Prevalence of cardiac amyloidosis among cardiac- and non-cardiac patients undergoing echocardiography at a large university echo lab in Germany: a cohort study
Authors: Otto S , Albrecht R , Hamadanchi A , Franz M , Westphal J G , Schulze P C 
Published: October 2022

Abstract

Background
Cardiac amyloidosis (CA) is a progressive infiltrative cardiomyopathy that leads to severe heart failure and, once clinically relevant, poses a high mortality risk. Epidemiological data for CA are still sparse and heterogeneous, but urgently needed since novel therapies against ATTR-CA are now available.

Aim
We aimed to assess minimum prevalence rates of CA among cardiac and non-cardiac patients undergoing routine echocardiography in an echo lab of a large university clinic serving all medical specialities in central Germany.

Methods
We established a retro- and prospective database based on suspicious findings in echocardiography for all echocardiographic exams over an 8.5 year period (03/2013 and 09/2021). During this time, 41,375 patients underwent at least one echo exam. Indication for echos were mixed, and consisted of non-cardiac and cardiac patients with acute and chronic illnesses as well as screening exams (e.g. before major surgery or chemotherapy). Suspicious echocardiography were retrospectively analysed whether they underwent further diagnostic or if it remained an unproven suspicion (figure). All echos of suspicious cases were comprehensively re-analysed regarding novel surrogate parameters and indices for CA. Various clinical and laboratory parameters were collected.

Results
The mean age of the cohort of 41,375 patients was 65.1±15.8 years for the first or only echo examination with a slightly unbalanced gender distribution (45% female). The age distribution is shown in the table. While 128 patients were suspected, the diagnosis was falsified in 16 patients and proven in 47 patients (light chain n=16, ATTR n=31; figure). A substantial proportion of patients with suspicious echo received no further diagnostic work-up (N=65). Over the given time frame of 101 months, the prevalence of suspicious echocardiograms was 1 per 323 patients (or 31 per 10,000). The proven cases had a prevalence of 1 per 880 patients (or 11.3 per 10,000). Since ATTR-CA is a disease of the elderly, we saw a vanishingly small number of cases in persons younger than 70 years (table), whereas 90% of all CA patients were older than 70 years. At timing of diagnosis, AL-CA patients were almost 10 years younger compared to diagnosis of ATTR-CA (69.1±8.4 years vs. 77.4±8.5 years). In patients older than 80 years, the prevalence rate of ATTR-CA peaked with 22.6 cases per 10.000 patients (0.23%). The prevalence rate of ATTR-CA was roughly twice as high compared to AL-CA.

Conclusion
For the first time, an estimation of minimum prevalence rates for CA for a defined volume of echocardiograms in an all-comers population is provided. In a mixed population of a hospital of maximum care CA prevalence rate is much higher than expected. Awareness for this “rare” disease is needed, since routine echo exams can prompt suspicion in clinically silent or so far unrecognized CA cases.

Funding Acknowledgement
Type of funding sources: None.