Usefulness of relative apical longitudinal strain index to predict positive ^99mTc‐labeled pyrophosphate scintigraphy findings in advanced‐age patients with suspected transthyretin amyloid cardiomyopathy

Abstract

Background We previously reported that a high score (2 or 3 points) according to the Kumamoto criteria, a combination of high‐sensitivity cardiac troponin T (hs‐cTnT) ≥0.308 ng/mL, the length of QRS ≥ 120 ms in electrocardiogram, and left ventricular (LV) posterior wall thickness ≥ 13.6 mm, increases the pretest probability of 99mTc‐labeled pyrophosphate (99mTc‐PYP) scintigraphy in patients with suspected transthyretin amyloid cardiomyopathy (ATTR‐CM). However, some patients with a low score (0 or 1 point) show positive findings on 99mTc‐PYP scintigraphy. Therefore, we evaluated the usefulness of additional examinations, including echocardiographic assessment of myocardial strain, to raise the pretest probability of 99mTc‐PYP scintigraphy for these patients. Methods and Results We examined 109 consecutive patients aged ≥70 years with low scores according to the Kumamoto criteria who underwent 99mTc‐PYP scintigraphy. Nineteen patients (17%) had positive 99mTc‐PYP scintigraphy findings. The relative apical longitudinal strain (LS) index (apical LS/ basal LS + mid LS) (RapLSI) was significantly higher in patients with positive than negative 99mTc‐PYP scintigraphy findings (1.04 ± 0.37 vs 0.70 ± 0.28, P < .01). Multivariable logistic regression analysis revealed that a high RapLSI (≥1.04) was significantly associated with 99mTc‐PYP positivity (odds ratio, 14.14; 95% confidence interval, 3.36‐59.47; P < .01). The sensitivity, specificity, and accuracy of the diagnostic model using the RapLSI for identification of 99mTc‐PYP positivity were 53%, 94%, and 87%, respectively. Conclusions A high RapLSI can raise the pretest probability of 99mTc‐PYP scintigraphy in patients with a low score according to the Kumamoto criteria. The RapLSI can assist clinicians in determining strategies for these patients.

Comparison of left ventricular global and segmental strain parameters by cardiovascular magnetic resonance tissue tracking in light-chain cardiac amyloidosis and hypertrophic cardiomyopathy

“…The RAB is simple to calculate and mainly involves the evaluation of the difference between the basal and apical strains (37). By contrast, the middle segmental strain can be included in the RAS calculation to make the evaluation more comprehensive and reasonable (38). In contrast to similar studies (34,37), we added the evaluation of the RAB and the RAS of the radial and circumferential strain parameters.…”

Prognostic value of left atrial strain in patients with wild‐type transthyretin amyloid cardiomyopathy

“…In these days, however, non‐biopsy diagnosis of ATTR‐CM by using bone scintigraphy including 99m Tc‐labelled pyrophosphate scintigraphy ( 99m Tc‐PYP) has been established 9 . Therefore, modified Kumamoto Criteria are used to raise the pretest probability of ATTR‐CM by using inexpensive tests such as laboratory examinations, electrocardiography, and transthoracic echocardiography, followed by 99m Tc‐PYP is performed for probable diagnosis of ATTRwt‐CM in Kumamoto University Hospital (Supporting Information, Figure ) 10 . For many patients with 99m Tc‐PYP positivity, tissue biopsy is performed for definite diagnosis of ATTRwt‐CM.…”

Echocardiographic diagnosis of cardiac amyloidosis: Does the masquerader require only a "cherry on top"?

“…In the study published in this journal, 3 the authors (also from the Kumamoto University, Japan) wanted to explore whether additional examinations, including echocardiographic assessment of myocardial strain using two‐dimensional speckle‐tracking echocardiography, could increase the pretest probability of 99mTc‐PYP scintigraphy for these patients, particularly in subjects with low scores (zero to one) on the basis of the Kumamoto criteria 5 . They quantified left ventricular segmental strain in the basal, mid‐, and apical regions in order to calculate an index which represents a ratio of the apical versus a combination of basal and mid‐ventricular strain, using the classic Bull's eye pattern of strain distribution (the so‐called "cherry‐shaped" apical strain pattern), along the entire 17 left ventricular segments.…”

“…Cardiac amyloidosis may even coexist with aortic stenosis 1 and other patients with new‐onset atrial fibrillation 2 . In this editorial, we discuss the role of left ventricular speckle‐tracking echocardiography in the assessment of cardiac amyloidosis (CA) in reference to the original work published in this issue of the journal 3 …”

“…The basis of the study 3 the editorial is focusing on is the data previously obtained from a group of 181 consecutive patients with the mixed disease and clinical suspicion of CA aged ≥ 70 years, who underwent 99 mTc‐PYP scintigraphy at the Kumamoto University Hospital, Kumamoto, Japan, between January 2012 and December 2018 5 . A logistic regression analysis of all clinical and echocardiographic parameters revealed that high‐sensitivity cardiac troponin T (hs‐cTnT) ≥ 0.0308 ng/mL, left ventricular posterior wall thickness ≥ 13.6 mm, and a wide QRS complex (QRS ≥ 120 ms) were strongly associated with 99 mTc‐PYP positivity.…”