About two-thirds of patients with transthyretin amyloid cardiomyopathy (ATTR-CM) were in advanced disease stages despite being diagnosed as recently as four months earlier, highlighting the need for earlier diagnosis, according to a study recently published in ESC Heart Failure.
The authors used data from patients with ATTR-CM treated in several hospitals in Germany between 2020 and 2021. The aim was to obtain a snapshot of demographic data, disease stage, comorbidities, outcomes and patient characteristics associated with tafamidis use.
What is ATTR-CM?
Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a rare progressive disease of the heart muscle that leads to congestive heart failure. It occurs when the transthyretin protein produced by the liver is unstable. Symptoms include fatigue; shortness of breath; irregular heart rate or palpitations; swelling of the legs, ankles and stomach; brain fog; wheezing; and dizziness. It often goes underdiagnosed because of a lack of awareness and knowledge of the disease. There is currently no cure for ATTR-CM.
The median age of the 300 patients analyzed in the study was 79, and more than 80% were men. Despite most patients having a relatively recent diagnosis (four months), most had advanced disease.
Read more about ATTR-CM testing and diagnosis
More than 63% of patients had a New York Heart Association (NYHA) score of III/IV and/or a National Amyloidosis Centre (NAC) stage of II. The NYHA score categorizes patients according to their grade of breathing difficulty; patients with scores III or IV experience difficulty breathing and performing mild tasks such as dressing and walking a few steps. The NAC staging system is based on cardiac biomarkers; patients with stage II have abnormal cardiac biomarkers in their blood.
“As indicated by NYHA class and NAC stage, these patients are still at an advanced stage of amyloidosis, underscoring the necessity of screening efforts for early detection,” the authors said.
Researchers evaluated how many of the patients included in the study would have been eligible for participating in the Transthyretin Amyloidosis Cardiomyopathy Clinical Trial (ATTR-ACT), which aimed to test the effectiveness and safety of tafamidis at 61 mg, the only disease-modifying therapy for ATTR-CM to date.
Most patients (64%) met the inclusion criteria for the trial; these patients tended to have more comorbidities, including diabetes, hypertension, coronary artery disease and lumbar spinal stenosis. Furthermore, they had worse echocardiographic and biomarker parameters.
Some 172 out of 197 patients from the group ended up receiving tafamidis at 61 mg. The most common reasons for not administering tafamidis were advanced heart failure and severely impaired general condition.
The patients who received tafamidis 61 mg were younger and had a better NYHA score. As expected, patients receiving tafamidis had a significantly better survival rate than those who did not.
“Acknowledging the very early phase of our study after approval of tafamidis 61 mg, there remains a need to validate clinical parameters for decision-making regarding treatment,” the authors said.