Renal Considerations in Angiotensin Converting Enzyme Inhibitor Therapy : A Statement for Healthcare Professionals From the Council on the Kidney in Cardiovascular Disease and the Council for High Blood Pressure Research of the American Heart Association

Stratum 2 of the Ramipril Efficacy in Nephropathy (REIN) study has already shown that in patients with chronic nephropathies and proteinuria of 3 g or more per 24 h, angiotensin-converting enzyme (ACE) inhibition reduced the rate of decline in glomerular filtration and halved the combined risk of doubling of serum creatinine or end-stage renal failure (ESRF) found in controls on placebo plus conventional antihypertensives. In REIN stratum 1, reported here, 24 h proteinuria was 1 g or more but less than 3 g per 24 h. In stratum 1 of this double-blind trial 186 patients were randomised to a ramipril or a control (placebo plus conventional antihypertensive therapy) group targeted at achieving a diastolic blood pressure of less than 90 mm Hg. The primary endpoints were change in glomerular filtration rate (GFR) and time to ESRF or overt proteinuria (> or =53 g/24 h). Median follow-up was 31 months. The decline in GFR per month was not significantly different (ramipril 0.26 [SE 0.05] mL per min per 1.73m2, control 0.29 [0.06]). Progression to ESRF was significantly less common in the ramipril group (9/99 vs 18/87) for a relative risk (RR) of 2.72 (95% CI 1.22-6.08); so was progression to overt proteinuria (15/99 vs 27/87, RR 2.40 [1.27-4.52]). Patients with a baseline GFR of 45 mL/min/1.73 m2 or less and proteinuria of 1.5 g/24 h or more had more rapid progression and gained the most from ramipril treatment. Proteinuria decreased by 13% in the ramipril group and increased by 15% in the controls. Cardiovascular events were similar. As expected, the rate of decline in GFR and the frequency of ESRF were much lower in stratum 1 than they had been in stratum 2. In non-diabetic nephropathies, ACE inhibition confers renoprotection even to patients with non-nephrotic proteinuria.

The present analysis examines the prognostic implications of moderate renal insufficiency in patients with asymptomatic and symptomatic left ventricular systolic dysfunction. Chronic elevations in intracardiac filling pressures may lead to progressive ventricular dilation and heart failure progression. The ability to maintain fluid balance and prevent increased intracardiac filling pressures is critically dependent on the adequacy of renal function. This is a retrospective analysis of the Studies of Left Ventricular Dysfunction (SOLVD) Trials, in which moderate renal insufficiency is defined as a baseline creatinine clearance <60 ml/min, as estimated from the Cockroft-Gault equation. In the SOLVD Prevention Trial, multivariate analyses demonstrated moderate renal insufficiency to be associated with an increased risk for all-cause mortality (Relative Risk [RR] 1.41; p = 0.001), largely explained by an increased risk for pump-failure death (RR 1.68; p = 0.007) and the combined end point death or hospitalization for heart failure (RR 1.33; p = 0.001). Likewise, in the Treatment Trial, multivariate analyses demonstrated moderate renal insufficiency to be associated with an increased risk for all-cause mortality (RR 1.41; p = 0.001), also largely explained by an increased risk for pump-failure death (RR 1.49; p = 0.007) and the combined end point death or hospitalization for heart failure (RR 1.45; p = 0.001). Even moderate degrees of renal insufficiency are independently associated with an increased risk for all-cause mortality in patients with heart failure, largely explained by an increased risk of heart failure progression. These data suggest that, rather than simply being a marker of the severity of underlying disease, the adequacy of renal function may be a primary determinant of compensation in patients with heart failure, and therapy capable of improving renal function may delay disease progression.

Although the prevalence of nephrotoxicity in patients treated with nonsteroidal anti-inflammatory drugs (NSAIDs) is relatively low, the extensive use profile of these agents implies that many persons are at risk. At basal states of normal renal function, the role of renal prostaglandin production for maintenance of stable renal hemodynamic function is relatively limited. Nonetheless, in the clinical setting of reduced renal perfusion as seen in various forms of cardio-renal disease, dehydration, and the aging kidney, the adequacy of renal prostaglandin production mediated predominantly by cyclooxygenase-1 (COX-1) and, potentially, by COX-2 enzyme activity becomes of major significance in the activation of compensatory renal hemodynamics. Inhibition of renal prostaglandin production by the use of NSAIDs in these circumstances can potentially lead to the emergence of several distinct syndromes of disturbed renal function. These include fluid and electrolyte disorders, acute renal dysfunction, nephrotic syndrome/ interstitial nephritis, and renal papillary necrosis. In addition, by blunting the homeostatic renal effects of prostaglandins, NSAIDs can adversely influence blood pressure control, particularly during the use of angiotensin-converting enzyme (ACE) inhibitors, diuretics, and beta blockers. This is a matter of considerable public health concern, in that some 12 million US citizens are concurrently treated with NSAIDs and antihypertensive drugs. Finally, the risk of congestive heart failure is significantly increased when NSAIDs are given to patients receiving diuretic therapy who have cardiovascular risk factors. Physiologic factors, clinical presentations, diagnostic modalities, and clinical management strategies appropriate to these NSAID-induced renal syndromes are described.