Comparison of the head-up tilt test and the 10-minute NASA lean test for assessing blood pressure and heart rate responses in young individuals with postacute COVID-19 syndrome.

Background: Individuals with postacute COVID-19 syndrome (PACS) typically exhibit abnormal hemodynamic responses during upright positioning, including orthostatic hypotension and postural orthostatic tachycardia syndrome. The 10-minute NASA lean test (NLT) has been suggested for this condition. However, no comparative study with the head-up tilt table test (HUTT) has been conducted. This study aimed to compare blood pressure and heart rate responses during the 10-minute duration of NLT and HUTT.

Methods: Eighty young individuals (aged 22.0 ± 3.1 years) with PACS underwent both tests, with a 30-minute interval between tests. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were measured every minute, and the differences between supine and upright positions were analyzed.

Results: There were no significant differences in SBP changes between HUTT and NLT (-7.8 ± 6.2 vs. -7.1 ± 7.5 mmHg) with a mean difference of -0.7 ± 9.0 mmHg. However, DBP changes were significantly lower in HUTT compared to NLT (-0.9 ± 6.4 vs. 1.5 ± 6.9 mmHg for NLT) with a mean difference of -2.4 ± 7.1 mmHg. Maximal HR was significantly lower in HUTT compared to NLT (92.0 ± 11.4 vs. 96.2 ± 10.8 bpm for NLT) with a mean difference of -4.2 ± 6.9 bpm. Additionally, HR changes were significantly lower in HUTT compared to NLT (21.5 ± 8.1 vs. 27.0 ± 9.0 bpm) with a mean difference of -5.4 ± 6.4 bpm.

Conclusions: The NLT demonstrated comparability with the HUTT in detecting SBP changes. However, clinical applications should consider differences in measuring DBP and HR changes.