Autologous or bovine pericardium for aortic cusp replacement? Histomorphological and biomechanical properties as decision making tools

Background/Introduction

Aortic valve cusp replacement using autologous pericardium is a promising technique. Expected advantages are reduced immune response, proper biomechanics and lower treatment expenses. During surgery decision for preferred pericardium segment is based on visual criteria. Autologous pericardium can be affected by patient's condition and age. Bovine pericardium, also the basic material for aortic valve prostheses, is easy available and carefully pre-examined. In this study, the homogeneity of tissue thickness, elastic modulus, vessel density and ECM components of GA-treated residual pericardia after surgery is compared with bovine pericardia equivalently treated.

Purpose

Aim of the study is the comparison of homogeneity of remaining autologous pericardium after surgical aortic valve replacement with bovine pericardia to evaluate and classify the individual applicability.

Methods

Up to 12 samples of human (n=7) or bovine (n=3) pericardia were analysed. Tissues were treated with 0.6% glutaraldehyde according to surgical protocol. Picrosiriusred- and HE-staining were performed (three edges per separated leaflet). Vessel or collagen content was determined with Zen Blue resp. Fiji software (colour deconvolution plugin, user threshold values). Sample thickness was measured via thickness gauge FD50 before uniaxial tensile testing. Hydroxyproline content was determined and related to dry weight. T-Test or ANOVA were used to test inter-species or intra-individual differences, respectively.

Results

Human pericardia contain with 64.66±3.85% less collagenous fibres compared to bovine pericardia (86.01±1.713%); their vessel density is with 29.46±3.73 mm–2 significantly higher than in bovine samples (12.34±1.636 mm–2). In addition, human pericardia are with 367.7±59.2 μm significantly thinner than bovine (524.4±96.8 μm). Tensile testing (human: 36.00±15.17 MPa; bovine: 41.30±7.767 MPa) also revealed significant differences. With 77.80±11.76 mg/g merely a trend was observed for a lower hydroxyproline content in human samples (bovine 93.16±5.130 mg/g). ANOVA analyses of human pericardia illustrate significant differences for all properties, thus thickness, elastic modulus and hydroxyproline and collagen content between the individual human pericardium samples. In contrast, bovine pericardia showed an intra-individual difference only for the parameter of tissue thickness.

Conclusion

Human and bovine pericardia differ in histological and biomechanical parameters. In contrast to bovine pericardia, individual human pericardia were significantly different in most parameters investigated, leading to the conclusion that autologous materials are critically more heterogeneous than xenogeneic tissues. Vessel density in human pericardium was twofold higher than in bovine pericardia and can result in a higher risk for calcification.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): TU Dresden

Parietal cell/oncocytic gastric carcinoma: systematic review and first-time assessment of HER2 status in two new cases

INTRODUCTION

Parietal cell/oncocytic gastric carcinomas are very rare and various aspects of this group remain unclear. The human epithelial growth factor receptor 2 (HER2) status of these tumours is largely unknown.

METHODS

We performed a systematic electronic search of the literature and clinicopathological presentation of two cases including first-time complete assessment of HER2 status. Thirty-two patients with a mean age of 64.3 years, 87.5% of whom were male, were included in this review.

FINDINGS

Half of the cases were recorded in Asia. Median follow-up was 24 months. There was no predominant site of development, while underlying histological abnormalities were present in 25%. At initial presentation, lymph node involvement was evident in 46.6% while distant metastatic disease was present in 9.3%. Presentation at stage I occurred in 55.6%. Potentially curative surgical/interventional treatment was intended in 90.6%. Recurrence occurred in 6.6%, while death was recorded in 19.2%, with cancer-related deaths reaching 11.5%. The one- and three-year survival rates were 84.2% and 79%, respectively. Our two cases displayed negative HER2 expression.

CONCLUSIONS

This systematic review demonstrates that this group of malignancies is very rare but possibly underdiagnosed. The disease commonly presents at early stage, mainly affecting middle-aged men. The prognosis is generally favourable even in cases of advanced disease. The HER2 expression and its correlation with the outcomes need to be further explored.

Malplacement of a Pacemaker Lead — A Rare Cause for Aortic Valve Endocarditis

Infective endocarditis of native valves following pacemaker implantation is rare but can be associated with serious complications, approaching a mortality of up to 25%. 1 Recent publications report a frequency of pacemaker related endocarditis between 0.5 and 7%. 2 Due to anatomical reasons the tricuspid valve is mostly affected in these patients, with involvement of the left heart valves usually secondary. We report an incidence of native aortic valve endocarditis due to a misplaced pacemaker lead into the left heart.

Clinical course after surgical treatment of active isolated native mitral valve endocarditis

AIM

Isolated mitral valve endocarditis (MVE) forms a particular subgroup within native infective valve endocarditis (NVE). We characterized this particular subgroup and analyzed the course of patients undergoing cardiac surgery.

METHODS

Between 1997 and 2011, 474 patients underwent cardiac surgery at our institution for NVE treatment. Of these, 89 patients (18.8%) suffered from MVE. Valve replacement was undertaken in 84.2% and valve repair in 15.8%. Follow-up was completed with 267 patient years.

RESULTS

A delay between the onset of first symptoms and surgery of 4.7±1.2 weeks was observed. Hence, most patients were in a critical preoperative state characterized by severe sepsis and destruction of the mitral valve. About 19.4% were emergency procedures. The MVE group presented with a higher prevalence of preoperative stroke, atrial fibrillation, coronary artery disease and chronic obstructive pulmonary disease in comparison with remaining NVE cases. MVE was more likely caused by Staphylococcus aureus; Staphylococcus epidermidis and Staphylococcus viridans were less frequent (P<0.01 each). Early mortality (6.7%) was caused by persistent sepsis. ICU stay >7 days and time on artificial ventilation >40 h led to a higher risk of in-hospital death. Five-year survival was 59.6% and affected by extracardiac comorbidities.

CONCLUSION

Isolated MVE was characterized by a long delay before surgery, differences in microbiological findings and a higher prevalence of preoperative strokes in comparison to NVE. Surgery for MVE can be conducted with good clinical results, but mid-term outcome is limited by extracardiac comorbidities.

Coronary artery bypass grafting in octogenarians--outcome with and without extracorporeal circulation

Octogenarians are increasingly considered for coronary artery bypass grafting (CABG), but still represent a high-risk patient group with increased mortality and morbidity. In recent years off-pump surgery has been successfully established in CABG. The avoidance of extracorporeal circulation (ECC) seems to be of particular benefit for this patient group. We retrospectively analyzed our experience with CABG surgery with and without ECC in octogenarians to define the potential benefit of these different approaches in this high-risk group of patients. We analyzed the outcome after isolated CABG of 344 consecutive patients (219 male, 125 female, age: 82 +/- 2.4 years) who were aged 80 or older. Patients were divided into two groups according to the use of ECC. The on-pump group consisted of 237 patients (151 male, 86 female, 82 +/- 2.8 years) and the off-pump group consisted of 107 patients (68 male, 39 female, 82 +/- 1.9 years). The predicted EuroSCORE and EuroSCORE mortality risk were similar for both patient groups. The overall hospital mortality rate was 5.5 % (n = 17): 14 patients (5.9 %) in the on-pump group (n = 237, 100 %) and five patients (4.6 %) in the off-pump group (n = 107, 100 %). The average number of grafts in the on-pump group was 2.8 +/- 0.4 and it was 2.4 +/- 0.6 in the off-pump group ( P = 0.05). Morbidity was comparable in both groups. Significant variables in multivariate regression were preoperative atrial fibrillation ( P = 0.03; RR = 2.7), COPD ( P = 0.0001; RR = 6.5) and prolonged intubation ( P = 0.005; RR = 4.1). Isolated CABG in octogenarians can be performed with good clinical results, although a substantial mortality remains. The results of coronary surgery in this patient group with and without ECC are comparable with respect to mortality and morbidity.