Follow-Up Studies
Follow-up studies by Dr. Steen and others proved that ACE inhibitors were a lifesaving intervention. Dr. Steen et al. reported on the experience of 108 patients who had scleroderma renal crisis between 1972 and 1985. The one-year survival after scleroderma renal crisis was 76% in patients who had taken ACE inhibitors and only 15% in those who had not.11 Though some patients still died and other required permanent dialysis, renal crisis could usually be effectively managed when treated early and aggressively with ACE inhibitors. More than half of the patients who initially required dialysis were able to come off it if they continued taking ACE inhibitors while their kidneys healed.
Currently, early intervention with ACE inhibitors is the standard of care at first sign of scleroderma renal crisis. However, other applications of ACE inhibitors in scleroderma patients are not as clear. Researchers also explored the role of these drugs as agents to prevent scleroderma renal crisis. By this time, ACE inhibitors were already being prescribed as a preventative for diabetic kidney disease.
However, some studies suggested that ACE inhibitors used as a preventative for scleroderma renal crisis might worsen outcomes, particularly if given to patients with normal blood pressure.12 This created some confusion in the field.
Some researchers expressed concern that ACE inhibitors might mask hypertension and lead to delayed diagnosis of renal crisis.13 Dr. Steen speculates that the chronic administration of an ACE inhibitor might have changed the disease course in some of these patients. She says, “They were presenting with creatinines that were 3 and 4 instead of 1 or 2, and by that time they already had chronic kidney disease.”
Some practitioners still prescribe ACE inhibitors as first-line agents for managing essential hypertension in scleroderma patients if they are not in a high-risk group. In contrast, Dr. Whitman notes, “As a rule of thumb, we don’t give diuretics to scleroderma patients unless we are forced to—for example, if they have heart failure—because you could theoretically trigger the renin-angiotensin system and scleroderma renal crisis.” He adds that he might start a patient out on calcium channel blocker, which are particularly good for Raynaud’s symptoms. “But if the blood pressure kept going up, we might give them an ACE inhibitor or an [angiotensin II receptor blocker].”
Scientists still have questions about renal disease in settings other than scleroderma renal crisis. Some patients have essential hypertension unrelated to scleroderma, or they have renal disease from other medical conditions. Additionally, many patients with scleroderma have subtle renal abnormalities, such as proteinuria and involvement of renal vessels, though these changes seem not to predict the development of scleroderma renal crisis.12 Dr. Steen points out that although some might develop mild renal insufficiency, very few patients go on to develop renal failure unless they experience a true scleroderma renal crisis.
