Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_595_Библиотеки_им_академика_М_И_Перельмана.pdf
This page intentionally left blankThis page intentionally left blank
Chapter 5
Interventional Radiology in the Management
of Gastrointestinal Haemorrhage
Lenny Tan*
Introduction
Gastrointestinal bleeding is divided into:
Upper GI bleed — occurring proximal to the ligament
of Treitz, i.e. the oesophagus, stomach and duodenum.
Lower GI bleed — from the rest of the small bowel
and colon.
Bleeding may be:
Direct into the lumen from a primary pathology in that
segment of bowel.
Indirect as in transpapillary bleeding through biliary
or pancreatic ducts. It may be inflammatory, malignant or postoperative in origin.
There are no reliable Singapore figures for frequency and causes of GI bleeding. In the US and UK,
it is estimated that the incidence of upper GI bleeding
is 100/100 000 adults/year with a mortality of 5%–14%.
For those under age 60 with no co-morbidities, it is
much lower at 0.6%.
Lower GI bleed occurs in 24.4/100 000 adults/year
in similar publications.
It is significant that the majority of gastrointestinal
bleeding will stop on its own without direct treatment
but may recur. Often, fluid and/or blood replacement
is all that is required.
It is particularly important to first determine if
the patient is still bleeding at the time of presentation before any investigation or intervention is
considered.
Various parameters have been used.
Published data indicate that:
1) when BP is < 90 mmHg, positive angiography rate
is 87% vs 12% if BP higher
2) if patient requires transfusion of 5 units of blood,
positive rate is 84% vs 16% if less
3) if hemoglobin falls more than 5 gm/ml, positive
rate is 85% vs 26%
4) heart rate, BP are useful clinical indicators
Patient will likely be in shock when > 40% of blood
volume is lost.
1
Management Options
The current practice is first to perform upper GI
endoscopy to exclude upper GI bleed and to institute
appropriate treatment if found.
If endoscopy is negative, CT angiography and
possibly catheter angiography with a view to embolisation or surgery are options.
* Lenny Tan, MD, FSIR, Emeritus Consultant, Department of Diagnostic Imaging, National University Hospital and Professor, National
University of Singapore, Singapore.
43
44 Atlas of Complicated Abdominal Emergencies
Figure 1.
Inadvertent endoscopic injection of glue into hepatic artery.
In a series of 163 patients with upper GI bleed over
11 years, Shenker et al.
was successful and no further bleeding occurs,
mortality is 11%. This compares with 68% if unsuccessful. These figures closely parallel other published
series from different institutions.
Bleeding on endoscopy or angiography may be
diffuse over a wide area as in haemorrhagic gastritis,
duodenitis and is a clinical dilemma. It would be
difficult to embolise completely, and equally difficult
to treat by endoscopy or surgery.
Endoscopy provides both diagnostic and therapeutic potential in the upper GI tract. However, care
should be exercised particularly in the use of liquid
embolic material which could be inadvertently injected
(Fig. 1).
2
found that if embolisation
Figure 2.
Subselective injection into caecal artery showing site of
bleeding.
Catheter Angiography
Angiography must be selective and preferably subselective. All potential supply vessels must be studied
and include the Coeliac Axis, Superior and Inferior
Mesenteric Arteries and their branches with the use of
microcatheters in more peripheral vessels (Figs. 2 and 3).
Figure 3.
Bleeding site shown in injection close to bleeding artery.
It is significant to mention that there are extensive
collaterals around the stomach and duodenum and flow
patterns should be fully understood before intervention
Chapter 5 Interventional Radiology in the Management of Gastrointestinal Haemorrhage 45
in this area. It may be necessary to occlude several
arteries to reduce perfusion and encourage thrombosis
to develop before bleeding ceases.
Angiography has been variously estimated as
likely to be positive when the bleeding rate is at least
0.5 mL/min. The advent of good digital subtraction
angiography greatly enhances its sensitivity, which
may be increased, tremendously (by a factor of 5 to
9) depending on various factors, including patients
ability to cooperate and the equipment available.
The use of microcatheters and very selective
catheterisation of suspected bleeding vessels further
improve successful detection and management.
CT Angiography
MDCT has high contrast sensitivity and plays a
very important role especially in post-trauma patients.
Publications on its role in GI bleeding confirm its
value. It demonstrates active bleeding, the exact site
and possible pathology by way of extravasation of
contrast injected.
In published series, the cohorts are usually small
but results consistent. The patient, however, must be
bleeding at the time of scan. So do not delay the study
to stabilise the patient as bleeding may have stopped
by then.
All studies indicate that the inclusion of arterial and
delayed phases with MDCT reformation in at least
coronal/sagittal planes are helpful (Figs. 4 and 5).
Delayed scans are particularly useful to detect very
small bleeds.
Direct signs of bleeding are seen as extravasation
of contrast into the lumen of bowel or attached organs
(Figs. 6 and 7). Indirect signs such as false or true
aneurysms, irregularity of vessels, vessel cut-off and
shunting may be seen in patients without extravasation (Fig. 8).
2
angiography is utilised to take advantage of
CO
its low viscosity compared with contrast media. There
are many reports published comparing its value with
contrast angiography. In properly equipped centres,
the detection rate is favourable with reported comparisions of 44 % vs 14%.
3
Its value lies in its lack of toxicity and being less
viscous than contrast media, hence its ability to exit a
small bleeding point is greatly enhanced. However,
there are some difficulties in this technique and it carries a larger dose of radiation.
Figure 4.
CT angiogram showing delayed — accumulation of contrast in caecum.
46 Atlas of Complicated Abdominal Emergencies
Figure 5.
Angio shows bleeding artery and post embolism.
Figure 6.
Demonstrates bleeding into lumen of stomach.
There may be no nephrotoxicity associated with
medical CO
2
but technical problems may arise if
segmentation or break-up of the column of gas occurs.
Other variations include CT angiography with
carbon dioxide given through a selectively placed
catheter amongst others.
Many variations and combinations of the above
techniques have been tried but none have gained
general acceptance.
Radioisotope imaging, either by way of RBC scintigraphy, sulphur colloid, is seldom used in acute
bleeding because of the longer time taken for the
Chapter 5 Interventional Radiology in the Management of Gastrointestinal Haemorrhage 47
Figure 7.
Bleeding into ileum in typhoid enteritis.
control bleeding if at all. The additional disadvantage
is the long duration the catheter is maintained in the
vessel with the potential hazards of dislodgement,
thrombus formation and ischemia. The patient will
need careful monitoring and outcomes are uncertain.
Success with vasopressin occurs in 52% as com-
pared with 88% in embolisation.
4
Embolic Agents
Which embolic agent should be used?
Embolisation must be carried out with absolute
accuracy. There is no option for flow directed delivery
as the potential for unintended embolisation and its
consequences are no longer acceptable.
All particulate material must be accurately deployed
as they may be impossible to retrieve.
Unfortunately, there has never been any randomised
trial on embolic material available.
Various types, including gel foam particles, PVA
particles, microcoils, have been used. It is not advisable to use liquid embolic material as it is difficult to
control its delivery.
If microcoils are used, it must be accurately
deployed and if one cannot advance beyond the
marginal artery, it should be avoided (Figs. 9–12).
Figure 8.
Aorto-esophageal fistula on CT.
procedure. Its value lies in very slow and intermittent
bleeds as in Meckels diverticulum.
Vasopressin perfusion has been used previously
as a vasoconstrictor to encourage thrombosis at the
bleeding point.
It is hardly used today because of its cardiovascular
effects as well as the longer time taken to effectively
Diffi culties
Technical difficulties are often an issue. Sometimes,
it is not possible to get close enough to the bleeding
vessel or in the process of advancing the guidewire/
catheter system, and the vessel is traumatised
(Fig. 13). This should always be borne in mind when
conducting such procedures.
Contraindications to Angiography/CT/
Embolisation
1) Sensitivity to contrast media is an absolute con-
2
traindication and CO
the preferred alternative.
angiography would then be
48 Atlas of Complicated Abdominal Emergencies
Figure 9.
Catheter is very peripheral to deliver embolic material.
Figure 10.
Duodenum bleed with coils at both ends of artery.
Chapter 5 Interventional Radiology in the Management of Gastrointestinal Haemorrhage 49
Figure 11.
Coil delivered peripherally.
2) Renal failure is another relative contraindication
depending on the severity of bleeding and need
for intervention. Appropriate rehydration is
important.
3) Previous extensive surgery or radiotherapy may
have altered the circulation and the risk of
infarction is greatly increased. This should be
borne in mind.
Complications of Angiography
Complications are usually related to the puncture
site, i.e. haematoma. Other possibilities include true/
false aneurysms and a/v fistula.
Trauma to the arterial/venous structures in the process of manipulating the catheter/guidewire system is
particularly likely as small vessels are involved.
Contrast media sensitivity and contrast nephropathy have been mentioned previously.
Unintended embolisation can occur if particles are
too small, if injection had been too forceful or the
catheter badly placed.
Liquid sclerosants are difficult to control and may
lead to necrosis. It is preferable not to use them.
Figure 12.
Tumour presented with bleeding embolised.
50 Atlas of Complicated Abdominal Emergencies
Figure 13.
Trauma to vessel during catheter angiography.
Outcomes
Technical success rates are very high — varying
from 80%–100% in various series.
Initial control of bleeding occurs in 71%–86% in
various series.
It is significant that if embolisaton is performed
distal to the marginal artery in the colon, recurrence is
almost 0% vs 52% if delivered more proximally.
5,6
Technical failure is often due to vessel spasm or
tortuosity preventing adequate access close to the
bleeding point.
Clinical success is more difficult to measure as it
cannot predict collateral vessels that may open up and
coagulopathies after severe blood loss.
Indirect Bleeding
These include haemobilia often from previous
surgery and treatment in the first instance is usually
conservative. If that fails, embolisation of the abnormal
vessels demonstrated at angiography is the treatment
option available.
Pancreatic aneurysms/pseudoaneurysms, particularly associated with pancreatitis, warrants separate
consideration. Mortality exceeds 90% with conservative management.
Aneurysms commonly involve the splenic artery
and the pancreatico-duodenal arcades, and should be
managed surgically. Radiology may facilitate by
reducing the likelihood of bleeding with appropriate
embolisation (Fig. 14).
Figure 14.
Pancreatitis with aneurysm-embolised before surgery.
Figure 15.
Chapter 5 Interventional Radiology in the Management of Gastrointestinal Haemorrhage 51
Aneurysm embolised — arteries coiled at both sides.
Figure 16.
Larger aneurysm — coils in aneurysm only.