The following reasons need the removal of a lead:

• Infection at the device or lead's location.
• Damage to the lead on the inside or outside.
• Scar tissue is developed at the lead's tip.
  
• A clot or scar tissue can block a vein.
  

Reference - Lead Extraction. (n.d.). Retrieved from https://my.clevelandclinic.org/health/treatments/17165-lead-extraction