Aortic debranching from the ascending aorta: a novel surgical approach for extended TAAA and chronic type B dissections in high risk patients.

AIM: Extend thoraco-abdominal aortic aneurysms (TAAA) involving arch vessels and the visceral arteries remains a challenging operation when affecting high risk patients (HRP). Recently, hybrid surgery has gained popularity for HRP. The conventional surgical repair is the gold standard for low risk patients with previous mortality from 6% to 15% in thoracic aneurysms up to 30% in thoracic type B dissections. The risk of paraplegia is 3% to 15%. Without repair the outcome is poor with only 35% of patient's survival at two years after diagnosis. The total endovascular technique is not widespread used because of its very time-consuming, needs training, and procedure planning with high radiation exposure. Only few centers in the world perform it. In order to reduce the morbidity a novel approach is proposed, with an aortic debranching from the ascending aorta. METHODS: Nine patients (two females) aged between 53 and 81 years, with high risk factors for surgery, were offered this hybrid technique from March 2004 to July 2009. Eight patients presented with a TAAA and one type a B chronic dissection. A staged hybrid operation started by a debranching of the aorta from a median sternotomy to supra-aortic vessels and visceral arteries, followed by the second stage one-two weeks later, with an extended stent grafting. This attitude avoids CPB and aortic cross clamping. The surgical approach is a median sternotomy combined to mid upper laparotomy associated to pericardial and diaphragm division. It is well tolerated even in elderly patients and allows easy access to celiac axis (CA), superior mesenteric artery (SMA), right renal artery (RRA). Access to the left renal artery is more difficult and may be benefit from a combinated stent grafting and bypass according to the VORTEC technique described by Lachat M, or an extra-anatomic bypass. Rerouting the visceral arteries is done from the ascending aorta with a partial clamping on an undiseased implantation site, offering à good anterograde high flow. Combined bypass to supraaortic vessels is associated when needed. RESULTS: There was no intraoperative mortality. One patient died during 30D period from cardiac failure and another on the early follow up from a pancreatic fistula. The complications: one stroke (11.1%); one cardiac failure (11.1%); one renal failure (11.1%), one pancreatic fistula (11.1%), one non-infected retrostrenal collection (11.1%). No paraplegia, limb ischemia or aortic fistula were detected. No stent-graft related complication was retrieved, the bypass patency was 77.7 at four-year survival. CONCLUSION: Our early and mid term results are promising and similarly to other series. This new approach for rerouting the supraaortic and visceral arteries before stent grafting in extended TAAA, lowers the surgical injury and is particularly designed for HRP who cannot benefit from conventional surgery under CPB. Larger series and longer follow-up are needed.

Retrograde type A aortic dissections after endovascular stent-graft placement for type B dissection.

Thoracic endovascular aortic repair (TEVAR) has emerged as promising and a less invasive alternative to open surgery for high risk patients (HRP) with type B thoracic aortic dissection (TAD). One of the most serious complication of TEVAR is the retrograde type A TAD (rATAD). This review will focus on an interesting rATAD case and will review the literature, regarding the true incidence, mortality, causes, diagnosis, complications and management of rATAD. Until the development of a specific device for TAD, efforts must be made for better patient and device selection, careful and precise instrumentation, and life-long surveillance to minimize this lethal complication.

Percutaneous cervical approach and closing for carotid artery stenting.

The standard route for carotid artery stenting (CAS) is the femoral one, leaving the brachial access as a secondary option. Various anatomic specifications, or occlusions of the routing arteries, make carotid stenting impossible. Percutaneous cervical puncture of the common carotid artery, is a method which can solve access problems. We are presenting the experience from 191 CAS procedures through cervical puncturing and closure of the puncture site in order to prove its safety and efficacy.

Choice of access for percutaneous carotid angioplasty and stenting: a comparative study on cervical and femoral access.

Carotid angioplasty and stenting (CAS) is a well established technique. CAS indications currently still limited are yet evolving. The choice of the access is defined by the risk factors of the patient among whom ''the vascular anatomy'' is essential. The authors will focus here on the accesses, their advantages and their drawbacks. They made a retrospective study relating 314 patients treated by CAS. No significant difference in term of morbidity or mortality between the cervical or femoral access was found but a clear tendency in favor of the cervical access which avoids the arch manipulations. It can be concluded that various access offer better options for CAS and must be discussed depending on the patient's anatomy and risks factors.

Structure of the EF corner favors deamidation of asparaginyl residues in hemoglobin: the example of Hb La Roche-sur-Yon [beta 81 (EF5) Leu----His].

Some abnormal hemoglobins constitute models which allow one to evaluate the structural requirements for post-translational modifications in proteins, such as deamidation. Hb La Roche-sur-Yon [beta 81 (EF5) Leu----His] is an unstable hemoglobin variant displaying a moderately increased oxygen affinity. About half of the abnormal hemoglobin, in addition to the substitution at position beta 81, carries a deamidation of the neighboring asparagine residue, beta 80 (EF4). The histidine at position beta 81 cannot fit into the small hydrophobic pocket which normally accomodates the leucine residue. This structural change opens the heme pocket and modifies the general conformation of the EF segment, thus explaining the increase in oxygen affinity and the achievement of a three-dimensional structure favoring asparagine deamidation. Histidine beta 81 could also act as a catalyst in the deamidation reaction. Deamidation has already been reported for two other variants of the EF corner, Hb Providence [beta 82 (EF6) Lys----Asn] and Hb J Singapore [alpha 79 (EF8) Ala----Gly]. In all these cases it seems that a histidine may catalyze the deamidation of the asparagine residues and that disturbing the folding of the EF corner will provide an extra flexibility favoring the reaction.