Management of surgery in persons with hemophilia A receiving emicizumab prophylaxis: data from a national hemophilia treatment center

Background

Persons with hemophilia A may require surgical procedures. Real-world data on invasive procedures in persons with hemophilia A receiving emicizumab prophylaxis are limited.

Objectives

To evaluate the safety of invasive procedures in persons with hemophilia A receiving emicizumab prophylaxis and their outcomes in a longitudinally followed cohort.

Methods

Data from medical records of persons with hemophilia A with and without factor VIII (FVIII) inhibitors longitudinally followed at our tertiary center, who received emicizumab prophylaxis and underwent all types of invasive procedures, were retrieved. Outcomes of interest were bleeding and thrombotic complications.

Results

Overall, 35 patients underwent 56 invasive procedures, 18 (32.1%) were major. The median age was 36.3 years (IQR, 8.8-55.9 years); 12 patients (34.3%) were younger than 18 years at the time of procedure; 17 (48.6%) were patients with FVIII inhibitors. Among major procedures, orthopedic surgeries prevailed. All patients who underwent major procedures received factor replacement with either recombinant activated factor VII (patients with inhibitors) or FVIII (patients without inhibitors). Factor concentrates were administered prior to 32 (84.2%) of the minor procedures. Repeated doses were given according to international expert opinion recommendations and patients' condition.There were 7 bleeding events in 6 patients, 5 were major bleeds, including 1 patient who underwent a minor procedure without factor replacement. None of the patients experienced a thrombotic complication.

Conclusion

Invasive procedures can be performed safely in patients receiving emicizumab prophylaxis with close surveillance after surgery. Factor concentrates may be advised in selected patients undergoing minor procedures.

Four Decades of Carrier Detection and Prenatal Diagnosis in Hemophilia A: Historical Overview, State of the Art and Future Directions

Hemophilia A (HA), a rare recessive X-linked bleeding disorder, is caused by either deficiency or dysfunction of coagulation factor VIII (FVIII) resulting from deleterious mutations in the F8 gene encoding FVIII. Over the last 4 decades, the methods aimed at determining the HA carrier status in female relatives of HA patients have evolved from phenotypic studies based on coagulation tests providing merely probabilistic results, via genetic linkage studies based on polymorphic markers providing more accurate results, to next generation sequencing studies enabling highly precise identification of the causative F8 mutation. In parallel, the options for prenatal diagnosis of HA have progressed from examination of FVIII levels in fetal blood samples at weeks 20-22 of pregnancy to genetic analysis of fetal DNA extracted from chorionic villus tissue at weeks 11-14 of pregnancy. In some countries, in vitro fertilization (IVF) combined with preimplantation genetic diagnosis (PGD) has gradually become the procedure of choice for HA carriers who wish to prevent further transmission of HA without the need to undergo termination of pregnancies diagnosed with affected fetuses. In rare cases, genetic analysis of a HA carrier might be complicated by skewed X chromosome inactivation (XCI) of her non-hemophilic X chromosome, thus leading to the phenotypic manifestation of moderate to severe HA. Such skewed XCI may be associated with deleterious mutations in X-linked genes located on the non-hemophilic X chromosome, which should be considered in the process of genetic counseling and PGD planning for the symptomatic HA carrier. Therefore, whole exome sequencing, combined with X-chromosome targeted bioinformatic analysis, is highly recommended for symptomatic HA carriers diagnosed with skewed XCI in order to identify additional deleterious mutations potentially involved in XCI skewing. Identification of such mutations, which may profoundly impact the reproductive choices of HA carriers with skewed XCI, is extremely important.

Efficacy and safety of damoctocog alfa pegol prophylaxis in patients ⩾40 years with severe haemophilia A and comorbidities: post hoc analysis from the PROTECT VIII study

Background

Advances in treatment have enabled patients with haemophilia A to live longer and therefore may be subjected to comorbidities associated with ageing, in addition to disease-associated morbidities. There have been few reports to date on efficacy and safety of treatment specifically in patients with severe haemophilia A and comorbidities.

Objective

To explore the efficacy and safety of damoctocog alfa pegol prophylaxis in patients with severe haemophilia A aged ⩾40 years with comorbidities of interest.

Design

A post hoc analysis of data from the phase 2/3 PROTECT VIII study and its extension.

Methods

Bleeding and safety outcomes were analysed in a subgroup of patients aged ⩾40 years with ⩾1 comorbidity receiving damoctocog alfa pegol (BAY 94-9027; Jivi^®) prophylaxis.

Results

Thirty-four patients with severe haemophilia A were included in this analysis, with a mean age of 49.4 years at time of enrolment. The most prevalent comorbidities were hepatitis C (n = 33; chronic, n = 23), hepatitis B (n = 8) and hypertension (n = 11). Four patients had human immunodeficiency virus. All received damoctocog alfa pegol prophylaxis for the entire study [median (range) time in study = 3.9 (1.0-6.9) years]. During the main study and extension, median total annualised bleeding rates (ABRs) (Q1; Q3) were 2.1 (0.0; 5.8) and 2.2 (0.6; 6.0), respectively; median joint ABRs were 1.9 (0.0; 4.4) and 1.6 (0.0; 4.0), respectively. Mean adherence with prophylaxis schedule was greater than 95% throughout the study. No deaths or thrombotic events were reported.

Conclusion

Efficacy, safety and adherence of damoctocog alfa pegol were confirmed in patients aged ⩾40 years with haemophilia A and one or more comorbidities, with data for up to 7 years supporting its use as a long-term treatment option in this group.

Plain language summary

Advances in treatment mean that people with haemophilia A are now living longer and, as a result, may have additional medical conditions that occur with ageing. We aimed to investigate the efficacy and safety of the long-acting replacement factor VIII damoctocog alfa pegol in people with severe haemophilia A who had additional medical conditions. To do this, we investigated the recorded information about patients aged 40 years of age or older who had been treated with damoctocog alfa pegol in a previously completed clinical trial. We found that the treatment was well-tolerated; no deaths or thrombotic events (undesirable clotting events) were reported. Treatment was efficacious in reducing bleeding in this group of patients. The findings support the use of damoctocog alfa pegol as a long-term treatment for older patients with haemophilia A and coexisting conditions.

Women with Hemophilia: Case Series of Reproductive Choices and Review of Literature

Aim  Very little is known regarding reproductive choices, pregnancy, and delivery of women with moderate to severe hemophilia. Our aim was to describe our experience with three hemophiliac women and their journey to achieve motherhood.

Methods  Medical charts of women with moderate to severe hemophilia A treated at our center were evaluated. Data regarding choices of conception, pregnancy course, mode of delivery, and pregnancy outcomes were obtained.

Results  Three women are presented. Whereas patient 1 chose to adopt her first child and later had twins through egg donations and a surrogate mother, patient 2 underwent spontaneous pregnancy and delivered via cesarean section. Patient 3 preferred in vitro fertilization and preimplantation genetic diagnosis to avoid hemophilia and hemophilia carriership in her offspring.

Conclusion  The appropriate means to achieve parenthood for women with moderate to severe hemophilia should be individualized and requires support of a comprehensive multidisciplinary team.

Confirmed long-term safety and efficacy of prophylactic treatment with BAY 94-9027 in severe haemophilia A: final results of the PROTECT VIII extension study

Introduction

The phase 2/3 PROTECT VIII main study demonstrated efficacy and safety of BAY 94–9027 (damoctocog alfa pegol; Jivi^®), a B‐domain‐deleted recombinant factor VIII (FVIII), site‐specifically PEGylated to extend its half‐life.

Aim

To report the final efficacy and safety data for BAY 94–9027 from the PROTECT VIII extension.

Methods

Previously treated males aged 12–65 years with severe haemophilia A (FVIII <1%) who completed the multicentre, open‐label PROTECT VIII main study were eligible for the extension. Patients received either on demand or prophylaxis treatments (30‒40 IU/kg twice weekly [2 × W], 45‒60 IU/kg every 5 days [E5D], or 60 IU/kg every 7 days [E7D]) and could switch to any prophylaxis regimen (variable frequency) as needed. Annualised bleeding rates (ABR), zero bleeds and safety outcomes were included in this final analysis.

Results

At extension completion, patients (n = 121) received BAY 94–9027 for a median (range) total time of 3.9 (0.8–7.0) years. Median (Q1; Q3) total ABR was 1.49 (0.36; 4.80) for prophylaxis patients (n = 107), compared with 34.09 (20.3; 36.6) for on‐demand patients (n = 14). Median total ABRs for 2 × W (n = 23), E5D (n = 33), E7D (n = 23) and variable frequency (n = 28) groups were 1.57, 1.17, 0.65 and 3.10, respectively. Of prophylaxis patients, 20.6% were bleed‐free during the entire extension (median time, 3.2 years) and 50.0% were bleed‐free during the last 6 months. No patient developed FVIII inhibitors. No deaths or thrombotic events were reported.

Conclusions

Efficacy and safety of BAY 94–9027 was confirmed, with extension data supporting its use as a long‐term treatment option for patients with haemophilia A.

Comparing Physician and Patient Perspectives on Prophylactic Treatment with BAY 94-9027 for Severe Haemophilia A: A Post Hoc Analysis

Introduction

BAY 94-9027 is a newly developed extended half-life product to treat haemophilia, allowing for fewer injections than with standard products. This post hoc analysis aimed to compare physicians’ and patients’ opinions on BAY 94-9027 prophylaxis, and explore how qualitative interview data is aligned with the data from the Haemophilia-specific Quality of Life questionnaire for Adults (Haemo-QoL-A).

Methods

Exploratory qualitative interviews were conducted with physicians and patients by phone upon the exit of patients from the PROTECT VIII extension phase following a semi-directed guide. In this post hoc analysis, all transcripts were reviewed and reported concepts were compared to assess the level of concordance between physicians and patients. These qualitative data were compared with the Haemo-QoL-A mean global and subscale scores at baseline and end of main phase (36 weeks later).

Results

Ten physicians and 16 patients (mean age 47 years) from Israel, the Netherlands and the USA were interviewed. Significant improvements were reported by all physicians from baseline [e.g. lower frequency of bleeds (80%), improvement in emotional functioning (90%)], which is in concordance with patients’ reports. The improved confidence reported by physicians cascaded to greater participation in various activities, resulting in a better perceived emotional state and a significant improvement on the Haemo-QoL-A emotional impact subscale score (p = 0.04) between baseline and end of main phase. Most physicians (80%) reported improvement in bleed frequency, as patients did (88%). Improvement in physical functioning or mobility was not consistently reported in this 8-month study.

Conclusion

Interviewed physicians and patients generally agreed on the beneficial impact of BAY 94-9027, specifically regarding the increased level of self-confidence in patients and its subsequent positive impact on patients’ lives. These findings supported the observed improvement on the Haemo-QoL-A emotional impact subscale. Overall, this study highlights the concordance between physician and patient perspective on the positive experience with BAY 94-9027.

BAY 81-8973 demonstrated efficacy, safety and joint status improvement in patients with severe haemophilia A in the LEOPOLD I extension for ≤2 years

OBJECTIVES

BAY 81-8973 (Kovaltry^® ), a full-length, unmodified, recombinant human factor VIII, provided excellent bleeding control for patients with haemophilia A in the pivotal 1-year LEOPOLD I trial. The LEOPOLD I extension evaluated long-term efficacy and safety of BAY 81-8973 prophylaxis.

METHODS

After completing LEOPOLD I, patients continued receiving 20-50 IU/kg BAY 81-8973 two- or three-times weekly in the extension. Outcomes included annualised bleeding rate (ABR) and haemostasis during surgery.

RESULTS

Fifty-five patients aged 12-65 years participated in the extension. Median (range) exposure days during the 2-year total study period was 309 (115-355). No patient switched regimens. Median (Q1; Q3) ABR for all bleeds was 2.0 (1.0; 6.1) during the pivotal study, 2.0 (0.0; 5.2) during the extension, and 2.0 (0.5; 5.5) combined. The proportion of joint bleeds affecting target joints decreased (pivotal study: 90.9%, extension: 60.0%). Haemostasis was assessed as excellent/good in all five major surgeries. One serious adverse event (myocardial infarction) occurred in a patient with cardiovascular risk factors. No patients developed inhibitors.

CONCLUSIONS

BAY 81-8973 prophylaxis efficacy outcomes in the pivotal study were maintained or, in the case of joint protection, improved during the extension, with a safety and tolerability profile consistent with previous experience.

BAY 94-9027 prophylaxis is efficacious and well tolerated for up to >5 years with extended dosing intervals: PROTECT VIII extension interim results

Introduction

BAY 94‐9027 is an extended‒half‐life, site‐specifically PEGylated, B‐domain‒deleted recombinant factor VIII (FVIII). The PROTECT VIII main study demonstrated efficacy of bleed control using extended‐interval prophylaxis with BAY 94‐9027 for 36 weeks.

Aim

To report long‐term efficacy and safety of prophylaxis with BAY 94‐9027 in a descriptive analysis of the ongoing PROTECT VIII extension with a total treatment time of up to >5 years.

Methods

Previously treated males aged 12‐65 years with severe haemophilia A who completed the PROTECT VIII main study were eligible for the open‐label extension. Patients received on‐demand treatment or prophylaxis (30‒40 IU/kg twice weekly, 45‒60 IU/kg every 5 days, or 60 IU/kg every 7 days) and could switch regimens as needed.

Results

Patients (N = 121; on demand, n = 14; prophylaxis, n = 107) accumulated a median (range) of 3.9 years (297‒1965 days) and 223 (23‒563) total exposure days by 31 January 2018. During the extension, median (quartile [Q]1; Q3) annualized bleeding rates (ABRs) for total bleeds were 1.6 (0.3; 4.6) for patients receiving prophylaxis and 34.1 (20.3; 36.6) for patients receiving on‐demand treatment. ABRs for twice‐weekly (n = 23), every‐5‐days (n = 33), every‐7‐days (n = 23) and variable frequency (n = 28) treatments were 1.7, 1.2, 0.7 and 3.1, respectively. Of prophylaxis patients, 20.6% were bleed‐free throughout the extension (median time, 3.2 years), and 51.0% were bleed‐free during the last 6 months. No patients developed FVIII inhibitors.

Conclusions

BAY 94‐9027 prophylaxis was efficacious and well tolerated with dosing intervals up to every 7 days for a median (range) of 3.9 years (0.8‐5.4 years).

Efficacy and safety of BAY 81-8973, a full-length recombinant factor VIII: results from the LEOPOLD I trial

INTRODUCTION

BAY 81-8973 (Kovaltry(®) ) is a full-length, unmodified recombinant human factor VIII (FVIII) with the same amino acid sequence as sucrose-formulated recombinant FVIII and is produced using additional advanced manufacturing technologies.

AIM

To demonstrate efficacy and safety of BAY 81-8973 for treatment of bleeds and as prophylaxis based on two different potency assignments.

METHODS

In LEOPOLD I (ClinicalTrials.gov identifier, NCT01029340), males aged 12-65 years with severe haemophilia A and ≥150 exposure days received BAY 81-8973 20-50 IU kg(-1) two or three times per week for 12 months. Potency was based on chromogenic substrate assay per European Pharmacopoeia and label adjusted to mimic one-stage assay potency. Patients were randomized for potency sequence and crossed over potency groups after 6 months, followed by an optional 12-month extension. Primary efficacy endpoint was annualized bleeding rate (ABR). Patients also received BAY 81-8973 during major surgeries.

RESULTS

Sixty-two patients received BAY 81-8973 prophylaxis and were included in the analysis. Median ABR was 1.0 (quartile 1, 0; quartile 3, 5.1) without clinically relevant differences between potency periods. Median ABR was similar for twice-weekly vs. three times-weekly dosing (1.0 vs. 2.0). Haemostasis was maintained during 12 major surgeries. Treatment-related adverse event (AE) incidence was ≤7% overall; no patient developed inhibitors. One patient with risk factors for cardiovascular disease developed a myocardial infarction.

CONCLUSIONS

BAY 81-8973 was efficacious in preventing and treating bleeding episodes, irrespective of the potency assignment method, with few treatment-related AEs. Caution should be used when treating older patients with cardiovascular risk factors.

Giant intracardiac blood cyst: assessing the relationship between its formation and previous cardiac surgery

This case report discusses a 23-year-old male patient who presented with shortness of breath during exercise. Echocardiography revealed an intracardiac mass located on the mitral valve. His medical history included surgical closure of an atrial septal defect type 2 at the age of 2 years. After being discussed within a multidisciplinary heart team, the intracardiac mass was surgically removed. Histopathological examination revealed a blood cyst. This case report emphasises that the presence of an acquired intracardiac cyst is a rare entity and that a pathophysiological association between the formation of a blood cyst and previous cardiac surgery has not been proven yet.

Correlation between endogenous VWF:Ag and PK parameters and bleeding frequency in severe haemophilia A subjects during three-times-weekly prophylaxis with rFVIII-FS

Patients with severe haemophilia A experience frequent and spontaneous bleeding, causing debilitating damage to joints and decreasing quality of life. Prophylaxis with factor VIII (FVIII) reduces joint damage if initiated early. Circulating FVIII levels may be influenced by endogenous von Willebrand factor (VWF), a chaperone protein that binds and stabilizes FVIII. The aim of this study was to determine whether endogenous VWF antigen (VWF:Ag) levels are correlated with FVIII pharmacokinetic (PK) parameters and clinical outcomes in patients with severe haemophilia A. Previously treated, non-inhibitor patients in a multinational, randomized, double-blind, Ph II study received prophylaxis with once-weekly BAY 79-4980 (35 IU kg⁻¹) or thrice-weekly recombinant sucrose-formulated FVIII (rFVIII-FS; 25 IU kg⁻¹). PK parameters were evaluated at weeks 1 and 26. The number of bleeds per patient during the study was captured as part of the core efficacy endpoint. Spearman rank correlations assessed relationships of VWF:Ag levels with patient age, PK and annualized bleeding rate. Of 131 study patients (aged 13−64 years; BAY 79-4980, n = 63; rFVIII-FS, n = 68), 27 (21%; n = 15 and 12 respectively) were evaluable for PK assessment. Baseline VWF:Ag levels correlated with patient age (P < 0.0001). There was no significant difference in PK results between treatments; thus, PK parameters and VWF levels of all patients were analysed together. AUC_norm and T_1/2 significantly increased with increased VWF:Ag (P < 0.001); clearance significantly decreased with increased VWF:Ag (P = 0.002). Annualized bleeding rate in patients treated with 3× per week rFVIII-FS significantly correlated with VWF:Ag and age (P = 0.038 and 0.021 respectively). PK parameters as well as the clinical outcome significantly correlated with endogenous VWF:Ag. The improved clinical outcome in subjects with high VWF:Ag levels may be explained by VWF:Ag influence on FVIII PK.

Trp207Gly in platelet glycoprotein Ibalpha is a novel mutation that disrupts the connection between the leucine-rich repeat domain and the disulfide loop structure and causes Bernard-Soulier syndrome

BACKGROUND

Bernard-Soulier syndrome (BSS) is a severe inherited bleeding disorder that is caused by a defect in glycoprotein (GP)Ib-IX-V complex, the platelet membrane receptor for von Willebrand factor.

PATIENTS

The diagnosis of BSS was made in two members of a Bukharian Jewish family who had life-long thrombocytopenia associated with mucocutaneous bleeding manifestations.

METHODS AND RESULTS

Flow cytometry and Western blot analyses showed only trace amounts of GPIb and GPIX on the patients' platelets. Sequence analysis of the GPIbalpha gene revealed a homozygous T > G transversion at nucleotide 709 predicting Trp207Gly substitution in the mature protein. Introduction of the mutation into a mammalian expression construct abolished the surface expression of GPIbalpha in transfected baby hamster kidney cells. The crystal structure of the N-terminus of GPIbalpha (PDB: 1SQ0) indicates that Trp207 is completely buried and located in a disulfide loop structure that interacts with the leucine-rich repeat (LRR) domain.

CONCLUSION

A novel mutation, Trp207Gly, causes BSS and predicts disruption of the interaction between a disulfide loop and the LRR domain that is essential for the integrity of GPIbalpha structure.

Hepatitis C at the Israeli National Hemophilia Center

Haemophilia patients who received non-virucidally treated large pool clotting factors before 1987 have a high rate of chronic hepatitis C viral infection (HCV). Some patients are coinfected with HIV. Haemophilia patients and other coagulation disorders were treated at one centre since the beginning of the 1970, and the Israeli National Hemophilia Center (INHC) was officially founded in 1987. To characterize patients with HCV as well as patients with HCV/HIV coinfection at the INHC. Patients with haemophilia and other coagulation disorders positive for HCV antibodies were evaluated between 2001 and 2004. Demographic data, type and severity of coagulation disorder, frequency of coagulation factor usage and treatment with concentrated clotting factors prior to 1987 were recorded. Liver enzymes, viral load, genotype and data supporting advanced liver disease were evaluated. About 179 of 239 haemophilia patients (75%) tested positive for anti-HCV antibodies. Our cohort consisted of 165 patients in whom clinical, biochemical and virological data were available. About 117 patients had active HCV infection with HCV-RNA-positive, and 27 were HCV/HIV coinfected. Twenty-one patients (13%) persistently tested HCV-RNA-negative, hence were considered to clear their HCV infection. There was no former USSR immigrants among HCV/HIV coinfected compared with HCV-infected or HCV-RNA-negative groups (0 vs. 30% and 38%, respectively; P < 0.001). HCV-RNA-negative patients used concentrated coagulation factor less frequently than HCV or HCV/HIV-infected patients (48% vs. 73%; P = 0.023, and 48% vs. 74%; P = 0.043, respectively). The use of concentrated clotting factors before 1987 was significantly more frequent in HCV/HIV than in either HCV-infected or HCV-RNA-negative patients (96% vs. 49% and 48%, respectively; P < 0.001). Compared with HCV/HIV subjects, patients with HCV monoinfection were characterized by a higher proportion of infection with genotype 1 (80% vs. 61%; P = 0.027). The rate of persistently normal liver enzymes in these patients was higher (24% vs. 7%; P = 0.05) than in the HCV/HIV-coinfected patients. Advanced liver disease was significantly more common in patients with HCV/HIV-coinfection than in HCV-monoinfected patients (11% vs. 3%; P = 0.045). The majority of haemophilia patients are infected with HCV. Viral clearance occurred in a minority of these patients. HCV monoinfected and HCV/HIV coinfected differ clinically and prognostically.

Allele-specific replication associated with aneuploidy in blood cells of patients with hematologic malignancies

We hypothesize that coordination between the two DNA parental sets in somatic cells is essential for the stability of the diploid genome, and that its disruption is associated with the many alterations observed in the various cancerous phenotypes. As coordination between two allelic counterparts is well exemplified by synchrony in replication timing, we examined, in blood cells of patients suffering from various hematologic malignancies, replication patterns of five loci. These loci were three cancer-implicated genes (TP53, AML1, and RB1) and two nontranscribed sequences engaged in chromosome segregation. All five loci normally display synchrony in allelic replication timing. In addition, in order to exemplify an asynchronous mode of allelic replication, we followed the replication of allelic counterparts of an imprinted gene (SNRPN), which is distinguished by its asynchronous mode of allelic replication (allele-specific replication). Allelic replication patterns were studied by fluorescence in situ hybridization (FISH), which has been shown to distinguish between nonreplicated and replicated regions of the genome in interphase cells, based on the structure of the specific hybridization signals that are being detected. Using the FISH replication assay we observed, for all loci which normally exhibit synchrony in allelic replication, loss of synchrony when present in blood cells of patients with hematologic malignancies. The loss of synchrony in allelic replication in patients' cells was accompanied by aneuploidy (chromosome losses and gains), the hallmark of cancer. We were able to reinstate the normal pattern of replication in the patients' cells by introducing an inhibitor of DNA methylation. It thus appears loss of allelic coordination is an epigenetic alteration characterizing cancer, which is easily identified by simple cytogenetic means and has a potential use in both cancer investigation and detection.

Sympathovagal imbalance in hyperthyroidism

We assessed sympathovagal balance in thyrotoxicosis. Fourteen patients with Graves' hyperthyroidism were studied before and after 7 days of treatment with propranolol (40 mg 3 times a day) and in the euthyroid state. Data were compared with those obtained in a group of age-, sex-, and weight-matched controls. Autonomic inputs to the heart were assessed by power spectral analysis of heart rate variability. Systemic exposure to sympathetic neurohormones was estimated on the basis of 24-h urinary catecholamine excretion. The spectral power in the high-frequency domain was considerably reduced in hyperthyroid patients, indicating diminished vagal inputs to the heart. Increased heart rate and mid-frequency/high-frequency power ratio in the presence of reduced total spectral power and increased urinary catecholamine excretion strongly suggest enhanced sympathetic inputs in thyrotoxicosis. All abnormal features of autonomic balance were completely restored to normal in the euthyroid state. beta-Adrenoceptor antagonism reduced heart rate in hyperthyroid patients but did not significantly affect heart rate variability or catecholamine excretion. This is in keeping with the concept of a joint disruption of sympathetic and vagal inputs to the heart underlying changes in heart rate variability. Thus thyrotoxicosis is characterized by profound sympathovagal imbalance, brought about by increased sympathetic activity in the presence of diminished vagal tone.

Endothelial function in patients with hyperthyroidism before and after treatment with propranolol and thiamazol

Hyperthyroidism is associated with a higher incidence of arterial thromboembolism; increasing age, atrial fibrillation, and mitral valve abnormalities are risk factors. However, the contribution of endogenous coagulation parameters is unclear. Because thyroid hormone influences receptor and transcription factors, it can be expected that it will influence proteins involved in coagulation processes synthetised in many cells. Fourteen hyperthyroid patients were studied untreated, after 1 week of treatment with propranolol, and after therapeutic treatment with thiamazol. Fourteen matched controls were used for comparison. On each occasion, endothelial marker proteins, coagulation/fibrinolysis factors, and inflammatory (liver) markers were measured. Excess thyroid hormone was associated with elevated levels of most endothelium-associated proteins. In addition, plasma fibronectin and fibrinogen were increased, while plasminogen was decreased. No evidence was found that hyperthyroidism was associated with coagulation/fibrinolysis activation, or with increased levels of the inflammation markers interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) or C-reactive protein (CRP). Propranolol treatment only lowered the von Willebrand factor propeptide, and slightly increased plasminogen. Treatment with thiamazol returned all parameters to normal. Hyperthyroidism increased the plasma levels of most endothelial marker proteins, and of some liver-synthetized proteins. No evidence for coagulation/fibrinolysis activation was found. However, it appears that endothelial activation, which is indicative of a procoagulant state, is present in hyperthyroidism. This may explain the association between hyperthyroidism and thromboembolism especially if other risk factors are present. von Willebrand factor II (vWF:Ag-II) levels may be suitable markers to evaluate acute changes in endothelial function because this parameter responds more rapidly to changes in endothelial function than other factors.

Methylenetetrahydrofolate reductase genotypes and early-onset coronary artery disease

BACKGROUND

Homozygosity for the common (677C-->T) mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with hyperhomocysteinemia, but there is uncertainty as to the association between this mutation and coronary artery disease (CAD). This study examined the association between MTHFR genotypes and age at onset of CAD.

METHODS AND RESULTS

Patients (n=169) with documented myocardial infarction or angiographically documented CAD who were aged < or = 55 years at onset of CAD symptoms and DNA samples from control subjects (n=313) were studied. The prevalence of homozygosity among patients with early CAD onset (aged < or = 45 years) was 28%, which was significantly higher than that in patients with later onset (13%) and in control subjects (14%) (odds ratio 2.4, 95% CI 1.24 to 4.69, P=0.006, and odds ratio 2.7, 95% CI 1.15 to 6.42, P=0.01, respectively). Plasma folate was lower in TT homozygotes who had early CAD onset than in those with later onset (P=0.005). Among patients with plasma folate in the lowest quintile (< or = 12.6 nmol/L), 31% were homozygotes, as were 45% of those with low plasma folate and early CAD onset. There was no difference in the prevalence of traditional risk factors among genotypes. The frequency of homozygosity in patients with < or = 1 risk factor was higher than in those with > or = 2 risk factors (30% versus 12%, P<0.05). In multiple regression analysis, TT homozygosity and plasma folate were independently associated with CAD, but the impact of folate was small.

CONCLUSIONS

Homozygosity for the 677C-->T mutation of MTHFR is common and is associated with an increased risk of premature CAD in this population.