Cardiovascular Journal of Africa: Vol 28 No 3 (May/June 2017)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 3, May/June 2017 194 AFRICA
We know that renal dysfunction is a serious complication of
coronary revascularisation with CABG and results in increased
morbidity and mortality rates and prolonged hospital stay.18
The injurious action of CABG on renal function is caused
by several mechanisms, including non-pulsatile perfusion and
increased levels of circulating catecholamines, cytokines and
free haemoglobin.19 These effects result in damage to the
glomerular as well as tubular structures, which, in turn, may
cause renal dysfunction, especially in the presence of additional
risk factors.20-21
Microalbuminuria is one of the sensitive markers of increased
capillary permeability and may be useful to study the systemic
inflammatory response after CABG.6,22,23 According to previous
investigations, urinary microalbuminuria increased significantly
in the early postoperative period and one day after CABG.
In our study, peak increase in microalbuminuria was observed
in both groups but there was no statistically significant difference
(p = 0.071). These levels decreased, particularly on the fifth day in
our cases, and the decrease was statistically significantly different
in group T. In both groups, hsCRP increased and peaked on
the first postoperative day in both groups. However, in group
T, hsCRP, as one of the pro-inflammatory agents, decreased
significantly on the fifth day. Therefore, the increase in acute
inflammatory response was similar in both groups on the first
postoperative day, and in group T, both markers had decreased
by the fifth day.
Borch-Johnsen et al. showed the direct relationship between
proteinuria and cardiovascular mortality rate in insulin-
dependent diabetic patients after open-heart surgery in patients
undergoing CABG.24 Telmisartan was also shown to reduce or
normalise microalbuminuria in 34% of patients with diabetes,
and in a second, smaller study including 64 hypertensive
and 60 normotensive patients, to reduce the incidence of
renal dysfunction. This confirmed that telmisartan reduced
microalbuminuria independently of its blood pressure-lowering
effects. Restoration of normal urine albumin levels has also been
demonstrated by telmisartan.25
Our study showed that telmisartan reduced
microalbuminuria, not only pre-operatively, but also after
open-heart surgery. The return to baseline levels was also faster
than in group N-T. Angiotensin receptor blocking agents
decrease some of the postoperative acute inflammatory agents
in on-pump CABG patients with diabetes mellitus by lessening
the systemic consequences of renal dysfunction, and may have
additional cardiovascular effects by exerting beneficial effects
on endothelial tissue elsewhere in the body and within the
heart in this patients group. The cardiovascular benefits of
angiotensin receptor antagonists have been evaluated, not only
in terms of their ability to lower blood pressure, but also on
their ability to prevent strokes, cardiac events and target-organ
damage.14,16
Limitations of our study are the relatively small size of our
series and the lack of definite criteria for selection of patients
for this study. As most coronary patients are already being
treated with angiotensin receptor blocking agents, the results
of our study will not have a major impact on clinical practice.
Furthermore, it would have been better to test the predictive
value of microalbuminuria on prognosis in this category of
patients. However, we hope that this study will pioneer further
studies on this method.
Conclusion
Our results showed that telmisartan decreased systemic
inflammation and urinary albumin excretion in diabetic patients
after CABG surgery, compared to those not taking angiotensin
receptor antagonists. These beneficial effects of telmisartan
treatment on diabetic patients after CABG should be investigated
further in prospective, randomised studies.
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