Introduction:
Cardiogenic shock is associated with a high mortality and patients often require temporary mechanical circulatory support. In addition, we deal with an increasing number of patients with complex multi-vessel diseases who cannot undergo surgical myocardial revascularization due to their comorbidities. Those patients could benefit from a protected PCI using a temporary mechanical assist device. The available LVAD systems have specific advantages and disadvantages. Therefore, we aimed to develop a percutaneous implantable, assist device that unloads the LV in a pulsatile way, which minimizes the disadvantages of the already established systems.
Methods:
The PERKAT-LV („PERkutane KATheterpumptechnologie“)device consists of a self-expanding nitinol pump chamber which is covered by foils. Those foils carry multiple outflow valves at the proximal part of the pump chamber. A flexible suction tube with a pigtail-shaped tip and inflow holes are attached to its distal part. The system is designed for 16F percutaneous implantation via the femoral artery. Pulling back the outer sheath unfolds the nitinol chamber in the descending aorta while the flexible suction tube bypasses the aortic arch and ascending aorta with its tip in the left ventricle. In the second implantation step, a standard IABP balloon is placed into the pumping chamber and connected to an external IABP console. Balloon deflation generates a blood flow from the left ventricle into PERKAT LV. During balloon inflation, blood leaves the system through the outflow foil valves in the descending aorta. Positioning and schematic drawing of PERKAT-LV is demonstrated in Figure 1.
Results:
In-vitro studies using a prototype of the PERKAT LV device were performed using a liquid bath filled with blood analogue which consists of 74.7% (v/v) distilled water, 25.3% (v/v) glycerol, and 0.032% (w/v) xanthan gum. We achieved a viscosity of 3.05 mPa/sec (at 37°C), which represents a standard value of blood with a hematocrit of 45%. PERKAT LV was tested in different afterload settings (0, 40, 80 and 120 mmHg) using a standard 30 ccl IABP balloon and varying inflation/deflations rates (70, 80, 90, 100, 110 and 120/min). We detected flow rates ranging from 2.0 to 3.0 L/min depending on the afterload setting and inflation/deflation rate (Table 1).
Conclusion:
The novel percutaneously implantable and pulsatile working PERKAT-LV device offers left ventricular unloading and circulatory support of up to 3.0 L/min in a feasibility study. At the moment, the system is developed further and extensively studied under in vitro and in vivo conditions.
Based on the current results, we believe that the system is a promising novel approach for percutaneous application of temporary left ventricular mechanical support.
Table 1
|
|
Afterload/Preload | |||
|
Inflation/Deflation Rate (bpm) |
0/0 mmHg |
40/10 mmHg |
80/10 mmHg |
120/10 mmHg |
|
70 |
2.7 |
2.6 |
2.2 |
2.1 |
|
80 |
2.8 |
2.6 |
2.4 |
2.2 |
|
90 |
3.1 |
2.8 |
2.6 |
2.3 |
|
100 |
3.1 |
2.9 |
2.7 |
2.4 |
|
110 |
3.2 |
2.9 |
2.7 |
2.5 |
|
120 |
3.3 |
3.0 |
2.8 |
2.4 |
Flow rate (L/min) dependency from inflation/deflation rate and pre-specified afterload settings using a 30 cc IABP balloon (Bpm beats per minute).
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