Low GLSRV heralds adverse outcomes in PAH patients

Aug 10 2015

By Lucy Piper, Senior medwireNews Reporter

Impaired global longitudinal strain of the right ventricle (GLSRV) predicts adverse outcomes in patients with pulmonary arterial hypertension (PAH), say investigators.

They found that GLSRV correlated significantly with conventional echocardiographic parameters of RV systolic function and, at or above a cutoff of –15.5%, predicted adverse clinical events with a sensitivity of 70% and a specificity of 77%.

Patients with this level of impaired GLSRV also had a lower rate of event-free survival and total survival at 4 years than did patients with preserved GLSRV, at 42% versus 80% and 57% versus 93%, respectively.

A total of 51 patients participated in the study, the majority (61%) of whom had World Health Organization class II PAH. The patients’ GLSRV, which included the RV free wall and interventricular septum, was –16.1%, on average, which James Thomas (Northwestern Memorial Hospital, Chicago, Illinois, USA) and co-workers note is considerably lower than the normal value of about –28.0%.

“In PAH patients, chronic pressure and volume overload of RV leads to both structural and functional changes”, they explain in the Journal of Cardiovascular Ultrasound.

GLSRV correlated significantly with RV fractional area change, tricuspid annular plane systolic excursion and RV Tei index, as well as with pulmonary vascular resistance and B-natriuretic peptide concentration.

During a follow-up of 45 months, 12 patients died, two underwent lung transplantation and 15 were admitted to hospital due to worsening heart failure. The only factors predictive of these events after multivariate analysis were GLSRV and age.

Not only was a lower GLSRV independently associated with adverse clinical events and death, it also improved the predictions associated with having a tricuspid annular plane systolic excursion below 1.5 cm or pericardial effusion.

The researchers acknowledge that “[a] prospective study with a large number of patients with an objective comparison method will be needed to confirm the correlations and the clinical impact of this [GLSRV] measurement.”

But point out that “[w]ith RV strain validated as an important prognostic variability in PAH patients, it will be critical to test whether it can serve as a surrogate endpoint for novel therapies in PAH.”

They conclude: “If improvement in GLSRV with vasodilator or other intervention identifies those with better clinical outcomes, then drug development in PAH could be accelerated.”

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