Importance of Tricuspid Regurgitation Velocity Threshold in Risk Assessment of Pulmonary Hypertension-Long-Term Outcome of Patients Submitted to Aortic Valve Replacement

ABSTRACT Background: The upper physiological threshold for tricuspid regurgitation velocity (TRV) of 2.8m/s proposed by the Pulmonary Hypertension (PH) guidelines had been questioned. The aim of this study was to evaluate the prognostic significance of preoperative PH in patients with aortic stenosis, long-term after valve replacement, using two different TRV thresholds (2.55m/s and 2.8m/s). Methods: 444 patients were included (mean age 73±9 years; 55% male), with a median follow-up of 5.8 years (98% completed). Patients were divided into three PH probability groups according to guidelines (low, intermediate and high) for both thresholds (TRV≤2.8m/s and TRV≤2.55m/s), using right atrial area>18cm2 and right ventricle/left ventricle ratio>1 as additional echocardiographic variables. Results: In patients with measurable TRV (n=304), the low group mortality rate was 25% and 30%, respectively for 2.55m/s and 2.8m/s TRV thresholds. The intermediate group with TRV>2.55m/s was an independent mortality risk factor (HR 2.04; 95% CI: 1.91 to 3.48, p=0.01), in contrast to the intermediate group with TRV>2.8m/s (HR 1.44; 95% CI: 0.89 to 2.32, p=0.14). Both high probability groups were associated with an increased mortality risk, as compared to their respective low groups. When including all patients (with measurable and non-measurable TRV), both intermediate groups remained independently associated with an increased mortality risk: HR 1.62 (95% CI 1.11 to 2.35 p=0.01) for the new cut-off point; and HR 1.43 (95% CI: 0.96 to 2.13, p=0.07) for guidelines threshold. Conclusions: A TRV threshold of 2.55m/s, together with right cavities measures, allowed a better risk assessment of patients with PH secondary to severe aortic stenosis, with or without tricuspid regurgitation.