Total Aortic Arch Replacement With Vascular Ring Connectors in Type A Aortic Dissection

Congratulation, great work!

One may be wondering about the possible hazard of the three INTRAVASCULAR connectors regarding thombogenic process. Has it been proved to be in harmony with the endothelium and thrombocytes? How long is the pts put on any kind of anticoagulation or else?

Updating and old idea A good video showing an interesting technique in a technically successful case and authors have to be commended for it. The concept of intraluminal prostheses is very old and authors have updated it with the introduction of intravascular metal rings. Intraluminal prostheses for the treatment of aneurysms and dissections in different aortic locations were introduced by Lemole et al in 1979 and his group published about 12 papers on this topic, the technique and results in different pathologies until 1998. Some of the references are: Strong MD, Spagna PM, Lemole GM. Sutureless prosthesis for aortic aneurysms. Chest 1979; 75:209. Lemole GM, Strong MD, Spagna PM, Karmilowicz NP. Improved results for dissecting aneurysms. Intraluminal sutureless prosthesis. J Thorac Cardiovasc Surg 1982; 83:249-55. Oz MC, Ashton RC Jr, Singh MK, Serra JS, Lemole GM. Twelve-year experience with intraluminal sutureless ringed graft replacement of the descending thoracic and thoracoabdominal aorta. J Vasc Surg 1990; 11:331-8. Oz MC, Ashton RC Jr, McNicholas KW, Lemole GM. Sutureless ring graft replacement of ascending aorta and aortic arch. Ann Thorac Surg 1990; 50:74-9. Oz MC, Ashton RC Jr, Lemole GM. Aortic replacement with composite grafts created with a sutureless intraluminal ringed prosthesis. J Thorac Cardiovasc Surg 1990; 100:781-6. Oz MC, Ashton RC Jr, Lemole GM. As originally published in 1990: Sutureless ring graft replacement of ascending aorta and aortic arch. Updated in 1998. Ann Thorac Surg 1998; 65:1186-7 It would be good to have follow-up of the case and information on additional cases.

Congratulations, very elegant intervention for a condition that is in some cases a lot of difficulties and pitfalls. My question is in relation to the pressure on the vessel done by ligation. Could create a necrosis with rupture of the vessel tied with a leck of first type? Do you suggest to postop endovascolar cuff placement?

Thanks for your comments. I would like to reply the questions: (1) Fixation of the ring: Sutureless intraluminal graft had been introduced as early as 1979. The original design was a plastic ring covered with a Teflon cloth (the edges of the cloth is thicker so that it looks like there is a furrow). I had been using this product manufactured by USCI and Meadox for many cases in the early years but I found that the rings were easy to dislodge. If we remove the Teflon cloth, we will discover that the ring was lack of furrow and hence easy to displace. This is why false aneurysm may happen and why I decided to make our own ring with furrow for secure fixation. I did weight bearing test on pigs' aorta and found that the Meadox ring can hold only 4 kgs of weight and our titanic ring can hold 15 kgs. (2) Tissue necrosis: I did long term pig experiments and found that the ring was free of thrombosis and false aneurysm 6 months after implantation of the rings in 13 pigs' abdominal aorta. When we took out the rings from the pigs' aorta, we found that there was dense fibrotic tissue covering the rings and the tapes, making it very difficult to remove the ring. I believe that the tapes we used to secure the ring provide a greater area of contact surface than ordinary threads, thus even there is necrosis of the tissue, but the tissue won't disrupt. These data were submitted to FDA and finally get its approval in 2006. (3) Thrombosis: Since there is a small gap between the ring and the graft, I suggest to use warfarin for 6 months before shifting to anti-platelet agents. (4) Lt subclavian artery: I ligated this artery and found that only few cases needed bypass. During surgery, I measure the pressure in Lt subclavian artery, and if its mean pressure is over 50-60 mmHg or it its waveform is pulsatile, I will leave it alone. Since recently I am doing bypass to Lt subclavian artery routinely by using a new technique, i.e. to divide the proximal Lt carotid artery and anastomose it to the Lt subclavian artery, which is easy to do if the Lt sternocleidomastoid muscle is divided. Hopefully I can post the new video in CTSNet soon.

Congratulations for your technique.I have a question regarding the entry point of the dissection. How can be sure that you have exluded it and secondly if you ever had patency problems with the coronary ostia?

Entry tear: I can feel with my finger if there is entry tear in the aortic root. If the tear is in the aortic root, I will enlarge the incision and do David or Bentall operation. In this case, since the entry tear was not in the ascending aorta, the tear would be most likely in the middle arch or distal arch, thus I decided to replace the arch. I don't usually open the whole segment of aortic arch to find the tear. Coronary ostia: Since the tear was not in the aortic root, I would preserve at least 2 cm segment of aortic root for fixation of the vascular ring connector. It is crucial that the ring should be positioned in the aortic root a little higher than the coronary orifices.

Congratulations. I wonder what you do if the patient has aortic valve regurjitation. Do you use retantion sutures? The second question; what do you think about metal ring migration? Thanks

I am sorry for the belated answer: If there is aortic regurgitation, and if the tear is nearby the coronary orifice, I would transect the aortic root and do David or Bentall operation. An if the aortic regurgitation is caused by the dissection flap extension, tying the aortic wall on a ringed Dacron graft will usually reduce the regurgitation. As to migration, we had never had migration and pseudo-aneurysm formation after the use of our vascular ring connectors (VRC). The holding power of this VRC was 15 kgs by ex-vivo pig aorta tests. The old Meadox intraluminal graft could hold 3 kgs of weight since there is not furrow on the ring. If you remove the clothe covering the Meadox ring, you will find the surface of the ring is smooth. This is the reason why they stopped manufacturing their product due to high incidence of migration and pseudoaneurysm formation.

Thanks. This year I met you at Taipei at ASCVTS and enjoyed your presentation. One thing I like to know -how can we collect those vascular rings from Dhaka, Bangladesh. We are also like to hear from you about your follow up data.

I would like to tell you that our long-term results were very exciting and will be published in the future. Until recently, I had done 222 cases of aortic dissection using vascular ring connector (VRC) in the past 8 years, with more than half of the patients received total or hemi-aortic arch replacements. The hospital mortality rate was 4.1%, and late mortality 2.3%. Only one had residual tear at the site of anastomosis. This vascular ring connector (Vasoring®) is manufactured in Taiwan and had been approved by US FDA and Taiwan Health Department. It will be the best if you can provide a trustworthy local agent so that I can help him/her to contact with the manufacturer. My email: jengwei@mac.com