NEW YORK — The US Food and Drug Administration (FDA) has issued its highest-level alert about a heart pump that has been linked to 49 deaths and 129 injuries.

The Impella left sided pumps are used to temporarily support a patient's heart during high-risk procedures or after a severe heart attack.

But the regulator warned it could puncture a wall in the heart's left ventricle if used incorrectly.

The device's manufacturer, Abiomed, has issued new instructions for the pump.

A summary posted on the FDA's website on March 21 classified the move as "most serious type of recall" because of the risk of serious injuries or death if the device is used incorrectly.

The agency warned that the use of affected pumps may also cause serious adverse health consequences, including "hypertension, lack of blood flow, and death".

But it added that the recall was a correction, not a product removal, and the device will remain on the market.

The notice relates to 66,390 devices that were distributed in the US over two years starting from Oct. 10, 2021, the agency said.

The device was given FDA approval in 2008.

The pump has a catheter with a small hook at the end, which is threaded through the blood vessels and in to the left ventricle — a key chamber in the heart used to pump blood full of oxygen around the body.

A spokesperson for Johnson & Johnson — which acquired Abiomed in 2022 — told Reuters: "This notification is not a device removal and Impella heart pumps remain on the market and available for patients."

Abiomed first disclosed the risk of heart perforation during insertion of the pumps in a technical bulletin posted in October 2021, but did not share this information with the FDA at the time, the agency said.

The agency carried out an inspection of the firm's office in Massachusetts in early 2023, and sent a warning letter to Abiomed in September where it criticized — among other things — a failure to update the FDA on the risk of heart perforation.

The warning letter resulted in the Abiomed issuing a "Urgent Medical Device Correction letter" late last year, containing revised instructions for using the heart pump correctly, including how to position the pump's catheter or use imaging when turning it during procedures, the FDA said. — BBC