A New Tool for Transbronchial Cryobiopsies in the Lung: An Experimental Feasibility ex vivo Study

The Diagnostic Efficiency and Safety of Transbronchial Lung Cryobiopsy Using 1.1-mm Cryoprobe in Diagnosing Interstitial Lung Disease

INTRODUCTION

Transbronchial lung cryobiopsy (TBLC) is increasingly used to diagnose interstitial lung disease (ILD). The 1.1-mm cryoprobe has recently been available in clinical practice. The diagnostic yield and safety of TBLC using a 1.1-mm cryoprobe need to be confirmed.

METHODS

A prospective, randomized controlled trial was conducted in patients with suspected ILD and randomly assigned to 1.1-mm and 1.9-mm cryoprobe groups. The primary outcome was the diagnostic yield of multidisciplinary discussion. Secondary outcomes were sample quality and incidence of complications. The tension and stress effects during TBLC onto the target lobe caused by 1.1-mm and 1.9-mm cryoprobes were also evaluated using finite element analysis.

RESULTS

A total of 224 patients were enrolled. No significant differences were observed in the diagnostic yield (80.4% vs. 79.5%, p = 0.845) and sample quality scores (5.73 ± 0.64 vs. 5.66 ± 0.77; p = 0.324) between the 1.9-mm cryoprobe group and 1.1-mm cryoprobe group. The average surface areas of samples in 1.1-mm cryoprobe group were smaller, while no difference in sample weights was observed. A decreased incidence of moderate bleeding was found in the 1.1-mm cryoprobe group (17.0% vs. 6.2%, p = 0.027), while there was no difference in the incidence of the pneumothorax, there was a trend to higher rate of pneumothorax in 1.1-mm group. In finite element analysis, the 1.1-mm cryoprobe required the largest tension and produced the largest stress.

CONCLUSION

Compared with a 1.9-mm cryoprobe, there was no difference in specimen quality or diagnostic rate but smaller sample size with a 1.1-mm cryoprobe. There was a decreased risk of moderate bleeding, but a trend towards increased risk for pneumothorax with 1.1-mm cryoprobe.

TRAIL REGISTRATION

Clinicaltrials.gov identifier NCT04047667; registered August 4, 2019.

Defining Optimal Settings for Lung Cryobiopsy in End-Stage Pulmonary Disease. A Human, Ex Vivo, Diseased Lung Clinical Trial

BACKGROUND

To evaluate optimal settings of probe size, freezing time, and distance to the pleura that influence the size and quality of biopsy specimens during transbronchial lung cryobiopsies in ESPD.

METHODS

We prospectively recruited 17 patients undergoing lung transplantation. We created a nonperfused ex vivo bronchoscopy setting to perform multiple cryobiopsies with different probe sizes (1.7, 1.9, and 2.4 mm), freezing times (3, 5, 7, 10, 20, 30 seconds), and probe distance from pleura (5, 10, and 20 mm). Alveolated pulmonary parenchyma area≥50% in histology was considered a good quality biopsy, with a minimum procedural artifact. We used logistic regression to identify independent parameters as risk factors for histologic adequacy.

RESULTS

A total of 545 cryobiopsies were obtained from 34 explanted lungs after pneumonectomy for lung transplantation. The mean maximum diameter of the specimen achieved with the 1.7 probe was larger (13.5 mm) than those obtained with 1.9 and 2.4 mm probes (11.3 and 10.7 mm, P= 0.07). More pleural macroscopic damage and pleural tissue in histology occurred with the 2.4 mm probe ( P <0.001). There was no difference in the quality of specimens between the different freezing times and the distance from the pleura.

CONCLUSIONS

Freezing time and distance from the pleura did not affect the histologic quality for diagnosing ESPD in severely damaged lungs. Smaller cryoprobe size did not negatively affect sample adequacy.

Safety, utility and clinical efficacy of cryobiopsy of lung in paediatric population-A single centre experience

Background

Surgical lung biopsy (SLB) or video-assisted thoracic surgery (VATS) has been the traditional gold standard modality for diagnosing paediatric interstitial lung diseases. Cryobiopsy of the lung has recently been shown to be a novel technique with very good sensitivity and specificity in the diagnosis of various interstitial lung disorders in adults. Although there are a few case reports of the same in children, pediatric cryo lung biopsies are rarely performed due to the lack of the necessary equipment and the lack of expertise.

Methods

A retrospective single-centre study was conducted with twelve consecutive children with diffuse parenchymal lung disease diagnosed both clinically and on high-resolution computed tomography (HRCT) of the chest which were included in the study between October 2020 and September 2022 to measure the diagnostic yield and safety of the procedure. The site from where cryobiopsy was to be done was chosen after a multidisciplinary meeting with the paediatric radiologist.

Results

Twelve children (eight males and four females) were included in the study who underwent a cryobiopsy in the duration of two years. The mean age of the cases involved was 8 years and 3 months. With the youngest and oldest being 12 days and 15 years, respectively, all children underwent cryobiopsy as mentioned above. Diagnostic yield was achieved in 92% of cases.

Conclusion

Cryobiopsy is a valuable diagnostic tool in childhood interstitial lung diseases, which offers a less invasive option for obtaining lung tissue samples with a better yield which can aid in accurate diagnosis, a good safety profile and a shorter hospital stay. Our study emphasizes that in trained centres, TBCB is a safe, effective and less invasive way to obtain tissue diagnosis in children with ChILD.

Lung adenocarcinoma and squamous cell carcinoma difficult for immunohistochemical diagnosis can be distinguished by lipid profile

In patients with unresectable non-small cell lung cancer, histological diagnosis is frequently based on small biopsy specimens unsuitable for histological diagnosis when they are severely crushed and do not retain their morphology. Therefore, establishing a novel diagnostic method independent of tissue morphology or conventional immunohistochemistry (IHC) markers is required. We analyzed the lipid profiles of resected primary lung adenocarcinoma (ADC) and squamous cell carcinoma (SQCC) specimens using liquid chromatography-tandem mass spectrometry. The specimens of 26 ADC and 18 SQCC cases were evenly assigned to the discovery and validation cohorts. Non-target screening on the discovery cohort identified 96 and 13 lipid peaks abundant in ADC and SQCC, respectively. Among these 109 lipid peaks, six and six lipid peaks in ADC and SQCC showed reproducibility in target screening on the validation cohort. Finally, we selected three and four positive lipid markers for ADC and SQCC, demonstrating high discrimination abilities. In cases difficult to diagnose by IHC staining, [cardiolipin(18:2_18:2_18:2_18:2)-H]^- and [triglyceride(18:1_17:1_18:1) + NH4]⁺ showed the excellent diagnostic ability for ADC (sensitivity: 1.00, specificity: 0.89, accuracy: 0.93) and SQCC (sensitivity: 0.89, specificity: 0.83, accuracy: 0.87), respectively. These novel candidate lipid markers may contribute to a more accurate diagnosis and subsequent treatment strategy for unresectable NSCLC.

Diagnostic Utility and Safety of Non-Intubated Cryobiopsy Technique Using a Novel Ultrathin Cryoprobe in Addition to Conventional Biopsy Techniques for Peripheral Pulmonary Lesions

BACKGROUND

Transbronchial cryobiopsy enables high-quality sample collection around the probe tip. Meanwhile, existing cryoprobes have less flexibility and a higher risk of bleeding. The ultrathin cryoprobe with a 1.1-mm diameter addresses these problems and allows specimens to be directly retrieved through the working channel of a thin bronchoscope.

OBJECTIVE

This study evaluated the diagnostic utility and safety of non-intubated cryobiopsy using an ultrathin cryoprobe added to conventional biopsy for diagnosing peripheral pulmonary lesions (PPLs).

METHODS

The data of patients who underwent conventional biopsy followed by non-intubated cryobiopsy to retrieve specimens through the thin bronchoscope's working channel for diagnosing PPLs at Osaka Metropolitan University Hospital from July 2021 to June 2022 were retrospectively collected. They were analyzed to evaluate the diagnostic utility and safety of adding non-intubated cryobiopsy to conventional biopsy for PPLs. The characteristics of PPLs that obtain additional diagnostic benefits from cryobiopsy over conventional biopsy were also investigated.

RESULTS

The analysis included 113 patients. The diagnostic yields of conventional biopsy and non-intubated cryobiopsy were 70.8% and 82.3%, respectively (p = 0.009). The total diagnostic yield was 85.8%, higher than conventional biopsy alone (p < 0.001). Although one moderate bleeding occurred, no severe complications developed. The additional diagnostic benefits of non-intubated cryobiopsy over conventional biopsy were demonstrated when the radial endobronchial ultrasound (R-EBUS) showed "adjacent to" (60.3% vs. 82.8%, p = 0.017).

CONCLUSIONS

Non-intubated cryobiopsy using an ultrathin cryoprobe has high diagnostic utility and safety for diagnosing PPLs, with additional diagnostic benefits over conventional biopsy depending on the R-EBUS image.

[Complicated hematomediastinum in a 76-year-old patient after performing an endosonographically guided transbronchial cryobiopsy (EBUS-TBCB) with suspected lymphoma]

We present the case of a patient with severe complications from mediastinal bleeding after endosonographically guided transbronchial cryobiopsy (EBUS-TBKB) with suspected advanced lymphoma. The EBUS-TBKB is a new effective examination method in interventional pneumology for the diagnosis of diseases with mediastinal lymph node enlargement and intrathoracic tumors, with which large tissue cylinders in the mediastinum can be obtained. Due to the high diagnostic value of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for the clarification of lymphadenopathy, the examination should not be carried out as a routine application. Indications for a primary EBUS-TBKB arise when there is a suspicion of intrathoracic malignant lymphomas or other rare tumors in which extensive unfragmented tissue material is required for diagnosis. A rare complication that has not yet been described in the literature is a hematomediastinum, so that a careful risk assessment of possible bleeding complications should be carried out before intervention and the more invasive mediastinoscopy can be a safer examination method.

A new tool for bile duct tissue sampling: ex vivo clinical evaluation of intraductal cryobiopsy for cholangioscopy

Background and study aims  Indeterminate biliary strictures represent a major challenge in clinical diagnostics. Diagnostic yield of radiological, endoscopic imaging and histopathological diagnosis is insufficient. The cryobiopsy technique is a new method for tissue extraction already used in different clinical settings. The aim of this ex vivo clinical study was to investigate feasibility and tissue quality of cryobiopsy in the bile duct. Patients and methods  We included 14 patients who underwent pancreaticoduodenectomy. Bile duct samples were taken with either a new prototype cryoprobe or one of two forceps types. Results were analyzed for general feasibility, specimen size, histological assessability as well as representativity of retrieved tissue. Results  Feasibility of cholangioscopic forceps was poor compared to gastric biopsy forceps or cryobiopsy. Significantly larger tissue samples were obtained with cryobiopsy (5.6 ± 4.5 mm ² ) compared to gastric biopsy forceps (3.3 ± 5.1 mm ² , P  = 0.006). Furthermore, cryobiopsy was superior in histological assessment quality ( P  = 0.02) and concerning representativity ( P  = 0.03). Conclusions  Cryobiopsy in the bile duct is feasible and the quality of the obtained tissue is high. Further investigation of bile duct cryobiopsy in vivo is warranted.

Diagnostic value of a new cryoprobe for peripheral pulmonary lesions: a prospective study

Background

Cryobiopsy is an established technique that yields larger and higher-quality samples than does a forceps biopsy. However, it remains underutilised in the diagnosis of peripheral pulmonary lesions (PPLs), mainly because of difficulties in handling conventional cryoprobes. A recently introduced single-use cryoprobe with a smaller diameter and more flexibility than conventional ones may improve its diagnostic ability for PPLs. We conducted this prospective study to evaluate the feasibility of transbronchial cryobiopsy in the diagnoses of PPLs, using a new 1.7-mm cryoprobe.

Methods

The study included patients with PPLs less than 30 mm in diameter scheduled to undergo bronchoscopy. All the procedures were performed using a combination of virtual bronchoscopic navigation, radial endobronchial ultrasound (R-EBUS) and X-ray fluoroscopy, and all the samples were collected using the cryoprobe alone. Thereafter, we assessed the diagnostic outcomes and safety profiles.

Results

A total of 50 patients were enrolled and underwent cryobiopsy. The median lesion size was 20.8 mm (range, 8.2–29.6 mm), and the negative bronchus sign was seen in 34% of lesions. The diagnostic yield was 94% (95% confidence interval, 83.5–98.8%). A positive bronchus sign had a significantly higher diagnostic yield than did a negative bronchus sign (100% vs. 82.4%; P = 0.035). The yield was achieved regardless of other variables, including lesion size, location, and R-EBUS findings. The major complications were mild and moderate bleeding in 28% and 62% of patients, respectively. Pneumothorax was identified in one patient.

Conclusion

Transbronchial cryobiopsy using the new 1.7-mm cryoprobe is a feasible procedure that has the potential to increase the diagnostic accuracy for PPLs.

Trial registration

Japan Registry of Clinical Trials, jRCT1032200065. Registered July 8 2020, https://jrct.niph.go.jp/en-latest-detail/jRCT1032200065

Comparison between Image-Guided Transbronchial Cryobiopsies and Thoracoscopic Lung Biopsies in Canine Cadaver: A Pilot Study

Simple Summary

A definitive diagnosis for most pulmonary diseases is possible only through histopathological examination. The literature describes different methods of lung biopsy sampling depending on the case. However, for the diagnosis of diffuse interstitial pulmonary diseases and some peripheral neoplasms, the gold standard is represented by surgical lung biopsies. Given their invasiveness and the high percentage of risk for the patient, in most cases they are not carried out, resulting in a serious diagnostic gap. In human medicine, transbronchial lung cryobiopsies have been introduced as an alternative, which have shown high efficacy and reduced invasiveness. This study aims to evaluate the feasibility of the new technique in dogs by subjecting dog cadavers to pulmonary cryobiopsy and surgical lung biopsies, and to compare the samples obtained for histopathological quality. In total, 42 tissue samples were compared. Pulmonary cryobiopsies were smaller than surgical biopsies but with high levels of agreement upon histological evaluation. This study demonstrates the feasibility of the technique in dogs and the collection of specimens with size and histological features comparable to those from surgical biopsies.

Abstract

To date, the only method of sampling lung tissue with a high diagnostic yield is represented by surgical lung biopsies (SLB), which are highly invasive and have a high risk/benefit ratio. In humans, transbronchial lung cryobiopsies (TBLC) have recently been introduced, which are described to be less invasive and able to significantly increase diagnostic confidence in most patients with interstitial lung diseases. The aim of this study was to evaluate the feasibility and diagnostic yield of TBLC compared to SLB in small animals. A total of 21 pulmonary cryobiopsies under fluoroscopic and real-time CT fluoroscopic guidance and 21 video-assisted thoracoscopic surgery (VATS) lung biopsies were collected from three dog cadavers. Upon histological examination, cryobiopsy samples were smaller than VATS biopsies, but were still large enough to reach a specific diagnosis or to allow pattern recognition. Morphological features on TBLC and SLB were concordant in all cases. Cryobiopsy samples showed fewer artifacts and a higher percentage of alveolar tissue than VATS samples. TBLC is a feasible and useful alternative to SLB for lung histopathological examination in dogs. The effectiveness and reduced invasiveness of TBLC compared to SLB could represent many advantages in the diagnosis of diffuse lung diseases in small animals.

Improving the Quality of Human Upper Urinary Tract Specimens by Cryobiopsy

Objective

The quality of histopathological specimens obtained from the upper urinary tract with conventional flexible ureterorenoscopic biopsy needs to be improved. We investigated the feasibility and biopsy quality of specimens obtained by cryobiopsy, compared with standard ureterorenoscopic biopsy techniques in a human ex vivo model.

Materials and Methods

Human ureters obtained from nephrectomy specimens (N=12) were dissected and canulated with an ureteral access sheath. Ureterorenoscopic biopsies were randomly obtained from different sites of the renal pelvic caliceal system using different types of instruments. The performance of two newly developed flexible cryoprobes with outer diameters of 1.1 mm (CB11) and 0.9 mm (CB09) was compared with that of the biopsy forceps(FB) and Bigopsy®(BiG) and two different Dormia baskets N‐Gage (NG) and Zero‐Tip (ZT). We assessed the feasibility of the various biopsy techniques based on the number of biopsy attempts needed to obtain macroscopically discernible biopsies. The specimens were examined histopathologically for size, biopsy quality, presence of various artifact types, and representativeness.

Results

Biopsies taken with the cryoprobes showed a higher biopsy quality than biopsies taken with the comparative instruments. The CB11 provided significantly larger biopsies than forceps biopsies and also than biopsies with ZT. The CB09 was able to collect larger samples when compared with the FB and BiG biopsy forceps. There were no significant differences in artifact area, except for the CB11 cryoprobe compared with the NG. To clarify the results a subdivision of larger or smaller than 20% artifact area was performed. A significant difference was found between CB11 and the forceps biopsies, as well as between CB11 and NG and ZT in favor of the cryoprobe. The representation of the histopathological sample was also determined. Biopsies taken with CB11 were more representative compared with forceps biopsies BiG and FB and basket biopsies NG and ZT.

Conclusions

In a standardized comparative ex vivo setting, larger biopsies were obtained by using the cryobiopsy technique with the CB11 probe. Qualitatively, cryobiopsy specimens were overlaid by fewer artifacts and a higher biopsy quality was achieved in histopathologic examination compared with standard instrumentation. Further stepwise development will transfer the promising cryobiopsy technique into the clinical setting.

Transbronchial Cryobiopsy in Interstitial Lung Diseases: State-of-the-Art Review for the Interventional Pulmonologist

Interstitial lung diseases are a heterogenous group of disorders that are often difficult to diagnose precisely. Clinical, laboratory, radiographic, and histologic information may be needed to arrive at the correct diagnosis. The multidisciplinary discussion has been proven to be useful in this patient group. Transbronchial cryobiopsy has become a popular method for obtaining tissue samples. Over the course of the last decade, there has been a significant amount of research assessing the feasibility, safety, and diagnostic endpoints of transbronchial cryobiopsy in patients with interstitial lung disease. Data continues to mount to support its use, which has been reflected in guidelines and expert panel reports. Patient selection, procedural performance, and appropriate specimen handling are critical factors for success. A coordinated approach by pulmonologists with expertise in interstitial lung diseases, interventional pulmonologists, and thoracic pathologists is essential. In this evidence-based narrative review, we address transbronchial cryobiopsies from these three distinct perspectives. In addition, the current literature was used to address nine common procedural questions.

Combination of 1.1 mm flexible cryoprobe with conventional guide sheath and therapeutic bronchoscope in biopsy of apical upper lobe solitary pulmonary nodule

BACKGROUND

Lung cancer is frequently situated peripherally in the upper lobes of the lung. Acquiring adequate tissue from this difficult-to-reach area remains a challenge. Transbronchial cryobiopsy (TBCB) has the ability to acquire larger specimens, but the rigidity of the standard 1.9 mm and 2.4 mm cryoprobes frequently poses challenges when used with a guide sheath (GS). The novel 1.1 mm cryoprobe, being both smaller and more flexible, may address this limitation. We describe the usage of this 1.1 mm flexible cryoprobe with GS in the biopsy of solitary pulmonary nodules (SPN) in the apical segment of the upper lobe in two cases.

CASE REPORT

Both procedures were conducted with advanced airway under total intravenous anaesthesia. 2.6 mm GS was used in combination with a 2.2 mm rEBUS probe, using a therapeutic bronchoscope. Case 1 describes a SPN in the apical segment of the right upper lobe that was inconclusive by forceps biopsy due to GS displacement and inadequate biopsy depth. A steerable GS combined with the novel cryoprobe subsequently overcame this issue. Case 2 describes a SPN in the apical segment of the left upper lobe in which the standard cryoprobe failed to advance through the GS due to steep angulation. It also highlights with shorter activation time, the novel cryoprobe enable biopsied tissue to be retrieved through the GS while the bronchoscope-GS remains wedgend in the airway segment. There were no bleeding or pneumothorax complications in both cases, and histopathological examination confirmed adenocarcinoma of the lung.

CONCLUSION

The 1.1 mm flexible cryoprobe in combination with GS and therapeutic bronchoscope offers an option to acquire adequate tissue in difficult-to-reach regions in the lung such as the apical segment of upper lobes. Further prospective series to evaluate its performance and safety in SPN biopsy is highly anticipated.

Cryobiopsy in the Upper Urinary Tract: Preclinical Evaluation of a Novel Device

OBJECTIVE

To develop a novel device for cryobiopsy of the upper urinary tract (UUT) and to evaluate its feasibility in a standardized preclinical setting.

MATERIALS AND METHODS

Flexible cryoprobes (diameter 0.9 mm; cooling agent CO2) were developed and used to extract biopsies in porcine UUTs. Cryosamples obtained by ureterorenoscopy were systematically compared with biopsy specimens obtained with standard of care devices in terms of physical characteristics (deflection angle and irrigation flow rates) and histologic criteria (assessability).

RESULTS

Irrigation flow rates were significantly higher with introduced BIGopsy (2.8 ± 0.1) compared with standard forceps (0.94 ± 0.06; P < .001) and cryoprobe (1.1 ± 0.1; P < .001). Angular deflection was significantly reduced by the inserted cryoprobe (130.7° ± 1.2° vs 166.9° ± 1.1° [BIGopsy] or 161.4° ± 1.9° [standard forceps]; both P < .001). Significantly larger UUT tissue samples were obtained by the cryoprobe (mean specimen area 7.5 ± 2.5 vs 4.6 ± 2.5 mm² [BIGopsy] or 1.4 ± 1.4 mm² [standard forceps]; both P < .001). No crush artifacts were observed in cryosamples. Superior histologic assessability scores were achieved in samples obtained by the cryoprobe (mean 2.8 ± 0.8) and BIGopsy (2.3 ± 1.9) when compared with standard forceps (0.4 ± 0.9; P < .001).

CONCLUSION

Cryobiopsy in the UUT is feasible and represents a viable new option to improve the diagnostic accuracy of histopathologic evaluation. Larger and more representative tissue samples can be obtained using a cryoprobe and artifacts may be avoided. Further optimization of the probe will reduce possible restrictions of ureterorenoscopy handling when the device is inserted.

Interstitial lung disease: the diagnostic role of bronchoscopy

Interstitial lung diseases (ILDs) form one of the most fascinating fields in pulmonary medicine. They also pose one of the greatest challenges for accurate diagnosis and proper treatment. Even within the recommended and warranted multidisciplinary approach, differentiating between one disease and another may lead to frustration, especially when proper lung tissue is not available for adequate pathological review. A surgical lung biopsy (SLB) might render enough tissue for histopathology, but this could come at the expense of high morbidity and even mortality, as in the case of usual interstitial pneumonia (UIP). Could bronchoscopy and its various techniques offer a safer and higher yield alternative? Since the very late 19th century, efforts have been made to better examine the airways, obtain tissue and treat various conditions. This resulted in the successive emergence of bronchoalveolar lavage (BAL), endobronchial and transbronchial forceps biopsies, until recently when transbronchial cryobiopsy surfaced as a nascent technique with much promise. The use of endobronchial ultrasound revolutionized the diagnosis and staging of lung cancer, while adding to the yield of other conditions such as sarcoidosis. Ongoing research, efforts and studies have continuously scrutinized the roles of various techniques in the approach to ILDs. For example, BAL seems to serve mostly to eliminate infection as an etiology or a complicating factor in the acute worsening of a fibrotic lung disease, while a predominant cellular component might be diagnostic, such as eosinophilia in eosinophilic lung disease, or lymphocytosis in hypersensitivity pneumonitis (HP). On the other hand, endobronchial biopsy's (EBB) role appears limited to sarcoidosis. As for transbronchial biopsy by forceps, the small sample size and related artifact appear to be limiting factors in making an accurate diagnosis. Recently, however, the use of cryotherapy via employing a cryoprobe in obtaining transbronchial lung biopsies is unfolding into a refined interventional method which might transform indefinitely our approach to the pathological diagnosis of the various ILDs.

Transbronchial cryobiopsy for diffuse parenchymal lung disease: a state-of-the-art review of procedural techniques, current evidence, and future challenges

Transbronchial lung biopsy with a cryoprobe, or cryobiopsy, is a promising new bronchoscopic biopsy technique capable of obtaining larger and better-preserved samples than previously possible using traditional biopsy forceps. Over two dozen case series and several small randomized trials are now available describing experiences with this technique, largely for the diagnosis of diffuse parenchymal lung disease (DPLD), in which the reported diagnostic yield is typically 70% to 80%. Cryobiopsy technique varies widely between centers and this predominantly single center-based retrospective literature heterogeneously defines diagnostic yield and complications, limiting the degree to which this technique can be compared between centers or to surgical lung biopsy (SLB). This review explores the broad range of cryobiopsy techniques currently in use, their rationale, the current state of the literature, and suggestions for the direction of future study into this promising but unproven procedure.

Use of transbronchial cryobiopsy in the diagnosis of interstitial lung disease-a systematic review and cost analysis

BACKGROUND

Histological diagnosis by surgical lung biopsy for interstitial lung disease (ILD) is currently limited. Transbronchial cryobiopsy via flexible bronchoscope may this for more patients. The relative costs, diagnostic yields and safety of this approach and more traditional approaches have not been determined.

OBJECTIVES

To perform a systematic review and meta-analysis of transbronchial cryobiopsy, forceps transbronchial biopsy and video assisted (VATS) surgical lung biopsy assessing their relative diagnostic yields and safety. To perform a cost analysis to demonstrate any savings through change to the newer technique.

METHODS

We performed a systematic review of the literature using MEDLINE and EMBASE for all original articles on the diagnostic yield and safety of transbronchial cryobiopsy, forceps transbronchial biopsy and VATS-biopsy in ILD up to February 2016. Data were extracted on yield and complication rates, in addition to study characteristics. Theoretical cost analysis was performed from local institution financial data, 2015-16 reimbursement tariffs and results of the systematic review.

RESULTS

A meta-analysis of 11 investigations for transbronchial cryobiopsy, 11 for forceps transbronchial biopsy and 24 for VATS-biopsy revealed diagnostic yields of 84.4% (75.9-91.4%), 64.3% (52.6-75.1%) and 91.1% (84.9-95.7%), respectively. Pneumothorax occurred in 10% (5.4-16.1%) of transbronchial cryobiopsy procedures, moderate bleeding in 20.99% (5.6-42.8%), with three deaths reported. Surgical mortality was 2.3% (1.3-3.6%). Cost analysis demonstrated potential savings of £210 per patient in the first year and £647 in subsequent years.

CONCLUSIONS

Transbronchial cryobiopsy represents a potentially cost-saving approach to improve histological diagnosis in ILD, however is accompanied by a significant risk of moderate bleeding.

Transbronchial cryobiopsy in interstitial lung disease: experience in 106 cases - how to do it

Transbronchial biopsy using forceps (TBB) is the first diagnostic technique performed on patients with interstitial lung disease (ILD). However, the small size of the samples and the presence of artefacts in the tissue obtained make the yield variable. Our objectives were 1) to attempt to reproduce transbronchial cryobiopsy under the same conditions with which we performed conventional TBB, that is, in the bronchoscopy unit without intubating the patient and without fluoroscopy or general anaesthesia; 2) to describe the method used for its execution; and 3) to analyse the diagnostic yield and its complications. We carried out a prospective study that included 106 patients with clinical and radiological features suggestive of ILD who underwent cryo-transbronchial lung biopsy (cryo-TBB) under moderate sedation without endotracheal intubation, general anaesthesia or use of fluoroscopy. We performed the procedure using two flexible bronchoscopes connected to two video processors, which we alternated until obtaining the number of desired samples. A definitive diagnosis was obtained in 91 patients (86%). As for complications, there were five pneumothoraces (4.7%) and in no case was there severe haemorrhage or exacerbation of the underlying interstitial disease. Cryo-TBB following our method is a minimally invasive, rapid, safe and economic technique that can be performed in a bronchoscopy suite under moderate sedation without the need for intubating the patient or using fluoroscopy and without requiring general anaesthesia.