Radiology of Intra-Aortic Balloon Pump Catheters

Abstract

Radiographs play an important role in ascertaining appropriate placement of the intra-aortic balloon pump catheter. This imaging essay highlights correct and incorrect positioning of these catheters, with emphasis on the variability of radiopaque markers used with different catheter models and on axillary versus femoral catheter placement routes. Keywords: Conventional Radiography, CT, Percutaneous, Cardiac, Vascular, Aorta, Anatomy, Cardiac Assist Devices, Catheters © RSNA, 2022.

Keywords: Anatomy; Aorta; CT; Cardiac; Cardiac Assist Devices; Catheters; Conventional Radiography; Percutaneous; Vascular.

Figure 1:

Intra-aortic balloon pump catheter. The distalmost tip is rigid (black arrowhead), with a radiopaque marker near the distal tip of the balloon (black solid circle). The balloon is deflated but can be well seen between the markers. If present, a second radiopaque marker (black dashed circle) is positioned just proximal to the balloon (black arrowhead). The more proximal catheter (black arrow) extends off the superior margin of the image to the pump.

Figure 2:

(A) Femoral-approach positioning of an intra-aortic balloon pump catheter on a bedside frontal chest radiograph, with single distal marker (in white circle) projecting approximately 1 cm below the top of the aortic knob (dashed white curve). The carina is also marked with the dashed white angle. (B) Diagram demonstrates the layout of the catheter placed by a femoral approach. (Fig 2B used with permission of Mayo Foundation for Medical Education and Research, all rights reserved.) (C) Fluoroscopic overhead image of the distal marker at time of placement by the interventionalist, showing the distal marker (in white circle), top of the aortic arch (dashed white curve), and the carina (dashed white angle).

Figure 3:

(A) Frontal radiograph and (B) oblique sagittal slab maximum intensity projection CT image reconstruction demonstrate the relationship of the carina with the aortic knob. The descending aorta is to the right of the CT image. In both images, the carina lies at the level of the solid white line. A level measured 1 cm below the top of the aortic knob is indicated by the dashed white line. The intra-aortic balloon pump tip and its marker should project between these two levels. Also marked on both images is the origin of the left subclavian artery (white arrowhead) nearest the top of the arch.

Figure 4:

(A) Frontal radiograph shows the distal, doubled marker (in solid white circle) after femoral-approach catheter placement. On this catheter, the distalmost portion of the distal marker is less dense than that of the neighboring portion, which provides a sense of directionality to the catheter. Note, this catheter has a second, smaller marker just proximal to the balloon (in dashed white circle). Some catheters have similar-appearing proximal and distal markers that make directionality difficult to determine. (B) Diagram of the relationship between the two radiopaque markers. (Fig 4B used with permission of Mayo Foundation for Medical Education and Research, all rights reserved.)

Figure 5:

Images in a 61-year-old man measuring 183 cm in height. (A) Frontal radiograph centered on the diaphragm to include both the distal (solid white circle) and proximal (white dashed circle) markers of a femoral-approach catheter that measured 258 mm in length. The distal marker is appropriately positioned, with the proximal marker projecting over the superior aspect of the L2 vertebral body. (B) Sagittal slab maximum intensity projection reconstruction image obtained just before catheter placement demonstrates the relationship of the celiac (white arrow) and superior mesenteric artery (white arrowhead) origins relative to the L1 and L2 vertebral bodies.

Figure 6:

Frontal chest phantom image with three different overlying intra-aortic balloon pump catheters from the same manufacturer, with distal markers in solid white circles and proximal markers in dashed white circles. There is no standard for markers. While all have two markers, which is not always the case, note that catheter 3 has proximal and distal markers that are very similar, while catheters 1 and 2 have a longer, dual-density distal marker.

Figure 7:

(A) Frontal chest radiograph depicts a well-positioned femoral-approach dual-density distal tip marker within the descending aorta. (B) The magnified insert accentuates the relatively lucent distalmost portion of the catheter marker and the adjacent, more proximal dense portion of the marker. From a femoral approach, if these portions of the marker were reversed, with the denser portion located cranial to the less dense portion, the catheter would be positioned in the ascending aorta. Knowledge of this dual-density distal marker is often helpful, as is later shown in Figure 14.

Figure 8:

(A) Frontal chest radiograph demonstrates how the diminutive intra-aortic balloon pump (IABP) marker is often hard to resolve from the neighboring coronary bypass graft clips and other objects. (B) Same image with the IABP marker in the white circle.

Figure 9:

Two images in the same patient, with acquisition separated by several minutes. (A) Bedside frontal chest radiograph image of the chest and abdomen centered on the diaphragm to better visualize both markers on the intra-aortic balloon pump catheter placed via a femoral approach. The caudal marker (white dashed circle) is visible in the abdominal aorta, projecting over the L4 vertebral body. The position of this caudal marker suggests a low-lying catheter. (B) Interestingly, the frontal chest radiograph demonstrates how motion at time of image exposure in A can completely obscure the more cranial marker (white solid circle). As shown, it lies below the level of the carina (lower than expected) and accounts for the low-lying caudal marker observed in A.

Figure 10:

Diagram of axillary-approach catheter with the distal balloon marker projecting over the mid aorta. If a single-marker catheter is employed by this approach, the balloon positioning cannot be verified on a radiograph. (Used with permission of Mayo Foundation for Medical Education and Research, all rights reserved.)

Figure 11:

Marker positions for (A, B) femoral and (C, D) upper- (axillary-) approach intra-aortic balloon pump catheters. The distalmost tips are marked with solid white circles and proximal markers with dashed white circles in B and D. Note that in A and B, the cranial marker represents the distal tip of the catheter in A and B and the proximal tip in C and D. The balloons are appropriately positioned in both frontal radiographs. An access sheath (white arrows in D) is often seen with the axillary approach. (Fig 11A and C used with permission of Mayo Foundation for Medical Education and Research, all rights reserved.)

Figure 12:

Images in a 44-year-old man with heart failure. (A) Initial frontal chest radiograph demonstrates the proximal marker from an axillary-placed intra-aortic balloon pump (IABP) catheter (dashed white circle), originally thought to be a clip. This presumed “clip” projects above the aortic arch. The presence of an IABP catheter was not recognized by multiple radiologists for several days, even after more proximal migration of the proximal marker into the left axillary artery on (B) the follow-up radiograph. On close inspection, the follow-up radiograph demonstrates a high distal marker (solid white circle), a high proximal marker (dashed white circle), a faint axillary sheath (white arrows), and an inflated balloon projecting through the arch (white arrowheads).

Figure 13:

Images in a 66-year-old man with heart failure. (A) Frontal chest radiograph that was initially labeled as “normal, with tip projecting over the arch.” While this was technically correct, the radiologist did not recognize that this was an axillary-approach catheter with a dual-marker distal tip (solid white circle) and a second proximal marker (white dashed circle). Had this been a femoral-approach catheter, the distal dual marker would project over the ascending aorta (note the more lucent part of the marker that is distalmost on the catheter is reversed from that expected for a femoral-approach tip in the descending aorta). Also, the proximal marker of the catheter projects over the proximal arch. The distance between the markers is only several centimeters, so clearly the catheter is folded upon itself. This distal marker should be at or off the inferior margin of view for a correct axillary-approach placement. A sheath (white arrows) can be seen overlying the left axilla. (B) Oblique sagittal unenhanced average intensity projection chest CT image demonstrates abnormal positioning of the balloon (dashed white line).

Figure 14:

Images in an 80-year-old woman with heart failure. Frontal chest radiographs depict a misplaced catheter. (A) The inflated balloon (white arrowhead) during diastole and (B) the deflated balloon during systole confirm the balloon's presence in the arch, which was placed via an axillary approach. The high distal markers (solid white circle), low proximal markers (dashed white circle), and short distance between the markers further confirm the abnormal position of the balloon.

Figure 15:

Images in a 38-year-old woman with heart failure. (A, B) Frontal chest radiographs that emphasize the directional nature of the distal marker (solid white circle). (A) The axillary-placed catheter distal tip is in the expected position, with the more lucent radiopaque portion distalmost. (B) The catheter tip has folded back on itself, with the densest portion of the distal marker now distal. Note that the distance between the distal and proximal (dashed white circle) markers has shortened. (C) Oblique coronal slab CT image with arterial phase contrast enhancement demonstrates the distal tip flipped back upon itself (curved white arrow). The metal tip should project distal to the balloon (at the base of the white arrow), not along the periphery of the distal balloon. The left axillary sheath is also marked with white arrows in B.