The treatment of most diseases of the systemic vascular system is undergoing a shift from massively invasive to minimally invasive and from traditional surgery to endoluminal treatment. Endoluminal vascular surgery techniques for the treatment of large arterial lesions have the advantages of less trauma, faster postoperative recovery, and fewer complications, and endoluminal treatment should be given priority when available, especially for patients who cannot tolerate surgery.
The most widely used traditional staging methods for aortic coarctation are the Stanford staging and the DeBakey staging, and Daily et al. of Stanford University classified thoracic aortic coarctation aneurysms into two types: those involving the ascending aorta, regardless of the origin of the coarctation, are referred to as type A; those originating in the descending thoracic aorta and not involving the ascending aorta are referred to as type B. Currently, Stanford’s staging is more commonly used.
Grading of aortic coarctation
Grade 1 refers to typical aortic coarctation with a ruptured and avulsed intimal sheet dividing the aorta into true and false chambers; grade 2 refers to aortic intima-media degeneration with subintimal hematoma formation or subintimal hemorrhage; grade 3 refers to small eccentric aortic wall swelling confined to the vicinity of the intimal rupture; grade 4 refers to aortic wall ulceration formed by ruptured aortic appendage plaque; grade 5 refers to medical or traumatic aortic coarctation.
Staging of aortic coarctation
The chronic stage is defined as asymptomatic aortic coarctation found after 14 days of acute disease or incidentally during physical examination.
We often encounter different problems and phenomena during endoluminal procedures, and the management of the more common problems we encounter is described below.
If the aortic coarctation involves the LSA or if the coarctation endothelial rupture is too close to the LSA opening and the overlying stent anchorage area is too short, the “chimney” technique can be used to restore the LSA blood supply. Especially for patients with left-sided vertebral artery dominance, if the main stent covers the LSA intraoperatively, the blood supply to the left-sided vertebral artery will be affected, resulting in left-sided cerebral ischemia. For thoracic aortic coarctation aneurysms involving the LCCA, reconstruction of the LCCA using the “chimney” technique can restore the blood supply to the LCCA, but the main stent also covers the LSA, which may increase the risk of theft syndrome after surgery. For thoracic aortic coarctation involving the innominate artery (IA), intracavitary isolation using the “chimney” technique for IA covers both the LCCA and LSA openings, and the combined application of cervical-thoracic hybridization is an option to reconstruct the LCCA and LSA flow. Thoracic hybridization.
Management of aortic coarctation fissures
Most aortic coarctations have more than one rupture. The first rupture is often in the aortic isthmus, which serves as the inflow of the coarcted false lumen and continues down to the abdominal arterial rupture to form a second, third or even more ruptures, which serve as the outlet of the false lumen flow. When the pseudoluminal outlet involves the visceral artery, it is difficult to completely thrombose the pseudoluminal cavity by simple endoluminal isolation at the first rupture, and the continuous impact of the blood flow from the visceral artery rupture will easily lead to the aggravation of the visceral artery entrapment and the symptoms of visceral artery ischemia, at this time, it is recommended to perform endoluminal isolation by using a laminated stent for the visceral artery rupture, and if intraoperative regurgitation of the distal rupture is seen, balloon dilation, distal graft sealing and coagulation promotion can be used If intraoperative regurgitation of the distal fissure is seen, balloon dilation, distal graft blocking and procoagulation can be used. For example, Professor Jing Zaiping of Shanghai Changhai Hospital has made a homemade “saltire-like” stent-artificial vascular composite graft to close the renal artery fissure, which can play a very good effect.
Treatment of pseudoluminal blood supply to the visceral artery
There are still differences in the procedures and methods for the endoluminal treatment of aortic coarctation in which the visceral artery is involved and supplied by a false lumen. In general, intracavitary treatment of cases with preoperative determination of true lumen, true or false lumen supply, or impaired power type will improve the blood supply to the visceral artery, and there are studies both in China and abroad to support this view. If the anatomy, nature and hemodynamic changes of visceral artery ischemia are accurately understood, postoperative changes in the blood supply to the visceral artery can be anticipated,
The need for simultaneous or second-stage surgical management can be determined. In cases where the preoperative supply is not clear, or where there is a complete pseudoluminal supply or no supply, or in cases of hydrostatic damage, the postoperative changes in the blood flow of the visceral artery are more uncertain and the surgical approach is controversial. In addition, if surgical treatment is required, there is no unanimous opinion on the choice of open window, stenting (both bare and with membrane stents) or conventional surgery.
Management of combined distal ischemia Thoracic aortic coarctation aneurysms with limb or organ ischemia have a high misdiagnosis rate because patients often present with symptoms such as acute abdomen, acute lower limb ischemia, shock, and paraplegia. Therefore, patients with a history of hypertension,
Therefore, the diagnosis of thoracic aortic coarctation aneurysm should be considered in cases of acute lower extremity ischemia secondary to retrosternal or low back pain. Some scholars believe that Stanford type B thoracic main coarctation combined with branch vessel obstruction should be treated with emergency surgery to restore blood supply to the distal lumen of the coarctation, and some scholars have reported the treatment of coarctation combined with acute organ or limb ischemia by coarctation septal windowing, which is considered to be effective in most cases of kidney or lower limb ischemia caused by coarctation. It is also believed that thoracic aortic coarctation aneurysms with acute lower extremity ischemia should not be operated urgently, but should be treated by relatively small extra-anatomical bypasses such as femoral-femoral bypass and axillary-femoral bypass to improve blood supply and save the limb after the acute phase.
Prevention of intraoperative paraplegia with endoluminal treatment
Paraplegia is a catastrophic and unpredictable complication after surgical treatment of thoracic aortic dissecting aneurysms (TAD). The causes of spinal cord injury after endoluminal treatment are not fully understood, but are thought to be related to isolation of the main blood supply arteries to the spinal cord, low perfusion pressure in the spinal arteries, ischemia-reperfusion injury, and the metabolic rate of the spinal cord. Since the endothelial rupture in most patients is located 1~3 cm below the opening of the left subclavian artery in the descending aorta, i.e., at the height of T 3 and T4, and the intercostal arteries, which are important for spinal blood supply, are usually located between T 8 and L3, the placement of grafts at the height of T3 and T4 does not close the important blood supplying intercostal arteries of the spinal cord. In China, it has been reported that it is safer to use a graft with a length of 8-10 cm to be released at the height of T3 to T5, which can achieve complete isolation of the rupture and maximize the protection of the spinal cord blood supply. Cerebrospinal fluid drainage (CSFD) can significantly reduce the spinal cord perfusion pressure (SCPP) and maintain a good spinal cord blood supply. Continuing CSFD after surgery can prevent paraplegia or mild paralysis due to ischemia-reperfusion injury and spinal cord edema.
Prevention of endoleaks
Endoleak is a special complication associated with endoluminal treatment that differs from open vascular surgery in that the graft does not completely isolate the lesion, and thus blood flow can still enter the lesion. After endoleaks occur, the hemodynamic stability is disturbed, the direction and velocity of blood flow are altered, and the compression of the vessel wall by the graft causes local edema and inflammatory changes, increasing the fragility of the vessel wall and the risk of aneurysm or clamping rupture. Therefore, endoleaks are a very important complication of endoluminal therapy. We classify the endoleaks after endoluminal treatment of TAD into type IV. Type I refers to proximal endoleaks, including poor apposition, fissure extension, or creation of new fissures. Type II refers to reflux, including reflux from the gap between the distal end of the graft and the wall, reflux from the distal fissure, and reflux from the branch artery. Type III refers to endoleaks associated with graft disruption or connection, including stent disruption, ruptured artificial vessels, and pinholes. Type IV endoleaks are those with poor graft sealing performance, resulting in extensive leakage. For type I endoleaks, the blood flow into the prosthetic cavity is often high in velocity and pressure,
Theoretically, it has a greater impact on the hemodynamics of the prosthetic cavity and is more likely to cause postoperative rupture, and should be treated as soon as possible. For type II endoleaks, if the endoleak is caused by a poorly attached graft, it can be propped up by balloon expansion; a bare stent without an artificial vessel can also be used to achieve permanent propping. For type III endoleaks, whether the stent is damaged, the artificial vessel is ruptured, or the needle hole in the graft is leaking, the endoleak can be corrected or the breach closed by reinserting another tubular stent-artificial vessel composite graft into the lumen. For type IV endoleaks, procoagulation may be attempted, but if this is not successful, conventional surgery should be intermediate at a later date under close observation.
Intraluminal repair with a laminated stent can reduce the complication rate and mortality in the treatment of type B aortic coarctation. Choosing the appropriate timing of surgery, careful intraoperative operation, selecting the appropriate stent, and reasonable management of common problems during surgery can reduce the occurrence of postoperative complications, while long-term postoperative imaging follow-up is essential for the prevention and treatment of complications.