Cross-Sectional and Longitudinal Positive Remodeling After Subintimal Drug-Eluting Stent ImplantationMultiple Late Coronary Aneurysms, Stent Fractures, and a Newly Formed Stent Gap Between Previously Overlapped Stents
Kenichi Tsujita, MD, PhD*,
Akiko Maehara, MD*,*,
Gary S. Mintz, MD*,
Michael Poon, MD*,
Giuseppe Maiolino, MD, PhD*,
Teppei Sugaya, MD ,
Keiichi Igarashi, MD, PhD,
Masahiko Ochiai, MD, PhD
* Cardiovascular Research Foundation, New York, New York
Hokkaido Social Insurance Hospital, Sapporo, Japan
Showa University Northern Yokohama Hospital, Yokohama, Japan
A 50-year-old man with a history of smoking and hyperlipidemia, but no chest pain, was admitted because of an abnormal electrocardiogram and regional wall motion abnormality on echocardiography (mild inferior hypokinesis). Coronary angiography revealed 2 chronic total occlusions (CTOs): ostial right coronary artery (RCA) and mid left circumflex artery. The long RCA CTO lesion was treated by intentional, retrograde creation of a subintimal lumen with a "knuckled" Fielder XT wire (Asahi Intecc, Nagoya, Japan) (Fig. 1) followed by deliberate implantation of 4 overlapping paclitaxel-eluting stents into the subintimal space. Complete stent-vessel wall apposition and overlapping of adjacent stents was confirmed by post-procedural intravascular ultrasound (Figs. 2 and 3). The 8-month follow-up coronary angiogram showed multiple aneurysms in the RCA, but not in the mid left circumflex artery that had been treated using a conventional antegrade CTO approach and single stent implantation into the true lumen. At the sites of the RCA aneurysms, intravascular ultrasound demonstrated large areas of late acquired stent malapposition (LSM) due to vessel remodeling (an increase in cross-sectional and longitudinal vessel dimensions), changes that were most marked at the sites of subintimal stent implantation (Fig. 2). These areas of LSM were accompanied by stent fractures as well as a newly formed gap between the (previously overlapped) most distal stent and the proximal adjacent partial stent segment (Fig. 3). Serial intravascular ultrasound quantitative analysis revealed positive remodeling (increase in mean vessel area from 15.0 to 20.8 mm2). The newly formed gap between previously overlapped stents suggested that positive vessel remodeling occurred in the longitudinal direction as well as cross-sectionally.
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Figure 1 Baseline Coronary Angiogram and Subintimal Wiring
(A) An extremely long chronic total occlusion (CTO) from the ostium of the right coronary artery (RCA) to the distal bifurcation (arrowheads) was seen in the pre-interventional angiogram. The contralateral injection showed an epicardial collateral from left anterior descending coronary artery to the RCA. (B) The CTO was successfully crossed using a retrograde approach via this epicardial collateral combined with the intentional creation of subintimal lumen using a stiff guidewire. Coronary angiography showed a large coronary dissection in the proximal RCA. (C) The intravascular ultrasound catheter (white arrow in B) was placed in the subintimal space, and the true lumen was collapsed at the 2-o'clock position.
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Figure 2 Cross-Sectional Positive Remodeling
The index and follow-up angiograms (left) after 4 overlapping paclitaxel-eluting stents (2.75 x 32 mm, 3.0 x 32 mm, 3.0 x 32 mm, and 3.5 x 28 mm) were implanted from the distal bifurcation to orifice of the RCA to treat a long CTO lesion. The dashed line indicates the subintimal stents; the 4 double-headed white arrows indicate the location of each of the 4 stents. The follow-up angiogram demonstrated multiple aneurysms especially in the proximal segment where a large dissection was observed at the index procedure. Cross-sectional and longitudinal IVUS panels (A) correspond to A on the baseline angiogram; cross-sectional and longitudinal IVUS panels (A') correspond to A' on the follow-up angiogram. The baseline and follow-up cross-sectional IVUS images are from the same anatomic location(s) in the RCA; note the small right ventricular branch at the 1-to-2-o'clock position on the baseline and follow-up images that corresponds to the same small right ventricular branch on the angiograms. At baseline, both the cross-sectional and longitudinal IVUS images (A) showed well-apposed and well-expanded stents. At follow-up (A'), there were large areas of late acquired stent malapposition (LSM) due to positive vessel remodeling (white arrowheads) on both the cross-sectional and longitudinal IVUS images. Abbreviations as in Figure 1.
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Figure 3 Longitudinal Positive Remodeling
The index and follow-up angiograms (top, left, and center) after 4 paclitaxel-eluting stents (2.75 x 32 mm, 3.0 x 32 mm, 3.0 x 32 mm, and 3.5 x 28 mm) were implanted from the distal bifurcation to orifice of the RCA to treat a long CTO lesion. Unlike Figure 2, here we focus on segments B/B' and C/C'; note that at follow-up, both locations contain fluoroscopic evidence of absence of stent struts indicating either fracture (B') or separation of overlapped stents (C'). The IVUS sequences B and B' are from the same anatomic location in the RCA and correspond to B on baseline and follow-up angiograms; IVUS sequences C and C' are from the same anatomic location in the RCA and correspond to C on baseline and follow-up angiograms. In IVUS sequences B-B' from baseline to follow-up, there has been positive remodeling (white arrowheads), development of LSM (asterisks), and stent fracture (absence of stent struts in the middle IVUS image). In IVUS sequences C-C' from baseline to follow-up, there developed an absence of stent struts at the site of previously overlapping stents (small white arrows, double stent layers at baseline, but no struts at follow-up in the middle IVUS image). The follow-up 64-slice multidetector computed tomography (MDCT) of the RCA confirmed the IVUS findings of complete (B') stent fracture and separation of the previously overlapped stents (C'). The MDCT image showed 2 additional areas of incomplete (D) and complete (E) stent fracture; these were also seen on the IVUS studies, but are not included here for the sake of simplicity. Abbreviations as in Figures 1 and 2.
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Drug-eluting stents reduce restenosis even after treatment of CTO lesions. However, the frequency of LSM appears to be greater after the implantation of drug-eluting stents versus bare metal stents and especially in the setting of treatment of CTO lesions; Hong et al. (1) reported that predictors of LSM were total stent length, primary stenting in acute myocardial infarction, and stenting of CTO lesions. Hong et al. (1,2) found that LSM may be associated with less neointimal hyperplasia, but it has also been implicated in patients with very late stent thrombosis (3). In the current case, large areas of LSM were observed at the sites of angiographic aneurysms that were detected 8 months after treatment of an RCA CTO. The complex procedure included deliberate subintimal passage of the guidewire and implantation of drug-eluting stent into the subintimal space. This technique might have exaggerated injury to the medial and adventitial layers; or the adventitial location of the drug and polymer may have induced a local hypersensitivity to cause cross-sectional and longitudinal vessel remodeling, LSM, and aneurysm formation. Of note, there were no areas of aneurysm formation or LSM 16 months after treatment of the left circumflex artery CTO using a conventional antegrade approach with sirolimus-eluting stent implantation into the true lumen.
* Reprint requests and correspondence: Dr. Akiko Maehara, Cardiovascular Research Foundation, 111E 59th Street, New York, New York 10022 (Email: amaehara{at}crf.org).
Manuscript received October 10, 2008;
accepted November 2, 2008.
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REFERENCES
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- Hong MK, Mintz GS, Lee CW, et al. Late stent malapposition after drug-eluting stent implantation: an intravascular ultrasound analysis with long-term follow-up Circulation 2006;113:414-419.[Abstract/Free Full Text]
- Hong MK, Mintz GS, Lee CW, et al. Incidence, mechanism, predictors, and long-term prognosis of late stent malapposition after bare-metal stent implantation Circulation 2004;109:881-886.[Abstract/Free Full Text]
- Cook S, Wenaweser P, Togni M, et al. Incomplete stent apposition and very late stent thrombosis after drug-eluting stent implantation Circulation 2007;115:2426-2434.[Abstract/Free Full Text]
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