Automated, compliant, high-flow common carotid to middle cerebral artery bypass

National trends in cerebral bypass surgery in the United States, 2002–2014

OBJECTIVE

Cerebral bypass procedures are microsurgical techniques to augment or restore cerebral blood flow when treating a number of brain vascular diseases including moyamoya disease, occlusive vascular disease, and cerebral aneurysms. With advances in endovascular therapy and evolving evidence-based guidelines, it has been suggested that cerebral bypass procedures are in a state of decline. Here, the authors characterize the national trends in cerebral bypass surgery in the United States from 2002 to 2014.

METHODS

Using the National (Nationwide) Inpatient Sample, the authors extracted for analysis the data on all adult patients who had undergone cerebral bypass as indicated by ICD-9-CM procedure code 34.28. Indications for bypass procedures, patient demographics, healthcare costs, and regional variations are described. Results were stratified by indication for cerebral bypass including moyamoya disease, occlusive vascular disease, and cerebral aneurysms. Predictors of inpatient complications and death were evaluated using multivariable logistic regression analysis.

RESULTS

From 2002 to 2014, there was an increase in the annual number of cerebral bypass surgeries performed in the United States. This increase reflected a growth in the number of cerebral bypass procedures performed for adult moyamoya disease, whereas cases performed for occlusive vascular disease or cerebral aneurysms declined. Inpatient complication rates for cerebral bypass performed for moyamoya disease, vascular occlusive disease, and cerebral aneurysm were 13.2%, 25.1%, and 56.3%, respectively. Rates of iatrogenic stroke ranged from 3.8% to 20.4%, and mortality rates were 0.3%, 1.4%, and 7.8% for moyamoya disease, occlusive vascular disease, and cerebral aneurysms, respectively. Multivariate logistic regression confirmed that cerebral bypass for vascular occlusive disease or cerebral aneurysm is a statistically significant predictor of inpatient complications and death. Mean healthcare costs of cerebral bypass remained unchanged from 2002 to 20014 and varied with treatment indication: moyamoya disease $38,406 ± $483, vascular occlusive disease $46,618 ± $774, and aneurysm $111,753 ± $2381.

CONCLUSIONS

The number of cerebral bypass surgeries performed for adult revascularization has increased in the United States from 2002 to 2014. Rising rates of surgical bypass reflect a greater proportion of surgeries performed for moyamoya disease, whereas bypasses performed for vascular occlusive disease and aneurysms are decreasing. Despite evolving indications, cerebral bypass remains an important surgical tool in the modern endovascular era and may be increasing in use. Stagnant complication rates highlight the need for continued interest in advancing available bypass techniques or technologies to improve patient outcomes.

Advances and surgical considerations in the treatment of moyamoya disease

Moyamoya is a rare disorder that involves steno-occlusive arterial changes of the anterior circulation, along with proliferative development of basal arterial collaterals. It is either idiopathic (called moyamoya disease) or the result of a specific underlying condition such as atherosclerosis, radiation therapy, or sickle cell disease (called moyamoya syndrome or phenomenon). In recent years, numerous insights into and advances in the understanding, evaluation, and management of moyamoya patients have occurred. This article briefly reviews the spectrum of moyamoya conditions and then provides a synopsis of numerous recent investigations that shed light on various aspects of the disease, including its clinical characteristics, natural history, underlying pathology, imaging, surgical techniques, and long-term patient outcome.

Tissue fusion, a new opportunity for sutureless bypass surgery

Microsurgical suturing is the standard for cerebral bypass surgery, a technique where temporary occlusion is usually necessary. Non-occlusive techniques such as excimer laser-assisted non-occlusive anastomosis (ELANA) have certainly widened the spectrum of treatment of complex cerebrovascular situations, such as giant cerebral aneurysms, that were otherwise non-treatable. Nevertheless, the reduction of surgical risks while widening the spectrum of indications, such as a prophylactic cerebral bypass, is still a main aim, that we would like to pursue with our sutureless tissue fusion research. The primary concern in sutureless tissue fusion- and especially in tissue fusion of cerebral vessels- is the lack of reproducibility, often caused by variations in the thermal damage of the vessel. This has prevented this novel fusion technique from being applicable in daily surgical use. In this overview, we present three ways to further improve the laser tissue soldering technique.In the first section entitled "Laser Tissue Soldering Using a Biodegradable Polymer," a porous polymer scaffold doped with albumin (BSA) and indocyanine green (ICG) is presented, leading to strong and reproducible tensile strengths in tissue soldering. Histologies and future developments are discussed.In the section "Numerical Simulation for Improvement of Laser Tissue Soldering," a powerful theoretical simulation model is used to calculate temperature distribution during soldering. The goal of this research is to have a tool in hand that allows us to determine laser irradiation parameters that guarantee strong vessel fusion without thermally damaging the inner structures such as the intima and endothelium.In a third section, "Nanoparticles in Laser Tissue Soldering," we demonstrate that nanoparticles can be used to produce a stable and well-defined spatial absorption profile in the scaffold, which is an important step towards increasing the reproducibility. The risks of implanting nanoparticles into a biodegradable scaffold are discussed.Step by step, these developments in sutureless tissue fusion have improved the tensile strength and the reproducibility, and are constantly evolving towards a clinically applicable anastomosis technique.

Experimental simplification of the excimer laser-assisted nonocclusive anastomosis (ELANA) technique

BACKGROUND

The excimer laser-assisted nonocclusive anastomosis (ELANA) technique facilitates the construction of an end-to-side anastomosis between a donor vessel and a recipient artery without the need to temporarily occlude the recipient artery.

OBJECTIVE

To test whether the surgically difficult ELANA technique can be simplified.

METHODS

In 42 rabbits, with the aorta as the recipient artery and human saphenous veins as donor grafts, we made 30 conventional ELANAs with 8 microsutures, 90 ELANAs with 4 microsutures (ELANA-4s), 40 ELANAs with 2 microsutures (ELANA-2s), and 90 sutureless ELANAs (SELANAs). SELANA involved a new ring design with 2 pins. ELANA-4, ELANA-2, and SELANA were each combined with 3 different sealants (Bioglue, Tachoseal, and Tisseel) and compared regarding application time, complications, and burst pressure.

RESULTS

The conventional ELANA was constructed in a mean of 14.8 +/- 2.6 minutes. All experimental anastomoses were constructed significantly faster; the ELANA-4 in a mean of 10.9 +/- 1.3 minutes, the ELANA-2 in a mean of 5.4 +/- 1.7 minutes, and the SELANA in a mean of 2.5 +/- 1.8 minutes. All ELANA and ELANA-4 anastomoses were sufficiently strong with a burst pressure > 200 mm Hg, except for 1 insufficiently sealed ELANA-4 anastomosis. ELANA-2 was sufficiently strong only with Bioglue, showing a burst pressure > 280 mm Hg. SELANA was sufficiently strong with Bioglue or TachoSil, showing a burst pressure > 260 mm Hg.

CONCLUSION

The ELANA technique can be simplified by reducing or even abandoning microsutures. Of the experimental anastomoses tested, we consider the SELANA technique combined with TachoSil of most potential benefit. Long-term survival studies will be performed in animals before we consider using any of these new techniques in patients.

Self-closing Nitinol U-Clips for intracranial arterial microanastomosis: a preliminary experience on seven cases

PURPOSE

To report experience on the use of self-closing nitinol U-Clips for different types of intracranial arterial microanastomosis.

METHODS

We treated 7 patients (3 females and 4 males, age ranging from 25 to 68 yo) admitted from November 2005 to January 2008 to the Neurological Institute C. Besta of Milan. One patient had cerebral hypoperfusion and the others a complex intracranial aneurysm. In each patient a bypass procedure was completed by using self-closing Nitinol U-Clips for intracranial arterial microanastomoses.

RESULTS

The total time of temporary occlusion was 15.71 +/- 4.386 min. Bypass patency was confirmed intraoperatively by near-infrared indocyanine green videoangiography and microdoppler in each patient. No spasm of the graft was encountered and immediate post-operative bypass patency was confirmed in 6/7 patients. The graft thrombosed in 1 patient with antiphospholipid syndrome. 1 patient died from a massive Subarachnoid Hemorrhage due to rupture of an aneurysm while waiting for an endovascular procedure. In the 5 patients at the last follow-up, long-term patency of the bypass was confirmed and no neurological deficits occurred related to the procedure.

CONCLUSION

This is the first report of the use of U-Clips for intracranial microanastomosis. Our data indicated that it is a safe technique, reduces the time taken to perform an anastomosis and the risk of an ischemic complication. Further studies of the longer-term patency of bypass as performed with U-Clips are required.

C-Port Flex-A–assisted automated anastomosis for high-flow extracranial-intracranial bypass surgery in patients with symptomatic carotid artery occlusion: a feasibility study

Object

Preliminary experience with the C-Port Flex-A Anastomosis System (Cardica, Inc.) to enable rapid automated anastomosis has been reported in coronary artery bypass surgery. The goal of the current study was to define the feasibility and safety of this method for high-flow extracranial-intracranial (EC-IC) bypass surgery in a clinical series.

Methods

In a prospective study design, patients with symptomatic carotid artery (CA) occlusion were selected for C-Port–assisted high-flow EC-IC bypass surgery if they met the following criteria: 1) transient or moderate permanent symptoms of focal ischemia; 2) CA occlusion; 3) hemodynamic instability; and 4) had provided informed consent. Bypasses were done using a radial artery graft that was proximally anastomosed to the superficial temporal artery trunk, the cervical external, or common CA. All distal cerebral anastomoses were performed on M2 branches using the C-Port Flex-A system.

Results

Within 6 months, 10 patients were enrolled in the study. The distal automated anastomosis could be accomplished in all patients; the median temporary occlusion time was 16.6 ± 3.4 minutes. Intraoperative digital subtraction angiography (DSA) confirmed good bypass function in 9 patients, and in 1 the anastomosis was classified as fair. There was 1 major perioperative complication that consisted of the creation of a pseudoaneurysm due to a hardware problem. In all but 1 case the bypass was shown to be patent on DSA after 7 days; furthermore, in 1 patient a late occlusion developed due to vasospasm after a sylvian hemorrhage. One-week follow-up DSA revealed transient asymptomatic extracranial spasm of the donor artery and the radial artery graft in 1 case. Two patients developed a limited zone of infarction on CT scanning during the follow-up course.

Conclusions

In patients with symptomatic CA occlusion, C-Port Flex-A–assisted high-flow EC-IC bypass surgery is a technically feasible procedure. The system needs further modification to achieve a faster and safer anastomosis to enable a conclusive comparison with standard and laser-assisted methods for high-flow bypass surgery.