Non-invasive measurement diagnostic tools for pulmonary hypertension

Abstract Background Pulmonary hypertension (PHTN) is a multi-causal pathology characterised by an increase in pulmonary pressures leading to heart failure and poor 5-year survival rate1. Right heart catheterization (RHC) remains the gold standard investigative tool to diagnose PHTN2. Although a relatively safe procedure, it carries a 1.3% adverse event rate, 0.055% risk of death3,4, 0.018% malignancy related radiation risk5, and high cost (estimated £1,442)6. Non-invasive measurement (NIM) tools such as transthoracic echocardiogram (TTE) and cardiac CT/MRI heart are safer but under-utilised in the diagnosis of PHTN. Purpose 1. Explore NIM tools as alternative to RHC in patients with PHTN. 2. Determine the accuracy of TTE parameters in comparison to RHC measurements. 3. Support the use of NIM tools for patients requiring long term monitoring for PHTN and for those unable to undergo RHC due to a variety of reasons. Methods A total of 36 eligible patients who were listed for RHC from 01/01/25 to 01/04/25 were identified via our institutes local RHC cath-lab list. TTE done within 6 months from their index procedure was included. Mean pulmonary artery pressure (mPAP) estimation was obtained using the simplified linear regression formula mPAP = (0.6x systolic PAP)+2 mmHg, and current European society of cardiology (ESC) TTE multi-parameter (TR Vmax, ventricles, pulmonary artery, inferior vena cava and right atrium measurements) for grading the probability PHTN were used against RHC mPAP measurements. An estimated mPAP of ≥20 mmHg, and intermediate/high probability of PHTN is considered positive for PHTN. We did not include CT/MRI measurements as there were inadequate data. Additionally, a PubMed search of the latest literature on NIM for PHTN was done to explore current and upcoming technological advancements in this sector. Results TTE estimated mPAP and multi-parameter TTE probability for PHTN positive predictive value were 83% and 56% respectively. Other measurements included sensitivity (60vs56%), Specificity (73vs65%), and negative predictive value (44vs65%) Picture 1. In comparison to the literature, sensitivity was lower (56-60% vs 83-89%), but other measures of diagnostic accuracy were similar7,8. PubMed literature search found several advancements in NIM diagnostic accuracy for PHTN such as using multiparametric cardiac MRI models (Sen:93%; Spe:79% NPV: 51%;PPV 94%)9, cardiac CT (Sen:79%; Spe:83%;Negative likelihood ratio:0.33;Positive likelihood ratio:3.83%)10, wearable Cardiosense’s Cardiotag device (Sen:85%;Spe:89%)11 , and Non-invasive filling pressure device (NIFP) (Sen: 71.4%; Spe:91%)12, Picture 2. Conclusion Although NIM tools are safe, affordable, easily accessible and relatively risk free, it does not yield reproducible diagnostic accuracy for PHTN and only remains as a good screening tool for now, however, new technology and software algorithms are being developed and may replace RHC in the near future.TTE diagnostic accuracy for PHTNFor image description, please refer to the figure legend and surrounding text. PubMed literature search on NIM toolsFor image description, please refer to the figure legend and surrounding text.