Discussion

Stent fracture (SF ) and Psudofracture (LSD) are associated with increased risk of TLR ( ISR and stent thrombosis)

Risk factors for SF Include

• Stent type /procedural related (Stent type ie,sirolimus stent , Long stent, Overlapping stent, Excessive pressure during stent deployment)
• Lesion related ( RCA stenting , Calcification, ostial and bifurcation)
• Patient related factors such as hypertension and chronic kidney disease

Longitudinal Stent Deformation (LSD) is a procedural complication occurs with post dilation with non-compliant balloon, a guide catheter or a device such as an intravascular ultrasound catheter

• Some stent designs have a connection to LSD.
• Stent performance is affected by a number of factors, including the flexibility of the crimped and deployed stents, their trackability, scaffolding, radio-opacity, longitudinal and radial strengths, and their recoil.
• The improvement of one stent feature may, however, have a negative impact on other stent attributes.
• In order to maximize flexibility and side-branch access, for instance, fewer connectors were used between the hoops, which decreased longitudinal strength and increased the risk of longitudinal distortion.
• LSD can be caused by the most popular stent platform:

1. Platform Element (Boston Scientific, Natick, Massachusetts, USA)

2.(Medtronic Inc., Minneapolis, Minnesota, USA) driver platform

3.The United States’ XIENCE V (Abbott Vascular, Santa Clara, CA)

Mechanism of LSD and associated risk 

• An angioplasty balloon or guide catheter exerts pressure to a specific location on the proximal circumference of the stent (most frequently the proximal ends, but it can also happen at the body or distal end), especially when the catheter is not coaxial with the stent.
• It results in stent hoops being pushed together, deformation of the proximal end of the stent, lumen obstruction, and stent malapposition.
• The appearance has been compared to that of a concertina or accordion, with the struts compressed, squeezed, or pushed together, or with stent shrinking, folding, or wrinkling

Mechanism of LSD and associated risk 

• In addition to luminal obstruction , longitudinally deformed stents have been linked to an increased risk of:

➢In stent thrombosis

➢Instent restenosis  (malapposition results in Inconsistent drug distribution )

➢Uncovered segment require additional stenting or revascularization surgery

Discussion

• Looking back, we found that the stent used was a Promus stent.
• In our case we additionally deployed a Resolute Onyx stent with good angiographic and IVUS results

Conclusion

• The likelihood of Target Vessel Revascularization (TVR) is increased by both stent fracture (SF) and pseudofracture (LSD).
• Strong grounds for suspecting LSD when passing equipment (such as a balloon) is difficult.
• LSD Additional stenting is necessary for the uncovered segment
• To choose the right stent and achieve the best results, the operator and CATHLAB team should be knowledgeable about the kind and qualities of stents.