A new device developed by two heart device manufacturers — called the interatrial shunt — is currently being tested in clinical trials at several sites nationwide, including at U.Va. Health. If the results of the trial prove promising, these devices could help ease symptoms in heart failure patients and increase their quality of life.
The device was independently developed by Corvia Medical, Inc. and V-Wave Medical — the University joined the Corvia trial in 2017 and the V-Wave trial in 2020, according to Allison Raymond, a clinical research coordinator at U.Va. Health. Raymond said that in total, the Corvia trial has 118 sites and V-Wave has 102 in the U.S. and around the world.
Dr. Nishitha Sodhi, structural and interventional cardiologist at U.Va. Health, spoke on the novelty of the interatrial shunt and how U.Va Health is fortunate to be able to participate in the clinical trials for the device.
“We are fortunate that we have minimally invasive procedural options here at U.Va.,” Sodhi said. “Some of these are already FDA-approved and sort of available elsewhere, but the unique ones are the clinical trial procedures that we offer here that are offered only at very select sites across the country and the world.”
The interatrial shunt is one such device.
“I would say that there are no other devices like [the interatrial shunt] currently for heart failure,” Sodhi said.
Heart failure is a condition where the heart cannot pump blood properly because it has become weak. The heart muscles can become weak due to a variety of different causes, but some of the most common include coronary heart disease and high blood pressure. As a result of this weakening, blood flows backwards and builds up in the left side of the heart, causing increased pressure in the heart and lungs and swelling in other parts of the body.
Dr. Sula Mazimba, cardiologist at U.Va. Health and principal investigator (PI) of the ongoing clinical trials, explained that one sub-type of heart failure is the “stiff” heart, where the heart is able to pump blood well but not relax, leading to increased pressure in the heart.
The interatrial shunt is designed to allow pressure to be relieved from the left side of the heart. A hole is made in the heart and the shunt is placed in this hole to allow blood to flow from the left side to the right side. This helps to reduce the pressure and buildup of fluid in the heart and body.
“There's tissue between the two chambers of the heart, called the septum, and this [device] basically sits in between those two chambers through that septum in the top two chambers of the heart, ” Sodhi said.
The device is inserted into the patient via a minimally invasive procedure and could defer the need for advanced options such as mechanical pumps or heart transplants for some patients, according to Sodhi. According to one paper, approximately 125,000 to 250,000 heart failure patients in the U.S. could be candidates for these advanced treatment options. In addition, early data from trials show that the device helps ease congestive symptoms in patients.
“When there's less congestion in the left side of the heart, then what we're seeing is that patients feel better, they're not as short of breath and they have less heart failure exacerbations,” Sodhi said.
The clinical trials being conducted will show whether the device’s benefits hold for large numbers of patients.
“[In a small selection of patients], we've shown that the device does improve numbers — hemodynamics and distance walked and all those parameters — and that's why we're doing a clinical trial to sort of see whether that holds in a larger patient population,” Mazimba said.
Using a device like the interatrial shunt embodies a new approach for mitigating heart failure. According to Sodhi, medicines such as beta blockers and ACE inhibitors are the main treatment prescribed to patients. However, these medicines prove insufficient for some patients who have advanced heart failure and are deemed refractory, or unresponsive, to medical therapies. These patients could potentially benefit from the interatrial shunt.
“Some of these clinical trial devices, the nice thing about them is that they could potentially be utilized on patients that have been refractory to medical therapy, but are not ready and so advanced yet for a heart transplant,” Sodhi said. “So we have some options in the interim until they get to the point of needing [a] transplant or a mechanical pump.”
According to Mazimba, the concept of making a hole in tissue to relieve pressure has been used for another condition called pulmonary hypertension, in which there is high pressure in the lungs and right side of the heart. However, it is unlike the interatrial shunt because there is no mechanism to leave the hole open.
“It was sort of a crude way of just poking a hole, which almost always closes down the road,” Mazimba said.
Heart pressure during exercise helped motivate the design of the Corvia shunt.
“Basically, if you have heart failure — specifically I talk about diastolic heart failure here — and go out walking at a brisk pace, your left sided pressures increase, which can cause symptoms such as shortness of breath, chest pain or fatigue,” Raymond said in an email to The Cavalier Daily. “When the pressures increase, it helps facilitate the shunt as naturally things move from high pressure to low pressure.”
Both Sodhi and Mazimba discussed the need to be prudent when selecting patients to receive the device. According to Sodhi, cardiologists use a variety of criteria, such as hemodynamics, to assess the pressure in various chambers of the patient’s heart and determine whether patients would benefit from the interatrial shunt. Mazimba noted that the trials also outline specific inclusion and exclusion criteria to follow when selecting patient and that doctors need to carefully select patients to receive the device
“There are some patients who you worry that if you put a shunt, you might overwhelm one side of the heart more than the other and that will cause more problems,” Mazimba said.
According to Sodhi, the risks associated with the device are low and are likely attributable to the insertion process rather than the shunt itself, making the device a relatively safe alternative for heart failure patients.
“Any procedure comes with risks, including bleeding, infection, injury to the heart and lungs,” Sodhi said. “But there's nothing that we so far are seeing that would prevent us from trying to use this.”
Mazimba also expressed the device’s safety.
“That's precisely the reason why the clinical trial is ongoing — because it's very safe and is promising,” Mazimba said.