P250 A six year follow up study of patients undergoing Cardiopulmonary Exercise Testing (CPET) for investigation of unexplained breathlessness

Introduction and Objectives Cardiopulmonary exercise testing (CPET) is a powerful diagnostic tool for investigating unexplained breathlessness. As well as diagnosing pathology, excluding harmful causes can reassure patients and help clinicians avoid over-investigation. Since 2013, Nevill Hall Hospital has offered CPET as the first line test for unexplained breathlessness if a diagnosis remains unclear after history, examination and basic clinic testing (figure 1). We have followed the cohort of 46 patients tested in 2013 to assess the impact of a ‘negative’ CPET on future secondary care use and the frequency of missed pathology. Methods We retrospectively reviewed the electronic case records of all 46 patients to 31st December 2019. We collected CPET outcomes, duration of follow up, number of subsequent referrals back to secondary care for breathlessness and the number and results of subsequent specialist investigations. We examined all secondary care correspondence for subsequent diagnoses of cardiovascular or pulmonary disease, even if breathlessness was not the presenting complaint. Results 90% (41/46) of CPETs showed no evidence of harmful pathology. Of these, just over half (24/41) showed positive evidence of dysfunctional breathing and a quarter (12/41) of deconditioning; 90% (37/41) were discharged within one appointment. One-third (13/41) were later either referred back to secondary care (8/41), frequented acute medical services (3/41) or accessed further specialist testing through secondary care (9/41) for the same complaint of breathlessness. Only one re-referral led to a new diagnosis (of COPD, six years after CPET) and of 29 additional investigations for the nine patients who underwent repeat testing, no additional diagnoses were found. 4% (2/41) were later diagnosed with a pathology potentially ‘missed’ by their CPET. One patient had a paroxysmal arrhythmia, not present at time of CPET. The second presented four months after CPET with myocardial infarction; their dysfunctional breathing pattern was so pronounced at CPET that they couldn’t reach adequate levels of exercise to reveal ischaemia. Conclusions This study provides support for use of CPET to reliably exclude harmful pathology and reassure both patients and clinicians early within a secondary care pathway for unexplained breathlessness. The diagnostic limitations of a sub-maximal test must be appreciated.