FEV1 Thresholds for Bronchial Thermoplasty: Is Adhering to Guidelines Necessary?

Abstract

INTRODUCTION: As bronchial thermoplasty (BT) gains momentum across the nation for the treatment of severe refractory asthma, logistical questions arise regarding the manufacturer guidelines for use of FEV1 in determining patient eligibility and need for hospitalization post-procedure. Currently, the recommendations are to perform BT only in patients with preprocedure FEV1 >65% and not discharge patients who have >20% drop in FEV1 post-procedure. We present a case of BT in which these guidelines were not adhered to, and yet the patient did extremely well without complications. CASE PRESENTATION: A 48 year-old Armenian male with severe refractory asthma was referred by his allergist to our institution for BT. Despite use of high-dose Dulera, Spiriva, Theophylline, Singulair, and Xolair, he still had chest tightness and dyspnea on exertion and required frequent rescue bronchodilators. The patient's baseline FEV1 was 63% and his CT scan showed evidence of mild focal bronchiectasis in the RUL. Nevertheless, we decided to proceed with BT given his potential quality of life benefits. The first procedure went smoothly with 85 actuations completed. However, the patient's postprocedure FEV1 dropped 49% from baseline, even though he clinically felt fine. After many hours of observation and debate, we finally discharged him home. The patient did well without any exacerbations. He underwent three more BT procedures in which his FEV1 parameters fell outside of recommended thresholds. Not only were all of his post-procedural FEV1 drops significantly greater than 20% (range -33% to -49%), but his pre-procedural FEV1 steadily declined with each subsequent session (63% to 56% to 46% to 45% of predicted). Yet the patient himself felt great and his exam was unremarkable, so we became comfortable performing BT and discharging him home despite the alarming values. Of note, this is also the first report of a patient requiring more than three BT sessions to complete the procedure. Because his LUL required 122 actuations, and continued viability of the catheter was uncertain, we decided to treat the RUL in a separate session three weeks later. At that time, we purposely did not ablate overtly bronchiectatic airways to avoid triggering potentially lifethreatening hemoptysis. Amazingly, despite his high-risk profile for this procedure, the patient has not had another asthma exacerbation to date. He now only requires rescue inhalers a few times a month and his allergist is beginning to de-escalate his medication regimen. DISCUSSION: Although safety concerns justify establishing FEV1 guidelines for BT, there is no actual clinical data validating the use of these thresholds for decision-making. Indeed, FEV1 may be a poor marker for post-BT asthma improvement since it did not change significantly in any major clinical trial, and is therefore not considered an outcome measure (1-3). Furthermore, in the COPD literature, FEV1 can sometimes be surprisingly preserved in patients with evidence of severe emphysema on high-resolution CT scan, thus suggesting the potential fallability of this method in assessing severity of obstructive lung disease. CONCLUSIONS: We present a case in which, by FEV1 values, the patient should have never had BT performed or been directly discharged home post-procedure. Yet this patient exceeded all expectations and did extremely well. Future studies are therefore needed to define the role of FEV1 measurements in bronchial thermoplasty.