Echocardiographic Predictors of Adverse Outcomes After Continuous Left Ventricular Assist Device Implantation

Study Questions:

What are the echocardiographic predictors of adverse outcomes in patients with severe congestive heart failure (CHF) implanted with a continuous flow left ventricular assist device (LVAD)?

Methods:

Echocardiographic data were available from 83 patients who underwent an LVAD implantation (HeartMate II, Thoratec Corporation). Patients were followed for in-hospital mortality (30 days) and the combined endpoint of in-hospital mortality and acute right ventricular (RV) dysfunction, as well as long-term mortality. Echocardiographic parameters included LV internal dimensions and assessment of function, assessment of mitral and tricuspid regurgitation severity, and parameters of RV function including duration of tricuspid regurgitation corrected for heart rate (TRDc).

Results:

Short-term endpoints included eight deaths before discharge (9.6%) and acute RV dysfunction in 15 patients. A relatively small LV internal dimension (<63 mm) was predictive of in-hospital mortality (odds ratio [OR], 0.9; p = 0.04) or the combined cardiac endpoint (OR, 0.89; p < 0.001). Short TRDc predicted in-hospital mortality (OR, 0.85; p = 0.01) and the combined cardiac event endpoint (OR, 0.83; p < 0.0001). On multivariable analysis, prediction of the 30-day compound adverse outcome was improved by addition of echocardiographic variables to more traditional hemodynamic and clinical scores. Long-term survival was also predicted by TRDc with a risk ratio of 0.88 for cardiac-related death (p = 0.03).

Conclusions:

Presence of either a relatively small (<63 mm) LV cavity or equalization of RV and right atrial pressure as manifest by short TRDc on echocardiography were associated with worse 30-day mortality and morbidity, and these parameters were additive to traditionally used clinical scores.

Perspective:

This study examines a number of echocardiographic and clinical variables in a very complex patient population, that is patients with end-stage heart disease requiring LVAD support, either as destination or bridge therapy. It has long been recognized that RV function may be the limiting factor in how well these patients, who preoperatively have predominate LV failure symptoms, become the limiting factor once an LVAD has provided replacement therapy for LV dysfunction. The link between a relatively small LV cavity (<63 mm) and short-term mortality is unclear, and the authors’ suggestion that the smaller LV may set the patient up for a 'suction event' in which the LVAD, by decompressing the LV to an excess degree, results in septal shift and worsening RV function is one plausible explanation. Of note, the survival curves suggest the relatively small LV has an impact on adverse events only in the first 3 months after which a small LV appeared not to confer further excess mortality. RV dysfunction is often concurrent with severe LV dysfunction and may become the limiting factor in preload for the LVAD, thereby compromising its effectiveness. RV dysfunction has been previously described as a marker of an adverse outcome, both short- and long-term in patients with congestive heart failure including those undergoing LVAD therapy. Of note in this study, evidence of significant RV dysfunction, as manifest by relatively short TRDc, had both a short- and long-term effect on outcome, which was noticeable immediately after implant and continued to exert an adverse influence over the course of follow-up with these patients.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Acute Heart Failure, Mechanical Circulatory Support , Echocardiography/Ultrasound

Keywords: Ventricular Function, Right, Follow-Up Studies, Hospital Mortality, Atrial Pressure, Heart-Assist Devices, Tricuspid Valve Insufficiency, Heart Failure, Ventricular Dysfunction, Right, Echocardiography


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