Chronic stent recoil plays an important role in restenosis of the right coronary ostium

Ostial right coronary artery lesion morphology and outcomes after treatment with drug-eluting stents

BACKGROUND

Outcomes after percutaneous coronary intervention (PCI) for de novo ostial right coronary artery (RCA) lesions are poor.

AIMS

We used intravascular ultrasound (IVUS) to clarify the morphological patterns of de novo ostial RCA lesions and their associated clinical outcome.

METHODS

Among 5,102 RCA IVUS studies, 170 de novo ostial RCA stenoses (within 3 mm from the aorto-ostium) were identified. These were classified as 1) isolated ostial lesions (no disease extending beyond 10 mm from the ostium and without a calcified nodule [CN]); 2) ostial CN, typically with diffuse disease (disease extending beyond 10 mm); and 3) ostial lesions with diffuse disease but without a CN. The primary outcome was target lesion failure (TLF: cardiac death, target vessel myocardial infarction, definite stent thrombosis, and ischaemia-driven target lesion revascularisation).

RESULTS

The prevalence of an isolated ostial lesion was 11.8% (n=20), 47.6% (n=81) were ostial CN, and 40.6% (n=69) were ostial lesions with diffuse disease. Compared to ostial lesions with diffuse disease, isolated lesions were more common in women (75.0% vs 42.0%; p=0.01), and CN were associated with older age (median [first, third quartile] 76 [70, 83] vs 69 [63, 81] years old; p=0.002). The Kaplan-Meier rate of TLF at 2 years was significantly higher in patients with CN (21.6%) compared to diffuse lesions (8.2%) (p=0.04), and patients with isolated lesions had no events. A multivariable Cox proportional hazard model revealed that CN were significantly associated with TLF (hazard ratio 6.63, 95% confidence interval: 1.28-34.3; p=0.02).

CONCLUSIONS

Ostial RCA lesions have specific morphologies - detectable by IVUS - that may be associated with long-term clinical outcomes.

The everolimus eluting Synergy MegatronTM drug-eluting stent platform: Early outcomes from the European Synergy MegatronTM Implanters' Registry

BACKGROUND

The Synergy MegatronTM is an everolimus-drug eluting stent that may offer advantages in the treatment of aorto-ostial disease and large proximal vessels.

AIMS

To report the short- to medium-term clinical outcomes from the European Synergy MegatronTM Implanters' Registry.

METHODS

This registry was an investigator-initiated study conducted at 14 European centers. The primary outcome was target lesion failure (TLF), defined as the composite of cardiovascular death, target vessel myocardial infarction (MI), and target lesion revascularisation.

RESULTS

Five hundred seventy-five patients underwent PCI with MegatronTM between 2019 and 2021. Patients were 69 ± 12 years old, 26% had diabetes mellitus, 24% had moderate-severe left ventricular impairment and 59% presented with an acute coronary syndrome. 15% were deemed prohibitively high risk for surgical revascularisation. The target vessel involved the left main stem in 55%, the ostium of the RCA in 13% and was a true bifurcation (Medina 1,1,1) in 50%.  At 1 year, TLF was observed in 40 patients, with 26 (65%) occurring within the first 30 days. The cumulative incidence of TLF was 4.5% at 30 days and 8.6% (95% CI 6.3-11.7) at 1 year. The incidence of stent thrombosis was 0.5% with no late stent thromboses. By multivariate analysis, the strongest independent predictors of TLF were severe left ventricular impairment (HR 3.43, 95% CI: 1.67-6.76, p < 0.001) and a target vessel involving the left main (HR 4.00 95% CI 1.81-10.15 p = 0.001).

CONCLUSIONS

Use of the Synergy MegatronTM everolimus eluting stent in a 'real-world' setting shows favorable outcomes at 30 days and 1 year.

Mechanisms and treatment outcomes of ostial right coronary artery in-stent restenosis

BACKGROUND

Despite a high rate of in-stent restenosis (ISR) after stenting the right coronary artery (RCA) ostium, the mechanism of ostial RCA ISR is not well understood.

AIMS

We aimed to clarify the cause of ostial RCA ISR using intravascular ultrasound (IVUS).

METHODS

Overall, 139 ostial RCA ISR lesions were identified with IVUS, pre-revascularisation. Primary ISR mechanisms were classified as follows: 1) neointimal hyperplasia (NIH); 2) neoatherosclerosis; 3) ostium not covered by the stent; 4) stent fracture or deformation; 5) stent underexpansion (old minimum stent area <4.0 mm2 or stent expansion <50%); or 6) a protruding calcified nodule.

RESULTS

The median duration from prior stenting was 1.2 (first quartile 0.6, third quartile 3.1) years. The primary mechanisms of ISR were NIH in 25% (n=35) of lesions, neoatherosclerosis in 22% (n=30), uncovered ostium in 6% (n=9) (biological cause 53%, n=74), stent fracture or deformation in 25% (n=35), underexpansion in 11% (n=15), and protruding calcified nodules in 11% (n=15) (mechanical cause 47%, n=65). Including secondary mechanisms, 51% (n=71) of ostial RCA ISRs had stent fractures that were associated with greater hinge motion of the ostial-aorta angle during the cardiac cycle. The Kaplan-Meier rate of target lesion failure at 1 year was 11.5%. When the mechanically caused ISRs were treated without new stents, they suffered a higher subsequent event rate (41.4%) compared with non-mechanical causes or mechanical causes treated without restenting (7.8%, unadjusted hazard ratio 6.44, 95% confidence interval: 2.33-17.78; p<0.0001).

CONCLUSIONS

Half of the ostial RCA ISRs were due to mechanical causes. Subsequent event rates were high, especially in mechanically caused ISRs treated without the implantation of a new stent.

Coronary In-Stent Restenosis: JACC State-of-the-Art Review

The introduction and subsequent iterations of drug-eluting stent technologies have substantially improved the efficacy and safety of percutaneous coronary interventions. However, the incidence of in-stent restenosis (ISR) and the resultant need for repeated revascularization still occur at a rate of 1%-2% per year. Given that millions of drug-eluting stents are implanted each year around the globe, ISR can be considered as a pathologic entity of public health significance. The mechanisms of ISR are multifactorial. Since the first description of the angiographic patterns of ISR, the advent of intracoronary imaging has further elucidated the mechanisms and patterns of ISR. The armamentarium and treatment strategies of ISR have also evolved over time. Currently, an individualized approach using intracoronary imaging to characterize the underlying substrate of ISR is recommended. In this paper, we comprehensively reviewed the incidence, mechanisms, and imaging characterization of ISR and propose a contemporary treatment algorithm.

Effect of Hinge Motion on Stent Edge-Related Restenosis After Right Coronary Artery Treatment in the Current Drug-Eluting Stent Era

BACKGROUND

Stent edge-related restenosis (SER) remains a potential limitation of drug-eluting stent (DES). Hinge motion at the stent edge could lead to mechanical stress and contribute to incidents of SER. We investigated the effect of hinge motion on SER after implantation of current-generation DES in the right coronary artery (RCA), where excessive vessel movement is commonly observed.

METHODS AND RESULTS

Of 647 consecutive lesions in the RCA treated with second-generation or later DESs, 426 with follow-up angiography were included in this study. Intravascular imaging analysis was performed for 584 stent edges and reference segments. Binary restenosis occurred in 42 lesions (9.9%), and 55% were SERs. The hinge angle was significantly larger in the SER group than in the other restenosis or the no-restenosis group (17.9° vs. 11.6° and 10.6°, respectively; P<0.001). Lesions with an excessive hinge angle (>11.5°) had an increased rate of target lesion revascularization (19.1% vs. 7.2%; P<0.001) during the median follow-up period of 1,578 days. In per-edge analysis, hinge angle and residual plaque burden were independent predictors of SER. The coexistence of excessive hinge motion and residual plaque burden had a synergistic effect on stenotic progression in quantitative angiographic analysis (Pinteraction<0.001) at follow-up angiography.

CONCLUSIONS

Substantial stress determined by angulation at a stent edge and its interaction with residual plaque can be considered as one plausible mechanism for SER.

Predictors and outcomes of acute recoil after ultrathin bioresorbable polymer sirolimus-eluting stents implantation: an intravascular ultrasound in native coronary arteries

BACKGROUND

Ultrathin bioresorbable polymer sirolimus-eluting stents (BP-SESs) may easily lead to acute recoil. This study investigated acute recoil after BP-SES implantation on the basis of intravascular ultrasound (IVUS).

METHODS

We enrolled 40 consecutive stents. Absolute acute recoil by quantitative coronary angiography was defined as the difference between the mean diameter of the last inflated balloon (X) and mean lumen diameter of the BP-SES immediately after balloon deflation (Y). Percent (%) acute recoil was defined as (X-Y)×100/X. IVUS was performed within the culprit lesion. Plaque eccentricity, % plaque burden and calcification grade score were assessed using IVUS. Calcification grade was scored on the basis of quadrants. On the basis of the median acute recoil value of 5.0%, the stents were divided into two groups: low (LAR, n = 20) and high % acute recoil (HAR, n = 20).

RESULTS

Mean % acute recoil was 5.8 ± 5.3%. Plaque eccentricity, % plaque burden and stent/artery ratio were significantly higher in the HAR group than in the LAR group. Significant differences in % acute recoil were not observed regarding the types of stent diameter. In multivariate logistic regression and multiple linear regression analysis, plaque eccentricity and % plaque burden in the culprit plaque were significant positive predictors for the occurrence of % acute recoil. No significant differences, including clinical outcomes, were found between both groups at follow-up.

CONCLUSION

Acute recoil of BP-SESs may be influenced by an eccentric plaque with a large burden, which did not affect long-term outcomes. However, the present study might suggest the proper strategy (e.g. a more exhaustive plaque preparation) before BP-SES implantation in a case with these IVUS characteristics.

Clinical Outcomes after Additional Dynamic Renal® Stent Implantation for Stent Recoil in Ostial Coronary Lesions

Background: Interventional treatment of aorto-ostial coronary stenoses is limited by stent recoil and suboptimal angiographic results, leading to restenosis and frequent re-interventions. As a potential bail-out strategy for stent recoil, implantation of an additional stent to increase radial force has been reported. Thus, we sought to investigate clinical outcomes after additional implantation of a Dynamic Renal^® stent (DRS), a non-coronary; bare-metal stent with very high radial force, in aorto-ostial coronary stenoses. Methods: Patients treated by implantation of DRSs for stent recoil in the ostial right coronary artery or the left main stem were identified from the hospital database. Baseline clinical and procedural characteristics were compared to patients who underwent re-intervention for in-stent-restenosis in similar segments by either implantation of conventional drug-eluting stents (DES) or paclitaxel-coated balloons (PCB). Clinical follow-ups were performed up to three years following re-intervention with the assessment of death, target lesion reintervention (TLR), and major adverse cardiac events (MACE) as a combination death, myocardial infarction and target vessel revascularization. Kaplan–Meier analyses were performed for event-free survival between the three groups. Results: Between 05/2013 and 07/2019, 28 patients underwent DRS implantation of aorto-ostial coronary lesions. In comparison with 49 patients with DES implantation and 29 patients undergoing PCB treatment, no relevant differences in baseline parameters were identified. Median follow-up was 714 days, with an available follow-up of >1 year after intervention in 82.1% of patients. In the entire study cohort at two years after re-intervention, the TLR rate was 16% (17 patients), the MACE rate 37% (39 patients), and all-cause mortality 9% (10 patients), with no significant differences between the three groups. Conclusions: DRS implantation for treating stent recoil of aorto-ostial coronary lesions resulted in a high rate of TLR, and was associated with similar risk for death and MACE compared to treatment of in-stent-restenosis with DES or PCB. Randomized, larger comparisons of contemporary DES in patients exclusively presenting with stent recoil are necessary to further define the efficacy and safety of this approach.

Procedural Outcomes of Patients Undergoing Percutaneous Coronary Intervention for De Novo Lesions in the Ostial and Proximal Left Circumflex Coronary Artery

Ostial coronary artery lesions can be challenging during percutaneous coronary intervention (PCI) because of elastic fiber content, calcium burden, and angulation. We assessed procedural and clinical major adverse cardiac events (MACE) associated with PCI for ostial lesions, focusing on ostial left circumflex (LC) lesions compared with ostial left anterior descending artery (LAD) and right coronary artery lesions. All patients with ostial or very proximal coronary artery lesions treated with PCI at MedStar Washington Hospital Center (Washington, DC) from 2003 to 2018 were included. The primary end point was target lesion revascularization (TLR)-MACE, defined as the composite of all-cause mortality, Q-wave myocardial infarction (MI), and TLR at 1 year. A total of 4,759 patients with available 1-year follow-up were included: 2,236 ostial/very proximal LAD, 980 ostial/very proximal LC, and 1,543 ostial/very proximal right. The presenting clinical syndrome for the LC group was mainly stable or unstable angina, whereas MI was more common in the LAD. At 1 year, the TLR-MACE rate was 16.7% in the LC group versus 12.5% in the LAD and 11.8% in the right group (p = 0.001). Mortality rates were 11.2% in the LC group versus 8.4% in the LAD and 6% in the right group (p <0.001). A Cox model showed that dialysis had the highest impact on TLR-MACE. In conclusion, compared with PCI of ostial or very proximal LAD or right lesions, PCI of ostial or very proximal LC lesions was associated with higher rates of TLR-MACE.

Endovascular treatment of the vertebral artery origin stenosis by using the closed-cell, self-expandable Carotid Wallstent

BACKGROUND

Endovascular treatment has been considered a good alternative to surgery for symptomatic vertebral artery origin stenosis (VAOS) due to the high risk of morbidity associated with surgery. The purpose of this study was to evaluate the feasibility and efficacy of insertion of the closed-cell, self-expandable Carotid Wallstent for the treatment of VAOS.

METHODS

The records of 72 patients with VAOS refractory to adequate medication who were treated by endovascular treatment with the Carotid Wallstent from December 2006 to November 2018 were retrospectively evaluated.

RESULTS

Of the 72 patients, 43 presented with transient ischemic attacks. Forty-seven patients (65.3%) manifested other brachiocephalic stenoses; of these, 40 patients had occlusion, hypoplasia, or stenosis of the contralateral vertebral artery. Overall technical success (defined as 20% or less residual stenosis) was 100%. Procedure-related complications (n = 8, 11.1%) included sudden asystole (n = 1), acute in-stent thrombosis (n = 3), minor stroke (n = 3), and stent shortening (n = 1). All complications were resolved without permanent neurological deficit. Angiographic follow-up (mean, 13.0 months) was achieved in 49 patients and revealed in-stent restenosis in 1 patient (2.0%) and stent malposition by shortening in 2 patients (4.1%). Follow-up records were available in 57 patients (mean 15.6 months). Three of the 57 patients (n = 3, 5.3%) had recurrent symptoms of vertebrobasilar ischemia and none was retreated.

CONCLUSIONS

Endovascular treatment of symptomatic VAOS using the closed-cell, self-expandable Carotid Wallstent is technically feasible and effective in alleviating patient symptoms and for improving vertebrobasilar blood flow.

In-Hospital Outcomes After Recanalization of Ostial Chronic Total Occlusions

BACKGROUND

Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) still remains a major challenge in interventional cardiology. Recanalization of ostial lesions is challenging and complex. This present study aims to evaluate the outcome of patients with ostial and non-ostial CTO-PCI with regard to acute, in-hospital outcome.

METHODS

Between 2012 and 2018 we included 600 patients. Ostial lesions (OL) were defined as a coronary arterial stenosis within 3 mm of the vessel origin. Antegrade and retrograde CTO-PCI techniques were used and a composite safety endpoint comprising in-hospital death, vascular complications, cardiac tamponade, stroke and acute myocardial infarction.

RESULTS

The majority of the patients were male (82.3%) and the mean age was 62.1 years (±10.3 years). The right coronary artery (RCA) was the most frequent target vessel in 58.5%, followed by the left circumflex artery (LCX) (15.4%) and the left anterior descending artery (LAD) (26.2%). The success (p = .439) and complication rates (p = .169) were independent of the target vessel. We determined that examination and fluoroscopy time were longer in patients with OL (120.7 min vs. 99.0 min, p < .001 and 44.9 min vs. 34.5 min, p < .001) and that in this group of patients the retrograde approach was used more frequent (38.8% vs. 18.2%, p < .001). Overall success rates were lower in OL than compared to NOL (74.6% vs. 86.5%, p = .016).

CONCLUSIONS

Our retrospective study suggests that recanalization of ostial CTO lesions is associated with reduced PCI success rates as well as long examination and high fluoroscopy times.

Clinical impact of the gap-angle ratio in patients with ostial lesions of the right coronary artery undergoing percutaneous coronary intervention

The aim of this study was to investigate the incidence of binary restenosis and its predictors in patients with ostial lesions of the right coronary artery (RCAos) who underwent percutaneous coronary intervention (PCI). RCAos are associated with a high incidence of restenosis, and the implantations of drug-eluting stents for RCAos have not been fully elucidated. The study participants included 75 patients (72.3 ± 9.5 years, 72% men) who underwent PCI for RCAos at our institution between November 2001 and May 2017. The angle between the greater curvature of the aortic wall and the right coronary artery take-off in the diastolic and systolic phases in the left anterior oblique position view was investigated. Clinical outcome was defined as binary restenosis at follow-up coronary angiography. We also evaluated target lesion failure (TLF) defined as a composite of cardiac mortality, target vessel myocardial infarction, and target lesion revascularization (TLR). The incidence of binary restenosis was 48.0% (n = 36) of the entire cohort. The incidence of TLF was 49.3% (n = 37) of the entire cohort, which was mainly driven by TLR (36.0%, n = 27). The area under the curve of the gap-angle ratio [(difference between the maximum and minimum angles)/(minimum angle); GAR] for binary restenosis was 0.73, and the cutoff value was 0.306 (sensitivity 67%, specificity 82%). The patients were divided into two groups: a low-GAR (< 0.306; n = 30) and high-GAR group (> 0.306; n = 45). Binary restenosis was more frequent in the high-GAR group than in the low-GAR group (76.7% vs. 28.9%, p = 0.007). The cumulative rate of TLF was significantly higher in the high-GAR group when compared with the low-GAR group (53.3% vs. 40.0%, p = 0.01), which was mainly driven by TLR (56.7% vs. 22.2%, p = 0.01). High-GAR (> 0.306) [OR 2.66 (1.34-5.31), p = 0.005] and stent under expansion [OR 2.37 (1.10-5.11), p = 0.03] were found to be independent predictors of binary restenosis after adjustment for multiple confounders. Multivariable analysis also revealed that high-GAR (> 0.306) [OR 2.06 (1.02-4.14), p = 0.03] and stent under expansion [OR 2.82 (1.28-6.19), p = 0.01] were independent predictors of TLF. We suggest that GAR (> 0.306) predicts binary restenosis and TLF in patients undergoing PCI for RCAos.

GuideLiner extension catheter-facilitated side strut stenting technique for the treatment of right coronary artery ostial in-stent restenosis

Percutaneous coronary intervention (PCI) for the treatment of right coronary artery (RCA) ostial in-stent restenosis (ISR) can be challenging. The technical difficulties are compounded by excessive stent protrusion into the aorta, preventing coaxial engagement of the guiding catheter and wiring through the central stent lumen. Through this review, we aim to highlight the practical challenges encountered during the treatment of ostial RCA ISR through PCI and evaluate the various interventional techniques that have been used. We describe the first reported case of a GuideLiner extension catheter-facilitated side-strut stenting for the treatment of ostial RCA ISR and demonstrate the safety and feasibility of this novel technique.

Independent predictors of in-stent restenosis after drug-eluting stent implantation for ostial right coronary artery lesions

OBJECTIVES

We evaluated the angiographic patterns and predictors of in-stent restenosis (ISR) for ostial lesions of the right coronary artery (RCA) to clarify the mechanism of insoluble restenosis.

BACKGROUND

Although ISR of the RCA still occurs, limited data is available regarding the associated angiographic findings.

METHODS

Between January 2005 and September 2013, we recruited consecutive patients undergoing routine angiography 6-18months after implantation of a drug-eluting stent (DES). Multiple logistic regression analysis was used to determine the independent predictors of ISR, and the adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) were calculated.

RESULTS

Routine angiography revealed that 45 of 131 patients (34.3%) had RCA-ISR, which were classifiable by occlusion type into ostial (24 cases), proximal (17 cases), diffuse (3 cases), and total (1 case). By multivariable analysis, early generation DES was the only independent predictor of overall ISR (aOR, 3.54; 95% CI, 1.59-7.87; p=0.002). In a subgroup analysis of each focal ISR pattern, early generation DES (aOR, 7.76; 95% CI, 2.15-28.0; p=0.002) was associated with increased risk of ostial ISR. On the contrary, larger stent (aOR, 0.21; 95% CI, 0.05-0.84; p=0.027) was associated with decreased risk of ostial ISR. Furthermore, a ratio of the stent to post-balloon size >1.10 (aOR, 3.93; 95% CI, 1.30-11.8; p=0.002) and good left ventricular contractility (ejection fraction >60%) (aOR, 8.27; 95% CI, 1.76-39.0; p=0.008) were associated with increased risk of proximal ISR when stent fracture was observed.

CONCLUSION

The focal pattern of RCA-ISR was mostly observed after DES implantation, and the mechanisms of proximal and ostial ISR differed.

Paclitaxel-coated balloon catheter compared with drug-eluting stent for drug-eluting stent restenosis in routine clinical practice

AIMS

The aim of this study was to compare the efficacy between paclitaxel-coated balloon (PCB) and drug-eluting stent (DES) implantation for the treatment of DES restenosis in complex situations.

METHODS AND RESULTS

Data of patients who received revascularisation for DES restenosis between 2004 and 2011 were collected. A total of 683 patients with 777 lesions were analysed in this study (306 lesions treated by PCB, 471 lesions by DES). The use of PCB or DES was at the discretion of the operator. Angiographic outcomes at six to eight months and clinical outcomes at 12-month follow-up were compared between groups. The primary outcome was binary restenosis. Cox regression analysis with propensity score adjustment suggested that there were no significant differences between the two groups with respect to binary restenosis, target lesion revascularisation (TLR), and major adverse cardiac events. As for the angiographic endpoints, subgroup analysis was performed for several parameters. There was a significant trend favouring PCB with respect to binary restenosis and TLR in non-focal type lesions and bifurcation lesions.

CONCLUSIONS

Angiographic and clinical outcomes in the PCB group were similar to those in the repeat DES group. PCB seemed to offer more favourable results in non-focal type lesions and bifurcation lesions.

Incidence, predictive factors, and clinical impact of stent recoil in stent fracture lesion after drug-eluting stent implantation

BACKGROUND

Stent fracture (SF) after drug-eluting stent (DES) implantation was reported to be associated with target lesion revascularization (TLR). We have noted abnormal late acquired stent axial deformation in lesions after DES implantation, especially in SF lesions, and defined it as stent recoil (SR). We evaluated the incidence, predictive factors, and clinical impact of SR in SF lesions.

METHODS

Between 2003 and 2012, 5456 patients (11,712 lesions) underwent DES implantations and follow-up angiography within one year after the index procedure. SR was defined as an axial recoil deformation less than 80% of the stent diameter and SF was defined as the separation of stent segments or stent struts. SF and SR were confirmed by follow-up angiography. The primary endpoint was defined as clinically driven TLR.

RESULTS

SF was observed in 494 lesions (4.2%) and SR in 138 of SF lesions (27.9%). According to multinomial logistic regression analyses, severe calcification and ostial lesion in the right coronary artery were stronger predictive factors of SF with SR lesions. The cumulative incidences of any and clinically driven TLR at 5years were both significantly higher in the SF with SR group than in the SF without SR group (51.7% versus 35.0%, P<0.001; 22.2% versus 12.8%, P=0.019; respectively).

CONCLUSIONS

SR in SF lesions after DES implantation could be related to the lesion characteristics. SF with SR was highly associated with subsequent TLR compared with SF without SR.

Impact of intravascular ultrasound on the long-term clinical outcomes in the treatment of coronary ostial lesions

OBJECTIVES

To evaluate the long-term outcomes of patients with ostial lesions who underwent percutaneous coronary intervention (PCI) with and without the use of intravascular ultrasound (IVUS).

BACKGROUND

A higher rate of adverse cardiac events is associated with PCI of ostial lesions as compared with nonostial disease.

METHODS

From 7/2002 to 8/2010, 225 patients with 233 coronary ostial lesions underwent PCI with (n = 82) and without (n = 143) IVUS guidance. Ostial lesions included both native aorto-ostial or major coronary vessel (left anterior descending, left circumflex, and ramus intermedius) lesions. Clinical outcomes [cardiovascular death, myocardial infarction (MI), and target lesion revascularization (TLR)] at a mean follow-up of 4.2 ± 2.5 years were compared between patients undergoing PCI of an ostial lesion with and without use of IVUS using univariate and propensity score adjusted analyses.

RESULTS

Aorto-ostial lesions (n = 109) comprised 47% of lesions, whereas the remaining lesions (53%) involved major coronary vessels. After propensity score adjustment, IVUS use was associated with lower rates of the composite of cardiovascular death, MI, or TLR (HR 0.54, 95% CI 0.29-0.99; P = 0.04), composite MI or TLR (HR 0.39, 95% CI 0.18-0.83; P = 0.01), and MI (HR 0.31, 95% CI 0.11-0.85; P = 0.02) as compared with no IVUS. The use of IVUS was also associated with a trend towards a lower rate of TLR (HR 0.42, 95% CI 0.17-1.02; P = 0.06).

CONCLUSIONS

PCI of coronary ostial lesions with the use of IVUS was associated with significantly lower rates of adverse cardiac events.

Microwave spectrometry for the evaluation of the structural integrity of metallic stents

PURPOSE

To assess the feasibility of a method based on microwave spectrometry to detect structural distortions of metallic stents in open air conditions and envisage the prospects of this approach toward possible medical applicability for the evaluation of implanted stents.

METHODS

Microwave absorbance spectra between 2.0 and 18.0 GHz were acquired in open air for the characterization of a set of commercial stents using a specifically design setup. Rotating each sample over 360°, 2D absorbance diagrams were generated as a function of frequency and rotation angle. To check our approach for detecting changes in stent length (fracture) and diameter (recoil), two specific tests were performed in open air. Finally, with a few adjustments, this same system provides 2D absorbance diagrams of stents immersed in a water-based phantom, this time over a bandwidth ranging from 0.2 to 1.8 GHz.

RESULTS

The authors show that metallic stents exhibit characteristic resonant frequencies in their microwave absorbance spectra in open air which depend on their length and, as a result, may reflect the occurrence of structural distortions. These resonances can be understood considering that such devices behave like dipole antennas in terms of microwave scattering. From fracture tests, the authors infer that microwave spectrometry provides signs of presence of Type I to Type IV stent fractures and allows in particular a quantitative evaluation of Type III and Type IV fractures. Recoil tests show that microwave spectrometry seems able to provide some quantitative assessment of diametrical shrinkage, but only if it involves longitudinal shortening. Finally, the authors observe that the resonant frequencies of stents placed inside the phantom shift down with respect to the corresponding open air frequencies, as it should be expected considering the increase of dielectric permittivity from air to water.

CONCLUSIONS

The evaluation of stent resonant frequencies provided by microwave spectrometry allows detection and some quantitative assessment of stent fracture and recoil in open air conditions. Resonances of stents immersed in water can be also detected and their characteristic frequencies are in good agreement with theoretical estimates. Although these are promising results, further verification in a more relevant phantom is required in order to foresee the real potential of this approach.

Preventable effects of bare-metal stent on restenosis after everolimus-eluting stent deployment

This case report describes a patient who underwent implantation of a bare-metal stent (BMS) for the treatment of everolimus-eluting stent (EES) restenosis caused by chronic stent recoil, and the BMS successfully escaped from duplicate restenosis and target lesion revascularization (TLR).

Sirolimus-eluting stent implantation for ostial right coronary artery lesions: five-year outcomes from the j-Cypher registry

Ostial right coronary artery (RCA) lesions are associated with a high restenosis rate after bare-metal stent implantation. However, long-term outcomes after drug-eluting stent (DES) implantation for ostial RCA lesions have not been adequately evaluated. Among 12824 patients enrolled in the j-Cypher registry, 5-year outcomes were compared between 397 patients with ostial RCA lesions, and 3716 patients with non-ostial RCA lesions treated with sirolimus-eluting stents (SES). Through 5-year follow-up, patients with ostial RCA lesions had a significantly higher cumulative incidence of target lesion revascularization (TLR) (28.2 versus 13.7 %, P < 0.0001) than those with non-ostial RCA lesions. After adjusting for confounders, excess TLR risk of the ostial group relative to the non-ostial group was significant for both early TLR within 1-year and late TLR beyond 1-year (HR 2.14 [95 % CI 1.59-2.84], P < 0.0001, and HR 1.58 [95 % CI 1.06-2.26], P = 0.02, respectively). Although the cumulative incidence of death was also significantly higher in the ostial group than in the non-ostial group (25.7 versus 14.4 %, P < 0.0001), the excess risk of the ostial group relative to the non-ostial group was no longer significant after adjusting for confounders (HR 1.25 [95 % CI 0.99-1.57], P = 0.07). SES implantation for ostial RCA lesions was associated with higher risk for TLR as compared with that for non-ostial RCA lesions. Restenosis, both early and late, remains an issue in coronary DES implantation for ostial RCA lesions.

Intravascular ultrasound assessment of drug-eluting stent coverage of the coronary ostium and effect on outcomes

When stenting an ostial or proximal coronary lesion, 1 fundamental decision is whether to extend the proximal end of the stent into the aorta (in the case of the left main [LM] or right coronary ostium) or into the polygon of confluence of the LM (in the case of the left anterior descending [LAD] ostium). Complete angiographic and intravascular ultrasound data and 9-month follow-up angiographic and clinical data were available from 459 patients with 138 ostial lesions (angiographic diameter stenosis within the ostium of ≥50%) or 321 nonostial lesions in which the proximal end of the stent ended at or near the coronary ostium. Strut protrusion was more frequent in the LM than in the right or LAD ostium (68% vs 59% vs 53%, p = 0.010). The length of strut protrusion was 3.4 ± 1.7 mm in the LM ostium, 1.7 ± 1.0 mm in the LAD ostium, and 2.4 ± 1.4 mm in the right ostium (p = 0.001). In contrast, incomplete stent coverage of the ostium was similar among the LM, LAD, and right coronary artery (23% vs 33% vs 28%, p = 0.084) with a residual uncovered segment plaque burden of 42 ± 11%. Ostial restenosis was similar between the lesions with versus without strut protrusion (3.2% vs 2.3%, p = 0.775) and between the lesions with incomplete versus complete stent coverage of the ostium (2.4% vs 3.0%, p = 0.100). Ostial restenosis was seen in only 2 of 61 lesions (3.3%) with acute malapposition. In conclusion, when treating an ostial or proximal coronary artery lesion with a drug-eluting stent, the decision of whether to protrude the proximal end of the stent or leave the ostium uncovered does not appear to be critical.

Comparison of bare-metal stents and drug-eluting stents in coronary ostial lesions (from the National Heart, Lung, and Blood Institute Dynamic Registry)

We compared the effectiveness of drug-eluting stents (DESs) to bare-metal stents (BMSs) in ostial lesions from an unrestricted patient cohort with 3-year follow-up. DESs have proved more effective at decreasing repeat revascularization rates compared to BMSs in patients with uncomplicated coronary artery disease. Whether DESs provide similar benefits in ostial lesions is not clearly defined. We analyzed data from 775 patients in the National, Heart, Lung, and Blood Institute Dynamic Registry undergoing stenting of ostial lesions with DESs or BMSs. Patients were followed for 3 years for the occurrence of myocardial infarction (MI), repeat revascularization (coronary bypass surgery/repeat percutaneous coronary intervention), and death. In total 439 patients had 464 ostial lesions treated with BMSs and 336 patients had 351 ostial lesions treated with DESs. Adjusted DES versus BMS 3-year hazard ratios were 1.03 (95% confidence interval 0.60 to 1.78, p = 0.90) for death, 1.40 (0.83 to 2.37, p = 0.21) for MI, and 0.81 (0.59 to 1.11, p = 0.19) for repeat revascularization. In patients undergoing percutaneous coronary intervention for aorto-ostial disease (n = 200), death and repeat revascularization did not differ between stent types, but DES-treated patients had more MI during follow-up. For coronary ostial disease (n = 574), 3-year observed rates of death or MI did not differ; however, repeat revascularization was more common in the BMS group. In conclusion, use of DESs for ostial lesions was associated with no difference in the hazard of death, MI, or overall rates of repeat revascularization compared to BMS use.

Comparison of long-term clinical and angiographic outcomes following implantation of bare metal stents and drug-eluting stents in aorto-ostial lesions

Percutaneous coronary intervention (PCI) to aorto-ostial (AO) lesions is technically demanding and associated with high revascularization rates. The aim of this study was to assess outcomes after bare metal stent (BMS) compared to drug-eluting stent (DES) implantation after PCI to AO lesions. A retrospective cohort analysis was conducted of all consecutive patients who underwent PCI to AO lesions at 2 centers. Angiographic and clinical outcomes in 230 patients with DES from September 2000 to December 2009 were compared to a historical control group of 116 patients with BMS. Comparison of the baseline demographics showed more diabetics (32% vs 16%, p = 0.001), lower ejection fractions (52.3 ± 9.7% vs 55.0 ± 11.5%, p = 0.022), longer stents (17.55 ± 7.76 vs 14.37 ± 5.60 mm, p <0.001), and smaller final stent minimum luminal diameters (3.43 ± 0.53 vs 3.66 ± 0.63 mm, p = 0.001) in the DES versus BMS group. Angiographic follow-up (DES 68%, BMS 66%) showed lower restenosis rates with DES (20% vs 47%, p <0.001). At clinical follow-up, target lesion revascularization rates were lowest with DES (12% vs 27%, p = 0.001). Cox regression analysis with propensity score adjustment for baseline differences suggested that DES were associated with a reduction in target lesion revascularization (hazard ratios 0.28, 95% confidence interval 0.15 to 0.52, p <0.001) and major adverse cardiac events (hazard ratio 0.50, 95% confidence interval 0.32 to 0.79, p = 0.003). There was a nonsignificantly higher incidence of Academic Research Consortium definite and probable stent thrombosis with DES (n = 9 [4%] vs n = 1 [1%], p = 0.131). In conclusion, despite differences in baseline characteristics favoring the BMS group, PCI with DES in AO lesions was associated with improved outcomes, with lower restenosis, revascularization, and major adverse cardiac event rates.

Sirolimus-eluting versus bare-metal stent implantation in patients with ostial lesions

INTRODUCTION

To investigate the efficacy of implantation of sirolimus-eluting stents (SES) in the ostium of coronary arteries.

METHODS

We assigned 96 patients with lesions located in ostias of the coronary circulation to receive a SES or a bare-metal stent (BMS).

RESULTS

At follow-up the late lumen loss was 0.07 mm in the SES versus 1.06 mm in the BMS group (p<0.001); -0.04 mm versus 0.11 mm (p = 0.12) in the neighbour ostium. The rate of target lesion revascularisation was 2% with SES and 39% with BMS (p<0.001), and major adverse cardiac events (MACE) 6% versus 41% (p = 0.001).

CONCLUSIONS

In patients with ostial coronary lesions the angiographic outcome is improved and the long-term MACE rate is low after SES compared with BMS implantation.

Recurrent thrombotic RCA occlusions due to exaggerated stent protrusion into the aorta

We report a case with exaggerated stent protrusion from the right coronary ostium into the aorta leading to recurrent inferoposterior and right ventricular myocardial infarctions due to stent thrombosis, which were treated successfully with fibrinolysis. The stent was removed via transverse aortotomy and two bypass grafts were performed. Stents protruding from the aorta may not only cause technical difficulties but also carry a high risk of thrombosis.

Safety and feasibility of drug-eluting stent implantation at vertebral artery origin: the first case series in Asians

BACKGROUND/PURPOSE

Studies of the safety and efficacy of drug-eluting stent (DES) implantation to treat vertebral artery (VA) ostial stenosis are lacking in the Asian population. The aim of this study was to evaluate the feasibility and safety of DES implantation to treat VA ostial stenosis in Asians.

METHODS

We retrospectively analyzed the medical and radiologic records of patients receiving VA origin stenting with DES from October 2004 to September 2006 in the National Taiwan University Hospital.

RESULTS

Eleven symptomatic patients (9 male; mean age, 72 years) with 11 lesions treated with DES were included. There were eight lesions treated with paclitaxel-eluting stents and three lesions treated with sirolimus-eluting stents. The success rate for implantation of a DES was 100%. The percentage of stenosis was significantly reduced after stenting (86+/-5 to 2+/-4%; p<0.001). No peri-interventional neurologic, vascular, or other medical complications were noted. All patients were asymptomatic at the mean follow-up time of 18.7+/-8.6 months (range, 6-30 months). Two patients received repeat angiography at 4 or 8 months after stenting. No significant in-stent restenosis was found.

CONCLUSION

Symptomatic VA origin stenosis can be treated safely and effectively with DES in Asians.

Success rate of implantation and mid-term outcomes of the sirolimus-eluting stent

BACKGROUND

The sirolimus-eluting stent (SES) is currently the sole drug-coated stent approved for use in Japan, but there are few reports on its safety and outcomes in Japan.

METHODS AND RESULTS

From May 2004 to February 2005, a total of 297 patients with 402 lesions were treated with SES at 6 hospitals in the Kansai district. Follow-up angiography was performed in 82% of the patients and 80% of the lesions at 182+/-35 days after stenting. Coronary stenosis was evaluated using quantitative coronary angiography. Clinical and angiographic data were analyzed. Minimum lesion diameter was 0.75+/-0.52 mm and the reference diameter was 2.81+/-0.47 mm before stenting. The SES successfully dilated 99.5% of the lesions with few major adverse cardiac events. Restenosis occurred in 4.0% and the target lesion revascularization rate was 3.7%. Restenosis correlated with chronic hemodialysis, calcification, occlusion, ostial lesions, lesions kinked>45 degrees, right coronary artery (RCA) lesions and lesions at the ostium of the RCA.

CONCLUSION

SES demonstrated a high rate of successful implantation with few complications, and mid-term outcomes were excellent. Patients with lesions at the ostium of the RCA or under chronic hemodialysis developed restenosis.