0%) limbs with claudication and 33 (56.9%) limbs with CLI received stents during the intervention (Table 1).

Follow-up

Frequency of clinic visits following intervention was determined by the physician and patient compliance. Patients were typically seen at 1, 3, and 6 months following the procedure and at 6–12-month intervals thereafter. Follow-up consisted of interval history, physical exam, and noninvasive diagnostic studies including arterial duplex ultrasound, pulse volume recordings, toe pressure and waveform measurement, and ABI. Patients who experienced recurrent symptoms with diagnostic testing that demonstrated the presence of re-stenosis or re-occlusion subsequently had angiography if they were candidates for further intervention. Clinical changes following the procedure were determined by Rutherford's classification system.⁹ Follow-up information was obtained through retrospectively reviewing electronic medical records.

Definitions and classifications

According to the TASC-II guidelines, TASC-C lesions were defined as multiple stenoses and/or occlusions of the FPA that collectively measures ≥15 cm in length. TASC-C lesions in this study were continuous lesions that measured ≥15 cm in length. TASC-D lesions were defined as continuous lesions measuring ≥20 cm and include chronic total occlusions of the FPA.

Definitions used in this study follow the standards proposed by Diehm et al.¹⁰ partially summarized below. Interventions were considered technically successful if ≤30% of residual stenosis was identified on angiography after revascularization. Primary patency was defined as uninterrupted patency of the FPA calculated from the initial procedure until re-occlusion in those who required surgical bypass or amputation. Assisted-primary patency was defined as patency following a prophylactic intervention to prevent re-occlusion (i.e. following re-stenosis of treated vessel). Secondary patency was defined as patency of the initially treated vessel following a re-intervention to restore patency after an occlusion of a stent or vessel. Assisted-primary and secondary patency was calculated from the date of the initial intervention until the last day of follow-up or date of re-occlusion noted prior to surgical intervention (i.e. amputation). Re-stenosis was defined as a decrease in ABI >0.15 or evidence of stenosis by duplex ultrasound showing a peak systolic velocity of >300 cm/s. Re-occlusion was determined by absence of arterial flow on duplex ultrasound. Clinical improvement was defined as improvement by at least one clinical category defined by Rutherford et al.⁹ Limbs with CLI experienced clinical improvement if complete healing of skin lesions and resolution of ischemic rest pain was achieved. Patients who underwent surgical bypass or limb amputation were not considered patent for outcome analysis. Periprocedural complications include morbidity and mortality that occurred within 30 days following the procedure.

Statistical analysis

Statistical analysis was performed using SPSS version 20 (IBM SPSS, Chicago, 2011) and SAS version 9.3 (SAS institute Inc. Cary, NC). Kaplan-Meier survival analysis was performed; survival time was calculated in months. The estimated mean and median survival time with its standard error (SE) and 95% confidence interval (CI) was calculated for each category (not reported). Further, a comparison of the survival function between categories was performed via the Log-Rank test. Survival curves and patency rates at each time interval are provided. A p value <0.05 was considered statistically significant.

Results

The mean lesion length was 22.9 ± 4.82 cm. The mean stent length was 20.1 ± 9.8 cm and 23.8 ± 10.8 cm for limbs with claudication and CLI, respectively. The mean pre-procedural ABI of the 62 patients with available data was 0.47 ± 0.19. The remaining 14 patients did not have ABI values documented in the medical record. Thirty-seven (44.6%) of limbs had single-vessel runoff and 46 (55.4%) had 2/3-vessel runoff.

Forty-three (51.8%) limbs required one or more (cumulative total 67) adjunctive endovascular interventions (angioplasty ± stenting). This includes the common iliac artery (n = 2), ipsilateral external iliac artery (n = 2), contralateral external iliac artery (n = 1), ipsilateral common femoral artery (n = 2), popliteal (n = 25), tibioperoneal trunk (n = 8), anterior tibial artery (n = 10), posterior tibial artery (n = 7), and peroneal artery (n = 25). Of the 67 required adjunctive interventions, only four (6.0%) stenoses/occlusions noted in infrapopliteal vessels were unable to be traversed. Three (4.5%) patients required adjunctive endovascular treatment due to distal emboli noted following FPA angioplasty. Eleven of 25 (44.0%) limbs with claudication required adjunctive intervention compared to 32 of 57 (56.1%) limbs with CLI. Of the total number of adjunctive interventions, 0/2 common iliac, 2/2 ipsilateral external iliac, 0/1 contralateral external iliac, 2/2 ipsilateral common femoral, 18/25 popliteal, 7/8 tibioperoneal trunk, 8/10 anterior tibial, 6/7 posterior tibial, and 10/10 peroneal interventions were required in limbs with CLI.

Immediate outcomes

Technical success was achieved in 78 (94.0%) interventions. Periprocedural complications included: in-stent thrombosis in three patients (one with claudication and two with CLI) requiring tissue plasminogen activator and embolectomy; thrombus in the contralateral common femoral artery in one patient requiring thrombolysis and endarterectomy; peroneal emboli in two patients on post-procedural angiography, one who was treated with PTA of the tibioperoneal trunk and heparin while the other patient was observed in the day unit and remained asymptomatic; groin hematoma in two patients, one who subsequently experienced a vasovagal episode during manual compression after failed closure device insertion; pseudoaneurysm of the puncture site in one patient treated by thrombin injection; arterial access failed in one patient requiring a retrograde popliteal approach resulting in successful intervention; a total of two deaths occurred within one month of the procedure (30 day mortality rate of 1.3%) in which one patient died 17 days following intervention due to congestive heart failure and one patient died soon after the intervention for unknown reasons.

Follow-up

The mean follow-up length was 21.67 months (range, 0–79 months) excluding six patients without any follow-up information. Twenty-nine (37.7%) limbs were available for follow-up at 12 months. The mean ABI documented on the first post-procedural clinic visit was 0.71 ± 0.28 (4–6 weeks post-procedure). ABI values were unavailable in four patients and unattainable/unreliable in 11 patients due to the presence of calcification. Of the 42 limbs with pre- and post-intervention ABI values, 28 (67.7%) attained hemodynamic improvement (increase in ABI of ≥0.15), which was sustained in 14 (33.3%) patients without the need for repeated intervention. Of the five procedures that were considered unsuccessful, two limbs (40.0%) had persistent flow-limiting stenoses found on duplex imaging one day after the procedure, one of which required a below-the-knee-amputation (BKA) within 17 days following the procedure and the other patient was lost to follow-up. Re-occlusion was noted one day after the procedure in one patient and did not have re-intervention until 18 months later. One patient with limited follow-up data claimed no clinical benefit was realized.

The overall mean Rutherford score decreased from 4.65 ± 1.44 at baseline to 3.0 ± 2.24 following intervention. The mean score decreased from 2.62 ± 0.50 to 1.56 ± 1.42 for claudicant limbs and from 5.38 ± 0.80 to 3.69 ± 2.21 for limbs with CLI. Of the 36 limbs with CLI and available pre- and post-procedural Rutherford scores, 14 (38.9%) experienced clinical improvement including seven (19.6%) that were asymptomatic with or without the need for minor amputation and 17 (47.2%) that experienced no change or progression in symptoms. Of the 18 limbs with claudication and available pre- and post-procedural Rutherford scores, 14 (77.8%) limbs experienced clinical improvement including five (29.4%) that became asymptomatic and four (23.5%) that experienced no change or worsening of symptoms.

There were 37 limbs from 32 patients with CLI that were treated for limb salvage (pre-procedural Rutherford scores of 5/6) and available for follow-up. Eight (21.6%) limbs experienced complete wound healing (post-procedural Rutherford score of ≤3). Ten (27.0%) limbs required surgical bypass after failed endovascular intervention, two of which subsequently required amputation. A total of 16 (19.3%) limbs required amputation, 10 (12.0%) of which were considered major amputations. Seven patients required amputation of one or more toes (one patient required toe amputations in both feet), two patients required transmetatarsal amputation, and one patient required a partial heel amputation during a debridement procedure for a heel ulcer. The minor amputation rate was 8.4%. Three limbs required BKA and seven required above-the-knee-amputation (AKA). All patients who required amputation experienced successful healing of their surgical site.

Of the 54 limbs classified under the primary-patency group for outcome analysis, 11 (20.4%) required surgical-bypass or major amputation. Reasons for surgical-bypass included: in-stent stenosis and a nonhealing ulcer in one limb, in-stent occlusion in one limb, re-occlusion of the FPA in two limbs, and sustained gangrene in one limb. Reasons for major amputation included: in-stent occlusion with nonhealing ulcers in one limb (BKA), in-stent occlusion (AKA), re-occlusion in two limbs, CLI causing sepsis in one patient (AKA), and sustained gangrene in two patients (BKA and AKA). Primary patency rates at 6, 12, and 24 months were 68.1%, 55.3%, and 38.2%, respectively (Figure 1 and Table 2).

Figure 1.

Survival curve analysis demonstrating primary, assisted-primary, and secondary patency following endovascular intervention.

Table 2.

Freedom from target lesion revascularization patency and limb salvage rates.

	Time (months)
	1	3	6	12	24	36	48	60	72	80
Primary	86.7 ± 4.7	72.2 ± 6.3	68.1 ± 6.6	55.3 ± 7.5	38.2 ± 7.8	21.5 ± 7.7	17.2 ± 7.2	17.2 ± 7.2	17.2 ± 7.2	–
Assisted	100 ± 0.0	90.9 ± 8.7	72.7 ± 13.4	63.6 ± 14.5	–	–	–	–	–	–
Secondary	100 ± 0.0	100 ± 0.0	83.3 ± 10.8	58.3 ± 14.2	10.4 ± 9.7	10.4 ± 9.7	10.4 ± 9.7	0	0	0
TASC-C	87.4 ± 5.3	71.5 ± 7.3	66.0 ± 7.7	59.7 ± 8.2	38.9 ± 9.4	31.1 ± 10.2	23.4 ± 10.2	23.4 ± 10.2	23.4 ± 10.2	–
TASC-D	94.4 ± 3.9	88.5 ± 5.4	76.7 ± 7.2	53.6 ± 8.9	26.3 ± 8.5	10.5 ± 6.7	10.5 ± 6.7	0	–	–
2/3 runoff	94.9 ± 3.5	86.5 ± 5.6	78.0 ± 6.9	64.7 ± 8.3	41.1 ± 9.4	34.3 ± 10.0	27.4 ± 10.1	27.4 ± 10.1	27.4 ± 10.1	–
1 runoff	86.3 ± 5.7	72.4 ± 7.4	63.8 ± 8.0	48.6 ± 8.5	21.7 ± 8.5	5.4 ± 5.2	5.4 ± 5.2	0	0	0
Claudicant	95.8 ± 4.1	95.8 ± 4.1	82.3 ± 8.0	72.6 ± 9.6	39.6 ± 11.3	31.7 ± 11.5	23.8 ± 11.0	–	–	–
CLI	88.3 ± 4.5	71.9 ± 6.4	65.6 ± 6.8	48.8 ± 7.5	27.7 ± 7.8	11.1 ± 6.8	11.1 ± 6.8	5.5 ± 5.2	5.5 ± 5.2	–
PTA	88.3 ± 5.5	79.5 ± 6.9	76.5 ± 7.3	62.6 ± 8.7	35.8 ± 9.9	28.7 ± 10.2	28.7 ± 10.2	0	0	0
PTA/Stent	92.7 ± 4.1	79.4 ± 6.5	66.1 ± 7.7	51.2 ± 8.4	28.8 ± 8.4	11.5 ± 7.1	5.8 ± 5.4	5.8 ± 5.4	5.8 ± 5.4	0
Rutherford 2/3	95.5 ± 4.4	95.5 ± 4.4	80.6 ± 8.7	69.9 ± 10.4	45.3 ± 12.0	36.2 ± 12.6	27.2 ± 12.3	–	–	–
Rutherford 4--6	88.3 ± 4.5	71.9 ± 6.4	65.6 ± 6.8	48.8 ± 7.5	27.7 ± 7.8	11.1 ± 6.8	11.1 ± 6.8	5.6 ± 5.2	5.6 ± 5.2	–

TASC: TransAtlantic Inter-Society Consensus; CLI: critical limb ischemia; PTA: percutaneous transluminal angioplasty; - indicates no further data available and no endpoint (occlusion, surgery) reached. Patency rate in % ± standard error.

Twenty-three limbs underwent re-intervention (PTA ± stenting), 11 for re-stenosis and 12 for re-occlusion. The mean time to revascularization was 5.4 ± 4.1 months. Of the 23 limbs that required re-intervention, three (13.0%) required multiple re-interventions, six (26.1%) required surgical bypass, three (13.0%) required minor amputation, and three (13.0%) required major amputation. Of the 12 limbs that experienced re-occlusion, seven (58.3%) limbs were salvaged by endovascular intervention, three (25.0%) limbs required surgical bypass, and one (8.3%) limb required AKA. Assisted-primary patency was 72.7%, 63.6%, and unavailable and secondary patency was 83.3%, 58.3%, and 10.4% at 6, 12, and 24 months, respectively (Figure 1 and Table 2). No significant differences in patency were observed between primary, assisted-primary, and secondary patency (p = 0.764).

As demonstrated in Table 2, patency rates were calculated based on TASC classification (Figure 2), number of pre-procedural runoff vessels (Figure 3), clinical severity (claudicant vs. CLI; Figure 4), procedural method (PTA vs. PTA + stent(s); Figure 5), and pre-procedural Rutherford classification (Figure 6). Limb salvage rates at 6, 12, and 24 months were 88.2%, 80.0%, and 75.0%, respectively (Figure 7 and Table 2). A significant difference in patency was found in limbs with 2/3 vs. single-vessel runoff (p = 0.031). A trend toward significant differences in patency was found in claudicant vs. CLI limbs (p = 0.108) and pre-procedural Rutherford classification of 2/3 vs. 4–6 (p = 0.088). No difference in patency was observed between TASC classifications (p = 0.564) or procedural methods (p = 0.256).

Figure 2.

Survival curve analysis demonstrating patency in TransAtlantic Inter-Society Classification (TASC) C and D limbs following endovascular intervention.

Figure 3.

Survival curve analysis demonstrating patency following endovascular intervention in limbs with 1 or 2/3 pre-procedural tibioperoneal runoff vessels.

Figure 4.

Survival curve analysis demonstrating patency in limbs treated for claudication or critical limb ischemia following endovascular intervention.

Figure 5.

Survival curve analysis demonstrating patency following endovascular intervention in limbs treated with percutaneous transluminal angioplasty (PTA) alone or with stenting.

Figure 6.

Survival curve analysis demonstrating patency following endovascular intervention according to pre-procedural Rutherford classification.

Figure 7.

Limb salvage rates following primary endovascular intervention.

Five patients died during the follow-up period. One patient died 13 days following the procedure due to a CHF exacerbation, one patient died 36 days following the intervention of unknown cause, one patient died four months following the procedure from pneumonia, one patient died from a myocardial infarction eight months following the procedure, and one patient died for unknown reasons at an unknown date following the procedure.

Discussion

The efficacy of endovascular therapy for TASC-A/B lesions of the FPA has been well documented.^11–14 In contrast, endovascular therapy for TASC-C/D lesions remains controversial. Studies reporting outcomes after intervention of severe FPA lesions are limited in number and follow-up is often short. The TASC-II guidelines recommend traditional surgical bypass for TASC-C/D lesions. Yet, many high-volume centres have adopted endovascular therapy as the initial treatment of choice in response to the acceptable short- and mid-term patency rates published in the literature (Table 3).

Table 3.

Patency rates following endovascular therapy of TASC-C/D femoro-popliteal lesions within the literature.

Study	Limbs	CLI, %	TASC, %	Lesion length, cm	Primary patency, %				Secondary Patency, %
Study	Limbs	CLI, %	TASC, %	Lesion length, cm	6 m	12 m	24 m	36 m	6 m	12 m	24 m	36 m
Baril et al.³	79	71	100, TASC-D	19 ± 11.5		52	27.5			93	89
Bosiers et al.⁴	100	29	N/A	24 (range 16--45)	85	65
Davaine et al.⁵	3923	5470	63, TASC-C37, TASC-D	18 ± 633 ± 8		8244				8564
Dosluoglu et al.²	49, TASC-C44, TASC-D	7361	53, TASC-C47, TASC-D	10 ± 427 ± 5.5		8354	8028			9872	9854
Kim et al.⁶	63	38	21, TASC-C79, TASC-D	22.7 ± 10.5		52
Laganà et al.⁷	52	N/A	100, TASC-D	N/A	92	77	69		100	100	92
Setacci et al.⁸	145	100	56, TASC-D	17 ± 1.4, TASC-C22 ± 1.8, TASC-D		70	53	34		77	61	43

TASC: TransAtlantic Inter-Society Consensus; NA: not available.

The results in this study represent real-world outcomes in long FPA interventions and therefore some important conclusions can be drawn from the findings. The results suggest that endovascular therapy for TASC-C/D femoro-popliteal lesions can be performed safely and results in acceptable patency at 12 months following the primary intervention. However, patency rates obtained in this study are lower than a majority of those published in the literature. This may be due to differences in patient cohort and lesion anatomy (i.e. all lesions in this study were continuous).

We found that patency is acceptable over the short term but deteriorates rapidly within the second year despite a limb's TASC classification, number of pre-procedural runoff vessels, or clinical presentation at the time of the primary intervention. This finding suggests the continued need to improve techniques in order for endovascular intervention to create long-term benefit. We also note that, although not reaching significance, limbs classified as TASC-D do not do as well as TASC-C limbs at and beyond 12 months following intervention. As patency in TASC-D limbs beyond 24 months appears quite poor, we believe surgical bypass remains the best method to achieve long-term benefit.

We show that limbs with 2/3 pre-procedural runoff vessels achieved significantly higher patency. The clinical implication is that patients with single vessel run-off should be monitored regularly so that re-intervention can take place before complete occlusion or thrombosis of the artery. We also observed a trend toward superior patency in claudicant limbs compared to CLI, implying that not surprisingly, clinical presentation may help to predict patency following intervention. The finding that efficacy of endovascular therapy decreases as the severity of disease increases has been replicated in the literature^6,15–17 and is further supported by this study.

In this series, we found that interventions in patients with TASC C/D femoro-popliteal lesions frequently require concomitant adjunctive procedures (51.8%) on either inflow or outflow lesions. Intervention of the primary femoro-popliteal lesion alone is often insufficient.

The best endovascular approach (PTA vs. PTA ± stenting vs. direct stenting) to produce long-term patency remains unclear. Trials have shown stenting results in better outcomes compared to angioplasty in the treatment of short SFA lesions. However, the majority of trials were for claudicants with TASC A/B lesions (see Table 4). The outcomes of these studies may not be transposed to the CLI population with far advanced TASC lesions and suboptimal run-off vessels. Still, there is no consensus on whether stenting provides a patency advantage over PTA alone in TASC-C/D lesions.

Table 4.

Lesion characteristics and outcomes from studies comparing stenting vs. PTA of femoro-popliteal lesions.

Study	Patients (N)	Lesion length	Claudicant	Re-stenosis Rates	Re-intervention Rates	Patency
VIENNA¹⁸	104	13.2 ± 7.1 cm vs. 12.7 ± 5.5 cm	88% vs. 87%	37% vs. 63% (1 year)	N/A	N/A
Schillinger et al.¹⁹	104	11.2 ± 7.7 cm vs. 9.3 ± 6.5 cm	42% vs. 46%	45.7% vs. 69.2% (2 year)	37.0% vs. 53.8% (2 year)	78.3% vs. 65.4% (2 year)
FAST²⁰	244	4.5 ± 2.8 cm vs. 4.5 ± 2.8 cm	96.6% vs. 95.6%	31.7% vs. 38.6% (1 year)	14.9% vs. 18.3% (1 year)	N/A
RESILIENT²¹	206	7.1 ± 4.4 cm vs. 6.4 ± 4.1 cm	100% vs. 98.6%	N/A	N/A	81.3% vs. 36.7% (1 year)
Nguyen et al.²²	824	N/A	71% vs. 59%	N/A	N/A	41% vs. 36% (5 year)

PTA: percutaneous transluminal angioplasty; N/A, not available.

Note: Table presents values in stent group vs. PTA group.

We report no differences in patency between PTA and PTA + stenting in continuous TASC-C or D FPA lesions, albeit stents were used predominantly when PTA failed. As stenting adds a significant procedural cost, increases the complexity of the initial procedure, and also repeat procedures, primary usage of stents in TASC-C/D lesions needs to be considered carefully. The lesion lengths treated in the current study are greater than all trials included in Table 4. Although we cannot conclude PTA alone is superior to stenting, our results suggest PTA alone may offer similar benefit in continuous FPA lesions measuring at least 15 cm.

Limitations

There are limitations inherent to the retrospective and nonrandomized nature of this study. As this study represents real-world outcomes, there was no control for behaviors following intervention. As well, there may have been clinical and/or anatomic differences in patients treated with PTA alone compared to PTA with stenting. Such differences could potentially influence patency outcomes. The conclusions of this study are limited by the fact that multiple techniques and devices were used (and thus represent real-world experience). The data are limited by varied data completeness and limited follow-up. The high attrition rate by 12 months (37.7%) limits the studies ability to make conclusion on the long-term benefit of treatment. Within-patient dependence exists as several patients included in the study had more than one limb treated. The sample size included in this study is likely too small (as a result of only including continuous lesions >15 cm in length) to delineate optimal outcomes between PTA vs. PTA + stenting. Lastly, Clopidogrel was established as a standard post-procedural medication within the timeframe of this study; therefore, patients may not have been prescribed Clopidogrel or initiated treatment during the follow-up period.

Conclusion

The present study provides outcomes following a real-world experience using endovascular therapy to treat clinically severe and continuous TASC-C/D lesions of the femoro-popliteal segment. Our findings support that endovascular treatment is safe and viable in long-segment lesions that produce acceptable short-term outcomes. However, the clinical benefit obtained by patients following the procedure deteriorates rapidly beyond 12 months and repeat interventions are frequently needed to maintain vessel patency. We therefore believe that bypass must be considered for long-term benefit in surgical candidates with TASC-C/D lesions. Our results also suggest that PTA alone achieves comparable patency and clinical outcomes to limbs treated with stents.

Footnotes

Conflict of interest

None declared.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

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