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Critical Care and Perioperative Management

Category: Scientific Abstract: Oral/Poster

The New Pulmonary Hypertension Definition and Lung Transplant Outcomes

A. Krishnan1, E. Heng2, A. Garrison2, M. Fawad2, S. Elde3, B. A. Guenthart4, Y. Woo5, J. MacArthur2
1Stanford University, Cardiothoracic Surgery, Palo Alto, California 2Stanford University School of Medicine, Palo Alto, California 3Stanford University, Stanford, California 4Stanford Health Care, San Jose, California 5Stanford University School of Medicine, Stanford, California

    Presenting Author(s)

  • Aravind Krishnan, MD

    Resident
    Stanford University, Cardiothoracic Surgery
    Palo Alto, California, United States

Disclosure(s):
Aravind Krishnan, n/a: No financial relationships to disclose


Purpose: The 6th World Symposium on Pulmonary Hypertension in 2019 broadened the definition of pulmonary hypertension (PH) (mean pulmonary artery pressure [mPAP] ≥25 mmHg) to include lower mPAP (≥20 mmHg) with elevated pulmonary vascular resistance (PVR) (≥3 Wood Units [WU]). How this definition change impacts lung transplantation (LT) is unknown.

Methods: The Scientific Registry of Transplant Recipients (SRTR) was used to identify all adult (>18 years) LT recipients between January 2015 and March 2023 with mPAP≥20 mmHg. Patients were subdivided into two categories: 1) patients transplanted after 2019 with 20≤mPAP < 25 mmHg and PVR < 3WU or mPAP>25, and 2) patients transplanted between 2015 and 2019 with mPAP≥25 mmHg. The primary outcome was all-cause mortality at 1 year. Unadjusted Kaplan Meier (KM) survival analysis and adjusted Cox proportional hazards modeling were used to assess outcomes. Akaike information constant-optimized multivariate models were constructed from stepwise forward selection of characteristics that demonstrated univariate association with the outcomes of interest.

Results: A total of 10,328 adult patients who underwent lung transplantation during the study period were included. The mean (±SD) age at transplant was 57 (±12) years. More transplants were performed after the definition change in 2019 (n=6,207; 60.1%); 4,121 patients (39.9%) were transplanted with mPAP≥25mmHg between 2015 and 2019, 5,506 (53.3%) were transplanted after 2019 with mPAP≥25mmHg, and 701 (6.8%) were transplanted after 2019 with 20≤mPAP < 25 mmHg with PVR≥3. Median survival on KM analysis was not significantly different between groups (p=0.26) (Fig. 1). On multivariate survival analysis, survival after transplantation under the updated definition of PH was comparable to the classical definition (HR: 1.05, 95% CI: 0.95-1.16, p=0.33).

Conclusion: The updated definition of pulmonary hypertension includes more patients in the diagnosis of PH. More transplants were performed for pulmonary hypertension since the definition was updated compared to over a similar time period prior to the definition change. Patients who underwent lung transplantation under the updated definition of PH had similar outcomes to those prior, supporting the expansion of criteria to include patients at lower mean pulmonary artery pressures with sufficient PVR.

Identify the source of the funding for this research project: Institutional