One-year hemodynamic comparison of Perimount Magna with St Jude Epic aortic bioprostheses

Introduction

Cardiac surgeons are using more bioprosthetic valves due to the ageing population as well as to improvements that have been made to these implants. We sought to compare the 1-year hemodynamics of two commercially available valves by echocardiographic parameters.

Material and methods

Retrospective review of our institutional database revealed 69 patients who received either Perimount Magna (n = 33) or St Jude Epic (n = 36) valves in the aortic position with no other valve surgery between June 2004 and March 2006. All patients received transthoracic echocardiography at 1 year. Comparisons between groups were made at baseline and at 1-year follow-up. In addition, a pairwise comparison was performed in each patient to determine the change in echocardiographic parameters between baseline and follow-up.

Results

Mean implanted valve size was similar (Magna 24.3 ±2.0 mm vs. Epic 24.1 ±2.2 mm). Pre- and intraoperative patient variables were similar between the two groups. There were lower peak and mean pressure gradients in the Magna group, both at discharge and one year after surgery. This correlated with a larger indexed effective orifice area (Magna 0.8 ±0.2 cm²/m² vs. Epic 0.67 ±0.2 cm²/m², p = 0.02). In spite of these findings, left ventricular mass regression was not different.

Conclusions

These findings suggest that in a series with relatively low indexed effective orifice areas, the peak and mean gradients obtained were acceptable. More clinical follow-up of these patients is required to assess the true impact of prosthesis patient mismatch.     

Risk modeling for ventricular assist device support in post-cardiotomy shock

BackgroundPost-cardiotomy shock (PCS) has a complex etiology. Although treatment with inotrops and intra-aortic balloon pump (IABP) support improves cardiac performance, end-organ injuries are common and lead to prolonged ICU stay, extended hospitalization and increased mortality. Early consideration of mechanical circulatory support may prevent such complications and improve outcome.MethodsBetween January 1997 and January 2002, 321 patients required IABP and inotropic support for PCS following coronary artery bypass grafting (CABG) at our institution. Perioperative variables including age, mixed venous saturation (MVO₂), inotropic requirements and LV function were analyzed using multivariate statistical methods. All explanatory variables with a univariate p value <0.10 were entered into a stepwise logistic regression model to predict hospital mortality. Odds ratios from significant variables (p < 0.05) in the regression model were used to compose a risk score.ResultsOverall hospital mortality was 16%. The independent risk factors for mortality in this population were: MVO₂ < 60% (OR = 3.2), milrinone > 0.5 μg/kg/min (OR = 3.2), age > 75 (OR = 2.7), adrenaline > 0.1 μg/kg/min (OR = 1.5). A 15-point risk score was developed based on the regression model. Hospital mortality in patients with a score >6 was 46% (n = 13/28), 3–6 was 31% (n = 9/29) and <3 was 11% (n = 29/264).ConclusionsA significant proportion of patients with PCS continue to face high mortality despite IABP and inotropic support. Advanced age, heavy inotropic dependency and poor oxygen delivery all predicted increased risk for death. Further investigation is needed to assess whether early institution of VAD support could improve outcome in this high-risk group of patients.     

Pectoralis major flap for head and neck reconstruction in era of free flaps

The aim of this study was to evaluate factors affecting the selection of pectoralis major flap in the era of free tissue reconstruction for post ablative head and neck defects and flap associated complications. The records of patients who underwent various reconstructive procedures between July 2009 and December 2010 were retrospectively analysed. 147 reconstructive procedures including 79 free flaps and 58 pectoralis major flaps were performed. Pectoralis major flap was selected for reconstruction in 21 patients (36%) due to resource constrains, in 12 (20%) patients for associated medical comorbidities, in 11 (19%) undergoing extended/salvage neck dissections, and in 5 patients with vessel depleted neck and free flap failure salvage surgery. None of the flaps was lost, 41% of patients had flap related complications. Most complications were self-limiting and were managed conservatively. Data from this study suggest that pectoralis major flap is a reliable option for head and neck reconstruction and has a major role even in this era of free flaps. The selection of pectoralis major flap over free flap was influenced by patient factors in most cases. Resource constraints remain a major deciding factor in a developing country setting.     

Streptococcal M protein: alpha-helical coiled-coil structure and arrangement on the cell surface.

The conformation and molecular dimensions of purified type 6 streptococcal M proteins establish the close structural relationship of these molecules to tropomyosin. Ultracentrifuge studies reveal that the M molecules exist as stable dimers; circular dichroism spectra indicate that the molecules contain about 70% alpha helix; and fiber x-ray diffraction diagrams show the characteristic reflections of the alpha-helical pattern. Electron microscopic images of M protein shadowed with platinum reveal rod-shaped molecules having the same width as tropomyosin. However, the lengths of the M molecules are about 30% shorter than lengths predicted by assuming a completely alpha-helical molecule. These findings indicate that the structure of the M6 protein is primarily alpha-helical coiled coil. Comparison of the lengths of the fibers on the surface of the streptococcus and the isolated M proteins suggests that each fiber on the cell wall consists of a single M-protein molecule approximately 500 A long. The structure determined for these fimbriae is the first alpha-helical coiled-coil conformation to be demonstrated for bacterial surface projections.     

Laparoscopic pancreatic cystogastrostomy

The purpose of the review was to evaluate the feasibility and outcome of laparoscopic pancreatic cystogastrostomy for operative drainage of symptomatic pancreatic pseudocysts. A retrospective review of all patients who underwent laparoscopic pancreatic cystogastrostomy between June 1997 and July 2001 was performed. Data regarding etiology of pancreatitis, size of pseudocyst, operative time, complications, and pseudocyst recurrence were collected and reported as median values with ranges. Laparoscopic pancreatic cystogastrostomy was attempted in 6 patients. Pseudocyst etiology included gallstone pancreatitis (3), alcohol-induced pancreatitis (2), and post-ERCP pancreatitis (1). The cystogastrostomy was successfully performed laparoscopically in 5 of 6 patients. However, the procedure was converted to open after creation of the cystgastrostomy in 1 of these patients. There were no complications in the cases completed laparoscopically and no deaths in the entire group. No pseudocyst recurrences were observed with a median followup of 44 months (range 4-59 months). Laparoscopic pancreatic cystgastrostomy is a feasible surgical treatment of pancreatic pseudocysts with a resultant low pseudocyst recurrence rate, length of stay, and low morbidity and mortality.     

Anti-inflammatory and recycling properties of an apolipoprotein mimetic peptide,Ac-hE18A-NH2

Apolipoprotein E (apoE) exerts prominent anti-inflammatory effects and undergoes recycling by target cells. We previously reported that the peptide Ac-hE18A-NH₂, composed of the receptor binding domain (LRKLRKRLLR) of apoE covalently linked to the Class A amphipathic peptide 18A, dramatically lowers plasma cholesterol and lipid hydroperoxides and enhances paraoxonase activity in dyslipidemic animal models. The objective of this study was to determine whether this peptide, analogous to apoE, exerts anti-inflammatory effects and undergoes recycling under in vitro conditions. Pulse chase studies using [¹²⁵I]-Ac-hE18A-NH₂ in THP-1 derived macrophages and HepG2 cells showed greater amounts of intact peptide in the cells at later time points indicating recycling of the peptide. Ac-hE18A-NH₂ induced a 2.5-fold increase in preβ-HDL in the conditioned media of HepG2 cells. This effect persisted for 3 days after removal of the peptide from culture medium. Ac-hE18A-NH₂ also induced the secretion of cell surface apoE from THP-1 macrophages. In addition, the peptide increased cholesterol efflux from THP-1 cells by an ABCA1 independent mechanism. Moreover, Ac-hE18A-NH₂ inhibited LPS-induced vascular cell adhesion molecule-1 (VCAM-1) expression, and reduced monocyte adhesion in human umbilical vein endothelial cells (HUVECs). It also reduced the secretion of interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) from THP-1 macrophages even when administered post-LPS and abolished the 18-fold increase in LPS-induced mRNA levels for MCP-1 in THP-1 cells. Taken together, these results suggest that addition of the putative apoE receptor-domain to the Class A amphipathic peptide 18A results in a peptide that, similar to apoE, recycles, thus enabling the potentiation and prolongation of its anti-atherogenic and anti-inflammatory effects. Such a peptide has great potential as a therapeutic agent in the management of atherosclerosis and other inflammatory diseases.     

Aggregatibacter actinomycetemcomitans–Induced Bone Loss and Antibody Response in Three Rat Strains

Background: The aim of this study is to compare the colonization, immunoglobulin (Ig) G response, and alveolar bone loss in Aggregatibacter actinomycetemcomitans (Aa)–inoculated Fawn Hooded Hypertensive (FHH), Dahl Salt‐Sensitive (DSS), and Brown Norway (BN) rats. Methods: Each rat strain was divided into wild‐type Aa‐inoculated and non‐inoculated control groups. Blood taken at 12 weeks after inoculation was assessed for Aa‐specific IgG antibodies by an enzyme‐linked immunosorbent assay. Colonization was assessed 12 weeks postinoculation. Bone loss was estimated by measuring the distance from the cemento‐enamel junction (CEJ) to the alveolar bone crest (ABC) at 20 molar sites. Colonization and antibody levels were compared by using the Student t test. Diseased rats were defined as having two sites per quadrant with CEJ–ABC distances that were significantly greater than the control CEJ–ABC distances. Results: The Aa colonization of FHH rats was significantly higher than in other strains (P <0.05). The Aa‐specific IgG levels in the DSS Aa‐inoculated group were significantly higher than in its control group (P <0.05). Only FHH rats showed Aa disease‐associated bone loss (P = 0.0021). Conclusions: Aa colonized and caused more disease in FHH rats than in the other rat strains. The rat strains each responded differently to the same Aa strain.     

Comparison of a ray-tracing refractometer, autorefractor, and computerized videokeratography in measuring pseudophakic eyes

PURPOSE: To test the accuracy and reliability of the first-generation prototype of Tracey-1, a ray-tracing refractometer. SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. METHODS: The refractive spherical equivalent (SE) and astigmatism measured by Tracey-1, subjective manifest refraction (MR), and autorefraction (AR) (Nidek AR-3300) were compared in 58 pseudophakic eyes of 44 patients with a mean age of 69.95 years +/- 8.6 (SD). The astigmatic values obtained from Tracey-1 and computerized videokeratography were also compared. Astigmatism values were compared using power vector analysis. RESULTS: The mean SEs measured by MR, Tracey, and AR were -0.76 diopter (D) +/- 0.96 (SD) (range 1.00 to -3.00 D), 0.37 +/- 0.64 D (range 1.68 to -1.49 D), and -0.44 +/- 1.13 D (range 1.63 to -3.50 D), respectively. The Pearson correlation coefficients between MR and Tracey values and between MR and AR values were high (r = 0.895 and r = 0.875, respectively; both P < .0001). However, the mean difference between the Tracey and MR values was 1.13 +/- 0.48 D (range 2.45 to -0.06 D) (P < .001). The mean cylindrical differences between MR and Tracey and between MR and AR were 0.03 +/- 0.51 D (range 1.22 to -1.07 D) (P = .709) and -0.30 +/- 0.62 D (range 0.50 to -2.25 D) (P = .003), respectively. Power vector analysis revealed difference vectors of -0.16 x 60 between Tracey and MR and -0.22 x 87 between AR and MR. CONCLUSIONS: Spherical and cylindrical refractive data obtained with the Tracey system correlated well with those derived from MR; however, there was a mean spherical error of approximately 1.10 D. Further work is required to refine the accuracy and range of this device.