CLINICAL STUDY
Echocardiographic prediction ofleft ventricular dysfunction aftermitral valve repair for mitral regurgitation as anindicator to decide the optimal timing of repair
Takayoshi Matsumura, MD*,
Eiji Ohtaki, MD*,*,
Kaoru Tanaka, MD*,
Kazuhiko Misu, MD*,
Tetsuya Tobaru, MD*,
Ryuta Asano, MD*,
Masatoshi Nagayama, MD*,
Koichi Kitahara, MD*,
Jun Umemura, MD*,
Tetsuya Sumiyoshi, MD*,
Hitoshi Kasegawa, MD and
Saichi Hosoda, MD*
* Department of Cardiology, Sakakibara Heart Institute, Tokyo, Japan
Department of Cardiovascular Surgery, Sakakibara Heart Institute, Tokyo, JapanFinancial support was given by the Japan Research Promotion Society for Cardiovascular Diseases.
Manuscript received October 28, 2002;
revised manuscript received February 24, 2003,
accepted March 7, 2003.
* Reprint requests and correspondence: Dr. Eiji Ohtaki, Department of Cardiology, Sakakibara Heart Institute, 2-5-4, Yoyogi, Shibuya-ku, Tokyo 151-0053, Japan.
eohtaki{at}shi.heart.or.jp
 |
Abstract
|
|---|
OBJECTIVES: This study sought to determine whether echocardiography before mitral valve repair (MVR) for mitral regurgitation (MR) was predictive of postoperative left ventricular (LV) dysfunction and useful for deciding the optimal timing of repair.
BACKGROUND: Some reports have shown that the preoperative echocardiographic data of left ventricular ejection fraction (LVEF) and left ventricular end-systolic diameter (LVDs) were good predictors of postoperative LV dysfunction. However, few reports were based on long-term follow-up data of large numbers of patients who underwent MVR in the last decade.
METHODS: A total of 274 patients with moderate or severe MR underwent MVR between October 1, 1991, and September 30, 2000. Among them, 171 patients who had both an operation for isolated MR due to degenerative pathology and a postoperative echocardiogram were studied. Postoperative echocardiograms were performed 3.9 ± 2.4 years after the operation.
RESULTS: The LVEF decreased from 66 ± 10% before surgery to 63 ± 11% after surgery (p < 0.0001). On univariate analysis, preoperative LVEF and LVDs correlated with postoperative LVEF (r = 0.41 and r = –0.39, respectively). Overall, postoperative LV dysfunction (defined as LVEF <50%) was not frequent (12%). However, the incidence of postoperative LV dysfunction was high in patients with preoperative LVEF <55% (38%) or LVDs  40 mm (23%).
CONCLUSIONS: In patients with MR, the echocardiographic data of LVEF and LVDs were good predictors of postoperative LV dysfunction. When a decrease in LVEF or an increase in LVDs is detected, MVR should be considered to preserve postoperative LV function.
|
Abbreviations and Acronyms
| | ACC/AHA | | American College of Cardiology/American Heart Association | | ePTFE | | expanded polytetrafluoroethylene | | LV | | left ventricle/ventricular | | LVDd | | left ventricular end-diastolic diameter | | LVDs | | left ventricular end-systolic diameter | | LVEF | | left ventricular ejection fraction | | MR | | mitral regurgitation | | MVR | | mitral valve repair | | NYHA | | New York Heart Association |
|
The effectiveness of mitral valve repair (MVR) for patients with mitral regurgitation (MR) is well established (1–8). This advent has led to earlier surgical intervention to correct MR, because deferring surgery until the patient becomes symptomatic or manifests overt left ventricular (LV) dysfunction often leads to irreversible LV dysfunction after the operation (3,6,8–11).
Some reports have shown that preoperative echocardiographic data, especially left ventricular ejection fraction (LVEF) and left ventricular end-systolic diameter (LVDs), were good predictors of survival (12–14) and postoperative LV dysfunction (3,5,12,13,15) and useful in clinical decision-making on the timing of surgery. Some previous reviews (6,8) and the American College of Cardiology/American Heart Association (ACC/AHA) guidelines (7) recommend MVR even without symptoms if the LVEF falls to lower than 60% or LVDs increases to over 45 mm.
However, few reports on this issue were based on long-term follow-up data of large series of MVR alone (excluding valve replacement) conducted in the last decade. The purpose of this study was to determine whether echocardiographic measures were predictive of LV dysfunction after MVR and useful in deciding the optimal timing of repair, by analyzing a large series of patients who had the operation in the 1990s, with relatively long-term follow-up data.
|
Methods
|
|---|
Patients.
Between October 1, 1991, and September 30, 2000, 274 patients with moderate or severe MR, age 20 years or above, with no concomitant mitral stenosis, underwent MVR at our institution. The etiologies of regurgitation are shown in Table 1. The 224 patients with regurgitation due to degenerative pathology were considered possible candidates for this study.
Among them, 23 patients were excluded because of concomitant surgical procedures, including coronary artery bypass grafting (n = 6), aortic valve replacements or plasty (n = 12), closure of atrial septum defects (n = 2), closure of ventricular septum defects (n = 2), and Bentall’s procedure (n = 1). Those who underwent concomitant tricuspid annuloplasty, tricuspid valve plasty, left atrial plication, or the Maze procedure were included.
Among the remaining 201 patients, 9 (4%) were confirmed to be unsuitable for MVR intraoperatively and converted to mitral valve replacement during the same operation. First, the other 192 patients comprised our study population for patient survival and reoperations. After excluding those without postoperative echocardiographic data at least six months after operation, 171 patients were included in the analysis of postoperative LV dysfunction.
The mean age of the patients was 54 ± 13 years (range 22 to 77 years ), and 107 (63%) were men. Before surgery, 43 patients were in New York Heart Association (NYHA) functional class I, 84 patients were in class II, 40 were in class III, and 4 were in class IV. Among 21 patients without echocardiographic data at least six months after the operation, the mean age was higher (64 ± 9 years, p = 0.001), and 9 (43%) were men. There was no significant difference in preoperative LVEF between patients with and without follow-up echocardiographic data (66 ± 10% vs. 62 ± 12%, p = 0.07).
Surgical procedures.
Prolapse of the posterior leaflet was repaired with sliding plasty or resection/suture in most cases, and some required chordal replacement with expanded polytetrafluoroethylene (ePTFE) sutures. Most cases of prolapse of the anterior leaflet were managed with ePTFE sutures (16). The majority of patients also had a ring annuloplasty. Since February 1996, we have been performing physiologic remodeling annuloplasty, which we developed to retain the shape of the anterior leaflet (17). Since 1993, intraoperative transesophageal echocardiography has been routinely performed, and repair was redone when more than mild regurgitation was detected.
Echocardiographic examinations.
Postoperative echocardiographic examinations were performed during a follow-up period of 3.9 ± 2.4 years after the operation. For those patients who died or underwent reoperation during the follow-up period, the latest echocardiographic data before death or the secondary surgical intervention was used. The LVEF was calculated by the Teichholz formula from M-mode recordings (18).
Statistical analysis.
All data are expressed as means ± SD. A comparison of variables between patients with and without follow-up echocardiographic data and variables before and after MVR was performed by the Student paired t test. The survival rate and survival free of reoperation were estimated by the Kaplan-Meier method. Simple linear regression analysis was used to determine the relationship between preoperative clinical or echocardiographic variables and postoperative LVEF. Stepwise selection multiple regression analysis was used to study multivariate models to predict a postoperative LVEF with significant univariate predictors, with the criterion for inclusion being p < 0.20. The Mann-Whitney U test was used to compare the incidence of LV dysfunction according to more than two classes of preoperative variables. The difference in the incidence between two groups was evaluated using the Fisher exact test. Logistic regression analysis was used to predict postoperative LV dysfunction with preoperative echocardiographic variables. All comparisons were two-tailed.
|
Results
|
|---|
Patient survival and reoperations.
Among the 192 patients, 14 died during the follow-up period of 4.1 ± 2.5 years. Five patients died before being discharged within 90 days after the procedures: four due to pneumonia and one due to septic shock. Nine late deaths occurred: five due to cerebrovascular disease, two due to congestive heart failure, and two due to malignant disease. The survival rate after MVR was 97% at one year and 92% at five years. In addition, three patients required secondary MVR, and eight patients underwent mitral valve replacement during the follow-up period. Survival free of reoperation was 99% at one year and 94% at five years.
Comparison of preoperative and postoperative echocardiographic variables.
After MVR, both LVDd and LVDs decreased significantly (Table 2). The decrease was much greater for LVDd than for LVDs; thus, the LVEF also decreased significantly from 66 ± 10% to 63 ± 11% (p < 0.0001).
Univariate associations between preoperative echocardiographic variables and postoperative LVEF.
On univariate analysis, the preoperative LVEF was most predictive of postoperative LVEF (Table 3, Fig. 1). Preoperative LVDs also significantly correlated with postoperative LVEF (Fig. 2). The univariate correlation between preoperative LVDd and postoperative LVEF was weaker (Fig. 3). There was no significant relationship between the age at operation or NYHA class and postoperative LVEF.
View this table:
[in this window]
[in a new window]
|
Table 3 Univariate Correlation of Postoperative Ejection Fraction With Preoperative Clinical or Echocardiographic Variables
|
|
View larger version (22K):
[in this window]
[in a new window]
|
Figure 2 Correlation between preoperative left ventricular end-systolic diameter (LVDs) and postoperative left ventricular ejection fraction (LVEF).
|
|
View larger version (24K):
[in this window]
[in a new window]
|
Figure 3 Correlation between preoperative left ventricular end-diastolic diameter (LVDd) and postoperative left ventricular ejection fraction (LVEF).
|
|
Multivariate associations between preoperative echocardiographic variables and postoperative LVEF.
Multiple regression analysis with preoperative echocardiographic variables was performed to predict a postoperative LVEF. The two best models were:
(R2 = 0.179, p < 0.0001) and
(R2 = 0.175, p < 0.0001)
where "post" and "pre" represent "postoperative" and "preoperative," respectively.
Although univariate analysis showed that preoperative LVDs was more predictive than preoperative LVDd, the model with preoperative LVEF and LVDd had a little higher coefficient of determination than the model with preoperative LVEF and LVDs. This is mainly because a higher correlation coefficient between preoperative LVEF and LVDs (r = –0.81) reduces the additional predictive value of LVDs in relation to LVEF, and this does not necessarily mean that LVDd is a better predictor than LVDs.
Incidence of postoperative LV dysfunction.
The overall postoperative LV dysfunction (defined as LVEF <50%) was not frequent (12%). However, among patients with a low LVEF before surgery, the incidence of postoperative LV dysfunction was higher (p = 0.0013, Table 4). Similarly, those with a larger LVDs before surgery had a tendency to have LV dysfunction after surgery (p = 0.006, Table 5).
Table 6 shows that patients with an LVEF <55% or an LVDs 40 mm before surgery had a higher risk of LV dysfunction after surgery (p = 0.0007 or p = 0.0019, respectively). Even with a preoperative LVEF 55%, 14% of patients had postoperative LV dysfunction when their preoperative LVDs was 40 mm or above, although logistic regression analysis showed no significant additional predictive value of preoperative LVDs 40 mm with LVEF <55%, compared with LVEF <55% alone, with a relatively low p value (p = 0.1282).
|
Discussion
|
|---|
In chronic MR, increased preload and reduced afterload due to unloading from the LV into the left atrium facilitate LV ejection. Therefore, the LVEF is maintained in the lower normal range, and patients remain in an asymptomatic state even in the presence of LV dysfunction (7,9). Thus, deferring surgical intervention for too long often leads to irreversible postoperative LV dysfunction (3,6,8–11).
Previous reports have shown that NYHA classification was a good predictor of postoperative survival (14,19) and myocardial failure (3,5). However, the evaluation is subjective, and many people feel only mildly symptomatic because they limit their own activity unconsciously. Thus, a noninvasive and objective echocardiographic examination, which can be done repeatedly, is needed to guide the optimal timing of surgical intervention. Moreover, to determine the timing, we must take into consideration not only postoperative survival but also the incidence of postoperative LV dysfunction. It may be a matter of controversy whether a patient who has slight LV dysfunction but becomes asymptomatic should be recognized to have a bad clinical outcome. However, we studied objective postoperative echocardiographic data, not subjective postoperative symptoms, as the major measure of outcome.
Enriquez-Sarano et al. (15) studied 162 patients with MVR and 104 patients with mitral valve replacement between 1980 and 1989. They reported that preoperative LVEF and LVDs were independent predictors of postoperative LVEF and that surgical correction should be strongly considered in patients with an LVEF <60% or with an LVEF over 60% and an LVDs approaching 45 mm. In another study of 288 patients with MVR and 288 patients with valve replacement, they concluded that the incidence of congestive heart failure was very high in patients with an LVEF <50% and that the incidence was also increased in patients with an LVEF between 50% and 59% (3). Lee et al. (5) studied 167 patients with MVR and 111 patients with mitral valve replacement between 1987 and 1994 and reported that the risk of postoperative myocardial failure was markedly increased when the preoperative LVEF was <40%. In a study of 61 patients with rheumatic MR who were followed up after mitral valve replacement, Wisenbaugh et al. (13) reported that a good outcome was predicted at a preoperative LVDs of 40 mm. Flemming et al. (20) found in a study of 27 patients that an LVDs over 40 mm might be useful for identifying patients with MR and occult LV dysfunction.
However, among the aforementioned studies that examined whether echocardiographic data were predictive of postoperative LV dysfunction, some were based on series composed entirely (12,13) or partially (3,5,15,20) of mitral valve replacement or patients who had an operation in the 1980s (3,15). Others were based on data with a mean follow-up period less than two years (12,20) or data from a small number of patients (12,13,20). The feature of this study is its longer follow-up data of a larger series of MVR conducted in the 1990s.
In our institute, most patients with degenerative MR who need surgical intervention undergo MVR, even with prolapse of the anterior leaflet. Our series showed excellent mid-term results with a good survival rate and survival free of reoperation after MVR.
In the present study, LVDs decreased significantly after surgery, which would imply increased contractility, decreased afterload, or both. Postoperative afterload usually increases with correction of MR, and decreased LVDs is considered to reflect increased LV contractility. The LVEF decreased significantly after surgery, which is consistent with previous studies (4,15). The decrease must be due mainly to a decrease in preload after surgical correction of MR and does not necessarily indicate true impairment of LV systolic performance.
The overall frequency of postoperative LV dysfunction was relatively low (12%) in our series. This may be the result of advances in surgical techniques and the earlier timing of operations at our institute. However, the patients with a lower LVEF or larger LVDs before surgery tended to have postoperative LV dysfunction. In particular, those with LVEF <55% or LVDs 40 mm before surgery had a significantly higher incidence of LV dysfunction after surgery.
Symptomatic patients refractory to appropriate medical therapy obviously require surgery even when LV function is apparently normal (3,5,6,8,14,18,21). In addition, our study suggests that patients with LVEF <55% or LVDs 40 mm are also candidates for repair, considering the lower operative mortality rate in recent years (4,19,22,23). Furthermore, the advances of transthoracic and transesophageal echocardiography have made it easy to determine the feasibility of valve repair before surgery.
We found that an LVEF of 55% and an LVDs of 40 mm identified Japanese patients with a higher risk of postoperative LV dysfunction, and both values were lower than those recommended in the ACC/AHA guidelines (7). These echocardiographic measures in Japanese patients may not be applied directly to patients in other countries, because the normal size of the heart may be different. Nevertheless, these data collectively confirm that the echocardiographic data on LVEF and LVDs are good predictors of postoperative LV dysfunction and are useful in deciding the optimal timing of MVR.
Study limitations.
In this study, we defined LV dysfunction as LVEF <50%, according to Enriquez-Sarano et al. (15). However, postoperative LV performance is not determined by LVEF alone. We studied postoperative LVEF, which was easy to measure, but it is only one aspect of LV performance. We did not take into account the effect of medications that reduce LV contractility and the influence of residual MR.
In addition, we included only those patients with degenerative mitral valve disease. Patients with MR due to rheumatic disease are usually less feasible for MVR and more likely to require conversion to mitral valve replacement intraoperatively, even though MVR is expected preoperatively. Also, their LV performance after valve repair is less known. It is still controversial as to when to recommend surgery for an asymptomatic patient with a rheumatic valve that is expected to be repairable.
Conclusions.
Our study of a large series of patients who had an operation in the 1990s, with long-term follow-up data, shows that the echocardiographic parameters of LVEF and LVDs are good predictors of postoperative LV dysfunction and useful as objective markers to decide the timing of surgery. Considering the lower operative mortality rate in recent years, when a slight decrease in LVEF or a slight increase in LVDs is detected on an echocardiogram of a patient with degenerative MR, early surgical intervention with MVR should be considered to preserve LV function after surgery.
|
References
|
|---|
1. Akins CW, Hilgenberg AD, Buckley MJ, et al. Mitral valve reconstruction versus replacement for degenerative or ischemic mitral regurgitation. Ann Thorac Surg. 1994;58:668–675[Abstract]
2. Corin WJ, Sutsch GG, Murakami T, Krogmann ON, Turina M, Hess OM. Left ventricular function in chronic mitral regurgitation: preoperative and postoperative comparison. J Am Coll Cardiol. 1995;25:113–121[Abstract]
3. Enriquez-Sarano M, Schaff HV, Orszulak TA, Bailey KR, Tajik AJ, Frye RL. Congestive heart failure after surgical correction of mitral regurgitation: a long-term study. Circulation. 1995;92:2496–2503[Abstract/Free Full Text]
4. Enriquez-Sarano M, Schaff H, Orszulak TA, Tajik AJ, Bailey KR, Frye RL. Valve repair improves the outcome of surgery for mitral regurgitation. Circulation. 1995;91:1022–1028[Abstract/Free Full Text]
5. Lee EM, Shapiro LM, Wells FC. Superiority of mitral valve repair in surgery for degenerative mitral regurgitation. Eur Heart J. 1997;18:655–663[Abstract/Free Full Text]
6. Carabello BA, Crawford FA. Medical progress: valvular heart disease. N Engl J Med. 1997;337:32–41[Free Full Text]
7. ACC/AHA guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 1998;32:1486–1588 (Committee on Management of Patients with Valvular Heart Disease)[Free Full Text]
8. Otto CM. Clinical practice: evaluation and management of chronic mitral regurgitation. N Engl J Med. 2001;345:740–746[Free Full Text]
9. Starling MR, Kirsh MM, Montgomery DG, Gross MD. Impaired left ventricular contractile function in patients with long-term mitral regurgitation and normal ejection fraction. J Am Coll Cardiol. 1993;22:239–250[Abstract]
10. Starling MR. Effects of valve surgery on left ventricular contractile function in patients with long-term mitral regurgitation. Circulation. 1995;92:811–818[Abstract/Free Full Text]
11. Ling LH, Enriquez-Sarano M, Seward JB, et al. Early surgery in patients with mitral regurgitation due to flail leaflets: a long-term outcome study. Circulation. 1997;96:1819–1825[Abstract/Free Full Text]
12. Crawford MH, Souchek J, Oprian CA, et al. Determinants of survival and left ventricular performance after mitral valve replacement: Department of Veterans Affairs Cooperative Study on Valvular Heart Disease. Circulation. 1990;81:1173–1181[Abstract/Free Full Text]
13. Wisenbaugh T, Skudicky D, Sareli P. Prediction of outcome after valve replacement for rheumatic mitral regurgitation in the era of chordal preservation. Circulation. 1994;89:191–197[Abstract/Free Full Text]
14. Enriquez-Sarano M, Tajik AJ, Schaff HV, Orszulak TA, Bailey KR, Frye RL. Echocardiographic prediction of survival after surgical correction of organic mitral regurgitation. Circulation. 1994;90:830–837[Abstract/Free Full Text]
15. Enriquez-Sarano M, Tajik AJ, Schaff HV, et al. Echocardiographic prediction of left ventricular function after correction of mitral regurgitation: results and clinical implications. J Am Coll Cardiol. 1994;24:1536–1543[Abstract]
16. Kasegawa H, Kamata S, Hirata S, et al. Simple method for determining proper length of artificial chordae in mitral valve repair. Ann Thorac Surg. 1994;57:237–239[Abstract]
17. Kasegawa H, Kamata S, Ida T, Kawase M, Fujimoto T, Umezu M. Physiologic remodeling annuloplasty to retain the shape of the anterior leaflet: a new concept in mitral valve repair. J Heart Valve Dis. 1997;6:604–607[Medline]
18. Teichholz LE, Kreulen T, Herman MV, Gorlin R. Problems in echocardiographic volume determinations: echocardiographic-angiographic correlations in the presence or absence of asynergy. Am J Cardiol. 1976;37:7–11[CrossRef][Medline]
19. Tribouilloy CM, Enriquez-Sarano M, Schaff HV, et al. Impact of preoperative symptoms on survival after surgical correction of organic mitral regurgitation: rationale for optimizing surgical indications. Circulation. 1999;99:400–405[Abstract/Free Full Text]
20. Flemming MA, Oral H, Rothman ED, Briesmiester K, Petrusha JA, Starling MR. Echocardiographic markers for mitral valve surgery to preserve left ventricular performance in mitral regurgitation. Am Heart J. 2000;140:476–482[CrossRef][Medline]
21. Ling LH, Enriquez-Sarano M, Seward JB, et al. Clinical outcome of mitral regurgitation due to flail leaflet. N Engl J Med. 1996;335:1417–1423[Abstract/Free Full Text]
22. Sousa UM, Dreyfus G, Rescigno G, et al. Surgical treatment of asymptomatic and mildly symptomatic mitral regurgitation. J Thorac Cardiovasc Surg. 1996;112:1240–1248[Abstract/Free Full Text]
23. Smolens IA, Pagani FD, Deeb GM, Prager RL, Sonnad SS, Bolling SF. Prophylactic mitral reconstruction for mitral regurgitation. Ann Thorac Surg. 2001;72:1210–1216[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
R. M. Suri, H. V. Schaff, J. A. Dearani, T. M. Sundt, R. C. Daly, C. J. Mullany, M. Enriquez-Sarano, and T. A. Orszulak
Recovery of left ventricular function after surgical correction of mitral regurgitation caused by leaflet prolapse.
J. Thorac. Cardiovasc. Surg.,
May 1, 2009;
137(5):
1071 - 1076.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R.-M. B.G.E. Breukers, R. J. Trof, R. B.P. de Wilde, P. C.M. van den Berg, J. W.R. Twisk, J. R.C. Jansen, and J. Groeneveld
Relative value of pressures and volumes in assessing fluid responsiveness after valvular and coronary artery surgery
Eur. J. Cardiothorac. Surg.,
January 1, 2009;
35(1):
62 - 68.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. M. Suri, H. V. Schaff, J. A. Dearani, T. M. Sundt III, R. C. Daly, C. J. Mullany, M. E. Sarano, and T. A. Orszulak
Determinants of early decline in ejection fraction after surgical correction of mitral regurgitation.
J. Thorac. Cardiovasc. Surg.,
August 1, 2008;
136(2):
442 - 447.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. A. Carabello
The Current Therapy for Mitral Regurgitation
J. Am. Coll. Cardiol.,
July 29, 2008;
52(5):
319 - 326.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. G. Neilan, T.-T. Ton-Nu, Y. Kawase, R. Yoneyama, K. Hoshino, F. del Monte, R. J. Hajjar, M. H. Picard, R. A. Levine, and J. Hung
Progressive nature of chronic mitral regurgitation and the role of tissue Doppler-derived indexes
Am J Physiol Heart Circ Physiol,
May 1, 2008;
294(5):
H2106 - H2111.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. O'Gara, L. Sugeng, R. Lang, M. Sarano, J. Hung, S. Raman, G. Fischer, B. Carabello, D. Adams, and M. Vannan
The role of imaging in chronic degenerative mitral regurgitation.
J. Am. Coll. Cardiol. Img.,
March 1, 2008;
1(2):
221 - 237.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Enriquez-Sarano, V. T. Nkomo, and H. Michelena
Principles and Practice of Echocardiography in Cardiac Surgery
Card. Surg. Adult,
January 1, 2008;
3(2008):
315 - 348.
[Full Text]
|
|
|
|
|
|
|
T. Gudbjartsson, T. Absi, and S. Aranki
Mitral Valve Replacement
Card. Surg. Adult,
January 1, 2008;
3(2008):
1031 - 1068.
[Full Text]
|
|
|
|
|
|
|
R. M. Suri, H. V. Schaff, J. A. Dearani, T. M. Sundt III, R. C. Daly, C. J. Mullany, M. Enriquez-Sarano, and T. A. Orszulak
Recurrent mitral regurgitation after repair: Should the mitral valve be re-repaired?
J. Thorac. Cardiovasc. Surg.,
December 1, 2006;
132(6):
1390 - 1397.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. R. Essop and V. T. Nkomo
Rheumatic and Nonrheumatic Valvular Heart Disease: Epidemiology, Management, and Prevention in Africa
Circulation,
December 6, 2005;
112(23):
3584 - 3591.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Eguchi, E. Ohtaki, T. Matsumura, K. Tanaka, T. Tohbaru, N. Iguchi, K. Misu, R. Asano, M. Nagayama, T. Sumiyoshi, et al.
Pre-operative atrial fibrillation as the key determinant of outcome of mitral valve repair for degenerative mitral regurgitation
Eur. Heart J.,
September 2, 2005;
26(18):
1866 - 1872.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. A. Carabello
Is it ever too late to operate on the patient with valvular heart disease?
J. Am. Coll. Cardiol.,
July 21, 2004;
44(2):
376 - 383.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. R. Essop
Predictors of left ventricular dysfunction following mitral valve repair for mitral regurgitation
J. Am. Coll. Cardiol.,
May 19, 2004;
43(10):
1925 - 1925.
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Matsumura, E. Ohtaki, K. Tanaka, K. Misu, T. Tohbaru, R. Asano, M. Nagayama, K. Kitahara, J. Umemura, T. Sumiyoshi, et al.
Predictors of left ventricular dysfunction following mitral valve repair for mitral regurgitation: Reply
J. Am. Coll. Cardiol.,
May 19, 2004;
43(10):
1925 - 1926.
[Full Text]
[PDF]
|
|
|
|
Top
Abstract
Methods
