“Life’s tragedies are fundamentally arterial,” this is a phrase by William Osler referring to aneurysms and aortic dissections, which remains valid to this day. Aortic dissection is a rare pathology affecting 2-4 patients per 100,000 person-years, with two-thirds being type A, and more frequently affecting males than females. The associated risk factors include hypertension, atherosclerosis, aortic aneurysms, connective tissue diseases, and a history of cardiac surgery. In contrast, a bicuspid aortic valve is a risk factor for aortic aneurysms but not for dissections. Historical cohorts, prior to the 1990s, show a survival of type A aortic dissections managed medically of 43% in the first month and 39% in the first year (Masuda Y et al.). Indeed, the mortality from type A aortic dissections is 1-2% per hour that passes before intervention, which is the benchmark for standard treatment. In the 1990s and 2000s, surgical techniques have been refined with antegrade cerebral perfusion, neuromonitoring, and minimizing, even avoiding, cardiocirculatory arrest. However, despite advances, there remains a portion of the population who are not, and will not be, candidates for surgical treatment due to high surgical risk either from clinical situation, comorbidities, and to a lesser extent, patient’s own will.
Today’s article aims to evaluate the outcomes of patients who were not operated on with type A aortic dissection. For this purpose, they collected data from all dissections operated on at the Ann Arbor Cardiovascular Center, Michigan, from 1996 to 2021. A total of 999 patients came to the center with type A aortic dissection, of which 839 received surgical treatment, 148 were managed with medical treatment and 14 received endovascular treatment. The patients assigned to be medically treated were due to severe comorbidities, organ failure or malperfusion syndrome that increased the surgical risk prohibitively, as well as some cases were by the patient’s will. The data was taken from the STS database and crossed with national and state of Michigan mortality databases, so the patient follow-up was 100%.
Hospital and 30-day mortality in the medically managed cohort was 9 times higher than the surgical cohort (70% vs. 7.9%). The results of this cohort improved over time and when analyzed by decades (1996-2021 vs. 2011-2021), mortality improved (87% vs. 58%; p < 0.001), the risk of aortic rupture decreased (21% vs. 8%; p = 0.008) and 3-year survival improved (13% vs. 29%; p = 0.005). Analyzing the non-surgical cohort more deeply, patients with malperfusion syndrome had similar in-hospital and 30-day survival to those who did not present this syndrome. However, the risk of aortic rupture was four times higher (OR = 4.1; p = 0.03). On the other hand, the intramural hematoma turned out to be a protective factor of mortality (OR = 0.36; p = 0.02).
The authors concluded that surgery in the context of type A aortic dissection remains the standard of treatment. However, alternative treatments such as medical and/or endovascular are a real option in comorbid patients or with malperfusion syndrome, especially in the case of intramural hematoma.
COMMENTARY:
The IRAD registry (International Registry of Acute Aortic Dissections) has reported in a recent study a survival of 62.3% in patients treated medically, data that the present study corroborates. These data are relevant because they allow us to have a cut-off point of surgical risk after which it is better to manage patients medically. Indeed, Centofanti et al. developed a mathematical model to calculate the risk of these patients taking into account age, renal failure, cardiogenic shock, presence of coma, and need for reintervention.
As for medical management, it consists of aggressive blood pressure control aiming to keep systolic pressure below 100 mmHg. Aggressive pain control and absolute rest during the first two weeks are also important. Patients with multi-organ failure or shock will also require pertinent management of complications. Globally, the treatment will be very similar as for a surgical candidate only prolonged. The benefits of this strategy have already been analyzed for intramural hematoma in previous blog entries. Extending it now to more complex forms of presentation of type A aortic syndrome, it is necessary to repeat the imaging test after the first week to determine the dissection situation. At the Ann Arbor cardiovascular center, they were very aggressive with malperfusion syndrome and all non-surgical patients who presented this complication were treated using endovascular procedures. Not without reason, because the risk of aortic rupture in patients with this complication was OR = 4.1. Because of this, mortality in their non-surgical cohort stratified by malperfusion was similar.
Coming to the part of the limitations, we must remember that this article is a single-center retrospective study. The sample size of the cohort studied was small to be able to draw solid conclusions and not fall into type II error. Also, being a center specialized in aortic pathology, the results are hardly extrapolable to our daily practice. Not everywhere is so aggressive in treating malperfusion syndrome.
In conclusion, there is no doubt that surgery is the treatment for type A aortic dissection. However, in certain cases, the patient we are evaluating will not be operable and in such a scenario medical management can provide a solution, if not real, at least pragmatic. As long as, aggressive blood pressure control is maintained, if the patient survives up to 30 days they will probably have overcome the aortic dissection… a benefit that may be greater than what a surgery could offer, which, if performed, might condition that to be their last day of life. Let us remember the old surgical aphorism, “do not operate on a patient on the day of their death.”
REFERENCE:
Ahmad RA, Orelaru F, Titsworth M, Wu X, Kim KM, Fukuhara S, et al. Contemporary nonsurgical management of acute type A aortic dissection: Better outcomes? J Thorac Cardiovasc Surg. 2024 Jun;167(6):2027-2036.e1. doi: 10.1016/j.jtcvs.2022.09.025.
