AIMS

Right ventricular (RV) dysfunction has been associated with worse prognosis in patients with diastolic dysfunction, highlighting the importance of early detection. Main pulmonary artery (MPA) compliance may indicate adverse biventricular coupling prior to emerging RV function.

METHODS AND RESULTS

Sixty-eight patients with suspected diastolic dysfunction (New York Heart Association ≥ II, LV EF ≥ 50%, E/e' ≥ 8) were prospectively recruited and underwent rest and stress right heart catheterization, echocardiography, and cardiovascular magnetic resonance imaging (CMR) within 24 h. Maximum ( ) and minimum ( ) MPA vessel area and stroke volume (RVSV) were obtained from CMR real-time phase-contrast images at rest and during exercise stress. Compliance was calculated as pulsatility and capacitance . Patients had systematic follow-up after 48 months. Occurrence of cardiovascular events was defined as the primary endpoint. A total of 63 patients [66 ± 9 years, 39 (61.9%) female] were eligible for final analyses. MPA and MPA were lower during exercise stress compared with rest (20% vs. 17.5%, = 0.034 and 0.26%/mL vs. 0.20%/mL, = 0.001). Subgroups with and without heart failure with preserved ejection fraction (HFpEF) had similar MPA compliance at rest, however, HFpEF patients had a steeper decrease of compliance during exercise stress (MPA 13% vs. 20%; < 0.001 MPA 0.16%/mL vs. 0.25%/mL, = 0.018). Decreasing MPA and MPA during exercise stress correlated with markers of diastolic dysfunction including pulmonary capillary wedge pressure, E/e', and HFA-PEFF score. Patients with decreased MPA (HR 6.0; = 0.016) and MPA (HR 11.3; = 0.015) had worse outcomes independent from conventional markers of diastolic dysfunction.

CONCLUSION

In patients with suspected diastolic dysfunction and preserved RV function, exercise-stress testing unmasked decreasing CMR-derived MPA compliance, associated with LV diastolic dysfunction and indicated higher risk for cardiovascular events.