Effects of left ventricular size on the accuracy of diastolic parameters derived from myocardial perfusion SPECT: comparison with tissue Doppler echocardiography

Diagnostic value of parameters derived from planar MUGA for detecting HFpEF in coronary artery disease patients

BACKGROUND

In recent years, heart failure with preserved ejection fraction (HFpEF) has received increasing clinical attention. To investigate the diagnostic value of diastolic function parameters derived from planar gated blood-pool imaging (MUGA) for detecting HFpEF in coronary atherosclerotic heart disease (coronary artery disease, CAD) patients.

METHODS

Ninety-seven CAD patients with left ventricular ejection fraction ≥ 50% were included in the study. Based on the left ventricular end-diastolic pressure (LVEDP), the patients were divided into the HFpEF group (LVEDP ≥ 16 mmHg, 47 cases) and the normal LV diastolic function group (LVEDP < 16 mmHg, 50 cases). Diastolic function parameters obtained by planar MUGA include peak filling rate (PFR), filling fraction during the first third of diastole (1/3FF), filling rate during the first third of diastole (1/3FR), mean filling rate during diastole (MFR), and peak filling time (TPF). Echocardiographic parameters include left atrial volume index (LAVI), peak tricuspid regurgitation velocity (peak TR velocity), transmitral diastolic early peak inflow velocity (E), average early diastolic velocities of mitral annulars (average e'), average E/e' ratio. The diastolic function parameters obtained by planar MUGA were compared with those obtained by echocardiography to explore the clinical value of planar MUGA for detecting HFpEF.

RESULTS

The Receiver-operating characteristic curve analysis of diastolic function parameters obtained from planar MUGA and echocardiography to detect HFpEF showed that: among the parameters examined by planar MUGA, the area under the curve (AUC) of PFR, 1/3FF, 1/3FR, MFR and TPF were 0.827, 0.662, 0.653, 0.663 and 0.809, respectively. Among the echocardiographic parameters, the AUCs for average e', average E/e' ratio, peak TR velocity, and LAVI values were 0.747, 0.706, 0.735, and 0.633. The combination of PFR and TPF showed an AUC of 0.856. PFR combined with TPF value demonstrated better predictive value than average e' (Z = 2.020, P = 0.043).

CONCLUSION

Diastolic function parameters obtained by planar MUGA can be used to diagnose HFpEF in CAD patients. PFR combined with TPF was superior to the parameters obtained by echocardiography and showed good sensitivity and predictive power for detecting HFpEF.

Changes in left ventricle myocardial volume during stress test using cadmium-zinc-telluride cardiac imaging: Implications in coronary artery disease

BACKGROUND

Cadmium-zinc-telluride (CZT) SPECT allows the estimation of left ventricle myocardial volume (LVMV). We tested the clinical relevance of rest-stress LVMV changes (Δ LVMV) in detecting coronary artery disease (CAD, coronary stenosis > 70%), using CZT-SPECT.

METHODS

We prospectively enrolled 512 consecutive patients with known or suspected CAD (mean age: 70.3 ± 9.2 years, 72% male) for stress-rest myocardial perfusion imaging (MPI, single-day stress-rest protocol). We quantified summed stress scores (SSS), summed rest scores, and summed difference scores, together with LVMV and ejection fraction (EF) after stress and at rest. All patients underwent coronary angiography within 30 days.

RESULTS

Two hundred seventy-two patients had CAD at coronary angiography. ΔLVMV ≤ 5 mL, corresponding to 6% of change from rest LVMV, was the best predictor of CAD (AUC = 0.831, 79% sensitivity, 82% specificity), irrespective of the stress protocol (dipyridamole or exercise stress) and independently of MPI-SSS, LV EF, and clinical history (P = 0.004). Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were significant for the addition of ΔLVMV ≤ 5 mL (IDI = 6.1%, P < 0.0001; NRI = 29.7%, P = 0.02) to MPI-SSS, whereas the other parameters were not.

CONCLUSIONS

The evaluation of ΔLVMV using CZT-SPECT can improve the diagnostic accuracy in predicting the presence of CAD when added to conventional MPI.

Diagnostic value of peak filling rate derived from ECG-gated myocardial perfusion SPECT for detecting myocardial ischaemia in patients with non-obstructive coronary artery disease

Background: Left ventricular (LV) diastolic dysfunction represents an earlier step of the ischaemic cascade. We tested the hypothesis that the index of LV diastolic function from electrocardiogram (ECG)-gated single photon emission computed tomography (SPECT) is useful in detecting myocardial ischaemia in patients with non-obstructive coronary artery disease (CAD).Methods: One-hundred-ten patients with non-obstructive CAD and summed redistribution score of zero were enrolled. Summed difference score (SDS) of ≥2 was considered as the presence of myocardial ischaemia. Peak filling rate (PFR) defined as the maximum dV/dt divided by LV end-diastolic volume was obtained as the index of LV diastolic function.Results: Of 110 patients with non-obstructive CAD, 51 patients had myocardial ischaemia. SDSs in patients with myocardial ischaemia and those without were 3.5 ± 1.8 and 0.4 ± 0.5, respectively (p < 0.001). PFRs after stress (r = -0.22, p = 0.02) and at redistribution (r = -0.24, p = 0.01) were inversely correlated with SDS. Multivariate logistic regression analysis showed that PFR at redistribution was an independent predictor of the presence of myocardial ischaemia in patients with non-obstructive CAD (odds ratio: 0.15, 95% confidence interval: 0.04-0.51, p = 0.002).Conclusion: Our data suggest that PFR, the index of LV diastolic function from ECG-gated SPECT, helps to find myocardial ischaemia in patients with non-obstructive CAD.

Associations of left ventricular shape with left ventricular volumes and functions assessed by ECG-gated SPECT in patients without significant perfusion abnormality

Left ventricular (LV) remodeling often results from conditions with an elevated LV hemodynamic load or after myocardial infarction. The present study was undertaken to investigate the associations of LV shape with LV volumes and functions in patients without significant perfusion abnormality. One hundred and sixty-seven patients without significant perfusion abnormality on ECG-gated SPECT were enrolled. LV ejection fraction (LVEF) was obtained for assessing LV systolic function. Peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained for assessing LV diastolic function. LV shape index (LVSI) was defined as the ratio of the maximum three-dimensional short- and long-axis LV dimension, and varies from 0 (line) to 1 (sphere). There were 125 male and 42 female patients with a mean age of 70 ± 8 years. End-systolic LVSI was 0.49 ± 0.07 (0.34-0.65). End-systolic LVSI was associated with LV end-diastolic volume (r = 0.51, p < 0.001) and LV end-systolic volume (LVESV) (r = 0.64, p < 0.001), and was inversely associated with LVEF (r = - 0.69, p < 0.001), PFR (r = - 0.45, p < 0.001) and 1/3 MFR (r = - 0.26, p = 0.008). End-systolic LVSI was increased with increased LVESV, and was not any more with LVESV of > 40 ml. Multivariate liner regression analysis showed that age (β = 0.16, p = 0.01), LVESV (β = 0.20, p = 0.03) and LVEF (β = - 0.53, p < 0.001) were significantly associated with end-systolic LVSI. Our data suggest that end-systolic LVSI, a measurement of LV shape, has close correlations with LV volumes and functions in patients without significant perfusion abnormality.

Implications of electrocardiographic frontal QRS axis on left ventricular diastolic parameters derived from electrocardiogram-gated myocardial perfusion single photon emission computed tomography

BACKGROUND

Current electrocardiographic (ECG) machines report various variables including frontal QRS axis automatically. We tested the hypothesis that QRS axis is associated with left ventricular (LV) diastolic parameters derived from ECG-gated myocardial perfusion single photon emission computed tomography (SPECT) independent of myocardial ischemia.

METHODS

Ninety-three patients with preserved LV ejection fraction and no evidence of myocardial ischemia were enrolled based on ECG-gated SPECT. Peak filling rate (PFR), one-third mean filling rate (1/3 MFR) and time to peak filling (TTPF) were obtained as LV diastolic parameters.

RESULTS

There were 82 male and 11 female patients with a mean age of 69 ± 9 years. QRS axis ranged from - 40° to 85° (36° ± 31°). QRS axis was correlated with PFR (r = 0.28, p < 0.01), 1/3 MFR (r = 0.25, p = 0.02) and TTPF (r = - 0.21, p = 0.04). QRS axis was also correlated with age (r = - 0.23, p = 0.03), body mass index (BMI) (r = - 0.36, p < 0.01) and LV mass index (LVMI) (r = - 0.27, p < 0.01). Linear regression analysis showed that QRS axis was associated with PFR, 1/3 MFR and TTPF for LV diastolic function, but was not associated with these LV diastolic parameters after adjustment of various confounders.

CONCLUSIONS

Our data suggest that QRS axis depends on age, BMI or LVMI, and serves as a surrogate marker of LV diastolic function.

Left ventricular functional parameters by gated SPECT myocardial perfusion imaging in a Latin American country

BACKGROUND

There is paucity of data on left ventricular (LV) functional parameters using gated SPECT myocardial perfusion imaging (MPI) from the Latin American region. This study provides detailed information in low-risk patients both at rest and during exercise.

METHODS AND RESULTS

We studied 90 patients (50 men) with a very low likelihood of coronary artery disease. Gated-SPECT MPI was performed with Tc-99m MIBI using a 2-day protocol, with 16 frames/R-R cycle. The LV ejection fraction and volumes were not different between the rest and post-stress images. LVEF was 68 ± 7% post-stress and 70 ± 7% at rest in women, and 62 ± 7% and 63 ± 7%, respectively, in men (P = .19, .26). LV volumes were larger in men than women (P < .01). There were no differences in most variables obtained at rest or post-stress. Transient ischemic dilatation was similar, with upper limits of 1.20 and 1.19 in women and men, respectively (P = NS).

CONCLUSIONS

These data could prove helpful for the interpretation of gated SPECT MPI data in Latin America using identical protocol as used in this study.

Effects of aortic tortuosity on left ventricular diastolic parameters derived from gated myocardial perfusion single photon emission computed tomography in patients with normal myocardial perfusion

Aortic tortuosity is often found on chest radiograph, especially in aged patients. We tested the hypothesis that aortic tortuosity was associated with LV diastolic parameters derived from gated SPECT in patients with normal myocardial perfusion. One-hundred and twenty-two patients with preserved LV ejection fraction and normal myocardial perfusion were enrolled. Descending aortic deviation was defined as the horizontal distance from the left line of the aortic knob to the most prominent left line of the descending aorta. This parameter was measured for the quantitative assessment of aortic tortuosity. Peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained from redistribution images as LV diastolic parameters. Descending aortic deviation ranged from 0 to 22 mm with a mean distance of 4.5 ± 6.3 mm. Descending aortic deviation was significantly correlated with age (r = 0.38, p < 0.001) and estimated glomerular filtration rate (eGFR) (r = - 0.21, p = 0.02). Multivariate linear regression analysis revealed that eGFR (β = 0.23, p = 0.02) and descending aortic deviation (β = - 0.23, p = 0.01) were significantly associated with PFR, and that only descending aortic deviation (β = - 0.21, p = 0.03) was significantly associated with 1/3 MFR. Our data suggest that aortic tortuosity is associated with LV diastolic parameters derived from gated SPECT in patients with normal myocardial perfusion.