Cryoplasty for peripheral vascular disease
Abstract
Background
In the UK, symptomatic peripheral arterial disease (PAD) occurs in 5 to 7% of people over the age of 55 years. Cryoplasty offers a new approach by combining the dilation force of balloon angioplasty with the delivery of cold thermal energy to the vessel wall. Cryoplasty is thought to provoke apoptosis rather than necrosis in the arterial smooth muscle cells and thus has the theoretical advantage of reduced myointimal hyperplasia in long‐term patency.
As it is an emerging therapy, safety and efficacy questions remain. This systematic review evaluates the treatment and provide focus for further research in the field.
Objectives
To assess the efficacy of, and complications associated with, cryoplasty for maintaining patency in the iliac or infrainguinal arteries.
Search methods
For this update the Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched 17 July 2009) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library last searched 2009, Issue 3.
Selection criteria
Trials in which patients with peripheral arterial disease (PAD) of the iliac or infrainguinal arteries were randomised to cryoplasty with or without another procedure versus a procedure without cryoplasty. This includes trials where all patients receive angioplasty and the randomisation is for cryoplasty versus none.
Data collection and analysis
Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author. As no randomised controlled trials of cryoplasty were found, no statistical analyses were performed.
Main results
No randomised controlled trials of cryoplasty were identified.
Authors' conclusions
The benefit of cryoplasty over conventional angioplasty has not been established as no randomised controlled trials exist to properly evaluate this method. Technical success and primary patency rates seen in the prospective series are encouraging and may suggest a future role for cryoplasty in the treatment of PAD, but cannot be reliably interpreted due to the nature of the studies.
PICOs
Plain language summary
Cryoplasty for peripheral vascular disease
Peripheral arterial disease results from narrowing of the main arteries to the legs because of atherosclerosis, which limits the supply of nutrients to the muscles and other tissues. The shortage of blood flow caused by a blocked artery can become so severe that a limb is threatened (critical limb ischaemia) and surgery is required. Endovascular surgery involves inserting a small balloon into the affected artery. The balloon is inflated to break up the atheromatous plaque, stretch the smooth muscle cells within the middle of the vessel wall and widen the arterial lumen (called percutaneous balloon angioplasty). Unfortunately the artery often narrows again over time (restenosis). Cryoplasty applies cold to the vessel wall at the same time as using the dilation force of balloon angioplasty and may reduce thickening of the inner muscular layer of the blood vessel to improve long‐term angioplasty results.
The benefit of cryoplasty over conventional angioplasty has not been established as no randomised controlled trials exist to properly evaluate this new method. The technical success and rates of unobstructed arteries (primary patency) seen in six case series are encouraging and suggest a future role for cryoplasty in the treatment of peripheral arterial disease. The long‐term outcomes are as yet unknown.
