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In vivo assessment of stent recoil in normal porcine arteries: Evaluation of contemporary stent designs

Acute stent recoil has been observed following balloon deflation in normal and diseased coronary arteries, and the magnitude varies by stent design. We sought to evaluate acute stent recoil in five new stents. Twenty‐five stents (four Crown, five Nir Conformer Royale, five Crossflex, five SupraG, and six GFX) were implanted in six Yorkshire pigs. All stents were expanded using a noncompliant balloon (balloon:artery ratio 1.2:1.0). Continuous ultrasound imaging was performed during stepwise balloon inflation and deflation using a 0.018″ imaging core. Maximum cross‐section areas (CSA) and minimal luminal diameter (MLD) were measured at 12 atm and immediately following balloon deflation. Maximum stent CSA matched expected balloon CSA. Area and diameter recoil were calculated as 1 − (CSAdeflation/CSAmax) and 1 − (MLDdeflation/MLDmax), respectively. Upon deflation, all stents showed recoil from maximal CSA. Area recoil was significantly lower for slotted‐tube stents than modular stents (12.6% ± 1.6% vs. 23.2 ± 3.5%; P < 0.05). In compliant, nonatherosclerotic porcine coronary arteries, acute stent recoil for the four slotted‐tube designs ranged from 8.4% to 18.0% by area. The modular stent tested was associated with significantly greater acute recoil than the slotted‐tube stents. Cathet Cardiovasc Intervent 2001;53:277–280. © 2001 Wiley‐Liss, Inc.