A Fibrin-Thrombin Based In Vitro Perfusion System to Study Flow-Related Prosthetic Heart Valves Thrombosis

Prosthetic heart valve (PHV) replacement has increased the survival rate and quality of life for heart valve-diseased patients. However, PHV thrombosis remains a critical problem associated with these procedures. To better understand the PHV flow-related thrombosis problem, appropriate experimental models need to be developed. In this study, we present an in vitro fibrin clot model that mimics clot accumulation in PHVs under relevant hydrodynamic conditions while allowing real-time imaging. We created 3D-printed mechanical aortic valve models that were inserted into a transparent glass aorta model and connected to a system that simulates human aortic flow pulse and pressures. Thrombin was gradually injected into a circulating fibrinogen solution to induce fibrin clot formation, and clot accumulation was quantified via image analysis. The results of valves positioned in a normal versus a tilted configuration showed that clot accumulation correlated with the local flow features and was mainly present in areas of low shear and high residence time, where recirculating flows are dominant, as supported by computational fluid dynamic simulations. Overall, our work suggests that the developed method may provide data on flow-related clot accumulation in PHVs and may contribute to exploring new approaches and valve designs to reduce valve thrombosis.

Survival bias may explain the appearance of the obesity paradox in hip fracture patients

Patients with low-energy hip fractures do not follow the obesity paradox as previously reported. In datasets where injury mechanism is not available, the use of age >50 years (as opposed to commonly used >65 years) as a surrogate for a low-energy hip fracture patients may be a more robust inclusion criterion.  PURPOSE: In elderly patients with a hip fracture, limited data suggests that obese patients counterintuitively have improved survival compared to normal-weight patients. This "obesity paradox" may be the byproduct of selection bias. We hypothesized that the obesity paradox would not apply to elderly hip fracture patients.

METHODS

The National Surgical Quality Improvement Project dataset identified 71,685 hip fracture patients ≥50 years-of-age with complete body mass index (BMI) data that underwent surgery. Patients were stratified into under and over 75-year-old cohorts (n=18,956 and 52,729, respectively). Within each age group, patients were stratified by BMI class and compared with respect to preoperative characteristics and 30-day mortality. Significant univariate characteristics (p<0.1) were included in multivariate analysis to determine the independent effect of obesity class on 30-day mortality (p<0.05).

RESULTS

Multivariate analysis of <75-year-old patients with class-III obesity were more likely to die within 30-days than similarly aged normal-weight patients (OR 1.91, CI 1.06-3.42, p=0.030). Multivariate analysis of ≥75-year-old overweight (OR 0.69, CI 0.62-0.77, p<0.001), class-I obese (OR 0.62, CI 0.51-0.74, p<0.001), or class-II obese (OR=0.69, CI 0.50-0.95, p=0.022) patients were less likely to die within 30-days when compared to similarly aged normal-weight patients.

CONCLUSIONS

Our data suggest that obesity is a risk factor for mortality in low-energy hip fracture patients, but the appearance of the "obesity paradox" in elderly hip fracture patients results from statistical bias that is only evident upon subgroup analysis.

Atypical mycobacterium infection of sternoclavicular joint: A unique case

We report a rare case of atypical Mycobacterium intracellulare infection encountered in a left sternoclavicular joint of an immunocompetent patient. The 34-year-old female patient presented with a one-year history of left sternoclavicular joint pain and swelling. The patient had multiple radiological investigations, which were suspicious for an infective cause. The patient had a biopsy of the joint, which returned showing acid-fast bacilli. The patient consequently received a prolonged course of medical treatment for M. intracellulare.

Upregulated miR-410 is linked to poor prognosis in colorectal cancer

BACKGROUND

Although miR-410 acts as a cancer inducer in colorectal cancer, there is limited data on the clinical implications of miR-410 expression levels in patients. We hypothesized a link between miR-410 expression and its potential clinical values in patients with colorectal cancer.

MATERIAL AND METHODS

120 colorectal cancer tissue specimens and 120 adjacent non-tumour tissues were obtained. Quantification of miR-410 expression levels was determined by, quantitative RT-PCR. Expression was analysed by clinical features.

RESULTS

miR-410 was up-regulated in malignant tissues compared with corresponding normal tissues (P < 0.01), with TNM stage and lymph node metastasis (P = 0.03, P = 0.004, respectively), and with worse overall survival (P = 0.002). Multivariate survival analysis identified it as an independent risk factor for outcome (P = 0.021, HR = 2.19; 95% CI = 1.12-4.25).

CONCLUSION

Compared to normal non-cancerous tissues, miR-410 was overexpressed in tumour tissues and is independently associated with the unfavourable outcome. Levels of MiR-410 might a useful laboratory tool in managing and predicting the prognosis of colorectal cancer.

Cardiac surgery in patients with a porcelain aorta in the era of transcatheter valve implantation

OBJECTIVES

New surgical and perfusion techniques allow the avoidance of deep hypothermia during open aortic arch surgery, which is generally necessary in patients with an unclampable porcelain aorta. The aim of the study was to evaluate operative and long-term results in patients with a porcelain aorta who underwent conventional cardiac surgery using current surgical and perfusion techniques.

METHODS

Between November 2003 and February 2012, 30 consecutive patients (mean age 68 ± 11 years, 10 patients had previous cardiac surgery with use of glue in 5 of them) with porcelain aorta diagnosed by computed tomography and defined as a severe circular calcification of the proximal thoracic aorta were referred for cardiac surgery. All patients underwent conventional surgery with arterial cannulation of the innominate (8) or a carotid artery (22) for arterial return. During mild hypothermic circulatory arrest, unilateral cerebral perfusion through the arterial line was performed for cerebral protection. The valve surgery consisted of aortic, mitral or double valve repair in 23, 3 and 4 cases, respectively. Aortic surgery (17 complete root replacements with valve composite grafts and 22 arch replacements) and coronary revascularization due to coronary heart disease (15) were the most frequent concomitant procedures.

RESULTS

Thirty-day mortality was 3.3% (1 patient died of bowel ischaemia caused by severe stenosis of the celiac and upper mesenteric arteries) and the rate of permanent neurological deficit was 3.3% as well. Two further patients died during the follow-up at age 91 and 82 years, respectively; however, no death was cardiac or valve related. The actuarial survival at 5 years was 87.3 ± 7.2%. There were no cardiac reoperations, new interventions or aortic- or valve-related events noted during the median follow-up of 45 months (range 0.1-106.0).

CONCLUSIONS

Conventional cardiac and aortic surgery offers definitive repair and can be performed safely using current perfusion and operative techniques. Although more invasive, this surgical technique provides mortality and morbidity rates that do not exceed those reported for transcatheter valve implantation. The curative replacement of the pathological proximal aorta, which is one of the most main sources of cerebral embolism, leads to excellent neurological outcome during mid- to long-term follow-up.

Inorganic sulfate metabolism in the very low birthweight infant

The effect of vitamin D supplementation on inorganic sulfate metabolism was examined in very low birth weight (less than 1,500 g) infants at biweekly intervals after birth until 6 weeks of postnatal age. Baseline serum sulfate concentrations were significantly higher in all infants (471 +/- 24 mumol/l, n = 80) than in adults (299 +/- 25 mumol/l, n = 17). In controls, the levels did not change significantly over the ensuing 6 weeks, although serum creatinine declined. Urinary sulfate excretion rose significantly to near adult levels by 2 weeks. Both urine and serum sulfate were correlated with weight gain but not with estimated glomerular filtration rate, suggesting that factors other than renal clearance have a preponderant influence on serum sulfate in these infants. At 6 weeks, the mean serum sulfate in the high-dose group (receiving 2,170 +/- 23 U/day of vitamin D, n = 41) was significantly higher than in controls (receiving 360 +/- 22 U/day, n = 40). In all infants, there was a significant correlation (r = 0.36, p less than 0.001) between serum sulfate and 25(OH)-vitamin D concentrations, but not other analytes or clinical variables, suggesting that vitamin D may be one of the factors modulating sulfate metabolism in the newborn period.

Oculodento-osseous dysplasia: heterogeneity or variable expression?

Oculodento-osseous dysplasia (ODOD) has been recognised in three South African patients from two kindreds of Dutch descent. Their ocular, nasal, dental and digital stigmata resembled those of previously reported cases, but their cranial hyperostosis and mandibular overgrowth were of much greater degree. In addition, the two survivors had serious neurological complications consequent upon spinal cord compression at the base of the skull and calcification of the basal ganglia. Two of the patients were the product of marriages between a pair of brothers and a pair of sisters, who were themselves clinically normal. This situation is best explained by autosomal recessive inheritance. As ODOD is usually transmitted as an autosomal dominant, and in view of the unusual severity of the manifestations in our patients, it is possible that the condition is heterogeneous and that they had a distinct autosomal recessive form of the disorder. The presence of minimal stigmata in the mother and two prior generations of our third patient could be equally well interpreted as representing great variation in phenotypic expression of a single dominant gene or manifestation in a heterozygote for a recessive gene.