autohaem: 3D printed devices for automated preparation of blood smears.

The process of making blood smears is common in both research and clinical settings for investigating the health of blood cells and the presence of blood-borne parasites. It is very often carried out manually. We focus here on smears for malaria diagnosis and research, which are frequently analyzed by optical microscopy and require a high quality. Automating the smear preparation promises to increase throughput and to improve the quality and consistency of the smears. We present here two devices (manual and motorized) designed to aid in the making of blood smears. These are fully documented, open-source hardware, and an important principle was to make them easily fabricated locally anywhere. Designs and assembly instructions are freely available under an open license. We also describe an image analysis pipeline for characterizing the quality of smears and use it to optimize the settings and tunable parameters in the two devices. The devices perform as well as expert human operators while not requiring a trained operator and offering potential advantages in reproducibility and standardization across facilities.

Use of Omniflow® II in Infected Vascular Grafts with Femoral Anastomotic Dehiscence.

BACKGROUND: Vascular graft infection with anastomotic dehiscence requires immediate surgical intervention to preserve life and limb. We present our experience of using the Omniflow® II biosynthetic vascular prosthesis (LeMaitre Vascular) in the emergency repair of vascular graft dehiscence at the femoral anastomosis. METHODS: A retrospective review of consecutive patients presenting with femoral anastomotic dehiscence in a single centre was conducted. All patients were revascularized using an in situ Omniflow II graft. Patient demographics, affected graft type, microbiology, and antibiotic regimes were documented. Primary outcome measures were limb salvage, patency rates, and mortality. RESULTS: Five patients presented with acute femoral false aneurysm and four of five with significant hemorrhage. Infected grafts included one aortobifemoral, two femoral crossover, one axillobifemoral, and one infrainguinal reversed vein graft. All were revascularized with an in situ Omniflow II graft following the excision of the infected graft material. The median followup was 50 months. Limb salvage was achieved in 8 of 9 threatened limbs, and none required further intervention for re-infection. One graft occluded at 5 months. Two of five patients died during followup (one at 12 months, one at 50 months). CONCLUSIONS: Omniflow II provides a useful "off-the-shelf" conduit for the urgent revascularization of infected femoral dehiscence.

Markers of inflammation in men with small abdominal aortic aneurysm.

BACKGROUND: Markers of inflammation and fibrin turnover are elevated in individuals with a large (>55 mm) abdominal aortic aneurysm (AAA). Fibrin degradation generates D-dimer, known to possess multiple proinflammatory effects, and levels are elevated during early AAA development. This study characterized the plasma inflammatory response during early AAA pathogenesis to determine the effect of D-dimer levels. METHODS: The study compared 75 men with a small AAA (range, 30-54 mm) with 90 age-, sex-, and race-matched controls. Plasma interleukin-6 (IL-6), complement C3, high-sensitivity C-reactive protein (hsCRP), fibrinogen, and D-dimer levels were measured. RESULTS: Mean levels of fibrinogen (2.92 vs 2.59 g/L; P = .003), hsCRP (2.07 vs 1.29 ng/mL; P = .005), and D-dimer (346.7 vs 120.2 ng/mL; P < .001) were higher in men with a small AAA. These markers correlated with maximum aortic diameter determined by ultrasound imaging. On multivariate analysis, D-dimer levels were elevated in AAA individuals independent of smoking, cardiovascular disease (CVD), atherosclerotic risk factors, and inflammatory parameters. Fibrinogen and hsCRP levels remained elevated after adjustment for these covariates but lost significance when D-dimer was added to the model. CONCLUSION: C-reactive protein and D-dimer levels are elevated during early AAA development. D-dimer levels are most tightly associated with AAA status, however, and may mediate the observed elevation in acute-phase reactants.

Altered fibrin clot structure and function in the healthy first-degree relatives of subjects with intermittent claudication.

OBJECTIVE: Studies report clustering of cardiovascular risk factors and increased cardiovascular events in healthy first-degree relatives (FDR) of subjects with intermittent claudication (IC). Family history is an independent risk factor in coronary artery disease but the role of genetic factors is undefined in peripheral arterial disease. The fibrin clot is the final product of the atherothrombotic process and is subject to genetic influence. We proposed that healthy male FDR of subjects with IC possess abnormalities in their fibrin clots. METHODS: This was a case-control family study. The FDR were recruited from claudicants attending vascular surgery out-patient clinics with the control subjects being recruited from the local primary care register. A total of 106 white European male FDR of male subjects with IC were age matched with 107 white European male control subjects from an identical geographic area. The control subjects had no FDR with a history of symptomatic cardiovascular disease, and subjects from both groups were free from a personal history of symptomatic cardiovascular disease or diabetes mellitus. Ex vivo assays for fibrin clot permeation, fiber thickness, factor XIII cross-linking activity, and fibrinolysis were performed on the plasma of the above subjects. In addition, linear regression analysis was undertaken to determine factors associated with clot parameters. RESULTS: For controls and FDR, respectively, fiber thickness by turbidity was 0.75 (0.67-0.93) vs 0.86 (0.75-0.98) (P < .001), and FXIII cross-linking activity was 105% (87-141) vs 133% (103-155) (P < .001). On confocal microscopy, fibers measured 315.8 (307.0-324.6) vs 405.1 (397.6-412.6) nm (P < .001), and lysis front velocity was 12.66 (6.38-18.94) vs 4.83 (2.50-7.17), mum/min (P = .018). Linear regression analysis revealed cholesterol was associated with changes in certain clot parameters. CONCLUSION: The healthy FDR of subjects with IC produce clots which have thicker fibers, increased cross-linking, and resistance to fibrinolysis when compared to controls. This supports the potential genetic basis of peripheral arterial disease and highlights that cholesterol may contribute to this abnormal structure. This suggests that the FDR of subjects with IC, an apparently healthy sub-group of the population, have an elevated cardiovascular risk associated with abnormalities in their clot structure.

Multiple peripheral pneumococcal mycotic aneurysms without aortic involvement: a unique case confirmed with the novel use of a molecular diagnostic technique.

Mycotic aneurysms confer a high morbidity and mortality. Streptococcus pneumoniae aneurysms usually affect the aorta and are rare, although bacterial cultures from aneurysm tissue may be difficult following prior antimicrobial therapy. We report a unique case of mycotic femoral and popliteal artery aneurysms following pneumococcal pneumonia and meningitis, which were managed by resection, revascularization with autologous vein, and intravenous benzylpenicillin. Although blood and aneurysm sac cultures were negative, arterial wall S pneumoniae DNA was detected by polymerase chain reaction (PCR). Appropriate molecular diagnostic techniques can facilitate diagnosis and direct antimicrobial therapy; an important consideration with increasing antimicrobial resistance.

Atherothrombotic risk factor clustering in healthy male relatives of male patients with intermittent claudication.

OBJECTIVE: Family history is an independent risk factor for premature acute myocardial infarction; in contrast, familial risk for peripheral arterial disease (PAD) has yet to be determined. Elevated levels of hemostatic proteins are consistently predictive for cardiovascular risk in "healthy" subjects, and may cluster with underlying insulin resistance. Atherothrombotic risk factor clustering occurs in first-degree relatives of subjects with coronary artery disease and type 2 diabetes. These may contribute to the enhanced cardiovascular risk in these subjects, and we hypothesised that familial clustering may occur in PAD. The objective of this study was to measure atherothrombotic risk factors in healthy male first-degree relatives of men with intermittent claudication, with emphasis on thrombotic risk. METHODS: One hundred sixty-five healthy male first-degree relatives were compared with control subjects matched for age, sex, and race (n = 165), free from a personal or family history of premature cardiovascular disease. Primary outcome measures were fibrinogen, von Willebrand factor, factor VII clotting activity (FVII:C), and factor XIII levels. Atherosclerotic risk factors were measured, and subjects were genotyped for common functional polymorphisms (factor VII r353q and fibrinogen B beta-455). RESULTS: Relatives had higher mean levels of fibrinogen (3.04 vs 2.89 g/L; P = .021), FVII:C (117% vs 104%; P = .000), factor XIII B subunit (1.11 vs 1.01 IU/mL; P = .000), and complex (A 2 B 2 ; 1.18 vs 1.11 IU/mL; P = .021). At multivariate analysis the association between relative status and fibrinogen, FVII:C, and factor XIII B subunit levels were independent of other variables. CONCLUSIONS: The healthy male relatives of men with PAD have elevated levels of fibrinogen, factor VII, and factor XIII. Our results support the existence of thrombotic risk factor clustering in this population at "high risk."

Persistent sciatic vessels, varicose veins, and lower limb hypertrophy: an unusual case or discrete clinical syndrome?

Persistent sciatic artery is a rare congenital anomaly with a high incidence rate of aneurysmal degeneration and risk of thromboembolization or rupture. Despite a number of recognized associations, the presence of coexistent venous anomalies is extremely rare. We present the case of a 27-year-old woman with atypical left-sided varicose veins and soft tissue hypertrophy. Imaging showed persistence of both sciatic artery and vein. Whether these anomalies are an incidental finding or represent a discrete clinical syndrome remains unclear. We emphasize that unusual distribution varicose veins may be associated with underlying persistent sciatic vessels and recommend formal duplex scan assessment for these anomalies.

Type II endoleaks: predictable, preventable, and sometimes treatable?

OBJECTIVE: The purpose of this study was to evaluate the effect of preoperative coil embolization of lumbar and inferior mesenteric arteries on the incidence of type II endoleak after endovascular abdominal aortic aneurysm repair. METHODS: The subjects were consecutive patients who underwent EVAR between January 1996 and January 2001. Patent aortic side branches were identified with preprocedural spiral computed tomographic scanning and calibrated angiography. Coil embolization was performed before EVAR. Patients were followed up with plain radiographs and ultrasound and dual phase spiral computed tomographic scans. Digital subtraction angiography was performed when endoleak was suspected. The outcome measures were the incidence of type II endoleaks and changes in maximum aortic sac diameter (Dmax). RESULTS: Forty patients underwent EVAR, with a median duration of follow-up of 24 months (range, 3 to 48 months). Before surgery, the inferior mesenteric artery was patent in 16 patients (45%) and the lumbar arteries in 21 patients (53%). Inferior mesenteric artery embolization was successful in 13 of 16 patients (81%). Lumbar embolization was attempted in 13 patients and was successful in eight (62%). During EVAR, successful sac exclusion was achieved in 38 patients (95%). None of the patients who underwent embolization before EVAR had type II endoleak develop, eight of 13 patients (62%) with patent lumbar arteries had endoleaks develop (P =.006), and three of these patients subsequently underwent successful coil embolization. Type II endoleak was associated with a 2.0-mm median increase in Dmax (P =.045). A 3.0-mm median reduction in Dmax was seen in the absence of type II endoleak (P =.002). CONCLUSION: Type II endoleaks are predictable, preventable, and sometimes treatable. Significant sac shrinkage occurs in the absence of lumbar endoleak but not in the presence of type II endoleak.