Gated SPECT myocardial perfusion imaging, intraventricular synchronism, and cardiac events in heart failure

Prognostic value of mechanical dyssynchrony in patients with heart failure: a systematic review

BACKGROUND

Heart failure (HF) significantly impacts quality of life and healthcare systems worldwide. Assessing left ventricular mechanical dyssynchrony (LVMD) is crucial for understanding cardiac function and optimizing treatments like cardiac resynchronization therapy (CRT). Phase analysis using gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has shown promise in predicting outcomes, yet recent comprehensive reviews are lacking.

OBJECTIVE

To systematically assess the prognostic value of phase analysis by gated SPECT MPI in the HF population through a systematic review.

METHODS

We conducted a systematic review by collecting studies from databases including PubMed, CINAHL, and Web of Science. Two reviewers independently performed study selection, data extraction, and risk of bias assessment. Systematic reviews were conducted using Review Manager Software 5.4 and STATA 16.0.

RESULTS

A total of 2004 patients from seven studies were included in our review and analysis. The systematic review indicated that patients with predetermined clinical events had higher PSD [MD = 6.45, 95% CI (5.83, 7.07), p < 0.00001] and PBW [MD = 7.91, 95% CI (5.64, 10.19), p < 0.00001]. The diagnosis of LVMD determined by PSD [HR = 1.05, 95% CI (1.01, 1.08), p = 0.007] was a strong predictor of endpoint events compared to PBW [HR = 1.95, 95% CI (0.48, 7.89), p = 0.35].

CONCLUSIONS

The analysis demonstrated that phase information obtained from gated SPECT MPI is of significant prognostic value in patients with heart dysfunction. It effectively enhances clinical risk models, providing reliable guidance for patient treatment.

MULTIMODAL LOGIT MODEL FOR PREDICTING THE EFFICIENCY OF MYOCARDIAL REVASCULARIZATION BY THE METHOD OF CORONARY ARTERY BYPASS GRAFTING IN PATIENTS WITH CORONARY HEART DISEASE

OBJECTIVE

building of a mathematical logit model for possible prediction of the outcome of surgical treatment bythe method of coronary artery bypass grafting (CABG) in patients of different groups with coronary heart disease(CHD) based on myocardial viability (MV) assessment.

MATERIAL AND METHODS

To implement the set clinical tasks, 62 patients with coronary heart disease with preservedsystolic function and systolic dysfunction were examined. The mean age of the subjects was (59.6 ± 8.2) years. 35(56 %) patients had a variant of heart failure (HF) with an ejection fraction (EF) of 45 % or less. 27 (44 %) patientshad EF of 46 % or more. 5 (8.0 %) patients denied myocardial infarction (MI). Myocardial scintigraphy (MSG) wasperformed on Infinia Hawkeye combined gamma-camera (GE, USA) with integrated CT. The studies were performedin SPECT and SPECT / CT with ECG synchronization (Gated SPECT) modes. 99mTc-MIBI with an activity of 555-740 MBqwas used. MSG was performed in the dynamics of treatment (before CABG and after CABG) according to One Day Restprotocol. A total of 124 scintigraphic studies were performed.

RESULTS

Samples of patients studied «before» and «after» the treatment were compared using nonparametricWilcoxon test (Wilcoxon Matched Pairs Test). A multivariate regression model, that reflects a statistically significanteffect on the treatment response (MV after treatment) of such cardiac activity indicators as LV EF (%), coronary bedlesion area and MV level (%) before treatment, was built. The above-described regression relationship between thethree above-defined functional factors of cardiac activity before treatment and the therapeutic effect in the formof the change in MV can be construed as a diagnostic model that predicts the treatment outcome.

CONCLUSIONS

This scientific study allows to build logit models to predict the expected outcome of coronary heartdisease surgical treatment in patients of different groups. The presented multivariate regression model is characterised by a sufficiently high for biostatistical studies adjusted coefficient of determination (Adjusted R2 = 0,893 (F = 173,4; p < 0,001)).

Mechanisms of left ventricular dyssynchrony: A multinational SPECT study of patients with bundle branch block

BACKGROUND

To better understand the mechanisms of left ventricular (LV) mechanical dyssynchrony (LVMD), we explored the relative contributions of QRS duration (QRSd), LV ejection fraction (EF), volumes and scar to LVMD measured by gated single-photon emission tomography in a population of consecutive patients with left bundle branch block (LBBB) and right bundle branch block (RBBB) compared to controls.

METHODS

Myocardial perfusion imaging studies of 275 LBBB and 83 RBBB patients from three centers were analyzed. LVMD was defined as an abnormal phase bandwidth or phase standard deviation. Hospital and gender-specific normal values were obtained from 172 controls.

RESULTS

The prevalence of LVMD was 85 and 40% in LBBB and RBBB, respectively. Ejection fraction, scar severity, and LBBB morphology independently explained 70% of variance seen in PhaseBW. Ejection fraction had the highest area under the curve (AUC 0.918) in the receiver operating characteristics analysis of LVMD with an optimal cut-off of 47% (sensitivity 73% and specificity 98%). Notably, QRSd was not predictive.

CONCLUSION

LV mechanical dysfunction plays a greater role than conduction abnormality in the genesis of LVMD, a finding that is intriguing in the context of contemporary literature which suggests that QRSd is the parameter that is most predictive of CRT response.

Intraventricular synchronism assessment by gated-SPECT myocardial perfusion imaging in cardiac resynchronization therapy. Does cardiomyopathy type influence results?

Purpose

To analyze the evolution post-cardiac resynchronization therapy (CRT) in left ventricular non-compaction (LVNC) cardiomyopathy (CM) patients compared to other types of CM, according to clinical and functional variables, by using gated-SPECT myocardial perfusion imaging (MPI).

Methods

Ninety-three patients (60 ± 11 years, 28% women) referred for pre-CRT assessment were studied and divided into three groups: 1 (non-ischemic CM with LVNC, 11 patients), 2 (ischemic CM, 28 patients), and 3 (non-ischemic CM, 53 patients). All were studied by a ^99mTc-MIBI gated-SPECT MPI at rest pre-CRT implantation and 6 ± 1 months after, including intraventricular dyssynchrony assessment by phase analysis. Quality of life was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ).

Results

No differences in sex, atherosclerotic risk factors other than smoking habit, and MLHFQ results were found among groups. LVNC CM patients were younger, with greater QRS width and lower left ventricular ejection fraction (LVEF) at baseline, but the differences were not significant. No significant differences were found at baseline regarding ventricular function, although end-systolic volume was slightly higher in LVNC CM patients. Mean SRS was significantly higher (p < 0.0001) in ischemic patients (14.9) versus non-ischemic ones (8.7 in group 1 and 9 in group 2). At baseline, LVNC CM patients were significantly more dyssynchronous: Their phase standard deviation (PSD) was higher (89.5° ± 14.2°) versus groups 2 (65.2° ± 23.3°) and 3 (69.7° ± 21.7°), p = 0.007. Although the quality of life significantly improved in all groups, non-ischemic patients (with or without LVNC) showed a higher LVEF increase and volumes reduction at 6 months post-CRT. Dyssynchrony reduced post-CRT in all groups. Nevertheless, those more dyssynchronous at baseline (LVNC CM) exhibited the most significant intraventricular synchronism improvement: PSD was reduced from 89.5° ± 14.2° at baseline to 63.7° ± 20.5° post-CRT (p = 0.028). Six months post-CRT, 89% of patients were responders: 11 (100%) of those with LVNC CM, 25 (86%) of those with ischemic CM, and 47 (89%) of patients with non-ischemic CM. No patient with LVNC CM had adverse events during the follow-up.

Conclusion

CRT contributes to a marked improvement in non-ischemic CM patients with non-compaction myocardium. Phase analysis in gated-SPECT MPI is a valuable tool to assess the response to CRT.

Could myocardial viability be related to left ventricular dyssynchrony? Simultaneous evaluation by gated SPECT-MPI

BACKGROUND

Left ventricular contraction dyssynchrony (LVCD) has been related to induced ischemia and transmural scar but the interplay of myocardial viability and dyssynchrony is unknown. The aim of the present study was to establish the role of dyssynchrony in the context of a viability study performed with nitrate augmentation gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI).

METHODS

Fifty-four consecutive patients with ischemic dilated cardiomyopathy (IDC) and depressed left ventricular ejection fraction (LVEF) were included. They underwent a two-day rest/nitroglycerine (NTG) study GSPECT MPI to determine the myocardial viability. Patients with a nitrate-induced uptake increase of > 10% vs baseline, in at least, two consecutive dysfunctional segments were considered viable as well as those who showed no improvement in the uptake but the uptake was > 50% on post NTG study. Patients with no nitrate-induced uptake increase of > 10% and the uptake of < 50% were considered non-viable. Perfusion, function and LVCD were compared in 25 viable patients vs 29 non-viable patients at baseline and after NTG administration.

RESULTS

After NTG administration, in the viable group, the LVEF increased (36.44 ± 6.64% vs 39.84 ± 6.39%) and the end-systolic volume decreased significantly (119.28 ± 31.77 mL vs 109.08 ± 33.17 mL) (P < 0.01). These patients also experienced a significant reduction in the LVCD variables: phase standard deviation was reduced in the post NTG study (57.77° ± 19.47° vs 52.02° ± 17.09°) as well as the phase histogram bandwidth (190.20° ± 78.83° vs 178.0° ± 76.14°) (P < 0.05). Functional and LVCD variables remained similar in the non-viable patients (P > 0.05).

CONCLUSION

In patients with IDC and depressed LVEF, the myocardial viability detected by rest/ NTG GSPECT MPI, might determine LVCD improvement.

Phase analysis for the assessment of left ventricular dyssynchrony by Gated Myocardial Perfusion SPECT. Importance of clinical and technical parameters

Introducción. El análisis de fase (AF) del ventrículo izquierdo es una herramienta de reciente introducción en los estudios de cardiología nuclear, que permite valorar el sincronismo mecánico de la contracción del ventrículo izquierdo con diferentes aplicaciones clínicas, si bien es poco conocida.Objetivo. Mostrar la factibilidad de la nueva herramienta AF por perfusión miocárdica (Gated-SPECT) para valorar el sincronismo mecánico del ventrículo izquierdo y verificar diferencias entre sus valores, según situaciones clínicas y condiciones técnicas.Materiales y métodos. En el estudio participaron pacientes consecutivos con Gated-SPECT. Las variables principales fueron diferentes condiciones clínicas y técnicas. La valoración del AF se realizó mediante la herramienta FASE del programa cardiodedicado (QPS-QGS, Cedars-Sinai Medical Center, Los Angeles, USA). Se obtuvieron los siguientes parámetros: ancho del histograma (AH), desviación estandar de la fase (DE) y entropía (E). Se realizó análisis descriptivo y analítico de medias o medianas a través de test paramétricos o no paramétircos. El límite de significancia estadísitca fue p<0.05. Se utilizó IBM-SPSS V21®.Resultados. Con un total de 300 pacientes y una media de edad de 65±12.7, en el análisis del AF no existieron diferencias según la fase del estudio (estrés-reposo) [AH (p=0.4), DE (p=0.6), E (p=0.7)], tipo de estrés [AH (p=0.38), DE (p=0.8), E (p=0.84)], dosis utilizada [AH(p=0.19), DE (p=0.05), E (p=0.06)], gammacámara [AH (p=0.02), DE (p=0.06), E (p=0.08)] ni entre antecedente de enfermedad coronaria [AH (p=0.44), DE (p=0.18), E (p=0.17)].Hubo diferencias según trastornos de conducción [AH (p=0.001), DE (p=0.02), E (p=0.001)], fracción de eyección < o >35% [AH (p=0.001), DE (p=0.001), E (p=0.001)], estudio normal o con necrosis [AH (p=0.001), DE (p=0.001), E (p=0.001)] y género [AH (p=0.002), DE (p=0.006), E (p=0.005)].Conclusiones. El uso de la nueva herramienta del AF de medicina nuclear es factible. Sus parámetros no se afectaron por el tipo de estrés producido, dosis administrada o fase del estudio por la gammacámara empleada. Por su parte, sí fueron afectados por género, trastornos de conducción interventricular, necrosis y disfunción sistólica.