# Comparative Efficacy and Safety of Vasodilators Used to Prevent Internal Thoracic Artery Spasm in Coronary Artery Bypass Grafting: A Systematic Review

## TL;DR

This review compares vasodilators used to prevent artery spasm during heart surgery, finding that a combination solution works best.

## Contribution

The study provides a systematic comparison of vasodilators for preventing ITA spasm during CABG, highlighting the efficacy of GV solution.

## Key findings

- GV solution showed superior efficacy with rapid onset and high potency in preventing ITA spasm.
- Papaverine was effective but had a slower onset compared to other vasodilators.
- Combination therapy (GV solution) is a practical and safe approach for intraoperative ITA spasm prevention.

## Abstract

Internal thoracic artery (ITA) spasm during coronary artery bypass grafting (CABG) can compromise graft flow and perioperative outcomes. This review systematically evaluates the comparative efficacy and safety of vasodilators used to prevent ITA spasm, including papaverine, glyceryl trinitrate-verapamil (GV) solution, systemic diltiazem, and efonidipine. Six studies comprising clinical, ex vivo, and in vitro investigations were included. GV solution consistently demonstrated superior vasodilatory efficacy, rapid onset (2.9 min), and high potency, achieving near-complete ITA relaxation and increasing intraoperative free flow by up to 95%, with minimal adverse events. Papaverine effectively prevented spasm at high concentrations but showed a slower onset. Systemic diltiazem improved graft flow safely, while efonidipine exhibited dose-dependent relaxation in ex vivo models, targeting both L- and T-type calcium channels. Delivery method influenced efficacy, with topical or intraluminal administration providing rapid, direct vasodilation. Overall, combination therapy (GV solution) offers a practical and safe approach for intraoperative ITA spasm prevention.