Time course changes of cystatin C and inflammatory and biochemical markers in non-ST-elevation acute coronary syndromes.

BACKGROUND: Serum cystatin C (Cys-C), a good marker of renal function, predicts prognosis in non-ST-elevation acute coronary syndromes (NSTE-ACS). However, no data are available on the time course of Cys-C values after discharge. In this study, Cys-C was measured during admission (ACS sample) and 6 weeks after discharge, and was correlated with troponin (c-TNT), high-sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6) and the N-terminal portion of the pro-brain natriuretic peptide (proBNP) peptide (NT-proBNP) in a highly selected homogeneous group of NSTE-ACS patients. METHODS: In this prospective, multicentre study, patients with a first NSTE-ACS, single-vessel disease and successful percutaneous coronary interventions (PCIs) had their sera collected, aliquoted and stored at the enrolling site and then shipped for analysis to the clinical chemistry core laboratory. RESULTS: Cys-C values slightly, but significantly, increased from the ACS samples to the 6-week samples. In contrast, hsCRP, NT-proBNP and IL-6 values significantly decreased from the ACS to the 6-week sample. Patients with elevated c-TNT levels had higher hsCRP, NT-proBNP and IL-6 values than patients with normal c-TNT levels in the ACS sample, whereas Cys-C levels were similar in patients with and without elevated c-TNT. Cys-C was highly correlated with estimated glomerular filtration rate in both the ACS and 6-week samples. CONCLUSIONS: In contrast to inflammatory and biochemical stress markers, Cys-C is not affected by the occurrence of myocardial necrosis or by acute left-ventricular impairment, being a reliable marker of renal function during NSTE-ACS.

Intracoronary ST segment evolution during primary coronary stenting predicts infarct zone recovery.

In patients with acute myocardial infarction (AMI), early ST segment elevation resolution on ECG predicts myocardial reperfusion and LV recovery. Intracoronary ECG is more sensitive than surface ECG to detect regional ischemia. In patients undergoing primary percutaneous coronary intervention (PCI), we investigated if failed myocardial reperfusion, despite successful infarct vessel recanalization, could be rapidly and easily identified by intracoronary ST segment monitoring from guidewire recording. We recorded intracoronary and standard ECG during primary coronary stenting (PCI) in 50 patients with AMI (59 +/- 11 years; anterior AMI in 66%). All patients had a successful PCI and underwent 2D echocardiography soon after PCI and 6 months later. Following PCI, intracoronary ST resolution >/= 50% from baseline was documented in 39 patients (78%; group A; from 11 +/- 8 to 1 +/- 2 mm) but not in 11 (22%; group B; from 11 +/- 8 to 8 +/- 5 mm). Group A had slightly shorter ischemic time (202 +/- 94 vs. 238 +/- 112 min in B; P = 0.2) and smaller peak CK values (2,752 +/- 2,038 vs. 4,802 +/- 3,671 U/L in B; P = 0.02). After PCI, ST resolution was found on standard ECG in 34 (87%) group A and in 3 (27%) group B patients. At 6-month follow-up, left ventricular ejection fraction was greater in group A (47% +/- 8% vs. 39% +/- 8% in B; P < 0.001) with improved wall motion score index (from 2.2 +/- 0.3 to 1.7 +/- 0.3 in A; from 2.3 +/- 0.4 to 2.1 +/- 0.4 in B; P < 0.001). There were no significant differences between intracoronary and standard ECG for sensitivity (92% vs. 86%) and specificity (62% vs. 57%) to predict improved infarct zone recovery after 6 months. ST elevation resolution on intracoronary recording during PCI predicts infarct zone recovery. Monitoring ST segment evolution by intracoronary ECG allows prompt and inexpensive identification in the catheterization laboratory of those patients without myocardial reperfusion, who may require adjunctive therapeutic interventions after successful infarct vessel recanalization.