Waist circumference is the best index for obesity-related cardiovascular disease risk in individuals with spinal cord injury

Obesity is an important identifier of cardiovascular disease (CVD) risk, but is challenging to determine accurately in individuals with spinal cord injury (SCI). Body mass index (BMI) is used worldwide as a simple indicator of obesity, but is difficult to measure in individuals with SCI. Furthermore, standard BMI cutoffs underestimate obesity in this population. Therefore, we aimed to identify the best marker of obesity in individuals with SCI, considering both practicality, and ability to detect adiposity and CVD risk. Five anthropometric measures were evaluated: BMI; waist circumference (WC); waist-To-height ratio (WHtR); waist-To-hip ratio; and neck circumference. We evaluated relationships between these measures and abdominal and total body-fat percentage, seven cardiovascular metabolic risk factors (fasting insulin, glucose, glucose tolerance, triglycerides, high-density lipoprotein, low-density lipoprotein, and total cholesterol), and the Framingham risk score. BMI, WC, and WHtR were correlated with abdominal fat percentage. WC and WHtR were correlated with five metabolic risk factors as well as the Framingham risk score. WC is a more practical measure for an SCI population. The optimal cutoff for identifying adverse CVD risk in individuals with SCI was identified as WC ≥94 cm, with 100% sensitivity and 79% specificity. We propose that WC is a simple, more sensitive alternative to BMI in this population that is easy to use in multiple settings. The cutoff provides a simple tool to predict adverse CVD risk profiles that can be used to guide risk management, as well as as a practical aid for individuals with SCI to maintain a healthy body composition. © Copyright 2014, Mary Ann Liebert, Inc. 2014

Optimal scaling of weight and waist circumference to height for adiposity and cardiovascular disease risk in individuals with spinal cord injury

Study design: Observational cross-sectional study. Objectives: Body mass index (BMI), measured as a ratio of weight (Wt) to the square of height (Wt/H

R-R interval-blood pressure interaction in subjects with different tolerances to orthostatic stress

In addition to the gain, the time delay in the input–output response in a feedback system is crucial for the maintenance of its stability. Patients with posturally related (vasovagal) syncope have inadequate control of blood pressure and one possible explanation for this could be prolonged latency of the baroreflex. We studied 14 patients with histories of syncope and poor orthostatic tolerance (assessed by a progressive orthostatic stress test) and 16 healthy controls. We performed spontaneous sequence analysis of the fluctuations of R–R period (ECG) and systolic arterial pressure (SAP, Finapres) recorded during a 20 min supine period and during 20 min 60 deg head-up tilt (HUT). The baroreflex latency was determined by identifying the lag between the changes in SAP and in R–R interval from which the highest correlation coefficient was obtained. During the supine period, 74% of sequences in control subjects and 54% in patients occurred with zero beats of delay (i.e. R–R interval changed within the same R–R interval). The remaining sequences occurred with delays of up to four beats. HUT shifted the baroreflex delay to be approximately one heartbeat slower and again patients showed more sequences with prolonged response. The delay in heartbeats was transformed into delay in time. In control subjects, 75% of baroreflex responses occurred within 1 s. In patients, 75% of baroreflex responses took more than 2 s to occur. The results showed that syncopal patients with poor orthostatic tolerance have increased baroreflex latency. This may lead to instability and inadequate blood pressure control and may predispose to vasovagal syncope

Diagnosis and treatment of orthostatic hypotension

Orthostatic hypotension is an unusually large decrease in blood pressure on standing that increases the risk of adverse outcomes even when asymptomatic. Improvements in haemodynamic profiling with continuous blood pressure measurements have uncovered four major subtypes: initial orthostatic hypotension, delayed blood pressure recovery, classic orthostatic hypotension, and delayed orthostatic hypotension. Clinical presentations are varied and range from cognitive slowing with hypotensive unawareness or unexplained falls to classic presyncope and syncope. Establishing whether symptoms are due to orthostatic hypotension requires careful history taking, a thorough physical examination, and supine and upright blood pressure measurements. Management and prognosis vary according to the underlying cause, with the main distinction being whether orthostatic hypotension is neurogenic or non-neurogenic. Neurogenic orthostatic hypotension might be the earliest clinical manifestation of Parkinson's disease or related synucleinopathies, and often coincides with supine hypertension. The emerging variety of clinical presentations advocates a stepwise, individualised, and primarily non-pharmacological approach to the management of orthostatic hypotension. Such an approach could include the cessation of blood pressure lowering drugs, adoption of lifestyle measures (eg, counterpressure manoeuvres), and treatment with pharmacological agents in selected cases.Paroxysmal Cerebral Disorder