Aneurysm Repair (TEVAR)
What is this operation?
A thoracic endovascular aneurysm repair (TEVAR) is a minimally invasive procedure to treat, and therefore prevent rupture of, a thoracic or thoracoabdominal aortic aneurysm. Typically a stent graft is passed into the aneurysmal aorta via a puncture in the groin artery. Once in the correct position, it is deployed and fixed in position. It works like the inner tubing of a tyre that effectively takes the pressure of the aneurysmal wall, reducing the likelihood of its rupture. Descending thoracic aortic aneurysms are treated with tubular stent grafts. Aneurysms involving the thoracic and abdominal aorta require custom made fenestrated or branched stent grafts that allow coverage of the aorta while preserving flow to important aortic side branches such as the renal arteries or arteries supplying the gut, liver and stomach.
Why is this operation being offered?
Endovascular aneurysm repair is a prophylactic procedure, with the aim of preventing rupture of the aneurysm - usually a fatal event. The risk of rupture of any aneurysm is related to its size; below 5cm maximum AP diameter, the risk of rupture is very small (
What happens before an operation?
Before you undergo a TEVAR a number of essential investigations and assessments are performed to assess the suitability of your aortic anatomy for endovascular repair as well as your overall fitness to undergo major arterial surgery. These may include: •Blood tests •CT angiography •Cardiac Echocardiogram •Cardiopulmonary exercise test •Chest X-ray •ECG Once the decision has been made to proceed to TEVAR, an admission date will be agreed between you and your surgeon. A pre-admission visit may be required to complete paperwork and undertake blood tests or other allied tests required prior to undergoing a general anaesthetic. Please bring all your medications to your pre-admission review.
What happens on admission?
Your surgeon will visit you and go over the planned procedure again, giving you the opportunity to ask any additional questions. You will also be visited by your anaesthetist. Please do not stop any of your normal medications unless specifically instructed to by your surgeon or anaesthetist. If you smoke we strongly encourage you to stop as soon as possible to reduce the risk of peri-operative complications.
What happens during the operation?
The majority of TEVAR cases are performed under general anaesthesia (with you asleep). Occasionally the procedure may be performed under a spinal anaesthetic, where an injection into your back numbs you from the waist down for the duration of the procedure or even under local anaesthetic. The choice of one of the three anaesthesia modalities depends on your general condition and co-morbidities as well as your own preferences. The first part of your operation involves giving you an anaesthetic. If the procedure is to be performed under general anaesthesia, a tube will be placed into your airpipe once you have been anaesthetised and connected to a mechanical ventilator that will breath for you during the procedure. Additionally, you will have a tube (catheter) inserted into your bladder to drain your urine. This facilitates accurate assessment of your hydration status during and immediately after the operation. Occasionally the anaesthetist will decide to insert a small tube into an artery in your wrist to enable accurate measurement of your blood pressure during your operation. Additionally, depending on the extent of the aortic repair, it may be decided to but a drainage tube in your spine, to protect your spinal cord against spinal cord ischaemia. Once the necessary monitoring equipment has been connected your surgeon will start the operation. At Circulation Clinic we undertake all TEVAR procedures as joint cases with two of our consultants operating together. This reduces the time taken to perform the operation and thereby the time you are under general anaesthesia. We strongly believe this improves outcomes and reduces the risk of a variety of potential complications including heart attacks, kidney failure, respiratory complications and infection rates. Through small transverse incisions the surgeons will expose the femoral artery in both groins. The femoral artery is punctured and a wire is advanced through the puncture hole into the aorta. Over this wire the stent graft components are manoeuvred into place and deployed under X-ray image guidance. In order to visualise relevant side-branches and facilitate safe positioning of the stentgraft, iodine based radiopaque contrast is injected for imaging. At the end of the procedure a completion angiogram is obtained in order to confirm successful exclusion of the aortic pathology. If medically indicated, it is possible to perform this procedure under regional block (spinal anaesthesia) or local anaesthetic. This will be decided in conjunction with the anaesthetist. The wounds are repaired in layer with stitches. A drain may be inserted into the wounds to drain any excess fluid that may accumulate in the immediate post-operative period. A chest X-ray and will be obtained the first post-operative day to assess the position of the stent graft.
What are the potential risks?
No surgery is without risk. TEVAR may be a minimally invasive (key hole) procedure, but it is associated with manipulation of the aorta and may therefore have potentially serious complications including death. Complications of surgery can broadly be categorised according to when they occur (during the hospital admission - early, or following discharge - late) and whether or not they occur at the site of surgery (local) or affect the entire body (systemic). Some possible complications of TEVAR include; •Early complications: •Local oWound related - Bleeding - Infection - Wound breakdown - Fluid collection oInjury to surrounding structures - Nerve damage causing numbness, pain or weakness in the leg - Lymphatic leak causing leakage from the wound, collection or leg swelling - Ascending aortic dissection oGraft complications: - Bleeding or blockage requiring re-operation. - Graft infection (rare) oBlood clot in leg (deep vein thrombosis) •Systemic oHeart related - Heart attack - Irregular heart rhythm oLung related - Pneumonia - Fluid on the lungs - Clot on the lung (pulmonary embolus) oKidney related - Kidney failure that may require temporary dialysis oBrain related - Stroke oSpinal cord related - Spinal cord ischemia: This is caused by exclusion of small arteries supplying the spinal cord that arise from the aorta in the chest and abdomen. Inadequate perfusion of the spinal cord leads to nerve dysfunction and potentially paraplegia. Your team assess the risk of this complication pre-operatively by taking into account factors known to contribute to spinal cord ischaemia, such as extent of stentgraft aortic coverage, and patency of pelvic (internal iliac) or left shoulder (subclavian) arteries. If you are felt to be at a high risk for this complication your surgeons may opt to insert a spinal cord drain prior to surgery to improve cord perfusion in the operative and peri-operative period. •Late complications •Stent graft blockage: oBlockage of (a limb of) the stent graft is a rare occurrence. It is seen in 0-5% of TEVAR cases. This may be precipitated by stent graft kinking or narrowing/blockages of blood vessels upstream or downstream of the stent graft. The indication for treatment depends on the severity of associated symptoms, the physical condition of the patient and the vascular anatomy. If possible, endovascular (key hole) procedures are used to restore blood flow through the graft, although occasionally a bypass operation may have to be carried out. •Endoleak: oPersistent blood flow in the aneurysm sack after endovascular repair is defined as an endoleak and is considered a complication of the procedure as the primary objective of endovascular aneurysm repair is to exclude the aneurysm sack from the circulation. Depending on the nature of the endoleak, the persistent blood flow in the aneurysm sack means that the sack may still be pressurised and therefore likely to rupture. Endoleaks caused by holes in the graft material, insufficient apposition of the stent graft against the aortic wall in the landing zone or disconnection of overlapping stent graft components require intervention in order to depressurize the aneurysm sack and mitigate the risk of rupture. These endoleaks may be related to poor placement of the stent graft, graft material failure, graft migration or progression of aneurysmal disease. Lifelong surveillance is necessary to mitigate the risk associated with these endoleaks which develop in as many as 20-40% of patients during long term follow up. Alternatively, retrograde flow of blood through aortic side branches such as the intercostal arteries, into the aneurysm sac are innocuous and do not require any treatment. All these potential complications are understandably concerning. Rest assured our surgeons make every effort to ensure your risk is reduced to the lowest level possible through our expertise and experience. The overall risk of you suffering from a major complication that either threatens your life or leg is about 2%. When complications do occur we deal with them rapidly and appropriately.
What happens after the operation?
The majority of people remain in hospital for one day for monitoring and recuperation. Patients are encouraged to mobilise as soon as possible after the procedure. On the day after the operation a chest X-ray will be performed to assess the position of the stent graft. Patients should be fully mobile directly after the operation. Throughout the early period of recuperation there will be discomfort at the site of the operation which we treat with pain medication.
What happens when I go home?
Although at the time of discharge we ensure you are safe to go home, we ask that there is a responsible adult with you for the first few days following discharge. You will be able to have a shower at 48 hours post-surgery but we ask you to refrain from bathing until the wounds are fully dry. For the first few weeks post-surgery there is often wound pain and discomfort. You may feel physically exhausted doing relatively minor activity, rest assured this is entirely normal and improves with time. The majority of people are able to return to work within 2 weeks of discharge, but this does depend on the nature of your employment, the type of TEVAR operation you have had and how well you recuperate from your surgery. If in any doubt please wait until you have been reviewed in clinic by your surgeon.
When will I be able to drive?
You are able to drive when you are able to perform an emergency stop and are able to concentrate fully on driving. Overall, we advise you to not drive a car for the first 4 weeks post-surgery or until you have pain free movement of your foot and knee, and are able to stamp your foot on the ground. Different rules apply for different ‘Group’ license holders and we recommend contacting the DVLA and your car insurance company for further advice.
Will I need to see the surgeon again?
We review all TEVAR patients in clinic approximately 6 weeks following discharge. Everyone who has undergone TEVAR surgery is entered into a surveillance programme to help prevent stent graft related complications through early identification of graft migration or kinking or endoleak.
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What should I do next?
If you think you have one of these conditions or any of the described symptoms we recommend you seek medical advice.
For further information or to arrange an appointment at Circulation Clinic
Enquiries: 0345 3690106
Figure 1: View of a TEVAR from the side with ribcage removed. The TEVAR arches around the heart (white arrow)
Figure 2: 3D reconstruction with ribcage cutaway showing successful TEVAR (white arrow)
Figure 3: Position of TEVAR demonstrated within chest cavity with ribcage and heart removed from image