The significance of post-stress decrease in left ventricular ejection fraction in patients undergoing regadenoson stress gated SPECT myocardial perfusion imaging

The Impact of Left Ventricle Ejection Fraction Reduction and Transient Ischemic Dilation in Patients With Normal Single-Photon Emission Computed Tomography (SPECT) Myocardial Perfusion Imaging

INTRODUCTION

Coronary artery disease (CAD) is a leading cause of death in developed countries. Non-invasive functional imaging modalities are currently recommended as initial diagnostic tests in patients with an intermediate-high pretest probability of CAD. Single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) creates images of regional myocardial tracer uptake, reflecting relative myocardial blood flow. However, there are other non-perfusion predictors of CAD, such as transient ischemic dilatation (TID) and reduced post-stress left ventricle ejection fraction (LVEF). Available data regarding these parameters is controversial. The aim of our study was to evaluate the incidence of significant CAD in patients with non-perfusion high-risk markers of ischemia despite a normal SPECT-MPI.

METHODS

Single-center, observational, retrospective, and longitudinal study. Inclusion criteria were age ≥18 years, normal SPECT-MPI, and availability of gated study for LVEF and volume analysis. Exclusion criteria were any known cardiomyopathy or congenital heart disease and known CAD. Non-perfusion high-risk markers: LVEF reduction ≥5% on post-stress images; TID (defined as a stress/rest left ventricle volume ratio ≥ 1.15), including end-systolic, end-diastolic, and mean volumes. The primary endpoint was the identification of significant CAD (stenosis >70% on an epicardial coronary artery or >50% on the left main artery) on invasive coronary angiography.

RESULTS

A total of 197 patients met the inclusion criteria. Mean age was 64 ± 12.6 years and 59.4% (n = 117) of patients were male. Overall, 26% of patients had LVEF reduction ≥5% on stress study; 24.9% had a stress/rest end-systolic volume ratio ≥ 1.15; 7.1% had a stress/rest mean volume ratio ≥ 1.15; 7.1% had a stress/rest end-diastolic volume ratio ≥ 1.15. Time-to-primary endpoint was significantly lower in patients with LVEF reduction ≥5% on stress study (67.99 (95% CI 60.49-75.49) vs. 77.56 months (95% CI 75.14-79.99); p = 0.003) and in patients with stress/rest end-systolic volume ratio ≥ 1.15 (68.39 (95% CI 60.69-76.10) vs. 77.31 months (95% ICCI 74.68-79.76); p = 0.013).

CONCLUSION

In patients with normal perfusion on SPECT-MPI, the incidence of significant CAD was significantly higher in those with LVEF reduction ≥ 5% on stress study and in those with a stress/rest end-systolic volume ratio ≥ 1.15, during a follow-up period of five years.

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

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.

Prognostic value of absent left ventricular ejection fraction reserve with regadenoson SPECT MPI

BACKGROUND

An absent left ventricular ejection fraction (LVEF) reserve with vasodilator stress with PET cardiac imaging has been shown to provide significant independent and incremental value to the perfusion images for prediction of future cardiovascular adverse events. However, the prognostic value of LVEF reserve has not been well characterized with SPECT myocardial perfusion imaging (MPI).

METHODS

We studied 858 consecutive patients with normal and abnormal perfusion pattern with regadenoson SPECT MPI. Change in LVEF was calculated as post-stress LVEF-rest LVEF. Absent LVEF reserve was defined as a drop in LVEF by 5% or more on the post-stress images. The primary outcome was a composite of cardiac death, non-fatal myocardial infarction and late coronary revascularization.

RESULTS

An absent LVEF reserve was more common in patients with abnormal vs normal MPI (31% vs 19%, P = .001). During a median follow-up of 32 months, the primary outcome was experienced by 31% of the study population. An absent LVEF reserve was not associated with an increased risk of the primary outcome in patients with normal (hazard ratio 1.1, 95% CI .4-2.7, P = .8) or abnormal (.75, .56-1.00, P = .05) MPI. There was no significant correlation between extent of ischemia and post-stress change in LVEF (Pearson r = - .072, P = .07).

CONCLUSIONS

In patients undergoing regadenoson SPECT MPI, absent LVEF reserve is not associated with worse cardiac outcomes. Thus, routine reporting of both post-stress and rest LVEF measurements in this setting may not be necessary.

The prognostic implications of ST-segment and T-wave abnormalities in patients undergoing regadenoson stress SPECT myocardial perfusion imaging

BACKGROUND

The prognostic implications of ST-segment and T-wave (ST/T) abnormalities in patients undergoing stress SPECT-myocardial perfusion imaging (MPI) are not well defined.

METHODS AND RESULTS

This was a single-center, retrospective cohort study of consecutive patients who underwent regadenoson stress SPECT-MPI. Patients with baseline electrocardiogram (ECG) abnormalities that impede ST/T analysis or those with known coronary artery disease were excluded. Patients were categorized as having primary ST abnormalities, secondary ST/T abnormalities due to ventricular hypertrophy or right bundle branch block, T-wave abnormalities, or normal ECG. The primary outcome was major adverse cardiovascular events (MACE) defined as the composite of cardiac death or myocardial infarction. Among 6,059 subjects, 1912 (32%) had baseline ST/T abnormalities. During a mean follow-up of 2.3 ± 1.9 years, the incidence of MACE was significantly higher among patients with secondary ST/T abnormalities compared to those with normal ECG (HR 2.05; 95% confidence interval [CI], 1.04-4.05; P = 0.039). No significant difference in MACE was observed among patients with primary ST abnormalities (HR 1.64; CI 0.87-3.06; P = 0.124) or T-wave abnormalities (HR 1.15; CI 0.62-2.16; P = 0.658) compared with patients who had normal ECG. Among patients with secondary ST/T changes, abnormal MPI was not associated with a significant increase in MACE rates compared to normal MPI (HR 1.18; CI 0.31-4.58; P = 0.808). However, abnormal MPI was associated with higher MACE rates among patients with primary ST abnormalities (HR 4.50; CI 1.44-14.10; P = 0.005) and T-wave abnormalities (HR 3.74; CI 1.20-11.68; P = 0.015). Similarly, myocardial ischemia on regadenoson stress SPECT-MPI was not associated with a significant increase in MACE rates in patients with secondary ST/T abnormalities (HR 1.45; CI 0.38-5.61; P = 0.588), while it was associated with a higher incidence of MACE in patients with primary ST abnormalities (HR 3.012; CI 0.95-9.53; P = 0.049) and T-wave abnormalities (HR 5.06; CI 1.60-15.96; P = 0.002).

CONCLUSION

While patients with secondary ST/T abnormalities had significantly higher MACE risk, abnormal MPI or presence of myocardial ischemia on regadenoson SPECT-MPI in this group does not add prognostic information. Patients with primary ST abnormalities and T-wave abnormalities do not seem to have a significantly higher MACE risk compared to those with normal ECG; however, abnormal MPI or presence of myocardial ischemia, in these groups, correlates with higher MACE rates.

The diagnostic and prognostic value of near-normal perfusion or borderline ischemia on stress myocardial perfusion imaging

BACKGROUND

Data on the diagnostic and prognostic value of subtle abnormalities on myocardial perfusion imaging (MPI) are limited.

METHODS AND RESULTS

In a retrospective single-center cohort of patients who underwent regadenoson SPECT-MPI, near-normal MPI was defined as normal left ventricular ejection fraction (LVEF ≥ 50%) and a summed stress score (SSS) of 1-3 vs SSS = 0 in normal MPI. Borderline ischemia was defined as normal LVEF, SSS = 1-3, and a summed difference score (SDS) of 1 vs SDS = 0 in the absence of ischemia. Coronary angiography data within 6 months from MPI were tabulated. Patients were followed for cardiac death (CD), myocardial infarction (MI), coronary revascularization (CR), and Late CR (LCR) [> 90 days post MPI]. Among 6,802 patients (mean age, 62 ± 13 years; 42% men), followed for a mean of 2.5 ± 2.1 years, 4,398 had normal MPI, 2,404 had near-normal MPI, and 972 had borderline ischemia. Among patients who underwent angiography within 6 months, obstructive (≥ 70% or left main ≥ 50%) CAD was observed at higher rates among subjects with near-normal MPI (33.5% vs 25.5%; P = .049) and those with borderline ischemia (40.5% vs 25.8%; P = .004). During follow-up, 158 (2.3%) CD/MI, 246 (3.6%) CR, and 150 (2.2%) LCR were observed. Near-normal MPI (SSS = 1-3), compared to normal MPI (SSS = 0), was not associated with a significant difference in the risk of the composite endpoint of CD/MI (Hazard ratio [HR], 1.21; 95% confidence interval [CI], .88-1.66; P = .243) or LCR (HR 1.28; CI .93-1.78; P = .130), but was associated with a significant increase in the risk of CR (HR 1.91; CI 1.49-2.46; P < .001). Borderline ischemia (SDS = 1), compared to no ischemia (SDS = 0), was not associated with a significant difference in the risk of CD/MI [HR 1.09; CI .70-1.69; P = .693], but was associated with a significant increase in the risk of CR (HR 5.62; CI 3.08-10.25; P < .001) and LCR (HR 2.98; CI 1.36-6.53; P = .006).

CONCLUSION

Near-normal MPI and borderline ischemia on SPECT-MPI provide no significant prognostic information in predicting hard cardiac events but are associated with higher rates of obstructive angiographic CAD and coronary revascularizations.

The prognostic utility of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease: The largest cohort to date

BACKGROUND

There are limited data on the prognostic utility of regadenoson SPECT myocardial perfusion imaging (MPI) in patients with end-stage renal disease (ESRD).

METHODS AND RESULTS

In a single-center, retrospective study, we analyzed consecutive ESRD patients who underwent regadenoson SPECT-MPI. The severity of MPI abnormalities and ischemic burden were determined quantitatively. The primary endpoint was major adverse cardiac events (MACE), defined as the composite of cardiac death or myocardial infarction. Among 1,227 subjects (mean age 54 ± 13 years, 47% men), 60 (5%) MACE were observed during a mean follow-up of 2.5 ± 1.8 years. The presence and severity of MPI abnormalities and ischemic burden were associated with a stepwise increase in MACE risk. Abnormal MPI (SSS ≥ 4) was associated with increased MACE risk, independent and incremental to relevant clinical covariates; adjusted hazard ratio, 1.95; 95% confidence interval, 1.15-3.32; Δχ2 = 5.97; P = .013. Myocardial ischemia (SDS ≥ 2) was associated with a trend towards increased MACE risk; adjusted hazard ratio, 1.63; 95% confidence interval, 0.96-2.77; Δχ2 = 3.12; P = .072.

CONCLUSION

In the largest cohort to date, we demonstrated the incremental prognostic value of abnormal MPI in predicting MACE risk in ESRD patients. Given its size, our study provides improved risk estimates in this population compared to previous reports.

The prognostic value of regadenoson SPECT myocardial perfusion imaging: The largest cohort to date

BACKGROUND

Data on the prognostic value of regadenoson SPECT myocardial perfusion imaging (MPI) is limited and based on small cohorts.

METHODS AND RESULTS

We conducted a single-center, retrospective cohort study of 10,275 consecutive patients who underwent regadenoson SPECT-MPI. Among the study subjects, 28.7% had abnormal MPI and 25.5% had myocardial ischemia. Patients were followed for a mean of 2.4 ± 2.2 years for major adverse cardiac events (MACE), defined as cardiac death or myocardial infarction. There was a significant stepwise increase in MACE with an increasing burden of perfusion abnormality (P < .001) and myocardial ischemia (P < .001). Abnormal MPI (adjusted HR 1.52; 95% CI 1.21 to 1.91) and myocardial ischemia (adjusted HR 1.53; 95% CI 1.25 to 1.89) were associated with MACE, independent of and incremental to clinical covariates and left ventricular ejection fraction (LVEF). Moreover, post-stress LVEF, LVEF reserve, and left ventricular end-diastolic volume added significant prognostic information. Transient ischemic dilation ≥ 1.31 did not provide incremental prognostic value (adjusted HR 1.02; P = .906).

CONCLUSION

In the largest cohort to date, we demonstrated that the presence and severity of perfusion abnormality and myocardial ischemia on regadenoson stress SPECT-MPI are associated with an independent increase in MACE.

Prognostic value of regadenoson stress myocardial perfusion imaging in patients with left bundle branch block or ventricular paced rhythm

BACKGROUND

Vasodilator stress myocardial perfusion imaging (MPI) is the provocative test of choice in patients with left bundle branch block (LBBB) or ventricular paced (V-paced) rhythm. The prognostic value of regadenoson SPECT myocardial perfusion imaging (MPI) in these patients has not been studied.

METHODS AND RESULTS

We conducted a retrospective cohort study of 562 patients [mean age, 69 ± 11 years; men, 53.3%] with LBBB (50.7%) or V-paced rhythm (49.3%) who underwent regadenoson stress SPECT-MPI. There were 321 (57.1%) subjects with abnormal MPI and 192 (34.2%) with myocardial ischemia. During a mean follow-up of 2.5 ± 1.9 years, 39 (6.9%) patients had a major adverse cardiac event (MACE), defined as cardiac death or myocardial infarction. The annualized MACE rate in patients with normal MPI was 0.9% (LBBB, 0.8%; V-paced, 1.0%). There was a significant stepwise increase in MACE rates with increasing burdens of perfusion abnormality (P < 0.001) and myocardial ischemia (P = 0.001). Increased risk with abnormal MPI [adjusted hazard ratio, 4.26; P = 0.001] and myocardial ischemia [adjusted hazard ratio, 2.70; P = 0.003] was independent of and incremental to important clinical covariates. Abnormal MPI and myocardial ischemia predicted MACE similarly in both LBBB and V-paced subgroups (interaction P values > 0.05).

CONCLUSION

In patients with LBBB and V-paced rhythm, regadenoson stress SPECT-MPI provides independent and incremental prognostic value in predicting adverse cardiac events.

Prognostic significance of post-stress reduction in left ventricular ejection fraction with adenosine stress in Jordanian patients with normal myocardial perfusion

BACKGROUND

The significance of post-stress reduction in left ventricular ejection fraction (LVEF) in patients with normal perfusion on adenosine stress/rest imaging remains controversial.

METHODS

Consecutive patients who underwent 2-day adenosine gated stress/rest 99mTc-sestamibi imaging and had normal perfusion were analyzed. LVEF was quantified at rest and 1 hour post-adenosine. Patients were followed up for hard (cardiac death or nonfatal MI) and soft (coronary revascularization or congestive heart failure) cardiac events for 24.1 ± 11.0 months.

RESULTS

Of 560 patients included in the study, 135 (24.1%) had a post-stress reduction in LVEF of ≥ 5%. Rest LVEF (P < 0.001), known history of CAD (P = 0.01) and transient ischemic dilatation ratio (P = 0.02) were independent predictors of LVEF reduction. Event-free survivals were similar in patients with and without ≥ 5% LVEF reduction (P = 0.8). The unadjusted hazard ratio (95% CI) for cardiac events for ≥ 5% LVEF reduction was 1.09 (0.55-2.15), P = 0.81, while the hazard ratio adjusted for known history of CAD, smoking, post-stress LVEF and peak heart rate was 0.87 (0.44-1.75), P = 0.71.

CONCLUSIONS

Significant post-adenosine reduction in LVEF occurs in about one-fourth of patients with normal perfusion but does not confer adverse prognosis compared with patients without such reduction.

Prognostic significance of ischemic electrocardiographic changes with regadenoson stress myocardial perfusion imaging

BACKGROUND

In patients undergoing regadenoson SPECT myocardial perfusion imaging (MPI), the prognostic value of ischemic ST-segment depression (ST↓) and the optimal ST↓ threshold have not been studied.

METHODS

A retrospective cohort study of consecutive patients referred for regadenoson stress MPI was conducted. Patients with uninterpretable ECG were excluded. Two diagnostic thresholds of horizontal or downsloping ST↓ were studied, ≥ 0.5 mm and ≥ 1.0 mm. The primary endpoint was the composite major adverse cardiac events (MACE) of cardiac death, myocardial infarction, or coronary revascularization.

RESULTS

Among 8615 subjects (mean age 62 ± 13 years; 55% women), 89 (1.0%) had ST↓ ≥ 1.0 mm and 133 (1.5%) had ST↓ ≥ 0.5 mm. Regadenoson-induced ST↓ was more common in women (P < .001). Mean follow-up was 2.5 ± 2.2 years. After multivariate adjustment, ST↓ ≥ 1.0 mm was associated with a non-significant increase in MACE risk (P = .069), irrespective to whether MPI was abnormal (P = .162) or normal (P = .214). Ischemic ST↓ ≥ 0.5 mm was independently associated with MACE in the entire cohort (HR 2.14; CI 1.38-3.32; P = .001), whether MPI is normal (HR 2.07; CI 1.07-4.04; P = .032) or abnormal (HR 2.24; CI 1.23-4.00; P = .007), after adjusting for clinical and imaging covariates. An ST↓ threshold of ≥ 0.5 mm provided greater incremental prognostic value beyond clinical and imaging parameters (Δχ2 = 12.78; P < .001) than ≥ 1.0 mm threshold (Δχ2 = 3.72; P = .093).

CONCLUSION

Regadenoson-induced ischemic ST↓ is more common in women and it provides a modest independent prognostic value beyond MPI and clinical parameters. ST↓ ≥ 0.5 mm is a better threshold than ≥ 1.0 mm to define ECG evidence for regadenoson-induced myocardial ischemia.

Diagnosis and Prognosis of Coronary Artery Disease with SPECT and PET

PURPOSE OF REVIEW

Radionuclide myocardial perfusion imaging (MPI) continues to be the most reliable modality for diagnosis of hemodynamically significant coronary artery disease (CAD). The application of radionuclide MPI using single photon emission computed tomography (SEPCT) and positron emission tomography (PET) for CAD is reviewed, with emphasis on diagnosis and risk stratification.

RECENT FINDINGS

Contemporary studies have reported the diagnostic and prognostic value of novel imaging protocols, employing stress-first or stress-only approach. In addition, the superior diagnostic value of PET has been established with a role of assessment of myocardial blood flow to improve risk stratification. The utility of MPI in special populations, such as the elderly, women, and diabetic patients has also been recently evaluated. Furthermore, multicenter studies have reported a similar diagnostic and prognostic value of radionuclide MPI compared with other functional and anatomical techniques for CAD. Radionuclide MPI with SPECT and PET are efficacious for diagnosis and prognosis of CAD. Its universal application in varied patient populations highlights its excellent clinical effectiveness.

Deciding wisely: A case for an effective use of myocardial perfusion imaging

There is a vast body of literature supporting the use of stress myocardial perfusion imaging (MPI) in patients with known or suspected coronary artery disease. When applied in the appropriate clinical setting, MPI can aid, not only in diagnosis and risk stratification, but also in decision-making. In a case of a 58-year-old man with suspected coronary artery disease, we highlight how the appropriate use of stress MPI can leverage the diagnostic and prognostic utility of MPI in an effective, evidence-based decision-making aimed to achieve the best patient outcome.

Clinical value of hyperemic left ventricular systolic function in vasodilator stress testing

Exercise results in increased left ventricular contractility in normal individuals. Similar changes can also be seen with vasodilator stress. This article discusses the physiologic basis of these changes as well as reviews the clinical data supporting the use of these parameters for diagnostic and prognostic evaluation. Methodologic limitations as well as other concomitant pathologic processes which may confound interpretation of stress-induced changes in LVEF are also reviewed.