The genetic landscape of mitochondrial diseases in the next-generation sequencing era: a Portuguese cohort study

Introduction: Rare disorders that are genetically and clinically heterogeneous, such as mitochondrial diseases (MDs), have a challenging diagnosis. Nuclear genes codify most proteins involved in mitochondrial biogenesis, despite all mitochondria having their own DNA. The development of next-generation sequencing (NGS) technologies has revolutionized the understanding of many genes involved in the pathogenesis of MDs. In this new genetic era, using the NGS approach, we aimed to identify the genetic etiology for a suspected MD in a cohort of 450 Portuguese patients. Methods: We examined 450 patients using a combined NGS strategy, starting with the analysis of a targeted mitochondrial panel of 213 nuclear genes, and then proceeding to analyze the whole mitochondrial DNA. Results and Discussion: In this study, we identified disease-related variants in 134 (30%) analyzed patients, 88 with nuclear DNA (nDNA) and 46 with mitochondrial DNA (mtDNA) variants, most of them being pediatric patients (66%), of which 77% were identified in nDNA and 23% in mtDNA. The molecular analysis of this cohort revealed 72 already described pathogenic and 20 novel, probably pathogenic, variants, as well as 62 variants of unknown significance. For this cohort of patients with suspected MDs, the use of a customized gene panel provided a molecular diagnosis in a timely and cost-effective manner. Patients who cannot be diagnosed after this initial approach will be further selected for whole-exome sequencing. Conclusion: As a national laboratory for the study and research of MDs, we demonstrated the power of NGS to achieve a molecular etiology, expanding the mutational spectrum and proposing accurate genetic counseling in this group of heterogeneous diseases without therapeutic options.

Impact of coronavirus disease 2019 on adult patients with congenital heart disease

Background

COVID-19 is responsible for a worldwide pandemic, causing more than 18,000 deaths to date in Portugal. Data already exists regarding the increased risk of adverse events in patients with cardiovascular diseases, however the impact of SARS-CoV-2 infection in patients (P) with congenital heart disease (CHD) is still under investigation.

Purpose

To study the impact of COVID-19 in a adult patients with CHD

Methods

Adult patients seen at the CHD outpatient's clinic at a tertiary centre, who became infected with SARS-CoV-2 infection up to December 2021 were included. Assessment of patients' symptoms, need for hospitalization and admission in an intensive care unit was assessed based on medical records.

Results

We identified seventy-nine patients (pts) with COVID-19 infection. Symptoms were present in 67 (84%). The median age was 44 (15) years, 52% were females. Eight P (10%) had complex cyanotic disease; seven Tetralogy of Fallot; five (6%) transposition of great arteries; eight (10%) right ventricle obstacle; two (3%) atrioventricular canal defect; sixteen (20%) atrial septal defect; nine (11%) ventricular septal defect; eight (10%) aortic coarctation; two (3%) had Eisenmenger syndrome. 49% of P had previous surgery or percutaneous procedure. 63% of P were at New York Heart Association (NYHA) class of I and 30% at NYHA II. Mild symptoms were reported by 56 P (71%). Ten adults (7,9%) experienced moderate symptoms (dyspnea and hypoxia) that led to hospitalization for oxygen therapy, none required mechanical ventilation. One death was reported in an 83-year-old patient with non-corrected interventricular communication and compromised biventricular function. There was a significant association between the gravity of CHD and hospitalizations (p=0.02).

Conclusion

Our pts had mainly mild to moderate symptoms and did not appear to have a disproportionately negative outcome; the need for hospitalization was more frequent in patients with higher CHD gravity. These findings are in line with the emerging data regarding COVID-19 in CHD P, and may be in part explained by the patient's young age and functional status.

Funding Acknowledgement

Type of funding sources: None.

3 year outcomes of permanent pacemaker implantation after alcoholic septal ablation

Introduction

Patients with hypertrophic obstructive cardiomyopathy (HOCM) that remain symptomatic despite optimized medical therapy are often submitted to alcohol septal ablation (ASA). One of the most frequent complications is the complete hear block (CHB), requiring permanent pacemaker (PPM) in variable rates, up to 20% of the patients. The long-term impact of PPM implantation in these patients remains unclear.

Objectives

This study aims to evaluate the long-term clinical outcomes in patients who implant PPM after ASA.

Methods

In a tertiary center, patients who underwent ASA were consecutively enrolled prospectively. Patients with previous PPM or implantable cardio-defibrillator were from this analysis. The groups with and without PPM implantation after ASA were compared regarding baseline characteristics, procedure data and 3-year primary and secondary endpoints.

Results

Between 2009 and 2020, 109 patients underwent ASA. 97 patients were included in this analysis (68% female, mean age 65.2 years-old). 16 patients (16.5%) required PPM implantation for CHB. In those, no vascular access, pacemaker pocket or pulmonary parenchyma complications were noted. The baseline characteristics regarding comorbidities, symptoms, echocardiographic and electrocardiographic findings were identical in the two groups, with statistically significant differences in the mean age (70.6y/o in the PPM group versus 64.1y/o) and in the beta-blocker therapy rates previously to the intervention (56% in the PPM group versus 84%). Procedure-related data showed higher creatine kinase (CK) peaks in the PPM group (1692U/L versus 1243U/L, p0.05), without significant differences in the alcohol dose (2.1ml in both groups, p0.33). At 3 years after ASA procedure, the primary endpoint (composite of all-cause mortality and all-cause re-hospitalization) showed a statistical tendency to a lower event rate in the group who implanted PPM (p-value 0.097, Graphic 1). The secondary endpoint (composite of all-cause mortality and cardiac cause re-hospitalization) did not show any significant statistical difference between the two groups (p-value 0.216, Graphic 2).

Conclusions

The long-term endpoint analysis suggests that the outcomes in patients who implant PPM after ASA are non-inferior to those who do not, with a tendency to a lower rate of the endpoint composite of all-cause mortality and all cause re-hospitalizations.

Funding Acknowledgement

Type of funding sources: None.

Fluoroless cavotricuspid isthmus radiofrequency ablation of typical atrial flutter achieves success with zero radiation and shorter procedural duration

Funding Acknowledgements

Type of funding sources: None.

Background

Cavotricuspid isthmus (CTI) ablation in patients with typical atrial flutter (AFL) has improved in the past years, especially by the use of threedimensional (3D) electroanatomic mapping systems. These mapping tools contributed to reduce radiation exposure, but most ablation procedures still require varying amounts of fluoroscopy.

Purpose

We aim to examine whether fluoroless CTI ablation is effective and safe in reducing AFL recurrence, compared with CTI ablation using fluoroscopy and a 3D mapping system.

Methods

A retrospective analysis of CTI ablation procedures performed at a tertiary center between December 2008 and December 2020 was conducted. Cases were divided in two groups: fluoroless and fluoroscopic, according to the use of radiation. Procedural duration, fluoroscopy time (FT), use of 3D mapping system, complications and recurrence rate at one year were analyzed.

Results

A total of 324 CTI ablations performed on patients with documented typical AFL were included. Mean age was 62.3±14.0, with 78.1% male patients. Fluoroless ablations were performed based on a 3D mapping system, and all fluoroscopic procedures also used 3D electroanatomic mapping. The FT was zero in the fluoroless group - 31 cases (9.6%), and 7.0±4.4 minutes in the fluoroscopic group - 291 cases (90.4%) (p<0.001). There was no statistically significant difference between the two groups, regarding AFL recurrence at one year (21.7% in the fluoroless group versus 13% in the fluoroscopic group; odds ratio [OD] 0.54; 95% confidence interval [CI] 0.18-1.62; p=0.27). Total procedure duration was significantly shorter in the fluoroless group (1h07m versus 1h40m; t-test 4.261, p<0.001, CI 0h16m-0h50m). There were no acute complications for both groups.

Conclusion

Fluoroless CTI ablation avoids radiation exposure to the patient and operator and can be performed in patients with typical AFL, without compromising duration, safety or efficacy of the procedure.

Combined pulmonary vein isolation and cavotricuspid isthmus ablation shows no benefit in recurrence of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Background

Pulmonary vein isolation (PVI) is the mainstay of catheter ablation (CA) for atrial fibrillation (AF). Strategies have been proposed to improve the success rate of CA, such as prophylactic cavotricuspid isthmus (CTI) ablation. Despite some studies providing no, or limited, incremental benefit of CTI ablation in patients with AF, it is still frequently performed worldwide.

Purpose

The aim of this study is to examine whether CTI ablation, combined with PVI, is associated with improvement in recurrence of AF, compared with PVI alone in AF patients with or without atrial flutter (AFL).

Methods

We conducted a retrospective analysis of CA for AF performed at a tertiary center between September 2004 and December 2020. The procedures were divided in two groups: "PVI alone" and "PVI plus CTI ablation". Demographic, clinical, and procedure related data was retrieved. Atrial fibrillation recurrence rate at one year was analyzed for both groups and compared using logistic regression.

Results

A total of 453 procedures were analyzed: PVI alone (n=378; 83.4%) and PVI with CTI ablation (n=75; 16.6%). In the PVI alone group, 12.9% of the patients had concomitant typical AFL and in the PVI plus CTI ablation, 45.8% had typical AFL. Mean age was 57.3±12.1 years, with 63.6% male patients. At one year, AF recurrence rate was higher in the combined PVI with CTI ablation group (30.4%; n=21), compared with the PVI alone group (28.4%; n=97), with no statistical difference between the two groups (Odds Ratio [OD] 1.10; 95% confidence interval [CI] 0.62-1.94; p=0.73). In the subgroup analysis, there was no difference in recurrence between patients with AF without AFL (OR: 1.9; 95% CI: 0.39-9.36; p=0.43), and in patients with AF with concomitant AFL (OR: 10.0; 95% CI: 0.9-110.3; p=0.06).

Conclusion

In AF patients, irrespective of the presence of typical AFL, additional CTI ablation, compared with PVI alone, was not associated with improvement in recurrence of AF.

Non-vitamin K antagonist oral anticoagulants in adult congenital heart disease: a single-center study

Introduction

Adults with congenital heart disease (ACHD) are at an increased risk for thromboembolic events and atrial arrhythmias are common in this population. Non-vitamin K anatagonist oral anticoagulants (NOACs) prescription is increasing, however data on efficacy and safety in ACHD is unclear, particularly in patients (P) with complex CHD. The aim of the study was to review the use of NOACs in various types of ACHD and assess its safety and efficacy.

Methods

Evaluation of consecutive ACHD P started on NOAC therapy from 2014 to 2020. P were followed-up for bleeding or thromboembolic events and mortality. CHA2DS2-VASc and HASBLED scores were calculated and risk factors for bleeding were identified.

Results

93 ACHD P were included, mean age 52±15 years, 58% female, 44% with complex CHD (3.2% with Fontan circulation), with diagnosis of: 22.2% atrial septal defect, 20% tetralogy of Fallot, 11.1% transposition of the great arteries, 10% Ebstein's anomaly, 8.9% ventricular septal defect, 7.8% pulmonary stenosis, 5.6% ductus arteriosus, 4.4% AV septal defect, 3.4% univentricular heart, 3.4% coarctation of aorta, 2.2% supra-aortic stenosis and 1% with Uhl disease.

Most P were anticoagulated with rivaroxaban (43%), followed by edoxaban (24%), apixaban (20%), and dabigatran (13%). The indications for anticoagulation were: atrial arrhythmias (81%), pulmonary embolism (PE) (6.3%), atrial thrombi (4.3%), thromboprophylaxis in Fontan circulation (3.2%), deep vein thrombosis (3.2%) and stroke (2%). 66% of P had a CHA2DS2-VASc score ≥2 and 82% HASBLED score ≤2.

In a mean follow-up of 41±21 months (400.4 patient-years), there were embolic events in 2P (1 splenic infarction and 1 PE) albeit both were in the context of oral anticoagulation interruption. The cardiovascular mortality was 2% and allcause mortality 5%, however with no relation to thrombosis or bleeding events.

6 P (6.5%) suffered a minor and 3 P (3.2%) suffered a major bleeding, a median time of 12 (IQR 15) months after starting NOAC therapy. The annual risk for bleeding was 2.2%/patient/year. P with bleeding events showed no significant difference regarding age (55±16 vs 52±15 years, p=0.587), gender (13% female vs 5.1% male, p=0.295) or CHD type (p=0.582). 8.6% of P required dose reduction, mostly for bleeding (3.2%) or renal impairment (2.2%).

Renal disease was a strong risk factor for major bleeding (HR 14.6 [95% CI 1.23–73.6], p=0.033 and multivariate analysis showed that an increased HASBLED score was an independent predictor of minor (adjusted HR 3.44 [95% CI 1.13–10.52], p=0.030) and major (adjusted HR 5.29 [95% CI 1.14–24.45], p=0.033) bleeding complications.

Conclusion

Anticoagulation with NOACs is a safe and effective option for selected ACHD P, although bleeding complications were not negligible, particularly in P with renal disease. Larger scale research studies are required, especially regarding complex CHD such as P with Fontan circulation.

Funding Acknowledgement

Type of funding sources: None.

Virtual fractional flow reserve derived from coronary angiography – artery and lesion specific correlations

Introduction

Virtual Fractional flow reserve (vFFR) from standard non-hyperaemic invasive coronary angiography (ICA) has emerged as a promising non-invasive test to assess hemodynamic severity of coronary artery disease (CAD).

Purpose

To investigate the difference in vFFR analysis between vessels and specific lesions.

Methods

Retrospective analysis of consecutive patients (pts) who underwent invasive functional assessment (iFA) in a tertiary center between 2019 and 2020. vFFR was calculated using dedicated software (CAAS Workstation 8.4) based on coronary angiograms of the acquired in ≥2 different projections, by operators blinded to iFA results. Diagnostic performance of vFFR was evaluated and correlated with iFA, according to coronary vessel, vessel diameter at stenosis, diameter stenosis and area stenosis at lesion. vFFR was considered positive when <0.80. FFR <0.8 and iFR/RFR <0.90 were classified as positive according to current clinical standards.

Results

106 coronary arteries of 95 pts (78% male, mean age 67.8±9.7 years) underwent vFFR evaluation. ICA indications were chronic coronary syndrome in 63% or acute coronary syndrome (non-culprit lesion) in the remaining pts. VFFR accuracy was good (AUC 0.839 (p<0.001) and Pearson's correlation coefficient 0.533 (p<0.001) when vFFR was measured in the distal vessel segment. The correlation improved when vFFR were assessed at lesion site (r=0.631, p<0.001) or up to 1cm below the stenosis (0.610, p<0.001). Binary concordance of 89% were observed in RCA and LAD (Sensibility -S 68%, Specificity-Sp 96%, False positive -FP 3.8%, False negative - FN 31%, predictive positive value-PPV 87%, predictive negative value- PNV 89%), while in the circumflex coronary artery binary concordance were of 77% (S 50%; Sp 82%; FP 18%; FN 50%; PPV 33% and PNV 90%). Correlation between vFFR and iFA was higher in vessels ≥2mm (r=0.730, p<0.001). and in lesions in the extremes of the severity spectrum (Table 1).

Conclusion

vFFR has a moderate to high linear correlation to iFA, depending on the artery and type of lesion studied. The higher correlation was found when vFFR were measured at lesion site, in non-circumflex artery stenosis, in vessels ≥2mm and in vessels with mild or severe stenosis.

Funding Acknowledgement

Type of funding sources: None.

Familial hypercholesterolemia in acute coronary syndrome patients: underdiagnosis in female and in young patients

Introduction

Familial hypercholesterolemia (FH) is often underdiagnosed, particularly in female patients (P), even during hospital admission for acute coronary syndromes (ACS). The aim of this study was to apply the Dutch Lipid Clinic Network (DLCN) Criteria in P admitted for ACS and evaluate gender and age differences.

Methods

Prospective evaluation of P with ACS admitted to a tertiary center from 2005 to 2019. Data including family history and laboratory tests was analysed for the application of the DLCN criteria and results were stratified according to ACS subtype, gender and age groups (20–39, 40–59, 60–79 and ≥80 years [y]). P were followed up for 30 days for hospitalization, recurring ACS and mortality.

Results

3811 P were evaluated, mean age 63±13 years, 28% female and mean LDL cholesterol of 125±43 mg/dL. The admission diagnosis was unstable angina (UA) in 5%, non-ST-segment elevation myocardial infarction (NSTEMI) in 27% and ST-segment elevation MI (STEMI) in 68%.

Applying the DLCN criteria, 3089 P (81%) had a score of <3 (unlikely FH), 675P (17.7%) a score of 3 to 5 (possible FH), 41P (1.1%) a score of 6 to 8 (probable FH) and 1P (0.03%) a score of >8 (definite FH). Stratifying according to ACS type: among UA, 31P (16%) had possible FH and 4P (2.1%) had probable FH. Among NSTEMI, 145P (14.2%) had possible FH, 9P (0.9%) probable FH and 1P (0.03%) definite FH. Finally, among STEMI P, 497P (19.1%) had possible FH and 28P (1.1%) probable FH. Regarding female P, 158P (14.7%) had possible FH and 16 P (1.5%) probable FH. Among male P, 517P (18.9%) had possible FH and 25P (0.9%) probable FH (p=0.016 for interaction).

According to age groups, among P aged 20–39 y (136P), 61P (44.9%) had possible FH and 6P (4.4%) had probable FH. Concerning P aged 40–59 y (1766P), 575P (32.6%) had possible FH, 31 P (1.8%) probable FH and 1P (0.1%) definite FH. With regard to P aged 60–80 y (2122P), 80P (3.8%) had possible FH and 4P (0.2%) probable FH. Among P aged ≥80 y (1837P), only 9P (0.5%) had possible FH and no P had probable FH.

In a 30-day follow-up, there was an hospitalization rate of 3.5% (134P) and recurring ACS in 1.7% (65P), while the all-cause mortality was 2% (78P) and cardiovascular (CV) death was 1.3% (49P). Female P had a significantly lower hospitalization rate (1.8% vs 3.2%, p=0.003) as well as fewer recurring ACS (0.6% vs 1.7%, p=0.001). There was no significant gender difference regarding all-cause mortality (female 1.7% vs 1.5%, p=0.552) or CV death (0.8% vs 1.1%, p=0.323). The DLCN criteria score was significantly correlated with admission for recurring ACS (OR 1.19 [95% CI 1.04–1.36], p=0.04).

Conclusion

Application of the DLCN criteria in female P admitted for ACS revealed 158P (14.7%) with possible FH and 16P (1.5%) with probable FH. Regarding younger ACS P (20–39y), 44.9% had criteria for possible FH and 4.4% for probable FH, prompting us to do not overlook these P subgroups in daily practice and routinely assess the likelihood of FH.

Funding Acknowledgement

Type of funding sources: None.

Transesophageal echocardiography versus intracardiac echocardiography-guided left atrial appendage occlusion: a comparative analysis

Introduction

The left atrial appendage occlusion (LAAO) procedure is a therapeutic option for stroke prevention in patients with atrial fibrillation (AF) which have contraindication to oral anticoagulants or still develop embolic events despite therapeutic anticoagulation. Transesophageal echocardiography (TEE) has been the gold standard to guide this procedure, with the intracardiac echocardiography (ICE) emerging as an alternative because of the advantage of reducing the general anesthesia burden compared to TEE.

Objectives

This study aims to compare the safety, procedure-related parameters and outcomes between TEE-guided LAAO and ICE-guided LAAO.

Methods

In a tertiary center, patients who underwent TEE-guided LAAO and ICE-guided LAAO were compared retrospectively regarding technical success, procedure-related events, procedure-related parameters (fluoroscopy time, dose of radiation and contrast volume), 45 days-transthoracic echocardiography (TTE) and 1-year outcomes (mortality, stroke and major bleeding).

Results

88 patients underwent LAAO between 2009 and 2020 (n=43 with TEE, n=45 with ICE). Baseline characteristics were similar. Success was achieved in 95.3% (n=41) and 95.6% (n=43) of the patients in the TEE and ICE groups, respectively (OR 0.95, p=0.96). Procedure-related complications (major vascular complications, perforation, device embolization) didn't show significant differences (14.0% vs 8.9%, OR 1.66, p=0.46) in the TEE and ICE groups, respectively. Fluoroscopy time was inferior in the TEE group (29.1±13.6 vs 44.1±17.4 minutes, p=0.001), while radiation dose (2761±1555 vs 3397±2118 mGy, p=0.113) and contrast volume (220.3±104.1 vs 204.0±100.9mL, p=0.469) showed no significant differences. 45 days-TTE showed no significant differences between the TEE and ICE groups regarding peri-device leaks (14.0% vs 24.4%, p=0.212), device thrombus (2.3% vs 0%, p=0.990) and iatrogenic atrial septal defects, all mild (4.7% vs 13.3%, p=0.174). 1-year outcomes showed no significant differences regarding stroke (9.3% vs 4.4%, p=0.186), major bleeding (9.3% vs 2.2%, p=0.78) and all-cause mortality (9.3% vs 11.1%, p=0.38) between the TEE and ICE groups, respectively.

Conclusions

ICE-guided LAAO is associated with similar results, procedure-related events, procedure related-parameters (fluoroscopy time being the only exception) and 1-year outcomes, compared with TEE-guided LAAO.

Funding Acknowledgement

Type of funding sources: None.

Anaemia in pregnancy: associations with parity, abortions and child spacing in primary healthcare clinic attendees in Trinidad and Tobago

OBJECTIVE

To determine the prevalence of anaemia in antenatal clinic attendees; to investigate the effects of parity, age, gravidity, previous abortions, child spacing and other factors on the prevalence of anaemia in pregnancy.

METHODS

This was a retrospective and cross-sectional study. Antenatal records of 2287 pregnant women attending 40 public healthcare centres from January 2000 to December 2005 in Trinidad and Tobago were used. Data pertaining to the investigated variables were recorded. The national prevalence of anaemia was calculated and chi-square tests, odds ratios and logistic regression were used to assess the relationship between anaemia and each variable.

RESULTS

The prevalence of anaemia was 15.3% (95% CI 13.4%, 16.6%). No significant difference in the prevalence of anaemia was found among the different clinics or counties. At the first haemoglobin reading, age was inversely related to the presence of anaemia, whereas gestational age at first visit was directly related. At the final haemoglobin reading, parity, gravidity, and previous spontaneous abortions were directly related to the prevalence of anaemia, while the number of visits was inversely related. Age was inversely associated to the severity of anaemia while gravidity was directly related.

CONCLUSION

The prevalence of anaemia decreased by 18.7% from 1967. Despite this positive indication, women under 24 years and those commencing antenatal care after the first trimester are still at a higher risk for developing anaemia. Early commencement of antenatal care and close monitoring of the risk groups identified should be strongly advocated.