title: Anatomical Variations in the Sinoatrial Nodal Artery: A Meta-Analysis and Clinical Considerations.
abstract: OBJECTIVE
  The 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.
  
  
  METHODS
  An 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.
  
  
  RESULTS
  Sixty-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).
  
  
  CONCLUSIONS
  The 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.
authors: International Evidence-Based Anatomy Working Group, Krakow, Poland.|Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors: Jens
authors: J
authors: Vikse
authors: International Evidence-Based Anatomy Working Group, Krakow, Poland.|Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors: Brandon Michael
authors: BM
authors: Henry
authors: International Evidence-Based Anatomy Working Group, Krakow, Poland.|Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors: Joyeeta
authors: J
authors: Roy
authors: International Evidence-Based Anatomy Working Group, Krakow, Poland.|Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors: Piravin Kumar
authors: PK
authors: Ramakrishnan
authors: First Faculty of Medicine, Charles University, Prague, Czech Republic.
authors: Wan Chin
authors: WC
authors: Hsieh
authors: International Evidence-Based Anatomy Working Group, Krakow, Poland.|Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors: Jerzy A
authors: JA
authors: Walocha
authors: International Evidence-Based Anatomy Working Group, Krakow, Poland.|Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
authors: Krzysztof A
authors: KA
authors: Tomaszewski
mesh_terms: D006348:Cardiac Surgical Procedures; D003331:Coronary Vessels / Q000033:anatomy & histology*; D006801:Humans; D012849:Sinoatrial Node / Q000033:anatomy & histology* / Q000601:surgery