Following EVT of UIAs, the course of headache in patients with newly onset moderate-to-severe headache consistently improved over the course of 12 months of follow-up. Patients without a history of stroke and those without procedure-related complications were more likely to experience headache improvement from discharge to the 12-month follow-up. Nevertheless, approximately 13.1% of the 412 patients maintained moderate-to-severe headaches throughout the follow-up period [13, 15, 16]. Considering the impact of headaches on patients' quality of life, it is worthwhile to study the course of headache from pre-EVT through follow-ups in patients with newly onset moderate-to-severe headache.
Our findings are consistent with some previous studies. Choxi et al.[17] reported that treatment of UIAs, either through surgical clipping or EVT, was associated with a reduction in headache severity over an average follow-up period of 32.4 months. Schwedt et al.[12] found that headache frequency decreased in 68% of patients, while 9% of patients experienced new-onset or worsening headaches after aneurysm treatment in a prospective observational analysis. Gu et al.[6] reported that headaches improved in 76.9% of 72 patients over 65 years of age after EVT of UIAs, and 3.8% reported worsening. Qureshi et al.[11] reported that 68% of patients had headaches before coil embolization, and these headaches improved in 59% of patients after EVT of UIAs, with 6% reporting worsening. Park et al.[18] reported that 59 (72%) of 82 patients had headaches before EVT, and 42 (71%) of these patients reported improvements in the severity of their headaches. Factors predisposing to headache improvement after EVT were identified as aneurysm size and endovascular technique, regardless of headache characteristics [18].
However, some studies have reported new-onset headaches after EVT of UIAs. Hwang et al.[7] reported that approximately half of the 50 patients developed headaches after EVT, but these headaches were benign and resolved, on average, within 3 days of EVT. Park et al.[18] reported that new-onset headaches after EVT occurred in three (13%) of 23 patients who had no headaches before EVT. These new-onset headaches were mild (mean NRS 1.66) and resolved within 2 weeks. In our study, we were unable to evaluate patients with new-onset headaches because we only included patients with moderate-to-severe headaches before EVT. Instead, we found that 13.1% of our patients continued to experience moderate-to-severe headaches up to the 12-month follow-up.
Given that headache is the most common symptom of UIAs [1], our focus was on the intensity of headache, particularly moderate-to-severe headache that significantly impacted daily activities, in patients newly diagnosed with headache related to their diagnosis. As the course of headache following EVT has remained unclear and controversial, we aimed to identify a group of patients who experienced headache improvement over time after EVT. Neurologically asymptomatic patients were often given little attention in the past, as their clinical outcomes were generally positive. However, moderate-to-severe headaches may have greater clinical significance compared to mild headaches, as they interfere more significantly with daily activities. As such, the management of moderate-to-severe headaches should not be overlooked. Although we cannot provide an exact explanation for headache improvement in this study, we can assert that most newly onset moderate-to-severe headaches will improve after EVT of UIAs. EVT may alleviate headaches by reducing local thrombosis in the aneurysmal wall, alleviating expansion or inflammation of the aneurysm, and lessening the stimulation of perivascular sensory nerve terminals [3, 4, 2]. Above all, EVT may provide psychological relief by addressing patients' concerns, indicating that many headaches included in this study may have been stress-related tension-type headaches resulting from the diagnosis of UIAs. These results may enable healthcare providers to educate patients presenting with initially moderate-to-severe headaches before EVT of UIAs.
Several limitations should be considered when interpreting the results of this study. First, it was a retrospective study based on prospectively collected data. Patients with incomplete data and those lost to follow-up were excluded from the analyses and treated as having missing data, introducing a potential risk of selection bias. Second, we did not differentiate headache characteristics, such as type, duration, or frequency. Consequently, our results may have differed if we had assessed headache characteristics. Nonetheless, our primary focus was on the subjective measure of headache intensity (NRS score) as we were primarily concerned with headaches in general and their potential impact on daily activities. Park et al.[18] also explored the relationship between headache outcomes and coil embolization and identified factors associated with different headache outcomes in UIA patients after EVT. They concluded that headache characteristics might not be relevant as, irrespective of headache characteristics, aneurysm size, the technique employed, and EVT of UIAs resulted in headache improvement in most patients with pretreatment headaches. Third, we lacked detailed information about headache medications. While medication use is a potentially important factor affecting headache improvement, it was challenging to analyze when or how medications were used. We attempted to evaluate the correlation between a history of headaches treated with medications and headache improvement in patients with newly onset moderate-to-severe headaches before EVT. Finally, we did not assess psychiatric factors. Patients with psychiatric symptoms, such as anxiety, before EVT of UIAs may have a higher risk of persistent headaches. Anxiety may represent a risk factor for chronic headaches associated with UIAs and carries significant clinical implications. Future research should examine the role of preoperative psychiatric symptoms in the course of headaches after EVT of UIAs.