Journal of Human Hypertension (2014) 28, 606–609 & 2014 Macmillan Publishers Limited All rights reserved 0950-9240/14 www.nature.com/jhh
ORIGINAL ARTICLE
Increased thrombotic and impaired fibrinolytic response to acute exercise in patients with essential hypertension: The effect of treatment with an angiotensin II receptor blocker E Gavriilaki1,4, E Gkaliagkousi2,4, B Nikolaidou2, G Triantafyllou1, F Chatzopoulou3 and S Douma1 Essential hypertension (EH) is characterised by increased thrombotic tendency and impaired fibrinolytic activity. However, exerciseinduced changes in coagulation and fibrinolysis have not yet been clarified. We aimed at determining thrombotic and fibrinolytic activity during exercise in patients with EH pre and post treatment with an Angiotensin II receptor blocker. Study 1 consisted of 30 untreated hypertensive (UH) and 15 normotensive (NT) individuals. The UH individuals who received treatment were included in study 2 and were followed up after a 3-month treatment period with valsartan. Thrombin–antithrombin (TAT) complexes and human plasminogen activator inhibitor-1 (PAI-1) were measured as markers of coagulation and fibrinolysis, respectively, at baseline, immediately after a treadmill exercise test and 30 min later. In UH, TAT and PAI-1 levels were significantly increased immediately after peak exercise and decreased 30 min later, as compared with baseline levels. At all time points, UH exhibited significantly higher TAT and PAI-1 levels compared with NT. No significant changes of TAT and PAI-1 levels were observed in NT and in patients post treatment. Acute high-intensity exercise results in impaired thrombotic and fibrinolytic response in untreated patients with EH. Angiotensin II receptor blockade with adequate blood pressure control greatly improves exercise-induced changes in coagulation and fibrinolysis in EH. Journal of Human Hypertension (2014) 28, 606–609; doi:10.1038/jhh.2014.18; published online 13 March 2014
INTRODUCTION Essential hypertension (EH) represents a major public health problem leading to increased cardiovascular and overall mortality.1 The prothrombotic state in EH is sustained by a number of factors, including hypercoagulability and impaired fibrinolytic activity.2–4 Thrombin–antithrombin III (TAT) complexes have been used as a marker of thrombin generation in several clinical settings, including patients with increased cardiovascular risk.5 On the other hand, plasminogen activator inhibitor-1 (PAI-1) is considered one of the most robust marker of the fibrinolytic activity, as it is the major inhibitor of tissue-type plasminogen activator.6 Furthermore it has been implicated in the pathogenesis of vascular damage and atherothrombotic events.6 Hemostatic imbalance favoring a prothrombotic state has been reported in patients with pre-hypertension7 and never-treated EH2,3 while increased PAI-1 levels have been also associated with the incidence of hypertension.8 In addition, there are only a few studies, with conflicting results, which have investigated the balance between coagulation and fibrinolysis at rest, during, and after, acute exercise in patients with EH.9–12 Thus, the objectives of our study were firstly to estimate the effect of acute high-intensity exercise on the levels of two of the most representative markers of coagulation and fibrinolysis, TAT and PAI-1, in subjects with untreated EH (UH) as compared with normotensive (NT) individuals; and secondly to investigate the effects of treatment with an angiotensin II receptor blocker (ARB).
MATERIALS AND METHODS Study population Study 1. Our study population consisted of consecutive individuals attending our hypertension unit during a 6-month period (January– June 2011). Healthy individuals were recruited from the community during the same period. Sample size was calculated using the standardised formula for case-control studies. The ratio between the two groups was defined at 2:1. Power was defined at 80% for 1% level of significance. Based on initial estimations of TAT and PAI-1 levels in hypertensive and NT individuals, total sample size required was calculated at 40 subjects. All subjects were clinically healthy, with no evidence from medical history and physical examination of cardiovascular disease (other than EH) or other significant co-morbidity. Secondary hypertension was excluded, when indicated, by measuring plasma renin activity, serum aldosterone and urinary catecholamine levels. Participants had never been treated with antihypertensive agents and were not on regular treatment with lipidlowering therapy, aspirin, nonsteroidal anti-inflammatory or other antiplatelet medication. All individuals were sedentary, admitting to little or no regular exercise. Office blood pressure was measured in the dominant arm using a validated oscillometric device (Omron 705IT, Omron Healthcare Europe BV, Hoofddorp, the Netherlands) after 15 min of rest in a quiet temperature-controlled room (23 1C) in the seated position. Ambulatory blood pressure measurement was subsequently performed in the left upper arm using a SpaceLabs 90207 device (Spacelabs Healthcare, Issaquah, WA, USA) according to a standard protocol, which has been previously described.13 According to recently published guidelines,1 subjects with white-coat or masked hypertension were excluded from this study.
1 3rd Department of Internal Medicine, Papageorgiou Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece; 22nd Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece and 3Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece. Correspondence: Dr E Gkaliagkousi, 2nd Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Hippokration Hospital of Thessaloniki, Konstantinoupoleos 49, Thessaloniki 54643, Greece. E-mail: [email protected] 4 These authors contributed equally to this work. Received 21 October 2013; revised 13 January 2014; accepted 16 January 2014; published online 13 March 2014
Exercise-induced changes in coagulation and fibrinolysis E Gavriilaki et al
607 All subjects gave written-informed consent and the procedures followed were in accordance with institutional guidelines. The study was approved by the Hippokrateion Hospital Ethics Committee and was in accordance with the principles of the Helsinki declaration. Study 2. After completion of the study procedures all hypertensive individuals were subsequently referred to the hypertension specialists of our clinic. When antihypertensive therapy was indicated, treatment was initiated with an ARB (valsartan 160 mg). Patients did not receive any other medication. All patients who received antihypertensive treatment were reevaluated at a follow up visit after a 3-month period where the same protocol was repeated.
Laboratory measurements All subjects underwent a treadmill exercise test, according to the Bruce protocol,14 as previously described.13 All tests were performed at 9am after an overnight fast and the subject having abstained from caffeine and smoking for at least 8 h. With the subject in the supine position, an intravenous indwelling cannula (18G) was inserted and isotonic saline (0.9% NaCl) was infused at a rate of 1 ml min 1 during the test. Blood samples were drawn at the following time points: just before the treadmill exercise, peak exercise and 30 min later during the recovery period (referred to as 30R), with the subject in the supine position. These time points were selected on the basis of preliminary experiments, which clarified the time course over which circulating TAT and PAI-1 decreased to pre-exercise test levels. Blood samples were centrifuged and stored at 801C. Commercially available Enzyme-linked Immunosorbent Assay (ELISA) kits (AssayMax Human Thrombin–antithrombin Complexes ELISA Kit, Loxo GMBH, Dossenheim, Germany and AssayMax Human Plasminogen Activator Inhibitor-1 ELISA Kit, Loxo GMBH) were used for the determination of TAT and PAI-1 levels, respectively. Minimum detectable dose of TAT complexes is typically 1.5 ng ml 1 with intra-assay and inter-assay coefficients of variation at 4.9% and 7.2%, respectively. Minimum detectable dose of PAI-1 is typically 0.07 ng ml 1 with intra-assay and inter-assay coefficients of variation at 4.7% and 7.2%, respectively.
Statistical analysis Analysis was performed using the Statistical Package for Social Sciences (SPSS) 20.0 for Windows (SPSS Inc., Chicago, IL, USA). Results are presented for continuous variables as mean±s.d. or (for nonnormal variables) as median (interquartile range), and for qualitative variables as frequencies. Statistical analyses were carried out using the independent samples Student’s t-test or the Mann–Whitney-U test and repeated measures analysis of variance (with Bonferroni’s post-hoc test) or Friedman’s test. Logarithmic transformation was performed when appropriate. A probability value of Po0.05 was considered statistically significant.
RESULTS Overall, 30 patients with UH and 15 age- and sex-matched NT were eligible for, and agreed to participate in the study. No significant differences were observed between the two groups with regard to smoking status, body mass index, lipid profile (total, high- and low-density lipoprotein cholesterol and triglycerides) and glucose levels, as shown in Table 1. All study participants reported an alcohol intake of o5 units per week (1 unit ¼ 12 mgs of alcohol). As expected, UH had significantly higher systolic blood pressure and diastolic blood pressure (both office and ambulatory) compared with NT (Table 1). All study participants achieved target heart rate, with no reasons for premature termination of the exercise test. There was no difference in the maximum metabolic equivalents among the two groups (9.68±1.82 in UH vs 10.2±1.67 in NT; P ¼ 0.328), indicating that all participants had successfully performed highintensity exercise. In UH, TAT and PAI-1 levels were significantly increased immediately after peak exercise (P ¼ 0.030 and P ¼ 0.036, respectively) and decreased 30 min later, as compared with baseline levels (Table 2). On the contrary, no significant changes & 2014 Macmillan Publishers Limited
Table 1.
Subject baseline characteristics
Number (male/female) Age (years) Smoking (%) BMI (kg m 2) Waist circumference (cm) Glucose (mg dl 1) eGFR (ml min 1) Total cholesterol (mg dl 1) LDL cholesterol (mg dl 1) HDL cholesterol (mg dl 1) Triglycerides (mg dl 1) Office SBP (mm Hg) Office DBP (mm Hg) Pulse (min 1) 24-h SBP (mm Hg) 24-h DBP (mm Hg) Day-time SBP (mm Hg) Day-time DBP (mm Hg) Dipping
UH
NT
P-value
30 (23/7) 42.7±6.2 43.3 27.1±3.7 98.1±13.3 90.2±14.8 105.8±20.8 196.0±43.3 126.1±36.5 46.1±9.9 113.5±55.8 147.4±6.8 95.9±6.1 79.2±7.1 138.6±9.4 87.4±7.2 146.1±8.9 95.0±6.7 13.8±6.2
15 (11/4) 42.1±3.7 42.8 25.3±2.6 85.8±6.3 88.9±12.3 112.1±26.3 204.5±41.5 129.0±36.8 48.6±7.7 115.1±47.2 119.4±9.8 75.0±8.2 68.6±4.9 110.6±8.1 73.4±5.7 121.0±7.8 77.7±5.6 10.5±4.2
0.806 0.635 0.914 0.245 0.145 0.649 0.123 0.109 0.237 0.462 0.235 *** *** 0.158 *** *** *** *** 0.546
Abbreviations: BMI, body mass index; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate; HDL, high-density lipoprotein; LDL, low-density lipoprotein; NT, normotensives; SBP, systolic blood pressure; UH, untreated hypertensives. ***Po0.001.
Table 2. TAT and PAI-1 values among different time points in UH, NT and treated hypertensives
1
TATbase (ng ml ) TATmax (ng ml 1) TAT30R (ng ml 1) PAI-1base (ng ml 1) PAI-1max (ng ml 1) PAI-130R (ng ml 1)
UH
NT
Post treatment
136.6±38 152.5±43 132.2±35 4.29±0.62 4.67±0.18 4.45±0.12
110.9±37 129.2±27 117.3±25 4.10±0.48 4.25±0.68 4.18±0.61
114.9±30 130.8±32 109.9±22 4.14±0.39 4.33±0.18 4.08±0.33
Base, pre-exercise values; max, values at maximal exercise; 30R, values 30 min post-exercise.
of PAI-1 levels were reported in the NT group. With regard to TAT levels, NT showed a significant increase immediately after peak exercise and decrease 30 min later. However, UH exhibited significantly higher TAT and PAI-1 levels compared with NT at all time points (P ¼ 0.018, P ¼ 0.022, P ¼ 0.028 and P ¼ 0.030, P ¼ 0.024, P ¼ 0.042, respectively). Results are depicted in Figures 1 and 2. With regard to the follow-up visit, seventeen subjects received antihypertensive treatment with an ARB (valsartan 160 mg) and were followed up after a 3-month period. Subjects who received treatment did not present any significant differences in baseline characteristics as compared with those who did not receive treatment. There were no treatment side effects. All treated subjects achieved adequate blood pressure control (office systolic blood pressure/diastolic blood pressure, 123.7±9.8/ 82.7±11.3 mm Hg; 24-h systolic blood pressure/diastolic blood pressure, 125.7±6.5/78.7±8.2 mm Hg; dipping, 11.3±7.8%). Post-treatment TAT and PAI-1 values were significantly reduced at all time points (P ¼ 0.008, P ¼ 0.019, P ¼ 0.028 and P ¼ 0.017, P ¼ 0.020, P ¼ 0.022, respectively) and were similar to those of the NT group. Results are summarized in Figures 1 and 2 and Table 2. Journal of Human Hypertension (2014) 606 – 609
Exercise-induced changes in coagulation and fibrinolysis E Gavriilaki et al
608
Figure 1. TAT levels in response to high-intensity exercise in UH, NT and patient post treatment. *Po0.05 in UH vs NT or post treatment.
Figure 2. PAI-1 levels in response to high-intensity exercise in UH, NT and patient post treatment. *Po0.05 in UH vs NT or post treatment.
DISCUSSION In the present study we sought to investigate the prothrombotic state observed in EH, by measuring TAT and PAI-1, two traditional and robust markers of hypercoagulability and impaired fibrinolysis, respectively, before and after acute high-intensity exercise. Our findings indicate that high-intensity acute exercise results in increased coagulant and impaired fibrinolytic activity in naive patients with a recent diagnosis of EH. Furthermore, we report for the first time that antihypertensive treatment with an ARB neutralizes these exercise-induced effects resulting in responses similar to those of NT individuals. Studies of coagulation and fibrinolysis changes following acute exercise in patients with EH are limited.9–12 Although the hypercoagulant response to acute exercise is evident in all studies, results on fibrinolytic activity are less clear and largely dependent on the type and degree of exercise. For instance several recent studies have shown beneficial effects of moderate exercise on fibrinolytic activity in EH. Lekakis et al.10 reported a higher and prolonged increase in fibrinolytic activity over coagulant activity in 20 middle-aged never-treated hypertensive subjects of unknown physical status following sub-maximal acute exercise. Similarly, a favorable fibrinolytic response was documented after moderate acute exercise in older hypertensives.11 By contrast, von Ka¨nel et al.9 showed that impaired fibrinolytic activity is associated with lower fitness status in 26 never-treated hypertensives. On the other hand, the effect of exercise intensity on fibrinolysis has been studied only in health and not in disease states. More specifically it has been shown that high-intensity as compared with moderate exercise15 leads to impaired fibrinolytic response in healthy physically active men. Thus, exercise intensity and subjects’ physical status strongly influence the fibrinolytic response. Moreover, while moderate exercise enhances fibrinolysis, the Journal of Human Hypertension (2014) 606 – 609
impact of high-intensity exercise remains understudied both in healthy individuals and in individuals with cardiovascular diseases and specifically those with EH. Our study has investigated for the first time the impact of high-intensity exercise on fibrinolysis in naive patients with EH and has documented an impaired fibrinolytic response. Furthermore, available data about post-treatment changes in exercise-induced activation of coagulation and fibrinolysis are scant. Long-term treatment with an angiotensin-converting enzyme inhibitor resulted in an attenuated activation of coagulation and fibrinolysis following sub-maximal acute exercise.16 In another study, patients treated with ARBs exhibited a less marked increase in coagulant and fibrinolytic activity following highintensity acute exercise than those treated with calcium channel blockers.17 Interestingly, this study showed a favorable effect of high-intensity acute exercise in treated patients with EH indicating a protective role of antihypertensive treatment. In the present study we have shown that high-intensity acute exercise leads to an impaired fibrinolytic response in sedentary never-treated hypertensive individuals, while treatment with an ARB reduces hypercoagulability and enhances fibrinolysis. Our study has several limitations. Firstly, coagulation and fibrinolysis activity was assessed using one representative marker of the activity of each system. Investigating other known markers of coagulation and fibrinolysis in well-designed studies would be useful. Secondly, we studied a small number of relatively young UH patients with a recent diagnosis of EH and no comorbidities. Thus, our findings are relevant only to the first stages of EH and care should be taken in extrapolating these findings to the whole hypertensive population. Finally, the effects of different renin– angiotensin system blockers or antihypertensive agents of different classes on exercise-induced changes in coagulation and fibrinolysis need to be further investigated. In conclusion, changes in coagulation and fibrinolysis following high-intensity acute exercise remain to be a phenomenon that is largely understudied. To our knowledge, this is the first study to document pre- and post-treatment changes of this phenomenon in EH, which together with exaggerated exercise-induced platelet activation13 may explain the deleterious effects of acute highintensity exercise in the cardiovascular system. A 3-month treatment period with an ARB greatly improved exercise-induced changes in coagulation and fibrinolysis in hypertensive patients. Whether this effect depends purely on blood pressure lowering or on the pleiotropic effects of an ARB needs to be investigated. Therefore, further studies are needed in order to confirm the longterm effect of antihypertensive treatment with renin–angiotensin system blockers or agents from different classes.
What is known about the topic? Studies of coagulation and fibrinolysis changes following acute exercise in patients with EH are limited. Although the hypercoagulant response to acute exercise is evident in all studies, results on fibrinolytic activity are less clear and largely dependent on the type and degree of exercise. What this study adds? In the present study we have shown that high-intensity acute exercise leads to an increased coagulant and impaired fibrinolytic response in sedentary never-treated hypertensive individuals. To our knowledge, this is the first study to document the fact that the treatment with an ARB reduces exercise-induced hypercoagulability and enhances fibrinolysis.
CONFLICT OF INTEREST The authors declare no conflict of interest.
& 2014 Macmillan Publishers Limited
Exercise-induced changes in coagulation and fibrinolysis E Gavriilaki et al
609 REFERENCES 1 Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Bohm M et al. 2013 ESH/ ESC Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J 2013; 34: 2159–2219. 2 Trifiletti A, Barbera N, Pizzoleo MA, Lasco A, Lucifora S, Leone G et al. Haemostatic variables in arterial hypertension. Haemostasis 1995; 25(5): 237–240. 3 Makris TK, Tsoukala C, Krespi P, Hatzizacharias A, Gialeraki A, Papargyriou J et al. Haemostasis balance disorders in patients with essential hypertension. Thromb Res 1997; 88(2): 99–107. 4 Yang P, Liu YF, Yang L, Wei Q, Zeng H. Mechanism and clinical significance of the prothrombotic state in patients with essential hypertension. Clin Cardiol 2010; 33(6): E81–E86. 5 Morange PE, Bickel C, Nicaud V, Schnabel R, Rupprecht HJ, Peetz D et al. Haemostatic factors and the risk of cardiovascular death in patients with coronary artery disease: the AtheroGene study. Arterioscler Thromb Vasc Biol 2006; 26(12): 2793–2799. 6 Vaughan DE. PAI-1 and atherothrombosis. J Thromb Haemost 2005; 3(8): 1879–1883. 7 Papadopoulos D, Mourouzis I, Kotrotsou A, Papazachou U, Sanidas E, Tsioufis K et al. Hemostasis parameters disturbances in healthy individuals with prehypertension. Clin Exp Hypertens 2012; 34(6): 385–388. 8 Wang TJ, Gona P, Larson MG, Levy D, Benjamin EJ, Tofler GH et al. Multiple biomarkers and the risk of incident hypertension. Hypertension 2007; 49(3): 432–438. 9 von Kanel R, Hong S, Pung MA, Mills PJ. Association of blood pressure and fitness with levels of atherosclerotic risk markers pre-exercise and post-exercise. Am J Hypertens 2007; 20(6): 670–675.
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10 Lekakis J, Triantafyllidi H, Galea V, Koutroumbi M, Theodoridis T, Komporozos C et al. The immediate effect of aerobic exercise on haemostatic parameters in patients with recently diagnosed mild to moderate essential hypertension. J Thromb Thrombolysis 2008; 25(2): 179–184. 11 DeSouza CA, Dengel DR, Rogers MA, Cox K, Macko RF. Fibrinolytic responses to acute physical activity in older hypertensive men. J Appl Physiol (1985) 1997; 82(6): 1765–1770. 12 Liakos CI, Vyssoulis GP, Michaelides AP, Chatzistamatiou EI, Theodosiades G, Toutouza MG et al. The effects of angiotensin receptor blockers vs calcium channel blockers on the acute exercise-induced inflammatory and thrombotic response. Hypertens Res 2012; 35(12): 1193–1200. 13 Gkaliagkousi E, Gavriilaki E, Yiannaki E, Markala D, Papadopoulos N, Triantafyllou A et al. Platelet activation in essential hypertension during exercise: pre- and posttreatment changes with an angiotensin II receptor blocker. Am J Hypertens (e-pub ahead of print 23 August 2013). 14 Gibbons RJ, Balady GJ, Beasley JW, Bricker JT, Duvernoy WF, Froelicher VF et al. ACC/AHA guidelines for exercise testing: executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Exercise Testing). Circulation 1997; 96(1): 345–354. 15 Szymanski LM, Pate RR. Effects of exercise intensity, duration, and time of day on fibrinolytic activity in physically active men. Med Sci Sports Exerc 1994; 26(9): 1102–1108. 16 Galea V, Triantafyllidi H, Theodoridis T, Koutroumbi M, Christopoulou-Cokkinou V, Kremastinos D et al. Long-term treatment with ramipril favourably modifies the haemostatic response to acute submaximal exercise in hypertensives. J Renin Angiotensin Aldosterone Syst 2012; 14: 322–329. 17 Liakos CI, Michaelides AP, Vyssoulis GP, Chatzistamatiou EI, Dilaveris PE, Markou MI et al. The antihypertensive treatment effect on left ventricular diastolic function is reflected in exercise electrocardiogram. J Electrocardiol 2012; 45(1): 28–35.
Journal of Human Hypertension (2014) 606 – 609
ORIGINAL ARTICLE
Increased thrombotic and impaired fibrinolytic response to acute exercise in patients with essential hypertension: The effect of treatment with an angiotensin II receptor blocker E Gavriilaki1,4, E Gkaliagkousi2,4, B Nikolaidou2, G Triantafyllou1, F Chatzopoulou3 and S Douma1 Essential hypertension (EH) is characterised by increased thrombotic tendency and impaired fibrinolytic activity. However, exerciseinduced changes in coagulation and fibrinolysis have not yet been clarified. We aimed at determining thrombotic and fibrinolytic activity during exercise in patients with EH pre and post treatment with an Angiotensin II receptor blocker. Study 1 consisted of 30 untreated hypertensive (UH) and 15 normotensive (NT) individuals. The UH individuals who received treatment were included in study 2 and were followed up after a 3-month treatment period with valsartan. Thrombin–antithrombin (TAT) complexes and human plasminogen activator inhibitor-1 (PAI-1) were measured as markers of coagulation and fibrinolysis, respectively, at baseline, immediately after a treadmill exercise test and 30 min later. In UH, TAT and PAI-1 levels were significantly increased immediately after peak exercise and decreased 30 min later, as compared with baseline levels. At all time points, UH exhibited significantly higher TAT and PAI-1 levels compared with NT. No significant changes of TAT and PAI-1 levels were observed in NT and in patients post treatment. Acute high-intensity exercise results in impaired thrombotic and fibrinolytic response in untreated patients with EH. Angiotensin II receptor blockade with adequate blood pressure control greatly improves exercise-induced changes in coagulation and fibrinolysis in EH. Journal of Human Hypertension (2014) 28, 606–609; doi:10.1038/jhh.2014.18; published online 13 March 2014
INTRODUCTION Essential hypertension (EH) represents a major public health problem leading to increased cardiovascular and overall mortality.1 The prothrombotic state in EH is sustained by a number of factors, including hypercoagulability and impaired fibrinolytic activity.2–4 Thrombin–antithrombin III (TAT) complexes have been used as a marker of thrombin generation in several clinical settings, including patients with increased cardiovascular risk.5 On the other hand, plasminogen activator inhibitor-1 (PAI-1) is considered one of the most robust marker of the fibrinolytic activity, as it is the major inhibitor of tissue-type plasminogen activator.6 Furthermore it has been implicated in the pathogenesis of vascular damage and atherothrombotic events.6 Hemostatic imbalance favoring a prothrombotic state has been reported in patients with pre-hypertension7 and never-treated EH2,3 while increased PAI-1 levels have been also associated with the incidence of hypertension.8 In addition, there are only a few studies, with conflicting results, which have investigated the balance between coagulation and fibrinolysis at rest, during, and after, acute exercise in patients with EH.9–12 Thus, the objectives of our study were firstly to estimate the effect of acute high-intensity exercise on the levels of two of the most representative markers of coagulation and fibrinolysis, TAT and PAI-1, in subjects with untreated EH (UH) as compared with normotensive (NT) individuals; and secondly to investigate the effects of treatment with an angiotensin II receptor blocker (ARB).
MATERIALS AND METHODS Study population Study 1. Our study population consisted of consecutive individuals attending our hypertension unit during a 6-month period (January– June 2011). Healthy individuals were recruited from the community during the same period. Sample size was calculated using the standardised formula for case-control studies. The ratio between the two groups was defined at 2:1. Power was defined at 80% for 1% level of significance. Based on initial estimations of TAT and PAI-1 levels in hypertensive and NT individuals, total sample size required was calculated at 40 subjects. All subjects were clinically healthy, with no evidence from medical history and physical examination of cardiovascular disease (other than EH) or other significant co-morbidity. Secondary hypertension was excluded, when indicated, by measuring plasma renin activity, serum aldosterone and urinary catecholamine levels. Participants had never been treated with antihypertensive agents and were not on regular treatment with lipidlowering therapy, aspirin, nonsteroidal anti-inflammatory or other antiplatelet medication. All individuals were sedentary, admitting to little or no regular exercise. Office blood pressure was measured in the dominant arm using a validated oscillometric device (Omron 705IT, Omron Healthcare Europe BV, Hoofddorp, the Netherlands) after 15 min of rest in a quiet temperature-controlled room (23 1C) in the seated position. Ambulatory blood pressure measurement was subsequently performed in the left upper arm using a SpaceLabs 90207 device (Spacelabs Healthcare, Issaquah, WA, USA) according to a standard protocol, which has been previously described.13 According to recently published guidelines,1 subjects with white-coat or masked hypertension were excluded from this study.
1 3rd Department of Internal Medicine, Papageorgiou Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece; 22nd Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece and 3Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece. Correspondence: Dr E Gkaliagkousi, 2nd Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Hippokration Hospital of Thessaloniki, Konstantinoupoleos 49, Thessaloniki 54643, Greece. E-mail: [email protected] 4 These authors contributed equally to this work. Received 21 October 2013; revised 13 January 2014; accepted 16 January 2014; published online 13 March 2014
Exercise-induced changes in coagulation and fibrinolysis E Gavriilaki et al
607 All subjects gave written-informed consent and the procedures followed were in accordance with institutional guidelines. The study was approved by the Hippokrateion Hospital Ethics Committee and was in accordance with the principles of the Helsinki declaration. Study 2. After completion of the study procedures all hypertensive individuals were subsequently referred to the hypertension specialists of our clinic. When antihypertensive therapy was indicated, treatment was initiated with an ARB (valsartan 160 mg). Patients did not receive any other medication. All patients who received antihypertensive treatment were reevaluated at a follow up visit after a 3-month period where the same protocol was repeated.
Laboratory measurements All subjects underwent a treadmill exercise test, according to the Bruce protocol,14 as previously described.13 All tests were performed at 9am after an overnight fast and the subject having abstained from caffeine and smoking for at least 8 h. With the subject in the supine position, an intravenous indwelling cannula (18G) was inserted and isotonic saline (0.9% NaCl) was infused at a rate of 1 ml min 1 during the test. Blood samples were drawn at the following time points: just before the treadmill exercise, peak exercise and 30 min later during the recovery period (referred to as 30R), with the subject in the supine position. These time points were selected on the basis of preliminary experiments, which clarified the time course over which circulating TAT and PAI-1 decreased to pre-exercise test levels. Blood samples were centrifuged and stored at 801C. Commercially available Enzyme-linked Immunosorbent Assay (ELISA) kits (AssayMax Human Thrombin–antithrombin Complexes ELISA Kit, Loxo GMBH, Dossenheim, Germany and AssayMax Human Plasminogen Activator Inhibitor-1 ELISA Kit, Loxo GMBH) were used for the determination of TAT and PAI-1 levels, respectively. Minimum detectable dose of TAT complexes is typically 1.5 ng ml 1 with intra-assay and inter-assay coefficients of variation at 4.9% and 7.2%, respectively. Minimum detectable dose of PAI-1 is typically 0.07 ng ml 1 with intra-assay and inter-assay coefficients of variation at 4.7% and 7.2%, respectively.
Statistical analysis Analysis was performed using the Statistical Package for Social Sciences (SPSS) 20.0 for Windows (SPSS Inc., Chicago, IL, USA). Results are presented for continuous variables as mean±s.d. or (for nonnormal variables) as median (interquartile range), and for qualitative variables as frequencies. Statistical analyses were carried out using the independent samples Student’s t-test or the Mann–Whitney-U test and repeated measures analysis of variance (with Bonferroni’s post-hoc test) or Friedman’s test. Logarithmic transformation was performed when appropriate. A probability value of Po0.05 was considered statistically significant.
RESULTS Overall, 30 patients with UH and 15 age- and sex-matched NT were eligible for, and agreed to participate in the study. No significant differences were observed between the two groups with regard to smoking status, body mass index, lipid profile (total, high- and low-density lipoprotein cholesterol and triglycerides) and glucose levels, as shown in Table 1. All study participants reported an alcohol intake of o5 units per week (1 unit ¼ 12 mgs of alcohol). As expected, UH had significantly higher systolic blood pressure and diastolic blood pressure (both office and ambulatory) compared with NT (Table 1). All study participants achieved target heart rate, with no reasons for premature termination of the exercise test. There was no difference in the maximum metabolic equivalents among the two groups (9.68±1.82 in UH vs 10.2±1.67 in NT; P ¼ 0.328), indicating that all participants had successfully performed highintensity exercise. In UH, TAT and PAI-1 levels were significantly increased immediately after peak exercise (P ¼ 0.030 and P ¼ 0.036, respectively) and decreased 30 min later, as compared with baseline levels (Table 2). On the contrary, no significant changes & 2014 Macmillan Publishers Limited
Table 1.
Subject baseline characteristics
Number (male/female) Age (years) Smoking (%) BMI (kg m 2) Waist circumference (cm) Glucose (mg dl 1) eGFR (ml min 1) Total cholesterol (mg dl 1) LDL cholesterol (mg dl 1) HDL cholesterol (mg dl 1) Triglycerides (mg dl 1) Office SBP (mm Hg) Office DBP (mm Hg) Pulse (min 1) 24-h SBP (mm Hg) 24-h DBP (mm Hg) Day-time SBP (mm Hg) Day-time DBP (mm Hg) Dipping
UH
NT
P-value
30 (23/7) 42.7±6.2 43.3 27.1±3.7 98.1±13.3 90.2±14.8 105.8±20.8 196.0±43.3 126.1±36.5 46.1±9.9 113.5±55.8 147.4±6.8 95.9±6.1 79.2±7.1 138.6±9.4 87.4±7.2 146.1±8.9 95.0±6.7 13.8±6.2
15 (11/4) 42.1±3.7 42.8 25.3±2.6 85.8±6.3 88.9±12.3 112.1±26.3 204.5±41.5 129.0±36.8 48.6±7.7 115.1±47.2 119.4±9.8 75.0±8.2 68.6±4.9 110.6±8.1 73.4±5.7 121.0±7.8 77.7±5.6 10.5±4.2
0.806 0.635 0.914 0.245 0.145 0.649 0.123 0.109 0.237 0.462 0.235 *** *** 0.158 *** *** *** *** 0.546
Abbreviations: BMI, body mass index; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate; HDL, high-density lipoprotein; LDL, low-density lipoprotein; NT, normotensives; SBP, systolic blood pressure; UH, untreated hypertensives. ***Po0.001.
Table 2. TAT and PAI-1 values among different time points in UH, NT and treated hypertensives
1
TATbase (ng ml ) TATmax (ng ml 1) TAT30R (ng ml 1) PAI-1base (ng ml 1) PAI-1max (ng ml 1) PAI-130R (ng ml 1)
UH
NT
Post treatment
136.6±38 152.5±43 132.2±35 4.29±0.62 4.67±0.18 4.45±0.12
110.9±37 129.2±27 117.3±25 4.10±0.48 4.25±0.68 4.18±0.61
114.9±30 130.8±32 109.9±22 4.14±0.39 4.33±0.18 4.08±0.33
Base, pre-exercise values; max, values at maximal exercise; 30R, values 30 min post-exercise.
of PAI-1 levels were reported in the NT group. With regard to TAT levels, NT showed a significant increase immediately after peak exercise and decrease 30 min later. However, UH exhibited significantly higher TAT and PAI-1 levels compared with NT at all time points (P ¼ 0.018, P ¼ 0.022, P ¼ 0.028 and P ¼ 0.030, P ¼ 0.024, P ¼ 0.042, respectively). Results are depicted in Figures 1 and 2. With regard to the follow-up visit, seventeen subjects received antihypertensive treatment with an ARB (valsartan 160 mg) and were followed up after a 3-month period. Subjects who received treatment did not present any significant differences in baseline characteristics as compared with those who did not receive treatment. There were no treatment side effects. All treated subjects achieved adequate blood pressure control (office systolic blood pressure/diastolic blood pressure, 123.7±9.8/ 82.7±11.3 mm Hg; 24-h systolic blood pressure/diastolic blood pressure, 125.7±6.5/78.7±8.2 mm Hg; dipping, 11.3±7.8%). Post-treatment TAT and PAI-1 values were significantly reduced at all time points (P ¼ 0.008, P ¼ 0.019, P ¼ 0.028 and P ¼ 0.017, P ¼ 0.020, P ¼ 0.022, respectively) and were similar to those of the NT group. Results are summarized in Figures 1 and 2 and Table 2. Journal of Human Hypertension (2014) 606 – 609
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608
Figure 1. TAT levels in response to high-intensity exercise in UH, NT and patient post treatment. *Po0.05 in UH vs NT or post treatment.
Figure 2. PAI-1 levels in response to high-intensity exercise in UH, NT and patient post treatment. *Po0.05 in UH vs NT or post treatment.
DISCUSSION In the present study we sought to investigate the prothrombotic state observed in EH, by measuring TAT and PAI-1, two traditional and robust markers of hypercoagulability and impaired fibrinolysis, respectively, before and after acute high-intensity exercise. Our findings indicate that high-intensity acute exercise results in increased coagulant and impaired fibrinolytic activity in naive patients with a recent diagnosis of EH. Furthermore, we report for the first time that antihypertensive treatment with an ARB neutralizes these exercise-induced effects resulting in responses similar to those of NT individuals. Studies of coagulation and fibrinolysis changes following acute exercise in patients with EH are limited.9–12 Although the hypercoagulant response to acute exercise is evident in all studies, results on fibrinolytic activity are less clear and largely dependent on the type and degree of exercise. For instance several recent studies have shown beneficial effects of moderate exercise on fibrinolytic activity in EH. Lekakis et al.10 reported a higher and prolonged increase in fibrinolytic activity over coagulant activity in 20 middle-aged never-treated hypertensive subjects of unknown physical status following sub-maximal acute exercise. Similarly, a favorable fibrinolytic response was documented after moderate acute exercise in older hypertensives.11 By contrast, von Ka¨nel et al.9 showed that impaired fibrinolytic activity is associated with lower fitness status in 26 never-treated hypertensives. On the other hand, the effect of exercise intensity on fibrinolysis has been studied only in health and not in disease states. More specifically it has been shown that high-intensity as compared with moderate exercise15 leads to impaired fibrinolytic response in healthy physically active men. Thus, exercise intensity and subjects’ physical status strongly influence the fibrinolytic response. Moreover, while moderate exercise enhances fibrinolysis, the Journal of Human Hypertension (2014) 606 – 609
impact of high-intensity exercise remains understudied both in healthy individuals and in individuals with cardiovascular diseases and specifically those with EH. Our study has investigated for the first time the impact of high-intensity exercise on fibrinolysis in naive patients with EH and has documented an impaired fibrinolytic response. Furthermore, available data about post-treatment changes in exercise-induced activation of coagulation and fibrinolysis are scant. Long-term treatment with an angiotensin-converting enzyme inhibitor resulted in an attenuated activation of coagulation and fibrinolysis following sub-maximal acute exercise.16 In another study, patients treated with ARBs exhibited a less marked increase in coagulant and fibrinolytic activity following highintensity acute exercise than those treated with calcium channel blockers.17 Interestingly, this study showed a favorable effect of high-intensity acute exercise in treated patients with EH indicating a protective role of antihypertensive treatment. In the present study we have shown that high-intensity acute exercise leads to an impaired fibrinolytic response in sedentary never-treated hypertensive individuals, while treatment with an ARB reduces hypercoagulability and enhances fibrinolysis. Our study has several limitations. Firstly, coagulation and fibrinolysis activity was assessed using one representative marker of the activity of each system. Investigating other known markers of coagulation and fibrinolysis in well-designed studies would be useful. Secondly, we studied a small number of relatively young UH patients with a recent diagnosis of EH and no comorbidities. Thus, our findings are relevant only to the first stages of EH and care should be taken in extrapolating these findings to the whole hypertensive population. Finally, the effects of different renin– angiotensin system blockers or antihypertensive agents of different classes on exercise-induced changes in coagulation and fibrinolysis need to be further investigated. In conclusion, changes in coagulation and fibrinolysis following high-intensity acute exercise remain to be a phenomenon that is largely understudied. To our knowledge, this is the first study to document pre- and post-treatment changes of this phenomenon in EH, which together with exaggerated exercise-induced platelet activation13 may explain the deleterious effects of acute highintensity exercise in the cardiovascular system. A 3-month treatment period with an ARB greatly improved exercise-induced changes in coagulation and fibrinolysis in hypertensive patients. Whether this effect depends purely on blood pressure lowering or on the pleiotropic effects of an ARB needs to be investigated. Therefore, further studies are needed in order to confirm the longterm effect of antihypertensive treatment with renin–angiotensin system blockers or agents from different classes.
What is known about the topic? Studies of coagulation and fibrinolysis changes following acute exercise in patients with EH are limited. Although the hypercoagulant response to acute exercise is evident in all studies, results on fibrinolytic activity are less clear and largely dependent on the type and degree of exercise. What this study adds? In the present study we have shown that high-intensity acute exercise leads to an increased coagulant and impaired fibrinolytic response in sedentary never-treated hypertensive individuals. To our knowledge, this is the first study to document the fact that the treatment with an ARB reduces exercise-induced hypercoagulability and enhances fibrinolysis.
CONFLICT OF INTEREST The authors declare no conflict of interest.
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