Angiotensin II blockade in hypertensive dialysis patients

Five hypertensive haemodialysis patients have been infused with saralisin. The infusion appears to be a simple diagnostic test separating patients into two groups. First, there are those whose blood pressure does not fall with saralasin pre-dialysis, but does fall with weight removal during dialysis; the blood pressure in these patients can be controlled by a reduction in pre-dialysis weight. Second, there are those whose blood pressure does fall with saralasin either pre- or post-dialysis; their arterial pressure does not fall with weight removal, but can be controlled by anti-hypertensive drugs. In two of the patients who responded to saralasin, the mechanism of the high blood pressure appeared to change from volume dependency, partial or complete, with suppressed renin release, to angiotensin dependency, partial or complete, as weight was removed during dialysis. These patients illustrate the importance of the interaction between volume and the level of angiotensin II in the maintenance of hypertension.