Age-, sex-specific Asian references established for right heart function via CMR

Cardiac magnetic resonance (CMR) can assess age- and sex-specific changes in right heart dimensions and function among Asians, helping doctors interpret disease states more accurately, according to a recent Singapore study.

“CMR is recommended for many patients at the time of the transition from paediatric to adult congenital heart disease programmes,” the researchers said, adding that this approach remains the gold standard for noninvasive measurement of right heart function. However, reference ranges in Asian population are lacking.

To contribute to the establishment of these references, the present study sought to describe the age- and sex-specific changes in right ventricular (RV) and atrial (RA) dimensions, as well as in systolic and diastolic parameters, in 360 healthy volunteers (mean age 50±17 years, 50 percent women). Assessments were performed using standard four-chamber cine CMR with fast feature tracking.

Among RV systolic functional parameters, ejection fraction (RVEF) and global longitudinal strain (RV GLS) were significantly higher in women than in men. On the other hand, no significant between-sex differences were reported for the peak systolic tricuspid annular velocity (S’) and tricuspid annular plane systolic excursion (TAPSE). [Front Cardiovasc Med 2021;8:664431]

RVEF was significantly and positively correlated with age in both men and women (p<0.0001 for both); S’ and TAPSE, in contrast, were inversely associated with age regardless of sex (p<0.0001 for all). Age showed no interaction with RV GLS.

In terms of RV diastolic function, women demonstrated significantly lower peak late diastolic tricuspid annular velocity (A’) than men, but a higher peak early-to-late diastolic tricuspid annular velocity ratio (E’/A’). In both sexes, E’ and E’/A’ ratio were significantly and inversely correlated with age.

Structurally, men showed significantly higher absolute and indexed RV end-diastolic (EDV), end-systolic (ESV), and stroke (SV) volumes than women (p<0.0001 for all). These RV volumes correlated inversely with age in both sexes (p<0.0001 for all).

Looking at RA parameters, the researchers found higher values of reservoir strain, conduit strain, and corresponding strain rates in women than in men. Booster strain and strain rate, in contrast, were comparable. Booster and conduit strain parameters were negatively associated with age in both sexes, while measurements for conduit strain showed positive correlations with age (p<0.0001 for all).

In terms of RA dimensions, age correlated positively with indexed RA longitudinal diameter in men and women (p<0.0001 for both). Additionally, indexed RA area was also associated with age in women alone (p<0.0001).

“This is the first study to establish age- and sex-specific reference ranges for CMR-derived tricuspid annular dynamic parameters, which are a prerequisite for clinical applicability and adoption,” the researchers said, noting that several limitations warrant future attention.

In particular, the current study employed a cross-sectional design and failed to collect CMR measurements across different time points, precluding a temporal analysis. “We need a longitudinal study with repeated CMR scans on the same individual, which can help us investigate how age affects the heart structural and functional changes,” they said.