Microembolic Signals and Cerebrospinal Fluid Markers of Neuronal Damage After Surgical Aortic Valve Replacement
|Study Design:||Observational Model: Case-Only
Time Perspective: Prospective
|Official Title:||Microembolic Signals and Cerebrospinal Fluid Markers of Neuronal Damage After Surgical Aortic Valve|
- Transcranial Doppler(TCD) Microembolic Signals During Surgical Aortic Valve Replacement Surgery [ Time Frame: (day 1) TCD will be performed from start of surgery till end of surgery-exact time cannot be stated in advance ]Transcranial Doppler measurement of microembolic signals will be measured during the surgical procedure.Microembolic signals are detected by offline analysis of the Dopplerspectral analysis of the blood flow in the medial cerebral artery. Different intensities (dB),flow direction and time frame appearances in the Doppler spectral envelope is distinguishable for a neurosonolgist according to predefined criteria for an embolic signal-defined in previous litterature.The total amount of signals during one surgical procedure is counted. The appearance of microembolic signals related to specific procedures performed during cardiac surgery with cardiopulmonary bypass is noted. The exact time range is not possible to estimate in advance,due to the fact that each surgical procedure varies in time.The range of values for each individual patient, based on pilos, will vary from 50 to approximately 1500 embolic counts for one surgical procedure. A high value is negative for the patient.
- Cerebrospinal Fluid(CSF) Levels of S-100B(Microgram/Liter) [ Time Frame: 24 Hours after Surgery ]
Differences in preoperative vs postoperative CSF levels of S-100B in microgram/Liter
The assumption is that a cardiac open heart surgical procedure with cardiopulmonary bypass will influence the postoperative level of marker of neuronal cell damage in the central nerve system. An increase in the levels, compared to the preoperative values, indicates neuronal cell damage detectable in the CSF, namely the brains own extracellular fluid.
Biospecimen Retention: Samples Without DNA
|Study Start Date:||November 2010|
|Study Completion Date:||June 2011|
|Primary Completion Date:||June 2011 (Final data collection date for primary outcome measure)|
Surgical aortic valve replacement
Single observational study. Count of microembolic signals during open heart surgery and measurement of properative vs postoperative levels of markers in cerebrospinal fluid of neuronal damge.
Other: Open heart surgery
TCD count of microembolic signals during surgical aortic valve replacement
Patients and clinical procedures 10 patients scheduled for open aortic valve surgery at our institution will be included into this prospective, observational study. The Human Ethics Committee of the University of Gothenburg, approved the study protocol. The day before surgery a lumbar puncture at level L3-4 will be performed using a 27G Whitacre needle. A sample of 2.5 ml of cerebrospinal fluid will be taken for analysis of S-100B, NSE, Tau and albumin.
On arrival at OR, standard perioperative monitoring will be established, including an Auditory Evoked Potential (AEP) monitor for anaesthetic depth measurements (AEP Monitor/2, Danmeter, Odense, Denmark) and radial arterial and central venous lines. General anaesthesia is induced with propofol 0.5-1 mg/kg and fentanyl 10 μg/kg. Tracheal intubation will be facilitated using atracurium 0,5 mg/kg. Sevoflurane is used to maintain an anaesthetic depth adjusted to an AAI index of 15-30 as recorded by the AEP monitor. Hemodynamic stability will be obtained by the use of colloidal solution administration, guided by the use of intra-operative transesophageal echocardiography, and norephineprine to maintain a mean arterial pressure above 75 mmHg-Also during CPB. A lumbar puncture will be repeated the first postoperative day repeating the measurement of markers in CSF A certified cardiologist or anaesthesiologist assess focal neurological impairment before and within 24 hours after the procedure.
Transcranial Doppler (TCD) By TCD the right medial cerebral artery (RMCA) will be insonated by the transtemporal approach at a depth of approximately 50 mm using standard criteria. The investigators use a 2 MHz power M-mode TCD monitor (ST3 ©, Spencer Technologies Seattle, WA), with the probe fixed in position using a head frame. The Doppler signals will be continuously monitored and saved to monitor hard drive. Two physicians independently evaluate the TCD data files offline, and identify microembolic signals (MES) using criteria for counting emboli signals on spectral and PMD TCD.
Statistical Analysis: Descriptive statistics and tests of normality for continuos data Correlation analysis; Total cerebral embolic load vs. increase of CSF level S-100B/ NSE/Tau.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01319799
|Department of Thoracic Anaesthesia & Intensive Care,Sahlgrenska University Hospital|
|Gothenburg, Sweden, 41345|
|Study Director:||Sven Erik Ricksten, Professor||Sahlgrenska University Hospital,Thoracic Anesthesia & Intensive Care|