[Sympathetic nerve activity in essential hypertension. New pathophysiologic aspects]

Investigating the differences of body mass index and waist circumference in the follow-up assessment of patients to cardiac rehabilitation with acute coronary syndrome

Obesity management is a key point during cardiac rehabilitation. The effect of new index, waist circumference (WC), in the obesity management of cardiac rehabilitation is not clear yet. Therefore, our study compared the WC index to the body mass index (BMI) in the evaluation of obesity management for the patients with acute coronary syndrome (ACS) in a well-designed cardiac rehabilitation program (CRP). Totally 61 patients were enrolled into our study between October 2013 and January 2014 in our hospital. All these patients were requested to participate in the CRP actively for 6 months. We collected the BMI, WC, vital signs, fasting blood levels, the results from a sub-maximal exercise treadmill test (ETT) and ultrasonic cardiogram (UCG) through a follow-up visit conducted every 1, 3, and 6 months. We used two-tailed Pearson's test and linear regression to analyze the data from our experiment. Our results show that the grouping of obese individuals based on the WC results in the WC being significantly associated with high-density lipoprotein cholesterol (HDL_C), inter-ventricular septal thickness at diastole (IVSd) and left ventricular posterior wall at diastole (LVPwd) after 1 and 3 months of the CRP (HDL_C after1 month of CRP: r = -0.292, P = 0.022; HDL_C after 3 months of CRP: r = -0.289, P = 0.024; IVSd after1 month of CRP: r = 0.451, P = 0.004; IVSd after 3 months of CRP: r = 0.304, P = 0.035; LVPwd after1 month of CRP: r = 0.468, P = 0.002; LVPwd after 3 months of CRP: r = 0.290, P = 0.045). However, no similar regular associations were found when obesity was stratified using the BMI. In other words, WC could be better than the BMI for reflecting the cardiac status. In conclusion, obesity management using WC can benefit the clinical evaluation, diagnosis, treatment, prevention, and prognosis of obese individuals of ACS when participating in the CRP.

Treating resistant hypertension: role of renal denervation

Arterial hypertension is the most prevalent risk factor associated with increased cardiovascular morbidity and mortality. Although pharmacological treatment is generally well tolerated, 5%–20% of patients with hypertension are resistant to medical therapy, which is defined as blood pressure above goal (>140/90 mmHg in general; >130–139/80–85 mmHg in patients with diabetes mellitus; >130/80 mmHg in patients with chronic kidney disease) despite treatment with ≥3 antihypertensive drugs of different classes, including a diuretic, at optimal doses. These patients are at significantly higher risk for cardiovascular events, in particular stroke, myocardial infarction, and heart failure, as compared with patients with nonresistant hypertension. The etiology of resistant hypertension is multifactorial and a number of risk factors have been identified. In addition, resistant hypertension might be due to secondary causes such as primary aldosteronism, chronic kidney disease, renal artery stenosis, or obstructive sleep apnea. To identify patients with resistant hypertension, the following must be excluded: pseudo-resistance, which might be due to nonadherence to medical treatment; white-coat effect; and inaccurate measurement technique. Activation of the sympathetic nervous system contributes to the development and maintenance of hypertension by increasing renal renin release, decreasing renal blood flow, and enhancing tubular sodium retention. Catheter-based renal denervation (RDN) is a novel technique specifically targeting renal sympathetic nerves. Clinical trials have demonstrated that RDN significantly reduces blood pressure in patients with resistant hypertension. Experimental studies and small clinical studies indicate that RDN might also have beneficial effects in other diseases and comorbidities, characterized by increased sympathetic activity, such as left ventricular hypertrophy, heart failure, metabolic syndrome and hyperinsulinemia, atrial fibrillation, obstructive sleep apnea, and chronic kidney disease. Further controlled studies are required to investigate the role of RDN beyond blood pressure control.