The primary endpoint of the trial is stroke-free survival at two years, defined as alive on the originally implanted device, electively transplanted or explanted due to patient recovery and free from disabling stroke (Modified Rankin Scale >=4). The Modified Rankin Scale is scored from 0 to 6, where 0 indicates an absence of symptoms and 6 indicates death. A score of 4 or higher indicates moderately severe or greater disability. Weibull model estimates of survival probability (shown as a percent of 100) are used.

Only randomized subjects who successfully received an implant are included.

Number of participants with bleeding, per Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) definition. The event of bleeding is defined as: An episode of suspected internal or external bleeding that results in one or more of the following:

1. Death,
2. Re-operation,
3. Hospitalization,
4. Transfusion of red blood cells as follows:

During first 7 days post implant

• Adults (≥ 50 kg): ≥ 4U packed red blood cells (PRBC) within any 24 hour period during first 7 days post implant.

After 7 days post implant

• Any transfusion of packed red blood cells (PRBC) after 7 days following implant.

Only randomized subjects who successfully received an implant are included.

Number of participants with major infections, per INTERMACS definition. A major infection is defined as: A clinical infection accompanied by pain, fever, drainage and/or leukocytosis that is treated by anti-microbial agents (non-prophylactic). A positive culture from the infected site or organ should be present unless strong clinical evidence indicates the need for treatment despite negative cultures. The general categories of infection include Localized non-device infection Percutaneous site and/or pocket infection Internal pump component, inflow or outflow tract infection Sepsis

Only randomized subjects who successfully received an implant are included.

Overall survival is the probability (expressed as a percent of 100) did not died within 2 years post implant via the Kaplan-Meier method. Participants that did not died were censored at the time of last follow-up or 2 years post implant, whichever occurred first.

Only randomized subjects who successfully received an implant are included.

Number of Participants with device malfunctions per INTERMACS definition. Device malfunction denotes a failure of one or more of the components of the Mechanical Circulatory Support Device (MCSD) system which either directly causes or could potentially induce a state of inadequate circulatory support (low cardiac output state) or death. The manufacturer must confirm device failure. A failure that was iatrogenic or recipient-induced will be classified as an Iatrogenic/Recipient-Induced Failure.

Device failure should be classified according to which components fails as follows:

1. Pump failure (blood contacting components of pump and any motor or other pump actuating mechanism that is housed with the blood contacting components).
2. Non-pump failure (e.g., external pneumatic drive unit, electric power supply unit, batteries, controller, interconnect cable, compliance chamber)

Only randomized subjects who successfully received an implant are included.

Health Status change as measured by Kansas City Cardiomyopathy Questionnaire (KCCQ) Overall Summary Score. The KCCQ is a disease-specific patient-reported outcomes measure for patients with heart failure. It consists of 23 items, is comprised of 7 clinically relevant scales (Symptom Frequency, Symptom Burden, Symptom Stability, Physical Limitation, Social Limitation, Quality of Life, and Self-Efficacy), and yields 3 summary scores (Clinical Summary, Total Symptom, and Overall Summary Scores). Scale and summary scores range between 0 and 100, with higher scores indicating better health status (e.g., better functioning, fewer symptoms, better quality of life). The Overall Summary Score is calculated as the mean of the Physical Limitation, Total Symptom, Quality of Life and Social Limitation scores. A positive change in score from baseline indicates an improvement.

Only randomized subjects who successfully received an implant are included. Subjects also had to reach the Month 24 visit and complete both the baseline and Month 24 assessments to be analyzed.

The EuroQol-5D (version 3L) is a brief self-administered, validated instrument consisting of 2 parts. The second part consists of the EQ-5D general health status as measured by a visual analog scale (EQ-5D VAS). EQ-5D VAS measures the participant's self-rated health status on a scale from 0 (worst imaginable health state) to 100 (best imaginable health state). An adjustment was done on the response where the scores were normalized based on this paper: Johnson JA, Coons SJ. Comparison of the EQ-5D and SF-12 in an adult US sample. Qual Life Res. 1998 Feb;7(2):155-66.

Only randomized subjects who successfully received an implant are included. Subjects also had to reach the Month 24 visit and complete both the baseline and Month 24 assessments to be analyzed.

Change in Functional status, as measured by New York Heart Association (NYHA) class. There are 4 levels of NYHA:

I (Mild): No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, or dyspnea.

II (Mild): Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, palpitation, or dyspnea.

III (Moderate): Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes fatigue, palpitation, or dyspnea.

IV (Severe): Unable to carry out any physical activity without discomfort. Symptoms of cardiac insufficiency at rest. If any physical activity is undertaken, discomfort is increased. Improvement is defined as moving from a higher numerical NYHA level to a lower numerical NYHA level (e.g., IV to III).

Only randomized subjects who successfully received an implant are included. Subjects also had to reach the Month 24 visit and complete both the baseline and Month 24 assessments to be analyzed.

Change in functional status, as measured by 6-minute walk test.

Only randomized subjects who successfully received an implant are included. Subjects also had to reach the Month 24 visit and complete the assessment or indicate Not Completed to be analyzed at both the baseline and Month 24 visits. If the subject did not complete the assessment, a value of 0 was imputed.

Length of Initial Hospitalization post implant

Only randomized subjects who successfully received an implant are included. Subjects are analyzed based on the device they actually received. Subjects who died while in the hospital or have a missing discharge date were not included.

Number of participants who had a re-hospitalization while on the device

Only randomized subjects who successfully received an implant are included. Subjects are analyzed based on the device they actually received.

Duration of Re-hospitalization while on device

Only randomized subjects who successfully received an implant are included. Subjects are analyzed based on the device they actually received. Subjects who died while in the hospital or have a missing discharge date were not included.

Cause of Re-hospitalization while on device. The reason a participant may have been re-hospitalized was due to an adverse event, the need for an explant, or for various "Other" reasons.

Only randomized subjects who successfully received an implant are included. Subjects are analyzed based on the device they actually received.