Background:
We have previously demonstrated that adventitial inflammation, including enhanced formation of adventitial vasa vasorum (VV), is involved in the pathogenesis of coronary spasm in porcine models and that optical frequency domain imaging (OFDI) allows us to visualize adventitial VV in humans in vivo. However, it remains to be elucidated whether adventitial VV is also involved in the coronary hyperconstriction in patients with vasospastic angina (VSA). In this study, we thus examined the extent of VV formation in VSA patients and control subjects by using OFDI.
Methods:
OFDI image acquisition of the left anterior descending coronary artery (LAD) was performed along the LAD at every 10 mm length after intracoronary administration of isosorbide dinitrate in 21 patients with acetylcholine-induced spasm and 10 control subjects without the spasm.
Results:
Patient characteristics were comparable between VSA patients and control subjects, including sex, age, cardiovascular risks and medications. OFDI and reconstructed 3D-OFDI images clearly visualized enhanced VV formation in VSA patients as compared with control subjects (Figure). Quantitative analysis showed that VV area was significantly larger in VSA patients than in control subjects (VSA, 0.093±0.006 vs. control, 0.040±0.006 mm
2
, P<0.0001), whereas vessel diameter, wall thickness and coronary lesion types were all comparable between the 2 groups.
Conclusions:
These results demonstrate for the first time that adventitial VV formation is enhanced at the spastic coronary segment in VSA patients, suggesting the important role of adventitial VV in the pathogenesis of coronary spasm.
High frame-rate intravascular optical frequency-domain imaging in vivo
