Viability Test in Prediction of Response to Cardiac Resynchronization Therapy
Isidora Grozdic Milojevic1,2, Nikola N Radovanovic2,3, Jelena Petrovic1,2
1Center for Nuclear Medicine and PET, University Clinical Center of Serbia, 11000 Belgrade, Serbia.
Insights
Nuclear imaging parameters, specifically myocardial scar size, effectively predict cardiac resynchronization therapy (CRT) response and survival in ischemic heart failure patients. A scar burden under 19.5% indicates suitability for CRT and better outcomes.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Ischemic heart failure (HF) patients often require cardiac resynchronization therapy (CRT).
- Predicting CRT response and long-term outcomes in these patients remains challenging.
- Myocardial scar burden and distribution may influence CRT efficacy.
Purpose of the Study:
- To evaluate myocardial scar burden and distribution using SPECT MPI.
- To assess the predictive value of SPECT MPI parameters for CRT response.
- To determine the relationship between scar characteristics and long-term survival in ischemic HF patients undergoing CRT.
Main Methods:
- Prospective inclusion of 71 ischemic HF patients indicated for CRT.
- Pre-CRT SPECT MPI for myocardial scar assessment.
- Echocardiography before and 6 months after CRT implantation.
- 5-year telephone follow-up for survival assessment.
Main Results:
- SPECT MPI showed significant myocardial scar burden (44.53 ± 20.94%) and high summed rest scores (SRS).
- 35% of patients were CRT responders at 6 months.
- Lower SRS and smaller myocardial scar size (<19.5%) were significant predictors of CRT response (AUC 0.853).
Conclusions:
- SPECT MPI parameters, particularly myocardial scar size, are valuable predictors of CRT response.
- A myocardial scar size <19.5% is associated with better CRT response and improved cardiovascular survival.
- SPECT MPI can aid in patient selection for CRT in ischemic HF.
Abstract:
Background/Objectives: This study aimed to evaluate myocardial scar burden and distribution, as well as other nuclear imaging parameters, in predicting cardiac resynchronization therapy (CRT) responses and long-term outcomes in patients selected for CRT with ischemic HF etiology. Methods: Seventy-one patients were prospectively included. They all had NYHA class II/III despite optimal medical therapy, LVEF ≤ 35%, wide QRS complexes, and ischemic HF etiology. All were indicated for de novo CRT implantation and underwent a SPECT MPI viability test prior to CRT implantation. Two-dimensional echocardiography was performed one day before CRT implantation and 6 months after the intervention. The follow-up examination was conducted six months after the CRT implantation and, after 5 years, patients underwent a telephone follow-up to assess survival. Results: Most patients (85%) were male, with an average age of 66.26 ± 9.25 yrs. SPECT MPI revealed large myocardial scars (44.53 ± 20.94%) with high summed rest scores (SRSs) of 25.02 ± 11.29 and low EFs of 26.67 ± 7.71%. At the 6-month follow-up, after the CRT implantation, the NYHA class significantly changed and 35% of the patients were classified as CRT responders. The only difference between responders and non-responders was in the SRS and myocardial scar size (p < 0.001). A scar size of 19.5% was an optimal cutoff for the prediction of CRT response (AUC 0.853, Sn 85% and 1-sp 94%). Conclusions: SPECT MPI parameters are valuable in predicting responses and long-term survival in patients with CRT. Patients with myocardial scars of less than 19.5% may be suited to CRT and experience better cardiovascular survival.
