185 Diagnostic accuracy of dynamic stress myocardial CT perfusion as compared with invasive coronary physiology metrics in stented patients: preliminary results of the advantage II study
Authors: Mushtaq Saima , Zanotto Lorenza , Conte Edoardo , Pontone Gianluca , Guglielmo Marco , Baggiano Andrea , Trabattoni Daniela , Gili Sebastiano , Galli Stefano , Troiano Sarah , Monizzi Giovanni , Melotti Eleonora , Lagrutta Ludovico , Randazzo Angelo , Bartorelli Antonio , Andreini Daniele 
Published: December 2021

Abstract

Aims
To compare the diagnostic performance of adenosine-stress dynamic myocardial perfusion assessed by CT (CTP) as compared with that of coronary CT angiography (CCTA) alone by using invasive fractional flow reserve (FFR) and index of microvascular resistance (IMR) as standard of reference. Diagnostic performance of CCTA for in-stent restenosis (ISR) detection is still challenging. Recently, CTP demonstrated additional specificity and diagnostic accuracy over CCTA alone in patients with previous stent implantation and suspected IRS or progression of coronary artery disease (CAD). However, no data are available in this clinical setting on the performance of CTP by using a new technique allowing for a non-invasive adjudication of regional myocardial blood flow (dynamic CTP) and to assess both macrovascular and microvascular disease status. Moreover, dynamic CTP was never compared vs. a comprehensive assessment of invasive coronary physiology (FFR and IMR).

Methods and results
We enrolled consecutive stable patients with previous coronary stenting referred for invasive coronary angiography (ICA) for clinical indication. All patients underwent dynamic stress myocardial CTP and rest CTP+CCTA by using a last generation scanner characterized by a 16-cm Z-axis coverage and fast (0.28 s) gantry rotation time. Invasive FFR and IMR were performed during ICA according to the standard practice. The diagnostic rate and diagnostic accuracy of CCTA and CTP were evaluated in a territory-based analyses vs. quantitative coronary angiography (QCA), FFR, and IMR. In 67 enrolled patients (55 men, mean age: 63.1 ± 8.2 years), the diagnostic rate (number of territories interpretable/number of territories evaluated) of CTP was significantly higher than that of CCTA (302/307 = 98.4% vs. 290/307 = 94.4%, P = 0.009). The interpretability of the combined CCTA/CTP approach was 99.7% (306/307 territories). When QCA was used as gold standard, CTP diagnostic accuracy was significantly higher than that of CCTA (84.4% vs. 80.1%, P = 0.01). When coronary physiology metrics were used as gold standard, CTP diagnostic accuracy was significantly higher than that of CCTA vs. both FFR (84.3% vs. 72.2%, P = 0.02) and IMR (83.3% vs. 70.2%, P = 0.02). The radiation exposure of CCTA+CTP was 8.7 ± 2.5 mSv.

Conclusions
In patients with coronary stents, dynamic CTP significantly improves diagnostic rate and accuracy of CCTA alone in comparison with both FFR and IMR. The non-invasive assessment of ISR is still challenging. The comprehensive assessment by cardiac CT provides anatomical combined to functional evaluation of coronary arteries in revascularized patients with good agreement with invasive physiological evaluation.