SPECT and PET myocardial perfusion imaging in Austria, Germany, and Switzerland results of the first joint survey of 2021

PURPOSE

This paper presents the results of the first joint survey on the use of SPECT and PET myocardial perfusion imaging (MPI) and cardiac amyloidosis imaging in Austria, Germany, and Switzerland of the year 2021.

METHODS

A questionnaire was sent in 2022 to centres practicing nuclear medicine.

RESULTS

Data from 14 Austrian (10,710 SPECT), 218 German (133,047 SPECT), and 16 Swiss centres (11,601 MPI (6,879 SPECT, 4722 PET)) were analysed. In Austria and Germany, the PET MPI numbers were close to zero and not considered. Official MPS numbers from 2015 to 2021 from Austria and Germany revealed a decline in Austria by about 40% in the pandemic years 2020 to 2021, but an increase in Germany by 9%. Ambulatory care cardiologists represented the major referral group (56-71%). Mostly, stress tests were performed pharmacologically (58-92%). Contrary to Germany, a 1-day protocol was predominant (58-97%) in Austria and Switzerland. The leading camera systems were SPECT-CT in Austria and Switzerland (57-79%) and multi-head systems in Germany (58%). Switzerland had the highest proportion of SPECT MPI with attenuation correction (84%), followed by Austria (43%), and Germany (33%). Electrocardiogram-gated SPECT MPI showed an overall high penetration of 87-99%. Scoring was most frequently applied in Germany (72%), followed by Austria (64%), and Switzerland (60%). Related to the population, the number of cardiac amyloidosis imaging was highest in Austria, followed by Switzerland and Germany.

CONCLUSIONS

This first joint survey of 2021 shows considerable differences among the countries. The Swiss situation is outstanding due to the wide use of PET MPI. In terms of camera equipment, Switzerland is also leading, followed by Austria and Germany. Despite the differences in procedural issues, the results reveal an overall high standard of MPI imaging.

Association of serum MMP9 with adverse features of plaque progression in patients with chronic coronary syndrome (CCS)

Background

Previous studies have demonstrated that MMP-9 may be a predictor of atherosclerotic plaque instability and future adverse cardiovascular events, but longitudinal data on the association between MMP9 and coronary disease progression are lacking.

Purpose

This study is aimed at investigating whether MMP9 is associated with atherosclerotic plaque progression.

Methods

MMP9 serum levels were measured in stable patients with chronic coronary syndrome (CCS) undergoing coronary computed tomography angiography at baseline and after a period of 6.5±1.1 years of follow up to assess progression of Total, Fibrous, Fibro-fatty, Necrotic Core, and Dense Calcium plaque volume (PV). The relationship of serum MMP9 with plaque progression was assessed using linear regression analysis, adjusting for clinical variables including, age, sex, risk factors, medical therapy, LDL-C, TG/HDL-C ratio, hs-CRP, and the presence of obstructive CAD (>50% coronary stenosis in at least one major coronary vessels).

Results

A total of 157 patients (58±8 years of age; 66% males) were included in the analysis, with median MMP9 values of 135±186 mg/dL (mean ± SD). Annual changes of Total, Fibrous-Fatty and Necrotic Core PV were significantly different across MMP9 tertiles (Figure 1). Multivariable linear regression analysis demonstrated a positive association between serum levels of MMP9 and annual change of Total and Necrotic Core PV (Figure 1).

Conclusion

Among patients with CCS, MMP9 serum levels were an independent predictor of progression of coronary plaque burden and, in particular, of adverse plaque features, such as Necrotic Core PV. This association was robust and independent from baseline traditional cardiovascular risk factors and medications, supporting for MMP9 a role as a novel marker of residual coronary risk.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Horizon 2020 - Project “Simulation Modeling of coronary ARTery disease: a tool for clinical decision support–SMARTool”

A common plasma lipidomics signature of cardiometabolic and coronary risk in statin users

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Commission in the H2020 program: Project SMARTool, “Simulation

Modeling of coronary ARTery disease: a tool for clinical decision support—SMARTool”

Background and aims

The coexistence of elevated plasma triglycerides (TG) and low high-density lipoprotein cholesterol (HDL-C) may contribute to the residual cardiometabolic risk of coronary artery disease (CAD) independently of total cholesterol and low-density lipoprotein cholesterol (LDL-C) absolute plasma levels [1]. Aim of this study is to assess whether a high TG/HDL-C ratio is characterized by a specific lipidomics signature in statin users and its relationship with the coronary risk score defined by coronary computed tomography angiography (CTA).

Methods

TG/HDL-C ratio was calculated in 132 patients (68.8±7.7 years, 85 males) with suspected or known CAD referred to coronary CTA and receiving statins treatment in the last 6.3 ± 1.4 years before enrolment. Patients were grouped according to TG/HDL-C ratio quartiles: IQ (≤1.694), IIQ (1.695-2.399), IIIQ (2.400-3.281), and IVQ (>3.282). Coronary CTA exams were analysed according to the modified 17-segment American Heart Association classification [2] and interpretable segments were visually assessed for degree of stenosis and plaque composition. A comprehensive coronary risk score (CTA score) [3], previously validated as predictor of adverse outcome, was calculated in each patient. Except for subjects with normal arteries (CTA score = 0), all patients were classified into 3 groups of CTA score severity:  low (score < 5), intermediate (score 5-20) and high (score > 20) risk [4]. Patient-specific plasma targeted lipidomics was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This approach allowed to quantify 69 circulating lipids encompassing six lipid classes (triacylglycerol [TG], phosphatidylcholine [PC], phosphatidylethanolamine [PE], ceramide [Cer], sphingomyelin [SM], cholesterol ester [CE]). Differential analysis was performed using TG/HDL-C and CTA score annotation.

Results

18 altered lipid species in the group with higher TG/HDL-C ratio were also altered in the group with higher CTA risk score. This common set of lipids is composed of CE(16:0), CE(18:0), PC(38:2), 8 SM [SM(34:2), SM(38:2), SM(41:2), SM(41:1), SM(42:4), SM(42:3), SM(42:1), SM(43:3)], TG(52:1) and 6 PE [PE(34:0), PE(34:1), PE(34:2), PE(36:1), PE(36:2), PE(36:3)], and represents the lipidomics signature associating elevated plasma TG/HDL-C ratio with high CTA risk score in statin users.

Conclusion

In patients with stable CAD under statin treatment, a specific pattern of altered lipids, characterized by reduced plasma levels of cholesterol esters and sphingomyelins and increased levels of triacylglicerols and phosphatidylethanolamines, is associated with high TG/HDL-C ratio and high CTA score. This specific lipidomic signature identifies patients with higher residual cardiometabolic and coronary risk, not tackled by current lipid lowering therapy, unveiling possible new molecular targets of treatment.

Myocardial perfusion scintigraphy for risk stratification of patients with coronary artery disease: the AMICO registry

Funding Acknowledgements

Type of funding sources: None.

onbehalf

AMICO registry

Background. Clinical evidence promotes therapy titration based on patient risk stratification in coronary artery disease (CAD).

Purpose. We assessed the prognostic value of myocardial perfusion scintigraphy (MPS) with cadmium-zinc-telluride in addition to clinical and coronary anatomy analysis.

Methods and Results. We prospectively enrolled 1464 patients (26% females, 69.5 ± 10.4 years) referred for stress-rest MPS. All the patients underwent invasive coronary angiography (1171, 80%) or coronary computed tomography angiography (293, 20%). We defined a composite endpoint of cardiovascular death and non-fatal MI. After a median follow-up of 3.5 years (interquartile range 2 – 6 years), we observed 127 events (Table). Summed stress score (SSS) had the highest accuracy in predicting primary endpoint with a ROC-derived cut-off of SSS > 8 (>10% myocardium). SSS > 8 portended the lowest survival probability at Kaplan–Meier analysis (p < 0.0001; Figure A). The Cox-regression analysis indicated SSS as an independent predictor of the composite endpoint, along with fasting blood glucose and total cholesterol and contrary to coronary anatomy parameters. Patients with SSS > 8 treated with optimal medical therapy (OMT) had the largest area of necrosis, the lower ischemic burden, the most compromised LV systo-diastolic function and the highest LV mass, but received a less aggressive treatment in comparison to early revascularized patients. Survival analysis revealed patients with SSS ≤ 8 had the greater freedom from events, irrespective of the treatment strategy, while the group with SSS > 8 and OMT had the worst outcome, followed by patients with SSS > 8 and early revascolarization (log-rank test: all p < 0.0001). Plotting the estimates from proportional-hazard modelling against SSS (reference level: SSS = 4) shows a risk curve for the primary endpoint that increase for SSS > 4 and reach a plateau for values >12 (Figure B). 

Conclusion. The extension of stress perfusion abnormalities constitutes a robust independent predictor of future adverse events after adjustment for multiple clinical parameters and coronary anatomy analysis. MPS could help refine risk stratification of patients with known or suspected CAD.

Primary and secondary endpoints Variable Total population (n = 1464) SSS > 8 (n = 591) SSS ≤ 8 (n = 873) Hazard Ratio (95% CI)* P-value* Primary endpoint 127 (9) 85 (14) 42 (5) 3.25 (2.25 - 4.70) <0.0001 Cardiovascular death 50 (3) 37 (6) 13 (1) 4.53 (2.41 - 8.51) <0.0001 Non-fatal MI 84 (6) 53 (9) 31 (4) 2.71 (1.75 - 4.22) <0.0001 *The hazard ratio is for the SSS > 8 group as compared with the summed stress score (SSS)≤8 group, and P-values were calculated by the log-rank test and are unadjusted for multiple variables. Abstract Figure

Elevated TG/HDL-C ratio is an independent predictor of outcome and it is associated with CAD progression in patients with stable coronary artery disease

Background

Elevated TG/HDL-C ratio is associated with CVD outcomes in high-risk populations presenting for coronary angiography, but studies were limited in gender-specific populations or in pts with ACS.

Purpose

Aim of this study was to evaluate the prognostic role of TG/HDL-C levels and their association with CAD progression in pts with suspected stable CAD.

Methods

TG/HDL-C ratio was calculated in 545 pts (60±9yrs,330males) with symptoms of stable CAD enrolled in the EVINCI study. 490 pts underwent coronary CTA to assess the presence of CAD (>50%stenosis) and entered a clinical follow up (4.5±0.9yrs). The CVD outcome measure included all cause mortality, non fatal MI, hospitalization for unstable angina or HF. After 6±1yrs, during the SMARTool study, a second CTA was obtained in 171 EVINCI pts and a CTA risk score (based on plaque extent, severity, composition, and location) was calculated at enrolment and at follow up to assess CAD progression (ΔCTA score).

Results

Pts were divided according to TG/HDL-C quartiles: IQ (<1.32), IIQ (1.32–2.03), IIIQ (2.04–3.33), and IVQ (>3.33). As reported in Table, the frequency of male, diabetes, metabolic syndrome and obesity increased among quartiles. Glucidic biomarkers progressively increased from quartile I to IV, while LDL-C decreased. The prevalence of obstructive CAD at CTA did not differ among groups. The CVD endpoint occurred in 7% of pts. At multivariable analyses, high TG/HDL-C ratio (IVQ) was associated with the outcome endpoint independently from presence of obstructive CAD and treatment (HR 3.477, 95% CI 1.181–10.239, P=0.0237). CTA score was significantly higher in pts in IVQ compared to IQ at both SMARTool enrolment and follow up (Figure1). A significantly higher ΔCTA score was observed in pts in III-IVQ compared with those in I-IIQ (Figure2).

Conclusion

Elevated TG/HDL-C ratio is an independent predictor of outcome and it is associated with CAD progression in patients with stable CAD.

Funding Acknowledgement

Type of funding source: Public grant(s) – EU funding. Main funding source(s): “EValuation of INtegrated Cardiac Imaging” - EVINCI [GA number: 222915]; “Simulation Modeling of coronary ARTery disease: a tool for clinical decision support - SMARTool” [GA number: 689068]

P6157Indexed coronary volume - A potential novel low-dose CCTA derived predictor for cardiovascular events

Background

Coronary computed tomography angiography (CCTA) provides incremental prognostic information over traditional risk factors in patients with suspected coronary artery disease. However, little is known about the long-term predictive performance of CCTA-derived coronary volumes and mid-diastolic left ventricular (LV) mass.

Purpose

To assess long-term prognostic value of coronary volumes and mid-diastolic LV mass as novel potential imaging predictors derived from low-dose prospectively ECG-triggered CCTA.

Methods

Consecutive patients with suspected or known coronary artery disease, referred for low-dose CCTA, were included. Patients with previous revascularization were excluded. The following parameters were evaluated: calcium score, segment involvement score (SIS: 1 point for each coronary segment with presence of plaque), coronary volume, mid-diastolic LV mass and coronary volume indexed to LV mass. Major adverse cardiovascular events (MACE) were defined as all-cause death, non-fatal myocardial infarction and revascularization (PCI or CABG). The association between CCTA measures and the occurrence of events was quantified using cox regression hazard and Kaplan Meier analysis.

Results

A total of 147 consecutive patients were included in the study. Of them, 93 (63.3%) were male and 79 (53.7%) hat one or more traditional cardiovascular risk factors. There was a weak but statistical significant inverse correlation between indexed coronary volume and both calcium score (R=-0.3, p=0.01) and SIS (R=-0.24, p=0.005). After a median follow-up of 5.8 years 30 MACE occurred in 25 patients, including 3 deaths, 26 revascularizations and 1 non-fatal myocardial infarction. In univariate cox regression hazard analysis calcium score (HR=12.69, 95% CI 2.99–53.83, p<0.001), SIS (HR=1.66, 95% CI 1.43–1.94, p<0.001), LV mass (HR=1.02, 95% CI 1.01–1.03, p=0.007) and indexed coronary volume (HR=0.89, 95% 0.82–0.96, p=0.004) were associated with outcome. In multivariate analysis, indexed coronary volume, remained an independent predictor for MACE when adjusted for traditional risk factors and SIS (HR=0.93, 95% CI 0.87–1.00, p=0.05), while LV mass did not reach statistical significance (p=0.46). By ROC curve analysis, a value of 21.85 mm3/gr was defined as optimal cutoff for indexed coronary volume. In Kaplan Meier plots, patients with low indexed coronary volume (<21.85 mm3/gr) showed higher event rates (log rank p<0.001) compared to high indexed coronary volume (≥21.85 mm3/gr).

Conclusions

Indexed coronary volume, derived from low-dose CCTA, independently predicts cardiovascular events. Larger studies are mandated to confirm the predictive value of this potential new biomarker.

P6167Low leptin plasma levels are associated with progression of coronary atherosclerosis in patients with stable coronary artery disease from the SMARTool Study

Background

Leptin is an adipokine involved in energy homeostasis and has been related with established vascular risk factors. However, studies on the association of leptin plasma levels with coronary artery disease (CAD) have yielded conflicting results.

Purpose

Aim of the present study was to evaluate the association between leptin plasma levels and presence, severity and progression of coronary atherosclerosis in patients with suspected stable CAD.

Methods

In a cohort of 257 patients with symptoms of stable CAD enrolled in the SMARTool study, coronary computed tomography angiography (CTA), plasma leptin levels and clinical and bio-humoral CAD risk profile (including glucose, lipid and inflammation variables) were obtained at enrolment and after 6±1yrs of follow-up. Sixty-four patients were revascularized and the remaining 193 represent the population for the present study. CTA findings were categorised as no-minimal CAD (<30% stenosis), non-obstructive CAD (30%-50% stenosis) and obstructive CAD (≥50% stenosis in at least one major coronary vessel). A CTA risk score (based on plaque extent, severity, composition, and location) was calculated at baseline and at follow-up to assess coronary atherosclerotic burden and its progression (Δ CTA score≥5).

Results

CTA findings showed obstructive CAD in 11% of patients at baseline and in 15% at follow-up (p<0.0001). CTA risk score, was 8.03±7.80 at baseline and increased to 10.33±8.17 at follow-up (p<0.0001) with CAD progression in 20% of patients. Leptin plasma levels were inversely related with CTA findings both at baseline and follow-up (Figure). In a Cox model, baseline plasma leptin was an independent predictor of CAD progression, after adjustment for clinical risk factors, biomarkers, and treatment (HR 0.572, 95% CI 0.393–0.834, P=0.0037).

Figure 1

Conclusion

Plasma leptin is inversely associated with coronary atherosclerotic burden and disease progression in patients with stable CAD. This association is independent of known factors affecting leptin levels. These results could prompt further investigations on the pathophysiological mechanisms of this association.

Acknowledgement/Funding

EU H2020 research and innovation program under grant agreement No 689068

Cardiac SPECT/CCTA hybrid imaging : One answer to two questions?

Noninvasive cardiac imaging has witnessed tremendous advances in the recent past, particularly with regard to coronary computed tomography angiography (CCTA) where substantial improvements in image quality have been achieved while at the same time patients' radiation dose exposure has been reduced to the sub-millisievert range. Similarly, for single-photon emission computed tomography (SPECT) the introduction of novel cadmium-zinc-telluride-based semiconductor detectors has significantly improved system sensitivity and image quality, enabling fast image acquisition within less than 2-3 min or reduction of radiation dose exposure to less than 5 mSv. However, neither imaging modality alone is able to fully cover the two aspects of coronary artery disease (CAD), that is, morphology and function. Both modalities have distinct advantages and shortcomings: While CCTA may prove a superb modality for excluding CAD through its excellent negative predictive value, it does not allow for assessment of hemodynamic relevance if obstructive coronary lesions are detected. Conversely, SPECT myocardial perfusion imaging cannot provide any information on the presence or absence of subclinical coronary atherosclerosis. This article aims to highlight the great potential of cardiac hybrid imaging that allows for a comprehensive evaluation of CAD through combination of both morphological and functional information by fusing SPECT with CCTA.

Drug-eluting stents and drug-coated balloons in peripheral artery disease

Restenosis remains a major problem after angioplasty in peripheral artery disease despite stenting. It occurs in 30 - 50% / year depending on lesion localization and characteristics. One main reason for restenosis is neointimal hyperplasia, which can be suppressed by the topical administration of antiproliferative drugs. In percutaneous coronary intervention the concept of "local drug delivery" has been used for almost a decade with great success. In recent years, drug-eluting stents and drug coated balloons have also been increasingly used in the treatment of peripheral arterial disease as a consequence of positive results of clinical trails. The following article is an overview of the currently available data of completed trials, ongoing and planned studies. Evidence suggests that "drug-coating technology" is reliable, safe and efficient in reducing the target lesion revascularization and binary restenosis rate significantly. With regard to limb salvage and mortality in critical limb ischemia, there is no benefit shown in current published studies.

Lowering heart rate with an optimised breathing protocol for prospectively ECG-triggered CT coronary angiography

OBJECTIVES

The aim was to prospectively characterise the effect of the level of breath-hold on heart rate in CT coronary angiography (CTCA) with prospective electrocardiogram (ECG) triggering and its impact on coronary artery attenuation.

METHODS

260 patients (86 women; mean age 59 ± 11 years) underwent 64-slice CTCA using prospective ECG triggering. Prior to CTCA, heart rates were recorded during 15 s of breath-hold at three different levels of inspiration (normal, intermediate and deep). The inspiration level with the lowest heart rate was chosen for actual CTCA scanning. Coronary artery attenuation was measured, and the presence of backflow of contrast material into the inferior vena cava (as an indicator of increased intrathoracic pressure) was recorded.

RESULTS

The mean heart rate at breath-hold was significantly different for the three inspiration levels (normal, 60 ± 8 bpm; intermediate, 59 ± 8 bpm; deep, 57 ± 7 bpm; p<0.001). The maximum heart rate reduction in each patient at breath-hold averaged 5.3 ± 5.1 bpm, and was observed at a normal inspiration depth in 23 (9%) patients, at an intermediate inspiration depth in 102 (39%) patients and at deep inspiration in 135 (52%) patients. Overall, there was no association between the level of breath-hold and coronary vessel attenuation (p-value was not significant). However, the backflow of contrast material into the inferior vena cava (n = 26) was found predominantly at deep inspiration levels (p<0.001), and, when it occurred, it was associated with reduced coronary attenuation compared with patients with no backflow (p<0.05).

CONCLUSION

The breath-hold level to best reduce heart rate for CTCA should be individually assessed prior to scanning because a mean heart rate reduction of 5 bpm can be achieved.