The cost of the pumps contributed, in most cases, to the majority of the implant costs and were highest within the PVAD group ($128,656), and lowest within the HMII + CMAG group ($94,500). Costs at the time of implant were greatest within the TAH group ($313,783 ± 203,950) and lowest within the HMII + CMAG group ($222,482 ± 123,798; Figure 3A). However, the large standard deviations prevented any statistical significance. In contrast, despite the large standard deviations, the subsequent re-hospitalization and pump supply costs were significantly greater with the HMII group (Figure 3B, C). Interestingly, the re-hospitalization costs exceeded $100,000 in many cases from within the HMII group over the study period. However, despite greater costs within specific areas, the total costs over the study period were not significantly different between the different pump strategies (PVAD-$306,166 ± 247,839, HMII + CMAG-$278,958 ± 135,324, TAH-$321,387 ± 212477; p = 0.5; Figure 3D).
Variation in costs over the first year of support was identical to the total costs for the TAH and PVAD groups because of the shorter duration of support. From within the HMII group, the average re-hospitalization costs were $19,108 ± 25,678 over the first year, and this group did not incur any equipment charges during the first year. Therefore, there were no significant differences when comparing the total costs at one year (Figure 4).
The use of Bi-V support as a bridge to cardiac transplantation has dramatically changed over the past decade. With constantly changing organ allocation and listing restrictions and regulations,1–5 the ability to transplant patients from Bi-V support devices has dramatically changed. The PVAD group had the shortest wait times and subsequently the highest transplant rate when compared with the HMII and TAH devices. However, PVAD’s were implanted between 2001 and 2006 and benefited from a time where organs could be quickly allocated to those requiring mechanical circulatory support. Data from patients requiring Bi-V support as a bridge to transplant from other groups have demonstrated similar results with close to 50% of patients transplanted after only 100 days of support.8 The majority of those patients remained in the hospital until the time of transplant, and their re-hospitalization costs were low. The supply costs for those patients was limited to pump malfunction shortly after implant, and in part is related to the PVAD as an early generation pump.
The Heartmate II LVAD in conjunction with a CMAG RVAD began the third generation of heart pumps and provided nonpulsatile flow to patients for a longer duration of support. In the majority of cases, the HMII pump is able to provide afterload reduction to the right ventricle, and therefore in the absence of sustained ventricular arrhythmia’s can be explanted within 2–4 weeks. We have previously demonstrated an 88% survival to discharge when using this technique.9 Unfortunately for this group, in the absence of device malfunction, or recurrent arrhythmia it is very difficult to transplant these patients. As a result they had the longest duration of support, and despite having an implant in some patients 5 years earlier, are still listed as a UNOS 1B awaiting transplant. As a consequence the health-care costs associated with this group were some of the highest, in part relating to readmissions for stroke, bleeding, infection, and heart failure. In addition, this increased duration for support also resulted in a significant increase in pump-related supplies after implant.
The TAH system, because of its size requirements,10 was implanted only in men, and therefore this group had a larger body surface area; however, this was not statistically significant. This is similar to the experience of other centers with a larger number of implants, where 85% of patients were male with a mean weight of 88 kg.10 In addition, the TAH was associated with an increased use of ECMO and may in part relate to the overall greatest costs within this population. Although the device itself is more expensive than the HMII, the subsequent readmission, and supply costs were the low. The TAH system is unique in that it allows the surgeon to recover the patient from end-organ dysfunction, discharge the patient home, and then after the patient is stable readmit them to the hospital as a 1AA patient. Therefore, the patient and surgeon must discuss the options in using either a permanent HMII LVAD with temporary RVAD, which may result in longer wait times, or using permanent Bi-V support with the hope of obtaining earlier organ allocation. Therefore, this pump may be optimal in underpopulated areas such as upstate and western New York where the duration to heart transplant may be extend beyond the national average due to limited organ allocation. In contrast, super-populated areas such as southern California, which historically have shorter wait-list times,11 may be less suited to the TAH platform. Longer wait times, may have in part influenced the higher mortality observed from within our population. In many cases, patients were previously listed, and we were unable to obtain a suitable heart for transplant before the patient developed unstable hemodynamics and subsequently requiring Bi-V mechanical circulatory support.
The health-care costs associated Bi-V support as a bridge to cardiac transplant continues to grow. As the technology only improves, the indications for implantation have become less stringent. There is clearly a benefit in the use of Bi-V support as a bridge to cardiac transplant, lowering the transplant mortality, and improving the overall outcomes.1–5 However, the financial impact of these devices is dramatic.12,13 Our costs were lower to previous reports in which isolated LVAD therapy was associated with costs of $1,000.00/day. This may be related to the methods by which costs are calculated, as our definition of cost was related to the cost incurred by the hospital, and not that charged by the hospital. We felt that the costs incurred by the hospital provided a realistic financial metric for the services provided. Hospital charges (money billed to private insurance and Medicare) are a commonly used financial metric, however, charges for the same procedure often vary from hospital to hospital because of differences in charging structure. In addition, charges are only reimbursed at a rate of approximately 25% for Medicare and 38% for private insurance14,15
Unfortunately, based on both the financial metrics and clinical outcomes, there was no clear Bi-V support strategy that demonstrated clear superiority from within this cohort of patients. This suggests that surgeons can freely implant the device they feel most comfortable, without concern that only one strategy results in superior clinical outcomes with limited costs.
This is a retrospective review and therefore has the limitations inherent to that approach. In addition, the Bi-V support for each pump was indicative of a specific era’s both in pump generation, as well as transplant. Certainly, if PVAD support was required beyond one year in the majority of patients, this approach would appear inferior. In contrast, if the HMII + CMAG group and/or the TAH group could be transplanted within months after implant, these results might appear superior. The HMII + CMAG group although received Bi-V support at the time of implantation, the RVAD was weaned and explanted, and therefore, those patients were followed and subsequently transplanted supported only with an LVAD. Finally, these data are representative from one program within an underpopulated area of the United States and may not be reflective of all cardiac transplant centers.
Over the past 15 years, there have been several pump strategies used in the support of Bi-V failure. Despite the variations in Bi-VAD (bi-ventricular assist device) strategy data from our program suggest no significant difference in clinical outcomes between groups. Further, financial data suggest no clear strategy is optimally cost–effective. Therefore, the choice of the Bi-VAD strategy utilized can rest entirely with the surgeon, and their comfort level with each pump, as no one pump demonstrates clear clinical or financial superiority.
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Keywords:Copyright © 2016 by the American Society for Artificial Internal Organs
ventricular assist; cardiac transplant; bi-ventricular assist; mechanical circulatory support