Implant procedure
The patient shall be prepared for cardiac hybrid procedure according to
hospital’s standard procedures. Intraoperative transoesophageal
echocardiography (TEE) is required to provide procedural assistance,
monitor LV and valve function, and evaluate myocardial anchor implant
placement.
A cell salvage system, standby cardiopulmonary bypass, external
defibrillator pads, meticulous control of ACT and serum
K+ and Mg2+ add to patient safety.
We are describing the procedure step-by-step:
- Percutaneously access the right internal jugular (RIJ) vein.
- Insert a 14F Introducer into RIJ and advance into the superior vena
cava (SVC) or right atrium (RA) (Figure 3).
- Determine location of incision by placing an instrument under
fluoroscopy at the desired location and ensure that the position
allows access to the LV apex and placement of the most basal anchor
pair. The incision should be placed over the intercostal space that
gives a direct line from the antero-lateral wall 5-6 cm above the apex
of the LV and 1-2 cm above the very apex of the RV; in general, the
medial aspect of the incision should be at the level of the patient’s
areola. This imaging should be repeated before actually entering the
interspace.
- Perform the thoracotomy.
- Remove extra-pericardial fat and open the pericardium under direct
vision.
- Identify aneurysm (scar) margins and epicardial landmarks including
LAD and cardiac apex.
- Place a “leash” or tethering mechanism to manipulate the heart. The
“leash” consists of a 2-0 double pledgeted, horizontal mattress
polypropylene suture with a tourniquet. Suture should be placed in the
scar tissue of the heart using suture and pledgets appropriately deep
in the scar to prevent pulling through the wall of the heart. The site
of the leash should be about half way between the lateral scar margin
and the LAD at the level of the RV-apical anchor on the LV epicardium.
Additional leashes may be placed in the scar as necessary to allow
appropriate cardiac manipulation. Leashes should be placed only in
scar intended for exclusion.
- Heparinize the patient maintaining an ACT of 300 seconds or greater.
Float a Swan-Ganz catheter through the 14Fr sheath up to the pulmonary
artery (PA).
- Advance a 0.025 Jagwire™ through the Swan-Ganz catheter and keep it on
the PA.
- Advance a 7Fr multipurpose (MP) catheter with a EnSnare™ endovascular
snare system inside and open it in the RV apex (Figure 4) .
- Perform a RV gram to confirm the position of the EnSnare™
- Place a 7 cm 18 gauge straight needle on the scarred epicardium to
identify landmarks and needle puncture direction. (Caution: avoid
placing needle within healthy myocardium).
- Puncture the needle through the epicardial surface and redirect it
towards the selected septal site as directed by the EnSare™ in the RV
apex; (confirm LV wave form with pressure measurement). Confirm needle
is in the RV using injection of contrast within the needle(Figure 5) .
- Advance a 0.032” wire through the needle and snare it with the
EnSnare™ under fluoroscopy.
- At this point, the 14Fr sheath is advanced to the RV, near the
interventricular septum. The 0.025” Jagwire™ can be also removed.
- Remove the straight needle and advance a 6Fr Brite tip catheter
through the 0.032” wire and into the RV (confirm scar location).
Tactile feedback should reinforce the catheter’s passage through scar.
This is done under fluoroscopy and TEE should be continuously looking
at any changes in tricuspid regurgitation change from baseline(Figure 6) .
- Exchange the 0.032” wire with a 0.014” through a 6Fr standard
multipurpose catheter. This is done in the surgical side.
- At this point, the 6Fr Brite tip catheter must be inside the 14Fr
sheath.
- Place the Internal Anchor assembly over the 0.014” guidewire, and
embed the OWTI tip into the end of the guiding catheter; place a small
clamp on both exposed ends of the 0.014” guidewire – one where it
exits the OWTI on the jugular side of the patient, and the other where
the guidewire exits the guiding catheter at its hub. (This maneuver
creates a single entity out of the OWTI and the guiding catheter so
they may be advanced from the jugular access on the patient’s right
side, to the epicardial access on the left side).
- Advance the OWTI/guiding catheter combination through the 14Fr, and
then through the 6Fr Brite tip, which is tranversing two walls of the
LV. During this maneuver, the 14Fr introducer must be kept in contact
with the right side of the septum, with the tip of the 6Fr Brite tip
inside the 14Fr lumen. The 0.014” guidewire and guiding catheter may
be removed as soon as any part of the wire becomes exposed outside the
6Fr Brite tip at the epicardial location (Figure 7).
- The tip of the 14Fr introducer, which has been essentially in contact
with the septum, is retracted to reveal the anchor when the OWTI has
been advanced to bring the anchor into immediate proximity of the
septum.
- Carefully lay down the hinged, retrievable internal anchor onto the
septum, such that the hinged surface is lying in position on the
septum. Gentle tension must be maintained continuously on the tether
from the LV side. With the hinged anchor laying on the septum, the
OWTI is cut in the rectangular portion of the tether (leaving as much
of the tether length as possible); remove the 6Fr Brite tip. The
external anchor is placed over the tether and advanced to the
epicardial surface. (Bleeding may occur briefly after removal of the
6Fr sheath; contact between the external anchor and the epicardium
generally creates hemostasis). Then use the force gauge to bring the
two walls of the LV into apposition (Figure 8).
- Assess hemodynamics, LV configuration (by TEE), and tricuspid valvular
function (by TEE); if appropriate, release anchor from Flex Catheter,
leaving it in position against the right side of the septum.
- Retract the 14Fr sheath at least to within the RA proximal to the
tricuspid annulus, but ideally to the cavo-atrial junction immediately
after successful deployment and release of the hinged, retrievable
internal anchor onto the septum.
- If there are no more RV anchors anticipated, leave the walls in
contact-plus-1 (one) Newton (using the force gauge). If more are
planned, release the external anchor to allow separation between the
endocardial surfaces to avoid distortion of the LV chamber for
subsequent anchor placement.
- Repeat steps 13-22 for each LV-RV anchor pair.
- When it is determined that the next anchor should be LV-LV (i.e., at
the LV apex with no further space in the RV apex), retract the
introducer from the RV, then oppose the walls with existing anchor
pairs into contact plus 1-2 Newtons, (thus rendering the geometry of
the final, reshaped LV except for the apex). Caution: Using excessive
force could lead to tissue erosion or anchor migration, it is critical
to use the force gauge to ensure proper force to the anchors is being
applied.
- Using the LV Apical needle in a standard surgical needle holder, load
the needle such that it is at a 10 to 15-degree angle from the needle
holder shaft.
- With visibility gained from manipulation of previous anchor pairs,
drive the LV needle across the cardiac apex from right-to-left.
- Retrieve the needle tip. Lay down the hinged anchor on the right side
of the apex and cut the tether at or near the needle to allow
placement of an external anchor for hemostasis. Check all anchor
positions fluoroscopically for alignment (Figure 9).