Recent advances in the noninvasive strategies of cardiac amyloidosis

Suspicion, screening, and diagnosis of wild-type transthyretin amyloid cardiomyopathy: a systematic literature review

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt CM) is a more common disease than previously thought. Awareness of ATTRwt CM and its diagnosis has been challenged by its unspecific and widely distributed clinical manifestations and traditionally invasive diagnostic tools. Recent advances in echocardiography and cardiac magnetic resonance (CMR), non-invasive diagnosis by bone scintigraphy, and the development of disease-modifying treatments have resulted in an increased interest, reflected in multiple publications especially during the last decade. To get an overview of the scientific knowledge and gaps related to patient entry, suspicion, diagnosis, and systematic screening of ATTRwt CM, we developed a framework to systematically map the available evidence of (i) when to suspect ATTRwt CM in a patient, (ii) how to diagnose the disease, and (iii) which at-risk populations to screen for ATTRwt CM. Articles published between 2010 and August 2021 containing part of or a full diagnostic pathway for ATTRwt CM were included. From these articles, data for patient entry, suspicion, diagnosis, and screening were extracted, as were key study design and results from the original studies referred to. A total of 50 articles met the inclusion criteria. Of these, five were position statements from academic societies, while one was a clinical guideline. Three articles discussed the importance of primary care providers in terms of patient entry, while the remaining articles had the cardiovascular setting as point of departure. The most frequently mentioned suspicion criteria were ventricular wall thickening (44/50), carpal tunnel syndrome (42/50), and late gadolinium enhancement on CMR (43/50). Diagnostic pathways varied slightly, but most included bone scintigraphy, exclusion of light-chain amyloidosis, and the possibility of doing a biopsy. Systematic screening was mentioned in 16 articles, 10 of which suggested specific at-risk populations for screening. The European Society of Cardiology recommends to screen patients with a wall thickness ≥12 mm and heart failure, aortic stenosis, or red flag symptoms, especially if they are >65 years. The underlying evidence was generally good for diagnosis, while significant gaps were identified for the relevance and mutual ranking of the different suspicion criteria and for systematic screening. Conclusively, patient entry was neglected in the reviewed literature. While multiple red flags were described, high-quality prospective studies designed to evaluate their suitability as suspicion criteria were lacking. An upcoming task lies in defining and evaluating at-risk populations for screening. All are steps needed to promote early detection and diagnosis of ATTRwt CM, a prerequisite for timely treatment.

[Value of (11)C-PiB PET/MRI in the evaluation of organ involvement in primary systemic light chain amyloidosis]

Objective: To analyze the value of (11)C-PiB PET/MRI for evaluating organ involvement in patients with primary light chain amyloidosis (pAL) . Methods: The clinical data of 20 patients with pAL and 3 healthy volunteers from January 2019 to October 2021 were retrospectively analyzed. The correlation between the organ involvement evaluated by clinical standards and PET/MRI was compared. The relationship between cardiac-related biological indicators, disease stage, and the maximum standardized uptake value (SUVmax) were analyzed. The relationship between 24-hour urinary protein quantification and kidney SUVmax was analyzed. Results: ①In 20 patients (18 newly diagnosed patients and 2 non-newly diagnosed patients) ,(11)C-PiB positive uptake was observed in the heart (15 patients, 75%) , lung (8 patients, 40%) , bone marrow (10 patients, 50%) , muscle (10 patients, 50%) , tongue muscle (7 patients, 35%) , thyroid (6 patients, 30%) , salivary gland (4 patients, 20%) , spleen (2 patients, 10%) , and stomach wall (1 patient, 5%) . ②Organ involvement on (11)C-PiB PET/MRI showed good correlations with the clinical evaluation criteria for the heart and bone marrow. The positive rate of PET/MRI evaluation in the lung, spleen, gland, muscle, and tongue muscle was significantly higher than the clinical criteria. However, (11)C-PiB PET/MRI has limitations in the evaluation of the nervous system and fat tissue. ③To analyze the relationship between cardiac-related biological indexes and the SUVmax of the heart in 13 newly diagnosed patients. Patients with left ventricular ejection fraction (LVEF) <50% and interventricular septal thickness (ISV) ≥1.2 cm showed a higher SUVmax than patients with LVEF ≥50% and ISV<1.2 cm (P<0.05) .There are significant differences in the SUVmax of the heart between the Mayo2004 stage and the Mayo2012 stage. The later the disease stage, the higher the SUVmax (P<0.05) . The SUVmax of the heart was positively correlated with cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) (P<0.01) .There was no significant correlation between renal SUVmax and 24-hour urine protein (P>0.05) . Conclusion: Whole body (11)C-PiB PET/MRI, as a visualization system of amyloid protein, is used to qualitatively evaluate organ involvement, which can improve the level of early non-invasive diagnosis. Whole body (11)C-PiB PET/MRI can be used to perform quantitative evaluation of organ levels, especially the heart, which is expected to evaluate organ function and predict disease prognosis more accurately.

Performance of bone tracer for diagnosis and differentiation of transthyretin cardiac amyloidosis: a systematic review and meta-analysis

PURPOSE

Bone tracers have been validated for many years in detecting transthyretin cardiac amyloidosis (TTR-CA). However, several new studies suggest conflicting results. Our study aimed to systematically evaluate the accuracy of bone radiotracers for diagnosis and differentiation of TTR-CA via a systematic review and meta-analysis.

METHODS

We retrieved articles assessing the performance of bone tracer in diagnosing and differentiating TTR-CA from PubMed, the Cochrane Library, ScienceDirect, and DOAJ databases, dating up to 10 July 2020. The meta-analysis was conducted through Stata 16 software, and the risk of bias for the included studies was assessed by the QUADAS-2 tool. Moreover, we made a comprehensive review.

RESULTS

Fourteen articles were included in the systematic review, and 9 in the meta-analysis. The pooled sensitivity was 0.97 (95% confidence interval [95% CI] 0.85-0.99) with heterogeneity (I2=73.5, 95% CI 55.6-91.2), and the specificity was 0.92 (95% CI 0.82-0.96) with heterogeneity (I2=42.0, 95% CI 0.0-86.9). The pooled positive and negative likelihood ratios were 11.49 (95% CI 5.07-26.0) and 0.03 (95% CI 0.01-0.18), respectively. The diagnostic odds ratio was 341 (95% CI 53-2194), and the area under the receiver operating characteristic curve was 0.96 (95% CI 0.94-0.97).

CONCLUSION

The findings evidence that the bone radiotracer is a valuable noninvasive approach that provides high accuracy for diagnosing TTR-CA and plays a modest role in differentiating TTR-CA from immunoglobulin amyloid light-chain cardiac amyloidosis. 99mTc-HMDP may be more accurate than 99mTc-PYP, 99mTc-DPD, and 18F-NaF in the TTR-CA detecting process, and 18F-NaF is a promising bone tracer to diagnose and differentiate TTR-CA.

A real-world study on diagnosis and prognosis of light-chain cardiac amyloidosis in Southern China

Background

Light-chain cardiac amyloidosis (AL-CA) has been highly valued in developed countries, but in developing countries, the recognition and diagnosis of this condition is still limited. There are currently few reports on a large number of Chinese patients with AL-CA. The present study aimed to report real-world clinical characteristics and prognosis of AL-CA in China.

Methods and results

Consecutive patients with AL-CA diagnosed at the Second Xiangya Hospital of Central South University between June 2012 and September 2020 were reviewed. A total of 170 patients with AL-CA have been recruited, whose mean ages were 60.81 ± 10.46. 70.59% of the patients were male. They were from eight provinces in southern China, 55.7% were referred patients, and 37.3% had been misdiagnosed previously. 64 (37.6%) patients received chemotherapy. The median survival time for patients with AL-CA was 8.00 months, and survival time for patients who received chemotherapy was 13.00 months, which was significantly longer than that of patients with palliative treatment (13.00 vs 6.00, p = 0.004).

Conclusions

Although clinicians have improved their understanding of AL-CA in recent years, the prognosis of AL-CA is still poor, and the misdiagnosis rate and missed diagnosis rate are still very high in China. It is imperative to improve the recognition and early diagnosis of this condition, which may require multidisciplinary collaboration among cardiologists, hematologists and nephrologists.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02256-3.

Diagnostic performance of PET for detection of cardiac amyloidosis: A systematic review and meta-analysis

OBJECTIVES

The purpose of the current investigation was to evaluate the diagnostic accuracy of amyloid and F-18 sodium fluoride (NaF) positron emission tomography/computed tomography (PET/CT) for the detection of cardiac amyloidosis (CA) using diagnostic accuracy test.

MATERIALS AND METHODS

The PubMed, Cochrane, and EMBASE database, from the earliest available date of indexing through February 29, 2020, were searched for results investigating the diagnostic accuracy of amyloid and F-18 NaF PET for the diagnosis of CA. We calculated the pooled sensitivities and specificities of included studies, calculated positive and negative likelihood ratios (LR+ and LR-), and obtained summary receiver operating characteristic (SROC) curves.

RESULTS

Across 13 studies with 14 results (90 patients), the pooled sensitivity of amyloid PET was 0.97 and a pooled specificity was 0.98. The pooled sensitivity of F-18 NaF PET was 0.63 and a pooled specificity was 1.00. The pooled sensitivity of combined amyloid and F-18 NaF PET was 0.88 and a pooled specificity was 0.98.

CONCLUSION

Amyloid PET has a high sensitivity and specificity for the detection of CA. However, F-18 NaF PET showed relatively low sensitivity with high specificity. At present, the literature regarding the use of amyloid and F-18 NaF PET for diagnosis of CA is still limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of amyloid and F-18 NaF PET for detection of CA.

Quantification of 11C-PIB kinetics in cardiac amyloidosis

BACKGROUND

The purpose of this work was to determine the optimal tracer kinetic model of 11C-PIB and to validate the use of the simplified methods retention index (RI) and standardized uptake value (SUV) for quantification of cardiac 11C-PIB uptake in amyloidosis.

METHODS AND RESULTS

Single-tissue, reversible and irreversible two-tissue models were fitted to data from seven cardiac amyloidosis patients who underwent 11C-PIB PET scans and arterial blood sampling for measurement of blood radioactivity and metabolites. The irreversible two-tissue model (2Tirr) best described cardiac 11C-PIB uptake. RI and SUV showed high correlation with the rate of irreversible binding (Ki) from the 2Tirr model (r2 =0.95 and r2 =0.94). Retrospective data from 10 amyloidosis patients and 5 healthy controls were analyzed using RI, SUV, as well as compartment modelling with a population-average metabolite correction. All measures were higher in amyloidosis patients than in healthy controls (p=.001), but with an overlap between groups for Ki.

CONCLUSION

An irreversible two-tissue model best describes the 11C-PIB uptake in cardiac amyloidosis. RI and SUV correlate well with Ki from the 2Tirr model. RI and SUV discriminate better between amyloidosis patients and controls than Ki based on population-average metabolite correction.

Cardiac amyloidosis imaging with amyloid positron emission tomography: A systematic review and meta-analysis

BACKGROUND

Recent progress in amyloid positron emission tomography (PET) has enabled the targeted imaging of cardiac amyloidosis with accuracy. We performed a systematic review and meta-analysis on the diagnostic performance of cardiac amyloidosis using amyloid PET.

METHODS

A systematic search was performed using key words: cardiac amyloidosis, amyloid, and PET. We estimated the pooled sensitivity, specificity, positive and negative likelihood ratio (LR), and diagnostic odds ratio (DOR). Furthermore, the semiquantitative parameters of PET were evaluated to diagnose cardiac amyloidosis and discern its type [systemic light chain amyloidosis (AL) vs transthyretin amyloidosis (ATTR)] using the pooled standardized mean difference (SMD).

RESULTS

In total, six eligible studies with a total of 98 subjects were included in this meta-analysis. The pooled sensitivity was 0.95, the specificity was 0.98, positive LR was 10.130, negative LR was 0.1, and DOR was 148.83. The semiquantitative parameters of amyloid PET showed significantly higher values for cardiac amyloidosis patients than those for controls (pooled SMD = 1.42; P < .001), and in AL than ATTR (pooled SMD = 0.96; P < .001).

CONCLUSION

Amyloid PET imaging can be a useful method for diagnosing cardiac amyloidosis. The semiquantitative parameters of amyloid PET can help diagnose cardiac amyloidosis and discern its type.

Prognostic Significance of Holter Monitor Findings in Patients With Light Chain Amyloidosis

OBJECTIVE

To evaluate the prognostic impact of Holter findings in patients with light chain amyloidosis.

PATIENTS AND METHODS

We evaluated 239 patients in whom light chain amyloidosis was diagnosed from January 1, 2010, through December 31, 2015, who underwent 24-hour Holter monitoring.

RESULTS

Holter testing was done before stem cell transplant evaluation in 183 of the 239 patients (76.6%) and at diagnosis in 50 (20.9%). Holter findings were nonsustained ventricular tachycardia (NSVT) in 60 patients (25.1%), ventricular couplets in 103 (43.1)%, accelerated idioventricular rhythm in 32 (13.4%), and atrial fibrillation (AF) in 18 (7.5%). Overall survival (OS) at 3 and 6 months after Holter monitoring in patients with AF vs without AF was 78% (95% CI, 54%-91%) vs 96% (95% CI, 92%-98%) (P=.002) and 61% (95% CI, 38%-80%) vs 92% (95% CI, 87%-95%), (P<.001), respectively. In patients with and without NSVT, 3- and 6-month OS after Holter testing was 90% (95% CI, 80%-94%) vs 96% (95% CI, 91%-98%) (P=.12) and 77% (95% CI, 64%-85%) vs 94% (95% CI, 89%-97%) (P<.001), respectively. For patients with and without ventricular couplets, 3- and 6-month OS was 94% (95% CI, 88%-97%) vs 94% (95% CI, 89%-97%) (P=.98) and 84% (95% CI, 75%-89%) vs 94% (95% CI, 89%-97%) (P=.01), respectively. Atrial fibrillation (hazard ratio, 2.5; 95% CI, 1.2-5.0; P=.02) and NSVT (hazard ratio, 2.0; 95% CI, 1.1-3.5; P=.02) were independent predictors for OS after accounting for age and Mayo stage. For patients undergoing routine testing before stem cell transplant, AF (P=.002) and NSVT (P=.02) were associated with inferior OS at 6 months but did not retain statistical significance after adjusting for Mayo stage (P=.10 and P=.54, respectively).

CONCLUSION

Atrial fibrillation and NSVT on 24-hour Holter monitoring are associated with inferior short-term OS outcomes but do not impact peritransplant mortality.

Transthyretin Cardiac Amyloidosis in Older Adults: Optimizing Cardiac Imaging to the Corresponding Diagnostic and Management Goal

PURPOSE OF REVIEW

Transthyretin cardiac amyloidosis is increasingly recognized as an important cause of heart failure in older adults. Many cardiac imaging modalities have evolved to evaluate transthyretin cardiac amyloidosis and include 2D echocardiography with tissue Doppler and speckle-strain imaging, nuclear scintigraphy, cardiac magnetic resonance imaging, and positron emission tomography. The purpose of this review is to highlight the optimal selection of advanced cardiac imaging techniques with corresponding diagnostic goals including raising suspicion, making an early diagnosis, and subtyping transthyretin cardiac amyloid, as well as management goals including assessment of ventricular impairment, prognosticating, and monitoring disease progression. Potential benefits of optimizing cardiac imaging in the elderly patient with transthyretin cardiac amyloidosis may include enhanced and earlier diagnosis and refined long-term management.

RECENT FINDINGS

Advances in cardiac imaging techniques are changing diagnostic and management algorithms for transthyretin cardiac amyloidosis.

SUMMARY

With a new era of novel therapeutics, enhanced recognition, and earlier diagnosis approaching, selecting the appropriate non-invasive cardiac imaging modality will be essential for optimal care in the elderly patient with transthyretin cardiac amyloidosis.