Multidose Cardioplegia in Adult Cardiac Surgery

Cerebral microemboli have been associated with neurocognitive deficits after cardiac operations using cardiopulmonary bypass (CPB). Interventions by the perfusionist and alterations in blood flow account for a large proportion of previously unexplained microemboli. This study compared the incidence of microemboli during cardiac operations using conventional (multidose) and del Nido (single-dose) cardioplegia delivery. Transcranial Doppler ultrasonography was used to detect microemboli in bilateral middle cerebral arteries of 30 adult patients undergoing cardiac operations using CPB and aortic clamping. Multidose conventional blood cardioplegia (CBC) was used in 15 patients and single-dose del Nido cardioplegia (DNC) in 15. Manual count of microemboli during cross-clamp and during administration of cardioplegia was performed. Baseline preoperative characteristics were similar between groups. There were no differences in the ascending aortic atheroma grade (1.4 ± .4 CBC vs. 1.6 ± .7 DNC, p = .44), bypass times (141 ± 36 minutes CBC vs. 151 ± 33 minutes DNC, p = .64), and cross-clamp times (118 ± 32 minutes CBC vs. 119 ± 45 minutes DNC, p = .95). The use of multidose CBC was associated with a seven-fold increase in the number of microemboli per minute of bypass (1.65 ± 1 vs. .24 ± .18 emboli/min DNC, p = .0004). In this prospective pilot study, we found that the use of single-dose cardioplegia strategy led to fewer cerebral microemboli when compared with the traditional multidose approach. Our findings warrant further investigation of various cardioplegia strategies and neurologic outcomes in larger cohorts.

Increased endothelial activation in recently symptomatic versus asymptomatic carotid artery stenosis and in cerebral microembolic-signal-negative patient subgroups

BACKGROUND AND PURPOSE

von Willebrand factor propeptide (VWF:Ag II) is potentially a more sensitive marker of acute endothelial activation than von Willebrand factor antigen (VWF:Ag). These biomarkers have not been simultaneously assessed in asymptomatic versus symptomatic carotid stenosis patients. The relationship between endothelial activation and cerebral microembolic signals (MESs) detected on transcranial Doppler ultrasound is unknown.

METHODS

In this multicentre observational analytical study, plasma VWF:Ag and VWF:Ag II levels in patients with ≥50% asymptomatic carotid stenosis were compared with those from patients with ≥50% symptomatic carotid stenosis in the 'early' (≤4 weeks) and 'late' (≥3 months) phases after transient ischaemic attack or ischaemic stroke. Endothelial activation was also longitudinally assessed in symptomatic patients during follow-up. Transcranial Doppler ultrasound monitoring classified patients as MES-positive or MES-negative.

RESULTS

Data from 31 asymptomatic patients were compared with those from 46 early symptomatic and 35 late phase symptomatic carotid stenosis patients, 23 of whom had undergone carotid intervention. VWF:Ag II levels were higher in early (12.8 μg/ml; P < 0.001), late (10.6 μg/ml; P = 0.01) and late post-intervention (10.6 μg/ml; P = 0.038) symptomatic patients than asymptomatic patients (8.9 μg/ml). VWF:Ag levels decreased in symptomatic patients followed up from the early to late phase after symptom onset (P = 0.048). Early symptomatic MES-negative patients had higher VWF: Ag II levels (13.3 vs. 9.0 μg/ml; P < 0.001) than asymptomatic MES-negative patients.

CONCLUSIONS

Endothelial activation is enhanced in symptomatic versus asymptomatic carotid stenosis patients, in early symptomatic versus asymptomatic MES-negative patients, and decreases over time in symptomatic patients. VWF:Ag II levels are a more sensitive marker of endothelial activation than VWF:Ag levels in carotid stenosis. The potential value of endothelial biomarkers and concurrent cerebral MES detection at predicting stroke risk in carotid stenosis warrants further study.