Use of NaCl saline hydration and N-Acetyl Cysteine to prevent contrast induced nephropathy in different populations of patients at high and low risk undergoing coronary artery angiography.

AIM: Contrast-induced nephropathy (CIN) is most commonly defined as acute renal failure occurring within 48-72 h of exposure to intravascular radiographic contrast medium that is not attributable to other causes. In international literature a 25% increase in serum creatinine levels or an increase in absolute values of 0.5 mg/dL from baseline has been suggested to define CIN. The reported incidence of CIN varies widely, ranging from 2% to 50%. This variability results from differences in the presence or absence of risk factors. With a retrospective analysis authors evaluated the use of NaCl saline hydration and N-acetyl cysteine (NAC) to prevent CIN in different populations of patients at high and low risk undergoing coronary artery angiography. METHODS: From January 2007 to December 2008, 597 patients underwent coronary artery angiography with a low osmolarity contrast agent. Nephrotoxic drugs such as diuretics, metformin, ACE-I and ARBs were stopped at least 24 h before the procedure. The population was divided into two groups: group A (high risk 342 patients, 57.2%) identified for the presence of at least one risk factor such as diabetes, age >65 years, baseline creatinine >1.4 mg/dL and group B (low risk 255 patients, 42.8%) for the absence of any of the risk mentioned above. Only group A was treated with a saline hydration (1 mL/kg/h) plus NAC 600 mg 12 h before and 12 h after the procedure. RESULTS: The overall incidence of CIN was 6.7% (40 patients). In particular, the incidence of CIN was 4.4% (15 patients) in the group A and 9.8% (25 patients) in the group B respectively (P=0.017). Interestingly, the Contrast Index (volume administrated/theoretical maximum volume) was significantly lower in group B (P<0.005). In the multivariate analysis, including risk factors such as age, diabetes, hypertension, hypercholesterol-mia, current smoke, baseline creatinine level, Contrast Index and hydration, the last variable was the only one inversely correlated independently with the incidence of CIN (P=0.001). CONCLUSIONS: The hydration with saline and NAC is an effective and low-cost tool in preventing CIN in patients undergoing coronary artery angiography and, according to the current guidelines, should be used in all high-risk patients. Present results show that even in patients at low risk for CIN, hydration could be useful: in fact, despite the Contrast Index was significantly lower in this population, the incidence of CIN was greater, thus suggesting a potential role for hydration also in the low-risk population.

Left atrial myocardial function in either physiological or pathological left ventricular hypertrophy: a two-dimensional speckle strain study.

BACKGROUND: Atrial function is an integral part of cardiac function that is often neglected. The presence of left ventricule hypertrophy (LVH) due to arterial hypertension may impair atrial function. However, it has also been suggested that physical training attenuates the age-associated impairment of diastolic filling. This study investigated whether mechanical dysfunction in the left atrium (LA) is present in patients with either physiological or pathological LVH, using two-dimensional strain rate imaging (2D strain echocardiography; 2DSE). METHODS: Standard echocardiography, exercise stress echo and 2DSE of the left atrium were performed in 40 patients with arterial hypertension, 45 age-matched elite athletes (>40 years) and 25 healthy sedentary controls. Atrial longitudinal strain was performed from the apical views for the basal segments of the LA septum, lateral wall and roof. RESULTS: LV mass index and ejection fraction were comparable between patients with either physiological or pathological LVH. Elite athletes showed increased LV end-diastolic diameter, end-diastolic volume and stroke volume, whereas circumferential end-systolic stress was higher in patients with hypertension. LA diameter and maximum volume were increased but similar between the two groups of patients with LVH. LA active emptying volume and fraction were both higher in patients with hypertension. Conversely, peak systolic myocardial atrial strain was significantly reduced in patients with pathological LVH compared with controls and athletes for all the analysed atrial segments (p<0.0001). Using multivariate analysis, LV end-diastolic volume/body surface area (BSA) (beta coefficient 0.52; p<0.0001) and LV mass (beta = 0.48; p<0.001) in athletes emerged as the only independent determinants of LA lateral wall peak systolic strain. In contrast, in patients with hypertension, an independent negative association of LA lateral wall peak systolic strain with both LV mass (beta = -0.42; p<0.001) and circumferential end-systolic stress (beta = -0.43; p<0.001) was found. In addition, in the overall population of patients with LVH, LA lateral wall systolic strain (beta = 0.49; p<0.0001) was a powerful independent predictor of maximum workload during exercise testing. CONCLUSIONS: 2DSE represents a promising, non-invasive, simple and reproducible technique to assess LA myocardial function in patients with either physiological or pathological LVH. LA myocardial deformation is impaired in patients with hypertension compared with age-matched sedentary controls and elite athletes, and is closely associated with functional capacity during effort.