CryoPlasty therapy of the superficial femoral and popliteal arteries: A reappraisal after 44 months' experience

Laser Atherectomy for the Treatment of Peripheral Arterial Disease

BACKGROUND

The aim of the study was to investigate the clinical results of laser atherectomy in the treatment of peripheral arterial disease.

METHODS

Retrospective analysis of consecutive patients underwent laser atherectomy at a single institution during a 7-year period by vascular surgeons and interventional cardiologists in a tertiary university-affiliated hospital. Clinical data were retrieved from patient charts and hospital electronic medical records along with the associated arteriograms.

RESULTS

A total of 461 lesions in 343 limbs were treated in 300 patients with a mean age of 70 years. The indication was critical limb ischemia (CLI) with rest pain or tissue loss in 227 (66%) of interventions and claudication in 116 (34%). All procedures included an associated balloon angioplasty, while stenting was performed in 33%. Technical success was achieved in 99% with only 2 (<1%) cases with an acute procedure-related complication requiring surgical intervention. At a mean follow-up of 28 months (range, 1-87 months; median 24 months), 156 patients (45%) became asymptomatic or achieved significant clinical improvement (resolution of tissue loss or rest pain), 60 (17%) remained with CLI, 30 (9%) had a major proximal amputation, and 18 (5%) had a minor amputation. Freedom from major amputation was 90% at 5 years by life-table analysis. Univariate statistical analysis demonstrated the risk of a major amputation to be associated with diabetes, hemodialysis, and tissue loss (P < 0.05 to P < 0.005), while multivariate logistic regression analysis indicated diabetes to be overwhelmingly important (RR: 4.84; 95% confidence interval [CI]: 1.1-21.3; P < 0.05). In a similar manner, multivariate analysis indicated dialysis (RR: 2.46; 95% CI: 1.01-5.98; P < 0.05) and CLI (RR: 2.27; 95% CI: 1.42-3.65; P < 0.01) were associated with higher likelihood for lack of clinical improvement. There was no difference in major amputation rates between surgeons and interventional cardiologists (RR: 1.5; 95% CI: 0.7-2.1; P < 0.1) although it was 3 times more likely for the patients treated by surgeons to suffer from CLI (odds ratio: 3.2; 95% CI: 1.9-5.4; P < 0.0001).

CONCLUSIONS

Laser atherectomy is a safe and useful adjunct in limb salvage. Diabetics have much higher probability of requiring a proximal amputation, while those on dialysis and with CLI are least likely to gain clinical benefit.

Cryoplasty for Canine Iliac Artery Stenosis and its Impact on Expression of TIMP-2 and MMP-2

Objective:

This study was performed to observe the effects of cryoplasty on canine iliac artery stenosis and the expression of tissue inhibition of matrix metalloproteinase 2 (TIMP-2) and matrix metalloproteinase 2 (MMP-2).

Methods:

We produced a reliable canine model to mimic the atherosclerotic stenosis in the iliac artery by suturing the artery followed by vessel ligation to create an injury to intimal and medial walls. Sixteen mongrel dogs with iliac artery stenosis were randomized to conventional balloon angioplasty (n = 8) or cryoplasty (n = 8).

Results:

Four weeks posttreatment, the cryoplasty group with less collagen fibers and smooth muscle demonstrated significantly larger luminal diameter of iliac artery compared to the balloon angioplasty group ( P < .001). Expression of TIMP-2 significantly increased and expression of MMP-2 significantly reduced in iliac artery of the cryoplasty group compared to conventional balloon angioplasty.

Conclusion:

Our study suggests cryoplasty might increase the expression of TIMP-2 and decrease the expression of MMP-2, thereby inhibiting vascular hyperplasia and collagen fibers synthesis of the stenotic vessels.

12-month primary patency rates of contemporary endovascular device therapy for femoro-popliteal occlusive disease in 6,024 patients: beyond balloon angioplasty

BACKGROUND

Endovascular approach to superficial femoral artery (SFA) disease, the most common cause of symptomatic peripheral arterial disease, remains fraught with high failure rates. Newer devices including second-generation nitinol stents, drug-coated stents, drug-coated balloons, covered stents, cryo-therapy, LASER, and directional atherectomy have shown promising results. Clinical equipoise still persists regarding the optimal selection of devices, largely attributable to the different inclusion criteria, study population, length of lesions treated, definition of "patency" and "restenosis," and follow-up methods in the pivotal trials.

METHODS

A prospective protocol was developed. We performed a literature search using PubMed from January 2006 to November 2013. Published articles including endovascular interventions in SFA or popliteal arteries with reported 12-month "primary patency" or "binary restenosis" rates as endpoints were included.

RESULTS

We identified 6,024 patients in 61 trials reporting 12-month primary patency rates in patients with femoropoliteal disease. Primary patency rates were (weighted average) 77.2% for nitinol stents, 68.8% for covered stents, 84% for drug eluting stents, 78.2% for drug eluting/coated balloon, 60.7% for cryoballoon, 51.1% for LASER atherectomy, 63.5% for directional atherectomy and 70.2% with a combination of endovascular devices.

CONCLUSION

The most frequently used endovascular devices yielded various 12-month primary patency rates ranging from 51% to 85%. The increased variation in inclusion criteria, length, and complexity of lesions between studies does not allow direct comparison between them. Larger randomized trials in specific patient populations comparing those modalities is needed before we can make safe recommendation of the superiority of one device over the other.

Endovascular techniques in limb salvage: cutting, cryo, brachy, and drug-eluting balloons

The complex pathophysiology response to injury of the lower-extremity arteries has prompted the development of several unique balloon technologies to overcome initial technical failures and short-term intimal hyperplasia. Cryoplasty alters the cellular and mechanical properties of the vessel wall during angioplasty. Cutting balloons incise the wall, preventing elastic recoil and allowing expansion of the lumen at a lower pressure, thus limiting barotrauma. Drug-eluting balloons actively transfer inhibitory compounds to the wall during the initial therapy, while brachytherapy balloons allow for localized delivery of radiation to inhibit the proliferative response seen after angioplasty. These platforms provide unique means to enhance immediate and short-term results and also reduce stent usage in the lower extremity.

Cryoplasty for peripheral arterial disease

BACKGROUND

Percutaneous balloon angioplasty is an endovascular technique for restoring blood flow through an artery that has become narrowed or blocked by atherosclerosis. Narrowing of the artery following angioplasty (restenosis) is the major cause of long-term failure. Cryoplasty offers a different approach to improving long-term angioplasty results. It combines the dilation force of balloon angioplasty with cooling of the vessel wall. This systematic review evaluated cryoplasty in peripheral arterial disease and provides focus for further research in the field. This is an update of a review first published in 2007.

OBJECTIVES

To assess the efficacy of, and complications associated with, cryoplasty for maintaining patency in the iliac, femoropopliteal and crural arteries in the short and medium term.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched October 2012) and CENTRAL (2012, Issue 10). Trial databases were searched for ongoing or unpublished studies. We also searched the reference lists of relevant articles.

SELECTION CRITERIA

All randomised controlled trials in which participants with peripheral arterial disease (PAD) of the lower limbs, or lower limb bypass graft stenoses, were randomised to cryoplasty with or without another procedure versus a procedure without cryoplasty were considered. This included trials where all participants received angioplasty and the randomisation was for cryoplasty versus no cryoplasty and trials where cryoplasty was used as an adjunct to conventional treatment (for example stenting) against a control.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed, assessed and selected trials, extracted data and assessed risk of bias.

MAIN RESULTS

Seven trials (six primary cryoplasty and one adjunctive cryoplasty trial) with a combined total of 478 patients were included in this review. The trials reported patency and restenosis either by participant, lesion or vessel location. Follow-up ranged from 30 days to three years.Target lesion patency measured at various time points in two primary cryoplasty trials showed no statistically significant difference between the treatment groups. The adjunctive cryoplasty study showed that cryoplasty was associated with improved patency only at six months (OR 5.37, 95% CI 1.09 to 26.49, n = 90).Restenosis measured per patient (two primary cryoplasty trials) showed no statistically significant difference between the treatments. Restenosis measured by lesion (two primary cryoplasty trials) showed a statistically significant difference only within 24 hours of the procedure (OR 0.08, 95% CI 0.04 to 0.18, n = 192) favouring cryoplasty.Need for re-intervention was not significantly different in primary cryoplasty trial participants (per participant: OR 0.27, 95% CI 0.05 to 1.52, n = 241, I(2) = 89%; per lesion: OR 0.59, 95% CI 0.06 to 5.69, n = 307, I(2) = 94%). The adjunctive cryoplasty trial did not report on need for intervention.Immediate success of procedure (within 24 hours) was not significantly different in primary cryoplasty trial participants (per participant: OR 1.63, 95% CI 0.14 to 19.55, n = 340, I(2) = 95%; per lesion: OR 1.81, 95% CI 0.19 to 17.36, n = 397, I(2) = 90%). The adjunctive cryoplasty trial reported 100% success.Limb loss, deaths from all causes and the risk of complications immediately after treatment showed no statistically significant differences between the treatments.

AUTHORS' CONCLUSIONS

The benefit of cryoplasty over conventional angioplasty cannot be established as the number of randomised controlled trials is small and their quality is not sufficiently high. The technical success and primary patency rates seen in these trials are inconsistent and do not necessarily suggest a future role for cryoplasty in the treatment of PAD, but they cannot be reliably interpreted. Currently there are insufficient data to support the routine use of cryoplasty over conventional balloon angioplasty in the treatment of PAD.

Cryoplasty offers no advantage over standard balloon angioplasty for the treatment of in-stent stenosis

In-stent restenosis is the primary failure mode of endovascular treatment of occlusive disease in the femeropopliteal segment. Cryoplasty has been proposed to reduce intimal hyperplasia through induction of apoptosis. We sought to evaluate the efficacy of cryoplasty for treatment of in-stent restenosis compared to conventional balloon angioplasty (CBA). After IRB approval, a retrospective record review was performed of reinterventions for in-stent restenosis by a single vascular surgery group at a university hospital. Reinterventions involving cryoplasty and CBA were evaluated at 1, 3, 6 and 12 months after intervention with duplex imaging to identify significant recurrent stenosis utilizing established velocity criteria. Data collected included basic demographic information and comorbidities as well as time to restenosis. Statistical analysis was performed using Kaplan–Meier survival curves with the log rank test, Wilcoxon rank test, and Cox proportional hazards models. From December 2004 to November 2007, 76 reinterventions were performed using CBA (n = 39) or cryoplasty (n = 37) for in-stent restenosis without placement of additional stents. Periprocedural technical success (>30% residual stenosis) was 100% for both groups, with no complications. The two cohorts were statistically similar in mean age, gender, comorbidities, tobacco use and use of statins, aspirin and Plavix. However, the mean lesion length was significantly longer in the cryoplasty cohort (CBA: 140.9 mm, Cyro: 191.7 mm; P = 0.032). The mean time to recurrent stenosis or need for additional secondary intervention was significantly shorter for the cyroplasty cohort than for the CBA, 4.09 and 10.79 months, respectively ( P = .0001). Recurrent stenosis-free survival was significantly lower in the cyroplasty cohort at 3 months (CBA: 96.9%, Cyro: 88.9%) and 6 months (CBA: 84.0%, Cyro: 43.8%; P = .0089). Cyroplasty as a modality for treatment of in-stent stenosis in the femoropopliteal segment offers no benefit over CBA.

Excimer laser with adjunctive balloon angioplasty and heparin-coated self-expanding stent grafts for the treatment of femoropopliteal artery in-stent restenosis: twelve-month results from the SALVAGE study

OBJECTIVES

The aim of the study is to evaluate the safety and effectiveness of treating femoropopliteal in-stent restenosis (ISR) with debulking with excimer laser followed by implantation of a VIABAHN endoprosthesis.

BACKGROUND

The optimal treatment strategy for femoropopliteal ISR is unclear.

METHODS

The SALVAGE study is a multicenter prospective registry involving nine US centers. Patients with femoropopliteal ISR with moderate to severe intermittent claudication or critical limb ischemia (Rutherford categories 2-5) and an ankle-brachial index (ABI) =0.8 were treated with excimer laser and the VIABAHN endoprosthesis. The primary efficacy endpoint is primary patency at 12 months as measured by duplex ultrasonography. The primary safety endpoint is the major adverse event (MAE) rate at 30 days.

RESULTS

Twenty-seven patients were enrolled. The mean lesion length was 20.7 ± 10.3 cm. The majority of lesions were TASC (TASC I) C and D (81.4%). All lesions were pretreated with excimer laser and percutaneous transluminal angioplasty (PTA) prior to VIABAHN implantation. Technical success was achieved in 100% of cases. There were no MAE at 30 days. Primary patency at 12 months was 48%. The ankle brachial index increased from 0.58 ± 0.24 at baseline to 0.90 ± 0.17 at 12 months. There was improvement in all quality-of-life parameters. The 12-month TLR rate was 17.4%.

CONCLUSIONS

The strategy of excimer laser atherectomy and PTA followed by implantation of a self-expanding stent graft for the treatment of femoropopliteal ISR is safe and associated with high procedural success. Primary patency rate at 12-months was suboptimal; however, the TLR rate was low.

Lower extremity limb salvage with cryoplasty: a single-center cohort study

Endovascular techniques have been playing an increasing role in managing lower extremity chronic critical limb ischemia (CLI) in patients considered poor or non-candidates for surgical revascularization secondary to co-morbidities such as coronary artery disease, uncontrolled hypertension, diabetes mellitus or inadequate conduit. This study reviews our recent clinical experience in the treatment of peripheral artery disease solely using cryoplasty. A retrospective cohort study was performed. The cohort consisted of 88 patients who underwent lower extremity revascularization utilizing cryoplasty between December 2003 and August 2007. Indications for intervention included poor wound healing after forefoot amputation or persistent ulceration of the foot, disabling claudication and rest pain. Kaplan–Meier analysis was performed to assess salvage rates. One hundred twenty-six lesions were treated in 88 patients. Technical success rate was 97%. Limb salvage rates were 75 and 63% for patients with critical limbs ischemia after one and three years, respectively. A history of smoking was associated with a threefold increased risk of limb loss. In conclusion, endovascular management of lower extremity lesions with cryoplasty is an emerging and viable paradigm in the treatment of CLI in an attempt to preserve limbs and avoid major amputations.

PolarCath cryoplasty enhances smooth muscle cell apoptosis in a rabbit iliac artery model: an experimental in vivo controlled study

PURPOSE

To in vivo investigate the histological response after single and double cryoplasty therapy in a rabbit iliac artery model.

MATERIALS AND METHODS

In total, 40 New Zealand White rabbits underwent percutaneous transluminal angioplasty of the iliac artery using either PolarCath balloon or a conventional angioplasty balloon of equal diameter. Arterial injury, inflammatory response and smooth muscle cells (SMC) apoptosis with the TUNEL (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling) immunohistochemical assay were analyzed. Rabbits were divided between single or double balloon inflation and histological results were compared between cryoplasty and control angioplasty both at 30 min and 72 h.

RESULTS

Arterial injury and wall inflammation scores were low and similar between cryoplasty and control groups after single and double balloon inflation. Compared to conventional balloon angioplasty, Polarcath cryoplasty demonstrated superior SMC apoptosis after single inflation at 30 min [12.0±1.2 cells/(0.025 mm)2 vs 7.0±1.5 cells/(0.025 mm)(2), p=0.002], single inflation at 72 h [9.0±1.0 cells/(0.025 mm)(2) vs 5.4±1.4 cells/(0.025 mm)(2), p=0.001], double inflation at 30 min [11.6±1.5 cells/(0.025 mm)(2) vs 6.8±1.4 cells/(0.025 mm)(2), p=0.001] and double inflation at 72h [9.2±0.8 cells/(0.025 mm)(2) vs 5.0±0.7 cells/(0.025 mm)(2), p=0.001]. There were no significant differences in apoptosis between single and double cryoplasty application at 30 min and 72 h.

CONCLUSION

Cryoplasty demonstrated superior rates of SMC apoptosis at 30 min and 72 h and was associated to relatively low arterial injury and inflammation scores. An immediate second PolarCath inflation did not achieve superior apoptosis.

Outcomes following treatment of femoropopliteal in-stent restenosis: a single center experience

OBJECTIVES

The aim of this study is to describe a single-center experience with endovascular treatment of femoropopliteal in-stent restenosis (ISR).

BACKGROUND

Femoropopliteal artery stenting is associated with a significant risk of ISR. Data are limited on the optimal treatment strategy and associated outcomes.

METHODS

A single institution retrospective chart review study was performed for patients who underwent endovascular treatment of femoropopliteal ISR from January 2006 to October 2008. Clinical and procedural characteristics, angiographic findings, and 12-month primary and secondary patency rates were analyzed. Univariate analysis was performed to identify predictors of 12-month primary patency.

RESULTS

Twenty-two limbs were treated in 20 patients during the study period. Procedural success was achieved in 21 limbs (95.5%). Laser, balloon angioplasty, and excisional atherectomy were the primary therapy in 52.4%, 33.3%, and 14.3% of the cases, respectively. Adjunctive balloon angioplasty was performed after laser and excisional atherectomy in all cases. The mean length of ISR was 13.2 ± 11.3 cm with a significant proportion of cases (40.9%) having Type IV pattern of ISR. At 12 months, primary and combined primary-assisted and secondary patency rates were 47.6 and 61.9%, respectively. Of the 11 limbs that did not have secondary patency, 6 had mild or no symptoms, and, therefore, repeat intervention was not performed. There was one transmetatarsal amputation during the 12-month follow-up period. In this study, there was no significant predictor of 12-month primary patency.

CONCLUSIONS

Treatment of ISR remains challenging with significant risk of recurrent restenosis. Further research is required to improve long-term patency.

Cryoplasty versus conventional balloon angioplasty of the femoropopliteal artery in diabetic patients: long-term results from a prospective randomized single-center controlled trial

The purpose of this study was to investigate the immediate and long-term results of cryoplasty versus conventional balloon angioplasty in the femoropopliteal artery of diabetic patients. Fifty diabetic patients (41 men, mean age 68 years) were randomized to cryoplasty (group CRYO; 24 patients with 31 lesions) or conventional balloon angioplasty (group COBA; 26 patients with 34 lesions) of the femoropopliteal artery. Technical success was defined as <30% residual stenosis without any adjunctive stenting. Primary end points included technical success, primary patency, binary in-lesion restenosis (>50%), and freedom from target lesion recanalization. Cox proportional hazards regression analysis was performed to adjust for confounding factors of heterogeneity. In total, 61.3% (19 of 31) in group CRYO and 52.9% (18 of 34) in group COBA were de novo lesions. More than 70% of the lesions were Transatlantic Inter-Society Consensus (TASC) B and C in both groups, and 41.4% of the patients in group CRYO and 38.7% in group COBA suffered from critical limb ischemia. Immediate technical success rate was 58.0% in group CRYO versus 64.0% in group COBA (p = 0.29). According to 3-year Kaplan-Meier estimates, there were no significant differences with regard to patient survival (86.8% in group CRYO vs. 87.0% in group COBA, p = 0.54) and limb salvage (95.8 vs. 92.1% in groups CRYO and COBA, respectively, p = 0.60). There was a nonsignificant trend of increased binary restenosis in group CRYO (hazard ratio [HR] 1.3; 95% CI 0.6-2.6, p = 0.45). Primary patency was significantly lower in group CRYO compared with group COBA (HR 2.2; 95% CI 1.1-4.3, p = 0.02). Significantly more repeat intervention events because of recurrent symptoms were required in group CRYO (HR 2.5; 95% CI 1.2-5.3, p = 0.01). Cryoplasty was associated with lower primary patency and more clinically driven repeat procedures after long-term follow-up compared with conventional balloon angioplasty.

Four-year randomized prospective comparison of percutaneous ePTFE/nitinol self-expanding stent graft versus prosthetic femoral-popliteal bypass in the treatment of superficial femoral artery occlusive disease

BACKGROUND

This is a randomized prospective study comparing the treatment of superficial femoral artery occlusive disease percutaneously with an expanded polytetrafluoroethylene (ePTFE)/nitinol self-expanding stent graft (stent graft) versus surgical femoral to above-knee popliteal artery bypass with synthetic graft material.

METHODS

One hundred limbs in 86 patients with superficial femoral artery occlusive disease were evaluated from March 2004 to May 2005. Patient symptoms included both claudication and limb threatening ischemia with or without tissue loss. Trans-Atlantic InterSociety Consensus (TASC II) A (n = 18), B (n = 56), C (n = 11), and D (n = 15) lesions were included. Patients were randomized prospectively into one of two treatment groups; a percutaneous treatment group (group A; n = 50) with angioplasty and placement of one or more stent grafts, or a surgical treatment group (group B; n = 50) with a femoral to above-knee popliteal artery bypass using synthetic conduit (Dacron or ePTFE). Patients were followed for 48 months. Follow-up evaluation included clinical assessment, physical examination, ankle-brachial indices, and color flow duplex sonography at 3, 6, 9, 12, 18, 24, 36, and 48 months.

RESULTS

Mean total lesion length of the treated arterial segment in the stent graft group was 25.6 cm (SD = 15 cm). The stent graft group demonstrated a primary patency of 72%, 63%, 63%, and 59% with a secondary patency of 83%, 74%, 74%, and 74% at 12, 24, 36, and 48 months, respectively. The surgical femoral-popliteal group demonstrated a primary patency of 76%, 63%, 63%, and 58% with a secondary patency of 86%, 76%, 76%, and 71% at 12, 24, 36, and 48 months, respectively. No statistical difference was found between the two groups with respect to primary (P = .807) or secondary (P = .891) patency.

CONCLUSION

Management of superficial femoral artery occlusive disease with percutaneous stent grafts exhibits similar primary patency at 4-year (48 month) follow up when compared with conventional femoral-popliteal artery bypass grafting with synthetic conduit. This treatment method may offer an alternative to treatment of the superficial femoral artery segment for revascularization when prosthetic bypass is being considered or when autologous conduit is unavailable.

The current state of endovascular therapy in the evaluation and management of renovascular disease

Hypertension is the most common reason for physician office visits among nonpregnant adults in the United States; up to one-third of Americans over the age of 18 have been diagnosed with hypertension. Patients with physiologically significant renal artery stenosis often go unnoticed because hypertension can often be well controlled with antihypertensive medications. As a result, screening for renovascular causes of hypertension is rarely done. However, the likelihood of renovascular disease increases in patients with acute, severe, or refractory hypertension and should be explored in patients who fall into these categories. Renovascular disease is a crucial consideration in the management of hypertension due to its increasing incidence and its potential for reversibility. Although renovascular disease accounts for less than 1% of patients with mild hypertension, it is estimated that between 10 and 45% of white patients with severe or malignant hypertension have renal artery stenosis (RAS). In this population, diagnosing and treating RAS can have a profound and long-lasting effect on the treatment of hypertension.

Initial Results of Concomitant Cryoplasty After Remote Endarterectomy of the Superficial Femoral Artery: A Feasibility Study (Cryoplasty Following Remote Endarterectomy)

Objective: Remote endarterectomy is a less invasive technique compared with supragenicular bypass surgery for superficial femoral artery (SFA) occlusive disease. Early restenosis remains one of the drawbacks of this procedure. To prevent restenosis following remote endarterectomy, concomitant cryoplasty of the desobstruct SFA was introduced.

Methods: A prospective cohort study was initiated with 17 patients treated with cryoplasty of the SFA after remote endarterectomy. Indications for surgery were claudication (n = 12), rest pain (n = 3), or tissue loss (n = 2).

Results: There were no technical failures. The Kaplan-Meier estimate of the primary and assisted primary patency rate after 1 year of follow-up was 74%. Secondary patency was 89%. Limb salvage was 100%. No aneurysmal degeneration and no other adverse events occurred during the follow-up.

Conclusions: This pilot study showed that cryoplasty after remote SFA endarterectomy is a safe procedure, with promising patency rates.