P2442Myocardial performance index predicts mortality in people with obstructive lung function from the general population
Authors: Andersen D , Moegelvang R , Schnohr P , Lange P , Modin D , Alhakak A S , Jensen M T , Sivapalan P , Jensen J U S , Gislason G , Biering-Soerensen T 
Published: October 2019

Abstract

Background
Forced expiratory volume in one second (FEV1) is a significant predictor of mortality in patients with obstructive lung function (OL). Whether echocardiography can be used to identify patients at high risk, and whether it provides incremental prognostic information on mortality in patients with OL, remains unknown.

Methods
In a large, low-risk general population study, 1873 participants underwent a health examination with spirometry and echocardiography, including tissue Doppler imaging (TDI). The myocardial performance index (MPI) was calculated as the sum of the isovolumic contraction time (IVCT) and the isovolumic relaxation time (IVRT) divided by the left ventricle ejection time (LVET). Spirometry included measurements of (FEV1) and the forced vital capacity (FVC). OL was defined as FEV1/FVC <0.70. The primary endpoint was all-cause mortality.

Results
The mean age was 59±16 years, 57% were women, 43% had hypertension, 11% had diabetes, and 6% had ischemic heart disease. Of the 1873 included participants, 288 (15%) were classified as having OL at baseline. During follow up (median 13.7 years (IQR 13.2–16.2)), 584 (31%) persons died, hereof 178 (62%) in the subgroup of participants with OL and 406 (26%) in the subgroup of participants with normal lung function.
OL was associated with presence of left ventricular hypertrophy (higher left ventricular mass index), impaired diastolic function (lower E, higher A, lower E/A ratio, longer deceleration time, lower e' and higher E/e'), lower global longitudinal strain, and higher MPI.
In unadjusted analysis, higher MPI was associated with all-cause mortality for participants with OL (HR=1.18 (1.11–1.26), p<0.001, per 0.1 increase) and for participants with normal lung function (HR=1.42 (1.34–1.50), p<0.001, per 0.1 increase). The predictive value of MPI was significantly modified by the presence of obstructive lung function (p<0.001).
After multivariable adjustment for age, sex, FEV1/FVC, heart rate, systolic blood pressure, smoking status, body mass index (BMI), hypertension, diabetes, ischemic heart disease, ischemic stroke and heart failure at baseline, MPI remained an independent predictor of all-cause mortality (HR=1.19 (1.06–1.34), p=0.004, per 0.1 increase) for participants with OL but not for participants with normal lung function (HR=1.02 (0.94–1.11), p=0.598, per 0.1 increase).
When adding the MPI to the updated Age, Dyspnea and Obstruction (ADO) index, MPI provided incremental prognostic information beyond the updated ADO index, as determined from a significant increase in the Harrell's C-statistics (0.785 to 0.792, p=0.003).

Conclusion
Presence of OL is associated with subtle impairment of left ventricular systolic function, impaired left ventricular diastolic function, and higher MPI. MPI is an independent predictor of mortality in people with OL and provides incremental prognostic information regarding all-cause mortality in this population.

Acknowledgement/Funding
Herlev & Gentofte University Hospital PhD fund