Exploratory proteome profiling in patients with peripartum cardiomyopathy – a biomarker study on the EORP cohort

Background

The diagnosis of peripartum cardiomyopathy (PPCM) remains challenging as heart failure symptoms may also occur during normal pregnancy. This is further aggravated by the absence of biomarkers specific for diagnosis or prognosis of women with PPCM. Indeed, current evidence from the EURObservational Research Programme (EORP) Registry, an ongoing prospective, international, multicentre, observational registry for women with PPCM, report that the time to diagnosis after symptom onset varies from 19.4 to 38.3 days.

Aims

We performed exploratory serum proteome profiling on patients with PPCM, as compared with healthy postpartum mothers, to uncover novel protein biomarkers that would further our understanding of the pathogenesis of the disease and enhance diagnostic evaluation.

Methods

Demographic and clinical data, as well as serum samples were collected from 84 patients with PPCM from seven EORP participating countries and 29 healthy controls (HC) from South Africa. Serum proteomic profiling was conducted using DIA-based label-free quantitative (LFQ) LC-MS at the time of diagnosis from depleted serum samples. Mass spectrometry data were analyzed by Spectronaut v15 using a study-specific spectral library. Proteomic statistical analysis was performed using Perseus version 2.0.3.0 (FDR=0.05; S=0.1).

Results

Patients with PPCM had advanced heart failure (50% had New York Heart Association functional classes III/IV, mean left ventricular ejection fraction [LVEF] of 33.5%±9.3 [vs 57.0±8.8 in HC, p<0.001]). Amongst the 329 proteins that were identified in the serum samples, 17 proteins were significantly differentially upregulated and 18 downregulated in patients with PPCM as compared to the HC (all p<0.05; Figure 1). Adiponectin (log fold change 1.378, p=0.001), pregnancy-specific beta-1-glycoprotein 1 (1.207, p=0.022), disintegrin metalloproteinase domain-containing protein 12 (1.185, p=0.039), peptidyl-prolyl cis-trans isomerase (1.182, p=0.031) and sulfhydryl oxidase 1 (1.101, p=0.004) were among the upregulated proteins, whilst immunoglobulin kappa variable 2–29 (0.856, p=0.029), ficolin-3 (0.898, p=0.001), platelet basic protein (0.917, p=0.006) and thrombospondin-1 (0.930, p=0.043) were among the downregulated. Gene ontology indicated that thrombospondin receptor activity, fibronectin-binding, and vascular endothelial growth factor receptor 2 binding among the most significant regulated molecular functions. The area under the curve (AUC) of the top 10 up-regulated biomarkers ranged from 0.61–0.68 (p<0.05).

Conclusion

Salient biological themes related to immune response proteins, inflammation, fibrosis, angiogenesis, apoptosis, and blood coagulation were identified to be predominant in PPCM versus HC. This indicates the complex pathophysiological mechanisms of PPCM. The newly identified proteins warrant further studies to evaluate their potential use as diagnostic and prognostic markers for PPCM.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): 1. EurObservational Research Programme in conjunction with the Heart Failure Association of the European Society of Cardiology Study Group on Peripartum Cardiomyopathy2. Cape Heart Institute, University of Cape Town, South Africa

Regional disparities in the clinical profiles of patients with peripartum cardiomyopathy in Nigeria: results from the peripartum cardiomyopathy in Nigeria Registry

Background

Peripartum cardiomyopathy (PPCM) seems to have varied epidemiology within and between countries. We recently reported that Kano (North-West Nigeria) has the highest known incidence of PPCM in the world, but the clinical profiles of the patients by regions have not been previously reported. In this study, we aimed to describe the regional differences (if any) in the clinical profiles of patients with PPCM in Nigeria.

Methods

We consecutively recruited 244 PPCM patients over 9 months from 3 hospitals in Kano (n=199; 81.6%) and from 11 hospitals spread across the North-Central, South-West, South-East and South-South zones (n=45; 18.4%) of Nigeria.

Results

The baseline characteristics of the patients are summarised in Table 1. 35 (17.6%) patients in Kano and 10 (23.2%) patients in other zones died (p=0.0523) after a median of 17 months.

Conclusion

PPCM patients in Kano were younger, had lower socio-economic status, presented to hospitals later, were less symptomatic, had larger sizes of cardiac chambers, worse right ventricular systolic function, higher pulmonary artery systolic pressure and were receiving less treatment at enrolment, than those in other zones in Nigeria. This information will be used for advocacy and interactions with healthcare providers.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Dantata Group of Companies (Nigeria). Ammasco International Ltd. (Nigeria). Fortune Oil Mills Nigeria Ltd.

2371Electrocardiographic features and their echocardiographic correlates in peripartum cardiomyopathy based on the EURObservational registry on PPCM

Background

Cardiac disease remains an important cause of maternal morbidity and mortality globally. Peripartum cardiomyopathy (PPCM), defined as heart failure secondary to left ventricular (LV) systolic dysfunction in previously healthy women towards the end of pregnancy or up to five months following delivery, can result in cardiogenic shock due to severe LV dysfunction or arrhythmias leading to sudden cardiac death. Cardiac electrical activity and its relationship to cardiac dysfunction have not yet been interrogated in large multi-centre studies.

Purpose

This study aimed to identify the ECG abnormalities associated with PPCM; their relationship with echocardiographic structural and functional abnormalities and explore regional and ethnic differences in ECG features.

Methods

We included the first 411 patients enrolled into the EURObservational PPCM registry (EORP). Baseline demographic, clinical and echocardiographic data were collected. ECGs were analysed for rate; rhythm; QRS width, axis and morphology; and QTc interval.

Results

Mean age of the women (from >40 countries) was 30.7±6.4 years. More than two thirds of patients presented with NYHA class III or IV (with no regional differences). The median QRS rate was 102bpm (IQR 87–117). More than half presented with sinus tachycardia (QRS rate >100bpm), whereas atrial fibrillation was rare (2.27%). The mean QRS width was 90.1ms ±21.5, with regional differences (ESC 93.8ms ±21.7 vs. non-ESC 86.8ms ±20.8, P<0.001). Left bundle branch block (LBBB) was reported in 9.30% with no regional or ethnic differences. Left ventricular hypertrophy (LVH) was present in a quarter of the cohort, and more prevalent amongst African (59.62%) and Asian (23.17%) than Caucasians (7.63%, P<0.001). The median QTc by Bazett was 456.7ms (IQR 409–490.7) and almost half (47.11%) had prolonged QTc (>460ms). The median LVEDD was 60mm (IQR 55–65) on echocardiography. Compared with their Asian and Caucasian counterparts, African patients were more likely to have LV dilatation (LVEDD>53mm: 70.11%, 79.31% and 89.42% respectively; P=0.004). The median LV ejection fraction (LVEF) was 32.50% (IQR 25–39) with no significant regional or ethnic differences. Sinus tachycardia predicted poor systolic function (OR 1.85 [95% CI 1.20–2.85], p=0.006). LVEF <35% was associated with a significantly higher QRS rate (median rate 107 vs. 98bpm, p=0.002). Women with LVEDD ≥53mm had a longer mean QRS duration (92.0±22.4 vs. 82.4±15.4ms, p<0.001) and frequency of LBBB (11.15% vs 1.54%, p=0.016). LBBB was a predictor of LVEDD >53mm (sensitivity 11.15%; specificity 98.46%; PPV 97.14%; NPV 19.10%; OR 8.02 [95% CI 1.08–59.66], p=0.042).

Conclusion

Patients with PPCM commonly present with sinus tachycardia, LVH, and/or prolonged QTc interval on their ECG. Wide QRS and/or LBBB, were associated with LVEDD>53mm. Sinus tachycardia, however, was associated with LVEF<35%. Risk of arrhythmia in those with prolonged QTc remains to be ascertained.

Acknowledgement/Funding

Heart Failure Association of the ESC