Evaluation of select biocompatible markers for labelling peripheral nerves on 11.7 T MRI.

BACKGROUND: Peripheral nerve injury is often followed by a highly variable recovery process with respect to both rapidity and efficacy. Identifying post-nerve injury phenomena is key to assessing the merit and timing of surgery as well as to tracking nerve recovery postoperatively. Diffusion Tensor Imaging (DTI) has been investigated in the clinical and research settings as a noninvasive technique to both assess and monitor each patient's unique case of peripheral nerve damage. NEW METHOD: We identify a MRI-suitable marker for tracking the exact site of either nerve injury or coaptation following surgical repair to aid with DTI analysis. RESULTS: Due to artefact and disruption of tractography, silver wire and microvascular clips were not suitable markers. AxoGuard®, 4-0 vicryl suture, and 10-0 polyamide suture, although detectable, did not produce a signal easily distinguished from post-surgical changes. Silicone was easily identifiable and stable in both the acute and delayed time points, exhibited negligible impact on DTI parameters, and possessed geometry to prevent nerve strangulation. COMPARISON WITH EXISTING METHOD: Prior studies have not assessed the efficacy of other markers nor have they assessed silicone for potential artefact with DTI parameter analysis. Furthermore, this work demonstrates the reliability and compatibility of silicone in the delayed postoperative time period and includes its unique imaging appearance on high-resolution 11.7 MRI. CONCLUSION: Semi-cylindrical silicone tubing can be used as a safe, reliable, and readily available radiological marker to visualize and monitor a region of interest on a rodent's peripheral nerve for aiding assessments with diffusion tensor imaging.

Surgical management of infective endocarditis: early and long-term mortality analysis. single-center experience and brief literature review.

INTRODUCTION: In this study we evaluated factors that affect the early and long-term postoperative outcomes of patients with infective endocarditis. METHODS: We retrospectively reviewed 94 patients (68 male, 26 female, mean age 58.3 ± 13.1 years, range 20-85 years) with proven infective native (n=85) or prosthetic valve (n=9) endocarditis who underwent heart valve surgery between September 1997 and December 2007. Fifty-four patients (57.4%) underwent aortic, 28 (29.8%) mitral, 3 (3.2%) tricuspid, 8 (8.5%) double, and one patient (1%) triple valve surgery. In 75.5% of the procedures we implanted mechanical valves, in 13.8% biological prostheses, and 10.7% were reconstructive or other procedures. Midterm follow up was 100% complete with a cumulative duration of 545 patient-years (maximum 12 years). RESULTS: Overall hospital mortality (30 days) was 8.5% (n=8). Causes of early mortality were low cardiac output syndrome in 2 cases, sepsis with multiple organ failure in 5 cases, and intracerebral bleeding in one patient. Development of postoperative low cardiac output syndrome (p=0.01) was identified as an independent predictor of early mortality. Overall late mortality was 25.6% (n=22) with a cumulative rate of 4.03% per patient-year. Causes of late death were predominantly of extracardiac origin. Kaplan-Meier survival analysis revealed a cumulative survival rate at 12 years of 57.2%. Cox regression analysis identified diabetes mellitus (p=0.016) and postoperative low cardiac output syndrome (p=0.03) as independent late mortality factors. CONCLUSIONS: Heart valve surgery in patients with infective endocarditis is associated with increased but acceptable early and long-term mortality. The mid-term prognosis is similar to that of patients undergoing elective valve replacement surgery.

Infective endocarditis complicated by paravalvular abscess: a surgical challenge. An 11-year single center experience.

AIM: To evaluate the impact of paravalvular abscess in the surgical management and outcome of infective endocarditis. METHODS: Retrospective review of 35 patients with paravalvular abscess due to active endocarditis operated on at 1 institution from September 1996-August 2007. Patients' mean age was 59.4 +/- 12.1 years; 80% were men. 31 patients suffered from native- and 4 from prosthetic valve endocarditis. In 23 cases the affected valve was the aortic, in 7 cases the mitral, in 4 cases both (mitral and aortic), and in 1 patient the tricuspid; no abscess presence was noticed by pulmonal annuluses. Surgical procedures included radical lesion-resection as well as reconstruction of the annulus with pericardial patches. Most of the patients were preoperatively in New York Heart Association (NYHA)-class III-IV. Follow-up was 100% complete with a maximum of 11.25 years. RESULTS: Early mortality (30 days) was 11.4% (n = 4). The 11-year overall survival rate was 68.7 +/- 9% (76.1% for aortic valve patients and 26.9% for mitral valve patients (P = .15). With regard to the type of prosthetic devices, the survival rates at 11.25 years were 74.2% for mechanical, 80% for biological, and 45.6% for other/reconstructive (P = .6). There were no episodes of recurrent endocarditis; hence freedom of recurrent endocarditis at 11 years was 100%. Causative microorganisms were approximately 30% Staphylococci, and MRSA seems to induce more frequent destructive lesions like paravalvular abscess. CONCLUSIONS: Considering the severity of the onset, a radical surgical treatment delivers acceptable long-term results by acceptable operative mortality. The choice of the prosthetic device seems not to be influential in long-term survival and morbidity.