Identification of Cardiac Magnetic Resonance Imaging Thresholds for Risk Stratification in Pulmonary Arterial Hypertension

Abstract

Rationale: Pulmonary arterial hypertension (PAH) is a life-shortening condition. The European Society of Cardiology and European Respiratory Society and the REVEAL (North American Registry to Evaluate Early and Long-Term PAH Disease Management) risk score calculator (REVEAL 2.0) identify thresholds to predict 1-year mortality. Objectives: This study evaluates whether cardiac magnetic resonance imaging (MRI) thresholds can be identified and used to aid risk stratification and facilitate decision-making. Methods: Consecutive patients with PAH ( n = 438) undergoing cardiac MRI were identified from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Center) MRI database. Thresholds were identified from a discovery cohort and evaluated in a test cohort. Measurements and Main Results: A percentage-predicted right ventricular end-systolic volume index threshold of 227% or a left ventricular end-diastolic volume index of 58 ml/m 2 identified patients at low (<5%) and high (>10%) risk of 1-year mortality. These metrics respectively identified 63% and 34% of patients as low risk. Right ventricular ejection fraction >54%, 37–54%, and <37% identified 21%, 43%, and 36% of patients at low, intermediate, and high risk, respectively, of 1-year mortality. At follow-up cardiac MRI, patients who improved to or were maintained in a low-risk group had a 1-year mortality <5%. Percentage-predicted right ventricular end-systolic volume index independently predicted outcome and, when used in conjunction with the REVEAL 2.0 risk score calculator or a modified French Pulmonary Hypertension Registry approach, improved risk stratification for 1-year mortality. Conclusions: Cardiac MRI can be used to risk stratify patients with PAH using a threshold approach. Percentage-predicted right ventricular end-systolic volume index can identify a high percentage of patients at low-risk of 1-year mortality and, when used in conjunction with current risk stratification approaches, can improve risk stratification. This study supports further evaluation of cardiac MRI in risk stratification in PAH.

Cardiac Magnetic Resonance Imaging in Pulmonary Arterial Hypertension: Ready for Clinical Practice and Guidelines?

“…1(C) ) and reduced LV volume, RV ejection fraction (RVEF), and stroke volume (SV) are noted to be prognostic markers for PAH [ 14 ]. When used in conjunction with existing risk assessment tools, these CMR markers show increased value over current prognostic methods for risk classification [ 15 , 16 ••]. After adjusting for age, sex, and body surface area, 11% could be reclassified as having a higher risk and 36% a lower risk of 1-year mortality [ 16 ••].…”

BNP/NT-proBNP in pulmonary arterial hypertension: time for point-of-care testing?

“…An update, REVEAL 2.0, has recently been published [9] which, in an independent cohort, demonstrated 1-year mortality estimates of 2.6%, 8.6% and 25.4% for low-, intermediate-and high-risk groups respectively, with 5-year estimates of 16.1%, 41.5% and 88.0%, respectively [41]. Additionally, a study using CMR of RV end systolic volume index adjusted for age and sex has been shown to further improve risk stratification for 1-year mortality when used with either the REVEAL 2.0 score or a modified French Pulmonary Hypertension Risk score [13].…”

“…For assessment of RV function, cardiac magnetic resonance (CMR) imaging is the gold standard [11][12][13], but cost, availability and until recently the paucity of data on its value in risk stratification [13] have limited its use. Active B-type natriuretic peptide (BNP; or brain natriuretic peptide) and the functionally inert N-terminal prohormone of BNP (NT-proBNP) are well-established clinical biomarkers used in PAH and other cardiovascular disorders, such as acute/chronic heart failure and are used as surrogate markers of cardiac function [1,14,15].…”

Identification of Cardiac MRI and Bio-Marker Thresholds for One-Year Survival in Pre-Capillary Pulmonary Hypertension: Prospective Study

“…RV dysfunction is related to the severity of PAH and clinical status of the patient [19]. Lewis and colleagues recently evaluated and validated right-ventricular CMR parameters for risk stratification in PAH [20]. In this study, patients were divided into low, intermediate, and high risk according one-year mortality, and RV EF was as follows: >54%, 37%-54%, and <37%.…”