Feblography

Alternative names

Venography, venogram

Definition

The venous system is responsible for conducting blood from the organs to the heart in order to oxygenate it. In the lower extremities, the venous system can be classified as superficial and deep. The superficial venous system is formed by the superficial veins of the extremities, including those that are located in the subcutaneous tissue on the soles of the feet. The deep venous system is under the muscle tissue. Both systems are connected to allow correct venous return. Venography consists of an invasive diagnostic examination that allows the study of the venous circulation of the lower extremities. The veins are not visible on plain radiographs. To be able to visualize them by means of an X-ray study, the injection of a venous contrast is necessary. Contrast is a radiopaque substance that does not allow X-rays to pass through its surface, thus allowing the visualization of those veins that contain it. During the practice of the test, several radiographs can be taken to visualize the progressive filling of the vessels and to detect narrowing, obstructions or the presence of abnormal vessels. Currently there are other non-invasive techniques that also allow the study of venous circulation. The use of phlebography has been relegated to those cases in which ultrasound does not allow the diagnosis.

How it is performed?

It is performed in radiology rooms or units. The patient must have bare legs, especially avoiding the presence of metallic objects that could alter the images. The limbs are attached to an X-ray table. The table can be tilted in various positions. One of the superficial veins of the lower limb to be studied is channeled, generally on the back of the foot, and the contrast will be injected. A local anesthetic may be applied to numb the area where the catheter will be inserted, as it may sometimes require a small incision to facilitate insertion of the catheter. Nursing staff monitor vital signs and check dorsal foot, popliteal, and femoral pulses. The patient is instructed not to move the leg while the x-rays are being taken. The approximate duration of an uncomplicated venography is about thirty minutes. Once the catheter is finished, the catheter is removed and a bandage is applied over the puncture site, which can be removed the following day. In the six hours after the procedure it is advisable to keep the leg extended. After this period, the patient can return home.

Preparation for the study

Fasting should be done in the 6 hours prior to the test. The healthcare staff will shave the puncture area in those cases where it is necessary. It is important that the responsible doctor is aware of the patient's usual treatments or a history of allergies. If the patient is undergoing anticoagulant treatment, the attending physician will assess the possibility of removing it before the examination.

What does it feel like during and after the study?

A slight burning sensation may be felt during the injection of the contrast. The puncture site may remain sore for up to a few days. Once at home, avoid climbing stairs and any strenuous activity. During the 24 hours after the test it is important to drink plenty of water, which facilitates the elimination of the administered contrast.

Study risks

In general, phlebography is a safe technique, but it is not without risks, since it is an invasive examination. The contrasts used are generally safe and have minimal side effects. The most common are nausea, vomiting, and itching. More infrequent would be dizziness, cough, headache or abdominal pain. In the most serious cases and exceptionally, the patient could present an allergic reaction with respiratory distress, altered heart rhythm, blood pressure, severe allergic reaction or anaphylactic shock. These serious adverse effects are more likely in patients who suffer from some type of allergy and especially in those who have previously suffered an adverse reaction to contrast agents. In the case of women, if there is any possibility that you are pregnant, it is important to inform the doctor before the venography. The radiological study is based on the emission of ionizing radiation that can be detrimental to the correct development of the fetus. Other risks inherent to the technique is the appearance of a hematoma, cellulitis and thrombophlebitis. You should consult your doctor in the event that after the examination the pain worsens, the limb swells, local heat or fever appears.

Study contraindications

allergy to contrast, immobile uncooperative patient, intolerance to decubitus and pregnant women.

Reasons why the study is carried out

Phlebography is a useful diagnostic technique for the diagnosis of venous diseases. Currently, with the development of ultrasound, its indications have become more limited, but it is still useful in those cases in which Doppler ultrasound is not conclusive. It is also useful when it is necessary to study the pelvic venous circulation, in recurrent varicose veins or in the accurate diagnosis of deep vein thrombosis. Likewise, it allows assessing the functioning of the deep veins of the leg, identifying a vein for coronary bypass grafting and in the study of anomalies or congenital defects of the venous system.