Contemplative cafés and small shops frame the backyard in the middle of Berlin-Schoeneberg. At first glance, you would not expect medical high-tech to be found in this rather inconspicuous place. And yet it is the scene of a remarkable development in cardiac medicine, because Abiomed is based here.

The American medical technology company operates two locations in Germany under the Abiomed Europe branch. The head office is in Aachen, where 400 employees primarily produce. With 16 employees and spacious laboratories, Berlin is an important development location for the company, which specializes in the development and manufacture of miniature cardiac assist systems. The target group includes heart attack patients whose heart muscle needs temporary support.

Impella ECP continues an existing pump series. Clinical trials involving several hundred patients are scheduled to begin in the coming months. The Impella ECP was developed by a team of doctors, engineers and scientists in the company’s Berlin laboratories. Abiomed publicly advertises the device as the “smallest heart pump in the world”. This cannot be reliably verified.

In fact, however, the pump is tiny. At ten centimeters long, its diameter is just three millimeters. And yet it should be strong enough to replace a large part of the heart’s natural pumping power – at least around five liters per minute – for a certain period of time. Its power center is a tiny propeller integrated into the housing, a so-called impeller. The product name is also derived from it.

From the point of view of Abiomed Europe Managing Director and Impella developer Thorsten Siess, the pump is “a technological breakthrough”. The demonstration of the device at least gives an idea of ​​why. While other heart pumps are usually attached to the heart externally or operate entirely outside the body, the Impella is placed directly in the heart.

Siess demonstrates this on a model. First, he inserts the pump, which sits at the tip of a long guidewire, into a thin, flexible, five-foot-long tube. This tube is also called a catheter. He pushes the hose and pump together via the large inguinal artery into the body and, with feeling, further and further through the vessels to just in front of the heart. There he releases the pump from the surrounding catheter and guides it through the aorta and atrium into the left ventricle.

A squiggle at the tip called a pigtail prevents injuries. The device, three millimeters thick, suddenly becomes a heart pump with twice the diameter when it is detached from the catheter. In the left ventricle, the small propeller sucks in the blood at a speed of up to 50,000 per minute in order to eject it back into the main artery – the aorta – at the other end. From there it is transported to the various regions of the body.

The Impella ECP is the first expandable heart pump in the series. A motor the size of a remote control at the other end of the wire outside the body drives them. There is a long development process behind it. “It took 22 years from the idea to the first trial on patients in 2021,” says Sieß.

The challenge was primarily to get as much performance as possible in the smallest possible device. Because the larger the diameter of a catheter-supported pump, the more likely it is that something can go wrong when it is inserted and left in the body, explains Alexander Ghanem, spokesman for the interventional cardiology working group of the German Society for Cardiology and chief physician at Hamburg’s Asklepios Klinik Nord.

This is especially true when less experienced cardiologists are at work. “The price of these pumps is poor circulation in the leg where they are inserted into the body and bleeding at the puncture site,” says Ghanem. The development of ever smaller pumps is therefore definitely beneficial. “Especially in smaller clinics, every millimeter is a huge issue. If you want to get the pumps into the general supply, three millimeters is already significantly better than four millimeters.”

Problem with the matter: “The diameter of a pump correlates strongly with the blood flow that it can create,” explains Siess. “Unless you make it expandable.” While other three-millimeter pumps in the series can handle a maximum delivery volume of two liters of blood per minute, the Impella ECP can manage up to four and a half liters when expanded. “This enables us to provide significant heart support, so that we can already cover the majority of indications with the pump.”

Patients who have suffered cardiogenic shock as a result of a heart attack, for example, and whose heart is no longer able to pump enough blood into the circulatory system, should primarily benefit from the pump system. It is then urgently dependent on temporary support. None of the previously available Impella pumps are intended for long-term use as an artificial heart. As a rule, the pumps are removed again after a few days at the latest. After all, the aim is always to restore at least part of the heart function, according to Siess.

So far, patients have received support after cardiogenic shock, mostly in the form of medication, such as the stress hormone adrenaline. This increases heart activity. But the drugs are not without controversy, they not only increase activity, but also oxygen consumption of the heart.

Cardiologist Ghanem explains their effect: “You have to imagine the heart after such a cardiogenic shock as a horse that pulls a wagon that is too heavy. With the drugs, this horse is whipped, so to speak. That works fine sometimes, but at some point the horse collapses.” The drugs are therefore not a sustainable solution. The alternative, large heart-lung machines that are outside the body and take over the gas exchange and pumping function from there, are comparatively difficult to use.

The mini heart pumps are therefore actually a good therapy option, says Ghanem. According to Abiomed, they have already been used in over 200,000 patients worldwide. Despite the weak scientific evidence to date, the currently applicable guideline of the European Society of Cardiology also recommends its use in cardiogenic shock, says Ghanem. “These catheter-based pumps are, to stay with the metaphor, a tractor that takes the strain off the horse at work for a while. Once the horse has recovered, the tractor can be unhitched and removed.”