Cost Analysis: Use of Hydrogel Plug Tract Sealant System for CT-Guided Lung Biopsy can Reduce Patient Recovery Time and Cost

Purpose: To evaluate whether the use of the BioSentry hydrogel plug after a lung biopsy can reduce costs by safely shortening post-procedure observation time. Materials and methods: A single-center, retrospective review of percutaneous CT-guided core needle lung biopsies utilizing the hydrogel plug from May 2013-July 2016 was performed. Post-procedurally, patients were observed either for 3 hours with chest radiographs obtained at 1 and 3 hours, or for 1.5 hours with one chest radiograph. Biopsy-related cost data was supplied from the institution’s finance department. Results: A total of 235 patients were analyzed for pneumothorax rates (124 patient in 3-hour recovery group and 111 patients the 1.5-hour group). Pneumothorax rate on follow-up chest radiographs was 22% vs 13% in the 3-hour vs 1.5-hour recovery groups, and chest tube insertion rate was 3.9% vs 0%, respectively. In a 30-day follow-up available in 96% of patients, the 3- and 1.5-hour groups each had 1 patient hospitalized for delayed complications but neither required chest tube placement. Discharging patients if absent or small stable pneumothorax detected on 1.5-hour post-lung biopsy recovery chest radiograph resulted in total cost savings of $686 (P < 0.05) and recovery cost savings of $487 (P < 0.001) on average per patient. Conclusion: Hydrogel plug use and early discharge at 1.5 hours resulted in significant cost savings. 1.5-hour observation is safe for routine lung biopsies, while a longer observation is recommended for complicated patients or technically challenging biopsies.


Introduction
Demand for lung biopsy is increasing with rising lung cancer rates, higher detection rates of incidental pulmonary nodules, and greater need for tissue sampling for new molecular testing [1].
CT-guided percutaneous core needle lung biopsy is the standard method for evaluating pulmonary lesions with 93-95% diagnostic accuracy [2][3][4]. Pneumothorax is the most common complication of the procedure, with incidence of approximately 20-25%, with 4-8% requiring chest tube placement [5][6][7]. Complications of lung biopsy can be a substantial economic burden, increasing costs by 300-400% [8,9]. There is great interest in reducing pneumothorax rates and lowering potential costs related to chest tube placement, additional imaging, hospital admission and stay.
Sealing the pleural puncture site after lung biopsy has shown to decrease pneumothorax rates. Various sealant materials have been investigated, including hydrogel plug, autologous blood by the Food and Drug Administration to reduce the incidence of pneumothoraces following CT-guided lung biopsy. As such, multiple studies have demonstrated that the hydrogel plug decreased both pneumothorax rates (18-20% vs 31-33%) [10,11] and chest tube insertion rates (2% vs 10%) [12] compared to no sealant.
While clinical practices vary by institution and interventionalist, patients are typically monitored after routine lung biopsy for pneumothoraces with serial chest radiographs during recovery.
The post-procedural recovery period, often charged based on time, can be a significant portion of the lung biopsy costs. Given the efficacy of the hydrogel plug in reducing the risk of post-biopsy pneumothoraces, the aim of this study was to retrospectively evaluate if length of post biopsy recovery can be safely shortened with use of such a device at our institution.

Study subjects and selection criteria
After approval from the institutional review board (IRB #16-000217), we retrospectively reviewed electronic medical records and images of all percutaneous CT-guided core needle lung biopsies performed at our institution utilizing the BioSentry device from May 2013-July 2016. A total of 285 biopsies were performed utilizing the BioSentry hydrogel plug. Of these patients, 50 were excluded from our observational analysis for the following reasons: inpatient status (32), requiring chest tube placement [13], known BioSentry maldeployment during procedure [3], patient age < 18 years at time of biopsy [1], and pre-existing hydropneumothorax [1]. Therefore, a total of uncomplicated 235 core needle lung biopsies were available for further review.

Procedures and assessments
Three board-certified, fellowship-trained interventional radiologists (with 24, 12, and 8 years of experience) performed biopsies in a single institution. Using CT-guidance, 20-gauge core samples were percutaneously obtained via 19-gauge coaxial needle (Argon Medical Devices, Athens, Tex). The BioSentry hydrogel plug tract sealant was deployed through the same coaxial system using

Study outcomes and statistical analysis
Presence of pneumothorax on immediate post-procedure CT imaging was defined as none, non-actionable (small), or requiring chest tube. Post-procedure radiographs were also assessed for pneumothorax, which was defined as none, small if pleural air accumulation was < 2 cm from lung apex, and large if pleural air accumulation was > 2 cm from lung apex [13].
Biopsy-related cost data was supplied from our institution's finance department. Our EPSi costing system database was queried for all activity codes associated with the lung biopsy encounter.
Itemized cost and charge obtained for the biopsy encounter was obtained. The charge was defined as the amount asked by provider and was what appeared on medical bill, whereas the cost was the amount the insurance company and/or patient actually paid for health care services [14]. Total cost was defined as the sum of costs of all activity codes associated with the encounter. Recovery cost was defined as fee for post-procedure observation nursing care, charged per 15-minute intervals at our institution. Of the 235 total uncomplicated biopsy patients, 145 (62%) had available data for cost analysis, (53% and 79% of the 3-hour and 1.5-hour recovery groups, respectively).
Mann-Whitney U and independent t tests were performed for continuous nonparametric and parametric variables. Pearson chi squared tests were performed for categorical data. P < 0.05 was considered significant.

Patient demographics
A total of 235 patients who underwent core needle lung biopsies were reviewed ( Table 1). The mean patient age at time of biopsy was 67 years. Overall, there were even proportions of male and female (52% male) patients. The average nodule mean diameter was 19 mm, ranging from 3.5 -94 mm. The average nodule depth from pleural surface, measured from nodule periphery along needle shaft to pleural surface just prior to biopsy, was 39 mm.
Emphysema was present in the same lobe as the nodule in 16% of the biopsies. There was no statistically significant difference in these variables between the 3-and 1.5-hour recovery groups.

Pneumothorax rates
Analysis of pneumothorax rates included 11 of the 13 patients who required chest tube placement for pneumothorax. The other 2 chest tube patients were not included because pneumothoraces occurred after pleural puncture but before BioSentry deployment.

American Journal of Biomedical Science & Research
Copy@ Lee Shimwoo insertion (10-12). For comparison between the 3-and 1.5-hour recovery groups, additional 7 chest tube patients were removed from analysis given that they developed significant pneumothoraces on immediate post-procedural CT scans after BioSentry deployment, prompting chest tube placement immediately. Pneumothorax rate on follow-up radiographs was 22% vs 13% in the 3-and 1.5-hour recovery groups, and chest tube insertion rate was 3.9% vs 0%, respectively ( Table 2).

Cost Analysis
The costs and charges were compared between the 3-and 1.5-hour recovery groups, excluding chest tube placement patients ( Figure 1). In this study, we mainly focused on costs for our analyses since it is likely a more accurate reflection of what is generally referred to as "health care costs" incurred to the society.
The average total cost in the 1.5-hour recovery group was $4,469 (± 1,801) compared to $5,156 (± 2,051) in the 3-hour recovery group, resulting in average cost savings of $686 (P < 0.05) ( Table 3). The recovery cost was decreased by $487 (P < 0.001) in the 1.5-hour group. The use of BioSentry did not add significantly to the overall cost of the procedure due to the use of c-code for billing approved by the Center for Medicare and Medicaid Services to offset the cost of the device, as well as institutionally negotiated price.

Discussion
In our single-center retrospective study, we examined whether the use of a hydrogel sealant system after a lung biopsy can safely reduce costs by shortening post-procedure observation time.
Discharging routine lung biopsy patients in the absence of or a small stable pneumothorax after a 1.5-hour recovery resulted in total cost savings of $686 (P < 0.05) on average. Specifically, hours is $510, which is comparable to the actual cost saved.
There is strong interest in reducing costs related to lung biopsy.
Biopsy is the most expensive step in lung cancer diagnosis, and complications are not only detrimental to patients' health but can Our study had several limitations. More patients underwent shorter recovery in the later dates of data collection, which encaptures a period of evolving clinical practice at our institution.
Although there were no demonstrable differences in patient demographics between the 3-and 1.5-hour recovery groups, we could not account for all aspects of clinical decisions that determined recovery stay length given the retrospective nature of our study.
The finding of 0% pneumothorax rate in the 1.5-hour group may be due to such bias and/or due to not large enough sample size.
However, the results of the 30-day follow-up help show that the longer recovery times do not necessarily lead to more detection of clinically significant pneumothoraces. Another limitation is the lack of a control group without the use of BioSentry. In addition, cost data was missing in 38% of patients. The reasons for missing data are not fully elucidated although they may be related to patients' involvement in other research trials. Future prospective randomized studies on a larger scale are needed to further establish safe post-lung biopsy observation protocols.