Diseksi Aorta http://emedicine.medscape.com/article/2062452-overview#aw2aab6b2b4aa

DEFINISI

Diseksi Aorta (Aneurisma yang terbelah, Hematoma yang terbelah) adalah suatu keadaan yang sering berakibat fatal, dimana lapisan dalam dari dinding aorta mengalami robekan sedangkan lapisan luarnya utuh; darah mengalir melalui robekan dan membelah lapisan tengah serta membentuk saluran baru di dalam dinding aorta. DEFINISI

Diseksi aorta

Diseksi aorta

PENYEBAB

Sebagian besar diseksi aorta merupakan akibat dari kerusakan pada dinding arteri.

Yang paling sering menyebabkan kerusakan pada dinding arteri ini adalah tekanan darah tinggi, yang ditemukan pada lebih dari 65% penderita.

Penyebab lainnya adalah:

# Penyakit jaringan ikat turunan (sindroma Marfan dan sindroma Ehlers-Danlos)

# Kelainan bawaan pada jantung dan pembuluh darah (koartasio aorta, patent ductus arteriosus dan kelainan pada katup aorta)

# Arteriolosklerosis dan tekanan darah tinggi

# Cedera dada

Meskipun jarang, suatu diseksi bisa terjadi ketika dokter memasukkan selang ke dalam suatu arteri (misalnya pada aortografi atau angiografi) atau ketika melakukan pembedahan jantung dan pembuluh darah.

GEJALA

Penderita mengalami nyeri yang sangat luar biasa, yang muncul secara tiba-tiba.

Sebagian besar penderita menggambarkan dadanya seperti dicabik-cabik atau dirobek.

Nyeri juga sering dirasakan di punggung, diantara kedua bahu.

Nyeri sering mengikuti jalannya pembelahan di sepanjang aorta.

Pembelahan terus berlanjut, bisa menyebabkan terututupnya daerah dimana satu atau beberapa arteri berhubungan dengan aorta.

Tergantung kepada arteri mana yang tersumbat, bisa terjadi stroke, serangan jantung, nyeri perut mendadak, kerusakan saraf yang menyebabkan kesemutan dan ketidakmampuan menggerakan anggota badan.

DIAGNOSA

Diagnosis ditegakkan berdasarkan gejala-gejalanya yang khas.

Pada pemeriksaaan fisik, 65% penderita memiliki denyut nadi yang lemah atau sama sekali tidak teraba di tungkai dan lengan.

Diseksi aorta yang arahnya berbalik menuju ke jantung, bisa menyebabkan murmur, yang bisa terdengar melalui stetoskop.

Bisa terjadi penimbunan darah di dada.

Darah dari suatu diseksi yang merembes ke sekitar jantung bisa mengganggu denyut jantung dan menyebabkan tamponade jantung.

Foto rontgen menunjukkan pelebaran aota pada 90% penderita yang memiliki gejala.

Untuk memperkuat diagnosis bisa dilakukan pemeriksaan USG.

PENGOBATAN

Penderita dirawat di ruang perawatan intensif, dimana tanda-tanda vital (denyut nadi, tekanan darah dan laju pernafasan) diawasi secara ketat.

Kematian bisa terjadi dalam beberapa jam setelah terjadinya diseksi aorta. Karena itu segera diberikan obat untuk menurunkan denyut jantung dan tekanan darah sampai level yang terendah, untuk mempertahankan pasokan darah yang cukup ke otak, jantung dan ginjal.

Segera setelah diberikan obat-obatan, diputuskan apakah perlu dilakukan pembedahan atau cukup dengan melanjutkan pemakaian obat-obatan.

Hampir selalu dianjurkan untuk dilakukan pembedahan pada diseksi yang melibatkan aorta yang letaknya sangat dekat dengan jantung.

Untuk diseksi yang letaknya lebih jauh, biasanya diatasi dengan cara melanjutkan pemakaian obat-obatan; kecuali jika diseksi menyebabkan bocornya darah dari arteri dan penderita memiliki sindroma Marfan, maka dilakukan pembedahan.

Selama pembedahan dilakukan:

- pengangkatan sebanyak mungkin daerah aorta yang mengalami diseksi

- pencegahan masuknya darah ke saluran yang salah

- perbaikan aorta dengan cangkok buatan.

Jika katup aorta bocor, bisa sekaligus diperbaiki atau diganti.

Pengobatan untuk diseksi aorta harus dilakukan segera setelah diagnosis. Tujuan pengobatan darurat awal adalah untuk meringankan rasa sakit dan untuk mengurangi tekanan darah pada diseksi (pengurangan beban berdenyut). Ini membantu mencegah perdarahan tambahan dan mengurangi risiko pecahnya pembuluh darah.

Umumnya, Anda segera dimasukkan di unit perawatan intensif (ICU) atau dibawa ke ruang operasi. Dokter akan terus memantau dan mengontrol tekanan darah Anda, denyut nadi, dan aktivitas jantung.

Obat-obatan yang bertujuan untuk mengurangi rasa sakit dan tekanan darah akan digunakan dan mungkin termasuk:

* Nitroprusside, menurunkan tekanan darah. Tekanan darah arteri Anda seharusnya antara 60 dan 70 mm Hg. Tekanan ini biasanya menjamin aliran darah konstan ke organ dan meminimalkan tekanan pada diseksi tersebut. Nitroprusside menyebabkan pelebaran pembuluh arteri dan vena. Tekanan dalam sistem seluruh tubuh berkurang.

* Beta-blocker seperti Esmolol, Labetalol, Propranolol, etoprolol, , untuk menurunkan detak jantung Anda. Menurunkan tekanan darah akan menyebabkan refleks jantung alami yang meningkatkan kontraksi jantung dan denyut jantung. Hal ini dapat meningkatkan risiko pecah, sehingga beta-blocker akan diberikan. Anda harus menerima ini sebelum nitroprusside tersebut.

* Obat nyeri. Jika kontrol hipertensi tidak mengurangi rasa sakit, rasa sakit yang kuat obat dapat diberikan, termasuk morfin.

PROGNOSIS

Sekitar 75% penderita yang tidak diobati akan meninggal dalam 2 minggu pertama.

60% penderita yang diobati dan bertahan dalam 2 minggu pertama, bertahan hidup sampai 5 tahun setelah pengobatan; 40% bertahan hidup sampai 10 tahun setelah pengobatan.

Penderita yang meninggal dalam 2 minggu pertama, sekitar 30% meninggal karena komplikasi diseksi dan sisanya meninggal karena penyakit lainnya,.

Diberikan terapi obat jangka panjang untuk menjaga tekanan darah tetap rendah sehingga mengurangi tekanan terhadap aorta.

PENCEGAHAN

Cegah resiko terjadinya aterosklerosis akan secara signifikan mengurangi resiko terjadinya diseksi aorta. Dapat dilakukan dengan cara memperbaiki gaya hidup seperti

* berhenti merokok

* atur pola makan rendah garam dan kaya nutirsi

* bantu dengan obat - obatan hipertensi agar tekanan darah dapat terkontrol

1. Epidemiology

1. Gender: Most common in males by factor of 2-3 to 1

2. Age: 40-80 years old

3. Incidence: 2000 per year in US

2. Pathophysiology

1. Aortic Dissection has a very different mechanism than Abdominal Aortic Aneurysm

1. AAA is caused by atherosclerosis and involves all three layers of aorta wall

2. Aortic Dissection is caused by Hypertension and involves only one layer (intima)

2. Intimal tear precedes dissection

3. Risk Factors

1. Male gender

2. Pregnancy

3. Cocaine abuse or other Sympathomimetics

4. Chronic Hypertension (present in 70-90% of cases)

5. Bicuspid aortic valve

6. Aortic Coarctation

7. Giant Cell Arteritis

8. Cardiovascular procedures

1. Cardiac surgery

2. Cardiac catheterization

9. Connective Tissue Disease

1. Marfan's Syndrome

2. Ehlers-Danlos Syndrome

4. Types: Standford Classification

1. Type A (60-65%)

1. Ascending Aorta

2. Type B (30-35%)

1. Descending Aorta (after origin of subclavian artery)

5. Symptoms

1. Chest Pain (Universal)

1. Severe tearing sensation

2. Aortic Dissection pain radiates to back or Abdomen

1. Myocardial Infarction rarely radiates like this

3. Aortic Dissection pain is most severe at onset

1. Myocardial Infarction pain is crescendo in nature

2. Neurovascular symptoms

1. Cerebrovascular Accident

2. Syncope

6. Symptoms: Test Sensitivity at presentation with Aortic Dissection (based on IRAD Data)

1. Timing

1. Sudden onset: 85%

2. Severity

1. Severe pain: 90%

3. Characteristics

1. Sharp pain: 64%

2. Tearing/ripping: 50%

1. Type A: 49%

2. Type B: 52%

4. Distribution

1. Anterior Chest Pain: 61%

1. Type A: 71%

2. Type B: 44%

2. Back pain: 53%

1. Type A: 46%

2. Type B: 64%

3. Abdominal Pain: 35%

1. Type A: 22%

2. Type B: 42%

4. Migrating pain: 17%

1. Type A: 15%

2. Type B: 19%

5. Associated Findings

1. Pain: 95%

1. Type A: 94%

2. Type B: 98%

2. Syncope: 9%

1. Type A: 13%

2. Type B: 4%

7. Signs

1. Blood Pressure at presentation (based on IRADS results)

1. Hypertensive SBP>150: 49%

1. Type A: 36%

2. Type B: 70%

2. Normotensive SBP 100-150: 35%

3. Hypotensive or shock SBP: 16%

1. Type A: 25%

2. Type B: 4%

2. Pulse deficit: 15%

1. Type A: 19%

2. Type B: 9%

3. Aortic murmur: 30%

4. Cardiac Tamponade findings

5. Findings associated with dissection of hematoma

1. Cerebrovascular Accident

2. Hemiplegia

3. Pulse deficits

4. Aortic Insufficiency

8. Diagnosis

1. Electrocardiogram

1. Left Ventricular Hypertrophy

2. Myocardial Ischemia

3. Myocardial Infarction

2. Chest XRay

1. Mediastinal widening (progressive)

9. Imaging

1. Aortic Angiography (gold standard)

1. Accuracy

1. Sensitivity: 90-98%

2. Specificity: 95-98%

2. CT Chest

1. Sensitivity: 94%

2. Specificity: 90%

3. Transesophageal Echocardiogram (Increasingly popular)

1. Sensitivity: 97%

2. Specificity: 75-90%

4. MRI Chest

1. Sensitivity: 98%

2. Specificity: 98%

10. Complications

1. Neurologic deficits

1. Cerebrovascular Accident

2. Unequal perfusion

1. Unequal pulses

2. Unequal extremity Blood Pressures

3. Myocardial Ischemia

4. Myocardial Infarction

5. Aortic Regurgitation

6. Cardiac Tamponade

11. Management

1. Lower Blood Pressure

1. Nicardipine

2. Esmolol

3. Nitroprusside 0.5-10 ug/kg/min IV

4. Labetalol 20-40 mg incremental boluses IV

5. Trimethaphan 1-4 mg/min IV

2. Proximal Aortic Dissection

1. Surgical Management

3. Distal Aortic Dissection

1. Medical Management

12. References

1. Dachs (2012) Board Review Express, San Jose

2. Bushnell (2005) Ann Emerg Med 46:90-92

3. Gupta (2009) Pharmaceuticals 2: 66-76

4. Hagan (2000) JAMA 283: 897-203

Dissection of aorta (C0340643)

Definition (NCI) A progressive tear in the aorta characterized by a separation of the media layer from the outer-most layer.

Concepts Disease or Syndrome (T047)

ICD10 I71.0, I71.00

SnomedCT 308546005

English Dissection of aorta [any part], Aortic Dissection, dissection of aorta, dissection of aorta (diagnosis), Dissection of aorta, Aortic dissection, AORTA DISSECTION, aortic dissection, DISSECTION, AORTIC, AORTIC DISSECTION, Dissection of unspecified site of aorta, Dissection of aorta, unspecified site, dissection aorta, dissection aortic, aorta dissection, aorta dissections, aortic dissections, Dissection of aorta (disorder), dissection; aorta, aorta; dissection

Italian Dissezione dell'aorta

Japanese 大動脈解離, ﾀﾞｲﾄﾞｳﾐｬｸｶｲﾘ

German Dissektion der Aorta [jeder Abschnitt], Aortendissektion

Czech Aortální disekce

Korean 대동맥의 박리[모든 부분]

Hungarian Aorta dissectio

Dutch aorta; dissectie, dissectie; aorta, Dissectie van aorta [elk deel], aorta dissecans

Spanish disección aórtica (trastorno), disección aórtica, Disección aórtica

Portuguese Dissecção da aorta

French Dissection aortique

Sources

Derived from the NIH UMLS (Unified Medical Language System)

Aortic dissection is defined as separation of the layers within the aortic wall. Tears in the intimal layer result in the propagation of dissection (proximally or distally) secondary to blood entering the intima-media space. An acute aortic dissection (< 2 wk) is associated with high morbidity and mortality rates. Mortality is highest in the first 7 days; indeed, many patients die before presentation to the emergency department (ED) or before diagnosis is made in the ED. Patients with chronic aortic dissection (>2 wk) have a better prognosis. The aortic dissection mortality rate is still high despite advancements in diagnostic and therapeutic modalities.[1, 2]

Although acute aortic dissection classically produces sudden onset of severe chest pain that often has a tearing or ripping quality, no one sign or symptom can positively identify acute aortic dissection. The clinical manifestations are diverse, making the diagnosis difficult and requiring a high index of suspicion.[1, 3, 2] (See Presentation.) An estimated 38% of acute aortic dissections are missed on initial evaluation.[4, 5, 6]

There are no validated clinical decision rules to help identify acute aortic dissection. The diagnosis is best made when there is high clinical suspicion. A good patient history and physical examination are essential, along with imaging studies, electrocardiography, and laboratory studies (see Workup).

Acute aortic dissection can be treated surgically or medically. In surgical treatment, the area of the aorta with the intimal tear is usually resected and replaced with a Dacron graft. (See the Treatment section and the Medication section.)

For patient education information, see the Heart and Blood Vessels Center, Circulatory Problems Center, and Heart Center, as well as Chest Pain.

History of aortic dissection and its repair

The first well-documented case of aortic dissection occurred in 1760, when King George II of England died while straining on the commode. In 1761, the celebrated Italian anatomist Giovanni Battista Morgagni provided the first detailed pathologic description of aortic dissection.

Aortic dissection was associated with a high mortality rate before the introduction of the cardiopulmonary bypass in the 1950s, which led to aortic arch repair and construction. DeBakey performed the first successful operative repair in 1955.

Modern techniques of diagnosing and repairing thoracic aortic dissections transformed the condition from a death sentence to a treatable disorder—as shown by the experience of Dr. DeBakey himself, who developed aortic dissection at age 97, and at age 98 became the oldest patient to survive the surgical procedure he pioneered.[7]

Recent advances in the field of stent placement and percutaneous aortic fenestrations have further reduced mortality rates. However, despite these advances, the mortality rate associated with aortic dissection remains high, as illustrated by the deaths of Princess Diana, actor John Ritter, and diplomat Richard Holbrooke.[1, 2]

Pathophysiology

The aortic wall is exposed to high pulsatile pressure and shear stress (the steep slope of the pressure curve; ie, the water hammer effect), making the aorta particularly prone to injury and disease from mechanical trauma. The aorta is more prone to rupture than any other vessel, especially with the development of aneurysmal dilatation, because its wall tension, as governed by the Laplace law (proportional to the product of pressure and radius), is intrinsically high.

An aortic dissection is a split or partition in the media of the aorta; this split is frequently horizontal or diagonal. An intimal tear connects the media with the aortic lumen, and an exit tear creates a true lumen and a false lumen, resulting in a double-barreled aorta (see the image below).

Aortic dissection. True lumen and false lumen sepaAortic dissection. True lumen and false lumen separated by an intimal flap.

The true lumen is lined by intima, and the false lumen is within the media. Although the false lumen is within the media, suggesting that it is "lined" with media is misleading; if the aortic dissection becomes chronic, the lining becomes a serosal pseudointima.

The true lumen is frequently smaller than the false lumen, but not invariably. Typically, flow in the false lumen is slower than in the true lumen, and the false lumen often becomes aneurysmal when subjected to systemic pressure. The dissection usually stops at an aortic branch vessel or at the level of an atherosclerotic plaque.

Most classic aortic dissections begin at one of the following 3 distinct anatomic locations:

*

Approximately 2.2 cm above the aortic root

*

Distal to the left subclavian artery

*

The aortic arch

The most common site of dissection is the first few centimeters of the ascending aorta, with 90% occurring within 10 cm of the aortic valve. The second most common site is just distal to the left subclavian artery. Between 5 and 10% of dissections do not have an obvious intimal tear. These often are attributed to rupture of the aortic vasa vasorum as first described by Krukenberg in 1920.

Keeping the descending aorta in mind is important. The descending aorta is the location of most late clinical events after any dissection of the aorta.[9]

Ascending aortic involvement may result in death from wall rupture, hemopericardium and tamponade, occlusion of the coronary ostia with myocardial infarction, or severe aortic insufficiency. The nervi vascularis (ie, bundles of nerve fibers found in the aortic adventitia) are involved in the production of pain.

Classification

Two major anatomic classification schemes for aortic dissection are the DeBakey and the Stanford systems (see the images below).

DeBakey and coworkers classify aortic dissection into 3 types, as follows:

*

Type I: the intimal tear occurs in the ascending aorta, but the descending aorta is also involved

*

Type II: only the ascending aorta is involved

*

Type III: only the descending aorta is involved; type IIIA originates distal to the left subclavian artery and extends as far as the diaphragm, while type IIIB involves the descending aorta below the diaphragm

The Stanford classification has 2 types, as follows:

*

Type A: the ascending aorta is involved (DeBakey types I and II)

*

Type B: the descending aorta is involved (DeBakey type III)

This system also helps delineate treatment. Type A dissections usually require surgery, whereas type B dissections are managed medically under most conditions.[10]

Image A represents a Stanford A or a DeBakey type Image A represents a Stanford A or a DeBakey type 1 dissection. Image B represents a Stanford A or DeBakey type II dissection. Image C represents a Stanford type B or a DeBakey type III dissection. Image D is classified in a manner similar to A but contains an additional entry tear in the descending thoracic aorta. Note that a primary arch dissection does not fit neatly into either classification.

Etiology

Congenital and acquired factors, alone or in combination, can lead to aortic dissection. Aortic dissection is more common in patients with hypertension, connective tissue disorders, congenital aortic stenosis, or a bicuspid aortic valve,[11] as well as in those with first-degree relatives with a history of thoracic dissection. These diseases affect the media of the aorta and predispose it to dissection.

Congenital causes

Aortopathy may be due to the following heritable diseases:

*

Marfan syndrome

*

Ehlers-Danlos syndrome

*

Annuloaortic ectasia

*

Familial aortic dissections

*

Adult polycystic kidney disease

*

Turner syndrome

*

Noonan syndrome

*

Osteogenesis imperfecta

*

Bicuspid aortic valve

*

Coarctation of the aorta

*

Connective tissue disorders

*

Metabolic disorders (eg, homocystinuria, familial hypercholesterolemia)

Acquired conditions

Arterial hypertension is an important predisposing factor for aortic dissection.[2] Of patients with aortic dissection, 70% have elevated blood pressure. Hypertension or pulsatile blood flow can propagate the dissection.

Pregnancy can be a risk factor for aortic dissection, particularly in patients with an underlying anomaly such as Marfan syndrome. An estimated 50% of all cases of aortic dissection that occur in women younger than 40 years are associated with pregnancy. Most cases occur in the third trimester or early postpartum period.

Other acquired causes of aortic dissection include the following:

*

Syphilitic aortitis

*

Deceleration injury possibly with related chest trauma

*

Cocaine use

Cystic medial necrosis

The normal aorta contains collagen, elastin, and smooth muscle cells that contribute the intima, media, and adventitia, which are the layers of the aorta. With aging, degenerative changes lead to breakdown of the collagen, elastin, and smooth muscle and an increase in basophilic ground substance. This condition is termed cystic medial necrosis. Atherosclerosis that causes occlusion of the vasa vasorum also produces this disorder. Cystic medial necrosis is the hallmark histologic change associated with dissection in those with Marfan syndrome.

Cystic medial necrosis was first described by Erdheim in 1929. Sources disagree over the accuracy of this term in elderly patients because the true histopathologic changes are neither cystic nor necrotic. Researchers have used the term cystic medial degeneration.

Early on, cystic medial necrosis described an accumulation of basophilic ground substance in the media with the formation of cystlike pools. The media in these focal areas may show loss of cells (ie, necrosis). This term still is used commonly to describe the histopathologic changes that occur.

Iatrogenic causes

Iatrogenic aortic dissection can result from cardiologic procedures such as the following:

*

Aortic and mitral valve replacements

*

Coronary artery bypass graft surgery

*

Percutaneous catheter placement (eg, cardiac catheterization, percutaneous transluminal coronary angioplasty)

Aortic dissection occurs when the layers are split in the process of cannulation or aortotomy.

Anatomy

The aorta is composed of the intima, media, and adventitia. The intima, the innermost layer, is thin, delicate, lined by endothelium, and easily traumatized.

The media is responsible for imparting strength to the aorta and consists of laminated but intertwining sheets of elastic tissue. The arrangement of these sheets in a spiral provides the aorta with its maximum allowable tensile strength. The aortic media contains very little smooth muscle and collagen between the elastic layers and thus has increased distensibility, elasticity, and tensile strength. This contrasts with peripheral arteries, which, in comparison, have more smooth muscle and collagen between the elastic layers.

The outermost layer of the aorta is adventitia. This largely consists of collagen. The vasa vasorum, which supplies blood to the outer half of the aortic wall, lies within the adventitia. The nervi vascularis, bundles of nerve fibers found in the aortic adventitia, are involved in the production of pain, which occurs with acute stretching of the aortic wall from a dissection.[8] .The aorta does not have a serosal layer.

The aorta plays an integral role in the forward circulation of the blood in diastole. During left ventricular contraction, the aorta is distended by blood flowing from the left ventricle, and kinetic energy from the ventricle is transformed into potential energy stored in the aortic wall. During recoil of the aortic wall, this potential energy is converted to kinetic energy, propelling the blood within the aorta to the peripheral vasculature.

The volume of blood ejected into the aorta, the compliance of the aorta, and resistance to blood flow are responsible for the systolic pressures within the aorta. Resistance is mainly due to the tone of the peripheral vessels, although the inertia exerted by the column of blood during ventricular systole also plays a small part.

The aorta has thoracic and abdominal regions. The thoracic aorta is divided into the ascending, arch, and descending segments; the abdominal aorta is divided into suprarenal and infrarenal segments. The ascending aorta is the anterior tubular portion of the thoracic aorta from the aortic root proximally to the innominate artery distally. The ascending aorta is 5 cm long and is made up of the aortic root and an upper tubular segment.

The aortic root consists of the aortic valve, sinuses of Valsalva, and left and right coronary arteries. It extends from the aortic valve to the sinotubular junction and supports the base of the aortic leaflets. The aortic root allows the 3 sinuses of Valsalva to bulge outward, facilitating the full excursion of the leaflets in systole. The left and right coronary arteries arise from these sinuses.

The upper tubular segment of the ascending aorta starts at the sinotubular junction and ends at the beginning of the aortic arch. The ascending aorta lies slightly to the right of the midline, with its proximal portion in the pericardial cavity. Structures around the aorta include the pulmonary artery anteriorly; the left atrium, right pulmonary artery, and right mainstem bronchus posteriorly; and the right atrium and superior vena cava to the right.

The arch of the aorta curves upward between the ascending aorta and descending aorta. The brachiocephalic arteries originate from the aortic arch. Arteries that arise from the aortic arch carry blood to the brain via the left common carotid, innominate, and left subclavian arteries.

The initial part of the aortic arch lies slightly left and in front of the trachea; the arch ends posteriorly to the left of the trachea and esophagus. Inferior to the arch is the pulmonary artery bifurcation, the right pulmonary artery, and the left lung. The recurrent laryngeal nerve passes beneath the distal arch, and the phrenic and vagus nerves lie to the left. The junction between the aortic arch and the descending aorta is called the aortic isthmus. The isthmus is a common site for coarctations and trauma.

The descending aorta extends from the area distal to the left subclavian artery to the 12th intercostal space. Initially, the descending aorta lies in the posterior mediastinum to the left of the course of the vertebral column. It passes in front of the vertebral column in its descent and ends behind the esophagus before passing through the diaphragm at the level of the 12th thoracic vertebra.

The abdominal aorta extends from the descending aorta at the level of the 12th thoracic vertebra to the level of bifurcation at the fourth lumbar vertebra. The splanchnic arteries branch from the

abdominal aorta. The thoracoabdominal aorta is the combination of the descending thoracic and abdominal aorta.

With increasing age, the elasticity and distensibility of the aorta decline, thus inducing the increase in pulse pressure observed in elderly individuals. The progression of this process is exacerbated by hypertension, coronary artery disease, or hypercholesterolemia.

Histologically, the loss of distensibility is marked by fragmentation of elastin and the resultant increase in collagen and, thus, a higher collagen-to-elastin ratio. This, along with impairment in flow in the vasa vasorum, may be responsible for the age-related changes. These factors cumulatively lead to increased left ventricular systolic pressure and wall tension with associated increases in end-diastolic pressure and volume.