Troponin T release is associated with silent myocardial ischaemia in black men: The SABPA Study.

Background High sensitivity cardiac troponin T (hs-cTnT) is a validated marker of myocardial damage and may reflect the degree of silent myocardial ischaemia (SMI) and ventricular strain. Our aim was to compare hs-cTnT levels in black and white South Africans taking SMI into consideration. We further explored the capability of hs-cTnT to predict the presence of compensatory systolic hypertension in this South African cohort. Methods A bi-ethnic sex cohort ( n = 404) with similar socioeconomic status (198 black participants and 206 white participants, aged 20-65 years) participated in this target population study where 24 h ambulatory blood pressure, electrocardiogram and overnight fasting cardiometabolic variables were measured. Results Hypertension, higher glycated haemoglobin levels and more frequent and longer SMI events were observed more often in the black participants. Multivariate linear regression analysis showed positive associations between SMI events [Adj. R2 = 0.19; ß 0.35 (0.08-0.62); p < 0.01], SMI event maximum duration [Adj. R2 = 0.17, ß 0.43 (0.16-0.70), p < 0.01], SMI total duration [Adj. R2 = 0.12; ß 0.37 (0.10; 0.65), p = 0.05] and hs-cTnT in black males only.] A lower hs-cTnT cut-point ≥4.2 pg/ml for 24 h systolic hypertension was predicted in the black participants compared with ≥5.6 pg/ml in the white participants (area under the curve 0.66-67 (95% CI: 0.57-0.75), p < 0.001) with a respective sensitivity/specificity of 64/68% and 61/71%. Conclusions hs-cTnT may be a potential marker of SMI in the prediction of systolic blood pressure increases, as well as clusters of risk factors for cardiovascular disease. Ethnic- and possibly sex-specific references values for hs-cTnT should be considered for risk stratification.

Silent ischemia is associated with subclinical atherosclerosis in African males: the sympathetic activity and ambulatory blood pressure in Africans study.

Silent myocardial ischemia is a predictor of subclinical atherosclerosis driven by increased cardiovascular risk markers, although still unknown in Africans. The aim of this study was to assess if cardiovascular risk markers will be associated with subclinical atherosclerosis. African men were stratified into (i) 24-hour silent ischemia (SI, n = 38) and (ii) without (nSI, n = 40) groups. Ambulatory blood pressure (BP), SI, 12-lead resting electrocardiogram, ultrasound carotid intima-media thickness (CIMT) measurements, and fasting blood samples were obtained. Above-normal cardiovascular risk markers, that is, glucose level, heart rate, BP, and CIMT, were evident in men with SI. Hypertension prevalence was 89% in the African SI men as opposed to 64% in the nSI men. Regression analyses revealed that only SI events in SI men explained 35% (95% confidence interval [CI]: 0.22;0.52) of the variance in CIMT, while in all African men it explained 29% (95% CI: 0.19;0.39). In conclusion, SI was associated with structural vascular disease in African men. This could imply that SI is not necessarily driven by hypertension in African men but through other possible mechanisms such as increased sympathetic nervous system activity.