Change in Management Following Bronchoscopy in Hematopoietic Stem Cell Transplant Patients With Pulmonary Infiltrates

Hematopoietic stem cell transplant (HSCT) is a modality that is increasingly utilized to treat various hematological disorders with a varying degree of success. From 2006 to 2019 use of HSCT worldwide has increased from 50,417 to an estimated 1.5 million. Disease relapse, graft versus host disease (GVHD) and infections are the leading causes of morbidity and mortality in patients with HSCT. Pulmonary complications, in particular, are common in patients with HSCT, and the diagnostic approach and management of these complications remain a challenge. Reasons for this possibly include a broad spectrum of etiologies, subtle and insidious clinical manifestations, non-specific radiological features, and limited biomarkers. On the other hand, surgical procedures to obtain lung biopsy, which is the ultimate diagnostic tool, are often contraindicated or present high risks to the patients. In this context, less invasive testing such as fiberoptic bronchoscopy (FOB) deserves further consideration. Previous studies showed that the yield of FOB, a low-risk procedure, may provide helpful information in the post HSCT patient with pulmonary infiltrates. However, the diagnostic yield and change in clinical decision making in those studies have been variable. Furthermore, all these studies were retrospective, with one exception.

The stem cell transplant activity in Saudi Arabia has increased exponentially in recent times, with more than 6000 stem cell transplants performed by 2016. Furthermore, the patient population is different regarding specific genetic and immunologic characteristics, underlying disorders and prevalent opportunistic pathogens. Therefore, this study was designed to prospectively evaluate the diagnostic value of FOB in those patients presenting with pulmonary infiltrates.

Study design and Method

This was a retrospective observational study of all patients who had HSCT and pulmonary infiltrates that required bronchoscopy. Data for demographics, clinical presentation, CT scan characteristics, FOB dates and details, microbiology, virology, cytology, histology, change in clinical decision making before and after FOB and 6 months outcome following bronchoscopy were collected.

Primary outcome

Rate of change in clinical decision making following FOB

Secondary outcome

Clinical characteristics associated with a positive yield in FOB CT scan characteristics associated with a positive yield in FOB Six month outcome of patients following FOB.

Statistics

Descriptive statistics for continuous variables were reported as mean ± standard deviation, and categorical variables were summarized as frequencies and percentages. The median and interquartile range (IQR) was used where appropriate.

Continuous variables were compared by independent Student's t-test/ANOVA or non-parametric (Mann Whitney U/Kruskal Wallis) test as appropriate, while categorical variables were compared by Chi-square test. Fisher's exact probability test was applied when examining variables of low incidence. Logistic regression was used to test the association between dependent and independent variables. The level of significance was set at a p-value < 0.05.

Inclusion criteria

• All patients who suffered from GVHD following Hematopoietic Stem Cell Transplant and had Pulmonary Infiltrate's requiring Fiberoptic Bronchoscopy.

Exclusion criteria

• Any patients aged less than 14 years.
• Unable to consent
• Those patients who the primary physician decided not have Fiberoptic Bronchoscopy.