Regional and systemic haemodynamic response to aortography in hypertensives

Objective To study the effects of aortography and of aortic counterflow bol us injection per se on regional and systemic haemodynamics in hypertensives in comparison to normotensive matched controls. Design and methods Mean blood velocity (MBV) and pulsatility index (PI) - a s an index of regional vascular resistance - by the Doppler technique, at t he femoral, common carotid and brachial arteries, finger arterial pressure and electrocardiographic R-R' interval were monitored beat-by-beat, before, during and for 3 min following counterflow bolus injections into the abdom inal aorta of 40 ml/2.6 s of iopamidol (I), iso-osmolar mannitol (M) and 0. 9 N saline (S), in 11 hypertensive and nine normotensive patients. Results After bolus injection of iopamidol, MBV increased to a peak at 35 /- 5 s, both in normotensive (Delta MBV versus baseline +16.7 a 9.9 cm/s; P < 0.01) and in hypertensive subjects (Delta MBV versus baseline: +13.9 a 6 .6 cm/s; P < 0.01). At the same time, the PI decreased both in normotensive (Delta PI versus baseline: -4.05 +/- 2.49; P < 0.01) and in hypertensive s ubjects (Delta PI versus baseline: -3.02 +/- 2.25; P< 0.01). After M boluse s, the haemodynamic changes were of the same direction and magnitude as I f or both groups, while after S the magnitude was approximately 50% lower. No significant differences were observed between normotensive and hypertensiv e subjects. In other vascular circulations, a 15% increase of the early dia stolic backflow in the brachial artery, in phase with the femoral artery ha emodynamic changes, was the only evidence of the procedure. Mean arterial p ressure decreased and heart rate increased in phase with flow changes of th e femoral artery. Conclusions (1) The regional flow and systemic pressure changes observed du ring aortography seem, at least partially, to be due to the hydrodynamic pe rturbation induced by bolus injection per se. (2) The physical and chemical properties of the contrast media and therefore the probable different shea r-stress modifications induced by the fluid injected could explain why the haemodynamic changes were greater after I compared to S and were more simil ar to M. (3) Hypertensive subjects did not show a different vasoreactive re sponse in comparison to normotensive subjects during aortography. (C) Lippi ncott Williams & Wilkins.