Four Catheter positions you are likely to encounter when examining echocardiograms from patients supported with the Impella CP Catheter.
For optimal positioning of the Impella CP Catheter, the inlet area of the catheter should be 3.5 cm below the aortic valve annulus and well away from papillary muscle and subannular structures. The outlet area should be well above the aortic valve. If the Impella CP Catheter is correctly positioned, echocardiography will likely show the following:
If the Impella CP Catheter is positioned too far into the left ventricle, the patient will not receive the benefit of Impella CP Catheter support. Blood will enter the inlet area and exit the outlet area within the ventricle. Obstruction of the Impella CP Catheter inlet area can lead to increased mechanical forces on blood cell walls and subsequent hemolysis, which often presents as dark or blood-colored urine. If the Impella CP Catheter is too far into the left ventricle, echocardiography will likely show the following:
If the inlet area of the Impella CP Catheter is in the aorta, the patient will not receive the benefit of Impella CP Catheter support. The catheter will pull blood from the aorta rather than the left ventricle. In addition, suction is possible if the inlet area is against the wall of the aorta or valve sinus. If the inlet area of the Impella CP Catheter is in the aorta, echocardiography will likely show the following:
If the inlet area of the Impella CP Catheter is too close to or entangled in the papillary muscle and/or subannular structures surrounding the mitral valve, it can affect mitral valve function and negatively impact catheter flow. If the inlet area of the catheter is lodged adjacent to the papillary muscle, the inflow may be obstructed, resulting in suction alarms. This positioning is also likely to place the outlet area too close to the aortic valve, which can cause outflow at the level of the aortic valve with blood streaming back into the ventricle, resulting in turbulent flow and hemolysis. If the Impella CP Catheter is too close to or entangled in the papillary muscle, echocardiography will likely show the following:
When moving a patient supported with an Impella CP Catheter, it is important to monitor catheter migration. Adding color Doppler to an echo is another way to verify catheter position. If the Impella CP Catheter is correctly positioned, a dense mosaic pattern of turbulence will appear above the aortic valve near the outlet area of the catheter (see the image below). If, however, the echocardiogram reveals a dense mosaic pattern of turbulence beneath the aortic valve, this likely indicates that the outlet area of the catheter is in the wrong position, that is, the catheter is too far into the ventricle or entangled in papillary muscle. (Note: If using transesophageal echocardiography [TEE], look for the mosaic patterns in the same locations relative to the aortic valve and Impella CP Catheter outlet area.)