- Email: [email protected]
Discharge Outcomes in Patients With Paracorporeal Biventricular Assist Devices
ADULT CARDIAC
Discharge Outcomes in Patients With Paracorporeal Biventricular Assist Devices Sunu S. Thomas, MD, MS, Jennifer Smallwood, MPH, Colleen M. Smith, NP, Leslie M. Griffin, NP, Prem Shekar, MD, Frederick Y. Chen, MD, PhD, Gregory S. Couper, MD, and Michael M. Givertz, MD Cardiovascular Division, Department of Medicine, and Division of Cardiac Surgery, Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
Background. As waiting time for heart transplantation has increased, ventricular assist devices have become critical for “bridging” patients with end-stage heart failure. Because most reported post-discharge experience is with left ventricular assist devices (LVAD), we sought to evaluate the safety and feasibility of home discharge on paracorporeal biventricular assist devices (BIVAD). Methods. We retrospectively reviewed the hospital course and post-discharge outcomes of 46 consecutive patients who received paracorporeal VADs as bridge to transplant. The success of home discharge was assessed by frequency and reasons for hospital readmission and survival to transplant. Results. Thirty patients (65%) were successfully transferred from the intensive care unit and considered candidates for discharge. Of the 26 patients discharged home, 11 were supported with an LVAD and 15 with BIVADs. Median duration of support until transplant,
explant, or death did not differ significantly between LVAD or BIVAD patients (91 days vs 158 days; p [ 0.09). There were 26 readmissions for medical or device-related complications; 10 in 7 LVAD patients and 16 in 10 BIVAD patients, with no difference in median length of stay (17 days vs 25 days; p [ 0.67). Out of hospital duration of support was similar between LVAD and BIVAD patients (61 days vs 66 days; p [ 0.87) as were 6-month and 1-year event-free survival rates (p [ 0.49). Conclusions. Outcomes were similar in patients bridged to transplant on home paracorporeal BIVAD versus LVAD support. We recommend discharge for stable patients demonstrating device competency and adequate home care regardless of the need for univentricular or biventricular paracorporeal support. (Ann Thorac Surg 2014;97:894–900) Ó 2014 by The Society of Thoracic Surgeons
V
portable pneumatic driver has allowed greater mobility, improved quality of life, and discharge home [7]. Recent data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) reflect the increasing number and types of VADs being implanted in the United States, as well as the increasing number of implanting centers [8]. The challenge, however, for those patients in whom VADs are used as a bridge to transplant, is the continued shortage of organ donors [9]. For the growing number of patients awaiting cardiac transplant, the need for increased patient independence post VAD is amplified. Home discharge options become paramount for the patient and family, as well as for health care institutions that must bear the costs associated with VAD-related hospitalization. In this study, we reviewed our experience with home discharge outcomes in patients implanted with paracorporeal biventricular assist devices (BIVADs) and compared them to those with paracorporeal LVADs. Our aim was to evaluate the safety and efficacy of home paracorporeal BIVAD support.
entricular assist devices (VADs) have proven to be an effective mechanical circulatory support strategy to promote survival in patients with end-stage heart failure [1, 2]. From their initial historical use for post cardiotomy shock, VAD indications have evolved to include cardiogenic shock, bridge to recovery, and longterm support for destination therapy or bridge to heart transplant [3]. Ventricular assist devices may be implanted to provide univentricular or biventricular support depending on the severity of hemodynamic compromise and end-organ failure, likelihood of recovery, and potential for cardiac transplant. The vast majority of durable VADs in current use provide isolated left ventricular support (LVAD) [4]. More recently, the total artificial heart (TAH; SynCardia Systems Inc, Tucson, AZ) has provided a mechanical option for patients with biventricular failure as a bridge to transplant [5, 6]. Some patients, however, receive paracorporeal VADs due to small body size, medical or surgical contraindications to implantable VADs, or surgeon preference. For these patients, the availability of a
Patients and Methods Accepted for publication Oct 1, 2013. Address correspondence to Dr Givertz, Cardiovascular Division, Brigham and Women’s Hospital, 75 Francis St, Boston, MA 02115; e-mail: [email protected].
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
Patient Selection We performed a retrospective medical record review of all patients who underwent surgical placement of a 0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2013.10.019
paracorporeal LVAD or BIVAD (Thoratec Corporation, Pleasanton, CA) as a bridge to cardiac transplant at our center between February 2004 and September 2009. This study was conducted with the approval of the Brigham and Women’s Hospital Human Research Committee for review of medical records. Individual patient consent was not required as the analysis was performed using de-identified data. Mechanical circulatory support was offered to patients with severe refractory heart failure due to a nonischemic cardiomyopathy attributed to viral, valvular, familial or idiopathic etiologies, or an ischemic cardiomyopathy resulting from prior myocardial infarction or related to percutaneous or surgical coronary revascularization. The acuity of each patient’s clinical presentation and urgency for mechanical circulatory support was classified according to INTERMACS profiles [10]. Left ventricular versus biventricular support was a surgical decision based on severity of right ventricular dysfunction determined by hemodynamics, echocardiography, and endorgan function. Patients implanted with temporary or isolated long-term right ventricular paracorporeal devices were excluded from the analysis.
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
895
component of postoperative care as the majority of patients were malnourished prior to VAD implantation. Adequate caregiver support was considered crucial for successful discharge. Patients needed to identify at least 1 and ideally 2 caregivers to be available for assistance and to learn about device management. The training program was gradual, with daily sessions geared to the patient’s learning ability. In addition, caregivers met with a VAD nurse practitioner for at least 3 1-hour sessions. Before patients were eligible for discharge, they and their caregivers were required to demonstrate competency maintaining a logbook of VAD parameters, daily weights and vital signs, and with sterile wound care technique. They were also required to demonstrate a full knowledge in troubleshooting VAD alarms, and the ability to handpump the VAD and switch to a back-up portable driver.
Additional Support
The primary outcome of this study was the proportion of patients who were discharged home with a VAD. Additional outcomes included duration of VAD support, out-of-hospital time with the VAD, number of VAD complications, and hospital readmissions, with the exclusion of admissions for heart transplant, back-up call for a donor heart, device weaning, and desensitization. Event-free survival was defined as survival free of death, heart transplant, or device explant due to myocardial recovery.
A dedicated social worker played an active role in assisting patients and families in identifying support systems and adjusting to their illness. In addition, a VAD support group for patients living on mechanical circulatory support was initiated to foster emotional and social support and discuss strategies needed to manage living on a VAD. Community support and education were provided by the VAD nurse practitioners, who traveled to the patient’s communities and educated first responders, local physicians, emergency room staff, visiting nurses, and other family members and friends on device function and care. In particular, emergency troubleshooting for device problems was reviewed in detail, and a specific plan for local emergency response utilizing both air and ground transportation was arranged. After discharge, visiting nurses were responsible for wound care until the patient’s primary caregiver took over the responsibility. For 2 weeks after discharge, the caregiver was required to provide constant supervision. After this time, the amount of supervision was left to the discretion of the patient and family. Routine visits were scheduled and all patients were seen by a surgeon, cardiologist, and nurse practitioner 2 weeks after discharge, and then monthly in the outpatient VAD clinic. Nurse practitioners also maintained regular phone contact.
Medical Management
Statistical Analysis
All patients were treated with aspirin, dipyridamole, and warfarin dosed to a target international normalized ratio of 2.5 to 3.5. Diuretics and anti-hypertensive agents were used as needed to treat edema and hypertension, respectively. During this period we did not routinely institute comprehensive neurohormonal blockade with angiotensin-converting enzyme inhibitors, beta-blockers, and aldosterone antagonists unless there was potential for myocardial recovery. Once transferred out of the ICU, patients worked daily with physical and occupational therapy to build the necessary strength and endurance for home ambulation and independence with activities of daily living. Nutrition consultation was also a key
Statistical analyses were carried out using SAS version 9.2 (SAS Institute, Cary, NC). Descriptive statistics are reported as percentages, means standard error of the mean, and medians with interquartile range [25% to 75%]. The p values were calculated using the Wilcoxon rank-sum test for continuous variables and the c2 test for categorical values. In the instance where expected values in the contingency tables were below 5, p values were calculated using the Fisher exact test. Hazard ratios and Kaplan-Meier survival analyses were generated using MedCalc software version 12.2.1.0 (Mariakerke, Belgium). Censoring events included cardiac transplant or device explant for myocardial recovery.
Discharge Eligibility Patients were deemed discharge eligible upon successful transfer from the cardiac surgical intensive care unit (ICU) to the step-down unit after VAD implantation. Only those patients who were on a stable outpatient medical regimen, having successfully completed a comprehensive education program on VAD function and troubleshooting, and with appropriate social support, were discharged home [11].
Outcomes
ADULT CARDIAC
Ann Thorac Surg 2014;97:894–900
896 ADULT CARDIAC
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
Ann Thorac Surg 2014;97:894–900
Table 1. Baseline Characteristics of Patients With Paracorporeal Ventricular Assist Devices Characteristic Age, years Sex, n (%) Male Female Cardiomyopathy, n (%) Ischemic Non-ischemic LVEF INTERMACS profile, n (%) 1 2 3 or higher Positive inotropes, n (%) BUN, mg/dL Creatinine, mg/dL ALT, U/L, median [IQR] AST, U/L, median [IQR] Albumin, g/dL Hematocrit, % Platelet count, x1000/mL INR
LVAD (n ¼ 20)
BIVAD (n ¼ 26)
p Value
52 4
48 3
0.50
13 (65) 7 (35)
13 (50) 13 (50)
0.31
5 (25%) 15 (75%) 0.19 0.04
6 (23%) 20 (77%) 0.15 0.02
0.88
4 (20) 10 (50) 6 (30) 16 (80) 30 2 1.4 0.1 51 (20–108) 39 (29–401) 3.5 0.1 33 1 224 20 1.7 0.2
10 (38) 11 (42) 5 (19) 25 (96) 43 5 1.6 0.1 74 (19–274) 58 (25–129) 3.3 0.1 33 1 216 19 1.7 0.1
0.15
0.41
0.18 0.06 0.40 0.35 0.44 0.33 0.94 0.74 0.99
ALT ¼ alanine aminotransferase; AST ¼ aspartate aminotransferase; BIVAD ¼ biventricular assist device; BUN ¼ blood urea nitrogen; INR ¼ international normalized ratio; INTERMACS ¼ Interagency Registry for Mechanically Assisted Circulatory Support; IQR ¼ interquartile range; LVAD ¼ left ventricular assist device; LVEF ¼ left ventricular ejection fraction.
Results Patient Population Between February 2004 and September 2009, 47 patients with end-stage heart failure underwent implantation of a Thoratec paracorporeal VAD as a bridge to transplant. Of these, 20 patients received an LVAD, 26 required BIVADs, and 1 patient was excluded after having received an isolated right ventricular assist device. In the entire cohort, 57% of patients were male and 76% had a nonischemic cardiomyopathy. There were no significant differences in baseline characteristics between LVAD and BIVAD patients (Table 1), except for a trend toward higher blood urea nitrogen in the BIVAD group. Comorbidities included anemia, renal dysfunction, and poor nutrition. Most patients were in INTERMACS profile 1 (30%) or 2 (46%) at the time of VAD implantation.
ICU Transfer, Hospital Discharge, and Home Support Thirty patients (64%) were successfully transferred from the ICU to the step-down unit, and considered potential discharge candidates. Twenty-six (87%) of these patients were successfully discharged home (Table 2). The BIVAD patients tended to have a longer median hospital length of stay (BIVAD 54 days [37 to 74]; LVAD 33 days [27 to 38]; p ¼ 0.05). The overall home discharge rate for LVAD and BIVAD patients was not significantly different (58% and 55%, respectively; p ¼ 0.79). Four discharge eligible candidates (1 LVAD, 3 BIVAD) remained hospitalized for medical or psychosocial reasons. Of the 16 patients who were not candidates for discharge, 13 (28% of the total
cohort) died in the ICU. For discharged patients, the median support time did not differ between LVAD and BIVAD patients (61 days [37 to 107] and 66 days [24 to 119], respectively; p ¼ 0.84) with a maximum duration of home LVAD support of 517 days and BIVAD support of 221 days.
Readmissions After hospital discharge, there were 26 readmissions for medical or device-related complications, including 10 admissions in 7 LVAD patients and 16 admissions in 10 BIVAD patients. The complication event rates did not differ significantly between the 2 groups (Table 3). The median time to first readmission post discharge was 39 days [32 to 65] in patients with LVADs and 16 days [9 to 16] in those with BIVADs (p ¼ 0.29) (Table 2). The median length of stay for readmissions did not differ between the groups (LVAD, 3 days [0 to 17]; BIVAD, 9 days [0 to 45]; p ¼ 0.67). The most common reasons for readmission included device failure or alarms, driveline complications, and gastrointestinal and neurologic events (Table 3). The maximum number of readmissions experienced by any LVAD patient was 4 and 2 BIVAD patients had 3 readmissions each. Of the 17 patients with medical or device-related complications, 12 survived to transplant and 5 died.
Device-Related Readmissions Of the 26 readmissions for complications, 9 (35%) were device related. Device malfunction was the cause of readmission in 6 patients. Two patients (1 LVAD, 1
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
897
Table 2. Paracorporeal Ventricular Assist Device Outcomes Variable
LVAD
BIVAD
All patients: Implant admission, n (%) Discharge to home Discharge eligible in-hospital Discharge ineligible ICU death Survival Patients discharged home Outcome, n (%) Transplant Death Explant Implant to transplant/death/explant, days Implant to discharge, days Discharge to first readmission, days Device/medical readmissions per patient, n LOS for device/medical complication, days Out-of-hospital duration, days
n ¼ 20
n ¼ 26
11 (55) 1 (5) 2 (10) 6 (30) 11 (55) n ¼ 11
15 (58) 3 (11) 1 (4) 7 (27) 16 (62) n ¼ 15
8 3 0 91 33 39 1 3 61
(73) (27) (0) (81–152) (27–38) (32–65) (0–1) (0–17) (37–107)
12 2 1 158 54 16 1 9 66
p Value
0.79
0.61
(80) (13) (7) (131–199) (37–74) (9–67) (0–2) (0–45) (24–119)
0.78
0.09 0.05 0.29 0.56 0.67 0.84
Data reported as median with interquartile range unless otherwise stated. BIVAD ¼ biventricular assist device;
ICU ¼ intensive care unit;
BIVAD) experienced loss of sensor function and it was deemed unsafe to have them at home with their fill alarm silenced and operating in fixed mode. A third patient was at home on BIVAD support and lost the fill signal on the right VAD. Adequate LVAD decompression could not be maintained on the portable driver and the patient was maintained in the hospital on the dual drive console until transplant. An additional LVAD patient also experienced loss of the fill signal and remained in the hospital until transplant. Driveline complications occurred in 3 paracorporeal BIVAD patients. One patient was readmitted with an abdominal wound infection and required treatment with
LOS ¼ length of stay;
LVAD ¼ left ventricular assist device.
intravenous antibiotics. Two other patients were successfully managed at home with oral antibiotics.
Medical Complications Non-device related medical complications accounted for 17 readmissions. Of these, 6 (35%) were the result of neurologic events occurring in 4 patients. One LVAD patient accounted for 2 strokes and a seizure associated with a cardiac arrest. Two BIVAD patients suffered strokes and 1 LVAD patient presented with diplopia. Of this group, only 1 LVAD patient survived to transplant. Other medical reasons for readmission included symptomatic volume overload, ventricular arrhythmias,
Table 3. Paracorporeal Ventricular Assist Device Hospital Readmissions LVAD (n ¼ 11) Variable Patients with readmissions Overall readmissions Device-specific Malfunction/failure Driveline complication Medical-related Cardiac Infection Gastrointestinal Hematologic Neurologic BIVAD ¼ biventricular assist device;
n (%) 7 10 1 1 0 9 1 2 0 2 4
(63.6) (100) (10.0) (10.0) (0.0) (90.0) (10.0) (20.0) (0.0) (20.0) (40.0)
Events Per Patient Year 1.59 2.27 0.23 0.23 0.00 2.05 0.23 0.45 0.00 0.45 0.91
LVAD ¼ left ventricular assist device.
BIVAD (n ¼ 15) n (%) 10 16 8 5 3 8 0 2 2 2 2
(66.7) (100) (50.0) (13.3) (18.8) (50.0) (0.0) (12.5) (12.5) (12.5) (12.5)
Events Per Patient Year
p Value
1.45 2.32 1.16 0.73 0.44 1.16 0.00 0.16 0.29 0.29 0.29
0.85 0.96 0.09 0.26 0.17 0.24 0.21 0.65 0.26 0.65 0.17
ADULT CARDIAC
Ann Thorac Surg 2014;97:894–900
898 ADULT CARDIAC
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
Ann Thorac Surg 2014;97:894–900
bacterial and viral infection, acute cholecystitis, and druginduced hemolytic anemia (in 2 BIVAD patients).
Overall Outcomes By Kaplan Meier analysis, event-free survival was not significantly different between LVAD and BIVAD patients at 30 days, 6 months, and 1 year after device implantation (p ¼ 0.52) (Fig 1). Of the 26 device patients discharged home, 20 (77%) were successfully transplanted, 5 (19%) died, and 1 underwent VAD weaning and device explant (Table 2). Among patients either eligible for discharge or discharged home, there was also no significant difference in event-free survival between LVAD and BIVAD patients at 30 days, 6 months, or 1 year after device implantation (p ¼ 0.35), (Fig 2).
Comment In this single-center study, we describe our experience with paracorporeal VADs and demonstrate that patients with BIVADs have similar post discharge outcomes as those with left ventricular support only. With comparable numbers and types of readmissions, and similar survival at 6 months and 1 year, our data support the recommendation that both LVAD and BIVAD patients can live at home safely on a portable driver while awaiting heart transplant. After discharge, we observed no difference in the rates or types of hospital readmissions experienced by either VAD type. The most common reasons for readmission were stroke, device malfunction, and infection. As demonstrated in prior experiences with the Thoratec paracorporeal VAD and other pulsatile LVADs [12–14], thromboembolic events contributed to significant morbidity and mortality, including 3 deaths. All patients were maintained on combination antiplatelet and
Fig 1. Event-free survival after device implantation. There were no differences in Kaplan-Meier survival estimates between LVAD or BIVAD patients at 30 days (LVAD 78.9 [0.09], BIVAD 72.7 [0.09]); 6 months (LVAD 58.3 [0.13], BIVAD 60.0 [0.11]); or 1 year (LVAD 19.4 [0.16], BIVAD 51.4 [12]) (p ¼ 0.52). Hazard ratio 0.75; 95% CI 0.30 to 1.88. (BIVAD ¼ biventricular assist device; CI ¼ confidence interval; LVAD ¼ left ventricular assist device.)
Fig 2. Paracorporeal device survival contingent on discharge eligibility. There were no differences in Kaplan-Meier survival estimates between LVAD or BIVAD patients at 30 days (LVAD 91.7 [0.08], BIVAD 100 [0.0]; 6 months (LVAD 78.6 [0.14], BIVAD 82.5 [0.12]; or at 1 year (LVAD 39.3 [0.29]; BIVAD 71.7 [0.15]) after device implantation (p ¼ 0.35). Hazard ratio 0.50; 95% CI 0.09 to 2.73. (BIVAD ¼ biventricular assist device; CI ¼ confidence interval; LVAD ¼ left ventricular assist device.)
anticoagulation therapy, and international normalized ratios were therapeutic at the time of the events. While underlying infection may predispose to cerebrovascular events in VAD patients [15, 16], we observed active infection in only 1 patient at the time of stroke. Duration of out-of-hospital VAD support averaged 61 days for LVAD patients and 66 days for BIVAD patients, which is comparable with previously published experiences [17, 18]. Device failure was not found to be a serious complication in patients discharged home on the portable driver, although it did necessitate readmission and alteration in device settings. Notably, all patients with device malfunction went on to successful cardiac transplant, indicating that device failure did not significantly increase morbidity. However, inpatient monitoring was felt to be necessary for patient safety. Although VAD mechanical dysfunction was not life threatening in our patients, quality control issues associated with the portable driver proved to be a negative aspect of the “bridge” experience. With medium- to long-term outpatient use, components of the system, including cables, batteries, and the drivers themselves, needed to be replaced. During the observation period, there was a US Food and Drug Administration recall in which certain drivers needed to be returned to the manufacturer. In several instances we erred on the side of safety and kept patients hospitalized until transplant. Patients requiring biventricular support are typically critically ill at the time of implantation (eg, INTERMACS profile 1 and 2). In our cohort, we did not observe significant baseline differences in LVAD and BIVAD patients, but this may reflect small patient numbers as there were trends toward greater inotrope use, higher blood urea nitrogen, and lower average INTERMACS
profiles in the BIVAD group. Event-free survival was similar in LVAD and BIVAD patients, with rates comparable with previous studies [17, 18]. A recent INTERMACS analysis found that BIVAD patients were more critically ill with greater morbidity and mortality than LVAD patients [19]. These data may differ from ours due to the larger sample size and greater acuity of the BIVAD population in INTERMACS. In contrast, indices of end-organ function were similar and reasonably preserved in our patients with either BIVAD or LVAD support. Among published studies, the number of patients implanted and discharged home with BIVADs is few [17, 18]. The 15 BIVAD patients discharged from our institution represent a relatively large single-center experience. While paracorporeal VADs had previously been the predominant mechanical circulatory support strategy for patients awaiting cardiac transplant [20], recent data [8] show that these numbers have significantly diminished due to limitations in durability, complications including infection, and barriers to discharge. This has led to the emergence of alternative types of biventricular support, including the TAH. However, paracorporeal VADs remain the preferred strategy when TAH candidacy is constrained by small body size, or lack of institutional experience or availability. Recently, the Reflection Group on Mechanical Circulatory Support reported similar overall patient survival with TAH and implantable or paracorporeal BIVADs [21]. However, when device support extended beyond 90 days, survival was greater with TAH, with a lower incidence of neurologic events. While we could not compare home paracorporeal BIVAD outcomes with TAH patients, future data from the SynCardia TAH freedom driver study (clinicaltrials.gov, NCT00733447) should help to inform these comparisons. More recently, the use of a bilateral continuous flow pump system consisting of HeartWare HVADs (Framingham, MA) has emerged as another potential option for patients requiring biventricular support. The smaller size (162 g) and intrapericardial implantation of the HVAD pump facilitates use in patients who would otherwise be ineligible for a total artificial heart. A recent report observed an 82% 30-day survival rate, with more than 50% of patients discharged home [22]. At our institution, discharge eligibility is dependent upon the establishment of specific patient, caregiver, and support network contingencies that ensure the greatest likelihood for outcome success. Competence in device maintenance, including driveline care and device alarm recognition and interpretation, are prerequisites for discharge. In addition to close clinic and telephone follow-up, our multidisciplinary VAD team also extends to a community-based network of providers, including first responders, local primary care physicians, and emergency room clinicians who may be involved in patient care. While there can be strong institutional motivations to discharge VAD patients, the anticipated psychologic, social, and emotional adjustments for patients and their caregivers cannot be underestimated, and may be further
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
899
amplified by the need for biventricular support. We based our study and its conclusions on the assumption that patients prefer to be at home while awaiting transplant [23]. However, some patients felt extremely anxious about being discharged, and this was a frequent focus of discussion in the VAD support group. Factors such as reduced proximity to knowledgeable health care professionals and fear of device malfunction added significantly to predischarge anxiety. Additional stressors included adjustments to activities of daily living, living space modifications, and maintenance of social and sexual relations [24]. A few limitations are inherent in our study. First, the retrospective design and small sample size make it difficult to draw strong conclusions. Further prospective studies with larger numbers of patients from multiple centers are needed. Beyond assessing survival, additional analyses are necessary to compare quality of life before and after discharge. The choice of a paracorporeal LVAD versus BIVAD was a clinical decision made in patients with significant hemodynamic compromise. While risk scores for right heart failure were considered [25], they did not dictate device choice. In summary, we demonstrated the safety and efficacy of home paracorporeal biventricular assist in patients with end-stage heart disease. While significant risks with this strategy exist, outcomes were not different compared with patients bridging to transplant on paracorporeal LVADs. With comprehensive patient and caregiver education, discharge for medically stable patients demonstrating device competency and adequate home support is feasible and should be offered regardless of the need for paracorporeal univentricular or biventricular support.
References 1. Rose EA, Gelijns AC, Moskowitz AJ, et al. Long-term mechanical left ventricular assistance for end-stage heart failure. N Engl J Med 2001;345:1435–43. 2. Slaughter MS, Rogers JG, Milano CA, et al. Advanced heart failure treated with continuous-flow left ventricular assist device. N Engl J Med 2009;361:2241–51. 3. Karamlou T, Gelow J, Diggs BS, et al. Mechanical circulatory support pathways that maximize post-heart transplant survival. Ann Thorac Surg 2013;95:480–5. 4. Kirklin JK, Naftel DC, Kormos RL, et al. The Fourth INTERMACS Annual Report: 4,000 implants and counting. J Heart Lung Transplant 2012;31:117–26. 5. Copeland JG, Smith RG, Arabia FA, et al. Cardiac replacement with a total artificial heart as a bridge to transplantation. N Engl J Med 2004;351:859–67. 6. Copeland JG, Copeland H, Gustafson M, et al. Experience with more than 100 total artificial heart implants. J Thorac Cardiovasc Surg 2012;143:727–34. 7. Farrar DJ, Buck KE, Coulter JH, Kupa EJ. Portable pneumatic biventricular driver for the Thoratec ventricular assist device. ASAIO J 1997;43:M631–4. 8. Kirklin JK, Naftel DC, Kormos RL, et al. Fifth INTERMACS annual report: risk factor analysis from more than 6,000 mechanical circulatory support patients. J Heart Lung Transplant 2013;32:141–56. 9. Givertz MM. Heart allocation in the United States: intended and unintended consequences. Circ Heart Fail 2012;5:140–3.
ADULT CARDIAC
Ann Thorac Surg 2014;97:894–900
900 ADULT CARDIAC
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
10. Stevenson LW, Pagani FD, Young JB, et al. INTERMACS profiles of advanced heart failure: the current picture. J Heart Lung Transplant 2009;28:535–41. 11. Wilson SR, Givertz MM, Stewart GC, Mudge GH Jr. Ventricular assist devices: the challenges of outpatient management. J Am Coll Cardiol 2009;54:1647–59. 12. Farrar DJ. The Thoratec ventricular assist device: a paracorporeal pump for treating acute and chronic heart failure. Semin Thorac Cardiovasc Surg 2000;12:243–50. 13. Kirsch M, Vermes E, Damy T, et al. Single-centre experience with the Thoratec paracorporeal ventricular assist device for patients with primary cardiac failure. Arch Cardiovasc Dis 2009;102:509–18. 14. Brehm K, Heilmann C, Siepe M, Benk C, Beyersdorf F, Schlensak C. Thoratec paracorporeal biventricular assist device therapy: the Freiburg experience. Eur J Cardiothorac Surg 2012;41:207–12. 15. Tsukui H, Abla A, Teuteberg JJ, et al. Cerebrovascular accidents in patients with a ventricular assist device. J Thorac Cardiovasc Surg 2007;134:114–23. 16. Aggarwal A, Gupta A, Kumar S, et al. Are blood stream infections associated with an increased risk of hemorrhagic stroke in patients with a left ventricular assist device? ASAIO J 2012;58:509–13. 17. Slaughter MS, Sobieski MA, Martin M, Dia M, Silver MA. Home discharge experience with the Thoratec TLC-II portable driver. ASAIO J 2007;53:132–5.
Ann Thorac Surg 2014;97:894–900
18. Oosterom A, de Jonge N, Kirkels JH, et al. End-stage heart failure and mechanical circulatory support: feasibility of discharge from hospital. Neth Heart J 2007;15:45–50. 19. Cleveland JC Jr, Naftel DC, Reece TB, et al. Survival after biventricular assist device implantation: an analysis of the Interagency Registry for Mechanically Assisted Circulatory Support database. J Heart Lung Transplant 2011;30:862–9. 20. Berman M, Parameshwar J, Jenkins DP, et al. Thoratec implantable ventricular assist device: the Papworth experience. J Thorac Cardiovasc Surg 2010;139:466–73. 21. Kirsch M, Mazzucotelli JP, Roussel JC, et al. Survival after biventricular mechanical circulatory support: does the type of device matter? J Heart Lung Transplant 2012;31:501–8. 22. Krabatsch T, Potapov E, Stepanenko A, et al. Biventricular circulatory support with two miniaturized implantable assist devices. Circulation 2011;124(11 Suppl):S179–86. 23. Marcuccilli L, Casida JJ, Peters RM, Wright S. Sex and intimacy among patients with implantable left-ventricular assist devices. J Cardiovasc Nurs 2011;26:504–11. 24. Grady KL, Meyer PM, Dressler D, et al. Longitudinal change in quality of life and impact on survival after left ventricular assist device implantation. Ann Thorac Surg 2004;77:1321–7. 25. Matthews JC, Koelling TM, Pagani FD, Aaronson KD. The right ventricular failure risk score: a pre-operative tool for assessing the risk of right ventricular failure in left ventricular assist device candidates. J Am Coll Cardiol 2008;51: 2163–72.
INVITED COMMENTARY Congratulations to the authors [1]. It is refreshing to find an article in the field of mechanical circulatory support that is scientifically sound and honestly presents a contemporary experience that challenges the current wave of enthusiasm for supporting everyone with continuous-flow left ventricular assist devices (LVADs). This experience is exclusively with pulsatile paracorporeal devices, LVADs and biventricular assist devices (BIVADs). The BIVADs are assist, not replacement, devices. The authors selected BIVAD support preemptively in over half of their patient population and did equally well with the BIVAD group as with the LVADs, even though there was a consistent trend for BIVAD patients to be sicker before implantation (blood urea nitrogen levels higher, INTERMACS [Interagency Registry for Mechanically Assisted Circulatory Support] status sicker, more use of inotropic agents, ejection fraction lower). The patient population was fairly homogeneous, with 80% having INTERMACS status 1 or 2, 75% having nonischemic heart failure, and all being candidates for transplantation. Device selection was surgical: “Left ventricular versus biventricular support was a surgical decision determined by hemodynamics, echocardiography, and end-organ function.” The risk scores for right ventricular failure did not dictate the choice of device. I have to agree that this should be a surgical decision and that risk scores should never dictate a final clinical decision. In this study there were 20 LVADs and 26 BIVADs. Right ventricular failure was recognized and addressed by BIVAD implantation. The authors offer hope for patients in right heart failure who need a BIVAD, and they offer knowhow for those seeking to discharge these arguably more complicated patients. Survival results
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
“overall” and “contingent upon discharge eligibility” were similar for the LVAD and BIVAD groups. The home discharge rate of nearly 60%, the readmission rates, and the adverse event rates were all comparable. This, for the BIVAD group, is amazing. I am unaware of any other report of outpatient BIVAD, external or implantable, pulsatile or nonpulsatile, that presents equal results. A large part of the success of outpatient BIVAD support in this study no doubt resulted from education of the patient and family, good communication, and excellent medical and psychological care. Thus, the authors and their team in a highly credible institution have documented the need for and usefulness of BIVADs and the possibility of hospital discharge of patients with BIVADs. Dr Copeland discloses a financial relationship with SynCardia Systems, Inc. Jack Copeland, MD Department of Surgery UC San Diego 9444 Medical Center Dr 3-020 ECOB 3rd Flr La Jolla, CA 85724-507 192037 e-mail: [email protected]
Reference 1. Thomas SS, Smallwood J, Smith CM, et al. Discharge outcomes in patients with paracorporeal biventricular assist devices. Ann Thorac Surg 2014;97:894–900.
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2013.10.020
Discharge Outcomes in Patients With Paracorporeal Biventricular Assist Devices Sunu S. Thomas, MD, MS, Jennifer Smallwood, MPH, Colleen M. Smith, NP, Leslie M. Griffin, NP, Prem Shekar, MD, Frederick Y. Chen, MD, PhD, Gregory S. Couper, MD, and Michael M. Givertz, MD Cardiovascular Division, Department of Medicine, and Division of Cardiac Surgery, Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
Background. As waiting time for heart transplantation has increased, ventricular assist devices have become critical for “bridging” patients with end-stage heart failure. Because most reported post-discharge experience is with left ventricular assist devices (LVAD), we sought to evaluate the safety and feasibility of home discharge on paracorporeal biventricular assist devices (BIVAD). Methods. We retrospectively reviewed the hospital course and post-discharge outcomes of 46 consecutive patients who received paracorporeal VADs as bridge to transplant. The success of home discharge was assessed by frequency and reasons for hospital readmission and survival to transplant. Results. Thirty patients (65%) were successfully transferred from the intensive care unit and considered candidates for discharge. Of the 26 patients discharged home, 11 were supported with an LVAD and 15 with BIVADs. Median duration of support until transplant,
explant, or death did not differ significantly between LVAD or BIVAD patients (91 days vs 158 days; p [ 0.09). There were 26 readmissions for medical or device-related complications; 10 in 7 LVAD patients and 16 in 10 BIVAD patients, with no difference in median length of stay (17 days vs 25 days; p [ 0.67). Out of hospital duration of support was similar between LVAD and BIVAD patients (61 days vs 66 days; p [ 0.87) as were 6-month and 1-year event-free survival rates (p [ 0.49). Conclusions. Outcomes were similar in patients bridged to transplant on home paracorporeal BIVAD versus LVAD support. We recommend discharge for stable patients demonstrating device competency and adequate home care regardless of the need for univentricular or biventricular paracorporeal support. (Ann Thorac Surg 2014;97:894–900) Ó 2014 by The Society of Thoracic Surgeons
V
portable pneumatic driver has allowed greater mobility, improved quality of life, and discharge home [7]. Recent data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) reflect the increasing number and types of VADs being implanted in the United States, as well as the increasing number of implanting centers [8]. The challenge, however, for those patients in whom VADs are used as a bridge to transplant, is the continued shortage of organ donors [9]. For the growing number of patients awaiting cardiac transplant, the need for increased patient independence post VAD is amplified. Home discharge options become paramount for the patient and family, as well as for health care institutions that must bear the costs associated with VAD-related hospitalization. In this study, we reviewed our experience with home discharge outcomes in patients implanted with paracorporeal biventricular assist devices (BIVADs) and compared them to those with paracorporeal LVADs. Our aim was to evaluate the safety and efficacy of home paracorporeal BIVAD support.
entricular assist devices (VADs) have proven to be an effective mechanical circulatory support strategy to promote survival in patients with end-stage heart failure [1, 2]. From their initial historical use for post cardiotomy shock, VAD indications have evolved to include cardiogenic shock, bridge to recovery, and longterm support for destination therapy or bridge to heart transplant [3]. Ventricular assist devices may be implanted to provide univentricular or biventricular support depending on the severity of hemodynamic compromise and end-organ failure, likelihood of recovery, and potential for cardiac transplant. The vast majority of durable VADs in current use provide isolated left ventricular support (LVAD) [4]. More recently, the total artificial heart (TAH; SynCardia Systems Inc, Tucson, AZ) has provided a mechanical option for patients with biventricular failure as a bridge to transplant [5, 6]. Some patients, however, receive paracorporeal VADs due to small body size, medical or surgical contraindications to implantable VADs, or surgeon preference. For these patients, the availability of a
Patients and Methods Accepted for publication Oct 1, 2013. Address correspondence to Dr Givertz, Cardiovascular Division, Brigham and Women’s Hospital, 75 Francis St, Boston, MA 02115; e-mail: [email protected].
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
Patient Selection We performed a retrospective medical record review of all patients who underwent surgical placement of a 0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2013.10.019
paracorporeal LVAD or BIVAD (Thoratec Corporation, Pleasanton, CA) as a bridge to cardiac transplant at our center between February 2004 and September 2009. This study was conducted with the approval of the Brigham and Women’s Hospital Human Research Committee for review of medical records. Individual patient consent was not required as the analysis was performed using de-identified data. Mechanical circulatory support was offered to patients with severe refractory heart failure due to a nonischemic cardiomyopathy attributed to viral, valvular, familial or idiopathic etiologies, or an ischemic cardiomyopathy resulting from prior myocardial infarction or related to percutaneous or surgical coronary revascularization. The acuity of each patient’s clinical presentation and urgency for mechanical circulatory support was classified according to INTERMACS profiles [10]. Left ventricular versus biventricular support was a surgical decision based on severity of right ventricular dysfunction determined by hemodynamics, echocardiography, and endorgan function. Patients implanted with temporary or isolated long-term right ventricular paracorporeal devices were excluded from the analysis.
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
895
component of postoperative care as the majority of patients were malnourished prior to VAD implantation. Adequate caregiver support was considered crucial for successful discharge. Patients needed to identify at least 1 and ideally 2 caregivers to be available for assistance and to learn about device management. The training program was gradual, with daily sessions geared to the patient’s learning ability. In addition, caregivers met with a VAD nurse practitioner for at least 3 1-hour sessions. Before patients were eligible for discharge, they and their caregivers were required to demonstrate competency maintaining a logbook of VAD parameters, daily weights and vital signs, and with sterile wound care technique. They were also required to demonstrate a full knowledge in troubleshooting VAD alarms, and the ability to handpump the VAD and switch to a back-up portable driver.
Additional Support
The primary outcome of this study was the proportion of patients who were discharged home with a VAD. Additional outcomes included duration of VAD support, out-of-hospital time with the VAD, number of VAD complications, and hospital readmissions, with the exclusion of admissions for heart transplant, back-up call for a donor heart, device weaning, and desensitization. Event-free survival was defined as survival free of death, heart transplant, or device explant due to myocardial recovery.
A dedicated social worker played an active role in assisting patients and families in identifying support systems and adjusting to their illness. In addition, a VAD support group for patients living on mechanical circulatory support was initiated to foster emotional and social support and discuss strategies needed to manage living on a VAD. Community support and education were provided by the VAD nurse practitioners, who traveled to the patient’s communities and educated first responders, local physicians, emergency room staff, visiting nurses, and other family members and friends on device function and care. In particular, emergency troubleshooting for device problems was reviewed in detail, and a specific plan for local emergency response utilizing both air and ground transportation was arranged. After discharge, visiting nurses were responsible for wound care until the patient’s primary caregiver took over the responsibility. For 2 weeks after discharge, the caregiver was required to provide constant supervision. After this time, the amount of supervision was left to the discretion of the patient and family. Routine visits were scheduled and all patients were seen by a surgeon, cardiologist, and nurse practitioner 2 weeks after discharge, and then monthly in the outpatient VAD clinic. Nurse practitioners also maintained regular phone contact.
Medical Management
Statistical Analysis
All patients were treated with aspirin, dipyridamole, and warfarin dosed to a target international normalized ratio of 2.5 to 3.5. Diuretics and anti-hypertensive agents were used as needed to treat edema and hypertension, respectively. During this period we did not routinely institute comprehensive neurohormonal blockade with angiotensin-converting enzyme inhibitors, beta-blockers, and aldosterone antagonists unless there was potential for myocardial recovery. Once transferred out of the ICU, patients worked daily with physical and occupational therapy to build the necessary strength and endurance for home ambulation and independence with activities of daily living. Nutrition consultation was also a key
Statistical analyses were carried out using SAS version 9.2 (SAS Institute, Cary, NC). Descriptive statistics are reported as percentages, means standard error of the mean, and medians with interquartile range [25% to 75%]. The p values were calculated using the Wilcoxon rank-sum test for continuous variables and the c2 test for categorical values. In the instance where expected values in the contingency tables were below 5, p values were calculated using the Fisher exact test. Hazard ratios and Kaplan-Meier survival analyses were generated using MedCalc software version 12.2.1.0 (Mariakerke, Belgium). Censoring events included cardiac transplant or device explant for myocardial recovery.
Discharge Eligibility Patients were deemed discharge eligible upon successful transfer from the cardiac surgical intensive care unit (ICU) to the step-down unit after VAD implantation. Only those patients who were on a stable outpatient medical regimen, having successfully completed a comprehensive education program on VAD function and troubleshooting, and with appropriate social support, were discharged home [11].
Outcomes
ADULT CARDIAC
Ann Thorac Surg 2014;97:894–900
896 ADULT CARDIAC
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
Ann Thorac Surg 2014;97:894–900
Table 1. Baseline Characteristics of Patients With Paracorporeal Ventricular Assist Devices Characteristic Age, years Sex, n (%) Male Female Cardiomyopathy, n (%) Ischemic Non-ischemic LVEF INTERMACS profile, n (%) 1 2 3 or higher Positive inotropes, n (%) BUN, mg/dL Creatinine, mg/dL ALT, U/L, median [IQR] AST, U/L, median [IQR] Albumin, g/dL Hematocrit, % Platelet count, x1000/mL INR
LVAD (n ¼ 20)
BIVAD (n ¼ 26)
p Value
52 4
48 3
0.50
13 (65) 7 (35)
13 (50) 13 (50)
0.31
5 (25%) 15 (75%) 0.19 0.04
6 (23%) 20 (77%) 0.15 0.02
0.88
4 (20) 10 (50) 6 (30) 16 (80) 30 2 1.4 0.1 51 (20–108) 39 (29–401) 3.5 0.1 33 1 224 20 1.7 0.2
10 (38) 11 (42) 5 (19) 25 (96) 43 5 1.6 0.1 74 (19–274) 58 (25–129) 3.3 0.1 33 1 216 19 1.7 0.1
0.15
0.41
0.18 0.06 0.40 0.35 0.44 0.33 0.94 0.74 0.99
ALT ¼ alanine aminotransferase; AST ¼ aspartate aminotransferase; BIVAD ¼ biventricular assist device; BUN ¼ blood urea nitrogen; INR ¼ international normalized ratio; INTERMACS ¼ Interagency Registry for Mechanically Assisted Circulatory Support; IQR ¼ interquartile range; LVAD ¼ left ventricular assist device; LVEF ¼ left ventricular ejection fraction.
Results Patient Population Between February 2004 and September 2009, 47 patients with end-stage heart failure underwent implantation of a Thoratec paracorporeal VAD as a bridge to transplant. Of these, 20 patients received an LVAD, 26 required BIVADs, and 1 patient was excluded after having received an isolated right ventricular assist device. In the entire cohort, 57% of patients were male and 76% had a nonischemic cardiomyopathy. There were no significant differences in baseline characteristics between LVAD and BIVAD patients (Table 1), except for a trend toward higher blood urea nitrogen in the BIVAD group. Comorbidities included anemia, renal dysfunction, and poor nutrition. Most patients were in INTERMACS profile 1 (30%) or 2 (46%) at the time of VAD implantation.
ICU Transfer, Hospital Discharge, and Home Support Thirty patients (64%) were successfully transferred from the ICU to the step-down unit, and considered potential discharge candidates. Twenty-six (87%) of these patients were successfully discharged home (Table 2). The BIVAD patients tended to have a longer median hospital length of stay (BIVAD 54 days [37 to 74]; LVAD 33 days [27 to 38]; p ¼ 0.05). The overall home discharge rate for LVAD and BIVAD patients was not significantly different (58% and 55%, respectively; p ¼ 0.79). Four discharge eligible candidates (1 LVAD, 3 BIVAD) remained hospitalized for medical or psychosocial reasons. Of the 16 patients who were not candidates for discharge, 13 (28% of the total
cohort) died in the ICU. For discharged patients, the median support time did not differ between LVAD and BIVAD patients (61 days [37 to 107] and 66 days [24 to 119], respectively; p ¼ 0.84) with a maximum duration of home LVAD support of 517 days and BIVAD support of 221 days.
Readmissions After hospital discharge, there were 26 readmissions for medical or device-related complications, including 10 admissions in 7 LVAD patients and 16 admissions in 10 BIVAD patients. The complication event rates did not differ significantly between the 2 groups (Table 3). The median time to first readmission post discharge was 39 days [32 to 65] in patients with LVADs and 16 days [9 to 16] in those with BIVADs (p ¼ 0.29) (Table 2). The median length of stay for readmissions did not differ between the groups (LVAD, 3 days [0 to 17]; BIVAD, 9 days [0 to 45]; p ¼ 0.67). The most common reasons for readmission included device failure or alarms, driveline complications, and gastrointestinal and neurologic events (Table 3). The maximum number of readmissions experienced by any LVAD patient was 4 and 2 BIVAD patients had 3 readmissions each. Of the 17 patients with medical or device-related complications, 12 survived to transplant and 5 died.
Device-Related Readmissions Of the 26 readmissions for complications, 9 (35%) were device related. Device malfunction was the cause of readmission in 6 patients. Two patients (1 LVAD, 1
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
897
Table 2. Paracorporeal Ventricular Assist Device Outcomes Variable
LVAD
BIVAD
All patients: Implant admission, n (%) Discharge to home Discharge eligible in-hospital Discharge ineligible ICU death Survival Patients discharged home Outcome, n (%) Transplant Death Explant Implant to transplant/death/explant, days Implant to discharge, days Discharge to first readmission, days Device/medical readmissions per patient, n LOS for device/medical complication, days Out-of-hospital duration, days
n ¼ 20
n ¼ 26
11 (55) 1 (5) 2 (10) 6 (30) 11 (55) n ¼ 11
15 (58) 3 (11) 1 (4) 7 (27) 16 (62) n ¼ 15
8 3 0 91 33 39 1 3 61
(73) (27) (0) (81–152) (27–38) (32–65) (0–1) (0–17) (37–107)
12 2 1 158 54 16 1 9 66
p Value
0.79
0.61
(80) (13) (7) (131–199) (37–74) (9–67) (0–2) (0–45) (24–119)
0.78
0.09 0.05 0.29 0.56 0.67 0.84
Data reported as median with interquartile range unless otherwise stated. BIVAD ¼ biventricular assist device;
ICU ¼ intensive care unit;
BIVAD) experienced loss of sensor function and it was deemed unsafe to have them at home with their fill alarm silenced and operating in fixed mode. A third patient was at home on BIVAD support and lost the fill signal on the right VAD. Adequate LVAD decompression could not be maintained on the portable driver and the patient was maintained in the hospital on the dual drive console until transplant. An additional LVAD patient also experienced loss of the fill signal and remained in the hospital until transplant. Driveline complications occurred in 3 paracorporeal BIVAD patients. One patient was readmitted with an abdominal wound infection and required treatment with
LOS ¼ length of stay;
LVAD ¼ left ventricular assist device.
intravenous antibiotics. Two other patients were successfully managed at home with oral antibiotics.
Medical Complications Non-device related medical complications accounted for 17 readmissions. Of these, 6 (35%) were the result of neurologic events occurring in 4 patients. One LVAD patient accounted for 2 strokes and a seizure associated with a cardiac arrest. Two BIVAD patients suffered strokes and 1 LVAD patient presented with diplopia. Of this group, only 1 LVAD patient survived to transplant. Other medical reasons for readmission included symptomatic volume overload, ventricular arrhythmias,
Table 3. Paracorporeal Ventricular Assist Device Hospital Readmissions LVAD (n ¼ 11) Variable Patients with readmissions Overall readmissions Device-specific Malfunction/failure Driveline complication Medical-related Cardiac Infection Gastrointestinal Hematologic Neurologic BIVAD ¼ biventricular assist device;
n (%) 7 10 1 1 0 9 1 2 0 2 4
(63.6) (100) (10.0) (10.0) (0.0) (90.0) (10.0) (20.0) (0.0) (20.0) (40.0)
Events Per Patient Year 1.59 2.27 0.23 0.23 0.00 2.05 0.23 0.45 0.00 0.45 0.91
LVAD ¼ left ventricular assist device.
BIVAD (n ¼ 15) n (%) 10 16 8 5 3 8 0 2 2 2 2
(66.7) (100) (50.0) (13.3) (18.8) (50.0) (0.0) (12.5) (12.5) (12.5) (12.5)
Events Per Patient Year
p Value
1.45 2.32 1.16 0.73 0.44 1.16 0.00 0.16 0.29 0.29 0.29
0.85 0.96 0.09 0.26 0.17 0.24 0.21 0.65 0.26 0.65 0.17
ADULT CARDIAC
Ann Thorac Surg 2014;97:894–900
898 ADULT CARDIAC
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
Ann Thorac Surg 2014;97:894–900
bacterial and viral infection, acute cholecystitis, and druginduced hemolytic anemia (in 2 BIVAD patients).
Overall Outcomes By Kaplan Meier analysis, event-free survival was not significantly different between LVAD and BIVAD patients at 30 days, 6 months, and 1 year after device implantation (p ¼ 0.52) (Fig 1). Of the 26 device patients discharged home, 20 (77%) were successfully transplanted, 5 (19%) died, and 1 underwent VAD weaning and device explant (Table 2). Among patients either eligible for discharge or discharged home, there was also no significant difference in event-free survival between LVAD and BIVAD patients at 30 days, 6 months, or 1 year after device implantation (p ¼ 0.35), (Fig 2).
Comment In this single-center study, we describe our experience with paracorporeal VADs and demonstrate that patients with BIVADs have similar post discharge outcomes as those with left ventricular support only. With comparable numbers and types of readmissions, and similar survival at 6 months and 1 year, our data support the recommendation that both LVAD and BIVAD patients can live at home safely on a portable driver while awaiting heart transplant. After discharge, we observed no difference in the rates or types of hospital readmissions experienced by either VAD type. The most common reasons for readmission were stroke, device malfunction, and infection. As demonstrated in prior experiences with the Thoratec paracorporeal VAD and other pulsatile LVADs [12–14], thromboembolic events contributed to significant morbidity and mortality, including 3 deaths. All patients were maintained on combination antiplatelet and
Fig 1. Event-free survival after device implantation. There were no differences in Kaplan-Meier survival estimates between LVAD or BIVAD patients at 30 days (LVAD 78.9 [0.09], BIVAD 72.7 [0.09]); 6 months (LVAD 58.3 [0.13], BIVAD 60.0 [0.11]); or 1 year (LVAD 19.4 [0.16], BIVAD 51.4 [12]) (p ¼ 0.52). Hazard ratio 0.75; 95% CI 0.30 to 1.88. (BIVAD ¼ biventricular assist device; CI ¼ confidence interval; LVAD ¼ left ventricular assist device.)
Fig 2. Paracorporeal device survival contingent on discharge eligibility. There were no differences in Kaplan-Meier survival estimates between LVAD or BIVAD patients at 30 days (LVAD 91.7 [0.08], BIVAD 100 [0.0]; 6 months (LVAD 78.6 [0.14], BIVAD 82.5 [0.12]; or at 1 year (LVAD 39.3 [0.29]; BIVAD 71.7 [0.15]) after device implantation (p ¼ 0.35). Hazard ratio 0.50; 95% CI 0.09 to 2.73. (BIVAD ¼ biventricular assist device; CI ¼ confidence interval; LVAD ¼ left ventricular assist device.)
anticoagulation therapy, and international normalized ratios were therapeutic at the time of the events. While underlying infection may predispose to cerebrovascular events in VAD patients [15, 16], we observed active infection in only 1 patient at the time of stroke. Duration of out-of-hospital VAD support averaged 61 days for LVAD patients and 66 days for BIVAD patients, which is comparable with previously published experiences [17, 18]. Device failure was not found to be a serious complication in patients discharged home on the portable driver, although it did necessitate readmission and alteration in device settings. Notably, all patients with device malfunction went on to successful cardiac transplant, indicating that device failure did not significantly increase morbidity. However, inpatient monitoring was felt to be necessary for patient safety. Although VAD mechanical dysfunction was not life threatening in our patients, quality control issues associated with the portable driver proved to be a negative aspect of the “bridge” experience. With medium- to long-term outpatient use, components of the system, including cables, batteries, and the drivers themselves, needed to be replaced. During the observation period, there was a US Food and Drug Administration recall in which certain drivers needed to be returned to the manufacturer. In several instances we erred on the side of safety and kept patients hospitalized until transplant. Patients requiring biventricular support are typically critically ill at the time of implantation (eg, INTERMACS profile 1 and 2). In our cohort, we did not observe significant baseline differences in LVAD and BIVAD patients, but this may reflect small patient numbers as there were trends toward greater inotrope use, higher blood urea nitrogen, and lower average INTERMACS
profiles in the BIVAD group. Event-free survival was similar in LVAD and BIVAD patients, with rates comparable with previous studies [17, 18]. A recent INTERMACS analysis found that BIVAD patients were more critically ill with greater morbidity and mortality than LVAD patients [19]. These data may differ from ours due to the larger sample size and greater acuity of the BIVAD population in INTERMACS. In contrast, indices of end-organ function were similar and reasonably preserved in our patients with either BIVAD or LVAD support. Among published studies, the number of patients implanted and discharged home with BIVADs is few [17, 18]. The 15 BIVAD patients discharged from our institution represent a relatively large single-center experience. While paracorporeal VADs had previously been the predominant mechanical circulatory support strategy for patients awaiting cardiac transplant [20], recent data [8] show that these numbers have significantly diminished due to limitations in durability, complications including infection, and barriers to discharge. This has led to the emergence of alternative types of biventricular support, including the TAH. However, paracorporeal VADs remain the preferred strategy when TAH candidacy is constrained by small body size, or lack of institutional experience or availability. Recently, the Reflection Group on Mechanical Circulatory Support reported similar overall patient survival with TAH and implantable or paracorporeal BIVADs [21]. However, when device support extended beyond 90 days, survival was greater with TAH, with a lower incidence of neurologic events. While we could not compare home paracorporeal BIVAD outcomes with TAH patients, future data from the SynCardia TAH freedom driver study (clinicaltrials.gov, NCT00733447) should help to inform these comparisons. More recently, the use of a bilateral continuous flow pump system consisting of HeartWare HVADs (Framingham, MA) has emerged as another potential option for patients requiring biventricular support. The smaller size (162 g) and intrapericardial implantation of the HVAD pump facilitates use in patients who would otherwise be ineligible for a total artificial heart. A recent report observed an 82% 30-day survival rate, with more than 50% of patients discharged home [22]. At our institution, discharge eligibility is dependent upon the establishment of specific patient, caregiver, and support network contingencies that ensure the greatest likelihood for outcome success. Competence in device maintenance, including driveline care and device alarm recognition and interpretation, are prerequisites for discharge. In addition to close clinic and telephone follow-up, our multidisciplinary VAD team also extends to a community-based network of providers, including first responders, local primary care physicians, and emergency room clinicians who may be involved in patient care. While there can be strong institutional motivations to discharge VAD patients, the anticipated psychologic, social, and emotional adjustments for patients and their caregivers cannot be underestimated, and may be further
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
899
amplified by the need for biventricular support. We based our study and its conclusions on the assumption that patients prefer to be at home while awaiting transplant [23]. However, some patients felt extremely anxious about being discharged, and this was a frequent focus of discussion in the VAD support group. Factors such as reduced proximity to knowledgeable health care professionals and fear of device malfunction added significantly to predischarge anxiety. Additional stressors included adjustments to activities of daily living, living space modifications, and maintenance of social and sexual relations [24]. A few limitations are inherent in our study. First, the retrospective design and small sample size make it difficult to draw strong conclusions. Further prospective studies with larger numbers of patients from multiple centers are needed. Beyond assessing survival, additional analyses are necessary to compare quality of life before and after discharge. The choice of a paracorporeal LVAD versus BIVAD was a clinical decision made in patients with significant hemodynamic compromise. While risk scores for right heart failure were considered [25], they did not dictate device choice. In summary, we demonstrated the safety and efficacy of home paracorporeal biventricular assist in patients with end-stage heart disease. While significant risks with this strategy exist, outcomes were not different compared with patients bridging to transplant on paracorporeal LVADs. With comprehensive patient and caregiver education, discharge for medically stable patients demonstrating device competency and adequate home support is feasible and should be offered regardless of the need for paracorporeal univentricular or biventricular support.
References 1. Rose EA, Gelijns AC, Moskowitz AJ, et al. Long-term mechanical left ventricular assistance for end-stage heart failure. N Engl J Med 2001;345:1435–43. 2. Slaughter MS, Rogers JG, Milano CA, et al. Advanced heart failure treated with continuous-flow left ventricular assist device. N Engl J Med 2009;361:2241–51. 3. Karamlou T, Gelow J, Diggs BS, et al. Mechanical circulatory support pathways that maximize post-heart transplant survival. Ann Thorac Surg 2013;95:480–5. 4. Kirklin JK, Naftel DC, Kormos RL, et al. The Fourth INTERMACS Annual Report: 4,000 implants and counting. J Heart Lung Transplant 2012;31:117–26. 5. Copeland JG, Smith RG, Arabia FA, et al. Cardiac replacement with a total artificial heart as a bridge to transplantation. N Engl J Med 2004;351:859–67. 6. Copeland JG, Copeland H, Gustafson M, et al. Experience with more than 100 total artificial heart implants. J Thorac Cardiovasc Surg 2012;143:727–34. 7. Farrar DJ, Buck KE, Coulter JH, Kupa EJ. Portable pneumatic biventricular driver for the Thoratec ventricular assist device. ASAIO J 1997;43:M631–4. 8. Kirklin JK, Naftel DC, Kormos RL, et al. Fifth INTERMACS annual report: risk factor analysis from more than 6,000 mechanical circulatory support patients. J Heart Lung Transplant 2013;32:141–56. 9. Givertz MM. Heart allocation in the United States: intended and unintended consequences. Circ Heart Fail 2012;5:140–3.
ADULT CARDIAC
Ann Thorac Surg 2014;97:894–900
900 ADULT CARDIAC
THOMAS ET AL HOME BIVAD AS BRIDGE TO TRANSPLANT
10. Stevenson LW, Pagani FD, Young JB, et al. INTERMACS profiles of advanced heart failure: the current picture. J Heart Lung Transplant 2009;28:535–41. 11. Wilson SR, Givertz MM, Stewart GC, Mudge GH Jr. Ventricular assist devices: the challenges of outpatient management. J Am Coll Cardiol 2009;54:1647–59. 12. Farrar DJ. The Thoratec ventricular assist device: a paracorporeal pump for treating acute and chronic heart failure. Semin Thorac Cardiovasc Surg 2000;12:243–50. 13. Kirsch M, Vermes E, Damy T, et al. Single-centre experience with the Thoratec paracorporeal ventricular assist device for patients with primary cardiac failure. Arch Cardiovasc Dis 2009;102:509–18. 14. Brehm K, Heilmann C, Siepe M, Benk C, Beyersdorf F, Schlensak C. Thoratec paracorporeal biventricular assist device therapy: the Freiburg experience. Eur J Cardiothorac Surg 2012;41:207–12. 15. Tsukui H, Abla A, Teuteberg JJ, et al. Cerebrovascular accidents in patients with a ventricular assist device. J Thorac Cardiovasc Surg 2007;134:114–23. 16. Aggarwal A, Gupta A, Kumar S, et al. Are blood stream infections associated with an increased risk of hemorrhagic stroke in patients with a left ventricular assist device? ASAIO J 2012;58:509–13. 17. Slaughter MS, Sobieski MA, Martin M, Dia M, Silver MA. Home discharge experience with the Thoratec TLC-II portable driver. ASAIO J 2007;53:132–5.
Ann Thorac Surg 2014;97:894–900
18. Oosterom A, de Jonge N, Kirkels JH, et al. End-stage heart failure and mechanical circulatory support: feasibility of discharge from hospital. Neth Heart J 2007;15:45–50. 19. Cleveland JC Jr, Naftel DC, Reece TB, et al. Survival after biventricular assist device implantation: an analysis of the Interagency Registry for Mechanically Assisted Circulatory Support database. J Heart Lung Transplant 2011;30:862–9. 20. Berman M, Parameshwar J, Jenkins DP, et al. Thoratec implantable ventricular assist device: the Papworth experience. J Thorac Cardiovasc Surg 2010;139:466–73. 21. Kirsch M, Mazzucotelli JP, Roussel JC, et al. Survival after biventricular mechanical circulatory support: does the type of device matter? J Heart Lung Transplant 2012;31:501–8. 22. Krabatsch T, Potapov E, Stepanenko A, et al. Biventricular circulatory support with two miniaturized implantable assist devices. Circulation 2011;124(11 Suppl):S179–86. 23. Marcuccilli L, Casida JJ, Peters RM, Wright S. Sex and intimacy among patients with implantable left-ventricular assist devices. J Cardiovasc Nurs 2011;26:504–11. 24. Grady KL, Meyer PM, Dressler D, et al. Longitudinal change in quality of life and impact on survival after left ventricular assist device implantation. Ann Thorac Surg 2004;77:1321–7. 25. Matthews JC, Koelling TM, Pagani FD, Aaronson KD. The right ventricular failure risk score: a pre-operative tool for assessing the risk of right ventricular failure in left ventricular assist device candidates. J Am Coll Cardiol 2008;51: 2163–72.
INVITED COMMENTARY Congratulations to the authors [1]. It is refreshing to find an article in the field of mechanical circulatory support that is scientifically sound and honestly presents a contemporary experience that challenges the current wave of enthusiasm for supporting everyone with continuous-flow left ventricular assist devices (LVADs). This experience is exclusively with pulsatile paracorporeal devices, LVADs and biventricular assist devices (BIVADs). The BIVADs are assist, not replacement, devices. The authors selected BIVAD support preemptively in over half of their patient population and did equally well with the BIVAD group as with the LVADs, even though there was a consistent trend for BIVAD patients to be sicker before implantation (blood urea nitrogen levels higher, INTERMACS [Interagency Registry for Mechanically Assisted Circulatory Support] status sicker, more use of inotropic agents, ejection fraction lower). The patient population was fairly homogeneous, with 80% having INTERMACS status 1 or 2, 75% having nonischemic heart failure, and all being candidates for transplantation. Device selection was surgical: “Left ventricular versus biventricular support was a surgical decision determined by hemodynamics, echocardiography, and end-organ function.” The risk scores for right ventricular failure did not dictate the choice of device. I have to agree that this should be a surgical decision and that risk scores should never dictate a final clinical decision. In this study there were 20 LVADs and 26 BIVADs. Right ventricular failure was recognized and addressed by BIVAD implantation. The authors offer hope for patients in right heart failure who need a BIVAD, and they offer knowhow for those seeking to discharge these arguably more complicated patients. Survival results
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
“overall” and “contingent upon discharge eligibility” were similar for the LVAD and BIVAD groups. The home discharge rate of nearly 60%, the readmission rates, and the adverse event rates were all comparable. This, for the BIVAD group, is amazing. I am unaware of any other report of outpatient BIVAD, external or implantable, pulsatile or nonpulsatile, that presents equal results. A large part of the success of outpatient BIVAD support in this study no doubt resulted from education of the patient and family, good communication, and excellent medical and psychological care. Thus, the authors and their team in a highly credible institution have documented the need for and usefulness of BIVADs and the possibility of hospital discharge of patients with BIVADs. Dr Copeland discloses a financial relationship with SynCardia Systems, Inc. Jack Copeland, MD Department of Surgery UC San Diego 9444 Medical Center Dr 3-020 ECOB 3rd Flr La Jolla, CA 85724-507 192037 e-mail: [email protected]
Reference 1. Thomas SS, Smallwood J, Smith CM, et al. Discharge outcomes in patients with paracorporeal biventricular assist devices. Ann Thorac Surg 2014;97:894–900.
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2013.10.020