Labour MP Ann Clwyd has called for the chair and chief executive of Cardiff and the Vale Health Board to resign, claiming details of the investigation into her husband's death were released "for spiteful and political reasons".
A review into the NHS complaints system has concluded that there must be a "revolution".
The report, led by Labour MP Ann Clwyd, found that people think there is a "lack of independence" in the current system, with the way many hospitals handle complaints akin to "marking their own homework".
Patients and their families are reluctant to complain about bad care and hospitals are too "defensive" to hear and address concerns, the review found.
The report concluded that it should not be "painful or difficult" to complain about poor care. It made a string of recommendations from patients' bedsides to hospital board room.
The law firm that represented a woman who spent eight years fighting for the NHS to explain why her father died following poor care at a Worcestershire hospital has welcomed the upcoming review into the complaints system.
Leigh Day said that the report is "well overdue", adding that some of its clients have spent up to six years trying to get a response to their complaints.
Nearly three-quarters of those who we represented at Stafford Hospital felt that the NHS complaints system was tortuous and did not respect the emotional distress caused by having to relive the trauma through making a complaint.
Instead, all too often, the response they received was bureaucratic or they received no response at all.
A woman who had to wait eight years for an NHS explanation of why her father died as he received poor care at a Worcestershire hospital has said the NHS complaints system must "fundamentally change".
Pauline Robles' 85-year-old father died nine days after being admitted to Alexandra Hospital in Redditch, after the hospital failed to administer any of the heart medication he had been taking for more than 20 years.
Following an eight-year battle to get the answers she and her family needed, they finally received a letter of apology in January this year, after involving solicitors.