Cryoplasty for peripheral vascular disease

Morphology of interatrial defects created by interventional techniques in a neonatal animal model

Pathological details are lacking of various techniques used for interatrial defect (IAD) creation in lesions requiring mixing or with left atrial hypertension. Therefore, the morphology of the IAD created by different interventional techniques is described. The atrial septa of ten euthanized piglets (seven at <3 days and three at 2 weeks of age) were surgically exposed. In pigs of both ages, a needle-created communication was dilated with angioplasty, cutting, and cryoplasty balloons. A stent was also implanted in a newborn pig. By way of a patent foramen ovale (PFO) in newborns, angioplasty and septostomy balloons and a stent created IADs. The morphology of the IAD was directly imaged and the size measured. Newborn piglets had noticeably thinner atrial septa, and a PFO was still present. Static balloon dilation created a circular IAD equivalent to the balloon diameter (3 and 6 mm) in both the created defects of pigs of both ages and the neonatal PFO. A 3-mm cutting balloon (CB) produced a 2-mm triangular IAD (corresponding to atherotomes) in pigs of both ages. Premounted stents, by way of a created defect or PFO, led to circular IADs equivalent to balloon diameter. The 3-mm cryoplasty balloon created a large 5 × 4-mm IAD in the newborn pig; however, the IAD measured only 2 × 1-mm at 2 weeks. By way of a neonatal PFO, a septostomy balloon (inflated to 2 cc) created a 3-mm circular IAD. In neonatal piglet hearts, static balloon angioplasty, CBs, and stents created a predictable IAD. Cryoplasty balloons created highly variable defects.

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.

Crioplastia para tratamento da doença arterial fêmoro-poplítea

CONTEXTO: O tratamento endovascular da doença arterial obstrutiva periférica apresenta baixa morbidade e mortalidade, no entanto, a perviedade dos stents a médio e longo prazo ainda é controversa. A crioplastia foi desenvolvida para reduzir os grandes desafios da angioplastia: dissecção, retração e reestenose. OBJETIVO: Avaliar os resultados clínicos e a perviedade a médio prazo em pacientes submetidos à técnica de crioplastia da doença arterial do território femoro-poplíteo. MÉTODOS: Pacientes com indicação de revascularização de membro inferior por técnica endovascular do território femoro-poplíteo, segundo as classificações clínicas de Fontaine e Rutherford e classificações anatômicas do TASC II, foram submetidos à crioplastia com cateter balão PolarCath®. No seguimento, foram avaliadas as manifestações clínicas e perviedade anatômica pelo duplex scan. RESULTADOS: Dez pacientes foram submetidos à angioplastia do território femoro-poplíteo utilizando a técnica de crioplastia. Nove pacientes apresentavam quadro clínico de claudicação limitante do membro inferior e um paciente apresentava úlcera isquêmica, três pacientes apresentavam lesão classe B pelo TASC II e sete pacientes, classe A. Sucesso técnico angiográfico inicial foi obtido em todos os casos, sendo que um caso necessitou do implante de stent devido à dissecção. Seguimento foi realizado em 9 pacientes, por período médio de 31,6 meses (28-35), com perviedade primária de 77,7% e perviedade secundária de 100%. Todos os pacientes apresentam-se assintomáticos no final do seguimento (Fontaine I). CONCLUSÕES: A crioplastia do território femoro-poplíteo é um método seguro, de baixa morbidade, com resultados a curto e médio prazo comparáveis à angioplastia convencional e com potencial de reduzir as taxas de dissecção e retração durante o procedimento, e redução do grau de reestenose a médio e longo prazo.

The use of cryoplasty in a benign ureteric stricture

Ureteral stricture is one of the most common complications following renal transplant. Current treatment options are limited to mainly surgery or balloon dilation, but mixed results and refractory cases present the opportunity for alternative treatments. Anterograde balloon cryoplasty of a benign ureteric stricture was performed in a renal transplant patient, after attempts with ballooning and stenting had failed. A 2-year follow-up demonstrates normal creatinine and no hydronephrosis on US images.

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.