The effect of vasodilatory medications on radial artery spasm in patients undergoing transradial coronary artery procedures: a systematic review
Authors: Curtis Elizabeth , Fernandez Ritin , Lee Astin 
Published: July 2017

EXECUTIVE SUMMARY

Background
The uptake of percutaneous coronary procedures via the radial artery has increased internationally due to the decreased risk of complications and increased patient satisfaction. The increased susceptibility of the radial artery to spasm however presents a potential risk for procedural failure. Although most experts agree on the need for prophylactic medications to reduce radial artery spasm, currently there is inconsistency in literature regarding the most effective vasodilatory medication or combination of medications.

Review objective
The objective of this study is to identify the effectiveness of vasodilatory medications on radial artery spasm in patients undergoing transradial coronary artery procedures.

Inclusion criteria Types of participants
This review considered studies that included participants aged 18 years and over undergoing non-emergent transradial percutaneous coronary artery procedures.

Types of intervention(s)
This review considered studies that used vasodilating intravenous and intra-arterial medications or combinations of medications prior to commencing and during transradial coronary approaches to reduce radial artery spasm.

Outcomes
The outcomes of interest were the incidence of radial artery spasm during percutaneous coronary procedure using objective and/or subjective measures and its effect on the successful completion of the procedure.

Types of studies
Randomized controlled trials published in the English language between 1989 to date were considered for inclusion.

Search strategy
The search strategy aimed to find both published and unpublished studies. A three-step search strategy was utilized in this review. An initial search of MEDLINE, CINAHL and Scopus was undertaken, followed by a search for unpublished studies.

Assessment of methodological quality
Papers selected for retrieval were assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments. Any disagreements that arose between the reviewers were resolved through discussion.

Data extraction
Quantitative data was extracted from papers included in the review using the standardized data extraction tool from RevMan5 (Copenhagen: The Nordic Cochrane Centre, Cochrane).

Data synthesis
Quantitative data, where possible, was pooled in statistical meta-analysis using RevMan5. All results were subject to double data entry. Effect sizes expressed as risk ratio (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals were calculated for analysis.

Results
Nine trials involving 3614 patients were included in the final review. Pooled data involving 992 patients on the effect of calcium channel blockers demonstrated a statistically significant reduction in the incidence of vasospasm in patients who received verapamil 5 mg compared to those who received a placebo (OR 0.33; 95%CI 0.19, 0.58). Similarly patients who received verapamil 2.5 mg or 1.25 mg had significantly fewer incidences of vasospasm when compared to those who received a placebo. Nitroglycerine 100mcg was demonstrated to be associated with a statistically significant reduction in the incidence of vasospasm.

Conclusion
The evidence demonstrates a benefit in the use of vasodilatory medications for the reduction of vasospasm in patients having radial coronary procedures. Further large-scale multi-center trials are needed to determine the preferred medication.