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Abstract
Right ventricular (RV) function is known to predict survival in pulmonary hypertension (PH). Furthermore, increasing right ventricular volumes (RVEDVI, RV end diastolic volume and RVESVI, RV end systolic volume index) and falling ejection fraction (RVEF) whilst on treatment have been shown to determine poorer outcome.1 Measurement of RV function by cardiac MRI (CMR) is not widely available and often poorly tolerated in very breathless patients. Monitoring of PH patients traditionally focuses on serial 6 min walk testing (6MWD) and N terminal pro brain natriuretic peptide (NTproBNP), a biomarker that has been shown to reflect RV function and structure.2 We hypothesised that ∆NTproBNP is a superior non invasive marker of ∆RV function than ∆6MWD, and predicts survival.
Methods 59 patients with precapillary PH whom underwent serial CMR between 2004 and 2014 with 6MWD and/or NTproBNP sampling within 1 month of scan were retrospectively included. 146 ∆RV function values were calculated. For survival analysis, patients were censored at last day of study (24/6/14) or if lost to follow up. Survival was taken from the date of the second CMR scan. Due to the interaction between cardiac MRI values, only univariate survival analysis was performed.
Results ∆NTproBNP correlates more closely with ∆RVEF, ∆RVEDVI, ∆RVESVI than 6MWD (table1). Both ∆NTproBNP and ∆6MWD predicted survival [HR 1.001 95% CI 1.001–1.002 p
Conclusion ∆NTproBNP is superior to ∆6MWD as a surrogate marker of changing RV function which can be easily evaluated in the clinic setting. Both ∆NTproBNP and ∆ 6MWD predict survival in PH.
References
van Wolferen SA, Marcus JT, Boonstra A, Marques KMJ, Bronzwaer JGF, Spreeuwenberg MD, et al. Prognostic value of right ventricular mass, volume, and function in idiopathic pulmonary arterial hypertension. European Heart Journal. 2007;28(10):1250–7
Blyth KG, Groenning BA, Mark PB, Martin TN, Foster JE, Steedman T, et al. NT-proBNP can be used to detect right ventricular systolic dysfunction in pulmonary hypertension. European Respiratory Journal. 2007;29(4):737–44
Pearson correlations for ∆NTproBNP and ∆6MWD with indices of ∆RV function. Abbreviations; right ventricular ejection fraction RVEF; right ventricular end diastolic volume index RVEDVI; right ventricular end systolic volume index RVESVI; stroke volume index SVI