LETTERS TO THE EDITORS The Editors invite readers to submit letters commenting on the contents of articles that appear in the Journal. Also welcome are brief communications in letter form reporting investigative or clinical observations without extensive documentation and with brief bibliography (five titles or less), not requiring peer review but open to critique by readers. Letters to the Editors should be no more than 500 words in length and they may have to be edited for publication.
Diagnostic evaluation of radioimmunoscintigraphy (RIS) with use of iodine 1234abeled antibodies against human granulocytes (1231~Anti-NCA95) for the detection of prosthetic vascular graft infection To the Editors: Despite improved diagnostic techniques such as contrast-enhanced CT scanning, ultrasonography, and magnetic resonance imaging, diagnosis of infected vascular grafts has been unsatisfactory until now. Nuclear medicine procedures have been developed to detect inflammatory lesions by use of different isotopes. The disadvantages of some of these methods for clinical use have not been overcome so far.id The purpose of our study was to determine the diagnostic value of radioimmunoscintigraphy by use of 1231Anti-NCA95 for the detection of infected vascular grafts.
MATERIAL
AND METHODS
Thirty examinations were performed in 17 patients after vascular reconstructive surgery and clinical suspicion of vascular graft infection. Whole-body gamma camera images were obtained between 4 and 24 hours after intravenous administration of 111 MBq 1231-Anti-NCA95 (Granuloscint, Mallinckrodt Diagnostca, Petten, The Netherlands). Scan results were interpreted without clinical information and were subsequently correlated with surgical findings, bacteriology, CT scanning, and clinical course.
RESULTS The diagnosis of vascular graft infection could be confirmed in 13 of 30 cases and could be excluded in 10 of 10 cases by scintigraphy (Fig. 1). In six cases scintigraphy yielded false-positive results, falsenegative results were found in one case, resulting in a sensitivity of 93% and a specificity of 62.5%. False-positive results were obtained in early prosthetic vascular infection exclusively until 4 weeks after surgery; whereas late infections were true positive in all cases.
DISCUSSION The incidence of vascular graft infection is reported to be low in the range of 2% to 6%. Since 24/41/30584
I
:’ -.:‘
,,
(..
I ,, :.I
, i,,
‘. ‘.
.‘, /.“/.
_,
,/ i,
Fig. 1. Radioimmunoscintigraphy using 1231-AntiNCA95 24 hours after injection demonstrates increased granulocyte accumulation along the vascular graft indicating infection.
lethality varies between 25% and 75%, early diagnosis is essential for adequate therapy.5 Scintigraphic examinations using indium 11 l-labeled immunoglobulins as well as other procedures have been described. Recently a murine antibody against human granulocytes (1231-Anti-NCA95) has been developed. Particular advantages of the scintigraphy with this antibody versus all other nuclear medicine procedures are the high image quality and the safe application of this agent, which makes an early diagnosis even 4 hours after injection possible. The in 703
704
Letters
Jouna! of VASCULAR SURGERY
to the Editms
vivo labeling of autologous granulocytcs has been validated as a scintigraphic test for inflammatory lesions. Time consuming vitality testing of the labeled granulocytes is not recommended. A shortcoming of this method is false-positive results in early infection caused by hematomas or physiologic wound healing, which may lead to increased granulocytc accumulations. In our series we did not observe any side effects after administration of this substance even in repcatcd examinations. Michad
&hs,
MI>
Bebbcrg Laboratory of Neuroscience University Hospital, UBC Site 2211 Wesbrook ,Mall Vancouver, British Columbia V6T Canada
1W5
Wo&a?tg Hepp, MD Gewg Banen, ML) R14th Lunpr, MD REFERENCES 1. Brunner IMC, ‘Mitchell KS, Baldwin JC. Prosthetic graft infection: limitations ofwhite blood cell scanning. J VASC SURC 1986;3:42-8. 2. Vorne M, Laitinen TJ, Lehtonen J, et al. 99mTc-leukocyte scintigraphy in prosthetic vascular graft infections. Nucl Med 1989;28:95-9. 3. Lawrence PE, Dries DJ, Alazraki N, Albo D. Indium 11 llabclcd leukocyte scanning for detection of prosthetic vascular graft infection. J VASC SUN 1985;2:165-73. 4. La IMuraglia GM, Fischman AJ, Strauss HW. Utility of the iridium Ill-labeled human immunoglobulin G scan for the detection of focal vascular graft infection. J VASC SURC 1989;10:20-8. 5. Bunt TJ. The management of infected grafts in reconstructive surgery. Thorac Cardiovasc Surg 1986;34:265-8.
Aortobifemoral
prosthesis:
a new design
To the Editurs:
The major problem in the surgery of atherosclerotic lesions of the distal aorta and the iliac arteries is the longevity of the restoration.’ This is mostly due to the progressive degradation of the distal circulation and the quality of the initial intervention. The initial intervention itself can crcatc the following functional anomalies: (1) a protusion of the prosthesis and conflicts with the digestive tract as well as with the superior mcscntcric artcry caused by an end-to-side anastomosis at the anterior face of the subrenal aorta; (2) an increase in aortic diameter caused by the lateral implantation of the prosthesis, thereby increasing the parietal tension of the aorta, which can create an
aneurysm;’ (3) turbulent flow at the end-to-side anastomosis site;” (4) competitive Aow between branches of the prosthesis and the stcnoscd iliac axcs4 Although an anatomic restoration done by end-to-end
Fig.
1. The new aortobifcmoral
prosthesis.
anastomosis on the aorta and the femoral arteries associated with the reimplantation of the inferior mcscnteric artery and hypogastric arteries can avoid the above inconveniences, this technique is longer and more difficult to implement and has not been adopted by most surgeons5 Another problem occurs in subrenal aortic aneurysm interventions when they are associated with external iliac artcry stenosis. In these cases the prosthesis is inevitably implanted by end on the subrcnal aorta and by side onto the femoral arteries. The evolution of the lesions along the external
iliac
arteries
threatens
retrograde
hypogastric
perfusion. In view of the technical difficulties and drawbacks listed above, we propose a new, easily implantable prosthesis, where all anastomosis are end to end, and whcrc the perfusion of the hypogastric arteries is preserved in a physiologic direction. This new aortobifemoral prosthesis is made of woven Dacron, and it is constituted by an aortic tube with two lateral anastomosed branches that radiate from the midpoint of the tube. The branches arc anastomosed at a 30-dcgrce angle, and their diameter is half of that of the principal tube (Fig. 1).
Diagnostic evaluation of radioimmunoscintigraphy (RIS) with use of iodine 1234abeled antibodies against human granulocytes (1231~Anti-NCA95) for the detection of prosthetic vascular graft infection To the Editors: Despite improved diagnostic techniques such as contrast-enhanced CT scanning, ultrasonography, and magnetic resonance imaging, diagnosis of infected vascular grafts has been unsatisfactory until now. Nuclear medicine procedures have been developed to detect inflammatory lesions by use of different isotopes. The disadvantages of some of these methods for clinical use have not been overcome so far.id The purpose of our study was to determine the diagnostic value of radioimmunoscintigraphy by use of 1231Anti-NCA95 for the detection of infected vascular grafts.
MATERIAL
AND METHODS
Thirty examinations were performed in 17 patients after vascular reconstructive surgery and clinical suspicion of vascular graft infection. Whole-body gamma camera images were obtained between 4 and 24 hours after intravenous administration of 111 MBq 1231-Anti-NCA95 (Granuloscint, Mallinckrodt Diagnostca, Petten, The Netherlands). Scan results were interpreted without clinical information and were subsequently correlated with surgical findings, bacteriology, CT scanning, and clinical course.
RESULTS The diagnosis of vascular graft infection could be confirmed in 13 of 30 cases and could be excluded in 10 of 10 cases by scintigraphy (Fig. 1). In six cases scintigraphy yielded false-positive results, falsenegative results were found in one case, resulting in a sensitivity of 93% and a specificity of 62.5%. False-positive results were obtained in early prosthetic vascular infection exclusively until 4 weeks after surgery; whereas late infections were true positive in all cases.
DISCUSSION The incidence of vascular graft infection is reported to be low in the range of 2% to 6%. Since 24/41/30584
I
:’ -.:‘
,,
(..
I ,, :.I
, i,,
‘. ‘.
.‘, /.“/.
_,
,/ i,
Fig. 1. Radioimmunoscintigraphy using 1231-AntiNCA95 24 hours after injection demonstrates increased granulocyte accumulation along the vascular graft indicating infection.
lethality varies between 25% and 75%, early diagnosis is essential for adequate therapy.5 Scintigraphic examinations using indium 11 l-labeled immunoglobulins as well as other procedures have been described. Recently a murine antibody against human granulocytes (1231-Anti-NCA95) has been developed. Particular advantages of the scintigraphy with this antibody versus all other nuclear medicine procedures are the high image quality and the safe application of this agent, which makes an early diagnosis even 4 hours after injection possible. The in 703
704
Letters
Jouna! of VASCULAR SURGERY
to the Editms
vivo labeling of autologous granulocytcs has been validated as a scintigraphic test for inflammatory lesions. Time consuming vitality testing of the labeled granulocytes is not recommended. A shortcoming of this method is false-positive results in early infection caused by hematomas or physiologic wound healing, which may lead to increased granulocytc accumulations. In our series we did not observe any side effects after administration of this substance even in repcatcd examinations. Michad
&hs,
MI>
Bebbcrg Laboratory of Neuroscience University Hospital, UBC Site 2211 Wesbrook ,Mall Vancouver, British Columbia V6T Canada
1W5
Wo&a?tg Hepp, MD Gewg Banen, ML) R14th Lunpr, MD REFERENCES 1. Brunner IMC, ‘Mitchell KS, Baldwin JC. Prosthetic graft infection: limitations ofwhite blood cell scanning. J VASC SURC 1986;3:42-8. 2. Vorne M, Laitinen TJ, Lehtonen J, et al. 99mTc-leukocyte scintigraphy in prosthetic vascular graft infections. Nucl Med 1989;28:95-9. 3. Lawrence PE, Dries DJ, Alazraki N, Albo D. Indium 11 llabclcd leukocyte scanning for detection of prosthetic vascular graft infection. J VASC SUN 1985;2:165-73. 4. La IMuraglia GM, Fischman AJ, Strauss HW. Utility of the iridium Ill-labeled human immunoglobulin G scan for the detection of focal vascular graft infection. J VASC SURC 1989;10:20-8. 5. Bunt TJ. The management of infected grafts in reconstructive surgery. Thorac Cardiovasc Surg 1986;34:265-8.
Aortobifemoral
prosthesis:
a new design
To the Editurs:
The major problem in the surgery of atherosclerotic lesions of the distal aorta and the iliac arteries is the longevity of the restoration.’ This is mostly due to the progressive degradation of the distal circulation and the quality of the initial intervention. The initial intervention itself can crcatc the following functional anomalies: (1) a protusion of the prosthesis and conflicts with the digestive tract as well as with the superior mcscntcric artcry caused by an end-to-side anastomosis at the anterior face of the subrenal aorta; (2) an increase in aortic diameter caused by the lateral implantation of the prosthesis, thereby increasing the parietal tension of the aorta, which can create an
aneurysm;’ (3) turbulent flow at the end-to-side anastomosis site;” (4) competitive Aow between branches of the prosthesis and the stcnoscd iliac axcs4 Although an anatomic restoration done by end-to-end
Fig.
1. The new aortobifcmoral
prosthesis.
anastomosis on the aorta and the femoral arteries associated with the reimplantation of the inferior mcscnteric artery and hypogastric arteries can avoid the above inconveniences, this technique is longer and more difficult to implement and has not been adopted by most surgeons5 Another problem occurs in subrenal aortic aneurysm interventions when they are associated with external iliac artcry stenosis. In these cases the prosthesis is inevitably implanted by end on the subrcnal aorta and by side onto the femoral arteries. The evolution of the lesions along the external
iliac
arteries
threatens
retrograde
hypogastric
perfusion. In view of the technical difficulties and drawbacks listed above, we propose a new, easily implantable prosthesis, where all anastomosis are end to end, and whcrc the perfusion of the hypogastric arteries is preserved in a physiologic direction. This new aortobifemoral prosthesis is made of woven Dacron, and it is constituted by an aortic tube with two lateral anastomosed branches that radiate from the midpoint of the tube. The branches arc anastomosed at a 30-dcgrce angle, and their diameter is half of that of the principal tube (Fig. 1).
