Ethnicity-specific myocardial remodelling in hypertensive heart disease by multi-parametric cardiovascular magnetic resonance

Background

Patients with systemic hypertension (HTN) of African ancestry (Afr-a) are at greater risk of incident heart failure (HF), hospitalisation and death than those of European ancestry (Eu-a). This has been related to higher prevalence of HTN-related target organ damage, including high level of circulating cardiac troponins, which is not fully explained by blood pressure level. Thus, one may speculate that Afr-a hypertensives have a higher tendency to develop myocardial damage in response to arterial afterload. However, myocardial composition differences between Afr-a and Eu-a hypertensives remain speculative.

Purpose

To investigate ethnic-specific differences in myocardial tissue composition in Eu-a and Afr-a hypertensives by multi-parametric cardiovascular magnetic resonance (CMR).

Methods

This cross-sectional study included 63 Afr-a and 47 Eu-a hypertensive patients. All patients underwent multi-parametric CMR (1.5-Tesla Aera, Siemens-Healthcare, Erlangen-Germany). Left (LV) and right ventricular (RV) volumes, mass and function, atrial dimensions, and myocardial tissue characterisation (including T1- and T2-mapping) were measured using a standardised imaging protocol, and post-processing recommendations from international scientific societies. Analysis was completed using a commercially available cardiac-software (CVI-42, Calgary-Canada). Central pulse-wave-velocity (PWV) between the ascending and proximal descending thoracic aorta was measured by high-temporal, resolution 2D phase-contrast velocity-encoded parasagittal cine images, using in-house MATLAB software.

Results

Although Afr-a were 5 years older than Eu-a hypertensives, cardiovascular risk factors, anthropometric, body composition and haemodynamic measures were similar between the two groups (Figure 1). Segmental PWV was greater in Afr-a than Eu-a patients (8.16±2.71 vs 6.97±2.82 m/s, P=0.044), underlying higher aortic stiffness in Afr-a hypertensives. Afr-a hypertensives also had greater LV mass and LV-mass/end-diastolic volume ratio than Eu-a (Figure 2), whilst no difference was observed in LV systolic/diastolic function. Native T1 relaxation time and synthetic extracellular volume were also similar between the two ethnicities, though T2 relaxation time was significantly higher in Afr-a hypertensives. Late gadolinium enhancement (LGE), a well-established metric of replacement fibrosis (scarring), was more prevalent in Afr-a than Eu-a hypertensives (14% vs 4%, P=0.001). In patients with LGE, the extent of LGE was higher in Afr-a than Eu-a hypertensives (Figure 2).

Conclusion

Afr-a hypertensives have higher arterial afterload, LV mass and remodelling than Eu-a, despite comparable mean blood pressure, body-mass-index, and body composition. These changes in LV structure and geometry were associated with higher T2 relaxation time, likely reflecting low-grade inflammation, as well as higher prevalence and extent of replacement myocardial fibrosis.

Funding Acknowledgement

Type of funding sources: None.

Racial differences of right ventricular remodelling in systemic hypertension unveiled by multiparametric cardiovascular magnetic resonance

Background

Patients with systemic hypertension (HTN) of African ancestry (Afr-a) are at greater risk of heart failure (HF), hospitalisation and death than those of European ancestry (Eu-a). Compelling evidence suggests that left ventricular (LV) remodelling and hypertrophy are more prevalent in Afr-a than Eu-a hypertensives due to either a high clustering of cardiovascular risk-factors and/or a difference in genetic background. Prior studies in Eu-a subjects have shown that uncomplicated HTN is associated with right ventricular (RV) hypertrophy and remodelling which may contribute to development of HF. However, the impact of ethnicity on RV remodelling in HTN remains speculative.

Purpose

To investigate the influence of ethnicity on RV remodelling/hypertrophy in patients with HTN using cardiovascular magnetic resonance (CMR).

Methods

In this cross-sectional study we included 16 Afr-a and 32 Eu-a age- and sex-matched healthy-volunteers, and 63 Afr-a and 47 Eu-a hypertensives. All participants underwent a CMR exam (1.5-Tesla, Aera, Siemens-Healthcare, Erlangen-Germany). LV and RV volumes, masses and function were measured according to the current recommendations. Blood pressure was recorded during the CMR.

Results

Age- and sex-matched Afr-a and Eur-a healthy-volunteers (37±10 vs 37±12 years, P=0.975; male 53% vs 44%; P=0.539) exhibited closely comparable LV and RV volumes, masses, and end-diastolic volume/mass ratios. In the HTN group, despite Afr-a hypertensives being roughly 5 years older than Eu-a, baseline characteristics including cardiovascular risk factors, mean blood pressure, body-mass-index, and body composition metrics were similar between the two groups (Figure 1). Afr-a hypertensives also had greater LV and RV masses and mass/end-diastolic volume ratios than Eur-a hypertensives (Figure 2). RV mass correlated with LV mass in both ethnic groups (r=0.593 in Eu-a and r=0.569 in Afr-a; both P<0.001). Multivariable linear regression analysis showed that RV mass was independently associated with African descendance after correction for major confounders including LV mass, biventricular volumes, and body composition.

Conclusion

Our findings support the notion that Afr-a and Eur-a healthy-volunteers have comparable left and right ventricular geometry and masses, arguing against genetic-determinate ventricular geometry and myocardial mass in this population. However, Afr-a individuals exhibit higher sensitivity to myocardial hypertrophy in response to HTN which translates into greater biventricular masses and remodelling, compared to Eu-a hypertensives.

Funding Acknowledgement

Type of funding sources: None.

Significance of trace elements in seminal plasma of infertile men

The seminal fluid has the important function as a vehicle for the transportation of the spermatozoa through the epididymis, the vas deferens, and urethra and into the vagina. Major changes in the level of trace elements like zinc, magnesium, and cadmium in semen appear to be related to abnormal spermatozoal function and fertilizing capacity. The aim of the study was to evaluate the pattern of trace elements in semen of subfertile men compared to levels in the blood. The relationship of the trace elements with spermatozoal parameters was also evaluated. As part of the infertility evaluation, semen and blood samples were collected from 50 males attending the combined infertility clinic at a maternity hospital after 3 days' abstinence. Semen analysis and hypo-osmotic swelling tests were done on fresh semen samples. The serum and remaining semen sample were stored at -20 degrees C until they were analyzed with atomic absorption spectrometry. No significant differences occurred in the levels of trace elements in normozoospermic, oligospermic, and azoospermic semen. However, significantly high levels of cadmium were detected in semen of men who were smokers and had asthenozoospermia (p < 0.001) compared with those who had normal motility. We conclude that the high level of cadmium in smokers with asthenozoospermia is evidence of the possible toxic effect of this trace element and this may be one of the causes of asthenozoospermia.