Perioperative Echocardiographic Examination for Ventricular Assist Device Implantation

Abstract

Ventricular assist devices (VADs) are systems for mechanical circulatory support of the patient with severe heart failure. Perioperative transesophageal echocardiography is a major component of patient management, and important for surgical and anesthetic decision making. In this review we present the rationale and available data for a comprehensive echocardiographic assessment of patients receiving a VAD. In addition to the standard examination, device-specific pre-, intra-, and postoperative considerations are essential to the echocardiographic evaluation. These include: (a) the pre-VAD insertion examination of the heart and large vessels to exclude significant aortic regurgitation, tricuspid regurgitation, mitral stenosis, patent foramen ovale, or other cardiac abnormality that could lead to right-to-left shunt after left VAD placement, intracardiac thrombi, ventricular scars, pulmonic regurgitation, pulmonary hypertension, pulmonary embolism, and atherosclerotic disease in the ascending aorta; and to assess right ventricular function; and (b) the post-VAD insertion examination of the device and reassessment of the heart and large vessels. The examination of the device aims to confirm completeness of device and heart deairing, cannulas alignment and patency, and competency of device valves using two-dimensional, and color, continuous and pulsed wave Doppler modalities. The goal for the heart examination after implantation should be to exclude aortic regurgitation, or an uncovered right-to-left shunt; and to assess right ventricular function, left ventricular unloading, and the effect of device settings on global heart function. The variety of VAD models with different basic and operation principles requires specific echocardiographic assessment targeted to the characteristics of the implanted device.

Echocardiographic Variables After Left Ventricular Assist Device Implantation Associated With Adverse Outcome

“…It is frequently used to evaluate native heart and LVAD function and for troubleshooting possible device malfunctions. [7][8][9][10][11] Although continuous LVAD therapy has been in clinical use for a number of years, a comprehensive analysis of post operative echocardiographic variables associated with failure of therapy has not been reported to date. Because LVAD therapy is supposed to improve cardiac output and unload the left cardiac chambers, we postulated that variables estimating total or LVAD output, as well as those estimating the efficiency of left ventricular or left atrial unloading may be associated with failure to improve heart failure symptoms after LVAD surgery.…”

Left ventricular assist device exchange: the Toronto General Hospital experience

“…Echocardiography cannot evaluate the pump directly; however, it may be beneficial to detect indirect evidence of thrombosis, such as left ventricular dilatation, consistent opening of the aortic valve during systole despite high pump speeds and a shift of the interventricular septum to the right. 15 As noted previously, we routinely performed echocardiography and ramp studies in our subacute presenting patients with suspected thrombosis.…”

Echocardiographic Evaluation of Ventricular Assist Devices

“…Adequate right ventricular function is not only required for adequate filling and function of an LVAD but RV dysfunction may occur following implantation of an LVAD. Up to one third of patients that have an LVAD may also require an RVAD (19)(20)(21). However, the incidence of RV dysfunction following LVAD insertion may be lower in the newer continuous flow pumps as compared to pulsatile pumps (22).…”

“…Aortic stenosis is usually not of such clinical significance compared to aortic regurgitation. However in continuous flow devices, depending upon the configuration, aortic stenosis may limit forward flow and may need surgical replacement at the time of VAD insertion (19). Tricuspid regurgitation is a relatively common condition in patients being assessed for mechanical support.…”

“…The decision to correct tricuspid regurgitation at the time of VAD insertion is a complex one. If significant tricuspid regurgitation is present and it is expected that improvement (via annuloplasty or repair but not replacement due to the risk of valve thrombosis) of this would result in improved RV function, then intervention on the tricuspid valve may be warranted (19,28).…”