Safety and Effectiveness of the Medtronic Resting Heart Bypass System in Heart Surgery Patients
Condition: Coronary Artery Bypass Surgery; Cardiopulmonary Bypass
Study type: Interventional
Phase: Phase 1

Summary: 
      The purpose of this study is to determine if the Medtronic Resting Heart Bypass system is
      safer and results in less inflammatory reaction than traditional bypass machines used in
      coronary artery bypass surgery. We hypothesize that the new Medtronic Resting Heart System is
      safer and results in much less systemic inflammatory reaction in comparison to the standard
      cardiopulmonary bypass systems currently in use.
    

Detailed description: 
      Cardiopulmonary bypass (CPB) has played an extremely crucial role in coronary artery bypass
      grafting (CABG) surgery for the past five decades. During CABG, the CPB machine enables the
      surgeon to stop the heart and perform the surgery in a bloodless operating field. The CPB
      machine essentially takes over the job of the heart by oxygenating the blood and then
      perfusing the entire body. In patients undergoing CABG surgery with CPB, a systemic
      inflammatory reaction occurs when the blood is taken out of the body and circulated through
      the CPB machine. This inflammatory reaction is believed to increase postoperative morbidity
      and prolong hospital stay. The systemic inflammatory reaction results in activation of the
      complement, coagulation, fibrinolytic and kallikrein cascades, it activates leukocytes and
      endothelial cells causing expression of adhesion molecules and results in the release of
      inflammatory mediators such as cytokines. This inflammatory reaction during CPB leads to
      vasodilation, increased interstitial fluid and can affect organs such as the heart, lungs,
      brain and kidneys resulting in their dysfunction(s). Elimination of CPB in patients
      undergoing CABG surgery has resulted in reduction of this inflammatory response.
      Unfortunately, not all patients are able to undergo CABG without the use of CPB.

      Most conventional CPB systems also use cardiotomy suction which returns all the blood
      collected in the operative field back to the CPB reservoir and then eventually returns it to
      the patient. This blood is rich in inflammatory mediators and small particles because it has
      been activated by surgical trauma and by the proteins lining the wound cavity. Returning this
      blood back into the CPB circuit results in further circulation of inflammatory mediators.
      Removal of the cardiotomy suction from the CPB system could potentially decrease the
      inflammatory mediators and reduce the inflammatory response during CPB.

      Recently, there have been attempts to decrease the inflammatory reaction caused by the use of
      CPB by developing better, more effective systems. The Medtronic Resting Heart System is very
      similar to conventional CPB systems and has been approved for clinical use both in Canada and
      the United States. It has some potential advantages over traditional bypass machines which
      include; 1)a fully closed-to-air system that does not allow an air-blood interface which
      could prevent blood activation, 2)it does not have cardiotomy suction and therefore prevents
      air, lipids or particulate emboli from being re-introduced into the patient's circulation,
      3)it minimizes hemodilution by using smaller and low-prime circuits, possibly decreasing the
      need for postoperative blood transfusion, 4)the CPB circuit, which is the blood-contacting
      surface, is coated with Carmeda Bioactive Surface (a heparin bioactive surface), that mimics
      critical characteristics of vascular endothelium and may prevent further blood activation,
      and 5)it has an active venous air detector and removal device (VARD) that detects venous air
      and automatically removes the air which may prevent blood activation. All of these elements
      are potential benefits which may further reduce the morbidity and inflammation associated
      with CABG surgery.

      Thus far to our knowledge, there have been no studies looking at the inflammatory reaction
      and morbidity in patients undergoing CABG procedures using more improved cardiopulmonary
      bypass machines. We are therefore proposing a prospective, randomized trial of the safety and
      effectiveness of the Medtronic Resting Heart system in CABG surgery.
    

Intervention name(s): Medtronic Resting Heart Bypass System
Intervention type(s): Device
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single
Primary purpose: Treatment
Keywords: Cardiopulmonary bypass; Inflammatory reaction