Effects of a percutaneous mechanical circulatory support device for medically refractory right ventricular failure

Development of a Double-Lumen Cannula for a Percutaneous RVAD

The objectives were to design/fabricate a double-lumen cannula (DLC) for a percutaneous right ventricular assist device (pRVAD) and to test the feasibility/performance of this pRVAD system. A 27 Fr DLC prototype was made and tested in six adult sheep. The pRVAD DLC was inserted into the right jugular vein; advanced through the superior vena cava, the right atrium (RA), the right ventricle (RV); ending in the pulmonary artery (PA). A CentriMag pump and optional gas exchanger were connected to the DLC. Blood was withdrawn from RA, pumped through gas exchanger, and perfused PA. Maximal pumping flow was maintained for 2 hours. The pRVAD DLC was successfully deployed in all six sheep. In first three sheep, maximal average pumping flow was less than 3 L/min because the DLC was advanced too far with drainage opening against RA side wall. In last three sheep with well-positioned DLC, average maximal flow was more than 3.5 L/min. The gas exchanger provided up to 230 ml/min CO2 removal and 174 ml/min O2 transfer. Our DLC-based pRVAD system is feasible for percutaneous right heart and respiratory assistance through a single cannulation. The pRVAD DLC can be easily placed prophylactically during left ventricular assist device implantation and removed as needed without additional open chest procedures.

2015 SCAI/ACC/HFSA/STS Clinical Expert Consensus Statement on the Use of Percutaneous Mechanical Circulatory Support Devices in Cardiovascular Care (Endorsed by the American Heart Association, the Cardiological Society of India, and Sociedad Latino Americana de Cardiologia Intervencion; Affirmation of Value by the Canadian Association of Interventional Cardiology-Association Canadienne de Cardiologie d'intervention)

Although historically the intra-aortic balloon pump has been the only mechanical circulatory support device available to clinicians, a number of new devices have become commercially available and have entered clinical practice. These include axial flow pumps, such as Impella(®); left atrial to femoral artery bypass pumps, specifically the TandemHeart; and new devices for institution of extracorporeal membrane oxygenation. These devices differ significantly in their hemodynamic effects, insertion, monitoring, and clinical applicability. This document reviews the physiologic impact on the circulation of these devices and their use in specific clinical situations. These situations include patients undergoing high-risk percutaneous coronary intervention, those presenting with cardiogenic shock, and acute decompensated heart failure. Specialized uses for right-sided support and in pediatric populations are discussed and the clinical utility of mechanical circulatory support devices is reviewed, as are the American College of Cardiology/American Heart Association clinical practice guidelines.

In vitro Evaluation of a Novel Pulsatile Right Heart Assist Device - the Perkat System

Purpose

Acute right ventricular failure is a life-threatening condition with poor prognosis. It occurs as a result of right ventricular infarction, postcardiac transplantation, or postimplantation of a left ventricular assist device. Temporary mechanical right ventricular support could be a reasonable treatment option. Therefore, we developed a novel percutaneously implantable device.

Methods

The PERKAT device consists of a self-expandable chamber covered with multiple inflow valves carrying foils. A flexible outlet tube with a pigtail tip is attached to the distal end. PERKAT is designed for percutaneous implantation through the femoral vein (18 French sheath). The chamber is expanded in the inferior vena cava while the outlet tube bypasses the right heart and the pigtail tip is lying in the pulmonary trunk. An IABP balloon is inserted into the chamber and connected to an IABP console. Balloon deflation generates blood flow from the vena cava into the chamber through the foil valves. During inflation blood is pumped through the tube into the pulmonary arteries.

Results

In vitro experiments were performed using 30 mL and 40 mL IABP balloons. IABP inflation/deflation times were set to 80, 90, 100, and 110 per min with an afterload of 22 mmHg and 44 mmHg. PERKAT generated flow rates between 1.6 to 3.1 l/min, depending on balloon size, pump cycle, and afterload.

Conclusions

The novel percutaneously implantable right ventricular assist device offers emergency support of up to 3 l/min. Based on the successful in vitro evaluation, we recommend the system as a promising approach for treatment of patients in need of RV support.

Temporary mechanical circulatory support: a review of the options, indications, and outcomes

Cardiogenic shock remains a challenging disease entity and is associated with significant morbidity and mortality. Temporary mechanical circulatory support (MCS) can be implemented in an acute setting to stabilize acutely ill patients with cardiomyopathy in a variety of clinical situations. Currently, several options exist for temporary MCS. We review the indications, contraindications, clinical applications, and evidences for a variety of temporary circulatory support options, including the intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), CentriMag blood pump, and percutaneous ventricular assist devices (pVADs), specifically the TandemHeart and Impella.

The challenges in the management of right ventricular infarction

In recent years, right ventricular (RV) infarction seems to be underdiagnosed in most cases of acute myocardial ischaemia despite its frequent association with inferior-wall and, occasionally, anterior-wall myocardial infarction (MI). However, its initial management is drastically different from that of left ventricular MI, and studies have indicated that RV infarction remains associated with significant morbidity and mortality, even in the mechanical reperfusion era. The pathophysiology of RV infarction involves the interaction between the right and left ventricle (LV), and the mechanism has been clarified with the advent of diagnostic non-invasive modalities, such as echocardiography and cardiac magnetic resonance. In recent years, considerable progress has been made in the treatment of RV infarction; early revascularization remains the cornerstone of the management, and fluid resuscitation, with appropriate target selection, is necessary to maintain appropriate preload. Early recognition in intensive care with clear understanding of the pathophysiology is essential to improve its prognosis. In terms of management, the support strategy for RV dysfunction is different from that for LV dysfunction since the former may often be temporary. Along with early reperfusion, maintenance of an adequate heart rate and atrioventricular synchrony are essential to sustain a sufficient cardiac output in patients with RV infarction. In refractory cases, more intensive mechanical support is required, and new therapeutic options, such as Tandem-Heart or percutaneous cardiopulmonary support systems, are being developed.

Percutaneous mechanical assist for severe cardiogenic shock due to acute right ventricular failure

Acute right ventricular failure can lead to severe cardiogenic shock and death. Recovery may be achieved with early supportive measures. In many patients, intravenous fluid and inotropic resuscitation is inadequate to improve cardiac output. In these cases, percutaneous mechanical assist may provide a non-surgical bridge to recovery. Herein, we describe a case series of patients with severe, refractory cardiogenic shock due to acute right ventricular failure who received a continuous flow percutaneous ventricular device primarily utilizing the right internal jugular vein for out flow cannula placement.

Short-term mechanical circulatory support for recovery from acute right ventricular failure: clinical outcomes

BACKGROUND

Acute right ventricular failure (ARVF) refractory to optimal medical management may require rescue therapy with mechanical circulatory support (MCS). The RV exhibits a greater capacity for rapid recovery than the left ventricle, making devices designed specifically for temporary RV MCS attractive. We report our experience with the Impella Right Direct (RD) and Right Peripheral (RP) temporary ventricular assist devices (Abiomed, Danvers, MA) in patients with ARVF.

METHODS

We conducted a retrospective cohort study examining the clinical outcomes of consecutive patients supported with the Impella RD or RP at 2 institutions during a 6-year period.

RESULTS

During the study period, 18 patients (67% men; mean age 57 ± 10 years) received MCS, 15 with the Impella RD and 3 with the Impella RP. Before RV MCS, all patients required intravenous inotropes, 7 (39%) required inhaled nitric oxide, 7 (39%) required intra-aortic balloon counterpulsation, and 2 (11%) had experienced a cardiac arrest. Device implantation resulted in an improvement in cardiac index (2.1 ± 0.1 liters/min/m(2) pre-implant vs 2.6 ± 0.2 liters/min/m(2) post-implant, p = 0.04) and reduced central venous pressure (22 ± 5 vs 15 ± 4 mm Hg, p < 0.01). Fourteen (78%) patients recovered sufficient RV function to facilitate device explanation after 7 days (range, 2-19 days) of support, and 4 (22%) patients died on support after 6 days (range 1-11 days). Survival to 30 days was 72% and to 1 year was 50%. At 1-year follow-up, the mean New York Heart Association functional classification was 1.3 ± 0.5, and only 1 patient demonstrated severe RV dysfunction on echocardiography.

CONCLUSIONS

Most patients with ARVF rapidly recover sufficient RV function to facilitate device explantation, highlighting an expanding role for minimally invasive temporary RV assist devices optimized for the treatment of recoverable ARVF.

Can the temporary use of right ventricular assist devices bridge patients with acute right ventricular failure after cardiac surgery to recovery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: Can the temporary use of right ventricular assist devices (RVADs) bridge patients to recovery who suffer acute right ventricular failure after cardiac surgery? More than 183 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Indications for surgical intervention included coronary artery bypass surgery, valve replacement, post-heart transplant and left ventricular assist device insertion. Significant reductions in central venous pressure (P = 0.005) and mean pulmonary artery pressures (P < 0.01) were reported during and after RVAD support. Furthermore, increases in right ventricular cardiac output (P < 0.05), right ventricular ejection fraction (P < 0.05), right ventricular stroke work (P < 0.05) and pulmonary artery oxygen saturations (P < 0.05) were also seen. Assessment by one study showed that on Day 7 after RVAD removal, the right ventricular ejection fraction had increased by up to 40%. Dynamic echocardiography studies performed before, during and after RVAD placement demonstrated that after RVAD implantation, right ventricular end-diastolic dimensions (P < 0.05) and right atrial dimensions decreased (P < 0.05) and right ventricular ejection fraction (P < 0.05) increased. Although several studies successfully weaned patients from an RVAD, there were several complications, including bleeding requiring surgical intervention. However, this may be reduced by using percutaneous implantation (bleeding incidence: 4 of 9 patients) rather than by a surgically implanted RVAD (bleeding incidence: 5 of 5 patients). However, mortality is higher in percutaneous RVAD patients rather than in surgical RVAD (80-44%) patients. Causes of death cited for patients on an RVAD included multiorgan failure, sepsis, thromboembolic events, reoccurring right heart failure and failure to wean due to persistent right ventricular failure. We conclude that RVADs have been successfully used to bridge patients to recovery after cardiac surgery; however, RVADs carry numerous risks and a high mortality rate.

Defining the role for percutaneous mechanical circulatory support devices for medically refractory heart failure

Despite significant advances in the management of heart failure, short-term mortality due to advanced heart failure and cardiogenic shock remains high. Developed over the past few decades, percutaneous circulatory support devices offer a rapid and effective approach to slow the downward spiral of hemodynamic instability in patients presenting with decompensated heart failure until a more definitive strategy is pursued or patients recover. This review will discuss the goals of percutaneous circulatory support, the types of devices currently available, and the most recent clinical datasets examining the utility of these devices.

Percutaneous Circulatory Assist Devices for Right Ventricular Failure

Heart failure is a major cause of global morbidity and mortality affecting nearly 24 million individuals worldwide. Although the importance of right ventricular (RV) function has become more apparent over the past few decades, few therapies specifically target RV failure. Over the past 3 decades, significant advances in percutaneously delivered circulatory support devices has led to the recent development of devices specifically designed for RV failure. In this review, RV pathophysiology, device options, and clinical data exploring the utility of percutaneous RV support devices are discussed.

Future Directions for Percutaneous Mechanical Circulatory Support Devices

Outcomes of patients in cardiogenic shock remain high, but the development of novel percutaneous mechanical circulatory support devices offers additional therapeutic options. Hand in hand with innovations in device technology, however, must also come development of integrated circulatory support networks focusing on rapid assessment of patients, multidisciplinary discussion, and timely therapeutic intervention. This article summarizes some of the recent developments in device technology; potential procedures for patient risk stratification, device selection, and response to therapy; management of vascular access to reduce insertion point complications; and some of the expanding potential roles of percutaneous mechanical circulatory support devices.

Preoperative Evaluation and Perioperative Management of Right Ventricular Failure After Left Ventricular Assist Device Implantation

Right ventricular (RV) failure continues to be a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. Preoperative evaluation of RV function with a variety of clinical, laboratory, echocardiographic, and hemodynamic variables is essential to ensure appropriate patient selection for LVAD therapy but remains imperfect. Therefore, clinicians involved in the care of these patients need to be prepared to manage RV failure after LVAD placement. Perioperative management of RV failure after LVAD implantation requires minimization of intraoperative RV ischemia, maintenance of appropriate filling pressure, supportive therapy with pulmonary vasodilators and inotropes, and surgical interventions such as RV assist devices in select cases. This article reviews the incidence of RV failure with LVAD implantation, preoperative predictors of RV failure, and perioperative management strategies.

Heart rescue: the role of mechanical circulatory support in the management of severe refractory cardiogenic shock

PURPOSE OF REVIEW

Cardiogenic shock is present in 3.5% of patients presenting with acute decompensated heart failure. Despite advances in therapy, mortality remains high, approaching 70% in some settings. Recent management strategies have incorporated the use of mechanical circulatory support (MCS), which has been associated with better survival in nonrandomized trials. MCS is increasingly used in the acute setting and has become an important treatment modality for cardiogenic shock.

RECENT FINDINGS

Small studies have demonstrated improved survival when MCS is instituted early in the management of cardiogenic shock. Numerous case reports support the benefit of MCS for various causes of cardiogenic shock, including acute myocardial infarction, cardiac allograft rejection, myocarditis and refractory arrhythmias.

SUMMARY

This article will review novel strategies in the management of cardiogenic shock including percutaneous MCS (intra-aortic balloon pump, Impella, TandemHeart, venoarterial extracorporeal membrane oxygenation) and surgically implanted devices (CentriMag) that are used for short-term management. We will review the mechanisms involved in cardiogenic shock and discuss management and device selection strategies.