Masae Uehara MD, Presenter: Nothing to Disclose

Nobusada Funabashi MD, PhD, Abstract Co-Author: Nothing to Disclose

Hiroyuki Takaoka MD, PhD, Abstract Co-Author: Nothing to Disclose

Yoshio Kobayashi, Abstract Co-Author: Nothing to Disclose

To evaluate the prognosis of hypertrophic cardiomyopathy (HCM) patients after cardiac CT and compare the risk of major adverse cardiac events (MACE) between HCM patients with and without focal myocardial fibrosis (MF) on CT using a Kaplan-Meier and Cox proportional hazard model.  

A total of 60 consecutive patients with HCM by transthoracic echocardiogram, (41 male, mean age 63± 14 years, Maron type 2 (32), type 3 (15), and type 5 (13)), who had suspected coronary artery disease without old myocardial infarction and who underwent cardiac CT (Light speed 16) from 2002 to 2008 on which no significant luminal stenosis (>50%) was observed, were included. Enhanced ECG-gated MSCT was performed at 30 seconds and 6 minutes after contrast injection to detect MF as contrast defects in the early phase and abnormal enhancement in late phase (Figure 1). Patients were followed for a median of 41 ± 30 months after cardiac CT. MACE included cardiac death, heart failure, cardiogenic shock, sustained ventricular tachycardia or ventricular fibrillation, and implantable cardioverter defibrillator shock because of ventricular arrhythmia. The incidence of MACE was compared with a Kaplan-Meier analysis and the log rank statistic.  

MF on CT was detected in 34 subjects. Patients with MF had a higher risk of MACE (26.5%) than those without (3.8%; p=0.03) during the observation period. Significant differences between HCM subjects with and without MF were also seen at each time point and when the whole period of follow-up was compared with a Kaplan-Meier and log rank test (p=0.02; Figure 2). A Cox proportional hazards model was used to test the significance of MF on CT as a predictor of MACE considering the influence of age, male sex, left ventricular asynergy, hypertrophic obstructive cardiomyopachy, apical hypertrophy, and time duration from the onset of HCM. This analysis revealed that the presence of MF on CT was a predictor of MACE (Hazard ratio 16.6, p=0.03).

HCM patients without coronary luminal stenosis but with MF on cardiac CT had a higher risk of MACE than those without following a median of 41 months using a Kaplan-Meier analysis and Cox proportional hazard regression with a hazard ratio of 16.6.

When coronary artery diseases are suspected in HCM subjects and late phase acquisition is added in CT, detection of focal MF may be useful to predict the risk of MACE in HCM subjects.

Uehara, M, Funabashi, N, Takaoka, H, Kobayashi, Y, Higher Risk Prognosis for Major Cardiac Events in Hypertrophic Cardiomyopathy with Myocardial Fibrosis by CT Following a Median of 41 Months Using Kaplan-Meier and Cox Proportional Hazard Regression.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11020061.html