Cardiovascular Rehabilitation With a WCD-Data From the CR3 Study (Cardiac Rehab Retrospective Review)

PURPOSE

Patients at risk for sudden cardiac death may temporarily need a wearable cardioverter-defibrillator (WCD). Exercise-based cardiac rehabilitation (CR) has a class I recommendation in patients with cardiac disease. The aim of this study was to evaluate the safety and feasibility of undergoing CR with a WCD.

METHODS

We performed a retrospective analysis of all patients with a WCD who completed a CR in Austria (2010-2020).

RESULTS

Patients (n = 55, 60 ± 11 yr, 16% female) with a median baseline left ventricular ejection fraction (LVEF) of 36 (30, 41)% at the start of CR showed a daily WCD wearing duration of 23.4 (22, 24) hr. There were 2848 (8 [1, 26]/patient) automatic alarms and 340 (3 [1, 7]/patient) manual alarms generated. No shocks were delivered by the WCD during the CR period. One patient had recurrent hemodynamically tolerated ventricular tachycardias that were controlled with antiarrhythmic drugs.No severe WCD-associated adverse events occurred during the CR stay of a median 28 (28, 28) d. The fabric garment and the device setting needed to be adjusted in two patients to diminish inappropriate automatic alarms. Left ventricular ejection fraction after CR increased significantly to 42 (30, 44)% ( P < .001). Wearable cardioverter-defibrillator therapy was stopped due to LVEF restitution in 53% of patients. In 36% of patients an implantable cardioverter-defibrillator was implanted, 6% had LVEF improvement after coronary revascularization, one patient received a heart transplantation (2%), two patients discontinued WCD treatment at their own request (4%).

CONCLUSION

Completing CR is feasible and safe for WCD patients and may contribute positively to the restitution of cardiac function.

Prevention of early sudden cardiac death after myocardial infarction using the wearable cardioverter defibrillator - results from a real-life cohort

Funding Acknowledgements

Type of funding sources: None.

Background

Patients are at elevated risk of sudden cardiac death (SCD) after acute myocardial infarction (MI). The VEST trial failed to show a significant reduction in arrhythmic mortality in patients prescribed with a wearable converter-defibrillator (WCD), having a lower than expected wearing compliance. We aimed to investigate the incidence of WCD treatments and outcomes of all patients with acute MI and LVEF ≤35% in a real life and well-compliant cohort in Austria.

Methods

We performed a retrospective analysis of all patients meeting the in- and exclusion criteria of the original VEST trial within the Austrian WCD registry between 2010 and 2021.

Results

105/896 patients (12%) with an average age of 64±11 years (12% female; LVEF 28±6%) registered in the Austrian WCD registry met the VEST in- and exclusion criteria. 104/105 patients were revascularized and prescribed with a WCD prescription for 69 (1;277) days, the median wearing duration was 23.5 (0;24) hours/day. 4/105 (3.8%) patients received 9 appropriate WCD shocks, the per patient shock rate was 2 (1;5). No inappropriate shock was delivered. During follow-up, 46/105 patients (44%) received an ICD after the WCD period, 4/105 (3.8%) patients died during follow-up. Arrhythmic mortality (1.9% Austria vs. 1.6% VEST, p=ns), as well as all-cause mortality (3.8% vs. 3.1%, p=ns) in the Austrian cohort were comparable to the VEST cohort.

Conclusion

The WCD is a safe treatment option in a highly selected cohort of patients with a LVEF ≤35% after acute myocardial infarction. However, despite excellent WCD compliance as opposed to the VEST study, only 3.8% of patients receive appropriate WCD shocks and the arrhythmic mortality rate was not significantly improved.

Ertugliflozin to reduce arrhythmic burden in ICD/CRT patients (ERASe-trial). a phase III study

Background and aim

Sodium glucose cotransporter 2 (SGLT2) have proven profound positive effects in heart failure with reduced ejection fraction (HFrEF). These effects are independent from the presence of diabetes. Since SGLT2 receptors are not expressed in human myocardium, these cardioprotective effects be indirect or pleiotropic. Besides metabolic effects anti-inflammatory anti-fibrotic properties are discussed.

Despite a strong correlation of ventricular arrhythmias with HFrEF, the impact of ertugliflozin on the arrhythmic burden has not been investigated, yet. Therefore, the Ertugliflozin to Reduce Arrhythmic burden in ICD/CRT patientS (ERASe) trial was designed to investigate the efficacy and safety of ertugliflozin in diabetic and non-diabetic HFrEF patients.

Methods

Methods: Within a multicentre, national, randomized, double-blind, placebo-controlled, phase 3b trial we aim to enrol a total of 402 patients across Austria. Patients with HFrEF or HFmrEF and ICD±CRT therapy &gt;3 months and previous ventricular tachycardia (at least 10 documented non-sustained VT episodes within the last 12 months) are randomized in a 1:1 ratio to ertugliflozin (5mg once daily orally administered) or matching placebo.

The primary endpoint of the ERASe trial is to investigate the impact of Ertugliflozin on total burden of ventricular arrhythmias. Further objectives will be the number of therapeutic interventions of implanted devices, atrial fibrillation, heart failure biomarker and changes in physical function quality of life, stress and anxiety.

Conclusion

The ERASe trial will be the first trial to test ertugliflozin in heart failure patients with non-preserved ejection fraction and ongoing ICD/CRT therapy regardless of their diabetic status. The ERASe trial may therefore extend the concept of SGLT2 inhibition to improve cardiac reverse remodelling, including reduced arrhythmic burden.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): unrestricted grant of MSD

Reciprocal communication of perivascular epicardial adipose tissue and coronary atherogenesis

Purpose

Perivascular epicardial adipose tissue (PEAT) has been linked to underlying coronary artery disease (CAD) and proposed to modulate adjacent atherosclerotic plaque formation. In vitro and ex vivo studies support bilateral influence of adipose tissue and vessel wall. Therefore, we quantified PEAT volume and composition and its dynamics in a low coronary risk patient cohort with a semi-automate software in serial CT exams.

Methods and materials

We retrospectively included 120 patients (27% females) from a tertiary care hospital who underwent serial cardiac CT angiographies with a low cardiovascular risk profile. All coronary CTs were evaluated in a standardized approach: epicardial adipose tissue (EAT) volume and attenuation was quantified in total, in the atrioventricular (RCA, LCX) or interventricular (LAD) sulcus and in a 5mm radius for each coronary artery (PEAT). Coronary plaques were quantified using a semi-automated software and compared to progression, stability of regression between the two scans. The measurements were compared on a per-patient and per-vessel basis between plaque-naïve and diseased vessels.

Results

Of 120 patients (32% female), 59.2%) had atherosclerotic plaque formation. After 36 months mean follow-up, 22 (18.3%) showed a CAD regression plaques, 39 (32.5%) had stable coronary arteries and 49 (40.8%) progressive CAD. Total EAT volume decreased by −15.6±37.2 mm3 in the regressive group, increased by 2.7±30.6mm3 in the stable group and by 24.3±37.1mm3 in the progressive CAD group (p=0.003).

Per-vessel analysis showed a significant decrease of perivascular EAT attenuation in patients with CAD regression (−3.8±7.6 HU) compared to CAD stable (1.2±9.1 HU) and CAD progressive patients (3.5±8.2 HU, p&lt;0.0001). Mean sulcus EAT attenuation did not show a significant change at follow-up (p=0.135)

Conclusion

Epicardial adipose tissue volume is mutually changing with the progression or regression of coronary artery disease. Perivascular but not epicardial attenuation levels correlated to adjacent plaque and support a direct bilateral influence.

Change per-vessel-basis (n=360)

Funding Acknowledgement

Type of funding source: None

P534Central sleep apnea in pacing-induced cardiomyopathy: prevalence, improvement by upgrading to cardiac resynchronisation therapy and impact on structural responder rates and long-term outcome

Funding Acknowledgements

ÖNB Jubiläumsfondsprojekt Nr. 15974, ISR grant by Boston Scientific, St. Paul, MN, USA

Background

Central sleep apnea (CSA) in pacing induced cardiomyopathy (PICM) is poorly studied. Specifically, it is unknown whether upgrading from right ventricular pacing (RVP) to cardiac resynchronisation therapy (CRT) improves CSA.

Methods

Fifty-three patients with impaired left ventricular ejection fraction, frequent right ventricular pacing due to high-grade atrioventricular block and heart failure symptoms despite optimal medical therapy underwent upgrading to CRT. Within one month after left ventricular lead implantation (but still not activated), sleep apnea was assessed in all participants by single-night polysomnography (PSG). Nineteen patients with moderate or severe CSA defined by an apnea hypopnea index (AHI) &gt; 15 events per hour were re-scheduled for a follow up PSG 3-5 months after initiation of cardiac resynchronization therapy. Of this cohort, thirteen patients with stable mild heart failure agreed to be randomized to CRT versus RVP in a cross-over design.

Results

CSA (AHI &gt; 5 events per hour) was diagnosed in 26 (49.1%), OSA in 16 (30.2%) patients suffering from PICM . Eleven (20.8%) patients did not have any form of sleep apnea. Moderate to severe CSA (AHI &gt; 15 events per hour) was significantly improved (without specific CPAP therapy) by 102 (96-172) days of CRT: AHI decreased from 39.4 events per hour at baseline to 21.6 by CRT (p &lt; 0.001). Furthermore, CRT led to a substantial decrease in left ventricular endsystolic volumes: baseline 141 ml (103-155), significant improvement under CRT (102 ml, 65-138; p &lt; 0.001), whereas no effect with ongoing RV-pacing (147 ml, 130-161; p = 0.865). Preexistent CSA did not affect the structural response of CRT (56.5% in patients with CSA, 62.5% of patients with obstructive sleep apnea and 54.5% in patients without sleep apnea; p = 0.901) and had no impact on major adverse cardiac events (p = 0.412) and/or survival (p = 0.623) during long-term follow-up.

Conclusions

CSA is highly prevalent in patients with PICM and is significantly improved by upgrading to CRT. Preexistent CSA does not hamper structural improvement and long-term outcome after upgrading to CRT. Thus, CSA seems to occur as a consequence of PICM, rather than as a pathophysiological mediator.

Abstract Figure.

917Appropriate shocks in WCD patients - Results from the Austrian WCD registry

Background

The wearable cardioverter-defibrillator (WCD) is a temporary treatment option for patients at high risk for sudden cardiac death (SCD) and/or for patients in whom implantation of a cardioverter defibrillator (ICD) is temporarily not possible.

Purpose

To investigate incidence and predictors of appropriate WCD shocks.

Methods

We performed a retrospective analysis of all patients with appropriate shocks delivered by a WCD in the cohort of the Austrian WCD registry between 2010 and 2018. Within this dataset, we identified predictors within the baseline characteristics, the indication for the WCD and preceding alarms automatically recorded by the WCD.

Results: Baseline

Within 879 registered in the Austrian WCD registry, 31 patients (3,5%) received appropriate WCD shocks due to ventricular tachycardia (VT) or ventricular fibrillation (VF). Compared to the total cohort, shocked patients were elder (mean age 67 ± 14 vs. 60 ± 14 years, p = 0,001) and the percentage of female patients was lower (11% vs. 21%, p = 0,262). The mean baseline LVEF at prescription was 33 ± 15% in the population with appropriate shocks compared to 32 ± 14% in the all-over cohort (p = ns).

In the Austrian WCD population, 378/879 patients had a WCD due to secondary prevention. Within this cohort 5,6% (21/378) had shocks for VT/VF again, compared to 10/501 (2%) shocked patients in the primary prevention cohort. 31/879 (3.5%) patients received 57 appropriate shocks, the per patient shock rate was 2 [1;5]. These shocks were induced by 25 ventricular tachycardia and 26 times ventricular fibrillation.

The octagenarians with 11% (7/34) shocked patients, showed a significant higher likelihood to receive shocks (p = 0,008) as well as the cohort of secondary preventive prescribed WCD-patients (p = 0,007). There were more shocks in patients, when prescribed with a WCD due to ICD associated infections (p = 0,001), when used as a bridge to ICD (p = 0,042) and in patients with ongoing risk stratification (p = 0,009).

Looking through the automatically recorded alarms preceding a WCD shock, shocked patients experienced significantly more often non sustained VTs (p &lt; 0,0005) and sustained VTs that were haemodynamically tolerated and did not require a treatment (p &lt; 0,0005).

Conclusion

The WCD is effective in preventing SCD and an important risk stratification tool. We identified advanced age, patients with either already confirmed indication for ICD implantation (either temporary contraindication for implantation or temporary explantation) or risk stratification of an unclear cardiomyopathy, the cohort of secondary prevention and preceding nsVTs and stable VTs as predictors for appropriate WCD therapies.

P2280Incidence and predictors of alarms in patients with wearable cardioverter defibrillator (WCD) - results of the Austrian WCD Registry

Background

The wearable cardioverter-defibrillator (WCD) is a treatment option for patients at high risk for ventricular arrhythmia, either if the risk is potentially reversible or if an implantable cardioverter defibrillator (ICD) implantation is currently not possible.

Methods

We performed a retrospective analysis of all alarms in the cohort of the Austrian WCD registry between 2010 and 2018. Type of arrhythmias was assessed by independent review of two cardiologists.

Results

25.540 automatically recorded ECGs in 605 patients (68%) were analyzed. 1125 ECGs showed sustained ventricular arrhythmias in 117 patients, 65 ECGs showed non sustained VTs.

24.415 ECGs in 488 patients showed inadequate alarms Reasons for inadequate alarms were artefacts (97%), pacemaker or t-wave oversensing (0,3%) and in 2,3% atrial fibrillation or SVTs.

5860 manually recorded ECGs in 608 patients (68%) were analyzed. 298 (5%) of these ECGs showed following arrhythmias: atrial fibrillation (34,7%), SVTs (28%), sinustachycardia (10,7%), non sustained VTs (12%) and sustained VTs or sustained slow VTs (6,7%), premature ventricular beats or bradycardia was identified in 8%. The remaining 5562 ECGs (95%) showed normal sinus rhythm.

Of the 895 patients (60±14 years, 20% female), 34 (3,8%) received a total of 65 automatically triggered shocks (median 2; range 1–5). 31/895 (3.5%) patients received 57 appropriate shocks (median 1, range 1–5) for 49 arrhythmic events, whereas 7/895 (0.8%) patients received 8 inappropriate shocks (median 1, range 1–2).

44 events were successfully terminated with the first shock (85,7%) and 4 events were terminated with the second shock. In one patient, a shock treatment for VF was not successful. The time from event onset to shock was median 60 [40; 1187] sec.

The median time from WCD prescription to a shock event was 8 days [1–151]. 23/ 34 patients (68%) received their first WCD shock within 30 days.

Seven patients (0.8%) received a total of nine inappropriate shocks due to different reasons: artefacts (2 inappropriate shocks), non-shockable rhythms (asystole, weak action, 3 shocks) and atrial fibrillation with a bundle branch block in two cases. In one patient VF terminated spontaneously before the WCD treatment was delivered.

Conclusion

The WCD is an effective treatment option in patients with a high SCD risk but it also triggers a significant amount of alarms. Although many inadequate alarms occurred, adequate alarms led to arrhythmia detection such as in VT/VF events which were successfully terminated by the WCD in 3,4% of patients.

P6163Promotion of coronary plaque progression associated with different anticoagulation agents - a longitudinal CTA analysis

Objective

Possible antithrombotic effect of anticoagulants in coronary artery disease have been proposed but mechanism are poorly understood. Experimental and clinical data indicate a key role of coagulation factors in the progression of atherosclerosis. We sought to evaluate the effect of different oral anticoagulation agents on the progression of atherosclerosis.

Methods

This retrospective matched case controlled study included patients with atrial fibrillation (AF) who underwent repeated CT angiography for ablation planning. Patients with known structural cardiac pathologies or significant comorbidities were excluded.

Patients were stratified according to their anticoagulation into 3 groups: vitamin K antagonist (VKA), direct oral anticoagulation (DOAC) and control (CR; aspirin or no therapy) with equal distribution of age and cardiovascular risk factors. Baseline and follow-up CT exams for repeated AF ablations were evaluated for the CAD profile and (semi)automated quantitative plaque analysis.

Results

One-hundred sixty-one patients were included (mean CT time interval: 31 months). The three cohorts did not differ in patient characteristics or CT findings at baseline. Absolute plaque volume progression was significantly higher in patients using VKA (66.5±136.7 mm3) compared to both CR (27.2±73.6 mm3) and DOAC (−7.1±42.1 mm3, p<0.001), translating into an annual change of 23.2±47.0 mm3 for VKA, 12.3±4.3 mm3 for CR and −4.6±22.9 mm3 for DOAC (p=0.003). The number of affected segments (SIS) increased by 1.2±1.3 compared to 0.6±1.3 in the control group and 0.2±0.7 in the DOAC group (p<0.0001).

Baseline CTA findings Control (n=61) DOAC (n=50) VKA (n=50) p Vessel Volume (mm3) 26.9±42.9 23.1±43.3 27.9±40.7 0.85 Lumen Volume (mm3) 15.7±24.8 13.3±25.1 16.6±27.0 0.82 Coronary Calcium Score (AU) 63.4±187.2 42.0±114.6 53.8±118.6 0.75 Segment Involvement Score 1.8±2.1 1.8±2.3 1.9±2.2 0.96 Stenosis Average Area (%) 19.0±21.7 0.5±0.7 0.5±0.7 0.71 Maximal Plaque Thickness (mm3) 0.5±0.7 0.5±0.7 0.5±0.7 0.69 Total Plaque Volume (mm3) 33.6±60.0 30.0±55.6 34.2±48.0 0.92 AU, Agatston units; DOAC, direct oral anticoagulation; SIS, segment involvement score; VKA, vitamin K antagonist.

Changes between baseline and follow-up

Conclusion

In serial coronary CTs, patients using vitamin K antagonists showed the highest plaque volume progression while patients using a direct oral anticoagulant showed a regression of total plaque volume. Therefore, direct anticoagulation may have a beneficial effect on atherosclerosis.

ADMA regulates angiogenesis: genetic and metabolic evidence

Endothelium-derived nitric oxide (NO) plays an important role in transducing the effects of angiogenic factors. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase (NOS). We used a murine model of hindlimb ischemia to investigate whether genetic or metabolic changes in ADMA levels could impair angiogenic response in vivo. Hindlimb ischemia was surgically induced in C57BL/6J mice, apo E-deficient mice, or transgenic mice overexpressing dimethylarginine dimethylaminohydrolase (DDAH). Some animals were also treated with the NOS antagonist L-nitro-arginine, or the NO precursor L-arginine. Angiogenesis was quantified in the hindlimb skeletal muscle by capillary/myocyte ratio. Plasma or tissue ADMA levels were measured by HPLC. In normal mice, hindlimb ischemia increased tissue ADMA twofold, and reduced DDAH and NOS expression. This was associated with a reduced NOS activity (by over 80%) three days following surgery. On day seven, a threefold increase in DDAH expression and a fall in tissue ADMA levels were associated with a sevenfold increase in NOS activity, whereas NOS expression did not increase above baseline. In DDAH transgenic mice, the elevation of ADMA and decrement in NOS activity was blunted during hindlimb ischemia. Plasma ADMA levels were increased in apo E-mice (1.79 ± 0.45 versus 1.07 ± 0.08 μmol/l; p = 0.008). Capillary index was significantly reduced in apo E-mice up to seven weeks after surgery (0.25 ± 0.05 versus 0.62 ± 0.08; p < 0.001). The effect of hypercholesterolemia on capillary index was reversed by L-arginine, and (in wild-type mice) mimicked by administration of the NOS antagonist L-nitro-arginine. In conclusion, metabolic or genetic changes in plasma and tissue ADMA levels affect tissue NO production and angiogenic response to ischemia.

CoolLoop® First: A First In Man Study To Test A Novel Circular Cryoablation System In Paroxysmal Atrial Fibrillation

INTRODUCTION

Pulmonary vein (PV) isolation is the mainstay of catheter treatment of paroxysmal atrial fibrillation (AF). The CoolLoop® cryoablation catheter (AFreeze® GmbH; Innsbruck, Austria) was developed to create wide and complete circular lesions around the PVs. In this study we evaluated feasibility and safety of this novel ablation system in humans.

METHODS

10 patients (6M/4F; 57.6±7.6y) with paroxysmal AF were included in 2 referral centers. The CoolLoop® catheter was positioned at each PV antrum using a steerable transseptal sheath. Subsequently, 2-6 double-freezes over 5min were performed at each vein and PV-isolation was assessed thereafter using a circular mapping catheter. During cryoablation of the right PVs, pacing was used to monitor phrenic nerve function.

RESULTS

The CoolLoop® catheter could be successfully positioned at each PV. A mean of 5.6±1.8 cryoablations were performed in the LSPV, 5.2±1.6 in the LIPV, 6.3±2.5 in the RSPV and 5.4±1.6 in the RIPV, respectively. Mean procedure time was 251±60min and mean fluoroscopy time was 44.0±13.2min. 6 / 10 LSPV, 6 / 10 LIPV, 5 / 10 RSPV and 6 / 10 RIPV could be isolated exclusively using the novel cryoablation system. One patient developed groin hematoma and a brief episode of ST-elevation due to air embolism was observed in another subject. No other clinical complications occurred during 3 months of follow up.

CONCLUSIONS

PV-isolation for paroxysmal atrial fibrillation using the CoolLoop® catheter is feasible and appears safe. Clinical long term efficacy still needs to be evaluated and will be compared with established catheters used for AF ablation.

Single-beat noninvasive imaging of cardiac electrophysiology of ventricular pre-excitation

OBJECTIVES

The aim of this study was to determine whether noninvasive imaging of cardiac electrophysiology (NICE) is feasible in patients with Wolff-Parkinson-White (WPW) syndrome in the clinical setting of a catheter laboratory and to test the accuracy of the noninvasively obtained ventricular activation sequences as compared with that of standard invasive electroanatomic mapping.

BACKGROUND

NICE of ventricular activation could serve as a useful tool in the treatment of cardiac arrhythmias and might help improve our understanding of arrhythmia mechanisms.

METHODS

NICE works by fusing the data from high-resolution electrocardiographic mapping and a model of the patient's cardiac anatomy obtained by magnetic resonance imaging. The ventricular activation sequence was computed with a bidomain theory-based heart model to solve this inverse problem. Noninvasive imaging of cardiac electrophysiology was performed in 7 patients with WPW syndrome undergoing catheter ablation of the accessory pathway. The position error of NICE was defined as the distance between the site of earliest activation computed by NICE and the successful ablation site identified by electroanatomic mapping (CARTO; Biosense Webster, Diamond Bar, California) for normal atrioventricular (AV) conduction as well as for adenosine-induced AV block.

RESULTS

The error introduced by geometric coupling of the CARTO data and the NICE model was 5 +/- 3 mm (model discretization 10 mm). All ventricular accessory pathway insertion sites were identified with an accuracy of 18.7 +/- 5.8 mm (baseline) and 18.7 +/- 6.4 mm (adenosine).

CONCLUSIONS

The individual cardiac anatomy model obtained for each patient enables accurate noninvasive electrocardiographic imaging of ventricular pre-excitation in patients with WPW syndrome. Noninvasive imaging of cardiac electrophysiology might be used as a complementary noninvasive approach to localize the origin and help identify and understand the underlying mechanisms of cardiac arrhythmias.

Reduction of postchallenge hyperglycaemia prevents acute endothelial dysfunction in subjects with impaired glucose tolerance

OBJECTIVES

To investigate whether selective reduction of postchallenge hyperglycaemia influences acute endothelial dysfunction, a very early manifestation of vascular disease, in patients with impaired glucose tolerance.

METHODS

In a randomized, double-blind, placebo-controlled, cross-over study the acute effect of 200-mg acarbose was investigated in 28 subjects with diagnosed impaired glucose tolerance. Flow-mediated dilation (FMD) of the brachial artery was determined as a measure of endothelial function before and 2 and 3 h after ingestion of 100-g saccharose. Asymmetrical dimethylarginine (ADMA) was measured by high-performance liquid chromatography.

RESULTS

A negative correlation was observed between the changes of glucose and FMD (r = 0.416, P = 0.0018) 2 h after ingestion of saccharose. At 3 h, neither blood glucose nor FMD were different from baseline. Changes of both blood glucose (P = 0.0007) and FMD (P = 0.046) were significantly lower after administration of acarbose. Subgroup analysis revealed that the effect of acarbose was restricted to those subjects with an increase of blood glucose above the median increase of glycaemia. No changes of plasma ADMA were observed.

CONCLUSIONS

Our data clearly demonstrate that the postchallenge alteration of vascular function in patients with impaired glucose tolerance is caused by the acute elevation of glycaemia but not mediated by ADMA.

Docosahexaenoic acid restores endothelial function in children with hyperlipidemia: results from the EARLY study

OBJECTIVE

The primary objective of this study was to determine whether the National Cholesterol Education Program Step II (NCEP-II) diet or supplementation with docosahexaenoic acid (DHA) with the diet, affects endothelial function in children with familial hypercholesterolemia (FH) or the phenotype of familial combined hyperlipidemia (FCH). As secondary endpoints, the influence of diet and DHA supplementation on lipid profiles as well as biomarkers for oxidative stress and inflammation, and asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, were all evaluated.

METHODS

In a double-blind, placebo-controlled, randomized, crossover study design, 20 children (ages 9-19 years) with FH (n = 12) and FCH (n = 8) received nutritional counseling based on the National Cholesterol Education Program Step II (NCEP-II) and food guide pyramid dietary guidelines for 6 weeks. They were then randomly assigned to supplementation with docosahexaenoic acid (DHA 1.2 g/d) or placebo for 6 weeks, followed by a washout phase of 6 weeks and crossover phase of 6 weeks while continuing the NCEP-II diet. Endothelium-dependent flow-mediated dilation (FMD) of the brachial artery was determined by high-resolution ultrasound. Plasma levels of total cholesterol, triglycerides and lipoprotein classes (LDL, HDL, VLDL) were measured by ultracentrifugation and enzymatic methods, plasma F2 isoprostanes by gas chromatography/mass spectrometry, urinary 8-OH-2' deoxyguanosine by liquid chromatography, high sensitivity C-reactive protein by immunonephelometry and ADMA by liquid chromatography.

RESULTS

FMD increased significantly after DHA supplementation compared to baseline (p < 0.001), diet alone (p < 0.002), placebo (p < 0.012) and washout (p < 0.001) phases of the study without affecting biomarkers for oxidative stress, inflammation or ADMA. DHA supplementation was associated with increased levels of total cholesterol (p < 0.01), LDL- and HDL cholesterol concentrations (p < 0.001) compared to the NCEP-II diet.

CONCLUSION

This study demonstrates that DHA supplementation restores endothelial-dependent FMD in hyperlipidemic children. The endothelium may thus be a therapeutic target for DHA. This is consistent with a hypothesis of increasing NO bioavailability, with the potential for preventing the progression of early coronary heart disease in high-risk children.

Antioxidant vitamins C and E improve endothelial function in children with hyperlipidemia: Endothelial Assessment of Risk from Lipids in Youth (EARLY) Trial

BACKGROUND

Hyperlipidemia is associated with endothelial dysfunction, an early event in atherosclerosis and predictor of risk for future coronary artery disease. Epidemiological studies suggest that increased dietary intake of antioxidants reduces the risk of coronary artery disease. The purpose of this study was to determine whether antioxidant vitamin therapy improves endothelial function and affects surrogate biomarkers for oxidative stress and inflammation in hyperlipidemic children.

METHODS AND RESULTS

In a randomized, double-blind, placebo-controlled trial, the effects of antioxidant vitamins C (500 mg/d) and E (400 IU/d) for 6 weeks and the National Cholesterol Education Program Step II (NCEP-II) diet for 6 months on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery were examined in 15 children with familial hypercholesterolemia (FH) or the phenotype of familial combined hyperlipidemia (FCH). Antioxidant vitamin therapy improved FMD of the brachial artery compared with baseline (P<0.001) without an effect on biomarkers for oxidative stress (autoantibodies to epitopes of oxidized LDL, F2-isoprostanes, 8-hydroxy-2'-deoxyguanosine), inflammation (C-reactive protein), or levels of asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide.

CONCLUSIONS

Antioxidant therapy with vitamins C and E restores endothelial function in hyperlipidemic children. Early detection and treatment of endothelial dysfunction in high-risk children may retard the progression of atherosclerosis.

Homocysteine impairs coronary microvascular dilator function in humans

OBJECTIVES

We sought to use positron emission tomography (PET) to test the hypothesis that hyperhomocysteinemia adversely effects coronary microvascular dilator function.

BACKGROUND

Hyperhomocysteinemia is associated with abnormal endothelium-dependent vasodilation in peripheral human arteries. However, its effect on the coronary circulation is not known.

METHODS

Eighteen healthy humans, age 24 to 56 years, were enrolled in a double-blind, crossover trial. Basal and adenosine-stimulated myocardial blood flow (MBF) was determined by PET: after ingestion of placebo and after methionine-induced hyperhomocysteinemia. Further, brachial ultrasonography was used to assess flow-mediated vasodilation. Additionally, to assess the role of nitric oxide (NO) in adenosine-mediated vasodilation, the MBF response to adenosine was measured in the presence and absence of the NO synthase antagonist NG-monomethyl-l-arginine (l-NMMA) (0.3 mg/kg/min intravenously).

RESULTS

Hyperhomocysteinemia resulted in a reduction in the MBF dose-response curve to adenosine (p < 0.05). This was most apparent with low dose adenosine, where MBF augmentation was significantly blunted during hyperhomocysteinemia (1.06 +/- 1.00 ml/min/g vs. 0.58 +/- 0.78 ml/min/g, placebo vs. methionine, p < 0.05). Similarly, flow-mediated brachial artery vasodilation was impaired during hyperhomocysteinemia (4.4 +/- 2.6% vs. 2.6 +/- 2.3%, placebo vs. methionine, p < 0.05). In a separate series of experiments, MBF during adenosine was reduced in the presence of l-NMMA (p < 0.05 analysis of variance). This was most apparent at the low dose of adenosine, where MBF response to adenosine was blunted in the presence of l-NMMA (2.08 +/- 1.34 ml/min/g vs. 1.48 +/- 1.32 ml/min/g, placebo vs. l-NMMA, p < 0.05).

CONCLUSION

The data, therefore, support the hypothesis that acute hyperhomocysteinemia impairs microvascular dilation in the human coronary circulation as a result of reduced NO bioavailability.