therapeutic embolisation of arteriovenous malformations

1
ABSTRACTS 555 Dilatation was performed under fluoroscopic control with a 15-22 mm Cook oesophageal balloon catheter. No complications were registered when benign strictures were dilated. Two complications occurred when malignant strictures were dil- ated. In one patient the rupture of the tumour produced mediastinitis. In the other patient a small tear was noted within the tumour but without clinical symptoms. THERAPEUTIC EMBOLISATION OF ARTERIOVENOUS MALFORMATIONS D. J. ALLISON Hammersmith Hospital, London Therapeutic percutaneous embolisation is now the treatment of first choice for many types of arteriovenous malformation (AVM), haemangiomas and arteriovenous fistulae. These lesions are often difficult or even impossible to treat surgically, particularly AVMs, because of their extreme vascularity and the frequent existence of multiple feeding vessels which cannot all be identified at operation. The enlargement of apparently insignificant feeding arteries com- monly causes recurrence of these abnormalities following their attempted removal. Embolisation is an effective method of treatment for arteriovenous malformations and, providing due care is taken to avoid venous or inadvertent peripheral embolisation, is a relatively safe technique. Generally speaking the results of embolisation of purely venous (cavernous) malformations (i.e. venous lesions with normal or near-normal feeding arteries) is disappointing. This presentation reviews the current applications and techniques of embolisation in the treatment of arteriovenous malformations. INFERIOR VENA CAVAL FILTERS ROLF W. GUNTHER Technical University of Aachen, Klinikum, 5100Aachen, W. Germany Pulmonary embolism is still a significant cause of morbidity and mor- tality in hospitalised patients. Despite standard anticoagulation therapy pulmonary embolism remains a problem in a small number of patients, who do not respond adequately to anticoagulation or cannot be anticoagulated. Recurrent embolism in these patients necessitates a mechanical barrier in the inferior vena cava to prevent migration of life-threatening subsequent emboli. For this reason, a number of operative techniques and intraluminal devices have been developed. The most important of these techniques have used the Kimray-Green- field and the Mobin-Uddin filters. In recent years, the Kimray-Green- field filter has been increasingly favoured because of its high patency rate (98%) when compared with the Mobin-Uddin filter (40%). Since the large calibre of these filters usually requires venotomy for inser- tion, new types of filters have been developed for percutaneous intro- duction. One of these filters was designed by us and consists of helical basket and anchoring legs. The filter was tested in vitro and in vivo and was applied clinically in 23 patients. It is highly effective in capturing small and large emboli. Local thrombogenicity of the filter as observed in two patients can be eliminated by systemic heparinisation for a short period. Long-term anticoagulation seems unnecessary. PERCUTANEOUS GASTROSTOMY A. LUNDERQUIST, H. STRIDBECK, K. IVANCEV and C. LUNDSTEDT University Hospital, Lund, Sweden Percutaneous gastrostomy was performed because of different nutri- tional problems in 15 patients aged 62 to 87 years. A naso-gastric tube was introduced with its tip into the stomach and the patient placed on an angiographic table with biplane fluoroscopic facilities. After intra- venous Buscopan (hyoscine-N-butylbromide, Boehringer, Ingelheim) administration; the stomach was inflated with air and from informa- tion given by vertical and horizontal fluoroscopy, the puncture site in the epigastrium was chosen. This should be where the stomach could be seen against the ventral abdominal wall without interpositioned organs. After sterilising the skin and in local anaesthesia, the puncture was performed in four patients with a Cook percutaneous gastrostomy needle. This made a one-step puncture of the stomach possible with introduction of an F7 balloon catheter. After a week this catheter was exchanged for an F12 catheter. In the other 11 patients different techniques were tried from introduction of an occlusion balloon cathe- ter into the stomach to a direct introduction of an F12 Foley catheter. Problems involved with the techniques are discussed. COILS WITHOUT TEARS D. J. ALLISON Hammersmith Hospital, London Steel coils are extremely useful embolisation agents since they can induce permanent occlusion of vessels when correctly used and, because their ultimate diameter is predetermined, can be used in relatively large vessels or shunts where particulate or liquid emboli might not lodge in the desired position. The use of coils for embolisation is not, however, without problems and all radiologists using coils should be aware of these. There are six principal aspects that require consideration: 1. The safe delivery and extrusion of the coil 2. The positioning of the coil in the desired site 3. The prevention of migration of the coil 4. The effective occlusion of the blood vessel concerned 5. The retrieval of lost or misplaced coils 6. The implications for the patient of the permanent presence of coils These six points will be dealt with in detail during the presentation. PERCUTANEOUS NEPHROSTOMY ROLF W. G1]NTHER Technical University of Aachen, Klinikum, 5100Aachen, W. Germany Percutaneous nephrostomy (PNS) offers a variety of diagnostic and therapeutic applications. Diagnostic applications include antegrade pyelography, perfusion pressure studies, percutaneous nephroscopy and percutaneous brush biopsy. A large number of therapeutic possibilities now exist, the most important of which are decompression in postrenal obstruction, antegrade ureteral stenting and percutaneous stone manipulation. The spectrum of therapeutic applications of PNS includes: 1. Decompression in postrenal obstruction 2. Diversion in urinary fistulas 3. Antegrade ureteral stenting 4. Percutaneous catheter extraction 5. Percutaneous stone manipulation 6. Percutaneous dilatation of stenoses 7. Percutaneous meatotomy 8. Transrenal ureteral occlusion PNS has a very low rate of complications and has replaced operative nephrostomy. Furthermore, it has proved particularly useful for the management of complications caused by ESWL therapy. SCIENTIFIC EXHIBITION MEASUREMENTS OF GASTRIC FUNCTION USING APPLIED POTENTIAL TOMOGRAPHY B. H. BROWN, D. C. BARBER, E. MANGNALL and N. W. READ Royal Hallamshire Hospital, Sheffield Applied potential tomography (APT) is a new, non-invasive technique that yields sequential images of the resistivity of gastric contents after subjects have ingested a liquid or semi-solid meal. This study validates the technique as a means of measuring gastric emptying. Experiments in vitro showed an excellent correlation between measurements of resistivity and either the square of the radius of a glass rod or the volume of water in a spherical balloon when both were placed in an oval tank containing saline. Images of abdominal resistivity were also directly correlated with the volume of air in a gastric balloon. Profiles of gastric emptying of liquid meals obtained using APT were very similar to those obtained using scintigraphy or dye dilution tech- niques provided that acid secretion was inhibited by cimetidine. Pro- files of emptying of a mashed potato meal using APT were also very similar to those obtained by scintigraphy. Measurements of the empty- ing of a liquid meal from the stomach were reproducible if acid secretion was inhibited by cimetidine. Thus, APT is an accurate and reproducible method of measuring gastric emptying of liquids and particulate food. It is inexpensive, well tolerated, easy to use and ideally suited for multiple studies in patients, even those who are pregnant.

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Page 1: Therapeutic embolisation of arteriovenous malformations

ABSTRACTS 555

Dilatation was performed under fluoroscopic control with a 15-22 mm Cook oesophageal balloon catheter. No complications were registered when benign strictures were dilated.

Two complications occurred when malignant strictures were dil- ated. In one patient the rupture of the tumour produced mediastinitis. In the other patient a small tear was noted within the tumour but without clinical symptoms.

THERAPEUTIC EMBOLISATION OF ARTERIOVENOUS MALFORMATIONS D. J. ALLISON Hammersmith Hospital, London

Therapeutic percutaneous embolisation is now the treatment of first choice for many types of arteriovenous malformation (AVM), haemangiomas and arteriovenous fistulae. These lesions are often difficult or even impossible to treat surgically, particularly AVMs, because of their extreme vascularity and the frequent existence of multiple feeding vessels which cannot all be identified at operation. The enlargement of apparently insignificant feeding arteries com- monly causes recurrence of these abnormalities following their attempted removal. Embolisation is an effective method of treatment for arteriovenous malformations and, providing due care is taken to avoid venous or inadvertent peripheral embolisation, is a relatively safe technique. Generally speaking the results of embolisation of purely venous (cavernous) malformations (i.e. venous lesions with normal or near-normal feeding arteries) is disappointing.

This presentation reviews the current applications and techniques of embolisation in the treatment of arteriovenous malformations.

INFERIOR VENA CAVAL FILTERS ROLF W. GUNTHER Technical University of Aachen, Klinikum, 5100Aachen, W. Germany

Pulmonary embolism is still a significant cause of morbidity and mor- tality in hospitalised patients. Despite standard anticoagulation therapy pulmonary embolism remains a problem in a small number of patients, who do not respond adequately to anticoagulation or cannot be anticoagulated. Recurrent embolism in these patients necessitates a mechanical barrier in the inferior vena cava to prevent migration of life-threatening subsequent emboli. For this reason, a number of operative techniques and intraluminal devices have been developed. The most important of these techniques have used the Kimray-Green- field and the Mobin-Uddin filters. In recent years, the Kimray-Green- field filter has been increasingly favoured because of its high patency rate (98%) when compared with the Mobin-Uddin filter (40%). Since the large calibre of these filters usually requires venotomy for inser- tion, new types of filters have been developed for percutaneous intro- duction. One of these filters was designed by us and consists of helical basket and anchoring legs. The filter was tested in vitro and in vivo and was applied clinically in 23 patients. It is highly effective in capturing small and large emboli. Local thrombogenicity of the filter as observed in two patients can be eliminated by systemic heparinisation for a short period. Long-term anticoagulation seems unnecessary.

PERCUTANEOUS GASTROSTOMY A. LUNDERQUIST, H. STRIDBECK, K. IVANCEV and C. LUNDSTEDT University Hospital, Lund, Sweden

Percutaneous gastrostomy was performed because of different nutri- tional problems in 15 patients aged 62 to 87 years. A naso-gastric tube was introduced with its tip into the stomach and the patient placed on an angiographic table with biplane fluoroscopic facilities. After intra- venous Buscopan (hyoscine-N-butylbromide, Boehringer, Ingelheim) administration; the stomach was inflated with air and from informa- tion given by vertical and horizontal fluoroscopy, the puncture site in the epigastrium was chosen. This should be where the stomach could be seen against the ventral abdominal wall without interpositioned organs.

After sterilising the skin and in local anaesthesia, the puncture was performed in four patients with a Cook percutaneous gastrostomy needle. This made a one-step puncture of the stomach possible with introduction of an F7 balloon catheter. After a week this catheter was exchanged for an F12 catheter. In the other 11 patients different techniques were tried from introduction of an occlusion balloon cathe- ter into the stomach to a direct introduction of an F12 Foley catheter. Problems involved with the techniques are discussed.

COILS WITHOUT TEARS D. J. ALLISON Hammersmith Hospital, London

Steel coils are extremely useful embolisation agents since they can induce permanent occlusion of vessels when correctly used and, because their ultimate diameter is predetermined, can be used in relatively large vessels or shunts where particulate or liquid emboli might not lodge in the desired position.

The use of coils for embolisation is not, however, without problems and all radiologists using coils should be aware of these. There are six principal aspects that require consideration:

1. The safe delivery and extrusion of the coil 2. The positioning of the coil in the desired site 3. The prevention of migration of the coil 4. The effective occlusion of the blood vessel concerned 5. The retrieval of lost or misplaced coils 6. The implications for the patient of the permanent presence of coils

These six points will be dealt with in detail during the presentation.

PERCUTANEOUS NEPHROSTOMY ROLF W. G1]NTHER Technical University of Aachen, Klinikum, 5100Aachen, W. Germany

Percutaneous nephrostomy (PNS) offers a variety of diagnostic and therapeutic applications. Diagnostic applications include antegrade pyelography, perfusion pressure studies, percutaneous nephroscopy and percutaneous brush biopsy. A large number of therapeutic possibilities now exist, the most important of which are decompression in postrenal obstruction, antegrade ureteral stenting and percutaneous stone manipulation. The spectrum of therapeutic applications of PNS includes:

1. Decompression in postrenal obstruction 2. Diversion in urinary fistulas 3. Antegrade ureteral stenting 4. Percutaneous catheter extraction 5. Percutaneous stone manipulation 6. Percutaneous dilatation of stenoses 7. Percutaneous meatotomy 8. Transrenal ureteral occlusion

PNS has a very low rate of complications and has replaced operative nephrostomy. Furthermore, it has proved particularly useful for the management of complications caused by ESWL therapy.

S C I E N T I F I C E X H I B I T I O N

MEASUREMENTS OF GASTRIC FUNCTION USING APPLIED POTENTIAL TOMOGRAPHY B. H. BROWN, D. C. BARBER, E. MANGNALL and N. W. READ Royal Hallamshire Hospital, Sheffield

Applied potential tomography (APT) is a new, non-invasive technique that yields sequential images of the resistivity of gastric contents after subjects have ingested a liquid or semi-solid meal. This study validates the technique as a means of measuring gastric emptying. Experiments in vitro showed an excellent correlation between measurements of resistivity and either the square of the radius of a glass rod or the volume of water in a spherical balloon when both were placed in an oval tank containing saline. Images of abdominal resistivity were also directly correlated with the volume of air in a gastric balloon.

Profiles of gastric emptying of liquid meals obtained using APT were very similar to those obtained using scintigraphy or dye dilution tech- niques provided that acid secretion was inhibited by cimetidine. Pro- files of emptying of a mashed potato meal using APT were also very similar to those obtained by scintigraphy. Measurements of the empty- ing of a liquid meal from the stomach were reproducible if acid secretion was inhibited by cimetidine. Thus, APT is an accurate and reproducible method of measuring gastric emptying of liquids and particulate food. It is inexpensive, well tolerated, easy to use and ideally suited for multiple studies in patients, even those who are pregnant.