Superficial femoral artery: current treatment options

The Efficacy of Cone-Beam CT-Based Perfusion Mapping in Evaluation of Tissue Perfusion in Peripheral Arterial Disease

This study investigated the use of cone-beam computed tomography (CBCT)-based perfusion mapping during percutaneous transluminal angioplasty (PTA) to predict clinical outcome in the peripheral arterial disease (PAD). From January 2016 to March 2020, 43 patients (28 male, 15 female; mean age, 69) with 51 limbs, who underwent PTA with CBCT-based foot perfusion mapping for PAD were included. Parenchymal blood volume (PBV) of foot was measured. Clinical response was investigated based on medical records. Predictive value for clinical success was evaluated using multiple logistic regression with C-statistics. Two reviewers visually assessed the improvement on angiography and CBCT-based foot perfusion mapping; inter-observer agreement of clinical success between the two were measured. Technical and clinical success rate of PTA was 90.8% and 68.6%, respectively. In multiple logistic regression, the maximum value of PBV (PBV_max) on perfusion mapping after PTA was significant (p = 0.03) for evaluating clinical success with the highest C-statistic (0.84). Using a cutoff of 235.7 mL/L for PBV_max after PTA, area under curve for prediction of clinical success was 0.664, and sensitivity and specificity were 71.4% and 68.8%, respectively. Consistency in prediction of clinical success between the two reviewers was almost perfect for CBCT-based foot perfusion mapping.

Bypass surgery for chronic lower limb ischaemia

BACKGROUND

Bypass surgery is one of the mainstay treatments for patients with critical lower limb ischaemia (CLI). This is the second update of the review first published in 2000.

OBJECTIVES

To assess the effects of bypass surgery in patients with chronic lower limb ischaemia.

SEARCH METHODS

For this update, the Cochrane Vascular Group searched its trials register (last searched October 2016) and the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (last searched Issue 9, 2016).

SELECTION CRITERIA

We selected randomised controlled trials of bypass surgery versus control or any other treatment. The primary outcome parameters were defined as early postoperative non-thrombotic complications, procedural mortality, clinical improvement, amputation, primary patency, and mortality within follow-up.

DATA COLLECTION AND ANALYSIS

For the update, two review authors extracted data and assessed trial quality. We analysed data using odds ratio (OR) and 95% confidence intervals (CIs). We applied fixed-effect or random-effects models.

MAIN RESULTS

We selected 11 trials reporting a total of 1486 participants. Six trials compared bypass surgery with percutaneous transluminal angioplasty (PTA), and one each with remote endarterectomy, thromboendarterectomy, thrombolysis, exercise, and spinal cord stimulation. The quality of the evidence for the most important outcomes of bypass surgery versus PTA was high except for clinical improvement and primary patency. We judged the quality of evidence for clinical improvement to be low, due to heterogeneity between the studies and the fact that this was a subjective outcome assessment and, therefore, at risk of detection bias. We judged the quality of evidence for primary patency to be moderate due heterogeneity between the studies. For the remaining comparisons, the evidence was limited. For several outcomes, the CIs were wide.Comparing bypass surgery with PTA revealed a possible increase in early postinterventional non-thrombotic complications (OR 1.29, 95% CI 0.96 to 1.73; six studies; 1015 participants) with bypass surgery, but bypass surgery was associated with higher technical success rates (OR 2.26, 95% CI 1.49 to 3.44; five studies; 913 participants). Analyses by different clinical severity of disease (intermittent claudication (IC) or CLI) revealed that peri-interventional complications occurred more frequently in participants with CLI undergoing bypass surgery than PTA (OR 1.57, 95% CI 1.09 to 2.24). No differences in periprocedural mortality were identified (OR 1.67, 95% CI 0.66 to 4.19; five studies; 913 participants). The primary patency rate at one year was higher after bypass surgery than after PTA (OR 1.94, 95% CI 1.20 to 3.14; four studies; 300 participants), but this difference was not shown at four years (OR 1.15, 95% CI 0.74 to 1.78; two studies; 363 participants). No differences in clinical improvement (OR 0.65, 95% CI 0.03 to 14.52; two studies; 154 participants), amputation rates (OR 1.24, 95% CI 0.82 to 1.87; five studies; 752 participants), reintervention rates (OR 0.76, 95% CI 0.42 to 1.37; three studies; 256 participants), or mortality within the follow-up period (OR 0.94, 95% CI 0.71 to 1.25; five studies; 961 participants) between surgical and endovascular treatment were identified. No differences in subjective outcome parameters, indicated by quality of life and physical and psychosocial well-being, were reported. The hospital stay for the index procedure was reported to be longer in participants undergoing bypass surgery than in those treated with PTA.In the single study (116 participants) comparing bypass surgery with remote endarterectomy of the superficial femoral artery, the frequency of early postinterventional non-thrombotic complications was similar in the treatment groups (OR 1.11, 95% CI 0.53 to 2.34). No mortality within 30 days of the index treatment or during stay in hospital in either group was recorded. No differences were identified in patency (OR 1.66, 95% CI 0.79 to 3.46), amputation (OR 1.70, 95% CI 0.27 to 10.58), and mortality rates within the follow-up period (OR 1.66, 95% CI 0.61 to 4.48). Information regarding clinical improvement was unavailable.No differences in major complications (OR 0.66, 95% CI 0.34 to 1.31) or mortality (OR 2.09, 95% CI 0.67 to 6.44) within 30 days of treatment between surgery and thrombolysis (one study, 237 participants) for chronic lower limb ischaemia were identified. The amputation rate was lower after bypass surgery (OR 0.10, 95% CI 0.01 to 0.80). No differences in late mortality were found (OR 1.56, 95% CI 0.71 to 3.44). No data regarding patency rates and clinical improvement were reported.Technical success resulting in blood flow restoration was higher after bypass surgery than thromboendarterectomy for aorto-iliac occlusive disease (one study, 43 participants) (OR 0.01, 95% CI 0 to 0.17). The periprocedural mortality (OR 0.33, 95% CI 0.01 to 8.65), follow-up mortality (OR 3.29, 95% CI 0.13 to 85.44), and amputation rates (OR 0.47, 95% CI 0.08 to 2.91) did not differ between treatments. Clinical improvement and patency rates were not reported.Comparing surgery and exercise (one study, 75 participants) did not identify differences in early postinterventional complications (OR 7.45, 95% CI 0.40 to 137.76) and mortality (OR 1.55, 95% CI 0.06 to 39.31). The remaining primary outcomes were not reported. There was no difference in maximal walking time between exercise and surgery (1.66 min, 95% CI -1.23 to 4.55).Regarding comparisons of bypass surgery with spinal cord stimulation for CLI, there was no difference in amputation rates after 12 months of follow-up (OR 4.00, 95% CI 0.25 to 63.95; one study, 12 participants). The remaining primary outcome parameters were not reported.

AUTHORS' CONCLUSIONS

There is limited high quality evidence for the effectiveness of bypass surgery compared with other treatments; no studies compared bypass to optimal medical treatment. Our analysis has shown that PTA is associated with decreased peri-interventional complications in participants treated for CLI and shorter hospital stay compared with bypass surgery. Surgical treatment seems to confer improved patency rates up to one year. Endovascular treatment may be advisable in patients with significant comorbidity, rendering them high risk surgical candidates. No solid conclusions can be drawn regarding comparisons of bypass surgery with other treatments because of the paucity of available evidence. Further large trials evaluating the impact of anatomical location and extent of disease and clinical severity are required.

The laser driven short-term heating balloon catheter: Relation between the chronic neointimal hyperplasia formation and thermal damage to arterial smooth muscle cells

We proposed a novel laser-driven short-term heating angioplasty to realize restenosis-suppressive angioplasty for peripheral artery disease. In this study, we investigated the chronic intimal hyperplasia formation after the short-term heating dilatation in vivo, as well as the thermal damage calculation on arterial smooth muscle cells (SMCs). The prototype short-term heating balloon catheter with 5.0, 5.5, 6.0 mm φ in balloon diameter and 25 mm in balloon length were employed. The short-term heating dilatation was performed in porcine iliac arteries with dilatation conditions of 75°C (N=4) and 65°C (N=5) as peak balloon temperature, 18 ± 4s as heating duration, 3.5 atm as balloon dilatation pressure. Four weeks after the balloon dilatation, the balloon-dilated artery segments were extracted and were stained with HE and picrosirius red for histological observation. In the case of 75°C as the peak balloon temperature, neointimal hyperplasia formation was significantly reduced. In this case, the SMCs density in the artery media measured from the HE-stained specimen was 20% lower than that in the reference artery. According to the thermal damage calculation, it was estimated that the SMCs lethality in artery media after the short-term heating angioplasty was 20% in the case of 75°C as the peak balloon temperature. We demonstrated that the short-term heating dilatation reduced the number of SMCs in artery media. We think this SMCs reduction might contribute to the suppression of chronic neointimal hyperplasia.

Fracture of self-expanding nitinol stents stressed in vitro under simulated intravascular conditions

OBJECTIVE

The use of intravascular stents in the superficial femoral artery (SFA) continues to be controversial due to the potential for compression and fracture in the tortuous physical environment of the adductor canal. The purpose of this study was to (1) characterize the types and ranges of stent distortion theoretically produced by extremity movement and (2) use these ranges as parameters for in vitro long-term fatigue testing of commercially available self-expanding nitinol stents.

METHODS

Nitinol self-expanding stents were placed in the SFAs of cadavers and lateral view radiographs were obtained with the limb in various degrees of hip and knee flexion. The measured degrees of axial shortening and bending of the stent were estimated by planimetry and used for in vitro fatigue testing, which was undertaken using specially designed equipment. Six different commercially available nitinol self-expanding stents-Protégé EverFlex (EV3, Minneapolis, Minn), S.M.A.R.T. Control (Cordis/Johnson & Johnson, Miami Lakes, Fla), Luminexx (C.R. Bard, Murray Hill, NJ), LifeStent FlexStar (Edwards Lifesciences, Irvine, Calif), and Xceed and Absolute (Abbott Vascular, Santa Clara, Calif)-were mounted in elastic silicone tubing, bathed in phosphate buffered saline at 37 degrees +/- 2 degrees C, and examined for fracture after 10 million cycles of chronic deformation.

RESULTS

For unstented arteries, the distal SFA/proximal popliteal artery exhibited the greatest axial compression (23%) vs the middle SFA (9%) or popliteal artery (14%) at 90 degrees /90 degrees knee/hip flexion. For stented arteries, the popliteal artery exhibited the most axial compression (11%) vs the middle SFA (3%) or distal SFA/proximal popliteal artery (6%) at 90 degrees /90 degrees knee/hip flexion. Axial compression of the stented popliteal artery at 70 degrees /20 degrees knee/hip flexion was 6% with a deflection angle of 33 degrees . These parameters were used for chronic in vitro fatigue testing, which produced a range of responses in commercially available stents. Chronic 5% axial compression resulted in high rates of fracture of Luminexx (80%) and LifeStent FlexStar (50%), with lower fracture rates for Absolute (3%), Protégé EverFlex (0%), and S.M.A.R.T. Control stents (0%). Chronic 48 degrees bending deformation resulted in high rates of fracture in Protégé EverFlex (100%), S.M.A.R.T. Control (100%), and Luminexx stents (100%), with lower rates in Absolute (3%) and LifeStent FlexStar (0%).

CONCLUSION

Nitinol self-expanding stents undergo both axial and bending deformation when implanted into the superficial femoral and popliteal arteries. Commercially available stents exhibit a variable ability to withstand chronic deformation in vitro, and their response is highly dependent on the type of deformation applied.

Role of Stents, Drug-Eluting Stents, and Stent-Grafts in Treatment of Infrainguinal Arterial Disease

Infrainguinal peripheral arterial disease is increasingly treatable by endovascular techniques. Bare-metal, drug-eluting, and covered stents (stent-grafts) are increasingly important adjuncts to percutaneous transluminal angioplasty in the treatment of occlusive and aneurysmal disease. Preliminary data suggest bioabsorbable stents may also have a significant clinical impact as well. In this article, we describe the available evidence supporting use of stents in the femoropopliteal and tibial arteries, as well as some of their limitations and complications.