Acute kidney injury after transcatheter aortic valve implantation: Impact of contrast agents, predictive factors, and prognostic importance in 203 patients with long-term follow-up.

BACKGROUND: Acute kidney injury (AKI) frequently occurs following transcatheter aortic valve implantation (TAVI) and has been related to a worse outcome. We investigated the importance of contrast medium composition, either iso-osmolar (IOCM) or low-osmolar (LOCM) and assessed predictors for AKI after TAVI. METHODS AND RESULTS: We assessed AKI in 203 TAVI patients treated mainly with trans-femoral implantation and analgosedation. A total of 100 patients received IOCM and 103 LOCM. AKI was defined according to the Valve Academic Research Consortium. Following TAVI, 39 patients (19.2%) developed AKI; 17.0% of the IOCM and 21.4% of the LOCM group (p=0.43). The only independent predictor for AKI was baseline serum creatinine [odds ratio (OR) 0.26, 95% confidence interval (CI) 0.01-0.64, p=0.002]. Patients with advanced AKI (stages 2 and 3) post-TAVI had significantly higher mortality at 2 years (log rank p<0.001), whereas patients with AKI stage 1 had a similar long-term outcome to non-AKI patients. CONCLUSIONS: Following TAVI, we observed no difference in the occurrence of AKI between IOCM and LOCM. Baseline creatinine was the only independent predictor of AKI, and patients who developed advanced AKI had significantly higher mortality at 2 years.

Intramyocardial oxygen monitoring in coronary artery bypass surgery.

OBJECTIVE: In coronary artery bypass surgery various parameters have been used to monitor patients clinical status. Direct monitoring of myocardial oxygenation can be performed by measuring intramyocardial partial oxygen tension pressure (p ti O2). This study was performed to determine the perioperative time course of this parameter in correlation to standard monitoring parameters. METHODS: Twenty-three patients underwent standard coronary artery bypass grafting (CABG). A special polarographic microprobes was inserted into the myocardium in the distribution zone of the left anterior descending artery which was one of the target vessels of myocardial revascularization. Intramyocardial p ti O2 was monitored intra- and up to 12 hours postoperatively. Values were correlated to hemodynamic, oxygenation and procedure associated parameters. RESULTS: Myocardial oxygenation during CABG is characterized by a significant decrease of p ti O2 during cross-clamping and a significant increase after removal of the cross-clamp. The postoperative time course of p ti O2 shows a steady increase of p ti O2 in the first 12 postoperative hours investigated. Preoperative ejection fraction as well as cardio-pulmonary bypass time does not seem to have an influence on the postoperative p ti O2 in these patients. Various standard monitoring parameters show complex influence on intramyocardial p ti O2- CONCLUSIONS: Determination of intramyocardial partial oxygen pressure in patients undergoing bypass surgery shows characteristic changes. Changes in p ti O2 as a direct online parameter of myocardial oxygenation occur immediately after procedures that influence myocardial perfusion and therefore, may help to detect potential complications earlier than standard monitoring parameters in cardiac surgery.

Intramyocardial partial oxygen pressure in patients undergoing transmyocardial laser revascularization and bypass surgery.

OBJECTIVE: Numerous investigations could not clarify the exact mechanism of transmyocardial laser revascularization (TMLR). The aim of this study was to investigate, whether TMLR leads to an increase of myocardial oxygenation in comparison to patients undergoing coronary artery bypass grafting (CABG). DESIGN: Twelve patients (TMLR group) underwent TMLR alone with an 800 W CO2 laser through a left anterior thoracotomy. Seventeen patients (CABG group) underwent standard CABG. Myocardial oxygenation was determined by measuring intramyocardial partial oxygen pressure (ptiO2 ). PtiO2 was measured online and mean values at 1, 24, 32, and 48 h postoperatively were compared with baseline before intervention. Parameters influencing ptiO2 (arterial pO2, hemodynamic parameters, hemoglobin) were recorded. RESULTS: Mean baseline ptiO2 was significantly lower in the TMLR group compared with the CABG group (p < 0.05). In both groups ptiO2 increased significantly in the postoperative course, whereby ptiO2 in the TMLR group was significantly lower compared with the CABG group. CONCLUSION: Although the exact mechanism of action of TMLR remains unclear, ptiO2 and thus oxygen supply in the myocardium increased in patients undergoing TMLR at least in the early postoperative course. However, ptiO2 increased to a lesser extent compared with CABG.