We call pulmonary thromboembolism to the cardiovascular event that results from a clot that travels in the blood vessels and lodges in any part of the pulmonary artery. The obstruction can be either complete or incomplete, and in cases of complete obstruction it is referred to as massive pulmonary embolism.
In this article, we will walk you through the therapeutic choices your doctor will possibly consider when treating a case of pulmonary thromboembolism. Treatment for special conditions such as pregnancy-related thromboembolism, home treatment measures, and cancer-related thromboembolism will not be covered in this article.
A brief overlook on the treatment of pulmonary thromboembolism
The main goal of treating pulmonary thromboembolism is avoiding a life-threatening outcome by stopping the formation of blood clots and the progression of the disease. This reduces the chances of new episodes after the acute cardiovascular event that would increase the risk of death due to pulmonary thromboembolism. Another goal is to prevent the progression of pulmonary thromboembolism to chronic venous insufficiency, pulmonary hypertension, and other complications.
To achieve these goals, your doctor will likely follow these steps:
1. Treating your risk factors
There are risk factors for blood clot formation that can be addressed to reduce the incidence and complications of pulmonary embolism. For instance, your doctor might take out certain medications that will contribute to clot formation, such as oral contraceptives and vitamin K. Another measure will be controlling your weight, reducing the time you spent sitting, lying down or immobilized, lowering your blood pressure in cases of hypertension, and advising against tobacco use. In some cases, your doctor might notice a blood imbalance of a substance called homocysteine. When it’s elevated, he will prescribe folic acid with or without vitamin B6.
2. Early deambulation
It means walking or moving around closely after being treated for a pulmonary embolism. It is recommended in most cases unless the patient has a case of massive pulmonary thromboembolism with a large blood clot or several blood clots compromising various parts of the vascular network. It is also not recommended in cases of unstable blood clots and hypotension. Early deambulation or walking is recommended 5 to 7 days after starting treatment with anticoagulants.
It is a potent anticoagulant administered subcutaneously or in intravenous solutions with strict control of laboratory parameters. Your doctor will order several exams and keep ordering them as you go through heparin treatment, which is why it requires to be hospitalized in order to be administered. This drug inactivates the enzymes and blood factors that trigger blood clotting, and the type of heparin that is advised for pulmonary thromboembolism is low molecular weight heparin, which is equally effective as another group called unfractionated heparin. Doses are calculated considering the patient’s weight, and it is administered every 12 hours along with oral anticoagulants for 5 days or more.
A word of caution about heparin use
Heparin use should be closely monitored in a hospitalized patient. There are several side effects we should avoid, such as:
A reduction in platelet levels
Platelet count is one of the most critical parameters to monitor in patients under heparin. At certain doses, this drug might compromise the normal formation of platelets and lead to a clinical entity called heparin-induced thrombocytopenia.
High levels of potassium
Heparin is capable of inducing suppression of a hormone called aldosterone, and leads to hyperkalemia (high levels of potassium) that in turn affect our cardiovascular function.
This is more likely in patients who require heparin treatment for 10 days or more, especially in older adults.
Hepatic function imbalances
Hepatic enzymes should be closely monitored to detect a sudden rise in levels of ALT and AST.
In some patients, heparin of low molecular weight should not be administered or require an individual adjustment of their doses. This is the case of patients with renal failure, renal transplants, patients with obesity and pregnant women in their last few months of pregnancy.
Using heparin is contraindicated in case of pulmonary thromboembolism associated with hypotension or alterations in the right ventricle of the heart.
In these patients, we should consider the use of unfractionated heparin, which requires more stringent monitoring of laboratory analyses, including the measurement of partial thromboplastin time (PTT) every 6 hours. Dosage adjustment is commonly required and depends on laboratory findings because the response to this drug is highly variable among individual patients.
It is imperative to remember that patients who do not reach the right dose of heparin in their anticoagulation therapy have a higher risk of pulmonary embolism relapse. On the other hand, surpassing heparin doses is only related to a relative risk of bleeding. Thus, even though it is associated with side effects and requires close monitoring, heparin use in these should not be underestimated.
Other therapeutic measures to consider in pulmonary embolism
There are two main parts of the long-term treatment in patients with a history of acute pulmonary thromboembolism. They are as follows:
Immediately after heparin therapy, your doctor will prescribe an oral anticoagulant capable of inhibiting the activation of coagulation factors in the blood. This treatment depends on the age of the patient and his current weight and should be started right after diagnosing pulmonary embolism. Lower doses will be prescribed to older patients and dosage might increase depending on your weight. Depending on your lab tests on day 3 or 4, your dose will be further adjusted and maintained alongside with heparin until it is removed from the anticoagulant protocol.
It is an exceptional measure applied to patients with a higher compromise of their pulmonary artery (massive thromboembolism), hypotension, and low bleeding risk. This procedure is meant to destroy or dissolve the blood clot, but in some patients, it might trigger an allergic reaction, which is why thrombolysis is usually accompanied with steroid drugs to modulate the immune response. Before proceeding with thrombolysis, heparin treatment is suspended, and a series of lab tests are performed before and after to prevent any complication.
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