DSA examination
Early DSA is indicated for patients with confirmed or highly suspected SAH, and patients with a Hunt-Hess classification of 4-5 may be imaged after ventricular puncture, if appropriate. Systemic heparinization is not used for emergency DSA to avoid increasing the risk of bleeding during possible emergency craniotomy aneurysm clamping. Whole-brain angiography includes bilateral common carotid arteries and bilateral vertebral arteries to avoid missed dural arteriovenous fistulas in the head or occipital foramen magnum region. Vessels with clear or suspicious aneurysms on ortho-lateral angiography are recommended to be rotated and reconstructed in three dimensions, and an appropriate working angle angiography is selected for the aneurysm in order to further confirm the diagnosis of the aneurysm and clarify the anatomic relationship between the associated aneurysm and its surrounding vessels, as there may be a degree of distortion in the 3D reconstructed images. If the whole brain angiogram is negative, spinal angiogram or MRI of the head and cervicothoracic segment should be added to avoid missing other intracranial disorders or spinal vascular malformations. If the whole cerebral angiogram is negative and other diseases are excluded by the above tests, the angiogram should be reexamined after 2 weeks. He Chuan, Department of Neurosurgery, Xuanwu Hospital, Capital Medical University
Reasons for false negative whole brain angiogram: spasm of aneurysm-carrying artery, occlusion of thrombus in the aneurysm sac, small aneurysm, poor imaging equipment, no rotational imaging, three-dimensional imaging or multi-angle imaging, and incorrect reading of the film.
Timing of aneurysm treatment
The international joint study on the timing of aneurysm surgery confirmed that: the longer the time before treatment of aneurysms with aSAH, the higher the rate of rebleeding before treatment and the worse the prognosis; after the occurrence of SAH, the time before surgery is closely related to the rate of rebleeding before surgery.
Ruptured aneurysms should be treated early, especially for patients with low and moderate preoperative grading. Meanwhile, early surgery facilitates timely anti-vascular spasm treatment.
Choice of surgical or interventional treatment modality
l Aneurysm site and choice of treatment modality.
1. middle cerebral aneurysms are more difficult to embolize due to morphology, and aneurysms in this area are relatively more suitable for craniotomy than aneurysms in other areas.
2. aneurysms of the posterior circulation are more difficult to operate craniotomically, and interventional treatment is more effective.
3. for internal carotid artery aneurysms, interventional embolization is relatively easy to accomplish when comparing the two treatment modalities.
l Patient systemic condition and complications after bleeding and choice of treatment modality.
1. studies confirm that age >65 years, the complications of craniotomy are significantly increased, and interventional treatment is recommended to be considered first.
2. large hematoma with severe occupying effect, craniotomy is considered first to remove the hematoma and clip the aneurysm.
3. patients with poor neurological function score aSAH, with obvious brain swelling, severe brain tissue retraction by craniotomy, possible long intraoperative temporary block, increased risk of craniotomy, and relatively small impact on interventional treatment, interventional treatment is preferred. If the first intervention is difficult to dense embolization, palliative partial embolization should be used as appropriate to reduce the risk of rebleeding, and craniotomy should be performed to clip the aneurysm after the condition is stabilized.
4. some patients may be considered for combined treatment with endovascular embolization therapy and craniotomy for decompression
l In addition to the above.
1. if complete embolization of the aneurysm is not possible, craniotomy clamping should be considered
2. aneurysms with a neck less than 5 mm and a neck/body ratio less than 0.5 are easier to embolize completely and have a better prognosis for interventional treatment
3. the possibility of complete embolization is related to the size of the aneurysm, with a higher mortality and disability rate for giant aneurysms larger than 25 mm.
4. aneurysms smaller than 3 mm are relatively difficult to embolize and are prone to intraoperative rupture.
Interventional treatment of ruptured aneurysms
1. Preoperative tests: blood count, coagulation test, electrocardiogram. Note: Takotsubo Cardiomyopthy (apical balloon-like syndrome) is commonly seen in patients with aSAH, and the ECG shows myocardial ischemic changes. However, Takotsubo cardiomyopathy is an unexplained myocardial disease with a good prognosis, mostly occurring after stress. The clinical presentation is very similar to that of acute myocardial infarction, but there is no significant coronary stenosis on coronary angiography and apical balloon-like changes on left ventriculography or echocardiography. Appendix 6
2. general anesthesia with tracheal intubation.
3. Systemic heparinization: body weight (kg) X 2/3 = heparin (mg), 100 mg or 125,000 U heparin + water for injection to 10 ml standby. Additional half amount 1 hour after the first measurement, additional 1/4 amount after the second hour, and then maintain additional 1/4 amount every hour.
4. Uniform and dense embolization of the aneurysm capsule with no residue in the neck of the aneurysm.
5. Balloon-assisted embolization: occlusion time of the aneurysm-carrying artery should not exceed 5 min each time.
6. Stent-assisted embolization: a loading dose (clopidogrel 300mg) given 40 minutes before emergency surgery and then powdered and given orally via gastric tube; regular dose (aspirin 100mg, clopidogrel 75mg) given orally 3 days before surgery in non-emergency patients; regular dose continued for 3 months after surgery and changed to maintenance dose (aspirin 100mg) continued for 3 months; if necessary, low molecular Heparin 0.4 subcutaneous injection every 12 hours, a total of 6 times.
7. BOT trials.
7.1. neurological symptoms: 20 min without neurological symptoms.
7.2. intensification test: 20-30 mmHg reduction in mean blood pressure or maintenance of 90-100 mmHg systolic blood pressure without neurological symptoms for 20 min.
7.3. imaging to determine whether there is compensatory blood supply from the anterior communicating artery, posterior communicating artery, ophthalmic artery, etc. VanRooij proposed that 98% of patients can tolerate ischemia with a delay of 0.5 seconds or less in cortical vein development on the occluded side; Abud proposed that patients with a delay of less than 2 seconds can tolerate ischemia, patients with more than 4 seconds cannot tolerate ischemia, and 2-4 seconds may tolerate ischemia. The standard of neurosurgery in Xuanwu Hospital uses a delay of 1 second or less in cortical vein visualization on the occluded side as a criterion for tolerating ischemia.
8. Intraoperative aneurysm rupture management: after neutralizing heparin, continue to rapidly and densely fill the aneurysm. CT examination of the head should be performed as soon as possible after surgery to clarify the amount of bleeding and intracranial situation, and if necessary, external drainage by ventricular puncture or craniotomy should be performed immediately, but patients with severe bleeding in critical condition should not be treated surgically.
9. Intraoperative thrombosis management: systemic heparinization is emphasized during aneurysm embolization, especially for aneurysm embolization using double catheters, balloon-assisted, stent-assisted and other techniques. In case of significant intravascular thrombosis, rapid dense embolization of the aneurysm is followed by arterial thrombolysis with tirofiban or systemic intravenous thrombolysis.
10. Vascular spasm: If the spasm is caused by mechanical stimulation of the internal carotid artery when the Guiding catheter is in place, use a slow intra-arterial push of calcium antagonist to relieve the spasm after removing the stimulation; if the imaging suggests severe spasm of the intracranial vessels after SAH, use a slow intra-arterial push of calcium antagonist to relieve the spasm after aneurysm embolization; if the severe spasm of the intracranial vessels affects the microcatheter in place or intraoperative aneurysm visualization, use a small amount of calcium antagonist in If severe intracranial spasm interferes with microcatheterization or intraoperative aneurysm visualization, a small amount of calcium antagonist is used to relieve spasm prior to aneurysm embolization. Angioplasty and selective arterial dilatation to relieve vasospasm should be used with caution.
Postoperative MRI and MRA: MRI and TOF-MRA or CE-MRA are performed 2 weeks after aneurysm embolization to clarify cerebral vasospasm brain damage and as a reference for follow-up examination after aneurysm embolization. CE-MRA is preferred if the patient has no contrast agent adverse reaction.
12. Long-term follow-up after intervention: Studies have shown that the mean time to recurrence after aneurysm embolization is 12.3 months; therefore, long-term follow-up of patients after embolization is needed. CE-MRA was performed 2 weeks after surgery, and CE-MRA was repeated 6 and 12 months after surgery, and imaging was repeated 12 months after surgery. If there was no recurrence of CE-MRA and DSA aneurysm at 12 months, CE-MRA was repeated annually thereafter for follow-up.