Cryoplasty therapy for limb salvage in patients with critical limb ischemia

An Update on Methods for Revascularization and Expansion of the TASC Lesion Classification to Include Below-the-Knee Arteries: A Supplement to the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II): The TASC Steering Comittee(.)

The Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC) guidelines were last updated in 2007 (TASC II) and represented the collaboration of international vascular specialties involved in the management of patients with peripheral arterial disease (PAD). Since the publication of TASC II, there have been innovations in endovascular revascularization strategies for patients with PAD. The intent of this publication is to provide a complete anatomic lower limb TASC lesion classification, including the infrapopliteal segment, and an updated literature review of new endovascular techniques and practice patterns employed by vascular specialists today.

An Update on Methods for Revascularization and Expansion of the TASC Lesion Classification to Include Below-the-Knee Arteries: A Supplement to the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II)

The Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC) guidelines were last updated in 2007 (TASC II) and represented the collaboration of international vascular specialties involved in the management of patients with peripheral arterial disease (PAD). Since the publication of TASC II, there have been innovations in endovascular revascularization strategies for patients with PAD. The intent of this publication is to provide a complete anatomic lower limb TASC lesion classification, including the infrapopliteal segment, and an updated literature review of new endovascular techniques and practice patterns employed by vascular specialists today.

An Update on Methods for Revascularization and Expansion of the TASC Lesion Classification to Include Below-the-Knee Arteries

The Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC) guidelines were last updated in 2007 (TASC II) and represented the collaboration of international vascular specialties involved in the management of patients with peripheral arterial disease (PAD). Since the publication of TASC II, there have been innovations in endovascular revascularization strategies for patients with PAD. The intent of this publication is to provide a complete anatomic lower limb TASC lesion classification, including the infrapopliteal segment, and an updated literature review of new endovascular techniques and practice patterns employed by vascular specialists today.

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.

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.

Critical limb ischemia: endovascular strategies for limb salvage

Critical limb ischemia (CLI) represents the most severe clinical manifestation of peripheral arterial disease, defined as the presence of chronic ischemic rest pain, ulcers, or gangrene attributable to objectively proven arterial occlusive disease. The dominant pathology underlying CLI is atherosclerosis, distributed at multiple levels along the length of the lower extremity and with a propensity for involvement of the tibial vessels in the leg and the small vessels of the foot. To achieve limb salvage in patients with CLI, revascularization of the affected limb is generally required. In contemporary practice, endovascular techniques are rapidly replacing surgical bypass as the first option for revascularization for CLI based on high technical success rates and low rates of procedure-related morbidity and mortality. This review will describe the clinical strategy of the authors who have adopted an endovascular-first approach to revascularization in treating patients with CLI and summarize the clinical outcomes of endovascular therapy in this population.

Tibial intervention for critical limb ischemia

Diagnosis and treatment of critical limb ischemia (CLI) is increasingly important as the average age of the world population and the incidence of diabetes and metabolic syndrome increases. Fortunately, most patients will not progress to this stage of peripheral arterial disease, yet if left untreated, there is a high risk of future cardiovascular events. At the point of ischemic rest pain or tissue loss, there are significant implications for morbidity and mortality. There is a high prevalence of multisegment occlusive disease in the CLI patient with the infrapopliteal vessels frequently involved. Revascularization of the affected limb is of utmost importance as the prospects of wound healing and relief of ischemic rest pain are poor without reestablishing continuous flow to the distal extremity. With the advent of endovascular devices designed to treat this vexing problem, the ability to successfully treat this difficult patient population with less procedural morbidity has been greatly enhanced.

24-carat gold, 14-carat gold, or platinum standards in the treatment of critical limb ischemia: bypass surgery or endovascular intervention?

Critical limb ischemia (CLI) remains a poorly understood, rarely reported, and inconsistently treated major global healthcare epidemic. The incidence in the US is estimated at 1% of the population aged 50 years and older and at approximately double that rate in the over-70 age group. These frequencies are expected to increase significantly with the aging population and the expected increase in diabetes. Within 1 year of being diagnosed with CLI, 40% to 50% of the now 20 million US diabetics will experience an amputation, and 20% to 25% will die. The estimate for treating CLI in the US alone is $10 to $20 billion per year, but just a 25% reduction in amputations could save $2.9 to $3.0 billion annually. Infrainguinal bypass surgery (IBS) utilizing autogenous saphenous vein has been considered the "24-carat gold standard" treatment for CLI, but over the last decade, endovascular therapy has emerged to seriously challenge IBS, which has created considerable controversy. Despite an overall lack of "hard" level I data, many interventionists are questioning the role of IBS as a first-line CLI therapy or are at least now considering IBS a "tainted" gold standard ("14-carat"). This review will examine the available evidence, but there should be no doubt regarding the huge global clinical and economic impact of CLI and amputations.

Medical and endovascular management of critical limb ischemia

Critical limb ischemia (CLI) is the term used to designate the condition in which peripheral artery disease has resulted in resting leg or foot pain or in a breakdown of the skin of the leg or foot, causing ulcers or tissue loss. If not revascularized, CLI patients are at risk for limb loss and for potentially fatal complications from the progression of gangrene and the development of sepsis. The management of CLI requires a multidisciplinary team of experts in different areas of vascular disease, from atherosclerotic risk factor management to imaging, from intervention to wound care and physical therapy. In the past decade, the most significant change in the treatment of CLI has been the increasing tendency to shift from bypass surgery to less invasive endovascular procedures as first-choice revascularization techniques, with bypass surgery then reserved as backup if appropriate. The goals of intervention for CLI include the restoration of pulsatile, inline flow to the foot to assist wound healing, the relief of rest pain, the avoidance of major amputation, preservation of mobility, and improvement of patient function and quality of life. The evaluating physician should be fully aware of all revascularization options in order to select the most appropriate intervention or combination of interventions, while taking into consideration the goals of therapy, risk-benefit ratios, patient comorbidities, and life expectancy. We discuss the incidence, risk factors, and prognosis of CLI and the clinical presentation, diagnosis, available imaging modalities, and medical management (including pain and ulcer care, pharmaceutical options, and molecular therapies targeting angiogenesis). The endovascular approaches that we review include percutaneous transluminal angioplasty (with or without adjunctive stenting); subintimal angioplasty; primary femoropopliteal and infrapopliteal deployment of bare nitinol, covered, drug-eluting, or bioabsorbable stents; cryoplasty; excimer laser-assisted angioplasty; excisional atherectomy; and cutting balloon angioplasty.

Primary cryoplasty therapy provides durable support for limb salvage in critical limb ischemia patients with infrapopliteal lesions: 12-month follow-up results from the BTK Chill Trial

PURPOSE

To report the 12-month follow-up data from the prospective 16-center Below-the-Knee (BTK) Chill Trial, which examined the use of primary cryoplasty for BTK occlusive disease in patients with critical limb ischemia (CLI).

METHODS

The trial included 108 patients (77 men; mean age 73 +/- 11 years, range 41-101) with CLI (Rutherford categories 4-6) involving 111 limbs with 115 target infrapopliteal lesions. Angiographic inclusion criteria were reference vessel diameter > or = 2.5 mm and < or = 5.0 mm and target lesion stenosis > or = 50%. The primary study endpoints were acute technical success (the ability to achieve < or = 50% residual stenosis and continuous inline flow to the foot) and absence of major amputation of the target limb at 6 months. Secondary endpoints were serious adverse events specifically related to use of primary cryoplasty and absence of major amputation of the target limb at 1, 3, and 12 months.

RESULTS

Acute technical success was achieved in 108 (97.3%) of treated limbs, with only 1 clinically significant dissection (> or = type C) and 2 residual stenoses >50%; stent placement was required following cryoplasty in only 3 (2.7%) procedures. At 6 months and 1 year, major amputation was avoided in 93.4% (85/91) and 85.2% (69/81) of patients, respectively. Through 1 year, 21% (17/81) of patients underwent target limb revascularization. Rates of major amputation and death at 1 year were 0% for limbs of patients with initial Rutherford category 4; 11.4% and 0%, respectively, for initial category 5; and 40.0% and 31.8% for initial category 6. One-year rates of major amputation and death were 20.4% and 8.8%, respectively, for diabetics, versus 4.0% and 10.7% for non-diabetics. At 1 year, major amputation occurred in 16.7% (2/12) of limbs that were expected to be amputated at the time of treatment.

CONCLUSION

Cryoplasty therapy is a safe and effective method of treating infrapopliteal disease, providing excellent results and a high rate of limb salvage in patients with CLI. Study outcomes through 1 year support the use of cryoplasty as a primary treatment option for patients with CLI secondary to BTK occlusive disease.

Midterm outcome predictors for lower extremity atherectomy procedures

PURPOSE

The performance of atherectomy devices has been variable. The purpose of this study was to evaluate our experience using the SilverHawk atherectomy (Fox Hollow Technologies, Redwood City, Calif) device for lower extremity procedures to determine predictors of midterm success.

METHODS

Records of all patients who underwent lower extremity atherectomy with the SilverHawk atherectomy catheter were reviewed. Patient demographics, vessel treated, number of vessels treated, lesion characteristics, and postoperative courses were analyzed. Cumulative patency rates, limb salvage, mortality, and factors associated with outcomes were determined using the Kaplan-Meier Method with Cox Proportional Hazards modeling.

RESULTS

Between January 2004 and January 2006, 167 vessels were atherectomized with the SilverHawk in 73 patients. There were 42 men and 31 women treated, and the mean age was 68.8 +/- 13.8. Five patients had both legs treated for a total of 78 legs treated. Of the 78 legs intervened on, 25.6% (20/78) had 1 vessel treated, 51.3% (40/78) had 2 vessels treated, 11.5% (9/78) had 3 vessels treated, 9% (7/78) had 4 vessels treated, and 2.6% (2/78) had 5 vessels treated. A total of 78% (61/78) of patients had intermittent claudication, 71% (56/78) had rest pain, and 58% (45/78) had tissue loss. Adjunctive procedures were performed in 63 vessels in 33 patients (61 percutaneous transluminal angioplasty [PTA] and 2 PTA + stent). Eighty-four vessels treated were totally occluded and 83 stenotic. Cumulative 1-year primary, primary assisted, secondary patency, limb salvage, and survival rates with confidence intervals, respectively, are: 43% (30,57), 49% (36,63), 57% (43,71), 75% (57,92), and 90% (80,100). Multivariable analysis demonstrated tobacco use, renal disease, diabetes, and tissue loss are all predictors of patency loss, while only diabetes and tissue loss were associated with greater limb loss. There was no difference in patency rates irrespective of location of Trans Atlantic Inter-Societal Consensus (TASC) classification, vessel treated (femoral vs tibial), or degree of stenosis (occluded vs stenotic). Also, multiple vessels treated in the same patients had no affect on patency. The mean ankle brachial index (ABI) pre-op was 0.57 +/- 0.19, and this increased to 0.81 +/- 0.21 (P < .001) at 30 days post-op.

CONCLUSION

Lower extremity atherectomy procedures with the SilverHawk device are safe and effective means in improving symptoms. However, there is decreased durability and significant patency and limb loss over time. Diabetes, renal disease, tobacco use, and tissue loss are all associated with inferior outcomes.