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High-Resolution Cardiac Positron Emission Tomography/Computed Tomography for Small Animals
Published on: December 16, 2022
The relation between cardiac 123I-mIBG scintigraphy and functional response 1 year after CRT implantation
D O Verschure1,2, E Poel1, G De Vincentis3
1Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Location Amsterdam Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
Insights
Cardiac sympathetic activity assessed by 123I-mIBG scintigraphy can predict response to cardiac resynchronization therapy (CRT). This imaging technique may help optimize patient selection for CRT in chronic heart failure (CHF).
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Cardiac resynchronization therapy (CRT) is a key treatment for chronic heart failure (CHF).
- Current CRT eligibility relies on left ventricular ejection fraction (LVEF), QRS duration, and NYHA functional class.
- A significant portion of CHF patients do not respond to CRT, necessitating improved patient selection criteria.
Purpose of the Study:
- To investigate the utility of 123I-meta-iodobenzylguanidine (123I-mIBG) scintigraphy in predicting CRT response.
- To determine if cardiac sympathetic activity, assessed by 123I-mIBG, can optimize patient selection for CRT.
Main Methods:
- Seventy-eight stable CHF patients undergoing CRT implantation were enrolled.
- 123I-mIBG scintigraphy was performed, calculating early and late heart-to-mediastinum (H/M) ratios and 123I-mIBG washout.
- CRT response was defined by improvements in LVEF, QRS duration, or NYHA class.
Main Results:
- Late H/M ratio and hypertension independently predicted LVEF improvement to >35%.
- Early H/M ratio, LVEF, and absence of diabetes mellitus predicted LVEF improvement by >10%.
- No independent predictors were identified for QRS shortening or NYHA class improvement.
Conclusions:
- Early and late H/M ratios are independent predictors of CRT response when LVEF improvement is the response measure.
- 123I-mIBG scintigraphy shows potential as a tool to enhance the selection of CRT candidates.
Aims:
Cardiac resynchronization therapy (CRT) is a disease-modifying therapy in patients with chronic heart failure (CHF). Current guidelines ascribe CRT eligibility on three parameters only: left ventricular ejection fraction (LVEF), QRS duration, and New York Heart Association (NYHA) functional class. However, one-third of CHF patients does not benefit from CRT. This study evaluated whether 123I-meta-iodobenzylguanidine (123I-mIBG) assessed cardiac sympathetic activity could optimize CRT patient selection.
Methods And Results:
A total of 78 stable CHF subjects (age 66.8 ± 9.6 years, 73% male, LVEF 25.2 ± 6.7%, QRS duration 153 ± 23 ms, NYHA 2.2 ± 0.7) referred for CRT implantation were enrolled. Subjects underwent 123I-mIBG scintigraphy prior to implantation. Early and late heart-to-mediastinum (H/M) ratio and 123I-mIBG washout were calculated. CRT response was defined as either an increase of LVEF to >35%, any improvement in LVEF of >10%, QRS shortening to <150 ms, or improvement in NYHA class of >1 class. In 33 patients LVEF increased to >35%, QRS decreased <150 ms in 36 patients, and NYHA class decreased in 33 patients. Late H/M ratio and hypertension were independent predictors of LVEF improvement to >35% (P = 0.0014 and P = 0.0149, respectively). In addition, early H/M ratio, LVEF, and absence of diabetes mellitus (DM) were independent predictors for LVEF improvement by >10%. No independent predictors were found for QRS shortening to <150 ms or improvement in NYHA class.
Conclusion:
Early and late H/M ratio were independent predictors of CRT response when improvement of LVEF was used as measure of response. Therefore, cardiac 123I-mIBG scintigraphy may be used as a tool to optimize selection of subjects that might benefit from CRT.
