Magnetic Resonance Imaging in the Prognostic Evaluation of Patients with Pulmonary Arterial Hypertension

Abstract

Rationale: Prognostication is important when counseling patients and defining treatment strategies in pulmonary arterial hypertension (PAH).

Objectives: To determine the value of magnetic resonance imaging (MRI) metrics for prediction of mortality in PAH.

Methods: Consecutive patients with PAH undergoing MRI were identified from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Centre) pulmonary hypertension registry.

Measurements and main results: During the follow-up period of 42 (range, 17-142) months 576 patients were studied and 221 (38%) died. A derivation cohort (n = 288; 115 deaths) and validation cohort (n = 288; 106 deaths) were identified. We used multivariate Cox regression and found two independent MRI predictors of death (P < 0.01): right ventricular end-systolic volume index adjusted for age and sex, and the relative area change of the pulmonary artery. A model of MRI and clinical data constructed from the derivation cohort predicted mortality in the validation cohort at 1 year (sensitivity, 70 [95% confidence interval (CI), 53-83]; specificity, 62 [95% CI, 62-68]; positive predictive value [PPV], 24 [95% CI, 16-32]; negative predictive value [NPV], 92 [95% CI, 87-96]) and at 3 years (sensitivity, 77 [95% CI, 67-85]; specificity, 73 [95% CI, 66-85]; PPV, 56 [95% CI, 47-65]; and NPV, 87 [95% CI, 81-92]). The model was more accurate in patients with idiopathic PAH at 3 years (sensitivity, 89 [95% CI, 65-84]; specificity, 76 [95% CI, 65-84]; PPV, 60 [95% CI, 46-74]; and NPV, 94 [95% CI, 85-98]).

Conclusions: MRI measurements reflecting right ventricular structure and stiffness of the proximal pulmonary vasculature are independent predictors of outcome in PAH. In combination with clinical data MRI has moderate prognostic accuracy in the evaluation of patients with PAH.

Keywords: magnetic resonance imaging; prognosis; prognostic models; pulmonary arterial hypertension.

Figure 1.

Images detailing pulmonary artery (PA) size and relative area change analysis. Maximal PA area (A) and minimal PA area (B), and right ventricular volume and mass calculation from end-diastolic images (C) and end-systolic images (D). MR = magnetic resonance; RV = right ventricle.

Figure 2.

Study flow diagram. CHD = congenital heart disease; CTD = connective tissue disease; IPAH = idiopathic pulmonary arterial hypertension; MRI = magnetic resonance imaging; PAH = pulmonary arterial hypertension.

Figure 3.

Kaplan-Meier survival curves showing the outcome of right ventricular end-systolic volume % predicted (left) and pulmonary artery (PA) relative area change (right). Numbers at risk are presented below each plot. MRI = magnetic resonance imaging; RVESVI = right ventricular end-systolic volume index.

Figure 4.

Receiver operating curves showing important predictors of mortality in all patients with pulmonary arterial hypertension in the derivation cohort (top left) and validation cohort (top right), and patients with idiopathic pulmonary arterial hypertension in the derivation cohort (bottom left) and validation cohort (bottom right). AUC = area under the curve; IPAH = idiopathic pulmonary arterial hypertension; MRI = magnetic resonance imaging; RVESVI = right ventricular end-systolic volume index.