[Hypotension during acute myocardial infarct. Different pattern of parameters of renal function in relation to the...

The influence on renal function caused by acute myocardial infarction complicated by hypotension has been studied. Particularly, a possible difference in renal functional pattern related to different localization and/or extension of necrotic myocardial area was investigated.

The study has been performed in 12 cases of acute myocardial infarction, involving anteroseptal (7) or inferodorsal (5) myocardial wall. The score of parietal asynergy resulted 13.28 in anterior vs 7.6 in inferior localization (p < 0.001).

The decrease in systolic pressure, conversely, resulted not significantly different in the two groups. The renal function was assessed by measuring the urinary output (V) and creatinine clearance (CrCl). During the first 24 hours, both parameters resulted more preserved in inferior than in anterior AMI (V-552 vs 214 ml; p < 0.005; CrCl 70.6 vs 33.42; p < 0.001). Thus 1) the pressure decrease resulted unrelated to the size of asynergy and 2) the markers of renal function, although the decrease in brachial pressure has been identical in the two groups, have been shown to decrease more profoundly in the anterior infarction.

This may depends upon the reflex interruption of efferent nervous sympathetic drive toward the renal arteriolar bed, occurring in inferior infarction, despite of the systemic hypotension, and able to exercising a beneficial influence on the glomerular filtration rate (GFR). This reflex modulation has been demonstrated as effective in the inferior, but not in the anterior localization of infarction, this different haemodynamic pattern being able to explain the more pronounced decrease in GFR and diuresis in anterior than inferior AMI, as observed in our study.