Complications lost scaffold: a dislodged bioresorbable scaffold

Clinical presentation

• 47-year-old male with stable angina, electively admitted for staged PCI to the proximal-mid left anterior descending artery (LAD)
• Past cardiac history:
  • PCI with DES to left circumflex artery 1 month ago
  • PCI with DES to proximal LAD 2 years ago
• PCI strategy is to plan bioresorbable scaffold to mid LAD in view of:
  • Young age
  • Intention to preserve viable LAD target for potential future CABG

Procedure

Pre-PCI angiogram and OCT

Pre-PCI OCT showed diffuse disease from proximal to mid LAD, with mainly fibrous plaque and small amounts of calcium.

Lesion length measured 37mm and the intended strategy was to use 2 overlapping Mg-BRS of 3.5 x 20mm and 3.0 x 20mm respectively.

Lesion preparation

Despite pre-dilation with a 3.5mm NC balloon, a 3.0 x 20mm Mg-BRS could not be advanced past the protected diagonal branch (*) to the distal landing zone. This was possibly due to inadequate lesion preparation or entanglement with the diagonal branch guidewire. The BRS delivery system was removed to allow further pre-dilation.

BRS dislodgement

However, friction was felt on pulling the BRS back into the guider and on inspection of the delivery system once outside the body, the undeployed BRS was not seen on the stent balloon.

Dislodged Mg-BRS on OCT

The radiolucent, dislodged BRS could not be seen fluoroscopically. The diagonal branch wire was repositioned to the distal LAD and OCT was performed on this wire to ascertain the dislodged scaffold position.

OCT confirmed an undeployed Mg-BRS (*) in the LM-LAD. The proximal edge of the scaffold (B) was located just at the guider tip, suggesting that this was the point at which the Mg-BRS was sheared off its balloon during withdrawal. The BRS was also shortened to 16mm.

OCT assessment

OCT assessment

Twisting wire technique

To retrieve the dislodged Mg-BRS, the twisting wire technique was attempted using the two existing wires (A). A third wire was advanced to the distal LAD and repeat OCT revealed that the scaffold had now, fortuitously, been pushed down into the proximal-mid LAD, likely by the advancement of the OCT catheter (B, C).

The two twisted wires were then withdrawn; unfortunately, the scaffold was not removed. This also meant the scaffold was now no longer mounted on a wire.

For additional reading, please consult total stent loss with guidewire in situ

Snaring technique

Next, a snare (*) was advanced to the dislodged scaffold and deployed (A, B). On pulling back, there was significant resistance within the artery.

When the snare was removed, small fragments of BRS were seen (C, D). OCT confirmed the rest of the BRS remained in the LAD (E).

For additional reading, please consult total stent loss with guidewire in situ

Stent implantation and final angiogram

Finally, it was decided to crush the undeployed Mg-BRS with a 3.0 x 40mm DES.

The DES was positioned to cover the proximal-mid LAD as initially planned.

The DES was positioned to cover the proximal-mid LAD as initially planned.

Final angiographic appearances were satisfactory.

Final OCT

Final OCT showed a well expanded DES with a “crushed” Mg-BRS between the DES and the vessel wall.