[Evaluation of neointimal proliferation in stented canine coronary artery with optical coherence tomography]

To evaluate the accuracy of optical coherence tomography (OCT) in evaluating neointimal proliferation in canine coronary artery following stenting.

In 15 domestic dogs, a single bare-metal stent was implanted in the anterior descending or the circumflex branch of the left coronary artery. Ninety days after stenting, the dogs underwent coronary angiography and OCT, followed by quantitative histological assessment of neointimal proliferation in the target arterial segments. The parameters of OCT and the histological findings were analyzed comparatively.

A total of 15 OCT-histology matched frames acquired at the point with the most severe stenosis in every stent, and 60 pathological sections from all the stents were analyzed. The difference of the stent area assessed by OCT was comparable to that defined histologically (5.01∓0.79 mm(2) vs 4.99∓0.81 mm(2), P>0.05). Neointimal thickness and area were smaller with OCT assessment than with histological assessment (0.19∓0.08 mm vs 0.22∓0.10 mm, and 1.52∓0.49 mm(2) vs 1.85∓0.78 mm(2), respectively, P<0.05). The lumen area was larger by OCT assessment than by histological assessment (3.50∓0.66 mm(2) vs 3.15 ∓ 0.43 mm(2), P<0.05). Close correlations were found between OCT and histological evaluations of the neointimal thickness (R(2)=0.5280.767), neointimal area (R(2)=0.5280.537) and stent area (R(2)=0.528), but the correlation was poor for lumen area (R(2)=0.5280.307). All the stents showed full endothelialization without thrombus or aneurysm in the stents.

OCT allows precise and reproducible assessment of neointimal proliferation in the coronary artery following stenting, but for measurement of the lumen area, OCT shows a poor correlation to histological evaluation.