TREADMILL EXERCISE TEST INDICATES HYPERTENSION PREVALENCE IN THREE-YEAR FOLLOW-UP STUDY OF INDIVIDUALS WITH HIGH NORMAL BLOOD PRESSURE
Authors: Kalos Theodoros , Dimitriadis Kyriakos , Kakouri Niki , Eirini Siafi , Dimitrios Konstantinidis , Fragkoulis Christos , Tsioufis Panagiotis Anast , Drogkaris Sotirios , Manta Eleni , Mantzouranis Emmanouil , Kariori Maria , Liatakis Ioannis , Tatakis Fotios , Andrikou Ioannis , Kouremeti Maria , Papakonstantinou Panteleimon , Polyzos Dimitrios , Leontsinis Ioannis , Thomopoulos Costas , Tsioufis Konstantinos 
Published: June 2023

Objective:
Assess the relation of blood pressure response to treadmill exercise test in subjects with high normal blood pressure (BP) while sympathetic overactivity assessed by muscle sympathetic nerve activity (MSNA) and arterial stiffening are linked with development of hypertension (HTN).

Design and method:
100 individuals with high normal BP according ESH guidelines, underwent a negative for ischemia treadmill exercise test (Bruce protocol). Arterial stiffness was evaluated based on carotid-femoral pulse wave velocity (PWV). Sympathetic drive was assessed by MSNA. A new index the SBP/MET-slope [(peakSBP—restingSBP)/(peakMET-1)] was used. Follow-up was scheduled every 6 months for 3 consecutive years, where BP measurements were assessed in office and with ambulatory BP monitoring (ABPM). All participants offered lifestyle advise to lower their BP. Endpoint was development of HTN. Then they divided into Group I who developed HTN and Group II without HTN.

Results:
From 100 subjects (54±8 years, 42 males, baseline office BP: 132/82mmHg, 24-hour BP: 122/76mmHg) 40 developed HTN (Group I) and 50 developed HRE (BP >210mmHg in men and >190mmHg in women). Group I vs II had higher HRE (75%vs13%,p = 0.026) with intermediate stage intervals of 3min (159vs146mmHg, p = 0.0001) and 6min (181vs160mmHg,p = 0.0001). The SBP/MET-slope in Group I was increased in all stages till peak exercise independently of sex type (stage1: 7.8vs4.9,p = 0.049, stage2: 6.5vs4.8,p = 0.001, peak: 6.9vs4.4,p = <0.0001). Their exercise capacity was reduced (10vs11.3METs,p = 0.002) as their maximum exercise heart rate (156vs164,p = <0.0001). They demonstrated higher levels of PWV (8.2vs7.2m/sec,p = <0.0001) and MSNA levels (35vs28 bursts,p = <0.0001) both correlated with development of hypertension (p = 0.002), while did not differ regarding their metabolic profile at the follow-up. Echocardiographicly LVMI (80vs74 gr/m2,p = 0.023), left atrium diameter (3.7vs3.5mm,p = 0.018) and isovolumic relaxation time (114vs89ms,p = 0.004) were statistically significant. At their initial ECG had shorter P-wave duration (101vs94,p = 0.022). In ABPM they demonstrated higher night systolic BP (116vs111mmHg,p<0.001). Interestingly, the 2021 CKD-EPI GFR demonstrated a decrease in renal function (91vs97, p = 0.044).

Conclusions:
In subjects with high normal BP, MSNA identifies a state of increased sympathetic overdrive, PWV demonstrates arterial stiffening and exercise testing provides a prognostic value as a hypertension screening tool acknowledging a state of increased systemic vascular resistance progressing to development of hypertension.