Özkan Karaca

Dr. Özkan Karaca


Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

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

Representative Publications

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11 October 2021 in Symmetry
Verified
Journal Article
Open access
PDF file
MKMehmet Ali KOBAT
Mehmet Ali KOBAT
ÖKÖzkan Karaca
Özkan Karaca
Prabal Datta BaruaPrabal Datta Barua
Prabal Datta Barua
Sengul DoganSengul Dogan
Sengul Dogan
Background and objective: Arrhythmia is a widely seen cardiologic ailment worldwide, and is diagnosed using electrocardiogram (ECG) signals. The ECG signals can be translated manually by human experts, but can also be scheduled to be carried out automatically by some agents. To easily diagnose arrhythmia, an intelligent assistant can be used. Machine learning-based automatic arrhythmia detection models have been proposed to create an intelligent assistant. Materials and Methods: In this work, we have used an ECG dataset. This dataset contains 1000 ECG signals with 17 categories. A new hand-modeled learning network is developed on this dataset, and this model uses a 3D shape (prismatoid) to create textural features. Moreover, a tunable Q wavelet transform with low oscillatory parameters and a statistical feature extractor has been applied to extract features at both low and high levels. The suggested prismatoid pattern and statistical feature extractor create features from 53 sub-bands. A neighborhood component analysis has been used to choose the most discriminative features. Two classifiers, k nearest neighbor (kNN) and support vector machine (SVM), were used to classify the selected top features with 10-fold cross-validation. Results: The calculated best accuracy rate of the proposed model is equal to 97.30% using the SVM classifier. Conclusion: The computed results clearly indicate the success of the proposed prismatoid pattern-based model.

20 June 2026 in Nutrients
Verified
Journal Article
Open access
PDF file
BTBurak Toprak
Burak Toprak
NSNihat Söylemez
Nihat Söylemez
MSMENAF AKIN SERT
MENAF AKIN SERT
ÖKÖzkan Karaca
Özkan Karaca
MEMustafa Ekici
Mustafa Ekici
RBRIDVAN BORA
RIDVAN BORA
Background: Coronary anatomical complexity is commonly used for perioperative risk assessment in patients undergoing coronary artery bypass grafting (CABG), although it may not fully reflect systemic biological vulnerability. This study aimed to evaluate the association between the Prognostic Nutritional Index (PNI), a nutritional–immune marker derived from serum albumin and lymphocyte counts, and in-hospital mortality after CABG in relation to coronary anatomical complexity and established surgical risk scores. Methods: In this single-center retrospective cohort study, 324 consecutive patients who underwent isolated CABG between April 2024 and April 2025 were analyzed. The PNI was calculated according to the standard Onodera formula using preoperative serum albumin and total lymphocyte count. Associations with in-hospital mortality were evaluated using univariable and multivariable logistic regression analyses. Discriminative performance was assessed using receiver operating characteristic curve analysis, while exploratory analyses evaluating the additional prognostic contribution of the PNI beyond surgical risk scores were performed using nested model comparison and reclassification analyses. Internal validation and calibration analyses were also performed. Results: In-hospital mortality occurred in 26 patients. Preoperative and postoperative PNI values were significantly lower in patients who experienced in-hospital mortality. In multivariable analysis, the postoperative PNI remained independently associated with in-hospital mortality, whereas the preoperative PNI lost statistical significance after adjustment for clinical, renal, and surgical risk parameters. Receiver operating characteristic analysis demonstrated modest discriminative ability for the preoperative PNI (AUC: 0.742, 95% CI: 0.661–0.823). Exploratory analyses suggested a modest improvement in model discrimination and risk classification after the addition of the PNI to STS-based models; however, the overall incremental prognostic contribution remained limited. Calibration and internal validation analyses demonstrated acceptable agreement between predicted and observed mortality risk. Conclusions: The postoperative PNI demonstrated a stronger and independent association with in-hospital mortality than the preoperative PNI, suggesting that early postoperative nutritional–immune deterioration may reflect the magnitude of perioperative physiological stress and evolving clinical deterioration after CABG. Although lower preoperative PNI values were associated with mortality in univariable analyses, this association was no longer statistically significant after adjustment for clinical, renal, and surgical risk parameters. These findings indicate that postoperative nutritional–immune status may provide complementary biological information beyond conventional risk models; however, its clinical utility requires confirmation in larger prospective multicenter studies.

2 February 2026 in European Heart Journal - Case Reports
Verified
Journal Article
Open access
SYSamet Yılmaz Yılmaz
Samet Yılmaz Yılmaz
ZBZiya Gökalp Bilgel
Ziya Gökalp Bilgel
ÖKÖzkan Karaca
Özkan Karaca
NSNihat Söylemez
Nihat Söylemez
MBMehmet Ballı
Mehmet Ballı
ATAbdullah Tekin
Abdullah Tekin
Background: ST-elevation myocardial infarction (STEMI) is most commonly caused by atherosclerotic coronary artery occlusion. In some instances, non-atherosclerotic mechanisms should also be considered. We present a case of a floating thrombus in the aortic root moving in and out of the right coronary ostium, leading to STEMI. Case summary: A 70-year-old man with stage IIIA lung adenocarcinoma receiving ongoing chemotherapy presented with syncope. The ECG revealed ST-segment elevation in the inferior leads and intermittent complete atrioventricular block with a heart rate of 40 bpm. A temporary transjugular pacemaker was inserted because of haemodynamic instability. Coronary angiography showed patent coronary arteries but cyclic radiolucency at the right coronary artery (RCA) ostium during RCA injections. Transoesophageal echocardiography identified a 2.5–3.0 cm pedunculated, mobile mass consistent with thrombus attached to the right coronary sinus, intermittently prolapsing into the RCA ostium. Surgical thrombectomy or fibrinolysis was deemed high risk because of prior thoracic radiotherapy and active malignancy with cranial metastases. A pre-emptive RCA guidewire was placed, and the thrombus obstructing the RCA ostium was successfully removed with multiple-pass aspiration using a 10F PRONTO.035 extraction catheter, achieving TIMI 3 flow. Haemodynamic status and rhythm improved subsequently. The patient was discharged on apixaban. Discussion: This case illustrates dynamic RCA obstruction caused by an aortic root thrombus managed with catheter-based aspiration. However, this approach should be considered on a case-by-case basis, given its high thromboembolic potential.

8 June 2025 in Catheterization and Cardiovascular Interventions
Verified
Journal Article
Closed access
SSSefa SURAL
Sefa SURAL
MDMehmet Ercüment Döğen
Mehmet Ercüment Döğen
BDBaris Duzel
Baris Duzel
ÖKÖzkan Karaca
Özkan Karaca
EBEmmanouil Brilakis
Emmanouil Brilakis
SGSevket Gorgulu
Sevket Gorgulu

25 March 2020 in Journal of Cardiology and Cardiovascular Medicine
Verified
Journal Article
Open access
PDF file
ÖKÖzkan Karaca
Özkan Karaca
KMKarasu Mehdi
Karasu Mehdi
KAKobat Mehmet A
Kobat Mehmet A
KTKIVRAK Tarık
KIVRAK Tarık
Dual antiplatelet therapy (DAPT) combining aspirin and a P2Y12 receptor inhibitor has been consistently shown to reduce recurrent major adverse cardiovascular events (MACE) in patients with acute coronary syndrome (ACS) or undergoing percutaneous coronary intervention (PCI) for stable coronary artery disease (CAD) compared with aspirin monotherapy but at the expense of an increased risk of significant bleeding. Among patients with stable CAD undergoing PCI with drug-eluting stents (DES), shorter duration of DAPT (3–6 months) were shown non-inferior to 12 or 24 months duration concerning MACE but reduced the rates of major bleeding? Contrariwise, prolonged DAPT durations (18–48 months) reduced the incidence of myocardial infarction and stent thrombosis, but at the cost of an increased risk of majör bleeding and all-cause mortality. Until more evidence becomes available, the choice of optimal DAPT regimen and duration for patients with CAD requires a tailored approach based on the patient clinical presentation, baseline risk profile and management strategy. Patients with acute coronary syndromes (ACS) and a history of atrial fibrillation (AF) have indications for both dual antiplatelet therapy (DAPT) and oral anticoagulation (OAC). Triple therapy (TT), the combination of DAPT and OAC, is recommended in guidelines. This article provides a contemporary state-of-the-art review of the current evidence on DAPT for secondary prevention of patients with CAD and its future perspectives.

Verified
Journal Article
Open access
PDF file
BTBurak Toprak
Burak Toprak
ABAbdulkadir Bilgiç
Abdulkadir Bilgiç
RARahime Akın
Rahime Akın
MEMustafa Ekici
Mustafa Ekici
AKAHMET TURHAN KILIÇ
AHMET TURHAN KILIÇ
SKSerdar Keçeoğlu
Serdar Keçeoğlu
Background: Systemic inflammation plays a central role in determining postoperative outcomes in patients undergoing isolated coronary artery bypass grafting with cardiopulmonary bypass. Traditional inflammatory indices such as the neutrophil-to-lymphocyte ratio and the platelet-to-lymphocyte ratio have prognostic value; however, their dynamic behavior during cardiopulmonary bypass remains insufficiently characterized. More comprehensive indices, including the systemic immune-inflammation index and the systemic inflammatory response index, may help characterize early intraoperative inflammatory activity; however, their prognostic relevance should be regarded as exploratory and requires prospective validation. Methods: This retrospective nested case–control study included 245 patients who underwent isolated coronary artery bypass grafting, and intraoperative inflammatory indices during cardiopulmonary bypass were evaluated. Because of the nested case–control design, mortality cases were intentionally overrepresented to improve statistical power; therefore, the observed mortality rate does not reflect the true institutional mortality rate. Inflammatory indices (NLR, PLR, SII, and SIRI) were calculated at induction, at the 5th, 45th, and 90th minutes during cardiopulmonary bypass, and in the early postoperative period. Associations between these indices and in-hospital mortality were evaluated using univariate and multivariable logistic regression analyses. Predictive performance was assessed using receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC). Results: The final enriched analytical sample consisted of 51 mortality cases and 194 randomly sampled surviving controls. During cardiopulmonary bypass, inflammatory indices, particularly at the 5th minute, were significantly higher in patients who experienced mortality (p < 0.001 for all major indices). SII demonstrated the strongest predictive performance at the 5th minute (AUC = 0.790), followed by SIRI (AUC = 0.765), PLR (AUC = 0.687), and NLR (AUC = 0.681). In multivariable analysis, SII and SIRI measured at the 5th minute remained independent predictors of mortality. The addition of 5th-minute SII to the limited study-specific clinical model, which included age, ejection fraction, and preoperative creatinine, improved exploratory discrimination for in-hospital mortality (with AUC increasing from 0.698 to 0.797). Conclusions: Early intraoperative assessment of inflammatory indices during cardiopulmonary bypass may provide additional prognostic information in patients undergoing coronary artery bypass grafting. Composite indices, particularly SII and SIRI, showed stronger exploratory discrimination than traditional inflammatory markers in this enriched analytical sample. However, these findings should be considered hypothesis-generating and require prospective external validation before use in perioperative risk stratification or clinical decision-making can be recommended.