Endocrine and haemodynamic changes in resistant hypertension, and blood pressure responses to spironolactone or amiloride

the PATHWAY-2 mechanisms substudies

, Bryan Williams, Thomas M. MacDonald, Steve V. Morant, David J. Webb, Peter Sever, Gordon T. McInnes, Ian Ford, J. Kennedy Cruickshank, Mark J. Caulfield, Sandosh Padmanabhan, Isla S. Mackenzie, Jackie Salsbury, Morris J. Brown (Lead / Corresponding author)

Research output: Contribution to journalArticle

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Abstract

Background: In the PATHWAY-2 study of resistant hypertension, spironolactone reduced blood pressure substantially more than conventional antihypertensive drugs. We did three substudies to assess the mechanisms underlying this superiority and the pathogenesis of resistant hypertension.

Methods: PATHWAY-2 was a randomised, double-blind crossover trial done at 14 UK primary and secondary care sites in 314 patients with resistant hypertension. Patients were given 12 weeks of once daily treatment with each of placebo, spironolactone 25–50 mg, bisoprolol 5–10 mg, and doxazosin 4–8 mg and the change in home systolic blood pressure was assessed as the primary outcome. In our three substudies, we assessed plasma aldosterone, renin, and aldosterone-to-renin ratio (ARR) as predictors of home systolic blood pressure, and estimated prevalence of primary aldosteronism (substudy 1); assessed the effects of each drug in terms of thoracic fluid index, cardiac index, stroke index, and systemic vascular resistance at seven sites with haemodynamic monitoring facilities (substudy 2); and assessed the effect of amiloride 10–20 mg once daily on clinic systolic blood pressure during an optional 6–12 week open-label runout phase (substudy 3). The PATHWAY-2 trial is registered with EudraCT, number 2008–007149–30, and ClinicalTrials.gov, number NCT02369081.

Findings: Of the 314 patients in PATHWAY-2, 269 participated in one or more of the three substudies: 126 in substudy 1, 226 in substudy 2, and 146 in substudy 3. Home systolic blood pressure reduction by spironolactone was predicted by ARR (r2=0·13, p<0·0001) and plasma renin (r2=0·11, p=0·00024). 42 patients had low renin concentrations (predefined as the lowest tertile of plasma renin), of which 31 had a plasma aldosterone concentration greater than the mean value for all 126 patients (250 pmol/L). Thus, 31 (25% [95% CI 17–33]) of 126 patients were deemed to have inappropriately high aldosterone concentrations. Thoracic fluid content was reduced by 6·8% from baseline (95% CI 4·0 to 8·8; p<0·0001) with spironolactone, but not other treatments. Amiloride (10 mg once daily) reduced clinic systolic blood pressure by 20·4 mm Hg (95% CI 18·3–22·5), compared with a reduction of 18·3 mm Hg (16·2–20·5) with spironolactone (25 mg once daily). No serious adverse events were recorded, and adverse symptoms were not systematically recorded after the end of the double-blind treatment. Mean plasma potassium concentrations increased from 4·02 mmol/L (95% CI 3·95–4·08) on placebo to 4·50 (4·44–4·57) on amiloride (p<0·0001).

Interpretation: Our results suggest that resistant hypertension is commonly a salt-retaining state, most likely due to inappropriate aldosterone secretion. Mineralocorticoid receptor blockade by spironolactone overcomes the salt retention and resistance of hypertension to treatment. Amiloride seems to be as effective an antihypertensive as spironolactone, offering a substitute treatment for resistant hypertension.

Original languageEnglish
Pages (from-to)464-475
Number of pages12
JournalThe Lancet Diabetes and Endocrinology
Volume6
Issue number6
Early online date11 Apr 2018
DOIs
Publication statusPublished - 1 Jun 2018

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Spironolactone
Amiloride
Hemodynamics
Blood Pressure
Hypertension
Aldosterone
Renin
Antihypertensive Agents
Thorax
Salts
Placebos
Bisoprolol
Doxazosin
Therapeutics
Mineralocorticoid Receptors
Secondary Care
Hyperaldosteronism
Vascular Resistance
Cross-Over Studies
Primary Health Care

Cite this

Williams, Bryan ; MacDonald, Thomas M. ; Morant, Steve V. ; Webb, David J. ; Sever, Peter ; McInnes, Gordon T. ; Ford, Ian ; Cruickshank, J. Kennedy ; Caulfield, Mark J. ; Padmanabhan, Sandosh ; Mackenzie, Isla S. ; Salsbury, Jackie ; Brown, Morris J. / Endocrine and haemodynamic changes in resistant hypertension, and blood pressure responses to spironolactone or amiloride : the PATHWAY-2 mechanisms substudies. In: The Lancet Diabetes and Endocrinology. 2018 ; Vol. 6, No. 6. pp. 464-475.
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abstract = "Background: In the PATHWAY-2 study of resistant hypertension, spironolactone reduced blood pressure substantially more than conventional antihypertensive drugs. We did three substudies to assess the mechanisms underlying this superiority and the pathogenesis of resistant hypertension.Methods: PATHWAY-2 was a randomised, double-blind crossover trial done at 14 UK primary and secondary care sites in 314 patients with resistant hypertension. Patients were given 12 weeks of once daily treatment with each of placebo, spironolactone 25–50 mg, bisoprolol 5–10 mg, and doxazosin 4–8 mg and the change in home systolic blood pressure was assessed as the primary outcome. In our three substudies, we assessed plasma aldosterone, renin, and aldosterone-to-renin ratio (ARR) as predictors of home systolic blood pressure, and estimated prevalence of primary aldosteronism (substudy 1); assessed the effects of each drug in terms of thoracic fluid index, cardiac index, stroke index, and systemic vascular resistance at seven sites with haemodynamic monitoring facilities (substudy 2); and assessed the effect of amiloride 10–20 mg once daily on clinic systolic blood pressure during an optional 6–12 week open-label runout phase (substudy 3). The PATHWAY-2 trial is registered with EudraCT, number 2008–007149–30, and ClinicalTrials.gov, number NCT02369081.Findings: Of the 314 patients in PATHWAY-2, 269 participated in one or more of the three substudies: 126 in substudy 1, 226 in substudy 2, and 146 in substudy 3. Home systolic blood pressure reduction by spironolactone was predicted by ARR (r2=0·13, p<0·0001) and plasma renin (r2=0·11, p=0·00024). 42 patients had low renin concentrations (predefined as the lowest tertile of plasma renin), of which 31 had a plasma aldosterone concentration greater than the mean value for all 126 patients (250 pmol/L). Thus, 31 (25{\%} [95{\%} CI 17–33]) of 126 patients were deemed to have inappropriately high aldosterone concentrations. Thoracic fluid content was reduced by 6·8{\%} from baseline (95{\%} CI 4·0 to 8·8; p<0·0001) with spironolactone, but not other treatments. Amiloride (10 mg once daily) reduced clinic systolic blood pressure by 20·4 mm Hg (95{\%} CI 18·3–22·5), compared with a reduction of 18·3 mm Hg (16·2–20·5) with spironolactone (25 mg once daily). No serious adverse events were recorded, and adverse symptoms were not systematically recorded after the end of the double-blind treatment. Mean plasma potassium concentrations increased from 4·02 mmol/L (95{\%} CI 3·95–4·08) on placebo to 4·50 (4·44–4·57) on amiloride (p<0·0001).Interpretation: Our results suggest that resistant hypertension is commonly a salt-retaining state, most likely due to inappropriate aldosterone secretion. Mineralocorticoid receptor blockade by spironolactone overcomes the salt retention and resistance of hypertension to treatment. Amiloride seems to be as effective an antihypertensive as spironolactone, offering a substitute treatment for resistant hypertension.",
author = "Bryan Williams and MacDonald, {Thomas M.} and Morant, {Steve V.} and Webb, {David J.} and Peter Sever and McInnes, {Gordon T.} and Ian Ford and Cruickshank, {J. Kennedy} and Caulfield, {Mark J.} and Sandosh Padmanabhan and Mackenzie, {Isla S.} and Jackie Salsbury and Brown, {Morris J.}",
note = "Funding: British Heart Foundation and UK National Institute for Health Research.",
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doi = "10.1016/S2213-8587(18)30071-8",
language = "English",
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journal = "The Lancet: Diabetes and Endocrinology",
issn = "2213-8587",
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Endocrine and haemodynamic changes in resistant hypertension, and blood pressure responses to spironolactone or amiloride : the PATHWAY-2 mechanisms substudies. /; Williams, Bryan; MacDonald, Thomas M.; Morant, Steve V.; Webb, David J.; Sever, Peter; McInnes, Gordon T.; Ford, Ian; Cruickshank, J. Kennedy; Caulfield, Mark J.; Padmanabhan, Sandosh; Mackenzie, Isla S.; Salsbury, Jackie; Brown, Morris J. (Lead / Corresponding author).

In: The Lancet Diabetes and Endocrinology, Vol. 6, No. 6, 01.06.2018, p. 464-475.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Endocrine and haemodynamic changes in resistant hypertension, and blood pressure responses to spironolactone or amiloride

T2 - the PATHWAY-2 mechanisms substudies

AU - Williams, Bryan

AU - MacDonald, Thomas M.

AU - Morant, Steve V.

AU - Webb, David J.

AU - Sever, Peter

AU - McInnes, Gordon T.

AU - Ford, Ian

AU - Cruickshank, J. Kennedy

AU - Caulfield, Mark J.

AU - Padmanabhan, Sandosh

AU - Mackenzie, Isla S.

AU - Salsbury, Jackie

AU - Brown, Morris J.

N1 - Funding: British Heart Foundation and UK National Institute for Health Research.

PY - 2018/6/1

Y1 - 2018/6/1

N2 - Background: In the PATHWAY-2 study of resistant hypertension, spironolactone reduced blood pressure substantially more than conventional antihypertensive drugs. We did three substudies to assess the mechanisms underlying this superiority and the pathogenesis of resistant hypertension.Methods: PATHWAY-2 was a randomised, double-blind crossover trial done at 14 UK primary and secondary care sites in 314 patients with resistant hypertension. Patients were given 12 weeks of once daily treatment with each of placebo, spironolactone 25–50 mg, bisoprolol 5–10 mg, and doxazosin 4–8 mg and the change in home systolic blood pressure was assessed as the primary outcome. In our three substudies, we assessed plasma aldosterone, renin, and aldosterone-to-renin ratio (ARR) as predictors of home systolic blood pressure, and estimated prevalence of primary aldosteronism (substudy 1); assessed the effects of each drug in terms of thoracic fluid index, cardiac index, stroke index, and systemic vascular resistance at seven sites with haemodynamic monitoring facilities (substudy 2); and assessed the effect of amiloride 10–20 mg once daily on clinic systolic blood pressure during an optional 6–12 week open-label runout phase (substudy 3). The PATHWAY-2 trial is registered with EudraCT, number 2008–007149–30, and ClinicalTrials.gov, number NCT02369081.Findings: Of the 314 patients in PATHWAY-2, 269 participated in one or more of the three substudies: 126 in substudy 1, 226 in substudy 2, and 146 in substudy 3. Home systolic blood pressure reduction by spironolactone was predicted by ARR (r2=0·13, p<0·0001) and plasma renin (r2=0·11, p=0·00024). 42 patients had low renin concentrations (predefined as the lowest tertile of plasma renin), of which 31 had a plasma aldosterone concentration greater than the mean value for all 126 patients (250 pmol/L). Thus, 31 (25% [95% CI 17–33]) of 126 patients were deemed to have inappropriately high aldosterone concentrations. Thoracic fluid content was reduced by 6·8% from baseline (95% CI 4·0 to 8·8; p<0·0001) with spironolactone, but not other treatments. Amiloride (10 mg once daily) reduced clinic systolic blood pressure by 20·4 mm Hg (95% CI 18·3–22·5), compared with a reduction of 18·3 mm Hg (16·2–20·5) with spironolactone (25 mg once daily). No serious adverse events were recorded, and adverse symptoms were not systematically recorded after the end of the double-blind treatment. Mean plasma potassium concentrations increased from 4·02 mmol/L (95% CI 3·95–4·08) on placebo to 4·50 (4·44–4·57) on amiloride (p<0·0001).Interpretation: Our results suggest that resistant hypertension is commonly a salt-retaining state, most likely due to inappropriate aldosterone secretion. Mineralocorticoid receptor blockade by spironolactone overcomes the salt retention and resistance of hypertension to treatment. Amiloride seems to be as effective an antihypertensive as spironolactone, offering a substitute treatment for resistant hypertension.

AB - Background: In the PATHWAY-2 study of resistant hypertension, spironolactone reduced blood pressure substantially more than conventional antihypertensive drugs. We did three substudies to assess the mechanisms underlying this superiority and the pathogenesis of resistant hypertension.Methods: PATHWAY-2 was a randomised, double-blind crossover trial done at 14 UK primary and secondary care sites in 314 patients with resistant hypertension. Patients were given 12 weeks of once daily treatment with each of placebo, spironolactone 25–50 mg, bisoprolol 5–10 mg, and doxazosin 4–8 mg and the change in home systolic blood pressure was assessed as the primary outcome. In our three substudies, we assessed plasma aldosterone, renin, and aldosterone-to-renin ratio (ARR) as predictors of home systolic blood pressure, and estimated prevalence of primary aldosteronism (substudy 1); assessed the effects of each drug in terms of thoracic fluid index, cardiac index, stroke index, and systemic vascular resistance at seven sites with haemodynamic monitoring facilities (substudy 2); and assessed the effect of amiloride 10–20 mg once daily on clinic systolic blood pressure during an optional 6–12 week open-label runout phase (substudy 3). The PATHWAY-2 trial is registered with EudraCT, number 2008–007149–30, and ClinicalTrials.gov, number NCT02369081.Findings: Of the 314 patients in PATHWAY-2, 269 participated in one or more of the three substudies: 126 in substudy 1, 226 in substudy 2, and 146 in substudy 3. Home systolic blood pressure reduction by spironolactone was predicted by ARR (r2=0·13, p<0·0001) and plasma renin (r2=0·11, p=0·00024). 42 patients had low renin concentrations (predefined as the lowest tertile of plasma renin), of which 31 had a plasma aldosterone concentration greater than the mean value for all 126 patients (250 pmol/L). Thus, 31 (25% [95% CI 17–33]) of 126 patients were deemed to have inappropriately high aldosterone concentrations. Thoracic fluid content was reduced by 6·8% from baseline (95% CI 4·0 to 8·8; p<0·0001) with spironolactone, but not other treatments. Amiloride (10 mg once daily) reduced clinic systolic blood pressure by 20·4 mm Hg (95% CI 18·3–22·5), compared with a reduction of 18·3 mm Hg (16·2–20·5) with spironolactone (25 mg once daily). No serious adverse events were recorded, and adverse symptoms were not systematically recorded after the end of the double-blind treatment. Mean plasma potassium concentrations increased from 4·02 mmol/L (95% CI 3·95–4·08) on placebo to 4·50 (4·44–4·57) on amiloride (p<0·0001).Interpretation: Our results suggest that resistant hypertension is commonly a salt-retaining state, most likely due to inappropriate aldosterone secretion. Mineralocorticoid receptor blockade by spironolactone overcomes the salt retention and resistance of hypertension to treatment. Amiloride seems to be as effective an antihypertensive as spironolactone, offering a substitute treatment for resistant hypertension.

U2 - 10.1016/S2213-8587(18)30071-8

DO - 10.1016/S2213-8587(18)30071-8

M3 - Article

VL - 6

SP - 464

EP - 475

JO - The Lancet: Diabetes and Endocrinology

JF - The Lancet: Diabetes and Endocrinology

SN - 2213-8587

IS - 6

ER -