PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of f1000medLatest ContentReportsReportsReports
 
F1000 Med Rep. 2009; 1: 98.
Published online 2009 December 15. doi:  10.3410/M1-98
PMCID: PMC2948327

Prognostic value of echocardiography with particular reference to patients with valvular heart disease

Abstract

Echocardiography is comparatively inexpensive relative to other modern cardiovascular imaging tools. It is widely available, even in poor countries, and provides a comprehensive evaluation of cardiac structure and function. It is an ideal tool for the evaluation of patients with valvular heart disease and provides important prognostic information. This review of recent literature highlights reports on outcomes data and provides a clinically valuable summary in table format.

Introduction and context

The diagnostic criteria for echocardiographic assessment of valvular heart disease are well established [1]. An ever-growing preponderance of literature highlights the usefulness of echocardiography as a prognostic indicator for outcomes in valvular heart disease, particularly aortic valve (AV) and mitral valve (MV) disorders. This review focuses on recent published reports that are intended to provide the physician with the necessary data to transition from an anatomic report to a more prognostic report in an effort to improve patient management choices.

Recent advances

Aortic stenosis

A preoperative left ventricular (LV) end-systolic index of less than 27.5 mm/m2 as measured by echocardiography has been shown to be a strong predictor of good intermediate LV recovery following aortic valve replacement (AVR) surgery for severe aortic stenosis (AS) [2].

Furthermore, prior to AVR, an extremely poor (21%) 2-year event-free survival can be expected in asymptomatic patients with mostly calcific AS and a peak gradient of greater than 64 mm Hg (peak Doppler velocity >4.0 m/s) [3]. This point emphasizes the critical role of serial echocardiography and clinical evaluation of these patients. In patients with a bicuspid AV, a peak gradient of at least 80 mm Hg and an aortic valve area (AVA) of not more than 0.75 cm2 have been shown to predict the need for urgent AV surgery [4].

In patients with AS and normal left ventricular ejection fraction (LVEF), mitral annular tissue Doppler imaging (TDI) correlates significantly with AVA and amino-terminal pro-B-type natriuretic peptide (BNP) levels. Mortality and the need for AVR are better predicted by a reduced septal annular diastolic atrial velocity (A′) of less than 9.6 cm/s than with AVA or BNP [5]. In patients with AS and reduced LV contractility, a critical understanding of LV contractile reserve (CR) is required if the mean AV gradient is low (<30 mm Hg). In these patients, low-dose dobutamine infusion (up to 20 μg/kg per minute) allows the differentiation between patients with true severe (fixed) AS who will benefit from AVR from those with either nonsevere (relative) AS or a late-stage (nonviable) cardiomyopathy for whom AVR may be harmful. In a multicenter prospective evaluation of patients with AS (AVA of approximately 0.7 cm2) and a low AV gradient (mean of approximately 29 mm Hg), those with a 20% increase in LV stroke volume during dobutamine infusion had an operative mortality significantly lower than those without (5% versus 32%) [6]. Furthermore, a lack of CR or a very low mean gradient (<20 mm Hg) was a multivariate predictor of operative mortality, with odds ratios of 10.9 and 4.7, respectively.

Proper prosthesis selection is of crucial importance in preventing prosthesis patient mismatch (PPM), an independent predictor of mortality after AVR [7]. Recently, transcatheter AVR has become possible and will certainly be advanced in subsequent years. Outcomes in these patients are variable, and the need for permanent pacemaker insertion is not uncommon. Recently, this has been predicted by two simple two-dimensional echocardiography (2DE) features: severe septal hypertrophy (>17 mm) and baseline thickness of the native noncoronary cusp (>8 mm) as measured by transesophageal echocardiography (TEE) [8].

Aortic regurgitation

In the setting of aortic regurgitation (AR), current guidelines recommend surgery for asymptomatic patients with a maximal left ventricular end-diastolic diameter (LVDd) of greater than 55 mm or an LVEF of less than 50% [9]. This stems from the knowledge that outcomes worsen when these values are exceeded. Use of an indexed LVDd of less than 25 mm/m2 in patients with a body surface area (BSA) of not more than the 25th percentile (BSA of 1.43-1.68 m2) is associated with a drop in age-adjusted mortality and is also a better prognostic indicator for unfavorable outcomes 1 year after surgery as measured by an LVEF of less than 50% [10]. Asymptomatic patients with severe quantitative AR [an effective regurgitant orifice (ERO) of >35 mm2, a regurgitant volume of >60 mL, or a regurgitant fraction percentage of >50%] and normal LVEF (>50%) have a greater than fivefold increase in mortality. Furthermore, cardiac events at 10 years were 90% with an end-systolic volume index (ESVI) of greater than 45 mL/m2 but only 40% with an ESVI of less than 45 mL/m2 [11].

Mitral valve disease

Functional mitral regurgitation (MR) due to left ventricular dysfunction is associated with a poor outcome when the MR is quantified as more than mild (ERO >20 mm2) and the left ventricular end-systolic volume is increased at rest (>95 mL/m2) or after exercise (left ventricular end-diastolic volume >120 mL/m2) [11]. In patients with MV prolapse, outcomes can be predicted simply via the serial progression of demonstrated MR, regardless of age, gender, prolapse location, valve thickening, or pre-existing MR [12]. Increases in MR by greater than 1 MR grade are associated with left atrial and ventricular dilatation and an overall poor prognosis.

Flail leaflet plays a major role in the etiology of organic MR. In addition, the presence of flail leaflet is a poor prognostic indicator, with much of this patient population dying or requiring surgery within 10 years of receiving the diagnosis [13]. Early surgery, particularly MV repair, in both the symptomatic and asymptomatic patient population has been shown to reduce the rates of cardiac events [14]. However, the recurrence of 2/4 grade or worse MR in patients undergoing MV repair for flail leaflet is between 2% and 4% per year [15]. The use of real-time three-dimensional echocardiography (RT3DE) permits direct analysis of mitral annular geometry and precise quantitative analysis of leaflet geometry. This tool holds great promise in improving our understanding of flail leaflet in MR as well as enhancing the surgical precision in techniques used for repair [15].

Patients may develop LV dysfunction (EF <50%) after MV surgery. Large preoperative MR volumes (≥80 mL) are strongly associated with unexpected postoperative LV dysfunction and are useful in the timing of surgical intervention in asymptomatic patients [16]. A mitral E/E′ (early mitral filling velocity/early diastolic mitral annular velocity) ratio of greater than 13.5 as determined by the average septal and lateral mitral annular TDI velocities predicts a twofold worse event-free survival, particularly in patients with severe secondary MR due to heart failure [17]. In patients with asymptomatic severe MR, an end-systolic diameter of less than 45 mm, and an ejection fraction (EF) of greater than 60%, peak systolic tissue Doppler velocities at the lateral mitral annulus accurately predicted postoperative reductions in EF and therefore LV dysfunction. Specifically, a myocardial systolic wave velocity of not more than 10 cm/s appears to be predictive of a postoperative EF reduction of at least 10% [18].

Of interest is the growing usefulness of RT3DE, which permits full or partial volume image acquisition in multiple planes [19]. Real-time assessment of mitral annular geometry has enhanced our understanding of the pathophysiology of MR [20]. In our opinion, in the near future, most of the prognostic M-mode echocardiography and 2DE parameters previously reported will be even more accurate at risk-stratifying patients by using results of 3DE (owing to its superior reproducibility and fewer restrictions on heart size and shape). This technique is useful in quantifying mitral regurgitant flows, usually underestimated with the proximal isovelocity surface area method using 2DE [21]. In fact, while 2DE measurement of vena contracta width is a commonly accepted method of assessing MR severity, RT3DE permits more accurate assessment of this dimension. RT3DE measures nonspehrical regurgitant orifices by direct planimetry without using calculations based on inaccurate assumptions [22].

An important complication of MV disease [both MR and mitral stenosis (MS)] is pulmonary hypertension (PH) with subsequent right ventricular dysfunction and failure [23]. A preoperative pulmonary artery systolic pressure (PAP) of at least 50 mm Hg is an independent predictor of postoperative LV dysfunction as compared with patients with a PAP of not more than 30 mm Hg and a similar preoperative LVEF. While current guidelines indicate surgical intervention at a PAP of greater than 50 mm Hg, these findings may suggest the need for a more aggressive surgical approach to patients with MR and PH [23]. An important avoidable complication of mitral valve replacement (MVR) is PPM, which is strongly associated with PH after surgery. An indexed mitral effective orifice area (EOA) of less than 1.2 cm2/m2 is associated with a postoperative PAP of greater than 40 mm Hg [24]. With the onset of MS, left atrial pressure increases. As severity of the disease progresses, increases in PAP occur with subsequent RV dysfunction, tricuspid annular dilation (TAD), and tricuspid regurgitation (TR) [24]. Moderate to severe postoperative TR in MVR is a strong predictor of all-cause mortality [25]. TR also indicates poor prognosis in patients undergoing balloon mitral valvotomy [24]. Reduction of PAP as a result of MVR may not prevent persistent TAD postoperatively. Right ventricular dysfunction, once symptomatic, may already be irreversible. Echocardiographic assessment of the tricuspid valve is therefore a necessary diagnostic component in patients with MS. A 2DE finding of a TAD of greater than 3.5 cm (regardless of severity of TR) indicates the consideration for tricuspid annuloplasty to be performed concomitantly with MV surgery [24].

Pulmonic regurgitation

One important right-sided valve lesion to mention, as its incidence is increasing, is pulmonic regurgitation (PR) [26]. There are now more adults living in the US with congenital heart disease than children and most of the former arrive there via successful pediatric surgical interventions. Progressive PR is common in these adolescents and adults. Initially, the RV responds well, but variably, to severe PR. However, at some point, the RV will fail. This ‘point of no return’ seems to be an RV ESVI of greater than 150 mL/m2 [23].

Implications for clinical practice

This review confirms the importance of quantifiable information gathered via M-mode, 2D, 3D, and Doppler echocardiography in predicting patient outcomes. The updated parameters are easily obtained and are more accurate at risk-stratifying patients than previously used qualitative values [27]. These measurements are crucial for determining prognosis and utilization of surgical and percutaneous interventions in patients with valvular heart disease.

In the setting of AS, prognostic parameters that integrate the valvular, ventricular, and vascular components of the disease may allow more optimal timing of intervention [28]. The fact that the tissue Doppler echocardiography A′ is a better predictor of mortality than AVA is consistent with the acknowledged importance of compensatory left atrial function in the natural history of AS [5]. Aortic, and to a lesser extent mitral, PPM may be avoided by calculating the projected indexed EOA of the considered prosthesis prior to intervention. The indexed EOA is calculated by dividing the EOA of the prosthesis by the patient’s BSA and may be used to select prostheses as well as to quantify the severity of PPM according to the guidelines in Table 1 [29]. For patients with AR, a number of prognostic echo values that should be considered as criteria for valve surgery are provided [8].

Table 1.
Echocardiographic prognostic variables listed by valve disease

One of the major reasons echocardiography is such a frequently employed diagnostic tool is that it allows serial exams to be performed safely. By knowing the quantitative dimensions that provide pertinent prognostic information, the physician may choose to alter the interval for subsequent evaluation. For example, an asymptomatic patient normally followed annually with moderate to severe AR and a recently determined LV diastolic index of 24 mm/m2 would warrant very close follow-up (as well as quantitation of AR severity). This patient, on the edge of LV failure, should probably not wait another year prior to evaluation. On the contrary, if the LVDd is only 18 mm/m2, then waiting a year remains reasonable. Furthermore, increases in MR by greater than 1 MR grade on serial echocardiography are associated with left atrial and ventricular dilatation and an overall poor prognosis [14].

Early surgery is associated with improved clinical outcome in patients with severe asymptomatic MR [30]. This fact is valid only when the regurgitation is carefully quantitated and confirmed to be severe. This practice of operating on asymptomatic MR should not be recommended based upon the visual qualitative assessment of MR severity. Color Doppler is notoriously poor at identifying the population of asymptomatic patients who would improve with valve surgery. In asymptomatic patients with organic MR, annualized rate of change of the effective regurgitant orifice area is strongly associated with progression of symptoms and LV dysfunction [31].

Recent advances in the 3D matrix-array TEE technology have improved the assessment of native MV components, and this technology has become a valuable tool in the assessment of prosthetic valves, particularly mitral prosthetic valves [32]. This new tool not only provides prognostic assessment of both native and prosthetic MVs before surgery but also serves as a superior means of postoperative evaluation.

Three-dimensional echocardiography, either transthoracic or TEE, is useful in planning for MV repair and will certainly play a crucial role in the percutaneous treatment of MV disease [20]. Moreover, given the improved quantitation of LV and RV volumes, the role of 3DE in expanding our knowledge of patient outcomes will continue to improve. Since the major consequence of valvular heart disease is not the valve per se but the myocardium, which remains in jeopardy of failing if the valve disease is left unrepaired too long, careful measurement of serial myocardial volumes will be crucial. This fact has been recently highlighted with pulmonary regurgitation. An aggressive surgical intervention policy that intervenes with pulmonary valve replacement prior to a right ventricular end-systolic volume of greater than 150 mL/m2 will result in a normalization of volumes as well as improvement in both biventricular systolic function and exercise capacity [33]. Through adherence to this quantitative prognostic concept, it is hoped that RV dysfunction will be less common and in time patient outcomes for this valve disease will show improvement.

Valvular heart disease is a well-known cause of left ventricular dysfunction and heart failure symptoms. Measurements obtained via TDI can be used in the classification and prognosis of patients with LV dysfunction [34]. The E/E′ ratio predicts functional class in patients with heart failure (class IV = 12.9 ± 2.8 versus class III = 8.3 ± 1.7) [34]. This simple measure, routinely performed during all echo exams, holds true for patients with MR, in whom the E/E′ ratio predicts all-cause mortality and worsening heart failure [17]. This value should be used clinically as a guide to increase afterload-reducing agents or diuretic therapy or both if the E/E′ ratio exceeds 15-20.

Conclusions

Given our greater understanding of the prognostic implications of these readily obtained echocardiographic variables, this diagnostic tool will remain the primary workhorse for the evaluation of patients with valvular heart disease. Use of these variables may indicate the need for early surgery for some patients with valvular heart disease. Echo should be considered at least partly responsible for the significant reductions in morbidity and mortality that have recently been demonstrated in patients with valvular heart disease. Physicians with expertise in this field should expand their evaluation beyond the basic structural and functional interpretation to a more clinically valuable prognostic report, taking the findings summarized in Table 1 into consideration.

Acknowledgments

This work was supported in part by National Institutes of Health grant #T35HL07479, a Short-Term Institutional Research Training Grant. VLS holds the Allan C Hudson and Helen Lovaas endowed chair for cardiac imaging at the Sarver Heart Center.

Abbreviations

2D
two-dimensional
2DE
two-dimensional echocardiography
3D
three-dimensional
3DE
three-dimensional echocardiography
A′
late (atrial) diastolic mitral annular velocity
AR
aortic regurgitation
AS
aortic stenosis
AV
aortic valve
AVA
aortic valve area
AVR
aortic valve replacement
BNP
B-type natriuretic peptide
BSA
body surface area
CR
contractile reserve
E/E′
early mitral filling velocity/early diastolic mitral annular velocity
EF
ejection fraction
EOA
effective orifice area
ERO
effective regurgitant orifice
ESVI
end-systolic volume index
LV
left ventricle
LVDd
left ventricular end-diastolic diameter
LVEF
left ventricular ejection fraction
MR
mitral regurgitation
MS
mitral stenosis
MV
mitral valve
MVR
mitral valve replacement
PAP
pulmonary artery systolic pressure
PH
pulmonary hypertension
PPM
prosthesis patient mismatch
PR
pulmonic regurgitation
RT3DE
real-time three-dimensional echocardiography
RV
right ventricle
TAD
tricuspid annular dilation
TDI
tissue Doppler imaging
TEE
transesophageal echocardiography
TR
tricuspid regurgitation

Notes

The electronic version of this article is the complete one and can be found at: http://F1000.com/Reports/Medicine/content/1/98

Notes

Competing interests

The authors declare that they have no competing interests.

References

1. Baumgartner H, Hung J, Bermejo J, Chambers JB, Evangelista A, Griffin BP, Iung B, Otto CM, Pellikka PA, Quiñones M; EAE/ASE Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. Eur J Echocardiogr. 2009;10:1–25. doi: 10.1093/ejechocard/jen303. [PubMed] [Cross Ref]
2. Ding WH, Lam YY, Kaya MG, Li W, Chung R, Pepper JR, Henein MY. Echocardiographic predictors of left ventricular functional recovery following valve replacement surgery for severe aortic stenosis. Int J Cardiol. 2008;128:178–84. doi: 10.1016/j.ijcard.2007.05.025. [PubMed] [Cross Ref]
3. Otto CM, Burwash IG, Legget ME, Munt BI, Fujioka M, Healy NL, Kraft CD, Miyake-Hull CY, Schwaegler RG. Prospective study of asymptomatic valvular aortic stenosis. Clinical, echocardiographic, and exercise predictors of outcome. Circulation. 1997;95:2262–70. [PubMed]
4. Ahmed S, Honos GN, Walling AD, Michel CM, Sebag IA, Rudski LG, Therrien J. Clinical outcome and echocardiographic predictors of aortic valve replacement in patients with bicuspid aortic valve. J Am Soc Echocardiogr. 2007;20:998–1003. doi: 10.1016/j.echo.2007.01.003. [PubMed] [Cross Ref]
5. Monin JL, Quéré JP, Monchi M, Petit H, Baleynaud S, Chauvel C, Pop C, Ohlmann P, Lelguen C, Dehant P, Tribouilloy C, Guéret P. Low-gradient aortic stenosis: operative risk stratification and predictors for long-term outcome: a multicenter study using dobutmine stress hemodynamics. Circulation. 2003;108:319–24. doi: 10.1161/01.CIR.0000079171.43055.46. [PubMed] [Cross Ref]
6. Mohty D, Dumesnil JG, Echahidi N, Mathieu P, Dagenais F, Voisine P, Pibarot P. Impact of prosthesis-patient mismatch on long-term survival after aortic valve replacement: influence of age, obesity, and left ventricular dysfunction. J Am Coll Cardiol. 2009;53:39–47. doi: 10.1016/j.jacc.2008.09.022. [PubMed] [Cross Ref] F1000 Factor 3.0 Recommended
Evaluated by John Paraskos 30 Jan 2009
7. Jilaihawi H, Chin D, Vasa-Nicotera M, Jeilan M, Spyt T, Ng GA, Bence J, Logtens E, Kovac J. Predictors for permanent pacemaker requirement after transcatheter aortic valve implantation with the CoreValve bioprosthesis. Am Heart J. 2009;157:860–6. doi: 10.1016/j.ahj.2009.02.016. [PubMed] [Cross Ref]
8. American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Society of Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interventions; Society of Thoracic Surgeons. Bonow RO, Carabello BA, Kanu C, de Leon AC, Jr, Faxon DP, Freed MD, Gaasch WH, Lytle BW, Nishimura RA, O'Gara PT, O'Rourke RA, Otto CM, Shah PM, Shanewise JS, Smith SC, Jr, Jacobs AK, Adams CD, Anderson JL, Antman EM, Faxon DP, Fuster V, Halperin JL, Hiratzka LF, Hunt SA, Lytle BW, Nishimura R, Page RL, Riegel B. ACC/AHA 2006 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 (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. Circulation. 2006;114:e84–231. [PubMed]
9. Sambola A, Tornos P, Ferreira-Gonzalez I, Evangelista A. Prognostic value of preoperative indexed end-systolic left ventricle diameter in the outcome after surgery in patients with chronic aortic regurgitation. Am Heart J. 2008;155:1114–20. doi: 10.1016/j.ahj.2007.12.025. [PubMed] [Cross Ref]
10. Detaint D, Messika-Zeitoun D, Maalouf J, Tribouilloy C, Mahoney DW, Tajik AJ, Enriquez-Sarano M. Quantitative echocardiographic determinants of clinical outcome in asymptomatic patients with aortic regurgitation: a prospective study. JACC Cardiovasc Imaging. 2008;1:1–11. doi: 10.1016/j.jcmg.2007.10.008. [PubMed] [Cross Ref]Changes Clinical Practice
F1000 Factor 6.0 Must Read
Evaluated by Vincent Sorrell 01-05-2008
11. Agricola E, Meris A, Oppizzi M, Bombardini T, Pisani M, Fragasso G, Margonato A. Rest and stress echocardiographic predictors of prognosis in patients with left ventricular dysfunction and functional mitral regurgitation. Int J Cardiol. 2008;124:247–9. doi: 10.1016/j.ijcard.2006.11.234. [PubMed] [Cross Ref]
12. Avierinos JF, Detaint D, Messika-Zeitoun D, Mohty D, Enriquez-Sarano M. Risk, determinants, and outcome implications of progression of mitral regurgitation after diagnosis of mitral valve prolapse in a single community. Am J Cardiol. 2008;101:662–7. doi: 10.1016/j.amjcard.2007.10.029. [PubMed] [Cross Ref] F1000 Factor 3.0 Recommended
Evaluated by John Paraskos 02 Apr 2008
13. Ling LH, Enriquez-Sarano M, Seward JB, Tajik AJ, Schaff HV, Bailey KR, Frye RL. Clinical outcome of mitral regurgitation due to flail leaflet. N Engl J Med. 1996;335:1417–23. doi: 10.1056/NEJM199611073351902. [PubMed] [Cross Ref]
14. Grigioni F, Tribouilloy C, Avierinos JF, Barbieri A, Ferlito M, Trojette F, Tafanelli L, Branzi A, Szymanski C, Habib G, Modena MG, Enriquez-Sarano M, MIDA Investigators Outcomes in mitral regurgitation due to flail leaflets a multicenter European study. JACC Cardiovasc Imaging. 2008;1:133–41. doi: 10.1016/j.jcmg.2007.12.005. [PubMed] [Cross Ref]
15. Ryan LP, Jackson BM, Eperjesi TJ, Plappert TJ, St John-Sutton M, Gorman RC, Gorman JH., 3rd A methodology for assessing human mitral leaflet curvature using real-time 3-dimensional echocardiography. J Thorac Cardiovasc Surg. 2008;136:726–34. doi: 10.1016/j.jtcvs.2008.02.073. [PubMed] [Cross Ref]
16. Yamano T, Gillinov AM, Wada N, Matsumura Y, Toyono M, Thomas JD, Shiota T. Doppler-derived preoperative mitral regurgitation volume predicts postoperative left ventricular dysfunction after mitral valve repair. Am Heart J. 2009;157:875–82. doi: 10.1016/j.ahj.2009.03.001. [PubMed] [Cross Ref]
17. Bruch C, Klem I, Breithardt G, Wichter T, Gradaus R. Diagnostic usefulness and prognostic implications of the mitral E/E′ ratio in patients with heart failure and severe secondary mitral regurgitation. Am J Cardiol. 2007;100:860–5. doi: 10.1016/j.amjcard.2007.03.108. [PubMed] [Cross Ref]
18. Agricola E, Galderisi M, Oppizzi M, Schinkel AF, Maisano F, De Bonis M, Margonato A, Maseri A, Alfieri O. Pulsed tissue Doppler imaging detects early myocardial dysfunction in asymptomatic patients with severe mitral regurgitation. Heart. 2004;90:406–10. doi: 10.1136/hrt.2002.009621. [PMC free article] [PubMed] [Cross Ref]
19. Weyman AE. Future directions in echocardiography. Rev Cardiovasc Med. 2009;10:4–13. [PubMed]
20. Solis J, Sitges M, Levine RA, Hung J. Three-dimensional echocardiography. New possibilities in mitral valve assessment. Rev Esp Cardiol. 2009;62:188–98. doi: 10.1016/S1885-5857(09)71537-3. [PMC free article] [PubMed] [Cross Ref]
21. Matsumura Y, Fukuda S, Tran H, Greenberg NL, Agler DA, Wada N, Toyono M, Thomas JD, Shiota T. Geometry of the proximal isovelocity surface area in mitral regurgitation by 3-dimensional color Doppler echocardiography: difference between functional mitral regurgitation and prolapse regurgitation. Am Heart J. 2008;155:231–8. doi: 10.1016/j.ahj.2007.09.002. [PubMed] [Cross Ref]
22. Kahlert P, Plicht B, Schenk IM, Janosi RA, Erbel R, Buck T. Direct assessment of size and shape of noncircular vena contracta area in functional versus organic mitral regurgitation using real-time three-dimensional echocardiography. J Am Soc Echocardiogr. 2008;21:912–21. doi: 10.1016/j.echo.2008.02.003. [PubMed] [Cross Ref] F1000 Factor 3.0 Recommended
Evaluated by Vincent Sorrell 28 Oct 2008
23. Yang H, Davidson WR, Jr, Chambers CE, Pae WE, Sun B, Campbell DB, Pu M. Preoperative pulmonary hypertension is associated with postoperative left ventricular dysfunction in chronic organic mitral regurgitation: an echocardiographic and hemodynamic study. J Am Soc Echocardiogr. 2006;19:1051–5. doi: 10.1016/j.echo.2006.03.016. [PubMed] [Cross Ref]
24. Shiran A, Sagie A. Tricuspid regurgitation in mitral valve disease incidence, prognostic implications, mechanism, and management. J Am Coll Cardiol. 2009;53:401–8. doi: 10.1016/j.jacc.2008.09.048. [PubMed] [Cross Ref] F1000 Factor 3.0 Recommended
Evaluated by John Paraskos 04 Mar 2009
25. Ruel M, Rubens FD, Masters RG, Pipe AL, Bédard P, Mesana TG. Late incidence and predictors of persistent or recurrent heart failure in patients with mitral prosthetic valves. J Thorac Cardiovasc Surg. 2004;128:278–83. doi: 10.1016/j.jtcvs.2003.11.048. [PubMed] [Cross Ref]
26. Sorrell VL, Altbach MI, Kudithipudi V, Squire SW, Goldberg SJ, Klewer SE. Cardiac MRI is an important complementary tool to Doppler echocardiography in the management of patients with pulmonary regurgitation. Echocardiography. 2007;24:316–28. doi: 10.1111/j.1540-8175.2006.00395.x. [PubMed] [Cross Ref]
27. Carabello BA. Cardiologists: do we have the right to call ourselves physiologists? JACC Cardiovasc Imaging. 2008;1:12–4. doi: 10.1016/j.jcmg.2007.10.007. [PubMed] [Cross Ref]
28. Thanassoulis G, Yip JW, Filion K, Jamorski M, Webb G, Siu SC, Therrien J. Retrospective study to identify predictors of the presence and rapid progression of aortic dilatation in patients with bicuspid aortic valves. Nat Clin Pract Cardiovasc Med. 2008;5:821–8. doi: 10.1038/ncpcardio1369. [PubMed] [Cross Ref]
29. Pibarot P, Dumesnil JG. Prosthetic heart valves: selection of the optimal prosthesis and long-term management. Circulation. 2009;119:1034–48. doi: 10.1161/CIRCULATIONAHA.108.778886. [PubMed] [Cross Ref]
30. Kang DH, Kim JH, Rim JH, Kim MJ, Yun SC, Song JM, Song H, Choi KJ, Song JK, Lee JW. Comparison of early surgery versus conventional treatment in asymptomatic severe mitral regurgitation. Circulation. 2009;119:797–804. doi: 10.1161/CIRCULATIONAHA.108.802314. [PubMed] [Cross Ref] F1000 Factor 6.7 Must Read
Evaluated by John Paraskos 04 Mar 2009, John Augoustides 11 Mar 2009, Bernard Prendergast 02 Apr 2009, Bernard Iung 23 Apr 2009
31. Krauss J, Pizarro R, Oberti PF, Falconi M, Cagide A. Prognostic implication of valvular lesion and left ventricular size in asymptomatic patients with chronic organic mitral regurgitation and normal left ventricular performance. Am Heart J. 2006;152:1004.e1–8. [PubMed]
32. Sugeng L, Shernan SK, Weinert L, Shook D, Raman J, Jeevanandam V, DuPont F, Fox J, Mor-Avi V, Lang RM. Real-time three-dimensional transesophageal echocardiography in valve disease: comparison with surgical findings and evaluation of prosthetic valves. J Am Soc Echocardiogr. 2008;21:1347–54. doi: 10.1016/j.echo.2008.09.006. [PubMed] [Cross Ref]
33. Frigiola A, Tsang V, Bull C, Coats L, Khambadkone S, Derrick G, Mist B, Walker F, van Doorn C, Bonhoeffer P, Taylor AM. Biventricular response after pulmonary valve replacement for right ventricular outflow tract dysfunction: is age a predictor of outcome? Circulation. 2008;118(14):S182–90. doi: 10.1161/CIRCULATIONAHA.107.756825. [PubMed] [Cross Ref] F1000 Factor 3.0 Recommended
Evaluated by Willem Helbing 09 Jan 2009
34. Hamdan A, Shapira Y, Bengal T, Mansur M, Vaturi M, Sulkes J, Battler A, Sagie A. Tissue Doppler imaging in patients with advanced heart failure: relation to functional class and prognosis. J Heart Lung Transplant. 2006;25:214–8. doi: 10.1016/j.healun.2005.09.002. [PubMed] [Cross Ref]
35. Poh KK, Chan MY, Yang H, Yong QW, Chan YH, Ling LH. Prognostication of valvular aortic stenosis using tissue Doppler echocardiography: underappreciated importance of late diastolic mitral annular velocity. J Am Soc Echocardiogr. 2008;21:475–81. doi: 10.1016/j.echo.2007.08.031. [PubMed] [Cross Ref]
36. Rifaie O, Esmat I, Abdel-Rahman M, Nammas W. Can a novel echocardiographic score better predict outcome after percutaneous balloon mitral valvuloplasty? Echocardiography. 2009;26:119–27. doi: 10.1111/j.1540-8175.2008.00774.x. [PubMed] [Cross Ref]
37. Li M, Dumesnil JG, Mathieu P, Pibarot P. Impact of valve prosthesis-patient mismatch on pulmonary arterial pressure after mitral valve replacement. J Am Coll Cardiol. 2005;45:1034–40. doi: 10.1016/j.jacc.2004.10.073. [PubMed] [Cross Ref]

Articles from F1000 Medicine Reports are provided here courtesy of Faculty of 1000 Ltd