Thibault Petit

Inactive Matrix Gla Protein Is Causally Related to Adverse Health Outcomes: A Mendelian Randomization Study in a Flemish Population

Matrix Gla-protein is a vitamin K–dependent protein that strongly inhibits arterial calcification. Vitamin K deficiency leads to production of inactive nonphosphorylated and uncarboxylated matrix Gla protein (dp–ucMGP). The risk associated with dp–ucMGP in the population is unknown. In a Flemish population study, we measured circulating dp–ucMGP at baseline (1996–2011), genotyped MGP, recorded adverse health outcomes until December 31, 2012, and assessed the multivariable-adjusted associations of adverse health outcomes with dp–ucMGP. We applied a Mendelian randomization analysis using MGP genotypes as instrumental variables. Among 2318 participants, baseline dp–ucMGP averaged 3.61 &mgr;g/L. Over 14.1 years (median), 197 deaths occurred, 58 from cancer and 70 from cardiovascular disease; 85 participants experienced a coronary event. The risk of death and non-cancer mortality curvilinearly increased (P⩽0.008) by 15.0% (95% confidence interval, 6.9–25.3) and by 21.5% (11.1–32.9) for a doubling of the nadir (1.43 and 0.97 &mgr;g/L, respectively). With higher dp–ucMGP, cardiovascular mortality log-linearly increased (hazard ratio for dp–ucMGP doubling, 1.14 [1.01–1.28]; P=0.027), but coronary events log-linearly decreased (0.93 [0.88–0.99]; P=0.021). dp–ucMGP levels were associated (P⩽0.001) with MGP variants rs2098435, rs4236, and rs2430692. For non-cancer mortality and coronary events (P⩽0.022), but not for total and cardiovascular mortality (P≥0.13), the Mendelian randomization analysis suggested causality. Higher dp–ucMGP predicts total, non-cancer and cardiovascular mortality, but lower coronary risk. For non-cancer mortality and coronary events, these associations are likely causal.Matrix Gla-protein is a vitamin K–dependent protein that strongly inhibits arterial calcification. Vitamin K deficiency leads to production of inactive nonphosphorylated and uncarboxylated matrix Gla protein (dp–ucMGP). The risk associated with dp–ucMGP in the population is unknown. In a Flemish population study, we measured circulating dp–ucMGP at baseline (1996–2011), genotyped MGP , recorded adverse health outcomes until December 31, 2012, and assessed the multivariable-adjusted associations of adverse health outcomes with dp–ucMGP. We applied a Mendelian randomization analysis using MGP genotypes as instrumental variables. Among 2318 participants, baseline dp–ucMGP averaged 3.61 μg/L. Over 14.1 years (median), 197 deaths occurred, 58 from cancer and 70 from cardiovascular disease; 85 participants experienced a coronary event. The risk of death and non-cancer mortality curvilinearly increased ( P ≤0.008) by 15.0% (95% confidence interval, 6.9–25.3) and by 21.5% (11.1–32.9) for a doubling of the nadir (1.43 and 0.97 μg/L, respectively). With higher dp–ucMGP, cardiovascular mortality log-linearly increased (hazard ratio for dp–ucMGP doubling, 1.14 [1.01–1.28]; P =0.027), but coronary events log-linearly decreased (0.93 [0.88–0.99]; P =0.021). dp–ucMGP levels were associated ( P ≤0.001) with MGP variants rs2098435 , rs4236 , and rs2430692. For non-cancer mortality and coronary events ( P ≤0.022), but not for total and cardiovascular mortality ( P ≥0.13), the Mendelian randomization analysis suggested causality. Higher dp–ucMGP predicts total, non-cancer and cardiovascular mortality, but lower coronary risk. For non-cancer mortality and coronary events, these associations are likely causal. # Novelty and Significance {#article-title-44}

Urinary Proteome and Systolic Blood Pressure as Predictors of 5-Year Cardiovascular and Cardiac Outcomes in a General Population

In a previous cross-sectional study, we identified a multidimensional urinary classifier (HF1), which was associated with left ventricular dysfunction. We investigated whether HF1 predicts cardiovascular end points over and beyond traditional risk factors. In 791 randomly recruited Flemish (mean age, 51.2 years; 50.6% women), we quantified HF1 by capillary electrophoresis coupled with mass spectrometry. In addition, we measured cardiovascular risk factors. HF1 averaged −0.97 U (range, −3.26 to 2.60). Over 6.1 years (median), 35 participants died and 63, 45, and 22 experienced fatal or nonfatal cardiovascular, cardiac, or coronary events, respectively. The incidence of fatal combined with nonfatal cardiovascular and cardiac end points, standardized for sex and age, increased across thirds of the HF1 distribution (P⩽0.014), whereas trends for all-cause mortality and coronary events were nonsignificant (P≥0.10). The multivariable-adjusted hazard ratios (+1-SD) were 1.30 (95% confidence interval, 1.03–1.65; P=0.029) and 1.39 (1.06–1.84; P=0.018) for cardiovascular and cardiac events in relation to HF1. For systolic pressure, the corresponding estimates were 0.97 (0.74–1.28; P=0.85) and 0.93 (0.67–1.29; P=0.66), respectively. The HF1 upper thresholds optimized by maximizing Younden’s index were −0.50 and −0.36 U for cardiovascular and cardiac end points, respectively. Prognostic accuracy significantly (P⩽0.006) improved by adding HF1 to Cox models already including the other baseline predictors. Sensitivity analyses, from which we excluded 71 participants with previous cardiovascular disease, were confirmatory. In conclusion, over a 6-year period, the urinary proteome, but not systolic pressure, predicted cardiovascular and cardiac disease.

Longitudinal changes in left ventricular diastolic function in a general population.

Background—Data on changes in left ventricular diastolic function (LVDF) over time in the general population are sparse. We, therefore, investigated in the population cohort clinical correlates of longitudinal changes in Doppler diastolic indexes analyzed as continuous measures and assessed factors predictive of the changes in LVDF grades over time. Methods and Results—We measured early and late diastolic peak velocities of mitral inflow (E and A) by conventional Doppler, and the mitral annular velocities (e′ and a′) by tissue Doppler imaging in 650 participants (mean age, 50.7 years) at baseline and after 4.7 years (5th to 95th percentile, 3.7–5.4). In stepwise regression, the multivariable-adjusted correlates of the change in the transmitral and tissue Doppler imaging diastolic indexes included sex, age, baseline serum insulin, blood pressure, and heart rate. During follow-up, LVDF grades remained unchanged in 87.2% (95% confidence interval, 84.6%–89.8%), improved in 3.7% (95% confidence interval, 2.25%–5.15%), and worsened in 9.1% (95% confidence interval, 6.9%–11.3%). Baseline age was a strong predictor of worsening of LVDF from normal/mild grade to more advanced grade (odds ratio, 3.22; P<0.0001). A doubling of baseline insulin was associated with a 184% increase in the odds of worsening of LVDF (P<0.0001). Moreover, baseline diastolic blood pressure and the change in systolic blood pressure over time predicted worsening of LVDF (P⩽0.014). Conclusions—The key findings of this study are that LVDF tended to worsen over time and was associated with advanced age, higher baseline insulin level, and hemodynamic parameters, such as heart rate and blood pressure.

Design and feasibility of “PREMATurity as predictor of children's Cardiovascular–renal Health” (PREMATCH): A pilot study

Abstract The microvasculature and macrovasculature undergo extensive, organ-specific perinatal maturation. Multiple studies show associations between low birth weight and subsequent cardiovascular dysfunction in adulthood, suggesting that extreme preterm birth interferes with this maturation process. Therefore, we designed PREMATCH (PREMATurity as predictor of Cardiovascular–renal Health) to phenotype the microcirculation and macrocirculation during childhood in former preterm infants. A well-characterized cohort of former extreme preterm birth survivors and gender- and age-matched controls (aged 8–13 years) will be investigated for microvascular and macrovascular structure and function. In addition to cognitive performance and anthropometrics, we will investigate (i) the microvascular structure and function by endothelial function (photoplethysmography), sublingual capillary glycocalyx function (sidestream dark field imaging) and retinal structure (diameters of arterioles and venules); and (ii) the macrovascular phenotype by cardiac and renal ultrasound, repeated blood pressure measurements and arterial pulse-wave recordings. The PREMATCH study is unique in its design, and ongoing recruitment demonstrates excellent feasibility. The expectation is that the results of this study will identify risk factors during childhood for subsequent cardiovascular–renal disease in the adult life of former preterm infants, while further analysis on mediators in neonatal life of this cardiovascular–renal outcome may provide new information on perinatal risk factors. Trial registration: ClinicalTrials.gov identifier: NCT02147457.

Rationale and design of the Investigator-Steered Project on Intravascular Renal Denervation for Management of Drug-Resistant Hypertension (INSPiRED) trial.

Abstract The SYMPLICITY studies showed that renal denervation (RDN) is feasible as novel treatment for resistant hypertension. However, RDN is a costly and invasive procedure, the long-term efficacy and safety of which has not yet been proven. Therefore, we designed the INSPiRED trial to compare the blood pressure lowering efficacy and safety of RDN vs usual medical therapy. INSPiRED is a randomized controlled trial enrolling 240 treatment-resistant hypertensive patients at 16 expert hypertension centres in Belgium. Eligible patients, aged 20–69 years old, have a 24-h ambulatory blood pressure of 130 mmHg systolic or 80 mmHg diastolic or more, while taking at least three antihypertensive drugs. They are randomized to RDN (EnligHTNTM, SJM system) plus usual care (intervention group) or usual care alone (control group) in a ratio of 1:1. The primary endpoints for efficacy and safety, measured after 6 months, are the baseline-adjusted between-group differences in 24h systolic blood pressure and in glomerular filtration rate as estimated by the Chronic Kidney Disease Epidemiology Collaboration equation. Follow-up will continue up to 36 months after randomization. INSPiRED is powered to demonstrate a 10-mmHg difference in systolic blood pressure between randomized groups with a two-sided p-value of 0.01 and 90% power. It will generate long-term efficacy and safety data, identify the subset of treatment-resistant hypertensive patients responsive to RDN, provide information on cost-effectiveness, and by doing so INSPiRED will inform guideline committees and health policy makers. Trial registration: ClinicalTrials.gov identifier: NCT01505010.

Characteristics and Determinants of the Sublingual Microcirculation in Populations of Different Ethnicity

No previous population study assessed sublingual capillary density (CD) or perfused boundary region (PBR). Lower PBR indicates greater glycocalyx width. In 252 Han and 220 She Chinese and 254 Flemish people (mean age, 51.1 years; 54.7% women), representing random population samples, we measured total and perfused CD and PBR in the sublingual capillary bed, using oblique profiled epi-illumination, and cardiovascular risk factors. In multivariable analyses, we modeled ethnicity as random effect. Significance level was &agr;⩽0.05. Compared with Chinese, Flemish had lower total (577 versus 546 n°/mm2) and perfused (338 versus 320 n°/mm2) CD, but similar perfused-to-total CD ratio (mean, 0.59). Perfused-to-total CD ratio increased with age (effect size per 1–SD increase, +0.015 per year), body mass index (+0.008 per kg/m2), total cholesterol (+0.012 per mmol/L), and Framingham risk score (+0.018 per point) with no ethnic differences in these associations. For age and Framingham risk score, associations with perfused-to-total CD ratio were driven by positive relationships with perfused CD, whereas associations with total CD were nonsignificant. Chinese when compared with Flemish had higher hematocrit (43.0 versus 41.1%), PBR (2010 versus 1876 nm), and pulse rate (72.6 versus 63.3 bpm). PBR standardized for hematocrit, perfused CD, and pulse rate decreased with body mass index (–26.7 nm/kg/m2), mean arterial pressure (–30.6 nm/mm Hg), and diastolic pressure (–28.5 nm/mm Hg) with no ethnic differences in these associations. In conclusion, a higher cardiovascular risk profile is associated with functional recruitment of capillaries with preserved glycocalyx that protects the endothelial lining.

Prediction of acute coronary syndromes by urinary proteome analysis

Identification of individuals who are at risk of suffering from acute coronary syndromes (ACS) may allow to introduce preventative measures. We aimed to identify ACS-related urinary peptides, that combined as a pattern can be used as prognostic biomarker. Proteomic data of 252 individuals enrolled in four prospective studies from Australia, Europe and North America were analyzed. 126 of these had suffered from ACS within a period of up to 5 years post urine sampling (cases). Proteomic analysis of 84 cases and 84 matched controls resulted in the discovery of 75 ACS-related urinary peptides. Combining these to a peptide pattern, we established a prognostic biomarker named Acute Coronary Syndrome Predictor 75 (ACSP75). ACSP75 demonstrated reasonable prognostic discrimination (c-statistic = 0.664), which was similar to Framingham risk scoring (c-statistics = 0.644) in a validation cohort of 42 cases and 42 controls. However, generating by a composite algorithm named Acute Coronary Syndrome Composite Predictor (ACSCP), combining the biomarker pattern ACSP75 with the previously established urinary proteomic biomarker CAD238 characterizing coronary artery disease as the underlying aetiology, and age as a risk factor, further improved discrimination (c-statistic = 0.751) resulting in an added prognostic value over Framingham risk scoring expressed by an integrated discrimination improvement of 0.273 ± 0.048 (P < 0.0001) and net reclassification improvement of 0.405 ± 0.113 (P = 0.0007). In conclusion, we demonstrate that urinary peptide biomarkers have the potential to predict future ACS events in asymptomatic patients. Further large scale studies are warranted to determine the role of urinary biomarkers in clinical practice.

Renal glomerular dysfunction in relation to retinal arteriolar narrowing and high pulse pressure in seniors

Retinal arteriolar narrowing and high pulse pressure (PP) are associated with macrovascular complications and microvascular renal disease. Few studies addressed whether in seniors (⩾60 years) estimated glomerular filtration rate (eGFR) is independently related to central retinal arteriolar equivalent (CRAE) and PP. In 292 randomly recruited seniors (49.3% women; mean, 68.2 years), we measured PP by standard sphygmomanometry, CRAE (IVAN software), eGFR (Chronic Kidney Disease Epidemiology Collaboration equation) and stage of chronic kidney disease (CKD (Kidney Disease Outcomes Quality Initiative guideline)). Statistical methods included linear and logistic regression. PP, CRAE and eGFR averaged 59.2 mm Hg, 146.3 μm and 79.9 ml min−1 per 1.73 m2. Decline in eGFR (–2.27 ml min−1 per 1.73 m2 per 15 μm; P=0.011) occurred in parallel with CRAE narrowing. CRAE (effect size per 1-s.d. increment, –1.85 μm; P=0.032) and eGFR (–2.68 ml min−1 per 1.73 m2; P=0.003) both declined with higher PP. With PP increasing from 63 to 73 mm Hg (threshold for macrovascular complications), CRAE dropped by –4.70 μm (P⩽0.037). A 70-mm Hg PP threshold corresponded with a 150-μm CRAE cutoff. The risk of CKD (stage ⩾2 vs. 1; n=203 vs. 89) rose with CRAE <150 μm (odds ratio, 2.81; P<0.0001), but not with PP ⩾70 mm Hg (1.47; P=0.20). Additionally, CRAE added to PP increased the area under the curve from 0.58 to 0.64 (P=0.047) for identifying stage ⩾2 CKD. In seniors, CRAE and eGFR decline in parallel with higher PP. CRAE <150 μm identifies early decline in eGFR.

Diastolic left ventricular function in relation to urinary and serum collagen biomarkers in a general population

Current knowledge on the pathogenesis of diastolic heart failure predominantly rests on case-control studies involving symptomatic patients with preserved ejection fraction and relying on invasive diagnostic procedures including endomyocardial biopsy. Our objective was to gain insight in serum and urinary biomarkers reflecting collagen turnover and associated with asymptomatic diastolic LV dysfunction. We randomly recruited 782 Flemish (51.3% women; 50.5 years). We assessed diastolic LV function from the early and late diastolic peak velocities of the transmitral blood flow and of the mitral annulus. By sequencing urinary peptides, we identified 70 urinary collagen fragments. In serum, we measured carboxyterminal propeptide of procollagen type 1 (PICP) as marker of collagen I synthesis and tissue inhibitor of matrix metalloproteinase type 1 (TIMP-1), an inhibitor of collagen-degrading enzymes. In multivariable-adjusted analyses with Bonferroni correction, we expressed effect sizes per 1-SD in urinary collagen I (uCI) or collagen III (uCIII) fragments. In relation to uCI fragments, e’ decreased by 0.183 cm/s (95% confidence interval, 0.017 to 0.350; p = 0.025), whereas E/e’ increased by 0.210 (0.067 to 0.353; p = 0.0012). E/e’ decreased with uCIII by 0.168 (0.021 to 0.316; p = 0.018). Based on age-specific echocardiographic criteria, 182 participants (23.3%) had subclinical diastolic LV dysfunction. Partial least squares discriminant analysis contrasting normal vs. diastolic LV dysfunction confirmed the aforementioned associations with the uCI and uCIII fragments. PICP and TIMP-1 increased in relation to uCI (p<0.0001), whereas these serum markers decreased with uCIII (p≤0.0006). Diastolic LV dysfunction was associated with higher levels of TIMP-1 (653 vs. 696 ng/mL; p = 0.013). In a general population, the non-invasively assessed diastolic LV function correlated inversely with uCI and serum markers of collagen I deposition, but positively with uCIII. These observations generalise previous studies in patients to randomly recruited people, in whom diastolic LV function ranged from normal to subclinical impairment, but did not encompass overt diastolic heart failure.

Retinal microvascular diameter, a hypertension-related trait, in ECG-gated vs. non-gated images analyzed by IVAN and SIVA

The diameters of the retinal microvasculature reflect intermediate target organ damage and predict adverse health outcomes. In view of the pulsatility of the cerebral blood flow and refinement of software used for off-line analysis, we assessed the repeatability of retinal microvascular diameters in ECG-gated vs. non-gated images using nonmydriatic retinal photographs (Canon Cr-DGi visualization system) postprocessed by IVAN (Vasculomatic ala Nicola, version 1.1) or SIVA (Singapore I Vessel Assessment, version 3.6). Using these algorithms, we determined the central retinal arteriolar (CRAE) and venular (CRVE) equivalents and their ratio (arteriole-to-venule ratio (AVR)). The estimates of CRAE (mean, 158.5 μm), CRVE (222.5 μm) and AVR (0.71) in 10 volunteers were unaffected (P⩾0.059) by ECG gating. We assessed intragrader repeatability by the Bland and Altman approach in 30 participants with non-gated images and 30 with ECG-gated photographs. Repeatability, which was expressed as the percentage of near maximal variability (4-s.d. range), did not improve with ECG gating. Using SIVA, CRAE and CRVE were systematically larger (P⩽0.031), and the AVR estimates were similar (P⩾0.15) compared with IVAN. The differences (IVAN−SIVA) averaged −5.4 μm for CRAE, −3.9 μm for CRVE and −0.012 for AVR in the non-gated images and −3.3 μm, −6.9 μm and 0.006, respectively, in the ECG-gated photographs. In conclusion, ECG gating does not affect estimates of the retinal microvascular diameters or improve intragrader repeatability. SIVA yields slightly but significantly larger estimates of the retinal arteriolar and venular diameters. Combining historical readings analyzed by IVAN with more recent readings by SIVA is possible only for AVR and is not recommended for either CRAE or CRVE.