2026/05/18 by Saeed Torbati, Colm McCabe · 1 voice
Medicine · #Cardiac Valve Diseases and Treatments #Cardiovascular Function and Risk Factors #Pulmonary Hypertension Research and Treatments
paper · doi:10.1002/resp.70264
openalex publication_date 2026/05/18 · openalex created_date 2026/05/19 · openalex updated_date 2026/06/04
Despite improvements in survival of chronic thromboembolic pulmonary hypertension (CTEPH) patients following pulmonary endarterectomy (PEA) within expert surgical centres [1], rates of postoperative morbidity remain non-trivial, emphasising the need to better understand factors that predict early postoperative risk. Complications such as reperfusion pulmonary oedema (RPE), airway haemorrhage and prolonged ventilation lead to longer postoperative lengths of stay within the intensive care unit (ICU), which itself mandates complex multidisciplinary management. In such a context, straightforward predictors of short-term postoperative recovery are of value, considering the need to further optimise both survival to hospital discharge as well as longer term outcomes. An elevated ratio of right atrial pressure to pulmonary artery wedge pressure (RAP/PAWP) reflects an imbalance in right and left heart filling pressures and has been linked with right ventricular dysfunction and worse survival in pulmonary arterial hypertension (PAH) [2]. Elevated mean RAP at right heart catheterisation (RHC) has also identified higher in-hospital mortality risk in several other cardiovascular disorders within a multivariable model [3]. The development of right ventricular dysfunction leads to an increase in RAP that, with increasing right heart afterload, rises disproportionately to PAWP; hence, an abnormally elevated RAP/PAWP ratio may provide insight into the development and progression of right heart failure [4]. As a clear example of such an imbalance, unoperated CTEPH increases pulmonary vascular load, typically with maintained left-sided filling pressures [1, 5]. In this setting, an elevated RAP/PAWP ratio derived from routine RHC emerges as a potential haemodynamic phenotype conferring elevated risk. Building on their earlier evaluation of this ratio [6], in a recent publication in Respirology, Chan et al. evaluate a large cohort of 462 CTEPH patients treated by PEA who in the immediate postoperative period have undergone further haemodynamic measurement [5]. Grouping patients by preoperative measurement of a RAP/PAWP ratio ≥ or < a prespecified cut-off of 1, they show that the former group not only had a poorer baseline functional status and worse haemodynamic profile but also experienced greater postoperative morbidity with a higher incidence of RPE, need for re-intubation and longer length of ICU stay. This supports the conclusion that this ratio may reflect a clinically relevant vulnerability during early postoperative recovery. Critically, this association remained using both a pragmatic cut-off threshold (RAP/PAWP ≥ 1) as well as with the use of continuous modelling, suggesting a graded rise in postoperative complication risk. In high-volume PEA centres, including that of the authors, the exceptionally low mortality rate (< 2%) has allowed the focus of risk management to evolve from survival to the mitigation of postoperative morbidity. Preoperative haemodynamic evaluation represents one of the cornerstones of surgical risk stratification in CTEPH and the authors are to be congratulated on their clear evaluation of the RAP/PAWP ratio alongside contemporaneous echocardiography, which informs on any influence of left ventricular dysfunction towards a metric that incorporates PAWP. More severe haemodynamic derangement confers elevated complication risk, and although mechanistic insight into the relevance of an elevated RAP/PAWP ratio to the occurrence of postoperative complications may be incomplete, these findings add to the tailoring of perioperative management. Predisposition to RPE in particular remains poorly understood, which in CTEPH may arise from surgical restoration of pulmonary blood flow to previously non-perfused territories [7]. Conceptualisation of increased risk of RPE in those with greater preoperative RV dysfunction and thus RAP/PAWP is therefore consistent. In contrast, preoperative mean PAWP values of 12.9 ± 4.8 mmHg in the RAP/PAWP < 1 group could infer an increased prevalence of occult left heart dysfunction, even though none was apparent on routine assessment. These findings underscore the importance of meticulous preoperative haemodynamic evaluation in CTEPH, serving also as a reminder that accurate determination of PAWP may be complicated by the presence of proximal vascular obstructions. Acknowledging the limitations of a single centre, retrospective observational patient cohort in whom data availability around diuretic optimisation is lacking, the use of a simple haemodynamic ratio of right and left heart filling pressures potentially adds to the standard measure of vascular load, PVR, which is independently prognostic of CTEPH outcomes. In contrast, the RAP/PAWP ratio refers indirectly to ventricular responses and whether such a chamber-specific relationship retains long-term prognostic value beyond more established indices remains an open question. In addition, its consistency, especially in milder haemodynamic severities of CTEPH, where RV dysfunction may be poorly captured by routine haemodynamic assessment emergent from the broadened haemodynamic definition of CTEPH, merits further attention [8]. The findings of this study should serve as a timely recommendation to clinicians involved in perioperative management of CTEPH, which potentially support additional close monitoring of a more vulnerable patient group in terms of postoperative fluid stewardship and ventilatory function. It should be emphasised that its greatest value lies in its potential use as a tool for perioperative planning and not for instance in the determination of operability or in the exclusion of patients as surgical candidates. As such, the RAP/PAWP ratio should be regarded as a hypothesis-generating measurement perhaps initially for surgical or critical care pathway optimisation. Further avenues for its deployment may of course emerge, including the potential for incorporation within perioperative risk prediction models, as well as a predictive tool in patients considered for balloon pulmonary angioplasty or perhaps hybrid procedures where changes in pulmonary vascular load and right ventricular function are highly associated with clinical outcomes [9, 10]. Serial assessment of RAP/PAWP may also be informative, looking beyond the immediate postoperative period with the potential to better plan deployment of ICU resources in patients at higher risk. As we strive for improved surgical outcomes in CTEPH with increasingly complex intervention strategies, the reincorporation of simple haemodynamic metrics may yet bear fruit. The authors have nothing to report. The authors declare no conflicts of interest.