Impact of recurrent COVID-19 disease waves on acute myocardial infarction epidemics: results from a regional network

Aims: To assess the impact of COVID-19 related public containment measures during recurrent COVID-19 waves on hospital admission rate for acute myocardial infarction (AMI).Methods and results: Clinical characteristics, reperfusion therapy modalities, COVID-19 status and in-hospital mortality of consecutive AMI patients who were admitted in a regional AMI network were recorded during one year starting in March 2020 and were compared with the year before. The COVID-19 study period encompassed two waves: the first in March-May 2020 and the second in October-December 2020. A total of 1349 AMI patients were hospitalised of which 725 during the pre-COVID period and 624 during the COVID period (incidence rate ratio of 1.16, p = 0,006). The impact was predominantly present in the first wave (32% reduction: n = 204 vs 152) and evanished during the second wave (3% increase (152 vs 156). A similar pattern was observed for ACS with cardiac arrest with a 92% reduction (n = 36 vs 3) during the first wave and no change during the second wave (18 vs 18). After correction for temperature and air quality, COVID-19 epidemic remained associated with a decrease of AMI hospitalisation (p = 0.046). Reperfusion strategy for AMI patients, were comparable between both study periods. The in-hospital mortality between the two periods was comparable (2.6% versus 1.9%), but COVID-19 positive ACS patients (n = 7) had a high mortality rate (14%).Conclusion: COVID-19 related public containment measures resulted during the first wave in a 32% reduction of AMI hospitalisation, but this impact was not visible anymore during the second wave.

FFRct use for acute chest pain triage in the emergency department: a cost-effectiveness analysis

AIMS

To model and assess the cost-effectiveness of CT-based fractional flow reserve (FFRct) for a population of low to intermediate risk patients for coronary artery disease (CAD) presenting to the emergency department (ED) with acute chest pain.

METHODS AND RESULTS

Using a decision tree model with a 1 year time horizon and from a health care perspective, two diagnostic pathways using FFRct are compared to current clinical routine combining coronary computed tomography angiography (CCTA) with an exercise test. Model data are drawn from the literature and nationally reported data. Outcomes are assessed as the number of avoided invasive coronary angiographies (ICAs) showing no obstructive CAD and quality of life (QoL) in a theoretical cohort of 1000 patients. Sensitivity analyses are performed to test the robustness of the results. Determining FFRct when CCTA is inconclusive is a cost-effective and dominant strategy with a potential saving of 198€/patient, 154 avoided unnecessary ICA showing no obstructive CAD (uICA)/1000 patients and an average improvement in QoL of 0.008 QALY/patient. With an additional 574€/patient, 8 avoided uICA/1000 patients and an improvement in QoL of 0.001 QALY/patient, a strategy where FFRct is always performed is cost-effective only when considering high cost-effectiveness thresholds.

CONCLUSIONS

For patients presenting to the ED with acute chest pain and a low to intermediate pre-test probability of CAD, a diagnostic strategy where FFRct is determined after an inconclusive CCTA is cost-effective. Clinical trials investigating both sensitivity and specificity of FFRct, as well as QoL associated with the use of this technology in this setting are warranted.

Impact of vessel morphology on CT-derived fractional-flow-reserve in non-obstructive coronary artery disease in right coronary artery

OBJECTIVES

Computed tomography (CT)-derived fractional flow reserve (FFRCT) decreases continuously from proximal to distal segments of the vessel due to the influence of various factors even in non-obstructive coronary artery disease (NOCAD). It is known that FFRCT is dependent on vessel-length, but the relationship with other vessel morphologies remains to be explained.

PURPOSE

To investigate morphological aspects of the vessels that influence FFRCT in NOCAD in the right coronary artery (RCA).

METHODS

A total of 443 patients who underwent both FFRCT and invasive coronary angiography, with < 50% RCA stenosis, were evaluated. Enrolled RCA vessels were classified into two groups according to distal FFRCT: FFRCT ≤ 0.80 (n = 60) and FFRCT > 0.80 (n = 383). Vessel morphology (vessel length, lumen diameter, lumen volume, and plaque volume) and left-ventricular mass were assessed. The ratio of lumen volume and vessel length was defined as V/L ratio.

RESULTS

Whereas vessel-length was almost the same between FFRCT ≤ 0.80 and > 0.80, lumen volume and V/L ratio were significantly lower in FFRCT ≤ 0.80. Distal FFRCT correlated with plaque-related parameters (low-attenuation plaque, intermediate-attenuation plaque, and calcified plaque) and vessel-related parameters (proximal and distal vessel diameter, vessel length, lumen volume, and V/L ratio). Among all vessel-related parameters, V/L ratio showed the highest correlation with distal FFRCT (r = 0.61, p < 0.0001). Multivariable analysis showed that calcified plaque volume was the strongest predictor of distal FFRCT, followed by V/L ratio (β-coefficient = 0.48, p = 0.03). V/L ratio was the strongest predictor of a distal FFRCT ≤ 0.80 (cut-off 8.1 mm3/mm, AUC 0.88, sensitivity 90.0%, specificity 76.7%, 95% CI 0.84-0.93, p < 0.0001).

CONCLUSIONS

Our study suggests that V/L ratio can be a measure to predict subclinical coronary perfusion disturbance.

CLINICAL RELEVANCE STATEMENT

A novel marker of the ratio of lumen volume to vessel length (V/L ratio) is the strongest predictor of a distal CT-derived fractional flow reserve (FFRCT) and may have the potential to improve the diagnostic accuracy of FFRCT.

KEY POINTS

• Physiological FFRCT decline depends not only on vessel length but also on the lumen volume in non-obstructive coronary artery disease in the right coronary artery. • FFRCT correlates with plaque-related parameters (low-attenuation plaque, intermediate-attenuation plaque, and calcified plaque) and vessel-related parameters (proximal and distal vessel diameter, vessel length, lumen volume, and V/L ratio). • Of vessel-related parameters, V/L ratio is the strongest predictor of a distal FFRCT and an optimal cut-off value of 8.1 mm3/mm.

Normalization of FFRCT after surgical unroofing of a myocardial bridge: a case report

Background

Cardiac computed tomography angiography derived fractional flow reserve (FFRCT) is a diastolic measurement and has emerged as a valuable non-invasive alternative to FFR in patients with stable coronary artery disease. It has, unlike FFR during coronary angiography, not been validated for the physiological evaluation of an isolated myocardial bridge (MB) so far.

Case summary

Our patient, previously known with a long myocardial bridge of the mid-segment of the left anterior descending artery, presented with a non-ST-segment elevation myocardial infarction that was treated by surgical unroofing of the MB. FFRCT after surgery confirms a major amelioration of coronary blood flow.

Discussion

Myocardial bridge may rarely present as a non-ST-segment elevation myocardial infarction. FFRCT has thus far been accepted as a useful diagnostic tool in stable coronary artery disease. Our case report suggests that cardiac computed tomography angiography may be considered a useful technique for anatomical and physiological evaluation of MBs.

Clinical and prognostic incremental value of FFRCT in screening of patients with obstructive coronary artery disease

BACKGROUND

Coronary computed tomography angiography (CCTA) -derived fractional flow reserve (FFRCT) is recommended to evaluate the functional consequences of obstructive coronary artery disease (OCAD). Real-world incremental impacts of FFRCT use still remains under debate.

METHODS

1601 patients with suspected OCAD on CCTA (>50 ​% stenosis), including 808 (50.5 ​%) patients evaluated by FFRCT, were included from a 2013-2021 registry. Propensity adjusted impacts of FFRCT use on rates of invasive coronary angiography (ICA), myocardial revascularization (MR) and post MR major adverse cardiac events (MACE) were reported, including a sensitivity analysis in severe OCAD (>70 ​% stenosis) (n ​= ​450). Accuracy of numerical and comprehensive FFRCT interpretations in selection of patients requiring a MR were also compared.

RESULTS

1160 (72,5 ​%) ICA, 559 (34.9 ​%) MR and 137 (24.5 ​%) post MR MACE occurred at 4.7 ​± ​1.9 years. FFRCT use was independently associated with decreased rate of ICA and MR (OR: 0.66; 95 ​% CI 0.53-0.83, p ​< ​0.001 and OR: 0.71; 95 ​% CI 0.58-0.88, p ​< ​0.01, respectively). Compared to the numerical interpretation, the FFRCT comprehensive assessment increased the ratio of MR per ICA (61.7 ​% vs 50.1 ​%, p ​< ​0.01) and was more accurate in selection of patients requiring MR. FFRCT reduced post MR MACE (OR: 0.64; 95 ​% CI 0.43-0.96, p ​< ​0.05). All these associations were no longer observed in severe OCAD.

CONCLUSION

Implementing FFRCT in OCAD patients reduces ICA use, improves selection of patients requiring MR and reduces post MR MACE. However, these incremental values of FFRCT were no longer observed in severe OCAD.

[Effects of air pollution on cardiovascular events in cardiac intensive care units]

Many environmental factors influence the occurrence of cardiovascular events. Among these, air pollution is certainly the most harmful, due to its dual composition and effects. Air pollution is both particulate and gaseous, and can vary in concentration and composition according to its source and type of emission. Moreover, clinical effects are not only observed at long-term but also at short-term, following rapid deterioration in air quality. Air pollution must therefore be seen both as a risk factor for atherosclerotic disease, and as a trigger for cardiovascular events. These acute effects are essentially mediated by an increased risk of acute coronary syndromes and heart failure. The effects of air pollution on admissions for ventricular arrhythmias and arterial hypertension are also possible. The cardiotoxicity of pollution is mainly mediated by sympatho-vagal imbalance, by the initiation and amplification of an oxidative, inflammatory and pro-aggregatory cascade, and by endothelial dysfunction and activation of metalloproteinases. Although now well established, the consequences of air pollution on acute cardiovascular events require further investigation. Environmental cardiology is an emerging discipline whose current vision still fails to integrate qualitative aspects, such as the oxidative potential of particulate matter, and the joint effects of multiple environmental exposures.

Depression and Malnutrition for Prediction of Mortality after Transcatheter Aortic Valve Replacement: A Registry Study of a Tertiary Referral Hospital

Moderate to severe frailty is a predictor of a poor outcome after transcatheter aortic valve replacement (TAVR), but little is known about the prognostic importance of different geriatric frailty markers in an overall fit or pre-frail geriatric population undergoing TAVR. This retrospective study aimed to examine the incremental value of adding patient frailty markers to conventional surgical risk score to predict all-cause mortality in relatively fit elderly patients undergoing TAVR. Overall patient frailty was assessed using the comprehensive geriatric assessment frailty index (CGA-FI). Multivariable Cox regression models were used to evaluate relationships of different geriatric frailty markers with all-cause mortality and single and combined frailty models were compared to a baseline model that included EuroSCORE II factors. One hundred relatively fit geriatric patients (84 ± 4 years old, mean CGA-FI 0.14 ± 0.05) were included, and 28% died during a median follow-up of 24 months. After adjustment, risk of depression (geriatric depression scale 15 (GDS-15)) and malnutrition remained significantly associated with all-cause mortality (HR 4.381, 95% CI 1.787-10.743; p = 0.001 and HR 3.076, 95% CI 1.151-8.217; p = 0.025, respectively). A combined frailty marker model including both GDS-15 and malnutrition on top of EuroSCORE II improved the discriminative ability to predict all-cause mortality (change in c-index: + 0.044). Screening for those frailty markers on top of the traditionally used EuroSCORE II may improve risk stratification and prognosis in relatively fit geriatric patients undergoing TAVR.

The impact of iodine contrast agent on radiation dose of heart and blood: a comparison between coronary CT angiography and cardiac calcium scoring CT

BACKGROUND

Iodine contrast agent (CA) is widely used in cardiac computed tomography (CT). The CA can increase the organ radiation doses due to the photoelectric effect.

PURPOSE

To investigate the impact of CA on radiation dose in cardiac CT by comparing the radiation dose between contrast coronary CT angiography (CCTA) and non-contrast calcium scoring CT (CSCT).

MATERIAL AND METHODS

Radiation doses were computationally calculated for 30 individual patients who received CSCT and CCTA in the same exam session. The geometry and acquisition parameters were modeled in the simulations based on individual patient CT images and acquisitions. Doses in the presence and absence of CA were obtained in the aorta, left ventricle (LV), right ventricle (RV), and myocardial tissue (MT). The dose values were normalized by size-specific dose estimate (SSDE). The dose enhancement factors (DEFSSDE) were calculated as the ratio of doses in CCTA over doses in CSCT.

RESULTS

Compared to the CSCT scans, doses increase in the CCTA scans in the aorta (DEFSSDE = 2.14 ± 0.20), LV (DEFSSDE = 1.78 ± 0.26), and RV (DEFSSDE = 1.31 ± 0.22). A linear relation is observed between the local CA concentrations and the dose increase in the heart; DEFSSDE = 0.07*I(mg/mL) + 0.80 (R2 = 0.8; p < 0.01). The DEFSSDE in the MT (DEFSSDE = 0.96 ± 0.08) showed no noticeable impact of CA on the dose in this tissue. In addition, patient variability in the dose distributions was observed.

CONCLUSION

A linear causal relation exists between local CA concentration and increase in radiation dose in cardiac CT. For the same CT exposure, dose to the heart is on average 55% higher in contrast cardiac CT.

Diagnostic performance of exercise stress tests for detection of epicardial and microvascular coronary artery disease: the UZ Clear study

BACKGROUND

Cardiac stress tests remain the cornerstone for evaluating patients suspected of having obstructive coronary artery disease (CAD). Coronary microvascular dysfunction (CMD) can lead to abnormal non-invasive tests.

AIMS

We sought to assess the diagnostic performance of exercise stress tests with indexes of epicardial and microvascular resistance as reference.

METHODS

This was a prospective, single-arm, multicentre study of patients with an intermediate pretest probability of CAD and positive exercise stress tests who were referred for invasive angiography. Patients underwent an invasive diagnostic procedure (IDP) with measurement of fractional flow reserve (FFR) and index of microvascular resistance (IMR) in at least one coronary vessel. Obstructive CAD was defined as diameter stenosis (DS) >50% by quantitative coronary angiography (QCA). The objective was to determine the false discovery rate (FDR) of cardiac exercise stress tests with both FFR and IMR as references.

RESULTS

One hundred and seven patients (137 vessels) were studied. The mean age was 62.1±8.7, and 27.1% were female. The mean diameter stenosis was 37.2±27.5%, FFR was 0.84±0.10, coronary flow reserve was 2.74±2.07, and IMR 20.3±11.9. Obstructive CAD was present in 39.3%, whereas CMD was detected in 20.6%. The FDR was 60.7% and 62.6% with QCA and FFR as references (p-value=0.803). The combination of FFR and IMR as clinical reference reduced the FDR by 25% compared to QCA (45.8% vs 60.7%; p-value=0.006).

CONCLUSIONS

In patients with evidence of ischaemia, an invasive functional assessment accounting for the epicardial and microvascular compartments led to an improvement in the diagnostic performance of exercise tests, driven by a significant FDR reduction.

Impact of ramus coronary artery on computed tomography derived fractional flow reserve (FFRCT ) in no apparent coronary artery disease

BACKGROUND

The ramus artery contributes to the development of turbulence, which may influence computed tomography (CT) derived fractional flow reserve (FFR_CT ) even without coronary artery disease (CAD). The relationship between ramus-induced turbulence and FFR_CT is unclear.

METHOD AND RESULTS

A total of 120 patients with <20% coronary stenosis assessed by both FFR_CT and invasive coronary angiography were evaluated. The patients were divided into three groups: absent-ramus (n = 72), small-ramus that could not be analyzed by FFR_CT (n = 18), and large-ramus that could be analyzed by FFR_CT (n = 30). FFR_CT measurements were performed at the proximal and distal segments of the left anterior descending (LAD), left circumflex (LCX), and ramus artery. With absent-ramus and small-absent ramus groups, FFR_CT was measured at the distal end of the left main trunk at the same level for the proximal segments of the LAD and LCX. In absent-ramus group, proximal FFR_CT showed no significant differences between three vessels (LAD = .96 ± .02; MID = .97 ± .02; LCX = .97 ± .02). However, in small and large-ramus groups, proximal FFR_CT was significantly higher in the ramus artery than LAD and LCX (small-ramus, LAD = .95 ± .03, Ramus = .97 ± .02, LCX = .95 ± .03; large-ramus: LAD = .95 ± .03, Ramus = .98 ± .01; LCX = .96 ± .03; p < .05). A large ramus was associated with a higher prevalence of a distal FFR_CT ≤.80 (odds ratio 7.0, 95% CI 1.2-40.1, p = .03). A proximal ramus diameter predicted distal FFR_CT ≤.80 (cut-off 2.1 mm, AUC .76, sensitivity 100%, specificity 52%, 95% CI .61-.90).

CONCLUSIONS

The presence of a large-ramus artery may cause an FFR_CT decline in no apparent CAD.

Evaluation of coronary artery disease in patients undergoing atrial fibrillation ablation: a non-invasive FFR computed tomography study

To evaluate coronary artery disease (CAD) with computed tomography coronary angiography (CTCA)-derived fractional flow reserve (FFR) in patients with atrial fibrillation (AF) requiring ablation. The study population consisted of 151 patients who underwent CTCA before AF ablation (AF group), and a control group of 151 patients from the outpatient clinic who underwent CTCA without any history of AF (non-AF group), matched for age, sex, BMI, and angina symptomatology. All study patients underwent CTCA with subdivision of coronary lesion type into severe (≥ 70% luminal narrowing), moderate (50% ≤ luminal narrowing < 70%), and mild stenosis (< 50% luminal narrowing). In patients with ≥ 1 moderate or severe stenosis, non-invasive FFR was calculated from CTCA (FFR_CT). Baseline characteristics and CAD risk factors were similar between the 2 groups. During CTCA, 38% of the patients in the AF group were in ongoing atrial arrhythmia (either AF or regular atrial tachycardia). The number of patients with severe (10 (6.6%) vs 10 (6.6%), P = 1.00), moderate (14 (9.5%) vs 10 (6.7%), P = 0.4), and mild stenosis (43 (28.5%) vs 56 (37.1%), P = 0.11) was not significantly different between the 2 groups. Performance of FFR_CT was feasible in 32/44 patients (73%), and failed in 27% of the patients (7 and 5 patients in the AF and non-AF group, respectively, P = 0.74). No difference was observed in the prevalence of hemodynamically significant stenosis (FFR_CT ≤ 0.80) (15 (9.9%) vs 12 (7.9%), P = 0.85). Our study showed technical feasibility of CTCA in all patients of both groups, including the patients with AF as presenting rhythm. The FFR_CT add-on analysis failed equally frequent in patients of the AF versus non-AF group. An equal rate of CAD was observed in the AF group and non-AF group, favoring the concept of shared associated risk factors for CAD and AF.

Impact of coronary bifurcation angle on computed tomography derived fractional flow reserve in coronary vessels with no apparent coronary artery disease

OBJECTIVES

Computed tomography (CT) derived fractional flow reserve (FFR_CT) decreases from the proximal to the distal part due to a variety of factors. The energy loss due to the bifurcation angle may potentially contribute to a progressive decline in FFR_CT. However, the association of the bifurcation angle with FFR_CT is still not entirely understood. This study aimed to investigate the impact of various bifurcation angles on FFR_CT decline below the clinically crucial relevance of 0.80 in vessels with no apparent coronary artery disease (CAD).

METHODS

A total of 83 patients who underwent both CT angiography including FFR_CT and invasive coronary angiography, exhibiting no apparent CAD were evaluated. ΔFFR_CT was defined as the change in FFR_CT from the proximal to the distal in the left anterior descending artery (LAD) and left circumflex artery (LCX). The bifurcation angle was calculated from three-dimensional volume rendered images. Vessel morphology and plaque characteristics were also assessed.

RESULTS

ΔFFR_CT significantly correlated with the bifurcation angle (LAD angle, r = 0.35, p = 0.001; LCX angle, r = 0.26, p = 0.02) and vessel length (LAD angle, r = 0.30, p = 0.005; LCX angle, r = 0.49, p < 0.0001). In LAD, vessel length was the strongest predictor for distal FFR_CT of ≤ 0.80 (β-coefficient = 0.55, p = 0.0003), immediately followed by the bifurcation angle (β-coefficient = 0.24, p = 0.02). The bifurcation angle was a good predictor for a distal FFR_CT ≤ 0.80 (LAD angle, cut-off 31.0°, AUC 0.70, sensitivity 74%, specificity 68%; LCX angle, cut-off 52.6°, AUC 0.86, sensitivity 88%, specificity 85%).

CONCLUSIONS

In vessels with no apparent CAD, vessel length was the most influential factor on FFR_CT, directly followed by the bifurcation angle.

KEY POINTS

• Both LAD and LCX bifurcation angles are factors influencing FFR _CT. • Bifurcation angle is one of the predictors of a distal FFR_CT of ≤ 0.80 and an optimal cut-off value of 31.0° for the LAD and 52.6° for the LCX. • Bifurcation angle should be taken into consideration when interpreting numerical values of FFR_CT.

Impact of vessel morphology on computed tomography derived fractional flow reserve (FFRCT) in normal coronary artery disease: a novel marker for the predictor of FFRCT changes

Background

Computed tomography (CT) derived fractional flow reserve (FFRCT) decreases continuously from the proximal to the distal segments of the vessel even in normal coronary arteries. It has been empirically proved that the degree of FFRCT decline varies based on vessel morphology even in the same vessel length.

Purpose

To investigate the vessel morphological factors that influence FFRCT in normal coronary arteries.

Methods

A total of 1402 outpatients with suspected CAD who underwent CT angiography (CTA) with FFRCT analysis between January 2017 and October 2021 were evaluated. Among them, 234 consecutive patients who underwent both CT angiography including FFRCT and invasive coronary angiography, resulting in &lt;20% stenosis in right coronary artery (RCA) were evaluated. RCA vessels from ostium to just proximal site of the posterior descending branch were analysed and divided into two groups according to distal FFRCT: FFRCT &gt;0.80 (n=219) and FFRCT ≤0.80 (n=15). FFRCT was measured at proximal and distal segments of the RCA. Vessel morphology (vessel length, lumen diameter and volume, and plaque volume) and left ventricular mass were assessed. The ratio of lumen volume and vessel length was defined as the V/L ratio.

Results

Whereas vessel length was almost the same between FFRCT &gt;0.80 and ≤0.80 (&gt;0.80 vs. ≤0.80, 115.9±17.3 vs. 119.6±28.7 mm), lumen volume (1135.2±369.3 vs. 906.2±362.6 mm3, p&lt;0.05) and V/L ratio (9.8±2.6 vs. 7.5±2.3, p&lt;0.01) were significantly higher in FFRCT &gt;0.80. Distal FFRCT correlated with plaque-related parameters [low-attenuation plaque, intermediate-attenuation plaque, and calcified plaque (CP)] and vessel-related parameters (proximal and distal vessel diameter, vessel length, lumen volume, and V/L ratio). Among all vessel-related parameters, V/L ratio showed the highest correlation with distal FFRCT (r=0.44, p&lt;0.0001) (Figure 1). Multivariable analysis showed that CP volume was the strongest predictor of distal FFRCT (β-coefficient = −0.38, p&lt;0.0001), followed by V/L ratio (β-coefficient = 0.95, p=0.007). V/L ratio was the strongest predictor of a distal FFRCT ≤0.80 (cut-off 8.2, AUC 0.73, sensitivity 66.7%, specificity 69.3%, 95% CI 0.60–0.86) (Figure 2).

Conclusions

Our study findings suggest that the V/L ratio can be a measure to predict subclinical coronary perfusion disturbance.

Funding Acknowledgement

Type of funding sources: None.

Impact of vascular morphology and plaque characteristics on computed tomography derived fractional flow reserve in early stage coronary artery disease

BACKGROUND

Computed-tomography (CT) derived fractional-flow-reserve (FFR_CT) gradually may decrease from proximal to distal vessels even without apparent coronary artery disease (CAD). It may be unclear whether the decrease in FFR_CT at the distal coronal artery is physiological or due to stenosis. We decided to study predictive factors of an FFR_CT decline below the pathological value of 0.80 in no-apparent CAD.

METHODS

A total of 150 consecutive patients who had both CT angiography coupled to FFR_CT analysis and invasive angiogram showing < 20% coronary stenosis were included. Vessels were divided into two groups according to FFR_CT at the distal vessel: FFR_CT > 0.80 (n = 317) and FFR_CT ≤ 0.80 (n = 114). ΔFFR_CT was defined as the change in FFR_CT from proximal to distal vessel. Vessel morphology (vessel length and lumen volume) and plaque characteristics [low-attenuation plaque volume, intermediate-attenuation (IAP) plaque volume, and calcified plaque volume] were evaluated.

RESULTS

FFR_CT decreased from proximal to distal for the three major vessels in both FFR_CT > 0.80 and FFR_CT ≤ 0.80. Compared to FFR_CT > 0.80, IAP volume was significantly higher in all three major vessels in FFR_CT ≤ 0.80. ΔFFR_CT was correlated with vessel length and lumen volume in FFR_CT > 0.80, whereas ΔFFR_CT was correlated with IAP volume in FFR_CT ≤ 0.80. IAP volume above 44.8 mm³ was the strongest predictor of distal FFR_CT of ≤ 0.80.

CONCLUSIONS

The presence of IAP is a major predictor of gradual decrease of FFR_CT below 0.80 in no-apparent CAD vessels. Vessel morphology and plaque characteristics should be considered when interpreting FFR_CT.

Adherence to quality indicators for ST-elevation myocardial infarction and its relation to mortality: a hospital network analysis from the Belgian STEMI database

AIMS

To assess the adherence to established quality indicators (QIs) for ST-elevation myocardial infarction (STEMI) at the hospital-network level and its relation to outcome.

METHODS AND RESULTS

The data of 7774 STEMI patients admitted to 32 STEMI networks during the period 2014-18 were extracted from the Belgian STEMI database. Five QIs [primary percutaneous coronary intervention use, diagnosis-to-balloon time (DiaTB) <90 min, door-to-balloon time (DoTB) <60 min, P2Y12 inhibitor and statin prescription at discharge, and a composite QI score ranging from 0 to 10] were correlated with in-hospital mortality adjusted for differences in baseline risk profile (TIMI risk score). The median composite QI score was 6.5 [interquartile range (IQR) 6-8]. The most important gaps in quality adherence were related to time delays: the recommended DiaTB and DoTB times across the different networks were achieved in 68% (IQR 53-71) and 67% (IQR 50-78), respectively. Quality adherence was better in networks taking care of more high-risk STEMI patients. The median in-hospital mortality among the STEMI networks was 6.4% (IQR 4.1-7.9%). There was a significant independent inverse correlation between the composite QI score and in-hospital mortality (partial correlation coefficient: -0.45, P = 0.013). Stepwise regression analysis revealed that among the individual QIs, prolonged DiaTB was the most important independent outcome predictor.

CONCLUSION

Among established STEMI networks, the time delay between diagnosis and treatment was the most variable and the most relevant prognostic QI, underscoring the importance of assessing quality of care throughout the whole network.

Effects of left ventricular mass index on computed tomography derived fractional flow reserve in significant obstructive coronary artery disease

Background

In significant obstructive coronary artery disease (SOCAD), a mismatched assessment of the severity of coronary artery stenosis may occur between invasive coronary angiography and computed tomography (CT) derived fractional flow reserve (FFRCT). The exact mechanisms of unexpected underestimation of FFRCT remain unknown.

Purpose

The aims of this study are (1) to clarify the mechanisms of underestimation on FFRCT; and (2) to identify the predictive factors of FFRCT underestimation above the value of 0.80 in SOCAD vessels.

Methods

A total of 1160 outpatients who underwent CT angiography (CTA) with FFRCT analysis for suspected coronary artery disease (CAD) between January 2017 and June 2020 were evaluated. Among them, 141 consecutive patients who had both CTA coupled to FFRCT analysis and invasive angiogram showing &gt;75% coronary stenosis were included for analysis. Vessels were divided into two groups according to FFRCT at the distal vessel: FFRCT &gt;0.80 (n=12) and FFRCT ≤0.80 (n=153). Vessel-related parameters, including vessel morphology (vessel length and lumen volume) and plaque components (non-calcified plaque volume and calcified plaque volume) and left ventricular (LV) myocardial-related parameters, including LV wall thickness at each site of the myocardium, and LV mass were evaluated semi-automatically.

Results

Vessel morphology and plaque components did not differ between FFRCT &gt;0.80 and ≤0.80, whereas LV wall thickness (average; 10.7±2.7 vs. 8.4±1.6 mm, and maximal; 13.5±3.0 vs. 10.6±1.8 mm, all p value &lt;0.001), LV mass (136.4±38.4 vs. 98.8±26.8 g, p&lt;0.001), and LV mass index (73.8±22.6 vs. 51.8±12.2 g/m2, p&lt;0.001) were significantly higher in FFRCT &gt;0.80. Next, we investigated the parameters that correlated with FFRCT. Of all, vessel morphology and plaque components were not related to FFRCT, whereas maximal LV wall thickness, r=0.24, p=0.01; LV mass, r=0.19. p=0.04; and LV mass index, r=0.30, p=0.001) correlated with FFRCT. In the vessels showing FFRCT &gt;0.80, only LV mass (r=0.84, p=0.005) and LV mass index (r=0.67, p=0.047) correlated with FFRCT. (Figure 1). LV mass index was the strongest predictor of a distal FFRCT of &gt;0.80 with the area under curve (AUC) 0.81, 95% CI 0.62 – 1.00, P&lt;0.0001 and an optimal cut-off value of 66.5 g/m2 sensitivity 77.8%, specificity 89.6% (Figure 2).

Conclusions

FFRCT is affected not by vessel-related parameters but LV myocardial-related parameters in SOCAD. The presence of an excessive LV mass is a major predictor of underestimation of FFRCT in SOCAD vessels. LV myocardial-related parameters should be considered when interpreting numerical values of FFRCT to avoid the possibility of overlooked SOCAD.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Impact of vascular morphology and plaque characteristics on computed tomography derived fractional flow reserve in early stage coronary artery disease

Background

FFRCT gradually decreases from the proximal to the distal part of a vessel and reach the pathological threshold for significant ischemia even in the absence of obstructive coronary artery disease (CAD). The exact mechanisms of such gradual FFRCT decline remain unknown.

Purpose

The aims of this study are (1) to clarify the mechanisms of the gradual decline of computed tomography (CT) derived fractional flow reserve (FFRCT); and (2) to identify the predictive factors of an FFRCT decline below the pathological value of 0.80 in no apparent CAD vessels.

Methods

A total of 1058 outpatients with suspected CAD and who underwent CT angiography (CTA) with FFRCT analysis between January 2017 and December 2019 were evaluated. Among them, 150 consecutive patients who had both a CTA coupled to an FFRCT analysis and an invasive angiogram showing &lt;25% coronary stenosis were included for analysis. Vessels were divided into two groups according to FFRCT at the distal vessel: FFRCT &gt;0.80 (n=317) and FFRCT ≤0.80 (n=114). ΔFFRCT was defined as the magnitude of the change in FFRCT from the proximal to the distal vessel. Plaque characterization and vessel morphology measurements were performed semi-automatically. Vessel constituents were characterized based on Hounsfield units (HU) into lumen volume (&lt;−50 HU), non-calcified plaque (NCP) (−50–150 HU), and calcified plaque (&gt;150 HU).

Results

FFRCT decreased continuously from the proximal to distal across the three major vessels in both FFRCT&gt;0.80 and FFRCT ≤0.80 groups (Figure 1). Compared to FFRCT&gt;0.80 group, NCP volume was significantly higher in all three major vessels in FFRCT ≤0.80 group (210.2±83.6 mm3 vs. 140.9±139.3 mm3 for the RCA, p=0.01; 177.5±150.2 mm3 vs. 133.2±112.2 mm3 for the LAD, p=0.04; 127.6±91.5 mm3 vs. 58.7±57.7 mm3 for the LCX, p&lt;0.01). Next, we investigated the vessel parameters that correlated with ΔFFRCT. ΔFFRCT was correlated with lumen volume in FFRCT&gt;0.80 group (r=−0.24, p&lt;0.0001), whereas ΔFFRCT was correlated with NCP volume in FFRCT ≤0.80 group (r=0.42, p&lt;0.001) (Figure 2). An NCP volume above 44.8 mm3 was the strongest predictor of distal FFRCT of ≤0.80 (area under the curve 0.69, p&lt;0.0001, sensitivity 95%, specificity 39%).

Conclusions

FFRCT is affected by vascular morphology and plaque characteristics even in the early stage of coronary artery disease. Our study highlights that subclinical coronary artery disease strongly influences FFRCT by effects unrelated to coronary stenosis. The presence of NCP is a major predictor of the gradual decrease of FFRCT toward pathological values. Anatomical findings as vessel morphology and plaque characteristics should be taken into consideration when interpreting numerical values of FFRCT to avoid unnecessary referrals for invasive coronary angiography or percutaneous coronary intervention.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Impact of COVID-19-related public containment measures on the ST elevation myocardial infarction epidemic in Belgium: a nationwide, serial, cross-sectional study

AIMS

The current study assessed the impact of COVID-19-related public containment measures (i.e. lockdown) on the ST elevation myocardial infarction (STEMI) epidemic in Belgium.

METHODS AND RESULTS

Clinical characteristics, reperfusion therapy modalities, COVID-19 status and in-hospital mortality of consecutive STEMI patients who were admitted to Belgian hospitals for percutaneous coronary intervention (PCI) were recorded during a three-week period starting at the beginning of the lockdown period on 13 March 2020. Similar data were collected for the same time period for 2017-2019. An evaluation of air quality revealed a 32% decrease in ambient NO₂ concentrations during lockdown (19.5 µg/m³ versus 13.2 µg/m³, p < .001). During the three-week period, there were 188 STEMI patients admitted for PCI during the lockdown versus an average 254 STEMI patients before the lockdown period (incidence rate ratio = 0.74, p = .001). Reperfusion strategy was predominantly primary PCI in both time periods (96% versus 95%). However, there was a significant delay in treatment during the lockdown period, with more late presentations (>12 h after onset of pain) (14% versus 7.6%, p = .04) and with longer door-to-balloon times (median of 45 versus 39 min, p = .02). Although the in-hospital mortality between the two periods was comparable (5.9% versus 6.7%), 5 of the 7 (71%) COVID-19-positive STEMI patients died.

CONCLUSION

The present study revealed a 26% reduction in STEMI admissions and a delay in treatment of STEMI patients. Less exposure to external STEMI triggers (such as ambient air pollution) and/or reluctance to seek medical care are possible explanations of this observation.

Guiding Myocardial Revascularization by Algorithmic Interpretation of FFR Pullback Curves: A Proof of Concept Study

Background: Coronary artery disease distribution along the vessel is a main determinant of FFR improvement after PCI. Identifying focal from diffuse disease from visual inspections of coronary angiogram (CA) and FFR pullback (FFR-PB) are operator-dependent. Computer science may standardize interpretations of such curves. Methods: A virtual stenting algorithm (VSA) was developed to perform an automated FFR-PB curve analysis. A survey analysis of the evaluations of 39 vessels with intermediate disease on CA and a distal FFR <0.8, rated by 5 interventional cardiologists, was performed. Vessel disease distribution and PCI strategy were successively rated based on CA and distal FFR (CA); CA and FFR-PB curve (CA/FFR-PB); and CA and VSA (CA/VSA). Inter-rater reliability was assessed using Fleiss kappa and an agreement analysis of CA/VSA rating with both algorithmic and human evaluation (operator) was performed. We hypothesize that VSA would increase rater agreement in interpretation of epicardial disease distribution and subsequent evaluation of PCI eligibility. Results: Inter-rater reliability in vessel disease assessment by CA, CA/FFR-PB, and CA/VSA were respectively, 0.32 (95% CI: 0.17-0.47), 0.38 (95% CI: 0.23-0.53), and 0.4 (95% CI: 0.25-0.55). The raters' overall agreement in vessel disease distribution and PCI eligibility was higher with the VSA than with the operator (respectively, 67 vs. 42%, and 80 vs. 70%, both p < 0.05). Compared to CA/FFR-PB, CA/VSA induced more reclassification toward a focal disease (92 vs. 56.2%, p < 0.01) with a trend toward more reclassification as eligible for PCI (70.6 vs. 33%, p = 0.06). Change in PCI strategy did not differ between CA/FFR-PB and CA/VSA (23.6 vs. 28.5%, p = 0.38). Conclusions: VSA is a new program to facilitate and standardize the FFR pullback curves analysis. When expert reviewers integrate VSA data, their assessments are less variable which might help to standardize PCI eligibility and strategy evaluations. Clinical Trial Registration: https://www.clinicaltrials.gov/ct2/show/NCT03824600.

P854Physiological patterns of coronary artery disease

Background

Randomised controlled trials have confirmed the clinical benefit of invasive functional assessment to guide clinical decision making about myocardial revascularisation in patients with stable coronary artery disease. Treatment decision is based on one FFR value which provides a vessel-level metric as a surrogate of myocardial ischaemia. Also, the distribution of epicardial conductance can be evaluated using an FFR pullback manoeuvre.

Purpose

The objective of the present study is to characterise the physiological patterns of CAD using motorised coronary pressure pullbacks during continuous hyperaemia in patients with stable coronary artery disease.

Methods

Prospective, multicentre study of patients undergoing clinically-indicated coronary angiography. A pullback device, adapted to grip the coronary pressure wire, was set at a speed of 1 mm/sec. The pattern of CAD was adjudicated by visual inspection of the FFR pullback curves as focal, diffuse, or a combination of both mechanisms. Also, a quantitative classification of the physiological pattern of CAD was performed based on (1) the functional contribution of the epicardial lesion in relation to the total vessel FFR (Δlesion FFR/Δvessel FFR) and (2) the length (mm) of epicardial coronary segments with FFR drops in relation to the total vessel length. The combination of these two ratios, namely, lesion-related pressure drops (%FFR-lesion), and the extent of functional disease, resulted in the functional outcomes index (FOI), a metric that represents the pattern of CAD (i.e. focality or diffuseness) based on coronary physiology. Agreement on CAD patterns and between observers was assessed using Fleiss' Kappa. Analysis of variance (ANOVA) was used to compared quantitative variables. Correlation between variables was assessed by the Pearson moment coefficient.

Results

One hundred and fifty-eight vessels were included; 984,813 FFR values were used to generate the FFR pullback curves. Using motorised FFR pullbacks, 34% of the vessel disease patterns (i.e. focal, diffuse or combined) were reclassified compared to conventional angiography. The mean contribution of the angiographic lesions to the distal FFR (%FFR-lesion) was 61.7±25% whereas vessel length with the physiological disease was 59.8±21% of the total vessel length. The mean FOI was 0.61±0.17, and differentiated focal from diffuse CAD in terms of %FFR-lesion (p<0.001) and physiological extent of CAD (p<0.001).

Conclusion

Coronary angiography was inaccurate to assess the patterns of CAD. The inclusion of the functional component reclassified 34% of the vessel disease patterns (i.e. focal, diffuse or combined). A new metric, the FOI, based on the functional impact of anatomical lesions and the extent of physiological disease, discriminated focal from diffuse CAD. Further clinical trials are required to evaluate the usefulness of FOI for clinical decision making and outcomes.

P809Effects of air temperature and pollution on Takotsubo cardiomyopathy

Background

Air temperature and pollution are the main environmental factors influencing cardiovascular mortality and risk of myocardial infarction. Takotsubo cardiomyopathy (TCM) is a transient and reversible myocardial dysfunction whose cause and pathogenesis remain incompletely understood, but which, unlike acute coronary syndrome, does not involve obstructive coronary atherosclerosis or plaque rupture. The potential role of the environment on the risk to develop TCM remains poorly defined.

Methods

We aimed to study the effects of air temperature, particulate matter (PM) and gaseous pollutants (NO2 and ozone) on hospitalization rate forTCM.

All hospitalizations in Belgian Hospitals for TCM (ICD 9:429.83) from 2009 to 2014 were recorded. National air pollution parameters were extracted from the Belgian Environment Agency database. A time-stratified and temperature-matched (except for air temperature effect) case-crossover analysis of the risk of TCM was performed. The main analysis focused on 0-day lag time (lag 0) between exposure and TCM; a lag structure analysis up to lag 4 was also performed.

Results

1840 patients were included in the study (88% women). More TCM occurred during the warm compared to the cold period (fig.1; chi2p value <0.05). At lag 0, each decrease of 1°C in ambient air temperature increased the odds ratio (OR) of TCM of 1.020 (IC 95%: 1.003–1.035). This effect was more pronounced during the cold period and at lag 4 (RR 1.060; IC 95%: 1.031–1.091). Conversely, during the warm period and between lag 1 and 4, an increase of 1°C in ambient air temperature increased the RR of TCM (OR 1.053 at lag 3; IC 95%: 1.021–1.086). No significant association was found between TCM and PM10, PM2.5, NO2at any lag. During the warm period, each increase in 10μg/m3 in ozone from lag 1 to 3 increased the risk of TCM (OR 1.089 at lag 3, IC 95%: 1.017–1.168).

Conclusions

Air temperature strongly influences the onset of TCM. Both cold spells and heat waves seem to be associated with the development of TCM. Ozone exposure also increases the risk of TCM during the warm period, whereas particulate and NO2 pollution do not seem to play a significant role. These patterns seem to differ from those previously reported with STEMI.

P855Evaluation of epicardial coronary resistance using computed tomography angiography

Background

A Fractional flow reserve (FFR) pullback allows assessing the distribution of pressure loss along the vessel. FFR derived from CT (FFRCT) provides a virtual pullback curve that may also aid in the assessment of epicardial coronary resistance in the non-invasive setting.

Purpose

The present study aims to determine the accuracy of the virtual FFRCT pullback curve using a motorized invasive FFR pullback as reference in patients with stable coronary artery disease.

Methods

This is a single centre, prospective study of patients with stable coronary artery disease in whom FFRCT was performed as standard of care for non-invasive assessment. Patients referred to coronary angiography with clinically indicated invasive FFR measurement were included. FFRCT and invasive FFR values were extracted from coronary vessels every 1 mm to generate pullback curves. Invasive FFR pullbacks were acquired using a dedicated device at a speed of 1 mm/s. The area under the pullback curve (AUPC), defined as the sum of areas under the FFR pullback curve, was compared between FFRCT and invasive FFR pullbacks. Lesions were defined based on invasive angiography. FFR gradients in lesions and non-obstructive segments were defined as the difference between FFR values at the proximal and distal edge of the segments. FFR vessel gradient was defined as the difference between the most distal FFR value and the FFR at the ostium of the vessel. Mixed effect model was used to account for the correlation of FFR values within vessels. The agreement between FFRCT and FFR gradients was assessed using the Passing Bablok regression analysis and Bland-Altman methods at the vessel, lesion and non-obstructive level.

Results

A total of 3172 matched FFRCT and FFR values were obtained in 24 vessels. The correlation coefficient between FFRCT and FFR was 0.76 (95% CI 0.75 to 0.78; p<0.001). The mean difference between the FFRCT and invasive FFR pullback values was 0.07 (LOA −0.11 to 0.24). AUPC was similar between FFRCT and invasive FFR (79.0±16.1 vs. 85.3±16.4, p=0.097); the mean slope of FFRCT pullback curve was steeper compared to invasive FFR (p<0.001). The mean difference in lesion gradient was −0.07 (LOA −0.26 to 0.13) and −0.01 (LOA −0.06 to 0.05) in non-obstructive segments. There were no systematic or proportional differences between FFRCT and FFR gradients either in lesion or non-obstructive segments); however, vessel gradients were overestimated by FFRCT with a bias of −0.12 (LOA −0.35 to 0.12) driven by a higher mean difference in lesion gradients (−0.07; 95% CI −0.26 to 0.13).

Conclusions

The evaluation of epicardial coronary resistance using coronary CT angiography with FFRCT was feasible. FFRCT pullbacks were accurate in the assessment of lesion and non-obstructive gradients. FFRCT can identify the physiological pattern of coronary artery disease in the non-invasive setting.

Ecology of the cardiovascular system: Part II - A focus on non-air related pollutants

An integrated exposomic view of the relation between environment and cardiovascular health should consider the effects of both air and non-air related environmental stressors. Cardiovascular impacts of ambient air temperature, indoor and outdoor air pollution were recently reviewed. We aim, in this second part, to address the cardiovascular effects of noise, food pollutants, radiation, and some other emerging environmental factors. Road traffic noise exposure is associated with increased risk of premature arteriosclerosis, coronary artery disease, and stroke. Numerous studies report an increased prevalence of hypertension in people exposed to noise, especially while sleeping. Sleep disturbances generated by nocturnal noise are followed by a neuroendocrine stress response. Some oxidative and inflammatory endothelial reactions are observed during experimental session of noise exposure. Moreover, throughout the alimentation, the cardiovascular system is exposed to persistent organic pollutants (POPs) as dioxins or pesticides, and plastic associated chemicals (PACs), such as bisphenol A. Epidemiological studies show positive associations of exposures to POPs and PACs with diabetes, arteriosclerosis and cardiovascular disease incidence. POPs and PACS share some abilities to interact with nuclear receptors activating different pathways leading to oxidative stress, insulin resistance and angiotensin potentiation. Regarding radiation, survivors of nuclear explosion have an excess risk of cardiovascular disease. Dose-effect relationships remain debated, but an increased cardiovascular risk at low dose of radiation exposure may be of concern. Some emerging environmental factors like electromagnetic fields, greenspace and light exposure may also require further attention. Non-air related environmental stressors also play an important role in the burden of cardiovascular disease. Specific methodologies should be developed to assess the interactions between air and non-air related pollutants.

Pro-thrombotic effect of exercise in a polluted environment: a P-selectin- and CD63-related platelet activation effect

Exposure to diesel exhaust is an important cardiovascular risk factor and may promote atherothrombotic events. Some data suggest that polluted air exposure could affect haemostasis through platelet activation. The aim of the study was to investigate the effects of acute exposure to diesel exhaust on platelet activation and platelet function. We tested the hypothesis in a randomised, crossover study in 25 healthy men exposed to ambient and polluted air; 11 of the subjects also performed exercise during exposure sessions. Platelet activation was evaluated by surface expression of CD62P (P-selectin) and CD63 (dense granule glycoprotein) using flow cytometry of labelled platelets. Platelet function was measured using the PFA-100 platelet function analyser and by Multiplate whole blood impedance platelet aggregometry. Acute diesel exhaust exposure had no effect on platelet activation at rest, but exercise in polluted air increased the collagen- induced expression of CD62P and CD63 (both p< 0.05). The increase in the expression of CD62P and CD63 was related to the total amount of PM2.5 inhaled during the exercise sessions (r=+0.58 and +0.60, respectively, both p< 0.05). Platelet aggregation was not impaired after polluted air exposure at rest or during exercise. In conclusion, in healthy subjects, diesel exhaust exposure induces platelet activation as illustrated by a dose-response increase in the release of CD62P and CD63. This platelet priming effect could be a contributor to the triggering of atherothrombotic events related to air pollution exposure.

Cardiovascular effects of air pollution

Air pollution is composed of particulate matter (PM) and gaseous pollutants, such as nitrogen dioxide and ozone. PM is classified according to size into coarse particles (PM₁₀), fine particles (PM_2.5) and ultrafine particles. We aim to provide an original review of the scientific evidence from epidemiological and experimental studies examining the cardiovascular effects of outdoor air pollution. Pooled epidemiological studies reported that a 10μg/m³ increase in long-term exposure to PM_2.5 was associated with an 11% increase in cardiovascular mortality. Increased cardiovascular mortality was also related to long-term and short-term exposure to nitrogen dioxide. Exposure to air pollution and road traffic was associated with an increased risk of arteriosclerosis, as shown by premature aortic and coronary calcification. Short-term increases in air pollution were associated with an increased risk of myocardial infarction, stroke and acute heart failure. The risk was increased even when pollutant concentrations were below European standards. Reinforcing the evidence from epidemiological studies, numerous experimental studies demonstrated that air pollution promotes a systemic vascular oxidative stress reaction. Radical oxygen species induce endothelial dysfunction, monocyte activation and some proatherogenic changes in lipoproteins, which initiate plaque formation. Furthermore, air pollution favours thrombus formation, because of an increase in coagulation factors and platelet activation. Experimental studies also indicate that some pollutants have more harmful cardiovascular effects, such as combustion-derived PM_2.5 and ultrafine particles. Air pollution is a major contributor to cardiovascular diseases. Promotion of safer air quality appears to be a new challenge in cardiovascular disease prevention.

Effects of HeartWare ventricular assist device on the von Willebrand factor: results of an academic Belgian center

Background

Left Ventricular Assist Device (LVAD) is a promising therapy for patients with advanced heart failure (HF), but bleeding complications remain an important issue. Previous series show that acquired von Willebrand syndrome was present in up to 100 % of first generation LVAD recipients. We report the effects of new generation LVADs on vW factor (vWF) metabolism and activity in our center.

Methods

Fifteen LVAD recipients (HeartWare®, Framingham, MA, USA) were compared to 12 HF patients, matched for age and body mass index. vWF antigen and activity, as well as D-dimers, were measured on hemostasis analyzers. A vWF LVAD-induced alteration was evocated when the [vWF activity]/[vWF antigen] ratio was <0.6. ADAMTS13 and high molecular weight multimers of vWF were also assessed.

Results

LVAD recipients had similar levels of endothelial vWF production than the HF subjects (137 ± 14.5 vs. 147 ± 11.7 %; respectively, p = 0.611) but a decreased vWF activity (90 ± 11 vs. 132.6 ± 13 %; respectively, p = 0.017). [vWF activity]/[vWF antigen] ratio was 0.65 ± 0.02 in the LVAD recipients and 0.92 ± 0.06 in the subjects with HF (p = 0.001). ADAMTS13 activity was 80.3 ± 4.7 % in LVAD recipients and 96.2 ± 3.5 % in the HF patients (p = 0.016). LVAD patients disclosed markedly elevated D-dimers (3217.7 ± 735 vs. 680.6 ± 223.2 ng/mL FEU in the HF patients, p = 0.006). The LVAD patients experienced one major hemorrhagic event and one systemic thrombotic event during the median follow-up of 345 days.

Conclusions

LVAD recipients achieved a new hemostatic equilibrium characterized by infrequent major hemorrhagic and thrombotic events, despite a mildly impaired vWF function and a markedly enhanced thrombin formation.

Trial registration

ISRCTN39517567

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0334-z) contains supplementary material, which is available to authorized users.

Air pollution and ST-elevation myocardial infarction: A case-crossover study of the Belgian STEMI registry 2009-2013

BACKGROUND

Previous studies have shown that air pollution particulate matter (PM) is associated with an increased risk for myocardial infarction. The effects of air pollution on the risk of ST-elevation myocardial infarction (STEMI), in particular the role of gaseous air pollutants such as NO₂ and O₃ and the susceptibility of specific populations, are still under debate.

METHODS

All patients entered in the Belgian prospective STEMI registry between 2009 and 2013 were included. Based on a validated spatial interpolation model from the Belgian Environment Agency, a national index was used to address the background level of air pollution exposure of Belgian population. A time-stratified and temperature-matched case-crossover analysis of the risk of STEMI was performed.

RESULTS

A total of 11,428 STEMI patients were included in the study. Each 10μg/m³ increase in PM10, PM2.5 and NO₂ was associated with an increased odds ratio (ORs) of STEMI of 1.026 (CI _95%: 1.005-1.048), 1.028 (CI _95%: 1.003-1.054) and 1.051 (CI _95%: 1.018-1.084), respectively. No effect of O₃ was found. STEMI was associated with PM10 exposure in patients ≥75y.o. (OR: 1.046, CI _95%: 1.002-1.092) and with NO₂ in patients ≤54y.o. (OR: 1.071, CI _95%: 1.010-1.136). No effect of air pollution on cardiac arrest or in-hospital STEMI mortality was found.

CONCLUSION

PM2.5 and NO₂ exposures incrementally increase the risk of STEMI. The risk related to PM appears to be greater in the elderly, while younger patients appear to be more susceptible to NO₂ exposure.

At high cardiac output, diesel exhaust exposure increases pulmonary vascular resistance and decreases distensibility of pulmonary resistive vessels

Air pollution has recently been associated with the development of acute decompensated heart failure, but the underlying biological mechanisms remain unclear. A pulmonary vasoconstrictor effect of air pollution, combined with its systemic effects, may precipitate decompensated heart failure. The aim of the present study was to investigate the effects of acute exposure to diesel exhaust (DE) on pulmonary vascular resistance (PVR) under resting and stress conditions but also to determine whether air pollution may potentiate acquired pulmonary hypertension. Eighteen healthy male volunteers were exposed to ambient air (AA) or dilute DE with a particulate matter of <2.5 μm concentration of 300 μg/m(3) for 2 h in a randomized, crossover study design. The effects of DE on PVR, on the coefficient of distensibilty of pulmonary vessels (α), and on right and left ventricular function were evaluated at rest (n = 18), during dobutamine stress echocardiography (n = 10), and during exercise stress echocardiography performed in hypoxia (n = 8). Serum endothelin-1 and fractional exhaled nitric oxide were also measured. At rest, exposure to DE did not affect PVR. During dobutamine stress, the slope of the mean pulmonary artery pressure-cardiac output relationship increased from 2.8 ± 0.5 mmHg · min · l (-1) in AA to 3.9 ± 0.5 mmHg · min · l (-1) in DE (P < 0.05) and the α coefficient decreased from 0.96 ± 0.15 to 0.64 ± 0.12%/mmHg (P < 0.01). DE did not further enhance the hypoxia-related upper shift of the mean pulmonary artery pressure-cardiac output relationship. Exposure to DE did not affect serum endothelin-1 concentration or fractional exhaled nitric oxide. In conclusion, acute exposure to DE increased pulmonary vasomotor tone by decreasing the distensibility of pulmonary resistive vessels at high cardiac output.

[Many possible causes of variant angina]

BACKGROUND

Variant angina, or vasospastic angina, is a form of angina caused by vasospasm of the coronary arteries, probably caused by endothelial dysfunction. This form of angina is provoked by non-classical risk factors such as stress, alcohol use, use of sympathomimetics and low environmental temperatures, but also by smoking. Treatment is based on elimination of risk factors and vasodilator therapy with nitrates and long-acting calcium antagonists.

CASE DESCRIPTION

We present a 68-year-old woman with recurring thoracalgia at rest and during exercise, suggestive of severe variant angina in more than one coronary artery. Despite elimination of risk factors and administration of vasodilatory therapy the treatment was initially insufficient. It eventually emerged that the probable cause was frequent use of a vasoconstrictive nasal spray, although this was not described in literature, and not originally mentioned by the patient.

CONCLUSION

A thorough case history is of vital importance in a patient presenting with a history suggestive of variant angina. Even undescribed and apparently less important risk factors can be responsible for persistence of symptoms, and can lead to an applied treatment not producing the desired result.

Quantification of low-gradient severe aortic stenosis using a hybrid approach combining Doppler echocardiography and thermodilution

BACKGROUND AND AIM OF THE STUDY

Estimation of stroke volume in the left ventricular outflow tract (LVOT) is a main limitation to aortic valve area (AVA) calculation by echocardiography when using the continuity equation. In this study, the hypothesis was tested that a hybrid method using thermodilution-derived cardiac output measurement and simultaneous Doppler estimation of the systolic ejection period and transvalvular aortic velocities could be used to accurately assess AVA in patients with low-gradient severe aortic stenosis (AS).

METHODS

Eighteen patients with low mean gradient (< 40 mmHg) and nine patients with conventionally defined (> or = 40 mmHg) severe AS (< 1 cm2), as assessed by the echocardiographic continuity equation (baseline echocardiography), underwent catheterization and simultaneous Doppler recording of trans-aortic velocities.

RESULTS

The mean pressure gradient was slightly lower by Doppler in the catheterization laboratory (35.8 +/-15.7 mmHg) compared to baseline echocardiography (37.4 +/- 15.2 mmHg) and invasive (38.5 +/- 16.6 mmHg) measurements (both p < 0.05). The AVA values were 0.72 +/- 0.12 cm2 during baseline echocardiography, 0.74 +/- 0.14 cm2 by catheterization, and 0.71 +/- 0.14 cm2 by the hybrid method (bias -0.01 +/- 0.11 cm2 and -0.02 +/- 0.08 cm2, versus echocardiography and catheterization, respectively; both p = NS).

CONCLUSION

The hybrid method is reasonably accurate in assessing AVA in patients with low-gradient severe AS. Although the continuity equation should be used in routine clinical practice in most patients, this method could serve as an alternative when the LVOT diameter and/or velocities seem questionable.

Looking at the frame after the picture: "retrocardiac echocardiography"

We report three cases of mediastinal structures encroaching on the left atrium without haemodynamic compromise. These cases emphasize the potential role of echocardiography for the diagnosis and the management of several extracardiac mediastinal abnormalities.

Acute exposure to diesel exhaust impairs nitric oxide-mediated endothelial vasomotor function by increasing endothelial oxidative stress

Exposure to diesel exhaust was recently identified as an important cardiovascular risk factor, but whether it impairs nitric oxide (NO)-mediated endothelial function and increases production of reactive oxygen species (ROS) in endothelial cells is not known. We tested these hypotheses in a randomized, controlled, crossover study in healthy male volunteers exposed to ambient and polluted air (n=12). The effects of skin microvascular hyperemic provocative tests, including local heating and iontophoresis of acetylcholine and sodium nitroprusside, were assessed using a laser Doppler imager. Before local heating, skin was pretreated by iontophoresis of either a specific NO-synthase inhibitor (L-N-arginine-methyl-ester) or a saline solution (Control). ROS production was measured by chemiluminescence using the lucigenin technique in human umbilical vein endothelial cells preincubated with serum from 5 of the subjects. Exposure to diesel exhaust reduced acetylcholine-induced vasodilation (P<0.01) but did not affect vasodilation with sodium nitroprusside. Moreover, the acetylcholine/sodium nitroprusside vasodilation ratio decreased from 1.51 ± 0.1 to 1.06 ± 0.07 (P<0.01) and was correlated to inhaled particulate matter 2.5 (r=-0.55; P<0.01). NO-mediated skin thermal vasodilatation decreased from 466 ± 264% to 29 ± 123% (P<0.05). ROS production was increased after polluted air exposure (P<0.01) and was correlated with the total amount of inhaled particulate matter <2.5 μm (PM2.5). In healthy subjects, acute experimental exposure to diesel exhaust impaired NO-mediated endothelial vasomotor function and promoted ROS generation in endothelial cells. Increased PM2.5 inhalation enhances microvascular dysfunction and ROS production.

[Renal denervation: new treatment for refractory hypertension?]

Sympathetic renal hyperactivity is involved hypertension and in its progression towards organ damages. Using femoral access, a dedicated ablation catheter can be inserted into the renal vessels to deliver high frequency energy in the arterial wall. This therapy leads to a focal heating, which ablates the renal nerve fibers running in the adventitia. First clinical results (Simplicity HTN 1 and HTN 2 trials) have demonstrated a significant and sustained decrease in office blood pressure. The response rate to this therapy was about 85 to 90%. This procedure did not cause serious adverse event and seems to have also positive impact on glucose metabolism and exercise capacity. Based on these first results, renal denervation appears as a new interesting therapy, which requires further studies to better define its place in the antihypertensive therapeutic arsenal. Actually, it should not be considered as an alternative to pharmacological therapy and renal denervation should be only proposed to patients with resistant hypertension. Prior to renal denervation, an upstream work has to be done to ensure an adequate patient selection. The mandatory point is to ensure that patient scheduled for this therapy respond to the definition of arterial resistant hypertension. Because of the narrowed limit between the very common situation of "uncontrolled" hypertension and the "true resistant" group, we proposed a 3 steps algorithm that can help for patient selection.

Acute effects of nicotine on arterial stiffness and wave reflection in healthy young non-smokers

1. Recently, we have demonstrated that cigarette smoke exposure proportionally increases plasma nicotine levels and arterial wave reflection to the aorta. However, the exact contribution of nicotine to the smoke-induced enhancement of wave reflection and the potential underlying mechanisms have not been fully investigated. 2. The present study was a prospective study in 15 healthy male non-smokers. All received a placebo and a 2 mg nicotine tablet, according to a randomized double-blind cross-over study design. Each subject underwent repeated measurements at baseline and for 1 h after nicotine or placebo intake, using carotid-femoral pulse wave velocity (PWV) to assess arterial compliance. Concurrently, aortic pressures and the augmentation index were evaluated using applanation tonometry. 3. Plasma nicotine concentrations achieved 1 h after intake of the nicotine tablet reached comparable levels to those achieved after 1 h exposure to passive smoke (3.6 +/- 0.4 vs 3.2 +/- 0.4 ng/mL, respectively; P = 0.4). 4. Nicotine enhanced arterial wave reflection to the aorta, as assessed by the augmentation index corrected for heart rate (4.2 +/- 1.3 vs-0.7 +/- 0.8% with placebo; P = 0.001). In addition, a progressive increase in carotid-femoral PWV was noted after nicotine administration (0.3 +/- 0.1 vs-0.02 +/- 0.1 m/s with placebo; P = 0.04). This remained significant even after adjustment for changes in mean blood pressure and heart rate (P = 0.01). 5. Plasma nicotine concentrations comparable to those achieved after exposure to passive smoke enhance arterial wave reflection to the aorta. This is accompanied by an increase in carotid-femoral PWV, denoting a deterioration of arterial compliance by nicotine.

Facial cooling and peripheral chemoreflex mechanisms in humans

AIM

Reductions in arterial oxygen partial pressure activate the peripheral chemoreceptors which increase ventilation, and, after cessation of breathing, reduce heart rate. We tested the hypothesis that facial cooling facilitates these peripheral chemoreflex mechanisms.

METHODS

Chemoreflex control was assessed by the ventilatory response to hypoxia (10% O2 in N2) and the bradycardic response to voluntary end-expiratory apnoeas of maximal duration in 12 young, healthy subjects. We recorded minute ventilation, haemoglobin O2 saturation, RR interval (the time between two R waves of the QRS complex) and the standard deviation of the RR interval (SDNN), a marker of cardiac vagal activity throughout the study. Measurements were performed with the subject's face exposed to air flow at 23 and 4 degrees C.

RESULTS

Cold air decreased facial temperature by 11 degrees C (P < 0.0001) but did not affect minute ventilation during normoxia. However, facial cooling increased the ventilatory response to hypoxia (P < 0.05). The RR interval increased by 31 +/- 8% of the mean RR preceding the apnoea during the hypoxic apnoeas in the presence of cold air, compared to 17 +/- 5% of the mean RR preceding the apnoea in the absence of facial cooling (P < 0.05). This increase occurred despite identical apnoea durations and reductions in oxygen saturation. Finally, facial cooling increased SDNN during normoxia and hypoxia, as well as during the apnoeas performed in hypoxic conditions (all P < 0.05).

CONCLUSION

The larger ventilatory response to hypoxia suggests that facial cooling facilitates peripheral chemoreflex mechanisms in normal humans. Moreover, simultaneous diving reflex and peripheral chemoreflex activation enhances cardiac vagal activation, and favours further bradycardia upon cessation of breathing.

Acute effect of sidestream cigarette smoke extract on vascular endothelial function

Acute exposure to passive smoking adversely affects vascular function by promoting oxidative stress and endothelial dysfunction. However, it is not known whether tobacco sidestream (SS) smoke has a greater deleterious effect on the endothelium than non-tobacco SS smoke and whether these effects are related to nicotinic endothelial stimulation. To test these hypotheses, endothelial-dependent relaxation and superoxide anion production were assessed in isolated rat aortas incubated with tobacco SS smoke, non-tobacco SS smoke, or pure nicotine. Tobacco SS smoke decreased the maximal relaxation to acetylcholine (Ach) from 79 +/- 6% to 57 +/- 7.3% (% inhibition of phenylephrine-induced plateau, P < 0.001) and increased superoxide anion production from 31 +/- 9.7 to 116 +/- 24 count/10 sec/mg (P < 0.01, lucigenin-enhanced chemiluminescence technique). The non-tobacco SS smoke extract had no significant effect on the response to Ach but increased superoxide anion production in the aortic wall to 133 +/- 2 count/10 sec/mg (P < 0.001). Furthermore, concentration-response curves to Ach and superoxide production remained unaltered with nicotine (0.001, 0.01, or 0.1 mM). In conclusion, despite similar increases in vascular wall superoxide production with tobacco and non-tobacco SS smoke, only the tobacco SS smoke extracts affected endothelium-dependent vasorelaxation. Nicotine alone does not reproduce the effects seen with tobacco SS smoke, suggesting that the acute endothelial toxicity of passive smoking cannot simply be ascribed to a nicotine-dependent mechanism.

Effects of enoximone on peripheral and central chemoreflex responses in humans

cAMP plays an important role in peripheral chemoreflex function in animals. We tested the hypothesis that the phosphodiesterase inhibitor and inotropic medication enoximone increases peripheral chemoreflex function in humans. In a single-blind, randomized, placebo-controlled crossover study of 15 men, we measured ventilatory, muscle sympathetic nerve activity, and hemodynamic responses to 5 min of isocapnic hypoxia, 5 min of hyperoxic hypercapnia, and 3 min of isometric handgrip exercise, separated by 1 wk, with enoximone and placebo administration. Enoximone increased cardiac output by 120 ± 3.7% from baseline ( P < 0.001); it also increased the ventilatory response to acute hypoxia [13.6 ± 1 vs. 11.2 ± 0.7 l/min at 5 min of hypoxia, P = 0.03 vs. placebo (by ANOVA)]. Despite a larger minute ventilation and a smaller decrease in O2 desaturation (83 ± 1 vs. 79 ± 2%, P = 0.003), the muscle sympathetic nerve response to hypoxia was similar between enoximone and placebo (123 ± 6 and 117 ± 6%, respectively, P = 0.28). In multivariate regression analyses, enoximone enhanced the ventilatory ( P < 0.001) and sympathetic responses to isocapnic hypoxia. Hyperoxic hypercapnia and isometric handgrip responses were not different between enoximone and placebo ( P = 0.13). Enoximone increases modestly the chemoreflex responses to isocapnic hypoxia. Moreover, this effect is specific for the peripheral chemoreflex, inasmuch as central chemoreflex and isometric handgrip responses were not altered by enoximone.

Differential effects of metaboreceptor and chemoreceptor activation on sympathetic and cardiac baroreflex control following exercise in hypoxia in human

Muscle metaboreceptors and peripheral chemoreceptors exert differential effects on the cardiorespiratory and autonomic responses following hypoxic exercise. Whether these effects are accompanied by specific changes in sympathetic and cardiac baroreflex control is not known. Sympathetic and cardiac baroreflex functions were assessed by intravenous nitroprusside and phenylephrine boluses in 15 young male subjects. Recordings were performed in random order, under locally circulatory arrested conditions, during: (1) rest and normoxia (no metaboreflex and no chemoreflex activation); (2) normoxic post-handgrip exercise at 30% of maximum voluntary contraction (metaboreflex activation without chemoreflex activation); (3) hypoxia without handgrip (10% O2 in N2, chemoreflex activation without metaboreflex activation); and (4) post-handgrip exercise in hypoxia (chemoreflex and metaboreflex activation). When compared with normoxic rest (-42 +/- 7% muscle sympathetic nerve activity (MSNA) mmHg(-1)), sympathetic baroreflex sensitivity did not change during normoxic post-exercise ischaemia (PEI; -53 +/- 9% MSNA mmHg(-1), P = 0.5) and increased during resting hypoxia (-68 +/- 5% MSNA mmHg(-1), P < 0.01). Sympathetic baroreflex sensitivity decreased during PEI in hypoxia (-35 +/- 6% MSNA mmHg(-1), P < 0.001 versus hypoxia without exercise; P = 0.16 versus normoxic PEI). Conversely, when compared with normoxic rest (11.1 +/- 1.7 ms mmHg(-1)), cardiac baroreflex sensitivity did not change during normoxic PEI (8.3 +/- 1.3 ms mmHg(-1), P = 0.09), but decreased during resting hypoxia (7.3 +/- 0.8 ms mmHg(-1), P < 0.05). Cardiac baroreflex sensitivity was lowest during PEI in hypoxia (4.3 +/- 1 ms mmHg(-1), P < 0.01 versus hypoxia without exercise; P < 0.001 versus normoxic exercise). The metaboreceptors and chemoreceptors exert differential effects on sympathetic and cardiac baroreflex function. Metaboreceptor activation is the major determinant of sympathetic baroreflex sensitivity, when these receptors are stimulated in the presence of hypoxia.

Does Endothelin Play a Role in Chemoreception During Acute Hypoxia in Normal Men?

BACKGROUND

The peripheral chemoreceptors are the dominant reflex mechanism responsible for the rise in ventilation and muscle sympathetic nerve activity (MSNA) in response to hypoxia. Animal studies have suggested that endothelin (ET) plays an important role in chemosensitivity. Moreover, several human clinical conditions in which circulating ET levels are increased are accompanied by enhanced chemoreflex sensitivity. Whether ET plays a role in normal human chemosensitivity is unknown.

METHODS

We determined whether bosentan, a nonspecific ET receptor antagonist, would decrease chemoreflex sensitivity in 14 healthy subjects. We assessed the effects of bosentan on the response to isocapnic hypoxia, using a randomized, crossover, double-blinded study design.

RESULTS

Bosentan increased mean (+/- SEM) plasma ET levels from 1.97 +/- 0.28 to 2.53 +/- 0.23 pg/mL (p = 0.01). Hypoxia increased mean minute ventilation from 6.7 +/- 0.3 to 8+/0.4 L/min (p < 0.01), mean MSNA from 100 to 111 +/- 5% (p < 0.01), mean heart rate from 67 +/- 3 to 86 +/- 3 beats/min (p < 0.01), and mean systolic BP from 116 +/- 3 to 122 +/- 3 mm Hg (p < 0.01). However, none of these responses differed between therapy with bosentan and therapy with placebo (p = 0.26). Bosentan did not affect the mean MSNA responses to the apneas, during normoxia (change from baseline: placebo, 259 +/- 58%; bosentan, 201 +/- 28%; p = 0.17) or during hypoxia (change from baseline: placebo, 469 +/- 139%; bosentan, 329 +/- 46%; p = 0.24). The durations of the voluntary end-expiratory apneas in normoxia and hypoxia, and the subsequent reductions in oxygen saturation, were also similar with therapy using bosentan and placebo (p = 0.42).

CONCLUSION

In healthy men, ET does not play an important role in peripheral chemoreceptor activation by acute hypoxia.