Transcatheter interventions for the treatment of peripheral atherosclerotic lesions: part II

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.

Stent-Assisted Angioplasty at the Level of the Common Femoral Artery Bifurcation:Midterm Outcomes

PURPOSE

To report the midterm outcome after stent-assisted angioplasty of occlusive disease at the common femoral artery bifurcation.

METHODS

Between 1995 and 2002, 27 consecutive patients (18 men; mean age 70 years, range 47-90) underwent angioplasty with stent implantation in 33 limbs; target sites included 19 common femoral arteries, the origins of 2 superficial or 4 profunda femoris arteries, and 8 bypass anastomoses.

RESULTS

Technical success was 100%. Patients were followed for a mean 30 months (95% CI 21 to 39), at which time the cumulative primary patency was 86% (95% CI 85% to 88%). At 3 years, 83% of the arteries were patent. Five restenoses were due to neointimal hyperplasia in 4 cases (3 bypass grafts) and strut failure of the only balloon-expandable stent used in this series. Restenoses due to neointimal hyperplasia at bypass anastomoses (3/ 8) were more common than in native arteries (2/25) (p=0.078); cumulative primary patency for the bypass subgroup was 71% (95% CI 59% to 82%) at a mean 23-month follow-up; 75% and 60% of the anastomoses were patent after 1 and 2 years, respectively.

CONCLUSIONS

Angioplasty of obstructions in the common femoral artery and its bifurcation with implantation of self-expanding stents shows good midterm primary patency. Native artery lesions have a better outcome than stenoses at bypass anastomoses. The procedure does not preclude further endovascular interventions at the puncture site.

Novel growth stent for the permanent treatment of vessel stenosis in growing children: An experimental study

Stent implantation in stenotic vessels of infants and small children is problematic because there is no ideal stent model that is small enough to be easily introduced into the infant femoral vein or artery and, at the same time, large enough to be dilated during growth to adult vessel diameters. To overcome this problem, we designed a new stent, the growth stent. This growth stent is a balloon-expandable metal stent. Two longitudinal halves are connected with bioabsorbable sutures so that a circular stent is created. It was postulated that after absorption of the sutures the stent would not impede growth. Twenty of these stents were implanted in the aorta, pulmonary arteries, and inferior vena cava of piglets (average weight 6.9 kg). After 18 weeks (14-23 weeks) and a mean weight gain of 59 kg, none of the stented vessels showed any significant stenosis or pressure gradient, documented by angiography and catheter pullback. During fluoroscopy, the two halves of the stent were clearly separated in all animals. The growth stent has the potential to be nonrestrictive during vessel growth, and thus is a promising new device for the permanent treatment of stenotic vessels in infancy and childhood.

Optimal therapeutic approaches to femoropopliteal artery intervention

Superficial femoral artery disease presents a complex challenge for therapy. The extent of vascular involvement may vary from focal disease with symptoms of intermittent claudication to long total occlusions manifest as critical limb ischemia. Optimal therapy requires understanding the available options including exercise programs, pharmacologic medical therapy, surgery and interventional endovascular therapy. Rapidly advancing endovascular technology for enabling safe intervention in complex, long occlusive segments of the superficial femoral artery continues to emerge. New devices like the SafeCross wire, Excimer laser, Silverhawk Atherectomy catheter, Cryoplasty catheter and new generations of bare metal and drug-eluting nitinol stents are shifting the paradigm for therapy from surgical to more endovascular treatment even for the most complex disease presentation.