{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T18:01:41Z","timestamp":1790100101810,"version":"4.0.1"},"reference-count":20,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T00:00:00Z","timestamp":1771459200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cardiovasc. Med."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Pulmonary arterial hypertension (PAH) is traditionally characterized as a rapidly progressive, fatal disease. Yet increasing evidence suggests that immune dysregulation, endothelial injury, and metabolic adaptation can sustain subclinical disease for decades before recognition.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case presentation<\/jats:title>\n                    <jats:p>We report a 73-year-old U.S. Army veteran with terminal PAH whose symptoms began in 1972\u2014nearly fifty years before diagnosis. Despite a childhood splenectomy and extensive exposure to pulmonary toxins during a 21-year career in military aviation (JP-4\/JP-8 fuels, asbestos, burn pits, and talc pleurodesis), no follow-up imaging was performed after retirement in 1992. After a 24-year gap, a 2016 chest x-ray revealed pulmonary artery enlargement consistent with pulmonary hypertension, but the finding was not pursued until 2021, when right-heart catheterization confirmed severe PAH with pulmonary artery pressures of 82\/29\u2005mm Hg (mean \u224847\u2005mm Hg). A transthoracic echocardiogram in October 2025 demonstrated an estimated right-ventricular systolic pressure (RVSP) of 66\u2005mm Hg with right-atrial pressure 8\u2005mm Hg, preserved biventricular function, normal ejection fraction (LVEF 68%), mild concentric left-ventricular hypertrophy, and only trace tricuspid and mitral regurgitation. Brain natriuretic peptide (BNP) levels remained normal, suggesting right-ventricular metabolic adaptation rather than decompensation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>\n                      This case supports a model of\n                      <jats:italic>slowly progressive PAH<\/jats:italic>\n                      driven by chronic immune imbalance from asplenia, toxin-induced oxidative stress, and nitric-oxide scavenging by free hemoglobin. Over decades, these mechanisms produced endothelial remodeling while right-ventricular metabolism shifted toward glycolysis (\u201cfetal-like\u201d adaptation), delaying failure. The patient's trajectory parallels post-COVID data linking endothelial inflammation and microvascular injury to delayed pulmonary hypertension.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>PAH can evolve silently across decades in individuals with immune or hematologic dysregulation. Recognition of immune-metabolic phenotypes and early screening of asplenic or toxin-exposed populations may enable earlier intervention and alter the disease's natural history.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fcvm.2026.1727803","type":"journal-article","created":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T09:36:31Z","timestamp":1771493791000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Case Report: Rethinking pulmonary arterial hypertension: immune and metabolic adaptations in a 34-year case of insidious progression"],"prefix":"10.3389","volume":"13","author":[{"given":"Bronwen","family":"Erickson-Keith","sequence":"first","affiliation":[{"name":"Independent Researcher","place":["Lynnville, TN, United 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