Cardiovascular Journal of Africa: Vol 27 No 5 (September/October 2016)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 5, September/October 2016

AFRICA

297

In studies related to the aetiopathogenesis of hypertension,

a Mg deficiency was reported to have hypertensive effects, and

dietary Mg intake was related to hypotension, showing the

reverse positive relationship between blood pressusure and

serum Mg levels.

The basic mechanism at play is blood pressure

regulation by Mg via modulating vascular tone and reactivity.

The direct vascular effect of Mg was first suggested in early

1990 in a study in which Mg salt infusion was reported to have a

blood pressure-lowering effect by decreasing peripheral vascular

resistance, with a mild increase in myocardial contractility.

Observational studies support these clinical findings and acute

Mg infusion causes hypotension via its vasodilatory effect.

Similar to previous studies, our research found CAE to

be significantly more prevalent in males.

1,2,4

Although serum

creatinine levels were in the normal range in all our study groups,

there was a statistically significant difference between the groups,

due possibly to small differences in creatinine levels. However

in the review by Cunningham and colleagues, it was reported

that in the early stages of renal failure, there was no change in

Mg metabolism but in the end stage, Mg levels were affected.

Therefore normal creatinine levels in our study groups probably

did not affect the Mg balance.

In our study, there was a significant difference in HDL

cholesterol levels between the groups. In a study by Randell and

colleagues, HDL cholesterol levels were found to be positively

correlated with Mg levels. Our results are consistent with this

study, showing higher Mg and HDL cholesterol levels in isolated

ectasia and lower levels in CAD patients, indicating that there

was no impact of this correlation on our results.

In our study, serum Mg levels were statistically higher in

isolated ectasia patients than in the NCA and CAD groups. Mg

levels were lowest in the CAD group. Mg levels in the CAD

CAE group were higher than in the NCA group but lower than

in the isolated ectasia group. The higher levels of Mg in the CAD

CAE than in the CAD group reached statistical significance.

White blood cell count, as an indicator of inflammation, was

significantly lower in isolated ectasia patients than in the CAD

group, relating to the anti-inflammatory effect of Mg. Another

inflammatory marker, ESR, was also found to be higher in CAD

patients than in isolated ectasia patients. Mg in the extracellular

fluid constitutes only 1% of the total body Mg concentration.

However our findings suggest that chronically higher levels of

serum Mg, with its anti-inflammatory effects, play a crucial

role in the pathogenesis of ectasia by leading to vasodilation

and negative remodelling. We proposed that factors other than

atherosclerosis may play an important role in ectasia formation.

Conclusion

The histopathological characteristics of patients with CAE were

similar to those with CAD. The specific mechanism of abnormal

luminal dilatation seen in CAE however remains to be elucidated.

Mg is a divalent cation with powerful vasodilatory effects. In our

study, serum Mg levels were found to be statistically higher in

ectasia patients with or without CAD.

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