Prevention of perioperative vascular prosthetic infection with a novel triple antimicrobial-bonded arterial graft.

OBJECTIVE: Previously, we investigated a locally developed technique of bonding arterial grafts with three antimicrobials to protect against early (within 2 weeks) perioperative bacterial contamination encountered occasionally during aortic graft prosthetic reconstruction. Vascular graft infections are classified by their appearance time (early [<4 months] vs late [>4 months] after graft implantation), degree of incorporation into the surrounding vessel wall, connectivity to the postoperative wound, and extent of graft involvement. In the current phase of testing, we evaluated the ability of our novel triple antimicrobial-bonded graft to prevent infection in the first 8 weeks after implantation. METHODS: In nine Sinclair miniature pigs, we surgically implanted a 6-mm vascular Dacron patch graft in the infrarenal abdominal aorta. Five pigs received grafts chemically bonded with a 60-mg/mL solution of rifampin, minocycline, and chlorhexidine, and four pigs received unbonded grafts. Before implantation, the five bonded grafts and three of the unbonded grafts were immersed for 15 minutes in a 2-mL solution containing 1-2 × 107 colony-forming units (CFUs)/mL of Staphylococcus aureus (ATCC 29213); the fourth unbonded graft served as a control. RESULTS: At week 9, all of the grafts were explanted. All S aureus-inoculated bonded grafts (n = 5) showed no bacterial growth. The unbonded, uninoculated graft (n = 1) showed low-level bacterial growth (<1.2 × 103 CFUs); S cohnii spp urealyticus, but not S aureus, was isolated, which suggested accidental direct perioperative contamination. Two pigs that received S aureus-inoculated, unbonded grafts were euthanized because of severe S aureus infection (<6.56 × 108 CFUs per graft). Results of histopathologic analysis were concordant with the microbiologic findings. Most intergroup differences were observed in the inflammatory infiltrate in the aortic wall at the site of graft implantation. In all pigs that received bonded grafts, Gram staining showed no bacteria. CONCLUSIONS: Our triple-bonded aortic graft prevented perioperative aortic graft infection for at least 8 weeks in a porcine model. The synergistic antimicrobial activity of this graft was sufficient to prevent and/or eradicate infection during that period. Further studies are needed to assess the graft's ability to combat early-onset vascular graft infection for up to 4 months.

A pilot study of a triple antimicrobial-bonded Dacron graft for the prevention of aortic graft infection.

OBJECTIVE: Perioperative infection of an aortic graft is one of the most devastating complications of vascular surgery, with a mortality rate of 10% to 30%. The rate of amputation of the lower limbs is generally >25%, depending on the graft material, the location of the graft and infection, and the bacterial virulence. In vitro studies suggest that an antibiotic-impregnated graft may help prevent perioperative graft infection. In a pilot animal study, we tested a locally developed technique of bonding Dacron aortic grafts with three antimicrobial agents to evaluate the ensuing synergistic preventive effect on direct perioperative bacterial contamination. METHODS: We surgically implanted a 6-mm vascular knitted Dacron graft in the infrarenal abdominal aorta of six Sinclair miniature pigs. Two pigs received unbonded, uninoculated grafts; two received unbonded, inoculated grafts; and two received inoculated grafts that were bonded with chlorhexidine, rifampin, and minocycline. Before implantation, the two bonded grafts and the two unbonded grafts were immersed for 15 minutes in a 2-mL bacterial solution containing 1 to 2 × 10(7) colony-forming units (CFU)/mL of Staphylococcus aureus (ATCC 29213). Two weeks after graft implantation, the pigs were euthanized, and the grafts were surgically excised for clinical, microbiologic, and histopathologic study. RESULTS: The two bonded grafts treated with S aureus showed no bacterial growth upon explant, whereas the two unbonded grafts treated with S aureus had high bacterial counts (6.25 × 10(6) and 1.38 × 10(7) CFU/graft). The two control grafts (unbonded and untreated) showed bacterial growth (1.8 × 10(3) and 7.27 × 10(3) CFU/graft) that presumably reflected direct, accidental perioperative bacterial contamination; S cohnii ssp urealyticus and S chromogenes, but not S aureus, were isolated. The histopathologic and clinical data confirmed the microbiologic findings. Only pigs that received unbonded grafts showed histopathologic evidence of a perigraft abscess. CONCLUSIONS: Our results suggest that bonding aortic grafts with this triple antimicrobial combination is a promising method of reducing graft infection resulting from direct postoperative bacterial contamination for at least 2 weeks. Further studies are needed to explore the ability of this novel graft to combat one of the most feared complications in vascular surgery.

Operative Intercostal Nerve Blocks With Long-Acting Bupivacaine Liposome for Pain Control After Thoracotomy.

BACKGROUND: Postthoracotomy pain is quite intense. Epidural analgesia (EPI) has long been the gold standard but is often associated with hypotension and urinary retention. The recent availability of liposomal bupivacaine formulation (Exparel) stimulated us to use it for multilevel intercostal nerve blocks (IB) injected during open thoracotomy. METHODS: We reviewed the records of 85 patients who had open thoracotomies for lung, pleural, or mediastinal pathologies between March 2010 and December 2013. Clinical variables; pain score; supplemental narcotic utilization on day 1, 2, and 3; postoperative pulmonary complications; and hospital length of stay were compared in the 2 groups. RESULTS: In all, 53 patients in the IB group had similar clinical data compared to 32 in the EPI group. There were statistically significant lower mean pain scores on days 1 and 3, but no significant difference in pain score on day 2. Supplemental narcotic utilization was not different between the 2 groups. There was a significant decrease in pulmonary complications in the IB group (4 of 53) compared to the EPI group (8 of 32).The total length of hospital stay was 7.4 days in the IB group versus 9.3 days in EPI group (p < 0.05). CONCLUSIONS: It appears that intraoperative IB with bupivacaine liposome at 6 levels during thoracotomy provided significantly better pain control in postoperative days 1 and 3, compared to EPI in this retrospective study. This technique is simple, safe, and reproducible. It does not require epidural space invasion, infusion pumps, or another service to comanage the postoperative pain therapy.

Flat-panel versus 64-channel computed tomography for in vivo quantitative characterization of aortic atherosclerotic plaques.

BACKGROUND: Flat-panel computed tomography (FpCT) provides better spatial resolution than 64-channel CT (64-CT) and may improve in vivo quantitative assessment of atherosclerotic plaques. METHODS AND RESULTS: Lesions in 184 aortic histology sections from 6 Watanabe heritable hyperlipidemic rabbits were quantitatively compared with 64-CT (image thickness, 0.625 mm) and FpCT (image thickness, 0.150 mm) images. Images were re-oriented perpendicular to the vessel centerline. For detecting plaque, FpCT and 64-CT were not significantly different (sensitivity, 76% vs 66%; P=NS). Although FpCT was significantly more sensitive (42% vs 0%; P=<0.001) for detecting eccentric lesions, the area under the curve (AUC) for FpCT (0.6) was not significantly different from that for 64-CT (0.45; P=NS). In detecting plaques with ≤ 10% lipid (low attenuation foci), FpCT was significantly more sensitive than 64-CT (24% vs 0.7%; P<0.00) and had a significantly greater AUC (0.6 vs 0.5; P<0.006). Additionally, FpCT was more sensitive (65% vs 0%; P<0.00) in detecting plaques with ≤ 5% calcium (high attenuation foci) but not in detecting branch points. Both FpCT and histology allowed us to detect low-attenuation foci as small as 0.3mm in diameter, whereas 64-CT allowed us to detect only low-attenuation foci ≥ 1.5mm in diameter. CONCLUSIONS: Flat-panel CT seemed to have more potential for quantitatively screening low-risk small atherosclerotic lesions, whereas 64-CT was apparently more useful when imaging established, well-characterized lesions, particularly when measuring the vascular wall thickness in a rabbit model of atherosclerosis.

Total sternal reconstruction using a titanium plate-supported methyl methacrylate sandwich.

We report a case of total sternal reconstruction using a methyl methacrylate polypropylene sandwich secured by using titanium plates. After previously failed attempts to wean the patient from the ventilator, this reconstruction allowed successful separation from ventilatory support in 6 days.