Neurohormonal activation in chronic heart failure

Transcription

1 Effects of ACE Gene Insertion/Deletion Polymorphism on Response to in Patients with Chronic Heart Failure Mariantonietta Cicoira, MD, Andrea Rossi, MD, Stefano Bonapace, MD, Luisa Zanolla, MD, Andreas Perrot, MSc, Darrel P. Francis, MRCP, Giorgio Golia, MD, Lorenzo Franceschini, MD, Karl J. Osterziel, MD, Piero Zardini, MD BACKGROUND: Angiotensin-converting enzyme (ACE) is involved in the pathophysiology of chronic heart failure, and its activity is determined in part by a polymorphism of the ACE gene. We hypothesized that the benefits of spironolactone, which inhibits downstream elements of ACE-mediated abnormalities, may depend on ACE genotype. METHODS: We randomly assigned 93 chronic heart failure patients to treatment with spironolactone (n 47) or to a control group (n 46) and followed them for 12 months. Genotype for the insertion/deletion polymorphism of the ACE gene was determined by polymerase chain reaction. An echocardiographic examination was performed at baseline and at the end of the 12 months. RESULTS: The mean ( SD) age of the 93 patients was 62 9 years, and the mean New York Heart Association class was 2 1. The genotype was DD in 26 patients (28%). Forty-seven patients were assigned to spironolactone treatment (mean dose, mg). In the treated group, only patients with a non-dd genotype showed significant improvement in left ventricular ejection fraction (3.0%; 95% confidence interval [CI]: 1.2% to 4.8%; P 0.002), end-systolic volume ( 23 ml; 95% CI: 36 to 11; P ), and end-diastolic volume ( 27 ml; 95% CI: 43 to 12; P 0.001). In the multivariate analysis, the estimated net effect of treatment was 29 ml better (95% CI: 20 to 78 ml) for end-diastolic volume, 20 ml better (95% CI: 18 to 58 ml) for end-systolic volume, but 1.4% worse (95% CI: 3.4% to 6.2%) for left ventricular ejection fraction in patients with non-dd versus DD genotypes. CONCLUSION: The effects of spironolactone treatment on left ventricular systolic function and remodeling may in part depend on ACE genotype. Am J Med. 2004;116: by Excerpta Medica Inc. Neurohormonal activation in chronic heart failure is associated with the progression of the disease (1), and increased levels of hormones are closely associated with poor outcomes in these patients (2). Antagonism of the renin-angiotensin-aldosterone system is therefore one of the main goals in the treatment of heart failure patients, and it can be achieved with angiotensinconverting enzyme (ACE) inhibitors. Nevertheless, reactivation of the renin-angiotensin-aldosterone system during ACE inhibitor treatment occurs frequently (3,4), owing to a genetic basis. In fact, an insertion/deletion polymorphism of the ACE gene has been associated with the failure of aldosterone suppression despite ACEinhibitor administration in patients with chronic heart failure (5). The Randomized ALdactone Evaluation Study From Dipartimento di Scienze Biomediche e Chirurgiche (MC, AR, SB, LZ, GG, LF, PZ), Sezione di Cardiologia, Università degli Studi di Verona, Verona, Italy; Universitaetsklinikum Charite (AP, KJO), Kardiologie am Campus Buch & Campus Virchow-Klinikum, und Max-Delbrueck-Centrum fuer Molekulare Medizin, Berlin, Germany; and St. Mary s Hospital (DPF), London, United Kingdom. Dr. Cicoira is supported by a grant from the Italian Society of Cardiology for Cardiovascular Research. Requests for reprints should be addressed to Mariantonietta Cicoira, MD, Divisione di Cardiologia, Ospedale Civile Maggiore, p.le Stefani, Verona, Italy, or mariantonietta.cicoira@univr.it. Manuscript submitted June 11, 2003, and accepted in revised form November 20, (RALES) showed that the aldosterone antagonist spironolactone, when added to ACE-inhibitor therapy, reduces the risk of death in patients with severe chronic heart failure (6). One of the underlying mechanisms might be the improvement of left ventricular systolic function and volumes (7). Nevertheless, the response after treatment varies among patients, with some showing no clear effect. We hypothesized that the beneficial cardiac effects of spironolactone might vary among chronic heart failure patients with different ACE genotypes. METHODS Study Sample This study is part of a randomized trial of spironolactone in chronic heart failure patients; details of the study protocol are given elsewhere (7). In brief, 106 outpatients with chronic heart failure were randomly assigned to spironolactone treatment (25 to 50 mg/d) or a control group for 12 months. Patients were undergoing chronic ACEinhibitor treatment at the maximum tolerated dose. At baseline and after 12 months, a complete echocardiographic examination was performed in all patients. The present study includes all 93 patients from the original study sample (47 assigned to spironolactone treatment) who completed the 12-month follow-up. The protocol was approved by the Ethics Committee of the Azienda 2004 by Excerpta Medica Inc /04/$ see front matter 657 All rights reserved. doi: /j.amjmed

2 Table 1. Baseline Characteristics of the Study Sample Variable Total Sample (n 93) (n 47) (n 46) Mean SD or Number (%) Age (years) Male sex 81 (87) 39 (83) 42 (91) NYHA class Ischemic etiology 56 (60) 29 (62) 27 (59) Beta-blockers 64 (69) 33 (70) 31 (67) Frusemide dose (mg) Body mass index (kg/m 2 ) Serum creatinine ( mol/l)* Serum sodium (meq/l) Plasma norepinephrine (pg/ml) Plasma renin (mui/l) Plasma aldosterone (nmol/l)* Peak oxygen consumption (ml/min/kg) * Serum creatinine: to convert to mg/dl, divide by 88.4; plasma aldosterone: to convert to ng/dl, divide by NYHA New York Heart Association. Ospedaliera of Verona, and patients provided written informed consent for the genetic analysis. Echocardiography The echocardiographic evaluation was performed by a physician who was blinded to the treatment group. Left ventricular end-diastolic and end-systolic diameters, wall thickness, and left atrial diameter were measured by M- mode echocardiography from the parasternal long-axis view, as recommended by the American Society of Echocardiography (8). Left ventricular end-diastolic and endsystolic volumes and ejection fraction were measured from the apical four-chamber view using the monoplane area-length method. Genetic Analysis Genotyping was performed with the DNA of circulating leukocytes obtained from peripheral whole blood. Polymerase chain reaction was used to establish ACE genotype (9,10). Putative DD genotypes were confirmed using the ACE-2 primer (11), which eliminates the likelihood of mistyping that can occur with a two-primer system. Results were scored by two independent investigators who were unaware of patient identity or treatment group. Statistical Analysis According to previous findings from our center (5), patients were grouped by genotype: DD or non-dd. Intergroup comparisons were made using the Student t test, analysis of variance, or chi-squared test, as appropriate. Comparisons between baseline and follow-up values in patients with the same genotype were made using the Student t test for paired data. The estimated net effect of treatment between DD and non-dd genotypes was determined from an interaction term in the multiple regression analysis. A P value 0.05 was considered statistically significant. Data were analyzed using Statview 5.0 (Abacus Concepts Inc, Cary, North Carolina) and Stata (SAS Institute, College Station, Texas). RESULTS The mean ( SD) age of the 93 patients was years (Table 1). Most were men and had chronic heart failure of ischemic origin. Treatment with beta-blockers was relatively common, and was used in 69% of patients. The mean spironolactone dose in the treated group was mg. The genotype was DD in 26 patients (28%), ID in 51 (55%), and II in 16 (17%). The frequencies of the two alleles were 55% for D and 45% for I. The genotype distribution did not differ significantly between the spironolactone and control groups (DD: 32% vs. 24%; ID: 47% vs. 64%; II: 21% vs. 13%; P 0.27). The mean spironolactone dose was similar in patients with different genotypes (DD: mg; ID: mg; II: mg; P 0.82). Thirteen patients did not complete the study: 4 (31%) had a DD genotype, 6 (46%) had an ID genotype, and 3 (23%) had an II genotype, which was similar to the distribution among patients who completed the study (P 0.81). Baseline echocardiographic characteristics, including left ventricular ejection fraction, were similar in patients with different genotypes (Table 2), except for the interventricular septum, which was thicker in patients with the DD genotype compared with those with a non-dd genotype in the control group (both P 0.05), as well as left ventricular volumes, which were also larger in pa- 658 May 15, 2004 THE AMERICAN JOURNAL OF MEDICINE Volume 116

3 Table 2. Baseline Echocardiographic Characteristics of the Study Sample, by Treatment Group and Genotype* Variable (unit) DD (n 15) ID II (n 32) P Value DD (n 11) ID II (n 35) P Value Mean SD Mean SD Left atrial diameter (mm) End-diastolic diameter (mm) End-systolic diameter (mm) Fractional shortening (%) Posterior wall thickness (mm) Interventricular septum (mm) End-diastolic volume (ml) End-systolic volume (ml) Left ventricular ejection fraction (%) * Intergroup comparisons were made using the Student t test for unpaired data. tients with the DD genotype in the control group (all P 0.05). Changes in Echocardiographic Measurements At the end of 12 months, there was a significant increase in fractional shortening in the spironolactone group among patients with a non-dd genotype, whereas there was no change among those with the DD genotype (Table 3). There was only a trend towards improvement in left ventricular end-systolic diameter in patients with a non-dd genotype who were treated with spironolactone. However, in the spironolactone group, there was a significant improvement in left ventricular ejection fraction in patients with a non-dd genotype (mean change: 3.0% 4.9%; P 0.002); the change after treatment (0.2% 5.0% P 0.85) was not significant in those with the DD genotype (Table 3). Similarly, left ventricular volumes decreased significantly after treatment only in patients with a non-dd genotype (end-diastolic volume: ml, P 0.001; end-systolic volume: ml, P ), but did not change in those with the DD genotype (end-diastolic volume: ml, P 0.46; endsystolic volume: 2 36 ml, P 0.79). In comparison, there were no significant changes in ejection fraction or left ventricular volumes in the control group at the end of the 12-month period among both patients with the DD genotype (ejection fraction: 2.9% 5.8%, P 0.12; end-diastolic volume: ml, P 0.57; end-systolic volume: 1 47 ml, P 0.96) and those with a non-dd genotype (ejection fraction: 1.3% 5.2%, P 0.16; end-diastolic volume: 1 54 ml, P 0.88; end-systolic volume: 1 43 ml, P 0.97) (Table 3). Changes from baseline in ejection fraction and enddiastolic and end-systolic volumes between patients with DD and non-dd genotypes were greater in the control group than in the spironolactone group (Table 3). The interaction term in the multiple regression analysis showed that the estimated net effect of treatment was 29 ml better (95% confidence interval [CI]: 20 to 78 ml; P 0.24) for end-diastolic volume, 20 ml better (95% CI: 18 to 58 ml; P 0.31) for end-systolic volume, but 1.4% worse (95% CI: 3.4% to 6.2%; P 0.3) for ejection fraction in patients with non-dd versus DD genotypes. DISCUSSION We found that the previously known effects of spironolactone on cardiac function are at least in part genetically based. We observed an improvement in left ventricular systolic function and volumes only in patients with the II or ID genotypes of the ACE gene who had undergone 12 months of treatment with spironolactone. These results further support the evidence that a genetic polymorphism might contribute to the effects of a drug treatment on cardiac function in chronic heart failure patients. How might the ACE gene insertion/deletion polymorphism influence the effect of spironolactone on cardiac function and volumes? Interindividual variability in the response to antagonism of the renin-angiotensin aldosterone system may be one explanation (12 14). There is evidence that activation of the renin-angiotensinaldosterone system is genetically determined (15,16). Patients who are homozygous for the DD allele have higher serum and tissue ACE levels and activity, and consequently have greater activation of the renin-angiotensinaldosterone system than do patients with the ID or II genotypes (15). Furthermore, we have recently shown that patients with aldosterone escape despite chronic ACE inhibition are more likely to have the DD genotype than are patients with normal aldosterone levels (5). We have also found that patients with the II genotype have adequate aldosterone suppression with chronic ACE inhibition (5). Other investigators have reported that the May 15, 2004 THE AMERICAN JOURNAL OF MEDICINE Volume

4 Table 3. Changes in Echocardiographic Parameters from Baseline to 12-Month Follow-up, by Treatment Group and Genotype* Variable (unit) Genotype Mean Change from Baseline (95% Confidence Interval) P Value Mean Change from Baseline (95% Confidence Interval) P Value Left atrial diameter (mm) DD 0 ( 1.5 to 1.5) ( 5.2 to 8.8) 0.51 Non-DD 0.3 ( 1.1 to 1.9) ( 1.4 to 2.5) 0.58 Difference 0.3 ( 3.4 to 2.7) ( 3.6 to 6.1) 0.6 End-diastolic diameter (mm) DD 4.0 ( 1.1 to 4.7) ( 0.7 to 10.7) 0.07 Non-DD 0.3 ( 1.9 to 2.6) ( 2.4 to 1.8) 0.75 Difference 3.7 ( 0.9 to 8.3) (0.5 to 10.1) 0.03 End-systolic diameter (mm) DD 3.4 ( 4.2 to 11.0) ( 2.3 to 13.1) 0.12 Non-DD 1.6 ( 5.0 to 1.6) ( 2.6 to 1.3) 0.51 Difference 5.0 ( 2.0 to 12.1) (1.1 to 10.9) 0.01 Posterior wall thickness (mm) DD 0.2 ( 2.5 to 2.1) ( 1.2 to 1.1) 0.07 Non-DD 0.4 ( 1.2 to 0.3) ( 0.4 to 1.2) 0.54 Difference 0.2 ( 1.5 to 2.0) ( 2.1 to 0.5) 0.23 Interventricular septum (mm) DD 1.0 ( 3.3 to 1.3) ( 1.8 to 0.1) 0.05 Non-DD 0.3 ( 0.7 to 1.3) ( 0.6 to 1.1) 0.59 Difference 1.2 ( 3.4 to 0.9) ( 3.1 to 0.6) 0.13 Fractional shortening (%) DD 0.6 ( 5.7 to 6.9) ( 9.0 to 5.0) 0.47 Non-DD 3.7 (1.9 to 6.5) ( 1.7 to 3.0) 0.55 Difference 3.1 ( 8.8 to 2.5) ( 8.2 to 2.8) 0.32 End-diastolic volume (ml) DD 10 ( 41 to 20) ( 54 to 32) 0.57 Non-DD 27 ( 43 to 12) ( 18 to 21) 0.88 Difference 17 ( 12 to 46) ( 54 to 29) 0.55 End-systolic volume (ml) DD 2 ( 25 to 19) ( 35 to 37) 0.96 Non-DD 23 ( 36 to 11) ( 15 to 15) 0.97 Difference 21 ( 2 to 44) ( 32 to 34) 0.95 Left ventricular ejection fraction (%) DD 0.2 ( 2.6 to 3.1) ( 6.8 to 1.1) 0.12 Non-DD 3.0 (1.2 to 4.8) ( 0.5 to 3.0) 0.16 Difference 2.8 ( 6.0 to 0.3) ( 7.9 to 0.4) 0.02 * Comparisons between follow-up and baseline measurements were made using the Student t test for paired data. Comparisons between DD and non-dd genotype were made using the Student t test for unpaired data. extent of exercise-induced left ventricular growth in healthy subjects is strongly influenced by the insertion/ deletion polymorphism of the ACE gene (17), and that the DD genotype in patients with dilated cardiomyopathy is associated with poorer systolic function and greater left ventricular size in comparison with the II or ID genotype (18). These findings are consistent with a role of the paracrine renin-angiotensin-aldosterone system in the control of cardiac growth (19). The tissue expression of angiotensin and aldosterone at the cardiac level, which has been associated with ACE gene polymorphisms (20), is particularly important, since elevated ACE levels in cardiac tissue may eventually lead to increased production of cardiac angiotensin II and aldosterone, which are involved in regulating cardiac remodeling and function (21). These observations suggest that ACE gene polymorphisms are involved in determining the response to aldosterone antagonism in terms of cardiac function. Previous studies of ACE inhibitors found that patients with the DD genotype have a significantly lower response to treatment than patients with the II genotype (22,23). However, the endpoints in these studies were renal function and blood pressure, and no previous studies have analyzed the role of ACE gene polymorphisms on cardiac function and remodeling after aldosterone antagonism in patients with chronic heart failure. Our study has several limitations. First, the sample was small. Second, the treatment-genotype interaction term was not statistically significant. Although for ejection fraction the estimated net effect of treatment was better for patients with the DD genotype, the confidence interval suggests that the response could be up to 3.4 times worse in this group of patients. On the other hand, the estimated net effect of treatment for left ventricular volumes was worse in patients with the DD genotype, thus supporting our hypothesis. Third, the study was not a double-blind, placebo-controlled trial. Nevertheless, the physician performing the echocardiographic examination was blinded to the treatment group and genotype. 660 May 15, 2004 THE AMERICAN JOURNAL OF MEDICINE Volume 116

5 Finally, an improvement in left ventricular function represents only a surrogate endpoint in patients with chronic heart failure, which does not necessarily imply a prognostic benefit. This question might be answered by larger prospective studies specifically designed to assess the effect of aldosterone antagonism on outcome in relation to genotype status. It seems, therefore, that patients with the II genotype not only have a less activated renin-angiotensin-aldosterone system at baseline, but also a better response to endocrine antagonism at different levels of the system. Furthermore, these patients have a lower risk of developing chronic heart failure and ischemic heart disease (24,25). The opposite is true for patients with the DD genotype. Still, patients with the DD genotype probably should not be considered nonresponders to aldosterone antagonism for several reasons. In our study, patients in the control group with the DD genotype showed a trend towards worsening of left ventricular systolic function and left ventricular remodeling, while patients with the same genotype in the spironolactone group remained stable over time. Furthermore, the difference in changes in ejection fraction between DD and non-dd genotype was even larger in the control group than in the spironolactone group. We wish to emphasize that the hypothesized effects of ACE gene polymorphisms on drug efficacy and cardiac function in patients with chronic heart failure should be confirmed in larger randomized studies. REFERENCES 1. Packer M. The neurohormonal hypothesis: a theory to explain the mechanisms of disease progression in heart failure. J Am Coll Cardiol. 1992;20: Swedberg K, Eneroth P, Kjekshus J, et al, for the CONSENSUS Trial Study Group. Hormones regulating cardiovascular function in patients with severe congestive heart failure and their relation to mortality. 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