Infected or exposed vascular grafts

• Complete wound healing achieved in 91% (40/44).
• Grafts preserved long-term without reinfection in 37/44.
• All patients survived to 30 days; 1-year mortality 16% (7/44); long-term mortality 41% at a mean of 43 months (reflecting the polymorbid population rather than graft failure).
• Median NPWT duration 33 days (IQR 20–78); median hospital stay 32 days.
• No significant difference in outcome between graft types (prosthetic, vein, biological).

CAT: OCEBM 4 · This is the strongest single argument in the library for graft-preserving NPWT and it is the only one of the fourteen with no industry involvement at all — the disclosure reads, verbatim: 'There were no outside sources of support.' The results, with denominators. Complete wound healing 40/44 (91%). Long-term graft preservation without reinfection 37/44 — But note what that denominator is: 44 minus 7 treatment failures, that is, the proportion of PATIENTS without treatment failure, while only 40 of the 49 NPWT sites involved a graft at all. 37/44 is not a graft-preservation rate. Median NPWT duration 33 days (IQR 20 to 78); median stay 32 days (IQR 20 to 82). All 44 survived 30 days; one-year mortality 7/44 (16%); long-term 18/44 (41%) at a mean 43 months (SD 21), every death but one unrelated to the infection. Amputation 7/44 (16%); reinfection 9/44 (20%), 12% early and 45% late. Major bleeding 1/44 (2%), from the proximal anastomosis of a femorodistal bypass and attributed to erosion of an exposed xenograft; minor bleeding 2/44; thrombosis 1/44. Delivered pressure is the finding this wiki has been getting wrong. Table 2 records a mean negative pressure of 91 mmHg (SD 26) across the series — 92 (26) for early and 87 (29) for late infections, P = 0.69. The evidence page records this study as being in direct conflict with the wiki's own low-pressure graft protocols and quotes the escalation rationale as best effects on graft survival; the paper says best effects on GRANULATION, and the mean pressure actually delivered sits INSIDE the minus 50 to minus 100 mmHg cap of graft protection technique. The predictor analysis cannot be used. At least four odds ratios are reported as significant while their own 95% intervals include 1.0: Staphylococcus aureus and mortality OR 0.12 (0.00 to 1.00), P = 0.031; early infection and reinfection OR 0.17 (0.03 to 1.07), P = 0.030; late infection and reinfection OR 5.73 (0.93 to 39.1), P = 0.030; and reinfection with graft excision OR 5.82 (1.02 to 72.5), P = 0.023 set against reinfection with amputation OR 5.82 (0.63 to 52.30), P = 0.068 — The same point estimate attached to three different comparisons with three different intervals and three different p-values. Two further odds ratios are computed on cells with zero events. Loss to follow-up is never quantified.

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• Graft preservation 81% overall, falling to 64% for synthetic grafts.
• Major bleeding during NPWT 7.1%; local reinfection 6.4%.
• Synthetic graft infection was independently associated with treatment failure (OR 6.1, 95% CI 2.6–14.4).
• Bleeding or pseudoaneurysm as the presenting symptom was independently associated with failure (OR 2.9, 95% CI 1.0–8.2).

CAT: OCEBM 4 · This is the largest series in the library on established perivascular groin infection and it has no control group, so it measures outcomes under NPWT and not the effect of NPWT. Graft preservation 87/108 (80.6%), rounded to 81% in the abstract; synthetic grafts 33/52 (63.5%), rounded to 64%. Note the denominator: the Results text states there were 106 reconstructions with grafts among the 161 groins, while Table 4 computes preservation on 108. The abstract and the body disagree on the headline odds ratio. Synthetic graft infection is printed as OR 6.1 (95% CI 2.6 to 14.4) in the abstract and as OR 6.1 (95% CI 2.6 to 14.2) in both the Results text and Table 5. This wiki has been carrying the abstract value. The second predictor, bleeding or pseudoaneurysm at presentation, is OR 2.9 (95% CI 1.0 to 8.2), p = 0.049 — a lower bound sitting on the null. Treatment failure 33/156 (21.2%), five patients excluded for death unrelated to the infection. Major bleeding is 7.1% on an unprinted denominator. The components, 4.5% in hospital and 2.6% after discharge, reconcile as 7 and 4 events only on a denominator of about 155, not on the 161 cohort, where 11/161 is 6.8%; the paper never states which denominator applies. Local reinfection 6.4% has the same problem. A SECOND DISCORDANCE: the Results text states that critical limb ischaemia was the indication in 63% of patients, while Table 2 records 39.1%; 63% is the proportion of men. Median time to full epithelialisation 60 days (IQR 49 to 83), with 70% healed by 80 days on Kaplan-Meier. 30-day amputation 8/161 (5.0%), one-year 24/161 (14.9%); 30-day mortality 9/161 (5.6%), one-year 25/161 (15.5%). Missing data are declared but not handled: smoking 138/157 with four missing, antibiotic appropriateness 48/146 with fifteen missing. No loss-to-follow-up figure exists. Funding, verbatim: 'This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.' Conflict of interest, verbatim: 'None.' No ethics approval was sought.

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• For open infected groin wounds, NPWT gave healing 47 days shorter and was more cost-effective than alginate dressings in one RCT.
• Across 1 RCT plus 6 observational studies, NPWT-related major bleeding ranged 0–10% and graft preservation 83–100%.
• NPWT with mesh-mediated fascial traction after AAA repair / open abdomen achieved primary fascial closure in 96–100% with graft infection risk 0–7%.
• One retrospective study reported that closed-incision NPWT (ciNPT) reduced SSI from 30% to 6%.

CAT: OCEBM 4 · Certainty has to be assigned claim by claim, because the claims do not share a denominator and the review presents them as though they did. The headline closed-incision figure — Surgical-site infection falling from 30 per cent to 6 per cent — Rests on one retrospective study with a historical control group, and that study is not one of the ten the PRISMA search retrieved. The authors say as much: at the time of writing there was no published RCT and only one retrospective comparative observational study of NPWT over closed incisions in vascular surgery. Start Low for a non-randomised comparison, minus 1 risk of bias (historical controls, no adjustment, single centre), minus 1 imprecision (one study, no interval reported) — VERY LOW. The open-groin claim of healing 47 days shorter and better cost-effectiveness comes from one randomised trial, and it is the senior author's own (Monsen, with Acosta). Start High, minus 1 risk of bias (unblindable, single centre), minus 1 imprecision (a single small trial) — Low. The graft-preservation range of 83 to 100 per cent and the major-bleeding range of 0 to 10 per cent are not effect estimates at all. They are the spread of proportions across seven uncontrolled series with no comparator, so there is no effect in which to have certainty and the range must never be quoted as a benefit. The primary fascial closure rate of 96 to 100 per cent after aortic repair comes from three observational studies, the largest prospective one with 30 patients — Very low, and again single-arm. Indirectness is the understated problem: three of the ten included studies and the EndoVAC series are the authors' own work, so a substantial part of this review is one Swedish group's practice presented as a field.

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• Graft/patch salvage: 61 of 72 (84.7%) in the abstract and Discussion; 70 of 72 (97.2%) in the Results. Native grafts/patches replaced with autogenous vein or silver Dacron in 4 of 17; prosthetic grafts preserved without revision in 48 of 55 (87.3%).
• VAC duration 16 ± 7.7 days; hospital stay 25.3 ± 8.5 days; healing time 24.3 ± 12.5 days.
• Closure: secondary closure 23 (31.9%), meshed split-skin graft 49 (68%).
• Complications during NPWT: fluid retention 2, more analgesia 12 (16.7%), one death (1.3%) from a secondary bleed — native vessel erosion, with VAC in place; the authors judge the device not causal.
• Follow-up 4.3 ± 3.5 years; one patient lost to follow-up.

CAT: OCEBM 4 · START LOW for an uncontrolled series and downgrade for risk of bias and inconsistency: no comparator, so salvage cannot be attributed to VAC as opposed to the debridement, sartorius flap and antibiotics every patient also received; the salvage rate is reported as both 84.7% and 97.2% in the same paper; exclusions remove exactly the patients most at risk (anastomotic bleed, septicaemia, proximal extension); and the one death was a bleed during VAC. VERY LOW. Its value is technical: a described protocol (flap first, foam on the graft body, never on the anastomosis, −125 mmHg continuous, change every 72 h, stop by one month) from a large series.

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• Four core mechanisms of action underpin every indication: (1) reduces tissue oedema; (2) increases granulation tissue formation; (3) increased perfusion as a secondary/later effect; (4) with instillation and dwell time can reduce wound contamination.
• Vascular surgery: high-level evidence supports NPWT for infected vessels and prosthetic vascular grafts — strong recommendation for high-risk surgical patients with a fully exposed, infected prosthetic vascular graft, together with debridement and appropriate antibiotics; continuous suction at lower levels (-50 to -100 mmHg) recommended to avoid bleeding.
• Traumatic/surgical wounds: NPWT is first-line for preoperative wound-bed preparation post-debridement, typically 7-10 days before definitive surgery; strong for open fractures that cannot be closed primarily (used between debridement and reconstruction); caution when tendon/bone exposed; do not use if underlying arterial impairment is not addressed (red).
• Diabetic foot ulcers: first-line post-surgical treatment for DFU once ischaemia is excluded (University of Texas Grade A2/A3); consider for chronic DFU not progressing after 4 weeks; contraindicated where ischaemia is due to concomitant peripheral arterial disease (red).
• Sternal dehiscence: NPWT is the method of choice for post-sternotomy mediastinitis (strong); caution in the haemodynamically unstable patient; the open sternum with exposed vulnerable structures is not an indication (red).
• Abdominal / dehisced abdominal wounds: strong for the open abdomen and for dehisced wounds with intact abdominal wall; NPWT with instillation (NPWTi-d) is effective in reducing infection in the infected open/dehisced abdomen (moderate); do not use if size/severity does not merit it.
• Skin grafts, burns, venous ulcers, pressure injuries, enterocutaneous fistulae: NPWT endorsed for wound-bed optimisation before grafting and intra-operative graft stabilisation; acute burn indications supported but not a substitute for grafting; venous ulcers only if <30% area reduction in 4 weeks and ABPI 0.8-1.2 (contraindicated if ABPI <0.6); NPIAP stage 3/4 pressure injuries until surgical closure (moderate); ECF in selected collapsible/low-output cases only, never in unexplored fistulae.
• Closed incisional NPWT (ciNPT): recommended to decrease wound complications, dehiscence, haematoma/seroma and surgical site infection (strong).
• Contraindications listed: clotting disorders, active non-capillary bleeding post-debridement, exposed organs/vasculature/anastomoses, eschar or dry necrosis, neoplastic tissue, untreated osteomyelitis, non-enteric and unexplored fistulae.

AGREE II: Recommended with modifications — Scope 67% · Stakeholders 56% · Rigour 23% · Clarity 67% · Applicability 46% · Independence 25%

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