Author + information
- Gaoke Feng1,
- Jianmin Xiao2,
- Chaoshi Qin1,
- Zhao Lu1,
- Jun Li1,
- Xiaoxin Zheng1,
- Shuzhong Liu3,
- Tim Wu4 and
- Xuejun Jiang1
- 1Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China
- 2Department of Cardiology, the Affiliated Hospital of Medical College of Jinan University, the Fifth People's Hospital of Dongguan, Guangdong
- 3Renmin Hospital of Wuhan University, Wuhan, PR China
- 4VasoTech, Inc., Lowell, MA
Our previous studies had confirmed the superior biocompatibility and radial strength of the bioresorbable poly-L-lactic acid/amorphous calcium phosphate (PLLA/ACP) scaffolds compared to PLLA scaffolds. The purpose of this study was to conduct further dynamic observations on the performance of the novel fully bioresorbable PLLA/ACP scaffolds (NFBS) after 24-month implantation in porcine coronary arteries compared with the drug-eluting stents (DES).
Twenty-five NFBS (3.0×13.0 mm) and 25 DES (3.0×16.0 mm) were implanted in the coronary arteries of 25 miniature pigs. The scaffold performance was continuously observed through coronary angiography and intravascular ultrasound (IVUS) for 24 months. Quantitative coronary angiography (QCA) was used to measure and calculate the reference vessel diameter (RVD), mean lumen diameter (MLD) and late lumen gain (LLG). Quantitative IVUS software (QIVUS) was applied for the measurements of reference vessel area (RVA), mean stent area (MSA), mean lumen area (MLA) and luminal patency rate (LPR). Scanning electron microscope (SEM) was used to observe re-endothelization degree and scaffold structure. Stereoscope was used to observe the degradation shape and outline of the scaffold strut.
At 24-month follow-up, QCA showed that the RVD [(3.63±0.21) mm vs. (3.21±0.25mm), p<0.05], the MLD [(3.39±0.27) mm vs. (2.78±0.33) mm, p<0.05], and the LLG [(0.47±0.13) mm vs. (0.06±0.26) mm, p<0.01)] in the NFBS-treated vessels were all greater than those in the DES-treated vessels. For IVUS parameters, RVA [(9.31±0.54) mm2 vs. (8.18±0.56) mm2, p<0.05], MSA [(8.99±0.62) mm2 vs. (6.59±0.62) mm2, p<0.05], and MLA [(8.59±0.81) mm2 vs. (5.95±0.77) mm2, p<0.01] were also improved in the NFBS-treated vessels. During the 24-month follow-up, the LPR of the NFBS-treated vessels was significantly increased from (74.31±6.23) % to (92.1±4.59) %. As to the DES-treated vessels, it decreased from (86.81±5.92) % to (72.85±9.80) % in a descending manner. SEM indicated that the surface of NFBS developed a tight arrangement of endothelial cells with complete coverage in 6 months. Stereoscopic observations revealed the stent struts could retain a clear shape in 1 month; and reduce uneven thickness with indistinct edges and progressed corrosion-like changes in 12 months.
The lumen of PLLA/ACP scaffold increased with the growth of reference vessel in 24 months. Late positive remodeling and late lumen gain can be archived in NFBS-treated vessels, which contributes to vascular restoration due to scaffold degradation and unattainable in the DES-caged segments. These benefits demonstrated preclinically may translate into improvements in long-term clinical outcomes for patients treated with NFBS compared with DES.