Long-Term Outcomes in the Treatment of Pediatric Arteriovenous Malformations
March 22, 2021
Intracranial arteriovenous malformations (AVM) in pediatric patients represent a rare diagnosis. They are often challenging to treat in the acute phase. Simultaneously, AVM has the propensity for recurrence years after initial treatment (even though overall cases of recurrence are low), particularly those that are hemorrhagic in nature and require emergent surgical attention upon initial presentation. Hemorrhagic occurrences of AVM are more common in children than in adults, but the exact rate of incidence is not yet known. In the UPMC Children’s study summarized below more than half of the cases examined were of a hemorrhagic nature.
Younger children with AVM are more likely to have a hemorrhagic presentation, and because of this, these individuals experience poorer outcomes. These younger patients may present with early hemorrhagic AVM due to increased risk factors for hemorrhage including deep venous drainage, intranidal aneurysms, or venous outflow stenosis. Mortality rates for AVM ruptures in pediatric patients is relatively high — about 20% according to current data in the literature.
The Brain Care Institute at UPMC Children’s Hospital of Pittsburgh sees approximately five to 10 cases of AVM each year. It brings to bear upon these rare clinical presentations a multimodality treatment approach designed to achieve optimal long-term outcomes and preserve a patient’s long-term functional independence while minimizing complications.
Outcomes from 30 Years of Pediatric AVM Surgery at UPMC Children’s
Neurosurgeons from the Brain Care Institute at UPMC Children’s, all of whom are faculty members of the Department of Neurological Surgery at the University of Pittsburgh School of Medicine, published long-term findings on AVM outcomes in a retrospective study spanning 30 years of surgical cases (1988-2018). The results of study were published in September in the Journal of Neurosurgery: Pediatrics as the cover article and was the editor’s choice for this edition of the journal.
The investigation examined the long-term outcomes of AVM treatment in a cohort of 212 patients. The main objective of the analysis was to determine if outcomes varied by treatment choice — surgical approaches, endovascular techniques, radiosurgical options, including gamma knife radiosurgery. Stephanie Greene, MD, director of vascular neurosurgery at the Brain Care Institute at UPMC Children’s, was the senior author of the study designed to uncover potential variations in long-term outcomes from different treatment approaches.
“Our center has one of the longest histories in the United States treating AVM with all of the modern techniques at our disposal: embolization, gamma knife radiosurgery, and open microsurgery. Going back to cases from 1988 to roughly the present day afforded us the ability to uncover disparities in outcomes by treatment modality and to obtain a clear picture of how these long-term survivors have fared across a range of outcomes, including postoperative complications and the incidence of recurrences,” says Dr. Greene.
Much was uncovered in the study that analyzed outcomes in a cohort of 212 patients with a mean age of 11.3 years at presentation and who were followed for a mean duration of 79.7 months. A key finding was that the chosen treatment modality did not impact outcome.
“Long-term patient outcomes are best when the full clinical armamentarium is at our disposal. We can select the best possible treatment for any case that presents itself because we have the clinical capabilities and technologies to leverage against the various complexities and challenges that AVMs present,” says Dr. Greene.
Eighty-five percent of patients in the study cohort exhibited good long-term outcomes based on functional independence measures. Only six mortalities were found during the study in the postoperative period. Three of the mortalities were the result of unrelated medical conditions.
Of the remaining three (1.4% of the total study cohort), one case was the result of an AVM hemorrhage after a treatment refusal by the family; one case was attributed to AVM hemorrhage three years subsequent to a gamma knife procedure; and the third mortality occurred 15 years after a gamma knife surgery and was caused by an AVM hemorrhage.
Factors Influencing Poor Outcomes
Of the 212 individual cases analyzed in the study, 14.6% were deemed to have poor long-term outcomes. Poor long-term outcomes were more strongly associated with a higher mRS score at the time of presentation, a higher Spetzler-Martin grade, hemorrhage requiring a decompressive craniotomy, or a lack of treatment.
“The sicker a patient is when he or she presents, and the more complex their AVM is provides a good indicator for long-term prognosis and outcomes,” says Dr. Greene.
Important Findings About AVM Recurrence
An additional important finding from the analysis relates to AVM recurrence. The study found a total of five cases of recurrence (representing 3% of all cases), with a mean recurrence time of 9.5 years. Recurrence also was associated with hemorrhagic cases treated with only craniotomy.
“What this suggests, of course, is that we need to closely monitor these patients and perform follow-up imaging at regular intervals to ensure we identify recurrences as early as possible,” says Dr. Greene.
Hemorrhagic Cases
While hemorrhagic cases increase the risk for recurrence in patients, the study did not find that hemorrhagic AVM cases influenced poorer long-term outcomes in general; however, younger children — under the age of 10 — with hemorrhagic presentations did fare worse in long-term outcomes.
More About Dr. Greene
Stephanie Greene, MD, associate professor of neurological surgery, is the director of vascular neurosurgery and director of perinatal neurosurgery in the Brain Care Institute at UPMC Children’s Hospital of Pittsburgh. Dr. Greene earned her medical degree from Albany Medical College in New York, followed by residency at the Harvard Medical School/Children’s Hospital of Boston/Brigham & Women’s Hospital program, and a pediatric neurological surgery fellowship at Seattle Children’s Hospital through the University of Washington School of Medicine.
Dr. Green’s clinical and research interests are focused on vascular neurosurgery with particular emphasis on arteriovenous malformations, fetal neurosurgery, myelomeningocele, and MoyaMoya syndrome. Dr. Greene joined the Brain Care Institute at UPMC Children’s in 2009.
Reference
McDowell MM, Agarwal N, Mao G, Johnson S, Kano H, Lunsford LD, Green S. Long-Term Outcomes of Pediatric Arteriovenous Malformations: The 30-Year Pittsburgh Experience. J Neurosurg Pediatr. 2020; 26: 275-282.
