| Pulmonary thromboendarterectomy | |
|---|---|
 PTE specimen | |
| Other names | Pulmonary endarterectomy |
| Specialty | cardiothoracic surgery |
| ICD-9-CM | 38.15 |
In thoracic surgery, a pulmonary thromboendarterectomy (PTE), also referred to as pulmonary endarterectomy (PEA), [1] is an operation that removes organized clotted blood (thrombus) from the pulmonary arteries, which supply blood to the lungs.[ citation needed ]
Surgery is indicated in patients with pulmonary artery emboli that are surgically accessible. Thrombi are usually the cause of recurrent/chronic pulmonary emboli and therefore of chronic thromboembolic pulmonary hypertension (CTEPH). [2] PTE is the only definitive treatment option available for CTEPH. [3]
Due to the nature of the procedure, patients with significant hemodynamic or ventilation complications or impairments may be unable to undergo PTE.
A PTE has significant risk; mortality for the operation is typically 5%, but less in centers with high volume and experience. Individuals with favorable hemodynamic risk profiles also demonstrate lower mortality rates (1.3%). [3] PTEs are risky because of the nature of the procedure. PTEs involve a full cardiopulmonary bypass (CPB), deep hypothermia and cardioplegia (a crystalline fluid which stops the heart from beating). Actual removal of the embolus is carried out in a standstill operation (deep hypothermia and periods of cessation of circulation). [4]
There are a number of reasons why these high-risk elements of the procedure are necessary. CPB is needed to divert blood from the heart and lungs and supply the body with oxygen and blood while the pulmonary vasculature is operated on. Cardioplegia is initiated as the approach to the pulmonary arteries is performed through the pericardium, a fibrous sac surrounding the heart. Furthermore, movement from the heart makes delicate work on the closely attached pulmonary arteries complex. Hypothermia is necessary as the embolus is very delicate and the risk of disruption is high, in order to appropriately visualize the clot and remove it a bloodless field is required. Clot visualization is achieved through dissection of the pulmonary arteries which is technically challenging. If possible the clot is removed in a single piece to avoid the formation of mobile emboli. In order to achieve this CPB is periodically stopped, resulting in a complete cessation of blood circulation. This is only feasible if the patient is hypothermic (cooled to 18–20 °C) as metabolism is slowed and the body can better tolerate the resulting lack of blood supply. [5] Circulatory arrest is limited to 20 minute intervals to protect brain function. Typically an experienced surgeon can perform an entire unilateral procedure in this time. After each interval of arrest circulation is continued for 10 minutes or until pulmonary venous oxygen saturation is at least 90%. [6] Bypass time is typically 345 minutes. [4]
There are emerging alternative options available that seek to limit neurologic complications resulting from hypothermia and circulatory arrest. Currently these options have not been shown to be superior to the previously described technique. They include use of moderate hypothermia, antegrade cerebral artery perfusion without total circulatory arrest, and negative pressure application to the left ventricle. [7] [8] [9]
It is important to note that acute pulmonary embolectomy is a dramatically different procedure. It's typically performed without hypothermia as the structure of the clot is different, and the emergent nature presents different operative priorities. [10] [11]
Recovery from this procedure can be complex. Thoracic surgery, CBP and cardioplegia are associated with their own complications and management challenges, as is hypothermia. Specifically, endartectomy is associated with reperfusion pulmonary edema and "pulmonary artery steal". Reperfusion pulmonary edema occurs in up to 30% of patients and is a result of changes in permeability to the vascular endothelium. Management of this condition may require the use of supportive ventilation including BiPAP (bidirectional positive airway pressure) and fluid management with diuretics. In patients who are non responsive to this management extra corporeal circulation may be indicated. Each of these strategies are complex and require careful consideration of patient physiology. [12]
Pulmonary artery steal occurs in 70% of patients. It is related to changes in blood flow over areas of pulmonary vasculature that have been newly exposed from the endarectomy. The result is insufficient oxygenation though the mechanism causing this remains obscure. Treatment is supportive with oxygen, and ventilation, and the condition is typically self limiting. [13] [14]
The benefits of PTEs are significant. Most patients after surgery no longer suffer from shortness of breath and therefore have a much improved quality of life. Further, pulmonary vascular resistance usually drops back to close normal levels. Since the pulmonary resistance is proportional to the pressure driving the pulmonary flow (), it follows that the pulmonary pressure decreases. This in turn means that the work per time (power) decreases because it is equal to the pressure gradient times the volumetric flow, which in this case is the cardiac output. As a result of the operation, patients are spared from pulmonary hypertension and further right ventricular hypertrophy. Most pleasing is that patients who previously had right heart dysfunction often recover function. [15]
As of 2008, the UCSD Medical Center's cardiothoracic surgery department, led by Stuart W. Jamieson, was widely recognized as a pioneer in the relatively new surgery, having performed more PTEs than the rest of the world combined (over 3000 since 1970 out of a total of 4500 worldwide) with the lowest mortality rate. [16]
In the UK, PTE is offered only at one centre, [17] Royal Papworth Hospital, [18] led by surgeon Mr David Jenkins. [19] He is one of just four surgeons in the UK qualified to perform pulmonary endarterectomy surgery, all based at Royal Papworth, which is one of the most active centres in the world for this operation with approximately 190 operations performed each year and a total caseload since 1996 of more than 2,000. [20]
The operation features in a BBC Two documentary called 'Surgeons: At the Edge of Life', broadcast on Tuesday 6 October 2020. [21] The footage shows the patient's entire body being drained of blood and cooled to 20 degrees Celsius – half the normal temperature – in order to enable the surgery to occur.
 | This section needs additional citations for verification .(August 2020) |
PTEs and pulmonary thrombectomies are both operations that removed thrombus from the lung's arterial vasculature. Aside from this similarity they differ in many ways.
Veins are blood vessels in humans, and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart.
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing in, and coughing up blood. Symptoms of a blood clot in the leg may also be present, such as a red, warm, swollen, and painful leg. Signs of a PE include low blood oxygen levels, rapid breathing, rapid heart rate, and sometimes a mild fever. Severe cases can lead to passing out, abnormally low blood pressure, obstructive shock, and sudden death.
Cardiopulmonary bypass (CPB) is a technique in which a machine temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and the oxygen content of the patient's body. The CPB pump itself is often referred to as a heart–lung machine or "the pump". Cardiopulmonary bypass pumps are operated by perfusionists. CPB is a form of extracorporeal circulation. Extracorporeal membrane oxygenation is generally used for longer-term treatment.
Pulmonary hypertension is a condition of increased blood pressure in the arteries of the lungs. Symptoms include shortness of breath, fainting, tiredness, chest pain, swelling of the legs, and a fast heartbeat. The condition may make it difficult to exercise. Onset is typically gradual.
Eisenmenger's syndrome is defined as the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect causes pulmonary hypertension and eventual reversal of the shunt into a cyanotic right-to-left shunt. Because of the advent of fetal screening with echocardiography early in life, the incidence of heart defects progressing to Eisenmenger's has decreased.
Endarterectomy is a surgical procedure to remove the atheromatous plaque material, or blockage, in the lining of an artery constricted by the buildup of deposits. It is carried out by separating the plaque from the arterial wall.
In human anatomy, the bronchial arteries supply the lungs with nutrition and oxygenated blood. Although there is much variation, there are usually two bronchial arteries that run to the left lung, and one to the right lung and are a vital part of the respiratory system.
Arterial switch operation (ASO) or arterial switch, is an open heart surgical procedure used to correct dextro-transposition of the great arteries (d-TGA); its development was pioneered by Canadian cardiac surgeon William Mustard and it was named for Brazilian cardiac surgeon Adib Jatene, who was the first to use it successfully. It was the first method of d-TGA repair to be attempted, but the last to be put into regular use because of technological limitations at the time of its conception.
A pulmonary thrombectomy is an emergency surgical procedure used to remove blood clots from the pulmonary arteries.
Cardioplegia is intentional and temporary cessation of cardiac activity, primarily for cardiac surgery.
The Dor procedure is a medical technique used as part of heart surgery and originally introduced by the French cardiac surgeon Vincent Dor (b.1932). It is also known as endoventricular circular patch plasty (EVCPP).
Deep hypothermic circulatory arrest (DHCA) is a surgical technique that induces deep medical hypothermia. It involves cooling the body to temperatures between 20 °C (68 °F) to 25 °C (77 °F), and stopping blood circulation and brain function for up to one hour. It is used when blood circulation to the brain must be stopped because of delicate surgery within the brain, or because of surgery on large blood vessels that lead to or from the brain. DHCA is used to provide a better visual field during surgery due to the cessation of blood flow. DHCA is a form of carefully managed clinical death in which heartbeat and all brain activity cease.
Atrial septostomy is a surgical procedure in which a small hole is created between the upper two chambers of the heart, the atria. This procedure is primarily used to palliate dextro-Transposition of the great arteries or d-TGA, a life-threatening cyanotic congenital heart defect seen in infants. It is performed prior to an arterial switch operation. Atrial septostomy has also seen limited use as a surgical treatment for pulmonary hypertension. The first atrial septostomy was developed by Vivien Thomas in a canine model and performed in humans by Alfred Blalock. The Rashkind balloon procedure, a common atrial septostomy technique, was developed in 1966 by American cardiologist William Rashkind at the Children's Hospital of Philadelphia.
The bidirectional Glenn (BDG) shunt, or bidirectional cavopulmonary anastomosis, is a surgical technique used in pediatric cardiac surgery procedure used to temporarily improve blood oxygenation for patients with a congenital cardiac defect resulting in a single functional ventricle. Creation of a bidirectional shunt reduces the amount of blood volume that the heart needs to pump at the time of surgical repair with the Fontan procedure.
Embolectomy is the emergency surgical removal of emboli which are blocking blood circulation. It usually involves removal of thrombi, and is then referred to as thrombectomy. Embolectomy is an emergency procedure often as the last resort because permanent occlusion of a significant blood flow to an organ leads to necrosis. Other involved therapeutic options are anticoagulation and thrombolysis.
Hans-Joachim Schäfers is a German surgeon, as well as cardiac, thoracic, and vascular surgeon and university professor. He is director of the department of Thoracic and Cardiovascular Surgery at the Saarland University Medical Center in Homburg/Saar, Germany. He is known for his activities in aortic valve repair, aortic surgery, and pulmonary endarterectomy.
Chronic thromboembolic pulmonary hypertension (CTEPH) is a long-term disease caused by a blockage in the blood vessels that deliver blood from the heart to the lungs. These blockages cause increased resistance to flow in the pulmonary arterial tree which in turn leads to rise in pressure in these arteries. The blockages either result from organised blood clots that usually originate from the deep veins of the lower limbs of the body (thromboembolism) and lodge in the pulmonary arterial tree after passing through the right side of the heart. The blockages may also result from scar tissue that forms at the site where the clot has damaged the endothelial lining of the pulmonary arteries, causing permanent fibrous obstruction. Most patients have a combination of microvascular and macrovascular obstruction. Some patients may present with normal or near-normal pulmonary pressures at rest despite symptomatic disease. These patients are labelled as having chronic thromboembolic disease (CTED).
Stuart William Jamieson is a British cardiothoracic surgeon, specialising in pulmonary thromboendarterectomy (PTE), a surgical procedure performed to remove organized clotted blood (thrombus) from pulmonary arteries in people with chronic thromboembolic pulmonary hypertension (CTEPH).
Balloon pulmonary angioplasty (BPA) is an emerging minimally invasive procedure to treat chronic thromboembolic pulmonary hypertension (CTEPH) in people who are not suitable for pulmonary thromboendarterectomy (PTE) or still have residual pulmonary hypertension and areas of narrowing in the pulmonary arterial tree following previous PTE.
Popliteal bypass surgery, more commonly known as femoropopliteal bypass or more generally as lower extremity bypass surgery, is a surgical procedure used to treat diseased leg arteries above or below the knee. It is used as a medical intervention to salvage limbs that are at risk of amputation and to improve walking ability in people with severe intermittent claudication and ischemic rest pain.
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