Assessment of the Relationship Between Genetic Determinants of Thyroid Function and Atrial Fibrillation: A Mendelian Randomization Study.

Importance: Increased free thyroxine (FT4) and decreased thyrotropin are associated with increased risk of atrial fibrillation (AF) in observational studies, but direct involvement is unclear. Objective: To evaluate the potential direct involvement of thyroid traits on AF. Design, Setting, and Participants: Study-level mendelian randomization (MR) included 11 studies, and summary-level MR included 55 114 AF cases and 482 295 referents, all of European ancestry. Exposures: Genomewide significant variants were used as instruments for standardized FT4 and thyrotropin levels within the reference range, standardized triiodothyronine (FT3):FT4 ratio, hypothyroidism, standardized thyroid peroxidase antibody levels, and hyperthyroidism. Mendelian randomization used genetic risk scores in study-level analysis or individual single-nucleotide polymorphisms in 2-sample MR for the summary-level data. Main Outcomes and Measures: Prevalent and incident AF. Results: The study-level analysis included 7679 individuals with AF and 49 233 referents (mean age [standard error], 62 [3] years; 15 859 men [29.7%]). In study-level random-effects meta-analysis, the pooled hazard ratio of FT4 levels (nanograms per deciliter) for incident AF was 1.55 (95% CI, 1.09-2.20; P = .02; I2 = 76%) and the pooled odds ratio (OR) for prevalent AF was 2.80 (95% CI, 1.41-5.54; P = .003; I2 = 64%) in multivariable-adjusted analyses. The FT4 genetic risk score was associated with an increase in FT4 by 0.082 SD (standard error, 0.007; P < .001) but not with incident AF (risk ratio, 0.84; 95% CI, 0.62-1.14; P = .27) or prevalent AF (OR, 1.32; 95% CI, 0.64-2.73; P = .46). Similarly, in summary-level inverse-variance weighted random-effects MR, gene-based FT4 within the reference range was not associated with AF (OR, 1.01; 95% CI, 0.89-1.14; P = .88). However, gene-based increased FT3:FT4 ratio, increased thyrotropin within the reference range, and hypothyroidism were associated with AF with inverse-variance weighted random-effects OR of 1.33 (95% CI, 1.08-1.63; P = .006), 0.88 (95% CI, 0.84-0.92; P < .001), and 0.94 (95% CI, 0.90-0.99; P = .009), respectively, and robust to tests of horizontal pleiotropy. However, the subset of hypothyroidism single-nucleotide polymorphisms involved in autoimmunity and thyroid peroxidase antibodies levels were not associated with AF. Gene-based hyperthyroidism was associated with AF with MR-Egger OR of 1.31 (95% CI, 1.05-1.63; P = .02) with evidence of horizontal pleiotropy (P = .045). Conclusions and Relevance: Genetically increased FT3:FT4 ratio and hyperthyroidism, but not FT4 within the reference range, were associated with increased AF, and increased thyrotropin within the reference range and hypothyroidism were associated with decreased AF, supporting a pathway involving the pituitary-thyroid-cardiac axis.

Associations between normal range albuminuria, renal function and cardiovascular function in a population-based imaging study.

BACKGROUND AND AIMS: In patients with impaired renal function and macroalbuminuria, cardiovascular risk factors are highly prevalent, however, whether this is also present in the general population is unclear. We investigated whether normal-range albuminuria and renal function are associated with cardiovascular function in the general population. METHODS: In this cross-sectional analysis of the NEO study, urinary albumin-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and intima-media thickness were assessed in all participants (n = 6503), and a random subset underwent MRI for pulse wave velocity (n = 2451) and/or cardiac imaging (n = 1138). RESULTS: Multiple linear regression analysis was performed while adjusting for sex, age, smoking, mean arterial blood pressure, total body fat, and fasting glucose. After adjustment, albuminuria and renal function were positively associated with left ventricle (LV) mass index (UACR, 0.941 g/m2 [95% CI: 0.21,1.67] p = 0.012; eGFR, 0.748 g/m2 [95% CI: 0.15,1.35] p = 0.015) and LV cardiac index (UACR, 0.056 L/min/m2 [95% CI: 0.00,0.11] p = 0.038; eGFR, 0.080 L/min/m2 [95% CI: 0.03,0.13] p = 0.001). Albuminuria showed a weak association with arterial thickness (UACR, 0.003 mm [95% CI: 0.00,0.01] p = 0.015) and arterial stiffness (UACR, 0.073 m/s [95% CI: 0.01,0.13] p = 0.036), but not with renal function. No associations were observed for LV ejection fraction and LV diastolic function. CONCLUSIONS: Normal-range albuminuria was positively associated with LV mass index, LV cardiac index, arterial thickness and arterial stiffness. Our findings support the hypothesis that even within normal range, albuminuria is a marker of cardiovascular health.

Guide extension catheter stepwise advancement facilitated by repeated distal balloon anchoring.

Coronary stent delivery can be extremely challenging in tortuous and calcified lesions especially when radial approach is chosen. Guide extension catheter is a useful tool for overcoming the inherent difficulties arising by the use of radial access in complex percutaneous interventions. We describe a technique for guide extension catheter system advancement by presenting two cases. This was performed stepwise by repeated distal balloon anchoring in the coronary artery of interest.

Advantages and disadvantages of unstructured cardiovascular risk factor screening for follow-up in primary care.

BACKGROUND: In contrast to structured, integrated risk assessment in primary care, unstructured risk factor screening outside primary care and corresponding recommendations to consult a general practitioner (GP) are often based on one abnormal value of a single risk factor. This study investigates the advantages and disadvantages of unstructured screening of blood pressure and cholesterol outside primary care. METHODS: After the baseline visit of the Netherlands Epidemiology of Obesity study (population-based prospective cohort study in persons aged 45-65 years, recruited 2008-2012) all participants received a letter with results of blood pressure and cholesterol, and a recommendation to consult a GP if results were abnormal. Four years after the start of the study, participants received a questionnaire about the follow-up of their results. RESULTS: The study population consisted of 6343 participants, 48% men, mean age 56 years, mean body mass index 30 kg/m(2). Of all participants 66% had an abnormal result and, of these, 49% had a treatment indication based on the risk estimation system SCORE-NL 2006. Of the 25% of the participants who did not consult a GP, 40% had a treatment indication. Of the participants with an abnormal result 19% were worried, of whom 60% had no treatment indication. CONCLUSIONS: In this population 51% of the participants with an abnormal result had unnecessarily received a recommendation to consult a GP, and 10% were unnecessarily worried. GPs should be informed about the complete risk assessment, and only participants at intermediate or high risk should receive a recommendation to consult a GP.

Overweight can be used as a tool to guide case-finding for cardiovascular risk assessment.

BACKGROUND: In general practice, it is too time-consuming to invite all patients for cardiovascular risk assessment. OBJECTIVE: To examine how many patients with an indication for treatment with cardiovascular medication can be identified by ad hoc case-finding when all patients with overweight/obesity are invited for risk assessment. METHODS: A cross-sectional analysis of the baseline measurements of the Netherlands Epidemiology of Obesity study, a population-based prospective cohort study in 6673 persons aged 45-65 years. We calculated the proportion of participants with a treatment indication using the risk prediction Systematic COronary Risk Evaluation (SCORE-NL 2011), for lean, overweight and obese participants. Participants with a history of cardiovascular disease, diabetes mellitus or rheumatoid arthritis or using cardiovascular medication were not eligible for ad hoc case-finding because they were already identified as being at risk and/or had been treated. RESULTS: Of the study population, 30% had already been identified and/or treated with cardiovascular medication and were therefore not eligible for ad hoc case-finding. Of the eligible participants, 47% were lean, 41% overweight and 12% obese. Of the participants with overweight, 12% had a treatment indication and of the participants with obesity, 19% had a treatment indication. Of all participants with a treatment indication 24% were not yet treated. Of all participants with a new treatment indication, 70% had overweight or obesity. CONCLUSIONS: Of the participants with a treatment indication, 24% were not yet treated. Inviting patients with overweight/obesity for cardiovascular risk assessment may help to detect 70% of these residual patients with a treatment indication.

Echocardiographical determinants of an abnormal spatial QRS-T angle in chronic dialysis patients.

BACKGROUND: The spatial QRS-T angle describes the relation between ventricular depolarization and repolarization. Having a wide (abnormal) angle is considered an important predictor of arrhythmic events. Given the high incidence of sudden cardiac death in dialysis patients, this parameter is of particular interest in this patient group. The objective of this study was to assess the association of (modifiable) echocardiographic parameters and an abnormal spatial QRS-T angle in dialysis patients. METHODS: A total of 94 consecutive dialysis patients were included. In all patients a 12-lead electrocardiogram (ECG), a two-dimensional echocardiogram and routine blood samples were obtained. The spatial QRS-T angle was then calculated from the 12-lead ECG. An abnormal spatial QRS-T angle was defined as ≥130° in males and ≥116° in females. RESULTS: An abnormal spatial QRS-T angle was present in 27 (29%) patients. Patients with an abnormal spatial angle had a lower left ventricular ejection fraction (LVEF) of 47 ± 7 versus 55 ± 6% (P < 0.001) and had a higher left ventricular (LV) dyssynchrony, with a septal to lateral (S-L) delay of peak systolic velocity of 70 inter quartile range (iIQR) (40, 100) ms versus 30 IQR (10, 70) ms (P = 0.001), respectively. Multivariate logistic regression analysis controlling for possible confounders demonstrated that LVEF [odds ratio (OR) 0.82; 95% confidence interval (CI) 0.72-0.93, P = 0.001] and LV dyssynchrony (OR 1.19 per 10 ms; 95% CI 1.03-1.38, P = 0.02) were independent determinants of an abnormal spatial QRS-T angle in this patient group. CONCLUSIONS: LVEF and dyssynchrony are echocardiographic determinants of an abnormal spatial QRS-T angle in dialysis patients and might therefore represent a potential target for the prevention of sudden cardiac death in these patients.