A congressional oversight subcommittee is seeking an investigation into the Food and Drug Administration's oversight of HeartWare, a device produced by Medtronic.

The company took HeartWare off the market in June 2021 as growing clinical evidence showed a higher rate of stroke and death among patients using the product when compared to similar devices.

An investigative series published last year by ProPublica raised questions about the federal agency's response to complaints about HeartWare.

Last week, U.S. Rep. Raja Krishnamoorthi, D-Ill., sent a letter to the FDA requesting more information about the agency's handling of HeartWare's potential problems: "I am concerned by FDA's slow action, over multiple administrations, to protect patients from this product despite early warning signs," he wrote.

Krishnamoorthi is chairman of the U.S. House Committee on Oversight and Reform's Subcommittee on Economic and Consumer Policy. A Medtronic representative declined to comment on the subcommittee's investigation.

The HeartWare Ventricular Assist Device (HVAD) was created to help patients with severe heart failure. The HVAD was a mechanical pump designed to increase blood flow through the body.

Medtronic acquired Massachusetts-based HeartWare International in 2016 for $1.1 billion. Problems with the device predated Medtronic's ownership. The FDA issued its first warning letter about the product in 2014.

"Between 2014 and 2021, the device underwent 15 company-initiated Class I recalls, first for assorted parts, including the external controller and battery cell, and finally for the entire defective system," Krishnamoorthi wrote in the letter.

In mid-April 2021 Medtronic recalled HeartWare cables for its battery, data and adapters. At that time, the FDA said it had received reports of 12 deaths and eight injuries associated with HeartWare. The entire device was recalled weeks later.