Phasic flow patterns of right versus left coronary arteries in patients undergoing clinical physiological assessment

Henry Seligman, Sukhjinder S. Nijjer, Tim P. van de Hoef, Guus A. de Waard, Hernán Mejía-Rentería, Mauro Echavarria-Pinto, Matthew J. Shun-Shin, James P. Howard, Christopher M. Cook, Takayuki Warisawa, Yousif Ahmad, Vitaliy Androshchuk, Christopher Rajkumar, Alexandra Nowbar, Mihir A. Kelshiker, Martijn A. van Lavieren, Martijn Meuwissen, Ibrahim Danad, Paul Knaapen, Sayan SenRasha Al-Lamee, Jamil Mayet, Javier Escaned, Jan J. Piek, Niels van Royen, Justin E. Davies, Darrel P. Francis, Ricardo Petraco

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)


BACKGROUND: Coronary blood flow in humans is known to be predominantly diastolic. Small studies in animals and humans suggest that this is less pronounced or even reversed in the right coronary artery (RCA). AIMS: This study aimed to characterise the phasic patterns of coronary flow in the left versus right coronary arteries of patients undergoing invasive physiological assessment. METHODS: We analysed data from the Iberian-Dutch-English Collaborators (IDEAL) study. A total of 482 simultaneous pressure and flow measurements from 301 patients were included in our analysis. RESULTS: On average, coronary flow was higher in diastole both at rest and during hyperaemia in both the RCA and LCA (mean diastolic-to-systolic velocity ratio [DSVR] was, respectively, 1.85±0.70, 1.76±0.58, 1.53±0.34 and 1.58±0.43 for LCArest, LCAhyp, RCArest and RCAhyp, p<0.001 for between-vessel comparisons). Although the type of RCA dominance affected the DSVR magnitude (RCAdom=1.55±0.35, RCAco-dom=1.40±0.27, RCAnon-dom=1.35; standard deviation not reported as n=3), systolic flow was very rarely predominant (DSVR was greater than or equal to 1.00 in 472/482 cases [97.9%] overall), with equal prevalence in the LCA. Stenosis severity or microvascular dysfunction had a negligible impact on DSVR in both the RCA and LCA (DSVR x hyperaemic stenosis resistance R2 =0.018, p=0.03 and DSVR x coronary flow reserve R2 <0.001, p=0.98). CONCLUSIONS: In patients with coronary artery disease undergoing physiological assessment, diastolic flow predominance is seen in both left and right coronary arteries. Clinical interpretation of coronary physiological data should therefore not differ between the left and the right coronary systems.

Original languageEnglish
Pages (from-to)1260-1270
Number of pages11
Issue number15
Early online date3 Aug 2021
Publication statusPublished - 18 Feb 2022


  • Blood Flow Velocity/physiology
  • Constriction, Pathologic
  • Coronary Circulation/physiology
  • Coronary Vessels/diagnostic imaging
  • Diastole
  • Humans
  • Hyperemia
  • fractional flow reserve
  • other technique
  • stable angina

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