The Impact of Iron Deficiency on Disease Severity and Myocardial Function in Cardiac Amyloidosis.

Background: Reduced cardiac energy is a hallmark feature of heart failure and is common in cardiac amyloidosis (CA) and can be aggravated by the presence of iron deficiency. Methods: Retrospective analysis of a single tertiary care center CA registry. Prevalence of iron deficiency was determined based on two definitions: (1) Classic definition, ferritin < 100 µg/L irrespective of transferin saturation (TSAT) or ferritin between 100 and 300 µg/L with a TSAT < 20%, and (2) TSAT-based definition, TSAT < 20%. Results: Out of a total of 393 CA patients who had a full set of iron indices (44% light chain [AL]-CA, 50% transthyretin [ATTR]-CA, remainder other or unspecified CA subtype), 56% had iron deficiency according to the classic definition and 58% according to the TSAT definition, with similar prevalence in AL-CA vs ATTR-CA (p = .135). Per both definitions 58% had anemia. Only the TSAT-based definition was associated with worse functional status (p = .039) and worse cardiac function. CA patients with a TSAT < 20% illustrated features of more pronounced right ventricular (RV) failure including lower TAPSE on echocardiography, lower RV ejection fraction and RV stroke volume index on CMR, increased right-sided filling pressures, lower pulmonary artery pulsatility index, and higher RAP/PCWP ratio by right heart catheterization. Neither the classic nor the TSAT-based definition was associated with a higher risk of all-cause mortality after covariate adjustment. Conclusion: Iron deficiency is common in cardiac amyloidosis and, when identified with a TSAT < 20%, is associated with worse functional status and more pronounced RV disease, but not with a higher risk of all-cause mortality.

Long-term tafamidis efficacy in patients with transthyretin amyloid cardiomyopathy by baseline left ventricular ejection fraction.

AIMS: Patients with transthyretin amyloid cardiomyopathy (ATTR-CM) present with diverse left ventricular ejection fraction (LVEF). This study assessed tafamidis efficacy by baseline LVEF in the phase 3 Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and its long-term extension (LTE) study. METHODS AND RESULTS: Patients were randomized to 30 months of tafamidis or placebo treatment in ATTR-ACT. On completion, patients could join an LTE study to receive tafamidis. All-cause mortality (death, heart transplant, or cardiac mechanical assist device implantation) from baseline to the end of follow-up was assessed in patients continuously treated with tafamidis (80 mg meglumine or 61 mg free acid) or delayed tafamidis treatment (placebo in ATTR-ACT; tafamidis in the LTE study) according to baseline LVEF (<50% or ≥50%). Supportive outcomes were evaluated over a shorter follow-up. Patients with baseline LVEF <50% (n = 177: 88 tafamidis- and 89 placebo-treated) had signs of more severe heart failure, a higher proportion were Black, and had variant ATTR-CM than those with LVEF ≥50% (n = 171: 85 tafamidis- and 86 placebo-treated). At the end of follow-up (median 60-64 months), all-cause mortality was numerically higher in patients with baseline LVEF <50%; however, consistent with supportive findings, continuous tafamidis treatment was associated with a 47% reduction in mortality risk compared with delayed tafamidis treatment in patients with LVEF <50% and ≥50% (hazard ratio 0.53 [95% confidence interval 0.367-0.758]; p < 0.001, and 0.53 [0.344-0.818]; p < 0.01, respectively). CONCLUSIONS: Early initiation of tafamidis is associated with reduced mortality in patients with ATTR-CM, irrespective of initial LVEF value. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT01994889, NCT02791230.

Advancing Transthyretin Amyloidosis Drug Development in an Evolving Treatment Landscape: Amyloidosis Forum Meeting Proceedings.

INTRODUCTION: Hereditary transthyretin amyloidosis (ATTRv, also referred to as hATTR; ORPHA 271861) and wild-type ATTR amyloidosis (ATTRwt; ORPHA 330001) are rare, progressive, systemic protein misfolding disorders with heterogeneous clinical presentations. ATTRv and ATTRwt amyloidosis are characterized by the deposition of amyloid fibrils in multiple organs including the heart, nerves, eyes, and soft tissues. The management of ATTR amyloidosis is complex because of its multisystemic nature and progression despite available treatment options. Morbidity is high and there are many unmet medical needs for patients. While contemporary ATTR amyloidosis cohorts are diagnosed earlier, have lower risk disease and lower mortality compared with the previous era, these advances coupled with the emergence of effective disease-modifying therapies have confounded the design of future prospective clinical trials and interpretation of historical control data. MAIN BODY: The Amyloidosis Forum is a public-private partnership between the US Food and Drug Administration Center for Drug Evaluation and Research and the nonprofit Amyloidosis Research Consortium ( www.arci.org ). This article summarizes proceedings from the 21 June 2023 Amyloidosis Forum on advancing drug development in ATTR amyloidosis in an evolving treatment landscape. The Forum focused on elements of clinical trial design to address these challenges and discussed their strengths and weaknesses from multiple stakeholder perspectives (i.e., patient, sponsor, statistician, clinician, and regulatory authorities). CONCLUSION: Given rapid evolution of natural history in ATTR amyloidosis, the utility of historical control data is limited. Leveraging contemporary real-world data is essential for clinical trial design. Evidence generation from clinical trials should address clinically relevant questions. Key factors in successful trial design must be informed by up-to-date data on natural history, prognostic factors, clinically meaningful thresholds, and sharing available clinical trial data. The Amyloidosis Forum includes the community of patients with ATTR amyloidosis, the physicians who treat them, and the sponsors and regulators who collectively stand ready to support further studies in order to develop novel effective therapies.

Pericardial Disease in Cardiac Amyloidosis: A Comprehensive Review.

In patients with cardiac amyloidosis, pericardial involvement is common, with up to half of patients presenting with pericardial effusions. The pathophysiological mechanisms of pericardial pathology in cardiac amyloidosis include chronic elevations in right-sided filling pressures, myocardial and pericardial inflammation due to cytotoxic effects of amyloid deposits, and renal involvement with subsequent uremia and hypoalbuminemia. The pericardial effusions are typically small; however, several cases of life-threatening cardiac tamponade with hemorrhagic effusions have been described as a presenting clinical scenario. Constrictive pericarditis can also occur due to amyloidosis and its identification presents a clinical challenge in patients with cardiac amyloidosis who concurrently manifest signs of restrictive cardiomyopathy. Multimodality imaging, including echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging, is useful in the evaluation and management of this patient population. The recognition of pericardial effusion is important in the risk stratification of patients with cardiac amyloidosis as its presence confers a poor prognosis. However, specific treatment aimed at the effusions themselves is seldom indicated. Cardiac tamponade and constrictive pericarditis may necessitate pericardiocentesis and pericardiectomy, respectively.

Effect of long-term tafamidis treatment on health-related quality of life in patients with transthyretin amyloid cardiomyopathy.

AIMS: To evaluate the effect of long-term tafamidis treatment on health-related quality of life (HRQoL) in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) enrolled in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and long-term extension (LTE) study. METHODS AND RESULTS: We examined change from baseline in Kansas City Cardiomyopathy Questionnaire overall summary (KCCQ-OS) and clinical summary (KCCQ-CS) scores in patients who received tafamidis meglumine 80 mg for 30 months in ATTR-ACT and tafamidis (meglumine 80 mg or bioequivalent free acid 61 mg) for 30 months in the LTE study, and in patients who received placebo for 30 months in ATTR-ACT and tafamidis for 30 months in the LTE study. In ATTR-ACT, 176 and 177 patients were randomized to tafamidis 80 mg and placebo, respectively. Patients who continuously received tafamidis had a 6- to 7-point reduction in least squares (LS) mean (standard error) KCCQ-OS and KCCQ-CS scores at month 30 (-6.25 [1.53] and -7.48 [1.39]), with little or no further decline over the next 30 months (-5.92 [1.77] and -9.21 [1.88] at month 60). Patients who received placebo in ATTR-ACT had a 20-point reduction in LS mean KCCQ-OS and KCCQ-CS scores at month 30 (-19.60 [1.94] and -19.90 [2.01]), but the decline slowed after initiating tafamidis (-24.70 [3.04] and -25.30 [3.36] at month 60). CONCLUSION: Tafamidis reduced HRQoL decline in patients with ATTR-CM. Patients continuously treated with tafamidis for 60 months demonstrated stabilized HRQoL. In patients who initially received placebo in ATTR-ACT, tafamidis reduced the decline in HRQoL during the LTE study.

Outcomes of Octogenarian Patients Treated with Tafamidis for Transthyretin Amyloid Cardiomyopathy.

Patients with transthyretin amyloid cardiomyopathy (ATTR-CM) benefit from disease-modifying agents such as tafamidis. However, the survival benefit of tafamidis in elderly patients (age ≥80 years) is not reported. This study aimed to assess the survival of patients with ATTR-CM aged 80 years and older who were treated with tafamidis compared with patients aged <80 years. We conducted a retrospective analysis of patients with ATTR-CM who underwent tafamidis treatment, aged 45 to 97 years at the time of diagnosis between January 1, 2008, and May 31, 2021. A total of 484 patients were included, with 208 in the ≥80 years group and 276 in the <80 years group. The cohort was followed up for mortality outcomes, and hazard ratios with 95% confidence intervals were calculated. After a median follow-up of 18.5 months, 72 deaths were recorded in the entire cohort. Kaplan-Meier curves showed no differences in survival probability between the 2 groups at 30 months (p for log-rank test = 0.76). The survival rates for patients aged ≥80 years who underwent treatment at 1, 2, 3, 4, and 5 years were 94.7%, 86.0%, 77.0%, 77.0%, and 38.5%, respectively. The corresponding rates for patients aged <80 years who underwent treatment were 93.2, 84.8, 74.4, 68.2, and 64.6%, respectively. In the multivariable analysis, the hazard ratio (95% confidence interval) of the mortality comparing treatment patients aged ≥80 years with those aged <80 years was 0.81 (0.41 to 1.61). In conclusion, tafamidis treatment is associated with similar reductions in mortality in older and younger patients with ATTR-CM.

Efficacy and Safety of Acoramidis in Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: Transthyretin amyloid cardiomyopathy is characterized by the deposition of misfolded monomeric transthyretin (TTR) in the heart. Acoramidis is a high-affinity TTR stabilizer that acts to inhibit dissociation of tetrameric TTR and leads to more than 90% stabilization across the dosing interval as measured ex vivo. METHODS: In this phase 3, double-blind trial, we randomly assigned patients with transthyretin amyloid cardiomyopathy in a 2:1 ratio to receive acoramidis hydrochloride at a dose of 800 mg twice daily or matching placebo for 30 months. Efficacy was assessed in the patients who had an estimated glomerular filtration rate of at least 30 ml per minute per 1.73 m2 of body-surface area. The four-step primary hierarchical analysis included death from any cause, cardiovascular-related hospitalization, the change from baseline in the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, and the change from baseline in the 6-minute walk distance. We used the Finkelstein-Schoenfeld method to compare all potential pairs of patients within strata to generate a P value. Key secondary outcomes were death from any cause, the 6-minute walk distance, the score on the Kansas City Cardiomyopathy Questionnaire-Overall Summary, and the serum TTR level. RESULTS: A total of 632 patients underwent randomization. The primary analysis favored acoramidis over placebo (P<0.001); the corresponding win ratio was 1.8 (95% confidence interval [CI], 1.4 to 2.2), with 63.7% of pairwise comparisons favoring acoramidis and 35.9% favoring placebo. Together, death from any cause and cardiovascular-related hospitalization contributed more than half the wins and losses to the win ratio (58% of all pairwise comparisons); NT-proBNP pairwise comparisons yielded the highest ratio of wins to losses (23.3% vs. 7.0%). The overall incidence of adverse events was similar in the acoramidis group and the placebo group (98.1% and 97.6%, respectively); serious adverse events were reported in 54.6% and 64.9% of the patients. CONCLUSIONS: In patients with transthyretin amyloid cardiomyopathy, the receipt of acoramidis resulted in a significantly better four-step primary hierarchical outcome containing components of mortality, morbidity, and function than placebo. Adverse events were similar in the two groups. (Funded by BridgeBio Pharma; ATTRibute-CM ClinicalTrials.gov number, NCT03860935.).

Race, Genotype, and Prognosis in Black Patients With Transthyretin Cardiac Amyloidosis.

Previous studies suggest worse outcomes in patients with variant transthyretin cardiac amyloidosis (ATTR-CA) because of valine-to-isoleucine substitution at Position 122 (V122I) (ATTRv-CA) compared with patients with wild-type (WT) disease (ATTRwt-CA). Given V122I is almost exclusively found in Black patients, it is unclear if this is attributable to the biology of genotype or racial differences. Patients with ATTR-CA diagnosed between January 2001 and August 2021 were characterized into 3 categories: (1) White with ATTRwt-CA (White-WT); (2) Black with V122I ATTRv-CA (Black-V122I), and (3) Black with ATTRwt-CA (Black-WT). Event-free survival (composite of death, left ventricular assist device, or cardiac transplant) was evaluated using univariable and multivariable analyses over a median follow-up of 1.6 (0.7 to 2.90) years. Of 694 ATTR-CA patients, 502 (72%) were White-WT, 139 Black-V122I (20%), and 53 Black-WT (8%). Notably, 28% of Black patients with ATTR-CA had WT disease and not the V122I variant. Using multivariable modeling to adjust for several prognostic features, Black-V122I had higher risk of the composite adverse outcome compared with a grouped cohort of patients with WT disease (White-WT and Black-WT) (hazard ratio [HR] 1.82, confidence interval [CI] 1.30-2.56, p < 0.001). Furthermore, the Black cohort as a whole (Black-V122I and Black-WT) demonstrated greater risk of adverse outcomes compared with White-WT (HR 1.63, CI 1.19-2.24, p = 0.002). Black-V122I had greater risk of the primary end point compared with White-WT (HR 1.80, CI 1.27-2.56, p = 0.001). Black patients with ATTR-CA have worse event-free survival than White-WT despite risk adjustment. However, it remains unclear whether this is driven by differences in race or genotype given the smaller number of Black-WT patients. Approximately one-quarter of Black patients had WT, of which a greater proportion were female compared with White-WT.

Tafamidis Efficacy Among Octogenarian Patients in the Phase 3 ATTR-ACT and Ongoing Long-Term Extension Study.

BACKGROUND: Tafamidis was approved to treat patients with transthyretin amyloid cardiomyopathy (ATTR-CM) on the basis of findings from the phase 3 Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT). OBJECTIVES: This study was a post hoc analysis exploring tafamidis efficacy in octogenarian patients. METHODS: Analysis of patients aged <80 and ≥80 years in ATTR-ACT and its ongoing open-label long-term extension (LTE) study, where all patients receive tafamidis. RESULTS: After 30 months in ATTR-ACT, least squares (LS) mean change from baseline in 6-minute walk test (6MWT) distance, N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration, and Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS) score were smaller (all P < 0.05) in patients aged ≥80 years treated with tafamidis (n = 51) vs placebo (n = 37). At the LTE study interim analysis, patients aged ≥80 years treated continuously with tafamidis had a smaller decline in KCCQ-OS score (P < 0.05) and trended toward longer median survival (45 vs 27 months; all-cause mortality HR: 0.6828 [95% CI: 0.4048-1.1517]; P = 0.1526) than those initially treated with placebo in ATTR-ACT. Similar efficacy was observed in patients aged <80 years in ATTR-ACT, including smaller LS mean change from baseline in 6MWT distance, NT-proBNP concentration, and KCCQ-OS score, and lower rate of cardiovascular-related hospitalizations with tafamidis (n = 125) vs placebo (n = 140). In the LTE study, patients aged <80 years treated continuously with tafamidis had a longer median survival (80 vs 41 months; HR = 0.4513 [95% CI: 0.3176-0.6413]; P < 0.0001) and a smaller decline in KCCQ-OS score than those initially treated with placebo. CONCLUSIONS: The findings demonstrate tafamidis efficacy for patients with ATTR-CM both in those aged <80 and those aged ≥80 years. (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial [ATTR-ACT]; NCT01994889/Long-term Safety of Tafamidis in Subjects With Transthyretin Cardiomyopathy; NCT02791230).

Changes in Left Ventricular Ejection Fraction and Clinical Trajectories of Transthyretin Cardiac Amyloidosis with Systolic Dysfunction.

BACKGROUND: Transthyretin cardiac amyloidosis (ATTR-CM) is classically thought of as a progressive disease with preserved systolic function. The longitudinal clinical trajectories of ATTR-CM with impaired left ventricular ejection fraction (LVEF) remain unclear. METHODS: This is a single-center retrospective cohort study of consecutive patients with ATTR-CM who underwent two or more echocardiograms with baseline LVEF < 50%. Patients were stratified according to the presence of ≥5% change in LVEF. A Cox proportional hazard model examined hazard of a composite outcome of death, transplant, or LVAD insertion over the two years following diagnosis. RESULTS: In our study cohort of 179 patients, 62 patients (34.6%) experienced an increase in LVEF while 33 (18.4%) experienced a decrease in LVEF. After adjusting for covariates, patients with a decrease in EF experienced increased hazard of death (HR 2.15, 95% CI 1.05-4.40, p = 0.038) compared to those with stable or an increase in LVEF. Changes in LVEF corresponded with significant differences in NT proBNP trajectories, but initial biomarker levels or clinical staging were not predictive of LVEF trajectory. CONCLUSIONS: in ATTR-CM patients with impaired LVEF, over a third demonstrated improved LVEF over time, while those with a decrease in LVEF had worse long-term outcomes.

Prognostic Utility of Left Atrial Strain to Predict Thrombotic Events and Mortality in Amyloid Cardiomyopathy.

BACKGROUND: There is currently no thromboembolic risk stratification tool for amyloid cardiomyopathy (ACM) and the current survival staging systems for ACM have only modest discriminatory ability. OBJECTIVES: This study aims to evaluate the prognostic value of left atrial (LA) strain to predict incident thrombotic event (TE) and improve survival staging systems in ACM. METHODS: The authors identified patients with light chain (AL) or transthyretin (ATTR) ACM and no history of atrial fibrillation (AF) at diagnosis. Three components of LA strain (reservoir, conduit, and contractile) were measured and their predictive value for TE and mortality was determined. In addition, the authors evaluated the incremental utility of adding LA strain to current prognostic staging systems. RESULTS: The authors included 448 patients (50.2% AL; 49.8% ATTR) with median follow-up of 3.8 years. There were 64 (14.3%) TE cases, 103 (23%) AF cases, and 234 (52.2%) deaths. Notably, 75% of TEs occurred without preceding AF documented. LA strain reservoir and LA contractile strain significantly predicted both events: HRs for TE were 2.22 (95% CI: 1.27-3.85; P = 0.006) and 2.63 (95% CI: 1.25-5.00; P = 0.01) per SD decrease in LA strain reservoir and LA contractile strain, respectively. The respective HRs for mortality were 1.32 (95% CI: 1.09-1.59; P < 0.001) and 1.49 (95% CI: 1.22-1.75; P < 0.001). Also, LA strain reservoir and LA contractile strain significantly improved the C-statistics of the Mayo AL staging from 0.65 to 0.68 and 0.70, respectively (P ≤ 0.02); Mayo ATTR staging (0.73 to 0.79 and 0.80, respectively; P < 0.001); and Gillmore ATTR staging (0.70 to 0.79 and 0.80, respectively; P < 0.001). CONCLUSIONS: LA strain identifies ACM patients with high thrombotic risk (independent of AF) and improves current ACM-specific survival staging.

Prevalence of ATTR-CA and high-risk features to guide testing in patients referred for TAVR.

PURPOSE: Transthyretin cardiac amyloidosis (ATTR-CA) is thought to be prevalent in patients with severe aortic stenosis (AS) who are referred for transcatheter aortic valve replacement (TAVR). However, prior studies were published when TAVR was only offered to elderly, inoperable, and high-risk patients. The aim of this study was to reevaluate the prevalence of ATTR-CA in a contemporary TAVR population and identify high-risk features to guide referral for technetium-99 pyrophosphate scan (99mTc-PyP scan) screening. METHODS: Patients seen in a multidisciplinary TAVR clinic for severe AS 70 years and older were referred for a 99mTc-PyP scan to evaluate for ATTR-CA. The primary outcome was the percent with a positive scan. The discriminatory ability of high-risk features was assessed to develop a more judicious screening system. RESULTS: Over the study period, 380 patients underwent screening, and 20 patients (5.3%) had a positive scan, with 17 patients having confirmed ATTR-CA, 1 patient deferring confirmatory testing (combined 4.7%), 1 having light chain amyloidosis, and 1 negative on biopsy. Compared to other patient and echocardiographic measures, elevated NT-pro BNP (> 1000 ng/L) was the best discriminator on who should be referred for 99mTc-PyP scan screening, with a sensitivity of 90% and a negative predictive value of 99%. CONCLUSION: The prevalence of ATTR-CA may be lower in a contemporary TAVR population due to its expanded indication for low-risk patients. NT-pro BNP is a simple test that can improve screening yield and more judiciously guide screening for ATTR-CA in this at-risk population. Comparison of the original versus the proposed algorithm.

Association of Tafamidis With Health Status in Patients With ATTR Cardiac Amyloidosis: A Post Hoc Analysis of the ATTR-ACT Randomized Clinical Trial.

Importance: Tafamidis reduced all-cause mortality and cardiovascular-related hospitalizations and minimized patient-reported health status deterioration at 30 months in patients with transthyretin (ATTR) amyloidosis. However, the clinical significance of health status changes remains unclear, particularly in patients with New York Heart Association (NYHA) class III symptoms who experienced more cardiovascular-related hospitalizations than those with NYHA class I-II symptoms. Objective: To evaluate the health status of patients taking tafamidis with baseline NYHA class III symptoms. Design, Setting, and Participants: This randomized clinical trial post hoc analysis evaluated data for patients with transthyretin (ATTR) cardiac amyloidosis and NYHA class I-III symptoms at baseline who were enrolled in ATTR-ACT, a placebo-controlled study of tafamidis held at 48 sites in 13 countries. Interventions: Tafamidis meglumine, 80 mg or 20 mg (pooled cohort), vs placebo. Main Outcomes and Measures: Established thresholds for clinical benefit on the Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS) were used to define response groups (very large decline to very large improvement); the proportion of patients in each group was calculated within each baseline NYHA class. Results: Among 441 patients (264 tafamidis, 177 placebo), the mean (SD) age was 74.3 (7.0) years; 398 (90%) were male and 43 (10%) were female. Mean (SD) baseline KCCQ-OS scores were 67.3 (21.4) in the tafamidis group and 65.9 (21.7) in the placebo group (range: 0-100, with 100 indicating the best health). There was a significant shift toward better KCCQ-OS scores in patients receiving tafamidis (odds ratio for 10-point improvement 2.4; 95% CI, 1.6-3.4; P < .001). More patients taking tafamidis were alive and not worse at all time points (37% vs 15% at month 30). These findings were similar in patients with NYHA class III symptoms. In patients with NYHA class III symptoms alive at 30 months, improvements in health status were more common (35% vs 10%) and declines were less common (38% vs 57%) with tafamidis vs placebo. Conclusions and Relevance: In ATTR-ACT, although patients with baseline NYHA class III symptoms had worse overall outcomes, treatment with tafamidis yielded better health status compared with placebo. Trial Registration: ClinicalTrials.gov Identifier: NCT01994889.

Significance of Pulmonary Hypertension in Cardiac Amyloidosis.

Pulmonary hypertension (PH) portends a poor prognosis in chronic heart failure and within distinct cardiomyopathies. There is a paucity of data on the impact of PH in patients with light-chain (AL) and transthyretin (ATTR) cardiac amyloidosis (CA). We sought to define the prevalence and significance of PH and PH subtypes in CA. We retrospectively identified patients with a diagnosis of CA who underwent right-sided cardiac catheterization (RHC) from January 2000 to December 2019. PH was defined as mean pulmonary artery pressure >20 mm Hg. PH was phenotyped as precapillary PH (PC-PH; pulmonary capillary wedge pressure [PCWP] <15, pulmonary vascular resistance [PVR] ≥3), isolated postcapillary PH (IpC-PH; PCWP >15, PVR <3), and combined postcapillary and precapillary PH (CpC-PH; PCWP >15 and PVR ≥3). Survival was assessed in those with CA and PH and for PH phenotypes. A total of 132 patients were included, 69 with AL CA and 63 with ATTR CA. A total of 75% (N = 99) had PH (76% of patients with AL and 73% of patients with ATTR, p = 0.615) and the predominant PH phenotype was IpC-PH. The degree of PH was comparable between ATTR CA and AL CA, and PH was observed in advanced stage disease (National Amyloid Center or Mayo stage II or greater). The overall survival for patients with CA and PH was similar to to those without PH. Higher mean pulmonary artery pressure independently predicted mortality in CA with PH (odds ratio 1.06, confidence interval 1.01 to 1.12, p = 0.03). In conclusion, PH was seen frequently in CA and tended to be IpC-PH; however, its presence did not significantly impact survival.

Predictive Modeling to Assess Pretest Probability of Transthyretin Gene Variants Based on Demographic Information.

BACKGROUND: Transthyretin amyloid cardiomyopathy (ATTR-CM) is a morbid condition, though recent advances in diagnosis and therapy stand to change its natural history. Patients' TTR genotype may guide family screening as more treatments and preventive strategies become available. An efficient, intuitive means of determining pretest genetic risk may better inform patients/clinicians when pursuing genetic testing. METHODS: This is a cohort study of 767 consecutive patients diagnosed with ATTR-CM who underwent genetic testing. Classification and regression trees (CART) analysis created a decision tree assessing likelihood of carrying a pathologic TTR gene variant. Age, sex, and race were used as independent variables. Logistic regression was also performed to model probability of pathologic TTR genotype. The primary outcome was the decision tree's accuracy in 2 separate institutions' ATTR-CM registry. RESULTS: In our study cohort, 208 patients (27.1%) had ATTRv. Race has served most efficiently as the root node followed by age and sex in a CART algorithm, and showed 88.2% accuracy (75.3% sensitivity, 93.9% specificity) in the validation cohort. The odds of having a TTR gene variant were greater in Black patients compared with non-Black patients (OR, 34.6 [95% CI, 20.5-58.3]; P<0.001). Non-Black patients with ATTR-CM aged 69 years and older had <4% risk of having a predisposing mutation. CONCLUSIONS: This CART algorithm incorporating age, sex, and race was able to determine which patients with ATTR-CM have pathogenic TTR mutations with high specificity. Non-Black patients diagnosed at age 69 years or older with ATTR-CM have a low likelihood to have ATTRv.