Patients with kidney failure require an artificial means of cleaning the blood to stay alive. One way to do this is to run their blood through a machine in a procedure called hemodialysis. To receive hemodialysis, patients must have reliable access to their blood stream in such a way that permits high rates of blood flow to and from the hemodialysis machine. This is ideally performed through an arteriovenous fistula, where a vein is connected to an artery to create a high flow state in the vein. The preferred vein for creating an AV fistula is a superficial vein in the arm called the cephalic vein. It may be connected to the radial artery at the wrist or, if the vein is too small in the forearm but larger in the upper arm, it may be connected to the brachial artery at the elbow. The fistula is usually created in the non-dominant arm but can be created in the dominant arm. If no cephalic vein is available, a deeper vein called the basilic vein may be used to create an AV fistula to the brachial artery. However this vein is too deep to be accessed in its normal location, so it must be moved to a new location under the skin to be accessed, which involves a somewhat larger operation. Connecting the vein to the artery and moving it to a more superficial location is sometimes done in one stage or two stages, depending on the quality of the vein since marginal veins seem to do better if they are moved after they mature.
After the vein matures over a period of 6-8 weeks, it may be accessed with needles each time the patient comes to the dialysis clinic. However repeated trauma to the vein from accessing it with needles can result over time in narrowings called stenoses, or dilations called aneurysms. As a result repeat interventions on fistulas are common, but fortunately these are frequently accomplished with catheter based interventions performed in an outpatient setting. We perform these interventions regularly in our office based catheterization lab at Advanced Vascular Therapy, LLC.
Some patients have no suitable vein available. In those cases, a plastic tube may be placed under the skin which is connected to an artery at one end and a deep vein at the other. This device is called an arteriovenous graft. AV grafts are much more prone to complications such as infection or bleeding compared to AV fistulas, so are only placed when absolutely necessary. AV grafts have also been made out of biological materials such as artery or vein harvested from human cadavers, or vein harvested from cows. These grafts are also available for use in certain circumstances. Finally, a large catheter is sometimes placed in a deep vein in the neck to provide temporary access while more appropriate long term access is being established. However dialysis catheters have the highest rate of complications and all efforts possible should be made to avoid them.
TOS is a condition where structures get compressed between the first rib and clavicle (collar bone) as they pass out of the chest and into the arm, through an anatomical space known as the thoracic outlet. Three structures pass through this space: the subclavian artery, the subclavian vein, and several nerve roots. All 3 structures are at risk for compression and symptoms vary depending on which is affected. If the artery is affected, people usually present with crampy pain in the arm. If the vein is affected, people usually present with DVT and a swollen, painful arm. These conditions are easy to identify with ultrasound or angiograms. If the nerves are affected, patients can experience pain in the arm, chest wall, or back. Involvement of the artery or vein can be identified with ultrasound and confirmed with
angiography. Nerve involvement is much more difficult to confirm, since there are multiple nerves that cross the thoracic outlet and they communicate with each other in a very complicated arrangement, so standard nerve tests like electromyography (EMG) and nerve conduction studies cannot localize the site of nerve pathology to the thoracic outlet. In addition, there are many other conditions which can cause pain in these regions, including cervical disc disease and carpal tunnel syndrome. Sometimes a procedure called a scalene block is used to diagnose neurogenic TOS. In the procedure, an anesthesiologist or pain specialist injects some local anesthetic and some steroid medicine into the scalene muscles that insert on the first rib. A positive result from a scalene block gives immediate pain relief (from the anesthetic) and sometimes long term pain relief (from the steroid). A positive block also predicts a good result with definitive treatment.
Definitive treatment of TOS involves removal of the first rib, in order relieve crowding in the thoracic outlet. This can be accomplished through one of three different surgical approaches. The preferred approach is through the axilla (armpit), where a small (4-5 cm) incision is made at the lower edge of the hair line. This approach gives an excellent exposure of the entire rib and is cosmetically the most acceptable. Altervative approaches include exposing the rib through an incision on the chest wall, either above or below the clavicle (the collar bone). These approaches are sometimes used if a reconstructive procedure is required on the artery or vein at the time of rib resection, but this is rarely necessary. The most commonly performed adjunctive procedure is angioplasty of persistent narrowings inside the subclavian vein that result from buildup of chronic scar tissue inside the vein. This is usually done in a separate procedure after the vein has been decompressed by rib resection. If patients present with venous TOS complicated by DVT, sometimes the DVT will be dissolved prior to rib resection in a catheter based procedure called thrombolysis, where clot busting enzymes are delivered directly into the blood clot via a special catheter placed inside the vein. Stents should never be placed inside the subclavian vein prior to rib resection but are sometimes placed to keep resistant stenoses propped open after rib resection.
Resection of the first rib is very safe but it does require a general anesthetic and patients usually spend one night in hospital. The main risk of the procedure is pneumothorax (air enters the chest cavity, causing the lung to pull away from the chest wall and collapse) resulting from tearing the very flimsy lining of the chest wall as it is dissected off the under surface of the rib. When this results, a small drain is placed in the chest cavity that is connected to a suction device to evacuate the air and re-expand the lung. The drain is removed the following morning so its placement does not result in a delay in discharge, but can lead to increased postoperative discomfort while it is in place.
Vascular malformations are abnormal proliferations of blood vessels that can lead to enlarging masses that can affect adjacent structures by compressing them or stealing blood flow away from them.
Vascular malformations can be catetgorized into high-flow lesions (often called artiovenous malformations, or AVMs) or low-flow lesions (often called venous malformations, or VMs) and can be found in the skin, soft tissues, internal organs, and even bones. Venous malformations can usually be observed or treated with simple excision. Arteriovenous malformations are generally more aggressive than VMs and are more likely to require treatment. They are not cancerous but can behave like them in that they can be difficult to eradicate, and are prone to recurrence after simple excision. Complex AVMs often require a coordinated approach by a multidisciplinary team of physicians using a combination of treatments such as catheter based embolization, direct ablation with percutaneous alcohol injection, and surgical excision.
Lymphedema is the term used to describe swelling that results from dysfunction of the lymphatic channels, a part of the circulatory system that carries clear fluid called lymph. As our blood circulates in our bodies, there is a constant exchange of fluid between the blood vessels and the surrounding tissues. More fluid leaves the blood vessels than returns to them, and this excess fluid is returned to the blood stream via a complex system of lymphatic vessels that ultimately drain the lymph into a long duct that runs along the spine and then joins a deep vein behind the left collar bone. Over one gallon of lymph fluid circulates through the lymphatic system each day. If the lymphatics become damaged or fail, swelling results –usually in the legs, the most dependent part of thebody. Lymphatics can become damaged from infections, physical trauma or surgery. Risk factors for failure are obesity and inactivity. Except in rare cases where a major lymphatic channel has been injured and may be repaired, there is no cure for lymphedema. However it can be controlled with faithful use of compression stocking, weight loss and increasing activity levels.
At Advanced Vascular Therapy, LLC, you will find a team of friendly, knowledgeable individuals who are dedicated to treating your vascular condition with the ideal therapy that gives you the best possible outcome. The majority of these treatments are minimally invasive, outpatient procedures that result in no wounds and minimal discomfort. As a result of our extensive investment in infrastructure and people, we are uniquely positioned in all of Oregon to deliver these treatments to you in a pleasant, low-stress environment. We hope you will visit us and allow us the privilege of treating your vascular condition in the near future.