Medication Summary
The goals of pharmacotherapy are to reduce morbidity and prevent complications.
Anticoagulants, Hematologic
Class Summary
Anticoagulants prevent recurrent or ongoing thromboembolic occlusion of the vertebrobasilar circulation. In patients with heparin-induced thrombocytopenia, LVAD implantation has been performed successfully, albeit with additional risk, by using alternative anticoagulants.
Heparin
Heparin may be used if thrombocytopenia is not present. Heparin augments the activity of antithrombin III and prevents the conversion of fibrinogen to fibrin. It does not actively lyse but is able to inhibit further thrombogenesis. Heparin prevents the recurrence of a clot after spontaneous fibrinolysis.
Heparin is routinely given to prevent thrombosis at the site of sheath insertion. The amount used ranges from 40-70 U/kg, depending on the duration and degree of vascular intervention required. Heparin may be administered either via the arterial sheath or intravenously (IV). When given intra-arterially, it is often diluted with the patient's own blood, which can be extracted from the sidearm.
Vasodilators
Class Summary
Vasodilators dilate the mesenteric arterial system. Thereby, they reverse reactive arterial vasospasms. They may be administered during sheath advancement through the guide wire, after completion of the procedure but before removal of the radial sheath, or both.
Papaverine
Papaverine is a benzylisoquinoline derivative that exerts a direct nonspecific relaxant effect on vascular, cardiac, and other smooth muscle. In the absence of peritoneal signs, it is the drug of choice for acute myocardial infarction (AMI) of arterial origin if angiography indicates good distal perfusion. Papaverine is advocated for the treatment of the widespread vasoconstriction that follows therapy for superior mesenteric artery (SMA) emboli by other modalities.
Nitroglycerin (Nitro-Dur, Nitro-Bid, Nitrolingual, Nitrostat)
Nitroglycerin produces vasodilator effects on the peripheral veins and arteries.
Cardiovascular, Other
Class Summary
Agents that prevent radial artery spasm may be used.
Adenosine (Adenoscan, Adenocard)
When used in myocardial perfusion, scintigraphy reveals areas of insufficient blood flow. Adenosine increases blood flow and causes coronary vasodilation in normal coronary arteries, while it causes little or no increase in stenotic coronary arteries. Adenosine is also a short-acting agent that alters potassium conductance into cells and results in hyperpolarization of nodal cells.
Calcium Channel Blockers
Class Summary
Calcium channel blockers are used to prevent radial artery spasm.
Diltiazem (Cardizem, Dilacor XR, Diltzac, Matzim LA)
During depolarization, diltiazem inhibits calcium ions from entering slow channels and voltage-sensitive areas of vascular smooth muscle and myocardium.
Verapamil (Verelan, Calan)
Verapamil relaxes coronary vascular smooth muscle and produces coronary vasodilation.
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Basic setup for insertion of 6-Fr radial sheath.
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Radial artery sheath insertion. Shown are micropuncture needle (above) and cannula-over-needle (below).
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Radial artery sheath insertion. Shown are 5-Fr and 6-Fr radial access sheath with dilator inserted through sheath ready to be used.
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Radial artery sheath insertion. Wrist is positioned by using medical towel. Hyperextension splint may also be used.
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Radial artery sheath insertion. Palpate for radial artery at its expected course.
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Radial artery sheath insertion. Puncture radial artery using either micropuncture needle or cannula-over-needle assembly until flashback of arterial blood is observed.
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Radial artery sheath insertion. Insert guide wire through cannula/micropuncture needle. Once guide wire is sufficiently inserted, cannula/micropuncture needle is removed, leaving guide wire in place.
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Radial artery sheath insertion. Once radial sheath is sufficiently advanced, remove guide wire and dilator.
