Stent expansion: a combination of delivery balloon underexpansion and acute stent recoil reduces predicted stent diameter irrespective of reference vessel size

Abstract

Background: There is a strong inverse relationship between final vessel diameter and subsequent risk of treatment failure after coronary stent deployment. The aim of this study was to investigate the magnitude by which stent delivery balloon underexpansion and stent elastic recoil contributed to suboptimal final vessel geometry. Methods: A prospective angiographic study recruiting 499 lesions (385 patients) undergoing coronary stent implantation was performed. Quantitative coronary angiography (QCA) was used to measure the minimal lumen diameters of the delivery balloon during stent deployment (MLD1) and of the stented segment following balloon deflation (MLD2). The expected balloon diameter for the deployment pressure was determined from the manufacturer's reference chart. Delivery balloon deficit was measured by subtracting the MLD1 from the expected balloon size and stent recoil was calculated by subtracting MLD2 from MLD1. Delivery balloon deficit and stent recoil were examined as a function of reference vessel diameter (RVD) and balloon-vessel (BV) ratio. Results: The final stent MLD was a mean 27.2% (SD = 7.2) less than the predicted diameter. The mean delivery balloon deficit was 0.65 mm (SD = 0.27) and the mean stent recoil was 0.28 mm (SD = 0.17). Percentage delivery balloon deficit and stent recoil were independent of RVD. Delivery balloon deficit increased with higher BV ratios. Stent recoil was independent of BV ratio and the use of predilatation. Conclusion: Failure to achieve predicted final stent diameter is a real problem with contribution from delivery balloon underexpansion and stent recoil. On average the final stent MLD is only 73% of the expected diameter, irrespective of vessel size.

Incidence, predictive factors and haemodynamic consequences of acute stent recoil following transcatheter aortic valve implantation with a balloon-expandable valve

“…Interestingly, the 29 mm valve exhibited a higher degree of absolute recoil than the 23 mm prosthesis, but the relative recoil was similar among valve sizes. This is in accordance with coronary stent studies, where the relative recoil was not influenced by the reference vessel and stent diameters 16 . r=0.14 p=0.21 …”

“…These data could have implications for selecting the Taking this a step further, the present study was the first to assess the dynamic performance of a balloon-expandable valve during the implantation process, showing that some decrease in stent dimensions occurs almost systematically after balloon deflation and contributes to the failure to achieve predicted final stent dimensions. In previous coronary studies, the percentage of stent recoil was about 6% (ranging from 3 to 18%) as measured by quantitative coronary angiography 2,[16][17][18] , which is close to the degree of recoil observed in the present study. Importantly, the degree of acute relative recoil was comparable across the three levels of the valve stent frame, highlighting the fact that the elastic behaviour is homogenous in the entire prosthesis.…”

3-Year Clinical Outcome of Patients With Chronic Total Occlusion Treated With Drug-Eluting Stents

“…The extension of the disease increases the possibility of sites of incomplete stent expansion, increasing the risk for restenosis and re-intervention. Final minimal lumen diameter and residual stenosis are influenced by many factors that might provoke inadequate stent expansion (21): vessel resistance, stent dimensions, delivery pressure inflations, stent recoil, and use of noncompliant balloons. Small final minimal lumen diameters and high residual stenosis percentage might contribute to restenosis and consequent TLR.…”

Fatigue life assessment of cardiovascular balloon-expandable stents: A two-scale plasticity–damage model approach

“…The balloon expansion drives the stent expansion leading to plastic deformation providing a permanently expanded state. Clearly, a certain level of elastic recoil occurs on deflation and removal of the balloon (Aziz et al, 2007).…”