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18-06-2015 | Pulmonary hypertension | News | Article

Right ventricular dyssynchrony may be prognostic in PAH

medwireNews: Researchers report that right ventricular dyssynchrony (RVD) may be a useful prognostic factor in patients with pulmonary arterial hypertension (PAH), improving the predictive accuracy of established risk factors.

Adding this variable to a model containing World Health Organization (WHO) functional class IV, 6-minute walk test and cardiac index significantly increased its accuracy for discriminating between patients with and without clinical worsening from 74% to 81%.

Furthermore, the team found that almost all of the patients who did not have clinical worsening were free of RVD at diagnosis, “emphasizing the potential role in clinical practice.”

They say: “Because of its high negative predictive value, physicians could be reassured on a more favorable course of the disease for those patients without RVD at diagnosis, especially if matching with other well-known predictive functional and hemodynamic variables.”

Researcher Roberto Badagliacca (Sapienza University of Rome, Italy) and colleagues measured the time to peak systolic strain of the four mid-basal RV sections and defined RVD as a standard deviation of the four segments (RV-SD4) greater than 18 ms.

According to this definition, RVD was present in 48 (60%) of the 80 PAH patients in the study, and these patients had more advanced WHO functional class, more right ventricular remodelling  and worse haemodynamics than patients without RVD.

During 12 months of follow-up, 26 (32.5%) patients experienced clinical worsening, and 24 (92.3%) of these patients had RVD; the average RV-SD4 was 45 ms among patients with clinical worsening versus 19 ms in those without.

The team identified an RV-SD4 of 23 ms as the best threshold for identifying patients at risk of clinical worsening. This had a particularly high sensitivity, of 92%, and negative predictive value, of 95%. The specificity and positive predictive value were 63% and 57%, respectively.

During follow-up, patients with clinical worsening had a significant increase in RV-SD4, whereas those without had a significant reduction, from 19.57 to 14.96 ms. Of note, the researchers found a significant relationship between RVD and peripheral vascular resistance (PVR), such that RV-SD4 improved in patients with large reductions in PVR. Indeed, RV-SD4 completely normalised in 10 patients with an average 42% reduction in PVR.

“Our findings should be confirmed in a larger multicenter trial focusing on changes in RVD during targeted PAH therapy and its impact on survival”, the team concludes in JACC Cardiovascular Imaging.

By Eleanor McDermid

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