Lp(a) is not associated with arterial stiffness: a Mendelian randomization study

Background

Deeper understanding of the potential causal relationship between Lp(a) and vascular injury will provide further insight to related pathways to be monitored and targeted by emerging treatments. Accumulating evidence supports the causal association of lipoprotein(a) [Lp(a)] with cardiovascular disease and calcific aortic valve disease (AVD). Arterial stiffening is mechanistically linked with cardiovascular disease and AVD severity. We hypothesized that Lp(a) may be causally associated with pulse-wave velocity (PWV) as the gold-standard marker of arterial stiffness.

Aim

To investigate the potential causal association of Lp(a) levels with PWV.

Methods

We performed a two sample Mendelian randomization (MR) analysis of LP(a) on PWV by combining the summary data of two independent Genetic-Wide Association Study (GWASs). Genetic variants associated with Lp(a) were retrieved from the UK Biobank (N=220,497). A GWAS based on a cohort in Germany (N=7,000) was used to obtain genetic associations for PWV index (outcome). We assessed two different measures of arterial stiffness, brachial ankle (baPWV) and carotid femoral pulse (cfPWV) wave velocity. In total, we used 170 SNPs as Instrument Variables (IV's) and applied a two sample MR with the main technique of Inverse Variance Weighting method (IVW). We conducted sensitivity analyses (MR-Egger and Median based) to detect pleiotropy of the causal variants and to test for robustness of our findings.

Results

Our analyses based on all 170 SNP's did not find evidence for causal relationship between Lp(a) and PWV for neither measurement [bivw (baPWV) = −0.0005, CI (−0.0043, 0.0034), P=0.8 and bivw (cfPWV) = −0.006, CI (−0.013, 0.002), P=0.16 for brachial ankle and carotid-femoral PWV, respectively]. Sensitivity analyses, including weighted median and mode-based estimation, did not show significant association of Lp (a) with neither baPWV nor cfPWV.

Conclusions

Lp(a) is not causally associated with arterial stiffness. These findings suggest that arterial stiffening is not involved Lp(a)-mediated cardiovascular and aortic valve disease.

Funding Acknowledgement

Type of funding sources: None.

Anatomical variations in coronary venous drainage: challenges and solutions in delivering cardiac resynchronisation therapy

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiac resynchronisation therapy (CRT) is the cornerstone of heart failure management. Delivery of a left ventricular lead can occur in a small proportion of patients undermining the benefits of this treatment. Abnormal coronary venous anatomy is a contributing factor to this failure. Although epicardial lead placement is available, this patient cohort requiring CRT is subject to higher peri-operative morbidity and mortality than the general population; a transvenous approach is preferable.

Purpose

To investigate the abnormalities of the coronary venous system in candidates for cardiac resynchronization therapy (CRT) and describe methods for circumventing the resulting difficulties.

Methods

From 4 implanting institutes, data of all CRT implants between October 2008-October 2020 were screened for abnormal cardiac venous anatomy, defined as an anatomical variation not conforming to the accepted ‘normal’ anatomy. Patient demographics, procedural detail and subsequent left ventricle (LV) lead pacing indices were collected.

Results

From a total of 3548 CRT implants, 15 (0.42%) patients (80% male) of 72.2±10.6 years in age with a LV ejection fraction of 34±10.3% were identified to have had an abnormal cardiac venous anatomy over the study period. There were 13 cases of persistent left side superior vena cava (pLSVC), 5 of which had coronary sinus ostium atresia (CSOA) including 2 with an ‘unroofed’ coronary sinus (CS); 1 patient had a unique anomalous origin of the CS and 1 patient had an isolated CSOA. In total 14 patients (60% repeat attempt) had successful percutaneous implant under general anaesthesia (46.7%) via the cephalic vein (59.1%), using the femoral approach (53.3%) for levophase venography and/or pull-through, including 1 case of endocardial LV implant. Pacing follow-up over 37.64±37.6 months demonstrated LV lead threshold between 0.62-2.9 volts (pulsewidth 0.4-1.5 milliseconds) in all cases; 5 patients died within 2.92±1.6 years of successful implant.

Conclusion

CRT devices can be implanted percutaneously even in the presence of substantial abnormalities of coronary venous anatomy. Alternative routes of venous access may be required.

Transvenous lead extraction: the Tandem approach

Funding Acknowledgements

Type of funding sources: None.

Background

Transvenous lead extraction (TLE) has become an important strategy in the management of patients with cardiac implantable electronic devices (CIEDs). A rising population of patients with CIEDs coupled with an expanding indication for TLE, has fuelled demand. There are notable procedural risks however development of techniques and tools have contributed to an improvement in the safety and efficacy of TLE. The mechanical rotational dissecting sheath is safe and efficacious whilst the Needle’s Eye Snare (NES) is an additional ‘bail-out’ strategy contributing to procedural success.

Purpose

We sought to evaluate the outcomes of TLE performed from the superior access in conjunction with counter-traction provided by snaring of the targeted lead via the femoral access.

Method

The ‘Tandem’ procedure consisted of the rotational powered sheath performing dissection of the adhesions encapsulating the leads (at the superior access), in ‘Tandem’ with the Needle’s Eye Snare providing countertraction via the femoral vein. In brief: after deployment of the locking stylet in the lead lumen, the NES was used to grasp the lead in the right atrium and hold it tort while a rotational sheath was used to dissect through the veins. Once the sheath reached the right atrium, the lead was released from the snare and the sheath was used to continue dissection toward the lead tip. Data for all consecutive ‘Tandem’ procedures performed between 1/1/2021 – 1/1/2022 in our high-volume TLE institute were collected and evaluated for safety and efficacy.

Results

Forty patients aged 69.2±16.3 (70% male), underwent TLE of 75 leads (45 right ventricle, 25, right atrium, 5 left ventricle) with dwell time of 150.1±80.3 months for a non-infectious indication (65%). Of the 40 cases, 27 were hypertensives, 14 had ischaemic heart disease whilst 5 suffered diabetes with a left ventricle ejection fraction of 46.8±10.2%; 12 (30%) were pacing dependent. Procedures were performed by cardiologists in the cardiac catheterisation suite under general anaesthesia (95%) using a locking stylet (100%) with an Evolution RL (11-french 58.7%); a NES 13 millimetres curve (88%) was used to successfully snare 91% of the targeted leads. Complete procedural success was achieved in 92% of leads with 98.7% clinical success. Minor complications occurred in 2 cases (pneumothorax, pocket haematoma requiring intervention), in the absence of any major complications or peri-procedural mortality; there was no 30-day mortality.

Conclusion

The ‘Tandem’ procedure provides an additional strategy to improve the safety and efficacy of TLE, especially in leads of a long dwell time.

Tunnelled dialysis catheter extraction: a cardiology experience

Funding Acknowledgements

Type of funding sources: None.

Background

Tunnelled dialysis catheters are integral to the management of patients with chronic kidney disease (CKD), providing a means to dialysis. They are prone to blockages necessitating removal. Most catheters are removed with manual traction without any sequalae by renal physicians whilst a small proportion require further intervention which may include interventional radiology or an ‘open’ surgical removal which carries additional risk. Cardiologists versed in transvenous lead extraction (TLE) provide an additional strategy.

Purpose

To evaluate the outcomes of tunnelled dialysis catheter ‘extractions’ performed by cardiologists at a high-volume TLE institute.

Method

All consecutive patients referred to cardiologists (1/10/2016 – 1/10/21) for extraction of tunnelled dialysis catheters following an unsuccessful attempt by the renal physicians and interventional radiology, were included in this series. Data of procedural outcomes was evaluated for safety and efficacy.

Results

Twelve patients (7 male) aged 64.15±15.04 years with a body mass index of 28.3 kg/m2 were referred for tunnelled catheter extraction for non-functioning lines (75%). Of these 12 CKD patients, the aetiology included focal segmental glomerulosclerosis (n=2), hypertension (n=2), diabetes (n=1) and sickle cell disease (n=1). In total, 12 tunnelled catheters (75%; n=9 right side) were completely removed (100%) using local anaesthesia (83.3%) in a procedure lasting 54.7±29.8 minutes and requiring 0.79±1.32 minutes of fluoroscopy. Eleven patients (91.7%) had their catheters successfully extracted with manual traction alone; 3 necessitated the use of a 0.035 stiff J-tip wire whilst one required the use of a rotational dissecting sheath Evolution (Cook Medical, USA). Of the 12 cases, 11 had a failed previous attempt including 1 patient who suffered a ventricular fibrillation cardiac arrest during the procedure and 1 was referred directly without an attempt as there was a concurrent pacemaker situated from the contralateral side; 4 patients had new lines placed and no significant complications occurred. There were no complications or procedural mortality.

Conclusion

Extraction of tunnelled dialysis catheter lines performed by cardiologists is safe and efficacious; experience in TLE is vital. This may provide an additional strategy for removal of these catheters when other percutaneous attempts fail.

The effect of per os colchicine administration in combination with fenofibrate and N-acetylcysteine on triglyceride levels and the development of atherosclerotic lesions in cholesterol-fed rabbits

OBJECTIVE

Atherosclerosis is a chronic inflammatory disease promoted by pro-inflammatory cytokines produced by NOD-, LRR- and pyrin domain-containing protein 3 (NLRP 3) inflammasome. Colchicine is an anti-inflammatory agent that inhibits inflammasome's action and stabilizes atherosclerotic lesions. N-acetylcysteine (NAC) reduces low-density lipoprotein (LDL) oxidation, metalloproteinase levels, and foam cell count and volume. Fenofibrate also has antioxidant, anti-inflammatory, and anticoagulant properties while also having a beneficial effect on the vasomotor function of the endothelium. The purpose of this study is to investigate the effect of per os colchicine administration in combination with fenofibrate and NAC on triglyceride levels and the development of atherosclerotic lesions in cholesterol-fed rabbits.

MATERIALS AND METHODS

Twenty-eight male, 2 months old New Zealand White rabbits were separated into four groups and were fed with different types of diet for 7 weeks: standard, cholesterol 1% w/w, cholesterol 1% w/w plus colchicine 2 mg/kg body weight plus 250 mg/kg body weight/day fenofibrate, and cholesterol 1% w/w plus colchicine 2 mg/kg body weight plus 15 mg/kg body weight/day NAC. Blood samples were drawn from all animals. Lipid profiles were assessed, and interleukin 6 (IL-6) measurements were performed using an enzyme-linked immunosorbent assay (ELISA) kit. Histologic examination was performed on aorta specimens stained with eosin and hematoxylin. Aortic intimal thickness was evaluated using image analysis.

RESULTS

Colchicine administration in combination with fenofibrate or NAC statistically significantly reduced the extent of atherosclerotic lesions in aortic preparations. Co-administration of colchicine with NAC has a stronger anti-atherogenic effect than the colchicine plus fenofibrate regimen. Triglerycide levels were decreased in the colchicine plus fenofibrate group and the colchicine plus NAC group at the end of the experiment (p < 0.05), whereas the Cholesterol group had increased levels. A favorable significant lower concentration of IL-6 was detected in the colchicine plus NAC group vs. the other groups.

CONCLUSIONS

In an experimental rabbit model, it appears that colchicine statistically significantly reduces the development of atherosclerosis of the aorta, especially in combination with NAC. Colchicine, as an NLRP3 inflammasome inhibitor, and NAC, as an agent that directly targets IL-6 signaling, can reduce the inflammatory risk. Fenofibrate enhances the attenuating role of colchicine on triglyceride levels. Clinical studies should investigate whether similar effects can be observed in humans.

Anti-Mullerian hormone concentrations are inversely associated with subclinical atherosclerosis in premenopausal women

Background

Anti-Müllerian hormone (AMH) constitutes a marker of ovarian reserve and appears to have a predictive role regarding the time of menopause. Moreover, AMH is associated with adverse cardiac events. History of premature menopause and early onset of menopause have been associated with increased risk of cardiovascular (CV) disease. In addition, menopausal transition and duration of menopause have been associated with increased burden of subclinical atherosclerosis. However, the association between AMH as a marker of female reproductive age with atherosclerosis in premenopausal women is currently unknown.

Purpose

To investigate whether AMH concentrations are associated with markers of early atherosclerosis in healthy, normally menstruating women.

Methods

In a cross-sectional study, vascular structure and function were assessed by measurement of carotid and femoral intima-media thickness (IMT), lipid profile and serum AMH concentrations were assessed. Exclusion criteria were clinically overt CV disease, abnormal ovulatory cycles, polycystic ovarian syndrome, acute infection or chronic inflammatory disease, risk factors for CV disease and any medication

Results

Seventy premenopausal women, aged 32.7±6.5 years, were included. Mean AMH levels were lower in smokers than in non-smokers and negatively associated with total cholesterol (TC) levels. An inverse association between mean AMH concentrations and IMT in all segments was observed. No correlation with other markers of subclinical atherosclerosis or traditional CV risk factors was found. After multi-variable adjustment for traditional CV risk factors, the association between AMH concentrations combined IMT and carotid bulb IMT, remained significant.

Conclusions

In healthy, normally ovulating women, low AMH concentrations are associated with an adverse lipid profile and subclinical atherosclerosis, independently of traditional CV risk factors. This finding suggest a role of decreased follicular reserve with atherosclerotic disease.

Funding Acknowledgement

Type of funding source: None

Intravenous lipid emulsion as an antidote in clinical toxicology: a systematic review

OBJECTIVE

Intravenous lipid emulsions (ILE) were developed many decades ago to supply nutritional requirements to patients unable to obtain adequate enteral nutrition. The utility of ILE was extended to therapeutics, facilitating the delivery of drugs. More recently, the potential for ILE to act as an antidote for inversion of drug toxicity has been recognized. This review aims to summarize the literature on ILE therapy as an antidote. Suggested mechanisms of action, safety profile, and recommendations on the administration of ILE in cases of drug intoxication are highlighted.

MATERIALS AND METHODS

A complete literature survey was performed using the PubMed database search to collect available information regarding mechanisms of ILE action as an antidote, ILE administration for drug toxicity, and presentation of adverse events.

RESULTS

A total of 102 studies met the selection criteria for inclusion in the review. Mainly used for local anesthetics toxicity, ILE therapy has been expanded in clinical toxicology involving overdose treatment of drugs other than local anesthetics. Partitioning in a lipid phase of fat droplets is a mechanism named the lipid sink phenomenon that has primarily been described to explain this action of ILE and remains the most widely accepted. At the same time, recent research has also revealed several molecular mechanisms that may contribute to ILE efficacy.

CONCLUSIONS

ILE therapy comprises a recognized approach in clinical toxicology. Due to the lack of randomized clinical trials, recommendations on administration are based on animal studies and published cases. Thus, the constantly increased knowledge about ILE therapy supports the need for a detailed appraisal.

Cardiac allograft vasculopathy after heart transplantation: current prevention and treatment strategies

OBJECTIVE

Cardiac allograft vasculopathy (CAV) is a leading cause of mortality in heart transplantation patients. Despite optimal immunosuppression therapy, the rate of CAV post-transplantation remains high. In this review, we gathered all recent studies as well as experimental evidence focusing on the prevention and treatment strategies regarding CAV after heart transplantation.

MATERIALS AND METHODS

A complete literature survey was performed using the PubMed database search to gather available information regarding prevention and treatment strategies of CAV after heart transplantation.

RESULTS

Several non-immune and immune factors have been linked to CAV such as ischemic reperfusion injury, metabolic disorders, cytomegalovirus infection, coronary endothelial dysfunction, injury and inflammation respectively. Serial coronary angiography combined with intravascular ultrasound is currently the method of choice for detecting early disease. Biomarkers and noninvasive imaging can also assist in the early identification of CAV. Treatment strategies such as mammalian target of rapamycin inhibitors proceed to grow, but prevention remains the objective.

CONCLUSIONS

Early detection is the key to therapy management. It enables early identification and diagnosis of patients with CAV, who would gain the most from prompt treatment. Further investigation is needed to elucidate the multifactorial pathophysiological process of CAV, develop detection methods and find treatments that prevent or slow disease progression.

P2541Plasma levels of amyloid beta 1-40 are associated with the rate of progression of carotid subclinical atherosclerosis in postmenopausal women

Background

There is increasingly recognized undetected residual cardiovascular (CV) risk in postmenopausal women, suggesting the need for new risk biomarkers in this population. We have previously shown that amyloid-beta (1–40) (Aβ1–40), a proinflammatory and pro-atherosclerotic peptide, is associated with concurrent subclinical cardiovascular disease (CVD) in the general population and with major adverse cardiac events in patients with established cardiac disease. However, the clinical value of Aβ1–40 in menopause or whether this peptide is linked with an increased rate of progression of atherosclerotic disease is unknown.

Purpose

To examine the association of Aβ1–40 levels with the rate of progression of carotid intima-media thickness (IMT) in postmenopausal women.

Methods

In the settings of a Menopause Clinic, postmenopausal women (n=140) without clinically overt CVD or diabetes were consecutively recruited and re-evaluated after a median follow-up period of 24 months. IMT in the carotid arteries was measured by ultrasonography. The average of maximal IMT (mean cIMT) measured at both left and right common carotid, carotid bulb (cb)and internal carotid (ic) artery were used as the main end-point of the analysis. Aβ1–40 was measured in plasma samples at baseline and follow up. Fasting insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR).

Results

Women with increased plasma levels Aβ1–40 in the highest tertile presented the highest probability to have increased mean cIMT (adjusted OR=2.97, 95% CI 1.18–7.52, p=0.021) independently of age, smoke, hypertension, and hyperlipidemia. After adjustment for HOMA-IR, this association remained significant. Similarly, Aβ1–40 levels were associated with increased mean cb and icIMT (adjusted OR=3.34 for highest versus lower tertile, 95% CI 1.27–8.81, p=0.015). Mean cIMT significantly increased across the follow up period (0.73mm (0.065–0.08) to 0.77mm (0.07–0.089), median increase rate per year 0.024mm, p<0.001). By multi-level linear mixed model analysis, changes in Aβ1–40 levels were associated with increased rate of progression of mean cIMT (4.1% increase per 1-SD increase, p<0.001) after adjustment for differences in follow-up duration and age, hypertension, hyperlipidemia, and smoking. When repeated measurements of HOMA-IR were also considered, this association did not materially change (p=0.021). Similarly, longitudinal changes in Aβ1–40 correlated with the progression of mean cb and icIMT (3.9% increase per 1-SD increase, p=0.001), independently of time to re-evaluation and cardiovascular risk factors.

Conclusion

Aβ1–40 is an independent predictor of the rate of progression of subclinical carotid atherosclerosis in menopausal women. This finding supports the clinical value of Aβ1–40 in menopause and warrants further investigation for its prognostic role in this population.

P4492Peripheral blood mononuclear cell expression of the stabilizing RNA-binding protein HuR is associated with incidence and extent of human atherosclerotic cardiovascular disease

Background

Human Antigen R (HuR) is a stabilizing RNA-binding protein that regulates the expression of several pro-inflammatory molecules. However, its regulation in human atherosclerotic cardiovascular disease remains unknown.

Purpose

To determine the association of peripheral blood mononuclear cell HuR expression with established markers of increased cardiovascular risk and atherosclerosis burden in patients with subclinical or clinically overt coronary artery disease (CAD).

Methods

HuR mRNA expression was measured in peripheral blood mononuclear cells derived from 289 patients with stable CAD or acute myocardial infarction (AMI) and 373 individuals without clinically overt cardiovascular disease (CVD). Structural and functional vascular measurements including intima-media thickness (IMT) and number of atheromatous plaques by carotid and femoral artery ultrasonophaphy, markers of arterial wave reflections by pulse wave analysis and pulse wave velocity were used as surrogate markers of subclinical CVD. The number of angiographically confirmed diseased coronary arteries (>50% stenosis) was used to assess the extent of CAD.

Results

HuR mRNA expression was significantly increased in patients with CAD (both stable and AMI) compared to controls (p=0.039). Subgroup analysis revealed that STEMI patients (n=107) had increased levels of HuR expression compared to NSTEMI (n=49, p=0.03). Among patients with stable CAD (n=133), high HuR expression was independently associated with the number of diseased coronary arteries (OR=1.35 for 1-SD increase in HuR, 95% CI 1.07–1.72, p=0.012), as well as with reduced ejection fraction (EF<45%, OR=1.32 per 1-SD increase, 95% CI 1.05–1.85, p=0.024). Among individuals without CVD, high HuR was associated with lower HDL levels (adjusted beta=-5.2 mg/dl for highest versus lowest quartile, p=0.03) and higher diastolic blood pressure (adjusted beta=3.6 mmHg, p=0.007), while, after adjustment for traditional cardiovascular risk factors, HuR levels in individuals without CVD were independently associated with increased IMT in the common carotid artery (mean increase 6.2% for highest versus lowest quartile, p=0.019).

Conclusion

HuR expression is associated with early subclinical arterial disease in individuals without clinically overt CVD and with the presence and severity of cardiac and vascular dysfunction in patients with clinically overt CAD. These findings imply a clinical role of the HuR pathway in cardiovascular disease and warrant further investigation.

Changes in serum leptin levels as well as sICAM-1 and sVCAM-1 soluble adhesion molecules during carotid endarterectomy

OBJECTIVE

Leptin is an adipokine, known to be associated with oxidative stress, inflammation, and atherogenesis. Leptin plays an essential role in atheromatosis-associated inflammatory cascade through stimulation of inflammatory mediators such as soluble intracellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1). However, little is known about this association in patients with atherosclerosis and severe internal carotid artery (ICA) stenosis undergoing carotid endarterectomy (CEA). Our objective was to evaluate the variations of serum leptin levels, as well as sICAM-1 and sVCAM-1 levels in these patients during the process of CEA and 24 hours postoperatively.

PATIENTS AND METHODS

The study group enrolled 50 patients undergoing CEA for ICA stenosis (> 70%). Serum leptin, sICAM-1 and sVCAM-1 plasma concentration measurements were performed at 4 distinct time points: before clamping of the ICA, 30 minutes after clamping of the ICA, 60 minutes after declamping of ICA and 24 hours postoperatively.

RESULTS

Leptin was significantly decreased during CEA, but an overshooting in its levels was observed at 24 hours after the operation. Both sICAM-1 and sVCAM-1 initially followed the pattern of leptin changes but after completing CEA and up to 24 hours postoperatively a steep increase in their levels was not established. sVCAM-1 and sICAM-1 correlated with indices of oxidative stress at peak inflammatory burden.

CONCLUSIONS

Leptin is a circulating marker of carotid atherosclerosis. Oxidative stress and expression of sVCAM-1 and sICAM-1 on vascular endothelial cells are key features in the pathophysiological process of atherosclerosis.

Association of macronutrient consumption with arterial aging in adults without clinically overt cardiovascular disease: a 5-year prospective cohort study

PURPOSE

There is limited and inconsistent evidence regarding longitudinal effects of macronutrients on blood pressure (BP) haemodynamics and arterial aging in populations without cardiovascular disease (CVD). We aimed to prospectively investigate potential association of dietary macronutrients with long-term changes in peripheral and central haemodynamics and arterial stiffness.

METHODS

One hundred and fifteen subjects (46.7 ± 8.73 years, 70 women), free of clinically overt CVD were consecutively recruited. Dietary macronutrient intake was evaluated using 3-day food records at baseline. Aortic stiffness and arterial wave reflections were assessed at baseline and in one follow-up visit 5 years later by pulse wave velocity (PWV) and augmentation index (AI), respectively.

RESULTS

Individuals with the highest consumption of saturated fatty acids (SFA) presented the highest rate of progression in PWV, AI and aortic diastolic BP (p < 0.05 for all) after adjustment for age, gender, smoking, body mass index, hyperlipidemia, insulin resistance, changes in systolic BP and treatment with antihypertensive and hypolipidemic drugs. After similar multivariable adjustments, high consumption of carbohydrates was associated with higher progression of AI, whereas high consumption of monounsaturated fatty acids (MUFA) and fibre with lower progression in aortic and peripheral systolic and diastolic BP (p < 0.05 for all).

CONCLUSIONS

In subjects without CVD, high consumption of SFA is related to accelerated arterial stiffening, while high consumption of MUFA and fibre and low intake of carbohydrates is associated with attenuated progression in blood pressure and arterial wave reflections, respectively. These findings expand current knowledge on the association of macronutrient consumption with arterial aging in the general population.

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas: The PERSEUS experience

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES.