Monitoring of Aortic Valve Opening and Systolic Aortic Insufficiency in Optimization of Continuous-Flow Left Ventricular Assist Device Settings

Can Intraoperative Transesophageal Echocardiography Predict Postoperative Aortic Insufficiency in Patients Receiving Implantable Left Ventricular Assist Devices?

OBJECTIVE

Aortic insufficiency (AI) develops in 25% of patients after left ventricular assist device (LVAD) insertion. The objective of this study was to evaluate the occurrence of new-onset AI upon initiation of cardiopulmonary bypass (CPB) required for LVAD insertion and the potential ability of this new-onset AI to predict development of post-LVAD insertion AI.

DESIGN

Forty-one patients undergoing LVAD insertion were studied. Intraoperative transesophageal echocardiography (TEE) evaluation was performed at baseline (post-induction, pre-sternotomy), 5 minutes after CPB initiation, and post-chest closure. Patients were followed up postoperatively for development of AI.

SETTING

Single university hospital.

PARTICIPANTS

Patients undergoing elective LVAD insertion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

At baseline, 35 patients exhibited none-trace AI, 4 exhibited mild AI, 2 exhibited moderate AI, and none exhibited severe AI. After initiation of CPB, 34 patients exhibited no change in degree of AI yet 7 exhibited an increase in AI severity. However, all 7 patients exhibited no change in degree of AI at chest closure and one exhibited a decrease in AI severity. Four patients developed at least moderate AI during the postoperative period (range 3-8 months). However, only one of these patients exhibited an increase in AI severity after initiation of CPB for LVAD insertion. No significant changes in aortic root measurements were observed during the entire intraoperative period (within patients nor between patients with/without development of at least moderate postoperative AI).

CONCLUSIONS

One in 5 patients undergoing LVAD insertion will demonstrate an increase in AI severity at CPB initiation without changes in aortic root measurements. None of the information obtained from intraoperative TEE seemed to predict development of at least moderate postoperative AI.

Does CircuLite Synergy assist device as partial ventricular support have a place in modern management of advanced heart failure?

The discrepancy between the number of patients on the waiting list and available donor hearts has led to the successful development of left ventricular assist devices (LVAD) as a bridge to transplantation. The conventional LVADs are designed to provide full hemodynamic support for the end-stage failing heart. However, full-support LVAD implantation requires major surgery, sternotomy and cardiopulmonary bypass in majority of cases. The Synergy Micro-pump is the smallest implantable LVAD and provides partial flow support up to 3 l/min. It was shown that early intervention with this device can provide substantial benefits to patients with severe heart failure not yet sick enough for a full-support LVAD. Due the small dimensions it can be implanted without cardiopulmonary bypass or a sternotomy. The purpose of this article is to review the clinical use of the Synergy Micro-pump as partial hemodynamic support.

Management of patients with implanted ventricular assist devices for noncardiac surgery: a clinical review

While originally primarily used as bridge to cardiac transplantation and bridge to recovery, more commonly ventricular assist devices (VADs) are being inserted as destination therapy. These patients are being discharged from transplant and mechanical assist centers, living as outpatients, and thus the pool of community-dwelling patients with VADs continues to expand. Not infrequently they present for surgical procedures either directly related to the device itself or more often incidental to the fact that they have a VAD. This scenario may be more common in patients with VADs placed for destination therapy because these patients tend to be older and have more comorbidities and are living longer with their device. Thus, it is important for all anesthesiologists to be aware of the special anesthesia needs of patients with VADs requiring noncardiac surgery.

Modeling aortic valve closure under the action of a ventricular assist device

The support of a failing heart with pump devices has been an essential element in cardiac health care for several decades. It is therefore important to understand the left ventricular response to the pumping action of these devices when connected to the native heart. Furthermore, monitoring of aortic valve opening and closure is important in avoiding valve stenosis and thrombogenesis during pump support. This paper reports the first steps in simulating the effects of outlet pump pressure on aortic valve closure of the heart assisted by an implantable blood pump. A two-dimensional fluid structure interaction aortic valve model is presented with blood flow in left ventricular chamber using the Arbitrary Lagrangian-Eulerian Finite Element Method formulation to predict the AV closure during outflow of blood from the left ventricle into the left ventricular assist device (LVAD).