Vasospasm

Fig. 13.1

Left vertebral angiogram demonstrating vasospasm of basilar artery. Flow restriction because of the vasospasm is demonstrated by the significant contrast reflux into the right vertebral artery (VA). The spasm of the basilar artery has resulted in the caliber of this vessel appearing smaller than that of the VAs. In addition to caliber, vasospasm is also diagnosed by observing the caliber of the affected vessel at termination, i.e., where it branches. A vessel in vasospasm will appear bulbous or of a larger caliber at termination. By contrast, a congenitally hypoplastic or stenosed vessel does not demonstrate this bulbosity

Vasospasm secondary to mechanical manipulation.

Preoperative Management

The aneurysm should be secured by clipping or coiling prior to pharmacological or endovascular management of vasospasm.
Ensure the MAP is ≥70 mmHg.
Preoperative intubation, if there are any concerns about the patient’s ability to protect airway.
Verify laboratory values including platelet count, BUN, CR, APTT, PT/INR, and ß-HCG for females of reproductive age group.
In case of renal insufficiency, diabetes, CHF, etc., ensure usage of diluted non-ionic contrast agent and carefully pre-plan to maintain contrast load to minimum.
NPO (for ≈6 h) when procedure is to be performed under general anesthesia.
Obtain informed consent for angiography and angioplasty.
Ensure two IV lines inserted.
Insert Foley. Patient will be more comfortable and cooperative with an empty bladder in case the procedure becomes prolonged.
Position patient on neuroangiography table.
Attach patient to pulse oximetry and ECG leads for monitoring O₂ saturation, HR, cardiac rhythm respiratory rate, and BP.

Technique

After the groin region is appropriately prepped and draped, palpate the femoral artery.
Immobilize a segment of the artery between the index and middle fingers.
Infiltrate the skin overlying the immobilized segment with local anesthesia using 1% lidocaine with epinephrine.
Make a small, superficial stab incision in the anesthetized skin.
Using modified Seldinger technique, perform an arteriotomy (see Chap. 2 for technique for arteriotomy and sheath placement) and make an exchange over wires to place a sheath in the femoral artery.
The sheath should be ≥6 Fr, just in case a procedure such as angioplasty needs to be performed.
The sheath is connected to a continuously running flush of heparinized saline.
Connect a diagnostic catheter (e.g., 5 Fr Glidecath) to a continuously running flush of heparinized saline.
Introduce a 0.035 glidewire into the catheter.
Ensure that sheath and catheter systems are free of air, or any other foreign bodies.
Once the catheter is in the sheath, advance it over the wire using fluoroscopy.
If the patient’s vasculature is anticipated to be non-tortuous, consider using a Guide catheter, e.g., 6 Fr Envoy instead of the diagnostic catheter. It will save the time required for exchanging the diagnostic catheter for a guide catheter, in case intervention is decided upon.
During diagnostic angiography esp. when using a guide catheter, when a vasospastic segment is identified, it is best to treat it at least chemically before proceeding to the next vessel. It may save some time by eliminating the need to catheterize the same artery more than twice.
Study the vasculature most at risk of vasospasm first based on history (i.e., if location of an aneurysm is known), symptomatology and studies such as TCD’s. We usually also perform a CT perfusion study to assess whether or not angiography or intervention is warranted.

Selective Intra-arterial Pharmacological Intervention

The guide catheter is securely positioned in the pertinent artery of the neck (Carotid or vertebral depending upon the intracranial vessel being treated).
A microcatheter (e.g., Excelsior SL 10 with transcend 0.010 or 0.014 guidewire) is prepared.
The microcatheter is connected to a continuously running flush of heparinized saline.
It is ensured that the entire system is free of air or any other foreign matter.
Advance the microcatheter with contained microwire into the RHV of the guide catheter.
Advance the microcatheter over the microwire until both reach the distal tip of the guide catheter.
Perform a roadmap.
With the help of roadmap guidance, advance the microcatheter over the microwire to position the catheter tip just distal to the segment in spasm.
Remove the microwire.

Verapamil

Indicated for mild non-flow limiting vasospasm that does not warrant angioplasty or moderate vasospasm that cannot be safely treated with angioplasty.
It may also be indicated in those who have vasospasm consequent to manipulation during endovascular intervention.
We also use it prior to performing angioplasty, so that the dilatation is performed on the relaxed dilated artery rather than a relatively rigid vasoconstricted artery.
Verapamil is our agent of first choice. We have found it to be safe and effective to the extent that, we use it almost exclusively.

Dose: 5–10 mg is injected gradually (over 2–10 min) as the microcatheter is withdrawn through the spasmodic segment. Up to 20 mg may be given into each arterial tree. Inject gradually to ensure there is no significant drop in BP or bradycardia.

Alternatively, verapamil injection is frequently performed through the diagnostic or guide catheter positioned further proximally in internal carotid artery (ICA), or VA. This approach has the significant advantage of being quicker and bypasses the complexities of using a microcatheter. However, the amount of verapamil reaching the spastic segment may be less.

Contraindications

Acute MI, severe CHF, cardiogenic shock, severe hypotension, second or third degree AV block, sick sinus syndrome, marked bradycardia, hypersensitivity to the drug, Wolff–Parkinson–White syndrome, Lown–Ganong–Levine syndrome.

Nicardipine

Nicardipine is diluted with normal saline to a concentration of 0.1 mg/ml and administered in 1-ml aliquots to a maximum dose of 5 mg per vessel.
Similar to verapamil administration above, administer gradually as the catheter is withdrawn through the spastic segment of the vessel. Gradual administration will also attenuate the likelihood of untoward side effects, e.g., transient tachycardia, hypotension or, increased intracranial pressure (ICP).

Contraindications

Hypersensitivity to the drug.
Aortic stenosis.

Papavarine

It is a short acting, with a half life of less than 1 h.
It may be used for cerebral vasospasm. However, due to the short duration of action other agents, e.g., verapamil are preferable.
Papavarine may be used for angioplasty pre-treatment to enable placement of balloon catheter by causing vasodilatation.

Dose: Available in 3% concentration (30 mg/ml) at pH 3.3. 300 mg of Papaverine is diluted in 100 ml of normal saline to obtain a 0.3% concentration.