What is the role of Endobronchial Ultrasound (EBUS) in cardiothoracic surgery evaluation for lung biopsy?

Endobronchial Ultrasound (EBUS) in Cardiothoracic Surgery Evaluation for Lung Biopsy

Endobronchial ultrasound (EBUS) is a minimally invasive technology that allows real-time visualization of structures adjacent to the airways during bronchoscopy and should be used as the first-line procedure for diagnosis and staging of suspected lung cancer with mediastinal or hilar involvement. 1

What is EBUS?

EBUS is a diagnostic technique that incorporates ultrasound technology into bronchoscopy, allowing visualization of the tracheobronchial wall and surrounding structures. There are two main types:

• Linear EBUS: Incorporates an ultrasound transducer into the tip of a specially-designed flexible bronchoscope, allowing real-time guidance for transbronchial needle aspiration (TBNA) of lymph nodes and parabronchial masses 1

• Radial EBUS: Uses a miniaturized ultrasound probe (2.8-3.2 mm) with balloon-tipped transducers that can be inserted through the working channel of conventional bronchoscopes to guide sampling of peripheral lung nodules and masses 1

Clinical Applications in Cardiothoracic Surgery Evaluation

EBUS has several important applications in the cardiothoracic surgery evaluation process:

• Mediastinal lymph node staging in lung cancer: EBUS-TBNA has an overall median sensitivity of 89% and a negative predictive value of 91%, making it superior to conventional staging methods 1, 2

• Diagnosis of undiagnosed intrathoracic lesions: EBUS can diagnose approximately 55% of cases that remain undiagnosed after conventional CT and bronchoscopy 3

• Evaluation of peripheral lung lesions: When the EBUS probe can be placed inside a peripheral lesion, sensitivity and specificity for cancer diagnosis can reach 100% 4

• Assessment of mediastinal structures: EBUS can identify and localize mediastinal tumors and other structures adjacent to the airways 1

• Evaluation of tumor invasion depth: EBUS can stage the depth of tumor invasion in the bronchial wall 1

Technical Aspects of EBUS-TBNA

For optimal results during EBUS-TBNA procedures:

• Sedation: Either moderate or deep sedation is acceptable 1

• Needle selection: 21-gauge or 22-gauge needles are recommended over 19-gauge needles for suspected malignant disease 1

• Number of needle passes: A minimum of 3 separate needle passes should be performed per sampling site without rapid on-site evaluation (ROSE); 4 or more passes are strongly recommended for suspected malignant disease 1

• Specimen collection: Tissue sampling may be performed either with or without suction 1

• Rapid on-site evaluation (ROSE): While not required, ROSE is suggested to improve diagnostic yield 1

• Additional sampling: For suspected non-small cell lung cancer, additional samples beyond those needed for diagnosis should be obtained for molecular analysis 1

Advantages of EBUS Over Other Methods

• Minimally invasive: EBUS is significantly less invasive than mediastinoscopy or thoracotomy 5

• Outpatient procedure: Can be performed on an outpatient basis with minimal recovery time 3

• Safety profile: Very low complication rate compared to surgical alternatives 1, 3

• Cost-effectiveness: Reduces the need for more expensive and morbid invasive procedures 5

• Diagnostic accuracy: High sensitivity and specificity for both malignant and benign conditions 2

Special Considerations for Non-Malignant Conditions

EBUS-TBNA is also valuable for diagnosing non-malignant conditions:

• Sarcoidosis: EBUS-TBNA is recommended for diagnosis of suspected sarcoidosis with mediastinal/hilar adenopathy 1

• Tuberculosis: EBUS-TBNA is recommended for diagnosis of suspected tuberculosis with mediastinal/hilar adenopathy requiring lymph node sampling 1

• Lymphoma: EBUS-TBNA is an acceptable initial, minimally invasive diagnostic test for suspected lymphoma 1

Training Requirements

• Experience level: EBUS should be performed by or under the supervision of an experienced bronchoscopist 1

• Training recommendations: Trainees should participate in approximately 40 supervised procedures and become familiar with ultrasonic imaging 1

• Simulation training: Low or high-fidelity simulation should be incorporated in training 1

• Skills assessment: Validated EBUS skills assessment tests should be used to objectively evaluate operator competency 1

Conclusion

EBUS represents a significant advancement in bronchoscopic techniques that has transformed the diagnostic approach to mediastinal and hilar diseases. Its high diagnostic accuracy, minimal invasiveness, and excellent safety profile make it an essential tool in the evaluation of patients requiring lung biopsy in the cardiothoracic surgery setting.