Transcatheter biopsy for intracardiac masses

Clinical considerations

First, there must be concrete clinical benefit in performing biopsy of an ICM to establish histopathologic diagnosis. The mass must remain undiagnosed despite noninvasive study. Simple entities like endocarditic vegetations and appendage thrombus can be diagnosed with reasonable certainty and treated with standard therapies after echocardiographic diagnosis—such lesions should not be biopsied unless the clinical picture is unclear. The specific benefit of histopathologic diagnosis is either an increased accuracy of molecular targeting, such as ligand-specific chemotherapy for cancer metastases, or the obviation of cardiac surgery for compressive lesions that can be resolved without excision, such as primary cardiac lymphoma. There is also a role for establishing a histopathologic diagnosis to guide an informed transition to palliative care for patients with incurable pathology.

Technical considerations

Second, there must be a focal ICM in the heart accessible by the intravascular route or through the anterior chest wall. The lesion should be continuously visible by echocardiography, either TTE or TEE, which is critical for procedural guidance. Lesion size must be sufficient to allow engagement by the biopsy equipment, but there is no concrete size at which biopsy must be abandoned, and lesion morphology will also affect the likely success of a biopsy. Masses that are sessile and circumscribed are more likely to be engaged with biopsy equipment compared with lesions that are pedunculated and filamentous. Masses that are highly mobile are more difficult to biopsy. The location of the lesion in the cardiovascular system should be considered. As with any structural procedure, relational anatomy will dictate expected complications. Lesion proximity to structures such as the sinoatrial node, AV node, His bundle, and prosthetic or native valve leaflets should raise concern. Right-sided masses are more accessible and carry a lower risk of systemic thromboembolism compared with left-sided masses. Mass lesions located on the interatrial and interventricular septum present a lower risk of cardiac perforation and pericardial tamponade compared with free wall lesions.

Biopsy equipment

Medical tools to remotely retrieve cardiac tissue include the standard endomyocardial bioptome (Jaws, Argon Medical, Frisco TX), hepatic side-cutting needles (BX Needle, Cook Medical, Bloomington, IN), and gastrointestinal biopsy forceps (EndoJaw, Olympus Medical, Tokyo, JP) ( Fig. 31.1 ). All devices are compatible with an 8F hemostatic sheath. A complex avulsion approach with a combination of a loop snare to electrosurgically sever the base of a mass (Gooseneck, Medtronic, Minneapolis, MN) and a trileaflet snare (EN Snare, Merit Medical, South Jordan, UT) to retrieve the mass can be considered in sites where embolic potential is limited. The sheath size should be large enough to accommodate the size of the mass in order to extract it. We have performed a single biopsy of an anterior cardiac mass via the percutaneous transthoracic approach using a Jamshidi bone marrow biopsy needle (Beckton Dickinson, Franklin Lakes, NJ), but this is a high-risk procedure and may not be replicable at other centers.

Biopsy equipment selection should be tailored to the lesion. For masses that are thought to be relatively soft based on imaging characteristics, the endomyocardial bioptome allows for targeted lesion sampling without damage to surrounding structures. In cases where the mass is thought to be relatively hard, contained in a fibrous pellicle, covered with chronic thrombus, and has enough noncritical surrounding tissue to allow for biopsy-targeting errors, a side-cutting needle or EndoJaw biopsy forceps can be considered.

The Quick-Core side-cutting needles are designed for transjugular hepatic and renal biopsies in coagulopathic patients. The needle throw is 2 cm, and one should make sure that there is enough mass length to accommodate the full length of the needle without penetration into other structures behind it. Operators should note that sheath length may be a limiting factor when these needles are used. The transjugular hepatic biopsy needle has a total length of 50 cm. It has a sharp tip that will not traverse standard hemostatic sheaths. A 7F metal introducer tube is included and must be used to avoid piercing sheaths with the needle while inserting it into the body. The transjugular renal biopsy needle has a length of 70 cm. The added length may be advantageous for antegrade transseptal or retrograde aortic procedures. Although it is also supplied with a 7F metal introducer, it has a blunt tip that can be directly introduced into hemostatic sheaths without risk of traversing the sheath wall. The main reason to use a liver biopsy needle, other than anatomic accessibility, is that ICMs, particularly tumors, are often encapsulated, and the standard jaws of our bioptomes will not penetrate this type of lesion.

The EndoJaw biopsy forceps are designed for remote biopsy of gastrointestinal lesions through endoscope lumens. The standard version has a 2-mm diameter and requires an 8F sheath. It has three traumatic teeth on either side and may avulse a large portion of the mass because of the force with which tissue can be gripped. Masses located close to valves should be avoided with this approach. Serial use of a variety of biopsy devices may allow sampling at different mass depths. It is unknown if this increases diagnostic yield.

Access sizing

Sheath size is dependent on the biopsy equipment chosen. We recommend the use of a long, braided straight or curved sheath to avoid having to steer through the femoral venous vasculature with the biopsy instrument. Embedding the sheath into the mass allows rapid repeat sampling with the biopsy instrument without have to navigate each time. A steerable sheath (Agilis NXT, Abbott Vascular, St. Paul, MN) can be useful in tortuous anatomies or angulated mass locations. A combination telescoping technique using a standard vascular sheath and a large-bore coronary guiding catheter might be an alternative if a steerable sheath is not readily available. Care should be taken to ensure that the selected biopsy equipment will fit through the selected sheath before starting the procedure. Suture-mediated closure devices (Perclose Proglide, Abbott Vascular, St. Paul, MN) can be considered for hemostatic closure when large-bore sheaths are used. In cases where intracardiac echocardiogram (ICE) is required for mass visualization and biopsy guidance, a separate vascular access sheath should be inserted.