Evaluation of intracoronary stenting by intravascular optical coherence tomography

Abstract

Background: Conventional contrast cineangiography and intravascular ultrasound (IVUS) provide a limited definition of vessel microstructure and are unable to evaluate dissection, tissue prolapse, and stent apposition on a size scale less than 100 micro m.

Objective: To evaluate the use of intravascular optical coherence tomography (OCT) to assess the coronary arteries in patients undergoing coronary stenting.

Methods: OCT was employed in patients having percutaneous coronary interventions. Images were obtained before initial balloon dilatation and following stent deployment, and were evaluated for vessel dissection, tissue prolapse, stent apposition, and stent asymmetry. IVUS images were obtained before OCT, using an automatic pull back device.

Results: 42 stents were imaged in 39 patients without complications. Dissection, prolapse, and incomplete stent apposition were observed more often with OCT than with IVUS. Vessel dissection was identified in eight stents by OCT and two by IVUS. Tissue prolapse was identified in 29 stents by OCT and 12 by IVUS; the extent of the prolapse (mean (SD)) was 242 (156) microm by OCT and 400 (100) microm by IVUS. Incomplete stent apposition was observed in seven stents by OCT and three by IVUS. Irregular strut separation was identified in 18 stents by both OCT and IVUS.

Conclusions: Intracoronary OCT for monitoring stent deployment is feasible and provides superior contrast and resolution of arterial pathology than IVUS.

Figure 1

Summary of observations with optical coherence tomography (OCT) and intravascular ultrasound (IVUS): 42 stents were imaged in 39 subjects.

Figure 2

Dissection observed with optical coherence tomography (OCT) (A) and intravascular ultrasound (IVUS) (B) following balloon dilatation. Although the tissue flap can be seen in the IVUS image, it is difficult to determine the depth of dissection. In the OCT image, the bright-dark-bright banding within the flap suggests involvement of the adventitia. In each image, tick marks represent 1.0 mm, and the guide wire location is denoted by an asterisk. Following stenting, the disrupted tissue was held in place and a patent lumen was observed.

Figure 3

(A) Optical coherence tomographic image of a stent showing minor dissection (∼250 μm in depth) between stent struts at 6 o’clock. The individual struts appear as opaque bands at the vessel surface. The guide wire obstructs the view from 8 to 9 o’clock. The characteristic structure of a layered fibrous plaque is evident between the struts from 11 to 3 o’clock. (B) Corresponding intravascular ultrasound image. The guide wire in this image is at ∼8 o’clock. A minor dissection is evident at 6 o’clock.

Figure 4

(A) Optical coherence tomographic image showing tissue prolapse (filled arrow at 7 o’clock, measuring 340 μm). At 2 o’clock (open arrows) the stent is under deployed by 100 μm. Neither of these small features is readily apparent in the corresponding intravascular ultrasound image (B).

Figure 5

Stent having irregular spacing between adjacent struts acquired with optical coherence tomography (A) and with intravascular ultrasound (B). At locations of greater strut separation, the pronounced angulation observed in the vessel wall (arrow in A) may correspond to increased focal stress.

Figure 6

Optical coherence tomography (OCT) (A) and intravascular ultrasound images (B) of a patient with in-stent restenosis. In the left portion of the OCT image (3 o’clock to 12 o’clock) neointimal growth is seen inside of the stent struts. Two guide wires, denoted by asterisks, were used in this procedure.