The natural history of Stanford (Stanford) type B aortic coarctation differs from that of type A aortic coarctation in that its prognosis is relatively good, with a lower likelihood of acute aortic dissection, pericardial tamponade, and other emergencies. However, type B aortic coarctation is associated with an older age and patients tend to have a combination of hypertension, atherosclerosis, and diabetes, so its in-hospital mortality rate is not low. An international survey of acute aortic coarctation (IRAD) showed that the in-hospital mortality rate for patients with acute type B coarctation was about 12.8%.
The current Stanford clamping staging method, the DeBakey staging method, and the Crawford staging method for descending aortic coarctation and aneurysmal lesions all have shortcomings and are relatively crude. It is necessary to revisit the Stanford B type entrapment with new concepts and new eyes. Based on many years of treatment experience, and taking into account recent therapeutic advances, the author
Breakdown of treatment strategies for Stanford B entrapment
With an early mortality rate of approximately 32.1% for surgical treatment of Stanford type B entrapment and an early mortality rate of approximately 9.6% for conservative medical treatment, there has been a longstanding preference for conservative medical treatment of type B aortic entrapment. However, the long-term outcome of conservative medical treatment is less satisfactory. Eleftheriaz et al. reported that approximately 9% of patients with acute type B coarctation died during hospitalization, and 66% of the remaining patients required surgical treatment later.
Chronic type B aortic coarctation can occur not only in patients with type B coarctation but also secondary to previous surgical treatment for type A coarctation; therefore, most chronic type B coarctations regress to aneurysm. Even with strict drug treatment, 30-40% of patients will still develop aneurysmal dilatation within 10 years. One study (50 patients, observed for 40 months) showed that approximately 18% of patients died from entrapment rupture during the observation period, and an additional 20% of patients underwent surgery for symptomatic entrapment neoplasia.
By refining the staging of Stanford B entrapment, more appropriate treatment options can be selected for different types of patients.
Interventional treatment
Laminated stent placement is only indicated for patients with B1S aortic coarctation
Since 1994, when Dake et al. pioneered the use of overmolded stents in the treatment of thoracic aortic aneurysms and descending aortic coarctation, there has been no large randomized controlled clinical trial to confirm the long-term results of overmolded stent placement versus conservative treatment, but there is a growing trend toward the aggressive treatment of type B coarctation.
Giovanni et al. reported a high rate of pseudoluminal thrombosis and a low rate of neoplasia (3.5% versus 28.5%, P=0.02) in cases of acute type B entrapment treated with intervention. According to recent data, interventional treatment may have better results than conservative treatment alone and surgical treatment, but the key is to strictly grasp the indications for treatment.
In clinical work, the author also encountered more patients who required surgical treatment due to poor selection of surgical indications, resulting in proximal aortic coarctation after stent placement. Therefore, the author believes that overlapping stent placement is only suitable for patients with B1S type aortic coarctation.
Aggressive surgical treatment
Patients with type B2, B3, and C aortic coarctation (not suitable for overmolded stent placement) should receive surgical treatment.
Type B1C coarctation can be treated with partial thoracic descending aortic replacement or partial thoracic descending aortic replacement + distal stent placement for these cases. For some patients, a left subclavian artery can be bypassed with the ascending aorta by placing a self-expanding stent vessel through the left common carotid artery and the left subclavian artery using a median opening.
Type B2 entrapment partial thoracic descending aorta + distal angioplasty is indicated for patients with chronic entrapment. If the patient has poor vessel wall quality, total thoracic aortic replacement should be performed.
Type B3 entrapment should be performed as a total thoracoabdominal aortic replacement for these cases. This procedure is difficult and requires a high level of operator and extracorporeal circulation, so it should be performed in an experienced cardiovascular center.
Hybrid technique
Currently, some advanced centers abroad are trying Debranch (debranching, note: head and arm artery reconstruction) + distal stent placement in some patients with type B coarctation. And the results show that this hybrid treatment has good recent efficacy in patients with more complex lesions.
Insights and explorations
1, The refined staging of Stanford type B entrapment helps to select the correct treatment plan, improve the treatment outcome and reduce the reoperation rate.
2.After the diagnosis of type B aortic coarctation is confirmed, it should still be treated with more aggressive interventions.
3.There is still a big controversy about the timing and indications for treatment of B-type aortic coarctation. We hope that domestic units that are qualified to treat aortic coarctation can cooperate and conduct multicenter randomized controlled clinical studies. And we believe that with the progress of materials, science and related technology, the diagnosis and treatment level of aortic coarctation will be greatly improved.