title: 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.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Cardiology & Interventional Vascular Associates, Presbyterian Heart Institute, 7150 Greenville Avenue, Suite 500, Dallas, TX 75231, USA. Tdas@civadallas.com
authors.forename: Tony S
authors.initials: TS
authors.lastname: Das
authors.forename: Thomas
authors.initials: T
authors.lastname: McNamara
authors.forename: Bruce
authors.initials: B
authors.lastname: Gray
authors.forename: Gino J
authors.initials: GJ
authors.lastname: Sedillo
authors.forename: Brian R
authors.initials: BR
authors.lastname: Turley
authors.forename: Kenneth
authors.initials: K
authors.lastname: Kollmeyer
authors.forename: Michael
authors.initials: M
authors.lastname: Rogoff
authors.forename: John E
authors.initials: JE
authors.lastname: Aruny
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical; D000800:Angioplasty, Balloon / Q000009:adverse effects; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D003251:Constriction, Pathologic; D016638:Critical Illness; D017679:Cryotherapy / Q000009:adverse effects; D006801:Humans; D007511:Ischemia / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D007866:Leg / Q000098:blood supply*; D023821:Limb Salvage; D008297:Male; D008875:Middle Aged; D011150:Popliteal Artery / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011859:Radiography; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States