{'fraction_non_alphanumeric': 0.03765690376569038, 'fraction_numerical': 0.030334728033472803, 'mean_word_length': 5.15112540192926, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Primary pulmonary hypertension as a risk factor for the development of obliterative bronchiolitis in lung allograft recipients.

STUDY OBJECTIVES
Obliterative bronchiolitis (OB) is a major factor limiting long-term survival after lung transplantation. The etiology of this disease process remains incompletely understood. Several risk factors have been identified previously, including acute rejection and cytomegalovirus pneumonitis. The purpose of this study was to evaluate primary pulmonary hypertension (PPH) as a potential risk factor for the development of OB after lung transplantation.


DESIGN AND PATIENTS
We retrospectively analyzed 107 lung allograft recipients (28 heart-lung, 18 bilateral sequential single-lung, 61 single-lung) who underwent transplantation between May 1, 1986, and April 30, 1994, and survived at least 3 months posttransplant. Mean follow-up posttransplant was 28.6 months (range, 3.5 to 99 months). Actuarial survival was estimated for patients with or without PPH and for those who did or did not develop OB.


RESULTS
In all, 25 patients (23.4%) developed OB, diagnosed by strict histologic criteria. Of 23 patients with PPH, 9 (39.1%) developed OB, compared with 16 (19.0%) of 84 patients without PPH (p = 0.044). Actuarial survival, sex, time on waiting list, and follow-up posttransplant were not significantly different between groups. PPH was the major determinant for the development of OB (p = 0.0468) when evaluating PPH and cytomegalovirus pneumonitis together as risk factors. Patients with PPH also developed OB significantly earlier posttransplant, compared with patients with other primary disease (p = 0.05).


CONCLUSIONS
Patients with PPH who undergo lung transplantation are at increased risk for the development of OB, which also occurs at a shorter time interval posttransplant. This subgroup needs aggressive monitoring for diagnosis and treatment of OB.