Anesthesia for left ventricular assist device placement

Anaesthesia for Implantation of the Jarvik 2000 Flowmaker® LVAD

The Jarvik 2000 Flowmaker® is an intraventricular continuous axial flow left ventricular assist device. We describe the anaesthetic management and considerations for five patients with end-stage heart failure who underwent implantation of the Jarvik 2000 Flowmaker® as a bridge to transplantation or as destination therapy.

Anesthetic Management for Left Ventricular Assist Device Implantation Through Left Thoracotomy: Evaluation of On-Pump Versus Off-Pump

BACKGROUND

Ventricular assist devices (VADs) are alternative approaches to medical treatment in patients with acute or chronic heart failure. The goal of this study was to compare an anesthetic approach in patients undergoing implantation of a VAD with (on-pump) or without (off-pump) cardiopulmonary bypass (CPB) through left thoracotomy.

METHODS

A total of 32 patients were divided into 2 groups: on-pump (group 1) and off-pump (group 2). A standard anesthesia protocol was used in all patients. Baseline characteristics of the patients, intraoperative hemodynamic and respiratory variables, anesthetic agents and vasoactive drugs administered, the amount of blood products, extubation, length of hospital stay and intensive care unit stay, and postoperative complications were recorded.

RESULTS

Patients' mean age was 54.7 ± 13.3 years (range, 18-74 years). Eighteen patients underwent surgery with CPB. Demographic data of the patients, preoperative characteristics, intraoperative use of blood products, intraoperative complications, and anesthetic drugs used were similar between groups (P > .05). The duration of surgery (219 ± 23 vs 273 ± 56 minutes) and anesthesia (274 ± 38 vs 323 ± 57 minutes) were shorter in group 2; there was no difference between the 2 groups in terms of mechanical ventilation time, length of stay in the intensive care unit, and length of hospital stay. There was no decrease in postoperative oxygen parameters and an increase in patient lactate levels with the use of CPB. The use of fresh frozen plasma and platelet suspension in the postoperative period was significantly higher in group 1 (P < .05). The rate of complications and mortality rate were comparable between the 2 groups (P > .05).

CONCLUSIONS

Our study results show that the use of CPB during VAD implantation via left thoracotomy increases operation time and use of blood products, while causing no change in the rate of complications.

Ventricular Assist Devices and Anesthesia

Ventricular assist devices (VADs) have revolutionized longterm care for patients with congestive heart failure. These patients represent about 1% of the adults in the United States, considering that heart failure is a contributing factor in more than 250,000 deaths annually. It has been estimated that about 60,000 patients per year in the United States could benefit from heart transplantation or long-term mechanical support. Because of the short supply of donor hearts for transplant, assist devices have become of great value. At least four assist devices are clinically available, and two other devices are being investigated. Because cardiopulmonary bypass is required for implantation of these devices, anesthetizing these critically compromised patients requires extensive monitoring, skillful anesthetic management, and expert postoperative care.

Effects of Sevoflurane and Propofol on Organ Blood Flow in Left Ventricular Assist Devices in Pigs

The aim of this study was to assess the effect of sevoflurane and propofol on organ blood flow in a porcine model with a left ventricular assist device (LVAD). Ten healthy minipigs were divided into 2 groups (5 per group) according to the anesthetic received (sevoflurane or propofol). A Biomedicus centrifugal pump was implanted. Organ blood flow (measured using colored microspheres), markers of tissue injury, and hemodynamic parameters were assessed at baseline (pump off) and after 30 minutes of partial support. Blood flow was significantly higher in the brain (both frontal lobes), heart (both ventricles), and liver after 30 minutes in the sevoflurane group, although no significant differences were recorded for the lung, kidney, or ileum. Serum levels of alanine aminotransferase and total bilirubin were significantly higher after 30 minutes in the propofol group, although no significant differences were detected between the groups for other parameters of liver function, kidney function, or lactic acid levels. The hemodynamic parameters were similar in both groups. We demonstrated that, compared with propofol, sevoflurane increases blood flow in the brain, liver, and heart after implantation of an LVAD under conditions of partial support.

Anesthetic management of children with in situ Berlin Heart EXCOR

Modern mechanical devices can support children with severely impaired cardiac function until a donor heart is found for transplantation or native function recovers. Pediatric heart transplantation offers a good chance of survival with a high quality of life to individuals with limited life expectancy and/or severe limitation to daily activities, but many die on the transplant list or are not listed because of a shortage of donor organs. In recent cohorts, there is better outcome when ventricular assist devices (VADs) rather than extracorporeal membrane oxygenation are used as a 'bridge' to transplantation. Anesthesiologists working in centers where VADs are available may increasingly be asked to provide anesthesia to children with such devices in situ, including procedures outside the cardiac surgical operating room. The Berlin Heart EXCOR device is a VAD system with increasing popularity in pediatric practice and has system components available in sizes suitable even for neonates. Postimplantation considerations include hemodynamics, thromboembolic complications and their prevention by anticoagulation, antimicrobial therapy, and the rehabilitation and mobilization of recipients. VAD-specific emergencies must be recognized and managed appropriately by anesthesiologists looking after Berlin Heart recipients. These include malignant dysrhythmias, sudden loss of VAD output, air or clot embolism, and sudden cyanosis. Provision of anesthesia for patients with an in situ Berlin Heart requires attention to particular considerations in preoperative assessment, induction, maintenance, and postoperative care.

Assisting the failing heart

Anesthesiologists increasingly encounter patients who have a spectrum of heart failure ranging from stable chronic heart failure to acute heart failure to cardiogenic shock. Improved medical therapy has increased the survival of patients who have chronic heart failure but not of patients who have acute heart failure. New surgical techniques and mechanical devices may offer alternatives to certain patients who have refractory heart failure This article provides an overview of established and newer pharmacologic and nonpharmacologic therapies and surgical interventions to manage patients who have heart failure, including the perioperative management of heart transplantation and ventricular assist devices.

Cardiomyopathic etiology and SERCA2a reverse remodeling during mechanical support of the failing human heart

Many hearts in end-stage, chronic failure (CHF) retain the capacity to reverse abnormal expression of genes regulating myocyte calcium cycling when supported with a left ventricular assist device (LVAD). In the present study, we determined whether LVAD-induced upregulation of the gene encoding for the key calcium cycling protein sarcoplasmic endoreticular calcium adenosine triphosphatase subtype 2a (SERCA2a) is influenced by the nature of underlying disease broadly characterized as ischemic (ICM) or idiopathic dilated (DCM) cardiomyopathy. Data from Northern blot analysis of SERCA2a messenger (m)RNA within 84 heart samples (50 CHF [23 DCM and 27 ICM] and 34 CHF+LVAD [18 DCM and 16 ICM]) were used for characterizing gene expression. In addition, measurements of the force-frequency relationship (FFR), a reflection of in vivo SERCA2a function, were obtained in myocardial trabeculae isolated from 75 hearts (51 CHF [29 DCM and 22 ICM] and 24 CHF+LVAD [10 DCM and 14 ICM]). SERCA2a mRNA demonstrated upregulation after LVAD that was not influenced by ICM or DCM. However, only in DCM hearts was the proportion of trabeculae exhibiting a normal FFR increased after LVAD. Thus, although upregulated SERCA2a gene expression after LVAD support is independent of myopathic origin, normalization of myocardial FFR, an index of SERCA2a function, is not. These data provide new insight into the process of cardiac "reverse molecular remodeling," and underscore potential differences in the impact of disease processes on posttranscriptional events.

Endotoxaemia during left ventricular assist device insertion: relationship between risk factors and outcome

BACKGROUND

Endotoxaemia, caused by splanchnic ischaemia during surgery, is believed to trigger systemic inflammation and cause postoperative organ dysfunction. A relationship between the plasma concentration of endotoxin during surgery and known risk factors for postoperative morbidity and mortality (e.g. age, abnormal gastric tonometric variables) and adverse outcome after surgery has not been demonstrated.

METHODS

In a prospective study, the plasma concentration of endotoxin was measured in 12 patients undergoing implantation of a left ventricular assist device. Automated air gastric tonometry was performed in all patients. The relationship between plasma endotoxin concentration, risk factors, and postoperative outcome was explored.

RESULTS

Carbon dioxide gap increased from 0.7 (0.3) to 3.6 (1.6) kPa at the end of surgery. Endotoxin was detected in one of 12 patients at baseline and in nine of 12 patients at the end of surgery (P=0.003). A high plasma concentration of endotoxin at the end of surgery was associated with a higher carbon dioxide gap (r=0.59, P<0.05), and a higher postoperative multiple organ dysfunction score (r=0.7, P=0.01).

CONCLUSIONS

The finding of an association between high intraoperative plasma concentrations of endotoxin, abnormal gastric tonometric variables and adverse outcome supports the view that endotoxaemia is caused by gut hypoperfusion during surgery and is associated with postoperative organ dysfunction.

Anesthetic Management for Implantation of the Jarvik 2000??? Left Ventricular Assist System

The Jarvik 2000 Heart(TM) is a left ventricular assist device that produces continuous nonpulsatile axial flow by means of a single, rotating, vaned impeller. Anesthetic and perioperative considerations of the Jarvik 2000 Heart(TM) differ from those of conventional assist devices. The Jarvik 2000 is implanted within the left ventricle through a left thoracotomy, which is aided by left lung isolation. A brief period of cardiopulmonary bypass and induced ventricular fibrillation facilitate implantation. Transesophageal echocardiography is essential to assure proper intraventricular positioning of the device and aortic outflow, confirmed by observation of aortic valve opening in the presence of adequate left ventricular volume. Because continuous flow devices function best in the presence of lower systemic and pulmonary vascular resistance, milrinone was preferentially used as an inotropic drug. In the first group of 10 patients to receive the Jarvik 2000, the pump provided a cardiac output of up to 8 L/min, depending on preload, afterload, and pump speed. There were no early perioperative deaths. The average support duration was 81.2 days; the range was 13-214 days. Seven of the 10 patients survived to transplantation. Survivors underwent complete physical rehabilitation during pump support.

IMPLICATIONS

The Jarvik 2000 is a left ventricular assist device that produces continuous nonpulsatile axial flow by means of a rotating, vaned impeller. Because the anesthetic considerations differ from those of conventional left ventricular assist devices, we report the perioperative management of the first 10 patients who participated in a bridge-to-transplantation feasibility study of the Jarvik 2000.

Mechanical Support After Cardiac Surgery

Mechanical circulatory support for low cardiac output after cariac surgery was first attempted in 1962. Since then, many ventricular assist devices have been developed and employed. The following is a discussion of the history, demographics, inications, and devices used for mechanical circulatory suport in this setting. lntra-aortic balloon pulsation, pulsatile verus non-pulsatile flow, volume bypass, roller and centrifugal pumps, extracorporeal membrane oxygenation, and imlantable devices are reviewed. Early postoperative care, reovery and weaning from mechanical circulatory support, and the special issues that relate to biventricular failure and control of right-sided ventricular function, as well as anticoagulation, and sepsis are addressed.

The anesthetic considerations in patients with ventricular assist devices presenting for noncardiac surgery: a review of eight cases

IMPLICATIONS

The number of patients supported by ventricular assist devices (VADs) that present for noncardiac surgery is increasing in our institution. Our recent experience with eight such patients is reported, along with a review of the most commonly implanted VADs and the anesthetic implications and considerations for VAD-supported patients undergoing noncardiac surgery.