• Journal of Korean Neurosurgical Society
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• v.55 no.2
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• pp.69-72
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• 2014

Objective : There was no abundance of data on the use of anticoagulant in patients with previous high risk of thromboembolic conditions under a newly developed intracranial hemorrhage in Korean society. The purpose of this study was to evaluate the safety of discontinuance and suggest the proper time period for discontinuance of anticoagulant among these patients. Methods : We reviewed the medical records of 19 patients who took anticoagulant because of thromboembolic problems and were admitted to our department with newly developed anticoagulation associated intracranial hemorrhage (AAICH), and stopped taking medicine due to concern of rebleeding from January 2008 to December 2012. Analysis of the incidence of thromboembolic complications and proper withdrawal time of anticoagulant was performed using the Kaplan-Meier method. Results : Our patients showed high risk for thromboembolic complication. The $CHA_2DS_2$-VASc score ranged from two to five. Thromboembolic complication occurred in eight (42.1%) out of 19 patients without restarting anticoagulant since the initial hemorrhage. Among them, three patients (37.5%) died from direct thromboembolic complications. Mean time to outbreak of thromboembolic complication was $21.38{\pm}14.89$ days (range, 8-56 days). The probability of thromboembolic complications at 7, 14, and 30 days since cessation of anticoagulation was 0.00, 10.53, and 38.49%, respectively. Conclusion : Short term discontinuance of anticoagulant within seven days in patients with AAICH who are at high embolic risk ($CHA_2DS_2$-VASc score >2) appears to be relatively safe in Korean people. However, prolonged cessation (more than seven days) may result in increased incidence of catastrophic thromboembolic complications.

• Journal of Korean Neurosurgical Society
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• v.46 no.3
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• pp.226-231
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• 2009

Objective : We describe our clinical experiences and outcomes in patients who had thromboembolic complications occurring during endovascular treatment of intracerebral aneurysms with a review of the literature. The types of thromboembolic complications were divided and the treatment modalities for each type were described. Methods : Between August 2004 and March 2009 we performed endovascular embolization with Guglielmi detachable coils for 173 patients with 189 cerebral aneurysms, including ruptured and unruptured aneurysms at our hospital. Sixty-eight patients were males and 105 patients were females. The age of patients ranged from 22-82 years (average, 58.8 years). We retrospectively evaluated this group with regard to complication rates and outcomes. The types of thromboembolic complications were classified into the following three categories: mechanical obstruction, distal embolic stroke, and stent-induced complications, which corresponded to types I, II, and III, respectively. A comparison of the clinical results was made for each type of complication. Results : Only eight patients had a thromboembolic complication during or after a procedure (4.6%). Of the eight patients, two had a mechanical obstruction as the causative factor; the other three patients had distal embolic stroke as the causative factor. The remaining three patients had stent-induced complications. In cases of mechanical obstruction, recanalization occurred due to the use of intra-arterial thrombolytic agents in one of two patients. Nevertheless, a poor prognosis was seen. In the cases of stent-induced complications, in one of three patients in whom a thrombus developed following stent insertion, a middle cerebral artery territory infarct developed with a poor prognosis despite the use of wiring and an intra-arterial thrombolytic agent. In the cases of distal embolic stroke, all three patients achieved good results following the use of antiplatelet agents. Conclusion : Treatment for thromboemboic complications due to mechanical obstruction and stent-induced complications include antiplatelet and intra-arterial thrombolytic agents; however, this cannot guarantee a sufficient extent of effectiveness. Therefore, active treatments, such as balloon angioplasty, stent insertion, and clot extraction, are helpful.

• Journal of Chest Surgery
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• v.41 no.4
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• pp.430-438
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• 2008

Background: All the patients with mechanical valves require warfarin therapy in order to prevent them from developing thromboembolic complications. According to the ACC/AHA practice guidelines, after AVR with bileaflet mechanical prostheses in patients with no risk factors, warfarin is indicated to achieve an INR of 2.0 to 3.0. After MVR with any mechanical valve, warfarin is indicated to achieve an INR of 2.5 to 3.5. But in our clinical experience, bleeding complications (epistaxis, hematuria, uterine bleeding, intracerebral hemorrhage etc.) frequently developed in patients who maintained their INR within this value. So, we retrospectively reviewed the patients with bileaflet mechanical heart valve prosthesis and we determined the optimal anticoagulation value. Material and Method: From January 1984 to February 2007, 311 patients have been followed up at a national medical center. We classified the AVR patients (n=60) into three groups as follows: an INR from 1.5 to 2.0 in Group I, an INR from 2.0 to 2.5 in Group II and an INR from 2.5 to 3.0 in Group III. We classified the MVR (n=171) and DVR (n=80) patients into four groups as follows: an INR from 1.5 to 2.0 in Group I, an INR from 2.0 to 2.5 in Group II, an INR from 2.5 to 3.0 in Group III and an INR from 3.0 to 3.5 in Group III. We compared the groups for their thromboembolic and bleeding complications by means of the Kaplan Meier method. Result: In the AVR patients, 2 thromboembolic complications and 4 bleeding complications occurred and the log rank test failed to identify any statistical significance between the groups for thethromboembolic complication rate, but groups I and II had lower bleeding complication rates than did group III. Thirteen thromboembolic complication and 15 bleeding complication occurred in the MVR and DVR patients, and the log rank test also failed to identify statistical significance between the groups for the thromboembolic complication rate, but groups I and II had lower bleeding complication rates that did groups III and IV. Conclusion: The thromboembolic complication rate was not statistically different between groups I and II and groups III and IV, but the bleeding complication rates of groups I and II were lower than those of groups III and IV. So this outcome encouraged us to continue using our low intensive anticoagulation regime, that is, an INR of 1.5 to 2.5.

• Journal of Korean Neurosurgical Society
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• v.61 no.2
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• pp.201-211
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• 2018

Objective : The purpose of this study was to analyze the variability of clopidogrel responses according to duration of a clopidogrel drug regimen after stent-assisted coil embolization (SAC), and to determine the correlation between the variability of clopidogrel responses and thromboembolic or hemorrhagic complications. Methods : A total of 47 patients who underwent SAC procedures to treat unruptured intracranial aneurysms were enrolled in the study. Preoperatively, patients received more than seven days of aspirin (100 mg) and clopidogrel (75 mg), daily. P2Y12 reaction unit (PRU) was checked with the VerifyNow test one day before the procedure (pre-PRU) and one month after the procedure (post-PRU). PRU variability was calculated as the difference between the initial response and the follow-up response. Patients were sorted into two groups based on their response to treatment : responsive and hypo-responsive. Results : PRU variability was significantly greater in the hypo-responsive group when compared to the responsive group (p=0.019). Pre-PRU and serum platelets counts were significantly correlated with PRU variation (p=0.005 and p=0.004, respectively). Although thromboembolic complication had no significant correlated factors, hemorrhagic complication was correlated with pre-PRU (p=0.033). Conclusion : In conclusion, variability of clopidogrel responses during clopidogrel medication was correlated to serum platelet counts and the initial clopidogrel response. Thromboembolic and hemorrhagic complications did not show correlation with the variability of clopidogrel response, or the clopidogrel response after one month of medication; however, hemorrhagic complication was associated with initial clopidogrel response. Therefore, it is recommended to test patients for an initial clopidogrel response only, as further tests would be insignificant.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.48-54
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• 1987

This report provides follow-up data on 557 patients [73 aortic, 357 mitral, and 127 multiple valve replacements] undergone lonescu-Shiley pericardial Xenograft valve replacement at Seoul National University Hospital between January, 1979 and December, 1985. There were 35 early death [6.3%] and 522 operative survivors were observed, and the cumulative follow-up is 1,140 patient-years [mean: 2.18 years per patient] The thromboembolic complications occurred in 34 cases [3.0% per patient-year] and the rate was 2.1% per patient-year for mitral and 0.3% per patient-year for aortic valve replacement in the presence of anticoagulation therapy. Among the 34 embolic episodes, 9 patients were dead [0.8% per patient-year] and the cause of death were 5 cerebral thromboembolism, 2 pulmonary embolism, and 2 intracerebral hemorrhage due to inappropriate anticoagulation after thromboembolic episode. Actuarial probability [+ SEM] of remaining free of thromboembolism for AVR is 88.1 x 11.1% at 5 years, for MVR 79.1 a 13.4% at 7 years and for multiple valve replacement 77.2 e 5.21% at 7 years. The incidence rate of thromboembolic complications after AVR is not less than that of MVR [0.3 Among the potential thromboembolic risk factors, atrial fibrillation is possible risk factor to increase the thromboembolic complication [0.05 < P < 0.1], but the importance of other factors, such as atrial clot, large left atrial size, mitral position, NYHA functional class, and age is less definite. A careful follow-up and the proper control of anticoagulation without omission, poor control, and arbitrary withdrawal is important for the successful management of the thromboembolic complications and the anticoagulation-related morbidity and mortality.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.40-48
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• 2022

Objective : Placement of a single transverse stent via the nondominant A1 across the anterior communicating artery (AComA) into the contralateral A2 can provide sufficient neck coverage for wide-necked bifurcation AComA aneurysms. The authors described the feasibility, safety and long-term outcomes of this technique. Methods : Between January 2015 and February 2018, placement of a single transverse stent via the nondominant A1 was attempted in 17 wide-necked bifurcation AComA aneurysms. The authors reviewed the medical records and radiological studies. Results : The technical success rate was 94.1% (16/17). Periprocedural thromboembolic complications occurred in one patient (6.3%) without permanent neurological deficits. The mean clinical follow-up duration was 39.9±9.8 months. No deaths or delayed thromboembolic complications occurred. The mean angiographic follow-up duration was 38.9±9.8 months. The immediate and final follow-up complete occlusion rates were 87.4 and 93.7%, respectively. There was no recanalization during the follow-up period. Conclusion : Placement of a single transverse stent via the nondominant A1 across the AComA into the contralateral A2 is a feasible and relatively safe endovascular technique for the treatment of wide-necked bifurcation AComA aneurysms, with good long-term occlusion rates and a reasonable complication rate, if only the nondominant A1 is applicable.

• Journal of Korean Neurosurgical Society
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• v.48 no.4
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• pp.319-324
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• 2010

Objective : The aim of this study was to analyze the correlation between thromboembolic complications and anti platelet drugs before and after neurointervention. Methods : Blood samples and radiographic data of patients who received a neurointervention (coil embolization, stent placement or both) were collected prospectively. Rapid platelet function assay-aspirin (RPFA-ASA) was used to calculate aspirin resistance in aspirin reaction units (ARU). For clopidogrel resistance, a P2Y12 assay was used to analyze the percentage of platelet inhibition. ARU > 550 and platelet inhibition < 40% were defined as aspirin and clopidogrel resistance, respectively. Results : Both aspirin and clopidogrel oral pills were administered in fifty-three patients before and after neurointerventional procedures. The mean resistance values of all patients were 484 ARU and < 39%. Ten (17.0%) of 53 patients showed resistance to aspirin with an average of 597 ARU, and 33 (62.3%) of 53 patients showed resistance to clopidogrel with an average of < 26%. Ten patients demonstrated resistance to both drugs, 5 of which suffered a thromboembolic complication after neurointervention (mean values : 640 ARU and platelet inhibition < 23%). Diabetic patients and patients with hypercholesterolemia displayed mean aspirin resistances of 513.7 and 501.8 ARU, and mean clopidogrel resistances of < 33.8% and < 40.7%, respectively. Conclusion : Identifying individuals with poor platelet inhibition using standard regimens is of great clinical importance and may help prevent cerebral ischemic events in the future. Neurointerventional research should focus on ideal doses, timing, choices, safety, and reliable measurements of anti platelet drug therapy, as well as confirming the clinical relevance of aggregometry in cerebrovascular patients.

• Journal of Korean Neurosurgical Society
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• v.60 no.4
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• pp.471-474
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• 2017

Objective : The thromboembolic events during neuroendovascular therapy (NET) are the major complications of concern that can be occasionally fatal. The thrombotic occlusion of the guide catheter for NET is thought to be the risk of the thromboembolic events. We have developed an idea for inventing the monitoring system of the continuous irrigation through the guide catheter. We herein present a unique invention of the guide catheter irrigation monitoring device. Methods : We have developed ideas for preventing the thrombotic occlusion of the guide catheter. In order to design a convenient device working in the practical use, we have consulted and shared the ideas with the electrical engineers about putting the invention. Results : The guide catheter irrigation monitoring device (GCIMD) consisted of three parts of optical sensor, main body and electric adapter. In brief, the basic principles of working of the GCIMD are as follows. The optical sensor is attached to the dripping chamber of the line to irrigation solution. The main body had the small light and speaker to make an alarm sounds. The sensor monitors the dripping of flush solution. If the dripping stops more than three seconds, a warning alarm has been activated. So, the operating physicians can concentrate and check the guide catheter irrigation. After the use of the GCIMD, there was no major thromboembolic complication in conjunction with the thrombotic occlusion of the guide catheter in our institute. Conclusion : We have developed a brilliant invention of the GCIMD for NET.

• Journal of Korean Neurosurgical Society
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• v.52 no.3
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• pp.187-192
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• 2012

Objective : Stent-assisted coiling on intracranial aneurysm has been considered as an effective technique and has made the complex aneurysms amenable to coiling. To achieve reconstruction of intracranial vessels with preservation of parent artery the use of stents has the greatest potential for assisted coiling. We report the results of our experiences in ruptured wide-necked intracranial aneurysms using Y-stent coiling. Methods : From October 2003 to October 2011, 12 patients (3 men, 9 women; mean age, 62.6) harboring 12 complex ruptured aneurysms (3 middle cerebral artery, 9 basilar tip) were treated by Y-stent coiling by using self-expandable intracranial stents. Procedural complications, clinical outcome, and initial and midterm angiographic results were evaluated. The definition of broad-necked aneurysm is neck diameter over than 4 mm or an aneurysm with a neck diameter smaller than 4 mm in which the dome/neck ratio was less than 2. Results : In all patients, the aneurysm was successfully occluded with no apparent procedure-related complication. There was no evidence of thromboembolic complication, arterial dissection and spasm during procedure. Follow-up studies showed stable and complete occlusion of the aneurysm in all patients with no neurologic deficits. Conclusion : The present study did show that the Y-stent coiling seemed to facilitate endovascular treatment of ruptured wide-necked intracranial aneurysms. More clinical data with longer follow-up are needed to establish the role of Y-stent coiling in ruptured aneurysms.

• Journal of Korean Neurosurgical Society
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• v.46 no.6
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• pp.545-551
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• 2009

Objective : Complex aneurysms such as fusiform and very small aneurysms (< 3 mm) are challenging in neurovascular and endovascular surgery. Author reports follow-up results of 9 cases treated by sole stent technique with pertinent literature review. Methods : A retrospective study was made of 9 patients who were treated by sole stenting technique for cerebral aneurysm between January 2003 and January 2009. Two of them had fusiform aneurysm, 5 had very small aneurysm, and 2 had small saccular aneurysm. Five patients had ruptured aneurysms and four had unruptured aneurysms. Seven aneurysms were located in the internal carotid artery (ICA), 1 in the middle cerebral artery (MCA) and 1 in the basilar artery. Follow-up cerebral angiography was performed at post-procedure 3 months, 6 months, and 12 months. Mean follow-up period is 30 months (ranged from 3 days to 30 months). Results : Aneurysm size was decreased in 6 of 9 cases on follow-up images and was not changed in 3 cases. Although total occlusion was not seen, patients had stable neurological condition and angiographic result. The procedural complication occurred in 2 cases. One was coil migration and the other was suboptimal deployment of stent, and both were asymptomatic. Re-bleeding and thromboembolic complication had not been occurred. Conclusion : Sole stenting technique is relatively effective and safe as an alternative treatment for fusiform and very small aneurysms.