Hemostasis of Acute Lower Gastrointestinal Bleeding


Clip

Width of open jaws (mm)

Rotatable

Reopening capability

MRIa conditional

Resolution Clip

(Boston Scientific, Inc.)

11

Nob

Yes

Yes

QuickClip 2

(Olympus Corp.)

 9

Yes

No

No

QuickClip 2 Long

(Olympus Corp.)

11

Yes

No

No

Instinct clip

(Cook Endoscopy, Inc.)

16

Yes

Yes

Yes


a MR magnetic resonance imaging

bSome rotation capability feasible with protective sheath off



Clip deployment is targeted at the bleeding lesion or visible vessel. Additional clips can then be placed on each side of the clipped lesion to ligate the feeding vessel. If the first clip is placed on one side of the vessel, the second clip is placed on the other side to ensure hemostasis. Thus, two to three clips are typically placed to target a bleeding source (Video 15.2).

Recently, over-the-scope clips (OTSC) have become available for treatment of focal bleeding lesions, typically in cases refractory to standard endoscopic therapies. Although the majority of the OTSC experience to date has been in the management of upper GI bleeding, there are several reports regarding the successful use of OTSC in lower GI bleeding [10].

Endoscopic band ligation (EBL) is typically used for esophageal variceal bleeding, although there are reports of successful banding for diverticular bleeding [11]. The bleeding diverticulum should be marked with a tattoo or clip to aid in subsequent identification, and over-suctioning excess tissue into the banding cap should be avoided to prevent entrapment of the entire colonic wall, which could lead to delayed perforation [12]. EBL requires withdrawal of the colonoscope after site marking for device loading and reinsertion of a gastroscope loaded with the banding apparatus to the bleeding site for band deployment. The logistics of instrument withdrawal and reinsertion may not be feasible in some settings.

Detachable loops or snares for ligation are particularly useful for constricting and tamponading the stalk of large pedunculated polyps before polypectomy. These nylon loops open to a diameter of 3 cm and once lassoed around the stalk, they are tightened to achieve hemostasis or cyanosis of the polyp, followed by loop release. Positioning the loop around the lesion may be difficult because of its floppy nature, and gradually opening the loop over the lesion may help with positioning. If needed, a loop-cutting device can section maldeployed loops. The loop can inadvertently cut through the stalk by constricting the loop too tightly. In contrast, premature loop deployment will result in inefficient tightening of the target lesion, and this can be avoided by slowly tightening and assessing the appearance of the lesion for ischemic change prior to release of the loop. Postpolypectomy loop placement to control active bleeding from a residual stump is feasible as long as enough stalk remains for capture by the loop.




Non-endoscopic Therapy for Lower GI Bleeding



Angiography


Similar to colonoscopy, angiography can be both diagnostic and therapeutic in lower GI bleeding. It is particularly useful in patients with ongoing bleeding whose colons are unprepped and in those with severe bleeding, which would likely limit visualization during colonoscopy. Angiographic vasopressin infusion is not commonly used due to its high bleeding recurrence rate and complications [13]. Super-selective microcatheter embolization is usually performed for hemostasis using small 2.5–3 Fr microcatheters that are advanced through larger catheters and through which various embolic agents can be deployed, including microcoils, microparticles, and glue. Initial clinical success with this technique is achieved in over 95 % of patients, with a rebleeding rate of about 22 %. The major concern with angiographic intervention lies in its potential for serious adverse events in about 17 % of cases, including bowel ischemia and infarction, hematoma, thrombosis, and vascular dissection [14].


Surgery


Surgical resection is the last resort for ongoing lower GI bleeding that is refractory to less invasive endoscopic and angiographic management, since it carries substantial morbidity and mortality, especially in emergent situations. Blind segmental resection is not recommended due to its high rate of recurrent bleeding, morbidity, and mortality. Segmental resection is preferred with lower rebleeding rates ranging from 0 to 14 %. Subtotal colectomy carries the lowest rebleeding rate (<5 %), but with higher morbidity than targeted segmental resection.


Specific Causes of Lower GI Bleeding


The differential diagnosis of acute lower GI bleeding is broad, although the vast majority of such bleeding is due to diverticulosis, ischemic colitis, angiodysplasias, neoplasia, and hemorrhoids (Table 15.2) [15]. The cause of lower GI bleeding remains uncertain in about 12 % of cases. The use of specific hemostatic tools for the most common lower GI bleeding lesions is highlighted here.


Table 15.2
Etiology of lower gastrointestinal bleeding































Source

Prevalence (%)

Diverticulosis

17–44

Colonic angiodysplasia

 2–30

Ischemia

 9–21

Malignancy

 4–14

Hemorrhoids/anorectal lesions

 4–11

Postpolypectomy

 6

Unknown

 8–12


Diverticular Bleeding


Multiple endoscopic options are available for treating a colonic diverticulum with active bleeding or stigmata of recent bleeding, including epinephrine injection, thermal coagulation, mechanical therapy, or a combination thereof [12]. Once a bleeding diverticulum is identified, the location should be marked with a submucosal injection of a tattooing agent to localize the bleeding area if subsequent endoscopic or surgical therapy becomes necessary. Alternatively, a clip can be placed next to the site to mark its location, although the clip is not meant to be served as a permanent endoscopic or fluoroscopic marker.

Epinephrine injection in four quadrants can control bleeding or close the mouth of the diverticulum by tamponade. A bleeding or non-bleeding visible vessel can be identified at the neck or at the dome of the diverticulum. Adherent clots can be removed using the cold snare guillotine technique (similar to the technique for upper GI bleeding), and any underlying lesion should be treated appropriately. TTS clips can be placed directly on the culprit vessel (Video 15.4) or used to close the entire diverticulum (Fig. 15.1) [16]. One study suggests that clip placement targeted at the vessel is more effective than closing the entire diverticulum in a “zipper” fashion [17]. If utilized, contact thermal therapy should be applied carefully, particularly in the dome of the diverticulum. The suggested treatment settings for bipolar coagulation are a power of 10–15 W and short 1–2 s pulse duration, with light to moderate probe-tissue contact pressure (Video 15.5). If clips or thermal therapy are not feasible due to difficult access, particularly in a narrowed, angulated sigmoid colon, EBL can be considered (Fig. 15.2). The band ligation cap is useful in this setting to facilitate access to the bleeding diverticulum. An area adjacent the bleeding diverticulum should be marked with a tattoo or clip to aid visual identification when an upper endoscope loaded with the banding device is subsequently introduced (Video 15.6).

A307467_1_En_15_Fig1_HTML.jpg


Fig. 15.1
(a) Diverticulum with stigmata of recent bleeding. (b) Clip placement for closure of diverticulum


A307467_1_En_15_Fig2_HTML.jpg


Fig. 15.2
(a) Diverticulum with visible vessel in the dome. (b) Endoscopic band ligation performed. (c) Appearance of post band ligation


Angiodysplasias


At colonoscopy, an angiodysplasia has a characteristic appearance of a 2–10 mm, red, fern-like, flat lesion with ectatic vessels radiating from a central vessel. Poor bowel preparation and use of meperidine and other opiates, which transiently decrease mucosal blood flow, could potentially hinder the identification of angiodysplasias. If there is a history of guaiac-positive stool or iron deficiency anemia, angiodysplasias should be treated even if not actively bleeding. Angiodysplasias without evidence of GI bleeding should not be treated.

Bleeding angiodysplasias can be treated with a variety of thermal therapies [12]. Clips may not be effective for angiodysplasias and are not typically used. Contact thermal coagulation begins with the outer feeder vessels and progresses toward the central vessel, although the focus should be on the central vessel. However, APC is more popular than contact thermal methods, with a reported 77–83 % success rate (Fig. 15.3) [18]. Over-insufflation of the colon should be avoided before and during therapy as it can increase the risk of perforation due to thinning of the colon wall. For a very large angiodysplasia, injecting epinephrine near the center vessel can shrink the size of the lesion and decrease the amount of coagulation needed.

A307467_1_En_15_Fig3_HTML.jpg


Fig. 15.3
(a) Colonic vascular ectasias. (b) Ablation with argon plasma coagulation

There is a potential role for medical treatment of angiodysplasias, particularly when numerous and diffuse, although most of the data are from studies of small bowel angiodysplasias. Octreotide administered subcutaneously in doses ranging from 100 μg to 500 μg two times a day may decrease the need for transfusions [19]. Thalidomide at a dose of 100 mg orally once a day may also decrease the rebleeding rate from angiodysplasias [20]. A randomized trial of estrogen-progesterone treatment for 1 year did not decrease the rebleeding rate from angiodysplasias, with higher morbidity and mortality [21, 22]. Hormone therapy may decrease bleeding from telangiectasias in patients with Osler-Weber-Rendu disease.

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May 30, 2017 | Posted by in GASTROENTEROLOGY | Comments Off on Hemostasis of Acute Lower Gastrointestinal Bleeding
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