Prognostic implications of biventricular uptake of bone tracers at planar scintigraphy in transthyretin cardiac amyloidosis

Background

The prognostic role of bone tracer uptake in transthyretin cardiac amyloidosis (ATTR-CA) is controversial. A further characterization of cardiac retention measured by Perugini scale with differentiation between biventricular (BiV) and isolated left ventricle (LV) uptake has never been attempted previously.

Purpose

The study investigated the potential prognostic significance of BiV uptake in ATTR-CA.

Methods

In this multicentre, observational study, we analysed data of ATTR-CA patients who underwent bone tracer scintigraphy with acquisition of both planar and single photon emission computed tomography (SPECT) imaging. Cardiac uptake was defined according to the Perugini visual scale. Planar BiV uptake was defined according to right ventricle (RV) uptake: 0= absent, 1= < bone, 2= equal to bone, and 3= > bone and confirmed by SPECT imaging. The primary outcome was a composite of cardiac death or hospitalization for heart failure. The secondary outcome was all-cause mortality.

Results

All 124 ATTR-CA patients enrolled had LV and RV free wall uptake on SPECT images. Of them, 93 (75%) had BiV uptake visible on planar scintigraphy. BiV uptake was found in 14%, 70%, and 92% of Perugini grade 1, 2 and 3 respectively. Compared to those with isolated LV uptake, patients with BiV uptake were older (81 vs 77 years, p=0.006) and more frequently in NYHA≥3 (32% vs 10%, p=0.018). During a median follow-up of 21 months, BiV uptake was associated with a greater occurrence of the primary outcome compared to isolated LV uptake (40% vs 19%, p=0.021), whereas the Perugini scale was not (p=0.2) (Figure 1). At multivariable analysis, NYHA class ≥3 (hazard ratio [HR] 8.1, p=0.007), eGFR <60 ml/min (HR 2.1, p=0.025) and higher degree of RV uptake (HR 1.69, p=0.007) emerged as independent prognostic parameters. In an external cohort of 463 ATTR-CA patients with a median follow-up of 30 months, planar BiV uptake was independently associated with all-cause mortality, with an incremental risk in higher grades of RV uptake (p<0.001) (Figure 1).

Conclusions

The presence of BiV uptake at planar scintigraphy identified ATTR-CA patients with worse cardiovascular and global outcomes (Figure 2), potentially serving as a novel prognostic marker.

Funding Acknowledgement

Type of funding sources: None.

Incidence and risk factors for pacemaker implantation in light chain and transthyretin cardiac amyloidosis

Background

The incidence and risk factors of pacemaker (PM) implantation in patients with cardiac amyloidosis (CA) are largely unexplored.

Purpose

We sought to characterise the trends in the incidence of permanent PM and to identify baseline predictors of future PM implantation in light chain (AL) and transthyretin (ATTR) CA.

Methods

Multicentre, retrospective, observational study. Consecutive patients with AL and ATTR-CA diagnosed or referred at participating Centres between 2017 and 2020 were included. Clinical data recorded within ± 1 month from baseline evaluation were collected from electronic medical records. The primary outcome of the study was the need for clinically-indicated PM implantation. Reversible causes of conduction system disease were systematically ruled out before PM implantation. Patients with PM (n=41) and/or permanent defibrillator in situ (n=13) at the time of CA diagnosis were excluded.

Results

The study population consisted of 405 patients: 29.4% AL, 14.6% variant ATTR and 56% wild-type ATTR; 82.5% were males, with median age 76 years. During a median follow-up of 33 months (interquartile range 21–46), 36 (8.9%) patients experienced the primary outcome: 10 patients with AL-CA, 2 with variant ATTR-CA and 24 with wild-type ATTR-CA (p=0.08). At multivariable analysis, history of atrial fibrillation (hazard ratio [HR] 3.80, p=0.002), PR interval (HR 1.013, p=0.002) and QRS >120 ms (HR 4.7, p=0.001) on baseline ECG were independently associated with PM implantation (Figure 1). In the individual patient, the contemporary presence of these 3 factors yielded the highest risk of PM implantation (HR 6.26, p=0.003).

Conclusion

In a large cohort of AL and ATTR-CA, the incidence of PM implantation was high accounting for ≈9% of patients in the 3 years following the diagnosis. History of atrial fibrillation, longer PR interval and QRS >120 ms identified CA patients at high-risk of future PM implantation (Figure 2).

CA patients with these features might need close monitoring during follow-up for the development of conduction system disease requiring PM implantation.

Funding Acknowledgement

Type of funding sources: None.

Quantifying geographical accessibility to cancer clinical trials in different income landscapes

Background

Clinical trials are increasingly perceived as a therapeutic opportunity for cancer patients. Favoring their concentration in few high-expertise academic centers maximizes quality of data collection but poses an issue of access equality. Analytical tools to quantify trial accessibility are needed to rationalize resources.

Materials and methods

We constructed a distance-based accessibility index (dAI) using publicly available data on demographics, cancer incidence and trials. Multiple strategies were applied to mitigate or quantify clear sources of bias: reporting biases by text mining multiple registries; reliability of simple geographical distance by comparison with high-quality travel cost data for Italy; index inflation due to highly heterogeneous cancer incidence by log-transformation. We studied inequalities by Gini index and time trend significance by Mann–Kendall test. We simulated different resource allocation models in representative countries and identified locations where new studies would maximally improve the national index.

Results

The dAI approximated well a more realistic but not widely applicable travel cost-based index. Accessibility was unevenly distributed across and within countries (Gini index ∼0.75), with maximal inequalities in high- and upper-middle-income countries (China, United States, Russian Federation). Over time, accessibility increased but less than the total number of trials, most evidently in upper-middle-income countries. Simulations in representative countries (Italy and Serbia) identified ideal locations able to maximally raise the national index.

Conclusions

Access to clinical trials is highly uneven across and within countries and is not mitigated by simple increase in the number of trials; a rational algorithmic approach can be used to mitigate inequalities.

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Accessibility to cancer clinical trials grew less than total number of trials over time in upper-middle-income countries.

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Accessibility is unevenly distributed, with maximal inequalities in high- and upper-middle-income countries.

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Simulation of resource allocation can identify ideal locations able to raise the national accessibility index.

Recommendations for pre-symptomatic genetic testing for hereditary transthyretin amyloidosis in the era of effective therapy: a multicenter Italian consensus

Hereditary transthyretin amyloidosis (ATTRv, v for variant) is a late-onset, autosomal dominant disease caused by progressive extracellular deposition of transthyretin amyloid fibrils, leading to organ damage and death. For other late-onset fatal diseases, as Huntington’s disease, protocols for pre-symptomatic genetic testing (PST) are available since decades. For ATTRv, limited experience has been reported to date, mostly gathered before the availability of approved therapies. We aimed at developing recommendations for a safe and feasible PST protocol in ATTRv in the era of emerging treatments, taking also into account Italian patients’ characteristics and healthcare system rules. After an initial survey on ongoing approaches to PST for ATTRv in Italy, two roundtable meetings were attended by 24 experts from 16 Italian centers involved in the diagnosis and care of this disease. Minimal requirements for PST offer and potential critical issues were highlighted. By November 2019, 457 families affected by ATTRv with 209 molecularly confirmed pre-symptomatic carriers were counted. The median age at PST was 41.3 years of age, regardless of the specific mutation. Half of the Italian centers had a multidisciplinary team, including a neurologist, an internist, a cardiologist, a medical geneticist and a psychologist, although in most cases not all the specialists were available in the same center. A variable number of visits was performed at each site. Experts agreed that PST should be offered only in the context of genetic counselling to at risk individuals aged 18 or older. Advertised commercial options for DNA testing should be avoided. The protocol should consist of several steps, including a preliminary clinical examination, a pre-test information session, an interval time, the genetic test and a post-test session with the disclosure of the test results, in the context of an experienced multidisciplinary team. Recommendations for best timing were also defined. Protocols for PST in the context of ATTRv can be refined to offer at risk individuals the best chance for early diagnosis and timely treatment start, while respecting autonomous decisions and promoting safe psychological adjustment to the genetic result.