Endobronchial Optical Coherence Tomography for Low-Risk Microscopic Assessment and Diagnosis of Idiopathic Pulmonary Fibrosis In Vivo

Comprehensive volumetric microscopy of epithelial, mucosal and endothelial tissues in living human patients would have a profound impact in medicine by enabling diagnostic imaging at the cellular level over large surface areas. Considering the vast area of these tissues with respect to the desired sampling interval, achieving this goal requires rapid sampling. Although noninvasive diagnostic technologies are preferred, many applications could be served by minimally invasive instruments capable of accessing remote locations within the body. We have developed a fiber-optic imaging technique termed optical frequency-domain imaging (OFDI) that satisfies these requirements by rapidly acquiring high-resolution, cross-sectional images through flexible, narrow-diameter catheters. Using a prototype system, we show comprehensive microscopy of esophageal mucosa and of coronary arteries in vivo. Our pilot study results suggest that this technology may be a useful clinical tool for comprehensive diagnostic imaging for epithelial disease and for evaluating coronary pathology and iatrogenic effects.

Current guidelines recommend surgical lung biopsy for diagnosis of interstitial lung diseases (ILDs) in selected patients. To shed light on the risk-benefit ratio for this recommendation, we examined the morbidity and mortality associated with video-assisted thoracoscopic surgical (VATS) lung biopsy in a group of outpatients. A retrospective cohort study was conducted of 68 consecutive ambulatory patients with radiographically apparent interstitial lung disease (ILD) referred for VATS biopsy during a 6-year period. Incidence of postoperative mortality, prolonged air leaks, pneumonias, and re-admissions were calculated. Risk factors for complications of surgery were examined. Three deaths occurred within 60 days after biopsy for a mortality rate of 4.4% (95% confidence interval [CI], 1% to 12%), and 19.1% (95% CI, 11% to 31%) experienced one or more complications of surgery. Risk factors for morbidity included preoperative dependence on oxygen therapy and pulmonary hypertension. The three patients who died had usual interstitial pneumonia on their biopsy specimen and were reintubated postoperatively for acute lung injury. Aggregation of articles published over the past 10 years reporting on surgical lung biopsy for the diagnosis of ILD yielded a postoperative mortality rate of 2% to 4.5%. VATS lung biopsy for diagnosis of ILD, even in ambulatory patients, is not an entirely benign procedure. Biopsy rarely may trigger an acute exacerbation of usual interstitial pneumonitis. The risk of postoperative complications appears to be greatest in those dependent on oxygen and those who have pulmonary hypertension. This information may be used in weighing the risk-benefit ratio of biopsy in individual patients.

Usual interstitial pneumonia (UIP) is a specific histological pattern of interstitial pneumonia most often associated with the clinical syndrome of idiopathic pulmonary fibrosis (IPF). There is controversy regarding the use of surgical lung biopsy in the diagnosis of UIP, and the risk of lung biopsy in these patients is largely unknown. This study investigated the 30 day surgical mortality rate in patients undergoing surgical lung biopsy for UIP. Patients undergoing surgical lung biopsy over a 10-yr period from 1986-1995 with the ultimate diagnosis of UIP (with or without underlying connective tissue disease) were identified. Pathology, computed tomography, medical records, and survival were assessed. Ten of sixty patients with usual interstitial pneumonia were found to be dead within 30 days of surgical biopsy. All of these were patients with idiopathic UIP, unassociated with connective tissue disease (clinical condition of IPF). In conclusion, patients with usual interstitial pneumonia of the idiopathic type, who present with atypical features, may be at higher risk for death following surgical biopsy than patients presenting with more typical features or patients with other interstitial illnesses.