Anatomical Variations in the Sinoatrial Nodal Artery: A Meta-Analysis and Clinical Considerations

Abstract

Background and ObjectiveThe sinoatrial nodal artery (SANa) is a highly variable vessel which supplies blood to the sinoatrial node (SAN). Due to its variability and susceptibility to iatrogenic injury, our study aimed to assess the anatomy of the SANa and determine the prevalence of its anatomical variations.Study DesignAn extensive search of major electronic databases was performed to identify all articles reporting anatomical data on the SANa. No lower date limit or language restrictions were applied. Anatomical data regarding the artery were extracted and pooled into a meta-analysis.ResultsSixty-six studies (n = 21455 hearts) were included in the meta-analysis. The SANa usually arose as a single vessel with a pooled prevalence of 95.5% (95%CI:93.6–96.9). Duplication and triplication of the artery were also observed with pooled prevalence of 4.3% (95%CI:2.8–6.0) and 0.3% (95%CI:0–0.7), respectively. The most common origin of the SANa was from the right coronary artery (RCA), found in 68.0% (95%CI:55.6–68.9) of cases, followed by origin from the left circumflex artery, and origin from the left coronary artery with pooled prevalence of 22.1% (95%CI:15.0–26.2) and 2.7 (95%CI:0.7–5.2), respectively. A retrocaval course of the SANa was the most common course of the artery with a pooled prevalence of 47.1% (95%CI:36.0–55.5). The pooled prevalence of an S-shaped SANa was 7.6% (95%CI:2.9–14.1).ConclusionsThe SANa is most commonly reported as a single vessel, originating from the RCA, and taking a retrocaval course to reach the SAN. Knowledge of high risk anatomical variants of the SANa, such as an S-shaped artery, must be taken into account by surgeons to prevent iatrogenic injuries. Specifically, interventional or cardiosurgical procedures, such as the Cox maze procedure for atrial fibrillation, open heart surgeries through the right atrium or intraoperative cross-clamping or dissection procedures during mitral valve surgery using the septal approach can all potentiate the risk for injury in the setting of high-risk morphological variants of the SANa.

A novel method with which to visualize the human sinuatrial node: Application for a better understanding of the gross anatomy of this part of the conduction system

“…As James () suggested the following SANb to the SAN for the latter identification, this arterial branch has been investigated in a number of anatomical and histological studies (Vikse et al, ; Tohno et al, ). Vikse and his colleagues conducted a meta‐analysis on the SANb and found that it demonstrates a retrocaval course most commonly (47.1%), and its origin is from the right coronary, left circumflex, or left coronary arteries.…”

The Maze Procedure and Postoperative Pacemakers

“…The SA node artery originates from the right coronary artery in 63% of patients and from the left coronary artery in 37%, and its origin is unrelated to coronary artery dominance [28]. A recent meta-analysis of the reports on a total of 21,455 hearts showed that regardless of its origin, the SA node artery passes posterior to the orifice of the SVC in 100% of patients [32]. Two percent of patients have a second SA node artery that passes anterior to the orifice of the SVC.…”

Development of the Anatomical Quality Assessment (AQUA) Tool for the quality assessment of anatomical studies included in meta‐analyses and systematic reviews

“…Items for the AQUA Tool were generated on the basis of (1) the extensive background of the steering committee in conceiving and executing anatomical metaanalyses and systematic reviews, and (2) a review of the anatomical literature (Andall et al, 2015;Henry et al, 2015aHenry et al, , 2015bRamakrishnan et al, 2015;Roy et al, 2015;Tomaszewski et al, 2016aTomaszewski et al, , 2016bTomaszewski et al, , 2016cTomaszewski et al, , 2016dVikse et al, 2016). No comprehensive systematic review of systematic reviews was performed because there was no previously-used quality assessment of anatomical studies, and the number of true evidence-based reviews and meta-analyses in the literature is limited.…”