Performance of a diagnostic algorithm based on cardiac computed tomography angiography and dynamic perfusion in intermediate-high pretest risk of coronary artery disease or chronic coronary syndrome
Authors: Francesc Altadill Balsells F , Carlos Gonzalez Freixa C , Lidia Bos Real L , Mario Salido Iniesta M , Juan Fernandez Martinez J , Irene Menduina Gallego I , Chi Hion Li C , Sandra Pujadas Olano S , Martin Descalzo Buey M , Ruben Leta Petracca R , David Vilades Medel D 
Published: June 2024

Abstract

Introduction
Multidetector computed tomography (MDCT) has become essential in the diagnostic process for symptomatic patients with suspected coronary artery disease (CAD) or history of chronic coronary syndrome (CCS). Dynamic myocardial perfusion computed tomography (DynCTP) stands out as an innovative technique that adds complementary functional information to anatomical studies, integrating thediagnostic process into a single non-invasive imaging technique.

Purpose
To assess the clinical performance of a diagnostic algorithm based on MDCT and DynCTP in symptomatic patients with suspected CAD or a history of CCS and compare it with the previous MDCT-only algorithm.

Methods
We conducted a single-center observational study with two cohorts of symptomatic patients with suspected CAD or known CCS. The first cohort underwent a MDCT-only algorithm from January 2017 to January 2019 using a 128-slice CT scanner and the second cohort a diagnostic algorithm based on MDCT and DynCTP from April 2021 to May 2023 with a 192-slice dual source CT. DynCTP was conducted if CAD-RADS score ≥3 or nonconclusive coronary segments were identified. Cohorts were matched by gender, cardiovascular risk factors prevalence, and atherosclerotic burden determined by CAD-RADS score. After the same follow-up period, we analyzed the number of requested functional tests (cardiac magnetic resonance or ergometry) and cardiac catheterizations, as well as a composite of major cardiovascular events: cardiovascular mortality, acute coronary syndrome, and the need for revascularization.

Results
204 patients were included (102 in each cohort) with a mean follow-up time of 22 ± 7 months. Table 1 summarizes their baseline characteristics. The patients in the second cohord received less radiation (412 ± 269mGy vs. 676 ± 522mGy; p&lt;0.01) but more contrast volume (93.7 ± 24.4mL vs. 75.9 ± 15.4mL; p&lt;0.01) than those of the first cohort.
In the MDCT and DynCTP cohort, additional functional tests after MDCT decreased by 59% (17.6% vs. 43.1% of patients; p&lt;0.01), and the time to a clinical decision on therapeutic strategy was shortened by 42% (102 vs. 60 days; p&lt;0.01). Additionally, the number of requested cardiac catheterizations without prior functional information decreased by 86.3% (9% vs. 64%, p&lt;0.01).
There were no significant differences in the number of cardiac catheterizations performed (27% vs. 33%; p=0.36) or major cardiovascular events (24% vs. 28%; p =0.43) between cohorts.

Conclusions
In our center, implementing a MDCT and DynCTP diagnostic algorithm in symptomatic patients with suspected CAD or known CCS significantly shortened the diagnostic process and number of additional tests. This approach also increased the percentage of patients referred to invasive catheterization with prior functional information. No differences were observed between the two study periods in terms of the number of catheterizations and major cardiovascular adverse events.Baseline characteristics of patients Differences between two periods