WHAT IS A PULMONARY EMBOLISM?
A PE is when a blood clot travels up the vein system, travels through the right side of the heart and ends up in the lungs. Contrary to popular belief, the problem occurs when it lodges in the veins leading into the lungs, rather than ending up in the heart. This process causes decreased oxygen to enter into the body and a potentially fatal situation.
WHAT ARE THE SIGNS AND SYMPTOMS OF A PE?
PE can occur without any signs or symptoms. In these cases the amount of clot burden was small, or the lung function was adequate to handle the clot load, and the patient remained asymptomatic. The classical symptoms of pulmonary embolism are sudden onset of chest pain, usually described as sharp and stabbing. Other symptoms can include chest wall tenderness, back pain or shoulder pain. Coughing up blood and pain on inspiration can also occur. Sometimes, there might be a change in the heart rhythm.
Physical examination findings may include low blood pressure, fast breathing, or chest wall tenderness. The physical examination is often initially not impressive. For that reason, a high index of suspicion is indicated to make the diagnosis and initiate treatment. Patients with an undiagnosed pulmonary embolism who remain untreated have a very high incidence of recurrent PE and death.
HOW IS A PULMONARY EMBOLUS DIAGNOSED?
Pulmonary emboli are diagnosed by having a high index of suspicion. That means if any concerns suggest a PE, then diagnostic testing should be undertaken. The diagnostic test of choice at this time is a CT scan of the chest with I.V. contrast. The pulmonary embolism can be seen as a dark spot in the veins of the lungs. More invasive evaluation can be performed with angiography if there are any doubts from the CT scan, or if a more aggressive approach to intervention is required.
CT scan showing several areas of PE WHAT IS THE TREATMENT FOR PE?
Most cases of pulmonary embolism are not fatal and the crux of the treatment is to prevent further emboli from breaking off and ending up in the lungs. Again, the importance of thinking about the diagnosis of PE is of paramount importance, because initially the symptoms might not be specific, and can be quite vague. Once the suspicion is raised, and diagnostic testing with a CT scan confirms the presence of a pulmonary embolism, then the next step is to make sure the patient is stable, and plan intervention. In most cases, the intervention is thinning out the blood with medication, Lovenox initially, then Warfarin. The PE has also done the damage it can to the lungs, and the point of thinning out the blood is to prevent further PEs from occurring while the body heals.
Some patients cannot tolerate blood thinning for medical reasons such as recent surgery, an active and bleeding stomach ulcer, or the elderly and infirm who are at high risk for falling and injury or bleeding from another source. In these situations, the alternative treatment is to place a device in the main vein that drains both legs to prevent further blood clots from travelling up into the lungs. This device is called an inferior vena cava (IVC) filter. It is placed under X-ray guidance under the kidney veins in the vena cava. It is guided to this site through the groin or neck veins, depending on the patient’s anatomy. There are numerous types of IVC filter, and they are very well tolerated.
MORE AGGRESSIVE APPROACHES TO PE
If the patient is in serious condition and is clinically doing poorly, there are more aggressive approaches to treating the pulmonary embolism, based on trying to remove or dissolve the clot. One such option is to mechanically remove the clot using a device that suctions out the thrombus and infiltrates it with clot-dissolving medication. There are other mechanical methods of removing the clots with novel devices. These methods are not very invasive and performed using a small puncture in the veins of the groin to access the circulation and enter the lung veins to try and extract the clot. This process of removing or dissolving clots is termed venous thrombolysis.
Surgical intervention is the most aggressive approach which involves opening the chest cavity and trying to remove the clot. This latter approach has a high mortality rate and is not used very often with the advent of catheter-based techniques as discussed previously.