Akif Arslan

Effects of normal blood pressure, prehypertension, and hypertension on autonomic nervous system function

BACKGROUND Autonomic nervous system plays an important role in blood pressure (BP) regulation, and large proportion of patients with hypertension have increased sympathetic and decreased parasympathetic activity. Heart rate recovery (HRR) is a simple non-invasive measurement for investigating autonomic nervous system influence on the cardiovascular system; however, this methodology has not been used to evaluate autonomic nervous system in subjects with prehypertension (PHT). Accordingly, the present study was designed to evaluate HRR in subjects with PHT. METHODS AND RESULTS We measured HRR of 91 subjects with PHT, 44 patients with hypertension, and 53 normotensive healthy volunteers. HRR was significantly lower in the HT and PHT groups as compared to the control group (24.4 ± 5.7, 26.0 ± 8.4, 30.0 ± 8.7; hypertension, PHT, and control groups, respectively), but it did not significantly differ between HT and PHT groups. HRR was significantly and inversely correlated with age, systolic and diastolic BP, fasting and postprandial glucose level, waist circumference, total cholesterol, LDL cholesterol and non-HDL cholesterol, whereas exercise duration and METs were positively correlated with HRR. In multivariable analysis, we found that systolic BP, postprandial glucose level and exercise duration were independent predictors of lower HRR. CONCLUSIONS HRR, a non-invasive measurement analyzing the dysfunction in autonomic nervous system, was reduced in subjects with PHT as compared to normotensives, and the subjects with PHT had HRR as lower as patients with HT did. Our findings are supportive for the hypothesis that autonomic dysregulation is present in an early stage of essential hypertension.

Mean platelet volume is elevated in patients with myocardial infarction with normal coronary arteries, as in patients with myocardial infarction with obstructive coronary artery disease

Abstract Although the majority of cases of acute myocardial infarction are caused by atherosclerotic coronary artery disease (CAD), it can also occur in people with normal coronary arteries. One of the possible mechanisms causing myocardial infarction with normal coronary arteries (MINC) is transient occlusion of the infarct-related artery owing to platelet hyperactivity and thrombosis. Mean platelet volume (MPV), an indicator of platelet activation, has been shown to be elevated in patients with unstable angina and myocardial infarction in the setting of obstructive CAD. However, the value of MPV in patients with MINC is not known. The aim of this study was to assess the MPV in patients with MINC. We retrospectively studied 47 patients with MINC, 63 patients with myocardial infarction resulting from single coronary artery disease (MISC) and 55 control subjects. MPV values were recorded in all study patients and control subjects. The MPV values of patients with MINC and MISC were significantly higher than those of the control group (9.1±1.8 and 9.4±1.0 versus 8.3±1.4 fl; p<0.05 and p<0.001, respectively). There were no significant differences in MPV values between the MINC and MISC groups. We show for the first time that MPV is significantly higher in patients with MINC compared with control subjects. Concurring with previous studies, we also show that MPV is significantly higher in patients with MISC compared to control subjects.

Effects of prediabetes and diabetes on left ventricular and coronary microvascular functions

BACKGROUND Coronary flow reserve (CFR) provides independent prognostic information in diabetic patients with known or suspected coronary artery disease. However, there have been no substantial data to evaluate CFR in prediabetics. Accordingly, we aimed to evaluate CFR in subjects with prediabetes using second harmonic transthoracic Doppler echocardiography. METHODS AND RESULTS We measured CFR of 65 subjects with prediabetes, 45 patients with overt type 2 diabetes, and 43 sex and age matched normoglycemic healthy subjects with normal glucose tolerance. Ages, gender, existence of hypertension or hypercholesterolemia, smoking status were similar among the groups. CFR was significantly lower in diabetics (2.15 ± 0.39) than in prediabetics (2.39 ± 0.45) and controls (2.75 ± 0.35); in addition, it was significantly lower in prediabetics than controls. Only 2 (5%) of control subjects had abnormal CFR (<2) but 11 (17%) prediabetic subjects and 19 (42%) diabetic patients had abnormal CFR. We found that only age (β=-0.31, P<0.01) and presence of the diabetes (β=-0.57, P<0.01) were significant predictors of lower CFR in a multivariable model that adjusted for other variables. CFR was significantly and inversely correlated with age (r=-0.15, P=0.04), fasting glucose level (r=-0.27, P=0.001), postprandial glucose level (r=0.43, P<0.001), hemoglobin A1C level (r=-0.34, P<0.001), LDL cholesterol level (r=0.22, P=0.009), mitral A velocity (r=-0.27, P=0.001) and Tei index (r=-0.19, P=0.02), whereas mitral E/A ratio, mitral Em (r=0.18, P=0.02), mitral Em/Am ratio (r=0.23, P=0.004) were significantly and positively correlated with CFR. CONCLUSION CFR is impaired in subjects with prediabetics, but this impairment is not as severe as that in diabetics.

Mean platelet volume is associated with culprit lesion severity and cardiac events in acute coronary syndromes without ST elevation.

We investigated the association of mean platelet volume (MPV) with culprit lesion severity and major cardiac outcomes (MCOs) in patients with acute coronary syndrome (ACS) with non-ST elevation (NSTE). This study included 344 patients with NSTE-ACS who had significant coronary stenosis at least 50%. They were divided into high MPV group (n = 109, upper tertile >9.9 fl) and low MPV group (n = 235, lower and mid tertile ⩽9.9 fl) according to MPV values on admission. They were followed up for MCOs during 12 months. MCO consisted of the composite end-point of cardiac death, myocardial infarction (MI), recurrent angina or hospitalization. High MPV was independently associated with NSTE-MI [odds ratio (OR) 4.24, 95% confidence interval (CI) 2.52–7.15, P = 0.001] and severe culprit stenosis (≥80%) (OR 4.05, 95% CI 2.39–6.83, P = 0.001). MPV of 9.9 fl was predictive of severe culprit stenosis with a sensitivity of 73% and specificity of 77% (P < 0.001). At 12 months, MCO rate was higher in high MPV group than low MPV group (39 vs. 26%; P = 0.016). This difference resulted from death (6.4 vs. 2.1; P = 0.06) and recurrent angina (16.5 vs. 8.9%; P = 0.045). The MCO-free survival was worse in patients with high MPV than those with low MPV (61 vs. 74%; P = 0.01). In Cox regression analysis, high MPV remained an independent predictor of MCO (hazard ratio 1.52, 95% CI 1.01–2.29, P = 0.04) after adjusting for baseline characteristics. Elevated MPV was independently associated with NSTE-MI presentation and severity of culprit stenosis in NSTE-ACS patients. Moreover, MPV greater than 9.9 fl was predictive of a 12-month MCO.

Mean platelet volume is increased in infective endocarditis and decreases after treatment.

Objectives: The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with infective endocarditis. Subjects and Methods: Twenty-nine patients with infective endocarditis and 29 healthy subjects were studied. Plasma MPV values in patients and control subjects were measured on admission and after 2 weeks of specific treatment of infective endocarditis. Results: The MPV was significantly higher among patients with infective endocarditis when compared with the control group (9.86 ± 1.1 vs. 8.0 ± 1.0 fl, respectively; p < 0.01). The MPV values of patients with infective endocarditis decreased significantly after treatment from 9.86 ± 1.1 to 7.86 ± 1.0 fl (p < 0.01). Total platelet counts increased significantly after treatment from 193.4 ± 96.5 × 109 to 243.7 ± 92.4 × 109 (p = 0.04). Conclusion: MPV values were higher in patients with infective endocarditis and decreased significantly after treatment. Elevated MPV values indicate that patients with infective endocarditis have increased platelet activation and infective endocarditis treatment decreases this platelet activation by decreasing MPV.

Increased Mean Platelet Volume in Patients With Aortic Stenosis

Background: Systemic thromboembolism is a serious complication in patients with aortic stenosis (AS). Previous studies have demonstrated that platelet activation occurs in patients with AS. The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with AS. Patients and Methods: The study group consisted of 43 patients with AS. An age-, gender-, and body mass index−matched control group consisted of 35 healthy volunteers. All patients and control participants underwent echocardiographic examination. We measured the serum MPV values in patients and control participants. Results: Mean platelet volume was significantly higher among patients with AS when compared with the control group (8.7 ± 1.0 vs 7.9 ± 0.9 fL, respectively; P = .001). Conclusion: We have shown that MPV was significantly elevated in patients with AS compared to control participant.

Increased Mean Platelet Volume in Familial Hypercholesterolemia.

Familial hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism and increases the risk of premature cardiovascular diseases. In patients with FH, platelet function may be activated; however, the extent of this activation and its etiology are unclear. We aimed to evaluate the mean platelet volume (MPV), a marker of platelet activation, in patients with FH. The study group consisted of 164 patients with FH and 160 control patients. Controls were matched for age, gender, hypertension, and smoking. The MPV was significantly higher in patients with FH than in controls (9.2 ± 0.4 vs 7.9 ± 0.6 fL, respectively; P < .001). Platelet count was significantly lower among patients with FH when compared to control patients (259 ± 51 vs 272 ± 56 × 103/L, respectively; P = .03). In linear regression analysis, MPV was independently associated only with total cholesterol (β = .6, 95% confidence interval: 0.004-0.008, P < .001). We have shown that MPV was increased in patients with FH and that it was independently associated with total cholesterol level.

The effects of good glycaemic control on left ventricular and coronary endothelial functions in patients with poorly controlled Type 2 diabetes mellitus

Diabetics are at risk for developing overt heart failure and subclinical left ventricular (LV) dysfunction. Also, impaired coronary flow reserve (CFR) reflecting coronary microvascular dysfunction is common in diabetics. However, no substantial data regarding the effects of good glycaemic control on subclinical LV dysfunction and CFR are available.

Increased Mean Platelet Volume in Hypertrophic Cardiomyopathy

Thromboembolic events may be seen in patients with hypertrophic cardiomyopathy (HCM). We investigated the mean platelet volume (MPV), an indicator of platelet activation in patients with HCM. This study included 112 patients with HCM, in which 40 were patients with hypertrophic obstructive cardiomyopathy (HOCM), and 106 were control participants. The MPV was significantly higher in patients with HCM than in controls (9.1 ± 0.3 vs 7.9 ± 0.3 fL, P = .01). In the subgroup analyses, MPV was also higher in patients with HOCM compared to those with hypertrophic nonobstructive cardiomyopathy (HNCM; 9.3 ± 0.3 vs 9.0 ± 0.2 fL, P = .01). Similarly, patients with HNCM had higher MPV values than controls (9.0 ± 0.2 vs 7.9 ± 0.3 fL, P = .01). The MPV was significantly and positively correlated with left ventricular outflow tract (LVOT) obstruction (r = .42, P = .001) and septal thickness (r =.62, P = .001). In linear regression analysis, MPV was independently associated only with septal thickness (β = .07, 95% confidence interval: 0.04-0.09, P = .001). The MPV can be elevated in patients with HCM regardless of the obstruction of LVOT and may be associated with the severity of septal thickness.

Echocardiographic predictors of progression from prehypertension to hypertension.

Background: Prehypertension (PHT) was recently introduced by replacing former categories of high–normal and above-optimal blood pressure (BP). The rationale for redefining this new category was to emphasize the excess cardiovascular risk associated with BP in this range and to focus high risk for developing hypertension (HT). However, no clear definite markers to identify prehypertensive patients at high risk of progressing to HT have been established yet. Accordingly, we aimed to establish echocardiographic predictors of progression from PHT to HT. Methods and results: The study population consisted of 98 eligible prehypertensive patients. All patients underwent echocardiographic examination including coronary flow reserve (CFR) at baseline. Twenty-nine (30%) patients developed HT during the 3-year follow-up period. Creatinine level, left ventricular mass index (LVMI), mitral Em and Em/Am had a trend towards a significant crude odds ratio (OR) for the development of HT; however, only baseline SBP [OR = 1.18, 95% confidence interval (CI)  = 1.06–1.31; P = 0.002), having metabolic syndrome (OR = 3.75, 95% CI = 1.43–9.78; P = 0.007), high-density lipoprotein (HDL) cholesterol (OR = 0.92, 95% CI = 0.86–0.98; P = 0.01), presence of microalbuminuria (OR = 3.53, 95% CI = 1.11–11.2; P = 0.03) and CFR (OR = 0.65, 95% CI = 0.53–0.77; P = 0.02) were significant independent predictors of progression of PHT into HT. The best cutoff value of CFR to predict incident HT was 1.98 with 94% sensitivity and 79% specificity. Conclusion: This prospective study suggested that baseline SBP, having metabolic syndrome, HDL cholesterol level, presence of microalbuminuria and CFR reflecting coronary microvascular function, but not left ventricular diastolic function parameters, were significant independent markers to identify participants with PHT at high risk for incident HT.