Balloon Tip Catheters
In another study, an 80-cm balloon-tipped 6-Fr catheter (Pressure
Products, Model BVCS 6180, San Pedro, CA) (Figure 14 ) was
inserted into the right jugular veins of two dogs and advanced to CS.
Their left main coronary arteries were also engaged through a 5-Fr AL2
catheter. A small amount of contrast was injected to confirm the CS
occlusion after inflation of the balloon followed by its deflation to
clear the contrast agent from the CS. Concurrently with contrast
injection, the balloon located in CS was inflated and manual blood
suction into a heparinized syringe was performed for 30 seconds.
Captured contrast was calculated according to grayscale analysis using a
polynomial regression curve. Meyer and colleagues suggested due to the
presence of small lumen in currently available CS balloon catheters, the
flow rate is low leading to enhanced withdrawal times. Thus, increasing
the flow capacity of available catheters might be associated with
heightened contrast removal efficiency. They also claimed this technique
can be applied in any circumstances when a noxious agent should be
administered in a selected organ if the draining venous system can be
accessed (89).
On the other hand, different catheters are used in humans. Danenberg et
al. used a balloon-tipped catheter with two lumens and multiple distal
holes (Reverse Berman Angiography Catheter, 7 Fr, Arrow Int, Reading,
PA, USA) (Figure 15 ) for accessing the CS. They occluded CS
before contrast injection and blood was manually extracted 5-7 seconds
post coronary contrast administration and the balloon was deflated for
20-30 seconds after contrast disappearance shown by fluoroscopic images.
Extracted contrast concentration was measured by assessing reduction in
Hct levels in collected samples compared with simultaneous Hct levels
from aorta using the following formula: (1 – Hct in CS extracted blood
/ Hct in the aorta) * collected blood volume. Although CS was
successfully accessed in all seven enrolled patients, the catheter
slipped out of the CS led to procedure failure in four participants.
However, the entire process was one without difficulties in the
remaining three subjects. Another issue was related to fluoroscopy time.
The extra time needed for CS cannulation increased the mean fluoroscopy
tome in comparison to routine interventions. However, they reported this
method can be done in most catheter laboratories with no special
equipment. The additional benefit was associated with intermittent CS
obstruction. It has been reported that periodic occlusion of CS
decreases coronary artery blood flow regardless of the aortic pressure
or CS
obstruction (95,96) .
This reduced flow could be used to decrease contrast volume per
injection. Therefore, a reduced amount of used contrast agent and
significant contrast extraction can additively decrease CIN risk. They
also suggested using superior vena cava to enter the right atrium for CS
cannulation as a common technique. However, using femoral access might
be quite difficult with standard catheters and they used Simmons II
catheter for CS
engagement (90).