Cardiovascular autonomic failure in hereditary transthyretin amyloidosis and TTR carriers is an early and progressive disease marker

BACKGROUND

The cardiomyopathic and neuropathic phenotype of hereditary transthyretin amyloidosis are well recognized. Cardiovascular autonomic dysfunction is less systematically and objectively assessed.

METHODS

Autonomic and clinical features, quantitative cardiovascular autonomic function, and potential autonomic prognostic markers of disease progression were recorded in a cohort of individuals with hereditary transthyretin amyloidosis and in asymptomatic carriers of TTR variants at disease onset (T0) and at the time of the first quantitative autonomic assessment (T1). The severity of peripheral neuropathy and its progression was stratified with the polyneuropathy disability score.

RESULTS

A total of 124 individuals were included (111 with a confirmed diagnosis of hereditary transthyretin amyloidosis, and 13 asymptomatic carriers of TTR variants). Symptoms of autonomic dysfunction were reported by 27% individuals at T0. Disease duration was 4.5 ± 4.0 years [mean ± standard deviation (SD)] at autonomic testing (T1). Symptoms of autonomic dysfunction were reported by 78% individuals at T1. Cardiovascular autonomic failure was detected by functional testing in 75% individuals and in 64% of TTR carriers. Progression rate from polyneuropathy disability stages I/II to III/IV seemed to be shorter for individuals with autonomic symptoms at onset [2.33 ± 0.56 versus 4.00 ± 0.69 years (mean ± SD)].

CONCLUSIONS

Cardiovascular autonomic dysfunction occurs early and frequently in individuals with hereditary transthyretin amyloidosis within 4.5 years from disease onset. Cardiovascular autonomic failure can be subclinical in individuals and asymptomatic carriers, and only detected with autonomic function testing, which should be considered a potential biomarker for early diagnosis and disease progression.

The role of cardiovascular autonomic failure in the differential diagnosis of α-synucleinopathies

The α-synucleinopathies comprise a group of adult-onset neurodegenerative disorders including Parkinson’s disease (PD), multiple system atrophy (MSA), dementia with Lewy bodies (DLB,) and — as a restricted non-motor form — pure autonomic failure (PAF). Neuropathologically, the α-synucleinopathies are characterized by aggregates of misfolded α-synuclein in the central and peripheral nervous system. Cardiovascular autonomic failure is a common non-motor symptom in people with PD, a key diagnostic criterion in MSA, a supportive feature for the diagnosis of DLB and disease-defining in PAF. The site of autonomic nervous system lesion differs between the α-synucleinopathies, with a predominantly central lesion pattern in MSA versus a peripheral one in PD, DLB, and PAF. In clinical practice, overlapping autonomic features often challenge the differential diagnosis among the α-synucleinopathies, but also distinguish them from related disorders, such as the tauopathies or other neurodegenerative ataxias. In this review, we discuss the differential diagnostic yield of cardiovascular autonomic failure in individuals presenting with isolated autonomic failure, parkinsonism, cognitive impairment, or cerebellar ataxia.

Neurogenic orthostatic hypotension in early stage Parkinson's disease: New insights from the first 105 patients of the BoProPark study

OBJECTIVES

The prevalence of neurogenic orthostatic hypotension (NOH, due to cardiovascular autonomic failure) at early stage of Parkinson's disease (PD) is unknown. The aims of this study are to prospectively evaluate in a cohort of PD patients recruited within 3 years from motor onset (1) cardiovascular autonomic functions by means of cardiovascular reflex tests (CRTs) and the occurrence of NOH; (2) the frequency of orthostatic symptoms with a validated questionnaire.

METHODS

We included the first 105 PD patients of the prospective "BoProPark" study. Each patient underwent CRTs (head up tilt test; Valsalva manoeuvre; deep breathing; cold face test and handgrip test) under continuous blood pressure monitoring according to standardized procedures and SCOPA-Aut questionnaire at baseline (T0) and after 16 months (T1). A group of 50 age- and sex-matched controls was used for comparison.

RESULTS

At T0 (mean age 61 ± 9 years, disease duration 19 ± 9 months) NOH was detected in 4/105 (3.8%) patients, whereas at T1 in 8/105 (7.6%). CRTs responses assessing sympathetic function were impaired at T0 in PD patients compared to controls and progressively worsened at T1. Only 1 patient at T0 and 3 at T1 with NOH reported orthostatic symptoms with low frequency, while the majority of patients reporting these symptoms did not have OH at testing.

CONCLUSIONS

Our prospective study shows that NOH is not common at early PD stage. Asymptomatic mild sympathetic impairment was observed at first evaluation and progressed with disease evolution. Secondary OH may account for the higher prevalence of OH in PD reported so far.

Screening indexes for cardiovascular autonomic failure in Parkinson's disease

Autonomic failure (AF) is a common source of orthostatic hypotension (OH) in Parkinson's disease (PD). The diagnosis of AF is difficult on clinical grounds alone. We used autonomic testing and 24-h BP monitoring (ABPM) in 122 PD patients to evaluate the diagnostic accuracy of AF by (1) the reduced heart rate increase to fall in blood pressure (BP) ratio (ΔHR/ΔSBP), (2) reverse dipping (RD), and (3) increased diurnal systolic BP standard deviation (SD-SBP). Among patients with OH, ΔHR/ΔSBP yielded the best accuracy (85%), with excellent sensitivity (92%) and acceptable specificity (67%). RD and, to a lesser extent, SD-SBP had high specificity (93% and 73%, respectively) but low sensitivity, resulting in overall moderate accuracy (66% and 55%, respectively). In patients with OH, the addition of ABPM indexes to ΔHR/ΔSBP did not result in a significant improvement of accuracy. In patients without OH, RD and SD-SBP may be useful showing an accuracy of 72% and 81%, respectively, with high negative predictive value when both RD and increased SD-SBP are absent. The integration of bedside (∆HR/∆SBP) and ABPM-derived indexes can assist the clinician in screening PD patients for AF and guide referral to autonomic testing.

Cardiovascular autonomic function testing in multiple system atrophy and Parkinson's disease: an expert-based blinded evaluation

PURPOSE

Multiple system atrophy (MSA) and Parkinson's disease (PD) are sporadic neurodegenerative diseases characterized by an accumulation of misfolded α-synuclein. Cardiovascular autonomic failure develops in both MSA and PD, although studies indicate different sites of autonomic nervous system lesion. However, it is unclear whether this could potentially aid the differential diagnosis of these diseases. Here we determined whether cardiovascular autonomic function testing (CAFT) can discriminate between the parkinsonian variant of MSA (MSA-P) and PD based on either an expert-based blinded evaluation or a systematic comparison of cardiovascular autonomic function indices.

METHODS

We included 22 patients aged 55-80 with neurogenic orthostatic hypotension (nOH) who had been diagnosed with either clinically probable MSA-P (n = 11) according to current consensus criteria or clinically definite PD (n = 11) according to the Queen Square criteria. Three physicians with expertise in CAFT were blinded to the neurological diagnosis and were asked to identify the correct neurological diagnosis by applying a self-created evaluation scheme to the CAFT recordings. Afterwards, a systematic comparison of clinical-demographic characteristics and CAFT parameters was carried out.

RESULTS

Neither the raters (overall diagnostic accuracy: 58.46%) nor the evaluation scheme created post hoc (72.73%) showed reliable discriminatory capacity. The inter-rater reliability was slight (κ = 0.01). We observed no statistically significant differences in cardiovascular autonomic indices between PD and MSA-P patients.

CONCLUSION

CAFT is the gold standard for assessing the presence and severity of cardiovascular autonomic failure, but the results of our pilot study suggest that CAFT might be of limited value in the differential diagnosis between MSA-P and PD once nOH is present.

Cardiovascular dysfunction in untreated Parkinson's disease: A multi-modality assessment

BACKGROUND

The clinical presentation of Parkinson's disease (PD) includes a wide spectrum of non-motor features, including cardiovascular autonomic failure.

OBJECTIVE

To evaluate cardiovascular autonomic status and cardiac functional capacity in drug-naïve PD patients.

METHODS

18 newly-diagnosed PD patients underwent laboratory cardiovascular autonomic function tests using power spectral analysis of the R-R interval, blood pressure (BP) short-term variability and non-invasive baroreflex sensitivity (BRS). A two-dimensional (2D) transthoracic echocardiogram, spirometry and cardiopulmonary exercise test (CPET) were also performed. Thirteen patients underwent myocardial scintigraphy with [¹²³I] metaiodobenzylguanidine (MIBG).

RESULTS

At rest, total power spectral analysis of heart rate variability was lower in PD patients than in controls. BRS decreased during sympathetic activation in both patients and controls. While echocardiography and spirometry were normal, a mild degree of exercise intolerance was observed at the CPET in PD patients (mean V'O_2max: 83% of predicted; mean W_max: 80% of predicted). The heart-to-mediastinum (H/M) ratio of MIBG uptake was pathologically impaired in 9 patients, one of whom displayed a definite cardiovascular dysautonomic pattern.

CONCLUSIONS

Our results confirm that subclinical to overt cardiovascular autonomic failure may occur from the early stages of PD. The less efficient adaptive response to physical stimuli during the CPET and postural changes observed in untreated PD patients possibly reflect cardiac sympathetic denervation, although the involvement of PD-related motor impairment in physical deconditioning cannot be excluded.