Angiectasia describes the abnormal dilation of small blood vessels, including capillaries, venules, and arterioles. These malformed vessels have thin, fragile walls that lack normal supportive layers, making them prone to rupture and bleeding. While lesions can occur throughout the body, they are most often a source of bleeding within the gastrointestinal (GI) tract. The condition is generally acquired over time, frequently seen in older adults, but some cases are linked to inherited genetic disorders.
Defining Angiectasia and Its Manifestations
Angiectasia is a broad classification for vascular abnormalities, often overlapping with terms like telangiectasia and angiodysplasia. Telangiectasia refers to small, dilated vessels, typically less than one millimeter in diameter, that appear close to the skin or mucosal surface in a spiderweb-like pattern. Angiodysplasia is the term frequently used when these lesions appear in the GI tract, presenting as small tufts of vessels vulnerable to trauma and bleeding.
The location of these lesions determines their primary manifestation and clinical significance. Gastrointestinal angiectasia is important, representing a leading cause of unexplained GI bleeding in people over 60. These lesions are most frequently found in the right side of the colon and the small intestine. Endoscopically, they often appear as punctate or patchy areas of redness, sometimes displaying a distinct, branching, or “arborizing” pattern.
Beyond the digestive tract, angiectasia can appear on the skin as common, benign, age-related cherry angiomas. Spider angiomas, another form of acquired angiectasia, are often linked to elevated estrogen levels or chronic liver disease. The vessel walls in all these locations are structurally compromised, typically lacking a layer of smooth muscle, which explains their fragility and tendency to bleed easily.
Causes and Underlying Conditions
Angiectasia develops from acquired factors that increase local vascular pressure and genetic conditions that predispose individuals to vessel wall weakness. In acquired cases, age-related degeneration is a primary driver, often combined with chronic medical conditions that disrupt normal blood flow dynamics. The long-term, intermittent obstruction of submucosal veins, possibly from intestinal wall tension, can cause the capillaries to gradually distend and twist.
Several systemic diseases are strongly associated with acquired angiectasia, including chronic kidney disease and liver cirrhosis. In chronic kidney failure, a tendency toward bleeding and a buildup of toxins can exacerbate vessel fragility. Liver cirrhosis leads to portal hypertension, which increases pressure in the veins feeding the digestive tract, forcing vessels to dilate.
A strong link also exists between angiectasia and certain cardiac conditions, most notably aortic stenosis, a combination sometimes referred to as Heyde syndrome. The turbulence caused by a narrowed aortic valve may destroy large von Willebrand factor multimers, which are necessary for normal blood clotting, leading to increased bleeding. Furthermore, the use of left ventricular assist devices (LVADs) increases the risk of angiectasia, likely due to a similar mechanism of blood cell damage under high shear stress.
In contrast to acquired forms, hereditary angiectasia is caused by genetic defects that impair the structure and function of blood vessel walls. The most recognized form is Hereditary Hemorrhagic Telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, an autosomal dominant disorder. HHT is caused by mutations in genes like ENG or ACVRL1, which are involved in the transforming growth factor-beta (TGF-ß) signaling pathway. Disruption of this pathway results in the formation of thin-walled, fragile vessels throughout the body.
Identifying Internal Angiectasia
Locating internal angiectasia, especially when causing obscure gastrointestinal bleeding, relies on direct visualization techniques. Standard upper endoscopy and colonoscopy are the initial steps, allowing physicians to examine the lining of the stomach, duodenum, and large intestine. However, angiectasias are commonly found in the small bowel, a segment often inaccessible to these routine procedures.
For lesions located deeper in the small intestine, wireless capsule endoscopy (CE) is a preferred, non-invasive method. The patient swallows a pill-sized camera that captures images of the small bowel lining as it passes through, identifying the characteristic red spots of angiectasia. If a lesion is identified by CE and requires treatment, a more advanced technique called enteroscopy is used.
Enteroscopy, which can be balloon-assisted, allows a flexible scope to be advanced further into the small bowel than a standard endoscope. This provides a clear path for therapeutic intervention once the lesion is localized. In complex or actively bleeding cases, angiography may be employed, which involves injecting a contrast dye to highlight the abnormal vascular structures on specialized CT or MRI scans.
Management and Treatment Approaches
The primary goal of managing angiectasia is to control or prevent bleeding that leads to chronic blood loss and iron deficiency anemia. The most effective treatment for GI angiectasia is endoscopic therapy, which involves directly obliterating the fragile vessels. Argon Plasma Coagulation (APC) is a common technique that uses a jet of ionized gas to deliver heat energy to the lesion, causing it to coagulate and seal the blood vessel.
Other endoscopic modalities include bipolar or heater probe coagulation, or the application of specialized mechanical clips. Despite successful initial treatment, rebleeding is common, sometimes necessitating multiple endoscopic sessions over time. This high recurrence rate often requires additional strategies to stabilize the patient.
Medical management is often employed for widespread or recurrent bleeding that is difficult to control with endoscopy alone. Certain anti-angiogenic drugs, such as thalidomide and bevacizumab, target growth factors like VEGF that promote the formation of these abnormal vessels. Hormone therapy, such as octreotide, has also been explored to reduce bleeding episodes.
Beyond direct treatment, care involves addressing the underlying systemic conditions contributing to the problem. Managing chronic kidney disease, treating liver disease, or correcting aortic stenosis can help reduce the overall risk and severity of angiectasia-related bleeding. Iron supplementation and blood transfusions remain supportive measures to manage the resultant anemia.