Figure 3.1 From left to right: Endoscope, radial EUS, linear EUS, bronchoscope, and linear EBUS.

Patient Preparation

Routine preprocedure screening is not recommended; instead, focused history, examination, and testing based on the clinical suspicion is advised. Pregnancy test may be indicated in women in childbearing age. Although endoscopy is not contraindicated in pregnancy, adequate shielding should be utilized when fluoroscopy is used, and adequate preparation should be made in cases when general anesthesia may be required.

Patients should fast at least 2 hours after consuming clear liquids and 6 hours after consuming light meals before administration of sedation. They are advised to continue their cardiac, antihypertensive, pulmonary, antiepileptic, psychiatric drugs, and oral birth control medication. Oral hypoglycemic agents should be withheld on the morning of the procedure until resumption of normal diet. Pills can be taken with small amount of water. Patients on insulin should be advised to take half of their usual morning dose.

Anticoagulation should be managed based on the risk on the thrombotic risk and the estimated risk of bleeding. The anticoagulant is indicated as prophylaxis against development of new thrombi or embolism (mechanical valves and atrial fibrillation) and as treatment of thrombus-related problems (deep vein thrombosis (DVT) and pulmonary embolus (PE)).

Warfarin should be withheld 5 days before elective procedures. Rapid reversal may be achieved by withholding warfarin and administering vitamin K or if quick reversal is indicated, fresh frozen plasma or prothrombin complex should be administered. Bridging with enoxaparin or heparin is indicated if the thrombotic risk is high (e.g., mechanical valve). Warfarin can be restarted 12 to 24 hours after the procedure with or without bridging. Full anticoagulant effect will be achieved in 4 to 6 days.

Dabigatran should be stopped 1 to 2 days before the procedure if the creatinine clearance is more than 50 mL/min and 3 to 5 days if the creatinine clearance is less than 50 mL/min. The peak anticoagulant effect is achieved 2 to 3 hours after administration. Rivaroxaban and apixaban have elimination half-life and rapid onset of action similar to dabigatran but are less dependent on renal function.

Unfractionated heparin should be stopped 4 to 5 hours before the procedure. The last dose of low-molecular-weight heparin should be 24 hours before the procedure. The anticoagulation effect starts 1 hour after administration and peaks in 3 to 5 hours.

Antiplatelet agents such as clopidogrel and aspirin–dipyridamole (Aggrenox) should be held 7 days before the planned procedure. Clopidogrel is mandatory for 6 weeks after bare-metal stent placement, 3 to 6 months after myocardial infarction, and at least 12 months after drug-eluting stent. Aspirin alone does not increase significantly the risk of bleeding and does not need to be stopped.

Prophylactic antibiotics are not recommended for patients undergoing bronchoscopy, EBUS-, and EUS-guided lung mediastinal and hilar biopsy despite minimal risk of bacteremia. Prophylactic antibiotics are indicated in patients undergoing EUS– fine needle aspiration (FNA) of cystic lesions along the GI tract, including the mediastinum.

Patients undergoing endoscopic procedures with moderate and deep sedation must have continuous monitoring before, during, and after the administration of sedatives. A combination of opioid and benzodiazepine is usually used for moderate sedation. Topical anesthetics like lidocaine, benzocaine, and tetracaine are used for pharyngeal anesthesia, and topical anesthesia of the vocal cords and the airways. Topical anesthetics are associated with serious adverse effects such as aspiration, anaphylactoid reactions, and methemoglobinemia. Deep sedation utilizing propofol alone or propofol in combination with other sedative hypnotics may be used but necessitates a dedicated person with no other procedure-related responsibilities for observation and monitoring of the patient. Furthermore there is a requirement for specific training and credentialing for the personnel involved in medication administration and patient monitoring. General anesthesia or assistance of an anesthesia specialist should be considered in the following scenarios: ASA physical class III, IV, and V; complex endoscopic procedures, prior adverse reactions to sedation and anesthesia, intolerance to standard medication utilized for moderate sedation, inadequate response to moderate sedation, and patients with anatomic variations predictive of increased risk for airway obstruction and difficult intubation.

INDICATIONS

EBUS and EUS are indicated in diagnostic and therapeutic procedures. Diagnostic procedures include: Staging of nonsmall lung cancer, staging of esophageal cancer, diagnostic evaluation of mediastinal, pulmonary, and endobronchial lesions. Echoendoscopes may also be utilized to guide photodynamic therapy, brachytherapy, and airway recanalization.

Echoendoscopy is a great tool for the diagnosis and staging of lung cancer. EBUS and EUS may be utilized in the determination of all three characteristics—local tumor (T), lymph node metastasis (N), and distant metastasis (M) in the seventh edition of the TNM staging system. The laminar structure of the airway wall and invasion of the airway wall by tumor can be visualized with EBUS. EBUS can also be helpful in differentiating infiltration of the airway wall from external compression with sensitivity, specificity, and accuracy higher than chest computed tomography (CT). It may be used to measure the distance between the carina and the proximal end of tumors involving the bronchial wall. Tumor invasion of the mediastinum can be assessed with EUS. This modality is highly accurate in ruling out mediastinal invasion by lung cancer and in diagnosing great vessels involvement but has high false-positive rate for mediastinal fat involvement. Mediastinal lymph node involvement should be assessed in patients with known or suspected lung cancer who have either one of the following clinical scenarios: Normal mediastinum (by CT and positron emission tomography (PET)) and a central tumor, discrete mediastinal lymph node involvement on CT or PET uptake, and PET activity in a mediastinal lymph node and normal appearing nodes by CT. Utilizing needle technique (EBUS and/or EUS) for mediastinal lymph node staging is recommended over surgical staging as a best first test in patients with high suspicion of N2,3 involvement. Endoscopic needle techniques are also useful for detection of metastases to the liver, adrenal glands, and the celiac lymph nodes. The combination of EBUS and EUS was complementary with pooled median sensitivity of 91% and specificity of 100% in a population with 33% prevalence of cancer. The median negative predictive value (NPV) was 96%.

Echoendoscopy plays a major role in the locoregional staging of esophageal cancer and has essentially replaced chest CT as the locoregional staging modality of choice. Nevertheless, chest CT and PET are used for evaluation of distant metastatic disease. Although the overall accuracy of EUS for tumor (T) and node (N) staging is up to 90%, the accuracy may be lower in patients with early superficial esophageal cancer—67% for T1 lesions. EUS identifies the depth of invasion and defines the T staging based on the involvement of the mucosa (T1), muscularis propria (T2), adventitia (T3), and surrounding structures (T4). The measurement of the maximal thickness of the esophageal mass may help in predicting the extraesophageal extension. EUS may overstage esophageal cancer when invasion of the mediastinum is detected since the tumor may not be reliably differentiated from the surrounding inflammation. EUS combined with FNA carries high sensitivity, specificity, and accuracy for detection of metastatic disease in the lymph nodes. The number of the involved lymph nodes is utilized in the nodal staging of esophageal tumors. Although celiac nodal metastases are considered regional nodal disease in the 2010 TNM staging system, their presence may portend poor prognosis. EUS may also be utilized in the detection of metastatic disease in the adrenal glands, liver, peritoneum, and the lung. Restaging of esophageal cancer after neoadjuvant chemoradiotherapy remains a contentious issue. Two recent studies suggest that EUS may not be useful in the evaluation of the response after neoadjuvant treatment.

EBUS and EUS may be utilized for mediastinal staging of extrathoracic malignancies like breast, kidney, and colon. Also, they provide an alternative approach to transbronchial biopsies and transthoracic needle aspiration for evaluation of peripheral lung masses.

EUS-guided biopsy is helpful in diagnosing lymphomas. The sensitivity of EBUS– trans-bronchial needle aspiration (TBNA) varies between 57% and 90.9% with specificity of 100%. In a recent study by Moonim et al. new diagnosis of lymphoma was made correctly in 88%. The sensitivity for relapse was 100%. The sensitivity of EBUS–TBNA in subtyping lymphomas into high-grade non-Hodgkin, low-grade non-Hodgkin, and Hodgkin lymphomas were 90%, 100%, and 79%, respectively. EBUS–TBNA diagnosis was adequate for clinical management in 84%. EUS-guided biopsy correctly diagnosed 79% of lymphomas and subclassification was successful in 67% in a study by Ribeiro et al.

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