Korean Journal of Cerebrovascular Surgery 2010;12(3):182-189.
Published online September 1, 2010.
Comparison of the Complications Arising After Superficial Temporal Artery-Middle Cerebral Artery Anastomosis in Adult Moyamoya Disease and Atherosclerotic Disease.
Kim, Yong Chan , Kim, Seung Hyun , Bang, Jae Seung , Hwang, Gyojun , Kwon, O Ki , Oh, Chang Wan
1Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea.
2Department of Neurosurgery, Kang-Nam General Hospital, Seoul, Korea.
3Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea. wanoh@snu.ac.kr
Abstract
OBJECTIVE
To assess the results of superficial temporal artery-middle cerebral artery anastomosis (SMA) in atherosclerotic disease (ASD) and in adult moyamoya disease (MMD) by comparing the complications that arise. METHODS: We retrospectively reviewed patients with ASD or adult MMD treated by means of SMA, between December 2004 and December 2006, at our neurovascular center. During this period, we performed 115 SMAs on 108 patients: 61 on ASD patients (61 SMAs; the ASD group) and 47 on adult MMD patients (54 SMAs; the MMD group). RESULTS: We found a higher incidence of permanent neurological deficits (PNDs) and a lower incidence of transient neurological deficits (TNDs) in the MMD group than in the ASD group (p-value=0.047). Patients with a preoperative stroke (cerebral infarction/hemorrhage) history were more likely to develop postoperative PND than were the patients with a preoperative history of transient ischemic attack (TIA), in both the ASD (p-values=0.012 and 0.033, respectively) and MMD groups (p-values=0.000 and 0.015, respectively), regardless of overall patients (n=108) and single SMA group (n=62). Delayed seizure (seizure occurring > 1 month after SMA) occurred only in 8 MMD patients (8/47, 17.0%; p-value=0.003) out of all 108 patients and in 2 patients (2/10, 20%, p-value=0.014) out of the single SMA group. CONCLUSION: Regardless of whether the diagnosis is ASD or MMD, patients with TIA preoperatively seem more prone to develop postoperative TND, and patients with a stroke history seem more prone to develop PND in both ASD and MMD groups. However, MMD patients appear more likely to experience a delayed seizure attack after SMA than ASD patients are.
Key Words: STA-MCA anastomosis, Atherosclerotic disease, Moyamoya disease, Complications
 

Introduction


The literature describes moyamoya disease (MMD) as achronic, hemodynamic cerebral ischemia usually presenting as recurrent episodes of transient ischemic attacks (TIAs), infarctions, and hemorrhages.8)9)13)26-28) Reportedly, direct bypass surgery is effective at preventing further acute cerebral infarction in cases of hemodynamic cerebral ischemia caused by atherosclerotic stenosis/occlusion or MMD.1)2)4)6)8)11)12)20)30) Reichman et al.15)17-19) reported cerebral revascularization complications following superficial temporal artery-middle cerebral artery anastomosis (SMA) in cerebrovascular occlusive disease, and Hiroyuki et al.7) reported that, because of the special vasoreactivities peculiar to MMD, SMA in MMD has a higher risk of perioperative ischemic events than it has in other cerebrovascular occlusive diseases. However, little comparative information is available regarding postoperative complications after SMA in MMD or atherosclerotic disease (ASD). In the present study, we focused on the SMA postoperative complications in ASD and MMD patients and analyzed our findings statistically.


Materials and Methods


1. Patients

We retrospectively reviewed patients with ASD or adult MMD treated by SMA from December 2000 to December 2006 at our neurovascular center. During that period, we conducted 115 SMA operations in 108 patients: 61 ASD patients and 47 adult MMD patients. Of the 47 adult MMD patients, 40 underwent unilateral SMA, and 7 underwent bilateral SMA. We reviewed their clinical and radiological data for the following: demographics, medical comorbidities, preoperative symptoms due to a TIA or stroke (cerebral infarction/hemorrhage), postoperative neurological deficits (transient or at postoperative 1 month), postoperative seizure attack (< and > 1 month post-SMA), SMA surgical modalities, and post-SMA stroke recurrence.


2. Operative procedures

We discontinued patients?oral antiplatelet agents (aspirin, clopidogrel) for 1 week pre-SMA and restarted them on the 1st day post-SMA, at 100 mg aspirin daily. All bypass operations were performed on symptomatic patients who had preoperatively experienced TIA or stroke (infarction or hemorrhage) with reduced cerebral perfusion and cerebrovascular reserve capacity. We performed five different types of direct bypass operations on the 61 ASD and 47 adult MMD patients. These were single SMA, double-barrel SMA, SMA with encephalomyosynangiosis (EMS), SMA with encephaloduroarteriosynangiosis (EDAS), and SMA with encephaloduroarteriomyosynangiosis (EDAMS). All SMA procedures were performed by the same neurosurgeon. During the single SMA procedure, we performed direct end-to-side anastomosis, using a branch of the superficial temporal artery (STA) as a donor artery and an angular branch of the middle cerebral artery (MCA) as the recipient artery. During double-barreled SMA, we performed two SMAs, using the STA? frontal and parietal branches as donor arteries and the MCA? angular/frontal branches as recipient arteries. During SMA with EMS, we performed the EMS using the temporalis along with the single SMA procedure, and during SMA with EDAS, we performed the EDAS using the STA? parietal branch and carried out the single SMA using the STA? frontal branch. Finally, during SMA with EDAMS, we performed the EDAMS using the STA? parietal branch and the temporalis, in addition to performing the single SMA using the STA? frontal branch. Recently, we began routinely performing single SMA or SMA with EDAS rather than SMA with EMS or EDAMS, because the latter two produce more complications that are hemorrhagic and the operations take longer.


3.  Statistical analysis

Statistical analysis was performed using Pearson? chisquare test. We accepted p values of <0.05 as indicating statistical significance, and we accomplished the analyses via SPSS Version 13.0 for Windows.


Results


1.  Demographics and surgical modalities

We performed 115 SMA surgical procedures on 108 patients (61 ASD patients and 47 adult MMD patients), and 7 MMD patients underwent bilateral SMA. The mean age of all 108 study participants was 48.6 years (range, 18-76 years), and the male to female ratio was 58:50. The mean follow-up period was 31.8±19.5 months. We also investigated the demographics of the 62 patients in the single SMA surgical group (Tables 1). We performed 61 SMA procedures on the 61 ASD patients and 54 SMA operations on the 47 adult MMD patients (Table 2). Surgical trends differed between the ASD and MMD groups. Single SMA accounted for most procedures in the ASD group (52/61, 85.2%), but SMA with EDAS (16/54, 29.6%) and SMA with EMS (15/54, 27.8%) contributed most to the MMD group. The 10 MMD patients underwent 10 single SMA operations. Because different surgical modalities can bias analytical results, we analyzed the clinical results using two different sets: all 115 cases (61 ASD cases and 54 MMD cases) and the 62 single SMA cases (52 ASD cases and 10 MMD cases; Tables 1, 3, 4, 5, and 6).     


2. Clinical complications

Out of the 115 SMA procedures, intraoperative occlusion of the bypass pedicle developed in 3 patients (2 in the ASD group and 1 in the MMD group). We performed intraoperative thrombectomy in 1 of these ASD cases and achieved good recanalization, but the other 2 patients fortunately had no definite postoperative neurological symptoms. During follow-up, we observed SMA bypass pedicle patency in 60 ASD cases (60/61, 98.4%) and 53 MMD cases (53/54, 98.1%).

We classified postoperative neurological deterioration into three categories: transient neurological deficits (TND) in which patients fully recovered within 1month of follow-up period, postoperative 1 month neurological deficits (P1ND), in which they still showed deficit at 1 month, and deficit at final follow-up (major deficit with KPS ≤ 70; minor deficit with KPS ≥80). Table 3 summarizes the TND and P1ND results for the ASD and MMD patients. Out of the 61 ASD cases (Table 3-1), TND developed in 25 (41.0%), and P1ND developed in 4 (6.6%). Among the 54 MMD cases, TND developed in 12 (22.2%), and P1ND developed in 9 (16.7%), demonstrating a higher P1ND incidence and a lower TND incidence in the MMD group (p-value=0.047). However, in the 62 single SMA surgical group, we did not observe the same relationships (p-value=0.520; Table 3-2).

We investigated the correlation between preoperative symptoms and signs and postoperative neurological deterioration in the ASD and MMD groups. In the ASD group, of 24 patients with preoperative TIA symptoms, 6 (25%) had TND, but none had P1ND (Table 4-1). On the other hand, of 37 patients with preoperative stroke, 4 (10.8%) had P1ND, and 19 had TND. In the MMD group, 7 patients underwent bilateral bypass operations due to hemispheric TIA or stroke; thus, we performed 54 SMA operations on 47 MMD patients. Of 36 MMD cases with preoperative TIA symptoms, 2 (5.6%) had P1ND, and 4 (11.1%) had TND (Table 4-1). On the other hand, 7 cases (38.9%) of P1ND and 8 cases (44.4%) of TND occurred among the 18 cases with preoperative stroke. These results demonstrated that postoperative neurological deterioration correlated with preoperative symptoms and signs (TIA versus stroke) in ASD (p-value=0.012) and MMD patients (p-value=0.000).

Our investigation of the correlations between preoperative symptoms and signs and postoperative neurological deterioration in the single SMA surgical group (Table 4-2) showed comparable results (p-value=0.033 in the ASD group and 0.015 in the MMD group). Therefore, these results suggest that the disease entity, rather than the surgical modality, is responsible for the correlations between preoperative symptoms and signs and postoperative neurological deterioration.

Regarding postoperative seizure, acute seizure (a seizure attack less than 1 month post-SMA) occurred in 4 ASD (4/61, 6.6%) and 4 MMD patients (4/47, 8.5%). However, delayed seizure (a seizure attack at > 1 month post-SMA) occurred in 8 MMD patients, only (8/47, 17.0%) (Table 5-1). Of the 4 ASD patients suffering an acute seizure attack, 3 (75%) had a postoperative imaging abnormality (cerebral infarction in 2, subdural fluid collection in 1), but among the 4 MMD patients with an acute seizure attack, only 1 had a postoperative imaging abnormality (subdural fluid collection). Delayed seizure only occurred in MMD patients (p-value=0.003). We found postoperative imaging abnormalities (infarctions) in 3 of 8 MMD patients who experienced a delayed seizure attack. Mean time from SMA to delayed seizure attack in these 8 patients was 16.9±20.0 months. The surgical modalities used for these 8 patients with a delayed seizure were as follows: 1 case of single SMA, 2 cases of SMA with EDAS, 4 cases of SMA with EMS, and 1 case of SMA with EDAMS. When we investigated

postoperative seizures among ASD and MMD patients in the single SMA surgical group (Table 5-2), we obtained the same statistical results (p-value=0.014). In other words, postoperative delayed seizure seemed to occur more frequently in MMD than in ASD patients regardless of their bypass modality.

During follow-up, 1 patient (1/61, 1.64%) in the ASD group and 4 patients (8.5%) in the MMD group experienced post-SMA stroke recurrence. However, in the 4 MMD patients, only 1 (2.1%) experienced a ?rue?recurrence related to the bypass surgery (i.e., an MCA territory infarction). The other 3 patients experienced an intraventricular hemorrhage (n=2), or a brainstem (medulla) infarction. Thus, the ischemic stroke recurrence rate in ASD and MMD patients post-SMA did not differ (p-value=0.852).

Only one mortality occurred with a direct relation to the surgery. This mortality occurred in the MMD group, and its cause was a postoperative epidural hematoma and a massive intracerebral hemorrhage (ICH), which we attributed to a hyperperfusion injury from the bypass surgery. In addition, 3 (4.9%) ASD group patients and 1 (2.1%) MMD group patient died during follow-up, due to angina, pneumonia, and other medical diseases.

Wound infections developed in 2 ASD cases (2/61, 3.3%) and 3 MMD cases (3/54, 5.6%), but this difference was not statistically significant (p-value=0.550).

But, considering final follow-up neurological status of the 108 patients, in spite of postoperative immediate deteriorations, their neurological status are not so bad. Major morbidity (Karnofsky performance scale (KPS)≤70) was 6.4% (3 patients) in 47 MMD patients and 0% in 61 ASD patients. Minor morbidity ( 80≤KPS≤90) was also 6.4% (3 patients) in 47 MMD patients and 1.6% (1 patient) in 61 ASD patients.


3. Radiological complications

Table 6-1 summarizes the ASD and MMD groups?radiological complications according to radiological examinations within postoperative 2 weeks. ICH developed in 4 ASD cases (6.6%) versus 3 MMD cases (5.6%), and cerebral infarction developed in 6 ASD cases (9.8%) versus 6 MMD cases (11.1%). Of the 3 ICH patients in the MMD group, 2 underwent decompressive craniectomy surgery, and 1 subsequently succumbed to a massive cerebral swelling. Hemorrhagic complications developed more often in the MMD group (11/54, 20.4 %) than in the ASD group (5/61, 8.2%), but in the single SMA group, we observed no such significant difference between ASD and MMD patients. However, this comparison is of

limited validity, because it involved only 10 MMD patients (Table 6-2).


Discussion


Reportedly, cerebral circulation? hemodynamics in MMD are characterized by low cerebral blood flow (CBF) and extremely high vascular resistance in the collaterals at the base of the brain, and therefore SMA has been viewed as a logical treatment modality for providing a readily accessible blood supply.29)

We investigated the differences between ASD and MMD patients that underwent SMA in terms of postoperative neurological deterioration, effects of preoperative TIA/stroke, postoperative seizures (acute and delayed), and radiological complications. To date, no other study has compared MMD and ASD patients in terms of complications arising after SMA.

Reportedly, transient neurological deterioration post-SMA occurs in approximately 4% to 20% of MMD patients.3)5)10)14)16)21-25) In the present study, TND rates after SMA were 22.2% (12/54) for all study participants (n=108) and 40.0% (4/10) for the single SMA group (n=62).

However, the etiologies of these transient postoperative neurological deficits remain unknown. Robertson and Watridge22) suggested they occur due to temporary occlusion of the cortical vessels, while Reichman16) thought they might be related to the sacrifice of penetrating branches from recipient cortical vessels. However, these reports cannot explain the difference we observed between TND and P1ND incidences in the ASD and MMD groups.

In the present study, we found a higher incidence of P1ND and a lower incidence of TND in the MMD group than in ASD group (p=0.047; Table 3-1), but we did not find these in the single SMA group (62 patients; Table 3-2). This apparent disparity suggests that surgical modality, rather than disease entity, affects TND and P1ND incidences.

However, we consider that the different incidences of TND and P1ND are likely due to several factors, e.g., hemodynamic collateral circulation, surgical modality, or radiological complications. Several factors also influence hemodynamic collateral circulation, such as the development of collateral vessels in the periprocedural area, the presence of major cerebral vessels, vascular resistance, cardiac function, and the disease entity. Of these factors, an existing cerebral infarction supposedly influences the development of collateral vessels in the periprocedural area. We suppose that, if a preoperative cerebral infarction is present in the planned SMA area, it will retard the development of local collateral vessels, and the probability of a postoperative TND/P1ND will likely increase, The data in Table 4 support this idea. In the present study, we found postoperative neurological deterioration correlated with preoperative symptoms and signs (TIA versus stroke) in the ASD and MMD groups. Furthermore, we found patients with a preoperative stroke history were more prone to postoperative PND than were patients with a preoperative TIA history associated with ASD (p-values=0.012 and 0.033, respectively) or MMD patients (p-values=0.000 and 0.015, respectively), among either all study participants (n=108) or the single SMA group (n=62).

In addition, MMD reportedly can influence hemodynamic collateral circulation. Ogawa et al.13) reported CBF (cerebral blood flow) is significantly lower in MMD patients than in normal age-matched controls and CBF distribution shows a dominant posterior distribution in MMD, in contrast with the dominant anterior distribution in normal controls. Taki et al.27) investigated cerebral circulation and metabolism in patients with adult MMD, using positron emission tomography, and concluded a mild reduction in perfusion pressure and a prolonged circulation time characterizes the cerebral circulation in adult MMD.

In addition to hemodynamic collateral circulation, researchers also believe surgical modalities and radiological complications influence the incidences of TND and P1ND. Table 2 shows the different SMA surgical patterns in our ASD and MMD patients. In MMD patients, SMA with

EDAS (16/54, 29.6%) and SMA with EMS (15/54, 27.8%) accounted for most SMA surgeries, whereas this was not the case in ASD patients. Because SMA with EDAS or EDAMS needs a larger surgical field and more surgical time than single SMA does, physicians might want to regard hemorrhagic complications and postoperative radiological complications as more important issues in MMD patients than they are in ASD patients.

We found a statistical difference between the ASD and MMD groups with regard to postoperative seizure incidence (n=108, p-values=0.012, 0.000; Table 5-1) and between ASD and MMD patients in the single SMA group (n=62, p-values=0.033, 0.015; Table 5-2). In particular, postoperative seizures within 1 month of SMA occurred only in MMD patients. We suggest that frequent, postoperative, delayed seizures in MMD are due to the fine angiogenic processes of cortical vessels. Furthermore, this could correlate with surgical modality; that is, SMA with EMS, EDAS, or EDAMS is likely to involve larger areas of angiogenesis than is single SMA. In addition, MMD patients were more frequently treated using these modalities. The 8 patients that experienced delayed seizure underwent the following surgical modalities: 1 case of single SMA, 2 cases of SMA with EDAS, 4 cases of SMA with EMS, and 1 case of SMA with EDAMS. Furthermore, the mean time elapsed between SMA and seizure (mean 16.9±20.0 months) supports this idea of an angiogenic basis.

Hemorrhagic complications appeared more frequently in the MMD than in the ASD group (Table 6-1), but we observed no such significant difference between ASD and MMD patients in the single SMA group. Accordingly, we believe that hemorrhagic complications have a greater correlation to the complexity and duration of surgery than to the disease per se.

Conclusion


The present study suggests that, in both ASD and MMD, the presence of preoperative stroke (infarction) correlated strongly with the postoperative P1ND. In addition, it may also be suggested that complex and protracted surgical modalities may have influences on the incidence of P1ND. Furthermore, we found that only MMD patients experienced delayed seizure attacks after SMA, and we think this may be related to the delayed formation of angiogenesis, which may increase irritation to cortex.


쪱This paper was re-corrected by the author after finding printed errors on October 13, 2010. This correction was reviewed and accepted by the editor.


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