Human diseases Research and textbook: 1

By Aliasghar Tabatabaei Mohammadi, Narjes sadat Farizani gohari, Saina Karami and 10 more

Research and textbook about human diseases.
For medical doctors and researchers.

• Language: English
• Publisher: Nobel TM
• Release date: Mar 25, 2023
• ISBN: 9791222087085

Book preview

The inherited thoracic aortic aortopathies

The hereditary aortopathies that influence the thoracic aorta could be roughly categorized as syndromic and non-syndromic, with the syndromic category consisting of the aortopathies linked to the bicuspid aortic valve, such as Marfan Syndrome, Loeys Dietz syndrome, and Ehlers Danlos syndrome.

Marfan syndrome

Lots of patients with Marfan syndrome have polymorphisms in the fibrillin-1 (FBN1) gene, which codes for the glycoprotein fibrillin-1. Marfan syndrome is inherited in an autosomal dominant manner and is defined by a series of clinical characteristics. This is a crucial part of the aorta wall's extracellular matrix, and its absence reduces both the production of elastic fibers and their ability to adhere to the vascular smooth muscle cells (5). The aortic wall subsequently enlarges as an outcome.

Loeys dietz syndrome

The TGFBR1 or TGFBR2 genes, which encode the transforming growth factors involved in cell signaling that stimulates the growth and development of body cells, are the cause of Loey-Dietz Disorder. This condition is defined by mutations that impact these genes, leading to a variety of clinical abnormalities, such as widely separated eyes, split uvulas or split palates, twisted arteries, and, of course, aortic aneurysms ( 6 ).

Ehlers-danlos syndrome

Ehlers-Danlos syndrome (EDS) is distinguished by cellular instability, joint hypermobility, and epidermal hyperextensibility (7). It has several subgroups and is inherited in an autosomal dominant manner. Clients with cardiovascular EDS struggle in especially with arterial wall fragility (5). At an average age of 36 years old, aortic dissection or breach occurs in up to 6% of people with vascular EDS.

Bicuspid aortopathy

Approximately 2% of people in the general population have the bicuspid aortic valve (BAV) (8). Although this exact methods by which BAV induces aortic dilatation are still up for discussion, these are generally believed to result from both biomechanical and genetic factors. Numerous investigations have shown that by removing the bicuspid source, or the bicuspid aortic valve, the aorta's dilation may be stopped (9, 10). Apart from this, some clients who recently underwent bicuspid aortic valve replacement will require intervention for either a dilated or dissected increasing aorta, indicating that a hereditary basis for dilatation may also occur ( 11 ).

Intervention for aortic arch aneurysm

Open surgical intervention

There are several accepted methods to consider when considering intervention for aortic arch aneurysm.

The amount of aortic arch involvement by aneurysmal illness determines the method of surgical repair of the aortic arch. All kinds of surgical aortic arch replacements involve the replacing of the ascending aorta, with or without replacing of the aortic root, and often involve cardiopulmonary bypass with profound hypothermia and circulatory arrest. The following are the two primary methods:

- Hemi-aortic arch replacement: In this case, the head and neck arteries are left alone while the aortic arch is restored. A single anastomosis is made utilizing an obliquely angled piece of woven polyethylene graft to the residual thoracic aorta, providing the head and neck vessels are not aneurysmal or involved with aortic dissection. Comparatively speaking, which demands a significantly shorter period of circulatory stoppage than full arch replacements.

- Total aortic arch replacement: Full excision of the aortic arch is required, along with disconnection of the head and neck vessels. It can be accomplished in one of two ways: either by expunging a island of aorta that contains the head and neck vessels and anastomosing this island to the vascular transplants, either by separating evey head and neck vessel individually and anastomosing each one to a specialized vascular transplants with pre-formed sections to.

Both of these procedures enable and frequently involve replacement of the distal aorta. Retrograde cerebral circulation, which involves oxygenated blood getting carried backwards through the SVC and the cerebral venous circuit as deoxygenated blood is expelled from the cerebral arterial veins, is another technique of cerebral prevention in addition to profound hypothermia. This approach is especially helpful when brief (<30 min) periods of profound hypothermia are anticipated, such as during hemi-aortic arch replacement. Selective antegrade cerebral perfusion is an alternate technique where prolonged circulatory arrest durations are anticipated. Oxygenated blood is transported in an antegrade style through the cerebral artery route (12). Our clinic often provides targeted antegrade perfusion by inserting perfusion catheters into the left common carotid artery and innominate artery and supplying oxygenated blood through these passageways. This supplies the head with an ideal metabolism state during deep hypothermia and has been shown to offer exceptional neuroprotection also during prolonged periods of circulatory arrest (12).

Guidelines for surgical intervention

According to anatomical parameters, the most recent global recommendations offer suggestions for when to treat on the aortic root and ascending aorta along with the aortic arch.

Guidelines for the management of aortic disease were released by the AHA and ESC in 2010 and 2014, respectively. Both advise patients with an isolated aortic arch dimension of more than 5.5 cm to seek operation (3, 13). The recommendations are less obvious, though, when it comes to replacing the arch while a person is also having their nearby ascending aorta replaced. Given the higher perioperative risks, they advise weighing the advantages of operation against the risks before doing any arch treatments.

Intervening in inherited aortopathy

The therapy of the aortic arch in people with connective tissue diseases and hereditary aortopathy has been proposed to utilize a more aggressive treatment, even if standards would advise replacing the aortic arch when the arch diameter is >5.5 cm.

Just 4 of 25 patients who had previously undergone root replacement at the time of reoperation needed an arch replacement, according to Bachet et al. on 54 clients with Marfan syndrome who underwent thoracic aorta replacement. Several of these clients had undergone reoperative surgical procedure after undergoing proximal aortic restoration. They came to the conclusion that it was not necessary to repair the aortic arch prophylactically in Marfan syndrome individuals undergoing proximal aortic operations (14). However, given that Marfan patients frequently divide at lower dimensions, they did suggest a lower threshold for surgery for Marfan patients with