Endovascular optical coherence tomography ex vivo: venous wall anatomy and tissue alterations after endovenous therapy

Endovascular optical coherence tomography (OCT) is a new imaging modality providing histology-like information of the venous wall. Radiofrequency ablation (RFA) and laser therapy (ELT) are accepted alternatives to surgery. This study evaluated OCT for qualitative assessment of venous wall anatomy and tissue alterations after RFA and ELT in bovine venous specimens. One hundred and thirty-four venous segments were obtained from ten ex-vivo bovine hind limbs. OCT signal characteristics for different wall layers were assessed in 180/216 (83%) quadrants from 54 normal venous cross-sections. Kappa statistics (kappa) were used to calculate intra- and inter-observer agreement. Qualitative changes after RFA (VNUS-Closure) and ELT (diode laser 980 nm, energy densities 15 Joules (J)/cm, 25 J/cm, 35 J/cm) were described in 80 venous cross-sections. Normal veins were characterized by a three-layered appearance. After RFA, loss of three-layered appearance and wall thickening at OCT corresponded with circular destruction of tissue structures at histology. Wall defects after ELT ranged from non-transmural punctiform damage to complete perforation, depending on the energy density applied. Intra- and inter-observer agreement for reading OCT images was very high (0.90 and 0.88, respectively). OCT allows for reproducible evaluation of normal venous wall and alterations after endovenous therapy. OCT could prove to be valuable for optimizing endovenous therapy in vivo.