Transvascular autonomic modulation: a modified balloon angioplasty technique for the treatment of autonomic dysfunction in multiple sclerosis patients.

PURPOSE: To describe the use of transvascular autonomic modulation (TVAM) to improve cardiovascular autonomic nervous system (ANS) dysfunction in multiple sclerosis (MS) patients, comparing the safety and efficacy of this modified technique with traditional balloon angioplasty.
METHODS: Twenty-one MS patients (11 men; mean age 48.7±13.0 years) who presented with symptoms of cardiovascular ANS dysfunction underwent TVAM. These patients were compared with age/sex-matched MS patients (10 men; 49.3±11.1 years) in the same stages of the disease who presented with chronic cerebrospinal venous insufficiency (CCSVI) and who underwent venous balloon angioplasty. TVAM involved the coupling of balloon angioplasty of the internal jugular veins with the application of external manual compression and dilation of the azygos and renal veins; unlike traditional angioplasty for CCSVI, which treats only abnormal veins (≥50% stenosis or static valve), all targeted vessels were treated with TVAM regardless of the presence of an abnormality. The effect of TVAM on ANS function was indicated by determining heart rate variability based on the electrocardiographic R-R interval lengths using vector analysis to derive the mean circular resultant (MCR) and the expiration/inspiration (E/I) ratio, the Valsalva ratio, and the 30:15 postural ratio at 24 hours after intervention.
RESULTS: Left renal vein compression was common among the TVAM patients and resulted in ≥50% luminal compromise in 10 of 21 patients. Azygos vein abnormalities (a static valve) were identified in 5 patients. Overall, 18 patients met the diagnostic criteria for CCSVI with at least one lesion >50%, but only 10 lesions were considered treatable by traditional balloon angioplasty. After intervention, the R-R interval values, including the 30:15 postural ratio (p=0.01), the MCR (p=0.1), and E/I ratio (p=0.1), were higher for the TVAM patients compared to the control group. The safety profile of the TVAM procedure was similar to that of traditional balloon angioplasty.
CONCLUSION: The combination of balloon angioplasty of anatomically normal veins coupled with external compression during dilation of these veins can improve indicators of ANS dysfunction. The safety and efficacy of TVAM in MS patients observed in this pilot study is encouraging, paving the way for the treatment of dysautonomia in pathological states other than MS. Further studies should investigate TVAM in a larger MS cohort.