Coronary Evaginations Research Articles

The Usefulness of Intracoronary Imaging in Patients with ST-Segment Elevation Myocardial Infarction.

Intracoronary imaging (ICI) modalities, namely intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have shown to be able to reduce major adverse cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). Nevertheless, patients with ST-segment elevation myocardial infarction (STEMI) have been practically excluded from contemporary large randomized controlled trials. The available data are limited and derive mostly from observational studies. Nevertheless, contemporary studies are in favor of ICI utilization in patients who undergo primary PCI. Regarding technical aspects of PCI, ICI has been associated with the implantation of larger stent diameters, higher balloon inflations and lower residual in-stent stenosis post-PCI. OCT, although used significantly less often than IVUS, is a useful tool in the context of myocardial infarction without obstructive coronary artery disease since, due to its high spatial resolution, it can identify the underlying mechanism of STEMI, and, thus, guide therapy. Stent thrombosis (ST) is a rare, albeit a potential lethal, complication that is expressed clinically as STEMI in the vast majority of cases. Use of ICI is encouraged with current guidelines in order to discriminate the mechanism of ST among stent malapposition, underexpansion, uncovered stent struts, edge dissections, ruptured neoatherosclerotic lesions and coronary evaginations. Finally, ICI has been proposed as a tool to facilitate stent deferring during primary PCI based on culprit lesion characteristics.

Early coronary healing in ST segment elevation myocardial infarction: sirolimus-eluting stents vs. drug-coated balloons after bare-metal stents. The PEBSI-2 optical coherence tomography randomized study.

Drug-coated balloons (DCBs) have theoretical advantages over drug-eluting stents (DESs) to facilitate stent healing. We studied whether, in patients undergoing primary coronary interventions (pPCIs), a strategy of DCB after bare-metal stent improves early healing as determined by optical coherence tomography (OCT) compared with new-generation DES. pPCI patients were randomized (1:1) to treatment with new-generation sirolimus-eluting stents (DES group) or DCB-strategy. Vessel healing was assessed by OCT at 90 days. Fifty-three patients were randomized (26 DES vs. 27 DCB). At 90 days, both strategies showed a low rate of uncovered struts (3.2 vs. 3.2%, P = 0.64) and a very high and similar rate of covered and apposed struts (96.6 vs. 96.1%, respectively; P = 0.58). However, DCB group had a significantly lower rate of major coronary evaginations (68 vs. 37%, P = 0.026), and more frequently developed a thin homogeneous neointimal layer (20 vs. 70.4%, P = 0.001) suggesting distinct superior healing at 3 months compared to DES. In pPCI both, sirolimus-DES and DCB-strategy, provide excellent strut coverage at 3 months. However, DCB ensures more advanced and optimal stent healing compared to sirolimus-DES. Further research is needed to determine whether, in patients undergoing pPCI, DCB offers superior long-term clinical and angiographic outcomes than new-generation DES (NCT03610347).

Optical coherence tomography assessment of coronary stents 5 years after implantation for ST-elevation myocardial infraction

Background. Main causes of very late stent thrombosis are neoatherosclerosis, late malapposition and the presence of uncovered struts. However, it remains unclear how often the above-described pathological changes are determined in stable patients without adverse cardiac events.Aim. In the present study we aimed to perform optical coherence tomography (OCT) assessment of coronary stents 5 years after implantation for ST-elevation myocardial infarction.Methods. Among 194 patients included in the hospital “Prospective PCI Registry” from October 2012 to November 2013, 25 patients were enrolled in the study. All patients received OCT, median time was 66 [63.0; 72.5] months. Only stable patients without adverse cardiac events during follow-up were included in the study. The optimal condition of the coronary stents was determined in the absence of uncovered and malapposed struts, restenosis (more than 50 % of the artery diameter), signs of neoatherosclerosis and thrombus.Results. Based on OCT results, two groups were identified. The first group consisted of 9 patients (36 %) with optimal stent condition. The comparison group included 16 patients with suboptimal condition of the coronary stents. At the same time 13 patients of this group had uncovered struts, 9 — malapposed struts, 8 had both uncovered and malapposed struts, 7 patients had neoatherosclerosis, 3 patients had restenosis of more than 50 % of the vessel diameter, 1 patient — thrombus in the stented segment, 4 patients — coronary evaginations. Uncovered struts were more often found in the proximal and middle segments of the stents, while malapposed struts in the middle segments of the stents. There was direct correlation between the percent of uncovered and malapposed struts (r = 0.544; р = 0.005), percent of uncovered struts and malapposition length (r = 0.601; р = 0.002), percent of uncovered struts and maximum distance of malposition (r = 0.574; р = 0.003). The incidence of neoatherosclerosis was associated with increase in the length stents (odds ratio = 1.15, 95% CI 1.01–1.31, p = 0.039).Conclusion. In most patients, stent condition was suboptimal 5 years after implantation for STEMI. Neoatherosclerosis, malapposition and uncoated struts were the main reasons for suboptimal stent condition. Received 16 September 2020. Revised 9 October 2020. Accepted 12 October 2020. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest. Author contributionsConception and design: I.S. BessonovDrafting the article: I.S. Bessonov, A.O. Dyakova, A.I. Kostousova, S.S. Sapoznikov, E.A. GorbatenkoCritical revision of the article: V.A. Kuznetsov, E.A. GorbatenkoFinal approval of the version to be published: I.S. Bessonov, V.A. Kuznetsov, A.O. Dyakova, A.I. Kostousova, S.S. Sapoznikov, E.A. Gorbatenko

Relevance of coronary evaginations in bioresorbable vascular scaffolds

Relevance of coronary evaginations in bioresorbable vascular scaffolds

Major coronary evaginations following implantation of bioresorbable vascular scaffolds – Clinical and OCT characteristics

Coronary evaginations can occur after implantation of bioresorbable vascular scaffolds (BRS) and may be associated with scaffold thrombosis. Aim of this study was to clarify the clinical manifestation, extent and time course of coronary artery remodeling in vessel segments that develop angiographically detectable evaginations following BRS implantation through optical coherence tomography (OCT) analysis. In 8 patients, 10 BRS (Absorb, Abbott Vascular, Santa Clara, CA, USA) which displayed coronary evaginations in clinically driven late invasive coronary angiograms were identified and findings were compared to 10 BRS in 8 patients without coronary evaginations. Vessel and device geometry was analyzed in serial OCT cross-sections at a spacing of 200 μm. Measured BRS dimensions were normalized to the reference vessel size at implantation. In OCT, major evaginations on average affected 24 ± 19% of the scaffold length. Scaffolds with major evaginations had a significantly larger lumen area than scaffolds without evaginations (mean normalized lumen area 1.19 ± 0.58 vs. 0.77 ± 0.38; p < 0.001), and also displayed a significantly larger scaffold area (mean normalized scaffold area: 1.36 ± 0.6 vs. 1.13 ± 0.43; p < 0.001), and scaffold diameter (mean normalized scaffold diameter: 1.17 ± 0.33 vs.1.04 ± 0.19; p < 0.001). Lumen area (r = 0.47; p < 0.001), scaffold area (r = 0.52; p < 0.001), and scaffold diameter (r = 0.74; p < 0.001) in the evagination group were positively correlated to the time since scaffold implantation. Coronary evaginations following BRS implantation are associated with an increased scaffold area, indicating that the scaffold follows the outward remodeling of the artery. The process affects the entire scaffold length and seems to be continuously progressing following implantation.

One-year optical coherence tomography findings in patients with late and very-late stent thrombosis treated with intravascular imaging guided percutaneous coronary intervention.

Patients with late/very-late stent thrombosis (ST) are at high risk of recurrent-ST. The mechanisms of recurrent-ST are largely unknown. The objective is to describe the 1-year optical coherence tomography (OCT) findings of patients suffering from late/very-late ST treated with intravascular imaging guided percutaneous coronary intervention (PCI). All consecutive patients with late/very-late ST undergoing intravascular imaging guided PCI were screened to undergo coronary angiography and OCT examination at 1year. Patients were classified according to the observation of stent malapposition as most contributing cause of the ST. Thirty-four patients were included. Stent malapposition was observed in 17 (50%) and the remaining 17 cases were classified as: neoatherosclerosis (n = 9), underexpansion (n = 3) and unknown mechanism (n = 5). Patients with malapposition had a remarkable reduction of the malapposition volume (from 6.4 to 1.3mm3; p = 0.02) during the ST procedure, but this was not fully corrected in 13 (76.5%). At 12 months, two patients of the malapposition group presented with uneventful target vessel re-occlusion. Persistent malapposition was observed in nine patients (60.0%). Major coronary evaginations (46.7 vs. 0%; p = 0.001) and uncovered struts (6.3 vs. 1.0%; p < 0.001) were also more frequent in patients with malapposition than without malapposition. None of the patients had thin-cap fibroatheroma neoatherosclerosis. Contributing causes of late/very-late ST are diverse and have different healing patterns at 12months. Patients with stent malapposition treated with intravascular imaging guided PCI showed poor re-healing; but patients with other causes of the ST showed optimal stent healing as assessed by OCT.

Optical coherence tomography findings: insights from the “randomised multicentre trial investigating angiographic outcomes of hybrid sirolimus-eluting stents with biodegradable polymer compared with everolimus-eluting stents with durable polymer in chronic total occlusions” (PRISON IV) trial

The PRISON IV trial investigated the next-generation sirolimus-eluting stent (SES) with ultra-thin struts and biodegradable polymer against the second-generation everolimus-eluting stent (EES) with thin struts and durable polymer in patients with successfully recanalised chronic total occlusions (CTO). In this study, we examined the secondary optical coherence tomography endpoints. The main PRISON IV trial randomised 330 patients to either SES or EES. At nine months, 281 (85%) patients underwent repeat angiography. Of these, 60 consecutive patients received optical coherence tomography divided over both stent groups. The mean number of struts analysed was 750±337 and 633±358 in SES and EES patients, respectively (p=0.07). The minimal lumen area, minimal stent area, maximal neointima area and neointimal thickness were comparable between the groups (4.8±2.1 and 4.4±1.5 mm2; 5.3±1.8 and 5.3±1.4 mm2; 2.5±2.0 and 2.2±1.5 mm2; 0.7±1.7 and 0.4±0.2 mm). The percentage of uncovered struts was higher with EES (6.2±7.5% and 11.9±13.4%, p=0.04), whereas the percentage of malapposed struts and mean number of coronary evaginations were significantly higher with SES (2.9±4.0% and 1.2±2.4%, p=0.02; 18.5±17.7 and 5.3±3.1, p=0.004). The optical coherence tomography findings of this substudy demonstrated improved strut coverage with ultra-thin strut SES with bioresorbable polymer compared to thin-strut EES with durable polymer in CTO. On the other hand, SES showed a higher rate of stent strut malappositon and coronary evaginations. The clinical relevance of these findings remains to be demonstrated.

1965Major coronary evaginations following implantation of bioresorbable vascular scaffolds: clinical and OCT characteristics

1965Major coronary evaginations following implantation of bioresorbable vascular scaffolds: clinical and OCT characteristics

Mechanisms of stent thrombosis analysed by optical coherence tomography: insights from the national PESTO French registry.

Angiography has limited value for identifying the causes of stent thrombosis (ST). We studied a large cohort of patients by optical coherence tomography (OCT) to explore ST characteristics and mechanisms. A prospective multicentre registry was screened for patients with confirmed ST. Optical coherence tomography was performed after initial intervention to the culprit lesion (in 69% of cases in a deferred procedure). Stent thrombosis was classified as acute (AST), sub-acute (SAST), late (LST), and very late (VLST). Optical coherence tomography records were analysed in a central core lab. The analysis included 120 subjects aged 61.7 [51.4-70.7]; 89% male. Very late ST was the clinical presentation in 75%, LST in 6%, SAST in 15%, and AST in 4% of patients. Bare metal stents (BMS) were used in 39%, drug-eluting stents (DES) in 59% and bioresorbable vascular scaffolds in 2% of the cases. Optical coherence tomography identified an underlying morphological abnormality in 97% of cases, including struts malapposition (34%), neoatherosclerotic lesions (22%), major stent underexpansion (11%), coronary evagination (8%), isolated uncovered struts (8%), edge-related disease progression (8%), and neointimal hyperplasia (4%). Ruptured neoatherosclerotic lesions were more frequent with BMS than with DES (36 vs. 14%, P = 0.005), whereas coronary evaginations were more frequent with DES than with BMS (12 vs. 2%, P = 0.04). LST + VLST were mainly related to malapposition (31%) and neoatherosclerosis (28%), while prominent mechanisms for AST + SAST were malapposition (48%) and underexpansion (26%). In patients with confirmed ST, OCT imaging identified an underlying morphological abnormality in 97% of cases.

Coronary evaginations and peri-scaffold aneurysms following implantation of bioresorbable scaffolds: incidence, outcome, and optical coherence tomography analysis of possible mechanisms.

Peri-stent coronary evaginations may disturb flow and have been proposed as possible risk factor for late stent thrombosis. We describe incidence, predictors, and possible mechanisms of coronary evaginations 12 months after implantation of bioresorbable vascular scaffolds (BVS). One hundred and two BVS implanted in 90 patients (age 63 ± 13 years, 71 males, 14 diabetics) were analysed with angiography and optical coherence tomography (OCT) 12 months after implantation. Evaginations were identified as any hollow in the luminal vessel contour between well-apposed struts and were classified as major when extending ≥3 mm with a depth ≥10% of the BVS diameter. Fifty-five (54%) of the BVS (50(56%) of the patients) had at least one evagination (6.1 ± 6.2 evaginations per BVS), with a mean volume of 1.9 ± 1.9 mm(3). Major evaginations were only found in one patient, and in-BVS aneurysms in three patients (4BVS). The presence of evaginations was strongly associated with that of malapposition (P = 0.003) and strut fractures (P = 0.01). No association could be shown between the presence and volume of the evaginations and any clinical variable or the presence of uncovered struts (P > 0.5). Peri-strut low-intensity areas (PSLIA) were present in 29 (53%) of the BVS with evaginations and 12 (26%) of those without (P = 0.0049); their presence was independently associated with the presence, the number (P < 0.003) and volume of the evaginations (P = 0.004) and with that of strut fracture. Optical coherence tomography-detected evaginations are relatively common after BVS implantation, but, as for modern drug-eluting metallic stents, major evaginations are very rare. Optical coherence tomography evidence of immature neointima and strut fractures were associated with more severe development of evaginations.

Differential healing response attributed to culprit lesions of patients with acute coronary syndromes and stable coronary artery after implantation of drug-eluting stents: An optical coherence tomography study

BackgroundPathology studies have shown delayed arterial healing in culprit lesions of patients with acute coronary syndrome (ACS) compared with stable coronary artery disease (CAD) after placement of drug-eluting stents (DES). It is unknown whether similar differences exist in-vivo during long-term follow-up. Using optical coherence tomography (OCT), we assessed differences in arterial healing between patients with ACS and stable CAD five years after DES implantation. Methods and resultsA total of 88 patients comprised of 53 ACS lesions with 7864 struts and 35 stable lesions with 5298 struts were suitable for final OCT analysis five years after DES implantation. The analytical approach was based on a hierarchical Bayesian random-effects model. OCT endpoints were strut coverage, malapposition, protrusion, evaginations and cluster formation. Uncovered (1.7% vs. 0.7%, adjusted p=0.041) or protruding struts (0.50% vs. 0.13%, adjusted p=0.038) were more frequent among ACS compared with stable CAD lesions. A similar trend was observed for malapposed struts (1.33% vs. 0.45%, adj. p=0.072). Clusters of uncovered or malapposed/protruding struts were present in 34.0% of ACS and 14.1% of stable patients (adj. p=0.041). Coronary evaginations were more frequent in patients with ST-elevation myocardial infarction compared with stable CAD patients (0.16 vs. 0.13 per cross section, p=0.027). ConclusionUncovered, malapposed, and protruding stent struts as well as clusters of delayed healing may be more frequent in culprit lesions of ACS compared with stable CAD patients late after DES implantation. Our observational findings suggest a differential healing response attributable to lesion characteristics of patients with ACS compared with stable CAD in-vivo.

Flow disturbances in stent-related coronary evaginations: a computational fluid-dynamic simulation study

Angiographic ectasias and aneurysms in stented segments have been associated with late stent thrombosis. Using optical coherence tomography (OCT), some stented segments show coronary evaginations reminiscent of ectasias. The purpose of this study was to explore, using computational fluid-dynamic (CFD) simulations, whether OCT-detected coronary evaginations can induce local changes in blood flow. OCT-detected evaginations are defined as outward bulges in the luminal vessel contour between struts, with the depth of the bulge exceeding the actual strut thickness. Evaginations can be characterised cross-sectionally by depth and along the stented segment by total length. Assuming an ellipsoid shape, we modelled 3-D evaginations with different sizes by varying the depth from 0.2-1.0 mm, and the length from 1-9 mm. For the flow simulation we used average flow velocity data from non-diseased coronary arteries. The change in flow with varying evagination sizes was assessed using a particle tracing test where the particle transit time within the segment with evagination was compared with that of a control vessel. The presence of the evagination caused a delayed particle transit time which increased with the evagination size. The change in flow consisted locally of recirculation within the evagination, as well as flow deceleration due to a larger lumen - seen as a deflection of flow towards the evagination. CFD simulation of 3-D evaginations and blood flow suggests that evaginations affect flow locally, with a flow disturbance that increases with increasing evagination size.

Coronary evaginations are associated with positive vessel remodelling and are nearly absent following implantation of newer-generation drug-eluting stents: an optical coherence tomography and intravascular ultrasound study

The purpose of this study was to assess the occurrence, predictors, and mechanisms of optical coherence tomography (OCT)-detected coronary evaginations following drug-eluting stent (DES) implantation. Angiographic ectasias and aneurysms in stented segments have been associated with a risk of late stent thrombosis. Using OCT, some stented segments show coronary evaginations reminiscent of ectasias. Evaginations were defined as outward bulges in the luminal contour between struts. They were considered major evaginations (MEs) when extending ≥3 mm along the vessel length, with a depth ≥10% of the stent diameter. A total of 228 patients who had sirolimus (SES)-, paclitaxel-, biolimus-, everolimus (EES)-, or zotarolimus (ZES)-eluting stents implanted in 254 lesions, were analysed after 1, 2, or 5 years; and serial assessment using OCT and intravascular ultrasound (IVUS) was performed post-intervention and after 1 year in 42 patients. Major evaginations occurred frequently at all time points in SES (∼26%) and were rarely seen in EES (3%) and ZES (2%, P = 0.003). Sirolimus-eluting stent implantation was the strongest independent predictor of ME [adjusted OR (95% CI) 9.1 (1.1-77.4), P = 0.008]. Malapposed and uncovered struts were more common in lesions with vs. without ME (77 vs. 25%, P < 0.001 and 95 vs. 20%, P < 0.001, respectively) as was thrombus [49 vs. 14%, OR 7.3 (95% CI: 1.7-31.2), P = 0.007]. Post-intervention intra-stent dissection and protrusion of the vessel wall into the lumen were associated with an increased risk of evagination at follow-up [OR (95% CI): 2.9 (1.8-4.9), P < 0.001 and 3.3 (1.6-6.9), P = 0.001, respectively]. In paired IVUS analyses, lesions with ME showed a larger increase in the external elastic membrane area (20% area change) compared with lesions without ME (5% area change, P < 0.001). Optical coherence tomography-detected MEs are a specific morphological footprint of early-generation SES and are nearly absent in newer-generation ZES and EES. Evaginations appear to be related to vessel injury at baseline; are associated with positive vessel remodelling; and correlate with uncoverage, malapposition, and thrombus at follow-up.

Long-Term Vascular Healing in Response to Sirolimus- and Paclitaxel-Eluting Stents: An Optical Coherence Tomography Study

This study sought to assess stent strut coverage, malapposition, protrusion, and coronary evaginations as markers of healing 5 years after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES), by optical coherence tomography (OCT). Early-generation drug-eluting stents have been shown to delay vascular healing. A total of 88 event-free patients with 1 randomly selected lesion were suitable for final OCT analysis 5 years after drug-eluting stent implantation. The analytical approach was based on a hierarchical Bayesian random-effects model. OCT analysis was performed at 5 years in 41 SES lesions with 6,380 struts, and in 47 PES lesions with 6,782 struts. A total of 196 struts were uncovered in SES (1.5%) compared with 185 struts in PES lesions (1.0%, 95% credibility interval [CrI]: 0.5 to 1.6; p = 0.32). Malapposed struts were present in 1.2% of SES compared with 0.7% of PES struts (0.7%, 95% CrI: 0.03 to 1.6; p = 0.23). Protruding struts were more frequent among SES (n = 114; 0.8%) than PES lesions (n = 24; 0.1%, 95% CrI: 0.3 to 1.3; p < 0.01). Coronary evaginations were more common among SES- than PES-treated lesions (17 vs. 7 per 100 cross sections, p = 0.003). During extended clinical follow-up, 2 patients suffered from very late stent thrombosis showing a high degree of malapposition, protrusion, and coronary evaginations at the time of OCT investigation. Early-generation drug-eluting stents show a similar degree of strut coverage and malapposition at 5 years of follow-up. Despite an overall low degree of uncovered and malapposed struts in event-free patients, some lesions show a clustering of these characteristics, indicating a heterogeneous healing response, which may be the source for very late adverse events.