A cannula connecting strategy fostering vascular anastomosis based on mechanical support and biochemical modulation

Anastomosis is essential in cardiovascular surgery. However, traditional hand-sewn techniques are technically demanding, and existing sutureless methods often result in complications such as thrombosis and delayed healing due to poor mechanical compliance and insufficient endothelialization. Herein, we propose a cannula connection strategy that combines mechanical and biochemical support via a vascular-shaped polyetheretherketone (PEEK) connector. The PEEK substrate is coated with polydopamine (PDA) and chemically grafted with S-nitroso-N-acetylpenicillamine (SNAP) to enable sustained nitric oxide (NO) release. This approach significantly enhances anastomotic mechanical performance by improving tensile strength and burst pressure, thereby holding promise for reducing operation time and minimizing blood leakage. Compared to non-grafted SNAP coatings (PP-S), the chemically grafted version (PP@S) maintains elevated NO release for over 30 days, effectively modulating the local microenvironment, inhibiting platelet adhesion, and promoting the proliferation and spreading of human umbilical vein endothelial cells (HUVECs). In vivo studies show that the cannula device shortens surgical time by approximately 50 % and significantly decreases intraoperative bleeding. The mechanical structure offers resistance to pressure fluctuations, provides spatial reinforcement, and prevents anastomotic leakage. Concurrently, the biochemical modulation minimizes inflammatory responses and systemic toxicity, facilitating collagen fiber formation and further enhancing structural support. This positive feedback loop results in a 99.04 % anastomotic patency rate two months post-surgery. Overall, this integrated cannula strategy provides an alternative to traditional anastomosis techniques by combining mechanical and biochemical support to enhance anastomotic integrity and facilitate healing.