Impact of Preoperative Cardiac Evaluation and Recommendations on Morbidity and Mortality in Patients Undergoing Elective Non-Cardiac Interventions: A Retrospective Cohort Study

Abstract

Background

Preoperative cardiac evaluation aims to reduce cardiovascular risks in elective non-cardiac surgery, however its routine use is a subject of ongoing debate due to low event rates. This study examines patient characteristics, risk factors, diagnostic findings, recommendations, and outcomes to assess the value of these consultations and refine referral criteria.

Methods

This retrospective cohort study included 482 patients who underwent elective non-cardiac surgery with preoperative cardiology consultations at a tertiary hospital (March-September 2021). Data on demographics, cardiovascular risks, echocardiographic/electrocardiographic findings, recommendations, and outcomes (in-hospital complications, mortality, one-year survival, hospital stay) were analyzed.

Results

The median age of the patients was 69 years (interquartile range [IQR] 60-76), and 66.2% were male. Common surgeries included endoscopy/colonoscopy (31.7%) and genitourinary procedures (19.3%). Coronary artery disease (48.8%), hypertension (48.9%), and diabetes (37.8%) were prevalent. Most cases (96.5%) were asymptomatic, with ejection fractions > 50% (88.1%). Common recommendations included antiplatelet/anticoagulant modification (41.1%), although 54.8% of patients required no new recommendations. New diagnoses were rare (3.7%). In-hospital complications occurred in 2.9%, mortality in 0.6%, and one-year mortality in 1.7% of the patients, with a median hospital stay of 1 day (IQR 0-3).

Conclusions

Despite the high burden of comorbidities in the study cohort, low adverse event rates suggest many consultations may be unnecessary, particularly in asymptomatic patients with preserved function, supporting more selective referral criteria to enhance efficiency.

Abbreviations

ACC, American College of Cardiology

ADP, Adenosine diphosphate

AF, Atrial fibrillation

AHA, American Heart Association

CAD, Coronary artery disease

EF, Ejection fraction

ESC, European Society of Cardiology

IQR, Interquartile range

METs, Metabolic equivalents

NSQIP, National Surgical Quality Improvement Program

RCRI, Revised Cardiac Risk Index

INTRODUCTION

Elective non-cardiac surgery constitutes a substantial portion of procedural interventions worldwide, with millions of patients undergoing such operations annually, often in the context of an aging population increasingly afflicted by cardiovascular comorbidities.^1,2 The perioperative phase introduces unique stressors, including hemodynamic fluctuations, inflammatory responses, and prothrombotic state, which can precipitate adverse cardiac events such as myocardial injury, arrhythmias, or heart failure exacerbations, contributing significantly to postoperative morbidity and mortality.^3,4 To address these risks, international guidelines such as those from the American Heart Association/American College of Cardiology (AHA/ACC) and European Society of Cardiology (ESC) advocate for preoperative cardiac risk assessments using validated tools such as the Revised Cardiac Risk Index (RCRI) or the National Surgical Quality Improvement Program (NSQIP) calculator to stratify patients and inform management strategies ranging from medication adjustments to procedural deferrals.^5,6

Despite these structured approaches, the real world impact of preoperative cardiology consultations remains a subject of ongoing debate. While some studies have demonstrated reductions in perioperative complications through optimized therapies such as beta blockade or statins, others have highlighted inefficiencies including overtesting in low-risk individuals, unnecessary delays, and increased healthcare costs without proportional benefits.^7,8 In particular, routine referrals for asymptomatic patients with preserved functional capacity have been associated with low diagnostic yield, as evidenced by meta analyses showing minimal changes in management for most patients.^9,10 In Turkey, where the healthcare system often aligns with the ESC recommendations, local evidence on the efficacy of these consultations is limited, with few studies examining their association with outcomes in diverse surgical cohorts.¹¹ This gap is especially pertinent given regional variations in comorbidity profiles and resource availability, which may influence the generalizability of global guidelines.¹² In Turkey, evidence on preoperative cardiac risk factors remains limited, particularly for elective non-cardiac surgeries, where studies on specific cohorts such as older patients undergoing hip fracture surgery have identified factors including atrial fibrillation (AF), pulmonary artery systolic pressure, and insulin dependency as predictors of in-hospital and long-term mortality.^13,14 Recent advances in risk prediction models for myocardial injury in non-elective surgery and artificial intelligence-based systems for short-term mortality in patients with acute conditions such as pulmonary embolism highlight the need for refined, context-specific tools.^15,16 The present retrospective cohort study was designed to investigate the characteristics of patients referred for preoperative cardiology consultations prior to elective non-cardiac surgery at a tertiary center in İstanbul, Türkiye, with the aim of providing evidence from a diverse cohort with low adverse event rates to inform more selective referral criteria. By evaluating demographic features, cardiovascular risk factors, diagnostic findings, issued recommendations, and their association with in-hospital morbidity, mortality, and one year survival, this analysis aimed to evaluate the practical value of these evaluations. Furthermore, it sought to contribute to the discourse on optimizing referral criteria, potentially advocating for more targeted approaches to enhance efficiency and patient outcomes while minimizing unnecessary interventions.^17,18

METHODS

Study design and setting

This single-center retrospective cohort study was conducted at the Health Sciences University Sultan 2. Abdülhamid Han Training and Research Hospital from March 1, 2021 to September 30, 2021. The hospital serves a diverse urban demographic with a high volume of cardiology referrals. The study complied with the STROBE guidelines for observational research. Ethics approval was granted by the Hamidiye Non-interventional Research Ethics Board on May 15, 2024 (protocol 25631, decision 118), in accordance with the Declaration of Helsinki.

Participants

Adults aged 18 years or older referred for a preoperative cardiology consultation prior to elective non-cardiac surgery were included. The exclusion criteria were emergency cases, cardiac surgeries, incomplete documentation, or a lack of outcome data. The final cohort of 482 patients consisted of consecutive referrals, without sampling bias.

Variables

Collected variables included demographics (age, sex), surgery types, cardiovascular risks (e.g., coronary disease, hypertension), therapies (e.g., beta-blockers, anticoagulants), symptoms (e.g., dyspnea), functional capacity (metabolic equivalents [METs]), electrocardiography (e.g., AF), echocardiography (ejection fraction [EF], valvular issues), recommendations (e.g., drug discontinuation), new diagnoses, and outcomes (in-hospital cardiac complications needing reconsultation, mortality, one-year mortality, hospital stay). Cardiac complications were defined as events prompting reintervention; mortality was verified through records and national registries.

Data source and measurements

Electronic health records provided all data, including lab results and imaging. EFs were categorized (< 40%, 40-50%, > 50%). METs were patient-reported.

Bias

Selection bias was mitigated by including all eligible patients. Information bias was reduced via standardized abstraction. Confounders were noted descriptively.

Study size

The study size was determined by the number of eligible patients referred for preoperative cardiology consultation at the study center during the defined data collection period (March 1, 2021 to September 30, 2021). All consecutive patients meeting the inclusion criteria were included in the analysis to minimize selection bias, resulting in a final cohort of 482 participants.

Quantitative variables

Continuous variables were assessed for normal distribution using the Kolmogorov-Smirnov test and Shapiro-Wilk test to determine appropriate summary measures. Due to non-normal distribution observed in most continuous variables (e.g., age, hospital stay duration), these were summarized using medians with interquartile range (IQR). For the few normally distributed variables, means with standard deviation would have been used, but none met this criterion in the final dataset. Categorical variables were summarized as frequencies (n) and percentages (%). Missing data were minimal (< 1% across variables) following exclusion for incomplete records, and no imputation was required; cases with missing data on primary outcomes were excluded as per the participant criteria.

Statistical methods

All statistical analyses were conducted using Statistical Package for the Social Sciences version 27.0 (IBM Corp., Armonk, NY, USA). The study was descriptive in intent, focusing on the comprehensive characterization of patient profiles, risk factors, consultation recommendations, and perioperative outcomes. Continuous variables were summarized as medians with IQR due to non-normal distribution, while categorical variables were summarized as frequencies and percentages. Given the descriptive nature of the study design and low incidence of adverse events (e.g., in-hospital mortality at 0.6%), formal inferential statistics and hypothesis testing were not performed.

RESULTS

Participant characteristics and surgical distribution

The study cohort comprised 482 patients who underwent elective non-cardiac surgery following a preoperative cardiology consultation. The median age of the patients was 69 years (IQR 60-76 years), reflecting an older population typical for such procedures, 319 (66.2%) were male, and 163 (33.8%) were female. The surgical procedures varied widely, with gastrointestinal endoscopy or colonoscopy being the most common (153 patients, 31.7%), followed by genitourinary surgeries (93 patients, 19.3%), cholecystectomy or other gastrointestinal operations (78 patients, 16.2%), cataract or ocular procedures (42 patients, 8.7%), bronchoscopy or endobronchial ultrasound (30 patients, 6.2%), neurosurgical interventions (27 patients, 5.6%), orthopedic surgeries primarily for hip fractures (23 patients, 4.8%), oral or nasal cavity procedures (20 patients, 4.1%), and thoracic surgeries (16 patients, 3.3%). This distribution underscores the diversity of elective non-cardiac surgeries encountered in a tertiary care setting (Table 1). Coronary artery disease (CAD) was documented in 235 patients (48.8%), and the subtypes are detailed in Supplementary Table 1.

Table 1. Baseline characteristics, surgical procedures, cardiovascular risk factors, and ongoing medical therapies. (Additional CAD subtypes are demonstrated in Supplementary Table 1).

Category	Value
Patient demographics
Age (years), median (IQR)	69 (60-76)
Gender
Female	163 (33.8%)
Male	319 (66.2%)
Surgery type
Bronchoscopy/EBUS	30 (6.2%)
Endoscopy/colonoscopy	153 (31.7%)
Genitourinary surgery	93 (19.3%)
Cholecystectomy/gastrointestinal surgery	78 (16.2%)
Orthopedic surgery (hip fracture)	23 (4.8%)
Neurosurgery	27 (5.6%)
Thoracic surgery	16 (3.3%)
Cataract eye operations	42 (8.7%)
Oral and nasal cavity procedures	20 (4.1%)
Risk factors
Coronary artery disease	235 (48.8%)
DM	182 (37.8%)
Insulin (among DM patients)	25 (13.7%)
Hypertension	236 (48.9%)
Cerebrovascular disease	18 (3.7%)
Chronic kidney disease	10 (2.1%)
Hyperlipidemia	23 (4.8%)
Smoking	43 (8.9%)
Cancer	4 (0.8%)
Family history	1 (0.2%)
History of MI	15 (3.1%)
ASA	222 (46%)
ADP receptor inhibitors	91 (18.9%)
Warfarin	24 (5%)
NOAC	42 (8.7%)
Medical treatment
Beta blockers	190 (39.4%)
Calcium channel blockers	51 (10.6%)
ACE inhibitors/ARB	144 (29.9%)
Mineralocorticoid receptor antagonists	15 (3.1%)
Diuretics	12 (2.5%)
SGLT-2 inhibitors	7 (1.5%)
Statins	132 (27.4%)
Ranolazine	9 (1.9%)
Trimetazidine	5 (1%)
Nitrates	10 (2.1%)

Data are presented as median (IQR) for non-normally distributed continuous variables and as number (percentage) for categorical variables. Percentages are calculated relative to the total sample size (n = 482) unless otherwise specified (e.g., insulin use is relative to patients with diabetes mellitus).

ACE, angiotensin-converting enzyme; ADP, adenosine diphosphate; ARB, angiotensin receptor blocker; ASA, acetylsalicylic acid (aspirin); DM, diabetes mellitus; EBUS, endobronchial ultrasound; IQR, interquartile range; MI, myocardial infarction; NOAC, non-vitamin K antagonist oral anticoagulant; SGLT-2, sodium-glucose cotransporter-2.

Cardiovascular risk factors and medical therapies

Cardiovascular comorbidities were highly prevalent in the cohort. CAD was documented in 235 patients (48.8%), with subtypes including non-obstructive disease in 71 patients (14.8%), prior percutaneous coronary intervention in 94 patients (19.5%), coronary artery bypass grafting in 60 patients (12.4%), and combined interventions in 10 patients (2.1%). In addition, 236 (48.9%) patients had hypertension, 182 (37.8%) had diabetes mellitus (of whom 25 [13.7%] were insulin dependent), 18 (3.7%) had cerebrovascular disease, 10 (2.1%) had chronic kidney disease, 23 (4.8%) had hyperlipidemia, 4 (0.8%) had malignancy, 1 (0.2%) had a positive family history of cardiovascular events, 15 (3.1%) had prior myocardial infarction, and 43 (8.9%) were active smokers.

Ongoing medical therapies reflected the risk profile of the cohort (Table 1). Antiplatelet agents were common, with aspirin used in 222 patients (46.0%) and adenosine diphosphate (ADP) receptor inhibitors in 91 patients (18.9%). Anticoagulation included warfarin in 24 patients (5.0%) and non-vitamin K oral anticoagulants in 42 patients (8.7%). Beta-blockers were prescribed to 190 patients (39.4%), calcium channel blockers to 51 patients (10.6%), angiotensin-converting enzyme inhibitors or angiotensin receptor blockers to 144 patients (29.9%), mineralocorticoid receptor antagonists to 15 patients (3.1%), diuretics to 12 patients (2.5%), sodium-glucose cotransporter-2 inhibitors to 7 patients (1.5%), statins to 132 patients (27.4%), ranolazine to 9 patients (1.9%), trimetazidine to 5 patients (1.0%), and nitrates to 10 patients (2.1%) (Table 1).

Cardiac symptoms, functional capacity, and diagnostic findings

Active cardiac symptoms were notably infrequent, with 465 patients (96.5%) reporting none. Minor symptoms included dyspnea in 11 patients (2.3%), chest pain in 3 patients (0.6%), fatigue in 1 patient (0.2%), and peripheral edema in 2 patients (0.4%). Functional capacity, assessed via METs, was generally preserved; 385 patients (79.9%) achieved 4-10 METs, 58 patients (12.0%) exceeded 10 METs, and only 39 patients (8.1%) fell below 4 METs.

Electrocardiographic evaluations showed sinus rhythm in 428 patients (88.8%) and AF or flutter in 54 patients (11.2%). Echocardiographic assessments (Table 2) revealed preserved left ventricular EF in most of the patients, with values greater than 50% in 425 patients (88.1%), 40-50% in 36 patients (7.5%), and less than 40% in 21 patients (4.4%). Valvular pathologies were uncommon, with aortic valve replacement in 5 patients (1.0%), mitral valve replacement in 1 patient (0.2%), bioprosthetic valves in 4 patients (0.8%), moderate or severe mitral stenosis in 3 patients (0.6%), moderate or severe aortic stenosis in 13 patients (2.7%), moderate or severe mitral regurgitation in 3 patients (0.6%), and moderate or severe aortic regurgitation in 5 patients (1.0%) (details of valve pathology subtypes are shown in Supplementary Table 2).

Table 2. Cardiac symptoms, functional capacity, diagnostic findings, preoperative recommendations, new diagnoses, and postoperative outcomes (Detailed valve pathology subtypes are listed in the Supplementary Table 2).

Category	Value
Cardiac symptoms present
Dyspnea	11 (2.3%)
Chest pain	3 (0.6%)
Fatigue	1 (0.2%)
Leg swelling	2 (0.4%)
No active symptoms	465 (96.5%)
Exercise capacity
< 4 METs	39 (8.1%)
4-10 METs	385 (79.9%)
> 10 METs	58 (12%)
Electrocardiography	428 (88.8%)
Sinus rhythm
Atrial fibrillation/flutter	54 (11.2%)
Echocardiography ejection fraction classification	21 (4.4%)
EF < 40%
EF 40-50%	36 (7.5%)
EF > 50%	425 (88.1%)
Echocardiography valve pathology present	34 (7%)
Preoperative recommendations
Discontinuation of warfarin or NOAC	48 (10%)
Discontinuation of ASA or ADP receptor inhibitors	150 (31.1%)
Blood pressure regulation	2 (0.4%)
Heart failure medication adjustment	3 (0.6%)
Initiation of statins	4 (0.8%)
Lifestyle changes	0 (0%)
Deferral of surgery	15 (3.1%)
No additional recommendation	264 (54.8%)
New cardiac diagnosis made
Coronary artery disease	7 (1.4%)
Heart failure	4 (0.8%)
Moderate or severe valve disease	1 (0.2%)
Hypertension	3 (0.6%)
Atrial fibrillation/flutter	3 (0.6%)
Other arrhythmias	2 (0.4%)
No new diagnosis	464 (96.3%)
Postoperative outcomes
Did postoperative cardiac complication develop, reconsultation occur? (Yes)	14 (2.9%)
Hospital stay duration (days), median (IQR)	1 (0-3)
Did in-hospital death occur? (Yes)	3 (0.6%)
Did death occur within the last 1 year? (Yes)	8 (1.7%)

Data are presented as median (IQR) for non-normally distributed continuous variables and as number (percentage) for categorical variables. Percentages are calculated relative to the total sample size (n = 482).

AVR, aortic valve replacement; EF, ejection fraction; IQR, interquartile range; METs, metabolic equivalents; MVR, mitral valve replacement; NOAC, non-vitamin K antagonist oral anticoagulant.

Preoperative recommendations and new diagnoses

Preoperative recommendations focused on perioperative management adjustments. Discontinuation of warfarin or non-vitamin K oral anticoagulants was advised in 48 patients (10.0%), cessation of aspirin or ADP receptor inhibitors in 150 patients (31.1%), blood pressure optimization in 2 patients (0.4%), heart failure medication adjustments in 3 patients (0.6%), initiation of statins in 4 patients (0.8%), and postponement of surgery in 15 patients (3.1%). Notably, no additional recommendations were deemed necessary in 264 patients (54.8%), and lifestyle modifications were not suggested in any case (0.0%).

New cardiac diagnoses during consultation were rare, occurring in only 18 patients overall (3.7%). These included CAD in 7 patients (1.4%), heart failure in 4 patients (0.8%), moderate or severe valvular disease in 1 patient (0.2%), hypertension in 3 patients (0.6%), AF or flutter in 3 patients (0.6%), and other arrhythmias in 2 patients (0.4%). The vast majority of the patients (n = 464, 96.3%) did not receive a new diagnosis (Table 2).

Outcome measures

Postoperative cardiac complications requiring reconsultation developed in 14 patients (2.9%). Two of these patients were diagnosed with type II myocardial infarction, and 3 were diagnosed with decompensated heart failure. One of the two patients diagnosed with myocardial infarction was treated with percutaneous coronary intervention, and the other was treated with a coronary artery bypass grafting procedure. The median duration of hospital stay was 1 day (IQR 0-3 days) (Table 2). In-hospital mortality occurred in 3 patients (0.6%), and mortality within one year after the procedure was recorded in 8 patients (1.7%). The cause of death was non-cardiac in all of these patients.

DISCUSSION

Summary of key results

The study cohort was characterized by advanced age and substantial cardiovascular comorbidities. They all underwent preoperative cardiac evaluations that predominantly resulted in minor medication adjustments or no interventions, correlating with minimal in-hospital complications (2.9%) and mortality (0.6%), as well as low one year mortality (1.7%). Despite the high-risk profile, these outcomes suggest effective risk management but also raise questions about the necessity of routine consultations, given the rarity of new diagnoses (3.7%) and active symptoms (3.5%)^9,10 (Central Illustration).

Central Illustration.

Preoperative cardiac evaluation and the relation to postoperative outcomes. CAD, coronary artery disease; EF, ejection fraction; IQR, interquartile range.

Interpretation in the context of existing evidence

The observed prevalence of CAD and hypertension aligns with large-scale registries, in which these factors were associated with higher perioperative risk, often warranting optimizations such as beta-blocker continuation in a significant portion of cases, which has been linked to reduced nonfatal infarctions in vulnerable populations.^11,12 Although the low complication rate echoes meta analyses showing that guideline-based assessments can lower events through targeted therapies, over half of the consultations in the present study yielded no recommendations, implying potential overreferral.^17,18 This is particularly evident in the asymptomatic patients with preserved EF (96.5%, including 88.1% with EF ≥ 50%), where functional capacity (4 METs in 91.9%) predicted favorable outcomes, consistent with studies emphasizing METs as a robust indicator over extensive testing.^20,21

Valvular pathologies were infrequent, leading to deferrals in only 3.1% of cases, supporting guidelines that reserve interventions for severe cases due to elevated mortality risks.^22,23 The brief hospital stay (median 1 day) indicates streamlined care, comparable to cohorts where optimization shortens admissions, however the minimal new diagnosis rate suggests that the consultations often confirmed rather than revealed issues, raising questions over their routine utility.^24,25 In addition, the one-year mortality (1.7%) was lower than rates reported in older frail groups, possibly due to the functional preservation in our cohort (majority > 4 METs), reinforcing that consultations may be superfluous in such stable patients.^26,27

Expanding on this, contemporary guidelines such as the 2022 ESC and 2024 AHA/ACC updates advocate selective testing, noting that routine evaluations in low-risk scenarios inflate costs without improving outcomes, with evidence from randomized trials showing no benefit in mortality from broad preoperative stress testing.^2,3 In fact, recent studies have highlighted that up to 70% of consultations in asymptomatic patients lead to no actionable changes, contributing to healthcare inefficiencies and patient anxiety without reducing events.^28,29 Our findings corroborate this, as most of the cases did not have recommendations, implying a substantial proportion of unnecessary referrals, potentially driven by defensive medicine or outdated protocols rather than evidence-based need.^30,31

Furthermore, the low yield of electrocardiography and echocardiography aligns with previous findings that these tests add little prognostic value beyond clinical indices in intermediate-risk groups, as per systematic reviews demonstrating high negative predictive values but poor positive predictive values, leading to overtesting.^32,33 This overutilization is particularly problematic in resource-limited settings such as Türkiye, where selective criteria focusing on poor METs or unstable conditions could reallocate efforts to high-risk groups, reducing delays and costs.^6,34 Recent analysis including population-based estimates from 2022 reported a 13.4% one-year mortality rate after major surgery in older adults, far exceeding our 1.7%, suggesting our low rate may stem from a case mix heavily weighted toward lower-risk procedures (e.g., endoscopy) and an overcautious referral threshold that captured many low-risk patients unnecessarily.⁹

Critically, while our study did not demonstrate any safety concerns regarding the patients who received consultations, it underscores a broader issue that most preoperative cardiology consultations appeared to be unnecessary, especially for elective procedures in asymptomatic individuals with good functional status. This is supported by recent evidence indicating that risk calculators such as the NSQIP and RCRI are sufficient for stratification without the need for specialist input in 80% of cases, and that consultations should be reserved for those with scores indicating elevated risk.^4,5 Overconsultation not only strains systems but may inadvertently increase interventions such as medication holds that carry bleeding risks, as seen in the 31.1% antiplatelet discontinuation rate in the present study, which may have been unnecessary according to updated aspirin guidelines.^28,29 Thus, shifting to algorithm-driven primary care screening could enhance efficiency, aligning with calls for deimplementation in perioperative care to focus on value-based practices.^30,31

Generalizability

The results from this urban tertiary center may be generalizable to similar comorbid populations, however they should be applied with caution to rural or lower resource areas with differing referral patterns.²²

Limitations

The retrospective nature of the study precludes causality; the single-center design risks bias. Unassessed confounders such as frailty may underestimate risks. Reliance on records could miss mortality data. The absence of a nonconsulted control group limits direct comparisons of consultation necessity. A significant proportion of the cohort (31.7%) underwent endoscopic procedures. While these procedures carry cardiovascular risks, they are generally lower than for major open surgeries, which limits the extrapolation of our low adverse event rates to high-risk surgical populations. In addition, due to the retrospective nature of the study, we were not able to acquire the American Society of Anesthesiologists risk classification of the patients from the electronic medical records, since these were hand recorded on printed forms. To alleviate this to an extent, we reported the symptomatic status and METs of the patients. In addition, while individual risk factors were recorded, composite risk scores such as the RCRI or NSQIP were not routinely calculated in the preoperative notes, precluding a retrospective stratification based on these specific indices.

New knowledge gained

The results of this study revealed that preoperative cardiology consultations in patients undergoing elective non-cardiac surgery primarily confirmed existing risks rather than uncover new ones, with over 50% yielding no actionable changes. These findings highlight the potential for selective referral criteria, focusing on symptomatic or low functional capacity patients, to reduce unnecessary evaluations while maintaining low adverse event rates. These insights support the deimplementation of routine consultations in stable cohorts, optimizing resource allocation in high-comorbidity settings.

CONCLUSIONS

Preoperative cardiac consultations were associated with low adverse events, although the absence of a control group precludes direct causal attribution. In a high-comorbidity cohort with low adverse events, the predominance of no interventions highlights that routine testing often has low diagnostic yield, particularly in asymptomatic patients with preserved functional capacity (> 4 METs). Future protocols should emphasize selective referrals to improve efficiency and patient-centered care.^32-34

DECLARATION OF CONFLICT OF INTEREST

All the authors declare no conflicts of interest.

SUPPLEMENTARY MATERIALS

Supplementary Table 1. Subtypes of patients with coronary artery disease.

Coronary artery disease subtype	Value
Non-obstructive coronary artery disease	71 (14.8%)
Percutaneous coronary intervention	94 (19.5%)
CABG	60 (12.4%)
CABG + percutaneous coronary intervention	10 (2.1%)

CABG, coronary artery bypass grafting.

Supplementary Table 2. Subtypes of valve pathologies.

Valve pathology subtype	Value
AVR	5 (1%)
MVR	1 (0.2%)
Bioprosthetic valve	4 (0.8%)
Moderate or severe mitral stenosis	3 (0.6%)
Moderate or severe aortic stenosis	13 (2.7%)
Moderate or severe mitral regurgitation	3 (0.6%)
Moderate or severe aortic regurgitation	5 (1%)

AVR, aortic valve replacement; MVR, mitral valve replacement.

FUNDING

None.

DATA AVAILABILITY

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

AUTHOR CONTRIBUTIONS

Süha Asal: Conceptualization, Methodology, Investigation, Data curation, Writing – original draft, Writing – review & editing, Supervision. Şahhan Kiliç: Investigation, Data curation, Writing – review & editing. Emrecan Uygun: Investigation, Data curation, Writing – review & editing. Mert Babaoğlu: Investigation, Data curation, Writing – review & editing. Mustafa İnceoğlu: Investigation, Data curation, Writing – review & editing. Samet Yavuz: Investigation, Data curation, Writing – review & editing. Yetkin Korkmaz: Investigation, Data curation, Writing – review & editing. Tufan Çinar: Methodology, Writing – review & editing. Ahmet Lütfullah Orhan: Methodology, Supervision, Writing – review & editing. All authors read and approved the final manuscript.