Wild-Type Transthyretin Amyloidosis in Female Patients - Consideration of Sex Differences

Gender Differences in the Evaluation and Management of New Acute CHF Due to ATTRwt Cardiac Amyloidosis

Cardiac amyloidosis can be grouped into two main categories: immunoglobulin light chain (AL) and transthyretin (hATTR or hereditary and ATTRwt or wild type). Cardiac infiltration of misfolded proteins can lead to significant infiltrative processes and subsequent heart failure. Diagnosis of ATTRwt heavily relies on clinical suspicion, as it typically appears later in life and is limited to the heart. It is routinely reported that ATTRwt significantly affects males more than females; however, older patients diagnosed with ATTRwt and those diagnosed at autopsy are significantly more likely to be female. Earlier, a more precise diagnosis in females could detect disease at an earlier stage and expedite treatment.

Iatrogenic intramuscular hematoma of the oblique muscles as a complication of technetium-99m-labeled pyrophosphate imaging-based computed tomography-guided core-needle biopsy in a patient with wild-type transthyretin cardiac amyloidosis

Technetium-99m-labeled pyrophosphate imaging-based computed tomography-guided core-needle biopsy of the internal oblique muscle with tracer uptake is a safe and sensitive extracardiac screening biopsy. It can provide histopathological confirmation of the deposition of amyloid transthyretin in patients with wild-type transthyretin cardiac amyloidosis. This case report presents the case of a 73-year-old man receiving triple anti-thrombotic therapy for atrial flutter and coronary stenting who underwent this biopsy to confirm the diagnosis of transthyretin cardiac amyloidosis. The biopsy needle reached the internal oblique muscle via the external oblique muscle between the skin and the target. A type 1 intramuscular hematoma involving these muscles developed subsequently; however, manual compression hemostasis prevented further increase in size. Since this biopsy often targets elderly patients receiving anti-thrombotic therapy who are at high risk of bleeding owing to multimorbidity and polypharmacy, efforts should be made to reduce the frequency of complications, particularly bleeding, which can lead to the development of intramuscular hematoma.

99mTc-Pyrophosphate Scintigraphy Can Image Tracer Uptake in Skeletal Trunk Muscles of Transthyretin Cardiac Amyloidosis

PURPOSE

99mTc-pyrophosphate (99mTc-PYP) uptake in the skeletal muscles is minimal in patients with transthyretin cardiac amyloidosis (ATTR-CA) when assessed qualitatively and quantitatively. We previously demonstrated moderate- to high-grade 99mTc-PYP uptake in the subcutaneous abdominal fat of some patients with ATTR-CA and showed that this abnormal finding could reflect the regional amyloid burden of this tissue. We aimed to investigate the frequency of 99mTc-PYP uptake in skeletal trunk muscles of patients with ATTR-CA.

METHODS

Chest- and abdomen-centered 99mTc-PYP scintigraphy images were obtained 2 hours after IV injections of the tracer (20 mCi) in 36 patients with ATTR-CA. The frequency of 99mTc-PYP uptake in the following 11 skeletal trunk muscles was investigated: pectoralis major, deltoid, subscapularis, infraspinatus, trapezius, latissimus dorsi, erector spinae, psoas major, abdominal oblique, rectus abdominis, and the gluteus muscles.

RESULTS

Ten of the 11 muscles were involved in patients with the highest number of 99mTc-PYP uptake in the skeletal trunk muscles examined, whereas no muscle was involved in a patient with the least uptake. The muscle with the highest rate of 99mTc-PYP uptake, observed in 34 of 36 patients (94.4%), was the abdominal oblique. No tracer uptake was observed in the psoas major. The frequency of radiotracer uptake in the remaining examined muscles was between those of abdominal oblique and psoas major muscles.

CONCLUSIONS

Radiotracer uptake was often detectable in some skeletal trunk muscles of ATTR-CA, although the muscles of patients examined and the skeletal trunk muscles of 1 patient showed heterogeneity in the uptake of 99mTc-PYP.

Sex differences among patients with transthyretin amyloid cardiomyopathy - from diagnosis to prognosis

AIMS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is predominantly diagnosed in men. The few available studies suggest affected women have a more favourable cardiac phenotype. We aimed to characterize sex differences among consecutive patients with non-hereditary and two prevalent forms of hereditary (h)ATTR-CM diagnosed over a 20-year period.

METHODS AND RESULTS

Analysis of deep phenotyping at presentation, changes on serial echocardiography and overall prognosis were evaluated. In total, 1732 consecutive patients were studied, comprising: 1095 with wild-type (wt)ATTR-CM; 206 with T60A-hATTR-CM; and 431 with V122I-hATTR-CM. Female prevalence was greater in T60A-hATTR-CM (29.6%) and V122I-hATTR-CM (27.8%) compared to wtATTR-CM (6%). At presentation, females were 3.3 years older than males (wtATTR-CM: 81.9 vs. 77.8 years; T60A-hATTR-CM: 68.7 vs. 65.1 years; V122I-hATTR-CM: 77.1 vs. 74.9 years). Body size significantly influenced measures of disease severity; when indexed, overall structural and functional phenotype was similar between sexes, the few significant differences suggested a mildly worse phenotype in females. No significant differences were observed in both disease progression on serial echocardiography and mortality across the overall population (p = 0.459) and when divided by genotype (wtATTR-CM: p = 0.730; T60A-hATTR-CM: p = 0.161; V122I-hATTR-CM: p = 0.056).

CONCLUSION

This study of a well-characterized large cohort of ATTR-CM patients did not demonstrate overall differences between sexes in either clinical phenotype, when indexed, or with respect to disease progression and prognosis. Non-indexed wall thickness measurements may have contributed to both under-representation and delays in diagnosis for affected females and highlights the potential role of utilizing indexed echocardiographic parameters for a more accurate assessment of patients at diagnosis and for disease prognostication.

Clinical recommendations to diagnose and monitor patients with transthyretin amyloid cardiomyopathy in Asia

Transthyretin amyloid cardiomyopathy (ATTR‐CM) is a debilitating and life‐threatening condition with a heterogeneous clinical presentation. Recent guidelines from the United States and Europe have been published to guide clinical practice and to facilitate management conformity by covering current diagnostic and treatment strategies for patients with ATTR‐CM. These guidelines highlight the importance of an early diagnosis to optimize therapeutic outcomes, specifying the use of tests and imaging techniques to allow accurate, noninvasive diagnosis of ATTR‐CM. However, as regional practice variations across Asia may limit access to healthcare, availability of specific tests, and expertise in assessing diagnostic images, there is an ongoing need to provide an Asian perspective on these clinical guidelines. This review article provides practical recommendations for the diagnosis and monitoring of patients with ATTR‐CM in Asia, highlighting the need for additional guidelines to support a broad and diverse population, consider differing healthcare systems and diagnostic testing availability, and provide a flexible yet robust algorithm.

Sex Differences in Wild-Type Transthyretin Amyloidosis: An Analysis from the Transthyretin Amyloidosis Outcomes Survey (THAOS)

Introduction

Wild-type transthyretin amyloidosis (ATTRwt amyloidosis) is a progressive disease resulting from the accumulation of wild-type transthyretin (TTR) amyloid fibrils, and is diagnosed primarily in males. This analysis examined sex differences in patients with ATTRwt amyloidosis from the Transthyretin Amyloidosis Outcomes Survey (THAOS).

Methods

THAOS is an ongoing, global, longitudinal, observational survey of patients with transthyretin amyloidosis, including both inherited and wild-type disease, and asymptomatic carriers of TTR mutations. THAOS data were analyzed to identify potential differences in demographic and clinical characteristics between males and females with ATTRwt amyloidosis (data cutoff: August 1, 2021).

Results

Of 1386 patients with ATTRwt amyloidosis, 84 (6%) were female and 1302 (94%) were male. Females had a higher median age at enrollment (80 vs. 78 years; p = 0.002) and symptom onset (75 vs. 73 years; p = 0.045) than males. Mean left ventricular (LV) ejection fraction was higher (53% vs. 48%; p = 0.001) and mean LV diastolic diameter lower (42 vs. 46 mm; p < 0.001) in females versus males, but sex was not identified as a predictor of LV mean wall thickness adjusted for height (beta coefficient − 0.22; p = 0.460) or a predominantly cardiac phenotype (odds ratio 1.60; p = 0.191). Modified polyneuropathy disability scores differed between groups (p < 0.001), with a larger proportion of scores ≥ IIIa among females (23% vs. 7%).

Conclusions

Females with ATTRwt amyloidosis in THAOS tended to present at a later age and showed signs of less severe cardiac impairment and more severe walking impairment.

Trial Registration

ClinicalTrials.gov: NCT00628745.

Sex-related differences in the clinical characteristics of wild-type transthyretin amyloidosis cardiomyopathy

BACKGROUND

A significant male predominance has been reported in wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM). Hence, female cases of ATTRwt-CM are overlooked, and sex-related differences in ATTRwt-CM remain unclear. This study aimed to examine sex-related differences in clinical characteristics and diagnostic approaches in ATTRwt-CM.

METHODS

We retrospectively analyzed 199 consecutive patients who were diagnosed with ATTRwt-CM and evaluated sex-related differences in clinical characteristics, imaging parameters, biomarkers, and diagnostic approaches.

RESULTS

Twenty-nine patients (15%) were female. These female patients were significantly older at diagnosis (77.1 ± 6.5 years vs. 82.9 ± 4.8 years; p<0.001) and had a more advanced New York Health Association functional class (2.2 ± 0.7 vs. 2.6 ± 0.8; p = 0.006) than their male counterparts. The median B-type natriuretic peptide levels were significantly higher (236 pg/mL vs. 394 pg/mL; p = 0.017) in female patients. Echocardiography revealed that the mean interventricular septum diameter was thinner (15.7 ± 2.6 mm vs. 14.1 ± 2.5 mm; p = 0.004) and left ventricular ejection fraction (LVEF) was preserved (51.2 ± 10.2% vs. 57.2 ± 9.1%; p = 0.003) in female patients. The mean heart-to-contralateral ratio obtained using ^99mTc-labeled pyrophosphate (^99mTc-PYP) was significantly lower (1.89 ± 0.33 vs. 1.63 ± 0.20; p < 0.001), moderate to severe aortic stenosis was more frequently observed (5% vs. 45%; p < 0.001), and the frequency of histological diagnosis was significantly lower (77% vs. 59%; p = 0.036) in female patients.

CONCLUSIONS

Female patients with ATTRwt-CM were predominantly octogenarians and less hypertrophic and had preserved LVEF and weaker cardiac uptake of the ^99mTc-PYP tracer compared with male patients. These characteristics contribute to the underdiagnosis of ATTRwt-CM in female patients.