Intracoronary Optical Coherence Tomography and Histology at 1 Month and 2, 3, and 4 Years After Implantation of Everolimus-Eluting Bioresorbable Vascular Scaffolds in a Porcine Coronary Artery Model: An Attempt to Decipher the Human Optical Coherence Tomography Images in the ABSORB Trial

• Published in: Circulation (New York, N.Y.) N.Y.), 2010-11, Vol.122 (22), p.2288-2300
• Main Authors: ONUMA, Yoshinobu, SERRUYS, Patrick W, VAN BEUSEKOM, Heleen, VAN DER GIESSEN, Willem, VIRMANI, Renu, PERKINS, Laura E. L, OKAMURA, Takayuki, GONZALO, Nieves, GARCIA-GARCIA, Hector M, REGAR, Evelyn, KAMBERI, Marika, POWERS, Jennifer C, RAPOZA, Richard
• Format: Article
• Language: English
• Subjects: Absorbable Implants; Animals; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Coronary heart disease; Coronary Vessels - pathology; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Drug-Eluting Stents; Everolimus; Heart; Humans; Medical sciences; Models, Animal; Polymers; Proteoglycans; Retrospective Studies; Sirolimus - analogs & derivatives; Swine; Swine, Miniature; Time Factors; Tissue Scaffolds; Tomography, Optical Coherence - methods
• ISSN: 0009-7322; 1524-4539; 1524-4539
• DOI: 10.1161/CIRCULATIONAHA.109.921528

With the use of optical coherence tomography (OCT), alterations of the reflectance characteristics of everolimus-eluting bioresorbable vascular scaffold (BVS) struts have been reported in humans. In the absence of histology, the interpretation of the appearances of the struts by OCT remains speculative. We therefore report OCT findings with corresponding histology in the porcine coronary artery model immediately after and at 28 days and 2, 3, and 4 years after BVS implantation. Thirty-five polymeric BVS (3.0×12.0 mm) were singly implanted in the main coronary arteries of 17 pigs that underwent OCT and were then euthanized immediately (n=2), at 28 days (n=2), at 2 years (n=3), at 3 years (n=5), or at 4 years (n=5) after implantation. All BVS-implanted arteries in these animals were evaluated by histology except for 5 arteries examined at 2 years with gel permeation chromatography to assess the biodegradation of the polymeric device. Fourteen arteries with BVS from an additional 6 pigs were examined by gel permeation chromatography at 1 (n=1), 1.5 (n=2), and 3 (n=2) years. Corresponding OCT and histology images were selected with the distal and proximal radiopaque markers used as landmarks. At 28 days, by OCT, 82% of struts showed sharply defined, bright reflection borders, best described as a box-shaped appearance. Histologically, all struts appeared intact with no evidence of resorption. At 2 years, by OCT, 60±20 struts were discernible per BVS with 80.4% of the strut sites as a box-shaped appearance. Despite their defined appearance by OCT, by histology, these structures appeared to be composed of proteoglycan, with polymeric material being at such low level as to be no longer quantifiable by chromatography. At 3 years, by OCT, recognizable struts decreased to 28±9 struts per BVS: 43.7% showed dissolved black box; 34.8%, dissolved bright box; 16.1%, open box; and 5.4%, preserved box appearance. Histology shows that connective tissue cells within a proteoglycan-rich matrix replaced the areas previously occupied by the polymeric struts and coalesced into the arterial wall. At 4 years, by OCT, 10±6 struts were recognizable as either dissolved black or dissolved bright box. In histology, these struts are minimally discernible as foci of low-cellular-density connective tissue. Relative to the prediction of histological type by OCT appearance, the preserved box appearance of OCT corresponds well with 2-year histology (86.4%), whereas the dissolved bright and bl