Impact of stent deployment procedural factors on long-term effectiveness and safety of sirolimus-eluting stents (final results of the multicenter prospective STLLR trial)

IVUS-Guided Versus OCT-Guided Coronary Stent Implantation: A Critical Appraisal

Procedural guidance with intravascular ultrasound (IVUS) imaging improves the clinical outcomes of patients undergoing percutaneous coronary intervention (PCI) by: 1) informing the necessity for lesion preparation; 2) directing appropriate stent sizing to maximize the final stent area and minimize geographic miss; 3) selecting the optimal stent length to cover residual disease adjacent to the lesion, thus minimizing geographic miss; 4) guiding optimal stent expansion; 5) identifying acute complications (edge dissection, stent malapposition, tissue protrusion); and 6) clarifying the mechanism of late stent failure (stent thrombosis, neointimal hyperplasia, stent underexpansion or fracture, or neoatherosclerosis). Optical coherence tomography (OCT) provides similar information to IVUS (with some important differences), also potentially improving acute and long-term patient outcomes compared to angiography-guided PCI. The purpose of this review is to describe the similarities and differences between IVUS and OCT technologies, and to highlight the evidence supporting their utility to improve PCI outcomes.

Algorithmic Approach for Optical Coherence Tomography-Guided Stent Implantation During Percutaneous Coronary Intervention

Intravascular imaging plays a key role in optimizing outcomes for percutaneous coronary intervention (PCI). Optical coherence tomography (OCT) utilizes a user-friendly interface and provides high-resolution images. OCT can be used as part of daily practice in all stages of a coronary intervention: baseline lesion assessment, stent selection, and stent optimization. Incorporating a standardized, algorithmic approach when using OCT allows for precision PCI.

Comparison of short-term clinical outcomes between Resolute Onyx zotarolimus-eluting stents and everolimus-eluting stent in patients with acute myocardial infarction: Results from the Korea Acute Myocardial infarction Registry (KAMIR)

BACKGROUND

There are few studies which compare the efficacy and safety of the Resolute Onyx zotarolimus-eluting stent (O-ZES) and everolimus-eluting stent (EES) in patients with acute myocardial infarction (AMI). Therefore, the present study aimed to compare clinical outcomes of O-ZES and EES in patients with AMI undergoing successful percutaneous coronary intervention (PCI).

METHODS

From January 2016 to December 2016, the Korea Acute Myocardial Infarction Registry (KAMIR) enrolled 3,364 consecutive patients. Among them, O-ZES was used in 402 patients and EES was used in 1,084 patients. The primary endpoint was target lesion failure (TLF), as defined by composite of cardiac death, target vessel myocardial infarction (TV-MI), and ischemic driven-target lesion revascularization (ID-TLR) at 6 month clinical follow-up.

RESULTS

At 6 months, the incidence of TLF was not significantly different between O-ZES and EES group (4.0% vs. 3.9%, adjusted hazard ratio [HR] 1.17, 95% confidential interval [CI] 0.58-2.35, p = 0.665). O-ZES also showed similar results of cardiac death (3.7% vs. 3.4%, adjusted HR 1.25, 95% CI 0.59-2.63, p = 0.560), TV-MI (0.2% vs. 0.6%, adjusted HR 0.56, 95% CI 0.07-4.85, p = 0.600), ID-TLR (0.0% vs. 0.3%, p = 0.524), and definite or probable stent thrombosis (0.2% vs. 0.3%, adjusted HR 0.63, 95% CI 0.06-6.41, p = 0.696) when compared with EES.

CONCLUSIONS

The present study shows that implantation of O-ZES or EES provided similar clinical outcomes with similar risk at 6-month of TLF and definite/probable ST in patients with AMI undergoing successful PCI.

Robotic-Assisted Percutaneous Coronary Intervention: Rationale, Implementation, Case Selection and Limitations of Current Technology

Interventional cardiologists have witnessed an explosive growth in the field. A wide array of percutaneous procedures allow us to treat numerous cardiac conditions less invasively. However, the way we work has changed very little over the past decades. We continue to stand at the tableside for prolonged periods of time, exposing ourselves to the very real risks of radiation exposure as well as to the associated orthopedic injuries from radiation protection. The precision of our procedures is limited by the distance from the fluoroscopic images and, furthermore, patients are potentially at risk from operator fatigue caused by a physician standing at the table for prolonged periods while wearing cumbersome radiation protection gear. Robotic-assisted coronary intervention removes the operator from the radiation field and has been shown to markedly reduce operator exposure as well as allow for more precise positioning of balloons and stents. This technology holds great promise for making interventional procedures safer and more comfortable for the operators as well as reducing fatigue, potentially improving patient outcomes. Currently, we are in an ‘early adopter’ phase of this technology and this paper reviews the rationale, methodology, optimal case selection, and limitations of robotic-assisted coronary intervention.

Robotics in percutaneous cardiovascular interventions

INTRODUCTION

The fundamental technique of performing percutaneous cardiovascular (CV) interventions has remained unchanged and requires operators to wear heavy lead aprons to minimize exposure to ionizing radiation. Robotic technology is now being utilized in interventional cardiology partially as a direct result of the increasing appreciation of the long-term occupational hazards of the field. This review was undertaken to report the clinical outcomes of percutaneous robotic coronary and peripheral vascular interventions. Areas covered: A systematic literature review of percutaneous robotic CV interventions was undertaken. The safety and feasibility of percutaneous robotically-assisted CV interventions has been validated in simple to complex coronary disease, and iliofemoral disease. Studies have shown that robotically-assisted PCI significantly reduces operator exposure to harmful ionizing radiation without compromising procedural success or clinical efficacy. In addition to the operator benefits, robotically-assisted intervention has the potential for patient advantages by allowing more accurate lesion length measurement, precise stent placement and lower patient radiation exposure. However, further investigation is required to fully elucidate these potential benefits. Expert commentary: Incremental improvement in robotic technology and telecommunications would enable treatment of an even broader patient population, and potentially provide remote robotic PCI.

Diagnosis and management challenges of in-stent restenosis in coronary arteries

Over the course of the 3 decades, percutaneous coronary intervention (PCI) with stent implantation transformed the practice of cardiology. PCI with stenting is currently the most widely performed procedure for the treatment of symptomatic coronary disease. In large trials, drug-eluting stents (DES) have led to a significant reduction in in-stent restenosis (ISR) rates, one of the major limitations of bare-metal stents. Due to these favorable findings, DES was rapidly and widely adopted enabling more complex coronary interventions. Nevertheless, ISR remains a serious concern as late stent complications. ISR mainly results from aggressive neointimal proliferation and neoatherosclerosis. DES-ISR treatment continues to be challenging complications for interventional cardiologists.

Does calcium burden impact culprit lesion morphology and clinical results? An ADAPT-DES IVUS substudy

BACKGROUND

Increasing coronary lesion calcification is thought to be associated with adverse percutaneous coronary intervention (PCI) and clinical outcomes. We investigated the effects of calcium burden on culprit lesion morphology and clinical events after intravascular ultrasound (IVUS)-guided PCI in the ADAPT-DES study.

METHODS

ADAPT-DES was a prospective, multicenter registry of 8582 consecutive patients undergoing successful PCI using DES. A pre-specified virtual histology (VH)-IVUS substudy of 638 culprit lesions (638 patients) had both pre- and post-PCI VH-IVUS. We divided lesions into tertiles according to pre-PCI percent dense calcium volume (DCV%=dense calcium/plaque volume×100).

RESULTS

Compared with low and intermediate DCV% tertiles, patients in the high DCV% tertile had the largest arc of superficial calcium, highest percentage of necrotic core volume, and smallest remodeling index; they were also more likely to have advanced lesion morphology such as attenuated plaque and VH thin-cap fibroatheromas. In the high DCV% tertile IVUS guidance was associated with a minimum stent area that was smaller than tertiles with less calcium (p=0.01), but acceptable range, and similar stent expansion (73.8±16.8% vs. 74.0±19.2% vs. 72.4±17.3%, p=0.62) after more frequent use of rotational atherectomy and higher maximum inflation pressure. There was no significant association between pre-PCI DCV% and 2-year target lesion revascularization or major adverse cardiac events (cardiac death, myocardial infarction, or stent thrombosis).

CONCLUSIONS

Increasing coronary artery calcification burden was associated with more advanced, complex VH-IVUS lesion morphology, but not with adverse clinical outcomes, perhaps due to more aggressive PCI techniques that optimized stent expansion.

Does direct stenting with drug-eluting stents improve outcome? A meta-analysis of 10,900 patients

OBJECTIVES

The aim of this study is to summarize the outcomes of patients undergoing direct stenting (DS) with drug-eluting stents (DES) compared to those who underwent balloon predilatation.

BACKGROUND

DS has been associated with improved outcomes in the bare-metal stent era. Although DS with DES implantation has been increasingly adopted in clinical practice, its safety and effectiveness remain controversial.

METHODS

The search criteria identified 546 studies in the Medline/PubMed, Cochrane, and EMBASE databases from 2001 to July 2014. From these, seven studies totaling 10,900 patients were selected. Summarized estimates [odds ratio (OR) and 95% confidence intervals] were obtained using a random-effects model. The primary outcomes were a composite of major adverse cardiac events (MACE), including all-cause death, myocardial infarction (MI), and repeat revascularization. The secondary outcomes included a composite of death and MI and the rates of target lesion revascularization (TLR).

RESULTS

Overall, 4101 (38%) and 6799 (62%) patients underwent DS with DES and balloon pre-dilatation, respectively. DS with DES reduced the likelihood of MACE (OR: 0.81 [0.71-0.93]). Additionally, DS with DES was associated with reduced rates of death/MI (OR: 0.76 [0.62-0.92]), and TLR (OR: 0.66 [0.44-0.98]).

CONCLUSIONS

DS with DES is safe and may be associated with better outcomes in selected patients. © 2016 Wiley Periodicals, Inc.

The Development of Robotic Technology in Cardiac and Vascular Interventions

Robotic technology has been used in cardiovascular medicine for over a decade, and over that period its use has been expanded to interventional cardiology and percutaneous coronary and peripheral vascular interventions. The safety and feasibility of robotically assisted interventions has been demonstrated in multiple studies ranging from simple to complex coronary lesions, and in the treatment of iliofemoral and infrapopliteal disease. These studies have shown a reduction in operator exposure to harmful ionizing radiation, and the use of robotics has the intuitive benefit of alleviating the occupational hazard of operator orthopedic injuries. In addition to the interventional operator benefits, robotically assisted intervention has the potential to also be beneficial for patients by allowing more accurate lesion length measurement, stent placement, and patient radiation exposure; however, more investigation is required to elucidate these benefits fully.

Restenosis of the Coronary Arteries: Past, Present, Future Directions

Restenosis is a pathologic response to vascular injury, characterized by neointimal hyperplasia and progressive narrowing of a stented vessel segment. Although advances in stent design have led to a dramatic reduction in the incidence of restenosis, it continues to represent the most common cause of target lesion failure following percutaneous coronary intervention. Efforts to maximize restenosis prevention, through careful consideration of modifiable risk factors and an individualized approach, are critical, as restenosis, once established, can be particularly difficult to treat. Novel approaches are on the horizon that have the potential to alter the natural history of this stubborn disease.

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.

Post-dilatation after implantation of bioresorbable everolimus- and novolimus-eluting scaffolds: an observational optical coherence tomography study of acute mechanical effects

OBJECTIVES

The objective was to investigate the acute mechanical effects of post-dilatation on bioresorbable scaffolds (BRS) as determined by optical coherence tomography (OCT).

BACKGROUND

Post-dilatation with high-pressure balloons is regarded as a key component of BRS implantation for treatment of coronary artery stenoses. However, the impact of post-dilatation on BRS in vivo has not been thoroughly investigated.

METHODS

OCT was performed after the implantation procedure of 51 everolimus-eluting or novolimus-eluting polylactic acid-based BRS with (n = 27) or without non-compliant balloon post-dilatation (n = 24). The number of malapposed struts, strut fractures, edge dissections, residual in-scaffold area stenosis, and incomplete scaffold apposition area was analyzed over the complete length of each BRS with a spacing of 1 mm.

RESULTS

OCT revealed a significantly lower incomplete scaffold apposition area if post-dilatation was performed (0.16 ± 0.49 mm² with post-dilatation vs. 2.65 ± 2.78 mm² without post-dilatation, p < 0.001), as well as a significantly lower absolute number of malapposed struts (1 ± 2 with post-dilatation vs. 13 ± 13 without post-dilatation, p < 0.001). No significant differences regarding residual in-scaffold area stenosis, strut fracture, edge dissection, symmetry index, or eccentricity index were observed in patients with vs. without post-dilatation.

CONCLUSION

Post-dilatation of BRS with non-compliant balloons significantly reduces the number of malapposed struts and incomplete scaffold apposition area without inducing higher rates of edge dissection or strut fracture.

Prevalence of parameters of suboptimal scaffold deployment following angiographic guided bioresorbable vascular scaffold implantation in real world practice - an optical coherence tomography analysis

AIM

To assess the prevalence of suboptimal bioresorbable vascular scaffold (BVS, Abbott Vascular, Santa Clara, California) deployment in real world practice with intracoronary optical coherence tomography (OCT) imaging.

METHODS

Consecutive patients who underwent percutaneous coronary intervention using BVS and the final optimization assessed with OCT imaging in two tertiary care centers between December 2012 and February 2015 were evaluated for parameters of suboptimal scaffold deployment by OCT.

RESULTS

Overall, 36 scaffolds were implanted in 27 patients during this period. Mean age of the population was 54.7±8.2years and 19 (70.4%) were type B2/C lesions. The prevalence of parameters of suboptimal scaffold deployment were: underexpansion-22(61.1%), geographic miss-3(8.3%), tissue prolapse-7(25.9%), scaffold pattern irregularity-1(2.8%), longitudinal elongation-7(38.8%). Of the 7 overlaps imaged: excessive overlap was observed in 3 and scaffold gap in one. The median duration of follow up was 679days (range 193-963days). There were four events during this period. None were associated with suboptimal scaffold deployment.

CONCLUSION

OCT based parameters of suboptimal scaffold deployment are common in real world scenario and were not associated with adverse outcomes on long term follow up. These findings need to be confirmed in larger studies.

Optical Coherence Tomography Predictors for Edge Restenosis After Everolimus-Eluting Stent Implantation

BACKGROUND

Stent edge restenosis (SER) remains a potential limitation of drug-eluting stents. The aim of this study was to determine optical coherence tomography (OCT) predictors for angiographic late SER after everolimus-eluting stent implantation.

METHODS AND RESULTS

We retrospectively analyzed 319 patients who underwent OCT immediately after everolimus-eluting stent implantation and scheduled 9- to 12-month follow-up angiography. The binary angiographic SER rate was 10% (32/319) in the patients, 8.4% (32/382) in lesions, and 4.4% (33/744) in stent edge segments. In the stent edge segments at post stenting, OCT-derived lipidic plaque (61% versus 20%; P<0.001) was more often observed in the SER group, and OCT-measured minimum lumen area (4.13±2.61 versus 5.58±2.46 mm²; P=0.001) was significantly smaller in the SER group compared with the non-SER group. Multivariate analysis identified lipidic plaque (odds ratio: 5.99; 95% confidence interval: 2.89-12.81; P<0.001) and minimum lumen area (odds ratio: 0.64; 95% confidence interval: 0.42-0.96; P=0.029) as independent predictors of binary SER. Receiver-operating characteristic analysis demonstrated that lipid arc of 185° (sensitivity: 71%; specificity: 72%; area under the curve: 0.761) and minimum lumen area of 4.10 mm² (sensitivity: 67%; specificity: 77%; area under the curve: 0.787) were optimal cutoff values for predicting ischemia-driven SER.

CONCLUSIONS

The present OCT study demonstrated that lipidic plaque and minimum lumen area in the stent edge segments at post stenting were associated with late SER after everolimus-eluting stent implantation. OCT provides valuable information to determine an appropriate landing zone for stent implantation.

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.

OCT-measured plaque free wall angle is indicative for plaque burden: overcoming the main limitation of OCT?

The aim of this study was to investigate the relationship between the plaque free wall (PFW) measured by optical coherence tomography (OCT) and the plaque burden (PB) measured by intravascular ultrasound (IVUS). We hypothesize that measurement of the PFW could help to estimate the PB, thereby overcoming the limited ability of OCT to visualize the external elastic membrane in the presence of plaque. This could enable selection of the optimal stent-landing zone by OCT, which is traditionally defined by IVUS as a region with a PB < 40 %. PB (IVUS) and PFW angle (OCT and IVUS) were measured in 18 matched IVUS and OCT pullbacks acquired in the same coronary artery. We determined the relationship between OCT measured PFW (PFWOCT) and IVUS PB (PBIVUS) by non-linear regression analysis. An ROC-curve analysis was used to determine the optimal cut-off value of PFW angle for the detection of PB < 40 %. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. There is a significant correlation between PFWOCT and PBIVUS (r(2) = 0.59). The optimal cut-off value of the PFWOCT for the prediction of a PBIVUS < 40 % is ≥220° with a PPV of 78 % and an NPV of 84 %. This study shows that PFWOCT can be considered as a surrogate marker for PBIVUS, which is currently a common criterion to select an optimal stent-landing zone.

Pathology of Endovascular Stents

Contemporary endovascular stents are the product of an iterative design and development process that leverages evolving concepts in vascular biology and engineering. This article reviews how insights into vascular pathophysiology, materials science, and design mechanics drive stent design and explain modes of stent failure. Current knowledge of pathologic processes is providing a more complete picture of the factors mediating stent failure. Further evolution of endovascular stents includes bioresorbable platforms tailored to treat plaques acutely and to then disappear after lesion pacification. Ongoing refinement of stent technology will continue to require insights from pathology to understand adverse events, refine clinical protocols, and drive innovation.

Relationship between left coronary artery bifurcation angle and restenosis after stenting of the proximal left anterior descending artery

INTRODUCTION

Restenosis after a percutaneous coronary intervention for proximal left anterior descending (pLAD) coronary artery disease remains a clinical challenge. However, the relationship between the left main trunk (LMT)/LAD bifurcation angle and the pLAD artery restenosis is unclear. This study examined the relationship between the LMT-LAD bifurcation angle and restenosis after stent implantation for pLAD disease.

METHODS

We analysed the data of 177 consecutive patients who underwent stent implantation for pLAD disease, followed by coronary angiography between December 2008 and September 2013. The LMT-LAD bifurcation angle was measured in the left or the right anterior oblique caudal (CAU) angiographic view.

RESULTS AND DISCUSSION

Out of 177 patients, 12 developed in-stent restenosis and 21 developed in-segment restenosis. The mean angle in patients with in-stent restenosis (52.2°±14.5°) in the left anterior oblique CAU view was significantly larger than that in patients without restenosis (32.0°±18.1°; P<0.001). The LMT-LAD angle in the right anterior oblique CAU view was significantly larger in patients with in-segment restenosis (27.3°±14.3°) than in patients without restenosis (17.5°±10.1°; P<0.001). Moreover, by multivariate analysis, the LMT-LAD angle was an independent predictor of in-stent and in-segment restenosis, after adjustment for significant confounders such as diabetes, hypertension, dyslipidaemia, final minimum lesion diameter and lesion length.

CONCLUSION

This study suggests that a wide LMT-LAD angle is a predictor of restenosis after stent implantation for pLAD artery disease.

Intravascular ultrasound-guided drug-eluting stent implantation: An updated meta-analysis of randomized control trials and observational studies

The use of intravascular ultrasound (IVUS) guidance for drug-eluting stent (DES) optimization is limited by the number of adequately powered randomized control trials (RCTs). We performed an updated meta-analysis, including data from recently published RCTs and observational studies, by reviewing the literature in Medline and the Cochrane Library to identify studies that compared clinical outcomes between IVUS-guided and angiography-guided DES implantation from January 1995 to January 2016. This meta-analysis included 25 eligible studies, including 31,283 patients, of whom 3192 patients were enrolled in 7 RCTs. In an analysis of all 25 studies, the summary results for all the events analyzed were significantly in favor of IVUS-guided DES implantation [major adverse cardiac events (MACE, odds ratio [OR] 0.76, 95% confidence intervals [CI]: 0.70-0.82, P<0.001); death (OR 0.62, 95% CI: 0.54-0.72, P<0.001); myocardial infarction (OR 0.67, 95% CI: 0.56-0.80, P<0.001); stent thrombosis (OR 0.58, 95% CI: 0.47-0.73, P<0.001); target lesion revascularization (TLR, OR 0.77, 95% CI: 0.67-0.89, P=0.005); target vessel revascularization (TVR, OR 0.85, 95% CI: 0.76-0.95, P<0.001)]. However, in a separate analysis of RCTs, a favorable result for IVUS-guided DES implantation was found only for MACE (OR 0.66, 95% CI: 0.52-0.84, P=0.001), TLR (OR 0.61, 95% CI: 0.43-0.87, P=0.006), and TVR (OR 0.61, 95% CI: 0.41-0.90, P=0.013). IVUS-guided percutaneous coronary intervention was associated with better overall clinical outcomes than angiography-guided DES implantation. However, in a solely RCT meta-analysis, this benefit was mainly driven by reduced rates of revascularizations.

The edge vascular response following implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold and the XIENCE V metallic everolimus-eluting stent. First serial follow-up assessment at six months and two years: insights from the first-in-man ABSORB Cohort B and SPIRIT II trials

AIMS

To assess serially the edge vascular response (EVR) of a bioresorbable vascular scaffold (BVS) compared to a metallic everolimus-eluting stent (EES).

METHODS AND RESULTS

Non-serial evaluations of the Absorb BVS at one year have previously demonstrated proximal edge constrictive remodelling and distal edge changes in plaque composition with increase of the percent fibro-fatty (FF) tissue component. The 5 mm proximal and distal segments adjacent to the implanted devices were investigated serially with intravascular ultrasound (IVUS), post procedure, at six months and at two years, from the ABSORB Cohort B1 (n=45) and the SPIRIT II (n=113) trials. Twenty-two proximal and twenty-four distal edge segments were available for analysis in the ABSORB Cohort B1 trial. In the SPIRIT II trial, thirty-three proximal and forty-six distal edge segments were analysed. At the 5-mm proximal edge, the vessels treated with an Absorb BVS from post procedure to two years demonstrated a lumen loss (LL) of 6.68% (-17.33; 2.08) (p=0.027) with a trend toward plaque area increase of 7.55% (-4.68; 27.11) (p=0.06). At the 5-mm distal edge no major changes were evident at either time point. At the 5-mm proximal edge the vessels treated with a XIENCE V EES from post procedure to two years did not show any signs of LL, only plaque area decrease of 6.90% (-17.86; 4.23) (p=0.035). At the distal edge no major changes were evident with regard to either lumen area or vessel remodelling at the same time point.

CONCLUSIONS

The IVUS-based serial evaluation of the EVR up to two years following implantation of a bioresorbable everolimus-eluting scaffold shows a statistically significant proximal edge LL; however, this finding did not seem to have any clinical implications in the serial assessment. The upcoming imaging follow-up of the Absorb BVS at three years is anticipated to provide further information regarding the vessel wall behaviour at the edges.

In-stent Restenosis

In-stent restenosis (ISR) is the narrowing of a stented coronary artery lesion. The mean time from percutaneous coronary intervention (PCI) to ISR was 12 months with drug-eluting stents (DES) and 6 months with bare metal stents (BMS). ISR typically presents as recurrent angina. The use of DES has significantly reduced the rate of ISR compared with BMS. Predictors of ISR include patient, lesion, and procedural characteristics. Intravascular ultrasound, optical coherence tomography, and fractional flow reserve are important tools for the anatomic and hemodynamic assessment of ISR. Treatment options for ISR include percutaneous coronary intervention with DES.

Classification of calcium in intravascular OCT images for the purpose of intervention planning

The presence of extensive calcification is a primary concern when planning and implementing a vascular percutaneous intervention such as stenting. If the balloon does not expand, the interventionalist must blindly apply high balloon pressure, use an atherectomy device, or abort the procedure. As part of a project to determine the ability of Intravascular Optical Coherence Tomography (IVOCT) to aid intervention planning, we developed a method for automatic classification of calcium in coronary IVOCT images. We developed an approach where plaque texture is modeled by the joint probability distribution of a bank of filter responses where the filter bank was chosen to reflect the qualitative characteristics of the calcium. This distribution is represented by the frequency histogram of filter response cluster centers. The trained algorithm was evaluated on independent ex-vivo image data accurately labeled using registered 3D microscopic cryo-image data which was used as ground truth. In this study, regions for extraction of sub-images (SI's) were selected by experts to include calcium, fibrous, or lipid tissues. We manually optimized algorithm parameters such as choice of filter bank, size of the dictionary, etc. Splitting samples into training and testing data, we achieved 5-fold cross validation calcium classification with F1 score of 93.7±2.7% with recall of ≥89% and a precision of ≥97% in this scenario with admittedly selective data. The automated algorithm performed in close-to-real-time (2.6 seconds per frame) suggesting possible on-line use. This promising preliminary study indicates that computational IVOCT might automatically identify calcium in IVOCT coronary artery images.

Angioplasty of unprotected left main coronary stenosis: Real world experience of a single-operator group from eastern India

Background

Coronary artery bypass graft surgery is the standard treatment of unprotected left main coronary stenosis (ULMCA). However, in the real world scenario, many of these patients are unfit for CABG or prefer angioplasty as an alternative when offered the choice.

Methods

A total of 86 clinically stable patients with ULMCA stenosis who were unfit or unwilling for CABG underwent PCI with DES at two tertiary care centers in Kolkata. Patients were followed up prospectively for a median of 34.6 months for major adverse cardiovascular events. Angiographic follow-up was done after 1 year of index procedure or earlier, if indicated.

Results

Fifty-five patients (64%) had distal left main stenosis. Two-stent technique was used in 19 patients (22%) and single-stent technique in 36 patients (42%) with distal left main lesion. Thirteen patients (15.1%) had left ventricular ejection fraction (LVEF) of ≤45%. There was no in-hospital death, MI, or stent thrombosis. During follow-up, major adverse cardiac event (MACE) occurred in 9 patients (10.5%). Our study revealed significantly greater MACE in patients with distal left main lesion with LVEF ≤45% (50% vs 6.38%, p = 0.0002), high SYNTAX score (36.36% vs 6.82%, p = 0.008), and diabetes (17.95% vs 0.00%, p = 0.07). Overall, also patients with Diabetes, LVEF ≤ 45%, and SYNTAX score >32 had significantly higher MACE. Use of IC Stent, IVUS, or procedural strategy in distal lesion did not affect MACE.

Conclusion

In selective patients with low-intermediate SYNTAX score and without diabetes and LV dysfunction, ULMCA PCI with DES is feasible.

Very Late Stent Thrombosis 11 Years after Implantation of a Drug-Eluting Stent

Very late stent thrombosis is an infrequent yet potentially fatal complication associated with drug-eluting stents. We report the case of an 88-year-old man who sustained an ST-segment-elevation myocardial infarction 11 years after initial sirolimus-eluting stent implantation. Optical coherence tomograms of the lesion showed that the focal incomplete endothelialization of the stent struts was the likely cause; neointimal formation, neoatherosclerosis, and late stent malapposition might also have contributed. To our knowledge, this is the longest reported intervening period between stent insertion and the development of an acute coronary event secondary to very late stent thrombosis. The associated prognostic and therapeutic implications are considerable, because they illuminate the uncertainties surrounding the optimal duration of antiplatelet therapy in patients who have drug-eluting stents. Clinicians face challenges in treating these patients, particularly when competing medical demands necessitate the discontinuation of antiplatelet therapy. In addition to the patient's case, we discuss factors that can contribute to very late stent thrombosis.