Abstract
may be incorrect at high PVR values. This study sought to determine the accuracy of TTE PVR assessment compared to RHC. Methods: Patients undergoing a RHC assessment of pulmonary hypertension had TTE derived right heart pressure measurements performed the same day. Standard RHC and TTE right heart parameters were measured. RHC PVR was calculated using the formula PVR= [(mPAP−PCWP)/CO]× 80 dynes s cm−5. TTE PVR was calculated using the formula PVR=TRV× 10/TVI RVOT. Echocardiographers were blinded to the invasive data. Results: 100 patients were prospectively recruited. 77/100 had pulmonary hypertension (mean pulmonary artery pressure≥ 25mmHg). Two patients excluded in TTE arm due to no TR. Quality of TR signal envelope: complete 61%, incomplete 36%, absent 2%. Rhythm: Sinus 76%, AF 16%, paced 8%. Measurements (mean±SD): Age= 58.2± 13.6 years. Weight = 79± 19.4 kg. mPAP=34.1± 15mmHg.Time interval between RHC and TTE (mean±SEM)= 140.5± 11.3min. RHC PVR (mean±SEM)= 330.6± 36.1 dynes s cm−5. TTE PVR (mean±SEM)= 208.8± 10.3 dynes s cm−5. Correlation r= 0.7, p< 0.0001. Bland Altman (mean± 1.96 SDs) =−127.4± 457.2 to −711.9 dynes s cm−5. Conclusion: TTE guided assessment of PVR underestimates true RHC determined PVR by a mean of 127 dynes s cm-5 or 1.6 Woods Units (WU). The estimation becomes inaccurate once the PVR is approximately 200 dynes s cm−5 (2.5 WU) or above. The formula PVR=TRV× 10/TVI RVOT should not be used to estimate PVR in patients with known pulmonary hypertension. http://dx.doi.org/10.1016/j.hlc.2013.05.484
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