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.