Transcatheter aortic valve implantation (TAVI) for treatment of aortic valve stenosis: an evidence update

BACKGROUND

One-year mortality outcomes in the PARTNER trial showed that transcatheter aortic valve implantation (TAVI) was noninferior to surgical aortic valve replacement (sAVR) in patients who were eligible for sAVR (cohort A), and superior to standard treatment in patients who were ineligible for sAVR (cohort B).

OBJECTIVE

To update a previous report on the safety, effectiveness, and cost-effectiveness of TAVI, published in 2012.

DATA SOURCES

A literature search was performed on September 11, 2012, using OVID MEDLINE, OVID MEDLINE In-Process and Other Non-Indexed Citations, OVID EMBASE, EBSCO Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Wiley Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published from January 1, 2011, until September 11, 2012.

REVIEW METHODS

Randomized controlled trials investigating TAVI in comparison to sAVR or standard treatment were included for analysis. Results were summarized descriptively.

RESULTS

At 2-year follow-up, mortality in cohort A was similar between the TAVI and sAVR groups. Rates of stroke/transient ischemic attack, major vascular complications, and moderate/severe paravalvular aortic regurgitation were significantly higher in the TAVI group, but rate of major bleeding was significantly higher in the sAVR group. Mortality in cohort B was significantly lower with transfemoral (TF) TAVI than with standard treatment, but rate of stroke was significantly higher with TF TAVI. TF TAVI resulted in a more rapid improvement in quality of life scores than sAVR, but this difference was not sustained at 6 and 12 months. Patients who underwent transapical TAVI did not have a greater early improvement in quality of life compared to sAVR patients. Compared to standard treatment, TF TAVI resulted in a greater improvement in quality of life scores at all time points. Incremental cost-effectiveness ratios were in favour of TAVI for inoperable patients in the base-case analysis, but varied widely for operable patients.

CONCLUSIONS

The findings of the 2-year follow-up with respect to mortality and adverse events were consistent with those of the 1-year follow-up. TAVI was also associated with improvement in quality of life, although results varied by cohort. Consistent with the 2012 report, TAVI may be cost-effective for patients who are not candidates for surgery.

Effect of Compatibilizer Distribution on Thermal and Rheological Properties of Gelatinized Starch/Biodegradable Polyesters Blends

Thermal and rheological properties of various blends of gelatinized starch and biodegradable polyester, polycaprolactone (PCL) or poly(butylene succinate adipate) (PBSA), were studied by DSC, TGA and rheometry. Methylenediphenyl diisocyanate (MDI) was used as a compatibilizer and was distributed in different phases through controlled processing. The addition of MDI showed a stronger effect on thermal and rheological properties when it was mainly distributed in the polyester phase prior to blending. Starch was shown to increase the shear viscosity of both types of polyesters. The two blends, starch/PCL and starch/PBSA, showed a similar pattern of a power law dependence of viscosity on shear rate. MDI was shown to enhance the effect of starch on the melting and decomposition temperatures, especially when distributed in the polyester phase.

Clinical utility of serum matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 concentrations in the assessment of liver fibrosis due to chronic hepatitis B

OBJECTIVE

To explore the relationships between serum concentrations of tissue inhibitor of metalloproteinase-2 (TIMP-2) and matrix metalloproteinase-2 (MMP-2), and severity of liver fibrosis in chronic hepatitis B.

METHODS

A total of 101 patients with hepatitis B and 54 healthy control subjects were consecutively enrolled. Serum MMP-2 and TIMP-2 were quantified by enzyme-linked immunosorbent assay.

RESULTS

Serum MMP-2 concentrations in patients with stage F2 - F4 fibrosis were significantly higher than in patients with stage F0 - F1 fibrosis and control subjects, but no significant difference was found between patients with stage F0 - F1 fibrosis and control subjects. Significant differences in serum TIMP-2 concentrations were found between patients with stages F2 - F4 and F0 - F1 fibrosis, and between stages F0 - F1 fibrosis and healthy control subjects. Areas under the receiver operating characteristic curves of serum TIMP-2 and MMP-2 for predicting clinically significant fibrosis (stage F2 - F4) were 0.899 and 0.770, respectively.

CONCLUSION

Serum TIMP-2 and MMP-2 assessment may represent a valuable noninvasive diagnostic test for liver fibrosis in hepatitis B.

Incidence and risk factors for progressive multifocal leukoencephalopathy among patients with selected rheumatic diseases

OBJECTIVE

To ascertain the incidence of progressive multifocal leukoencephalopathy (PML) in patients with selected rheumatic diseases, to describe the characteristics of PML cases occurring in this setting, and to evaluate the extent to which such cases occurred in the context of biologic therapies such as rituximab or tumor necrosis factor antagonists.

METHODS

We conducted a large population-based study to describe the incidence and risk factors for PML among patients with rheumatoid arthritis, psoriatic arthritis, psoriasis, juvenile idiopathic arthritis, inflammatory bowel disease, and ankylosing spondylitis using national inpatient and outpatient administrative data from the entire Center for Medicare and Medicaid Services from 2000-2009. Suspected PML cases were identified using hospital discharge diagnosis codes. Risk factors for PML were evaluated using outpatient data ≥6 months prior to PML diagnosis.

RESULTS

Among 2,030,578 patients with autoimmune diseases of interest, a total of 53 PML cases were identified (2.6 per 100,000 patients). Most PML cases had human immunodeficiency virus (HIV) and/or cancer. Nine PML cases had evidence for biologic use prior to PML hospitalization, of which 3 had neither HIV nor malignancy and were exposed to biologics within 12 (rituximab) or 6 months (all other biologics) prior to PML diagnosis. PML occurred at an estimated incidence of 0.2 per 100,000 patients with autoimmune diseases who did not have HIV or malignancy.

CONCLUSION

PML occurs at a very low incidence among patients with rheumatic diseases but can occur even in the absence of HIV or malignancy.

Transcatheter aortic valve implantation (TAVI) for treatment of aortic valve stenosis: an evidence-based Analysis (part B)

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical aortic valve replacement (sAVR) for patients at high risk for surgery.

OBJECTIVE

To evaluate the safety, effectiveness, and cost-effectiveness of TAVI for treatment of aortic valve stenosis in symptomatic older adults.

REVIEW METHODS

A literature search was performed on September 6, 2011, for studies published from January 1, 2007, to September 6, 2011. A combined decision tree and Markov model was developed to compare costs, life years, and quality-adjusted life-years (QALYs) of all treatment options in their respective patient populations over a 20-year time horizon.

RESULTS

Two studies from the PARTNER trial were identified. The first study compared TAVI to sAVR in patients who were candidates for sAVR. The second study compared TAVI to standard treatment in patients who were not eligible for sAVR. The first study showed that TAVI and sAVR had similar mortality rates at 1 year. The second study showed a significant improvement in patient survival in those undergoing TAVI. However, in both studies, the TAVI group had significantly higher rates of stroke/transient ischemic attack, and major vascular complications. Rates of major bleeding were significantly higher in sAVR group in the first study and significantly higher in TAVI group in the second study. The base-case cost-effectiveness of TAVI was $48,912 per QALY, but the incremental cost-effectiveness ratio ranged from $36,000 to $291,000 per QALY depending on the assumptions made in the longer-term prediction portion of the model (i.e., beyond the follow-up period of the PARTNER trial).

CONCLUSIONS

TAVI improves survival in patients who cannot undergo surgery. For those who are candidates for surgery, TAVI has a mortality rate similar to sAVR, but it is associated with significant adverse effects. TAVI may be cost-effective for patients who cannot undergo surgery, but is not cost-effective for patients who can.

A novel monoclonal antibody against human CD80 and its immune protection in a mouse lupus-like disease

Blockade of the interactions between CD28/CTLA-4 and their ligands, CD80 (B7, B7.1)/CD86 (B70, B7.2), is an attractive means to induce antigen-specific peripheral tolerance in autoimmune disease and organ transplantation. In this study, we generated and characterized a monoclonal antibody (Clone 4E5) against human CD80. 4E5 could recognize both human and mouse CD80 and suppress mixed lymphocyte reaction in vitro. To investigate their potency for clinical use, we further administrated 4E5 to a mouse lupus-like disease model (C57BL/J6) induced by Pristane. 4E5 could inhibit the immune response and attenuate the severity of lupus-like disease. The data showed 4E5 function and suggested that blockade of CD80/CD28 co-stimulatory signal pathway with 4E5 is a promising strategy to decelerate the progression of lupus-like disease and other autoimmune diseases.

Joint analysis of the Cs2 a3Σu+ and 1g (3(3)Π1g) states

Sets of experimental data on the Cs(2) a(3)Σ(u)(+) and 1(g) (3(3)Π(1g)) states, including the bound-bound and bound-free fluorescence spectra, are analyzed simultaneously to produce the potential energy curves of both states in the form of the Morse long range multiparameter function. The attractive branch of the a(3)Σ(u)(+) state potential is improved relative to the one reported in our earlier work [F. Xie, V. B. Sovkov, A. M. Lyyra, D. Li, S. Ingram, J. Bai, V. S. Ivanov, S. Magnier, and L. Li, J. Chem. Phys. 130, 051102 (2009)], in which the data on this state alone were analyzed. Besides, the new potential of this state also includes the repulsive branch in the range spanned by the bound-free fluorescence spectra. We have not found experimental evidence of the double minimum character of the 3(3)Π(1g) state potential, predicted by ab initio calculations, at least up to v = 8. This fact testifies that the upper state observed is better described by the Hund coupling case (c), in which the case (a) electronic basis states are intermixed by the strong spin-orbit interaction.

An in vitro study of two GAG-like marine polysaccharides incorporated into injectable hydrogels for bone and cartilage tissue engineering

Natural polysaccharides are attractive compounds with which to build scaffolds for bone and cartilage tissue engineering. Here we tested two non-standard ones, HE800 and GY785, for the two-dimensional (2-D) and three-dimensional (3-D) culture of osteoblasts (MC3T3-E1) and chondrocytes (C28/I2). These two glycosaminoglycan-like marine exopolysaccharides were incorporated into an injectable silylated hydroxypropylmethylcellulose-based hydrogel (Si-HPMC) that has already shown its suitability for bone and cartilage tissue engineering. Results showed that, similarly to hyaluronic acid (HA) (the control), HE800 and GY785 significantly improved the mechanical properties of the Si-HPMC hydrogel and induced the attachment of MC3T3-E1 and C28/I2 cells when these were cultured on top of the scaffolds. Si-HPMC hydrogel containing 0.67% HE800 exhibited the highest compressive modulus (11kPa) and allowed the best cell dispersion, especially of MC3T3-E1 cells. However, these cells did not survive when cultured in 3-D within hydrogels containing HE800, in contrast to C28/I2 cells. The latter proliferated in the microenvironment or concentrically depending on the nature of the hydrogel. Among all the constructs tested the Si-HPMC hydrogels containing 0.34% HE800 or 0.67% GY785 or 0.67% HA presented the most interesting features for cartilage tissue engineering applications, since they offered the highest compressive modulus (9.5-11kPa) while supporting the proliferation of chondrocytes.

Genetic deletion of Nogo/Rtn4 ameliorates behavioral and neuropathological outcomes in amyloid precursor protein transgenic mice

The cognitive impairment in Alzheimer's disease (AD) is associated with synaptic loss, neuritic sprouting and altered neuroplasticity. Compensatory neuritic sprouting might be beneficial, while aberrant sprouting could contribute to the neurodegenerative process. Nogo (or Rtn4) is a major myelin-derived inhibitor of axonal sprouting in adult CNS. Recent evidence has implicated both the Reticulon family of proteins and a receptor for Nogo, NgR, in reducing amyloid-beta production, a key step in AD pathogenesis. To test the hypothesis that Nogo, as an inhibitor of axonal sprouting, modulates disease progression in a mouse model of AD, we introduced an APP transgene (a human APP minigene carrying the Swedish and Indiana mutations under the platelet-derived growth factor subunit B (PDGFB) promoter) into a Nogo null background and characterized the behavioral and neuropathological consequences. We found that deleting Nogo ameliorates learning and memory deficits of APP transgenic mice in the Morris water maze at an early/intermediate stage of the disease. Furthermore, deleting Nogo restored the expression levels of markers for synapto-dendritic complexity and axonal sprouting including synaptophysin, MAP2, GAP43 and neurofilament that are otherwise reduced in APP transgenic mice. Other aspects of disease progression including neuronal loss, astrogliosis, microgliosis and, importantly, Abeta levels and amyloid deposits were not significantly altered by Nogo deletion. These data support the hypothesis that Nogo-mediated inhibition of neuritic sprouting contributes to the disease progression in an APP transgenic model of AD in a way that is mechanistically distinct from what has been proposed for Rtn3 or NgR.

Secretory expression of insulin precursor in pichia pastoris and simple procedure for producing recombinant human insulin

In this work, Pichia pastoris was applied to produce human insulin by a simple procedure. The synthesized insulin precursor (ILP) gene was inserted into pPIC9K to obtain secretary expression plasmid pPIC9K/ILP. Pichia pastoris GS115 was transformed by pPIC9K/ILP and the high expresser was screened. In a 16 L fermentor, the insulin precursor production was 3.6 g/L. Insulin precursor, purified by one-step chromatography, was converted into human insulin by transpeptidation. The yield of the processing procedure from insulin precursor to insulin reached up to 70%. In vivo assay showed that the biological activity of the produced recombinant human insulin was 28.8 U/mg.