Comparison of admittance and cardiac magnetic resonance generated pressure-volume loops in a porcine model

Objective. Pressure-volume loop analysis, traditionally performed by invasive pressure and volume measurements, is the optimal method for assessing ventricular function, while cardiac magnetic resonance (CMR) imaging is the gold standard for ventricular volume estimation. The aim of this study was to investigate the agreement between the assessment of end-systolic elastance (Ees) assessed with combined CMR and simultaneous pressure catheter measurements compared with admittance catheters in a porcine model.Approach. Seven healthy pigs underwent admittance-based pressure-volume loop evaluation followed by a second assessment with CMR during simultaneous pressure measurements.Main results. Admittance overestimated end-diastolic volume for both the left ventricle (LV) and the right ventricle (RV) compared with CMR. Further, there was an underestimation of RV end-systolic volume with admittance. For the RV, however, Ees was systematically higher when assessed with CMR plus simultaneous pressure measurements compared with admittance whereas there was no systematic difference in Ees but large differences between admittance and CMR-based methods for the LV.Significance. LV and RV Ees can be obtained from both admittance and CMR based techniques. There were discrepancies in volume estimates between admittance and CMR based methods, especially for the RV. RV Ees was higher when estimated by CMR with simultaneous pressure measurements compared with admittance.

First-in-human left atrial appendage closure using the WATCHMAN FLX Pro device: a case report

Background

Device-related thrombosis (DRT) is a known complication to left atrial appendage closure (LAAC). The surface of a LAAC device should ideally have antithrombotic properties. The novel WATCHMAN FLX Pro (WFP) incorporates a fluoropolymer-coated fabric membrane designed to increase thromboresistance and facilitate endothelialization. Such features could potentially allow for a minimal post-procedural antithrombotic regimen. Radiopaque platinum markers at the device shoulders and a large 40 mm device are other novel features of the WFP.

Case summary

A 75-year-old man with atrial fibrillation was referred for LAAC due to prior subdural haemorrhage during direct-acting anticoagulation treatment. He underwent the first-in-human WFP implantation as part of the WATCHMAN FLX Pro CT study (NCT05567172). Computed tomography (CT) was used for pre-planning, and the procedure was performed under local analgesia guided by intracardiac echocardiography from the left atrium (LA) without any complications. Post-procedural antithrombotic treatment consisted of acetylsalicylic acid 75 mg/day only, and 45-day CT, transoesophageal echocardiography (TEE), and magnetic resonance imaging demonstrated optimal device position with complete LAAC. Hypoattenuated thickening (6 mm) appeared on the device as a smooth surface in continuity with the left atrial wall on CT and TEE. A specific magnetic resonance T1-weighted scan, used for visualization of fresh thrombus, suggested this to represent tissue ingrowth rather than thrombus.

Discussion

The advanced follow-up imaging protocol suggested a good WFP implantation result with signs of tissue ingrowth at 45 days. The added radiopaque markers facilitated optimal deployment, evaluation of device stability during tug test, and assessment of device protrusion into the LA.

Increasing Levels of Positive End-expiratory Pressure Cause Stepwise Biventricular Stroke Work Reduction in a Porcine Model

BACKGROUND

Positive end-expiratory pressure (PEEP) is commonly applied to avoid atelectasis and improve oxygenation in patients during general anesthesia but affects cardiac pressures, volumes, and loading conditions through cardiorespiratory interactions. PEEP may therefore alter stroke work, which is the area enclosed by the pressure-volume loop and corresponds to the external work performed by the ventricles to eject blood. The low-pressure right ventricle may be even more susceptible to PEEP than the left ventricle. The authors hypothesized that increasing levels of PEEP would reduce stroke work in both ventricles.

METHODS

This was a prospective, observational, experimental study. Six healthy female pigs of approximately 60 kg were used. PEEP was stepwise increased from 0 to 5, 7, 9, 11, 13, 15, 17, and 20 cm H2O to cover the clinical spectrum of PEEP. Simultaneous, biventricular invasive pressure-volume loops, invasive blood pressures, and ventilator data were recorded.

RESULTS

Increasing PEEP resulted in stepwise reductions in left (5,740 ± 973 vs. 2,303 ± 1,154 mmHg · ml; P < 0.001) and right (2,064 ± 769 vs. 468 ± 133 mmHg · ml; P < 0.001) ventricular stroke work. The relative stroke work reduction was similar between the two ventricles. Left ventricular ejection fraction, afterload, and coupling were preserved. On the contrary, PEEP increased right ventricular afterload and caused right ventriculo-arterial uncoupling (0.74 ± 0.30 vs. 0.19 ± 0.13; P = 0.01) with right ventricular ejection fraction reduction (64 ± 8% vs. 37 ± 7%, P < 0.001).

CONCLUSIONS

A stepwise increase in PEEP caused stepwise reduction in biventricular stroke work. However, there are important interventricular differences in response to increased PEEP levels. PEEP increased right ventricular afterload leading to uncoupling and right ventricular ejection fraction decline. These findings may support clinical decision-making to further optimize PEEP as a means to balance between improving lung ventilation and preserving right ventricular function.

EDITOR’S PERSPECTIVE

Detection of brain lesions after catheter ablation depends on imaging criteria: insights from AXAFA-AFNET 5 trial

AIMS

Left atrial catheter ablation is well established in patients with symptomatic atrial fibrillation (AF) but associated with risk of embolism to the brain. The present analysis aims to assess the impact of diffusion-weighted imaging (DWI) slice thickness on the rate of magnetic resonance imaging (MRI)-detected ischaemic brain lesions after ablation.

METHODS AND RESULTS

AXAFA-AFNET 5 trial (NCT02227550) participants underwent MRI using high-resolution (hr) DWI (slice thickness: 2.5-3 mm) and standard DWI (slice thickness: 5-6 mm) within 3-48 h after ablation. In 321 patients with analysable brain MRI (mean age 64 years, 33% female, median CHA2DS2-VASc 2), hrDWI detected at least one acute brain lesion in 84 (26.2%) patients and standard DWI in 60 (18.7%; P < 0.01) patients. High-resolution diffusion-weighted imaging detected more lesions compared to standard DWI (165 vs. 104; P < 0.01). The degree of agreement for lesion confirmation using hrDWI vs. standard DWI was substantial (κ = 0769). Comparing the proportion of DWI-detected lesions, lesion distribution, and total lesion volume per patient, there was no difference in the cohort of participants undergoing MRI at 1.5 T (n = 52) vs. 3 T (n = 269).

CONCLUSION

The pre-specified AXAFA-AFNET 5 sub-analysis revealed significantly increased rates of MRI-detected acute brain lesions using hrDWI instead of standard DWI in AF patients undergoing ablation. In comparison to DWI slice thickness, MRI field strength had a no significant impact in the trial. Comparing the varying rates of ablation-related MRI-detected brain lesions across previous studies has to consider these technical parameters. Future studies should use hrDWI, as feasibility was demonstrated in the multicentre AXAFA-AFNET 5 trial.

Two Different Clinical Presentations and Stages of Loeffler Endocarditis Diagnosed by Multimodality Investigations

•Loeffler endocarditis is a rare condition with various etiologies. •Timely diagnosis of Loeffler endocarditis through multimodal imaging is essential. •Treatment response in Loeffler endocarditis varies by disease stage. •Prognosis in Loeffler endocarditis varies by disease stage.

Automated detection of cardiac rest period for trigger delay calculation for image-based navigator coronary magnetic resonance angiography

BACKGROUND

Coronary magnetic resonance angiography (coronary MRA) is increasingly being considered as a clinically viable method to investigate coronary artery disease (CAD). Accurate determination of the trigger delay to place the acquisition window within the quiescent part of the cardiac cycle is critical for coronary MRA in order to reduce cardiac motion. This is currently reliant on operator-led decision making, which can negatively affect consistency of scan acquisition. Recently developed deep learning (DL) derived software may overcome these issues by automation of cardiac rest period detection.

METHODS

Thirty individuals (female, n = 10) were investigated using a 0.9 mm isotropic image-navigator (iNAV)-based motion-corrected coronary MRA sequence. Each individual was scanned three times utilising different strategies for determination of the optimal trigger delay: (1) the DL software, (2) an experienced operator decision, and (3) a previously utilised formula for determining the trigger delay. Methodologies were compared using custom-made analysis software to assess visible coronary vessel length and coronary vessel sharpness for the entire vessel length and the first 4 cm of each vessel.

RESULTS

There was no difference in image quality between any of the methodologies for determination of the optimal trigger delay, as assessed by visible coronary vessel length, coronary vessel sharpness for each entire vessel and vessel sharpness for the first 4 cm of the left mainstem, left anterior descending or right coronary arteries. However, vessel length of the left circumflex was slightly greater using the formula method. The time taken to calculate the trigger delay was significantly lower for the DL-method as compared to the operator-led approach (106 ± 38.0 s vs 168 ± 39.2 s, p < 0.01, 95% CI of difference 25.5-98.1 s).

CONCLUSIONS

Deep learning-derived automated software can effectively and efficiently determine the optimal trigger delay for acquisition of coronary MRA and thus may simplify workflow and improve reproducibility.

Effect of remote ischaemic conditioning on left ventricular function in ST-segment elevation myocardial infarction patients: The CONDI-2 echocardiographic sub-study

Background

Remote ischaemic conditioning (RIC) applied to the arm by inflation and deflation of a pneumatic cuff has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (PPCI). However, the effect of RIC on left ventricular ejection fraction (LVEF) following infarct healing remains unknown.

Objective

To investigate whether RIC applied in the ambulance before PPCI can improve left ventricular (LV) function in STEMI patients 3 months following infarction.

Methods

Echocardiography was performed in a total of 694 patients from the CONDI-2 study a median of 112 days (IQR 63) after the initial admission. LVEF and LV end-diastolic and end-systolic volumes were calculated using the modified Simpsons biplane method of disks. LV global longitudinal strain (GLS) was estimated using 2-dimensional cine-loops with a frame rate > 55 frames/second, measured in the three standard apical views.

Results

There was no difference in the measured echocardiographic parameters in the RIC group as compared to the control group, including LV EF, LV GLS, tricuspid annular plane systolic excursion or left ventricular volumes. In the control group, 32% had an ejection fraction < 50% compared to 37% in the RIC group (p = 0.129).

Conclusion

In this largest to date randomized imaging study of RIC, RIC as an adjunct to PPCI was not associated with a change in echocardiographic measures of cardiac function compared to standard PPCI alone.

Correlation between Serum Erythropoietin and Cerebral Collateral Flow in Acute Ischemic Stroke Patient

BACKGROUND

Erythropoietin (EPO), which is associated with anemia, exerts neuroprotective effects in ischemic stroke. In cases of stenosis or narrowing of the main cerebral blood vessel, the prognosis is favorable if collateral blood circulation is well developed in acute stroke. Several studies have investigated the relationship between EPO administration and stroke outcomes. The present study investigated the correlation between serum EPO level and cerebral collateral circulation, which could result in favorable clinical outcomes.

METHODS

The study subjects were patients diagnosed with acute ischemic stroke who underwent initial brain magnetic resonance imaging between January 2020 and March 2022. Following brain computed tomography perfusion for collateral flow, serum EPO levels were measured. Collaterals were assessed according to the Mass system and divided into good collateral (GC) or poor collateral (PC) groups. Serum EPO levels were determined using a chemiluminescence immunoassay method. A correlation coefficient analysis was conducted to determine the correlation between serum EPO levels and GC. A receiver operating characteristic curve analysis determined the cutoff value of EPO for GC.

RESULTS

Serum EPO levels were significantly higher in the GC than that in the PC group (P<0.05). The cut-off level of serum EPO for a good outcome was 9.1 mIU/mL.

CONCLUSION

A high serum EPO (>9.1 mIU/mL) could be a marker of GC in patients with acute ischemic stroke that predicts good clinical outcomes.

[Not Available]

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is characterized by clinical evidence of myocardial infarction with normal or near-normal coronary arteries on angiography (less-than 50% stenosis). MINOCA is a group of heterogeneous diseases with different pathophysiologic mechanism which all can cause ischaemia. MINOCA is considered a "working diagnosis" after angiography until further evaluation regarding its underlying cause is made. The aim of this review is to assess the literature on clinical features, aetiology, diagnosis, treatment and prognosis of patients with MINOCA.

Clinical presentation and cardiac imaging findings in patient cases of perimyocarditis and pericarditis with a temporal association to SARS-CoV-2 vaccination

Aims

We aimed to investigate and present cases of perimyocarditis and pericarditis verified by cardiovascular resonance (CMR) imaging in patients with a strong temporal association to SARS-CoV-2 vaccination. We sought to describe the clinical presentation including coronary artery angiography, CMR, transthoracic echocardiography, blood samples, electrocardiography, and symptoms.

Methods

We included 10 patients admitted with chest pain shortly after vaccination for SARS-CoV-2, who were diagnosed with pericarditis or perimyocarditis by CMR. We reviewed the CMR, echocardiography, electrocardiography, blood samples, coronary artery angiography, vital signs and medical history. The updated Lake Louise Criteria were used to determine the diagnosis by CMR.

Results

Eight patients had perimyocarditis and two patients had pericarditis. The mean age was 22 ± 5 years (range 16 to 31 years), 90% were male. The median time from vaccination to hospital admission was 4 days (range 2 to 28 days). Admissions were seen after vaccination with three different SARS-CoV-2 vaccine manufacturers. Nine Patients had ST-elevation on the initial electrocardiography. Peak troponins varied from 357 to 23,547 ng/l, with a median of 4,304 ng/l. Two patients had an LVEF <50% on echocardiography and four patients had left ventricular global longitudinal strain values <18%. CMR revealed preserved left ventricular ejection fraction (LVEF), although one patient had decreased LVEF on CMR. The T1 and T2 mapping values were increased in all patients. Of the 8 patients with perimyocarditis, all patients had signs of myocardial injury in the lateral segments of the left ventricle.

Conclusions

This case series of 10 patients supports the emerging evidence of an association between vaccination for SARS-CoV-2 and perimyocarditis and pericarditis, especially in young males. The temporal association was seen after vaccines from three different manufacturers. Imaging data from echocardiography and CMR displayed normal to mildly impaired cardiac function, usually with a mild disease course.

Cardiac Performance and Cardiopulmonary Fitness After Infection With SARS-CoV-2

Aims

Persistent cardiac symptoms are an increasingly reported phenomenon following COVID-19. However, the underlying cause of cardiac symptoms is unknown. This study aimed to identify the underlying causes, if any, of these symptoms 1 year following acute COVID-19 infection.

Methods and Results

22 individuals with persistent cardiac symptoms were prospectively investigated using echocardiography, cardiovascular magnetic resonance (CMR), 6-min walking test, cardio-pulmonary exercise testing and electrocardiography. A median of 382 days (IQR 368, 442) passed between diagnosis of COVID-19 and investigation. As a cohort their echocardiography, CMR, 6-min walking test and exercise testing results were within the normal ranges. There were no differences in left ventricular ejection fraction (61.45 ± 6.59 %), global longitudinal strain (19.80 ± 3.12 %) or tricuspid annular plane systolic excursion (24.96 ± 5.55 mm) as measured by echocardiography compared to a healthy control group. VO2 max (2045.00 ± 658.40 ml/min), % expected VO2 max (114.80 ± 23.08 %) and 6-minute distance walked (608.90 ± 54.51 m) exceeded that expected for the patient cohort, whilst Troponin I (5.59 ± 6.59 ng/l) and Nt-proBNP (88.18 ± 54.27 ng/l) were normal.

Conclusion

Among a cohort of 22 patients with self-reported persistent cardiac symptoms, we identified no underlying cardiac disease or reduced cardiopulmonary fitness 1 year following COVID-19.

Effect of remote ischaemic conditioning on infarct size and remodelling in ST-segment elevation myocardial infarction patients: the CONDI-2/ERIC-PPCI CMR substudy

The effect of limb remote ischaemic conditioning (RIC) on myocardial infarct (MI) size and left ventricular ejection fraction (LVEF) was investigated in a pre-planned cardiovascular magnetic resonance (CMR) substudy of the CONDI-2/ERIC-PPCI trial. This single-blind multi-centre trial (7 sites in UK and Denmark) included 169 ST-segment elevation myocardial infarction (STEMI) patients who were already randomised to either control (n = 89) or limb RIC (n = 80) (4 × 5 min cycles of arm cuff inflations/deflations) prior to primary percutaneous coronary intervention. CMR was performed acutely and at 6 months. The primary endpoint was MI size on the 6 month CMR scan, expressed as median and interquartile range. In 110 patients with 6-month CMR data, limb RIC did not reduce MI size [RIC: 13.0 (5.1-17.1)% of LV mass; control: 11.1 (7.0-17.8)% of LV mass, P = 0.39], or LVEF, when compared to control. In 162 patients with acute CMR data, limb RIC had no effect on acute MI size, microvascular obstruction and LVEF when compared to control. In a subgroup of anterior STEMI patients, RIC was associated with lower incidence of microvascular obstruction and higher LVEF on the acute scan when compared with control, but this was not associated with an improvement in LVEF at 6 months. In summary, in this pre-planned CMR substudy of the CONDI-2/ERIC-PPCI trial, there was no evidence that limb RIC reduced MI size or improved LVEF at 6 months by CMR, findings which are consistent with the neutral effects of limb RIC on clinical outcomes reported in the main CONDI-2/ERIC-PPCI trial.

Coronary Magnetic Resonance Angiography in Chronic Coronary Syndromes

Cardiovascular disease is the leading cause of mortality worldwide, with atherosclerotic coronary artery disease (CAD) accounting for the majority of cases. X-ray coronary angiography and computed tomography coronary angiography (CCTA) are the imaging modalities of choice for the assessment of CAD. However, the use of ionising radiation and iodinated contrast agents remain drawbacks. There is therefore a clinical need for an alternative modality for the early identification and longitudinal monitoring of CAD without these associated drawbacks. Coronary magnetic resonance angiography (CMRA) could be a potential alternative for the detection and monitoring of coronary arterial stenosis, without exposing patients to ionising radiation or iodinated contrast agents. Further advantages include its versatility, excellent soft tissue characterisation and suitability for repeat imaging. Despite the early promise of CMRA, widespread clinical utilisation remains limited due to long and unpredictable scan times, onerous scan planning, lower spatial resolution, as well as motion related image quality degradation. The past decade has brought about a resurgence in CMRA technology, with significant leaps in image acceleration, respiratory and cardiac motion estimation and advanced motion corrected or motion-resolved image reconstruction. With the advent of artificial intelligence, great advances are also seen in deep learning-based motion estimation, undersampled and super-resolution reconstruction promising further improvements of CMRA. This has enabled high spatial resolution (1 mm isotropic), 3D whole heart CMRA in a clinically feasible and reliable acquisition time of under 10 min. Furthermore, latest super-resolution image reconstruction approaches which are currently under evaluation promise acquisitions as short as 1 min. In this review, we will explore the recent technological advances that are designed to bring CMRA closer to clinical reality.

Remodeling after myocardial infarction and effects of heart failure treatment investigated by hyperpolarized [1-13 C]pyruvate magnetic resonance spectroscopy

PURPOSE

Hyperpolarized [1-¹³ C]pyruvate MRS can measure cardiac metabolism in vivo. We investigated whether [1-¹³ C]pyruvate MRS could predict left ventricular remodeling following myocardial infarction (MI), long-term left ventricular effects of heart failure medication, and could identify responders to treatment.

METHODS

Thirty-five rats were scanned with hyperpolarized [1-¹³ C]pyruvate MRS 3 days after MI or sham surgery. The animals were re-examined after 30 days of therapy with β-blockers and ACE-inhibitors (active group, n = 12), placebo treatment (placebo group, n = 13) or no treatment (sham group, n = 10). Furthermore, heart tissue mitochondrial respiratory capacity was assessed by high-resolution respirometry. Metabolic results were compared between groups, over time and correlated to functional MR data at each time point.

RESULTS

At 30 ± 0.5 days post MI, left ventricular ejection fraction (LVEF) differed between groups (sham, 77% ± 1%; placebo, 52% ± 3%; active, 63% ± 2%, P < .001). Cardiac metabolism, measured by both hyperpolarized [1-¹³ C]pyruvate MRS and respirometry, neither differed between groups nor between baseline and follow-up. Three days post MI, low bicarbonate + CO₂ /pyruvate ratio was associated with low LVEF. At follow-up, in the active group, a poor recovery of LVEF was associated with high bicarbonate + CO₂ /pyruvate ratio, as measured by hyperpolarized MRS.

CONCLUSION

In a rat model of moderate heart failure, medical treatment improved function, but did not on average influence [1-¹³ C]pyruvate flux as measured by MRS; however, responders to heart failure medication had reduced capacity for carbohydrate metabolism.

Pulmonary vasodilation by sildenafil in acute intermediate-high risk pulmonary embolism: a randomized explorative trial

BACKGROUND

To investigate if acute pulmonary vasodilation by sildenafil improves right ventricular function in patients with acute intermediate-high risk pulmonary embolism (PE).

METHODS

Single center, explorative trial. Patients with PE were randomized to a single oral dose of sildenafil 50 mg (n = 10) or placebo (n = 10) as add-on to conventional therapy. The time from hospital admission to study inclusion was 2.3 ± 0.7 days. Right ventricular function was evaluated immediately before and shortly after (0.5-1.5 h) randomization by right heart catheterization (RHC), trans-thoracic echocardiography (TTE), and cardiac magnetic resonance (CMR). The primary efficacy endpoint was cardiac index measured by CMR.

RESULTS

Patients had acute intermediate-high risk PE verified by computed tomography pulmonary angiography, systolic blood pressure of 135 ± 18 (mean ± SD) mmHg, increased right ventricular/left ventricular ratio 1.1 ± 0.09 and increased troponin T 167 ± 144 ng/L. Sildenafil treatment did not improve cardiac index compared to baseline (0.02 ± 0.36 l/min/m2, p = 0.89) and neither did placebo (0.00 ± 0.34 l/min/m2, p = 0.97). Sildenafil lowered mean arterial blood pressure (- 19 ± 10 mmHg, p < 0.001) which was not observed in the placebo group (0 ± 9 mmHg, p = 0.97).

CONCLUSION

A single oral dose of sildenafil 50 mg did not improve cardiac index but lowered systemic blood pressure in patients with acute intermediate-high risk PE. The time from PE to intervention, a small patient sample size and low pulmonary vascular resistance are limitations of this study that should be considered when interpreting the results.

TRIAL REGISTRATION

The trial was retrospectively registered at www.clinicaltrials.gov (NCT04283240) February 2nd 2020, https://clinicaltrials.gov/ct2/show/NCT04283240?term=NCT04283240&draw=2&rank=1 .

Veno-occlusive unloading of the heart reduces infarct size in experimental ischemia-reperfusion

Mechanical unloading of the left ventricle reduces infarct size after acute myocardial infarction by reducing cardiac work. Left ventricular veno-occlusive unloading reduces cardiac work and may reduce ischemia and reperfusion injury. In a porcine model of myocardial ischemia-reperfusion injury we randomized 18 pigs to either control or veno-occlusive unloading using a balloon engaged from the femoral vein into the inferior caval vein and inflated at onset of ischemia. Evans blue and 2,3,5-triphenyltetrazolium chloride were used to determine the myocardial area at risk and infarct size, respectively. Pressure-volume loops were recorded to calculate cardiac work, left ventricular (LV) volumes and ejection fraction. Veno-occlusive unloading reduced infarct size compared with controls (Unloading 13.9 ± 8.2% versus Control 22.4 ± 6.6%; p = 0.04). Unloading increased myocardial salvage (54.8 ± 23.4% vs 28.5 ± 14.0%; p = 0.02), while the area at risk was similar (28.4 ± 6.7% vs 27.4 ± 5.8%; p = 0.74). LV ejection fraction was preserved in the unloaded group, while the control group showed a reduced LV ejection fraction. Veno-occlusive unloading reduced myocardial infarct size and preserved LV ejection fraction in an experimental acute ischemia-reperfusion model. This proof-of-concept study demonstrated the potential of veno-occlusive unloading as an adjunctive cardioprotective therapy in patients undergoing revascularization for acute myocardial infarction.

The hemodynamic and metabolic effects of spironolactone treatment in acute kidney injury assessed by hyperpolarized MRI

Renal ischemia-reperfusion injury (IRI) is one of the most common types of acute kidney injury. Spironolactone has shown promising kidney protective effects in renal IRI in rats. We investigated the hemodynamic and metabolic effects of spironolactone (100 mg/kg) administered immediately after 40 min unilateral kidney ischemia in rats. Hyperpolarized MRI using co-polarized [1-¹³ C]pyruvate and [¹³ C,¹⁵ N₂ ]urea as well as ¹ H dynamic contrast-enhanced (DCE) MRI was performed 24 h after induction of ischemia. We found a significant decrease in renal blood flow (RBF) in the ischemic kidney compared with the contralateral one measured using DCE and [¹³ C,¹⁵ N₂ ]urea. The RBF measured using [1-¹³ C]pyruvate and [¹³ C,¹⁵ N₂ ]urea was significantly altered by spironolactone. The RBFs in the ischemic kidney compared with the contralateral kidney were decreased similarly as measured using both [¹³ C,¹⁵ N₂ ]urea and [1-¹³ C]pyruvate in the spironolactone-treated group. Spironolactone treatment increased the perfusion-corrected pyruvate metabolism by 54% in both the ischemic and contralateral kidney. Furthermore, we showed a correlation between vascular permeability using a histological Evans blue analysis and the ratio of the volumes of distribution (VoDs), ie VoD-[¹³ C,¹⁵ N₂ ]urea/VoD-[1-¹³ C]pyruvate. This suggests that [¹³ C,¹⁵ N₂ ]urea/[1-¹³ C]pyruvate VoD ratio may be a novel indicator of renal vascular permeability associated with renal damage in rodents.

Antioxidant and hepatoprotective effects of Korean ginseng extract GS-KG9 in a D-galactosamine-induced liver damage animal model

BACKGROUND/OBJECTIVES

This study was designed to investigate the improvement effect of white ginseng extract (GS-KG9) on D-galactosamine (Ga1N)-induced oxidative stress and liver injury.

SUBJECTS/METHODS

Sixty Sprague-Dawley rats were divided into 6 groups. Rats were orally administrated with GS-KG9 (300, 500, or 700 mg/kg) or silymarin (25 mg/kg) for 2 weeks. The rats of the GS-KG9- and silymarin-treated groups and a control group were then intraperitoneally injected Ga1N at a concentration of 650 mg/kg for 4 days. To investigate the protective effect of GS-KG9 against GalN-induced liver injury, blood liver function indicators, anti-oxidative stress indicators, and histopathological features were analyzed.

RESULTS

Serum biochemical analysis indicated that GS-KG9 ameliorated the elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) in GalN-treated rats. The hepatoprotective effects of GS-KG9 involved enhancing components of the hepatic antioxidant defense system, including glutathione, glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT). In addition, GS-KG9 treatment inhibited reactive oxygen species (ROS) production induced by GalN treatment in hepatocytes and significantly increased the expression levels of nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) proteins, which are antioxidant proteins. In particular, by histological analyses bases on hematoxylin and eosin, Masson's trichrome, α-smooth muscle actin, and transforming growth factor-β1 staining, we determined that the administration of 500 mg/kg GS-KG9 inhibited hepatic inflammation and fibrosis due to the excessive accumulation of collagen.

CONCLUSIONS

These findings demonstrate that GS-KG9 improves GalN-induced liver inflammation, necrosis, and fibrosis by attenuating oxidative stress. Therefore, GS-KG9 may be considered a useful candidate in the development of a natural preventive agent against liver injury.

Intermittent restraint-induced sympathetic activation attenuates hepatic steatosis and inflammation in a high-fat diet-fed mouse model

Nonalcoholic fatty liver disease (NAFLD) is very prevalent worldwide and is associated with insulin resistance and metabolic syndrome. Stress is a physiological and biological response to maintain homeostasis of the body against stressors while severe stress response is an important contributor to various illnesses, including metabolic syndrome and brain disorders. We have evaluated the effects of intermittent restraint stress on NAFLD in a high-fat diet (HFD)-fed mouse model. C57/BL6 mice had free access to a 60% HFD for 8 wk, with or without intermittent restraint stress (3 h) conducted three times a week. HFD administration increased fat accumulation in liver tissues. Unlike the stressed standard diet group, the levels of hepatic total cholesterol and triglycerides were significantly ameliorated in the HFD with stress group compared with the HFD alone group. These beneficial results were in accordance with serum levels of liver enzymes (aspartate transaminase, alanine transaminase) and hepatic levels of TNF-α and oxidative stress parameters (reactive oxygen species, nitric oxide, and malondialdehyde). The intermittent restraint stress significantly attenuated the HFD-derived alterations in serum insulin levels, hepatic protein kinase B activity, and gene expression, especially related to lipogenesis. This intermittent restraint stress also elevated the serum epinephrine concentration and activated the adrenergic receptor β2 or β3 in livers or white adipose tissue (WAT). Activation of energy expenditure markers (uncoupling protein 1, peroxisome proliferator-activated receptor-γ coactivator-1α) in brown adipose tissue and the browning of WAT were also observed in the HFD with stress group. Taken together, our findings showed the beneficial effects of sympathetic activation by intermittent restraint stress on HFD-induced hepatic steatosis and partial inflammation.NEW & NOTEWORTHY In modern society, stress is a part of daily life, and a certain level of stress is inevitable to most of the general population. Uncontrolled severe stress is obviously harmful; however, certain kind/level of stress could be beneficial on lipid metabolism via sympathetic activation. Our data suggest that a sympathetic activation by intermittent restraint stress could play a positive role in maintaining the balance of hepatic lipid metabolism, especially under high-fat diet conditions.

Myocardial strain assessed by feature tracking cardiac magnetic resonance in patients with a variety of cardiovascular diseases - A comparison with echocardiography

Myocardial deformation assessed by speckle tracking echocardiography (STE) is increasingly used for diagnosis, monitoring and prognosis in patients with clinical and pre-clinical cardiovascular diseases. Feature tracking cardiac magnetic resonance (FT-CMR) also allows myocardial deformation analysis. To clarify whether the two modalities can be used interchangeably, we compared myocardial deformation analysis by FT-CMR with STE in patients with a variety of cardiovascular diseases and healthy subjects. We included 40 patients and 10 healthy subjects undergoing cardiac magnetic resonance and echocardiographic examination for left ventricular volumetric assessment. We studied patients with heart failure and reduced ejection fraction (n = 10), acute perimyocarditis (n = 10), aortic valve stenosis (n = 10), and previous heart transplantation (n = 10) by global longitudinal (GLS), radial (GRS) and circumferential strain (GCS). Myocardial deformation analysis by FT-CMR was feasible in all but one participant. While GLS, GRS and GCS measured by FT-CMR correlated overall with STE (r = 0.74 and p < 0.001, r = 0.58 and p < 0.001, and r = 0.76 and p < 0.001), the correlations were not consistent within subgroups. GLS was systematically lower, whereas GRS and GCS were higher by FT-CMR compared to STE (p = 0.04 and p < 0.0001). Inter- and intra-observer reproducibility were comparable for FT-CMR and STE overall and across subgroups. In conclusion, myocardial deformation can be evaluated using FT-CMR applied to routine cine-CMR images in patients with a variety of cardiovascular diseases. However, correlation between FT-CMR and STE was modest and agreement was not optimal due to systematic bias regarding GLS and GCS. Consequently, FT-CMR and STE should not be used interchangeably for myocardial strain evaluation.

Clinical evaluation of anesthesia for high-risk cesarean section at a tertiary medical center: retrospective study for 8 years (2009-2016)

Objective

The number of high-risk pregnancies is increasing in tertiary medical centers. Therefore, we investigated perioperative outcomes based on risk factors to ascertain proper maternal and neonatal management.

Methods

We reviewed the medical records of patients receiving cesarean sections over an 8-year period. Clinical parameters for anesthesia and the neonatal outcome were compared among high-risk groups after subdivision by the number of clinical risk factors. The groups were as follows: group A (one risk factor), group B (two risk factors), and group C (three or more risk factors).

Results

Patient age, estimated blood loss (EBL), and volume of transfused red blood cell (RBC) were higher in group B than group A. Birth weight, 1- and 5-minute Apgar scores, and gestational age were lower while the frequency of neonatal intensive care unit (NICU) admission was higher in group B than group A. Group C patients were significantly older than group A or B patients. Birth weight, 1- and 5-minute Apgar scores and gestational age were significantly lower while frequency of NICU admission was higher in group C than group A and B.

Conclusion

The number of maternal risk factors was positively associated with adverse outcomes in the neonates.

Serum Cadmium Level Is Positively Associated with Unruptured Intracranial Aneurysm Incidence

Background

Cadmium is a toxic element in cigarette smoke associated with ischemic vascular disease. Its association with cerebral aneurysm is unknown.

Methods

We retrospectively analyzed the medical records of patients with headache who underwent imaging studies between March 2014 and August 2016. An unruptured intracranial aneurysm (UIA) was confirmed by brain magnetic resonance angiography or computed tomography angiography. A control group included age- and sex-matched patients without an UIA. Whole blood and random urine tests were used for detection of cadmium and arsenic levels, respectively. Student t-test was used to compare subject characteristics, mean cadmium and arsenic levels between groups, and differences between groups with small (<4-mm) and large (≥4-mm) UIAs. Multivariate regression analysis was used to identify risk factors for aneurysm incidence.

Results

Of 238 patients, 25 had an UIA. Those with an UIA had more pack-years of smoking (19.5±3.8 vs. 12.5±6.8, P=0.044) and higher mean serum cadmium levels (1.77±0.19 vs. 0.87±0.21 µg/L, P=0.027). Arsenic levels showed no difference between groups. (67.4±23.5 vs. 62.2±18.3 µg/L, P=0.458). There were no significantly different demographic, clinical, or laboratory characteristics between small and large aneurysm groups. According to multivariate analysis, smoking (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.06–2.33; P=0.047) and serum cadmium >2.0 mcg/L (OR, 1.39; 95% CI, 1.15–1.84; P=0.043) were associated with aneurysm incidence.

Conclusion

UIA incidence was associated with pack-years of smoking and serum cadmium level, but aneurysm size was not associated with serum cadmium level.

Test-retest repeatability of myocardial oxidative metabolism and efficiency using standalone dynamic 11C-acetate PET and multimodality approaches in healthy controls

BACKGROUND

Myocardial efficiency measured by 11C-acetate positron emission tomography (PET) has successfully been used in clinical research to quantify mechanoenergetic coupling. The objective of this study was to establish the repeatability of myocardial external efficiency (MEE) and work metabolic index (WMI) by non-invasive concepts.

METHODS AND RESULTS

Ten healthy volunteers (63 ± 4 years) were examined twice, one week apart, using 11C-acetate PET, cardiovascular magnetic resonance (CMR), and echocardiography. Myocardial oxygen consumption from PET was combined with stroke work data from CMR, echocardiography, or PET to obtain MEE and WMI for each modality. Repeatability was estimated as the coefficient of variation (CV) between test and retest. MEECMR, MEEEcho, and MEEPET values were 21.9 ± 2.7%, 16.4 ± 3.7%, and 23.8 ± 4.9%, respectively, P < .001. WMICMR, WMIEcho, and WMIPET values were 4.42 ± 0.90, 4.07 ± 0.63, and 4.58 ± 1.13 mmHg × mL/m2 × 106, respectively, P = .45. Repeatability for MEECMR was superior compared with MEEEcho but did not differ significantly compared with MEEPET (6.3% vs 12.9% and 9.4%, P = .04 and .25). CV values for WMICMR, WMIEcho, and WMIPET were 10.0%, 14.8%, and 12.0%, respectively, (P = .53).

CONCLUSIONS

Non-invasive measurements of MEE using 11C-acetate PET are highly repeatable. A PET-only approach did not differ significantly from CMR/PET and might facilitate further clinical research due to lower costs and broader applicability.

Hyperpolarized [1-13 C]pyruvate MRI can image the metabolic shift in cardiac metabolism between the fasted and fed state in a porcine model

PURPOSE

Owing to its noninvasive nature, hyperpolarized MRI may improve delineation of myocardial metabolic derangement in heart disease. However, consistency may depend on the changeable nature of cardiac metabolism in relation to whole-body metabolic state. This study investigates the impact of feeding status on cardiac hyperpolarized MRI in a large animal model resembling human physiology.

METHODS

Thirteen 30-kg pigs were subjected to an overnight fast, and 5 pigs were fed a carbohydrate-rich meal on the morning of the experiments. Vital parameters and blood samples were registered. All pigs were then scanned by hyperpolarized [1-¹³ C]pyruvate cardiac MRI, and results were compared between the 2 groups and correlated with circulating substrates and hormones.

RESULTS

The fed group had higher blood glucose concentration and mean arterial pressure than the fasted group. Plasma concentrations of free fatty acids (FFAs) were decreased in the fed group, whereas plasma insulin concentrations were similar between groups. Hyperpolarized MRI showed that fed animals had increased lactate/pyruvate, alanine/pyruvate, and bicarbonate/pyruvate ratios. Metabolic ratios correlated negatively with FFA levels.

CONCLUSION

Hyperpolarized MR can identify the effects of different metabolic states on cardiac metabolism in a large animal model. Unlike previous rodent studies, all metabolic derivatives of pyruvate increased in the myocardium of fed pigs. Carbohydrate-rich feeding seems to be a feasible model for standardized, large animal hyperpolarized MRI studies of myocardial carbohydrate metabolism.

Cardiac magnetic resonance characteristics in young survivors of aborted sudden cardiac death

PURPOSE

We aimed to identify and assess cardiac abnormalities by cardiovascular magnetic resonance (CMR) in a non-ischaemic aborted sudden cardiac death (SCD) population and to establish possible predictors of SCD.

METHODS

Thirty-six consecutive SCD survivors [median age 37.6 years (IQR 24.1-43.2), 31% female] with no previous cardiac history or evidence of ischaemic heart disease underwent CMR on day 6 (IQR 4-10) after admission. Data on ventricular volumes and the extent of late gadolinium enhancement (LGE) were collected. Systolic strain analysis was performed using feature tracking software.

RESULTS

Left ventricular (LV) and right ventricular (RV) indexed diastolic volumes were 92.9 ± 28.4 ml/m² and 94.1 ± 29 ml/m², respectively. LV ejection fraction (EF) and RV EF were 56.8 ± 10.7% and 53.7 ± 10.7%, respectively. Global peak endocardial longitudinal, circumferential, and radial strain were -17.9 ± 4.28%, -23.2 ± 5.8%, and 32.8 ± 10.6%, respectively. Compared to normal range, global longitudinal endocardial strain, longitudinal epicardial strain, circumferential endocardial strain, radial strain, and circumferential endocardial strain rate were impaired. Median volume of LGE was 0.25% (IQR 0.12-1.12) of the LV myocardium with highest prevalence in the inferolateral wall. Patients with cardiomyopathy diagnosis (n = 16) had lower LV strain rate compared to patients without cardiomyopathy (n = 20).

CONCLUSIONS

CMR findings in young patients with aborted SCD due to non-ischaemic heart disease seem to be minor. Although only present in small amounts, LGE appears to have a predilection towards the inferolateral wall in this population.

Effect of long-term remote ischemic conditioning in patients with chronic ischemic heart failure

Remote ischemic conditioning (RIC) protects against acute ischemia-reperfusion injury and may also have beneficial effects in patients with stable cardiovascular disease. We investigated the effect of long-term RIC treatment in patients with chronic ischaemic heart failure (CIHF). In a parallel group study, 22 patients with compensated CIHF and 21 matched control subjects without heart failure or ischemic heart disease were evaluated by cardiac magnetic resonance imaging, cardiopulmonary exercise testing, skeletal muscle function testing, blood pressure measurement and blood sampling before and after 28 ± 4 days of once daily RIC treatment. RIC was conducted as four cycles of 5 min upper arm ischemia followed by 5 min of reperfusion. RIC did not affect left ventricular ejection fraction (LVEF) or global longitudinal strain (GLS) in patients with CIHF (p = 0.63 and p = 0.11) or matched controls (p = 0.32 and p = 0.20). RIC improved GLS in the subgroup of patients with CIHF and with NT-proBNP plasma levels above the geometric mean of 372 ng/l (p = 0.04). RIC did not affect peak workload or oxygen uptake in either patients with CIHF (p = 0.26 and p = 0.59) or matched controls (p = 0.61 and p = 0.10). However, RIC improved skeletal muscle power in both groups (p = 0.02 for both). In patients with CIHF, RIC lowered systolic blood pressure (p < 0.01) and reduced NT-proBNP plasma levels (p = 0.02). Our findings suggest that long-term RIC treatment does not improve LVEF but increases skeletal muscle function and reduces blood pressure and NT-proBNP in patients with compensated CIHF. This should be investigated in a randomized sham-controlled trial.

Myocardial Oxygen Consumption and Efficiency in Aortic Valve Stenosis Patients With and Without Heart Failure

Background

Myocardial oxygen consumption (MVO₂) and its coupling to contractile work are fundamentals of cardiac function and may be involved causally in the transition from compensated left ventricular hypertrophy to failure. Nevertheless, these processes have not been studied previously in patients with aortic valve stenosis (AS).

Methods and Results

Participants underwent ¹¹C‐acetate positron emission tomography, cardiovascular magnetic resonance, and echocardiography to measure MVO₂ and myocardial external efficiency (MEE) defined as the ratio of left ventricular stroke work and the energy equivalent of MVO₂. We studied 10 healthy controls (group A), 37 asymptomatic AS patients with left ventricular ejection fraction ≥50% (group B), 12 symptomatic AS patients with left ventricular ejection fraction ≥50% (group C), and 9 symptomatic AS patients with left ventricular ejection fraction <50% (group D). MVO₂ did not differ among groups A, B, C, and D (0.105±0.02, 0.117±0.024, 0.129±0.032, and 0.104±0.026 mL/min per gram, respectively; P=0.07), whereas MEE was reduced in group D (21.0±1.6%, 22.3±3.3%, 22.1±4.2%, and 17.3±4.7%, respectively; P<0.05). Similarly, patients with global longitudinal strain greater than −12% and paradoxical low‐flow, low‐gradient AS had impaired MEE (P<0.05 versus controls). The ability to discriminate between symptomatic and asymptomatic patients was superior for global longitudinal strain compared with MVO₂ and MEE (area under the curve 0.98, 0.48, and 0.61, respectively; P<0.05).

Conclusions

AS patients display a persistent ability to maintain normal MVO₂ and MEE (ie, the ability to convert energy into stroke work); however, patients with left ventricular ejection fraction <50%; global longitudinal strain greater than −12%; or paradoxical low‐flow, low‐gradient AS demonstrate reduced MEE. These findings suggest that mitochondrial uncoupling contributes to the dismal prognosis in patients with reduced contractile function or paradoxical low‐flow, low‐gradient AS.

Evaluation of ECG-gated [(11)C]acetate PET for measuring left ventricular volumes, mass, and myocardial external efficiency

BACKGROUND

Noninvasive estimation of myocardial external efficiency (MEE) requires measurements of left ventricular (LV) oxygen consumption with [(11)C]acetate PET in addition to LV stroke volume and mass with cardiovascular magnetic resonance (CMR). Measuring LV geometry directly from ECG-gated [(11)C]acetate PET might enable MEE evaluation from a single PET scan. Therefore, we sought to establish the accuracy of measuring LV volumes, mass, and MEE directly from ECG-gated [(11)C]acetate PET.

METHODS

Thirty-five subjects with aortic valve stenosis underwent ECG-gated [(11)C]acetate PET and CMR. List mode PET data were rebinned into 16-bin ECG-gated uptake images before measuring LV volumes and mass using commercial software and compared to CMR. Dynamic datasets were used for calculation of mean LV oxygen consumption and MEE.

RESULTS

LV mass, volumes, and ejection fraction measured by CMR and PET correlated strongly (r = 0.86-0.92, P < .001 for all), but were underestimated by PET (P < .001 for all except ESV P = .79). PET-based MEE, corrected for bias, correlated fairly with PET/CMR-based MEE (r = 0.60, P < .001, bias -3 ± 21%, P = .56). PET-based MEE bias was strongly associated with LV wall thickness.

CONCLUSIONS

Although analysis-related improvements in accuracy are recommended, LV geometry estimated from ECG-gated [(11)C]acetate PET correlate excellently with CMR and can indeed be used to evaluate MEE.

Effect of Nicardipine on Haemodynamic and Bispectral Index Changes following Endotracheal Intubation

We investigated the effect of IV nicardipine on haemodynamic and bispectral index responses to the induction of general anaesthesia and intubation. Forty patients were randomly allocated to two groups of 20 to receive normal saline or nicardipine 15 μg/kg IV 30 s after induction. Ninety seconds later, tracheal intubation was performed. Systolic blood pressure, heart rate and bispectral index were measured at baseline, 1 min after induction, pre-intubation, and every minute until 5 min after endotracheal intubation. Rate–pressure product values were calculated. In the nicardipine group, systolic blood pressure decreased compared with the control group, and heart rate increased compared with the control group. Bispectral index and rate–pressure product showed no differences between the two groups. In conclusion, the administration of 15 μg/kg nicardipine IV does not affect anaesthetic depth in response to the induction of general anaesthesia and intubation.

Effect of Administration of Ketorolac and Local Anaesthetic Infiltration for Pain Relief after Laparoscopic-assisted Vaginal Hysterectomy

The efficacy of local anaesthetic infiltration and/or non-steroidal anti-inflammatory drugs for post-operative analgesia following laparoscopic-assisted vaginal hysterectomy (LAVH) was investigated in 83 patients, randomized into four groups in this double-blind, placebo-controlled study: group BK, local infiltration with bupivacaine and pre-incisional intramuscular (IM) ketorolac; group NN, saline local infiltration IM; group BN, local infiltration with bupivacaine and saline IM; group NK, local infiltration with saline and ketorolac IM. Post-operative pain scores were assessed at 1 h, 3 h, 6 h, 12 h and 24 h using a visual analogue scale (VAS). The major pain site, first analgesic request time and incidence of analgesic requests were also recorded. At 1 h, 3 h and 6 h after surgery, group BK patients had significantly lower VAS pain scores than group NN patients. The first analgesic request time was significantly longer in group BK than in groups NN, BN and NK. Pre-incisional treatment with ketorolac IM and local infiltration with bupivacaine reduced post-operative pain after LAVH.

A dual tracer (68)Ga-DOTANOC PET/CT and (18)F-FDG PET/CT pilot study for detection of cardiac sarcoidosis

Background

Cardiac sarcoidosis (CS) is a potentially fatal condition lacking a single test with acceptable diagnostic accuracy. ¹⁸F-FDG PET/CT has emerged as a promising imaging modality, but is challenged by physiological myocardial glucose uptake. An alternative tracer, ⁶⁸Ga-DOTANOC, binds to somatostatin receptors on inflammatory cells in sarcoid granulomas. We therefore aimed to conduct a proof-of-concept study using ⁶⁸Ga-DOTANOC to diagnose CS. In addition, we compared diagnostic accuracy and inter-observer variability of ⁶⁸Ga-DOTANOC vs. ¹⁸F-FDG PET/CT.

Methods

Nineteen patients (seven female) with suspected CS were prospectively recruited and dual tracer scanned within 7 days. PET images were reviewed by four expert readers for signs of CS and compared to the reference standard (Japanese ministry of Health and Welfare CS criteria).

Results

CS was diagnosed in 3/19 patients. By consensus, 11/19 ¹⁸F-FDG scans and 0/19 ⁶⁸Ga-DOTANOC scans were rated as inconclusive. The sensitivity of ¹⁸F-FDG PET for diagnosing CS was 33 %, specificity was 88 %, PPV was 33 %, NPV was 88 %, and diagnostic accuracy was 79 %. For ⁶⁸Ga-DOTANOC, accuracy was 100 %. Inter-observer agreement was poor for ¹⁸F-FDG PET (Fleiss’ combined kappa 0.27, NS) and significantly better for ⁶⁸Ga-DOTANOC (Fleiss’ combined kappa 0.46, p = 0.001).

Conclusions

Despite prolonged pre-scan fasting, a large proportion of ¹⁸F-FDG PET/CT images were rated as inconclusive, resulting in low agreement among reviewers and correspondingly poor diagnostic accuracy. By contrast, ⁶⁸Ga-DOTANOC PET/CT had excellent diagnostic accuracy with the caveat that inter-observer variability was still significant. Nevertheless, ⁶⁸Ga-DOTANOC PET/CT looks very promising as an alternative CS PET tracer.

Trial registration

Current Controlled Trials NCT01729169.

Electronic supplementary material

The online version of this article (doi:10.1186/s13550-016-0207-6) contains supplementary material, which is available to authorized users.

Automatic Extraction of Myocardial Mass and Volume Using Parametric Images from Dynamic Nongated PET

Dynamic cardiac PET is used to quantify molecular processes in vivo. However, measurements of left ventricular (LV) mass and volume require electrocardiogram-gated PET data. The aim of this study was to explore the feasibility of measuring LV geometry using nongated dynamic cardiac PET.

METHODS

Thirty-five patients with aortic-valve stenosis and 10 healthy controls underwent a 27-min (11)C-acetate PET/CT scan and cardiac MRI (CMR). The controls were scanned twice to assess repeatability. Parametric images of uptake rate K1 and the blood pool were generated from nongated dynamic data. Using software-based structure recognition, the LV wall was automatically segmented from K1 images to derive functional assessments of LV mass (mLV) and wall thickness. End-systolic and end-diastolic volumes were calculated using blood pool images and applied to obtain stroke volume and LV ejection fraction (LVEF). PET measurements were compared with CMR.

RESULTS

High, linear correlations were found for LV mass (r = 0.95), end-systolic volume (r = 0.93), and end-diastolic volume (r = 0.90), and slightly lower correlations were found for stroke volume (r = 0.74), LVEF (r = 0.81), and thickness (r = 0.78). Bland-Altman analyses showed significant differences for mLV and thickness only and an overestimation for LVEF at lower values. Intra- and interobserver correlations were greater than 0.95 for all PET measurements. PET repeatability accuracy in the controls was comparable to CMR.

CONCLUSION

LV mass and volume are accurately and automatically generated from dynamic (11)C-acetate PET without electrocardiogram gating. This method can be incorporated in a standard routine without any additional workload and can, in theory, be extended to other PET tracers.

Cardiovascular MR T2-STIR imaging does not discriminate between intramyocardial haemorrhage and microvascular obstruction during the subacute phase of a reperfused myocardial infarction

Objective

Microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH) are known complications of myocardial ischaemia-reperfusion injury. Whereas MVO is an established marker for a poor clinical outcome, the clinical significance of IMH remains less well defined. Cardiovascular MR (CMR) and T2 weighted short tau inversion recovery (T2-STIR) imaging have been used to detect IMH and to explore its clinical importance. IMH is typically identified within the area-at-risk as a hypointense signal core on T2-STIR images. Because MVO will also appear as a hypointense signal core, T2-STIR imaging may not be an optimal method for assessing IMH. In this study, we sought to investigate the ability of T2-STIR to discriminate between MVO with IMH in a porcine myocardial ischaemia-reperfusion model that expressed MVO with and without IMH.

Method

MVO with and without IMH (defined from both macroscopic evaluation and T1 weighted CMR) was produced in 13 pigs by a 65-min balloon occlusion of the mid left anterior descending artery, followed by reperfusion. Eight days after injury, all pigs underwent CMR imaging and subsequently the hearts were assessed by gross pathology.

Results

CMR identified MVO in all hearts. CMR and pathology showed that IMH was present in 6 of 13 (46%) infarcts. The sensitivity and specificity of T2-STIR hypointense signal core for identification of IMH was 100% and 29%, respectively. T2-values between hypointense signal core in the pigs with and without IMH were similar (60.4±3 ms vs 63.0±4 ms).

Conclusions

T2-STIR did not allow identification of IMH in areas with MVO in a porcine model of myocardial ischaemic/reperfusion injury in the subacute phase of a reperfused myocardial infarction.

Uterine rupture during labor in women with twice successful vaginal births after cesarean delivery

Uterine rupture during labor is a serious complication resulting in maternal and neonatal morbidity and mortality. We present the extremely rare case of a 38-year-old gravid woman admitted with labor pain at term, about to experience a uterine rupture during labor. She had previously twice delivered vaginally, and during her third pregnancy had a low transverse Cesarean section. Prior to arriving at the hospital with labor pains, she had routine prenatal care with normal prenatal laboratory tests. One day the woman reported to having sudden epigastric pain, and 40 minutes after her admission a pelvic exam was completed. The unborn baby had a persistent revealed, and a live neonate was promptly delivered with an Apgar score of 1 at one minute and 5 at five minutes. On the fifth postoperative day the woman and her baby were discharged home with no maternal and neonatal complications.

Coke tolerance of Ni/Al2O3 nanosheet catalyst for dry reforming of methane

In the dry reforming of methane with CO₂, Ni/Al₂O₃ nanosheet catalysts exhibited excellent coke tolerance, showing stability even in the presence of a large amount of coke because of the large intersheet pores.

Myocardial oedema in acute myocarditis detected by echocardiographic 2D myocardial deformation analysis

AIMS

The clinical diagnosis of acute myocarditis is based on symptoms, electrocardiography, elevated myocardial necrosis biomarkers, and echocardiography. Often, conventional echocardiography reveals no obvious changes in global cardiac function and therefore has limited diagnostic value. Myocardial deformation imaging by echocardiography is an evolving method used to characterize quantitatively longitudinal systolic function, which may be affected in acute myocarditis. The aim of our study was to assess the utility of echocardiographic deformation imaging of the left ventricle in patients with diagnosed acute myocarditis in whom cardiovascular magnetic resonance (CMR) evaluation was performed.

METHODS AND RESULTS

We included 28 consecutive patients (mean age 32 ± 13 years) with CMR-verified diagnosis of acute myocarditis according to the Lake Louise criteria. Cardiac function was evaluated by a comprehensive assessment of left ventricular (LV) function, including 2D speckle-tracking echocardiography. We found no significant correlation between the peak values of cardiac enzymes and the amount of myocardial oedema assessed by CMR (troponin: r= 0.3; P = 0.05 and CK-MB: r = 0.1; P = 0.3). We found a larger amount of myocardial oedema in the basal part of the left ventricle [American Heart Association (AHA) segments 1-6] in inferolateral and inferior segments, compared with the anterior, anterolateral, anteroseptal, and inferoseptal segments. In the mid LV segments (AHA segments 7-12), this was more pronounced in the anterior, anterolateral, and inferolateral segments. Among conventional echocardiographic parameters, LV function was not found to correlate with the amount of myocardial oedema of the left ventricle. In contrast, we found the wall motion score index to be significantly correlated with the amount of myocardial oedema, but this correlation was only present in patients with an extensive amount of oedema (>11% of the total left ventricle). Global longitudinal systolic myocardial strain correlated significantly with the amount of oedema (r = 0.65; P < 0.001). We found that both the epicardial longitudinal and the endocardial longitudinal systolic strains were significantly correlated with oedema (r = 0.55; P = 0.003 and r = 0.54; P < 0.001).

CONCLUSION

In patients with acute myocarditis, 2D speckle-tracking echocardiography was a useful tool in the diagnostic process of acute myocarditis. Global longitudinal strain adds important information that can support clinical and conventional echocardiographic evaluation, especially in patients with preserved LV ejection fraction in relation to the diagnosis and degree of myocardial dysfunction.