Reply To: “Pulmonary Artery Dilatation in Different Causes of Pulmonary Hypertension”

Caputo Annalisa, Scoccia Gianmarco

https://doi.org/10.1002/pul2.70175

We read with great interest the recent article by Xi et al. entitled “Pulmonary artery dilatation in different causes of pulmonary hypertension.” The authors provide a comprehensive evaluation of more than one thousand patients with different subtypes of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), showing that pulmonary artery (PA) dilatation is a common finding but does not independently predict survival. Their conclusion that only the 6-min walk distance serves as an independent prognostic marker highlights the complexity of interpreting PA size in clinical practice.

Several previous studies support and expand these observations. Badagliacca et al. [1] demonstrated in a cohort of patients with severe PH that although PA dilatation was present in more than 75% of cases, it had no prognostic impact, with outcomes instead determined by functional class and disease etiology. Similarly, Duijnhouwer et al. [2] confirmed that PA diameter measured at diagnosis did not independently predict mortality in PAH or CTEPH when established prognostic factors such as NYHA class, 6-min walk distance, and NT-proBNP were considered.

Nevertheless, other reports suggest that in selected contexts, PA enlargement may carry prognostic weight. Żyłkowska et al. [3] found that PA dilatation ≥ 48 mm was independently associated with unexpected death in PAH and CTEPH, raising concern for catastrophic complications such as rupture, dissection, or coronary artery compression. In connective tissue disease–associated PAH, Li et al. [4] showed that a main PA diameter ≥ 37.7 mm predicted poor long-term survival, identifying vascular enlargement as a risk marker in this subgroup. Finally, a systematic review and meta-analysis by Badea et al. [5] emphasized the potential clinical consequences of extreme PA dilatation, highlighting its association with left main coronary artery compression, with thresholds between 40 and 44 mm providing optimal accuracy for screening.

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