Better Inflation Time of Stent Balloon for Second-Generation Drug-Eluting Stent Expansion and Apposition: An Optical Coherence Tomography Study

Percutaneous coronary intervention for bifurcation coronary lesions using optimised angiographic guidance: the 18th consensus document from the European Bifurcation Club

The 2023 European Bifurcation Club (EBC) meeting took place in Warsaw in October, and the latest evidence for the use of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) to optimise percutaneous coronary interventions (PCI) on coronary bifurcation lesions (CBLs) was a major focus. The topic generated deep discussions and general appraisal on the potential benefits of IVUS and OCT in PCI procedures. Nevertheless, despite an increasing recognition of IVUS and OCT capabilities and their recognised central role for guidance in complex CBL and left main PCI, it is expected that angiography will continue to be the primary guidance modality for CBL PCI, principally due to educational and economic barriers. Mindful of the restricted access/adoption of intracoronary imaging for CBL PCI, the EBC board decided to review and describe a series of tips and tricks which can help to optimise angiography-guided PCI for CBLs. The identified key points for achieving an optimal angiography-guided PCI include a thorough analysis of pre-PCI images (computed tomography angiography, multiple angiographic views, quantitative coronary angiography vessel estimation), a systematic application of the technical steps suggested for a given selected technique, an intraprocedural or post-PCI use of stent enhancement and a low threshold for bailout use of intravascular imaging.

A randomized controlled clinical trial of prolonged balloon inflation during stent deployment strategy in primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: a pilot study

Background

Primary percutaneous coronary intervention (PPCI) is the standard procedure for reperfusion for ST-segment elevation myocardial infarction (STEMI), but the occurrence of the no-reflow phenomenon remains common and is associated with adverse outcomes.

Aims

This study aimed to evaluate whether prolonged balloon inflation in stent deployment would lessen the occurrence of the no-reflow phenomenon in PPCI compared with conventional rapid inflation/deflation strategy.

Methods

Patients were randomly assigned to either the prolonged balloon inflation in stent deployment group (PBSG) or conventional deployment strategy group (CDSG) in a 1:1 ratio. A subset of patients was included in the cardiac magnetic resonance (CMR) assessment.

Results

Thrombolysis in MI (TIMI) flow grade 3 was found in 96.7% and 63.3% of the patients of the PBSG and CDSG, respectively (P = 0.005). The results of the PBSG and CDSG are respectively shown as follows: 0% versus 30% no-reflow or slow flow (P = 0.002); 90% versus 66.7% ST-segment resolution ≥ 50% (P = 0.028); 35.6 ± 14.5 frames versus 49.18 ± 25.2 frames on corrected TIMI frame count (P = 0.014); and 60% versus 20% myocardial blush grade 3 (P = 0.001). At 1 month, the major cardiovascular adverse event (cardiovascular mortality) rate was 3.3% in both groups; at 1 year, the rate was 3.3% and 6.7% for the PBSG and CDSG, respectively (P = 1.00). In the CMR subset of cases, the presence of microvascular obstruction (MVO) was detected in 6.7% and 50% of the patients in the PBSG and CDSG, respectively (P = 0.023).

Conclusion

In our pilot trial, prolonged balloon inflation during stent deployment strategy in PPCI reduces the occurrence of the no-reflow phenomenon in patients with STEMI and improved the myocardial microcirculation perfusion (ClinicalTrials.gov number: NCT03199014; registered: 26/June/2017).

Impact of the Balloon Inflation Time and Pattern on the Coronary Stent Expansion

Objectives

To assess the expansion pattern of coronary stents by using different balloon inflation times and pressures.

Background

The selection of coronary stent size and its proper deployment is crucial in coronary artery interventions, having an impact on the success of the procedure and further therapy.

Methods

Ten pairs of different stents were deployed under nominal pressure using sequential (5, 5, 10, and 10 seconds of repeated inflations, thus 30 seconds of summarized time) and continuous (30 seconds) deployment pattern. After each given time-point, intraluminal stent measurements were performed by optical coherence tomography (OCT) and intravascular ultrasound (IVUS).

Results

Both in-stent diameters and cross-section areas (CSA) of paired stents measured by OCT at all sequential time-points were significantly smaller compared to given manufacturers charts' values (90% to 94% for diameters and 81% to 88% for CSA, p<0.05). Significant increase of in-stent diameter and CSA was observed across the step-by-step deployment pattern. In-stent lumen measurements were significantly larger when sequential deployment pattern was applied compared to continuous deployment. Additional measurements were also done for overlapping segments of stents, showing smaller in-stent measurements of the latter compared to nonoverlapping segments. Validation of OCT and IVUS measurements using a phantom metallic tube showed perfect reproducibility with OCT and overestimation with IVUS (8% for diameters and 16% for CSA).

Conclusions

Stent diameter after deployment is time-dependent and not only pressure-dependent. Different stent expansion behavior, depending on the applied deployment pattern (sequential and nonsequential), was observed.

Prospective randomized trial of paclitaxel-coated balloon versus bare-metal stent in high bleeding risk patients with de novo coronary artery lesions

BACKGROUND

In patients with high bleeding risk, percutaneous coronary intervention is still debated. This study compared 9-month angiographic and physiologic results in patients with high bleeding risk and de novo coronary lesions treated with either paclitaxel-coated balloon (PCB) or bare-metal stent (BMS).

PATIENTS AND METHODS

A total of 40 patients (40 lesions) with high bleeding risk who underwent successful balloon angioplasty with fractional flow reserve (FFR) after balloon angioplasty more than 0.80 were randomized 1: 1 to treatment with PCB versus BMS. Dual antiplatelet therapy was limited to 1 month after the procedure.

RESULTS

Baseline clinical and lesional characteristics were well balanced between the two groups. There was no significant difference in the postprocedural FFR (0.87 ± 0.06 in PCB vs. 0.89 ± 0.06 in BMS, P = 0.254). At 9 months, late luminal loss was significantly lower in the PCB group (0.2 ± 0.3 vs. 1.2 ± 0.8 mm, P < 0.001). Restenosis only occurred in the BMS group (0 vs. 25.0%, P = 0.049).

CONCLUSION

In patients with high bleeding risk, FFR-guided PCB treatment showed superior efficacy in terms of angiographic and physiologic patency compared with BMS at mid-term follow-up with only 1 month of dual antiplatelet therapy (Clinicaltrials.gov identifier, NCT02456402).

Improved stent expansion with prolonged compared with short balloon inflation: A meta-analysis

BACKGROUND

Despite evidence from individual studies suggesting that prolonged inflation improves coronary stent expansion, relatively shorter inflation times are commonly employed in clinical practice.

METHODS

We performed an electronic search of PubMed, Web of Science, Cochrane, and CINAHL databases to retrieve outcome studies comparing prolonged versus short inflation times during stent deployment. Outcomes studied included minimal stent diameter (MSD) and minimal stent area (MSA). Standardized mean difference (SMD) was used to estimate the effect sizes for these continuous variables.

RESULTS

Seven studies with a total of 341 patients (415 lesions; mean age 67.6 years; 82% male) were included. Drug-eluting stents were used in 89 ± 15% of coronary lesions. Prolonged stent inflation was associated with increased minimal stent diameter (2.93 ± 0.34 mm vs. 2.72 ± 0.28 mm; SMD = 0.42; 95% CI 0.25-0.59; P < 0.001) and minimal stent area (5.99 ± 1.21 mm² vs. 5.17 ± 0.87 mm² ; SMD = 0.46; 95% CI 0.19-0.73; P = 0.001) compared with shorter duration stent inflation. This difference remained significant in sensitivity analyses that excluded studies with very prolonged inflation duration or multiple stent balloon inflations.

CONCLUSION

Despite differences in duration and methodology, prolonged stent inflation is associated with improved expansion compared with shorter duration. The effect of this optimization recommends randomized trials to determine whether long-term outcomes can be improved by this simple technical modification.

Optical coherence tomography-verified longer balloon inflation time may provide better stent apposition and optimal index parameters

BACKGROUND

Incomplete stent expansion and inadequate apposition predispose to stent thrombosis following percutaneous coronary intervention. Recent studies have shown that increasing the duration of balloon inflation during stent employment was beneficial. Thus, the balloon inflation time required for optimal stent expansion and apposition in patients receiving second-generation drug-eluting stents (DES) were determined using optical coherence tomography (OCT).

PATIENTS AND METHODS

Between April 2014 and March 2015, 38 patients (28 men, 10 women; mean age 60.5 ± 11.4 years) with stable angina pectoris due to single significant de novo coronary artery stenosis were prospectively enrolled. All patients were administered aspirin and clopidogrel and received weight-adjusted intravenous unfractionated heparin. Images of basal lesions were obtained using the C7XR LightLab Dragonfly OCT catheter.

RESULTS

Expansion and apposition parameters improved with increasing duration of balloon inflation (30 s or 60 s) with nominal pressure (12 atm). Mean lesion length was 19.8 ± 7.6 mm. Mean stent diameter and length were 2.8 ± 0.36 mm and 24.9 ± 7.6 mm, respectively.

CONCLUSION

With deployment of a stent at nominal pressure with conventional duration, inadequate stent expansion and malapposition frequently occurred as detected by OCT; however, a balloon inflation duration of 60 s markedly improved stent expansion and apposition parameters without significant complications.