BACKGROUND: Right ventricular (RV) adaptation is the main determinant of prognosis and survival in patients with pulmonary arterial hypertension (PAH). Ventriculo-vascular coupling is considered the gold-standard methodology for the physiologic assessment of RV adaptation, although due to its technical complexity and invasiveness, its broad application in clinical practice has been limited. Two-dimensional echocardiography is the most frequent clinical tool for assessment of right ventricular function, although there is scarce evidence assessing the association between the components of ventriculo-vascular coupling and echocardiography.
The study aimed to evaluate the association between echocardiographic metrics and components of ventriculo-vascular coupling in patients with advanced PAH, before and after treatment with parenteral treprostinil. An assessment of the association of echocardiographic metrics with cardiac magnetic resonance (CMR) indices of RV global function was also performed. Finally, we assessed the association between the different indices of RV performance with clinical outcomes.
METHODS: Data was obtained from the University of Arizona Pulmonary Hypertension (PH) registry, which prospectively enrolls patients with PH. Study patients were treatment-naïve and had advanced PAH. Data was obtained at baseline and after 3 months of therapy with parenteral prostacyclin, and included a right heart catheterization, two-dimensional echocardiography and CMR. The single-beat methodology was used for the estimation of ventriculo-vascular coupling. A linear regression model was used for the assessment of correlation between different echocardiographic metrics and components of ventriculo-vascular coupling, as well as between echocardiography and CMR. ANOVA testing was used for the assessment of changes between the different indices of RV performance and changes in the risk-stratification status, as a surrogate of clinical response.
RESULTS: A total of 45 patients were included in the analysis. The median age of participants was 56 years, 15.6% and 84.4% of study patients were functional class III and IV, respectively, reflecting the advanced PH. At baseline, fractional area change (FAC) had a moderate negative correlation with RV end-systolic elastance (Ees) and arterial elastance (Ea), r = −0.4 and −0.5, respectively; p < 0.05 for both. No association was seen at 3 months. All other echocardiographic metrics did not have a significant association. FAC also had a moderate association with RV ejection fraction (RVEF) and RV stroke volume/RV end-systolic volume (r = 0.5, p < 0.05 for both metrics), both at baseline and at 3-months. No association was noted with the other echocardiographic metrics. Patients that remained in a high-risk status despite therapy had higher values of Ea, and lower values of FAC and RVEF.
CONCLUSIONS: With the exception of FAC, there was poor correlation between echocardiographic markers of systolic function with both CMR and the different components of ventriculo-vascular coupling. The lack of association may be explained by the fact that ventriculo-vascular coupling allows for a physiologic assessment of load-independent intrinsic RV contractility (Ees), and its interaction with vascular load (Ea), while the systolic markers of function assessed by echo represent global RV function, which are different processes. Patients with persistent high-risk clinical status were more likely to have higher values of Ea than their counterparts despite therapy, an association that will have to be assessed in different studies.
|Commitee:||Rischard, Franz, Sivaram, Chittur, Zhang, Ying|
|School:||The University of Oklahoma Health Sciences Center|
|Department:||Clinical and Translational Science|
|School Location:||United States -- Oklahoma|
|Source:||MAI 81/7(E), Masters Abstracts International|
|Keywords:||Coupling, Pulmonary hypertension, Right ventricular adaptation|
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