Basic data underlying clinical decisionmaking in vascular surgery

Section Editor--John M. Porter, MD, Portland, Oregon

Arterial and Prosthetic Graft Infection Richard A. Yeager, MD, John M. Porter, MD, Portland, Oregon

Primary arterial infections continue to be one of the most challenging clinical problems encountered by vascular surgeons, and postoperative graft infection one of the most feared complications. As vascular infections present grave risks to life and limb, vascular surgeons must be fully informed concerning prevention, early diagnosis and prompt vigorous treatment. Much new information is available in recent years about arterial infection. New culture techniques have forced us to examine the prospect that a disturbingly high percentage of diseased arteries routinely harbor bacteria. Additionally, chronic intraaneurysmal thrombus is culture-positive in a From the Department of Surgery, Oregon ttealth Sciences University and the Portland Veterans Administration Medical Center, Portland, Oregon. Reprint requests: Richard A. Yeager, MD, Surgical Service lI2P, Portland Veterans Affairs Medical Center, P.O. Box 1034, Portland, Oregon 97207.

significant number of patients. To date the relevance of these findings to subsequent clinical arterial infection remains indeterminate. Without question a host of new imaging techniques has markedly improved our ability to diagnose vascular infections. We have long recognized the role of computed tomographic (CT) scanning in early diagnosis of prosthetic graft infection. Preliminary data suggest magnetic resonance imaging (MRI) may be a remarkable addition in this area. Both the indium-tagged leukocyte and immunoglobulin scans appear promising for early diagnosis. Finally, in the area of treatment, one is faced with many choices. Some of these include preliminary versus delayed extraanatomic bypass, extraanatomic versus in situ graft replacement, and graft excision and remote bypass versus vigorous local care only. We hope vascular surgeons will find a useful summary of information in the enclosed tables (Tables I-XV).

TABLE I.--Incidence and bacteriology of positive cultures from grossly noninfected aneurysm contents or arterial wall

% positive Abdominal aortic aneurysm contents All reported cases (n = 872) Elective Symptomatic (urgent) Ruptured Elective arterial cases (culture technique included mechanical grinding of specimens) Femoral pseudoaneurysms (sonication culture technique)

Bacteriology % of gram-positive isolates that are coagulase-negative % of isolates that are staphylococci gram-positive

References

13 8 12 20 36

82

53

93

69

1-10 2, 7-9 2, 7-9 2, 7-9 10-12

54

100

68

13

485

ARTERIAL AND PROSTHETIC GRAFT INFECTION

486

ANNALS OF VASCULAR SURGERY

TABLE tl.--Relevance of culture results for predicting subsequent prosthetic graft infection* Percentage of reported cases developing subsequent prosthetic graft infection Culture negative Culture positive Abdominal aortic aneurysm cases Elective arterial reconstructions

1% 0%

References

8% 5%

1-5, 7-9 10, 11, 13

*Cultures from grossly noninfected aneurysm contents or arterial wall.

TABLE III.--Prospective randomized studies documenting significant reduction in vascular surgery wound infection rates using intravenous antibiotics Drug (dose)

Dosage interval and duration

References

Cefazolin (1 Cephradine g) Cefuroxime (1.5 g) Methicillin (2 g)

On-call and post-op every 6 hours for 4 doses 1 hour pre-op and every 6 hours for 4 doses On-call and every 8 hours for 3 doses Pre-op at start of general anesthesia and at 8 and 16 hours after first dose

14 15" 16 t t7

At induction of anesthesia and post-op every 6 hours for 3 doses At onset of anesthesia and 2-3 post-op doses

18 19

1 hour before surgery and 4 hours later

20

~)

+

Netilmicin (200 mg) Cephradine (1 g) Cefuroxime (1.5 g) or

Cefotaxim (2 g) Vancomycin (1 g)

*No added benefit with topical antibiotic wound irrigation. tNo added benefit with 3 day regimen.

TABLE VI.--Current bacteriology of primary aortic

prosthetic graft infection*

TABLE IV.--Current reported incidence of prosthetic

graft infection

Insertion site Aortoiliac Aortofemoral Axillofemoral/femorofemoral Femoropopliteal/tibial

Percent graft infection References