A 35-year-old woman from rural India presents with progressive dyspnea, chest pain, and signs of aortic regurgitation. Angiography shows narrowing of the aorta and its major branches with a 'skip lesion' pattern. Which is the most common site of initial vascular involvement in this condition?

Question

Accepted Answer

B. Aortic arch and proximal branches (subclavian, carotid, vertebral). ## Takayasu Arteritis: Pattern of Vascular Involvement

**Key Point:** Takayasu arteritis (TA) is a large-vessel vasculitis that predominantly affects the aorta and its proximal branches. The aortic arch and its immediate branches (subclavian, common carotid, and vertebral arteries) are the **most commonly and characteristically involved** sites.

### Epidemiology & Demographics
- Predominantly affects young women (female:male = 8:1)
- Most common in Asia, particularly India, Japan, and Southeast Asia
- Peak incidence: 15–30 years of age

### Pattern of Vascular Involvement

| Aortic Region | Frequency | Clinical Features |
|---|---|---|
| **Aortic arch & proximal branches** | **~60–70%** | **Most common; arm claudication, absent pulses** |
| Ascending aorta/aortic root | ~30% | Aortic regurgitation, aortic root dilation |
| Descending thoracic aorta | ~40% | Often concurrent with arch involvement |
| Abdominal aorta | ~30% | Renal artery stenosis → hypertension |
| Pulmonary arteries | ~10–15% | Pulmonary hypertension |
| Coronary arteries | ~10% | Myocardial ischemia, MI |

**High-Yield:** The **aortic arch and its proximal branches (subclavian, carotid, vertebral)** are the most frequently affected sites, occurring in 60–70% of cases. This is the hallmark distribution that distinguishes TA from other large-vessel vasculitides.

### Pathological Features
- Granulomatous inflammation of the media and adventitia
- Giant cells and epithelioid histiocytes (similar to GCA)
- Intimal proliferation and fibrosis → stenosis and narrowing
- **Skip lesions** = alternating areas of involvement and normal vessel (pathognomonic)

### Clinical Manifestations by Site

**Aortic arch involvement:**
- **Pulseless disease** = absent pulses in upper extremities
- Arm claudication and blood pressure differential between arms
- Subclavian steal syndrome
- Carotid involvement → dizziness, syncope

**Ascending aorta/aortic root:**
- Aortic regurgitation (most common cardiac complication)
- Aortic root dilation
- Heart failure

**Abdominal aorta/renal arteries:**
- Hypertension (from renal artery stenosis)
- Mesenteric ischemia (rare)

**Pulmonary arteries:**
- Pulmonary hypertension
- Right heart failure

**Clinical Pearl:** The combination of **young woman + aortic arch stenosis + aortic regurgitation + skip lesions on angiography** is virtually pathognomonic for Takayasu arteritis. The "pulseless disease" phenotype (absent upper extremity pulses) is a classic presentation.

**Mnemonic: TAKAYASU** — **T**horacic aorta, **A**ortic arch, **K**ey branches (subclavian/carotid), **A**bdominal aorta (less common), **Y**oung women, **A**sia, **S**tenosis/Skip lesions, **U**pper extremity claudication.

**Warning:** Do not confuse with Giant Cell Arteritis (GCA), which affects **extracranial branches of the carotid system** (temporal artery) and occurs in elderly patients (>50 years). TA is a disease of young women; GCA is a disease of elderly.

Answer

A. Abdominal aorta and renal arteries

Answer

C. Descending thoracic aorta

Answer

D. Ascending aorta and aortic root

A 35-year-old woman from rural India presents with progressive dyspnea, chest pain, and signs of aortic regurgitation. Angiography shows narrowing of the aorta and its major branches with a 'skip lesion' pattern. Which is the most common site of initial vascular involvement in this condition?

Explanation

Takayasu Arteritis: Pattern of Vascular Involvement

Epidemiology & Demographics

Pattern of Vascular Involvement

Pathological Features

Clinical Manifestations by Site

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Aortic Region	Frequency	Clinical Features
Aortic arch & proximal branches	~60–70%	Most common; arm claudication, absent pulses
Ascending aorta/aortic root	~30%	Aortic regurgitation, aortic root dilation
Descending thoracic aorta	~40%	Often concurrent with arch involvement
Abdominal aorta	~30%	Renal artery stenosis → hypertension
Pulmonary arteries	~10–15%	Pulmonary hypertension
Coronary arteries	~10%	Myocardial ischemia, MI