Comparison between Three-Dimensional Angiographic Reconstruction and Intravascular Ultrasound Imaging for the Measurement of Cross-Sectional Luminal Dimensions in Intermediate Coronary Lesions

Safety of intermediate left main stenosis revascularization deferral based on fractional flow reserve and intravascular ultrasound: A systematic review and meta-regression including 908 deferred left main stenosis from 12 studies

BACKGROUND

Current guidelines recommend intravascular ultrasound (IVUS) or fractional flow reserve (FFR) to decide upon ambiguous left main (LM) disease. However, no study has compared the safety of LM revascularization deferral based on FFR or IVUS.

METHODS

MEDLINE/PubMed was systematically screened for studies reporting on deferred treatment of angiographically ambiguous LM based upon FFR or IVUS evaluation. Baseline, angiographic and outcome data were appraised and pooled separately for each strategy according to random-effect models with inverse-variance weighting.

RESULTS

A total of 908 LM stenoses from 7 FFR and 5 IVUS studies were included with median follow-up of 29.0 and 31.5 months respectively. Per year of follow-up occurrence of overall MACE were 5.1% in FFR group and 6.4% in IVUS group while death, myocardial infarction, LM revascularization were respectively 2.6%, 1.5% and 1.8% vs. 3.0%, 0.5% and 2.2%. Meta-regression analysis suggested the influence of a distal LM stenosis on MACE in FFR group (β = 0.06, p = 0.01) and age in IVUS group (β = 0.4, p = 0.001). In individual studies several independent predictors of MACE were identified including use of lower doses of intracoronary adenosine (OR 1.39, p = 0.04) in FFR group and plaque burden (OR 1.34, p = 0.025), number of other diseased vessels (OR 1.39, p = 0.04) and any untreated stenosis (OR 3.80; p = 0.037) in IVUS- studies.

CONCLUSIONS

Deferring LM intermediate stenosis on the basis of FFR or IVUS showed an acceptable and similar risk of events in a mid-term follow-up. Conversely, several different variables related to each technique showed an interaction on outcome.

Prospective randomized comparison of sirolimus- or everolimus-eluting stent to treat bifurcated lesions by provisional approach

OBJECTIVES

This study sought to compare the procedural performance and the acute angiographic result on side-branch ostium obtained using 2 different drug-eluting stents (DES) to treat patients with bifurcated coronary lesions.

BACKGROUND

Drug-eluting stents are routinely used in percutaneous coronary interventions (PCI) of bifurcated coronary lesions. Different DES types have major technical differences that may influence the procedural and clinical performance in bifurcation PCI.

METHODS

Consecutive patients with bifurcated lesions undergoing DES implantation using a systematic provisional-stenting strategy were randomized to sirolimus-eluting stent (SES) or everolimus-eluting stent (EES) before intervention. The procedural details for PCI were prospectively recorded to assess the occurrence of any trouble in the side-branch (SB) management (primary end point). Post-PCI angiographic result (primary end point: minimal lumen diameter at SB ostium) was evaluated offline by 3-dimensional reconstruction and quantitative coronary analysis. Clinical outcome was prospectively recorded up to 18 months to assess the occurrence of target bifurcation failure.

RESULTS

A total of 150 patients were enrolled in the study (29% diabetics, 17% unprotected left main). The stent was successfully implanted according to randomization in all cases. Procedural performance was not significantly different between the 2 kinds of DES. Three-dimensional reconstruction and quantitative coronary analysis showed similar post-PCI results in the main vessel and better results in the SB with EES than with SES (minimal lumen diameter at SB ostium: 1.94 ± 0.72 mm vs. 1.64 ± 0.62 mm; p = 0.013). At 18 months, target bifurcation failure occurred in 7 (9.0%) of SES-treated patients versus 8 (10.7%) of EES patients (p = 0.57).

CONCLUSIONS

In patients with bifurcated lesions treated by provisional stenting technique, EES compared with SES is associated with similar procedural performance and better 3-dimensional reconstruction and quantitative coronary analysis result in the SB. Both DES are associated with low rates of major adverse events and angiographic failure. (Sirolimus Versus Everolimus-Eluting Stent Randomized Assessment in Bifurcated Lesions and Clinical Significance of Residual Side-Branch Stenosis [SEA-SIDE]; NCT00697372).

Flow simulation studies in coronary arteries--impact of side-branches

AIMS

Wall shear stress (WSS) may induce local remodeling of the vascular wall and the WSS pattern in turn depends on vascular geometry. We aimed to elucidate the impact of side-branches on local WSS.

METHODS AND RESULTS

Steady numerical flow simulation studies were performed in three-dimensional reconstructed right coronary artery (RCA) trees. RCA from seven controls, five patients with coronary artery disease (CAD) and five patients with aneurysmatic CAD (AnCAD) classified by expert visual diagnosis were studied. Then three transient flow simulations were performed with cases representative for each group in order to evaluate the impact of pulsatile flow simulation. As vascular size and flow rates vary considerably between patients, non-dimensional approaches were applied for group comparison. A point-to-point comparison of the WSS in the same tree with and without side-branches revealed local differences in WSS of up to 12.0 Pa. This was caused by a reduction of volume flow of up to 78.7% in the trunk. Differences are not only limited to bifurcation sites but also affect local narrowings and strongly curved segments. The point-to-point comparison of steady and transient simulations found an average increase of WSS of below 7% in transient simulations. No significant differences were found between histograms of pulsatile and steady simulations, showing a high cross-correlation of >0.97.

CONCLUSION

Side-branches must not be neglected in numerical flow simulation (steady and transient) studies. Steady simulations are valid for an assessment of time-averaged WSS distributions.

Real-time 3D imaging in the cardiac catheterization laboratory

Worldwide experience in coronary catheterization and angiography for the detection and evaluation of lumen narrowing is extensive. Conventional coronary angiography analysis is complex since these arteries are of relatively small caliber and in constant movement, while being synchronized with the movement of the heart chambers and respiratory system. Moreover, atherosclerotic plaques in the coronary tree are themselves very intricate and frequently positioned in eccentric locations. The last decade has witnessed significant advances as novel data acquisition and processing techniques have been introduced. Researchers have developed novel processing systems that make it possible to construct 3D images in real-time during coronary intervention. The most common solutions are rotational imaging and reconstruction from multiple single-plane images. These techniques produce real-time 3D images of the coronary arteries in the catheterization laboratory. This article describes these state-of-the-art imaging methods and other specific novel applications in clinical practice, such as stent enhancement, guidance during transcatheter aortic valve implantation and advanced geometrical analysis with computational fluid dynamics.