Hemodynamic Changes in Children Associated with Dobutamine Stress CMR for Anomalous Aortic Origin of the Coronary Arteries (RF_SA_467)

Presenting Author(s)

• KC

  Karen Carvalho, MD

  Pediatric Cardiology Fellow
  Ann & Robert H Lurie Children's Hospital

Primary Author(s)

• KC

  Karen Carvalho, MD

  Pediatric Cardiology Fellow
  Ann & Robert H Lurie Children's Hospital

Co-Author(s)

• 

  Simon Lee, MD

  Associate Professor of Pediatrics
  Ann & Robert H. Lurie Children's Hospital of Chicago
• 

  Nazia Husain, MD, MPH

  Attending Physician
  Ann & Robert H. Lurie Children's Hospital of Chicago
• 

  Joshua D. Robinson, MD, FSCMR

  Section Head, Cardiac Imaging
  Lurie Children's Hospital of Chicago
  Lurie Children's Hospital
• 

  Cynthia K. Rigsby, MD

  Chair
  Ann & Robert H. Lurie Children's Hospital of Chicago
• KO

  Kristy O'Connor, RN, BN

  Procedural Nurse Coordinator
  Ann & Robert H Lurie Children's Hospital
• AE

  Amanda Eichstaedt, RN

  Manager Patient Care Operations
  Ann & Robert H. Lurie Children’s Hospital of Chicago
• Ad

  Andrew de Freitas, MD

  Associate Professor
  Ann & Robert H Lurie Children's Hospital
• EV

  Eric Vu, MD

  Associate Professor
  UT Health Houston McGovern Medical School
• SS

  Scott Stenquist, MD

  Assistant Professor
  Ann & Robert H Lurie Children's Hospital

Background: Anomalous aortic origin of a coronary artery (AAOCA) is associated with sudden cardiac death. Traditionally, 85% peak heart rate (HR) for age has been used as a goal for achieving peak stress during dobutamine stress CMR (DSCMR). This may result in challenges in pediatric imaging where target heart rates are high. Rate pressure product (RPP), the product of heart rate and systolic blood pressure, has been shown to be a proxy for myocardial oxygen consumption and to correlate with onset of coronary hypoperfusion during exercise.^1,2 There may be a role to utilize a target RPP of >20,000 bpm*mmHg to identify hypoperfusion in pediatric patients with AAOCA.^3,4 Myocardial perfusion reserve index (MPRI) offers a semiquantitative assessment of coronary blood flow and has shown differences in those with and without coronary ischemia with DSCMR.^5,6 The correlation of CMR-derived cardiac output (CO) and MPRI with RPP-identified peak stress has not been established. We aim to describe hemodynamic changes during DSCMR in patients with AAOCA achieving a RPP >20,000 bpm*mmHg.

Methods: Seven consecutive patients (median 15 years, range 8-19) with AAOCA who underwent DSCMR were included, two of which were under anesthesia. Imaging protocol is shown in Figure 1. Vital sign data was collected at baseline, q2min during dobutamine titration, and q2min for 20 min after completion. Dobutamine was titrated by 10 mcg/kg/min q4 min with the goal of 40 mcg/kg/min. Atropine was given as needed to augment HR. Contrast was administered at peak stress once RPP was >20,000 bpm*mmHg and patient received at least 2 min of their current dose of dobutamine. Rest and stress 2D phase contrast imaging of the ascending aorta was used to calculate CO. Feature tracking global circumferential strain (GCS) and MPRI calculation were analyzed using Medis Suite 4.0.

Results: Five had an anomalous right coronary artery from the left sinus (ARCA), and 2 had an anomalous left coronary artery from the right sinus (ALCA). All but one patient received 40 mcg/kg/min of dobutamine and atropine. There were no complications. One ALCA patient had a reversible perfusion defect in the basal and mid antero- and inferoseptal segments. Global MPRI in non-ischemic segments was 2.6 (IQR 2.2-3.5).  Median hemodynamic changes with rest and stress are shown in Table 1. The median peak RPP achieved for all was 23,355 bpm*mmHg (IQR 23,086 to 25,036) (Figure 2). The median CO at rest was 4.8L/min, increasing to 9.5L/min (Δ+97%) with stress. Indexed to body surface area, cardiac index at rest was 3.2L/min/m2, increasing to 6.6L/min/m2 (Δ+108%) with stress. A median %peak HR of 72% (IQR 68%-72%) was achieved.  GCS increased from 31.5% (IQR 24.7-35.5) at rest to 44.4% (IQR 40.4-51.3) at peak stress.

Conclusion: Using an RPP goal of >20,000 bpm*mmHg to establish peak stress during DSCMR results in doubling of CO, augmentation of GCS, and an MPRI similar to non-ischemic hearts. This initial data supports the idea that using a goal RPP may be an adequate measure of peak stress.

Dobutamine stress CMR institutional protocol

Hemodynamic changes over the different stages of dobutamine. A) Median heart rate and systolic blood pressure over progressive dobutamine doses; B) Rate pressure product for all seven patients over progressive dobutamine doses.