The incidence of pulmonary thromboembolism (PTE) in the elderly is increasing year by year. Some reports show that the in-hospital mortality rate of elderly PTE patients >65 years old is 3-10 times higher than that of younger patients, seriously endangering the health of the elderly.
Pathogenesis
Firstly, the elasticity of blood vessel wall is reduced in the elderly, the intima-media plaque is formed and detached, and the blood flow is slow.
Secondly, the elderly are often combined with various underlying diseases, such as diabetes, coronary atherosclerotic heart disease (coronary heart disease), malignant tumors, hyperlipidemia, etc., which can lead to an increase in blood viscosity.
Thirdly, the elderly have less activity and spend more time sitting or lying in bed, all of which can contribute to the formation of venous thrombosis.
High-risk factors
The vast majority of patients with PTE have high-risk factors, with only 6% not finding a cause. For the elderly, the following are high-risk factors for PTE.
Thrombophlebitis and deep vein thrombosis (DVT) are the main causes of PTE. 60-85% of emboli originate from lower limb veins and pelvic veins.
Cardiopulmonary disease is most common in atrial fibrillation, heart failure combined with rheumatic heart disease, coronary heart disease, pulmonary heart disease (pulmonary heart disease) is also prone to combined PTE, right atrial (ventricular) appendage thrombus detachment can cause PTE.
Tumors of the lung, pancreas, gastrointestinal tract and reproductive system are likely to be combined with metastatic tumor thrombosis, or tumors causing hypercoagulability resulting in thrombus obstruction of the pulmonary artery, among which lung cancer is the most common.
Other long-term bed rest, obesity, fracture, post-joint replacement, and post-surgery (especially abdominal surgery).
Clinical features
The clinical features of PTE in the elderly are diverse and lack specificity. Because of the slow response and atypical presentation, it often leads to misdiagnosis and omission. Common symptoms in elderly patients with PTE include dyspnea after activity, chest pain (mostly pleuritic pain, a few angina attacks), hemoptysis, cough, sputum, and syncope. Dyspnea is the most common symptom in elderly PTE patients, and syncope occurs much more frequently in elderly PTE patients than in young people.
Many elderly patients with PTE also present with nonspecific symptoms, including persistent low-grade fever, changes in mental status, and no respiratory symptoms or similar manifestations of respiratory infection. Common clinical manifestations include fever, faster breathing, increased heart rate (>100 beats/min), sudden onset of atrial fibrillation, and audible rales, wet sounds and pleural friction sounds in the lungs. hyper P2, and systolic murmurs can be heard in the second intercostal space on the left edge of the sternum. Swelling, tenderness, stiffness, hyperpigmentation and superficial varicose veins due to jugular venous filling and pulsation and deep vein thrombosis in the lower extremities.
Ancillary tests
Laboratory tests
Laboratory tests include arterial blood gas analysis, plasma D-dimer, cardiac troponin, brain natriuretic peptide, etc. Cardiac troponin levels are significantly elevated in approximately 11% to 50% of patients with acute PTE and can be used as an independent indicator for risk stratification and prognostic assessment of patients with acute PTE. Brain natriuretic peptide levels are valuable in determining right ventricular function in patients with acute PTE.
Imaging examinations
Chest radiographs are less sensitive and less specific, but they are valuable for evaluating the cardiopulmonary condition and differential diagnosis (e.g., pneumonia) in elderly patients.
ECG is a “double-edged sword”, especially in elderly patients with coronary artery disease and pulmonary artery disease. It is important to carefully observe the dynamic changes of ECG and closely combine them with clinical manifestations to avoid misdiagnosis or missed diagnosis and to improve the value of ECG in diagnosing PTE.
Echocardiography is used to observe the pulmonary artery and heart condition of PTE patients through direct signs and indirect signs. It also differentiates from diseases such as myocardial infarction and infective endocarditis.
Lower extremity deep vein examination 50%~80% of PTE patients have lower extremity deep vein thrombosis (DVT), and the prevalence of DVT is significantly higher in the elderly than in the non-elderly, and is closely related to PTE. Therefore, it is meaningful to perform lower extremity DVT ultrasonography in older adults with suspected PTE.
Lung Perfusion and Ventilation Scans Lung perfusion/ventilation scans have limitations in the diagnosis of PTE in the elderly. Pulmonary perfusion/ventilation scans may be considered only in patients with iodine allergy or impaired renal function.
Spiral CT pulmonary arteriography (CTPA) is important in the diagnosis of PTE in the elderly. Due to the potential damage of the contrast agent iodine to the kidneys, CTPA is not recommended in elderly patients with poor renal function, especially those with creatinine clearance <30 ml/min, and can be replaced by pulmonary perfusion/ventilation scans.
Magnetic resonance imaging (MRI) of the pulmonary arteries its similar to angiography and can show thrombus within the 4th level branches of the pulmonary arteries. However, its scan time is long, elderly patients with PTE cannot fully cooperate with it, and it is expensive, and its diagnostic significance is not significantly different compared with CTPA, so it is not used much at present.
Pulmonary arteriography has been the gold standard for the diagnosis of PTE and has high sensitivity and specificity for the diagnosis of PTE. It should only be considered when there is a high clinical suspicion of PTE and venous ultrasound and CTPA are negative, or when interventional debulking or surgical retrieval is required.
Treatment strategy for PTE in the elderly
The principles of treatment are to overcome the critical phase, reduce or eliminate the thrombus, relieve the cardiopulmonary dysfunction caused by embolism and prevent the recurrence of PTE.
Anticoagulation therapy
Although it cannot directly promote thrombus lysis and reduce deep vein thrombosis, it can prevent further occurrence and development of thrombus, and reduce the incidence of fatal PTE by 60%-70%, and significantly reduce recurrent thromboembolic events.
The aim of initial anticoagulation therapy is to reduce death and recurrent embolic events. Intravenous plain heparin, subcutaneous low molecular weight heparin or sodium fondaparinux are used. Fondaparinux sodium is mainly excreted by the kidneys and should be used with caution in elderly patients with renal insufficiency.
The purpose of long-term anticoagulation therapy is to prevent lethal and non-lethal venous thromboembolic events and to prevent recurrence of thrombosis. The main drug currently used for long-term anticoagulation is warfarin. The general course of anticoagulation therapy is at least 3 to 6 months to maintain the international normalized ratio (INR) between 2 and 3. Close observation is required during anticoagulation to detect early signs of bleeding and treat them promptly; monitor coagulation indicators to reduce bleeding complications.
Thrombolytic therapy
Patients with high-risk PTE should be treated with immediate initial anticoagulation with heparin, followed by thrombolytic therapy. Current thrombolytic drugs include streptokinase, urokinase, and recombinant tissue-type fibrinogen kinase (rt-PA). The efficiency of thrombolytic therapy has been reported to be similar in elderly patients with PTE (>70 years) and non-elderly patients with PTE (<70 years), and no increased risk of major organ bleeding complications has been observed. Therefore, a comprehensive clinical assessment of elderly patients with PTE should be performed to weigh the benefits of thrombolytic therapy against the possible risk of bleeding and to develop an individualized treatment plan.
Interventional therapy
In elderly patients with PTE or deep vein thromboembolism who are unable to receive anticoagulation because of contraindications, an inferior vena cava filter can be placed through a catheter with the aim of intercepting large thromboemboli before they enter the pulmonary circulation, thus preventing recurrence. Interventional therapy is invasive and should be weighed against the advantages and disadvantages in elderly patients. Subcatheter fragmentation versus local thrombolysis should be chosen carefully.
Surgical treatment
In view of the progress of medical treatment and the high morbidity and mortality rate of surgical treatment, which is not easily tolerated by elderly patients, pulmonary artery embolization is currently considered only in the following cases: life-threatening embolism of the main pulmonary artery or left and right pulmonary arteries in the short term; failure of thrombolytic therapy; and contraindication to thrombolytic therapy.
Prevention of PTE in the elderly
Avoid inputting drugs that irritate the vein wall, remove deep vein catheter as early as possible, and actively treat varicose veins. Those who are bedridden for a long time should be encouraged to do active activities and coughing movements of lower limbs in bed, wear long elastic stockings or use intermittent inflatable compression pumps for lower limbs, and encourage early bedtime activities.
Active treatment of hypercoagulable state and lower limb deep vein thrombosis; patients with peripheral deep vein thrombosis should especially keep bowel movement smooth; correction of atrial fibrillation and other susceptible diseases.
It should be noted that mechanical prevention of lower extremity DVT dislodgement, such as vena cava filters, should be applied with caution and, if necessary, temporary filters are recommended with proper use and optimal compliance, mainly in patients at high risk of bleeding, at risk of fatal recurrent PTE or as an adjunct to anticoagulation.