Widespread cardiovascular autonomic dysfunction in primary amyloidosis: does spontaneous hyperventilation have a compensatory role against postural hypotension?

OBJECTIVE: To investigate the possible causes of abnormal blood pressure control in light chain related (primary, AL) amyloidosis. DESIGN: Cardiovascular, autonomic, and respiratory response to passive tilting were investigated in 51 patients with primary amyloidosis (mean (SEM) age 56 (2) years) and in 20 age matched controls. Spontaneous fluctuations in RR interval, respiration, end tidal carbon dioxide, blood pressure, and skin microcirculation were recorded during supine rest and with tilting. The values were subjected to spectral analysis to assess baroreflex sensitivity and the autonomic modulation of cardiac and vascular responses. SETTING: Tertiary referral centre. RESULTS: Autonomic modulation of the heart and blood pressure was nearly absent in the patients with amyloidosis: thus baroreflex sensitivity and the low frequency (0.1 Hz) fluctuations in all cardiovascular signals were severely reduced (p < 0.01 or more), as were respiratory fluctuations in the RR interval, and no change was observed upon tilting. Despite reduced autonomic modulation, blood pressure remained relatively stable in the amyloid group from supine to tilting. End tidal carbon dioxide was reduced in the amyloid patients (p < 0.001) indicating persistent hyperventilation; the breathing rate correlated inversely with the fall in blood pressure on tilting (p < 0.05). CONCLUSIONS: In primary amyloidosis, pronounced abnormalities in arterial baroreflexes and cardiovascular autonomic modulation to the heart and the vessels may be partly compensated for by hyperventilation at a slow breathing rate.

Holter monitoring in AL amyloidosis: prognostic implications.

The heart is involved in more than one third of patients with primary (AL) amyloidosis at diagnosis and it is by far the most common cause of death. Rhythm and conduction abnormalities generally represent the terminal event. The aims of this study were to determine the spectrum of Holter abnormalities found in AL amyloidosis and to assess their prognostic significance, particularly in relation to sudden death. Fifty-one patients with AL amyloidosis were included, and all of them had a complete history, physical examination, two-dimensional echocardiography, and 24-hour Holter monitoring. Fifty-five percent of these patients had echographic signs of heart involvement and 23% had heart failure. Complex ventricular arrhythmias were found in 57% of patients, couplets in 29%, and nonsustained ventricular tachycardia in 18%. Overall median survival was 23.4 months. Congestive heart failure, echocardiographic abnormalities, and Holter abnormalities adversely affected survival. The multivariate analysis demonstrated that interventricular septum thickness and couplets were independent predictors of survival. The presence of couplets correlated with sudden death. Holter monitoring may contribute to assessing the prognosis of patients with AL amyloidosis.

A modified high-dose dexamethasone regimen for primary systemic (AL) amyloidosis.

High-dose dexamethasone (HD-Dex) has been reported to benefit AL amyloidosis patients with varying response rates. Our preliminary experience with the usual HD-Dex schedule indicated that the induction phase was rather toxic in AL patients. We therefore adopted a milder schedule consisting of dexamethasone 40 mg on d 1-4 q21 d for up to eight cycles. Overall 8 out of 23 (35%) treated patients responded to treatment in a median time of 4 months (range 2-6 months) without significant toxicity. This regimen may be considered front-line therapy when autologous stem cell transplantation is not feasible and when a rapid response is particularly important.

Clotting alterations in primary systemic amyloidosis.

BACKGROUND AND OBJECTIVE: The bleeding manifestations frequently observed in patients with immunoglobulin light chain amyloidosis (AL) have been attributed to different pathogenetic factors: amyloid deposits in several organs and systems leading to failures of these latter, the affinity of amyloid for some clotting factors, and the presence of plasma components interfering with fibrin formation could all induce alterations of clotting tests. This investigation was aimed at defining the prevalence of clotting abnormalities and their clinical manifestations in patients with AL. DESIGN AND METHODS: Thirty-six consecutive patients with biopsy proven amyloidosis and documented monoclonal gammapathy were enrolled within one year. The following clotting tests were considered in the study: activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin time (TT), reptilase time (RT), Russell's viper venom time (RVTT), fibrinogen, factor X and alpha-2 antiplasmin. RESULTS: Hemorrhagic manifestations were mild to moderate in nine patients, but severe and untractable in one. The most frequent clotting anomaly was defective fibrinogen conversion to fibrin, as demonstrated by prolongation of both TT (85% of cases) and RT (90% of cases). Low levels of factor X activity were observed in about 1 out of 4 samples, while fibrinogen and alpha2 antiplasmin levels were distributed over a wide range of values. PT was prolonged in 8 and aPTT in 25 patients. The search for lupus anticoagulant was negative in samples showing a prolongation of aPTT and/or RVVT. INTERPRETATION AND CONCLUSIONS: The prolongation of TT and RT is not dependent on either the presence of a heparin-like substance in the plasma or on fibrinogen levels; furthermore, the prolongation of RVVT is not related to factor X level. The hypothesized presence in the plasma of an inhibitor of fibrin formation could also affect factor X activation by Russell viper venom. The prolongation of TT and RT represents a peculiar feature of amyloidosis. The variability in the behavior of the other clotting times and hemostatic factors studied is mirrored in the heterogeneity of the clinical features observed in this disease.

Abnormalities in thrombin-antithrombin pathway in AL amyloidosis.

Various pathogenic factors have been proposed to explain the abnormal hemostasis observed in AL amyloidosis. Since imbalance between clotting factors and inhibitors could play a pathogenic role in both hemorrhagic and thrombotic manifestations, we investigated the thrombin-antithrombin pathway in 35 patients with AL amyloidosis. Ten patients suffered from bleeding while 3 patients experienced deep venous thrombosis. Thrombin time was prolonged in 29 subjects, the mean values of antithrombin III activity (ATIII Act) were significantly lower than those of antithrombin III antigen (ATIII Ag) with loss of relationship between these two different techniques of ATIII detection, normally observed in healthy controls. In 19 patients increased levels of thrombin-antithrombin (TAT) complexes were present. Crossed immunoelectrophoresis of ATIII, performed in presence of heparin, evidenced ATIII forms with reduced binding capacity to heparin and TAT complexes of various electrophoretic mobilities. In conclusion, the impairment of the thrombin-antithrombin pathway, in association with the low ATIII biological activity, might play a pathogenic role in the hypercoagulable state reported in AL amyloidosis, despite the higher frequency of bleeding manifestations.

The new apolipoprotein A-I variant leu(174) --> Ser causes hereditary cardiac amyloidosis, and the amyloid fibrils are constituted by the 93-residue N-terminal polypeptide.

We identified a novel missense mutation in the apolipoprotein A-I gene, T2069C Leu(174) --> Ser, in a patient affected by familial systemic nonneuropathic amyloidosis. The amyloid deposits mostly affected the heart of the proband, who underwent transplantation for end-stage congestive heart failure. Amyloid fibrils of myocardial and periumbilical fat samples immunoreacted exclusively with anti-ApoA-I antibodies. Amyloid fibrils extracted from the heart were constituted, according to amino acid sequencing and mass spectrometry analysis, by an amino-terminal polypeptide ending at Val(93) of apolipoprotein A-I (apoA-I); no other significant fragments were detected. The mutation segregates with the disease; it was demonstrated in the proband and in an affected uncle and excluded in three healthy siblings. The plasma levels of high-density lipoprotein and apoA-I were significantly lower in the patient than in unaffected individuals. This represents the first case of familial apoA-I amyloidosis in which the mutation is outside the polypeptide fragment deposited as fibrils. Visualization of the mutation in the three-dimensional structure of lipid-free apoA-I, composed of four identical polypeptide chains, indicates that position 174 of one chain is located near position 93 of an adjacent chain and suggests that the amino acid replacement in position 174 is permissive for a proteolytic split at the C-terminal of Val(93).

The degrees of plasma cell clonality and marrow infiltration adversely influence the prognosis of AL amyloidosis patients.

BACKGROUND AND OBJECTIVE: Primary amyloidosis is a lethal form of plasma cell (PC) dyscrasia characterized by deposits of monoclonal immunoglobulin light chains that cause organ dysfunction. In contrast to multiple myeloma, the amyloid clone is typically indolent and of small size, and marrow PC clonality is not always apparent. This is generally investigated by analyzing the light chain isotype ratio in bone marrow PC. We investigated whether the degree of PC infiltration (PC%) and clonality (PC isotype ratio) affected survival in 56 consecutive patients with primary amyloidosis. DESIGN AND METHODS: PC% was determined by morphologic examination. Immunofluorescence microscopy was used to determine the PC light chain isotype ratio. Statistical analysis was carried out using Cox regression models. RESULTS: The degrees of PC clonality and infiltration were inversely correlated with survival (PC isotype ratio, p = 0.001; PC%, p = 0.008). The two variables were weakly correlated (p = 0.02; r = 0.3). Bone marrow PC isotype ratio demonstrated a powerful independent prognostic value at multivariate analysis when analyzed together with congestive heart failure (the major known negative prognostic factor) and PC%. k/l ratio cut-off values of 0.2 (l patients, p = 0.022) and 16 (k patients, p = 0.03) discriminated two groups with a similar number of patients and significantly different survivals. INTERPRETATION AND CONCLUSIONS: PC clonality and marrow infiltration are important parameters that influence prognosis, presumably because they reflect the amount of pathogenic light chain synthesis.

Clonality and specificity of cryoglobulins associated with HCV: pathophysiological implications.

BACKGROUND/AIMS: Hepatitis C virus (HCV) infection plays a central role in the pathogenesis of mixed cryoglobulinemia through molecular mechanisms which remain to be elucidated. The aim of this study was to investigate the role of antibody responses to HCV in the pathogenesis of cryoglobulinemia through characterization of the anti-HCV specificity and immunochemical characteristics of the immunoglobulins involved in cryoprecipitation. METHODS: Sera from 50 consecutive patients with chronic HCV infection (RNA positive) were screened for the presence of cryoglobulins. The two major components of cryoprecipitates, IgM rheumatoid factors and IgG, were separated by high performance liquid chromatography and analyzed for immunochemical composition by immunoblotting and antibody specificity by ELISA and immunoblotting using recombinant HCV proteins and synthetic peptides as antigens. RESULTS: Cryoprecipitates were observed in 27 patients and characterized by immunofixation: 13 (48%) were classified as type II and 14 (52%) as type III. Monoclonal immunoglobulins were detected by immunoblotting in 20 cryoprecipitates: IgM in 14 samples and IgG in 14, with a clear preponderance of IgG3 (12/14). Specificity studies on sera and purified IgM and IgG fractions from cryoprecipitates revealed enrichment in cryoglobulins, predominantly polyclonal IgG1, reactive with the HCV structural proteins, whereas specificities for nonstructural viral proteins were relatively less represented compared to whole serum. No restricted pattern of fine specificity was observed. IgG3 subclass was apparently not involved in HCV nucleoprotein binding. CONCLUSIONS: Our findings do not support a direct link between monoclonal cryoglobulins and immune response to HCV According to the proposed pathogenetic model, HCV infection can induce the formation of cryoprecipitable rheumatoid factors, sustain their production, and eventually lead to monoclonal B-cell expansion through several cooperative mechanisms.

Immunochemical characterization of the cryoglobulins: pathophysiologic implications.

Immunochemical study of the cryoglobulins has produced a classification of three main types which present clinical correlates. With the current standard immunofixation technique the vast majority of cryoglobulins are presently classified as type II. High-resolution immunoelectrophoretic techniques (immunoblotting and two-dimensional polyacrylamide gel electrophoresis) have helped to identify new sub-types whose clinical relevance is as yet undetermined. Nevertheless, these sensitive techniques could contribute to elucidate the various stages in the natural history of HCV-related cryoglobulins, from possible earlier HCV-antigen-driven polyclonal B cell proliferation, to autonomous monoclonal benign, to malignant B cell proliferation.

[Disturbances of equilibrium in the aged]. / I disturbi dell'equilibrio nella terza età.

The occurrence during the last year of vestibular disorders, faints and drop attacks was investigated in 150 patients consecutively admitted to a geriatric hospital. The clinical features of these episodes were recorded by means of a proper questionnaire. True vertigo and/or feeling of unstable equilibrium were referred by 54,6% of the patients inquired into, whereas episodes interpretable as faints and drop attacks showed by far lower prevalences, respectively 13,3% and 6%. The Authors call attention to the difficulties in differential diagnosis among these three kinds of phenomena in the current practice.