Stent Fracture and Longitudinal Compression on CT Angiography between the

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1 2014 ASCI Stent Fracture and Longitudinal Compression on CT Angiography between the First- and New-Generation Drug-Eluting Stent Mi Sun Chung, Dong Hyun Yang,Young-Hak Kim, Jae-Hyung Roh, Joon-Won Kang, Seung-Jung Park, Tae-Hwan Lim et al. Department of Radiology, Division of Cardiology, Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

2 Coronary Stent Fracture Relatively High Incidence Incidence of stent fracture : % Potential Cause of in-stent restenosis (ISR) 20% of the patients with DES ISR have stent fractures Shaikh F, et al. Catheter Cardiovasc Interv 2008;71:614 8 CTA depicts more stent fractures than CAG 16.9% by CTA vs. 1.0% by CAG Hecht HS et al. J Am Coll Cardiol 2009;54: Stent Fracture

3 Definition Longitudinal Compression Distortion or shortening of a stent in the longitudinal axis following successful stent deployment Williams, et al. EuroIntervention, 2012;8: New generation drug-eluting stents (DES) Lower longitudinal strength due to thin strut Longitudinal Compression The incidence and clinical significance of longitudinal compression remained unclear

4 Purpose To evaluate the incidence and clinical impact of stent fracture, longitudinal compression and in-stent restenosis after 1 st - and new generation drug-eluting stent (DES) implantation using CT coronary angiography

5 Subjects Coronary CT angiography of patients with coronary stent 636 patients May 2011 ~ Feb 2013 Exclusion criteria - No matched coronary angiography (N=188) - Subjects treated with BMS (n=74) 374 patients 1 st generation DES : 235 pts with 368 stents New generation DES : 139 pts with 234 stents

6 Coronary CTA Imaging Criteria Stent fracture - Partial or circumferential separation of the stent on visual inspection of CT image using Maximal intensity projection (MIP) or curved planar reformation technique (CPR) - Absence of a metallic strut on cross-sectional image Absence of strut Normal strut CPR image MIP image Cross sectional images

7 Coronary CTA Imaging Criteria Longitudinal compression - Uneven distortion or shortening of a stent in the longitudinal axis - Increased density of a strut in a shorted area

8 Longitudinal Compression: Phantom validation Resolute Integrity, 3.5 mm CT Cross sectional image Angiography CT Micro-CT

9 Case 1 Case 1 Stent Fracture and ISR 58 yrs/m with chest pain PCI at prca (Cypher) (2006) Stent fracture causing total occlusion Total occlusion of prca stent was confirmed by angiography _Sudden loss of stent strut _Low density filling defect in stent

10 Case 2 Longitudinal compression 65 yrs/m PCI at LM-pLAD (Xience prime) ( ) Longitudinal Compression _osteal lesion CAG (Xience prime) CT _Uneven distortion or shortening of stent in longitudinal axis _Increased density of strut in shorted area

11 Statistical analysis First- vs. new-generation DES - Pateints demographics - Procedural finding - CTA findings Contingency table between stent fx or longitudinal compression and predisposing factors Morphologic factors of stent Clinical factors Clinical outcomes Kaplan-Mayer curve Log-rank test to compare the difference in clinical outcomes

12 Baseline Clinical Characteristics Variables 1 st generation DES New generation DES (N=235 patients) (N=139 patients) p value Age, years 60.8 ± 10.2 (34~89) 59.3 ± 10.9 (31~83) 0.19 Male, n (%) 190 (80.9) 105 (75.5) 0.24 BMI (kg/m 2 ) 25.1 ± 2.7 (17.2 ~33.3) 25.1 ± 2.7 (18.9 ~32.1) 0.85 Index diagnosis, n (%) Stable angina 151 (64.3) 83 (59.7) 0.44 Unstable angina 40 (17.0) 33 (23.7) 0.14 Non STEMI 9 (3.8) 8 (5.8) 0.44 STEMI 35 (14.9) 15 (10.8) 0.28 DM, n (%) 65 (27.7) 42 (30.2) 0.64 HTN, n (%) 137 (58.3) 70 (50.4) 0.16 Hyperlipidemia, n (%) 59 (25.1) 66 (47.5) <0.001 Renal failure, n (%) 1 (0.4) 3(2.2) 0.15 Smoking, n (%) 96 (40.9) 51 (36.7) 0.45 LVEF (%) 59.8 ± 7.6 (32.0~79.0) 60.0 ± 6.4 (36.0~72.0) 0.88

13 Baseline procedural Characteristics Variables 1 st generation DES New generation DES (N=322 stents) (N=213 stents) p value CT findings Long stent 80 (24.8) 60 (28.2) 0.42 Stent overlap 59 (18.3) 48 (44.9) 0.27 Stent in proximal artery 216 (67.1) 150 (70.4) 0.45 Os lesion 18 (5.6) 20 (9.4) 0.12 Stent in excessive tortoursity 22 (6.8) 22 (10.3) 0.15 Underexpansion of stent 19 (5.9) 14 (6.6) 0.86 Angiographic findings Target coronary artery, n (%) LM 18 (7.7) 38 (27.3) < LAD 195 (83.0) 112 (80.6) 0.58 LCX 74 (31.5) 53 (38.1) 0.21 RCA 102 (43.4) 63 (45.3) 0.75 Stent diameter (mm) 3.27 ± ± Total stent length (mm) ± ± Number of stents 1.71 ± ±

14 Incidence of Fracture, Longitudinal Compression, and In-Stent Restenosis on CT * CTA detected more stent fracture (9.3% vs. 2.3%) and longitudinal compression (2.3% vs. 0.6%) than angiography, respectively. 1 st generation DES (N=322 stents) New generation DES (N=213 stents) p value Stent fracture 26 (8.1) 24 (11.3) 0.23 Longitudinal compression 1 (0.3) 13 (6.1) < ISR 14 (4.3) 3 (1.4) 0.08

15 30 Incidence of Fracture, Longitudinal Compression and ISR on CT according to Stent Type Cypher (n=287) Taxus (n=35) Promus (n=4) Xience or Xience V (n=68) Endeavor (n=68) Resolute (n=16) Xience prime (n=16) Stent fracture Longitudinal compression ISR Promus element (n = 26) Novori or Biomatrix (n=15)

16 Predisposing factors and stent fracture /longitudinal compression Stent fracture - Longer stent (39 mm vs. 33 mm; p=0.001) - Excessive tortuosity of the stent (25% vs. 8%; p=0.001) - Younger patients (56 yrs vs. 61 yrs; p=0.003) - Stent location (LAD, RCA; p=0.004) Longitudinal compression - Ostial stenting (21.6% vs. 1.2 %; p<0.001) - Stent location (Left main coronary artery; p<0.001)

17 Clinical outcomes of the patients with 1 st and New generation DES Outcomes 1 st generation DES (N=235 patients) New generation DES (N=139 patients) Fracture or compression Yes (n=23) No (n=212) P value * Yes (n=30) No (n=109) P value * Months 75.3 ± ± ± ± 20.8 Death n (%) 0 1 (0.01) (0.01) 0.60 Cardiac (0.01) 0.60 Non-cardiac 0 1 (0.01) MI, n (%) 0 2 (0.01) TVR, n (%) 3 (0.16) 18 (0.15) (0.03) 4 (0.04) 0.94 MACE, n(%) 3 (0.16) 20 (0.16) (0.03) 5 (0.05) 0.77

18 Conclusions Coronary CTA can evaluate stent fracture and longitudinal compression, in first- and new-generation DES with higher conspicuity than CAG. The risk of longitudinal compression was higher for new-generation DES than for old-generation DES due to thinner struts and fewer connectors. However, fortunately, stent fracture or longitudinal compression did not translate into worse clinical outcomes.

19 Thank you!