The largest prospective study conducted to assess the prevalence and prognosis of coronary dominance of patients undergoing a coronary CT angiography (CCTA) examination has revealed that identifying coronary dominance may not enhance risk stratification in patients with normal coronary arteries or obstructive coronary artery disease (CAD). However, the identification of left dominance may offer different prognostic values regarding short- and long-term mortality in patients with acute coronary syndromes (ACS), according to findings published in the August issue of European Heart Journal.
The Coronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter (CONFIRM) registry represents an ambitions multinational effort by 12 medical centers located in Canada, the United States, Germany, Italy, Switzerland and Korea. The registry, which includes more than 20,000 patients with suspected CAD who underwent a 64-detector row or greater CCTA exam, is the first prospective database evaluating the prognostic role of CCTA.
The study was undertaken because very little information exists about the prognostic value of coronary vessel dominance in patients referred for CCTA, according to lead author Catherine Gebhard, M.D. of the department of nuclear medicine at University Hospital Zurich and co-authors. They were interested in confirming or ruling out the hypothesis that a left dominant coronary system may reflect a biological disadvantage relative to right dominance. They noted that results of two large prior studies of approximately 27,000 and 208,000 individuals had demonstrated this, but that the research had been based on conventional angiograms.1,2
“Since it is often difficult to delineate the course of coronary arteries by angiography because it only provides a two-dimensional view of a three-dimensional structure, the present study analyzed coronary dominance and outcome by multidetector coronary CCTA that not only provides information about the presence and degree of coronary stenosis, but also allows to see the origin and course of coronary arteries by a three-dimensional display of anatomy, thereby permitting the determination of coronary artery variations,” the authors wrote.
The patient cohort evaluated included 6,382 individuals with or without CAD who had had their coronary artery dominance pattern evaluated between 2005 and 2009. Fifty-three percent of the group were male (47% female), with a median age of 56.9 years (and an age range of 44 to 68). They were followed up to five years. Right dominance was present in 91% of this group.
The primary clinical endpoint of the study was a composite of all-cause mortality, non-fatal myocardial infarction, and early and late coronary revascularizations. During the 60 month follow-up period, 5% of the patients experienced a clinical endpoint. One hundred patients died. One hundred twenty patients underwent revascularization, and 131 patients experienced non-fatal myocardial infarction. After evaluation of each endpoint, no significant differences were observed in patients with normal coronary arteries or with patients with significant CAD regardless of whether they were right- or left-dominant.
The researchers did report a higher incidence of both obstructive and non-obstructive CAD in left dominance patients. The prevalence of normal coronary arteries was more frequent in right dominance patients.
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The CONFIRM study results: Assessment of coronary dominance by CCTA. Appl Radiol.