Embolism
Thrombosis
No previous symptoms
History of claudication
Obvious source of emboli (atrial fibrillation, myocardial infarction, aorta, popliteal aneurysm)
No source of emboli (atheromatosis, vessel stenosis)
Sudden onset
Long history
Normal contralateral pulses
Lack of pulses
Severe ischemia
Less severe ischemia
No signs of chronic ischemia
Signs of chronic ischemia
27.1.1.1 Clinical Signs and Symptoms
Irrespective of the presence of embolism or thrombosis, the symptoms and signs of acute ischemia are usually associated to the “6 Ps,” whose intensity, particularly related to sensory and motor function, correlates quite well with the severity of the ischemic process.
Pain – Severe, continuous, and localized initially more distally in the extremity.
Pallor – The ischemic extremity is pale and appears to be “empty” with skinfolds, but may become cyanotic with worsening ischemia.
Pulseless – When in doubt, as in diabetic or obese patients, an ankle blood pressure can be measured with a continuous Doppler device.
Paresthesia and paralysis – The nerve fibers (sensory and motor) are very sensitive to ischemia, and loss of motor function must be interpreted as a sign of marked severity or eventually irreversible ischemia.
Poikilothermia – Low skin temperature remains constant regardless the surrounding temperature (Table 27.2).
Table 27.2
Classification of severity of ischemia
Limb
Sensibility
Motor function
Arterial Doppler signal
Venous Doppler signal
I
Viable
Normal
Normal
Audible (>30 mmHg)
Audible
IIa
Marginally threatened
Decreased or normal in toes
Normal
Not aud.
Audible
IIb
Immediately threatened
Decreased even in toes
Moderately affected
Not aud.
Audible
III
Irreversibly damaged
Extensive anesthesia
Paralysis rigor
Not aud.
Not aud.
27.1.1.2 Decision Making
If limb is irreversibly damaged, the best option is urgent amputation.
For evaluation of irreversibility, do not rely on time of ischemia, but rather on motor function and venous Doppler signal.
If the limb is viable or marginally threatened, consider to treat or transfer the patient to a vascular specialized unit, depending on the local resources and individual experience.
If the limb is immediately threatened, the patient should be prepared for emergent operation.
When there is no cyanosis and motor function is normal (marginally threatened extremity), there is time for immediate angiography followed by thrombolysis or operation.
The surgeon needs to be aware of the need to perform a complete vascular reconstruction.
Bypass to the popliteal artery or a calf artery will be required to restore circulation particularly in cases of thrombosis.
In the vast majority of cases of embolism, embolectomy is usually the procedure of choice.
In cases requiring a transfer to higher level of care, initiating systemic heparinization prior to transport is indicated.
27.1.1.3 Embolectomy
Embolectomy with balloon catheters (Fogarty catheters)
One of the most common emergency vascular operations.
Does not require experience in complex vascular procedures.
Before using, check the balloon by insufflation of a suitable volume of saline.
External markers of the relationship between the catheter length and important anatomical structures should be recognized.
For example, the aortic bifurcation is located at the level of the umbilicus.
The popliteal trifurcation is located approximately 10 cm below the knee joint.
The catheters have centimeter markings, which simplify the orientation.
Principles are the same for upper and lower limb.
Incisions.
For the upper limb, the brachial artery
Is exposed by medial incision, middle third of the arm, parallel to the biceps gutter
Is controlled proximally and distally with vessel loops or Rummel tourniquets
Make a transverse arteriotomy
For the lower limb, the common, superficial, and deep femoral arteries
Are exposed by longitudinal incision in the skin
Make a short longitudinal arteriotomy (about 15 mm)
Placed over the origin of the profunda artery so it can be inspected and cleared
Longitudinal arteriotomy preferable because it can be used as the site for the inflow anastomosis of a bypass
For proximal embolectomy, a # 4 or 5 Fogarty catheter is used.
Insert the catheter proximally; prevent excessive bleeding via the arteriotomy by applying tension on the vessel loop or by a thumb–index finger grip over the artery and the catheter.
The catheter should be inserted both proximally (beware of immediate gush) and distally (#3 or #4 catheter is recommended).
Typically, an embolus can be passed with only slight resistance.
Traction must be gentle, parallel to the vessel axis.
Repeat the maneuver until
The catheter no longer retrieves embolic material.
There is an acceptable backflow from the distal vascular bed
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