Changes in arterial wall compliance after endovascular stenting

Area of Science:

• Vascular biology
• Biomedical engineering
• Interventional cardiology

Background:

• The arterial wall's response to endovascular stenting post-angioplasty is not fully understood.
• In situ changes in the elastic properties of stented vessels remain largely unknown.

Purpose of the Study:

• To investigate vascular compliance in canine iliac arteries before and after intravascular ultrasound-guided self-expandable metallic stent deployment.
• To assess the in situ elastic properties of stented arteries over time.

Main Methods:

• Vascular compliance was measured in 11 normal canine iliac arteries using an absolute induction angiometer.
• Measurements were taken before stenting, immediately after, and at 1, 2, and 4 weeks post-deployment in nine animals.
• The angiometer utilized a catheter-based wire loop probe to measure diameter changes induced by systolic/diastolic pressure variations.

Main Results:

• Mean arterial compliance decreased from 4.4 +/- 2.1 to 1.9 +/- 2.0 (x 10(-2) diameter %/mm Hg) immediately after stenting.
• Stented arteries showed reduced expansile properties and became noncompliant as early as 1 week post-deployment.
• Diminished compliance correlated with a periadventitial fibrous reaction; neointimal hyperplasia was present but did not obstruct flow, and all vessels remained patent.

Conclusions:

• The inherent flexibility of radially compliant stents is lost relatively quickly after implantation in nonatherosclerotic canine arteries.
• A significant periadventitial fibrous reaction contributes to the loss of vascular compliance post-stenting.
• Despite neointimal hyperplasia, stented iliac arteries remained patent without thrombus formation.