Neurological outcome and efficacy of AVM treatment

Abstract

The goal of any treatment for AVM is to aim for complete occlusion. This must be confirmed by catheter angiography. Incompletely occluded AVM still poses a risk of haemorrhage. In this chapter we have performed a literature search in PubMed database using keywords “brain avm” up to end of 2016. All series, where the method of treatment was clearly defined, the series of patients was larger than 30 and the major morbidity and mortality was clearly stated were included. In the literature review, we identified 32 surgical studies, analysing altogether 4296 patients with a mean age of 39 years. Mean efficacy within published microsurgical series was 96.9% (95% CI 95.7-97.9%) and the complication rate ranged from 1.2% to 21% with mean of 7.1% (95% CI 5.6-8.8%). Mean efficacy within 33 endovascular series comprising of 4787 patients with mean age of 35 years was 21.9% (95% CI 16.0-28.5%) and the mean complication rate was 7.4% (95% CI 6.3-8.5%). Literature review on LGK treatment was based on 45 studies comprising of 9489 patients with mean age of 31 years. The mean efficacy within studied series was 64.2% (95% CI 59.4-68.9%) and the mean morbidity and mortality was 6.7% (95% CI 5.5-8.0%). Our cohort is made up of 294 patients (171 men, 123 women) treated at the Department of Neurosurgery, Charles University and Central Military Hospital, Prague. The patients received treatment between 1st January 1995 and 31st December 2016. The database was developed prospectively, the patients’ data were assessed retrospectively. The patient’s age span was between 9 and 87 years of life, mean age was 41.8 years. The surgical group consisted of 131 patients, 32 of whom had undergone preoperative embolization of their AVM. Endovascular treatment alone was used for 59 patients, 55 patients were referred to the centre of radiosurgery, 41 directly and 14 after previous partial treatment (13 via endovascular means, 1 surgically), the remaining 49 were advised to undergo a policy of “watch and wait”. Fourteen out of the 131 surgical patients were admitted in a serious condition marked by severe neurological deficit or a GCS of < 9. Three patients in this group were admitted after bleeding from previously irradiated AVM. Preoperative embolization was used in 32 cases. A serious complication after surgery occurred in four patients; two of which (S-M grade III and IV) died. Surgical morbidity and mortality was thus 3.8%. Four AVMs (3.8%) had not been removed completely, which gives efficacy of surgery 96.2%. In the endovascular group, 59 patients had total of 102 endovascular procedures. One patient was admitted after bleeding from previously irradiated AVM. As an embolization agent was used Onyx in 34 cases and NBCA in 25. In addition, coils were used in nine cases, mainly for treatment of flow-related aneurysms. There were four cases of unmanageable haemorrhage during embolization; in another case embolization caused severe neurological deficit due to inadverent occlusion of major cerebral artery. All these patients died. Consequently, the endovascular group morbidity and mortality amounts to 8.5% (patient-related) and 4.9% (procedure-related). Complete occlusion was achieved in 22 AVMs, which is success rate of 37.3% per patient and 21.6% per procedure. Fifty-five patients were shared with the LGK unit; 41 patients were referred there for treatment primarily and 13 patients were referred to the LGK unit after previous partial embolization of AVM and one after surgery. The observation group consists of 49 patients. Eight of them underwent active treatment for some other neurosurgical pathology. In one case AVM thrombosed spontaneously after minor bleeding. We encountered two bleedings with subsequent deaths in group of patients under observation. On the acceptance of 1.1% annual bleeding rate as was found in ARUBA study and acceptance of 30% probability of poor recovery after AVM-related bleeding, comparisons of a 40-year outlook of bleeding and poor outcome in patients treated with the particular techniques is given. These comparisons is favouring microsurgery as a method of choice when AVM could be safely resected. Further analysis of endovascular treatment shows that only after 10-15 years post-embolization is the patient’s prognosis more favourable than the natural course of the disease with regard to potential risk of bleeding. Analysis of prognosis of poor outcome after embolization shows that significant effect of curative embolization disappear.