Author + information
- Joseph G. Rogers, MD∗ ( and )
- Christopher M. O’Connor, MD
- Division of Cardiology, Duke University and the Duke Clinical Research Institute, Durham, North Carolina
- ↵∗Reprint requests and correspondence
: Dr. Joseph G. Rogers, Mechanical Circulatory Support and Cardiac Transplant Program, Duke University, Duke University Medical Center, Box 3034 DUMC, Durham, North Carolina 27710.
The past decade has witnessed a rapid evolution in the tools available to treat patients with severe left ventricular systolic dysfunction. Gone are the days of managing advanced heart failure with medical therapy alone. Patients with heart failure who present for tertiary and quaternary cardiovascular care are often those who have received evidence-based medical and electrical therapies but have residual hemodynamic compromise. The intra-aortic balloon pump (IABP), historically used for its relative simplicity, has not withstood the vicissitudes of rigorous clinical trials. The modest hemodynamic support IABP provides has not been associated with survival improvements in either acute myocardial infarction (AMI) or cardiogenic shock (1,2).
As a result, both percutaneous and temporary surgically implanted mechanical circulatory support (MCS) devices are increasingly being used as adjuvant support in high-risk revascularization and ventricular tachycardia ablation procedures and to treat cardiogenic shock. These devices have shown superior hemodynamic improvements relative to IABP, reasonable safety profiles, and similarity to predicate devices. However, a disconnect remains between the hemodynamic benefits of commonly used percutaneous devices and demonstrable outcome improvement in clinical trials (3).
In this issue of the Journal, Stretch et al. (4) describe temporal changes in the utilization and outcomes of patients treated with short-term MCS devices from the National Inpatient Sample, a payer registry consisting of approximately 20% of all U.S. hospitalizations. The authors used billing codes to identify patients treated with either a percutaneously placed or surgically implanted temporary MCS device and stratified patients by era of hospitalization (2004 to 2007 and 2008 to 2011) to examine utilization and outcome trends.
Although it can be difficult to characterize patient populations selected from administrative datasets, important clues in this study highlight the dichotomous use of short-term MCS devices in the United States. One-half of patients in both eras were coded as having cardiogenic shock, and 30% to 40% had a primary diagnosis of AMI. Further, a sizable proportion received an IABP, mechanical ventilation, or cardiopulmonary resuscitation while hospitalized. Conversely, 25% of the patients were electively admitted to the hospital, suggesting that these devices were placed in the context of an elective, invasive cardiac procedure.
The authors demonstrated a dramatic increase (>1,500%) in the use of percutaneous short-term MCS devices from 2007 to 2011, whereas changes in the use of IABP and surgically implanted short-term MCS devices were less marked. This growth in the use of short-term support devices was associated with mortality reductions in the overall cohort and in the subset of patients with cardiogenic shock, as well as with a decrease in length of hospital stay and cost.
Several limitations of this analysis deserve comment. First, the underlying cause for hospitalization in nearly 25% of patients in this series is not classified. As a result, it is difficult to interpret the role of temporary mechanically assisted circulation in distinct patient subsets. Second, the impact of device therapy on mortality reduction was not uniform. When stratified by primary diagnosis, no individual cohort demonstrated statistically significant mortality reductions, and patients with antecedent heart failure and valvular heart disease experienced an increase in mortality suggesting that cardiovascular specialists may be attempting to treat diseases that heretofore were not approached. Going forward, care must be taken to avoid use of temporary MCS devices as a crutch to thoughtful risk stratification and decision making. Third, database analyses as such often do not correct for important patient-specific covariates such as severity and duration of shock, degree of hemodynamic derangement, right ventricular function, renal failure, and other biomarker abnormalities.
Finally, in an era of emphasis on cost containment in medicine, cost effectiveness must be considered in our collective decisions to use various therapies. Although the cost of hospital stays that included implantation of a temporary MCS device was relatively high ($116,858), the authors demonstrate a 22% reduction in hospital costs during the observation period. Similar improvements have been demonstrated in the costs associated with durable MCS devices (5). The reader is provided a myopic view of the overall cost, opportunities, and impact of this support strategy by examining hospital cost in isolation. For example, the discharge-to-home rate increased 50% with concomitant reductions in the use of nonhospital inpatient days. The financial impact of this change must be included in the calculation of overall cost effectiveness. Opportunities such as more rapid implementation of MCS in appropriate patients may reduce delays and avoid ineffective treatments associated with morbidity and prolonged hospital stay. Further, a proportion of these patients will require therapeutic escalation to durable MCS devices or transplant, a cost not considered in this analysis.
A subtle undertone in this paper is worthy of recognition. Increasingly, patients with advanced heart disease are surrounded by integrated teams of cardiologists and surgeons with focused expertise and multimodality therapies that target the clinical needs of this complex population. Considerable gains have been made in improving processes of care for patients with AMI by using a systems engineering and team-based approaches. Similarly, combining revascularization, antitachycardia treatments, and hemodynamic support with contemporary medical therapy has favorably altered the natural history of advanced heart failure.
The cycle of innovation in patient care requires novel insights from astute clinicians, diagnostic and therapeutic advances, thoughtful review of outcomes, and refinement of the approach. The current paper depicts this model, but many questions remain. Who is the right patient for short-term mechanically assisted circulation, and when should the device be implanted? Should other therapies fail first, what criteria should the practitioner use in the decision to insert a temporary device? How long should the device be utilized, and what are the weaning criteria? Although important insights may be gained from registries and observational studies, these questions will best be answered in the context of randomized controlled clinical trials.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Rogers has reported that he has no relationships relevant to the contents of this paper to disclose. Dr. O'Connor has received research funding from Roche Diagnostics, ResMed, and Gilead.
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