Should patients receiving a radial artery conduit have post-operative calcium channel blockers?

Area of Science:

• Cardiac Surgery
• Vascular Grafting
• Pharmacology

Background:

• Radial artery grafts are frequently used in coronary artery bypass grafting (CABG).
• Routine administration of calcium channel blockers (CCBs) and nitrates is common practice to prevent graft vasospasm.
• The necessity of these medications following radial artery use in CABG remains a clinical question.

Purpose of the Study:

• To evaluate the evidence for the necessity of CCBs or nitrates when using a radial artery conduit for CABG.
• To assess the impact of these vasodilators on preventing vasospasm and improving graft patency.

Main Methods:

• A best evidence topic search was conducted, identifying 14 relevant papers from 98 initial findings.
• Data on author, journal, publication date, country, patient group, outcomes, and study weaknesses were tabulated.
• Analysis focused on clinical studies addressing CCB and nitrate use with radial artery grafts.

Main Results:

• No clinical studies provided evidence for the benefit of routine CCBs or nitrates in reducing vasospasm.
• One study indicated increased radial artery blood flow with vasoconstrictor-induced hypertension.
• Another study found CCBs did not attenuate serotonin-induced vasospasm in vivo.

Conclusions:

• Current evidence does not support the routine use of CCBs and nitrates to prevent vasospasm in radial artery grafts.
• The identified studies are underpowered to definitively exclude a benefit of vasodilators on medium-term graft patency.
• Large-scale randomized controlled trials would be required to detect small improvements in graft patency rates.