There has been a significant decrease in mortality from cardiovascular diseases in the past 40 years. For instance, mortality rates in the developed countries from coronary heart disease and stroke declined to about one-third of their 1960s baseline by 2000. 169 While some studies indicate a reasonable decrease in mortality for aortic diseases (both dissections and aneurysms) as well over the past 30 years, the decline is likely not as high as it is for other cardiovascular diseases – precise data for these are not available.
In the past 30 years, there have however been significant advances in treatment procedures for aortic ailments.
While both aortic dissection and aneurysm affect the aorta, each has a different prognosis and recommended management.
Aortic dissections can either be on the ascending aorta, at the arch of the aorta, or the descending aorta. 170 If the dissection is on the ascending aorta, with current medical knowledge, immediate surgery using the open-heart method is the recommended way – without such surgery, the prognosis for such patients is very poor. The goal of surgery is to prevent blood flow into the secondary channel (the false lumen) and to reshape the aorta with a synthetic graft. This was the surgery done for amma post her first aortic dissection in 2011. Such open heart surgeries present their own complications, as the doctors clearly pointed out for amma too, but there isn’t much of an alternative in this case for most people. 171
If the dissection is at the arch and/or the descending portion of the aorta, prognosis and management become a bit more nuanced. For dissections that do not have complications like rupture or lack of blood supply to vital organs, surgery might not be compulsory. In fact, for such cases, conservative management using medications has been shown to provide excellent survival rates even up to 10 years. 172, 173 Such conservative management is optimal for old patients like amma, and this was what was suggested by her doctors too in 2015 after her recurrent dissection. The downside of the conservative management is that the patients could develop complications in the medium term (greater than five years), while those who had undergone surgery could expect a longer period of event-free, complication-free life.
An operation might be recommended for descending aortic dissections when there are complications with the dissection or when the patients are relatively young (less than 60 years old) and would like to significantly enhance their long term chances of survival. Unlike in the case of surgery for ascending aorta where currently a highly invasive, open heart surgery is perhaps the only recommended option, 174 for dissections in descending aorta, a much less invasive surgery known as endovascular aortic repair (EVAR) is possible. In this method, there is no cutting open the chest; instead, grafts with stents are inserted through an incision in the groin and guided along to the position where the dissection needs to be sealed. EVAR for descending aortic dissections have gained significant acceptance worldwide since 2010, and especially since 2015 – and this was what the CMC surgeon was recommending for amma when I met him in 2017. 175
The advent of endovascular surgery for aortic dissection has significantly reduced in-operation and post-operative mortality by as much as 50%.
For aneurysms, the recommended course of treatment depends mainly on the location of the aneurysm, its size and the rate of growth of the aneurysm. Where the size of the aneurysm or its rate of growth is high, repair is recommended. With the growing popularity of EVAR procedure that carries much lower risks than open heart surgery, many of those with aneurysms who might have earlier opted for conservative management might today reconsider in favour of EVAR.
Similar to the procedure adopted for dissection repair, the use of EVAR for aneurysm involves a graft with stents inserted into the location where the aneurysm is present. The graft completely covers the dissection and reverts that part of the aorta to the way it was before the aneurysm, and the bulge usually shrinks over a period of time.
While aortic aneurysms are called ticking time bombs, it is not as if an aneurysm will burst immediately – estimates suggest that only about 5% of abdominal aortic aneurysms burst within a year.
While 5% looks like a small number, I guess it could be perceived as a much higher number by the person having the aneurysm!
Fig 52: Trends in aortic disease treatments. These vary depending on whether it is a dissection or aneurysm, and also depending on where on the aorta the dissection or aneurysm has happened.
170. Classification of aortic dissection Aortic dissections are done anatomically. The DeBakey classification system is most widely used: Type I (50% of dissections): These dissections start in the ascending aorta and extend at least to the aortic arch and sometimes beyond. Type II (35%): These dissections start in and are confined to the ascending aorta (proximal to the brachiocephalic or innominate artery). Type III (15%): These dissections start in the descending thoracic aorta just beyond the origin of the left subclavian artery and extend distally or, less commonly, proximally.
171. Open heart surgeries for the aorta can have mortality as high as 25% within the first one month. Complications of surgery include stroke (due to emboli), paraplegia (due to spinal cord ischemia), renal failure (especially if dissection includes renal arteries) and endoleak (leakage of blood back into the aneurysmal sac). The most important late complication includes re-dissection, formation of localized aneurysms in the weakened aorta, and progressive aortic regurgitation..
172. For acute uncomplicated type B dissection usually treated with blood pressure lowering medications, survival rates at 5 years averaged at 60%. http://jovs.amegroups.com/article/view/18861/18918
173. One key medication included in such conservative management is a blood pressure control drug that belongs to the class called beta blockers. These drugs need to be taken life-long, and they typically keep the systolic blood pressure at less than 110
174. Less invasive endovascular techniques could, at least theoretically, improve the results of ascending aortic repair. Endovascular repair has been now established for the descending thoracic and abdominal aorta and expansion of its application to the ascending aorta seems to be a natural evolutionary step Nevertheless, endovascular repair of the ascending aorta is not widely applied yet, since it is associated with additional challenges. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4999749/
175. The use of endovascular stent grafts for use in ascending aortic dissections are quite limited and selective. These are usually done on compassionate grounds in patients who present significant risks for open surgical repair.
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