Intravascular ultrasound assessment of minimum lumen area and intimal hyperplasia in in-stent restenosis after drug-eluting or bare-metal stent implantation. The Nordic Intravascular Ultrasound Study (NIVUS)

Definition of Optimal Optical Coherence Tomography-Based Stent Expansion Criteria: In-Stent Minimum Lumen Area Versus Residual Stent Underexpansion

BACKGROUND

The mismatch between in-stent minimum lumen area (sMLA) and reference vessel lumen area, defined as stent underexpansion (SU), could be an important determinant of stent failure. We tested the clinical predictive value of absolute sMLA in comparison to relative SU in the context of the CLI-OPCI (Centro Per La Lotta Contro L'Infarto-Optimisation of Percutaneous Coronary Intervention) project registry.

METHODS

We retrospectively analyzed end procedural optical coherence tomography findings in 1211 patients (1422 lesions) undergoing percutaneous coronary intervention, assessing the prevalence and magnitude of residual SU and exploring correlation with outcome in comparison with sMLA.

RESULTS

In our series, both sMLA and SU were related to vessel size and anatomic lesion complexity. When compared with patients without adverse event at follow-up, those experiencing device-oriented cardiovascular events (composite of cardiac death, target vessel myocardial infarction, target lesion revascularization, and stent thrombosis) showed a lower sMLA (5.6±2.1 versus 6.1±2.1 mm²; P=0.011) but a comparable degree of SU (11.6±14.1% versus 11.2±13.3%; P=0.734). The prespecified cutoff value of sMLA <4.5 mm², documented in 23.8% of cases, was confirmed as independent outcome predictor for device-oriented cardiovascular events (hazard ratio [HR], 2.05 [95% CI, 1.5-2.9]) including target lesion revascularization (HR, 2.43 [95% CI, 1.7-3.5]) and stent thrombosis (HR, 3.23 [95% CI, 1.7-6.3]). A residual SU of 10%, 20%, and 30% was observed in 38.0%, 18.2%, and 7.6% of cases, respectively. No grade of residual SU significantly increased the risk of stent failure, unless if an SU >20% was associated with an sMLA <4.5 mm² (HR, 3.11 [95% CI, 1.7-5.6]). Finally, an association between stent overexpansion (ie, >110%) and device-oriented cardiovascular events was also observed (HR, 1.60 [95% CI, 1.1-2.3]).

CONCLUSIONS

Final absolute sMLA and not relative SU was associated with an increased risk of stent failure. A variable grade of SU was common, but it resulted in being clinically relevant only when associated with an sMLA <4.5 mm².

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.

Long-term outcomes of the modest stent expansion strategy for the culprit lesion of acute myocardial infarction

Slow flow during primary percutaneous coronary intervention (PCI) is a common complication. Our group showed that the stent (or post-balloon) diameter-to-vessel diameter ratio was inversely associated with slow flow phenomenon. We advocated the utility of modest stent expansion strategy, which was defined as the stent (or post-balloon) diameter-to-culprit vessel diameter ratio < 0.71, for prevention of slow flow phenomenon. This study aimed to compare the long-term outcomes in patients with acute myocardial infarction (AMI) between the modest stent expansion strategy and the aggressive stent expansion strategy (the stent diameter-to-culprit vessel diameter ratio ≥ 0.71). We included 584 AMI patients, which were divided 177 patients in the modest stent expansion group and 146 patients in the aggressive stent expansion group. The primary endpoint was major adverse cardiac events (MACE), which was defined as a composite of cardiac death, ischemia driven target vessel revascularization, and stent thrombosis. The slow flow after stent deployment was more frequently observed in the aggressive stent expansion group (24.0%) than in the modest stent expansion group (4.0%) (P < 0.001). The Kaplan-Meier curves revealed that MACE was comparable between the two groups (P = 0.64). The multivariate COX hazard model showed the non-significant association between the modest stent expansion strategy and MACE (vs. aggressive stent expansion: hazard ratio 1.005, 95% confidence interval 0.619-3.242, P = 0.41). In conclusion, the modest stent expansion strategy was not associated with long-term MACE. Therefore, the modest stent expansion strategy may be a good choice for the culprit lesion of AMI.

Association between coronary artery calcium score and in-stent restenosis after drug-eluting stent implantation

BACKGROUND

Coronary artery calcium (CAC) is a modifiable contributor of in-stent restenosis (ISR), but quantitative analyses using a noninvasive approach are limited. We aimed to investigate the associations between CAC score derived from ECG-gated coronary computed tomography angiography (CCTA) or non-gated non-contrast chest computed tomography (NCCT) and ISR.

METHODS

We included 368 lesions in 194 patients with coronary drug-eluting stent implantations in final analyses. CAC was quantified using the Agatston score. Primary endpoint was ISR, defined as lumen diameter stenosis over 50% at the stent segment or its proximal or distal edges (5-mm segments adjacent to the stent), at angiographic follow-up.

RESULTS

The CAC scores in either CCTA/2.5 mm group (r = 0.7702; P < 0.0001) or NCCT/5 mm group (r = 0.7105; P < 0.0001) were both correlated with in-stent diameter stenosis. The receiver-operating characteristic curve analysis identified a CAC score >245 in CCTA/2.5 mm group as the optimal ISR cutoff (sensitivity, 60.0%; specificity, 83.7%; area under the curve, 0.744; P < 0.001), and >209 in NCCT/5 mm group (sensitivity, 46.7%; specificity, 91.9%; area under the curve, 0.704; P < 0.001). Multivariable logistic regression models indicated a CAC score >245 in CCTA/2.5 mm group and >209 in NCCT/5 mm group independently associated with an 8.46- and 21.89-fold increase in ISR, respectively (all P < 0.01).

CONCLUSIONS

Either a CAC score >245 in CCTA/2.5 mm or >209 in NCCT/5 mm was significantly associated with increased risk in ISR.

Impact of intravascular ultrasound on Outcomes following PErcutaneous coronary interventioN for In-stent Restenosis (iOPEN-ISR study)

BACKGROUND

Percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) remains common. Intravascular imaging allows for the determination of the mechanism of ISR, potentially guiding appropriate therapy. Intravascular ultrasound (IVUS)-guided stent implantation is associated with a reduction in adverse events after PCI, but its impact on treatment of ISR is not clear.

METHODS

All patients with 1-year follow-up after ISR treatment from 2003 through 2016 were included and stratified by IVUS use. The primary endpoint was the rate of major adverse cardiac events (MACE) at 1 year, defined as the composite of all-cause mortality, Q-wave myocardial infarction, and target vessel revascularization (TVR).

RESULTS

The final analysis included 1522 ISR patients, 65.9% of whom were treated with IVUS guidance. The primary endpoint occurred in 18.0% of patients treated with IVUS guidance vs. 24.5% of patients treated with angiography guidance (p = 0.0014). Post-dilatation was used more often with IVUS (18.6% vs. 14.1%, p < 0.001), with a larger diameter of new stents (3.04 ± 0.35 mm vs. 2.94 ± 0.47 mm, p = 0.001). At 1 year, TVR occurred in 14.5% with IVUS guidance and 19.2% with angiography guidance (p = 0.021).

CONCLUSIONS

The use of IVUS is associated with decreased MACE at 1 year following PCI for ISR. These results support routine IVUS for the treatment of ISR lesions.

Adropin inhibits the phenotypic modulation and proliferation of vascular smooth muscle cells during neointimal hyperplasia by activating the AMPK/ACC signaling pathway

In-stent restenosis (ISR) remains an inevitable problem for some patients receiving drug-eluting stent (DES) implantation. Intimal hyperplasia is an important biological cause of ISR. It has been previously reported that adropin is a potentially protective factor in cardiovascular disease. Therefore, the present study investigated the function of adropin in inhibiting smooth muscle cell (SMC) phenotype modulation and proliferation, causing intimal hyperplasia. A total of 56 patients who visited the hospital consecutively (25 with ISR and 31 without ISR), who were followed up between April 2016 and March 2019, 1 year following DES, were analyzed to evaluate the association between in-stent neointimal volume and adropin serum levels. Rat aorta smooth muscle cells (RASMCs) were used to determine the effects of adropin on their phenotypic modulation and proliferation using western blot, MTT, PCR and immunofluorescence analyses. Adropin serum levels in the ISR group were significantly lower than those in the non-ISR group. Furthermore, linear regression analysis revealed that only adropin levels were negatively associated with neointimal volume in both groups. The overall adropin levels of the 56 patients and the percentages of neointimal volume revealed a strong negative association. In vitro, adropin suppressed angiotensin II (Ang II)-induced phenotypic modulation in RASMCs by restoring variations of osteopontin and α-smooth muscle actin. Furthermore, compared with the Ang II group, adropin markedly decreased the percentage of G₂/M-phase cells. Finally, adropin negatively regulated the phenotypic modulation and proliferation of RASMCs via the AMP-activated protein kinase/acetyl-CoA carboxylase (AMPK/ACC) signaling pathway. In conclusion, an independent, negative association was revealed between adropin and intimal hyperplasia; specifically, adropin inhibited the phenotypic modulation and proliferation of RASMCs by activating the AMPK/ACC signaling pathway. Therefore, adropin may be used as a potential predictor and therapeutic target for intimal hyperplasia and ISR.

Intravascular Ultrasound in Chronic Total Occlusion Percutaneous Coronary Intervention: Solving Ambiguity and Improving Durability

Chronic total occlusions remain among the most technically challenging lesions to treat percutaneously. Limitations of 2-dimensional angiography may further hinder successful treatment of these lesions. Intrasvascular ultrasound has a key role in percutaneous recanalization for a chronic total occlusion by providing key lesion characteristics, facilitating guidewire crossing, elucidating the intraplaque or extralaque path of the guidewire, optimizing lesion preparation, guiding stenting and identifying suboptimal results. Live visualization of the guidewire during crossing may reduce extraplaque wire tracking. This review describes the practical uses of intravascular imaging for commonly encountered scenarios when treating chronic total occlusions.

Procedural Characteristics and Outcomes of Patients Undergoing Percutaneous Coronary Intervention During Normal Work Hours Versus Non-work Hours

Percutaneous coronary intervention (PCI) performed during non-work hours is believed to have inferior outcomes because of operator fatigue, differences in baseline patient characteristics, and fewer on-call catheterization laboratory staff. We aimed to analyze a cohort of patients who underwent PCI (all comers) at our tertiary-care center between January 1, 2006, and December 31, 2018, and compare procedural and in-hospital outcomes between 2 groups defined by whether PCI was performed during normal work hours (7:00 A.M. to 7:00 PM) versus non-work hours (7:01 P.M. to 6:59 A.M. weekdays; all hours weekends and holidays). Finally, we examined temporal changes throughout the 24-hour weekday. Primary outcomes were unadjusted in-hospital adverse outcomes (composite death, recurrent myocardial infarction, emergent coronary artery bypass grafting, and target lesion revascularization). We identified 21,848 patients who underwent PCI at our institution. The proportions of ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) were higher during non-work hours. Overall, unadjusted in-hospital adverse outcomes were higher during non-work hours than during normal work hours (8.80% vs 2.00%; p <0.001). These findings were consistent based on the patient's clinical presentation (STEMI, NSTEMI, unstable angina, and stable angina). Despite confounding variables in the patients' presentations preventing definite causal attribution, our analysis demonstrates that in-hospital adverse outcomes were higher for those patients who underwent PCI (all comers) who had their procedures during non-work hours than during normal work hours.

Validation and comparison of drug eluting stent to bare metal stent for restenosis rates following vertebral artery ostium stenting: A single-center real-world study

BACKGROUND AND PURPOSE

While drug-eluting stents (DES) have been widely applicated in coronary stenosis, uncertainty persists concerning the relative performance and clinical benefit in patients undergoing vertebral artery stenting when compared with a bare metal stent (BMS). We sought to compare in-stent restenosis (ISR) rates of DES and BMS in the treatment of vertebral artery ostium (VAO) stenosis.

MATERIALS AND METHODS

This study analyzed a single-center prospective cohort. Over 1.5-year period (January 2014-June 2015), 137 consecutive patients underwent VAO stenting involving deployment of 76 DES and 74 BMS. Patient demographics, comorbidities, stenosis severity, stent diameters and lengths, periprocedural complications, imaging and duplex ultrasonography follow-up and recurrent symptoms were assessed.

RESULTS

Technical success was achieved in all patients. Mean VAO stenosis at presentation were 82.4 ± 7.2% in the DES group and 83.3 ± 7.5% in the BMS group and were reduced to 12.5 ± 4.5% and 11.3 ± 4.0%. Mean stent diameter was 3.53 ± 0.40 mm in DES and 5.05 ± 0.40 mm in BMS (p < 0.0001). Mean follow-up was 12.3 months for DES and 11.7 months for BMS. The use of DES was associated with significant lower ISR rates compared with BMS (18.4% vs. 31.1%; OR = 2.628, p = 0.021). Recurrent symptoms rates were similar in DES vs. BMS (2.6% vs 2.7%, p = 0.680). Stent type and stent diameter were independent risk factors for ISR (P = 0.026).

CONCLUSION

Our results suggest superior efficacy of deploying DES for the treatment of VAO stenosis with lower ISR rates as compared to BMS, but do not support significant differences in periprocedural risk and recurrent symptoms rate.

Neoatherosclerosis after drug-eluting stent implantation: a novel clinical and therapeutic challenge

The recognition that obstructive disease of the epicardial coronary arteries, causing ischaemic heart disease, can be treated with a percutaneous coronary intervention (PCI) has been a major discovery in cardiology in the last 40 years contributing, in particular, to the reduction of mortality associated to acute myocardial infarction (AMI). However, even in the era of drug-eluting stent (DES) implantation, a sizable proportion of patients who undergo PCI may develop late or very late post-implantation complications, that occur in the form of restenosis, neoatherosclerosis, and/or in-stent thrombosis. Such complications are clinically relevant since they can cause AMI and negatively impact on the outcome. The underlying pathophysiological mechanisms are complex but related to inhibition of neointimal proliferation by DES that, on the hand, reduces the rate of in-stent restenosis, but, on the other hand, causes dysfunctional vessel healing, persistent inflammation, platelet activation, and adverse immunological responses. Multiple approaches have been developed or are under evaluation to target DES-related complications including pharmacotherapy, procedure-related imaging methods, novel stent designs, and drug-delivery methods. The aim of this review is to provide an update on the latest preclinical, translational, and clinical pharmacotherapeutic developments in this setting that target novel cellular mechanisms and pathways that might contribute to neoatherosclerosis. Due to the importance of secondary prevention in the reduction of DES-associated complications, this review also provides a short overview of pharmacological agents that are established or currently being investigated in this regard.

Intravascular Ultrasound Assessment of In-Stent Restenosis in Saphenous Vein Grafts

Outcomes after percutaneous coronary interventions (PCI) in saphenous vein grafts (SVG) are inferior compared with native coronary arteries, but the mechanisms of SVG in-stent restenosis (ISR) have not been well-described. Thus, we aimed to evaluate the patterns of SVG ISR using intravascular ultrasound (IVUS) in 54 SVG ISR lesions. Stent underexpansion was defined as minimum stent area (MSA) <5 mm². The time from stent implantation to presentation with ISR (9 BMS, 18 first-generation DES, and 27 second-generation DES) was 3.7 ± 3.0 years. IVUS-defined ISR patterns were categorized as mechanical (33%) or biological (67%). Mechanical patterns comprised 10 cases of stent underexpansion (MSA = 4.2 ± 0.9 mm²), 6 stent fractures or deformations, and 2 uncovered aorto-anastomotic lesions. Biological patterns comprised 19 cases of neoatherosclerosis, 13 excessive neointimal hyperplasia (NIH, 65 ± 11%), and 4 thrombi. Compared with biological patterns of ISR, mechanical patterns were more frequently located at the SVG anastomosis (72% vs 39%, p = 0.04) and at the SVG hinge motion site (55% vs 21%, p = 0.02). Although patients with mechanical patterns of ISR presented earlier than those with biological patterns (2.3 vs 4.4 years, p = 0.009), 61% of them were diagnosed >1 year after stent implantation. In conclusion, SVG ISR is dominated by biological patterns including neoatherosclerosis. Mechanical patterns of SVG ISR are associated with earlier presentation and location at graft anastomosis or hinge motion site.

Arterial occlusions increase the risk of in-stent restenosis after vertebral artery ostium stenting

OBJECTIVE

The study was designed to investigate if vascular occlusion in the internal carotid artery (ICA) or the contralateral vertebral artery (VA) contribute to developing in-stent restenosis (ISR) in patients with vertebral artery ostium stenosis (VAOS).

METHODS

420 consecutive patients treated with VAOS stents (from a population of 8145 patients with VAOS) from January 2013 to December 2014 were analyzed in this retrospective study; 216 with drug eluted stents and 204 with bare metal stents. Based on pre-stent DSA findings, patients were divided into four groups: both carotid and vertebral arteries patent (PAT), ICA occlusion (ICA-OCC), contralateral VA occlusion (CVA-OCC), and combined occlusions (C-OCC). The incidence of ISR (stenosis >50%) was compared between groups using Cox regression analysis.

RESULTS

Of the 420 patients, the mean incidence of ISR was 36.4%, with a median 12 months of follow-up (IQR 3-12). Logistic regression analysis showed that drug eluting stent had less ISR than bare metal stent (OR=0.38, 95% CI 0.19 to 0.75, P=0.01). Cox regression analysis showed that CVA-OCC (HR=1.63, P=0.02) and C-OCC (HR=3.30, P=0.001) were risk factors for ISR but not ICA-OCC (P=0.31). In the CVA-OCC and C-OCC groups, in-stent peak systolic velocity (PSV) ≥140 cm/s, 1 day after successful stenting, was associated with subsequent development of ISR (OR=2.81, 95% CI 1.06 to 7.43, P=0.04).

CONCLUSION

Contralateral VA occlusion at the time of stenting increased the risk of ISR, especially if stent PSV on day 1 was >140 cm/s. Bare metal stents had more ISR than drug eluting stents.