Early Outcomes With the Evolut PRO Repositionable Self-Expanding Transcatheter Aortic Valve With Pericardial Wrap.

OBJECTIVES: This study sought to evaluate the Medtronic Evolut PRO Transcatheter Aortic Valve System in patients with severe symptomatic aortic stenosis. BACKGROUND: A next-generation self-expanding transcatheter aortic valve was designed with an external pericardial wrap with the intent to reduce paravalvular leak while maintaining the benefits of a low-profile, self-expanding, and repositionable supra-annular valve. METHODS: The Medtronic Evolut PRO Clinical Study included 60 patients undergoing transcatheter aortic valve replacement with the Evolut PRO valve at 8 investigational sites in the United States. Clinical outcomes at 30 days were evaluated using Valve Academic Research Consortium-2 criteria. The 2 primary safety endpoints were the incidence of all-cause mortality at 30 days and the incidence of disabling stroke at 30 days. The primary efficacy endpoint was the proportion of patients with no or trace prosthetic valve regurgitation at 30 days. An independent echocardiographic core laboratory (Mayo Clinic, Rochester, Minnesota) was used to adjudicate all echocardiographic assessments. RESULTS: All 60 patients received the Evolut PRO valve. At 30 days, 1 patient (1.7%) died and 1 patient (1.7%) experienced a nonfatal disabling stroke. Paravalvular regurgitation at 30 days was absent or trace in 72.4% of patients and was mild in the remainder of patients, with no patients having worse than mild paravavlular leak. The mean atrioventricular gradient was 6.4 ± 2.1 mm Hg and effective orifice area was 2.0 ± 0.5 cm2 at 30 days. CONCLUSIONS: The safety and efficacy results of this study support the use of the Evolut PRO System for the treatment of severe symptomatic aortic stenosis in patients who are at increased surgical risk, resulting in excellent hemodynamics and minimal paravalvular leak (The Medtronic TAVR 2.0 US Clinical Study; NCT02738853).

Math5 expression and function in the central auditory system.

The basic helix-loop-helix (bHLH) transcription factor Math5 (Atoh7) is required for retinal ganglion cell (RGC) and optic nerve development. Using Math5-lacZ knockout mice, we have identified an additional expression domain for Math5 outside the eye, in functionally connected structures of the central auditory system. In the adult hindbrain, the cytoplasmic Math5-lacZ reporter is expressed within the ventral cochlear nucleus (VCN), in a subpopulation of neurons that project to medial nucleus of the trapezoid body (MNTB), lateral superior olive (LSO), and lateral lemniscus (LL). These cells were identified as globular and small spherical bushy cells based on their morphology, abundance, distribution within the cochlear nucleus (CN), co-expression of Kv1.1, Kv3.1b and Kcnq4 potassium channels, and projection patterns within the auditory brainstem. Math5-lacZ is also expressed by cochlear root neurons in the auditory nerve. During embryonic development, Math5-lacZ was detected in precursor cells emerging from the caudal rhombic lip from embryonic day (E)12 onwards, consistent with the time course of CN neurogenesis. These cells co-express MafB and are post-mitotic. Math5 expression in the CN was verified by mRNA in situ hybridization, and the identity of positive neurons was confirmed morphologically using a Math5-Cre BAC transgene with an alkaline phosphatase reporter. The hindbrains of Math5 mutants appear grossly normal, with the exception of the CN. Although overall CN dimensions are unchanged, the lacZ-positive cells are significantly smaller in Math5 -/- mice compared to Math5 +/- mice, suggesting these neurons may function abnormally. The auditory brainstem response (ABR) of Math5 mutants was evaluated in a BALB/cJ congenic background. ABR thresholds of Math5 -/- mice were similar to those of wild-type and heterozygous mice, but the interpeak latencies for Peaks II-IV were significantly altered. These temporal changes are consistent with a higher-level auditory processing disorder involving the CN, potentially affecting the integration of binaural sensory information.

Conserved regulation of Math5 and Math1 revealed by Math5-GFP transgenes.

Retinal ganglion cell genesis requires the proneural bHLH transcription factor Math5 (Atoh7), but little is known about the regulatory elements that control its expression. Here, we investigate Math5 gene regulation using transgenic mice. These mice express GFP in the prenatal retina, live-labeling RGC axon migration and innervation of the brain. Unexpectedly, these Math5-GFP transgenes are also found in Math1 expression domains throughout the nervous system, intriguing since Math5 and Math1 normally exhibit nonoverlapping expression. Furthermore, Math5-GFP and Math1 are regulated similarly, by both Pax6 and Math1 itself, in the lower rhombic lip and dorsal spinal cord. We also show that Pax6 binds to particular Math5 and Math1 regulatory sequences in vitro. Together these data suggest that these atonal semi-orthologues may share conserved regulatory elements that are normally silent in the Math5 gene.