Composite Autonomic Severity Score Research Articles

What is the minimum duration of head-up tilt necessary to detect orthostatic hypotension?

There is uncertainty as to the minimum duration of head-up tilt (HUT) needed to detect orthostatic hypotension (OH). The orthostatic duration has variably been recommended to be 1, 2, 3, and 5 minutes. The purpose of the current study was 1) to determine the minimum duration of HUT necessary to detect OH and 2) to identify different patterns of orthostatic blood pressure (BP) response in patients with OH. We evaluated the medical records of 66 consecutive patients (mean age 70.0+/-10.1 years; 64% male) seen at Mayo Clinic-Rochester from 2000-2001 who fulfilled the criteria for OH (systolic blood pressure [SBP] reduction > or = 20 mmHg within 3 minutes of HUT) during routine clinical autonomic studies. All patients completed an autonomic reflex screen with continuous monitoring of heart rate and BP during supine rest and 5 minutes of 70 degree HUT. Severity of autonomic deficits was quantified with the Composite Autonomic Severity Score (CASS). Overall, BP was the lowest at 1 minute with gradual and partial recovery over the following 4 minutes. Eighty-eight percent of patients (N=58) developed OH by 1 minute of HUT, with an additional 11% (N=7) developing OH by 2 minutes and the remaining 1% (N=1) developing OH by 3 minutes. We identified two broad patterns of SBP response to HUT. Forty-eight percent (N=32) of patients demonstrated an initial drop in SBP (> or = 20 mm Hg),which remained stable until tilt-back. Thirty-six percent (N=24) demonstrated an initial drop (> or = 20 mmHg) followed by a progressive decline in SBP until tilt-back. Repeated measures analysis of variance confirmed that the SBP change in response to HUT differed significantly among patients with a stable vs. progressive pattern [F(3,32)=25.1, p<0.001). Patients with the progressive pattern also had more severe adrenergic impairment on the CASS (p=0.03) and were more likely to have their tilt test terminated early (prior to 5 minutes) due to presyncope (p<0.0001) than patients with the stable pattern. One minute of HUT will detect OH in the great majority (88%) of patients and three minutes will detect the balance. Orthostatic stress beyond 2 minutes is necessary to detect the pattern of progressive OH. Since this group has more severe adrenergic deficits than the group with stable OH, we suggest that the progressive pattern is due to greater impairment of compensatory reflexes. Recognition of the group with progressive fall in BP is important since this group may be at greater risk of orthostatic syncope.

Evaluation of Orthostatic Hypotension: Relationship of a New Self-report Instrument to Laboratory-Based Measures

To compare measured autonomic deficits (composite autonomic severity score [CASS]) with a brief self-report scale we developed to measure severity of symptoms of orthostatic hypotension. Patients were recruited in 2 phases: from August to October 2002 and in April 2004. All patients underwent full evaluation in the autonomic laboratory, from which a CASS of autonomic deficits was derived. Patients also completed the 5-item self-report Orthostatic Grading Scale, which inquires about symptoms of orthostatic intolerance due to orthostatic hypotension (eg, severity, frequency, and interference with daily activities). Of 145 patients, 97 (67%) had orthostatic hypotension. The 5-item scale demonstrated strong internal consistency (coefficient alpha=.91). Patients with orthostatic hypotension had significantly higher scores on each questionnaire item and CASS subscores than those without orthostatic hypotension. The scale items correlated significantly with each of the CASS subscores, maximally with the CASS adrenergic subscore. Orthostatic hypotension is not the only cause of reduced orthostatic tolerance, and some patients may have orthostatic hypotension but be asymptomatic. Results of this study indicate that this 5-item questionnaire is a reliable and valid measure of the severity of symptoms of orthostatic hypotension and that it can supplement laboratory-based measures to provide a rapid, more complete clinical assessment. This questionnaire would also be useful as a brief screening device for orthostatic intolerance to aid physicians in identifying patients who may have orthostatic hypotension.

Autonomic Symptoms and Diabetic Neuropathy

The prevalence of autonomic symptoms and deficits in certain systems is known, but a comprehensive autonomic symptom profile in diabetes is not available. We aimed to estimate this using a laboratory evaluation of autonomic function and a validated self-report measure of autonomic symptoms in patients and matched control subjects from the population-based Rochester Diabetic Neuropathy Study. Participants included 231 patients with diabetes (type 1, n=83; type 2, n=148) and 245 healthy age-matched control subjects. We assessed symptoms using a validated self-report instrument (Autonomic Symptom Profile) and evaluated the severity and distribution of autonomic deficits (cardiovagal, sudomotor, adrenergic) with the objective, laboratory-based Composite Autonomic Severity Score (CASS). Autonomic symptoms were present more commonly in type 1 than in type 2 diabetes, with symptoms of orthostatic intolerance, secretomotor, urinary control, diarrhea, and sleep disturbance and pupillomotor, vasomotor, and erectile dysfunction significantly increased over healthy control subjects in type 2 diabetic patients. The prevalence of autonomic impairment was 54% in type 1 and 73% in type 2 diabetic patients. Severity of autonomic failure was mild overall (mean CASS 2.3; maximum 10), with orthostatic hypotension occurring in 8.4 and 7.4% of type 1 and 2 diabetic patients, respectively. Fourteen percent of patients had a CASS > or =5, indicating moderate to severe generalized autonomic failure. The correlation of symptoms with autonomic deficits (CASS) was better in type 1 than type 2 diabetic subjects and was weak overall. These findings indicate that autonomic symptoms and deficits are common in diabetes, but mild in severity, and that the correlation between symptom scores and deficits is overall weak in mild diabetic neuropathy, emphasizing the need to separately evaluate autonomic symptoms.