Mechanical cardiac support 2000: current applications and future trial design: June 15-16, 2000 Bethesda, Maryland

Same Bridge, New Destinations

Mechanical cardiac support with ventricular assist devices is an established therapy for a variety of clinical scenarios, including postcardiotomy shock, "bridge to transplant," and "destination therapy." At present, device development, clinical trial design, regulatory approval, and reimbursement decisions for the clinical application of mechanical cardiac support devices continue to be considered in the context of these clinical indications. Although understandable from a historical perspective, these arbitrary divisions are inconsistent with the clinical realities of advanced heart failure therapy. By narrowly focusing on transplant eligibility at a static point in the clinical course, current guidelines impede the broader application of ventricular assist device technology to the growing population of patients who may benefit from this therapy.

Canadian Cardiovascular Society consensus conference recommendations on heart failure 2006: diagnosis and management

Heart failure remains a common diagnosis, especially in older individuals. It continues to be associated with significant morbidity and mortality, but major advances in both diagnosis and management have occurred and will continue to improve symptoms and other outcomes in patients. The Canadian Cardiovascular Society published its first consensus conference recommendations on the diagnosis and management of heart failure in 1994, followed by two brief updates, and reconvened this consensus conference to provide a comprehensive review of current knowledge and management strategies. New clinical trial evidence and meta-analyses were critically reviewed by a multidisciplinary primary panel who developed both recommendations and practical tips, which were reviewed by a secondary panel. The resulting document is intended to provide practical advice for specialists, family physicians, nurses, pharmacists and others who are involved in the care of heart failure patients. Management of heart failure begins with an accurate diagnosis, and requires rational combination drug therapy, individualization of care for each patient (based on their symptoms, clinical presentation and disease severity), appropriate mechanical interventions including revascularization and devices, collaborative efforts among health care professionals, and education and cooperation of the patient and their immediate caregivers. The goal is to translate best evidence-based therapies into clinical practice with a measureable impact on the health of heart failure patients in Canada.

Different clinical scenarios for circulatory mechanical support in acute and chronic heart failure

Chronic heart failure (HF) is a leading cause of death in developed countries. Over the last 2 decades, mechanical circulatory support (MCS) devices have steadily evolved in the clinical management of end-stage HF and have emerged as a standard of care for the treatment of acute and chronic HF refractory to conventional medical therapy. Possible indications for using MCS are acute cardiogenic shock, as a bridge to transplantation, as a bridge to recovery, and more recently, as destination therapy in dilated cardiomyopathy, of either ischemic or idiopathic etiology. We reviewed the different clinical scenarios in which we think there are currently indications to implant different kinds of MCS systems.

Under-utilization of mechanical circulatory support in Canada: why and what can be done?

In October of 2002, a workshop was held as part of the Canadian Cardiovascular Congress in Edmonton, Canada, entitled "Under-Utilization of Mechanical Circulatory Support in Canada. Why and What Can Be Done?" The workshop examined various issues related to the use of mechanical circulatory support devices in the Canadian context. Representatives from all Canadian centers with active mechanical circulatory support programs were invited to participate and participants included surgeons and cardiologists, as well as other affiliated health professionals. Opinions were solicited from the workshop participants and a series of recommendations were formulated.

Changing Trends in Mechanical Circulatory Assistance:. Experience With 131 Consecutive HeartMate VE Left Ventricular Assist Devices

BACKGROUND

The success of long-term implantable ventricular assist devices has led to their increased use in patients previously thought to be unsuitable for mechanical support. As a result, the demographic profile of patients presenting for LVAD support has changed over time. We reviewed our institutional experience to identify emerging risk factors and changing trends in patients who received the HeartMate VE LVAD.

METHODS

The clinical records were reviewed of 131 consecutive LVAD recipients between 1996 and 2001. All perioperative data were collected prospectively and entered into an institutional database. All patients received a preoperative risk stratification score based upon published criteria. The cohort was arbitrarily divided into early (n = 45), mid (n = 45), and late groups (n = 41).

RESULTS

Overall operative mortality was 25% with no difference between groups. The mean risk score increased significantly over time (early 3.5 +/- 0.4 vs. late 5.3 +/- 0.3, p < 0.05). The proportion of patients at high risk for mortality (score >5) was significantly higher in the late group (51% vs. 29%, p < 0.05). Although ventilation time and ICU stay was similar for all groups, hospital stay was longer in the late group (43 days vs. 23 days, p < 0.05). Mean duration of support fell from 90 to 59 days, but this failed to achieve statistical significance. Out-patient therapy decreased from 73% in the early group to 15% in the late group (p < 0.001). Multivariate analysis identified right heart failure (odds ratio 4.1, 95% CI 2-11) and risk score (OR 1.4, 95% CI 1.2-1.6) as independent predictors of death.

CONCLUSIONS

Despite an increasingly high risk patient population, the mortality associated with LVAD therapy has remained constant. Duration of LVAD support has decreased with a trend toward transplantation before hospital discharge. These data continue to support the aggressive institution of mechanical assistance for acute or chronic heart failure.

Ventricular assist devices: Destination therapy or just another stop on the road?

Ventricular assist devices have attained center-stage recognition with the evolution of the concept of destination therapy, designed as an alternative to cardiac transplantation. However, mechanically induced hemodynamic restoration is accompanied by cellular and biochemical effects that may potentially mediate cardiac recovery. This has raised the fundamental question of whether mechanical assistance is a "failure to grave" option or simply a stop on the road to recovery. The concept of destination therapy as an alternative to transplantation was validated in the Randomized Evaluation of Mechanical Assistance in the Treatment of Congestive Heart Failure trial, but gaps in translating this information to the clinical realm exist because of device limitations of complications and durability. The field of mechanical assistance is progressing rapidly with the introduction of smaller devices that are more durable and have less risk for infection or hematologic aberrancies, which should allow this option to meaningfully enter the clinical arena.

Heart Transplantation at the Ottawa Heart Institute: Comparison with Canadian and International Results

Heart transplantation has been carried out in 340 patients in Ottawa, including seventy-one who required mechanical circulatory support as a bridge to transplant. Survival in Ottawa was compared with other Canadian centers based on data from the Canadian Organ Replacement Register up to the year 2000 and with the International Society of Heart and Lung Transplantation (ISHLT) registry 2001. For survival analysis, the number of adult patients at risk at year 0 was 303 (87 transplanted from 1985 to 1990, 105 from 1990 to 1994, and 111 from 1995 to 2000). The Statistical Analysis System (SAS) life test procedure was used. Survival was not adjusted for comorbidities or heart failure class. For the year of transplant 1985-1989, one-, five-, and ten-year patient survival in Ottawa was 83%, 70%, and 60%, respectively, compared to 82%, 71%, and 54%, respectively, for Canada (Wilcoxon test, P = 0.71), and compared to one- and five-year survival for ISHLT from 1980 to 1987 at 76% and 60%, respectively. For 1990-1994, one-, five-, and ten-year patient survival in Ottawa was 88%, 81%, and 74%, respectively, compared to 80%, 71%, and 61%, respectively, for Canada (P = 0.05), and compared to one- and five-year survival for ISHLT from 1998 to 1992 at 80% and 68%, respectively. For 1995-2000, one- and five-year patient survival in Ottawa was 90% and 82%, respectively, compared to 85% and 76%, respectively, for Canada (P = 0.09), and compared to one- and five-year survival for ISHLT from 1993 to 1996 at 82% and 68%, respectively. Survival after heart transplantation in Ottawa compares favorably with Canadian and international data.

Proposition: the benefit of cardiac transplantation in stable outpatients with heart failure should be tested in a randomized trial

Recent data suggest that cardiac transplantation is associated with a survival benefit only in patients at high risk for dying of advanced heart failure without this procedure. To test the hypothesis that survival and quality of life advantages associated with cardiac transplantation exist in stable outpatients, a 3-stage approach is proposed: 1). to establish a database within the International Society for Heart and Lung Transplantation/United Network for Organ Sharing/Eurotransplant infrastructure that will provide an estimate of the survival benefit of heart transplantation in various heart failure risk strata by prospectively following cohorts of patients listed for heart transplantation; 2). to organize an international consensus conference that will define, based on the review of the Stage 1 data, the feasibility of a prospective randomized trial; and 3). pending consensus, to perform a clinical trial, perhaps with an augmented, randomized design that allocates cardiac transplantation to all patients at high risk for dying of heart failure while randomizing patients at low risk to either conventional treatment or cardiac transplantation. Generating such scientific evidence is important in light of today's donor organ crisis and the associated difficulties of equitable resource allocation.

Emergence of Laplace therapeutics: declaring an end to end-stage heart failure

A large number of chronic heart failure patients escape from the benefits of neurohormonal blockade only to transit into a discouragingly miserable state of what the physician often refers to as end-stage heart failure. Conceptually, the designation of end-stage as a description of a clinical scenario implies pessimism concerning recourse to a therapeutic avenue. A variety of surgical therapeutic techniques that take advantage of the law of Laplace, designed to effectively restore the cardiac shape from a spherical, mechanically inefficient pump to a more elliptical, structurally sound organ are now being employed. Additionally, the field of mechanical device implantation is surging ahead at a rapid pace. The weight of evidence regarding mechanical unloading using assist devices suggests that hemodynamic restoration is accompanied by regression of cellular hypertrophy, normalization of the neuroendocrine axis, improved expression of contractile proteins, enhanced cellular respiratory control, and decreases in markers of apoptosis and cellular stress. Thus, these lines of data point toward discarding the notion of end-stage heart failure. We are at a new crossroad in our quest to tackle chronic heart failure. It is our contention that the use of antiremodeling strategies, including device approaches, will soon signal the end of end-stage heart failure.