Long-term outcomes of minor dissection at the edge of stents detected with intravascular ultrasound

Intravascular imaging in coronary stent restenosis: Prevention, characterization, and management

Despite the introduction of drug-eluting stents to combat the neointimal hyperplasia that occurred after BMS implantation, in-stent restenosis is still encountered in a significant number of patients, particularly as increasingly complex lesions are tackled by percutaneous coronary intervention. Many biological and mechanical factors interplay to produce restenosis, some of which are avoidable. Intravascular imaging provided unique insights into various forms of stent-related mechanical issues that contribute to this phenomenon. From a practical perspective, intravascular imaging can therefore help to optimize the stenting procedure to avert these issues. Moreover, once the problem of restenosis eventuates, imaging can guide the management by tackling the underlying identified mechanism. Finally, it can be used to evaluate the re-intervention results. Nevertheless, with the emergence of different treatment options, more evidence is needed to define patient/lesion-specific characteristics that may help to tailor treatment selection in a way that improves clinical outcomes.

Impact of stent edge dissection detected by optical coherence tomography after current-generation drug-eluting stent implantation

Background

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.

Methods

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).

Results

Of 175 patients, SED detected by OCT was observed in 32 patients, while 143 patients did not show SED. In the crude population, the SED group showed a significantly higher incidence of CD-TLR, definite stent thrombosis, TV-MI and cardiac death relative to the non-SED group. After adjustment by an inverse probability weighted methods, the SED group showed a significantly higher incidence of MACE compared with the non-SED group (hazard ratio 3.43, 95% confidence interval 1.09–10.81, p = 0.035). Fibrocalcific or lipidic plaques, greater lumen eccentricity, and stent-oversizing were the predictors of SED.

Conclusions

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.

Optical coherence tomography assessment of incidence, morphological characteristics, and spontaneous healing course of edge dissections following percutaneous coronary intervention with stent implantation in patients with non-ST segment elevation myocardial infarction

BACKGROUND

Stenting-induced edge dissections (ED) can be assessed in detail by optical coherence tomography (OCT). This study sought to investigate the incidence, morphological characteristics, and spontaneous healing course of OCT-identified EDs following drug-eluting stent (DES) implantation in a non-ST segment elevation myocardial infarction (NSTEMI) patient-population.

METHODS

Acute vessel wall injury at the 5-mm stent adjacent distal and proximal reference segments was assessed by post-procedure OCT and intravascular ultrasound (IVUS) in n=97 NSTEMI-patients (n=97 lesions). Six months OCT follow-up was available in 82 patients (including 35 untreated post-procedure EDs).

RESULTS

The overall incidence of post-procedure OCT-detected ED was 38 per 97 patients (39.2%), and 47 per 182 stent edges (25.8%). None of the EDs were angiographically visualizable, while 10 (21.3%) were visible on concomitant IVUS-analysis. Morphologically, there was a significant difference in plaque type present at ED-edges vs. non-ED-edges when assessed with OCT; (1) lipid-rich and calcified plaques: 80.9% vs. 57.0%, (2) fibrous plaques: 17.0% vs. 26.7%, and (3) normal coronary vessels: 2.1% vs. 16.3%, p<0.01. Plaqueburden, assessed by IVUS, was substantially larger at ED-containing borders: 54.5±10.0% vs. 43.7±11.6%, p=0.01. Three dissections (8.6%) were incompletely healed at 6-month OCT follow-up. None of the EDs caused cardiac events during the 6-month follow-up, however, 1 ED-patient had target lesion revascularization with PCI and DES-implantation in extension of the scheduled OCT-control.

CONCLUSIONS

OCT-detected EDs were frequent after stent implantation due to NSTEMI, and the majority of these EDs healed without leading to an adverse prognosis at 6months.

The effect of statin treatment on the prevention of stent mediated flow limited edge dissections during PCI in patients with stable angina

OBJECTIVES

The effect of statin therapy before PCI with direct stenting may reduce the development of flow limited edge dissections (ED) in patients with stable angina.

BACKGROUND

Flow limited ED after PCI is associated with an increased risk of major adverse cardiovascular events. Statin therapy induces important changes in the plaque composition which have been previously identified as strong predictors of ED.

MATERIAL AND METHODS

100 patients complicated with flow limited ED and 100 control patients with successful procedure were enrolled into the study. EDs were described as the 5-mm regions that were immediately adjacent to the stent borders, both distally and proximally on the coronary angiography.

RESULTS

Rate of statin use and duration of statin use were significantly higher in patients with non-ED group (63%) versus ED group (25%) (p<0.001). In addition, patients in ED group had significantly higher levels of C-reactive protein (CRP) at admission (9.9mg/dL (5.89-16.45) vs. 4.40mg/dL (3.5-7.09), respectively, p=0.014).

CONCLUSIONS

Our findings suggested that maintenance statin treatment before PCI with direct stenting may reduce the development of flow limited ED in patients with stable angina.

Prevalence, Features, and Prognostic Importance of Edge Dissection After Drug-Eluting Stent Implantation

Background—

Intravascular ultrasound detects stent edge dissections after percutaneous coronary intervention that are not seen angiographically. This study investigated the association between stent edge dissections and clinical outcomes.

Methods and Results—

ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a large-scale, prospective, multicenter study of patients undergoing drug-eluting stent implantation. In this prospective substudy, 2062 patients (2433 lesions) were evaluated with intravascular ultrasound to characterize the morphological features and clinical outcomes of stent edge dissection after percutaneous coronary intervention. The prevalence of post–percutaneous coronary intervention stent edge dissection was 6.6% per lesion (161 of 2433). Calcified plaque at the proximal stent edge (relative risk [RR]=1.72; P =0.04) and proximal stent edge expansion (RR=1.18; P =0.004) were predictors for proximal dissection; attenuated plaque at the distal stent edge (RR=3.52; P =0.004), distal reference plaque burden (RR=1.56; P <0.0001), and distal edge stent expansion (RR=1.11; P =0.02) were predictors for distal dissection. At 1-year follow-up, target lesion revascularization was more common in lesions with versus without dissection (5.2% versus 2.7%; P =0.04). Multivariable analysis indicated that residual dissection was associated with target lesion revascularization at 1-year follow-up (RR=2.67; P =0.02). Among lesions with dissection, smaller effective lumen area increased the risk of target lesion revascularization at 1-year follow-up (cutoff value of 5.1 mm 2 ; P =0.05).

Conclusions—

Greater stent expansion and the presence of large, calcified, and/or attenuated plaques were independent predictors of stent edge dissection. Residual stent edge dissection, especially with a smaller effective lumen area, was associated with target lesion revascularization during 1-year follow-up after drug-eluting stent implantation.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00638794.

Intravascular Ultrasound for the Assessment of Coronary Lesion Severity and Optimization of Percutaneous Coronary Interventions

Intravascular ultrasound (IVUS) has provided valuable information on cross-sectional coronary vascular structure and has played a key role in contemporary stent-based percutaneous coronary interventions (PCI). It accurately assesses coronary anatomy, assists in the selection of treatment strategy, and helps to optimize stenting outcomes. IVUS-guided PCI for drug-eluting stent implantation seems to be associated with a significantly reduced risk of death, myocardial infarction, target lesion revascularization, and stent thrombosis.

A comparison of tissue prolapse with optical coherence tomography and intravascular ultrasound after drug-eluting stent implantation

The aim of this study was to compare the detection rate of tissue prolapse (TP) in optical coherence tomography (OCT) and intravascular ultrasound (IVUS) after drug-eluting stent (DES) implantation and evaluate clinical implication of TP at 2 years after percutaneous coronary intervention. In spite of the superiority of OCT in the aspect of resolution when it was compared to IVUS, there was little data about the superiority of OCT in detecting TP. And there has been controversy about the clinical significance of TP. We enrolled 38 patients who treated with DES implantation. OCT and IVUS measurements were performed in stented segments immediately after percutaneous coronary intervention. We matched OCT and IVUS images one by one, and analyzed TP quantitatively in both measurements. Thirty patients (78.9 %) were followed-up for 2 years to evaluate clinical outcome of TP. TP was detected in 95 % of stented lesions by OCT and 45 % of stented lesions by IVUS among 40 stented lesions in 38 patients. The best cut-off values of the area, depth and burden of TP on OCT for the detection of TP on IVUS were 0.17 mm(2), 0.17 mm and 1.98 %, respectively. There was no statistically significant relation between TP and major adverse cardiac event during hospitalization and 2-year follow-up.

Healing course of acute vessel wall injury after drug-eluting stent implantation assessed by optical coherence tomography

BACKGROUND

Vessel wall injury after drug-eluting stent (DES) implantation can be characterized in detail by optical coherence tomography (OCT). Little is known about the healing course of these phenomena.

METHODS AND RESULTS

In 62 lesions (62 patients), the incidence of acute vessel trauma was assessed in the stented region and the edge segments immediately after DES implantation. The healing course of these injuries was assessed at 9-month OCT follow-up using a software algorithm allowing for reliable spatial comparison of baseline and follow-up cross-sectional images. Tissue prolapse (TP) and tissue protrusions were detected in 81 and 35% of lesions, respectively. A total of 342 intra-stent dissection flaps (ISD) and 114 intra-stent dissection cavities (ISC) were visualized in 98 and 81% of lesions, respectively. Thirty-five lesions (56%) showed edge dissections (EDs). No residual TP or protrusion was observed at follow-up. Incomplete healing was seen in 8% of ISD and in 20% of ISC. For ED, a residual flap was observed in one-third of the initially dissected stent edges. Incomplete healing of acute vessel injury was associated with the presence of underlying atherosclerotic disease at baseline. Uncovered and malapposed stent struts were observed more often with incomplete healing of vessel injury at follow-up.

CONCLUSIONS

Acute vessel wall trauma is highly prevalent immediately after DES implantation. Most of these injuries are minor and resolve at mid-term follow-up. Incomplete healing of ISDs seems to be associated with other OCT findings suggesting delayed arterial healing.

Multi-modality imaging for stent edge assessment

Optical coherence tomography (OCT) has a sufficiently high resolution to allow assessment of stent edge dissection (ED). The aims of the present study were as follows: (1) evaluation of the frequency of stent ED using OCT; (2) comparison of stent ED detection rates obtained using angiography, intravascular ultrasound (IVUS), and OCT; and (3) IVUS-Virtual Histology (IVUS-VH) evaluation of plaque composition at the site of stent EDs detected by OCT after percutaneous coronary intervention (PCI). Fifty-eight consecutive patients (59 lesions, 100 stent edges) who underwent balloon-expandable stent implantation and post-stent assessment with OCT and IVUS-VH were included. OCT revealed stent ED in 24.0 % (24 of 100) of stent edges after PCI with a balloon-expandable stent. In contrast, ED was detected in only 3.0 % (3 of 100) of stent edges using angiography and 4.0 % (4 of 100) of stent edges using IVUS. Plaque evaluation using IVUS-VH showed that the percent necrotic core (21.2 ± 8.3 vs. 13.4 ± 10.7 %, p = 0.001) and absolute dense calcium (2.9 ± 2.4 vs. 1.3 ± 2.2 mm(3), p = 0.0104) and dense calcium (13.8 ± 9.3 vs. 5.4 ± 5.8 %, p < 0.001) volumes were greater in the ED group than in the non-ED group. Thus, OCT is superior to conventional coronary angiography and IVUS in the identification of stent ED. In addition, the plaque composition at the ED site is characterized by a necrotic core and greater dense calcium levels than those observed at the non-ED site.

Frequency-domain optical coherence tomography findings in patients with bifurcated lesions undergoing provisional stenting

AIMS

Bifurcations represent challenging lesions which may benefit from improved understanding of stent-related vessel complications. Since optical coherence tomography (OCT) allows us to detect post-stenting vessel injuries, we sought to assess the geographic pattern of stent-related complications occurring during provisional stenting of bifurcated lesions.

METHODS AND RESULTS

Fifty-one patients with bifurcated lesions treated by provisional stenting and undergoing intra-procedural OCT assessment were enrolled. OCT images were acquired with the aim of guiding the percutaneous coronary intervention but were re-analysed off-line for the present study. The stented bifurcation was divided into four segments [three in the main vessel (MV) and one in the side branch (SB)]. The following acute post-stenting vessel injuries/complications at the different bifurcation segments were evaluated: (i) stent under-expansion, (ii) stent malapposition, (iii) stent edge dissection, (iv) side-branch ostium dissection, (v) tissue prolapse, (vi) intracoronary thrombus, and (vii) in-stent dissection. A total of 55 bifurcation lesions undergoing provisional stenting were analysed. At least one OCT complication was detectable in all cases. Across different bifurcation sites, significant differences in the occurrence of stent complications were observed. In particular, stent malapposition was more common at the proximal MV segment (P < 0.001), while tissue prolapse was more common at the distal MV segment (P < 0.001).

CONCLUSION

In bifurcated interventions, OCT often detects vessel injuries/stent complications, which tend to have a specific geographical distribution. In particular, stent malapposition is more common at the proximal MV and tissue prolapse at the distal MV segment.

Intravascular ultrasound predictors for edge restenosis after newer generation drug-eluting stent implantation

The aim of the present study was to assess the intravascular ultrasound predictors for angiographic edge restenosis after newer generation drug-eluting stent implantation. A total of 820 patients (987 lesions) who underwent newer generation drug-eluting stent placement (236 Endeavor zotarolimus-eluting stents, 246 Resolute zotarolimus-eluting stents, and 505 everolimus-eluting stents) with 9 months of angiographic surveillance were enrolled. The post-stenting angiographic and intravascular ultrasound images of 1,668 reference segments (681 proximal and 987 distal) were analyzed. Overall, 37% of angiographically normal proximal reference segments and 21% of angiographically normal distal reference segments had plaque burden >50%. In the overall cohort of 1,668 reference segments, 47 (2.8%) had 9-month angiographic edge restenosis (diameter stenosis >50%). Edge restenosis was predicted by a post-stenting reference segment plaque burden >54.5% (sensitivity 81%, specificity 80%) and a reference segment minimum lumen area of 5.7 mm(2) (sensitivity 72%, specificity 59%). The edge restenosis rate was 2.1% in the Endeavor zotarolimus-eluting stents, 2.4% in the Resolute zotarolimus-eluting stents, and 3.4% in the everolimus-eluting stents lesions (p = 0.311). The predictive cutoff of the reference plaque burden was 56.3% for Endeavor zotarolimus-eluting stents, 57.3% for Resolute zotarolimus-eluting stents, and 54.2% for everolimus-eluting stents. The criteria for residual plaque burden were similar between proximal and distal reference segments (56.4% vs 51.9%, respectively), but the minimum lumen area criteria were quite different (<7.1 mm(2) for proximal vs <4.8 mm(2) for distal reference segments). In conclusion, after newer drug-eluting stent implantation, edge restenosis was predicted by post-stenting reference segment plaque burden >55%.

Predictors and incidence of stent edge dissections in patients with type 2 diabetes as determined by optical coherence tomography

Patients with type 2 diabetes are at increased risk for post-PCI complications including stent thrombosis and restenosis. Stent edge dissections (SEDs) have been associated with these complications. This study assessed incidence and predictors of SEDs in patients with type 2 diabetes using optical coherence tomography (OCT). Intravascular lesion parameters and plaque morphology were investigated pre- and post-PCI using OCT in 73 type 2 diabetic patients with 90 lesions and 166 visible stent edges. We detected 42 (25.3 %) SEDs in 166 stent edges and 37 (41.1 %) SEDs in 90 lesions. More SEDs occurred if the border of the stent had been placed within diseased vessel segments with predominantly fibrous (42.9 %) and fibrocalcific (40.5 %) plaques compared to healthy vessel wall morphology (p < 0.001). Furthermore, the lumen eccentricity of the stent at its edges (SAE) (16.00 ± 6.07 vs. 13.11 ± 5.22 %, p < 0.003) and the stent-edge-to-lumen-area-ratio (1.26 ± 0.27 vs. 0.99 ± 0.20, p < 0.001) were both significantly larger in the presence of SEDs. All of the above parameters were significant predictors for SEDs on uni- and multivariate logistic regression analysis (all p < 0.01), suggesting that the lumen eccentricity of the SAE, the stent-edge-to-lumen-area-ratio and diseased vessel wall morphology of the reference segment adjacent to the stent edge are independent risk factors for the presence of SEDs. These results suggest that diseased vessel wall morphology at the stent edges may promote the occurrence of SEDs and that avoidance of longitudinal and transverse mismatch between stent and vessel could be important to reduce SEDs in cardiovascular high-risk patients with type 2 diabetes.

Natural consequence of post-intervention stent malapposition, thrombus, tissue prolapse, and dissection assessed by optical coherence tomography at mid-term follow-up

Aims

We performed this study to clarify natural consequences of abnormal structures (stent malapposition, thrombus, tissue prolapse, and stent edge dissection) after percutaneous coronary intervention (PCI).

Methods and results

Thirty-five patients treated with 40 drug-eluting stents underwent serial optical coherence tomography (OCT) imaging immediately after PCI and at the 8-month follow-up. Among a total of 73 929 struts in every frame, 431 struts (26 stents) showed malapposition immediately after PCI. Among these, 49 remained malapposed at the follow-up examination. The mean distance between the strut and vessel wall (S–V distance) of persistent malapposed struts on post-stenting OCT images was significantly longer than that of resolved malapposed struts (342 ± 99 vs. 210 ± 49 μm; P <0.01). Based on receiver-operating characteristic curve analysis, an S–V distance ≤260 µm on post-stenting OCT images was the corresponding cut-off point for resolved malapposed struts (sensitivity: 89.3%, specificity: 83.7%, area under the curve = 0.884). Additionally, 108 newly appearing malapposed struts were observed on follow-up OCT, probably due to thrombus dissolution or plaque regression. Thrombus was observed in 15 stents post-PCI. Serial OCT analysis revealed persistent thrombus in 1 stent, resolved thrombus in 14 stents, and late-acquired thrombus in 8 stents. Tissue prolapse observed in 38 stents had disappeared at the follow-up. All eight stent edge dissections were repaired at the follow-up.

Conclusion

Most cases of stent malapposition with a short S–V distance, thrombus, tissue prolapse, or minor stent edge dissection improved during the follow-up. These OCT-detected minor abnormalities may not require additional treatment.

Intravascular ultrasound-guided systematic two-stent techniques for coronary bifurcation lesions and reduced late stent thrombosis

BACKGROUND

The effects of intravascular ultrasound (IVUS)-guided complex approaches using drug-eluting stents (DES) for coronary bifurcation lesions on clinical outcomes has not yet been studied in detail.

OBJECTIVE

Our objective was to analyze the difference in 1-year outcomes following two-stent techniques involving implantation of DES for coronary bifurcation lesions between IVUS-guided and angiography-guided groups.

METHODS

From May 26, 2007 to March 24, 2010, 628 patients received two-stent techniques (324 in the IVUS-guided group and 304 angiography-guided) and were prospectively studied. We compared major adverse cardiac events (MACE, including cardiac death, stent thrombosis [ST], myocardial infarction [MI] and target lesion/vessel revascularization) at 12-months follow-up, before and after adjusting for propensity score matching.

RESULTS

At 12-months after the indexed procedure, patients in the angiography-guided group had significantly increased in-stent restenosis. Compared to the angiography-guided group, the IVUS-guided group had a significantly lower overall unadjusted ST rate (1.2% vs. 6.9%, P < 0.001), definite ST (0.6% vs. 5.3%, P < 0.001), late ST (0.6% vs. 4.3%, P = 0.003), MI (4.6% vs. 8.9%, P = 0.038) and cardiac death (0.9% vs. 3.3%, P = 0.049). By propensity score matching, 123 paired patients were matched. The late ST at 12-months follow-up was 0% in the IVUS-guided group versus 4.9% in the angiography-guided group (P = 0.029), resulting in significant differences in ST-elevation MI between the two groups (2.4% vs. 9.8%, P = 0.030).

CONCLUSIONS

The IVUS-guided two-stent technique was associated with significantly reduced late stent thrombosis, with a resultant reduction in ST-elevation MI. © 2012 Wiley Periodicals, Inc.

Optimization of stent deployment by intravascular ultrasound

Intravascular ultrasound (IVUS) is a useful diagnostic method that provides valuable information in addition to angiography regarding the coronary vessel lumen, dimensions, plaque burden, and characteristics. The major use of IVUS in coronary intervention is to guide interventional strategies and assess optimal stent deployment. Since the introduction of the drug-eluting stent (DES), concerns about restenosis have decreased. However, high-risk lesion subsets are being routinely treated with DESs, and the incidence of suboptimal results after stent deployment, such as stent underexpansion, incomplete stent apposition, edge dissection, geographic miss, and the risk of stent thrombosis, have correspondingly increased. Thus, optimization of stent deployment under IVUS guidance may be clinically important. In this review, we focus on the potential role of IVUS in stent optimization during percutaneous coronary intervention and its clinical benefits.

Natural history of stent edge dissection, tissue protrusion and incomplete stent apposition detectable only on optical coherence tomography after stent implantation – preliminary observation –

BACKGROUND

The clinical impact of stent edge dissection, tissue protrusion, and incomplete stent apposition (ISA) after stent implantation, detectable only on optical coherence tomography (OCT), is still unknown because the natural course has not been investigated.

METHODS AND RESULTS

All consecutive patients with angina pectoris in whom both intravascular ultrasound (IVUS) and OCT were performed immediately after stenting and at follow-up were included in the present study. The natural history of OCT-detected stent edge dissection, tissue protrusion, and ISA during follow-up was investigated. A total of 36 patients with 39 lesions was analyzed. At baseline, OCT showed 12 stent edge dissections, 25 tissue protrusions, and 8 ISAs, whereas IVUS demonstrated 6 stent edge dissections, 5 tissue protrusions, and 3 ISAs. All IVUS findings were clearly visualized on OCT. The maximum length of dissection flap and depth of ISA visualized on OCT were significantly shorter than those visualized on IVUS. Maximum length of tissue protrusion tended to be smaller on OCT than on IVUS. At follow-up (median 188 days), all findings noted on OCT were healed or resolved without any restenosis or thrombus formation.

CONCLUSIONS

Acute findings after stenting, such as edge dissection, tissue protrusion, and ISA, detectable only on OCT, tended to be smaller than those seen on both OCT and IVUS. The majority of OCT-detected acute findings resolved completely at follow-up.

Relation between plaque type and dissections at the edges after stent implantation: an optical coherence tomography study

BACKGROUND

Stent implantation can create vessel damage such as edge dissections. The objectives were i) to evaluate the frequency of edge dissections after stenting visible by intracoronary optical coherence tomography (OCT) in comparison with angiography. ii) to assess with OCT the plaque type left at the stent edges after implantation, and iii) to study whether there is an association between plaque type and dissections at stent edges.

METHODS

Seventy-three consecutive patients (80 vessels) with OCT post-stent implantation were included in the study. By OCT, plaque type at stent edges and presence of edge dissection were assessed. Angiograms were analyzed by two independent observers to assess the presence of edge dissections.

RESULTS

Distal and proximal edges were visible by OCT in 72/80 and 45/80 vessels respectively. OCT and angiography agreed in the detection of 7 dissections at distal edge (κ=0.32) and 1 dissection at proximal edge (κ=0.22). Plaque type at distal edge was: fibrotic 55.6%, fibrocalcific 22.2%, fibroatheroma 15.3% and thin-cap fibroatheroma (TCFA) 6.9%. At proximal edge plaque type was: fibrotic 31.1%, fibrocalcific 33.3%, fibroatheroma 28.9% and TCFA 6.7%. In the distal edge, presence of edge dissection was significantly more frequent when the plaque type at the edge was fibrocalcific (43.8%) or lipid rich (37.5%) than when the plaque was fibrous (10%) p=0.009.

CONCLUSIONS

OCT showed higher sensitivity compared to angiography for the identification of edge dissections. A high proportion of patients showed lipid-rich plaques at stent edges. Plaque type at the stent edges has impact on the presence of edge dissections.

Intravascular ultrasonography-guided stent angioplasty of an extracranial vertebral artery dissection

The authors report on a case of intravascular ultrasonography (IVUS)-guided stent angioplasty for iatrogenic extracranial vertebral artery (VA) dissection in a 49-year-old man after coil embolization for an unruptured aneurysm of the right posterior inferior cerebellar artery. Insignificant dissections occurred during the procedure. Postoperatively, the patient experienced gradually worsening posterior neck pain and headache, and follow-up angiography 8 months after the coil embolization revealed expansion of the dissection. The patient underwent stent angioplasty with IVUS guidance and his symptoms improved.

To the authors' knowledge, this is the first report of IVUS-guided stent angioplasty of an extracranial VA dissection. It was safe and feasible to treat extracranial VA dissections with stent placement under IVUS guidance. Intravascular environments are in real time with IVUS, and this technique is useful in the confirmation of a true lumen and evaluation of appropriate stent apposition. More clinical experience with this technique is necessary and mandatory, and devices with smaller diameters with improved trackability are essential for further introduction of IVUS into the field of endovascular neurosurgery.

Late in-stent coronary dissection in an elderly woman: An interesting case report

Primary or de novo spontaneous coronary dissection has been reported in many cases; however, in-stent dissection was demonstrated in the previously stented segment of coronary artery only in an autopsy study. Therefore, we report a 78-year-old female presenting with angina pectoris and dyspnea for the last 20 days. She had undergone stent implantation for a significant stenosis in the left anterior descending artery 3 years ago. In-stent dissection flap limiting coronary flow was noted at the coronary angiography and successfully treated with coronary re-stenting. She had no symptoms at follow-up.

Incidence, predictors, and outcomes of coronary dissections left untreated after drug-eluting stent implantation†

AIMS

Coronary dissections left untreated after percutaneous coronary intervention are associated with unfavourable outcomes. However, their role after drug-eluting stent (DES) implantation is still undescribed. We assessed incidence, predictors, and outcomes of residual dissections in DES-treated lesions.

METHODS AND RESULTS

Consecutive patients undergoing DES implantation were enrolled in four Italian centres, with baseline, procedural, and outcome data entered into a dedicated database. Residual dissections were classified according to the National Heart Lung and Blood Institute criteria. End-points of interest were in-hospital, 1-month, and 6-month major adverse cardiovascular events (MACE, i.e. death, myocardial infarction, or target vessel revascularization), and stent thrombosis (ST). Among the 2418 included patients (4630 lesions), a total of 77 (1.7%) final dissections occurred in 67 (2.8%) subjects. Dissections were more frequent in longer and complex lesions and in the left anterior descending, and were associated with increased rates of in-hospital (11.9 vs. 5.2%, P=0.017) and 1-month MACE (13.4 vs. 6.0%, P=0.013), with similar 6-month trends. Cumulative ST was also greater in patients with dissections (6.3 vs. 1.3%, P=0.011). Even non-obstructive dissections with thrombolysis in myocardial infarction 3 flow conferred a significantly worse prognosis.

CONCLUSION

This study, reporting for the first time on incidence, predictors, and outcomes of residual dissections in DES-treated coronary lesions, demonstrates their adverse clinical impact and supports the pursuit of a strategy of sealing dissection flaps with other DES.

Findings of intravascular ultrasound during acute stent thrombosis

OBJECTIVE

To evaluate the potential role of intravascular ultrasound (IVUS) in evaluating patients experiencing an episode of acute stent thrombosis.

DESIGN AND SETTING

Prospective observational study in a cardiac catheterisation laboratory in a university teaching hospital.

PATIENTS AND INTERVENTIONS

IVUS was used to examine 12 patients undergoing coronary interventions for stent thrombosis to gain further mechanistic insights and to guide treatment. IVUS studies were obtained before and after intervention with a motorised pullback device.

MAIN OUTCOME MEASURES

Qualitative and volumetric IVUS analyses.

RESULTS

Angiographically, 10 patients had occluded vessels and two patients had intraluminal filling defects within the stent. IVUS showed an occlusive thrombus in all patients. Thrombus volume was 90 (77) mm3, which was 51 (21)% of total stent volume. There was evidence of severe stent underexpansion in most patients and no patient fulfilled standard criteria for optimal stent implantation. Stent malapposition was detected in four patients, edge dissections were seen in two patients, and significant inflow-outflow disease was present in 11 patients. During interventions IVUS findings led to the use of higher pressures or larger balloons than those used during initial stenting in 10 patients. In addition, four patients required additional stenting, whereas a thrombectomy device alone was selected for one patient. After the procedure final minimum stent area (7.1 (2.1) v 5.3 (2) mm2, p < 0.005) and stent expansion (83.2 (17) v 62.1 (15)%, p < 0.005) improved compared with pre-interventional values. However, residual lining thrombus was still visualised in eight patients (25 (19) mm3, accounting for a 17% of final stent volume).

CONCLUSIONS

IVUS provides an attractive technique to characterise fully the pattern of stent thrombosis, to identify readily the underlying mechanical predisposing factors, and to guide repeated coronary interventions.

Assessment of contemporary stent deployment using intravascular ultrasound

Four second- and third-generation coronary stents were evaluated using QCA and intravascular ultrasound for adequacy of stent expansion, the influence of disease burden on adequacy of deployment, and postdeployment structural effects on the artery. Despite satisfactory stent deployment rates on angiography of 92 %, adequate stent deployment by IVUS ranged from 38% to 55%. There was no significant difference in deployment success across the four stent types. Lesions with significant plaque burden were associated with a lower rate of deployment success (P = 0.04). Twenty-one edge dissections were demonstrated by IVUS; only six were detected by angiography. Observations made on first-generation stents regarding adequacy of deployment still hold true for newer-generation stents. Significant plaque burden is an independent negative predictor of stent deployment success. The presence of IVUS-detected edge dissections indicates that the extent of injury during PCI extends beyond the physical length of the stent.