WHAT you can?t see and feel won?t hurt you, right? This may not be entirely true if we are talking about deep vein thrombosis (DVT) or the formation of blood clot in one of the large veins, usually in the lower limbs.

Having DVT, which could occur after surgery or during flight (especially if the air traveler does not move his or her legs regularly), is not life threatening.

But while it could block blood flow, causing swelling, discomfort, redness, or warmth in one?s legs. In many cases, DVT exhibits no initial symptoms.

?This is potentially dangerous because if this blood clot breaks loose from the wall of the vein and travels to the lungs?a condition known as venous thromboembolism?it could block a pulmonary artery or one of its branches,? warned Dr. Teresa B. Abola, a cardiologist at the Philippine Heart Center.

During the recent 2nd VTE Free Day celebration, Abola explained that this condition called pulmonary embolism could cause chest pain, shortness of breath and possibly coughing up of blood.

Obstruct circulation

?A large clot in the lungs may obstruct blood circulation, causing breathlessness, dizziness or shock, which may be life threatening,? Abola explained.

The usual way to detect DVT is through venous duplex scan, a highly accurate means that uses sound waves to check how well the veins are returning blood to the heart.

Once the suspicion is confirmed, an anticoagulant is usually given to stop blood clots from forming.

For years, the standard treatment has been a medication called heparin. However, if heparin is given continuously, one must stay in the hospital as the drug is administered through the vein (intravenously).

Through injection

To solve this inconvenience, enoxaparin (Clexane) was developed, a new form of heparin that could now be given by injection once a day.

In fact sanofi-aventis, its manufacturer, has announced that the drug demonstrated a significant 43 percent reduction in VTE events with enoxaparin versus unfractionated heparin in medically-ill patients who suffered an acute ischemic stroke.

Abola said those who could benefit from these type of drug include those with hip or lower leg fracture, hip or knee operation, major operation, trauma and spinal cord injury.

Those with moderate risk factor for VTE include those patients operated on central venous lines, who underwent chemotherapy, who had congestive heart failure, are undergoing hormone replacement therapy, are taking oral contraceptive pills, paralytic stroke patients, during childbirth, cancer patients and those with medical history of VTE.