Percutaneously and Surgically Inserted Ventricular Assist Devices




Key Points





  • Intra-aortic balloon pump position is readily verified by chest radiography, because the tip is radiopaque. The tip should be located at the very distal aortic arch or proximal descending aorta.



  • Percutaneously inserted ventricular assist devices are radiographically apparent, and at least in a comparative sense, their position can be verified by chest radiography.



  • The positions of cannulae of extracorporeal membrane oxygenation (ECMO) systems can be verified by abdominal and chest radiography.



  • The cannulae of ventricular assist devices are also radiographically apparent.





Percutaneous Devices


Pulsatile Devices: Intra-aortic Counterpulsation Balloon ( Figs. 24-1 to 24-7 )


The tip of an intra-aortic balloon (which is highly visible because of its metallic marker) should be at least 4 cm below the “knuckle” of the aorta (i.e., below the left subclavian artery). The balloon appears as a cylindrical lucency if the radiographic exposure happened to be while it was inflated in diastole. Widening or haziness of the aorta suggests aortic dissection as a complication of the catheter. Incorrect insertion into the inferior vena cava is suggested by the shadow of the catheter lying to the right of the patient’s vertebral column.




Figure 24-1


A 75-year-old male presented in acute heart failure due to a non–ST-segment elevation myocardial infarction (non-STEMI) (left upper image) . He underwent coronary angiography, which revealed an occluded right coronary artery and 95% left mainstem stenosis. An intra-aortic balloon pump was inserted, with the radio-opaque tip verified to be in the correct position (right upper image) , and cardiac surgery consulted. The patient stood up at the bedside, despite the inserted balloon pump. Chest radiography revealed its acquired malposition with the radio-opaque tip visualized in the lower thoracic aorta (left lower image) ; it was repositioned at the bedside. Follow-up chest radiography demonstrated that the tip is slightly high in the aorta and deflected medially by the aortic wall (right lower image) . Note the difference in the upper and lower right images with respect to the balloon pump tip marker position.



Figure 24-2


The radiographically apparent intra-aortic counterpulsation balloon catheter tip is in the correct position. By chance occurrence, the radiograph was obtained in early or mid-diastole when the balloon was inflated, and the size and length of the balloon are apparent. The endotracheal, nasogastric, and chest tubes are in the correct positions.



Figure 24-3


The intra-aortic counterpulsation balloon catheter tip is too high, as the marker is at the top of the distal arch.



Figure 24-4


The intra-aortic counterpulsation balloon catheter is slightly low; the tip of the marker is a few centimeters lower than the aortic arch.



Figure 24-5


The intra-aortic counterpulsation balloon catheter is frankly low; the tip of the marker is multiple centimeters lower than the distal aortic arch. The endotracheal and nasogastric tubes are in the correct positions.



Figure 24-6


The intra-aortic counterpulsation balloon catheter tip is low; the tip of the marker is multiple centimeters lower than the distal aortic arch. The endotracheal, nasogastric, and chest tubes, as well as the pulmonary artery catheter are in the correct positions.



Figure 24-7


The tip of the marker of the intra-aortic balloon is seen on the right side of the heart, and the aortic arch is left-sided. The tip lies in the right atrium due to misinsertion into the femoral vein, not the femoral artery.


Continuous Flow Devices: Impella 2.5


The Impella 2.5 (2.5 L/minute support), a continuous flow ventricular assist device, provides continuous flow assist comparable to that of intra-aortic balloon pump. It is percutaneously inserted from the groin. Radiographically and fluoroscopically, the pigtail tips are apparent, the mechanical intake device and the mechanical output device are obvious and the conduit between the two is fairly obvious, and the more proximal catheter is marked by a faint radiopaque stripe. The pigtail tip holds the intake back from the apical wall; the intake housing draws ventricular cavity blood into it, and the output housing with the impeller pump draws blood through the intake housing and ejects it into the aortic root on the far side of the aortic valve, offloading and resting the left ventricle. On a frontal radiograph, the pigtail is directly left inferiorly and the conduit initially follows the same line before it angulates vertically or vertically/leftward up the aortic root.




Surgically Inserted Ventricular Assist Devices


There are several models of surgically inserted (left and right) ventricular assist devices with widely different designs and radiographic appearances.


Impella 5.0


The Impella 5.0 (5.0 L/minute support) is inserted by surgical cutdown or via sternotomy ( Graphic 24-1; Figs. 24-8 to 24-13 ). There are two models. The Impella 5.0 is similar to that described previously. The Impella 5.0 LD is similar but without the pigtail component.


Apr 10, 2019 | Posted by in General Surgery | Comments Off on Percutaneously and Surgically Inserted Ventricular Assist Devices
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