Original Article
Prognostic value of early left ventricular ejection fraction reserve during regadenoson stress solid-state SPECT-MPI

https://doi.org/10.1007/s12350-020-02420-wGet rights and content

Abstract

Background

We hypothesized early post-stress left ventricular ejection fraction reserve (EFR) on solid-state-SPECT is associated with major cardiac adverse events (MACE).

Methods

151 patients (70 ± 12 years, male 50%) undergoing same-day rest/regadenoson stress 99mTc-sestamibi solid-state SPECT were followed for MACE. Rest imaging was performed in the upright and supine positions. Early stress imaging was started 2 minutes after the regadenoson injection in the supine position and followed by late stress acquisition in the upright position. Total perfusion deficit (TPD) and functional parameters were quantified automatically. EFR, ∆end-diastolic volume (EDV), and end-systolic volume (ESV) were calculated as the difference between stress and rest values in the same position. EFR < 0%, ∆EDV ≥ 5 ml, or ∆ESV ≥ 5 ml was defined as abnormal.

Results

During the follow-up (mean 3.2 years), 28 MACE occurred (19%). In Kaplan–Meier analysis, there was a significantly decreased event-free survival in patients with early EFR < 0% (P = 0.004). Similarly, there was a decreased event-free survival in patients with ∆ESV ≥ 5 ml at early stress (P = 0.003). However, EFR, ∆EDV, and ∆ESV at late stress were not associated with MACE-free survival. Cox proportional hazards model adjusting for clinical information and stress TPD demonstrated that EFR, ∆EDV, and ∆ESV at early stress were significantly associated with MACE (P < 0.05 for all).

Conclusions

Reduced early post-stress EFR on vasodilator stress solid-state SPECT is associated with MACE.

Introduction

Although evidence supporting the use of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for risk assessment and clinical decision making has accumulated over the last 30 years,1 regional perfusion alone may underestimate the extent of coronary artery disease (CAD).2,3 In particular, relative perfusion defects may not identify patients with left main or multi-vessel disease due to balanced ischemia.2,3 However, such high-risk patients are the most important to identify since they have poor cardiac outcomes and may benefit from revascularization.4, 5, 6 Traditionally, high-risk nonperfusion parameters such as transient ischemic dilation 7,8 and post-ischemic stunning 9 have been used as aids to identify patients with more severe CAD than would be predicted by relative perfusion alone on SPECT or positron emission computed tomography (PET) MPI.

One advantage of PET is the ability to rapidly measure LV function during peak hyperemia, which is not possible with conventional SPECT camera systems. Previous PET studies demonstrated that early post-stress EF reserve is a useful diagnostic and prognostic marker.10, 11, 12

The recent emergence of solid-state SPECT camera systems resulted in significant improvements in count sensitivity 13 and diagnostic accuracy for CAD 14, 15, 16, 17 allowing shorter acquisition times to facilitate early post-stress imaging. Previously, our group evaluated a novel imaging protocol with early gated acquisitions after regadenoson stress using a solid-state SPECT camera system and demonstrated that patients with significant ischemia were more likely to have negative early post-stress EF reserve.17 In the current study, we sought to establish if early post-stress EF reserve or change in end-systolic volume (ESV) and end-diastolic volume (EDV), measured using solid-state SPECT MPI, is associated with major adverse cardiac events (MACE).

Section snippets

Study Population

Patients referred for clinically indicated rest/regadenoson stress SPECT MPI at the Nuclear Medicine Department, Sacred Heart Medical Center, Springfield, Oregon, between November 2013 and May 2016, were considered for the protocol. Final patient selection depended on the ability to accommodate additional imaging during this protocol and, in particular, the ability to have stress lab and nursing staff available during the entire procedure. Out of 1224 patients who underwent rest/regadenoson

Outcome Events

During the mean follow-up of 3.2 ± 1.1 years, 28 MACE (19%) occurred including 13 deaths, 9 myocardial infarctions, and 6 coronary revascularizations.

Clinical Characteristics and Hemodynamic Results

Clinical characteristics and hemodynamic results are shown in Table 1. Patients with MACE were older (mean age 77 vs 68, P = 0.0005) and more likely to have a history of prior PCI (43% vs 17%, P = 0.003). There was no significant difference in hemodynamic results between patients with and without MACE.

Stress and Rest Quantitative MPI Results

SPECT imaging results are shown in Table 2.

Discussion

This is the first study to evaluate the utility of early post-stress imaging for MACE on vasodilator stress solid-state SPECT MPI. Abnormal early post-stress EF reserve and change in ESV were more commonly observed in patients who experienced MACE and stratified MACE-free survival, while late post-stress imaging did not. Multivariable analysis demonstrated that early post-stress functional parameters were independently associated with MACE after adjusting for clinical and perfusion variables.

Conclusion

Ejection fraction reserve, ∆ EDV, and ESV measured after early post-stress by solid-state SPECT MPI provide significant, independent, and incremental value for predicting the risk of adverse cardiovascular events. The measurement of LVEF reserve is possible using a solid-state SPECT system and prospective validation of the potential value of this information is warranted.

New Knowledge Gained

Early ejection fraction reserve, measured using solid-state SPECT MPI, was significantly decreased in patients who experienced MACE. Early post-stress (but not late) ejection fraction reserve was independently associated with MACE and improved risk stratification compared to a model with other important SPECT MPI variables.

Disclosure

Dr. Slomka participates in software royalties for QPS software at Cedars-Sinai Medical Center and has received research grant support from Siemens Medical Systems. All other authors have nothing to disclose.

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  • Cited by (4)

    Yuka Otaki and Mathews B. Fish have contributed equally to this work.

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