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

Risk of Dislodgement of Ultrathin Drug Eluting Stents Versus Thick Drug Eluting Stents

Modern ultrathin struts drug eluting stents (DES), due to their constructive characteristics, might be more prone to stent dislodgment than the old thick DES. Our study is aimed to retrospectively analyze and compare the incidence and outcomes of stents dislodgment in thick (TSS) and ultrathin strut stents (USS).We retrospectively analyzed the procedural and medical data of 8,564 consecutive patients (mean age 64.3 ± 11.2 years old, 4442 males) who underwent percutaneous coronary intervention with DES implantation in our Institution between 1st January 2005 to 1st January 2020. Overall, 25,692 (mean of 3.2 stent for patients) have been implanted over the study period (10648 TSS and 15044 and USS, respectively). Stent dislodgment globally occurred in 0.56% of the implanted stents (0.28% vs 0.78%, p <0.001 for TTS and USS, respectively). Coronary artery calcifications, ostial lesion, coronary artery tortuosity, and a lesion length >25 mm were independent predictors of type I and II USS dislodgments. At 12 months follow up, the rate of target lesion failure was higher in the TTS group (30.7 vs 12.7 %, p <0.001). Stent dislodgement is unusual in the modern era but is more frequent using USS than TTS DES.

Prolonged Balloon Inflation to Effect Full Stent Expansion in Critical CAD During Left Ventricular Support

The extent to which a stent is expanded is a primary factor in determining both short- and long-term outcomes during percutaneous coronary intervention (PCI). This paper presents the first case of prolonged balloon inflation using the pressure optimization protocol allowing full stent expansion during PCI of critical coronary artery disease with severely reduced ejection fraction using the Impella. (Level of Difficulty: Intermediate.)

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.

Stent "Hygiene"

Studies demonstrate ideal Stent expansion with prolonged inflations. Longer inflations, a mediator of greater stent expansion, lower immediate, subacute, and late stent failure. Research should focus on components of stent deployment that optimize early and late stent outcomes.