onsteroidal anti-inflammatory drugs (NSAIDs) have been associated with fluid retention and the onset of CHF in several publications (61–66). Congestive heart failure which is induced or exacerbated by NSAIDs is not mediated by a direct myocardial depressant effect of NSAIDs. The major mechanism of action of NSAIDs is the interference with prostaglandin (PG) biosynthesis by inhibiting the function of the enzyme cyclooxygenase (COX) (67). Furthermore, NSAIDs also interfere with the effects of diuretics and angiotensin-converting enzyme inhibitors (68–70). In healthy individuals, PGs play a negligible role in maintaining renal blood flow and consequently, NSAIDs usually exert no significant effects on renal hemodynamics (71,72). In patients with an impaired left ventricular function, however, PGs play an important role in the maintenance of cardiovascular and renal homeostasis. Prostaglandins have a vasodilatory effect on the afferent arteriole, oppose the effects of angiotensin II on the systemic circulation and decrease total body sodium and water. These effects of PGs are considered to contribute significantly to the maintenance of compensated heart failure in patients with impaired left ventricular function. In these patients, NSAIDs may interfere with cardiovascular homeostasis and may induce or exacerbate CHF (73).
Two isoforms of COX have been identified, COX-1 and COX-2. Cyclooxygenase-2 is predominantly involved in all stages of the inflammatory response, whereas COX-1 is mainly responsible for the synthesis of prostaglandin E2 (PGE2) and PGI2 in kidney and stomach (67). To prevent the potentially adverse effects on renal function, so-called renal-sparing NSAIDs have been introduced, such as sulindac, nabumetone and meloxicam. These agents have been reported to exert less adverse effects on renal function (74–78). However, comprehensive data on the effects of these agents on renal function and cardiovascular homeostasis in patients with decreased left ventricular function are not yet available.