304 CORONARY COMPUTED TOMOGRAPHY ANGIOGRAPHY FOR THE ASSESSMENT OF SIROLIMUS-ELUTING RESORBABLE MAGNESIUM SCAFFOLD
Authors: Pompei Graziella , Tonet Elisabetta , Cossu Alberto , Caglioni Serena , Mele Daniela , Boccadoro Alberro , Micillo Marco , Cocco Marta , De Raffele Martina , Giganti Melchiorre , Biscaglia Simone , Sgura Fabio , Preti Gerlando , Quadri Giorgio , Cerrato Enrico , Campo Gianluca , Ruggiero Rossella 
Published: December 2022

Abstract

Background
Coronary computed tomography angiography (CCTA) is an established technique for non-invasive evaluation of the coronary arteries. Whereas artifacts limit the assessment of the stented vessels, studies supported its performance in vessels treated with first generation bioresorbable scaffold (BRS). Anatomical findings can be integrated with non-invasive fractional flow reserve (FFR-CT) to discriminate the presence or not of flow-limiting disease. After the failure of the first BRS generation, alternative platforms have been developed, including the second-generation resorbable magnesium scaffold (RMS). Ongoing studies investigate the long-term safety and effectiveness of RMS, but few evidence describes their performance with CCTA.

Aims
The present investigation aims to report the luminal measurement, FFR-CT assessment, and clinical outcomes, in the first patients treated with RMS in the Scaffold Implantation in Emilia-Romagna Plus Multi Absorbable Gears Intra Coronary (SHERPA-MAGIC) study.

Methods
As prespecified sub-study, patients underwent CCTA 18 months after RMS implantation. Three-dimensional models were reconstructed for simulation of coronary flow and pressure. FFR-CT analysis was performed using the DeepVessel FFR software (Keya Medical, Seattle, WA, USA).

Results
From December 2017 to July 2018, 34 patients underwent RMS implantation. After exclusion of 7 patients due to additional drug eluting stent (DES) implantation, poor CCTA quality and CCTA refusal, the population included 26 patients. Overall, 29 vessels were treated with 35 RMS. Median stent length was 25 [20-25] mm, with a median diameter of 3 [3-3.5] mm. Three-year follow-up was available for all patients. One patient received revascularization of the target vessel after 18-month CCTA. Another patient was admitted for atypical chest pain 12 months after index procedure. Quantitative analysis was feasible in all vessels (n=29). Complete RMS reabsorption was observed in 27 cases. Median minimal lumen diameter (MLD) and area (MLA) of the scaffolded segments were 2.5 [2.1-2.8] mm and 6.4 [4.4-8.4] mm2, respectively. Non-invasive FFR analysis was feasible in 23 vessels (80%). The causes for missing computation were artifacts and the incomplete documentation of the entire coronary artery. Median FFR-CT in the target vessels was 0.88 [0.81-0.91]. Ttwo target vessels showed a flow-limiting FFR-CT value. In the first case, the patient underwent coronary artery angiography. Invasive FFR confirmed a flow-limiting stenosis (FFR value 0.74), and a new PCI was performed. In the second case, the patient was asymptomatic in optimal medical therapy, and mid-distal LAD was involved (FFR-CT value 0.79).

Conclusions
In a highly selected population of patients undergoing RMS implantation with a standardized technique, CCTA is feasible and allows to discriminate long-term anatomical and functional performance of scaffolded segments.