The New Idiopathic Pulmonary Fibrosis Acute Exacerbations Document: One Step Ahead but Still Suspended in the Air

Acute Exacerbation of Idiopathic Pulmonary Fibrosis With Pirfenidone and Nintedanib: A Friend or Foe

Acute exacerbation (AE) in idiopathic pulmonary fibrosis (IPF) is unfortunate a deadly event with a very high mortality rate. Its occurrence is highly unpredictable, though few baseline risk factors have been identified. The revised definition of AE is more precise with clarity on defined parameters. However, no clear guidelines exist on treatment, with most therapies showing inconsistent benefits. Both the approved anti-fibrotic (pirfenidone and nintedanib) have shown equal efficacy in reducing the decline in lung functions, with few studies suggesting a drop in AE. We report a case of a patient with IPF with mildly impaired lung functions who was initiated on pirfenidone with dose titrated on a weekly basis but developed AE-IPF on day 10 of starting pirfenidone and after four days of doubling the dose from 600 mg/day to 1,200 mg/day. This raised the suspicion of whether pirfenidone played any role in this unfortunate event. With no response to conventional therapy of steroids and non-invasive ventilation for AE-IPF, initialization of nintedanib led to recovery with discharge of the patient in two weeks of hospitalization. This case highlights inadequacy in knowledge about the effects of these anti-fibrotics in IPF and recommends close monitoring in the future.

Clinical predictors and explant lung pathology of acute exacerbation of idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is characterised by constant threat of acute exacerbation of IPF (AE-IPF). It would be significant to identify risk factors of AE-IPF. We sought to determine the prognostic value of lung transplantation candidacy testing for AE-IPF and describe explant pathology of recipients with and without AE-IPF before lung transplantation.

Methods

Retrospective cohort study of 89 IPF patients listed for lung transplantation. Data included pulmonary function testing, echocardiography, right heart catheterisation, imaging, oesophageal pH/manometry and blood tests. Explanted tissue was evaluated by pulmonary pathologists and correlated to computed tomography (CT) findings.

Results

Out of 89 patients with IPF, 52 were transplanted during stable IPF and 37 had AE-IPF before transplantation (n=28) or death (n=9). There were no substantial differences in candidacy testing with and without AE-IPF. AE-IPF had higher rate of decline of forced vital capacity (FVC) (21±22% versus 4.8±14%, p=0.00019). FVC decline of >15% had a hazard ratio of 7.2 for developing AE-IPF compared to FVC decline of <5% (p=0.004). AE-IPF had more secondary diverse histopathology (82% versus 29%, p<0.0001) beyond diffuse alveolar damage. There was no correlation between ground-glass opacities (GGO) on chest CT at any point to development of AE-IPF (p=0.077), but GGO during AE-IPF predicted secondary pathological process beyond diffuse alveolar damage.

Conclusions

Lung transplantation candidacy testing including reflux studies did not predict AE-IPF besides FVC absolute decline. CT did not predict clinical or pathological AE-IPF. Secondary diverse lung pathology beyond diffuse alveolar damage was present in most AE-IPF, but not in stable IPF.

Transplant candidacy testing fails to predict acute exacerbation of IPF besides FVC absolute decline. Patients transplanted during acute exacerbation of IPF reveal multiple secondary lung histopathological processes beyond the expected DAD.https://bit.ly/3e1CPjO

Acute exacerbation of idiopathic pulmonary fibrosis: lessons learned from acute respiratory distress syndrome?

Idiopathic pulmonary fibrosis (IPF) is a fibrotic lung disease characterized by progressive loss of lung function and poor prognosis. The so-called acute exacerbation of IPF (AE-IPF) may lead to severe hypoxemia requiring mechanical ventilation in the intensive care unit (ICU). AE-IPF shares several pathophysiological features with acute respiratory distress syndrome (ARDS), a very severe condition commonly treated in this setting.A review of the literature has been conducted to underline similarities and differences in the management of patients with AE-IPF and ARDS.During AE-IPF, diffuse alveolar damage and massive loss of aeration occurs, similar to what is observed in patients with ARDS. Differently from ARDS, no studies have yet concluded on the optimal ventilatory strategy and management in AE-IPF patients admitted to the ICU. Notwithstanding, a protective ventilation strategy with low tidal volume and low driving pressure could be recommended similarly to ARDS. The beneficial effect of high levels of positive end-expiratory pressure and prone positioning has still to be elucidated in AE-IPF patients, as well as the precise role of other types of respiratory assistance (e.g., extracorporeal membrane oxygenation) or innovative therapies (e.g., polymyxin-B direct hemoperfusion). The use of systemic drugs such as steroids or immunosuppressive agents in AE-IPF is controversial and potentially associated with an increased risk of serious adverse reactions.Common pathophysiological abnormalities and similar clinical needs suggest translating to AE-IPF the lessons learned from the management of ARDS patients. Studies focused on specific therapeutic strategies during AE-IPF are warranted.