A Primary Study Of Inclined Bifurcation Stent Implantation For Bifurcation Coronary Artery Of Mini-swine

BackgroundBifurcation lesions account for 10-20% in the sufferers of in percutaneous coronary intervention (PCI) , most of which are in the bifurcation of anterior descending branch and diagonal branch. For the distinctive anatomy characteristic of bifurcation, the interventional therapy of bifurcation lesions has been a difficulty and challenge for modern PCI technology. Although the usage of drug-eluting stent (DES) improved the treatment effect of bifurcation lesions, the treatment dilemma of bifurcation lesions haven't been changed by the roots, no matter in the success rate of real-time visualization, the incidence of myocardial infarction in hospital, or in the incidence of restenosis and thrombosis, the PCI of bifurcation lesions are clearly higher than non-bifurcation lesions.Currently, a prevalent treatment for bifurcation lesions is to implant single or double stents according to lesion characteristics of the bifurcation. In order to improve the treatment effect of bifurcation lesions, new technique of stents implantion for bifurcation lesions were invented, most of the techniques among which were difficult to manipulate and hard to be satisfied in whole effect all the time. A high rate of restenosis in the branch still puzzles people. Under these circumstances, some novel dedicated stent for bifurcation were introduced. In recent years, Although the early research on new bifurcation stents was reported in different journals and meetings, most of the bifurcation stents have the uncertain effectiveness, hard manipulation, small adaptation and low success rate. A better treatment method of bifurcation lesions is under discussion and exploration now.ObjectiveTo improve the intervention effect in bifurcation lesions, we designed an inclined bifurcation stent on the basis of anatomy features of bifurcation lesion. Theoretically, A optimal implantion of inclined bifurcation stent can reduce the incidence of stent malapposition, stent overlap and stent "bare area " at bifurcation position, meanwhile the procedure of therapy will also be simplified too. We hope this novel dedicated stent can improve the success rate of treatment of bifurcation lesions and improve the prognosis of bifurcation lesion. The premier objective of this research is to give a judgment of the implantion process of inclined bifurcation stent, and have a first grasp of the positioning performance of inclined bifurcation stent implantion in branch and the effect on restenosis after being implanted, establishing a groundwork for further research.MethodsTotally 19 swine planed to implant inclined bifurcation stent, inclined bifurcation stent were implanted in 17 bifurcation lesions. 6 pigs among which were put to death immediately after being implanted to observe the stent positioning status, and 8 swines (10 bifurcation lesions were treated by inclined bifurcation stent) were fed for a month to observe the incidence of restenosis. During the procedure of stent implantion, the propelling movement performance, dilatability performance, holding power, balloon withdraw performance and the visualization of marker under X rays both before and after stent deployment were scored. Observe the positioning status of inclined bifurcation stent in length and cross direction. Finally give an overall evaluation of stent's positioning performance. Coronary angiography was performed after 1 month in 8 swines to learn the late lumen lose, diameter stenosis, the incidence of restenosis and analyse the the relation between restenosis and stent positioning.ResultsA total of 17 bifurcations were treated with inclined bifurcation stent. Each bifurcation treatment cost 34 minutes on the average, the support power and swelling power of inclined bifurcation stent were all right. The propelling power is a little worse than common stent. The marker on the inclined bifurcation bracket was shown well after stent plolyment and was shown a little worse before stent plolyment. There's a good correlation between the positioning status of inclined bifurcation stent fixed by X ray and shown in dissection. The positioning performance of inclined bifurcation brackets is better in length orientation, the errors in which showed there were five bifurcations≤1.5mm and one bifurcation in 1.5mm, While the positioning performance of cross orientation is tolerable. The bifurcation dissection showed that the positional error of two bifurcations was≤15°, three of them was in 15°-30°, and one in 31°-45°.After a month, the average diameter stenosis of 10 bifurcations is 25.9%, the average late lumen lose is 0.65mm, and the incidence of restenosis is 20%. The occurances of restenosis were possibly correlated with position deviation of stent implantion.ConclusionThe implantion of inclined bifurcation stent has simple procedures, high success rates and a more accurate positioning in branch place. The restenosis rate is low after first observation. This stent is worthy to be researched and developed more.