Obstructive Sleep Apnea and Cardiovascular Disease: Where Do We Stand?

Obstructive sleep apnea is common in adults with cardiovascular disease. Accumulating evidence suggests an association between obstructive sleep apnea and cardiovascular disease independent of the traditionally recognized cardiovascular disease risk factors. Observational studies indicate that obstructive sleep apnea is a risk factor for development of cardiovascular disease and that alleviation of obstructive events with positive airway pressure may improve cardiovascular disease outcomes. However, recent randomized controlled trials have not supported the beneficial effect of positive airway pressure in cardiac populations with concomitant obstructive sleep apnea. Some evidence suggests that the relationship between obstructive sleep apnea and traditionally recognized cardiovascular disease risk factors is bidirectional, suggesting that patients with cardiovascular disease may also develop obstructive sleep apnea and that efficient treatment of cardiovascular disease may improve obstructive sleep apnea. Recent data also indicate that the apnea-hypopnea index, which is commonly used as a diagnostic measure of obstructive sleep apnea severity, has limited value as a prognostic measure for cardiovascular disease outcomes. Novel markers of obstructive sleep apnea-associated hypoxic burden and cardiac autonomic response seem to be strong predictors of adverse cardiovascular disease outcomes and response to treatment of obstructive sleep apnea. This narrative review and position paper from the Turkish Collaboration of Sleep Apnea Cardiovascular Trialists aims to update the current evidence about the relationship between obstructive sleep apnea and cardiovascular disease and, consequently, raise awareness for health professionals who deal with cardiovascular and respiratory diseases to improve the ability to direct resources at patients most likely to benefit from treatment of obstructive sleep apnea and optimize treatment of the coexisting cardiovascular diseases. Moreover, the Turkish Collaboration of Sleep Apnea Cardiovascular Trialists aims to contribute to strengthening the efforts of the International Collaboration of Sleep Apnea Cardiovascular Trialists in this context.

The Relationship Between Mitral Annular Calcification and Controlling Nutritional Status Score.

INTRODUCTION: The relationship between mitral annular calcification (MAC) and the controlling nutritional status (CONUT) score has not been previously studied. In this study, we investigated the relationship between MAC and CONUT score to evaluate the nutritional status of patients with MAC. METHODS: A total of 275 patients, including 150 patients with MAC and 125 patients without MAC, who presented to a cardiology outpatient clinic were enrolled in the study. RESULTS: There was no difference in the CONUT score between the two groups. Correlation analysis indicated that CONUT score was positively correlated with left atrial (LA) diameter (r=0.190, P=0.020) and interventricular septum thickness (r=0.179, P=0.028) in the MAC+ group. In multivariate regression analysis, only LA diameter (odds ratio 95% confidence interval = 1,054-1,189, P=0.0001) was independently associated with MAC. CONCLUSION: The present study investigated the relationship between CONUT score and MAC for the first time in the literature. We demonstrated that CONUT score was not significantly higher in patients with MAC without chronic diseases. However, CONUT score was correlated with LA diameter in patients with MAC. We therefore conclude that, for patients admitted with MAC and high LA diameter, CONUT is a valuable nutritional and inflammatory status index.

Incidence and predictors of complete atrioventricular conduction recovery among patients with heart block.

Aim: In this study, our aim was to determine clinical factors related to the recovery of the conduction system in patients presenting with atrioventricular (AV) block. Materials & methods: A total of 178 patients who were hospitalized at a tertiary center due to second- or third-degree AV block were retrospectively analyzed. Results: During hospital follow-up, 19.1% of patients had fully recovered from AV block. According to a logistic regression analysis; younger age (odds ratio [OR]: 0.950; 95% CI: 0.932-0.967; p < 0.001), presenting with acute coronary syndrome (OR: 18.863; 95% CI: 3.776-94.222; p < 0.001), ß-blocker usage (OR: 12.081; 95% CI: 3.498-41.726; p < 0.001), high serum creatinine levels (OR: 4.338; 95% CI: 2.110-8.918; p < 0.001) and no calcification at the aortic valve (OR: 0.189; 95% CI: 0.050-0.679; p = 0.011) were found to be related to resolution of AV block. Conclusion: It is crucial to know the reversible causes of AV block to prevent unnecessary permanent pacemaker implantation.

Predictors of in-hospital mortality in very eldery patients presenting with acute coronary syndrome: A single-center study.

OBJECTIVE: Acute coronary syndrome (ACS) has become more frequent in the elderly population due to increased life expectancy. The aim of this trial was to determine clinical and laboratory factors related to in-hospital mortality in patients over 80 years of age who presented with ACS. METHODS: A total 171 patients (86 men, median age 83 years) who were over 80 years of age and were hospitalized due to a diagnosis of ACS were enrolled in this study. The patients' demographic data, clinical features, and laboratory values were screened retrospectively from hospital records. RESULTS: During the follow-up period, 19 of 171 patients (11.1%) died. The causes of death were cardiogenic shock (n=6, 31.5%), acute renal failure (n=6, 31.5%), arrhythmia (n=4, 21%), and septic shock (n=3, 15.7%). ST-segment elevation myocardial infarction presentation was more common among those who died [14 (73.7%) vs. 31 (20.5%); p<0.001]. Patients who died during in-hospital follow-up also had higher peak troponin [3.1 ng/mL (7.2) vs. 0.3 ng/mL (1.6); p<0.001] and creatine kinase-MB levels [96.7 ng/mL (194) vs. 10.9 ng/mL (36.2); p<0.001]. The results indicated that a high Global Registry of Acute Coronary Events (GRACE) risk score [odds risk (OR): 1.074, 95% confidence interval (CI): 1.039-1.110; p<0.001], ejection fraction (EF) ≤40% (OR: 8.113, 95% CI: 1.101-59.773; p=0.040), or no use of an angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) (OR: 0.075, 95% CI: 0.006-0.995; p=0.049) was significantly associated with in-hospital mortality. CONCLUSION: Presentation with a high GRACE risk score, no use of an ACEI/ARB, and a low EF at admission were associated with in-hospital mortality in ACS patients more than 80 years old.

Severity of coronary atherosclerosis in patients with COPD.

BACKGROUND AND AIMS: Chronic obstructive pulmonary disease (COPD) has many comorbidities such as coronary artery disease (CAD) and stroke. Chronic low-grade systemic inflammation and oxidative stress play a significant role in CAD and COPD. We analysed that impact of COPD on intensity and severity of coronary artery lesions on the angiogram in the groups of patients with COPD according to the Global Initiative for Obstructive Lung Disease (GOLD) grades updated in 2015. METHODS: The study included 102 COPD patients and 80 randomly selected subjects without any pulmonary disease who underwent coronary angiography. According to the GOLD grade for COPD, patients were divided into four groups: A, B, C and D. The severity and extent of CAD were determined using the Gensini score. RESULTS: There were no significant between-group differences in age, body mass index, smoking history, plasma lipids levels, frequency of hypertension, diabetes and CAD. The mean Gensini score in patients with COPD was significantly higher than those without (respectively, 25.7 ± 32.9 vs 17.5 ± 24.8, P = 0.01). While Gensini score was the highest level in the patient group D (64.9 ± 34.9), it was the lowest level in the patient group A (10.2 ± 19.4, P = 0.0001). The Gensini scores increased in accordance with increases in the GOLD grades. We observed that COPD was independently predictive for Gensini score after a multi-variate logistic regression analysis (odds ratio 1.374; 95% confidence interval 1.672-9.232; P = 0.001). CONCLUSION: Severity and intensity of coronary atherosclerosis increases in accordance with increases in the GOLD grades for COPD.

Turkish registry for diagnosis and treatment of acute heart failure: TAKTIK study.

OBJECTIVE: The goal of this study was to develop a national database of patients hospitalized in Turkey with acute heart failure (AHF) using evaluations of diagnostic and therapeutic approaches. METHODS: Patient data were collected using an Internet-based survey. A total of 588 patients were enrolled from 36 participating medical centers across the country. RESULTS: Mean age was 62±13 years and 38% of the patients were female. Ratio of de novo AHF to study cohort was 24%. Coronary heart disease and hypertension were found in 61% and 53% of the patients, respectively. Valvular heart disease was the underlying cause in 46% of heart failure patients. The most frequent factor associated with decompensation was noncompliance with treatment, observed in 34% of patients. Systolic blood pressure was 125±28 mmHg and heart rate was 93±22 beats/minute in the cohort. The most common findings on physical examination were inspiratory fine crackles (84%), peripheral edema (64%), and cold extremities in 34%. Mean ejection fraction (EF) measured at admission was 33±13%. Preserved EF (?%40) was present in 20% of patients. On admission, 60%, 46%, and 40% of patients were using angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, or aldosterone antagonist, respectively. In-hospital events were reported as 3.4% death, 1.6% stroke and 2% myocardial infarction. CONCLUSION: Compared to previous data collected around the world, AHF patients in Turkey were younger, had more frequently valvular heart disease as the underlying cause, and were more noncompliant with medical treatment, but overall mortality was lower. Drugs shown to reduce mortality, and which also form the basis of guideline-directed medical therapy, are still used inadequately.

Evaluation of cardiac biomarkers and right ventricular dysfunction in patients with acute pulmonary embolism.

OBJECTIVE: Right ventricular dysfunction (RVD) with myocardial damage may lead to fatal complications in patients with acute pulmonary embolism (PE). Cytoplasmic heart-type fatty acid-binding protein (HFABP) and the N-terminal fragment of its prohormone (NT-proBNP) are sensitive and specific biomarkers of myocardial damage. We evaluated RVD and cardiac biomarkers for myocardial damage and short-term mortality in patients with acute PE. METHODS: We analyzed 41 patients (24 females, 17 males) with confirmed acute PE prospective. Three groups (massive, submassive, and non-massive) of patients were defined, based on systemic systolic blood pressure measured on admission and RVD by transthoracic echocardiography (TTE). Also, systolic (s) and mean (m) pulmonary artery pressures (PAPs) were recorded by TTE, and plasma concentrations of cardiac troponin T (cTn-T), NT-proBNP, and HFABP were evaluated 6 month follow-up. RESULTS: Seventeen (41.5%) patients experienced a complicated clinical course in the 6-month follow-up for the combined end-point, including at least one of the following: death (n=12, 29.3%; 3 PE-related), chronic PE (n=4, 9.8%), pulmonary hypertension (n=2, 4.9%), and recurrent PE (n=1, 2.4%). Multivariate hazard ratio analysis revealed HFABP, NT-proBNP, and PAPs as the 6-month mortality predictors (HR 1.02, 95% CI 1.01-1.05; HR 1.01, 95% CI 1.01-1.04; and HR 1.02, 95% CI 1.02-1.05, respectively). CONCLUSION: HFABP, NT-proBNP, and PAPs measured on admission may be useful for short-term risk stratification and in the prediction of 6-month PE-related mortality in patients with acute PE.

Effect of 10-Week Supervised Moderate-Intensity Intermittent vs. Continuous Aerobic Exercise Programs on Vascular Adhesion Molecules in Patients with Heart Failure.

OBJECTIVE: Abnormal expression of cellular adhesion molecules may be related to endothelial dysfunction, a key feature in chronic heart failure. This study compares the effects of 10-wk supervised moderate-intensity continuous aerobic exercise (CAE) and intermittent aerobic exercise (IAE) programs on markers of endothelial damage, disease severity, functional and metabolic status, and quality-of-life in chronic heart failure patients. DESIGN: Fifty-seven patients between 41 and 81 yrs with New York Heart Association class II-III chronic heart failure and with a left ventricular ejection fraction of 35%-55% were randomized into three groups: nonexercising control, CAE, and IAE, which exercised three times a week for 10 wks. Endothelial damage was assessed by serum markers of vascular cell adhesion molecule-1, serum intercellular adhesion molecule-1, and nitric oxide; disease severity was measured by left ventricular ejection fraction and N-terminal probrain natriuretic peptide; metabolic status was evaluated by body composition analysis and lipid profile levels; functional status was evaluated by cardiorespiratory exercise stress test and 6-min walking distance; quality-of-life was assessed with Left Ventricular Dysfunction-36 and Short-Form 36 questionnaires at the baseline and at the end of the 10th week. RESULTS: Significant decreases in serum vascular cell adhesion molecule-1 or serum intercellular adhesion molecule-1 in IAE and CAE groups after training were found, respectively. Resting systolic and diastolic blood pressure, peak systolic and diastolic blood pressure, 6-min walking distance, and the mental health and vitality components of Short-Form 36 improved in the CAE group, whereas left ventricular ejection fraction and 6-min walking distance improved in the IAE group compared with the control group. CONCLUSIONS: Both moderate-intensity CAE and IAE programs significantly reduced serum markers of adhesion molecules and prevented the change in VO2 in patients with chronic heart failure.

Tirofiban-induced acute profound thrombocytopenia after primary angioplasty.

Glycoprotein IIb/IIIa inhibitors are used in the acute coronary syndromes and percutaneous coronary intervention as antiplatelet agents. However, these agents induce thrombocytopenia in approximately 1% to 5% of patients, and may lead to bleeding complications. Abciximab is associated with higher incidence of thrombocytopenia than eptifibatide and tirofiban. We describe a case of acute profound thrombocytopenia due to on tirofiban treatment in a patient who underwent primary angioplasty.

Increased red blood cell deformability and decreased aggregation as potential adaptive mechanisms in the slow coronary flow phenomenon.

OBJECTIVE: At present, the precise pathophysiology of the slow coronary flow phenomenon (SCFP) is still unknown and there is no consensus as to how it should be treated. The rheological factors affect the clinical course of various cardiovascular diseases. We studied the intrinsic properties of blood in the SCFP. MATERIALS AND METHODS: Twenty-six SCFP patients who had angiographically confirmed SCFP, and had otherwise normal epicardial coronary arteries, were included in our study, as were 30 healthy individuals with normal results from arteriography. Red blood cell (RBC) deformability, aggregation, whole-blood viscosity at both native and standard (40%) hematocrit, and plasma viscosity were determined in each individual. The results were analyzed using a Mann-Whitney U-test, an unpaired t-test, and a χ-test, where appropriate. RESULTS: The mean thrombolysis in myocardial infarction frame count was significantly higher in SCFP patients than in the controls. RBC deformability measured at five different shear rates was significantly higher in SCFP patients than in the controls. The RBC aggregation index was lower in SCFP patients. There were no statistically significant differences in RBC aggregation half-time (t1/2) and aggregation amplitude, whole-blood viscosity, and plasma viscosity between the two groups. CONCLUSION: The SCFP is associated with increased RBC deformability and decreased RBC aggregation. These hemorheological alterations, possibly also contributing factors in limiting the pathogenesis, can especially serve as beneficial adaptive mechanisms in the SCFP.

[Non-invasive mechanical ventilation therapy in patients with heart failure]. / Kalp yetersizligi hastalarinda noninvaziv mekanik ventilasyon tedavisi.

Non-invasive mechanical ventilation (NIMV) therapy in patients with acute heart failure (HF) improves left ventricular functions via decreasing left ventricular afterload and reduces intubation rate and short-term mortality. In patients with chronic HF, NIMV therapy eliminates central and obstructive apneas and Cheyne-Stokes respiration, and improves morbidity. There are essentially three modes of NIMV that are used in the treatment of HF: Continuous positive airway pressure (CPAP), bilevel positive airway pressure (BIPAP) and adaptive servo-ventilation (ASV). Hereby, NIMV therapy in patients with acute and chronic HF is reviewed as well as methods, indications, effectiveness and complications.

Aortic stiffness and flow-mediated dilatation in normotensive offspring of parents with hypertension.

OBJECTIVES: Although hypertension has been shown to be one of the most important risk factors for atherosclerosis, data about the presence of subclinical atherosclerosis in normotensive offspring with parental history of hypertension are scarce. Accordingly, the current study was designated to evaluate flow-mediated dilatation and aortic stiffness, which are early signs of atherosclerosis in young subjects with parental history of hypertension. METHODS: A total of 140 [corrected] healthy, non-obese subjects in the age group of 18-22 years were included in this study and divided into two groups. The first group included 70 offspring of hypertensive parents and the second group included 70 offspring of normotensive parents as controls. In all subjects, endothelium-dependent and endothelium-independent vasodilatation of the brachial artery and aortic elastic parameters were investigated using high-resolution Doppler echocardiography. RESULTS: Offspring of hypertensive parents demonstrated higher values of aortic stiffness (7.1 plus or minus 1.88 and 6.42 plus or minus 1.56, respectively) but lower distensibility (9.47 plus or minus 1.33 and 11.8 plus or minus 3.36 square centimetres per dyne per 106) and flow-mediated dilatation (4.57 plus or minus 1.3 versus 6.34 plus or minus 0.83 percent, p equals 0.0001, respectively) than offspring of hypertensive parents. CONCLUSION: We observed blunted endothelium-dependent dilatation and aortic stiffness in offspring of hypertensive parents compared with offspring of normotensive [corrected] parents. This is evident in the absence of overt hypertension and other diseases, suggesting that parental history of hypertension is a risk for subclinical atherosclerosis and it may contribute to the progression to hypertension and overt atherosclerosis in later life.

[Evaluation of serum adiponectin levels in patients with obstructive sleep apnea syndrome]. / Tikayici uyku apnesi sendromlu hastalarin serum adiponektin düzeylerinin degerlendirilmesi.

OBJECTIVES: Serum adiponectin levels have been found to be lower in patients with obesity, hypertension, and coronary artery diseases. In this study, we aimed to evaluate serum adiponectin levels in patients with obstructive sleep apnea syndrome (OSAS) and to correlate these levels with the severity of OSAS. STUDY DESIGN: In 62 OSAS patients (39 males, 23 females) and 32 controls (23 males, 9 females) determined by polisomnography, serum adiponectin levels were analyzed by the ELISA method. Patients were classified as having either mild (apnea hypopnea index, AHI: 5-14), moderate (AHI: 15-29) or severe (AHI ≥30) OSAS, and controls were defined as AHI <5. Plasma fasting glucose, total cholesterol (TC), triglyceride (TG), and high (HDL-C) and low (LDL-C) density lipoprotein cholesterols were analyzed, and the results were compared between the groups. RESULTS: There was no significant difference in mean age (51.6±10.7 years for patients, 48.3±10.8 years for controls) or body mass index (32.9±6.0 kg/m2 for patients, 31.3±5.6 kg/m2 for controls, p>0.05) in our study population. There was no significant difference in the number of hypertensive, diabetics, or smokers between the patients and controls. While serum TC, TG, and HDL cholesterol levels were not significantly different between two groups, the serum adiponectin levels of patients (3.0±3.4 µg/dl) were significantly lower than those of the controls (5.2±5.2 µg/dl, p=0.01). While serum adiponectin levels showed a significantly negative correlation with AHI (r=-0.221, p=0.03), there was a significantly positive correlation with minimum and mean oxygen saturations (r=0.213, p=0.04 and r=0.205, p=0.05). CONCLUSION: Serum adiponectin levels were significantly lower in patients with OSAS, especially for those in the severe OSAS group. Serum adiponectin levels are related to the severity of OSAS and arterial oxygen saturation.

[A relationship between CRP, adiponectin and Gensini score in the patients with coronary artery disease]. / Koroner arter hastalarinda CRP, adiponektin ve Gensini skoru arasindaki iliski.

OBJECTIVE: We aimed to evaluate serum adiponectin and C-reactive protein (CRP) levels in the different groups of patients with angiographically defined coronary artery disease (CAD). METHODS: Overall 100 patients (80 males, 20 females) with CAD (≥ 50% stenosis) and 45 controls (25 males, 20 females) with normal coronary arteries were included in this cross-sectional observational study. Gensini score was used for evaluation of the severity of coronary lesions on the angiogram. A relationship between Gensini score and serum CRP and adiponectin levels was evaluated by a logistic regression analysis. RESULTS: Mean age of the patients (60.5±10.2 years) was significantly higher than of the controls (55.6±10.4 years, p=0.01). While serum adiponectin levels in CAD patients (2.1±1.2 µmg/dl) were significantly lower than in the controls (3.3±1.8 µmg/dl, p=0.01); serum CRP levels of the patients (2.8±1.5 mg/dl) were significantly higher than of the controls (0.9±0.4 mg/dl). Serum adiponectin and CRP levels were not significantly different between the CAD subgroups (p>0.05). Gensini score was related with serum CRP (odds ratio: 0.98, 95% CI: 1.05-1.35, p=0.01) and adiponectin levels (odds ratio: 1.15, 95% CI: 1.10-1.25, p=0.01) by a logistic regression analysis. CONCLUSION: While serum CRP levels are increased in CAD patients comparing with the controls; serum adiponectin levels are decreased significantly. Serum CRP and adiponectin levels are related to coronary lesions severity on the angiogram.

[Cardiovascular biomarkers in clinical practice of sleep apnea]. / Uyku apnesinin klinik uygulamasinda kardiyovasküler biyobelirteçler.

Obstructive sleep apnea syndrome (OSAS) leads to cardiovascular complications such as coronary artery disease, left/right ventricular hypertrophy and dysfunction, heart failure, systemic and pulmonary hypertension, arrhythmias and stroke; and these all cardiovascular complications increase morbidity and mortality of OSAS. However, Cheyne-Stokes respiration, central and obstructive apneas may occur in the patient with heart failure. Increased sympathetic activity by hypoxemia and endothelial dysfunction play a role in cardiovascular complications. Some cardiovascular biomarkers have a role in early diagnosis, treatment and prognosis. In the present review, some cardiovascular biomarkers such as serum C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukins, adiponectin, heart-type fatty acid binding protein (hFABP) and brain (B-type) natriuretic peptide (BNP), and their clinical importance were reviewed.

Impact of a well-organized collaborative team approach on mortality in patients with ST-segment elevation myocardial infarction.

OBJECTIVE: Fibrinolytic therapy remains a legitimate option for many patients presenting with acute ST-segment elevation myocardial infarction (STEMI). Shorter time- to- treatment for patients with STEMI administered fibrinolytic therapy has repeatedly been shown to reduce mortality. A well-organized collaborative team approach was implemented in April 2007. The purpose of this study was to examine the effect of implementing a well-organized collaborative team approach on the outcome in patients with acute STEMI treated with fibrinolysis. METHODS: Sociodemographic, clinical, laboratory, and time interval data were prospectively collected on 109 consecutive patients (the study group) and 155 patients from the years 2005-2007 (the control group) retrospectively. A single-phone call was made to discuss case. Emergency department evaluation was bypassed for definitive case. An electrocardiogram was faxed to the on-call cardiologist for suspected case. Door-to-needle times were calculated as medians. Mortality was assessed by reviewing records of all patients visiting outpatient clinic. For the rest, information was obtained over the phone. Median door-to-needle times were compared using Mann-Whitney U test. The Fisher's exact test was used to compare 6-month mortalities. RESULTS: Improvements were seen in door-to- needle times in the study group regardless of time of presentation (reduced from 59 minutes to 29 minutes during off hours) (reduced from 35 minutes to 18 minutes during regular hours) (p<0.0001). Mortality was significantly reduced in the study group (2 deaths, 1.8%) compared with the control group (12 deaths, 7.7%, p=0.048). CONCLUSION: The mortality of patients presenting with acute STEMI treated with fibrinolytic therapy was significantly reduced after optimal hospital organization.

[Heart failure and sleep apnea]. / Kalp yetersizligi ve uyku apnesi.

Sleep-disordered breathing is one of the important factors contributing to the development and/or progression of heart failure (HF). This condition is related to recurring attacks of apnea, hypopnea, and hyperpnea, sleep disruptions, arousals, intermittent hypoxemia, hypocapnia, and hypercapnia, and intrathoracic pressure changes. Obstructive sleep apnea (OSA) is characterized by recurrent upper airway obstruction (apnea and hypopnea), increased breathing effort against totally or partially occluded upper airway, and sleep disruptions. Cardiovascular consequences are the most serious complications of OSA and include acute myocardial infarction, heart failure, left/right ventricular dysfunction, arrhythmias, stroke, and systemic and pulmonary hypertension. Cheyne-Stokes respiration and central apneas may also occur in patients with HF. This article reviews the most recent information on the physiopathology, diagnosis, and treatment modalities of obstructive and central apneas in patients with HF.

Decreased plasma adiponectin concentrations in patients with syndrome X.

OBJECTIVE: The levels of adiponectin, an anti-atherogenic protein, are decreased in patients with coronary artery disease. Syndrome X is associated with endothelial dysfunction, which is a key feature in the evolution of atherosclerosis. We sought to determine whether serum adiponectin levels are decreased in patients with syndrome X. METHODS: Twenty-three syndrome X patients (14 men, 9 women) who presented with stable angina pectoris, had a positive non-invasive stress test or an abnormal myocardial perfusion scintigraphy single photon emission computed tomography (MPS SPECT) and a normal coronary angiogram, were included in our study, as were 17 asymptomatic healthy subjects (13 men, 4 women) with normal results from non-invasive stress testing. The serum adiponectin levels and lipid profiles of the patients and control subjects were determined with venous samples collected after a 12-hour fast. The results were analysed by a Mann Whitney U test. RESULTS: Mean age (54.1 +/- 11.8 y in patients and 59.8 +/- 9.6 y in control subjects, P > 0.05) and body mass index (28.0 +/- 3.3 in patients and 27.1 +/- 4.2 in control subjects, P > 0.05) did not differ between the two groups. Adiponectin levels in patients with syndrome X (1.5 +/- 1.1 microg/dl) were significantly lower than those in the control group (5.3 +/- 2.9 microg/dl, P < 0.0001). Serum total cholesterol (TCHOL), triglyceride (TG), LDL, and HDL-cholesterol levels did not differ between the two groups (P > 0.05). CONCLUSION: Serum adiponectin levels were lower in patients with syndrome X, and these low adiponectin concentrations may cause endothelial dysfunction. Thus, patients with a marked drop in adiponectin levels may be considered at high risk for future coronary events and may therefore benefit from additional pharmacological treatment.