Abstract
This analysis compared the angiographic outcomes of patients treated with orbital atherectomy for calcified common femoral artery (CFA) and superficial femoral artery (SFA) disease. The ideal revascularization strategy for CFA disease is unknown. Endarterectomy has been considered the standard of care for CFA disease for over 50 years. Endovascular intervention is becoming more commonly used to revascularize the CFA given the advances in technology and the less invasive nature of the procedure. Patient demographics, lesion characteristics, and procedure data for all CONFIRM patients with at least one CFA lesion location (n=147 patients; n=200 lesions) were compared to patients with at least one SFA lesion location (n=1508 patients; n=2367 lesions). The primary endpoint was angiographic complication, defined as the composite of dissection, perforation, slow flow, closure, spasm, embolism, or thrombosis. The CFA group had more patients with Rutherford class 4 and shorter lesion length. The CFA group had a higher final residual stenosis, shorter total run time, and shorter total inflation time. The primary endpoint was lower in the CFA group compared with the SFA group (17% vs 24%, p=0.02), driven by a lower dissection rate (10% vs 15%, p=0.04). Plaque modification of the CFA with orbital atherectomy was safe and compared favorably with SFA disease. The need for bail-out stenting was low. A randomized trial is needed to determine the ideal treatment strategy for calcified CFA disease.
Introduction
Endovascular intervention is a common treatment strategy for peripheral artery disease (PAD) given that it obviates the need for general anesthesia and a surgical site incision, resulting in lower rates of periprocedural morbidity and mortality and shorter recovery time.1,2 Many vascular surgeons have embraced this change in the treatment paradigm as it is a particularly attractive option for patients who have multiple comorbidities and are poor surgical candidates. However, controversy surrounds the ideal revascularization strategy for common femoral artery (CFA) disease. The argument against endovascular intervention is the potential for dissection requiring stenting and compromising the deep femoral artery, an important collateral vessel. The patency rates are lower compared with surgical revascularization and the data are not as robust.1–7 The presence of moderate to severe CFA calcification increases the complexity of endovascular intervention and may require atherectomy to modify the calcified plaque prior to balloon angioplasty. Endarterectomy has been considered the standard of care for CFA disease for over 50 years, as it is generally considered a technically uncomplicated surgery with durable patency.2–7 The objective of this study was to assess the angiographic outcomes of orbital atherectomy of the CFA compared with the superficial femoral artery (SFA).
Methods
Study design
The CONFIRM I, II, and III registries were large, multi-center, non-randomized, all-comers registries of patients with severely calcified PAD who were treated with orbital atherectomy without exclusion from October 2009 through June 2011. 8 The only inclusion criteria was medically necessary treatment in accordance with the device’s instructions for use (IFU). The severity of calcium was subjectively reported by the principal interventionalist. The CONFIRM registries enrolled 3135 patients with 4766 lesions from over 200 US institutions, representing the largest and most unique resource of its type to date. Informed, written consent was obtained for all participants of the CONFIRM registries. Patient demographics, lesion characteristics, and procedure data for all CONFIRM patients with at least one CFA lesion location (n =147 patients; n =200 lesions) were compared to patients with at least one SFA lesion location (n =1508 patients; n =2367 lesions). Patients with both a CFA and SFA lesion location were excluded. Patients with acute limb ischemia were not included.
Study endpoint
The primary endpoint was angiographic complication, defined as the composite of dissection, perforation, slow flow, closure, spasm, embolism, or thrombus formation.
Device description
Three device iterations of the Orbital Atherectomy System (Cardiovascular Systems, Inc., St Paul, MN, USA) were evaluated over the registry series: CONFIRM I registry evaluated the Diamondback360°; CONFIRM II evaluated the Predator360°; and CONFIRM III evaluated all three devices: Diamondback360°, Predator360°, and Stealth360°. The orbital atherectomy has been previously described. 8
Statistical methods
Patient data were reported as frequency counts and percentages. Quantitative measurements were presented as means and standard deviations. Statistical analysis was performed using available data only, as missing values were excluded from the analysis. Relationships between various patient or lesion characteristics and patient outcomes were analyzed by cross-tab analysis. Rarely observed data categories were combined (e.g. pre-treatment stenosis percentages of less than 70% were collapsed into a single category of stenosis ⩽70%) as necessary to allow sufficient counts in cells for valid chi-squared analysis. Chi-squared (χ2) p-values are reported. P-values <0.05 were considered statistically significant. Statistical analyses were done using SAS version 9.3 (SAS Institute Inc., Cary, NC, USA).
Results
Patient and lesion characteristics
The CFA group had a higher prevalence of Rutherford class 4 compared with the SFA group (24% vs 16%, p=0.02) (Table 1). The CFA group had a shorter lesion length compared with the SFA group (37.8 ± 29.3 mm vs 77.9 ± 76.9 mm, p<0.001) (Table 2).
Baseline patient characteristics.
Data are presented as number (%) or mean ± standard deviation.
CFA, common femoral artery; SFA, superficial femoral artery.
Baseline lesion characteristics.
Data are presented as number (%) or mean ± standard deviation (range).
CFA, common femoral artery; SFA, superficial femoral artery.
Procedural characteristics and adjunctive therapy
The CFA group had a higher final residual stenosis, shorter total run time, shorter total inflation time, more frequent treatment of the deep femoral artery, and a lower number of lesions and vessels treated (Table 3). Adjunctive therapies after orbital atherectomy were similar in both groups (Table 4), with most patients undergoing balloon angioplasty only. Significantly more contrast was administered for CFA-treated patients compared with the SFA-treated patients (164.0 ± 83.6 vs 128.7 ± 76.3, p=0.002) (Supplemental Table).
Procedural characteristics.
Data are presented as number (%) or mean ± standard deviation (range).
CFA, common femoral artery; SFA, superficial femoral artery.
Adjunctive therapy.
Data are presented as number (%).
CFA, common femoral artery; SFA, superficial femoral artery.
Procedural complications
The primary endpoint was lower in the CFA group compared with the SFA group (17% vs 24%, p=0.02), driven by a lower rate of dissection (10% vs 15%, p=0.04) (Table 5) (Figure 1A and 1B). However, the angiographic complication rate was similar (12% vs 12%, p=0.85) if the composite endpoint excluded non-flow-limiting dissection (4% vs 8%, p=0.02). Stenting of the CFA was performed in 40% of procedural dissection compared with 49% in the SFA group (p=0.54). The rate of dissection attributable to the orbital atherectomy crown was higher in the CFA group (40% vs 12%, p<0.001). No patient in the CFA group required conversion to open endarterectomy. The rates of perforation (0% vs 0%, p=0.33), slow flow (2% vs 4%, p=0.22), vessel closure (2% vs 1%, p=0.32), spasm (4% vs 5%, p=0.66), embolism (4% vs 3%, p=0.68), and thrombus formation (0% vs 1%, p=0.14) did not differ between the two groups.
Procedural complications by lesion.
Data are presented as number (%).
CFA, common femoral artery; SFA, superficial femoral artery.
(A) Femoral angiography demonstrates a severe stenosis of the left common femoral artery. (B) Final angiography after orbital atherectomy with a 1.5-mm crown followed by balloon angioplasty with a 6-mm drug-coated balloon demonstrates a good angiographic result.
Discussion
In the first analysis of its kind, no cases of intraprocedural perforation and thrombosis occurred during orbital atherectomy of the CFA. These results compared favorably with orbital atherectomy of the SFA.
This sub-analysis of the CONFIRM registries adds to the limited body of evidence available to date. No patient who underwent orbital atherectomy of the CFA experienced perforation even though the majority of patients were treated with a crown ⩾2 mm (75%). Slow flow and spasm of the CFA were infrequent (2–4%). The impact of intra-arterial nitroglycerin prior to orbital atherectomy to minimize the risk of spasm is unknown, as these data were not collected. The rate of embolism was also low (4%). The impact of distal embolic protection is unknown, as its use was not recorded. The Emboshield NAV6 Embolic Protection System (Abbott Vascular, Santa Clara, CA, USA) is compatible with the ViperWire and can be considered, especially if there is single-vessel run-off.
There is a lack of consensus regarding the optimal endovascular intervention technique (balloon, scoring balloon, stenting, and atherectomy) for CFA disease, especially for heavily calcified vasculature. In addition to the lower patency rates compared with endarterectomy, an argument against endovascular intervention of the CFA is the potential risk of dissection, which may require stenting. Although the CFA group had a lower rate of dissection (10% vs 15%, p=0.04), there was a higher proportion attributed to the orbital atherectomy crown (40% vs 12%, p<0.001). The final residual stenosis was higher in the CFA group (13% ± 12% vs 10% ± 10%, p=0.001), though still below the value of <30% residual stenosis generally defined as a technical success in comparable endovascular studies. 1 Stenting of the CFA is undesirable due to the risk of intimal hyperplasia leading to restenosis and stent fracture due to the repetitive flexion at the inguinal ligament and is a predictor for reintervention and amputation. 1 A strategy of orbital atherectomy followed by balloon angioplasty is an attractive option for the treatment of severely calcified CFA, given the higher risk of dissection, especially in patients who are poor surgical candidates. Drug-coated balloons are also an attractive option due to the lower restenosis rates compared with conventional balloon angioplasty. 9 If angiographic results are suboptimal, self-expanding interwoven nitinol stents (Supera Peripheral Stent, Abbott Vascular, Santa Clara, CA, USA), which are less susceptible to stent fracture, may be a viable treatment option in the CFA as well. Bail-out stenting after orbital atherectomy of the calcified CFA was low (6%), due to the low rates of flow-limiting dissection (4%) and vessel closure (2%).
Unlike the data with endarterectomy, long-term data on patients with CFA disease who underwent endovascular intervention are limited. With few exceptions to date, endovascular intervention of the CFA has predominantly centered on balloon angioplasty and stenting, often in conjunction. At times, these interventions have produced mixed results, which vary with the exact intervention employed. Individual studies and pooled analyses have generally reported procedural success rates of approximately 90–95% for endovascular treatment, with a composite complication rate of 6.9% in one study.1,10,11 These results have been offset by restenosis rates as high as 28.7% for 1-year restenosis and 50% for 5-year restenosis, much higher than those typically observed with endarterectomy. A registry of North American hospitals, which included 1014 patients with either an isolated CFA intervention (n=946) with or without a deep femoral intervention (n=68), reported low rates of dissection (2.9%), distal embolization (0.7%), and perforation (0.6%). 1 Survival at 1-year follow-up was 92.9% and 87.2% after 3 years. Amputation-free survival, freedom from loss of patency or death, and reintervention-free survival were 93.5%, 83%, and 87.5% at 1-year, respectively. The lower dissection rate compared to our study (10%) may be explained by the fact that patients in the registry of North American hospitals included all patients who underwent peripheral intervention, including those without severe calcification. Furthermore, only 19.4% underwent atherectomy.
Data with atherectomy of the CFA are limited. In an analysis of 360 procedures, the 25 patients who underwent atherectomy had a 96% procedural success rate, 0% complication rate, 11.8% 1-year restenosis, and 4.8% 1-year target lesion revascularization. 10 While the small size of this subgroup precluded statistical significance, clinical outcomes with atherectomy compared favorably against PTA with or without stenting. In a study that included 167 patients who underwent endovascular intervention of the CFA, the 32 patients who underwent Jetstream/Pathway atherectomy (Boston Scientific, Marlborough, MA, USA) in addition to balloon angioplasty for claudication, fared better than those who underwent balloon angioplasty alone, with a 20-month patency of 92.3% versus 72%. 12
Multiple studies have reported the outcomes of CFA endarterectomy. It is a readily accessible vessel that does not require bypass grafting and can often be performed with epidural or local anesthesia. An analysis of 111 endarterectomies of the CFA and/or the proximal portion of the SFA or deep femoral artery in 90 patients reported an in-hospital mortality rate of 1.8% and an overall survival rate at the 5, 10, and 15-year follow-up of 60.5%, 32.7%, and 17.6%, respectively. 5 The rates of limb salvage after isolated femoral endarterectomy at the 5, 10, and 15-year follow-up were 93.7%, 93.7%, and 85.2%, respectively. Freedom from any ipsilateral revascularization procedure at the 5, 10, and 15-year follow-up was calculated at 68.0%, 50.6%, and 42.5%, respectively. An analysis of 117 patients who underwent 121 CFA endarterectomies reported no perioperative deaths or major complications. 7 The 7-year primary patency, assisted primary patency, and limb salvage rates were 96%, 100%, and 100%, respectively. The 7-year rates of freedom from further revascularization and survival were 79% and 80%, respectively. A single-center registry of 58 patients who underwent endarterectomy of the CFA reported 1-year and 5-year primary patency rates of 93% and 91%, respectively. 4 Assisted patency was 100% at both time points. Survival was 89% at 1 year and 70% at 5 years. No patient experienced amputation. The National Surgical Quality Improvement Program study reported that CFA endarterectomy was not a benign procedure. 13 The 30-day morbidity/mortality rate was 15% in the 1843 patients who underwent CFA endarterectomy, which compares unfavorably with the data with endovascular therapy in this setting.
Limitations
This is a retrospective analysis of a prospective registry which is subject to selection bias. The analysis of the CFA group was not specified a priori. An angiographic core lab did not adjudicate the angiographic data, allowing for subjective bias. Clinical outcomes, including mortality, repeat revascularization, and amputation-free survival were not reported. Owing to the short duration of follow-up, long-term patency of the CFA after orbital atherectomy is unknown. The CFA, which is a very distinct vascular bed compared with the SFA and is inherently different in terms of diameter, length, exposure to extrinsic forces, outflow, and the presence of bifurcation could be a potential source of differences in treatment outcomes between the two groups. The CFA group had significant differences in baseline patient, lesion, and procedural characteristics. Propensity-matched analysis was not performed. A prospective randomized trial comparing peripheral intervention to endarterectomy is needed to determine the ideal revascularization strategy for CFA disease.
Conclusions
This sub-analysis of the CONFIRM registries reveals that orbital atherectomy of the CFA is feasible and compared favorably with the treatment of SFA stenosis. Orbital atherectomy of the CFA was associated with no cases of vessel perforation and thrombosis and low rates of other angiographic complications. The requirement for bail-out stenting was low. Further studies are needed to compare orbital atherectomy with femoral endarterectomy for the treatment of calcific CFA disease and to evaluate longer-term outcomes.
Footnotes
Declaration of conflicting interests
The authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: ML, JM, and GA have consulting agreements with Cardiovascular Systems, Inc. (St Paul, MN, USA); DH and EM have no conflicts of interest.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: funding for this prospective registry was provided by Cardiovascular Systems, Inc.
