Re: Televizor Stenti
Olegario Benford
Stent edge dissection (SED) is a well-known predictor of worse clinical outcomes. However, impact of SED after current-generation drug-eluting stent (DES) implantation remains unknown since there was no study using only current-generation DES to assess impact of SED. This study aimed to investigate a relationship between SED detected by optical coherence tomography (OCT) and clinical outcomes after current-generation DES implantation.
This study enrolled 175 patients receiving OCT after current-generation DES implantation. The SED group was compared with the non-SED group in terms of the primary study endpoints which was the cumulative incidence of major adverse cardiac event (MACE) composed of cardiac death, target vessel myocardial infarction (TV-MI), and clinically-driven target lesion revascularization (CD-TLR).
SED detected by OCT after the current-generation DES implantation led to unfavorable outcomes. Aggressive post-dilatation around the stent edge might worse clinical outcomes due to SED, although achievement of optimal stent expansion is strongly encouraged to improve clinical outcomes.
Copyright: 2021 Jinnouchi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Competing interests: Dr. Jinnouchi has received speaking honoraria from Abbott Vascular. Dr. Sakakura has received speaking honoraria from Abbott Vascular, Boston Scientific, Medtronic Cardiovascular, Terumo, OrbusNeich, Japan Lifeline, Kaneka, and NIPRO; he has served as a proctor for Rotablator for Boston Scientific, and he has served as a consultant for Abbott Vascular and Boston Scientific. Prof. Fujita has served as a consultant for Mehergen Group Holdings, Inc. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
Regardless of imaging modalities such as IVUS or OCT, there was no study that evaluated clinical outcomes of SED after only current-generation DES implantation. The current-generation DES has provided a different performance from bare metal stent (BMS) and first-generation DES since it improved safety and feasibility compared with BMS or first-generation DES [15, 16]. It remains unknown how SED detected by OCT affects clinical outcomes in the current-generation DES era. The purpose of this study was to investigate whether SED detected by OCT affected clinical outcomes after current-generation DES implantation.
This study was a single-center, retrospective observational study at Saitama Medical Center, Jichi Medical University. Between April 2010 and March 2020, the consecutive patients undergoing PCI were reviewed. The inclusion criteria were as follows: 1) OCT or optical frequency domain imaging (OFDI) were performed, and 2) current-generation DESs were implanted. The exclusion criteria were as follows: 1) stent was not required during the procedure, 2) BMS or first-generation DES were implanted, 3) final OCT or OFDI images after the procedures were not available, and 4) quality of images was poor to analyze. When a patient received OCT procedures more than once during the study period, only the initial procedure was included. Those patients were divided into the SED and non-SED groups according to the presence of SED detected by OCT. SED detected by OCT was defined as a disruption of the vessel luminal surface with flap at an adjacent site to the stent edge (< 5mm). The strategy of procedures was dependent on operators using OCT assessment. If necessary, the lesion preparation such as pre-dilatation, aspiration and rotational atherectomy was performed before stenting. Pre-dilatation was considered when stent underexpansion and the difficulty of device derivability were expected, or when pre-dilatation makes it easy to perform the next procedure for any reasons. Aspiration was performed when an obvious thrombus by angiography was observed, or when the effectiveness of aspiration was expected. Rotational atherectomy was required when heavily calcified lesions by angiography or intra-coronary imaging such as IVUS or OCT was observed, or unsuccessful balloon dilatation or unsuccessful balloon delivery occurred due to calcification. This study was approved by the institutional review board of Saitama Medical Center, Jichi Medical University (S20-124), and written informed consent was waived because of the retrospective study design. Follow-up data until August 2020 were obtained from a review of hospital records based on clinic visits. Saitama Medical Center, Jichi Medical University is a local core hospital. The annual average number of PCI was approximately 400 to 800 cases a year during this study-period. There are two catheter rooms and at least several interventional cardiologists performed the PCI-procedures in this hospital, although they were not consistent for this study-period from 2010 to 2020.
All OCT images were analyzed based on conventional definitions reported in expert consensus OCT documents [20, 21]. Using automated contour-detection software (OCT system, St Jude Medical or Abbott Vascular, OFDI system, Terumo), stent and lumen cross-sectional areas were measured within the stent and 5mm proximally and distally to the stent. Proximal and distal reference lumen was defined as the largest outside of the stents. In-stent lumen expansion was defined as the percentage of in-stent lumen area/ the average reference lumen area.
Proximal, distal and mean reference areas, minimal stent area, and percent expansion were not significantly different between the 2 groups (Table 2). Table 3 listed OCT data at stent edges with and without dissection. Edges with dissection showed significantly smaller reference lumen area relative to edges without dissection. Stent-oversizing index, lumen long diameter to short diameter ratio and lumen eccentricity were significantly greater in edges with dissection than without dissection. Prevalence of plaque-type at stent edge was different between edges with and without dissection. Progressive atherosclerotic plaques (i.e., lipidic and fibrocalcific plaques) were more frequently found in edges with dissection.
The main findings in this study were as follows: 1) SED detected by OCT was observed in 18.3% of cases, 2) SED detected by OCT after current-generation DES implantation was significantly associated with MACE, and 3) Risk factors for SED detected by OCT were lumen eccentricity, stent-oversizing, and progressive atherosclerotic lesion (lipidic and fibrocalcific plaques).
Our question was whether these results can be simply applied to the current-generation DES. The current-generation DES equipped with biocompatibility improved safety and efficacy as compared to first-generation DES and BMS [15, 16]. A benefit of the current-generation DES might have generated an expectation for tolerable clinical outcomes of SED cases compared with non-SED cases, which was not observed in cases after first-generation DES or BMS implantation. However, in accordance with previous OCT studies, the present study showed significantly worse clinical outcomes in the SED group than in the non-SED group after current-generation DES implantation. Therefore, our results suggest that avoiding SED would be an important strategy even in the current-generation DES era.
In this study, progressive atherosclerotic plaques, i.e, lipidic and fibrocalcific plaques, and lumen eccentricity were the risk for SED after current-generation DES implantation, which was concordant with previous reports. Several previous studies showed the factors of SED after stent implantation such as excessive stent expansion, calcified or lipidic plaques, residual plaque eccentricity, stent length, and ST-elevation MI presentation [5, 13, 24]. Stenting on significant plaque such as fibrocalcific or lipidic plaque has been a well-known determinant of SED [5, 13, 24]. In these plaques, high tensile stress is generated at the junction between tissue types with differing elastic properties [28]. In the present study, lumen eccentricity was another predictor of SED. In a lesion with large lumen eccentricity, stenting causes unequal tensile stress in the same cross-section. Higher tensile stress occurs in the direction with a shorter lumen diameter than a longer one when the stent is expanded.
The previous studies have consistently demonstrated that small minimal stent area (MSA) significantly showed worse TLR and MACE [29]. Therefore, more aggressive post-dilatation especially in vessels with small MSA might be encouraged to achieve better stent expansion [8]. However, aggressive post-dilatation around stent edges to achieve optimal stent expansion might rather have the risk of SED resulting in worse clinical outcomes. The appropriate location of post-dilatation should be carefully chosen to avoid SED. Furthermore, even if the appropriate location was selected, there would be the possibility that post-dilatation affects the unplanned location due to insufficient visibility of stent or heart beat. Therefore, it might be acceptable to choose a downsized balloon when a balloon after stent implantation is in contact with a plaque which is not protected by a stent cage.
This study showed that progressive atherosclerotic plaques (lipidic and fibrocalcific plaques) by OCT and lumen eccentricity were associated with SED. Therefore, operators have to avoid locations with these features as stent landing zones. However, even though using OCT, SED related to stent-oversizing could not be completely avoided. One of the potential reasons for SED related to stent-oversizing is that the actual stent landing zones were different from those initially planned. Those unplanned stent landing zones can be led by heart-beat, longer or shorter length of the stents than planned, or any technical mistakes. Therefore, the possibility of stent landing at unplanned zones should be considered when stent length is selected. A choice of a downsized stent is also an option to avoid SED. When it is difficult to expect the landing zone, a downsized stent can be a choice for safety. The actual landing zone would be checked by an intra-coronary imaging device after an implantation of a downsized stent, and then, the appropriate size of post-balloon should be decided to correct stent malapposition if present.
59fb9ae87f