Percutaneous Left Ventricular Assist Devices: Clinical Uses, Future Applications, and Anesthetic Considerations

The increasing importance of percutaneous mechanical circulatory assist device therapy in heart failure management

Introduction:

Advances in medical and surgical care have made it possible for an increasing number of patients with Congenital Heart disease (CHD) to live into adulthood. Transposition of the great vessels (TGV) is the most common cyanotic congenital cardiac disease where the right ventricle serves as systemic ventricle. It is not uncommon for these patients to have systemic ventricular failure requiring transplantation.

Study Design:

Hemodynamic decompensation in these patients can be swift and difficult to manage. Increasingly percutaneous LVAD's such as the Impella (Abiomed, Mass, USA) are gaining popularity in these situations owing to their relative ease of placement, both in and outside of the operating room.

Conclusion:

In this paper we demonstrate that Impella (IMP) CP placement through the axillary artery approach shows to be suitable option for short term cardiac support and improvement of end organ perfusion in anticipation of cardiac transplantation.

[Near-infrared spectroscopy during cardiopulmonary resuscitation and mechanical circulatory support: From the operating room to the intensive care unit]

BACKGROUND

Near infrared spectroscopy (NIRS) allows continuous measurement of cerebral regional oxygen saturation (rSO2). It is a weighted saturation value derived from approximately 70-75 % venous, 20-25 % arterial and 2.5-5 % capillary blood. In contrast to pulse oximetry, NIRS is independent of pulsatile flow. Therefore, it is also applicable during extracorporeal circulation, cardiopulmonary resuscitation (CPR), and hypothermia.

OBJECTIVES

The purpose of this work is to describe the application of cerebral and somatic NIRS in cardiology and cardiac surgery patients in the operation room, during and after CPR, and during the intensive care unit stay.

MATERIALS AND METHODS

This article is based on peer-reviewed literature from PubMed.

RESULTS

Interventions based on decline of cerebral NIRS values during on-pump cardiac surgery can reduce major organ morbidity and mortality; however, the appearance of a postoperative cognitive dysfunction is scarcely influenced. Persisting of low cerebral oximetry values during resuscitation is a marker for not achieving return of spontaneous circulation under normothermia. NIRS is an additional method for monitoring that can be used during extracorporeal circulation.

CONCLUSION

NIRS is a rapidly available, user-friendly, and noninvasive method for continuous measurement of rSO2. NIRS provides additional information about tissue oxygenation especially during resuscitation and extracorporeal circulatory assist support. Recommendations concerning the use of NIRS for standard monitoring during resuscitation and mechanical circulatory support are not currently available. Further studies are required to show if use of NIRS can reduce pulse control and hands-off times during resuscitation and if use of NIRS can improve outcome after CPR and mechanical circulatory support.

The role of percutaneous left ventricular assist devices during ventricular tachycardia ablation

Ventricular tachycardia (VT) is a common but serious arrhythmia that significantly adds to the morbidity and mortality of patients with structural heart disease. Percutaneous catheter ablation has evolved to be standard therapy to prevent recurrent implantable cardioverter defibrillator shocks from VT in patients on antiarrhythmia medications. Procedural outcomes in patients with structural heart disease are often limited by haemodynamically unstable VT. Although substrate- and pace-mapping techniques have become increasingly popular for VT ablation, these approaches can often times may not address inducible clinical and non-clinical VTs. Activation and entrainment mapping can help the operator target VT exit sites in a precise fashion minimizing the amount of radiofrequency ablation needed for a successful ablation. An evolving alternative strategy that allows induction and mapping of VT in the setting of severe cardiomyopathy and haemodynamic instability is through maintaining perfusion with a percutaneous ventricular assist device (pVAD). This review will discuss these pVAD technologies, distinguish technical applications of use, highlight the published clinical experience, provide a clinical approach for support device selection, and discuss use of these technologies with current mapping and navigational systems.

Anesthetic considerations for the patient undergoing therapy for advanced heart failure

PURPOSE OF REVIEW

Advanced heart failure (AHF) affects a growing percentage of our population. The anesthesiologist must be cognizant of the perioperative considerations of patients undergoing state-of-the-art therapy for AHF. These therapies include classic and novel agents to improve systolic function, neurohormonal modulators, heart rhythm and synchronization management and mechanical support of the circulation. The perioperative considerations and recommendations may range from invasive hemodynamic monitoring, management of proper inotropic support to maintain left ventricular and right ventricular systolic function, isolation from electromagnetic interference in patients with rhythm management devices, maintenance of appropriate systemic and pulmonary vascular resistance, and surgical planning and anticoagulant management.

RECENT FINDINGS

Studies of the efficacy and hemodynamic changes of patients on inotropic therapy (milrinone, levosimendan, and istaroxime) and neuropeptide (nesiritide) therapy will be reviewed. Perioperative considerations of patients on mechanical circulatory support will be discussed. The need for implementation of temporary mechanical support for noncardiac surgery will be discussed.

SUMMARY

A working knowledge of AHF treatments and perioperative considerations is necessary for all anesthesiologists as more patients receiving therapy will be presenting for all types of surgical procedures.

[Left ventricular assist devices in cardiogenic shock]

Cardiogenic shock is the leading cause of in-hospital death for myocardial infarction. Despite therapeutic improvements, such as medical treatment with inotropes, myocardial revascularization, circulatory assistance can be an option. Intra-aortic balloon pumping is highly recommended in the presence of haemodynamic impairment. If the patient continues to deteriorate and cardiac function cannot maintain adequate circulation to prevent end-organ failure, several mechanical circulatory assist devices can be considered: extracorporeal membrane oxygenator (ECMO), Impella(®)… These devices should be used at tertiary centres either as bridge to recovery or as bridge to transplantation or as bridge to long-term left ventricle assist device.