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Insertion
of the stretched Inoue balloon catheter over the 0.025" stainless steel
coiled-tip guidewire into the right femoral vein goes smoothly in the majority
of patients. Occasionally, difficulties arise from resistance to the catheter
at the venous access site or interatrial septum, or from catheter trapping
or migration after its insertion into the left atrium.
I. RESISTANCE AT THE GROIN VENOUS ACCESS SITE
Venous Access
Puncture needle angle (Figure 1, A)
To avoid creating a long subcutaneous
tunnel which may pose some resistance during insertion of the balloon catheter,
the puncture needle is angled more vertically than usual during the initial
vascular access (at about 60° to the skin surface instead of 45°).
Access site dilatation
After transseptal puncture and
insertion of the coiled-tip guide wire into the left atrium, the shorter
subcutaneous track is then well stretched with an artery forcep (Figure
1, B) along the guide wire. This is followed by use of the 12F dilator (enclosed
with the Inoue balloon assembly), which is also used to dilate the atrial
septum.
Finally, when inserting the stretched
balloon catheter, firm compression using the flat of the fingertips cephalid
(Figure 1, B) to the puncture site and over the subcutaneous track may be
needed to aid catheter entry.
Figure 1
Resistance at groin access site
At
times, significant resistance is encountered during insertion of the
stretched balloon catheter. This is usually encounted in thin patients
with
much less subcutaneous fatty tissues in the groin. In these cases,
the balloon catheter is inserted into the vein at a more obtuse angle
of about 90° until it touches the posterior venous wall. The catheter
is then tilted more horizontally and advanced over the wire (Figure
2). Thus during the latter process, to facilitate catheter insertion
and avoid bending the guide wire, firm compression should be applied
cephalid to the puncture site and over the subcutaneous track (as
described above), and the guide wire should be held taut by an assistant.
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Figure
2
Vertical Catheter Insertion
Click to View Larger Image |
The alternative
is to use a 180° rotation of the balloon catheter and attempt
to insert the catheter in a more horizontal direction, as in a scooping
motion.
If the above techniques
fails, the subcutaneous track and the vein should be redilated with
a 14F dilator. If these precautionary measures are exercised, the
need for a 14F intravascular sheath for insertion of the catheter
is rare in our experience, even in patients with the right groin scarred
from previous catheterizations. However, one should not hesitate to
use a 14F vascular sheath to avoid bending the guide wire or metal
tube, when a difficulty is encountered during the catheter insertion
process.
It is also important to
note that during insertion of the catheter into the femoral vein,
the catheter should never be twisted, lest the metal tube be
bent. If the tube is inadvertently bent, it should be replaced with
a new one. On the other hand, if the guide wire is bent, the 12F dilator
is reinserted over the wire and carefully left in the left atrium.
The wire is then replaced. |
II. RESISTANCE AT ATRIAL SEPTUM
After atrial septal puncture and
placement of the coiled-tip guidewire in the left atrium, there may be some
difficulty at times in advancing the balloon catheter across the septum,
particularly when the latter is markedly thickened at the puncture site.
When this occurs, forceful action is to be avoided as the catheter may curve
excessively in the inferior vena cava, resulting in abdominal discomfort
for the patient. Rather, the balloon catheter should be turned slightly,
usually in a clockwise direction as it is pushed forward (screwdriver
maneuver) to overcome septal resistance.
In rare instances when this method
also fails, the septum is redilated with the dilator. After passage
across the septum, it is also important not to push the catheter tip up
against the left atrial roof, or the guidewire may be bent into an acute
angle, making subsequent catheter manipulation difficult.
III. DEEP CATHETER PLACEMENT IN LEFT ATRIUM (Figure 3)
After
transseptal access, the balloon catheter is introduced under the frontal
view into the left atrium over the coiled-tip guide wire to form a
large loop with the tip medial to the mitral orifice,
pointing to a 6 to 7 o'clock direction (Figure 3). This placement
has the following advantages upon removing the guide wire as well
as when the stylet is inserted to the catheter tip: 1) the catheter
thus positioned is less likely to flip to the left atrial appendage
area; 2) the catheter will not enter the pulmonary veins; and
3) in subsequent manipulations to cross the mitral valve, because
the catheter has already been advanced deep into the atrium, it will
need only to be withdrawn. Thus, |
Figure
3
Deep Catheter Placement in
Left Atrium
Click to View Larger Image |
| the mitral valve
crossing is attempted first with the vertical method, and potential
catheter entrapment by a tough septum, which is encountered only during
catheter advancement, is avoided (see Valve Crossing and Catheter
Entrapment at Atrial Septum, below. |
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