1. Aetna considers tilt table testing, alone or in combination with administration of provocative agents (e.g., isoproterenol), medically necessary for the evaluation of members with recurrent unexplained syncope who have an inconclusive history and physical examination, as well as negative non-invasive tests of cardiac structure and function.

2. Aetna considers the use of tilt table testing experimental and investigational for all other indications, including any of the following (not an all inclusive list) because there is little support in the peer-reviewed medical literature for tilt table testing for these indications:

See also CPB 0369 - Chronic Fatigue Syndrome.

There is sufficient evidence that tilt table testing, with or without isoproterenol, is safe and effective as a diagnostic tool for the evaluation of patients with recurrent unexplained syncope.  The reported sensitivity, specificity, and reproducibility of tilt table testing ranged from 65 to 87 %, 55 to 96 %, and 71 to 88 %, respectively.  This procedure helps to identify a largely benign disorder and, indirectly, exclude other possibly life-threatening conditions.  Tilt table testing performed early in the evaluation may obviate extensive and expensive tests such as intra-cardiac electrophysiological studies, CAT scan, and MRI of the brain.  In contrast, there is insufficient evidence that tilt table testing following intravenous infusion of metoprolol can accurately predict the effectiveness of oral metoprolol therapy in treating patients with recurrent unexplained syncope.  This procedure has not been shown to provide any additional information than would have been obtained from a trial of oral therapy.

There is inadequate evidence of the effectiveness of tilt-table testing for identifying chronic fatigue syndrome (CFS) patients who would respond to medications to increase their blood pressure.  Several case series have shown that patients with known CFS frequently have abnormal responses to tilt-table testing, and CFS patients in these series also frequently appear to respond to anti-hypotensive medications commonly used in patients with neurally mediated hypotension.  These case studies fail to demonstrate, however, any value of tilt-table testing in distinguishing CFS patients that would respond to these medications from those who would not.

Straus and colleagues (2009) stated that Chiari I malformation (CM1) is characterized by impaired cerebrospinal fluid flow through the foramen magnum.  Dysfunctional autonomic cardiovascular regulation may result in syncope, which may be the primary presenting symptom of CM1 (a syndrome termed Chiari drop attack).  It has been postulated that Chiari drop attack is secondary to dysautonomia caused by hind-brain compression.  These researchers studied patients with Chiari drop attacks who had negative work-ups for cardiac syncope, followed by tilt table testing and subsequent surgical decompression.  They reported test results and clinical outcomes following CM1 decompression.  A total of 10 patients met the inclusion criteria: 5 patients had positive and 5 negative tilt table tests.  Following decompression, 7 had symptomatic improvement or resolution and 3 failed to improve.  The sensitivity and specificity of the tilt table test for detecting clinical improvement with surgical decompression was 43 % and 33 %, respectively.  Tilt table testing had 40 % accuracy in predicting clinical response to decompression.  The authors concluded that in this short series, surgical decompression of CM1 has a high success rate (70 %) for patients with Chiari drop attacks.  Moreover, tilt table testing has poor predictive value in judging the clinical response to surgical decompression and is not a useful test to guide surgical decision-making.

Uno and colleagues (2009) noted that although it is well known that autonomic dysfunction in obstructive sleep apnea syndrome (OSAS) is associated with hypertension, its relationship to hypotension and orthostatic dysregulation is still unclear.  These investigators examined the response of blood pressure (BP) and cardiovascular autonomic function to head-up tilt (HUT) test in patients with OSAS.  In this study, a total of 14 patients (mean age of 65 +/- 2 years old, male/female: 11/3) with diagnosed OSAS by over-night polysomnography and 84 healthy subjects (mean age of 62 +/- 1 years old, male/female: 46/38) underwent HUT test (from 5 to 10 mins at 45 degrees).  Autonomic functions were evaluated by spectrum analysis of BP and heart rate variability.  In healthy subjects, systolic BP was unchanged by HUT test due to the enhancement of sympathetic nerve activity and the inhibition of parasympathetic nerve activity.  In contrast, autonomic responses were unchanged and systolic BP tended to be decreased by HUT test in OSAS patients.  The authors concluded that the findings of this study suggested that baroreflex function is impaired in patients with OSAS.  Furthermore, HUT test with spectrum analysis may be useful to evaluate autonomic functions in OSAS patients.

Oliveira et al (2009) stated that the autonomic nervous system (ANS) is known to be an important modulator in the pathogenesis of paroxysmal atrial fibrillation (PAF).  Changes in ANS control of heart rate variability (HRV) occur during orthostatism to maintain cardiovascular homeostasis.  Wavelet transform has emerged as a useful tool that provides time-frequency decomposition of the signal under investigation, enabling intermittent components of transient phenomena to be analyzed.  These investigators studied HRV during HUT with wavelet transform analysis in PAF patients and healthy individuals (normals).  A total of 21 patients with PAF (8 men; age of 58 +/- 14 yrs) were examined and compared with 21 normals (7 men, age of 48 +/- 12 yrs).  After a supine resting period, all subjects underwent passive HUT (60 degrees) while in sinus rhythm.  Continuous monitoring of electroencephalography and BP was carried out.  Acute changes in RR-intervals were assessed by wavelet analysis and low-frequency power (LF: 0.04 to 0.15 Hz), high-frequency power (HF: 0.15 to 0.60 Hz) and LF/HF (sympatho-vagal) were calculated for (i) the last 2 mins of the supine period; (ii) the 15 secs of tilting movement (TM); and (iii) the 1st (TT1) and 2nd (TT2) min of HUT.  Data were expressed as means +/- SEM.  Baseline and HUT RR-intervals were similar for the 2 groups.  Supine basal BP was also similar for the 2 groups, with a sustained increase in PAF patients, and a decrease followed by an increase and then recovery in normals.  Basal LF, HF and LF/ HF values in PAF patients were 632 +/- 162 ms2, 534 +/- 231 ms2 and 1.95 +/- 0.39, respectively, and 1,058 +/- 223 ms2, 789 +/- 244 ms2 and 2.4 +/- 0.36, respectively, in normals (p = NS).  During TM, LF, HF and LF/HF values for PAF patients were 747 +/- 277 ms2, 387 +/- 94 ms2 and 2.9 +/- 0.6, respectively, and 1316 +/- 315 ms2, 698 +/- 148 ms2 and 2.8 +/- 0.6, respectively, in normals (p < 0.05 for LF and HF).  During TF1, LF, HF and LF/ HF values for PAF patients were 1,243 +/- 432 ms2, 302 +/- 88 ms2 and 7.7 +/- 2.4, respectively, and 1,992 +/- 398 ms2, 333 +/- 76 ms2 and 7.8 +/- 0.98, respectively, for normals (p < 0.05 for LF).  During TF2, LF, HF and LF/HF values for PAF patients were 871 +/- 256 ms2, 242 +/- 51 ms2 and 4.7 +/- 0.9, respectively, and 1263 +/- 335 ms2, 317 +/- 108 ms2 and 8.6 +/- 0.68, respectively, for normals (p < 0.05 for LF/HF).  The dynamic profile of HRV showed that LF and HF values in PAF patients did not change significantly during TM or TT2, and LF/HF did not change during TM but increased in TT1 and TT2.  The authors concluded that patients with PAF present alterations in HRV during orthostatism, with decreased LF and HF power during TM, without significant variations during the first minutes of HUT.  These findings suggested that wavelet transform analysis may provide new insights when assessing autonomic heart regulation and highlight the presence of ANS disturbances in PAF.  The findings of these small preliminary studies need to be validated by well-designed studies.

Riley and Chelimsky (2003) stated that formal laboratory testing of autonomic function is reported to distinguish between patients with Parkinson's disease (PD) and those with multiple system atrophy (MSA), but such studies segregated patients according to clinical criteria that select those with autonomic dysfunction for the MSA category.  These researchers attempted to characterize the profiles of autonomic disturbances in patients in whom the diagnosis of PD or MSA used criteria other than autonomic dysfunction.  A total of 47 patients with parkinsonism and autonomic symptoms who had undergone autonomic laboratory testing were identified and their case records reviewed for non-autonomic features.  They were classified clinically into 3 diagnostic groups: (i) PD (n = 19), MSA (n = 14), and uncertain (n = 14).  The performance of the patients with PD was compared with that of the MSA patients on 5 autonomic tests: (i) R-R interval variations during deep breathing, (ii) heart rate changes with the Valsalva maneuvre, (iii) tilt table testing, (iv) the sudomotor axon reflex test, and (v) thermoregulatory sweat testing.  None of the tests distinguished one group from the other with any statistical significance, alone or in combination.  Parkinson's disease and MSA patients showed similar patterns of autonomic dysfunction on formal testing of cardiac sympathetic and parasympathetic, vasomotor, and central and peripheral sudomotor functions.  The authors concluded that these findings supported the clinical observation that PD is often indistinguishable from MSA when it involves the autonomic nervous system.  The clinical combination of parkinsonism and dysautonomia is as likely to be caused by PD as by MSA.  Current clinical criteria for PD and MSA that direct patients with dysautonomia into the MSA group may be inappropriate.

Reimann et al (2010) stated that differential diagnosis of parkinsonian syndromes is a major challenge in movement disorders.  Dysautonomia is a common feature but may vary in clinical severity and onset.  These investigators attempted to find a pattern of autonomic abnormalities discriminative for patients with different parkinsonian syndromes.  The cross-sectional study included 38 patients with MSA, 32 patients with progressive supranuclear palsy (PSP), 26 patients with idiopathic PD (IPD), and 27 age-matched healthy controls.  Autonomic symptoms were evaluated by a standardized questionnaire.  The performance of patients and controls was compared on 5 autonomic function tests: (i) deep breathing, (ii) Valsalva maneuvre, (iii) tilt-table testing, (iv) sympathetic skin response, (v) pupillography, as well as 24-hr ambulatory BP monitoring (ABPM).  Disease severity was significantly lower in IPD than PSP and MSA.  Except for pupillography, none of the laboratory autonomic tests distinguished one patient group from the other alone or in combination.  The same was observed on the questionnaire.  Receiver operating characteristic curve revealed discriminating performance of pupil diameter in darkness and nocturnal BP change.  The composite score of urogenital and vasomotor domains significantly distinguished MSA from IPD patients but not from PSP.  These findings supported the observation that even mild IPD is frequently indistinguishable from more severe MSA and PSP.  Thus, clinical combination of motor and non-motor symptoms does not exclusively point at MSA.  Pupillography, ABPM and the questionnaire may assist in delineating the 3 syndromes when applied in combination.