Classification of mechanisms of strut malapposition after angiographically optimized stent implantation: An optical coherence tomography study

The role of optical coherence tomography in guiding percutaneous coronary interventions: is left main the final challenge?

Left main (LM) coronary artery disease is a high-risk lesion subset, with important prognostic implications for the patients. Recent advances in the field of interventional cardiology have narrowed the gap between surgical and percutaneous approach of this complex lesion setting. However, the rate of repeat revascularization remains higher in the case of percutaneous coronary intervention (PCI) on long-term follow-up. As such, the need for better stent optimization strategies has led to the development of intravascular imaging techniques, represented mainly by intravascular ultrasound (IVUS) and optical coherence tomography (OCT). These techniques are both able to provide excellent pre- and post-PCI guidance. While IVUS is an established modality in optimizing LM PCI, and is recommended by international revascularization guidelines, data and experience on the use of OCT are still limited. This review paper deeply analyzes the current role of OCT imaging in the setting of LM disease, particularly focusing on its utility in assessing plaque morphology and distribution, vessel dimensions and proper stent sizing, analyzing mechanisms of stent failure such as malapposition and underexpansion, guiding bifurcation stenting, as well as offering a direct comparison with IVUS in this critical clinical scenario, based on the most recent available data.

Incidence, predictors, and clinical impact of the impeded-by-stent phenomenon after placing two-linked design new generation drug-eluting stents

BACKGROUND

When a catheter device is delivered during percutaneous coronary intervention, its passage can be disrupted by a deployed in a coronary artery. However, the condition and details of this phenomenon, that is impeded-by-stent phenomenon (ISP), remain unclear.

METHODS

We designed a prospective, open-label, single-center, observational study to clarify the incidence, predictors, and clinical impact of ISP in drug-eluting stents (DESs). Two independent operators observed and judged the occurrence of ISP, which was defined as all disturbances to a device delivery by deployed DESs. We consecutively used the Ultimaster™ (Terumo, Tokyo, Japan) DES for one month (109 patients, October 2018), followed by the Synergy™ (Boston Scientific Corporation, Marlborough, MA, USA) DES the next month (119 patients, November 2018).

RESULTS

DESs (2.5-4.0 mm in diameter) were implanted in 230 de novo coronary vessels. ISPs were observed in 17 of 239 stented segments (7.1 %). Multivariate analysis showed that bifurcation lesions (adjusted odds ratio [OR], 4.2; 95 % confidence interval [CI], 1.5-12.6; p = 0.008), predilatation balloon diameter (mm) (OR, 0.2; 95 % CI, 0.1-0.9; p = 0.03), and Ultimaster™ use (OR, 6.0; 95 % CI, 1.9-27.2; p = 0.002) were independent predictors of ISPs. During the 1.5-year follow-up period, no repeat revascularization or stent thrombosis occurred in patients with ISP.

CONCLUSIONS

ISP itself does not trigger notable clinical outcomes, including repeat revascularization and stent thrombosis. However, caution should be considered regarding the latent risk of procedural complications.

Intravascular imaging for left main stem assessment: An update on the most recent clinical data

Left main (LM) stem has different structural and anatomical characteristics compared to all of the other segments of the coronary tree, thus its management through percutaneous coronary intervention (PCI) is a challenge and is associated with worse clinical outcome and higher need for revascularization as compared to other lesion settings. Intravascular imaging, by means of intravascular ultrasound (IVUS) or optical coherence tomography (OCT), is an important tool for LM PCI guidance, aiming at improving the immediate performance and the long term outcome of this procedure. Following current guidelines and recent scientific findings, IVUS becomes important to firstly assess, and finally evaluate the result of LM stenting, according to the experience and preferences of the operator. The role of OCT still remains to be defined, but recent data is shedding light also on this imaging technique. The aim of this review is to highlight the latest scientific advancements regarding intravascular imaging in LM coronary artery disease.

Temporal changes of incomplete stent apposition during early phase after everolimus-eluting stent implantation: serial optical coherence tomography analyses at 2-week and 4-month

The healing process of acute incomplete stent apposition (ISA) in the early phase after stent implantation has not been well understood. We evaluated the temporal changes of ISA during the early phase after everolimus-eluting stent (EES) implantation using serial optical coherence tomography (OCT) analyses. Serial OCT examinations were performed immediately post-stenting and 2-week and 4-month after EES implantation for patients with ST-segment elevation myocardial infarction. At the most proximal cross-section of the implanted stent, the prevalence of ISA and maximum ISA distance were serially evaluated. In 45 patients with ST-segment elevation myocardial infarction, serial OCT analyses at 2-week and 4-month were performed. The prevalence of ISA gradually decreased over time, being 53.3% at baseline, 37.8% at 2-week follow-up, and 11.1% at 4-month follow-up (P < 0.001). The maximum ISA distance also decreased over time (P < 0.001). A receiver-operating curve analysis found that the optimal cut-off values of the baseline ISA distance for predicting persistent ISA at 2-week follow-up and 4-month follow-up were > 140 µm and > 215 µm, respectively. The baseline ISA distance was closely associated with the healing of ISA in the early phase after EES implantation. Maintaining the minimum ISA distance at post-stenting facilitates early phase healing of acute ISA.

Post-dilatation improves stent apposition in patients with ST-segment elevation myocardial infarction receiving primary percutaneous intervention: A multicenter, randomized controlled trial using optical coherence tomography

BACKGROUND

Stent failure is more likely in the lipid rich and thrombus laden culprit lesions underlying ST-segment elevation myocardial infarction (STEMI). This study assessed the effectiveness of post-dilatation in primary percutaneous coronary intervention (pPCI) for acute STEMI.

METHODS

The multi-center POST-STEMI trial enrolled 41 consecutive STEMI patients with symptom onset <12 hours undergoing manual thrombus aspiration and Promus Element stent implantation. Patients were randomly assigned to control group (n=20) or post-dilatation group (n=21) in which a non-compliant balloon was inflated to >16 atm pressure. Strut apposition and coverage were evaluated by optical coherence tomography (OCT) after intracoronary verapamil administration via thrombus aspiration catheter, post pPCI and at 7-month follow-up. The primary endpoint was rate of incomplete strut apposition (ISA) at 7 months after pPCI.

RESULTS

There were similar baseline characteristics except for stent length (21.9 [SD 6.5] mm vs. 26.0 [SD 5.8] mm, respectively, P=0.03). In post-dilatation vs. control group, ISA rate was lower (2.5% vs. 4.5%, P=0.04) immediately after pPCI without affecting final TIMI flow 3 rate (95.2% vs. 95.0%, P>0.05) or corrected TIMI frame counts (22.6±9.4 vs. 22.0±9.7, P>0.05); and at 7-month follow-up (0.7% vs. 1.8%, P<0.0001), the primary study endpoint, with similar strut coverage (98.5% vs. 98.4%, P=0.63) and 1-year rate of major adverse cardiovascular events (MACE).

CONCLUSION

In STEMI patients, post-dilatation after stent implantation and thrombus aspiration improved strut apposition up to 7 months without affecting coronary blood flow or 1-year MACE rate. Larger and longer term studies are warranted to further assess safety (ClinicalTrials.gov identifier: NCT02121223).