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S K Braekken

Publications and source records attributed to S K Braekken.

6 recordsLinked to original sources
PubMed1998

Influence of guidewire and catheter type on the frequency of cerebral microembolic signals during left heart catheterization.

Cerebral embolization is a serious complication during diagnostic heart catheterization. To date there have been no studies to determine whether the technique and the catheter type influence the frequency of cerebral microembolic signals (MES's) during left ventricular catheterization. Twenty-two patients had a leading straight tip guidewire protruding 5 to 10 cm outside the coronary catheters when the latter was advanced over the aortic arch (group A), whereas in 21 patients the guidewire was withdrawn in the descending part of the aorta (group B). Transcranial Doppler of the left middle cerebral artery was performed to monitor the number of cerebral MES's. When a protruding guidewire was used to advance the coronary catheters over the aortic arch, MES's were detected in 86% of the patients compared with 29% when the catheters were advanced without a guidewire (relative risk = 4.6, p = 0.00001). The number of MES's per patient also was significantly higher when a guidewire was used (median 9 vs 0) (p = 0.000004). In group A, a higher number of MES's was detected when a right Judkins catheter was advanced over the aortic arch than when a left Judkins catheter was advanced (median 6.5 vs 1) (p = 0.0005) and in patients who previously had a myocardial infarction than in those who had not (median 1 1 vs 4) (p = 0.007). This study strongly suggests that the risk of embolization is greater when straight tip guidewires are used to advance catheters over the aortic arch during left ventricular heart catheterization, especially in patients with a history of myocardial infarction.

Adult↗
PubMed1998

[Cerebral microembolism detected by transcranial Doppler ultrasonography].

The clinical diagnosis of brain embolism has traditionally been based on evidence suggesting a potential embolic source. However, it is now possible to detect circulating cerebral microemboli by means of transcranial Doppler ultrasound. We explain the theory behind microembolus detection, and discuss initial clinical experience of this method. During invasive cardiovascular investigations and surgery this method can warn the physician that microemboli are entering the cerebral circulation, and preventive measures can be taken. Cerebral microemboli are quite often detected in stroke prone patients, and their presence probably indicates increased risk of stroke. In the acute phase of ischemic stroke, microembolus detection may help to decide the etiology and the source of the emboli. When microemboli are detected in cases of acute embolic stroke, serial detections can be performed which, in future studies, might be of help when evaluating the effect of the treatment.

Humans↗
PubMed1998

Association between intraoperative cerebral microembolic signals and postoperative neuropsychological deficit: comparison between patients with cardiac valve replacement and patients with coronary artery bypass grafting.

OBJECTIVES: To examine the association between intraoperative cerebral microembolic signals (MES) and postoperative neuropsychological deficit in patients with valve replacement (VR) and patients with coronary artery bypass grafting (CABG). METHODS: Neuropsychological examination (10 tests) was performed 1-2 days before and 2 months after surgery (VR (n=26) and CABG (n=14)). The intraoperative number of cerebral MES were monitored from the right middle cerebral artery using transcranial Doppler. RESULTS: A higher number of cerebral MES were detected in VR patients with neurological deficit (6/26) compared with those without deficit (20/26) (MES median number 2083 v 645, p=0.04). No such difference was found in patients with CABG (2/14 v 12/14) (MES median number 50 v 112, p=0.2). CONCLUSION: A high number of MES were detected in patients with VR with neuropsychological deficit. In patients with CABG with such a deficit, a low number of MES were detected. This difference in number may be explained by relatively more gaseous emboli in the first and more solid in the second. However, the results in the patients with CABG should be interpreted with caution due to the few patients in this subgroup.

Adult↗
PubMed1997

Cerebral microembolic signals during cardiopulmonary bypass surgery. Frequency, time of occurrence, and association with patient and surgical characteristics.

BACKGROUND AND PURPOSE: We sought to determine the number of cerebral microembolic signals (MES) and their time of occurrence during the two most frequent types of cardiopulmonary bypass (CPB) surgery: coronary artery bypass grafting (CABG) and cardiac valve replacement (VR). Furthermore, we sought to examine the association between MES, patient characteristics, and intraoperative parameters. METHODS: Forty-two patients were studied, 15 of whom had CABG and 27 VR. Cerebral MES were detected with the use of transcranial Doppler monitoring of the right middle cerebral artery. RESULTS: Cerebral MES were detected in all patients. The number was significantly higher during VR (median, 1048) than during CABG (median, 82) (P < .001). In VR patients, 85% of the MES were detected when the heart regained effective ejection. During CABG, the highest number was detected when the aorta was cross-clamped (18%) and on release of the side clamp (13%). The numbers of MES during the period when the aorta was cross-clamped and in association with surgical procedures were not significantly different in the two patient groups. The total number of MES was inversely correlated to nasopharyngeal temperature (P < .01). CONCLUSIONS: A significantly higher number of cerebral MES were detected during VR than during CABG. The highest number occurred in VR patients when effective heart ejection was regained and in CABG patients when the aorta was cross-clamped and on release of the side clamp. The total number of MES increased at lower nasopharyngeal temperatures. Transcranial Doppler monitoring may alert the surgical team when emboli enter the cerebral circulation during CPB surgery, thus allowing preventive measures to be taken.

Aged↗
PubMed1995

Incidence and frequency of cerebral embolic signals in patients with a similar bileaflet mechanical heart valve.

BACKGROUND AND PURPOSE: The aim of this study was to determine the incidence and frequency of cerebral embolic signals in a patient population with the same mechanical heart valve using transcranial Doppler examination. Furthermore, it aimed to identify patient and valve characteristics that correlated with the occurrence of these signals. METHODS: Ninety-two patients with Carbomedics valves and 15 healthy control subjects took part in the study. Thirty-six patients were examined before and immediately after valve implantation (group 1), 34 patients 1 year after surgery (group 2), and 22 patients 5 years after surgery (group 3). Cerebral embolic signals were detected using transcranial Doppler monitoring of the right middle cerebral artery. RESULTS: Asymptomatic cerebral embolic signals were detected in 87% of the total 92 patients, in 77.8% of group 1 patients, in 91.2% of group 2 patients, and in 95.5% of group 3 patients. No cerebral embolic signals were detected in group 1 patients before surgery or in control subjects. The incidence (P = .04) and frequency (P = .002) of cerebral embolic signals increased significantly with longer duration of valve implantation. A significant positive correlation was also found between frequency of cerebral embolic signals and valve size (r = .4326, P = .00001). Median frequency of embolic signals in patients with a history suggestive of cerebrovascular events (n = 14) was 60 signals per hour compared with 11 signals per hour in those with no such history (n = 42; P = .04). CONCLUSIONS: The incidence and frequency of cerebral embolic signals increased with the duration of valve implantation. The frequency of these signals also was dependent on valve size. Patients who had experienced cerebrovascular symptoms had a higher frequency of cerebral embolic signals compared with those with no such signals. These results should be interpreted with caution but suggest that this method could be of help in assessing the risk of stroke in prosthetic heart valve patients and that prospective clinical studies should now be carried out.

Adult↗