Wen-Yi Yang

Meta-analysis of randomized controlled trials of renal denervation in treatment-resistant hypertension

Abstract Objective. The blood pressure (BP)-lowering effect of renal sympathetic nervous denervation (RDN) in resistant hypertension (rHT) shows large variation among studies. Methods. We meta-analyzed summary statistics of randomized clinical trials on RDN in rHT. For continuous outcomes, we assessed heterogeneity by Cochrans Q test and used random-effect models weighted for the inverse of the variance. We assessed safety by assessing the risk of major adverse events from stratified contingency tables. Results. Of 5652 patients screened in seven trials, 985 (17.4%) qualified and were randomized to control (n = 397) or RDN with SYMPLICITY™ catheters (n = 588). Follow-up was 6 months. In both control and RDN patients, antihypertensive treatment was continued or optimized. At enrolment, age averaged 58.1 years, systolic/diastolic office and 24 h BP 168.5/93.3 mmHg and 151.8/86.1 mmHg, respectively, and estimated glomerular filtration rate (eGFR) 79.3 ml/min/1.73 m². For BP outcomes, there was heterogeneity among trials. Pooled effects (control minus RDN) were −4.9/−3.5 mmHg (95% confidence interval, −20.9 to 11.1/−8.9 to 1.9) for office BP, −2.8/−1.5 mmHg (−6.5 to 0.8/−3.3 to 0.4) for 24 h BP and 0.81 ml/min/1.73 m² (−1.69 to 3.30) for eGFR. Removing one trial at a time produced confirmatory results. Adverse events occurred in 7.4% and 9.9% of control and RDN patients, respectively (p = 0.24). Conclusion. In selected rHT patients maintained on antihypertensive drugs, RDN with the SYMPLICITY systems does not significantly decrease BP but is safe. Future trials with next-generation catheters should aim at identifying responders in patients with evidence of sympathetic nervous overactivity.

Vitamin K Dependent Protection of Renal Function in Multi-ethnic Population Studies

Background Following activation by vitamin K (VK), matrix Gla protein (MGP) inhibits arterial calcification, but its role in preserving renal function remains unknown. Methods In 1166 white Flemish (mean age, 38.2 years) and 714 South Africans (49.2% black; 40.6 years), we correlated estimated glomerular filtration (eGFR [CKD-EPI formula]) and stage of chronic kidney disease (CKD [KDOQI stages 2–3]) with inactive desphospho-uncarboxylated MGP (dp-ucMGP), using multivariable linear and logistic regression. Results Among Flemish and white and black Africans, between-group differences in eGFR (90, 100 and 122 mL/min/1.73 m2), dp-ucMGP (3.7, 6.5 and 3.2 μg/L), and CKD prevalence (53.5, 28.7 and 10.5%) were significant, but associations of eGFR with dp-ucMGP did not differ among ethnicities (P ≥ 0.075). For a doubling of dp-ucMGP, eGFR decreased by 1.5 (P = 0.023), 1.0 (P = 0.56), 2.8 (P = 0.0012) and 2.1 (P < 0.0001) mL/min/1.73 m2 in Flemish, white Africans, black Africans and all participants combined; the odds ratios for moving up one CKD stage were 1.17 (P = 0.033), 1.03 (P = 0.87), 1.29 (P = 0.12) and 1.17 (P = 0.011), respectively. Interpretation In the general population, eGFR decreases and CKD risk increases with higher dp-ucMGP, a marker of VK deficiency. These findings highlight the possibility that VK supplementation might promote renal health.

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.

Additive Prognostic Value of Left Ventricular Systolic Dysfunction in a Population-Based Cohort

Background—Techniques of 2-dimensional speckle tracking enable the measurement of myocardial deformation (strain) during systole. Recent clinical studies explored the prognostic role of left ventricular global longitudinal strain (GLS). However, there are few data on the association between cardiovascular outcome and GLS in the community. Therefore, we hypothesized that GLS contains additive prognostic information over and beyond traditional cardiovascular risk factors in a large, population-based cohort. Methods and Results—We measured GLS by 2-dimensional speckle tracking in the apical 4-chamber view in 791 participants (mean age 50.9 years). We calculated multivariable adjusted hazard ratios for midwall, endocardial, and epicardial GLS, while accounting for family cluster and cardiovascular risk factors. Median follow-up was 7.9 years (5th to 95th percentile, 3.7–9.6). In continuous analysis, with adjustments applied for covariables, midwall, endocardial, and epicardial GLS were significant predictors of fatal and nonfatal cardiovascular (n=96; P<0.0001) and cardiac events (n=68; P⩽0.001). In the sex-specific low quartile of midwall GLS (<18.8% in women and <17.4% in men), the risk was significantly higher than the average population risk for cardiovascular (128%, P<0.0001) and cardiac (94%, P=0.0007) events. We also noticed that the risk for cardiovascular events increased with increasing number of left ventricular abnormalities, such as low GLS, diastolic dysfunction, and hypertrophy (log-rank P<0.0001). Conclusions—Low GLS measured by 2-dimensional speckle tracking predicts future cardiovascular events independent of conventional risk factors. Left ventricular midwall strain represents a simple echocardiographic measure, which might be used for assessing cardiovascular risk in a population-based cohort.

Diurnal Blood Pressure Rhythmicity in Relation to Environmental and Genetic Cues in Untreated Referred Patients

No previous study has addressed the relative contributions of environmental and genetic cues to the diurnal blood pressure rhythmicity. From 24-hour ambulatory recordings of systolic blood pressure obtained in untreated patients (51% women; mean age, 51 years), we computed the night-to-day ratio in 897 and morning surge in 637. Environmental cues included season, mean daily outdoor temperature, atmospheric pressure, humidity and weekday, and the genetic cues 14 single nucleotide polymorphisms in 10 clock genes. Systolic blood pressure averaged (±SD) 126.7±11.9 mm Hg, night-to-day ratio 0.86±0.07, and morning surge 24.8±10.7 mm Hg. In adjusted analyses, night-to-day ratio was 2.4% higher in summer and 1.8% lower in winter (P<0.001) compared with the annual average with a small effect of temperature (P=0.079); morning surge was 1.7 mm Hg lower in summer and 1.1 mm Hg higher in winter (P<0.001). The other environmental cues did not add to the night-to-day ratio or morning surge variance (P≥0.37). Among the 14 genetic variations, only CLOCK rs180260 was significantly associated with morning surge after adjustment for season, temperature, and other host factors and after Bonferroni correction (P=0.044). In CLOCK rs1801260 C allele carriers (n=83), morning surge was 3.7 mm Hg higher than in TT homozygotes (n=554). Of the night-to-day ratio and morning surge variance, season and temperature explained ≈8% and ≈3%, while for genetic cues, these proportions were ≈1% or less. In conclusion, environmental compared with genetic cues are substantially stronger drivers of the diurnal blood pressure rhythmicity.

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.

Left ventricular function in relation to chronic residential air pollution in a general population

Background In view of the increasing heart failure epidemic and awareness of the adverse impact of environmental pollution on human health, we investigated the association of left ventricular structure and function with air pollutants in a general population. Methods In 671 randomly recruited Flemish (51.7% women; mean age, 50.4 years) we echocardiographically assessed left ventricular systolic strain and strain rate and the early and late peak velocities of transmitral blood flow and mitral annular movement (2005−2009). Using subject-level data, left ventricular function was cross-sectionally correlated with residential long-term exposure to air pollutants, including black carbon, PM2.5, PM10 (particulate matter) and nitrogen dioxide (NO2), while accounting for clustering by residential address and confounders. Results Annual exposures to black carbon, PM2.5, PM10 and NO2 averaged 1.19, 13.0, 17.7, and 16.8 µg/m3. Systolic left ventricular function was worse (p ≤ 0.027) with higher black carbon, PM2.5, PM10 and NO2 with association sizes per interquartile interval increment ranging from −0.339 to −0.458% for longitudinal strain and from −0.033 to −0.049 s−1 for longitudinal strain rate. Mitral E and a′ peak velocities were lower (p ≤ 0.021) with higher black carbon, PM2.5 and PM10 with association sizes ranging from −1.727 to −1.947 cm/s and from −0.175 to −0.235 cm/s, respectively. In the geographic analysis, the systolic longitudinal strain sided with gradients in air pollution. The path analysis identified systemic inflammation as a possible mediator of associations with black carbon. Conclusions Long-term low-level air pollution is associated with subclinical impairment of left ventricular performance and might be a risk factor for heart failure.

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.

Diastolic Left Ventricular Function in Relation to Circulating Metabolic Biomarkers in a General Population

Background The metabolic signature associated with subclinical diastolic left ventricular (LV) dysfunction in the population remains ill defined. Methods and Results In 711 randomly recruited Flemish (50.8% women; mean age, 50.8 years), we assessed echocardiographic Doppler indexes of diastolic LV function in relation to 44 circulating metabolites determined by nuclear magnetic resonance spectroscopy. In multivariable‐adjusted regression analysis with Bonferroni correction of significance levels applied, peak a’ decreased (P≤0.048) and e’/a’ increased (P≤0.044) with circulating tyrosine, high‐density lipoprotein apolipoproteins, glucose+glutamine, and an unidentified molecule. Effect sizes expressed per 1‐SD increment in the metabolite ranged from −0.277 to −0.203 cm/s for peak a’ and from +0.047 to +0.054 for e’/a’. In addition, peak a’ decreased (P≤0.031) with glucose+2‐aminobutyrate (−0.261 cm/s) and glucose+2‐phosphoglycerate (−0.209 cm/s). In partial least square discriminant analysis (PLS‐DA), metabolites associated with normal diastolic LV function (n=538) included glucose+glutamine, glucose+2‐aminobutyrate, and glucose+2‐phosphoglycerate, whereas those siding with abnormal function encompassed 4‐aminobutyrate, 4‐hydroxybutyrate, creatinine, and phosphocholine. In receiver operating characteristics plots, adding 3 latent factors identified by PLS‐DA to prohormone brain natriuretic peptide increased (P<0.0001) the area under the curve from 0.64 (95% CI, 0.58–0.68) to 0.73 (0.68–0.78). Conclusions In a general population, circulating metabolites indicative of energy substrate utilization and protection against oxidative stress differentiated normal from abnormal diastolic LV function. These findings improve our understanding of the pathophysiology underlying deterioration of diastolic LV function and potentially point to new targets for prevention and treatment of this condition.

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.