Journal and News Scan

Researchers from the University of British Columbia, Seattle and Belgium successfully used a new approach that significantly minimized brain damage caused by ischemic stroke in mouse models. The new approach works by blocking hemichannels—pathways allowing for the flow of chemical ions and small molecules—that are expressed by astrocytes, ie, cells playing a protective role for neurons in the brain.

The hypothesis is that when stroke occurs, these hemichannels open and leak toxic molecules into the space outside the astrocytes, causing inflammation and damage to neurons; therefore, blockade of these channels may minimize damage to the brain during stroke.

In this study, a genetic approach that mutated the channel proteins, called Connexin-43 (Cx43), was used to block the formation of hemichannels. This allows the astrocytes to protect the neurons, significantly reducing the size of the stroke injury in the brain. Pharmacological blockade of Cx43 hemichannels with a molecule called TAT-Gap19 in the same ischemic stroke model, also resulted in smaller stroke damage.

These two approaches demonstrate that Connexin hemichannel blockers could be used as a neuroprotective agent in stroke. Thus, a new treatment of ischemic stroke may soon be possible. 

Connexin hemichannel blockers also have a potential role in treating other neurodegenerative conditions such as traumatic brain injury and Alzheimer's disease.

On Wednesday March 13, the ACC Quality Summit announced in New Orleans that beginning in mid-2019, hospitals performing transcatheter valve repair and replacement will be able to apply for the American College of Cardiology's new Transcatheter Valve Certification.

The ACC's Transcatheter Valve Certification is an external review and certification process that will hold hospitals to specific standards for multidisciplinary teams, formalized training and shared decision-making. Participation in a national clinical registries such as the Trancathether Valve Therapy (TVT) registry is required for certification. The TVT registry tracks patient characteristics, procedural indications, and outcomes for patients undergoing transcatheter aortic valve replacement and transcatheter mitral valve repair.

According to the release, the certification will link process improvements to patient outcomes and will be “responsive to the resourcing at hospitals focused and committed to performance improvement in patient care delivery and coordination post-procedure.” Participation in the program will also connect hospitals to data which can track performance metrics and inform best practices.

Siregar and colleagues review the methods for updating existing risk prediction models, an approach that allows models that have lost their predictive power to be adjusted to new clinical situations. When appropriate, this approach can be more efficient than creating an entirely new model. They consider five methods: intercept recalibration, logistic recalibration, model revision, closed test procedure, and Bayesian modeling. The authors then illustrate the application of these methods, using data from the Netherlands Heart Registry to update the EuroSCORE II model.

With the disruptive advancement of catheter-based technologies and minimally invasive techniques in structural heart disease, surgeons must obtain the necessary skills to continue to serve this large patient population. An emergency overhaul of current structural training must occur to ensure standardized training in structural heart disease. This is vital as surgeons are uniquely positioned to offer the full spectrum of valve therapy but risk erosion of the heart team concept without urgent action. The train has left the station and this manuscript is a call to action.