Comparison of exercise testing and CMR measured myocardial perfusion reserve for predicting outcome in asymptomatic aortic stenosis: the PRognostic Importance of MIcrovascular Dysfunction in Aortic Stenosis (PRIMID AS) Study

Abstract

Aims: To assess cardiovascular magnetic resonance (CMR) measured myocardial perfusion reserve (MPR) and exercise testing in asymptomatic patients with moderate-severe AS.

Methods and results: Multi-centre, prospective, observational study, with blinded analysis of CMR data. Patients underwent adenosine stress CMR, symptom-limited exercise testing (ETT) and echocardiography and were followed up for 12-30 months. The primary outcome was a composite of: typical AS symptoms necessitating referral for AVR, cardiovascular death and major adverse cardiovascular events. 174 patients were recruited: mean age 66.2 ± 13.34 years, 76% male, peak velocity 3.86 ± 0.56 m/s and aortic valve area index 0.57 ± 0.14 cm2/m2. A primary outcome occurred in 47 (27%) patients over a median follow-up of 374 (IQR 351-498) days. The mean MPR in those with and without a primary outcome was 2.06 ± 0.65 and 2.34 ± 0.70 (P = 0.022), while the incidence of a symptom-limited ETT was 45.7% and 27.0% (P = 0.020), respectively. MPR showed moderate association with outcome area under curve (AUC) = 0.61 (0.52-0.71, P = 0.020), as did exercise testing (AUC = 0.59 (0.51-0.68, P = 0.027), with no significant difference between the two.

Conclusions: MPR was associated with symptom-onset in initially asymptomatic patients with AS, but with moderate accuracy and was not superior to symptom-limited exercise testing. ClinicalTrials.gov (NCT01658345).

Keywords: Aortic stenosis; Exercise testing; Magnetic resonance imaging; Myocardial perfusion reserve.

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Figures

Figure 1

Recruitment flowchart.

Figure 2

ROC curves for MPR and symptom-limited ETT (A) conventional definition, (B) strict definition, for predicting the primary outcome.

Figure 3

Kaplan-Meier curves for event-free survival for those (A) above and below MPR cut-point of 2.098, (B) symptom-limited ETT (conventional definition) and (C) symptom-limited ETT (strict definition).