Eur J Cardiothorac Surg 2007;31:922-928. doi:10.1016/j.ejcts.2007.01.038
Copyright © 2007, European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved
Changes in B-type natriuretic peptides after surgical ventricular restoration
Ulrik Sartipya,d,*,
Anders Albågea,d,
Per Thomas Larssonc,
Per Insulanderb,
Dan Lindbloma,d
a Department of Cardiothoracic Surgery and Anesthesiology, Karolinska University Hospital, Stockholm, Sweden
b Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
c Department of Clinical Physiology, Karolinska Institutet at Södersjukhuset, Stockholm, Sweden
d Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
Received 17 November 2006;
received in revised form 21 January 2007;
accepted 23 January 2007.
* Corresponding author at: Department of Cardiothoracic Surgery and Anesthesiology, Karolinska University Hospital, SE-171 76 Stockholm, Sweden. Tel.: +46 8 517 728 94; fax: +46 8 33 19 31. (Email: Ulrik.Sartipy{at}karolinska.se).
 |
Abstract
|
|---|
Objective: The aim of this study was to prospectively investigate changes in brain natriuretic peptide (BNP) and amino terminal pro-BNP (NT-pro-BNP) in relation to functional status after surgical ventricular restoration (SVR). Methods: Between March 2003 and May 2006, 29 patients (20 men and 9 women, mean age 65 years, mean ejection fraction 24%) with post-infarction left ventricular aneurysm and depressed left ventricular function underwent SVR according to the Dor technique at our institution. Twenty-two patients (76%) were in New York heart association (NYHA) functional class III or IV. Multi-vessel disease was present in 26 patients. Natriuretic peptides, functional status, ejection fraction and left ventricular volumes were analyzed at baseline, after 6 months, and late postoperatively. Results: There was no early mortality. Survival at 24 months was 93%. Six months postoperatively 25/29 (86%) patients were in NYHA class I and II (p
< 0.001) and at late (mean 21 months) follow-up, all patients were in NYHA class I and II. There was a persistent reduction of NT-pro-BNP (2406 pg/ml vs 1510 pg/ml; p
= 0.03 and 975 pg/ml; p
= 0.03) and BNP (312 pg/ml vs 228 pg/ml; p
= 0.12 and 191 pg/ml; p
= 0.20) 6 months postoperatively and at late follow-up, respectively. Ejection fraction improved from 24% to 37% (p
< 0.001) at 6 months. End-diastolic (110 ml/m2 vs 90 ml/m2, p
= 0.009) and end-systolic (75 ml/m2 vs 52 ml/m2, p
= 0.006) volume index were reduced at 6 months. Functional improvement correlated significantly with reduction in BNP (r
= 0.61, p
= 0.01) and NT-pro-BNP (r
= 0.58, p
= 0.003) 6 months after surgery. Ejection fraction correlated inversely with BNP (r
= –0.58, p
= 0.02) and NT-pro-BNP (r
= –0.51, p
= 0.04), and end-systolic volume correlated with BNP (r
= 0.65, p
= 0.03) and NT-pro-BNP (r
= 0.62, p
= 0.03) 6 months after surgery. Conclusions: Heart failure secondary to post-infarction left ventricular remodeling can be reversed by SVR. Improvement in these patients was associated with reduced levels of B-type natriuretic peptides 6 months after surgery. Clinical improvement was maintained and peptide levels were further reduced at late follow-up.
Key Words: Left ventricular reconstruction • Surgical ventricular restoration • Ventricular remodeling • Natriuretic peptides • Ischemic heart disease • Congestive heart failure
|
1. Introduction
|
|---|
Biomarkers of cardiac function may prove useful in evaluating outcome after heart failure surgery. The geometric adaptation to injury after acute myocardial infarction is known as left ventricular (LV) remodeling and is characterized by gradual increases in LV end-diastolic and end-systolic volumes, wall thinning, increased LV sphericity and progressive worsening of cardiac function resulting in congestive heart failure, and is an important predictor of mortality [1,2]. Surgical ventricular restoration (SVR) by the Dor procedure is a surgical option designed to restore LV shape and volume in patients with ischemic heart disease and heart failure [3,4]. SVR includes complete revascularization, LV reconstruction to restore near-normal shape and volume and, when necessary, mitral valve repair and surgery for ventricular tachycardia [5]. The brain natriuretic peptide (BNP) and amino terminal pro-brain natriuretic peptide (NT-pro-BNP) have been recognized as valuable biomarkers of cardiac function and prognosis in clinical practice [6,7]. Moreover, changes in these neurohormones over time are associated with corresponding changes in subsequent mortality and morbidity in patients with moderate to severe heart failure [8].
We hypothesized that clinical improvement and reduced symptoms of heart failure after SVR would be associated with decreasing levels of B-type natriuretic peptides.
The aim of this study was to prospectively investigate changes in BNP and NT-pro-BNP levels in relation to functional status after SVR. The association between LV ejection fraction, LV volumes and peptide levels were also analyzed.
|
2. Patients and methods
|
|---|
This study was approved by the regional Human Research Ethics Committee, Stockholm, Sweden. Informed consent was obtained from all patients.
2.1 Patient selection
Between March 2003 and May 2006, 29 patients with post-infarction dyskinetic LV aneurysm or large non-aneurysmal akinetic LV were included. Assessment of LV volume and geometry was made by ventriculography and also, in 18 patients operated on since November 2003, by magnetic resonance imaging (MRI). Patients were considered suitable for SVR if they demonstrated an enlarged either dyskinetic or akinetic LV accompanied by LV dysfunction after myocardial infarction and had symptoms of angina and/or heart failure. Patients who had previously undergone cardiac surgery or who had non-anterior dyskinesia/akinesia were excluded.
2.2 Patient characteristics
There were 20 men and 9 women, with a mean age of 65 (44–80) years. Twenty-two patients (76%) were in New York heart association (NYHA) functional class III or IV. Multi-vessel disease was present in 26 patients. The mean preoperative LV ejection fraction was 24% (7–51). Baseline characteristics and indications for surgery are presented in Table 1
. All patients were operated electively. Twenty-four patients underwent preoperative programmed electrical stimulation and 18 patients had inducible VT preoperatively [5]. Three patients had preoperative episodes of spontaneous VT.
View this table:
[in this window]
[in a new window]
|
Table 1 Preoperative patient characteristics and indications for surgery (mean (standard deviation), range) or number of patients)
|
|
2.3 Surgical technique
Surgical ventricular restoration was performed according to the Dor technique, as previously described [5,9]. Mitral valve repair was performed in four patients. In three patients the Alfieri edge-to-edge technique [10] was associated with a posterior annuloplasty without a ring as described by Menicanti et al. [11]. Mitral repair was accomplished in one patient with a rigid ring annuloplasty. In 13 cases a sizing device (TRISVRTM, Chase Medical, Richardson, TX) was used to optimize size and shape of the new ventricle.
2.4 Outcome measures
2.4.1 Measurement of levels of BNP and NT-pro-BNP
Preoperative blood samples were collected in all 29 patients. Postoperative samples were collected in 24 patients at 6 months after surgery. At late follow-up, 20 patients had more than 12 months follow-up, and samples were acquired from all 20 patients. In the first ten patients, arterial blood samples were collected into chilled tubes, immediately centrifuged at 4 °C to separate the plasma. The plasma samples were preserved at –70 °C for later analysis. By this procedure, samples were obtained preoperatively and 6 months postoperatively. In the remaining patients, and in all patients at late follow-up, venous blood samples were collected for same day analysis. Measurements of peptide levels were performed by the Department of Clinical Chemistry at the Karolinska University Hospital using commercially available kits (BNP: SHIONORIA BNP, CIS Bio International, France and NT-pro-BNP: Elecsys, Roche Diagnostics).
2.4.2 New York heart association functional class
The NYHA functional class was assessed 1 and 2 weeks before surgery, 6 months postoperatively, and at late follow-up.
2.4.3 Left ventricular ejection fraction
Ejection fraction was assessed by radionuclide ventriculography and/or echocardiography 1–2 weeks before surgery and repeated 6 months postoperatively.
2.4.4 Cardiac magnetic resonance imaging
Cardiac MRI (1.5-T Symphony, Siemens, Erlangen, Germany) was performed 1–4 weeks before surgery and repeated 6 months postoperatively.
2.4.5 Survival
The date for death was established by use of a continuously updated national population register; the Total Population Register, Statistics Sweden.
2.5 Statistical analyses
Data are presented as mean and standard deviation, median or number of patients. Pre- and postoperative intra-group comparisons were performed with non-parametric tests for dependent samples; the Wilcoxon signed ranks test or the marginal homogeneity test, which is an extension of the McNemar test, as appropriate. Association between BNP, NT-pro-BNP, NYHA class, ejection fraction, and LV volumes was estimated by Spearman's correlation. Cumulative survival was estimated by the Kaplan–Meier method. A two-tailed p-value of 0.05 was used to indicate statistical significance. Statistical analyses were performed using SPSS 14.0 (SPSS Inc., Chicago, IL).
|
3. Results
|
|---|
3.1 Operative data
There was no early mortality defined as death within 30 days of the operation or before hospital discharge. All patients underwent SVR by the Dor procedure, and 28 patients had concomitant coronary artery bypass grafting with a mean of 2.8 (1–5) grafts. Mitral valve repair was performed in 4 (14%) patients with preoperative grade III or IV mitral regurgitation. Operative data are summarized in Table 2
.
3.2 Survival and follow-up
All patients were alive at follow-up 6 months postoperatively. However, four patients died later, one renal-transplant recipient died from renal failure 2.1 years after surgery, and two patients died 1.6 and 2.5 years after the operation at age 79 and 74, respectively, both due to heart failure, and one patient died at age 79 due to disseminated bladder cancer 2.8 years after surgery. During a total follow-up of 51 patient-years, survival at 24 months was 93% with 11 patients remaining at risk. Early follow-up for functional assessment and peptide measurements was performed at 6 months postoperatively. Late follow-up was performed at a mean of 21 (standard deviation 9.0, range 12–38) months postoperatively. Preoperative medication included angiotensin converting enzyme inhibitors in 97%, beta-blockers in 93% and spironolactone in 28%. Postoperative medication included angiotensin converting enzyme inhibitors in 97%, beta-blockers in 86% and spironolactone in 34%.
3.2.1 New York heart association functional class
There was a significant improvement in NYHA functional class. Before surgery 22 patients (76%) were in NYHA class III and IV and 6 months after the operation 25 (86%) patients were in NYHA class I and II (p
< 0.001). At late follow-up, two of the four patients who were in NYHA class III at 6 months had died, and two had improved to NYHA class II, and thus, all patients alive (n
= 25) were in NYHA class I and II. Pre- and postoperative NYHA class for all patients is shown in Fig. 1
.
3.2.2 Changes in BNP and NT-pro-BNP
There was a marked and significant reduction of NT-pro-BNP levels (2406 pg/ml vs 1510 pg/ml; p
= 0.03 and 975 pg/ml; p
= 0.03) at 6 months postoperatively, and at late follow-up, respectively. There was a similar reduction of BNP levels (312 pg/ml vs 228 pg/ml; p
= 0.12 and 191 pg/ml; p
= 0.20) at 6 months postoperatively, and at late follow-up, respectively, although not statistically significant. Changes in B-type natriuretic peptide levels are shown in Table 3
. Three patients still in NYHA class III 6 months after surgery were excluded from the statistical analysis at this time-point, since they were non-responders without clinical improvement. In these three patients, there was a six-fold increase in mean BNP and a five-fold increase in mean NT-pro-BNP. All patients with more than 12 months follow-up were included for late analysis, except one who was excluded due to recent onset of atrial fibrillation.
There was a close relationship between BNP and NT-pro-BNP at all time-points (r
= 0.85, n
= 21, p
< 0.001 preoperatively; r
= 0.84, n
= 24, p
< 0.001 6 months postoperatively; r
= 0.93, n
= 20, p
< 0.001 late postoperatively), Fig. 2
. In all patients except one, who developed moderate renal impairment late after surgery, renal function (serum creatinine level) was comparable to baseline.
View larger version (8K):
[in this window]
[in a new window]
|
Fig. 2. BNP plotted on the x-axis against NT-pro-BNP on the y-axis, before (upper graph), at 6 months (middle graph), and late (lower graph) after SVR (r
= 0.85, n
= 21, p
< 0.001 preoperatively; r
= 0.84, n
= 24, p
< 0.001 6 months postoperatively; r
= 0.93, n
= 20, p
< 0.001 late postoperatively). Solid line: estimated regression line and dotted lines: 95% confidence interval.
|
|
3.2.3 Association between functional improvement and reduction of natriuretic peptides
Functional improvement (NYHA class reduction) correlated significantly with reduction in BNP (r
= 0.61, n
= 17, p
= 0.01) and NT-pro-BNP (r
= 0.58, n
= 24, p
= 0.003) levels 6 months after surgery.
3.2.4 Cardiac function
Left ventricular ejection fraction improved from 24% to 37% (p
< 0.001) at 6 months after surgery, assessed by radionuclide ventriculography in 22 patients and by echocardiography in 7 patients. Left ventricular end-diastolic (110 ml/m2 vs 90 ml/m2, p
= 0.009) and end-systolic (75 ml/m2 vs 52 ml/m2, p
= 0.006) volume index according to cardiac MRI decreased significantly, and cardiac index (2.0 l/min/m2 vs 2.5 l/min/m2, p
= 0.003) improved 6 months after surgery, as shown in Table 4
. Cardiac MRI was performed 1–4 weeks before surgery in 18 patients, out of a total of 23 patients who underwent surgery later than October 2003, when cardiac MRI became available to us. Of the 23 patients available for preoperative cardiac MRI, one patient aborted due to panic, two patients were bearers of pacemakers, and two patients could not be referred for logistical reasons. One patient declined postoperative investigation due to claustrophobia, and in the remaining patients, investigation was precluded due to pacemaker (n
= 1) or cardioverter (n
= 2) implantation, and thus repeated investigation was performed 6 months postoperatively in 14 patients.
3.2.5 Association between ejection fraction, ventricular volumes and natriuretic peptides
Increasing ejection fraction correlated significantly with lower BNP (r
= –0.58, n
= 15, p
= 0.02) and NT-pro-BNP (r
= –0.51, n
= 16 p
= 0.04) levels 6 months after surgery (Fig. 3
). Decreasing LV end-systolic volume correlated significantly with lower BNP (r
= 0.65, n
= 11, p
= 0.03) and NT-pro-BNP (r
= 0.62, n
= 12, p
= 0.03) levels 6 months after surgery (Fig. 4
). No significant linear association between peptide levels and ejection fraction or LV volumes was found at baseline.
View larger version (10K):
[in this window]
[in a new window]
|
Fig. 3. BNP (upper graph) and NT-pro-BNP (lower graph) on the y-axis plotted against ejection fraction on the x-axis 6 months after SVR (r
= –0.58, n
= 15, p
= 0.02; r
= –0.51, n
= 16 p
= 0.04, respectively). Solid line: estimated regression line and dotted lines: 95% confidence interval.
|
|
View larger version (10K):
[in this window]
[in a new window]
|
Fig. 4. BNP (upper graph) and NT-pro-BNP (lower graph) on the y-axis plotted against LV end-systolic volume on the x-axis at 6 months after SVR (r
= 0.65, n
= 11, p
= 0.03; r
= 0.62, n
= 12, p
= 0.03, respectively). Solid line: estimated regression line and dotted lines: 95% confidence interval.
|
|
|
4. Discussion
|
|---|
We found that severe heart failure secondary to post-infarction LV remodeling can be reversed by SVR. Significant clinical improvement in these patients was associated with reduced levels of B-type natriuretic peptides 6 months after surgery. Clinical improvement was maintained and peptide levels were further reduced at late follow-up at a mean of 21 months after surgery.
4.1 Surgical ventricular restoration
Previous studies have demonstrated that SVR is safe and improves survival, functional class and LV ejection fraction in patients with post-infarction LV dilation or aneurysm and heart failure [4,12,13]. Moreover, SVR results in LV volume reduction, changes in LV shape, and decreased LV wall stress and mechanical dyssynchrony, which improves systolic and diastolic function [14,15].
4.2 Physiology of BNP and NT-pro-BNP
Brain natriuretic peptide is a hormone released primarily from the cardiac ventricles in response to myocardial wall stress. It is synthesized as an inactive prohormone that is cleaved in equal proportions into the active hormone BNP and the inactive N-terminal fragment (NT-pro-BNP). Both BNP and NT-pro-BNP are constantly released. The main stimulus for increased BNP and NT-pro-BNP secretion is myocardial wall stress but myocardial ischemia is also of importance. In addition, natriuretic peptide synthesis can be increased by tachycardia, glucocorticoids, thyroid hormones, and vasoactive peptides such as endothelin-1 and angiotensin II, independent of the hemodynamic effects of these factors [6]. Natriuretic peptides reduce blood pressure by relaxing vascular smooth muscle and they cause diuresis by increasing glomerular filtration and inhibit sodium reabsorption. BNP block cardiac sympathetic nervous system, and inhibit the renin-angiotensin-aldosterone system. BNP has direct relaxing properties in the myocardium, and might have antiproliferative and antifibrotic effects in vascular tissues. The half-life of BNP is 20 min and the half-life of NT-pro-BNP is 120 min. Accordingly, the serum levels for NT-pro-BNP are approximately six times higher than for BNP. When comparing data from different studies, it is important to acknowledge that peptide measurements obtained with different assays are not comparable and there is no conversion factor for the comparison of BNP and NT-pro-BNP values [7].
4.3 BNP and NT-pro-BNP in heart failure
There is extensive documentation of elevated levels of BNP and NT-pro-BNP in patients with heart failure. In addition, studies have demonstrated an association between severity of heart failure, in terms of NYHA-class, LV systolic and diastolic function, and BNP levels. Also, higher concentrations of these peptides are associated with increased cardiovascular and all-cause mortality in patients with heart failure [6,7,16]. The diagnostic performance of BNP and NT-pro-BNP are considered comparable [7].
4.4 BNP levels after heart failure surgery
A study from the Cleveland Clinic Foundation investigated the effect of left ventricular reconstruction on the level of neuroendocrine activation [17]. Ejection fraction increased by 51% and LV end-diastolic and end-systolic volumes decreased by 36% and 46%, respectively. NYHA class improved in 13 patients and 2 patients had no change. In five patients, plasma levels of BNP were measured before and 3 months after the operation, and mean BNP decreased by 46% from 776 pg/ml to 417 pg/ml (p
= 0.04) [17].
In another recent study, 37 patients with idiopathic dilated cardiomyopathy underwent septal anterior ventricular exclusion procedure and mitral valve procedure for heart failure. Ejection fraction increased from 20.9% to 27.5%, LV dimensions decreased, cardiac index increased, and BNP levels decreased from 975 ± 866 pg/ml to 404 ± 366 pg/ml (p
< 0.05) in 31 hospital survivors 1–6 months after the operation [18].
Due to differences in analytical procedures, direct numerical comparisons between peptide levels found in the above mentioned studies [17,18] and ours are not possible. However, it should be reasonably acceptable to compare the overall reduction in peptide levels. In our study, NT-pro-BNP was reduced by 37% and 51%, and BNP by 20% and 34% 6 months after surgery and at late follow-up, respectively. Thus, natriuretic peptide levels were reduced by about the same magnitude in our study as previously reported after LV reconstruction in heart failure. Further conclusions are precluded due to differences in patient selection (idiopathic vs ischemic cardiomyopathy) and sampling times.
Baseline BNP is an important and independent prognostic marker in patients with heart failure and it has also been demonstrated that changes in BNP over time are associated with corresponding changes in mortality and morbidity [8]. Our results of a consistent decrease in peptide levels were closely correlated to reduction of heart failure symptoms after SVR. Further studies are required to investigate if reduced levels of natriuretic peptides after SVR are associated with better long-term survival.
4.5 Coronary artery bypass surgery
In a study of 31 patients with coronary artery disease, depressed ejection fraction and myocardial viability assessed by stress echocardiography undergoing coronary artery bypass surgery, BNP levels were found to decrease significantly at follow-up 10 months after surgery. The difference between pre- and postoperative BNP levels correlated well with differences in pre- and postoperative LV ejection fraction [19]. Thus, successful coronary artery bypass surgery in patients with impaired LV function was found to improve symptoms and cardiac performance, in correlation with reduced BNP levels.
4.6 Factors affecting natriuretic peptide levels
Previous studies have shown that BNP and NT-pro-BNP are related to age and gender, with higher values in older individuals and in females. Peptide levels are also increased in patients with reduced renal function, and NT-pro-BNP is more affected than BNP by impaired renal function [7]. There were eight patients in our study with impaired renal function, but the majority only had mild impairment. Renal function was stable during follow-up, and therefore we do not consider our results to be confounded by changes in renal function before and after surgery.
4.7 Limitations of the study
Limitations of this study include the relatively small number of patients and the lack of a control group. Moreover, medical therapy for congestive heart failure may have contributed to the reduced natriuretic peptide levels in addition to the surgical therapy. Some patients, for different reasons, declined or could not participate in all parts of the study protocol. Therefore, it was not possible to analyze several important potential associations between patient parameters and peptide levels. Furthermore, the combination of LV reconstruction and coronary artery bypass surgery did not allow for evaluation of the specific role of each procedure.
|
5. Conclusions
|
|---|
In conclusion, we found that sustained reversal of severe heart failure secondary to post-infarction LV remodeling could be achieved after SVR in selected patients. A corresponding decrease in B-type natriuretic peptides was found, both at 6 months and at late follow-up which is suggestive of improved cardiac function and may indicate improved survival.
|
Acknowledgments
|
|---|
This work was supported by grants from the Swedish Heart Lung Foundation and Capio Research Foundation.
|
References
|
|---|
- Gaudron P, Eilles C, Kugler I, Ertl G. Progressive left ventricular dysfunction and remodeling after myocardial infarction. Potential mechanisms and early predictors. Circulation 1993;87:755-763.[Abstract/Free Full Text]
- Pfeffer MA, Braunwald E. Ventricular remodeling after myocardial infarction. Experimental observations and clinical implications. Circulation 1990;81:1161-1172.[Abstract/Free Full Text]
- Menicanti L, Di Donato M. The Dor procedure: what has changed after fifteen years of clinical practice?. J Thorac Cardiovasc Surg 2002;124:886-890.[Free Full Text]
- Athanasuleas CL, Buckberg GD, Stanley AWH, Siler W, Dor V, Di Donato M, Menicanti L, Almeida de Oliveira S, Beyersdorf F, Kron IL. Surgical ventricular restoration in the treatment of congestive heart failure due to post-infarction ventricular dilation. J Am Coll Cardiol 2004;44:1439-1445.[Abstract/Free Full Text]
- Sartipy U, Albåge A, Strååt E, Insulander P, Lindblom D. Surgery for ventricular tachycardia in patients undergoing left ventricular reconstruction by the Dor procedure. Ann Thorac Surg 2006;81:65-71.[Abstract/Free Full Text]
- de Lemos JA, McGuire DK, Drazner MH. B-type natriuretic peptide in cardiovascular disease. Lancet 2003;362:316-322.[CrossRef][Medline]
- Weber M, Hamm C. Role of B-type natriuretic peptide (BNP) and NT-proBNP in clinical routine. Heart 2006;92:843-849.[Free Full Text]
- Anand IS, Fisher LD, Chiang Y-T, Latini R, Masson S, Maggioni AP, Glazer RD, Tognoni G, Cohn JN. For the Val-He FTI. Changes in brain natriuretic peptide and norepinephrine over time and mortality and morbidity in the valsartan heart failure trial (Val-HeFT). Circulation 2003;107:1278-1283.[Abstract/Free Full Text]
- Sartipy U, Albåge A, Lindblom D. The Dor procedure for left ventricular reconstruction. Ten-year clinical experience. Eur J Cardiothorac Surg 2005;27:1005-1010.[Abstract/Free Full Text]
- Maisano F, Torracca L, Oppizzi M, Stefano PL, D’Addario G, La Canna G, Zogno M, Alfieri O. The edge-to-edge technique: a simplified method to correct mitral insufficiency. Eur J Cardiothorac Surg 1998;13:240-245.[Abstract/Free Full Text]
- Menicanti L, Di Donato M, Frigiola A, Buckberg G, Santambrogio C, Ranucci M, Santo D. Ischemic mitral regurgitation: intraventricular papillary muscle imbrication without mitral ring during left ventricular restoration. J Thorac Cardiovasc Surg 2002;123:1041-1050.[Abstract/Free Full Text]
- Dor V, Sabatier M, Di Donato M, Maioli M, Toso A, Montiglio F. Late hemodynamic results after left ventricular patch repair associated with coronary grafting in patients with postinfarction akinetic or dyskinetic aneurysm of the left ventricle. J Thorac Cardiovasc Surg 1995;110:1291-1301.[Abstract/Free Full Text]
- Di Donato MDM, Sabatier, MDM, Dor, MDV, Toso, MDA, Maioli, MDM. Akinetic versus dyskinetic postinfarction scar: relation to surgical outcome in patients undergoing endoventricular circular patch plasty repair. J Am Coll Cardiol 1997;29:1569-1575.[Abstract]
- Di Donato M, Toso A, Dor V, Sabatier M, Barletta G, Menicanti L, Fantini F. The RG. Surgical ventricular restoration improves mechanical intraventricular dyssynchrony in ischemic cardiomyopathy. Circulation 2004;109:2536-2543.[Abstract/Free Full Text]
- Tulner SAF, Steendijk P, Klautz RJM, Bax JJ, Schalij MJ, van der Wall EE, Dion RAE. Surgical ventricular restoration in patients with ischemic dilated cardiomyopathy: evaluation of systolic and diastolic ventricular function, wall stress, dyssynchrony, and mechanical efficiency by pressure-volume loops. J Thorac Cardiovasc Surg 2006;132:610-620.[Abstract/Free Full Text]
- Kragelund C, Gronning B, Kober L, Hildebrandt P, Steffensen R. N-terminal Pro-B-type natriuretic peptide and long-term mortality in stable coronary heart disease. N Engl J Med 2005;352:666-675.[Abstract/Free Full Text]
- Schenk S, McCarthy PM, Starling RC, Hoercher KJ, Hail, MD, Ootaki Y, Francis GS, Doi K, Young JB, Fukamachi K. Neurohormonal response to left ventricular reconstruction surgery in ischemic cardiomyopathy. J Thorac Cardiovasc Surg 2004;128:38-43.[Abstract/Free Full Text]
- Suma H, Isomura T, Horii T, Nomura F. Septal anterior ventricular exclusion procedure for idiopathic dilated cardiomyopathy. Ann Thorac Surg 2006;82:1344-1348.[Abstract/Free Full Text]
- Chello M, Mastroroberto P, Perticone F, Cirillo F, Bevacqua E, Olivito S, Covino E. Plasma levels of atrial and brain natriuretic peptides as indicators of recovery of left ventricular systolic function after coronary artery bypass. Eur J Cardiothorac Surg 2001;20:140-146.[Abstract/Free Full Text]
Top
Abstract
1. Introduction
