Impaired Cardiovascular Magnetic Resonance–Derived Rapid Semiautomated Right Atrial Longitudinal Strain Is Associated With Decompensated Hemodynamics in Pulmonary Arterial Hypertension

Abstract

Background The transition of right ventricle (RV) from a compensated to decompensated state contributes to survival in pulmonary arterial hypertension (PAH). This study investigates the significance of right atrial (RA) dysfunction on disease progression in PAH. Methods Eighty patients with PAH, including 58 with hemodynamically compensated RV function (PAH-C) and 22 with decompensated RV function (PAH-D), were compared with 80 age-matched and sex-matched normal controls. RA longitudinal strain and strain rate (SR) parameters corresponding to reservoir (total strain ε s and strain rate SR s ), conduit (passive strain ε e and strain rate SR e ), and booster pump (active strain ε a and strain rate SR a ) phases were derived by a rapid semiautomated method on cine cardiovascular magnetic resonance. Results In PAH compared with controls, significantly reduced RA strains and SRs were observed. Among patients with PAH, PAH-D had significantly impaired RA strains and SRs compared with PAH-C. RA total strain and passive strain were the best parameters for differentiating PAH-D from PAH-C. Lower RA strain correlated with increased RA pressure ( r =−0.57; P <0.0001), RV volume ( r =−0.37; P =0.002) and biomarker ( r =−0.53; P <0.0001), impaired RV function ( r =0.46–0.72; P <0.0001), and lower exercise capacity ( r =0.41; P <0.0001). Reduced RA strains were significantly associated with higher risk of clinical worsening in PAH. RA passive strain was the best predictor of a composite adverse event end point (Harrell’s C statistic,0.75; hazard ratio,0.84; P =0.019) compared with other conventional RA and RV functional measurements. Conclusions RA phasic functions are impaired in PAH. Among patients with PAH, impaired RA strains reflect RV decompensation and higher risks and predict adverse clinical outcomes. Clinical Trial Registration https://www.clinicaltrials.gov . Unique identifier: NCT02790918.

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

“…The importance of right atrial volume (Fig. 1(D) ) and function is becoming more clear regarding the prognosis of patients with PAH [ 9 , 17 •, 20 , 21 ••, 22 , 23 ], as they have been shown to be associated with clinical worsening [ 9 ]. Patients with right atrial maximum volumes > 74 ml/m 2 doubled their risk for death or lung transplant compared with patients with normal right atrial volumes [ 17 •].…”

“…Regional RV function, such as myocardial strain (a deformation measured as a change in length; ∆ L / L ), RV fractional area change, and tricuspid annular plane systolic excursion (TAPSE), are regularly assessed in patients with PAH using echocardiography [ 1 , 2 ]. Novel techniques to characterize regional ventricular function with CMR are emerging [ 20 , 23 , 26 – 31 ]. However, and of note, echocardiographic and CMR equivalent measures are not directly interchangeable [ 32 ].…”

Cardiac Magnetic Resonance in Pulmonary Hypertension—an Update

“…Impaired right atrial (RA) strain and phasic function are a marker of disease severity. Reduced RA strain is associated with decompensated RV function and stiffness [48,49]. The advancement of fully automated myocardial strain analysis is likely to push its role in future research in the diagnosis and prognosis of PH [50].…”

Looking backwards: is it time to assess veno-atrial interactions in pulmonary arterial hypertension?

“…These clinical methods to assess RV diastolic stiffness rely on invasive assessments of RV diastolic pressure and the use of the single-beat method [10,15,17], whereas venous backflow fraction can be measured non-invasively using CMR alone. Few studies have addressed the "veno-atrial" interactions but recent work investigates the role of right atrial function in PAH using echocardiography and CMR imaging [18][19][20][21]. LENG et al [18] showed that impaired right atrial function is associated with decompensated haemodynamics and worse outcomes in patients with PAH [18].…”

“…Few studies have addressed the "veno-atrial" interactions but recent work investigates the role of right atrial function in PAH using echocardiography and CMR imaging [18][19][20][21]. LENG et al [18] showed that impaired right atrial function is associated with decompensated haemodynamics and worse outcomes in patients with PAH [18]. Venous backflow allows for a complex assessment of the interaction between right atrial function, RV diastolic function, intravascular volume status and venous congestion in a single non-invasive measurement that are not provided by current gold standards of right heart failure, such as right atrial pressure and right ventricular end diastolic pressure.…”