Per-operative cerebral angiography

Comparing indocyanine green videoangiography to the gold standard of intraoperative digital subtraction angiography used in aneurysm surgery

Object

The purpose of aneurysm surgery is complete aneurysm obliteration while sparing associated arteries. Indocyanine green (ICG) videoangiography is a new technique that allows for real-time evaluation of blood flow in the aneurysm and vessels. The authors performed a retrospective study to compare the accuracy of ICG videoangiography with intraoperative angiography (IA), and determine if ICG videoangiography can be used without follow-up IA.

Methods

From June 2007 through September 2009, 155 patients underwent craniotomies for clipping of aneurysms. Operative summaries, angiograms, and operative and ICG videoangiography videos were reviewed. The number, size, and location of aneurysms, the ICG videoangiography and IA findings, and the need for clip adjustment after ICG videoangiography and IA were recorded. Discordance between ICG videoangiography and IA was defined as ICG videoangiography demonstrating aneurysm obliteration and normal vessel flow, but post-IA showing either an aneurysmal remnant and/or vessel occlusion requiring clip adjustment.

Results

Thirty-two percent of patients (49 of 155) underwent both ICG videoangiography and IA. The post-ICG videoangiography clip adjustment rate was 4.1% (2 of 49). The overall rate of ICG videoangiography–IA agreement was 75.5% (37 of 49) and the ICG videoangiography–IA discordance rate requiring post-IA clip adjustment was 14.3% (7 of 49). Adjustments were due to 3 aneurysmal remnants and 4 vessel occlusions. These adjustments were attributed to obscuration of the residual aneurysm or the affected vessel from the field of view and the presence of dye in the affected vessel via collateral flow. Although not statistically significant, there was a trend for ICG videoangiography–IA discordance requiring clip adjustment to occur in cases involving the anterior communicating artery complex, with an odds ratio of 3.3 for ICG videoangiography–IA discordance in these cases.

Conclusions

These results suggest that care should be taken when considering ICG videoangiography as the sole means for intraoperative evaluation of aneurysm clip application. The authors further conclude that IA should remain the gold standard for evaluation during aneurysm surgery. However, a combination of ICG videoangiography and IA may ultimately prove to be the most effective strategy for maximizing the safety and efficacy of aneurysm surgery.

Completion angiography for surgically treated cerebral aneurysms: an economic analysis

OBJECTIVE

To compare cost-effectiveness of different strategies for completion angiography after cerebral aneurysm clipping.

METHODS

A literature search was used to determine the outcome probabilities and costs of various strategies. The pooled results were used in a Markov cost-effectiveness model to compare quality-adjusted life-years and costs of each strategy. Sensitivity (threshold) analyses and Monte Carlo simulation were used to test variation in the model.

RESULTS

Routine (for all cases) intraoperative angiography proved to be slightly more cost-effective than selective (only for cases deemed "high risk") intraoperative angiography, being both less costly and more effective. Routine postoperative angiography was the least cost-effective. However, in centers whose rates of clip-induced arterial compromise are much lower than the averages reported in the literature, selective angiography might be warranted.

CONCLUSION

Routine intraoperative angiography remains the most cost-effective form of completion angiography after aneurysm clipping, at least at our present state of technology.

Is routine intraoperative angiography in the surgical treatment of cerebral aneurysms justified? A consecutive series of 147 aneurysms

OBJECTIVE

The role of intraoperative angiography (IA) in the surgical treatment of cerebral aneurysms has remained extremely controversial. We determine the frequency and predictors of unanticipated findings necessitating clip adjustment established on postoperative angiography (PA) in a consecutive series of 147 aneurysms. On the basis of published series, we discuss the utility, safety, accuracy, and cost effectiveness of adjunct IA in the surgical treatment of cerebral aneurysms.

METHODS

We retrospectively examined the charts of 124 consecutive patients harboring 147 aneurysms that were surgically clipped between December 2000 and March 2005 and had PA available for review. Patient demographics, aneurysm size, location, Hunt and Hess score, Fisher grade, mode of aneurysm discovery, time between discovery and surgery, and PA results, as determined by a blinded independent neuroradiologist, were recorded.

RESULTS

PA demonstrated two (1.4%) unexpected residuals, four anticipated residuals (2.7%), and four (2.7%) vessel compromises. Of the six unanticipated outcomes, two of two (100%) unexpected residuals and three of four (75%) vessel compromises were from large aneurysms (P = 0.0001 each). Middle cerebral artery aneurysms comprised 5 of 10 (50%) imperfect outcomes (three expected remnants and two vessel occlusions), which trended toward significance (P = 0.06).

CONCLUSION

IA is recommended during the surgical clipping of complex or large aneurysms and some middle cerebral artery aneurysms. High cost-benefit ratio, false-negative rate, and moderate risk, however, preclude routine use. With future technological advances, IA may warrant broader use by replacing postoperative studies in the neurosurgical management of intracranial aneurysms.

Intraoperative Cerebral Angiography: Superficial Temporal Artery Method and Results

OBJECTIVE

To report the method for and results of intraoperative cerebral angiography performed via the superficial temporal artery, for assessment of cerebral aneurysm surgery.

METHODS

All patients undergoing craniotomies for treatment of intracranial aneurysms were prospectively entered into a database. A policy of performing angiography via the superficial temporal artery in appropriate cases was instituted. This procedure was performed with retrograde catheterization of the superficial temporal artery, as it coursed over the zygomatic arch, with an 18-gauge, 1.88-inch, intravenous catheter and hand injection of contrast material, with intraoperative digital subtraction fluoroscopic guidance.

RESULTS

Thirty-six patients who underwent 38 craniotomies for clipping of 43 aneurysms underwent intraoperative angiography via the superficial temporal artery. There were six unexpected findings (14%), including four unexpected arterial occlusions and two unexpected residual aneurysms. One aneurysm was observed to be patent when it was punctured, after intraoperative angiography had indicated no filling of the aneurysm. Additional clips were placed. Three patients (8%) developed multiple arterial infarctions in the territory of the injected carotid artery, for which multiple causes were possible. Adequate angiographic images could usually be obtained with this method.

CONCLUSION

Intraoperative angiography via the superficial temporal artery is simple and is not associated with substantial complications. It is a reasonable alternative to transfemoral angiography for detection of adverse consequences of intracranial aneurysm clipping.

Intraoperative endovascular treatment as an adjunct to microsurgical clipping of paraclinoid aneurysms

OBJECT

The endovascular procedure can provide proximal control, suction decompression, and prompt intraoperative angiography during microsurgical clipping of aneurysms of the paraclinoid segment of the internal carotid artery (ICA). The authors assess the safety and feasibility of this method in 24 consecutive cases.

METHODS

Frontotemporal craniotomy and radical pterionectomy were performed with the patient's head immobilized in a radiolucent frame while femoral artery catheterization was achieved. Before dural opening, a balloon catheter with a coaxial lumen was positioned and tested in the ICA, after which microsurgical exposure was completed, including intradural clinoid drilling and optic canal decompression. Trapping of the lesion was achieved by inflating the balloon and placing a temporary clip beyond the aneurysm neck. The catheter was gently aspirated to achieve suction decompression and to facilitate clip application. Intraoperative digital subtraction angiography was then performed. Twenty-two aneurysms were larger than 10 mm, and 11 of them were giant. Six patients presented with subarachnoid hemorrhage and nine with visual symptoms. Balloon occlusion and suction decompression were performed in 16 cases (67%), and proximal control alone in 1 case. Intraoperative angiography was performed in every case. Subsequent clip readjustment was necessary in seven cases, including three cases of residual aneurysm filling and four of ICA compromise. Complete aneurysm obliteration was achieved in 20 cases, and greater than 90% obliteration in 22. One major infarct likely related to catheter thromboembolism was found. There were no instances of visual deterioration or other complications attributable to the endovascular procedure.

CONCLUSIONS

The endovascular method allows safe and reliable proximal control, suction decompression, and intraoperative angiography in microsurgical treatment of large paraclinoid aneurysms.

Intraoperative angiography in cerebral aneurysm surgery: a prospective study of 100 craniotomies

OBJECTIVE

To determine the frequency of unexpected major arterial occlusion and incomplete aneurysm clipping on intraoperative angiography after cerebral aneurysm clipping and to determine factors that predict these unexpected findings.

METHODS

Data was collected prospectively on 100 consecutive craniotomies for the clipping of 107 aneurysms in 92 patients. Patient age and sex, aneurysm location and size, how the aneurysm presented, day of surgery after hemorrhage, intraoperative rupture, and postoperative course were recorded. After clipping, the surgeon recorded whether he thought the aneurysm was obliterated and whether he thought the clip occluded a major artery. Intraoperative angiography was then performed. The incidence of unexpectedly finding a major arterial occlusion or residual aneurysm was determined. Factors predicting these unexpected findings revealed by intraoperative angiography were identified by logistic regression.

RESULTS

There were 11 giant (10%), 13 posterior circulation (12%), and 68 (64%) ruptured aneurysms. Unexpected angiographic findings necessitating at least one clip adjustment occurred in 12 cases (11%). Clip readjustments restored flow through six major arterial occlusions (6%) and completely obliterated 10 persistently filling aneurysms (10%). Logistic regression showed that factors predicting an unexpected arterial occlusion were giant aneurysm and basilar apex location (P < 0.05). Unexpected residual aneurysm was predicted by giant aneurysm and posterior communicating artery location (P < 0.05).

CONCLUSION

Intraoperative angiography detects unexpected arterial occlusions and residual aneurysms in 12% of cases and can decrease complications of aneurysm surgery, although the yield in unselected patients is low. The subgroup of patients with giant, basilar apex, and posterior communicating artery aneurysms has a significantly higher incidence of untoward findings and may benefit from increased usage of intraoperative angiography.

An investigation with serial angiography into the evolution of cerebral arterial spasm following aneurysm surgery

Serial postoperative angiograms were performed in 28 patients with intracranial aneurysms, 26 of whom had presented with a subarachnoid hemorrhage. The clinical state and intracranial pressure (ICP) were also measured. Angiograms were performed in the ward using a cannula, which was passed into the proximal external carotid artery via the superficial temporal artery. Measurements of the vessel diameters were made, with the preoperative angiogram as a baseline. Patients could be placed into one of five groups depending on the presence or absence of significant arterial spasm, the clinical state of the patient, and the normality or otherwise of the ICP. No patient's condition deteriorated without an elevated ICP and/or significant arterial spasm. The study shows that this spasm is usually associated with a poor clinical state if it reaches a maximum 8 to 12 hours after the operation, although the clinical deterioration is not apparent for a further 6 to 12 hours. Knowledge of the natural history of postoperative arterial spasm may allow earlier treatment of the spasm, which may be more successful than delaying treatment until clinical deterioration has occurred. The worth of the varied drugs proposed for the treatment of spasm may be assessed using this type of protocol.