title: Utility of coronary CT angiography in outpatients with hypertrophic cardiomyopathy presenting with angina symptoms.
abstract: BACKGROUND
  Angina is a frequent symptom in patients with hypertrophic cardiomyopathy (HCM); however, it is often not because of significant epicardial coronary artery stenosis. Coronary CT angiography (CCTA) is an excellent modality to rule out significant coronary artery stenosis in the low- and intermediate-risk patients; however, its value in patients with HCM has not been explored. We sought to assess the utility of CCTA in the assessment of patients with HCM and stable anginal symptoms and compare the incidence of epicardial coronary artery stenosis to an age- and gender-matched control group.
  
  
  METHODS
  Consecutive outpatients with HCM referred for CCTA over a 3-year period because of stable anginal symptoms (chest pain or shortness of breath) were identified retrospectively. Age- and gender-matched patients without HCM referred for CCTA because of similar symptoms over a 6-month period were used as controls. All patients had CCTA using an Aquilion ONE 320 scanner. The coronary arteries were evaluated independently by 2 blinded observers, and any luminal narrowing was scored quantitatively as follows: >70% = severe; 50% to 70% = moderate; <50% = mild; and none. For the HCM group, results of cardiac single-photon emission CT (SPECT) or cardiac magnetic resonance perfusion studies as well as catheter angiograms were recorded where available.
  
  
  RESULTS
  A total of 91 patients with HCM and 91 controls were included. No significant difference in cardiac risk factors was present between the 2 groups. The CCTA was of diagnostic quality in all patients. The median (interquartile range) calcium score was lower in patients with HCM (0 [0-50] vs 2 [0-189]) but did not reach statistical significance (P = .23). The incidence of moderate-to-severe coronary artery stenosis was significantly lower in patients with HCM than in controls (6.6% vs 33.0%; P < .001). The incidence of left anterior descending artery luminal narrowing overall was also significantly lower in the HCM patients (7.0% vs 20.9%; P = .002). There was a higher incidence of myocardial bridging in patients with HCM (40.7% vs 6.6%; P < .001), with longer and deeper bridged segments. Among a subgroup of HCM patients (n = 24) who had either stress perfusion CMR or cardiac single-photon emission CT studies performed, 15 of 24 had false-positive perfusion abnormalities without evidence of luminal obstruction on CCTA.
  
  
  CONCLUSIONS
  We demonstrate the use of CCTA for the assessment of stable anginal symptoms in patients with HCM. The incidence of moderate-to-severe coronary artery stenosis was significantly lower in our HCM patients in comparison to our age-matched, gender-matched, and risk factor-matched control group. Given the high incidence of false-positive findings on perfusion stress studies, we propose that CCTA may be useful for appropriate triage to coronary angiography in the HCM patient with anginal symptoms.
authors.affiliation: Department of Medical Imaging, Toronto General Hospital, 585 University Avenue, Toronto M5G 2C4, Canada. Electronic address: masoudshariat@gmail.com.
authors.forename: Masoud
authors.initials: M
authors.lastname: Shariat
authors.affiliation: Division of Cardiology, Department of Medicine, Peter Munk Cardiac Center, Toronto General Hospital, Toronto M5G 2C4, Canada.
authors.forename: Paaladinesh
authors.initials: P
authors.lastname: Thavendiranathan
authors.affiliation: Department of Medical Imaging, Toronto General Hospital, 585 University Avenue, Toronto M5G 2C4, Canada.
authors.forename: Elsie
authors.initials: E
authors.lastname: Nguyen
authors.affiliation: Department of Medical Imaging, Toronto General Hospital, 585 University Avenue, Toronto M5G 2C4, Canada.
authors.forename: Bernd
authors.initials: B
authors.lastname: Wintersperger
authors.affiliation: Department of Medical Imaging, Toronto General Hospital, 585 University Avenue, Toronto M5G 2C4, Canada.
authors.forename: Narinder
authors.initials: N
authors.lastname: Paul
authors.affiliation: Division of Cardiology, Department of Medicine, Peter Munk Cardiac Center, Toronto General Hospital, Toronto M5G 2C4, Canada.
authors.forename: Harry
authors.initials: H
authors.lastname: Rakowski
authors.affiliation: Department of Medical Imaging, Toronto General Hospital, 585 University Avenue, Toronto M5G 2C4, Canada; Division of Cardiology, Department of Medicine, Peter Munk Cardiac Center, Toronto General Hospital, Toronto M5G 2C4, Canada.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Crean
mesh_terms: D000328:Adult; D000368:Aged; D000553:Ambulatory Care; D060050:Angina, Stable / Q000000981:diagnostic imaging* / Q000453:epidemiology; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000453:epidemiology; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005189:False Positive Reactions; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D054084:Myocardial Bridging / Q000000981:diagnostic imaging / Q000453:epidemiology; D055414:Myocardial Perfusion Imaging / Q000379:methods; D009864:Ontario / Q000453:epidemiology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D061205:Vascular Calcification / Q000000981:diagnostic imaging / Q000453:epidemiology
keywords: Angina; Chest pain; Computed tomography coronary angiography; Coronary artery stenosis; Hypertrophic cardiomyopathy