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What are the causes of radiofemoral delay

Normally the radial and femoral pulses are palpated simultaneously.If there an appreciable delay in the femoral pulse compared to radial pulse it is called as radiofemoral delay.
Radiofemoral delay is seen in following conditions
1. Coarctation of aorta
2. Aortoarteritis
3. Atheroslerosis of aorta
4. Thrombosis or embolism of aorta.    
1. Coarctation of aorta
Coarctation of the aorta may lead to hypertension in the circulatory system serving the head and upper limbs.It is an important bedside diagnostic clue in a young hypertensive patients
Narrowing or constriction of the aortic lumen may occur anywhere along its length but it is most common distal to the origin of the left subclavian artery near the insertion of the ligamentum arteriosum. Coarctation is seen in approximately 7% of patients with congenital heart disease,this  is more common in males than females, and is particularly frequent in patients with gonadal dysgenesis for example Turner syndrome. 
Clinical manifestations of coarctaion of aorta is dependent on the following factors
  • The site and extent of obstruction 
  • Presence of associated cardiac anomalies
The most common congenital heart disease associated with coarctation is a bicuspid aortic valve. Circle of Willis aneurysms is seen in up to 10%, and pose a high risk of sudden rupture and death.
2. Aortoarteritis.
Aortitis, a term referring to inflammatory disease of the aorta, it may be caused by
  • Large vessel vasculitides such as Takayasu’s arteritis and giant cell arteritis,
  • Rheumatic and HLA-B27–associated spondyloarthropathies
  • Beh├žet’s syndrome
  • Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides
  • Cogan’s syndrome
  • Infections such as syphilis, tuberculosis, and Salmonella
Clinical presentation of aortitis
Aortitis may result in th following features
  • Aneurysmal dilation and aortic regurgitation
  • Occlusion of the aorta and its branch vessels
  • Acute aortic syndromes.
Prototype of aortoarteritis is takayasu arteritis its signs and symptoms are given below
There are two phases for this disease.Initial inflammatory phase followed by secondary pulseless phase.
Initial "inflammatory phase"
Initial "inflammatory phase" characterized by systemic illness with signs and symptoms of malaise, fever, night sweats, weight loss, joint pain, fatigue, and fainting is seen in some patients. 
Fainting episodes are due to subclavian steal syndrome or carotid sinus hypersensitivity. Nonspecific markers of inflammation such as anemia and marked elevation of the ESR or C-reactive protein is seen. 
Secondary pulseless phase
The "pulseless phase" is characterized by vascular insufficiency due to intimal narrowing of the vessels presenting as
  • Arm or leg claudication
  • Renal artery stenosis causing hypertension, 
  • Neurological features due to decreased blood flow to the brain.These symptoms vary depending on the degree and  the nature of the blood vessel obstruction; it can range from lightheadedness to seizures in severe cases
  • One rare,but important feature of the Takayasu's arteritis is eye involvement in form of visual field defects, vision loss, or retinal haemorrhage
Some individuals with Takayasu's arteritis may present with only late vascular changes, without a preceding inflammatory phase
In the advanced stage, weakness of the arterial walls may give rise to localized aneurysms. And there is risk of rupture and vascular bleeding so requires frequent monitoring. 
3. Atherosclerosis of aorta.
Atherosclerosis may affect the either the thoracic and abdominal aorta. 
Occlusive aortic disease caused by atherosclerosis usually it is a confined to the distal part of abdominal aorta below the origin of renal arteries.Frequently the disease extends to the iliac arteries Claudication pain involves the buttocks, thighs, and calves muscle and may be associated with impotence in males (Leriche syndrome)
The severity of the clinical presentation  depends on the adequacy of collaterals.If there is sufficient collateral blood flow, even a complete occlusion of the abdominal aorta can occur without the development of ischemic symptoms.
The physical findings include the following
  • Absence of femoral and other distal pulses bilaterally 
  • An audible bruit over the abdomen (usually at or below the umbilicus) and the common femoral arteries. 
  • Atrophic skin, loss of hair, and coolness of the lower extremities 
  • In advanced cases of ischemia, rubor on dependency and pallor on elevation may be observed.
The diagnosis of atherosclerosis of aorta is usually established by physical examination and noninvasive testing which include
  • Leg pressure measurements,
  • Doppler velocity analysis
  • Pulse volume recordings
  • Duplex ultrasonography. 
  • The extend of lesion may be defined by MRI, CT, or conventional aortography, specifically performed for the purpose of  revascularization. 
Catheter-based endovascular or operative treatment is indicated in patients with lifestyle-limiting or debilitating symptoms of claudication and in patients with critical limb ischemia.
4. Thrombosis or embolism of aorta.
Acute occlusion in the distal abdominal aorta is a medical emergency as it threatens the viability of the lower extremities; This is usually from an occlusive or saddle embolus that almost always originates from the heart. Rarely, acute occlusion of aorta may be seen as a  result of in situ thrombosis in a preexisting severely narrowed segment of the aorta.
The clinical picture is one of acute ischemia of the lower extremities. 
  • Severe rest pain
  • Coolness, and pallor of the lower extremities and the absence of distal pulses bilaterally are the usual manifestations.
Diagnosis is by MRI, CT, or aortography.
Emergency thrombectomy or revascularization is the treatment.