Early Results of the Newly-Designed Flowdynamics Dense Mesh Stent for Residual Dissection After Proximal Repair of Stanford Type A or Type B Aortic Dissection: A Preliminary Single-Center Report From a Multicenter, Prospective, and Randomized Study.

Background: Negative remodeling of the distal aorta due to residual dissection significantly impacts the long-term outcomes of dissection patients after proximal repair of acute aortic dissection. Branched/fenestrated aortic stents are technically demanding, and studies of the first generation of multilayer flow modulators for tackling this clinical scenario are few and limited. The single-center results from a multicenter, prospective, and randomized controlled study aimed to verify the safety and effectiveness of a newly-designed flowdynamics dense mesh stent for treating residual dissection after proximal repair.

Methods: Patients with nonchronic residual dissection involving visceral branches were prospectively enrolled in 3 centers (ChiCTR1900023638). Eligible patients were randomly assigned to the flowdynamics dense mesh stent (FDMS) group and control group. Follow-up visits were arranged at 1, 3, 6, and 12 months after recruitment. The primary endpoints were all-cause and aortic-related mortality. The secondary endpoints included visceral branch occlusion, reintervention, and severe adverse events. Morphological changes were analyzed to exhibit the therapeutic effect. Our center participated in the multicenter prospective randomized controlled trial, and the preliminary single-center experience was reported.

Results: Thirty-six patients were enrolled in our center, and the baseline characteristics of the 2 groups were comparable. Thirty-four patients completed the 12 month follow-up. Freedom from all-cause and aortic-related death were 94.4% and 100%. All visceral branches remained patent in the FDMS group. Increased area of the true lumen (1.03±0.38 vs 0.48±0.63 cm² at the plane below renal arteries, p=0.006; 1.27±0.80 vs 0.32±0.50 cm² at the plane 5 cm below renal arteries, p<0.001) and decreased area of the false lumen at the plane below renal arteries (-1.03±0.84 vs -0.15±1.21 cm², p=0.023) were observed in the FDMS group compared with those parameters in the control group. The FDMS group showed a significant increase in true lumen volume (p<0.001) and a significant decrease in false lumen volume (p=0.018).

Conclusions: This newly-designed FDMS for endovascular repair of residual dissection after the proximal repair is safe and effective at 12 months.

Clinical impact: One-year results of the randomized controlled clinical trial indicated the short-term safety and promising effect of FDMS on treating non-chronic residual dissection after proximal repair. At the 12th-month follow-up, the true lumen expanded, the false lumen shrunk and all visceral arteries kept patent. As far as I'm concerned, this is the first randomized controlled study concerning utilizing multilayer flow mesh stent treating aortic dissection. Despite a preliminary single-center report, our results are supposed to provide high-quality evidence to guide clinical practice and fill the gap in the application of FDMS.