Rapid Effects of a Single High Dose of Simvastatin on C-Reactive Protein in Patients with Unstable Angina

Changes of plasma inflammatory markers after withdrawal of statin therapy in patients with hyperlipidemia

BACKGROUND

Atherosclerosis has been considered to be an inflammatory process. In addition to its lipid-lowering properties, statin has been shown to decrease the concentrations of inflammatory markers resulting in reduction of cardiovascular events. Emerging data suggest that withdrawal of statin might be associated with increased cardiac events. The mechanism for this phenomenon, however, is still unclear. We investigated whether acute termination of statin treatment could result in rebound of inflammatory markers, such as C-reactive protein (CRP) and interleukin-6 (IL-6), in patients with hyperlipidemia.

METHODS

Seventeen patients (11 men and 6 women, mean age 51+/-7 years) with hyperlipidemia were given 40 mg/day of pravastatin for 6 weeks. The concentrations of plasma CRP and IL-6 were evaluated before receiving the statin therapy, immediately after 6 weeks of pravastatin therapy, and at days 1, 3 and 7 after withdrawal of pravastatin therapy. The lipid profile was also evaluated at baseline, 6 weeks of therapy, and at day 7 after terminating pravastatin.

RESULTS

Pravastatin therapy induced significant reductions in total cholesterol (TC, 6.88+/-0.36 vs. 5.27+/-0.23 mmol/l, p<0.01), low-density lipoprotein (LDL) cholesterol (4.28+/-0.25 vs. 3.06+/-0.14 mmol/l, p<0.01), CRP (0.28+/-0.16 vs. 0.20+/-0.08 mg/l, p<0.01), and IL-6 (8.4+/-0.6 vs. 6.7+/-0.4 pg/dl, p<0.01). Although the TC and LDL-cholesterol did not change during the 7-day period after withdrawal of pravastatin therapy, the concentrations of CRP and IL-6 increased at day 3 (CRP: 0.20+/-0.08 vs. 0.27+/-0.12 mg/l, and IL-6: 6.7+/-0.4 vs. 7.7+/-0.6 pg/dl, p<0.05 respectively) and at day 7 (CRP: 0.20+/-0.08 vs. 0.30+/-0.14 mg/l, and IL-6: 6.7+/-0.4 vs. 8.7+/-0.8 pg/dl, p<0.01 respectively) after withdrawal of pravastatin therapy. No correlation between increase of CRP as well as IL-6 and small changes of LDL-cholesterol concentrations was found after withdrawal of pravastatin therapy at day 7 (r=-0.021 and r=-0.044 respectively, p>0.05 respectively).

CONCLUSIONS

6 weeks after pravastatin therapy could significant modify the lipid profile and decrease the inflammatory markers including CRP and IL-6 in patients with hyperlididemia. Moreover, statin therapy discontinuation could induce a rebound phenomenon of inflammatory response representing an increase in some inflammatory markers, which is independent of changes of lipid parameters.

Rebound phenomenon of inflammatory response may be a major mechanism responsible for increased cardiovascular events after abrupt cessation of statin therapy

Inflammation has been recognized as having an important role in the development and progression of atherosclerosis. Statins reduce cardiovascular events mainly by cholesterol lowering. A large number of investigations have demonstrated that administration of statin could modify inflammatory response with a concurrent fall in cardiovascular events. Despite the known benefit of statin therapy, many cardiac patients abruptly discontinue therapy because of financial constraints, forgetfulness, or side effects. More recently, several studies have shown that abrupt cessation of statin therapy during treatment could increase the incidence of cardiac events in patients with atherosclerotic heart disease. However, the mechanisms of the increased incidence of cardiovascular events after abruptly stopping statin therapy are still unknown. A few data suggest that abrupt withdrawal of statin therapy deteriorates endothelial function, result in expression of pro-inflammatory gene involved in the development and progression of atherosclerosis. We hypothesis that rebound phenomenon of inflammatory response may be a major mechanism responsible for increased cardiovascular events after abrupt cessation of statin therapy. Our very recent data showed that abrupt termination of statin therapy resulted in a rapid increased C-reactive protein (CRP) and interleukin-6 (IL-6) levels in patients with hypercholesterolemia. This finding may be of important interest in the connection between inflammatory response and abrupt withdrawal of statin therapy in patients with coronary artery disease.

Inflammation: a possible pathogenic link to cardiac syndrome X

Cardiac syndrome X is defined as a typical angina pectoris, positive treadmill exercise test, negative intravenous ergonovine test and normal coronary angiography. The pathogenesis of cardiac syndrome X has previously ascribed to myocardial ischemia that may be caused by microvascular dysfunction and increased sensitivity to intracardiac pain. Despite the extensive studies, the pathophysiological mechanisms in cardiac syndrome, however, remain unclear. More recently, the data has been suggested that chronic inflammation has been associated with cardiac syndrome X. The evidence for the hypotheses included that inflammatory marker are increased, and associated with the disease activity in patients with cardiac syndrome X. And also, statin, a lipid-lowering as well as anti-inflammatory drug, has significantly modified the disease process in this special syndrome. Despite the good prognosis of cardiac syndrome X, the chronic, frequent nature of the persistent angina and reduced exercise tolerance can significantly impair quality of life. Thus, lowering inflammatory response by, for example, use of statin and/or aspirin, might improve coronary microvascular dysfunction. Whether this is a valid approach, however, is still unknown and deserves further investigation. Indeed, as mediators of inflammation are multiple, the strategy of identifying triggers and mechanisms of inflammation in each special clinical setting and directing treatment at the special triggers or to rate limiting steps in effector pathways appears more reasonable or a promising strategy.