Vascular Access and Catheter Directed Angiography

Question 1

When is catheter-based diagnostic angiography usually performed?

Answer 1

Catheter-based diagnostic angiography is most commonly performed either when there is intention to proceed to endovascular intervention or when computed tomography (CT) or magnetic resonance angiography (MRA) is nondiagnostic or not possible

Question 2

What are other indications of catheter-based angiography (5)

Answer 2

1. As part of percutaneous endovascular procedures (e.g., thrombolysis, balloon angioplasty, atherectomy, thrombectomy, stenting, embolization, infusion of pharmaceuticals)
2. Diagnosis of primary vascular disease (e.g., vascular occlusive disease, vasculitis, vasospastic disorders, aneurysms, arteriovenous [AV] malformations, AV fistulas) 3. Vascular complications of trauma, surgery, or disease
3. Preprocedural definition of vascular anatomy (e.g., for revascularization procedures, local tumor resection, organ transplantation, complex embolization, assessment of arterial hemorrhage)
4. Diagnosis and localization of vascular tumors (e.g., parathyroid adenomas, pancreatic neuroendocrine tumors)

Question 3

Absolute contraindication of catheter-based angiography

Answer 3

Medically unstable patient with multisystem dysfunction

(If angiography is absolutely necessary, underlying abnormalities should be corrected and preventive measures against anticipated complications should be taken.)

Question 4

Relative contraindications of catheter-based angiography (9)

Answer 4

1. Recent myocardial infarction, serious arrhythmia, and substantial serum electrolyte imbalance
2. Serious documented past contrast reaction
3. Impaired renal status. Consider prehydration or CO2 angiography.
4. Uncooperative patient (consider general anesthesia)
5. Coagulopathies or seriously altered coagulation profile
6. Inability to lie flat on angiography table due to congestive heart failure or compromised respiratory status
7. Residual barium in abdomen from recent examination (will obscure details of visceral angiography)
8. Pregnancy, because of risk of exposure of fetus to ionizing radiation
9. Ehlers–Danlos syndrome (high risk of arterial injury, dissection)

Question 5

Management for heparinize patient?

Answer 5

Stop heparin infusion 2 hours prior to the arterial puncture in order to normalize the coagulation status.

A PTT of 1.2 times control is acceptable, in the absence of other bleeding abnormalities.

Heparin may be restarted within 2 to 4 hours after removal of the catheter for manual puncture-site compression or sooner in selected cases (e.g., patients for whom an arterial puncture closure device was used or venous catheterizations).

For patients getting therapeutic dose injections of low- molecular-weight heparin, the dose prior to the procedure is held.

Question 6

How many days to stop warfarin?

Answer 6

Stop warfarin 3 to 5 days prior to arterial puncture if possible.

(SLMC 5 days)

Question 7

What medication may be given for hospitalized warfarinized patients with persistently elevated INR and nonurgent indications for angiography?

Answer 7

Vitamin K (2 to 10 mg) may be administered either orally 24 to 48 hours preprocedure

Or

Intravenously (IV) 12 to 24 hours preprocedure with serial monitoring of the INR for reversal

Question 8

What management should be done for hospitalized warfarinized patients with nonurgent or emergent basis?

Answer 8

Patients who require procedures on an urgent or emergent basis should be treated with short-acting products to reverse anticoagulation, such as

Fresh frozen plasma (FFP),
Prothrombin complex concentrate (PCC),
Recombinant factor VIIa, or
activated PCC.

The goal is to achieve an INR of 1.5 or less.

Question 9

If discontinuation of warfarin is unacceptable. What other options are possible?

Answer 9

For patients in whom discontinuation of anticoagulation is unacceptable (e.g., metal prosthetic heart valve), warfarin can be stopped and anticoagulation may be transitioned with low-molecular-weight heparin as an outpatient, or the patient may be admitted for transition with IV heparin.

Question 10

New oral anticoagulant medications

Answer 10

Dabigatran (direct thrombin inhibitor)
Rivaroxaban and Apixaban (direct factor Xa inhibitors)

Question 11

Half-lives of dabigatran, rivaroxaban, and apixaban

Answer 11

Relatively short half-lives (<14 hours)

Question 12

When should dabigatran, rivaroxaban, and apixaban be discontinued?

Answer 12

Discontinuation for 1 to 2 days prior to arterial puncture is usually sufficient

(Longer in patients with renal disease, since these drugs are cleared by kidneys)

Question 13

What are examples of antiplatelet agents?

Answer 13

Aspirin, clopidogrel, and glycoprotein (GP) IIb/IIIa inhibitors

Question 14

When should antiplatelets be discontinued?

Answer 14

Guidelines recommend discontinuation as follows

(5 to 7 days for clopidogrel, 8 to 48 hours for GP IIb/ IIIa inihibitors)

Question 15

Cases with emergency procedure with ongoing antiplatelet. What is another form of management?

Answer 15

Platelet transfusion for emergency cases

Question 16

What should be the functional platelet count undergoing transfemoral or transaxillary puncture?

Answer 16

Should be greater than 50,000 per uL

Question 17

How to manage insulin-dependent diabetic patient undergoing transfemoral arterial puncture?

Answer 17

Cut the morning insulin dose by half and schedule the procedure for the morning if possible.

Slow infusion of 5% dextrose may be started prior to the procedure, and volume expansion with IV fluids is indicated to prevent contrast-induced nephropathy.

Blood glucose levels should be monitored during prolonged procedures; insulin dose may need to be titrated before resumption of usual regimen.

Question 18

What is the management if a diabetic patient on neutral protamine Hagedorn (NPH) insulin receives heparin during the procedure.

Answer 18

Do not reverse the heparin with protamine sulfate because this may cause fatal anaphylactic reaction.

Restart normal insulin schedule after the procedure once the patient has resumed oral intake.

Question 19

Alternative management for patients who have documented reaction to iodinated contrast media

Answer 19

Consider gadolinium-enhanced MRA for patients without renal insufficiency.

Carbon dioxide arteriography, intra-arterial pressure measurements, and duplex scan (Infrainguinal) arterial mapping may aid diagnosis in selected patients.

Question 20

Most angiography and interventional procedures can be completed safely and expeditiously with a judicious combination of what medications?

Answer 20

Midazolam and fentanyl

They provide adequate conscious sedation and analgesia

Question 21

Medication precaution for elderly patients

Answer 21

Reduce medication doses by 30% to 50% for elderly patients

Question 22

Consideration for a patient with pheochromocytoma

Answer 22

Patients with labile blood pressure need alpha blockade (phenoxybenzamine)

Consider consulting an anesthesiologist for the procedure.

Short-acting agents, such as sodium nitroprosside, should be available for treating potential hypertensive crisis.

Avoid the use of glucagon in patients with suspected pheochromocytoma.

Question 23

Patients with sickle cell anemia and polycytemia vera may suffer what complication after angiography?

Answer 23

Thromboembolic complications

Question 24

Consideration for patients with neuroendocrine tumors

Answer 24

Carcinoid crisis can be stimulated by angiography on patients with neuroendocrine metastases to the liver.

Consider pretreatment with IM ocreotide and have ocreatide drip available.

Question 25

Should all patients undergoing angiographic or interventional procedure with conscious sedation should have continuous physiologic monitoring?

True or False

Answer 25

True

Question 26

Induce how many percentage of lidocaine in the puncture site for retrograde femoral artery cathterization?

Answer 26

1% or 2% Lidocaine (without epinephrine)

Question 27

In order to minimize the burning sensation of lidocaine. What medication should be added?

Answer 27

Consider the addition of 1 mL sodium bicarbonate 8.4% in the syringe with each 10 mL of lidocaine to minimize the burning sensation during injection.

Question 28

Steps on injecting lidocaine (3)

Answer 28

1. Skin wheal at the entry site (using 25 gauge, 4/8 inch needle) and deep on each side of the artery in an inverted cone distribution (using 22- to 25 gauge, 1.5 inch needle)
2. Avoid entering the artery or vein and injecting lidocaine into the vessel wall by gentle aspiration as the needle is advanced, and injection of anesthetic upon needle withdrawal. Slow, gentle injection will save the patient considerable discomfort. Wait 1 to 2 minutes after injection before making a superficial skin incision (3 mm long x 3 mm deep) with a no. 11 blade scalpel
3. Use a curved 5- in mosquito forceps to spread the subcutaneous tissues; avoid spreading down to the artery. Adequate dissection of subcutaneous tissues in this manner facilitates subsequent passage of catheters and sheaths, enables egress of blood at the skin rather than internally, and is also important when considering use of an arterial closure device to allow the device to tract easily to the arteriotomy site

Question 29

How to identify the true position of the inguinal ligament?

Answer 29

The true position of the inguinal ligament is about 1 to 2 cm below the location estimated by palpation or fluoroscopy

Question 30

A high arterial entry may lead to what problem?

Answer 30

Cannot be adequately compressed and may lead to uncontrollable internal bleeding.

Question 31

A low arterial entry may lead to what problem?

Answer 31

May result in pseudoaneurysm of the superficial femoral artery.