Ventricular Assist Device in Patients With Prosthetic Heart Valves

Survival following a concomitant aortic valve procedure during left ventricular assist device surgery: an ISHLT Mechanically Assisted Circulatory Support (IMACS) Registry analysis

Aims

The aim of this study was to compare early‐ and late‐term survival and causes of death between patients with and without a concomitant aortic valve (AoV) procedure during continuous‐flow left ventricular assist device (LVAD) surgery.

Methods and results

All adult primary continuous‐flow LVAD patients on the International Society of Heart and Lung Transplantation (ISHLT) Mechanically Assisted Circulatory Support (IMACS) Registry (n = 15 267) were included in this analysis and stratified into patients submitted to a concomitant AoV procedure (AoV replacement or AoV repair) and patients without an AoV procedure. The primary outcome was early (≤90 days) survival post‐LVAD surgery. Secondary outcomes were late survival (survival during the entire follow‐up period) and conditional survival (in patients who survived the first 90 days post‐LVAD surgery), and determinants. Patients who underwent concomitant AoV replacement (n = 457) had significantly reduced late survival compared with patients with AoV repair (n = 328) or without an AoV procedure (n = 14 482) (56% vs. 61% and 62%, respectively; P = 0.001). After adjustment for other significant predictors, concomitant AoV replacement remained an independent predictor for early [hazard ratio (HR) 1.226, 95% confidence interval (CI) 1.037–1.449] and late (HR 1.477, 95% CI 1.154–1.890) mortality. However, patients undergoing AoV replacement or repair, in whom the presence of moderate‐to‐severe AoV regurgitation was diagnosed prior to LVAD implantation, had survival similar to patients not undergoing AoV interventions.

Conclusions

Concomitant AoV surgery in patients undergoing LVAD implantation is an independent predictor of mortality. Additional research is needed to determine the best AoV surgical strategy at the time of LVAD surgery.

Guidelines for the Use of Transesophageal Echocardiography to Assist with Surgical Decision-Making in the Operating Room: A Surgery-Based Approach: From the American Society of Echocardiography in Collaboration with the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons

Intraoperative transesophageal echocardiography is a standard diagnostic and monitoring tool employed in the management of patients undergoing an entire spectrum of cardiac surgical procedures, ranging from "routine" surgical coronary revascularization to complex valve repair, combined procedures, and organ transplantation. Utilizing a protocol as a starting point for imaging in all procedures and all patients enables standardization of image acquisition, reduction in variability in quality of imaging and reporting, and ultimately better patient care. Clear communication of the echocardiographic findings to the surgical team, as well as understanding the impact of new findings on the surgical plan, are paramount. Equally important is the need for complete understanding of the technical steps of the surgical procedures being performed and the complications that may occur, in order to direct the postprocedure evaluation toward aspects directly related to the surgical procedure and to provide pertinent echocardiographic information. The rationale for this document is to outline a systematic approach describing how to apply the existing guidelines to questions on cardiac structure and function specific to the intraoperative environment in open, minimally invasive, or hybrid cardiac surgery procedures.

A case series of patients with left ventricular assist devices and concomitant mechanical heart valves

Mechanical heart valves left in situ at the time of left ventricular assist device (LVAD) implantation are thought to potentially increase the risk of thromboembolism. Recommendations exist to replace dysfunctional mechanical mitral valves and any mechanical aortic valves at the time of LVAD implantation. Due to potential increases in cardiopulmonary bypass time and associated comorbidities with valve replacement, leaving a functional mechanical valve in place at LVAD implantation has been suggested to be a safe option. We retrospectively reviewed all patients with prior mechanical mitral or aortic valves undergoing LVAD implantation at our center between 2012 and 2017. Echocardiograms were read by a single cardiologist to assess for mechanical valve dysfunction. We identified 15 patients. Five patients had major bleeding requiring transfusion. On follow-up, 2 patients had hemorrhagic stroke and 2 had transient ischemic attach/ischemic stroke. In addition, 2 patients had LVAD thrombosis and 2 patients had LVAD driveline malfunction. Mild mechanical valve regurgitation was identified on follow-up echocardiograms of 2 patients. Rate of complications in patients with mechanical valves undergoing LVAD implantation was comparable to that reported for the general LVAD population. Leaving a functional mechanical valve in place at the time of LVAD implantation could be a reasonable alternative to valve replacement. More data are required to further guide patient care in these individuals.

Continuous-flow left ventricular assist device implantation in patients with preexisting mechanical mitral valves: a systematic review

Introduction: A preexisting mechanical mitral valve (MMV) is thought to be a thrombogenic risk factor after continuous-flow left ventricular assist device (CF-LVAD) implantation. We sought to evaluate the management and outcomes of preexisting MMVs in patients following CF-LVAD implantation.Areas covered: An electronic search was performed to identify the presence of an MMV at the time of CF-LVAD implantation. Of the 1,168 studies identified, only five studies consisting of seven CF-LVAD patients met the inclusion criteria. Patient-level data were extracted and analyzed.Expert opinion: The median patient age was 54 (IQR: 42-61) years and 71.4% (5/7) were male. Non-ischemic cardiomyopathy was the predominant etiology (83.3%, 5/6) of heart failure, and bridge-to-transplant the predominant indication (85.7%, 6/7) for CF-LVAD. Aortic valve prosthesis was present in 42.9% (3/7) of patients. Median time from MMV to CF-LVAD placement was 6.0 years (IQR: 1.3-15.0). The median lower limit of the INR range was 2.8 (IQR: 2.1-3.0) and upper limit of the INR range was 3.5 (IQR: 3.1-3.5). During a median follow-up time of 120 (IQR: 70-201) days, there were no major GI bleeds or clinically significant thromboembolic complications. With adequate anticoagulation, preexisting MMVs in CF-LVAD patients did not result in clinically significant thromboembolic events.

Left Ventricular Assist Device: What the Internist Needs to Know. A Review of the Literature

Left ventricular assist devices (LVADs) have revolutionized therapy for patients with Stage D heart failure (HF) with reduced systolic function providing not only improved survival benefits but also meaningful changes in quality of life and functional capacity. With technological advances and improved durability of devices, length of survival has significantly improved. With continued organ donor shortage, LVADs are frequently serving as a substitute for cardiac transplant as destination therapy, particularly among the elderly. Internists not only face the important challenge of identifying the patients in need referral for these advanced therapies, they are also faced with the challenges of taking care of these patients. This review will help the internists to better understand the present status, indications and advances in LVADs and also understand the complications and adverse effects associated with these devices.

Minimally-invasive LVAD Implantation: State of the Art

Nowadays, the worldwide number of left ventricular assist devices (LVADs) being implanted per year is higher than the number of cardiac transplantations. The rapid developments in the field of mechanical support are characterized by continuous miniaturization and enhanced performance of the pumps, providing increased device durability and a prolonged survival of the patients. The miniaturization process enabled minimally-invasive implantation methods, which are associated with generally benefitting the overall outcome of patients. Therefore, these new implantation strategies are considered the novel state of the art in LVAD surgery.

In this paper we provide a comprehensive review on the existing literature on minimally-invasive techniques with an emphasis on the different implantation approaches and their individual surgical challenges.

Mitral valve and short-term ventricular assist devices; potential mechanical complications

Mechanical complications of ventricular assist devices (VADs) are rare but serious. The authors describe two cases of different mechanical complications of VADs that can affect the mitral valve. Attention should be paid to the position of the inflow/outflow cannula after off-loading of the ventricle, especially in acute heart failure and normal atrial dimensions. Complete off-loading of the left ventricle in the presence of a bioprosthetic mitral valve might cause fusion of the valve leaflets leading to mitral stenosis, which will call for another intervention.

Long-term left ventricular support in patients with a mechanical aortic valve

OBJECTIVES

The presence of a mechanical prosthesis has been regarded as an increased risk of thromboembolic complications and as a relative contraindication for a left ventricular assist device (LVAD). Five patients in our center had a mechanical aortic valve at the time of device implantation and were studied regarding thromboembolic complications.

DESIGN

Five patients operated upon with an LVAD (1 HeartMate I™, 4 HeartMate II™) between 2002 and 2011 had a mechanical aortic valve at the time of implantation. The first patient had a patch closure of the aortic valve. In four patients, the prosthesis was left in place. Anticoagulants included aspirin, warfarin, and clopidogrel.

RESULTS

The average and accumulated treatment times were 150 and 752 days, respectively. Three of the five patients showed early signs of valve thrombosis on echo with concomitant valve dysfunction. Four patients were transplanted without thromboembolic events during pump treatment. One patient died from a hemorrhagic stroke after 90 days on the LVAD.

CONCLUSIONS

The strategy of leaving a mechanical heart valve in place at the time of LVAD implantation in five patients led to valvular thrombosis in three but did not provoke embolic events. It increased the complexity of postoperative anticoagulation.

Patient selection for ventricular assist devices: a moving target

The number of patients with advanced heart failure that has become unresponsive to conventional medical therapy is increasing rapidly. One of the most promising new alternatives to heart transplantation is use of ventricular assist devices (VADs). To date, there are no guidelines for appropriate selection for use of these devices that are approved by national societies in the field. This review addresses all of the general criteria for clinicians to keep in mind regarding when to refer a patient for evaluation and the specific issues addressed in patient selection. The field of mechanical circulatory support has advanced significantly over the past 10 years, resulting in rapid expansion of patients with advanced heart failure who can benefit from implantable devices. With progress of technology, limitations associated with age, body size, and comorbidities gradually become less prohibitive. The continuing simplification of design along with continued reduction in size of the devices, plus eventual elimination of the external drive line will make the use of VADs a superior option to heart transplant and even to medical management in many patients. We anticipate that the patient selection process outlined in the present review will continue to shift toward less advanced cases of heart failure.

Impact of a unique international conference on pediatric mechanical circulatory support and pediatric cardiopulmonary perfusion research

There is no question that the International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion is a unique event that has had a significant impact on the treatment of neonatal, infantile, and pediatric cardiopulmonary patients around the globe since 2005. This annual event will continue as long as there is a need to fill the gap for underserved patient population. It will also continue to recognize promising young investigators based on their full manuscripts for young investigator awards.

Two axial-flow Synergy Micro-Pumps as a biventricular assist device in an ovine animal model

OBJECTIVE

This study investigated the use of 2 Synergy Micro-Pumps for full biventricular assist device (BiVAD) support. We examined right-sided and left-sided hemodynamic parameters over a range of right-sided and left-sided pump speeds in an acute, fibrillating, non-beating-heart model in sheep.

METHODS

Five juvenile sheep (43 ± 2 kg) were implanted with two Synergy Micro-Pumps (CircuLite Inc, Saddle Brook, NJ), 1 in the right (RV) and 1 in the left ventricle (LV), through a median sternotomy. The RVAD outflow graft was anastomosed end-to-side to the pulmonary artery and the LVAD outflow to the ascending aorta. After surgical implantation of both pumps, ventricular fibrillation was induced and hemodynamic parameters were measured at 9 different levels of RVAD pump speed (from 20,000 to 28,000 rpm at 1,000-rpm increments), while the speed of the LVAD was set constant at 24,000, then at 26,000, and finally, at 28,000 rpm.

RESULTS

At a fixed LVAD speed, RVAD and LVAD flow both increased identically as RVAD speed was increased. This was due to redistribution of blood volumes that resulted in resetting of pressure gradients across each pump and each vascular bed in a manner dictated by the pump pressure-flow characteristics. Results were similar with LVAD set at 24,000, 26,000, or 28,000 rpm. At the highest LVAD and RVAD speeds, flow averaged 3.1 ± 0.7 liters/min, and pressures in the right atrium, pulmonary artery, left atrium, and aorta averaged 2.2 ± 3.7, 24.4 ± 6.5, 22.4 ± 5.5, and 56.6 ± 8.5 mm Hg, respectively.

CONCLUSION

BiVAD support with the 2 Synergy Micro-Pumps is feasible and able to provide full hemodynamic support in sheep. This approach holds promise for providing biventricular partial support in humans and, in particular, for full support in small adults and children.

Technique for chest compressions in adult CPR

Chest compressions have saved the lives of countless patients in cardiac arrest as they generate a small but critical amount of blood flow to the heart and brain. This is achieved by direct cardiac massage as well as a thoracic pump mechanism. In order to optimize blood flow excellent chest compression technique is critical. Thus, the quality of the delivered chest compressions is a pivotal determinant of successful resuscitation. If a patient is found unresponsive without a definite pulse or normal breathing then the responder should assume that this patient is in cardiac arrest, activate the emergency response system and immediately start chest compressions. Contra-indications to starting chest compressions include a valid Do Not Attempt Resuscitation Order. Optimal technique for adult chest compressions includes positioning the patient supine, and pushing hard and fast over the center of the chest with the outstretched arms perpendicular to the patient's chest. The rate should be at least 100 compressions per minute and any interruptions should be minimized to achieve a minimum of 60 actually delivered compressions per minute. Aggressive rotation of compressors prevents decline of chest compression quality due to fatigue. Chest compressions are terminated following return of spontaneous circulation. Unconscious patients with normal breathing are placed in the recovery position. If there is no return of spontaneous circulation, then the decision to terminate chest compressions is based on the clinical judgment that the patient's cardiac arrest is unresponsive to treatment. Finally, it is important that family and patients' loved ones who witness chest compressions be treated with consideration and sensitivity.

Artificial organs 2010: a year in review

In this Editor's Review, articles published in 2010 are organized by category and briefly summarized. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, and the International Society for Rotary Blood Pumps, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level."Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide such meaningful suggestions to the author's work whether eventually accepted or rejected and especially to those whose native tongue is not English. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, Wiley-Blackwell, for their expert attention and support in the production and marketing of Artificial Organs. In this Editor's Review, that historically has been widely received by our readership, we aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. We look forward to recording further advances in the coming years.