What is hereditary hemorrhagic telangiectasia (HHT)?
HHT is a hereditary condition of abnormal blood vessels which affects approximately one in 5,000 people. People with HHT lack certain small capillaries that normally connect arteries to veins. Without these capillaries in key locations, blood flows directly from the artery to the vein, causing very fragile vessels that may bleed or result in other problems.
When the abnormal vessels are small vessels—such as those that occur in the nose, mouth, face and fingers—they are called telangiectasias. Large vessel abnormalities are called arteriovenous malformations (AVMs), and can be found in the brain, liver, or lung. Less often, they are seen in other parts of the body, such as the spine or the intestines.
HHT is an autosomal dominant condition, which means that there is a 50% chance that the genetic mutation would be passed to each offspring. HHT has no association with gender or race.
How is HHT diagnosed?
HHT can be diagnosed genetically or clinically. If you have a family history of HHT, you can visit a genetic counselor, who will send your blood to a special lab which looks for the mutation known to cause HHT. The test is successful in identifying the gene in about 85% of cases.
Clinically, HHT can be diagnosed using four criteria, called the Curacao Criteria:
- telangiectasias (abnormal small blood vessels most often seen on the mouth, fingers, and face)
- AVMs of the large organs, such as brain, liver, and lung
- history of HHT in a first-degree relative
Patients who meet three or more criteria likely have HHT. Those with two possibly have HHT, and those with one probably do not. The Curacao Criteria is excellent in ruling out HHT in adults, since 90 percent of patients will show the characteristics of the disorder by age 40. It is not as useful in diagnosing children, since nosebleeds, telangiectasias, and AVMs may not be apparent until later in life.
Some of the symptoms of HHT do not have an effect on quality of life. In more extreme cases, the nosebleeds and telangiectasias can cause severe anemia requiring transfusions or other procedures. AVMs can also cause significant morbidity, such as bleeding, stroke, brain infection, shortness of breath, or heart failure.
How is HHT treated?
Treatment for HHT at Columbia's HHT Center varies depending on the severity of the symptoms and which organ systems are involved. Our specialists are highly-respected experts in their respective fields, which include neurosurgery, interventional neuroradiology, ENT, pulmonology, pediatrics, and interventional radiology.
Pulmonary AVM Embolization
AVMs in the lungs are treated by an interventional radiologist. The procedure is called pulmonary AVM embolization, and is most often performed as a same-day outpatient procedure. Embolization is particularly desired for lung AVMs because it is low-risk and highly effective. The goal of embolization is to stop the abnormal communication between the artery and the vein, thereby preventing complications such as stroke, brain abscess, shortness of breath, heart failure, and even bleeding.
How do I get ready for the procedure?
You will be given a sedative before the procedure, and should not eat or drink anything for four to eight hours before your exam. Although most patients leave the hospital the same day as their procedure, some patients are admitted overnight for additional monitoring. Bring what you need for an overnight stay.
What will happen during the procedure?
The interventional radiologist will insert a catheter in the groin to access the femoral vein. While monitoring the location of the catheter using fluoroscopy (a type of x-ray) the physician steers the catheter through the blood vessels and into the lung. Eventually, a very small catheter is steered directly to the AVM. At this point, the interventional radiologist will decide which type of device to use to stop the blood flow into the AVM. This device is most often a metallic coil. Once it is confirmed that there is no flow going to the AVM, all catheters are removed, and a band-aid is placed at the groin.
Are there any risks?
In general, interventional therapy is safe and commonly associated with only minor side effects, including low-grade fever, nausea, and pain. The most serious risk is that an interventional procedure may cause hemorrhage, or bleeding, and, very rarely, death.
After the procedure
After your lung AVM is treated, you will be monitored in our recovery room for several hours. In most cases, patients are discharged in the late afternoon following their procedure. Most patients report mild chest pain for several days after the procedure. This is normal and goes away with over the counter pain medications. Patients typically resume normal activities soon after leaving the hospital. Some patients even report higher energy levels after the AVM is treated.
Visit Cure HHT for more information about HHT and its treatment.
Make an Appointment With the Columbia HHT Center
Appointments can be made by calling the center at 212-305-7094. Initial visits are with Sergei A. Sobolevsky, MD, the medical director of the center. Afterwards, referrals to subspecialists will be made as needed.