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Inadequate POT
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Proximal 2nd POT was not performed (as indicated when the pMV stent is longer than the POT balloon length)
Proximal 2nd POT was incorrectly performed: POT too small/too distal
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Proximal re-POT
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Enhanced angiographic visualisation to increase precision of POT balloon positioning
Optimal POT balloon sizing
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SB/aSB occlusion
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POT balloon position (distal to the carina)
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Rescue balloon jailing technique (see Step 1)
Re-POT with a larger balloon
Rewiring the SB/aSB (see Step 1)
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Perfect POT balloon position immediately proximal to the carina2
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pMV dissection
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POT balloon position (proximal to the edge of the pMV stent)
Oversizing of the POT balloon
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Additional stent implantation at the edge of the pMV stent
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pMV DES length longer than the POT balloon (6-8 mm)
Availability of 6-8 mm long POT balloons in the cath lab
Intracoronary imaging to evaluate disease extent and vessel size
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pMV stent elongation in LM stenting31
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Excessive stent overexpansion by POT, commonly needed during LM stenting, with 1 mm of absolute overexpansion resulting in 2.2 mm elongation, as compared to nominal stent length31
Interaction between the POT balloon, stent and bifurcation geometry:
a) the overexpansion with tight “balloon-to-strut” interaction results in stretching of crowns and connectors longitudinally [31
b) the “correctly positioned” POT balloon slides backwards during opening (“melon seed effect”), pulling stent struts back from the distal MV ostium3 [1
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Failing to recognise this phenomenon may lead to dynamic protrusion into the aorta, which has potential side effects such as strut damage induced by the guiding catheter, potential nidus for thrombus formation, plus difficulties with ostial catheter engagement and wire advancement upon secondary catheterisation31
Imaging-guided detection by IVUS/OCT/stent enhancement techniques (stentviz, stent boost etc.) and correction by POT of any strut damage/longitudinal stent deformation induced by the guiding catheter
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Rather than aiming for a perfect marker-on-carina position of the POT balloon, a modified (somewhat more proximal) position should be considered, adapted to the diameter mismatch and conus length of the available balloon31
Instead of aiming for a perfect aorto-ostial position of the stent, potential proximal elongation should be accounted for, with positioning of the stent slightly within the ostium of the LM stem31
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Difficulty in removing the jailed wire after POT with:
1) Fracture of the jailed wire
2) Longitudinal deformation of the MV stent (a) LM vs (b) non-LM
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1) The calcification of the vessel wall, the length of the trapped wire, and high pressures used at the MV stent deployment have been suggested as predictors of jailed wire rupture
2) (a) Pull-back of the jailed wire or a partially deflated balloon may lead to forward movement of the guide catheter potentially causing longitudinal stent deformation or ostial coronary dissection
(b) MV stent deformation caused by guiding catheter extension (e.g., GuideLiner [Teleflex]).
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The best way to free an entrapped SB/aSB guidewire is to advance a balloon or microcatheter over it as far distally as possible before retracting it, which in most cases leads to guidewire retrieval. Inflating a small balloon advanced as distally as possible can also help remove an entrapped guidewire.
1) Fracture of the jailed wire: various solutions ranging from simply leaving the segment of wire in place to surgery for removal, but first efforts should be made to remove the wire percutaneously using: 1) a snare loop to remove a distal fractured wire especially if it is floating in the aorta or 2) the tangling technique with the help of 2-3 workhorse (e.g., BMW [Abbott]) wires acting as rescue wires.
2) Longitudinal stent deformation: IVUS/OCT guided POT and additional stenting (stent-in stent)35
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Fracture of the jailed wire:
Polymer-coated wires seemed to be more resistant to retrieval damage than non-polymer-coated wires37
Optimal plaque modification with NC balloon dilatation, cutting/scoring balloons or rotational/orbital atherectomy in calcified lesions
Short length of the jailed wire
Lower pressures during the MV stent deployment in calcific CBL
Avoid jailing the wire in multiple overlapping stents
Avoid oversized stent and/or high-pressure post-dilatation after stenting
Longitudinal stent deformation:
in LM: backward traction (or sometimes near complete disengagement) of the guide catheter from the LM ostium36
in non-LM: avoid forceful removal of a jailed wire and the contact between the tip of a guide catheter extension and the proximal edge of the MV stent
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BMW: balance middleweight; CBL: coronary bifurcation lesion; DES: drug-eluting stent; IVUS: intravascular ultrasound; LM: left main; MV: main vessel; NC: non-compliant; OCT: optical coherence tomography; pMV: proximal main vessel; POT: proximal optimisation technique; PS: provisional stenting; SB/aSB: side branch/assigned side branch
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