The Epidemiology of Bleeding and Clotting in Patients Undergoing Heart Transplantation, Coronary Artery Bypass Graft Surgery,or Implantation of Left Ventricular Assist Devices

The Epidemiology of Bleeding and Clotting in Patients Undergoing Heart Transplantation, Coronary Artery Bypass Graft Surgery,or Implantation of Left Ventricular Assist Devices

The purpose of this study is to obtain data or information on how blood clotting factors are activated during open heart surgery. In particular, the investigators are interested in how blood clotting factors are activated by the heart-lung bypass machine and by left ventricular assist devices (LVAD). Patients on these two machines have an increased risk of bleeding and blood clot formation. This is because both machines stimulate the intrinsic coagulation pathway, one of the chemical pathways that cause blood to clot. The process of surgery itself also stimulates the "extrinsic coagulation pathway," the other chemical pathway that causes blood to clot. Stimulating these coagulation pathways can use up the body's clotting factors. As a result, patients may be at risk for both bleeding and blood clot formation. The investigators would like to study how the blood factors are activated during and after surgery, to help develop treatments to prevent bleeding and clot formation.

This is a prospective, multi-center, observational study to characterize the epidemiology of bleeding and clotting in patients with underlying systolic ventricular dysfunction undergoing heart transplantation, CABG surgery, or implantation of left ventricular assist devices. Patients will be followed for up to 28 days post-implant, post-CABG, post-heart transplant, or until hospital discharge, whichever comes first. There will be no randomization for this observational study.

We will enroll 100 patients (we expect the distribution to be approximately 30 per Groups I - III, but no cap per group, and 10 for Group IV) who have been scheduled to undergo CPB within 24 hours for one of the following:

Group I: Cardiopulmonary Bypass + Heart Transplantation CPB for orthotopic heart transplantation (excluding any patients with VADs)

Group II: Cardiopulmonary Bypass + Pulsatile LVAD CPB for implantation of a Thoratec HeartMate® I LVAD (for destination therapy or bridge to transplantation)

Group III: Cardiopulmonary Bypass + Continuous Flow LVAD CPB for implantation of an axial flow or centrifugal flow LVAD (for destination therapy or bridge to transplantation) (e.g. HeartMate® II, DeBakey VAD® or VentrAssist® LVAS)

Group IV: Cardiopulmonary Bypass + CABG/Valve Surgery CPB for CABG or valve surgery

Heart transplantation and perioperative care will be performed in accordance with the standard of care at the clinical center. Pulsatile LVAD (e.g. HeartMate® I) implantation and perioperative management will be performed in accordance with the standard of care at the clinical center, and guided by the HeartMate® I Directions for Use. Continuous flow LVAD implantation and perioperative management will be performed in accordance with the standard of care at the clinical center, and guided by the specific VAD manufacturer's Directions for Use. CABG surgery and perioperative care will be performed in accordance with the standard of care at the clinical center.

We anticipate that enrollment will be completed over a six-month period.

We hypothesize that the initial activation of the intrinsic pathway of coagulation is attenuated for several days in patients undergoing CPB for CABG alone; however, in subjects undergoing CPB with VAD implantation or cardiac transplantation, activation of this pathway is biphasic and sustained.

Inclusion Criteria:

1. Signed informed consent, release of medical information, and HIPAA forms;

2. Age greater than or equal to 18 years;

3. Male, postmenopausal female, or female who may become pregnant but is using adequate contraceptive precautions (defined as oral contraceptive, intrauterine devices, surgical contraception or a combination of a condom and a spermicide), with negative pregnancy test;

4. Admitted to the clinical center at the time of enrollment;

5. Approved and scheduled to undergo one of the following within 24 hours of enrollment:

   • Orthotopic heart transplantation
   • CABG and/or valve surgery on CPB; these patients must have an LV ejection fraction of ≤35%
   • Implantation of a pulsatile LVAD (e.g.Thoratec HeartMate® I LVAD) for destination therapy or bridge to transplantation
   • Implantation of a continuous flow LVAD (e.g. HeartMate® II, DeBakey VAD® or VentrAssist® LVAS) for destination therapy or bridge to transplantation

Exclusion Criteria:

1. History of a platelet disorder;
2. History of a known, or an inherited, or an acquired coagulation disorder in the study subject;
3. Stroke within 30 days prior to enrollment;
4. Allergy to heparin or protamine;
5. Participation in a clinical investigational intervention trial, with the exception of an investigational VAD trial, at the time of enrollment;
6. Received investigational intervention within 30 days of enrollment, with the exception of an investigational VAD trial