Stent fracture and longitudinal compression detected on coronary CT angiography in the first- and new-generation drug-eluting stents

Incidence of coronary drug-eluting stent fracture: A systematic review and meta-analysis

Background

Reported evidence of coronary stent fracture (CSF) has increased in recent years. The purpose of this study was to determine reliable estimates of the overall incidence of CSF.

Methods and results

The MEDLINE, Embase and Cochrane databases were searched until March 18, 2022. Pooled estimates were acquired using random effects models. Meta-regression and subgroup analysis were used to explore sources of heterogeneity, and publication bias was evaluated by visual assessment of funnel plots and Egger’s test. Overall, 46 articles were included in this study. Estimates of CSF incidence were 5.5% [95% confidence interval (CI): 3.7–7.7%] among 39,953 patients based on 36 studies, 4.8% (95% CI: 3.1–6.8%) among 39,945 lesions based on 29 studies and 4.9% (95% CI: 2.5–9.4%) among 19,252 stents based on 8 studies. There has been an obvious increase in the incidence of CSF over the past two decades, and it seems that the duration of stent placement after stent implantation has no impact on incidence estimation.

Conclusion

The incidence of CSF was 5.5% among patients, 4.8% for lesions and 4.9% for stents and increased over the past 20 years. The duration of stent placement after stent implantation was found to have no impact on the incidence of CSF, but drug-eluting stent (DES) types and right coronary artery (RCA) lesions influenced the pooled incidence.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022311995], identifier [CRD42022311995].

Scoring model to predict low image quality of drug-eluting stent evaluated by computed tomography coronary angiography

Evaluation of in-stent restenosis (ISR) by computed tomography coronary angiography (CTCA) is less invasive but often impossible. We aimed to create a scoring model for predicting which drug-eluting stents (DES) cannot be evaluated with CTCA. We enrolled 757 consecutive implanted DES assessed with CTCA. Non-diagnostic evaluation was defined as poor/not evaluative by two different observers. These stents were randomly divided into a derivation (n = 379) and validation (n = 378) group. In the derivation group, we assessed predictors using logistic regression analysis and created a scoring model that would stratify non-diagnostic evaluation of DES-ISR. The validity of this scoring model was evaluated in the validation group using receiver-operating characteristic analysis. The percentage of non-diagnostic stents was 19/21% in the derivation/validation group (p = 0.71). Non-diagnostic evaluation was independently associated with implanted stent diameter (2.25-2.5. vs. 2.5-3 vs. > 3.0 mm), severe calcification, stent-in-stent lesion, and type of DES (stainless vs. CoCr vs. PtCr) in the derivation group. The predicting system of implanted DES non-diagnostic by CTCA (PIDENT) for non-diagnostic evaluation, including these four baseline factors, was derived (C-statistic = 0.86 in derivation group, cutoff: 8 points). The PIDENT score had a high predictive value for non-diagnostic DES in the validation model (C-statistic = 0.87, sensitivity 86%, specificity 74%, cutoff 8 points, p < 0.001). The PIDENT score, consisting of baseline characteristics including implanted stent diameter, severe calcification, stent-in-stent lesion, and type of DES, could identify non-diagnostic evaluation of DES-ISR with CTCA. The PIDENT score was valuable in reducing nonevaluable and meaningless CTCA for DES-ISR.

Comparison of Clinical Characteristics of Stent Thrombosis Between the Right Coronary Artery and the Left Coronary Artery - A Subanalysis of the REAL-ST Registry

BACKGROUND

Stent thrombosis (ST) remains a severe complication following stent implantation. We previously reported the risk factors for ST after 2nd-generation drug-eluting stent (DES) in the REAL-ST (Retrospective Multicenter Registry of ST After First- and Second-Generation DES Implantation) registry.

METHODS AND RESULTS

In this subanalysis, we aimed to reveal the difference in ST between right coronary (RCA) and left (LCA) coronary arteries. A total of 307 patients with ST were divided into the RCA-ST group (n=93) and the LCA-ST group (n=214). Multivariate analysis revealed younger age (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.93-0.99, P=0.01), ostial lesion at the time of index percutaneous coronary intervention (OR 4.37, 95% CI 1.43-13.33, P=0.01), bifurcation lesion at the time of index PCI (OR 0.05, 95% CI 0.02-0.12, P<0.01), chronic total occlusion (CTO) lesion at the time of index PCI indication (OR 4.19, 95% CI 1.05-16.71, P=0.04), and use of prasugrel at the time of ST (OR 7.30, 95% CI 1.44-36.97, P=0.02) were significantly associated with RCA-ST.

CONCLUSIONS

Younger age, ostial or CTO lesion, and use of prasugrel at the time of ST were prominent factors in RCA-ST, whereas bifurcation lesion was associated with LCA-ST. We should pay attention to the differences between RCA-ST and LCA-ST to prevent ST.

In-stent restenosis and longitudinal stent deformation: a case report

Background

Longitudinal stent deformation (LSD) is an infrequent complication of percutaneous coronary intervention (PCI), and it may lead to catastrophic clinical outcomes. However, reports of cardiac adverse events associated with LSD are rare.

Case presentation

A 55-year-old man with chest pain was treated for a severe left anterior descending branch (LAD)-diagonal 1 (D1) bifurcation lesion by PCI with two stents in the proximal LAD. LSD occurred during the withdrawal of the trapped D1 wire. High-pressure balloon dilatation was performed in the deformed stent, and the end-angiographic appearance was acceptable, but no additional corrective measures were implemented. Ten months later, the patient represented with acute coronary syndrome. Severe in-stent restenosis (ISR) had suboccluded the proximal LAD, and optical coherence tomography (OCT) visualized multilayered stent struts protruding into the lumen at the compressed segment of the stent. Following complete apposition with balloon dilation, a drug-coated balloon (DCB) was used to avoid an additional permanent metallic layer. He remained angina free, and the angiographic result demonstrated no residual stenosis at the six-month follow-up. To our knowledge, this case demonstrates the first report of ISR triggered by LSD in patients treated with DCBs under the guidance of OCT.

Conclusions

The current report underscores the importance of awareness of LSD, and OCT seems to be the preferred modality to confirm complete apposition. If left without performing additional corrective measures, LSD may be associated with a risk of ISR. Complete apposition with balloon dilation followed by a DCB is a feasible treatment option.

Long-term prognostic impact of non-invasive follow-up with computed tomography angiography in patients with left main coronary artery stenting

BACKGROUND

Left main coronary artery (LMCA) stenting is an evolving technique. Whether follow-up computed tomography angiography (CTA) might have clinical impact in these patients is controversial. The aim of present study is to compare clinical outcomes of patients with LMCA stenting followed with CTA versus patients with conventional clinical follow-up.

METHODS

From 2003 to 2014 all consecutive patients with unprotected LMCA stenosis treated with single DES implantation were prospectively included. Since 2009 all patients underwent CTA at 6-month after LMCA stenting. Therefore, the non-CTA group included all patients treated from 2003 to 2009 and the CTA group included patients treated from 2009 to 2014. Patients with 6-month cardiac events, renal dysfunction or atrial fibrillation were excluded. All patients underwent at least 2-year clinical follow-up. The primary endpoint was a composite of cardiac death, nonfatal myocardial infarction, and LMCA revascularization.

RESULTS

A total of 236 patients were included (119 in the non-CTA and 117 in the CTA group). Nine event-free patients presented with in-stent restenosis as assessed by CTA at 6 months; 5 had angiographic confirmation and were revascularized. At 2 years, the primary end-point was observed in 15.1% and 7.3% of patients of the non-CTA and CTA groups, respectively (P=0.07). All-cause mortality was higher in the non-CTA group (8.4% vs. 2.6%; P=0.05). Euroscore and CTA were found independent predictors of the primary end-point in the multivariate analysis.

CONCLUSIONS

Elective 6-month CTA after LMCA stenting is associated with better outcomes compared to conventional clinical follow-up.

Association of stent-induced changes in coronary geometry with late stent failure: Insights from three-dimensional quantitative coronary angiographic analysis

BACKGROUND

The relationship between vessel angulation and large changes in vessel geometry after stent implantation and the occurrence of stent failure still remains unclear. We sought to investigate the association of the change in the coronary bending angle after stenting and the risk for late stent failure by three-dimensional quantitative coronary angiography (3D QCA).

METHODS

The bending angle in coronary lesions that presented with late stent failure and those without stent failure was computed during the cardiac cycle, before and after stenting using a recently developed 3D QCA software.

RESULTS

A total of 40 lesions with stent failure (cases) were successfully matched to 47 lesions without stent failure (controls).The mean duration to follow-up coronary angiography was 1,011 days in cases and 1,109 days in the control group (P = 0.14). In stent failure, the systolic bending angle after stenting was smaller (14.45° [12.18, 17.68] versus 18.20° [14.00, 20.30], P = 0.01), while the stent-induced change in systolic bending angle was significantly larger (4.15° [1.13, 7.20] versus 1.80° [-1.90, 4.40], P = 0.004). Multivariable logistic regression analysis suggested that systolic bending angle after stenting (odds ratio: 0.88; 95% CI: 0.79-0.99; P = 0.03), and decrease in systolic bending angle after stenting (odds ratio: 1.13; 95% CI: 1.02-1.26; P = 0.03) were predictors of stent failure.

CONCLUSIONS

Our study suggests that a change in the natural tortuous course of the coronaries by stent implantation with the decrease in coronary bending angle is a potentially major contributor in stent failure.

Finite Element Analysis of the Implantation Process of Overlapping Stents

Overlapping stents are widely used in vascular stent surgeries. However, the rate of stent fractures (SF) and in-stent restenosis (ISR) after using overlapping stents is higher than that of single stent implantations. Published studies investigating the nature of overlapping stents rely primarily on medical images, which can only reveal the effect of the surgery without providing insights into how stent overlap influences the implantation process. In this paper, a finite element analysis of the overlapping stent implantation process was performed to study the interaction between overlapping stents. Four different cases, based on three typical stent overlap modes and two classical balloons, were investigated. The results showed that overlapping contact patterns among struts were edge-to-edge, edge-to-surface, and noncontact. These were mainly induced by the nonuniform deformation of the stent in the radial direction and stent tubular structures. Meanwhile, the results also revealed that the contact pressure was concentrated in the edge of overlapping struts. During the stent overlap process, the contact pattern was primarily edge-to-edge contact at the beginning and edge-to-surface contact as the contact pressure increased. The interactions between overlapping stents suggest that the failure of overlapping stents frequently occurs along stent edges, which agrees with the previous experimental research regarding the safety of overlapping stents. This paper also provides a fundamental understanding of the mechanical properties of overlapping stents.

Clinical, angiographic and procedural characteristics of longitudinal stent deformation

Recently, longitudinal stent deformation (LSD) has been reported increasingly. Even though the reported cases included almost all stent designs, most cases were seen in the Element™ stent design (Boston Scientific, Natick, MA, USA). It is considered that stent design, lesion and procedural characteristics play a role in the etiology of LSD. Yet, the effect of LSD on long-term clinical outcomes has not been studied well. Element stents implanted between January 2013 and April 2015 in our hospital were examined retrospectively. Patients were grouped into two according to the presence of LSD, and their clinical, lesion and procedural characteristics were studied. Twenty-four LSD's were detected in 1812 Element stents deployed in 1314 patients (1.83 % of PCI cases and 1.32 % of all Element stents). LMCA lesions (16.7 % vs 1.6 %, p < 0.001), complex lesions (75 % vs 35.1 %, p < 0.001), bifurcation lesions (37.5 % vs 18.3 %, p = 0.017), ostial lesions (33.3 % vs 12.8 %, p = 0.003), using of extra-support guiding catheter (54.2 % vs 22.3 %, p < 0.001) and extra-support guidewire (37.5 % vs 16.2 %, p = 0.005) were found to be more frequent in cases with LSD than in cases without it. In addition, the number of stents, stent inflation pressure and the use of post-dilatation were significantly different between the two groups. Two patients had an adverse event during the follow-up period. LSD is a rarely encountered complication, and is more common in complex lesions such as ostial, bifurcation and LMCA lesions. The use of extra-support guiding catheter, extra-support guidewires and low stent inflation pressure increases the occurrence of LSD. Nevertheless, with increased awareness of LSD and proper treatment, unwanted long-term outcomes can be successfully prevented.