An Atypical Presentation of Early Iliac Stent Failure
A 35-year-old male plumber with type 1 diabetes presents with right lower extremity and buttock claudication. He previously had undergone recanalization of an occlusion of the right external iliac artery one year prior at another institution. Duplex ultrasonography showed >75% stenosis (Figure 1a) in the right external iliac artery with a 6-fold increase in the peak systolic velocity from the distal right common iliac to proximal external iliac artery (Figure 1b and 1c). Records of the previous intervention were obtained and notable for a residual 21 mm Hg translesional systolic gradient despite aggressive balloon dilatation pre and post stent placement. He was offered a supervised exercise program but was unable to attend given full time employment. Given the imaging findings, known residual gradient and ongoing lifestyle-limiting claudication refractory to conservative measures, he was referred for invasive angiography.
Angiography performed via six French contralateral access showed fluoroscopically evident stent under-expansion correlating with a severe stenosis (Figure 2a and 2b). Despite aggressive angioplasty with a 5mm balloon at up to 24 atmospheres, significant recoil was seen. Intravascular ultrasound was performed and showed the stenosis of interest to be fibrotic material externally compressing the stent with a lack of atherosclerosis in the remainder of the vessel (Figure 3a-c).
After upsizing to 7F crossover access, balloons up to 8mm in diameter were used for high pressure angioplasty with similar results to the initial angioplasty. A 6x20mm cutting balloon was then deployed at 20 atm with sudden expansion of the balloon (Figure 4a and 4b). Following this, the patient became hypotensive, nauseous and diaphoretic. Angiography revealed a right external iliac artery perforation (Fig 4c). Balloon tamponade was performed with an 8x20mm balloon. Ipsilateral 7F access was obtained and a guidewire advanced retrograde to the aorta. An 8x38 iCAST™ stent was deployed via this access followed by further balloon tamponade with a 9mm balloon. Final angiography showed no residual extravasation (Figure 4d), and the patient's hemodynamics had returned to baseline.
What is the mechanism of target lesion failure?