Gergana Petrova Voynova

Dr. Gergana Petrova Voynova

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Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 June 2025 in Biomedicines
Verified
Journal Article
Open access
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PKPetar Kalaydzhiev
Petar Kalaydzhiev
Tsvetelina VelikovaTsvetelina Velikova
Tsvetelina Velikova
YDYanitsa Davidkova
Yanitsa Davidkova
GVGergana Petrova Voynova
Gergana Petrova Voynova
ABAngelina Borizanova
Angelina Borizanova
AGAssen Goudev
Assen Goudev
Background: Sleep-disordered breathing (SDB), particularly Cheyne–Stokes respiration (CSR), is highly prevalent among patients hospitalized with acute decompensated heart failure (ADHF) and is associated with worse clinical outcomes. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have demonstrated cardiorenal benefits in heart failure, but their effects on nocturnal respiratory parameters remain underexplored. Objectives: This study aims to evaluate the impact of SGLT2i therapy on key respiratory and cardiac indices including CSR burden, oxygenation, and right heart function in patients with ADHF and reduced left ventricular ejection fraction. Methods: In this single-center prospective cohort study, 60 patients with ADHF, LVEF < 40%, and a baseline apnea–hypopnea index (AHI) > 5 were assessed before and three months after the initiation of SGLT2i therapy. Sleep respiratory parameters were measured using home polygraphy (ApneaLinkTM), while cardiac and renal indices were evaluated by echocardiography, NT-proBNP, and the estimated glomerular filtration rate (eGFR). Structural and functional echocardiographic changes were analyzed both at baseline and following the 3-month treatment period. Patient-reported outcomes were assessed using the Epworth Sleepiness Scale (ESS) and Kansas City Cardiomyopathy Questionnaire (KCCQ). Results: After 3 months of SGLT2i therapy, significant improvements were observed in daytime sleepiness (ESS: −2.68 points; p < 0.001), CSR index (−5.63 events/h; p < 0.001), AHI (−3.07 events/h; p < 0.001), ODI (−6.11 events/h; p < 0.001), and mean nocturnal SpO2 (+1.95%; p < 0.001). KCCQ scores increased by 9.16 points (p < 0.001), indicating improved quality of life. Cardiac assessments revealed reductions in NT-proBNP (−329.6 pg/mL; p < 0.001) and E/e′ ratio (−1.08; p < 0.001), with no significant change in LVEF or chamber dimensions. Right ventricular function improved, as evidenced by the increased TAPSE/sPAP ratio (+0.018; p < 0.001). Renal function remained stable, with a non-significant upward trend in eGFR. Conclusions: This exploratory study suggests that SGLT2 inhibitors may be associated with the attenuation of Cheyne–Stokes respiration and an improvement in right heart function in patients with ADHF, warranting further investigation in controlled trials. These findings highlight the potential of SGLT2is to address overlapping cardio-respiratory dysfunction in this high-risk population.

24 September 2024 in Journal of Clinical Medicine
Verified
Journal Article
Open access
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PKPetar Kalaydzhiev
Petar Kalaydzhiev
ABAngelina Borizanova
Angelina Borizanova
NGNeli Georgieva
Neli Georgieva
GVGergana Petrova Voynova
Gergana Petrova Voynova
SYSlavi Yakov
Slavi Yakov
AGAssen Goudev
Assen Goudev
Background: Acute decompensated heart failure (ADHF) is a condition with a high frequency of hospitalizations and mortality, and obstructive sleep apnea (OSA) is a common comorbidity. Continuous positive airway pressure (CPAP) therapy at home can be a good adjunctive non-drug therapy for these patients. Methods: We conducted a single-center, prospective cohort study from 150 consecutive patients hospitalized for heart failure exacerbation in the cardiology department. Of these, 57 patients had obstructive sleep apnea. After discharge, CPAP therapy at home was offered. We divided them into two groups and followed them for 1 year. All patients received optimal medical treatment. At the end of the period, patients underwent a follow-up physical examination, a follow-up echocardiography, and a follow-up evaluation of the Epworth Sleepiness Scale (ESS). Results: From 81 patients with sleep apnea, 72.8% (n = 59) had obstructive sleep apnea (OSA) and 27.2% (n = 22) had central sleep apnea (CSA). There was a statistically significant difference in body mass index (BMI), ESS, systolic blood pressure (SBP), diastolic blood pressure (DBP), and left ventricular ejection fraction (LVEF%) in the group with CPAP therapy compared to the no-CPAP group. The CPAP group had a median survival of 11.7 months vs. 10.1 months in the no-CPAP group (log-rank (Mantel–Cox) p = 0.044). Conclusions: This study suggests that obstructive sleep apnea is a common comorbidity in patients with acute decompensated heart failure. The addition of CPAP therapy in these patients improves the symptoms and the prognosis.

16 September 2025 in Pharmacia
Verified
Journal Article
Open access
PDF file
PKPetar Kalaydzhiev
Petar Kalaydzhiev
Tsvetelina VelikovaTsvetelina Velikova
Tsvetelina Velikova
GVGergana Petrova Voynova
Gergana Petrova Voynova
RIRadostina Ilieva
Radostina Ilieva
NSNatalia Spasova
Natalia Spasova
AGAssen Goudev
Assen Goudev
This prospective cohort study explored the cardiometabolic, sleep-related, and biomarker effects of glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium–glucose cotransporter-2 inhibitors (SGLT2i), and their combination in patients with heart failure with preserved ejection fraction (HFpEF), type 2 diabetes mellitus (T2DM), obesity, and obstructive sleep apnea (OSA). The findings revealed that therapies including GLP-1RA – either alone or in combination – consistently improved sleep apnea severity, inflammatory and glycemic biomarkers, and right ventricular–pulmonary arterial coupling. In contrast, SGLT2i monotherapy had modest effects in these domains. Notably, the addition of SGLT2i to GLP-1RA did not yield substantial additive benefits regarding sleep-related or inflammatory parameters, suggesting a dominant role of GLP-1RA. These results underscore the clinical relevance of GLP-1RA-based therapies in patients with multimorbid cardiometabolic conditions, particularly in targeting systemic inflammation and obstructive sleep apnea, both of which are critical yet often overlooked contributors to adverse outcomes in HFpEF.

11 December 2024 in Bulgarian Cardiology
Verified
Journal Article
Open access
GVGergana Petrova Voynova
Gergana Petrova Voynova
PKPetar Kalaydzhiev
Petar Kalaydzhiev
RIR. Ilieva
R. Ilieva
GNG. Nikolova
G. Nikolova
DMD. Markov
D. Markov
AGA. Goudev
A. Goudev
The individual approach in the treatment of heart failure (HF) and personalized medicine have been the main topic in recent years in all scientific forums. The combination of chronic obstructive pulmonary disease (COPD) and sleep apnea (SA) further complicates the clinical presentation in patients with HF. The overlap of all three diseases requires a team of specialists and additional therapeutic approach for better control and to improve the prognosis. A large number of the pathophysiological mechanisms of the three diseases also overlap. The novel therapies for HF have shown good results, both in COPD and CA subgroups. Noninvasive ventilation during hospitalization and at home is an established method in the individual groups. In a combination of the three diseases, definitive data from randomized trials are still lacking.

31 December 2024 in Bulgarian Cardiology
Verified
Journal Article
Open access
PDF file
PKPetar Kalaydzhiev
Petar Kalaydzhiev
RIRadostina Ilieva
Radostina Ilieva
NGN. Georgieva
N. Georgieva
SYS. Yakov
S. Yakov
DSDesislava Somleva
Desislava Somleva
ГВГ. Войнова
Г. Войнова
Background: Acute decompensated heart failure (ADHF) is often associated with central sleep apnea (CSA), which exacerbates cardiovascular strain and impacts quality of life. In ADHF patients, CSA contributes to recurrent nocturnal oxygen desaturation, elevated apnea-hypopnea index (AHI), and frequent Cheyne-Stokes respiration episodes, increasing health risks. Echocardiographic monitoring is essential in these patients, providing reliable assessment of heart function over time. Sodium-glucose cotransporter-2 inhibitors (SGLT2i), initially developed for diabetes management, have shown benefi ts for renal function, sleep apnea symptoms, and heart failure outcomes, suggesting potential for multifaceted treatment. Purpose: To evaluate the effects of SGLT2i therapy on echocardiographic parameters and sleep apnea severity in patients with CSA and ADHF with reduced systolic function (HFrEF). Material and methods: We conducted a prospective cohort study with 162 patients, including those with an ejection fraction < 40%, NT-proBNP > 900 pg/ml, and AHIcentral > 5. Exclusions were patients with end-stage renal disease, NYHA class IV heart failure, COPD, or severe respiratory failure. ApneaLink™ and echocardiograms were used for assessments, and patients were followed for three months post-initiation of SGLT2i. Results: Among the 52 eligible patients, 48 completed the study. Echocardiographic improvements were signifi cant, particularly in diastolic function with a reduction in the E/e’ ratio (from 14.74 ± 2.57 to 13.64 ± 2.18, p = 0.002) and right heart function, as shown by decreases in RVOT (from 39.25 ± 4.01 to 38.32 ± 3.59, p = 0.004) and s-PAP (from 41.26 ± 5.74 to 40.07 ± 5.20, p = 0.001). TAPSE also improved (from 18.37 ± 2.17 mm to 18.87 ± 1.96 mm, p < 0.001), and the s-PAP/TAPSE ratio refl ected better right heart effi ciency (from 0.46 ± 0.11 to 0.48 ± 0.10, p < 0.001). Sleep apnea metrics also showed improvement, with reductions in AHI (from 21.35 ± 4.91 to 18.33 ± 4.75, p = 0.015), central AHI (from 13.16 ± 3.70 to 10.04 ± 3.57, p < 0.001), and Cheyne-Stokes respiration episodes (from 33.70 ± 11.20 to 26.58 ± 9.95, p < 0.001). Oxygen desaturation index (ODI) decreased (from 24.29 ± 7.01 to 17.91 ± 5.90, p < 0.001), and NT-proBNP levels, indicating heart failure severity, were reduced (from 1574.89 ± 652.80 pg/ml to 1250.35 ± 484.26 pg/ml, p < 0.001). Conclusion: SGLT2i therapy led to substantial improvements in echocardiographic measures of diastolic and right heart function, along with signifi cant reductions in CSA severity and oxygen desaturation in ADHF patients. These fi ndings support the potential of SGLT2i as an effective treatment option, meriting further study for long-term benefi ts on cardiac and respiratory health.

Verified
Journal Article
Open access
PDF file
PKPetar Kalaydzhiev
Petar Kalaydzhiev
Tsvetelina VelikovaTsvetelina Velikova
Tsvetelina Velikova
GVGergana Petrova Voynova
Gergana Petrova Voynova
DSDesislava Somleva
Desislava Somleva
NSNatalia Spasova
Natalia Spasova
AGAssen Goudev
Assen Goudev
Background: Managing acute decompensated heart failure (ADHF) is complex, particularly when combined with comorbidities like sleep apnea. Effective treatment requires personalized approaches, focusing on quality of life (QoL) and mental health outcomes. Purpose: This study explored the prevalence and characteristics of sleep apnea in patients with obesity and AHF exacerbations. It assessed how different sleep apnea phenotypes impact QoL and mental health, applying personalized medicine strategies. Methods: A prospective cohort study was conducted on 150 patients admitted for AHF exacerbation. Inclusion criteria included an Apnea–Hypopnea Index (AHI) > 5, an Epworth Sleepiness Scale (ESS) > 8, NT-proBNP > 900 pg/mL and informed consent obtained prior to participation. Optimized medical treatment was provided. QoL and mental health were evaluated using the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the Beck Depression Inventory (BDI). Results: Among 81 patients with sleep apnea, 73% (n = 59) had obstructive sleep apnea (OSA) and 27% (n = 19) had central sleep apnea (CSA). OSA patients reported a higher QoL (61.12 ± 17.88) compared to CSA patients (37.18 ± 19.98, p < 0.001). CSA patients exhibited more severe depression (BDI: 26.18 ± 5.5 vs. 16.64 ± 4.1, p < 0.001). Significant correlations were noted between KCCQ and BDI scores (r = −0.849, p < 0.001) and central apnea events (r = −0.485, p < 0.001). Conclusions: Sleep apnea is common in ADHF patients, with CSA being linked to poorer QoL and greater depression. Personalized medicine offers promising strategies to enhance care and outcomes.