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Small LVAD demonstrates good clinical, hemodynamic outcomes in pilot study
The Synergy Micro-pump is the size of an AA battery.
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A pump weighing 25 grams provided partial circulatory support and improved hemodynamics and cardiac function when implanted in patients with medically refractory heart failure.
“We believe that this pump has the potential to expand the use of mechanical circulatory support to a much larger population of patients with less severe but still critically-suffering patients with HF,” said Daniel Burkhoff, MD, PhD, adjunct associate professor at Columbia University, New York, and chief medical officer of CircuLite, Inc., developer of the Synergy. Traditional ventricular assist devices provide full support and pump 5-7 liters of blood per minute or more, whereas the Synergy pumps 2.5 to 3 liters of blood per minute.
Researchers implanted 16 patients with The Synergy Pocket Micro-pump (CircuLite). The patients were predominately male, mean age 52 years, with a mean baseline ejection fraction of 20%. The patients had NYHA class IIIb and early class IV HF, despite optimal medical therapy.
Before implantation, their mean arterial pressure was 72 mmHg, mean pulmonary capillary wedge pressure was 29 mmHg, and mean cardiac index was 1.9 L/min/m2. The duration of their partial support was a mean of 90 days and ranged from six to 213 days.
Thirteen of the 16 patients were alive at three months. Of these, nine patients had right heart catheterization after an average of 10 weeks of support. Increases in mean arterial pressure (67 vs. 80, P=.01) and cardiac index (2.0 vs. 2.8, P=.01) with large reductions in capillary wedge pressure (30 vs. 18, P=.001) were observed. In five patients who underwent testing, peak VO2 increased by 4.5 ml/kg/min (9.6 vs. 14.1, P=0.01).
Burkhoff presented the results Monday during an Emerging Technologies late-breaking clinical trial session. – by Judith Rusk
These initial results of this clinical pilot provide a proof of concept in at least a few patients. Partial support will provide important long-term …hemodynamic support in the 'less sick,' and the so-called INTERMACS/NYHA class IV patient group. There’s no question that the ability of placing this device off cardiopulmonary bypass in the beating heart, through a small right thoracotomy a few centimeters long, should lower the bar to implantation if our problem with thrombosis has truly been overcome and the complication rates remain low. It’s interesting to note that despite 10 prompt thromboses you only had one stroke and no deaths, which again indicates it’s sort of different from the thombosis that would occur in a replacement pump which is if anything a more morbid procedure and more likely to cause someone to die.
– Michael A. Acker, MD
Chief, Cardiovascular Surgery Division,
University of
Pennsylvania Medical Center, Philadelphia
For more information:
- Burkhoff D. First proof of long term hemodynamic benefits of partial ventricular support in patients with severe HF. #407. Presented at: American College of Cardiology 58th Annual Scientific Sessions; March 29-31, 2009; Orlando, Fla.