Discussion
LVADs have various consequences in the native heart including the development of AI. The incidence of new-onset AI increases with support duration, with 10% of patients developing at least moderate AI within 6 months of support and 25% to 30% of patients developing AI within the first year of implantation (2). If left untreated, recirculation syndrome can occur, causing worsening heart failure necessitating aortic valve surgical intervention or urgent cardiac transplantation in 50% of patients within 6 months of developing significant AI (3). While ICE has been a standard imaging modality for interventional and electrophysiological procedures, few studies report its utility in the management of LVADs (4,5).
Traditional TTE methods can underestimate the severity of AI in patients with LVADs, and poor acoustic windows can limit its effectiveness. Traditional TTE indices to grade the severity of AI underestimated AI in 33% of cases, especially in cases with less than moderate regurgitation (6,7). While current guidelines to evaluate AI have been previously validated, they do not extend to patients with continuous flow LVADs (CFLVAD) at present. Since current TTE parameters are suboptimal in grading AI severity in patients with LVADs, the clinical significance of AI in this population can be missed, ultimately portending a poor long-term prognosis.
Transesophageal echocardiography (TEE) is an alternative, but anesthesia requirements can be prohibitive. Anesthesia can also underestimate the severity of AI. General anesthesia lowers systemic vascular resistance so that the reduced afterload increases forward flow through the LVAD and reduces AI.
Given the limitations of TTE and TEE, we propose that ICE can be considered under the following circumstances in the setting of a CFLVAD: TTE assessment is limited due to poor acoustic windows, demonstrates probable AI, or does not demonstrate AI but clinical suspicion for AI remains high; the patient is unable to tolerate general anesthesia, which is needed for TEE; the patient needs a ramp study that cannot be adequately performed with TTE or TEE.