Current Studies

1. Blood Pumps

Continuous-Flow Total Artificial Heart

This study pertains to the development of an innovative, sensorless, pulsatile, continuous-flow total artificial heart (CFTAH) to support patients with biventricular failure. This CFTAH consists of a one-piece moving rotor with impeller blades on each end driving right and left chamber mounted centrifugal continuous flow pumps. This device can be made much smaller than pulsatile TAHs with no prosthetic valves or diaphragmatic pumping chambers. It can overcome the size, reliability and thromboembolic complications that have prevented the previous pulsatile TAHs from being used in clinical practice. In the recent 3 consecutive, chronic animal experiments (one 30-day and two 90-day experiments) performed without anticoagulation therapy, good biocompatibility was demonstrated.

New Left and Right Ventricular Assist Devices by Perfusion Solutions Inc. (PSI)

We are collaborating with PSI to evaluate their new LVAD and RVAD that are in development under NIH SBIR programs. Chronic experiments in calves are underway.

 

2. Devices and Procedures

Cardioscope Intracardiac Visualization and Surgery in a Beating Heart

Cardioscopy is a novel imaging method that isolates the operative ventricle from the rest of the blood circulation during cardiopulmonary bypass. It uses a second clear fluid imaging bypass circuit to fill the operative ventricle while the heart is beating. This allows for the deployment of an endoscopic camera and surgical tools via minimally invasive surgical access and produces closed-chest real time fiberoptic imaging of intracardiac structures. Collaborating with Cleveland Clinic cardiac surgeon Dr. Tomislav Mihaljevic, the CDL has demonstrated the technical feasibility of mitral and tricuspid valve repairs under direct visualization in the beating heart in an open chest animal model. We continue to develop this method in an animal model for use in intracardiac surgery in a closed chest procedure. The successful completion of this research will provide clinicians with a less invasive surgical tool, allowing performance of a wide spectrum of closed-chest cardiac operations under direct visualization.

Left Atrial Exclusion Device for Prevention of Stroke in Atrial Fibrillation Patients

Atrial fibrillation (AF) is a common cardiac arrhythmia that affects more than 2 million people annually. One of its more serious complications is the formation of clotted blood (thrombus) in the left atrial appendage (LAA) due to blood stagnation. This can lead to release of the thrombus into the blood stream (embolism) causing the blockage of blood flow within downstream major organs (stroke). If the LAA is isolated from the left atrial circulation, potential strokes can be avoided.

Collaborating with Cleveland Clinic cardiac surgeon Dr. A. Marc Gillinov, and our sponsor, AtriCure, Inc., the CDL has evaluated a novel left atrial clip to isolate the LAA in preclinical animal studies. The AtriClip™ Gillinov-Cosgrove LAA Exclusion System is a clip composed of two curved parallel and rigid titanium tubes and two nitinol springs with p olyester fabric. The AtriClip is easily and quickly applied to the LAA during open chest surgical procedures for patients with pre-existing AF. AtriCure, Inc. received FDA clearance for use of this device in open chest procedures in June, 2010. The CDL continues to contribute to the design and refinement of this device by conducting animal studies to evaluate the efficacy of delivering this device through a minimally invasive surgical approach.

Motion Cancellation System for Robotic Heart Surgery

Significant technical challenges exist in current beating heart surgery, accomplished by use of mechanical stabilization devices attached to the heart. The CDL is teaming up with Cenk Cavusoglu, PhD., in the Department of Electrical Engineering and Computer Sciences at Case Western Reserve University to develop robotic tools for totally endosopic off-pump (no cardiopulmonary bypass [CPB]) coronary artery bypass graft (CABG) surgery using active relative motion cancellation. Sensors deployed onto the heart surface are used to quantify heart motion while the robotic system actively cancels the relative motion between the surgical site on the heart and the surgical instruments. As a result, the surgeon operates on the heart as if it were stationary. This robotic system eliminates the need for CPB, reducing medical costs and eliminating its potential complications. The CDL will perform the in vivo validation studies in an animal model.

Active S ystem to P revent C hest T ube C logging

Chest tubes are commonly used to drain blood and fluids after thoracic surgeries. Today, there is no reliable method to prevent chest tube obstruction, which worsens clinical outcomes. In this project we aim to explore effective solutions for this high-impact clinical issue. We are developing the active system that reduces the blood deposition and clot formation in chest tubes. The active system is expected to reduce drainage-related postoperative complications and improve hospital outcomes.

Whole Chamber Mapping

Atrial fibrillation (AF) is often treated with medications to slow the heart rate to a normal range (known as rate control) or to correct the heart rhythm to normal sinus rhythm (known as rhythm control). Catheter ablation to electrically cut the pathway of the abnormal rhythm is one of the treatment options which can correct AF without the need for medications, and it is critical to the success of simultaneous endocardial whole chamber electrical mapping (from inside of the heart without a need to open the chest). Collaborating with Cleveland Clinic cardiologist Dr. Niraj Varma, electrical mapping of the entire chamber is being developed in animal models to detect the pathway of the abnormal rhythm which should be treated.

Tricuspid Valve Occlusion for Treatment of Tricuspid Valve Regurgitation

A complication of dilated cardiomyopathy secondary to chronic heart failure is an enlargement of the right ventricle and its inlet valve (tricuspid) annulus which results in an inability of the valve to properly close during systole and an increasing regurgitation of blood flow back into the right atrium instead of into the pulmonary artery. Collaborating with Cleveland Clinic cardiologist Dr. Samir Kapadia, an occlusion device is being developed that is placed intravenously with minimally invasive techniques into the center of the tricuspid valve to provide additional surface area onto which the expanded valve can close. The device is permanently fixed in the right ventricle by anchoring it to the ventricle wall with a screw. This device is designed to improve morbidity and mortality compared with the current medical and surgical procedures to treat tricuspid valve regurgitation. We are currently developing this technology in an animal tricuspid valve regurgitation model in order to evaluate its initial safety and feasibility.

 

3. Clinical Study

The Incidence, Classification and Clinical / Economic Impact of Chest Tube Occlusion

The Department of Thoracic and Cardiovascular Surgery (Dr. A. Marc Gillinov) and the Cardiovascular Dynamics Lab have partnered in this initiative collaboration. The incidence of chest tube clogging after cardiothoracic procedures and its associated clinical variables are being studied to reveal the clinical outcomes related to this clogging in cardiac surgery patients. In particular, we hypothesize that tube blockages may be more common in patients with defined excessive post-operative bleeding. Knowing the incidence of chest tube clogging may help to stratify the incidence of chest tube obstruction in patients undergoing cardiac and/or thoracic surgery procedures. This can result in new paradigms for chest tube insertion and maintenance and the need for new chest tube technology in certain classes of surgical patients to improve postoperative outcomes, especially in patients predisposed for bleeding. The study also aims to identify any statistically significant differences in morbidity and mortality within the same subgroup of patients who have had and did not have chest tube obstruction. Finally, results of the study will quantify the economic impact of this complication in terms of the association of chest tube obstruction with poor clinical outcomes and its associated increased costs.

Prognostic Value of Microvascular Assessments in patients treated with ECMO

The current study is a collaboration between of the Department of Thoracic and Cardiovascular Surgery (Dr. Nad e r Moazami) and the Cardiovascular Dynamics Lab. Extra-corporeal membrane oxygenation (ECMO) may temporarily replace the function of the failing heart until heart recovery (bridge to recovery) or until other therapy (heart transplant (HTx), permanent mechanical heart assist), but is a resource-consuming therapy. Successful weaning from ECMO, reported to be less than 50% in adults, is dependent on factors like nature and severity of the heart failure, patient´s age and co-morbidities, as well as institutional skills. In parallel with improvements of the technical equipment for delivery of ECMO, new indications, like on-going heart lung resuscitation with resistant arrhythmia, are emerging. Traditional clinical, biochemical and hemodynamic techniques are used to guide other additional treatment while on ECMO, but these methods have low predictive value related to the chance of successful weaning. The results of the study of skin microvascular assessments with computer assisted video microscopy (CAVM) will be used to predict successful weaning as soon as the patient has been stabilized on ECMO.