This column summarizes patient cases posted to SIR Connect (SIR’s popular online member community), the responses from other SIR members and how that feedback helped the original poster. To see how SIR’s online community can help you, visit SIR Connect at connect.sirweb.org.
Original post
Does anyone have suggestions regarding a protocol for inducing GI bleeding during a mesenteric angio? Have a 70 y/o patient with recurrent intermittent bleeding that’s been localized by both endoscopy and nuclear imaging to the distal small bowel. He has multiple co-morbidities and will never go to surgery. A recent mesenteric angio performed this weekend was completely normal. Lots of potential for disaster but he is running out of options. Have heard of using heparin as it can be reversed but unsure of dose. Is there a role for tpa or is that too risky? Thx in advance.
—Kent Walker, MD
Read the full discussion thread.
Background
I completed residencies in both internal medicine and radiology at the University of Texas Health Science Center in San Antonio. My fellowship in VIR was at Baylor University Hospital in Dallas. I practice DR but spend 60–70 percent of my time with procedures. My primary interest is with interventional oncology procedure such as drug-eluting beads transarterial chemoembolization (DEB-TACE) and Y-90 treatment.
The patient in my SIR Connect post was a 78-year-old male with severe chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF) and diabetes mellitus (DM) who was felt not to be a good surgical candidate. He had approximately four bleeding episodes with bright red blood per rectum (BRBPR) and hypotension. A tagged red blood cell (RBC) scan showed activity in right lower quadrant (RLQ). Endoscopy showed blood coming from TI.
What prompted you to reach out regarding provocative mesenteric angiography?
The patient had three negative mesenteric angiograms before I performed a provocative attempt.
What posts were most valuable to you?
All of the posts were helpful but particularly the “How I do it” ones with dosage information.
How would you have approached this case in the absence of SIR Connect?
I had already asked my colleagues in both radiology and gastroenterology but they did not have relevant experience.
How did the solicited input impact the outcome of the case? Have you treated another patient in a different manner after aggregating information from your peers?
Although I appreciated the input, I was not able to induce bleeding and the patient’s problem subsequently resolved without intervention.
During the provocative attempt, I used 3,000 units of heparin and monitored the activated clotting time (ACT). I also used 200 mcg of nitroglycerin and 8 mg tPA. Literature suggests this will work only 30 percent of the time.
I will definitely try again with the next negative mesenteric angiogram and not wait for the patient to rebleed. With the next case, assuming I can localize the bleeding to a single vascular distribution, I will be even more aggressive with the medications.
Additional commentary
The rationale behind the provocative technique is to evoke the source of clinical gastrointestinal bleeding, which is not readily apparent during angiography. This source may or may not have been previously identified on prior imaging, such as CT angiography or nuclear scintigraphy. Once the bleeding vessel is angiographically identified, the operator may choose embolization with gelfoam, coils or particle spheres. In certain circumstances, the vessel may be marked for surgical intervention with 2–10 mL methylene blue or a coil.
Respondents offered both evidence-based support and anecdotal experience. For instance, a series of 36 patients undergoing provocative mesenteric angiography published in the Journal of Vascular and Interventional Radiology (JVIR; Kim et al. 2010) reported angiographically visible extravasation in 31 percent of provoked cases with successful control of bleeding in 10 out of those 11 cases. Generally, a combination of an intra-arterial anticoagulant (heparin, 25–100 mg), vasodilator (nitroglycerine 100–300 mg, papaverine or verapamil 100–200 mg) and thrombolytic (tPA; 10–50 mg) was suggested to maximize chances of provocation (Zurkiya and Walker 2015). Another option includes systemic intravenous heparin therapy with weight-based dosing.
Overall, the combination of medications and dosing varies within the literature and clinical practice, highlighted by the protocols that respondents suggested. A generally accepted step-wise protocol (Kim et al. 2010) involves intra-arterial application of a heparin bolus along with an intra-arterial vasodilator, followed by an initial low dose of tPA. This step is followed by selective mesenteric angiography which, if negative, prompts the operator to utilize a vasodilator with sequentially higher doses of tPA followed by angiography.
Anecdotally, a provoked GI bleed is generally less severe or equal to the patient’s presenting bleed but respondents offered pre-procedural pearls such as keeping units of blood on hand, involving the anesthesia team, and informing the surgical service that a provocative angiogram will be performed so that support may be on hand in the potential event of a complication.
In conclusion, appropriately executed provocative measures may increase the diagnostic and therapeutic yield of mesenteric angiography for gastrointestinal bleeding. In this instance, SIR Connect was able to assist Dr. Walker in identifying a provocative angiographic protocol that he felt comfortable using with his high-risk surgical patient.
References (please refer to the SIR Connect thread for a full list of articles provided by respondents):
- Kim, Charles Y., Paul V. Suhocki, Michael J. Miller, Mazhar Khan, Gemini Janus, and Tony P. Smith. “Provocative Mesenteric Angiography for Lower Gastrointestinal Hemorrhage: Results from a Single-Institution Study.” Journal of Vascular and Interventional Radiology: JVIR 21, no. 4 (April 2010): 477–83. doi.org/10.1016/j.jvir.2009.11.021.
- Suhocki, Paul V. “Provocative Angiography for Obscure Gastrointestinal Bleeding.” Techniques in Gastrointestinal Endoscopy 5, no. 3 (July 1, 2003): 121–26. doi.org/10.1053/S1096-2883(03)00037-8.
- Zurkiya, Omar, and T. Gregory Walker. “Angiographic Evaluation and Management of Nonvariceal Gastrointestinal Hemorrhage.” American Journal of Roentgenology 205, no. 4 (September 23, 2015): 753–63. doi.org/10.2214/AJR.15.14803.
