[Clinical analysis of cerebral vasospasm following subarachnoid hemorrhage. Part 1 Sequential changes of incidence and degree and its clinical significance (author's transl)]

Early transcranial Doppler after subarachnoid hemorrhage: clinical and radiological correlations

BACKGROUND

The initial decrease in the level of consciousness after subarachnoid hemorrhage (SAH) is commonly considered secondary to cerebral hypoperfusion and metabolic depression. Age, intracranial pressure, and the amount of cisternal blood are closely related to the clinical grade on admission after SAH. Transcranial Doppler (TCD) may partially and indirectly estimate cerebral blood flow through analysis of flow velocity in the middle cerebral artery (MCA). Besides, pulsatility index (PI) can also be considered an indirect estimator of cerebrovascular resistance. The objective of this study was to determine the TCD parameters in the early stage after SAH and to analyze their correlation with the main clinical and radiological variables on admission.

METHODS

A series of 52 consecutive patients diagnosed with SAH, with an abnormal computed tomography (CT) scan on admission and a TCD performed in the first 24 hours from the onset of the hemorrhage, were retrospectively reviewed. Age, sex, clinical grade, presence of cisternal blood or hydrocephalus on initial CT scan, and parameters of TCD examination were recorded for every patient. The relationship between sonographic and clinical and radiological variables was evaluated by partial correlation test, Kruskal-Wallis, and Student t test for paired samples.

RESULTS

There were no significant differences in blood flow velocities or PIs between the left and right sides. Lower velocities and higher PIs correlated with a worse clinical condition at admission. Lower velocities also correlated with larger amounts of cisternal blood on the initial CT scan. No significant correlation was observed between PI and the amount of blood in the initial CT scan.

CONCLUSIONS

A global decrease in blood velocity in the MCA along with a rise in PI is present in the first 24 hours after SAH. These changes correlate with the clinical deterioration and partially with the amount of blood in the initial CT scan. These findings support the hypothesis that low cerebral perfusion caused by high intracranial pressure leads to diffuse ischemic changes in the early phase of SAH.

Detection of delayed cerebral vasospasm, after rupture of intracranial aneurysms, by magnetic resonance angiography

OBJECTIVE

The goal of this study was to assess the value of magnetic resonance angiography (MRA), compared with conventional angiography, in the diagnosis and follow-up monitoring of delayed cerebral vasospasm after subarachnoid hemorrhage resulting from rupture of intracranial aneurysms.

METHODS

For 32 patients undergoing examination by both MRA and conventional angiography during the period of risk for vasospasm, on the same day, the frequency and severity of and sequential changes in vasospasm were evaluated. The three-dimensional time-of-flight method was used. MRA was performed three times, i.e., before, during, and after the period of risk for vasospasm. Conventional angiography was performed twice, i.e., at admission and during the period of risk for vasospasm. Vasospasm was assessed at 22 regions of the cerebral arteries, including the bilateral anterior cerebral (A1, A2, and A3 segments), middle cerebral (M1, M2, and M3 segments), internal carotid (C1 and C2 segments), posterior cerebral (P1 and P2 segments), and posterior communicating arteries.

RESULTS

Seven patients were excluded because of poor MRA images. Twenty-two of 25 patients (125 arteries) showed vasospasm in conventional angiograms. Nineteen of the 22 patients also showed vasospasm in MRA images; however, 57 arteries (45.6%) were diagnosed as showing vasospasm by MRA, and 59 (47.2%) could not be evaluated because of artifacts. For the remaining three patients (nine arteries, 7.2%), vasospasm could not be detected by MRA. Sequential changes in vasospasm could be well evaluated by MRA.

CONCLUSION

MRA could be useful for management of cerebral vasospasm, although it cannot become a practical alternative to conventional angiography.

Aneurysmal rupture during angiography

The aim of the present study was to analyze the clinical data on rebleeding in cerebral aneurysms during angiography and to evaluate the importance of the time interval between the latest rupture and angiography. Fourteen personal cases and 202 patients reported in the literature are reviewed. Rebleeding during angiography occurred most often (78%) on Day O; 89% bled when angiography was performed within 6 hours of the latest rupture. The prognosis in such ruptures was poor, with a mortality of 79%. Intentional delay in angiography of at least 6 hours from the latest rupture is recommended if the associated hematoma is not large.

Cerebral vasospasm in elderly patients with ruptured intracranial aneurysms

Cerebral vasospasm in elderly patients who were operated on the acute stage after subarachnoid hemorrhage was studied under strict criteria. The 138 patients were classified into three age groups: 59 years or younger (group A: 73 cases), 60 to 69 years (group B: 37 cases), and 70 years or older (group C: 28 cases). Severity of both the subarachnoid hemorrhages on computed tomography scan and the angiographic vasospasms was graded. The angiographic vasospasms were analyzed at the internal carotid artery, M1 segments of the middle cerebral artery, and A2 segments of the anterior cerebral. In all the relationships among the subarachnoid hemorrhage grades, the Hounsfield numbers, and the operative approaches to the angiographic vasospasm grade, there was a tendency for the angiographic vasospasm grades to be lower with increasing age in both the internal carotid artery and the M1 segment of the middle cerebral artery. This tendency was more apparent in the larger vessels, that is, the internal carotid arteries. Close correlations of the angiographic vasospasm grades to the incidences of symptomatic vasospasm and to low-density area on computed tomography scan were found in both the M1 and A2 territories in the three groups. However, there were no significant differences among the three groups in the incidences of symptomatic vasospasm and low-density area on computed tomography scan. Regarding the surgical outcome, the older the patients, the higher were the mortality rates: 8% in group A, 11% in group B, and 25% in group C.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiographic vasospasm and release of platelet thromboxane after subarachnoid hemorrhage

We studied adenosine diphosphate-induced platelet aggregation and the associated release of thromboxane B2 in 49 patients with subarachnoid hemorrhage in relation to angiographic vasospasm. Postoperative cerebral angiography was performed less than or equal to 3 (median 1) days after surgery for an aneurysm 5-14 days after subarachnoid hemorrhage. Correspondingly, one sample from each patient was taken within 24 hours either before or after angiography. The occurrence of severe as well as diffuse, moderate, or severe angiographic vasospasm was associated with the presence of delayed cerebral ischemia (p less than 0.05). Patients with diffuse angiographic vasospasm had significantly higher (p less than 0.05) values for thromboxane B2 release than the others, even after adjustment by the clinical grades on admission and before surgery, the timing of surgery, the time from subarachnoid hemorrhage to angiography and blood sampling, and nimodipine therapy. Severe and diffuse angiographic vasospasm were also associated with poor outcome at 1 year (p less than 0.05). Our results suggest that augmented release of platelet thromboxane may be involved in the pathogenesis of vasospasm in large cerebral arteries.

Effect of early operation on cerebral vasospasm

The effect of early operation on cerebral vasospasm was studied in 150 patients with aneurysmal subarachnoid hemorrhages who fulfilled all of the following criteria: admission by day 2 after subarachnoid hemorrhage, no rebleeding, clinical grades I to IV on admission, subarachnoid hemorrhage alone on computed tomography scan, not operated on between days 4 and 20, and availability of bilateral carotid angiograms done by day 2 and redone between days 7 and 9. The patients were divided into two groups: those operated on by day 3 (group 1: 116 patients) and those operated on after day 20 or not operated on (group 2: 34 patients). Severity of both subarachnoid hemorrhage on computed tomography scan and angiographic vasospasm were graded into 0-IV. Angiographic vasospasm was observed in 95% of group 1 and in 88% of group 2 patients. A significant difference could not be found between groups 1 and 2 in the angiographic vasospasm grades. The incidence of symptomatic vasospasm in group 1 was 18%, which was significantly lower than the 44% in group 2. In group 1 patients with subarachnoid hemorrhage grades II to III, the incidences of symptomatic vasospasm and low density area on computed tomography scan were 13% and 10%, respectively. Both of these rates were significantly lower than those in group 2, which were 50% and 36%, respectively. However, in patients with subarachnoid hemorrhage grade IV, no differences could be found between groups 1 and 2. There was a close correlation between the angiographic vasospasm grades and the incidence of symptomatic vasospasm in group 1. However, in group 1, no correlation could be observed between the site of ruptured aneurysms or the timing of operations and vasospasm. Although there is still a limit to the effect of early operation on cerebral vasospasm in patients with subarachnoid hemorrhage grade IV, symptomatic vasospasm after subarachnoid hemorrhage may be ameliorated by early operation in patients with subarachnoid hemorrhage grades II to III.