Hemodynamics during the 10-minute NASA Lean Test: evidence of circulatory decompensation in a subset of ME/CFS patients by Jihyun Lee, Suzanne D Vernon, Patricia Jeys, Weam Ali, Andrea Campos, Derya Unutmaz, Brayden Yellman, Lucinda Bateman in J Transl Med. 2020 Aug 15;18(1):314 [doi: 10.1186/s12967-020-02481-y]
Lightheadedness, fatigue, weakness, heart palpitations, cognitive dysfunction, muscle pain, and exercise intolerance are some of the symptoms of orthostatic intolerance (OI). There is substantial comorbidity of OI in ME/CFS (Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome). The 10-minute NASA Lean Test (NLT) is a simple, point-of-care method that can aid ME/CFS diagnosis and guide management and treatment of OI. The objective of this study was to understand the hemodynamic changes that occur in ME/CFS patients during the 10-minute NLT.
A total of 150 ME/CFS patients and 75 age, gender and race matched healthy controls (HCs) were enrolled. We recruited 75 ME/CFS patients who had been sick for less than 4 years (< 4 ME/CFS) and 75 ME/CFS patients sick for more than 10 years (> 10 ME/CFS). The 10-minute NLT involves measurement of blood pressure and heart rate while resting supine and every minute for 10 min while standing with shoulder-blades on the wall for a relaxed stance. Spontaneously reported symptoms are recorded during the test. ANOVA and regression analysis were used to test for differences and relationships in hemodynamics, symptoms and upright activity between groups.
At least 5 min of the 10-minute NLT were required to detect hemodynamic changes. The < 4 ME/CFS group had significantly higher heart rate and abnormally narrowed pulse pressure compared to > 10 ME/CFS and HCs. The < 4 ME/CFS group experienced significantly more OI symptoms compared to > 10 ME/CFS and HCs. The circulatory decompensation observed in the < 4 ME/CFS group was not related to age or medication use.
Circulatory decompensation characterized by increased heart rate and abnormally narrow pulse pressure was identified in a subgroup of ME/CFS patients who have been sick for < 4 years. This suggests inadequate ventricular filling from low venous pressure. The 10-minute NLT can be used to diagnose and treat the circulatory decompensation in this newly recognized subgroup of ME/CFS patients.
The > 10 ME/CFS group had less pronounced hemodynamic changes during the NLT possibly from adaptation and compensation that occurs over time. The 10-minute NLT is a simple and clinically useful point-of-care method that can be used for early diagnosis of ME/CFS and help guide OI treatment.
While it isn’t entirely clear why the > 10 ME/CFS group appear to tolerate the orthostatic stress better than < 4 ME/CFS in terms of a dramatic drop in pulse pressure, that does not prove they aren’t experiencing a drop in cerebral perfusion. It is possible that after many years of ME/CFS illness there is gradual adaptation of the circulatory stress response to upright posture. That may also explain why the > 10 ME/CFS had the highest rise in SBP during the 10-minute NLT. There is also an age difference between the < 4 and > 10 ME/CFS groups of about 5–6 years which might also explain the higher SBP response in the > 10 ME/CFS subgroup. A very important recently published study demonstrated that cerebral blood flow is reduced in ME/CFS during head-up tilt testing even in the absence of hypotension or tachycardia . This is consistent with our findings and may explain why ME/CFS patients were not much more likely to meet standard criteria for POTS or OH than the HCs, even though they still became more symptomatic during the 10-minute NLT.
Health Rising blog post: NASA Lean test, an easy way to diagnose Orthostatic Intolerance in ME/CFS, Fibromyalgia and POTS, by Cort Johnson