Use of attr cardiac amyloidosis imaging in latin america
Authors: Alexanderson-Rosas E , Carvajal-Juarez I , Erriest J , Blacher-Grossman G , Camilletti J , Mut F 
Published: June 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background/Introduction
Transthyretin amyloid cardiomyopathy (ATTR-CM) is associated with high morbidity and mortality(1). Non-invasive imaging techniques and novel treatments allow for a better prognosis, but a lack of clinical awareness of the proper use of imaging delays appropriate diagnosis and management. Since 2019, when the multi-society expert consensus on recommendations for multimodality imaging in cardiac amyloidosis (2) was published, multiple international societies have also published their position (3) making imaging techniques such as nuclear medicine scintigraphy (NMS), cardiac magnetic resonance (CMR) and transthoracic echocardiogram (TTE) the methods of choice for the diagnosis of ATTR-CM.

Purpose
We aim to know how non-invasive imaging methods are used to diagnose ATTR-CM in Latin America (LA)

Methods
Anonymous online surveys were distributed digitally among clinicians across LA for two months (June-July 2021). We asked about the availability and use of non-invasive cardiac imaging techniques to diagnose ATTR-CA. The information was automatically entered into a spreadsheet for tabulation and descriptive statistical analysis (Microsoft Excel 2016).

Results
Surveys were collected from 82 NM centers and 406 clinicians (mainly cardiologists, 65%), with responses from professionals from 17 of the 20 LA countries. The diagnostic image most available among the respondents was NMS (100%), followed by TTE ( 86%), and the last, CMR (76%). Fig 1. All nuclear medicine centers have access to perform SPECT acquisition, but advanced technology is lacking in some areas (SPECT/CT-44%, CZT-7%). Of the available phosphonates, PYP is accessible in most centers (83%); a minority use HMPD (12%), and just four centers use MDP (5%). Regarding TTE availability, only 59% can perform advanced techniques as GLS. Something similar happens in the availability of CMR since only 42% have access to advances sequences as mapping. When we presented a clinical scenario of a patient with a suspicious ETT of ATTR-CM, the following main study to request was CMR (43%), and only 38% considered NMS as the next one. 65% of the clinician's responders had not ordered a single NMS during the year before the survey. Of the remaining 35% who had requested the procedure, 27% had ordered 1–5 studies, and only 4% more than 10. The five countries where more NMS are acquired are Brazil, Argentina, Chile, Colombia, and Mexico. Fig 2.

Conclusion(s)
We present a representative sample of what happens in LA regarding the use of non-invasive imaging to diagnose ATTR-CM. Essential diagnostic imaging resources are reasonably available in the region but are under-utilized, probably because of the limited awareness of clinicians. Advance technology such as SPECT/CT, CZT, strain, and mapping are lacking; investment in technological infrastructure is needed. The survey demonstrated the need for educational programs to increase the utilization of diagnostic imaging in ATTR-CM.