French researchers have developed a non-invasive ultrasound therapy for treating certain patients with aortic stenosis. In a small study published in The Lancet, they have proven its effectiveness. Emmanuel Messas, MD, PhD, a cardiologist and co-founder of the startup Cardiawave, which developed the device, explained the principle to Medscape Medical News.
Approximately 5 million patients in Europe and 5 million in the United States are affected by calcified aortic valve stenosis. „The aortic valve is a gateway between the heart and the body. As people age, it can become calcified, narrowing the valve opening. The typical area is 2-3 cm², but when it falls below 1 cm², there is significant constriction. In such cases, surgery is usually required due to the risk of heart failure or sudden death,“ Messas said.
For years, the standard treatment involved replacing the valve through open-heart surgery with extracorporeal circulation. A biological or mechanical valve was implanted in place of the defective valve.
In 2002, Alain Cribier, MD, a cardiologist at the University Hospital of Rouen in France, developed the Transcatheter Aortic Valve Replacement (TAVR), which allows valve replacement through interventional procedures that run through the arteries without opening the heart. This method reduces risks.
„But in both cases, the valve is replaced. However, 10-20% of patients have contraindications for these procedures. Our goal was to find an alternative for these individuals,“ Messas said.
To develop this solution, a spin-off of the European Georges-Pompidou Hospital and the Physics for Medicine Laboratory in Paris was founded: Non-invasive ultrasound therapy.
„We preserve the natural valve, but improve its opening function by sending ultrasound with a device attached to the chest. This is done with real-time guided ultrasound. The ultrasound creates a cavitation phenomenon that generates bubbles, which produce and cause oscillating shock waves, microfractures in the calcium of the valve. This makes it softer and easier to open,“ Messas explained.
„The technique is quite easy to perform. Simply place the device on the chest, position it well, and start the ultrasound. Seven sessions of 10 minutes each are required, which increases the procedure time, including setup time, to about 2 hours,“ he said. „The technique has two limitations: sometimes we do not see well enough with ultrasound, and sometimes the valve is too calcified and we cannot treat it.“
In a study published in The Lancet, 40 patients were treated with this technique in France, the Netherlands, and Serbia. „We had very ill patients with an average age of 83-84 years. They had an opening area of about 0.5 cm². These were compassionate patients for whom no other technique could be applied. We achieved an improvement in the opening area by 10%-15%: enough to improve symptoms,“ Messas said. Treated patients reported an improvement in their quality of life and a reduction in exertional dyspnea. After 6 months, the researchers observed an improvement in valve opening area by 0.1 cm². „We have altered the natural course of the disease, which normally decreases by 0.1 cm² per year,“ Messas said. Since the study was published, an additional 60 patients have been treated in France, the Netherlands, and Germany.
„The progress that this technology brings is that we preserve the patient’s natural valve and repair it in a non-invasive way,“ Messas said.
The next steps are to obtain the European Conformity (CE) marking and to start an early feasibility study in the United States. Indications could include not only patients with contraindications for surgery, but also patients with excessively calcified valves who could benefit from ultrasound treatment followed by TAVR. This new treatment could also be offered to young patients to delay interventional surgery as much as possible.
Messas estimated the potential beneficiaries to be about 1 million patients in Europe and 1 million in the United States.
(This article was translated from the French edition of Medscape.)