Yap-Hang Chan

Vitamin D Deficiency Is Associated with Depletion of Circulating Endothelial Progenitor Cells and Endothelial Dysfunction in Patients with Type 2 Diabetes

CONTEXT Vitamin D (Vit-D) deficiency is associated with type 2 diabetes mellitus (DM) and endothelial dysfunction. The relationship of Vit-D deficiency with circulating endothelial progenitor cells and endothelial dysfunction in type 2 DM patients nonetheless remains unclear. OBJECTIVE We aimed to investigate the cross-sectional association of Vit-D status with brachial flow-mediated dilation (FMD) and circulating endothelial progenitor cell (EPC) numbers in type 2 DM patients. DESIGN, SETTING, AND PARTICIPANTS We conducted a cross-sectional study of 280 patients (59% male, aged 68 ± 10 yr) with type 2 DM recruited in outpatient clinics during the winter period. MAIN OUTCOME MEASURE We measured serum 25-hydroxyvitamin D [25(OH)D] by an ELISA kit, circulating CD34+/kinase insert domain-containing receptor (KDR)+ and CD133+/KDR+ EPCs by flow cytometry and brachial artery FMD by vascular ultrasound, respectively. RESULTS The mean serum 25(OH)D concentration was 25.00 ± 9.17 ng/ml, and 34.3% of patients had Vit-D deficiency [25(OH)D < 20 ng/ml]. Serum 25(OH)D concentration had a significant correlation with hemoglobin A1c level [B = -0.018, 95% confidence interval (CI) -0.035 to -0.002, P = 0.032]. Patients with Vit-D deficiency status had significantly lower brachial FMD (mean difference -1.43%, 95% CI -2.31 to -0.55, P = 0.001) and CD133+/KDR+EPC counts (mean difference -0.12%, 95% CI -0.21 to -0.019, P = 0.022) than those with sufficient Vit-D status after adjustment for age, sex, and cardiovascular risk factors, including hemoglobin A1c levels. CONCLUSIONS Our results demonstrate that serum 25(OH)D status was significantly associated with brachial artery FMD and circulating CD133+/KDR+EPCs. This suggests that Vit-D deficiency might contribute to depletion of EPCs and endothelial dysfunction in patients with type 2 DM.

Reduction of C-reactive protein with isoflavone supplement reverses endothelial dysfunction in patients with ischaemic stroke.

AIMS To investigate the effect of oral isoflavone supplement on vascular endothelial function in patients with established cardiovascular disease. METHODS AND RESULTS A randomized, double-blinded, placebo-controlled trial was performed to determine the effects of isoflavone supplement (80 mg/day, n = 50) vs. placebo (n = 52) for 12 weeks on brachial flow-mediated dilatation (FMD) in patients with prior ischaemic stroke. Compared with controls, FMD at 12 weeks was significantly greater in isoflavone-treated patients [treatment effect 1.0%, 95% confidence interval (95% CI) 0.1-2.0, P = 0.035]. Adjusted for baseline differences in FMD, isoflavone treatment was independently associated with significantly less impairment of FMD at 12 weeks (odds ratio 0.32, 95% CI 0.13-0.80, P = 0.014). The absolute treatment effect of isoflavone on brachial FMD was inversely related to baseline FMD (r = -0.51, P < 0.001), suggesting that vasoprotective effect of isoflavone was more pronounced in patients with more severe endothelial dysfunction. Moreover, isoflavone treatment for 12 weeks resulted in a significant decrease in serum high-sensitivity (hs)-C-reactive protein level (treatment effect -1.7 mg/L, 95% CI -3.3 to -0.1, P = 0.033). Nevertheless, isoflavone did not have any significant treatment effects on nitroglycerin-mediated dilatation, blood pressure, heart rate, serum levels of fasting glucose and insulin, haemoglobin A1c, and oxidative stress as determined by serum superoxide dismutase, 8-isoprostane, and malondialdehyde (all P > 0.05). CONCLUSION This study demonstrated that 12 week isoflavone treatment reduced serum hs-C-reactive protein and improved brachial FMD in patients with clinically manifest atherosclerosis, thus reversing their endothelial dysfunction status. These findings may have important implication for the use of isoflavone for secondary prevention in patients with cardiovascular disease, on top of conventional interventions.

Risk of ischemic stroke after new-onset atrial fibrillation in patients with hyperthyroidism

BACKGROUND Hyperthyroidism is one of the most common reversible causes of atrial fibrillation (AF); nevertheless, the risk of ischemic stroke in patients with hyperthyroidism who present with new-onset AF is unclear. OBJECTIVE This study sought to investigate the clinical outcome of hyperthyroidism-induced AF with regard to risk of ischemic stroke risk. METHODS We prospectively studied the incidence, time course, and clinical predictors for ischemic stroke in patients with hyperthyroidism-induced AF (n = 160). They were compared with age- and sex-matched cohorts of hyperthyroid patients without AF (n = 160) and AF patients without hyperthyroidism (n = 160). RESULTS Baseline characteristics were comparable among the 3 groups. At 1 year, 86 hyperthyroid patients with AF (54%) and 92 patients with nonthyroid AF (58%) had spontaneous or pharmacological sinus conversion (P = .20). Ischemic stroke was observed in 15 hyperthyroid patients with AF (9.4%) versus 5 patients with nonthyroid AF (3.1%, P = .02), and 1 hyperthyroid patient without AF (0.6%, P < .001). Furthermore, the majority of ischemic stroke (>70%) in patients with AF occurred within the first 30 days of presentation, whereas AF was still present. Cox regression analysis showed that hyperthyroidism (hazard ratio [HR]: 3.5, 95% confidence interval [CI]: 1.15 to 10.42, P = .03) and persistent AF (HR: 13.0, 95% CI: 2.88 to 58.80, P < .01) predicted the occurrence of ischemic stroke; warfarin therapy reduced the risk of ischemic stroke (HR: 0.17, 95% CI: 0.04 to 0.79, P = .02). CONCLUSION In hyperthyroid patients who presented with new-onset AF, there was an increased risk of ischemic stroke clustering during the initial phase of presentation. This should prompt early use of anticoagulation therapy in hyperthyroid patients with AF.

Prognostic implications of surrogate markers of atherosclerosis in low to intermediate risk patients with Type 2 Diabetes

BackgroundType 2 diabetes mellitus (T2DM) patients are at increased risk of developing cardiovascular events. Unfortunately traditional risk assessment scores, including the Framingham Risk Score (FRS), have only modest accuracy in cardiovascular risk prediction in these patients.MethodsWe sought to determine the prognostic values of different non-invasive markers of atherosclerosis, including brachial artery endothelial function, carotid artery atheroma burden, ankle-brachial index, arterial stiffness and computed tomography coronary artery calcium score (CACS) in 151 T2DM Chinese patients that were identified low-intermediate risk from the FRS recalibrated for Chinese (<20% risk in 10 years). Patients were prospectively followed-up and presence of atherosclerotic events documented for a mean duration of 61 ± 16 months.ResultsA total of 17 atherosclerotic events in 16 patients (11%) occurred during the follow-up period. The mean FRS of the study population was 5.0 ± 4.6% and area under curve (AUC) from receiver operating characteristic curve analysis for prediction of atherosclerotic events was 0.59 ± 0.07 (P = 0.21). Among different vascular assessments, CACS > 40 had the best prognostic value (AUC 0.81 ± 0.06, P < 0.01) and offered significantly better accuracy in prediction compared with FRS (P = 0.038 for AUC comparisons). Combination of FRS with CACS or other surrogate vascular markers did not further improve the prognostic values over CACS alone. Multivariate Cox regression analysis identified CACS > 40 as an independent predictor of atherosclerotic events in T2DM patients (Hazards Ratio 27.11, 95% Confidence Interval 3.36-218.81, P = 0.002).ConclusionsIn T2DM patients identified as low-intermediate risk by the FRS, a raised CACS > 40 was an independent predictor for atherosclerotic events.

Comparison of atrial fibrillation recurrence rates after successful electrical cardioversion in patients with hyperthyroidism-induced versus non-hyperthyroidism-induced persistent atrial fibrillation.

Hyperthyroidism-induced atrial fibrillation (AF) often spontaneously reverts to sinus rhythm after the return of euthyroid state, but a significant number of patients remain in persistent AF, which requires electrical cardioversion. The long-term outcome of hyperthyroidism-induced persistent AF after successful cardioversion remains unclear. The study group consisted of 58 patients with hyperthyroidism-induced persistent AF (mean age 57 +/- 2 years, 72% men) who had undergone successful electrical cardioversion. The AF recurrence rate was prospectively studied and compared with age- and gender-matched controls with persistent AF of nonthyroid origins. After a 24-month follow-up period, 34 patients (59%) had developed AF recurrence, significantly fewer than among controls (83%) (hazard ratio 0.64, 95% confidence interval 0.39 to 0.97, p = 0.04). Cox regression analysis showed that long AF duration was the only predictor of AF recurrence in patients with hyperthyroidism-induced persistent AF. In conclusion, hyperthyroidism-induced persistent AF carries a lower recurrence rate after conversion to sinus rhythm than non-hyperthyroidism-induced persistent AF, and early electrical cardioversion should be considered.

Use of aspirin in Chinese after recovery from primary intracranial haemorrhage

Intracranial haemorrhage (ICH) accounts for ~35% of all strokes in Chinese. Anti-platelet agent is often avoided after an index event due to the possibility of recurrent ICH. This single-centered observational study included 440 consecutive Chinese patients with a first spontaneous ICH surviving the first month performed during 1996-2010. The subjects were identified, and their clinical characteristics, anti-platelet therapy after ICH, and outcomes including recurrent ICH, ischaemic stroke, and acute coronary syndrome were checked from hospital records. Of these 440 patients, 56 patients (12.7%) were prescribed aspirin (312 patient-aspirin years). After a follow-up of 62.2 ± 1.8 months, 47 patients had recurrent ICH (10.7%, 20.6 per 1,000 patient years). Patients prescribed aspirin did not have a higher risk of recurrent ICH compared with those not prescribed aspirin (22.7 per 1,000 patient-aspirin years vs. 22.4 per 1,000 patient years, p=0.70). Multivariate analysis identified age > 60 years (hazard ratio [HR]: 2.0, 95% confidence interval [CI]: 1.07-3.85, p=0.03) and hypertension (HR: 2.0, 95% CI: 1.06-3.75, p=0.03) as independent predictors for recurrent ICH. In a subgroup analysis including 127 patients with standard indications for aspirin of whom 56 were prescribed aspirin, the incidence of combined vascular events including recurrent ICH, ischaemic stroke, and acute coronary syndrome was statistically lower in patients prescribed aspirin than those not prescribed aspirin (52.4 per 1,000 patient-aspirin years, vs. 112.8 per 1,000 patient-years, p=0.04). In conclusion, we observed in a cohort of Chinese post-ICH patients that aspirin use was not associated with an increased risk for a recurrent ICH.

Association of subclinical myocardial injury with arterial stiffness in patients with type 2 diabetes mellitus.

ObjectiveType 2 diabetes mellitus (T2DM) is associated with subclinical myocardial injury although the underlying mechanism is uncertain. We postulated that arterial stiffness, endothelial dysfunction and subclinical atherosclerosis may contribute to subclinical myocardial injury in patients with T2DM.MethodsSerum high-sensitivity troponin I (hs-TNI) an indicator of myocardial injury, was measured in 100 patients with T2DM without clinical evidence of macrovascular disease and 150 age and gender-matched controls. Elevated hs-TnI was defined as follow (derived from the 99th percentile from controls): Male >11.1 ng/L; female >7.6 ng/L. Measures that may contribute to myocardial damage in patients with T2DM, including brachial-ankle pulse wave velocity (ba-PWV), brachial flow mediated dilatation (FMD) and carotid intima media thickness (IMT), were also assessed.ResultsThe serum level of hs-TNI (5.7±9.2 μg/L vs. 3.2±1.9 μg/L, P< 0.01) and the prevalence of elevated hs-TNI (12% vs. 4%, P = 0.02) were significantly higher in patients with T2DM than controls. Patients with T2DM also had significantly worse ba-PWV (17.98±3.91ms-1 vs. 15.70±2.96 ms-1), brachial FMD (2.6±3.5% vs. 5.5±4.2%, P< 0.01) and carotid IMT (0.96±0.20 mm vs. 0.86±0.14 mm, P< 0.01). In patients with T2DM, hs-TNI was positively correlated with systolic blood pressure (r = 0.31, P<0.01), serum creatinine (r = 0.26, P = 0.01) and ba-PWV (r = 0.34, P< 0.01). Importantly, multiple regression revealed that only ba-PWV was independently associated with hs-TNI (β = 0.25, P = 0.04).ConclusionThe results demonstrated an independent association between ba-PWV and hs-TNI in patients with T2DM with no clinical evidence of macrovascular disease. These findings suggest that increased arterial stiffness is closely related to subclinical myocardial injury in patients with T2DM.

The CHADS2 and CHA2DS2-VASc scores predict adverse vascular function, ischemic stroke and cardiovascular death in high-risk patients without atrial fibrillation: Role of incorporating PR prolongation

OBJECTIVES To investigate whether the CHADS2 and CHA2DS2-VASc scores have clinical utility for prediction of adverse vascular function and vascular dysfunction-mediated incident cardiovascular (CV) events among high-risk patients without atrial fibrillation (AF), and the additional value of incorporating PR prolongation to the scores. METHODS We analyzed 579 high-risk CV outpatients without clinical AF in a prospective cohort for new-onset ischemic stroke, myocardial infarction (MI), congestive heart failure (CHF), and CV death. Brachial flow-mediated dilation (FMD) and nitroglycerin-mediated dilatation (NMD), carotid intima-media thickness (IMT) and pulse wave velocity (PWV) were determined. RESULTS Baseline CHADS2 score was associated with lower FMD (Pearson r = -0.16, P < 0.001) and NMD (r = -0.17, P < 0.001), higher carotid IMT (r = 0.30, P < 0.001) and PWV (r = 0.35, P < 0.001; similar for CHA2DS2-VASc score: All P < 0.05). After follow-up of 63 ± 11 months, 82 patients (14.2%) developed combined CV endpoint. ROC curve analysis showed that both CHADS2 and CHA2DS2-VASc scores were predictors for ischemic stroke (C-Statistic: CHADS2 0.70, P = 0.004; CHA2DS2-VASc 0.68, P = 0.010), MI (CHADS2 0.63, P = 0.030; CHA2DS2-VASc 0.70, P = 0.001), and CV death (CHADS2 0.63, P = 0.022; CHA2DS2-VASc 0.65, P = 0.011). Higher CHADS2 score was associated with reduced event-free survival from combined CV endpoints (log-rank = 16.7, P < 0.001) with differences potentiated if stratified by CHA2DS2-VASc score (log-rank = 29.2, P < 0.001). Incorporating PR prolongation, the CHA2DS2-VASc-PR score achieved the highest C-Statistic for CV death prediction (0.70, P < 0.001) superior to the CHADS2 score (chi-square: 12.1, P = 0.0005). CONCLUSIONS The CHADS2 and CHA2DS2-VASc predict vascular dysfunction and cardiovascular events in high-risk CV patients without clinical AF, with further improved performance incorporating PR prolongation.

Mediterranean-Style Diet Is Associated With Reduced Blood Pressure Variability and Subsequent Stroke Risk in Patients With Coronary Artery Disease

BACKGROUND AND PURPOSE The Mediterranean-style diet is widely advocated for the prevention of cardiovascular diseases (CVD). Meanwhile, blood pressure variability (BPV) is a novel risk factor for CVD. It is unknown whether dietary pattern plays a role in modulating BPV. METHODS We prospectively followed-up 274 consecutive patients with stable coronary artery disease (CAD). The Mediterranean diet score (MDS) was derived for all individuals upon recruitment, blood pressure (BP) was measured during each subsequent clinic visit and the visit-to-visit BPV was calculated. The occurrence of major adverse cardiovascular events (MACEs) and all-cause mortality was monitored. RESULTS After a mean follow-up of 77±12 months, 16.1% of the study population developed MACEs. About 11.3% died from all causes. Patients who developed MACEs or all-cause mortality had a greater systolic BPV compared to those who did not develop an adverse event. Patients who developed a MACE had a lower MDS and further analysis revealed those who developed a stroke had a lower MDS compared with those who did not develop a stroke, but there were no significant differences in MDS between CAD patients with or without subsequent acute coronary syndrome, cardiovascular, or all-cause mortality. After adjusting for confounding variables, a high MDS was an independent predictor for low systolic BPV (B -0.74, 95% confidence interval -1.27 to -0.21, P < 0.01) and was noted to be protective against subsequent development of stroke (hazards ratio 0.48, 95% confidence interval 0.24 to 0.94, P = 0.03). CONCLUSIONS Among patients with CAD, a higher MDS is associated with a lower visit-to-visit BPV and with lower stroke risk.

Secular trends of salted fish consumption and nasopharyngeal carcinoma: a multi-jurisdiction ecological study in 8 regions from 3 continents

BackgroundDespite salted fish being a classical risk factor of Nasopharyngeal Carcinoma (NPC), whether secular trends in salted fish consumption worldwide accounted for changes in NPC rates were unknown. The relationship between vegetable and cigarette consumption to NPC risk worldwide were also largely uncertain. We investigated the longitudinal trends in standardised NPC incidence/mortality rates across 8 regions and their associations with secular trends in salted fish, vegetable and tobacco consumptions.MethodsAge standardised mortality rate (ASMR) and age standardised incidence rate (ASIR) of NPC were obtained from the WHO cancer mortality database and Hong Kong Cancer Registry. Per capita consumption of salted fish, tobacco and vegetables in Hong Kong and 7 countries (China, Finland, Japan, Portugal, Singapore, United Kingdom and United States) were obtained from the Food and Agriculture Organization of the United Nation (FAO) and Hong Kong Trade and Census Statistics. Pearson correlation and multivariate analysis were performed to examine both crude and adjusted associations.ResultsThere were markedly decreasing trends of NPC ASIR and ASMR in Hong Kong over the past three decades, which were correlated with corresponding secular changes in salted fish consumption per capita (Pearson r for 10 cumulative years : ASIR = 0.729 (male), 0.674 (female); ASMR = 0.943 (male), 0.622 (female), all p < 0.05 except for female ASMR). However such associations no longer correlated with adjustments for decreasing tobacco and increasing vegetable consumption per capita (Pearson r for 10 cumulative years: ASIR = 2.007 (male), 0.339 (female), ASMR = 0.289 (male), 1.992 (female), all p > 0.05). However, there were no clear or consistent patterns in relations between NPC ASIR and ASMR with salted fish consumption across 7 regions in 3 continents.ConclusionsOur results do not support the notion that changes in salted fish consumption had played an important role in explaining secular trends of NPC rates in Hong Kong and worldwide. Further studies should explore other lifestyle and genetic factors. However, our findings do support the potentially protective effects of vegetable consumption against NPC.