All patients studied met the clinical trial enrollment criteria and the general criteria for BTT/DT LVAD implantation as published by the Centers for Medicare and Medicaid Services (CMS) [23], including chronic end-stage heart failure (New York Heart Association [NYHA] class IV symptoms failing to respond to optimal medical management, end-stage left ventricular failure for at least 90 days, and a life expectancy of less than 2 years); left ventricular ejection fraction (LVEF) <25 %; demonstrated functional limitation with peak VO₂ < 12 mL/kg/min; or continued need for intravenous (I.V.) inotropic therapy ; and an appropriate body size to support LVAD implantation [23].

Through a National Coverage Determination issued on October 2003, Medicare began coverage of the DT indication, and effective March 27, 2007, new facility criteria were established which require hospitals to receive certification from the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) [23]. Facilities gaining JCAHO certification are placed on a list on the CMS website, which is continuously updated [23, 24]. During the current study, our facility achieved and maintained JCAHO certification as a Medicare-approved VAD facility.

The criteria adopted for selecting LVAD candidates are summarized in Table 3.2. All patients underwent comprehensive evaluation and treatment prior to LVAD placement, which included clinical assessment of the severity of heart failure , hemodynamic state , cardiac anatomy, and operative risk. Inotropic support, diuresis or ultrafiltration, infection surveillance/treatment, and nutritional assistance were provided when needed. Based on the response to treatment, it was determined if the patient should continue on medical treatment or hospice and offered high-risk surgical repair with LVAD standby or become a candidate for destination LVAD therapy or transplantation . For nonresponders the decision was whether they were appropriate LVAD candidates or too sick for support. Noncardiac considerations such as history of chronic or life-limiting illnesses, mental status, nutritional status, expectations (quality of life vs. duration of life), and psychosocial and age-related considerations were assessed.

In our initial study [30], 55 consecutive patients receiving HMII LVADs included in the BTT or DT clinical trials from October 2005 through January 2010 at a small community hospital with extensive MCS experience were evaluated. Patients were divided into two groups based on age at the time of implant: Group 1, patients under the age of 70 (n = 25) and Group 2, patients 70 years or older (n = 30). During the study period, 329 patients were referred for consideration of LVAD or transplantation of which 15 % (49/280) were 70 years or older. The majority of patients, 61 % (30/49), 70 years of age or older, accepted and underwent HMII implant. Four patients (8 %) were considered to be good candidates but refused our recommendation; 16 % (8/49) were too well while only 8 % (4/49) were too ill. In the younger than 70 population 46 % (103/280) either received a HMII or were transplanted, 14 % (40/280) were too well, 5 % (13/280) underwent a traditional cardiac operation, 4 % (10/280) were too ill, 13 % (37/280) were not considered to be good LVAD candidates, 8 % (24/280) failed to keep their appointment, and 3 % (9/280) refused to accept our advice for LVAD or transplant. Only patients implanted as part of the HMII trial were studied since complete datasets were available only for these patients.

The two groups were compared with regard to preoperative patient characteristics and outcome measures including Kaplan–Meier survival , prevalence and incidence of adverse events , quality of life metrics (Kansas City Cardiomyopathy Questionnaire [KCCQ], clinical summary score [CSS], and overall summary scores [OSS], Minnesota Living With Heart Failure Questionnaire [MLWHF]), and functional status six-minute walk distance [6MWD], New York Heart Association (NYHA) function class, and patient activity levels with Metabolic Equivalent Task Score (METS) [21].

Statistical analyses except for Poisson regression were done using Systat (Cranes Software, Chicago, IL). Poisson regression was performed using SAS (SAS Institute Inc., Cary, NC). Differences between groups of independent, normally distributed, continuous variables were evaluated using the t-test. Variables that were not normally distributed were evaluated using the Mann–Whitney U-test. Normality was checked using the Anderson–Darling test . Differences in categorical variables were evaluated using the Fisher’s exact test . Statistical comparisons were two-sided and the level of significance was set at p < 0.05. Survival analysis was performed using the Kaplan–Meier method with patients censored for transplantation , recovery of the native heart function with device removal, or withdrawal from the study. Comparison of survival between the two groups was performed using the log-rank test. Adverse events were presented as both percentages of patients and event rates (events per patient-year). Comparisons of adverse event rates between the two groups were performed using a Poisson regression model (Mantel–Haenszel), with the total duration of support as the exposure time and total number of events as the response variable. Quality of life comparisons were performed using linear mixed effects modeling (mixed subroutine in Systat). The predictor variables were age group and time group (baseline, 1, 3, and 6 months). Time group: Eight patients (four in each group) had a previous pulsatile flow LVAD which was replaced with a HMII LVAD. Duration of support and survival for these patients was evaluated from the date of the first LVAD implant. Only adverse events that were observed when on the HMII device were included.