Pulmonary Endarterectomy

Overview

Patients with an acute pulmonary embolism (PE) may develop chronic thromboembolic pulmonary hypertension (CTEPH). In CTEPH, it is thought that scar tissue from the initial PE site builds in the lungs and impedes the bloodstream, resulting in pulmonary hypertension and shortness of breath. Patients with CTEPH may have very limited everyday functioning when they are first present. About 75 percent of CTEPH patients will mention having an acute PE in the past, frequently many years ago. In the United States, there are about 600,000 cases of PE each year, and up to 4% of individuals may develop CTEPH. This disorder is underdiagnosed. You don't want to ignore this diagnosis because it's the only type of pulmonary hypertension that may be treated among all the causes of pulmonary embolism. Unfortunately, it frequently goes undiagnosed. If you think a patient has CTEPH, you should refer them to a pulmonary vascular disease treatment facility for additional assessment.

 

What is Pulmonary Endarterectomy?

Pulmonary endarterectomy, or PEA for short, is an operation to remove blood clots from the pulmonary arteries in the lungs. Most persons with pulmonary hypertension (PH) do not have obstructions caused by blood clots. Some PH patients can have obstructions that are not operable with pulmonary endarterectomy.

 

Pulmonary Endarterectomy Benefits

The only treatment for chronic thromboembolic pulmonary hypertension (CTEPH) is PTE. In the majority of patients, the operation is effective, resulting in better breathing, lung function, and capacity to be active. Most patients who were on oxygen before surgery can stop using it thereafter, and disease-related damage to their right heart is frequently reversed. After surgery, long-term survival is very good.

 

Pulmonary Endarterectomy Indications

Patients with chronic thromboembolic pulmonary hypertension (CTEPH) frequently exhibit dyspnea when they exert themselves. In many of these individuals, a history of previous symptomatic pulmonary embolism is difficult to document. Without that history, making a diagnosis can be challenging and frequently takes a while. But it happens frequently that a patient will have a history of having experienced a sizable pulmonary embolus. Usually, the therapy for that incident was completely appropriate. Other patients may claim that the treatment was ineffective or that the diagnosis was not established until a few months after the acute incidence.

Patients eventually develop the signs and symptoms of right heart failure after progressing to hypoxemia. When that happens, they might exhibit ascites or lower extremities edema. This is unmistakably a sign of the disease progressing. Recurrent pulmonary emboli were traditionally thought to be the cause of this progression. Although this is undoubtedly possible, some of these individuals will continue to improve while using the proper anticoagulant and vena cava filters. The pulmonary arteries appear to experience a secondary fibroproliferative response, which progresses to produce more distant obstructions.

Younger patients could be generally asymptomatic at rest but experience severe breathlessness after modest exertion. The existence of a permanent obstruction and the absence of a typical response to exercise explain this. Angina can be a symptom in patients with coronary disease. Instead, even in the absence of substantial coronary blockages, increased right heart strain can cause angina. If thoroughly questioned, the majority of patients will report a history of dizziness or potential syncope. This happens more frequently after coughing or doing other actions that cause a Valsalva and a brief rise in pulmonary vascular resistance.

Once the diagnosis has been made, the right individuals can be chosen for surgical intervention. Candidates for surgery must have severe hemodynamic and cardiovascular dysfunction as well as pulmonary vascular obstruction. At rest or after activity, there should be at least 300 dynes/sec/cm-5 of pulmonary vascular resistance. Additionally, the thrombi must be accessible for surgery. Finding the right patients has been made easier with the establishment of a classification system for anatomic distribution. There is a clear central thrombus in type I disease. Type II disease is characterized by intimal thickening and webs at the primary lobar and segmental levels rather than major vessel thrombus. A disease that only affects the segmental and subsegmental levels is referred to as Type III. Finally, type IV disease is non-operable and only affects relatively peripheral resistance vessels. Endarterectomy is quite effective in treating type I and type II disorders, but type III diseases should only be handled by a surgeon with pulmonary endarterectomy competence.

The 5-year survival rate drops to 30% after mean pulmonary artery (PA) pressures approach 30 mm Hg. Only 10% of people survive for five years after that pressure reaches 50 mm Hg. Most of the individuals we've taken care of had mean PA pressures that were close to 50 mm Hg on average. That would mean a 90% chance of passing away within the next five years. The current perioperative survival rate of >95% justifies the risks and involved nature of this surgical procedure, and most patients find it to be fairly acceptable.

 

Pulmonary Endarterectomy Contraindications

Patients with type IV disease shouldn't have endarterectomy surgery, as was already mentioned. Additionally, endarterectomy candidates should have few coexisting conditions. Significant parenchymal lung disease increases the risk of perioperative mortality, limited improvement in dyspnea, and prolonged postoperative mechanical ventilation. A disease of the peripheral arteries is another significant relative contraindication. Establishing a rapid and prompt diuresis and managing postoperative fluids are difficult conditions caused by chronic renal failure. People who have impaired renal function typically do worse. One should be extremely picky when evaluating patients who are 80 years old or older.

Patients must lastly understand and accept the hazards associated with surgery. Operating on patients who have advanced right heart failure and experiencing circulatory arrest comes with additional risks on top of open-heart surgery's usual problems. As a result, a significant amount of time is spent educating patients and their families about the specifics of the procedure, the anticipated postoperative course, and any potential complications. Once the patient has been informed of the disease's natural course, they generally express great enthusiasm for surgical intervention.

 

Assessment Before Pulmonary Endarterectomy

Without care, the examination may easily end up being redundant or improperly directed. As a result, it's crucial to arrange the knowledge that already exists and to allocate new research projects with three precise objectives in mind. The first two objectives are typically determined during the diagnostic evaluation, which frequently starts before the patient even arrives at the surgery center. The surgeon's responsibility is to assess surgical candidacy and operability. The diagnostic techniques mentioned below have evolved into most doctor practice:

 

Pulmonary Function Test (PFT)

One must be able to identify the pattern of abnormalities, which is more crucial than recording any particular numbers or threshold values. Particularly, the symptoms and abnormalities in gas exchange outweigh any spirometric defects by a significant margin. When a patient experiences pronounced dyspnea, the diffusion capacity frequently decreases significantly. There are often smaller obstructive or restrictive abnormalities, though. In contrast, patients with CTEPH may have additional parenchymal lung conditions that make surgery riskier or completely contraindicated.

 

Arterial Blood Gases (ABGs)

On blood gas analyses, the PO2 is frequently low. Exercise may cause a sharp decline if this is not the case at rest. This is caused, at least in part, by patients' failure to adequately increase their cardiac output with exercise due to pulmonary blood flow blockages that are fixed. Their mixed venous oxygen content decreases as they work out because they take in more oxygen. Progressive hypoxemia results because insufficient cardiac output while passing through a functional lung limits reoxygenation. Furthermore, a patent foramen ovale may be present in up to 25% of these patients. Exercise reduces systemic vascular resistance and causes a quick increase in right heart and PA pressures. Any hypoxemia will be made worse by the atrial level right to left shunt that results.

 

Echocardiography

In addition to screening for any coexisting heart pathology, echocardiography gives an estimate of pulmonary pressures. Atrial and ventricular septae may be pushed from right to left, and right atrial and ventricular hypertrophy are frequently evident. 25% of these patients have a patent foramen ovale, however, an agitated saline contrast test may be necessary to find it. Typically, tricuspid regurgitation ranges from mild to severe. The primary objective of the diagnostic examination is effectively met once the echocardiography has shown that pulmonary hypertension is present. The etiology must then be established.

 

Ventilation-Perfusion (VQ) Scan

VQ scanning frequently reveals segmental or more significant mismatched defects. Patchy or subsegmental defects are possible in primary pulmonary hypertension, although the scan could be completely normal. As a result, the difference between small resistance vascular disease and chronic thromboembolic pulmonary hypertension can be more clearly distinguished. Unfortunately, the level of central blockage is frequently overestimated by VQ scanning. Although recanalized vessels may provide hemodynamical flow resistance, isotopes can still approach the periphery. Scan results may appear falsely normal as a result. Additionally, VQ scanning is unable to clearly show the extent of the diseased artery wall thickening or its exact position or proximal extent. Therefore, choosing a patient for surgery only based on VQ scanning is improper. However, VQ scanning is employed as a screening test to identify whether individuals should be properly referred for more invasive tests.

 

Pulmonary Endarterectomy Preparation

If you need to fast or avoid taking any medications, your healthcare professional will inform you of this as well as other preparations you need to make for your procedure. Follow the recommendations of your healthcare provider for:

• Medications. People frequently quit taking nonsteroidal anti-inflammatory drugs (NSAIDs) and blood thinners such as aspirin, warfarin, or other medications that prevent blood clots and strokes. These medications may make bleeding more probable.
• Food and drink. Before your procedure, you could be asked to fast (avoid eating or drinking). It is safer to undergo anesthesia on an empty stomach.
• Alcohol and smoking. Limit alcohol consumption and stop smoking. Both can delay post-operative recovery and raise the possibility of complications.

 

Pulmonary Endarterectomy Procedure

The surgery, which typically begins early in the morning and lasts for around six hours, is done while you are under anesthetic. Your surgical staff will:

• Allows you to breathe by placing an endotracheal tube (ETT) through your mouth or nose and connecting it to a ventilator to provide oxygen.
• Cuts your sternum, or breastbone, to access your heart and lungs.
• Attaches you to a cardiopulmonary bypass system, which mimics the function of your heart and lungs.
• Cools your body slowly to 18 degrees Celsius.
• Removes blockages and scar tissue from your arteries using specialized tools.
• brings your body temperature back to normal, disconnects you from the bypass machine, and leaves you properly connected to the ventilator.
• Closes your chest, leaving tubes for your body's extra fluid to be drained.

 

What Happens After Pulmonary Endarterectomy?

You will spend the night in the intensive care unit (ICU) following PTE. Your medical team will perform a breathing test on you the following morning. They'll turn off the ventilator if you can breathe on your own. Typically, you spend seven to ten days in the hospital. As soon as possible, frequently the day after surgery, you shift from the ICU to an intermediate level of care to begin your recovery. Recovery is similar to that following open heart surgery. Within a few days, you might start walking, then gradually add other activities. Additionally, you'll have a few tests, including one to determine how much oxygen you'll require once you return home.

Over time, you can resume your normal activities. But for at least six weeks following surgery, you are not permitted to drive, work, or lift anything greater than 10 pounds. You are allowed to lift up to 25 pounds between weeks seven and twelve. There are no limits after the first 12 weeks. You can often resume your normal activities three months after surgery. Following surgery, your breathing and capacity for the activity should improve and may do so for up to four years.

 

Pulmonary Endarterectomy Complications

The risk of PTE has significantly dropped over the past year, and for the majority of patients, the chance of dying during surgery is currently less than 1%. Stroke risk ranges from 1% to 2%.

Some people will continue to experience some degree of recurrent pulmonary hypertension (PH) after PTE, which may necessitate medication.

After surgery, pericardial effusion, a fluid buildup around the heart, can occasionally occur. You might encounter:

• Chest pain
• Fainting.
• Sudden respiratory problems or shortness of breath.

 

Conclusion

Given its outstanding long-term results and the fact that improvements in surgical procedures are allowing for a more precise assessment of operability and better results, PEA is the treatment for CTEPH that is indicated by guidelines. As a result, many patients with more severe disease or higher surgical risk who were previously considered inoperable can now be treated successfully at specialized institutions. Despite these advancements, some patients will still be unsuitable for PEA, while others will experience recurrent or persistent PH even after surgery. Therefore, all patients must receive long-term follow-ups following PEA. Multimodal therapy using PEA, balloon pulmonary angioplasty, and/or medical therapy is probably going to be a popular therapeutic choice in the future for a lot of patients.