Timely extracorporeal membrane oxygenation assist reduces mortality after bypass surgery in patients with acute myocardial infarction.

BACKGROUND: Patients with acute myocardial infarction (AMI) are at high risk when undergoing emergency coronary artery bypass graft (CABG)-surgery. Their outcome remains poor despite increased use of extracorporeal membrane oxygenation (ECMO). We investigated the impact of timing for perioperative ECMO-support in these patients. METHODS: In this retrospective double-center study, we evaluated 201 patients with AMI undergoing CABG, dividing them into the following groups: No-ECMO (n = 101), preoperative ECMO (pre-ECMO, n = 6), intraoperative ECMO (ECC-ECMO, n = 67), and postoperative ECMO (post-ECMO, n = 27). We evaluated the impact of ECMO timing on postoperative mortality, organ function, and length of stay, comparing these to predicted outcome using different risk-scores. RESULTS: Post-ECMO patients showed lowest 30-day-survival (40.7%), while earlier ECMO-start was associated with better outcome (50.7% in extracorporeal circulation [ECC]-ECMO and 66.7% in pre-ECMO patients). On admission, only pre-ECMO and ECC-ECMO patients showed higher surgery- and intensive-care-unit (ICU)-related risk-scores. In pre- and ECC-ECMO patients, the first significant increase in lactate-levels (>4 mmol/L) was observed preoperatively, while this occurred 1 hour postoperatively in post-ECMO patients. Bilirubin was increased in all patients, decreasing after 3 and 12 days in pre- and ECC-ECMO patients, respectively, but only after 18 days in post-ECMO patients. Multiple ICU risk-scores did not discriminate survival-probability correctly. Only the ECMO-related survival after veno-arterial-ECMO-score correctly predicted the significantly lower survival in post-ECMO patients. CONCLUSION: Our study shows that timely ECMO-support is associated with earlier bilirubin-downtrend and higher survival in patients with AMI after CABG. Lactate-increase greater than 4 mmol/L seems to be a helpful threshold to trigger the timely onset of ECMO-therapy, providing better survival.

Patency and in vivo compatibility of bacterial nanocellulose grafts as small-diameter vascular substitute.

OBJECTIVE: Despite the clinical success of large-diameter vascular grafts, synthetic grafts in small-diameter vessels are of limited use because of their poor patency rates. Previous experiments of our group provided evidence for good biocompatibility of bacterial nanocellulose (BNC) as a small-vessel graft in the carotid artery in sheep. However, the patency rate of our first-generation tubes after 3 months was only 50%. To advance our concept, we now used modified second-generation tubes with diminished wall thickness and a smoother inner surface to reduce the thrombogenic potential. The aim was to investigate mechanical characteristics of modified second-generation BNC tubes, to evaluate in vivo performance and biocompatibility, and to analyze patency rates. METHODS: We replaced the right carotid artery of 23 sheep with second-generation BNC tubes. Compared with our first-generation tubes, tubes were modified with different surface properties and diminished wall thickness (inner diameter, 4.0-5.0 mm; wall thickness, 1.0-2.5 mm; length, 100 mm) to generate a smoother inner surface with reduced thrombogenic potential and a more porous outer zone, allowing easier cell immigration. RESULTS: At the end of the investigational period, BNC tubes were explanted and grafts were processed for histopathologic analysis. Histologic analysis revealed no acute signs of foreign body reaction such as immigration of giant cells or other acute inflammatory reaction and therefore provided evidence for good biocompatibility of the second-generation tubes. However, all grafts of the sheep without antiplatelet therapy were occluded after 9 months, whereas grafts in sheep receiving dual platelet inhibition showed a patency rate of 67% (six of nine grafts). Further modified grafts revealed a patency rate of 80% (four of five grafts remained open). CONCLUSIONS: Patency rates of the second-generation tubes could be substantially improved compared with our first-generation tubes. However, poor patency rates of tissue-engineered blood vessels still limit their use in clinical studies. Further efforts in terms of in vitro and in vivo studies are essential to improve grafts of BNC.

Utility of NT-pro-BNP in patients undergoing transapical aortic valve replacement.

BACKGROUND: Transapical aortic valve replacement (TAVR) is increasingly being applied in conventionally inoperable patients with aortic stenosis. The utility of the cardiac marker NT-pro-BNP has yet not been assessed in this setting. METHODS: NT-pro-BNP was assessed preoperatively, postoperatively (day 1, 3, 5 and 8) and 2 months after the intervention in 31 consecutive patients (13 men, 18 women; median age 84) undergoing TAVR and the association with baseline characteristics and outcome was analysed. RESULTS: Baseline NT-pro-BNP was associated with baseline creatinine, left-ventricular mass index and NYHA class and predicted regression of LV-mass after 2 months. There was no correlation of NT-pro-BNP with measures of the aortic valve function before or after replacement. The increase of NT-pro-BNP 3 days after TAVR was inversely associated with a functional improvement of >or=1 NYHA class at 2 months. Baseline NT-pro-BNP was not associated with 2-month mortality and major adverse events (death/neurological deficit), whereas the postoperative increase of NT-pro-BNP after TAVR showed a slightly significant inverse and the EuroSCORE a significant correlation. CONCLUSIONS: In multimorbid patients undergoing TAVR, NT-pro-BNP independently predicted regression of LV-mass after 2 months and early decrease of NT-pro-BNP postoperatively indicated improvement of functional capacity at 2 months. There was no association of NT-pro-BNP with 2-month mortality.