Advances In Mechanical Circulatory Support Research Articles

The dawn of the ISHLT Mechanical Assisted Circulatory Support (IMACS) Registry: Fulfilling our mission

The promulgation of our revised mission statement in 2007 reflected the pivotal position of mechanical circulatory support (MCS) on the platform of therapeutic strategies for advanced heart and lung failure. In the realm of transplantation, the International Society for Heart and Lung Transplantation (ISHLT) Heart and Lung Transplant Registries are precious assets for our Society, as evidenced by the numerous scientific publications based on registry data. The world of MCS is rapidly evolving, with a panoply of devices populating the MCS landscape. Through our focused interest in therapeutic strategies for the treatment of advanced heart and lung failure, ISHLT is the natural home for scientific advances in MCS. The original ISHLT MCS Registry was conceived in 2000 as an effort led by Robert Kormos (ISHLT President, 1999–2000), with an initial tenure of 4 years. With the rapid evolution of MCS therapy in the United States, the National Heart, Lung, and Blood Institute (NHLBI) subsequently requested proposals to develop, manage, and guide scientific investigations from a registry dedicated to durable MCS devices. The contract was awarded to a group of investigators deeply embedded in the ISHLT, resulting in the genesis of Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). INTERMACS initiated data collection in 2006; with the rapid expansion of continuous-flow technology, the database now contains more than 4,000 device implants. With the ISHLT commitment to foster an environment of scientific exchange about MCS therapy, a portal into critical developments in the field is facilitated by the Society’s natural nexus of advanced heart failure medical science and

Ventricular Assist Devices

Patients with advanced heart failure have limited treatment options despite advances in medical management. Ventricular assist devices represent a surgical option that offers improved end-organ function, survival, and quality of life. Postoperative nursing management involves the most complicated aspects of care following cardiac surgery as well as issues unique to advanced heart failure and mechanical circulatory support. Despite growing numbers of ventricular assist device implants, literature about the challenging care of patients following ventricular assist device implantation is limited. This article focuses on the physiological basis for postoperative nursing management strategies and the most important complications of which critical care nurses need to be aware.

Ventricular Assist Devices

Patients with advanced heart failure have limited treatment options despite advances in medical management. Ventricular assist devices represent a surgical option that offers improved end-organ function, survival, and quality of life. Postoperative nursing management involves the most complicated aspects of care following cardiac surgery as well as issues unique to advanced heart failure and mechanical circulatory support. Despite growing numbers of ventricular assist device implants, literature about the challenging care of patients following ventricular assist device implantation is limited. This article focuses on the physiological basis for postoperative nursing management strategies and the most important complications of which critical care nurses need to be aware.

Mechanical assistance of the circulation during cardiogenic shock

Cardiogenic shock still has a grave prognosis. We present the recent advances in mechanical circulatory support (MCS) for the treatment of refractory cardiogenic shock. The contraindications for short-term MCS in rapid-onset cardiogenic shock are becoming fewer and the threshold for its application has been progressively lowered. Short-term MCS is increasingly used in refractory cardiac arrest and will be probably integrated as the last means in the advanced cardiopulmonary resuscitation algorithm (provided there is experienced team and technical support). Improved device technology has contributed to improved results of long-term MCS. Emergent application of long-term MCS in patients with critical cardiogenic shock after a long history of progressively deteriorating end-stage chronic heart failure should be interpreted as delayed application associated with increased mortality. Although MCS can be life saving in cardiogenic shock, the results are still suboptimal. Mortality is associated with the critical presupport state and the adverse events during MCS. Early initiation of support that meets the patient's requirements, potent support in the early phase, adverse event prevention, global combined management (surgical, interventional, medical), balanced support duration, bridging to further therapeutic modalities including heart transplantation or longer-term support, and advanced technology could offer improved results.

Advances in mechanical circulatory support: Year in review

Mechanical circulatory support (MCS) in cardiac surgery is approaching its 50th anniversary. In the early 1960s, DeBakey developed the first ventricular assist device (VAD) and, in 1966, reported its first successful use for bridge to recovery in post-cardiotomy syndrome in a 37-year-old woman. VAD utilization is among the most effective options for treatment of acute or chronic end-stage heart failure. In Europe, more MCS systems are implanted than hearts transplanted, and in the near future this will also be the case in North America. However, despite enormous progress in the field in the past 50 years, there remain many obstacles yet to be overcome. Continuous-flow pumps, introduced in the past 12 years, represent a major advance, as the associated complication rate is significantly lower than with earlier pulsatile systems. The key developments of the year 2010 are the increased numbers of studies showing the low complication rate and excellent durability of continuous-flow pumps, developments resulting from technology related to mechanical bearings and magnetic or hydrodynamic levitation. Both the improved durability and low complication rate profile have now allowed a shift from “saving the life” of patients with severe cardiogenic shock and NYHA Class IV status to “improving the quality of life” of patients with NYHA Class III or IV. Another key advancement is the smaller pump size, which enables simplified surgical implantation through sternotomy or left thoracotomy and, in some cases, without cardiopulmonary bypass. This results in a lower risk of peri-operative complications and thus allows utilization of such therapy in older or sicker patients, which was not possible with earlier types of devices. Because in some selected groups of patients with MCS the morbidity and mortality rates are approaching those of the patients who receive the “gold standard” of care—heart

The Registry of the International Society for Heart and Lung Transplantation: Twenty-seventh official adult heart transplant report—2010

The Registry of the International Society for Heart and Lung Transplantation: Twenty-seventh official adult heart transplant report—2010

Sex Matters, But to What Clinical Avail?

Despite substantial advances in mechanical circulatory support, cardiac transplantation remains the “gold standard” treatment option for eligible patients with American Heart Association/American College of Cardiology class D end-stage heart failure. Transplant survival rates have progressively improved at all time points, with 55% of recipients now surviving 10 years after transplantation, despite an increase in donor and recipient age and comorbidity and greater recipient urgency. Survival has improved with every 5- to 10-year era, but most of the mortality aversion is in the first 6 to 12 months.1,2 Article see p 401 In this issue of Circulation: Heart Failure , Weiss and colleagues3 from The Johns Hopkins University, evaluated United Network for Organ Sharing data on all first US adult heart transplantations from 1998 to 2007 (n=18,240). The authors show that female recipients had marginally ( P =0.06) worse 5-year survival than male recipients (absolute increase risk of 3.6%; 11% higher risk-adjusted mortality). However, the overall better survival in male recipients was present only in male recipients of a male donor; by using multivariable Cox modeling, they found that male recipients of a female donor (FD/MR) were 15% more likely to die than male recipients of a male donor (MD/MR). Moreover, after the addition of propensity adjustment for the likelihood of receiving a same-sex donor, the FD/MR group was 20% more likely to die than those male recipients who received a same-sex donor. The survivals of donor/recipient sex-matched female (FD/FR) and male (MD/MR) recipients were statistically indistinguishable after multivariable adjustment (with and without propensity adjustment), but when considered together, donor-recipient sex mismatches (FD/MR and MD/FR) were 14% ( P <0.001) more likely to have died at 5 years than the sex-matched group (MD/MR and FD/FR). However, among female recipients alone, the multivariable propensity-adjusted analysis revealed no increase in the risk of …

Successive Circulatory Support Stages: A Triple Bridge to Recovery from Fulminant Myocarditis

Fulminant myocarditis with rapid onset of symptoms and hemodynamic compromise is a rare indication for mechanical support. Because of the potentially reversible nature of this illness, advanced mechanical circulatory support is warranted to achieve recovery or as a bridge to transplantation. Circulatory device options currently available allow for a phased implementation of support modalities in a manner that reduces costs and patient risk. We present a patient with fulminant myocarditis where extracorporeal membrane oxygenation (ECMO) support escalated to short-term Levitronix CentriMag (Levitronix, Waltham, MA) biventricular assist devices (BiVADs). These in turn were exchanged, without major surgery, to long-term paracorporeal VADs (Thoratec, Pleasanton, CA). After rehabilitation and nearly total recovery, the patient was weaned from mechanical circulatory support after 104 cumulative days.

Advances in mechanical circulatory support

Mechanical circulatory support is expanding the treatment of advanced heart failure. The number of heart transplantations performed worldwide remains fairly static, and medical therapy alone for end stage heart failure continues to have dismal results. This article presents the authors' opinion as to the current status, challenges, and future course of the field of mechanical circulatory support. There is significant disparity between perceived and actuarial survival of a patient with the diagnosis of advanced heart failure. The traditional indications for mechanical circulatory support are becoming less relevant as the application of the therapy broadens. More devices with improved durability are becoming available, and patient selection, management, and outcomes continue to improve. Long-term myocardial recovery is possible in a population of patients with heart failure through the use of mechanical circulatory support combined with evolving pharmacologic therapy, gene therapy, and other forms of tissue regeneration (stem cells, cellular matrix). Mechanical circulatory support holds great promise in the treatment of advanced heart failure. It is critical to change the perception of both the clinician and the patient toward the prognosis of end stage heart failure. The prospect of achieving long-term myocardial recovery using mechanical support as a platform for other strategies is exciting and requires intensive future investigation.

Out‐of‐Center Extracorporeal Membrane Oxygenation for Adult Cardiogenic Shock Patients

Patients with cardiogenic shock refractory to conventional management require advanced mechanical circulatory support such as extracorporeal membrane oxygenation (ECMO). In hospitals lacking ECMO facilities, interhospital transportation is necessary for further patient management. Thirty-one adult cardiac patients, who were transported to our hospital by our ECMO transport team between January 1998 and July 2004, were enrolled in this study. The median transportation distance was 200 km (range: 3-300 km). During transportation, the ECMO circuit per se and the patients did not have complications. Of the 31 patients, 20 (64.2%) were weaned off ECMO or bridged to ventricular assist devices and 10 patients (32.1%) survived to discharge. Delayed transfer (>2 days) and high organ dysfunction score were associated with poor outcomes. The survival rate was similar to that of our in-hospital group (survival rate: 32.8%, n = 64). In conclusion, adult cardiogenic shock patients requiring interhospital ECMO transport had a reasonable chance of survival.

Strategies for Temporary Mechanical Support: Contemporary Experience with Pulsatile and Non-pulsatile Support Systems

Despite advances in mechanical circulatory support, cardiogenic shock continues to have a high mortality. We reviewed our experience with pulsatile versus non-pulsatile temporary mechanical support at our institution to determine optimal strategy for survival. From January 2001 to December 2003, mechanical support for cardiogenic shock was instituted in 38 patients. Non-pulsatile devices (NP group) were used in 22 patients and pulsatile devices (P group) in 16 patients. Indications for the NP group were post-cardiotomy shock (PCS) in 17, myocardial infarction in 2, and isolated post-cardiotomy right ventricular failure in 3 patients. In the P group, 9 had the device placed for PCS, 3 for viral myocarditis, 1 after myocardial infarction, and 3 for right ventricular (RV) failure. Overall, bleeding, limb ischemia, and multi-system organ failure were higher in NP group with 5 weaned and 3 surviving to discharge (14%). In the P group, survivors included 7 weaned and 3 transplanted patients (63%). With the exception of isolated RV failure, we obtained a dismal survival result with ECMO/centrifugal circuits for treatment of cardiogenic shock. For refractory pump failure, improved survival was achieved by using intermediate-term pulsatile devices with early transition to a chronic device and/or heart transplantation.

SHOULD ECMO BE ABANDONED FOR TREATMENT OF CARDIO-GENIC SHOCK IN ADULTS?

Purpose: Despite advances in mechanical circulatory support, cardio-genic shock continues to have a high mortality. We reviewed our recent experience with pulsatile vs non-pulsatile temporary mechanical support. Method: From January 2001-December 2003, mechanical support for cardiogenic shock was instituted in 38 patients (mean age 52±12 years). Indications for mechanical support, complications, and overall survival were examined. Results: Centrifugal pump or ECMO were used in 22 patients (non-pulsatile- NP group). Abiomed was used in 13 and Thoratec in 3 patients (pulsatile- P group). Indications in the NP group were post-cardiotomy shock (PCS) in 1 7, myocardial infarction (MI) in 2, and post-cardiotomy right ventricular (RV) failure in 3. In the P group, 9 had the device placed for PCS, 3 for myocarditis, 1 after MI, and 3 for RV failure after LVAD. Overall, bleeding, limb ischemia, and multi-system organ failure (MSOF) were higher in NP group. In the NP group, 5 patients were weaned from the device and only 3 survived to discharge (14%). These survivors had NP support for isolated RV failure. In the P group, survivors to hospital discharge included 7 weaned and 3 transplanted patients (63'). Cause of death were arrhythmia in 1 after weaning, severe preoperative brain injury in 2, and MSOF in 1 patients. Conclusion: ECMO/centrifugal support has dismal results in the treatment of cardiogenic shock and its use should be discouraged. Survival may improve with pulsatile mechanical support. For refractory heart failure, chronic VAD or transplantation remains the only solution for survival.

Invited commentary

Fortunately, postcardiotomy mechanical support is required in only 0.5% to 1.0% of cardiac operations. Extracorporeal membrane oxygenation is very versatile, providing both cardiac and pulmonary support, is portable, easy to run, and inexpensive. Vascular access can be obtained through the peripheral circulation. However, a tremendous amount of resources will be utilized to support patients who die 75% of the time. How can information provided in this and other recently published series be used to optimally manage patients? Although peripheral access is often convenient, it is associated with a very high rate of vascular complications of the lower extremity. We have utilized a distal limb perfusion catheter in the superficial femoral artery, while Doll has recommended anastamosing a 6-mm hemashield graft to the common femoral artery. Central aortic cannulation avoids peripheral vascular injuries; however, it often requires the sternum to remain open and can be associated with bleeding from around the cannulas. Attention to detail at this step of the operation will reduce bleeding and many of the complications listed in Table 4. Intraaortic balloon pump counterpulsation should be used in all patients on ECMO support and is associated with an improvement in survival in this series, as well as in our experience. The exact mechanism for this benefit is not known. In addition to decreasing the afterload on the heart, it may improve visceral organ perfusion thus reducing the severity of multisystem organ failure. Survival is poor for patients who are older, specifically those who are over the age of 65, and who have had a preoperative myocardial infarction, diabetes, decompensated congestive heart failure or cardiogenic shock, and, in our experience, thoracic aortic operations. It is noteworthy that 95% of Doll's patients undergoing aortic valve replacement and coronary bypass grafting and 90% of patients listed in the “other” category (pulmonary embolectomy, ventricular septal defect closure, LV and aortic aneurysm repairs) also succumbed after ECMO support. The more complex the procedure, the less likely the patient will survive. If myocardial recovery is not evident within 48–72 hours, the patient should be assessed for more advanced mechanical circulatory support as more than two thirds of patients who do not survive ECMO support have extensive irreversible myocardial injury. This approach can dramatically improve survival. If the patient is not a candidate for advanced support, is elderly, or has preoperative comorbidities, prolongation of ECMO beyond a few days is not justifiable because survival is very unlikely. ECMO can undoubtedly save the lives of patients requiring postcardiotomy support, but device related complications must be minimized and we need to have realistic expectations for survival.

Prologue: Ventricular assist devices and total artificial hearts: A historical perspective

In the 1960s, when LVADs and TAHs were introduced into clinical use, researchers estimated that, with this technology, the problem of heart failure could be solved within 20 years. Unfortunately, the evolution of these devices has taken much longer than anticipated. Nevertheless, significant advances have been achieved in both cardiac assistance and replacement, and today's cardiac surgeons have a wide range of devices from which to choose (Table 4). This progress has largely been due to the support of the NHLBI, especially the Devices and Technology Division headed by John Watson, and of the devoted commitment of the investigators. Because of the long-term commitment required for both basic and clinical research, commercial medical technology companies are unable to assume this burden. Advances in mechanical circulatory support and replacement have benefited numerous patients worldwide who would otherwise have died of heart failure, and devices now exist for use as bridges to recovery, bridges to transplant, and destination therapy. The current challenge is to refine what we have and to apply these technologies to broader patient populations with maximal safety and at a reasonable cost.

Advanced mechanical circulatory support with the HeartMate left ventricular assist device in the year 2000

This paper describes the HeartMate left ventricular assist device (ThermoCardiosystems Inc, Woburn, MA) technology, which has been successfully introduced into the clinical arena with more than 2,400 implants as of the year 2000. The review summarizes the clinical experience, and identifies the benefits and limitations of the current state-of-the-art technology of the leading implantable circulatory support system.

Transfer of patients receiving advanced mechanical circulatory support

Objective: Improving results with ventricular assist devices have led to their wider clinical application. Centers can stabilize, support, and wean or transfer patients to regional transplant centers. Methods: Prospectively collected data were reviewed to evaluate the clinical results of patients transferred to our institution while receiving advanced mechanical circulatory support. Results: Since 1993, 16 patients were accepted while receiving support with either extracorporeal membrane oxygenation or a ventricular assist device. The 10 male and 6 female patients ranged in age from 9 to 60 years (mean, 42.1 years). Thirteen had had cardiac surgical procedures, two had acute myocardial infarctions, and one had myocarditis. The distance transported ranged from 0.2 to 309 miles (mean, 132 miles). Twelve patients were transferred by ground, and 4 were transported by air. Seven patients were originally supported with extracorporeal membrane oxygenation, 6 with centrifugal pumps, and 3 with ABIOMED ventricular assist devices (ABIOMED, Inc, Danvers, Mass). Two patients had clinical complications during transfer, and one had a cerebrovascular accident, recovered, was weaned, and survived. A second patient had hemodynamic deterioration. There were no technical complications associated with transport. Six patients were left on the original support device; 3 of the 6 were weaned and survived, and 3 died during support. The 10 remaining patients were switched to other ventricular assist devices: 9 patients to Thoratec devices (Thoratec Laboratories, Pleasanton, Calif) and 1 patient to a Novacor device (Baxter Healthcare Corp, Novacor Division, Oakland, Calif). Six of the 10 patients underwent transplantation and survived. Four patients died while being supported by the devices. Nine patients were discharged, with 1 late death at 29 months. Eight patients are alive 4 to 65 months after discharge. Conclusions: These data suggest that patients receiving advanced support can be moved between clinical centers with acceptable risks. Because 33% of the survivors were weaned, transplantation is not required for survival. (J Thorac Cardiovasc Surg 2000;119:1015-20)

Inter-hospital transfer of patients receiving advanced mechanical circulatory support: Lawrence R. McBride, Debra A. Moroney, Paul R. Braun and Marc T. Swartz Saint Louis University, Dept. of Surgery, 3635 Vista at Grand Ave., St. Louis, MO 63110

Inter-hospital transfer of patients receiving advanced mechanical circulatory support: Lawrence R. McBride, Debra A. Moroney, Paul R. Braun and Marc T. Swartz Saint Louis University, Dept. of Surgery, 3635 Vista at Grand Ave., St. Louis, MO 63110

Circulatory support in infants and children

Although the last decade has brought dramatic improvement in patient selection and postoperative management of adults and children undergoing advanced mechanical circulatory support, technological advances have been largely limited to the adult population. Intraaortic balloon pumps are technically feasible, but their efficacy has been questioned and their use has been limited in children. Over the last decade, extracorporeal membrane oxygenation has become the most commonly used method of mechanical circulatory support in children who have severe cardiac failure after cardiac operations. Additionally, a small number of infants and children have been supported with extracorporeal membrane oxygenation as a bridge to cardiac transplantation or as temporary support during reversible myocardial failure due to lesions such as viral myocarditis. More recently, a small number of pediatric patients have been supported with centrifugal and pneumatic devices, particularly after cardiac operations. Surprisingly, many of these patients did well with left ventricular support only. The overall children's survival rates in the myocardial recovery group are better than those in adults. However, current pediatric devices do not provide support for greater than a few weeks, making bridging to transplantation less feasible than in adults.