Abdominal aortic aneurysm repair and colonic infarction: a risk factor appraisal

OBJECTIVE: Colonic infarction is a recognized complication of abdominal aortic aneurysm (AAA) surgery. The clinical difficulty in establishing the diagnosis combined with the patient's poor physiological status is usually associated with a fatal outcome. We assessed our experience with this problem to identify a possible risk factor profile for these patients. METHOD: Patients records were identified from the operative logs, intensive care unit, Hospital Inpatient Enquiry system and vascular unit databases over a 6-year period. RESULTS: A total of 405 patients underwent AAA repair during this period; 140 as emergency ruptures. Nine patients were identified from the databases with known colonic infarction (2.2%). One was a woman. The mean age was 70 years. Seven patients had emergency ruptures (5%). Twenty independent risk factors were analysed using univariate and multivariate logistic regression models. Significant risk factors identified by using a multivariate analysis included the nature of the presenting patient, preoperative hypotension, prolonged cross-clamp time, intra-operative ischaemia and postoperative acidosis. Confirmatory diagnosis was made by colonoscopy in eight patients. One patient survived following the salvage surgery. The mean duration of survival was 10.5 days. The overall mortality was 89% of patients. CONCLUSION: In our unit infrarenal AAA repair has a 2.2% rate of colonic infarction. A definitive diagnosis is best made by colonoscopy. A risk factor profile for the development of colonic infarction may be constructed on the basis of specific clinical parameters. Earlier intervention on the basis of this profile may ultimately reduce the current excessive mortality.     

Usefulness of PCR Strategies For Early Diagnosis of Chagas'' Disease Reactivation and Treatment Follow-Up in Heart Transplantation

Heart transplantation (HTx) is a useful therapy for end‐stage Chaga? cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow‐up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL‐DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA‐PCR was positive 38–85 days before reactivation, whereas SLDNA‐PCR became positive only 7–21 days later, revealing post‐HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.     

Mechanical Testing of Seven Fixation Methods for Generation of Compression Across a Midtarsal Osteotomy: A Comparison of Internal and External Fixation Devices

The purpose of this study was to assess 7 methods of fixation for a midtarsal osteotomy. Polyurethane foam models (N = 6) and cadaver specimens (N = 4-7) were used to examine the force generated by the different constructs of fixation. A midtarsal osteotomy was performed on each specimen in the test groups. The osteotomies were fixated either with 2 parallel 0.062-in Kirschner wires and 40-mm-long, 4-mm partially threaded, cancellous, cannulated titanium screws, an external ring fixator (frame), a frame with wires tensioned (tension), a frame with wires tensioned and compressed toward the osteotomy (tension and compression), a frame with tension, compression, and parallel Kirschner wires, or a frame with tension, compression, and two 4.0 cannulated parallel screws, respectively. Each model was fixated, and the force generated by the construct across the osteotomy was recorded via the use of pressure-sensitive film. Statistical analysis of the data in the polyurethane foam group determined that the use of frame with tension, compression, and two 4.0 parallel cannulated screws was statistically superior to 1) frame, 2) frame with tension, 3) 2 parallel Kirschner wires, 4) two 4.0 cannulated parallel screws, and 5) frame with tension and compression. A cadaver study determined that the frame with tension, compression, and 2 parallel Kirschner wires was statistically superior to 1) frame and 2) two parallel Kirschner wires. These findings suggest that there is a difference in the force generated by the type of fixation construct across a midtarsal osteotomy.