Aortic regurgitation surgery indications: Difference between revisions

Jump to navigation Jump to search
No edit summary
(No difference)

Revision as of 15:35, 6 January 2015

Aortic Insufficiency Surgery

Home

Overview

Indications

Treatment

Preoperative Evaluation

Valve selection

Procedure

Recovery

Outcomes & Prognosis

Complications

Videos

Aortic regurgitation surgery indications On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Aortic regurgitation surgery indications

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Aortic regurgitation surgery indications

CDC on Aortic regurgitation surgery indications

Aortic regurgitation surgery indications in the news

Blogs on Aortic regurgitation surgery indications

Directions to Hospitals Performing Aortic insufficiency Surgery

Risk calculators and risk factors for Aortic regurgitation surgery indications

For the WikiPatient page for this topic, click here; For the main page of AR, click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Mohammed A. Sbeih, M.D.[2]; Rim Halaby, M.D. [3]

Overview

Severe acute AR requires emergency surgery if there are no absolute contraindications to surgery. The surgery should be performed as early as possible without a delay, particularly if hypotension, decreased perfusion, or pulmonary edema are present. Aortic valve replacement is indicated in patients with severe AR who are either symptomatic or those who have a left ventricular end-diastolic diameter >55 mm or 25 mm/m2 or an left ventricular ejection fraction <55%.

Indications for Surgery for Acute Aortic Regurgitation

Timing of Emergency Surgery

Acute severe AR may cause death due to pulmonary edema, ventricular arrhythmias, electromechanical dissociation, or circulatory collapse. Individuals with bacteremia with aortic valve endocarditis should not wait for treatment with antibiotics to take effect, especially if there is hypotension, pulmonary edema, or low cardiac output given the high mortality associated with the acute AR.

Shown below is an algorithm for the treatment of acute AR.[1]

Abbreviations: AVR: Aortic valve replacement; ACE: Angiotensin converting enzyme; ARB: Angiotensin receptor blocker; CCB: Calcium channel blocker; LVEF: Left ventricle ejection fraction; TTE: Transthoracic echocardiography

 
 
 
 
What is the cause of acute AR?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Infective endocarditis
 
Aortic dissection
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Does the patient have AR related heart failure symptoms?
 
❑ Schedule for an emergent surgery[2]
❑ Administer beta blockers with caution (beta blockers inhibit compensatory tachycardia)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Schedule for early aortic valve replacement (Class I, level of evidence B)[3]
 
❑ Administer antibiotics[3]
❑ Follow up the patient
 
 
 

Type of Surgery

Replacement with an aortic valve homograft should be performed if feasible. The surgical approach depends upon the cause of AR. Aortic valve replacement or repair may be needed in cases of valvular structural abnormalities and aortic root repair/replacement may be needed in cases of aortic dissection.

Preoperative Medical Therapy

Patients may be temporarily managed before surgery with vasodilators such as nitroprusside and possibly inotropic agents such as dopamine or dobutamine to improve stroke volume and reduce left ventricular end-diastolic pressure.[4] Intra-aortic balloon pump is contraindicated as this would worsen aortic regurgitation by increasing afterload.

Mild Acute AR in the Setting of Aortic Dissection

In mild AR secondary to aortic dissection, the aortic valve can be repaired/replaced at the time of surgery for aortic dissection.

Indications for Surgery for Chronic Aortic Regurgitation

Shown below is an algorithm depicting the indications for aortic valve replacement (AVR) in chronic aortic regurgitation. Patients that fulfill the indications for AVR but have existing comorbidities that do not permit AVR should be treated for hypertension if the blood pressure is more than 140 mmHg. Patients with stage A AR do not require any treatment.[1][5]

Abbreviations: LVEF: left ventricular ejection fraction; LVEDD: left ventricular end diastolic diameter; LVESV: left ventricular end systolic diameter

 
 
 
 
 
 
 
 
 
 
 
 
 
 
What is the severity of the aortic regurgitation?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Severe regurgitation

❑ Vena contracta >0.6 cm
❑ Doppler jet width ≥ 65% of LVOT
❑ Regurgitant volume ≥60 mL/beat
❑ Regurgitant fraction ≥50%
❑ Effective regurgitant orifice ≥ 0.30 cm²
❑ Holodiastolic flow reversal in the proximal abdominal aorta
Left ventricle dilatation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Progressive regurgitation (Stage B)

❑ Vena contracta <0.6 cm
❑ Regurgitant volume <60 mL/beat
❑ Regurgitant fraction <50%
❑ Effective regurgitant orifice <0.30 cm²
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Is the patient symptomatic?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Is the patient undergoing
another surgery?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
(Stage D)
 
 
 
 
 
 
 
 
 
No
(Stage C)
 
 
 
 
 
 
 
 
 
No
 
Yes
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ LVEF<50%
(Stage C2)
 
❑ The patient is undergoing another surgery
 
LVEF ≥ 50%
AND
❑ LVESD > 50mm
(Stage C2)
 
LVEF ≥ 50%
AND
❑ LVEDD > 65mm
AND
❑ Low surgical risk
 
LVEF ≥ 50%
AND
❑ LVESD ≤ 50mm
AND
❑ LVEDD ≤ 65mm
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
AVR (Class I)
 
AVR (Class I)
 
AVR (Class I)
 
AVR (Class IIa)
 
AVR (Class IIb)
 
 
 
 
 
 
 
 
 
 
 
AVR (Class IIa)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Perform a periodic echocardiogram every 6 - 12 months (Class I, Level of Evidence C)
❑ Control hypertension preferably with
❑ Dihydropyridine CCB, or
ACE inhibitors or ARBs (Class I; Level of Evidence: B)
 

❑ Perform a periodic echocardiogram (Class I; Level of Evidence:B)

❑ Every 3 -5 years for mild regurgitation
❑ Every 1 - 2 years for moderate regurgitation

❑ Control hypertension preferably with

❑ Dihydropyridine CCB, or
ACE inhibitors or ARBs (Class I; Level of Evidence: B)
  • Aortic valve replacement improves symptoms in symptomatic patients with severe AR.
  • In some studies, the left ventricular function (ejection fraction) also improved following AVR[6] [7].
  • In severe AR, new onset of mild symptoms are also candidates for AVR. Surgery should not be delayed until the development of advanced symptoms as this may result in irreversible left ventricular dysfunction [8] [9].
  • Patients who are symptomatic with NYHA Class IV heart fialure have poor outcomes following AVR with less likelihood of an improvement in left ventricular systolic function [10] [11] [12] [13]. Following AVR, ventricular loading conditions may be improved and this may improve the subsequent management of left ventricular dysfunction[14].
  • Symptomatic patients even with mild to moderate left ventricular systolic dysfunction (ejection fraction 25%- 50%) should also undergo AVR.
  • The AHA/ACC guidelines recommends that patients with NYHA Class II and III symptoms should undergo valve replacement if [4]:
  1. The symptoms and evidence of left ventricular dysfunction are of recent onset
  2. Intensive short-term therapy with vasodilators and diuretics results in symptomatic improvement
  3. Intravenous positive inotropic agents result in substantial improvement in hemodynamics or systolic function.
  • Aortic valve replacement/repair is not recommended in a truly asymptomatic patient with normal left ventricular function (left ventricular ejection fraction ≥50%) who does not have severe left ventricular dilatation because this would expose the patient to perioperative mortality risk of 4% against less than 0.2% mortality risk without surgery and other long-term complications of a prosthetic heart valve[15]. In such patients 2006 AHA/ACC guidelines recommends [4]:
  • Patients with mild chronic AR with normal left ventricular ejection fraction should undergo clinical evaluation yearly and echocardiography every two to three years.
  • Patients with severe chronic AR with normal left ventricular ejection fraction should be followed up based on ventricular dimensions:
  1. Patients with end-systolic ventricular dimension <45 mm and end-diastolic ventricular dimension <60 mm should undergo clinical evaluation every 6 to 12 months and echocardiography every 12 months. However, if the patient is not stable or if this is the initial study, the patient should be re-evaluated and echocardiography performed in 3 months.
  2. Patients with end-systolic ventricular dimensions of 45-50 mm and end-diastolic ventricular dimensions of 60-70 mm should undergo clinical evaluation every 6 months and echocardiography every 12 months. However, if the patient is not stable or this is the initial study, then the patient should be re-evaluated and echocardiography performed in 3 months.
  3. Patients with end-systolic ventricular dimension 50-55 mm and end-diastolic ventricular dimension 70-75 mm with normal hemodynamic response to exercise should undergo clinical evaluation every 6months and echocardiography every 6 months. However, if the patient is not stable or this is the initial study, then the patient should be re-evaluated and echocardiography performed in 3 months.
  • When interpreting the cutpoints of left ventricular dimensions, the body size of the patients should also be taken into consideration. Women or patients with small body size may not achieve ventricular dimensions mentioned above as these dimensions were established in men [16] [17]. On the other hand, body surface area measures are considered in the assessment of left ventricular dimension, tend to mask the diagnosis of left ventricular enlargement, especially in patients who are overweight[18]. Therefore patient's height and gender should be considered during interpretation of ventricular dimensions. [19]
Indications for surgery for chronic severe AR[20]
Symptoms Ejection fraction Other information
NYHA class III - IV ≥ 50 %
NYHA class II ≥ 50 % Progression of symptoms or worsening parameters on echocardiography
CHA class ≥ II angina ≥ 50 %
Regardless of symptoms 25 - 49 %
Cardiac surgery for other cause (ie: CAD, other valvular disease, ascending aortic aneurysm)

2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Diseases (DO NOT EDIT)[21]

Timing of Intervention

Class I
"1. AVR is indicated for symptomatic patients with severe AR regardless of LV systolic function (stage D). (Level of Evidence: B)"
"2. AVR is indicated for asymptomatic patients with chronic severe AR and LV systolic dysfunction (LVEF <50%) at rest (stage C2) if no other cause for systolic dysfunction is identified. (Level of Evidence: B)"
"3. AVR is indicated for patients with severe AR (stage C or D) while undergoing cardiac surgery for other indications. (Level of Evidence: C)"
Class IIa
"1. AVR is reasonable for asymptomatic patients with severe AR with normal LV systolic function (LVEF ≥50%) but with severe LV dilation (LVESD >50 mm or indexed LVESD >25 mm/m2) (stage C2). (Level of Evidence: B)"
"2. AVR is reasonable in patients with moderate AR (stage B) while undergoing surgery on the ascending aorta, CABG, or mitral valve surgery. (Level of Evidence: C)"
Class IIb
"1. AVR may be considered for asymptomatic patients with severe AR and normal LV systolic function at rest (LVEF ≥50%, stage C1) but with progressive severe LV dilatation (LV end-diastolic dimension >65 mm) if surgical risk is low. (Level of Evidence: B)"

2008 ACC/AHA Guidelines for the Management of Patients with Valvular Heart Disease (DO NOT EDIT) [4]

Aortic Valve Replacement Indications (DO NOT EDIT) [4]

Class I
"1. AVR is indicated for symptomatic patients with severe AR irrespective of LV systolic function. (Level of Evidence: B)"
"2. AVR is indicated for asymptomatic patients with chronic severe AR and left ventricular systolic dysfunction (ejection fraction 50% or less) at rest. (Level of Evidence: B)"
"3. AVR is indicated for patients with chronic severe AR while undergoing coronary artery bypass graft(CABG) or surgery on the aorta or other heart valves. (Level of Evidence: C)"
Class III
"1. AVR is not indicated for asymptomatic patients with mild, moderate, or severe AR and normal left ventricular systolic function at rest (ejection fraction greater than 50%) when the degree of dilatation is not moderate or severe (end-diastolic dimension less than 70 mm, end-systolic dimension less than 50 mm)*. (Level of Evidence: B)
Class IIa
"1. AVR is reasonable for asymptomatic patients with severe AR with normal left ventricular systolic function (ejection fraction greater than 50%) but with severe left ventricular dilatation (end-diastolic dimension greater than 75 mm or end-systolic dimension greater than 55 mm)*. (Level of Evidence: B)"
Class IIb
"1. AVR may be considered in patients with moderate AR while undergoing surgery on the ascending aorta. (Level of Evidence: C)"
"2. AVR may be considered in patients with moderate AR while undergoing CABG. (Level of Evidence: C)"
"3. AVR may be considered for asymptomatic patients with severe AR and normal left ventricular systolic function at rest (ejection fraction greater than 50%) when the degree of left ventricular dilatation exceeds an end-diastolic dimension of 70 mm or end-systolic dimension of 50 mm, when there is evidence of progressive left ventricular dilatation, declining exercise tolerance, or abnormal hemodynamic responses to exercise.* (Level of Evidence: C)"
* Consider lower threshold values for patients of small stature of either gender.

Aortic Valve Replacement Indications in Adolescents (DO NOT EDIT) [4]

Class I
"1. An adolescent or young adult with chronic severe AR with onset of symptoms of angina, syncope, or dyspnea on exertion should receive aortic valve repair or replacement. (Level of Evidence: C)"
"2. Asymptomatic adolescent or young adult patients with chronic severe AR with LV systolic dysfunction (ejection fraction less than 0.50) on serial studies 1 to 3 months apart should receive aortic valve repair or replacement. (Level of Evidence: C)"
"3. Asymptomatic adolescent or young adult patients with chronic severe AR with progressive LV enlargement (end-diastolic dimension greater than 4 standard deviations above normal) should receive aortic valve repair or replacement. (Level of Evidence: C)"
Class IIb
"1. An asymptomatic adolescent with chronic severe AR with moderate AS (peak LV–to–peak aortic gradient greater than 40 mm Hg at cardiac catheterization) may be considered for aortic valve repair or replacement. (Level of Evidence: C)"
"2. An asymptomatic adolescent with chronic severe AR with onset of ST depression or T-wave inversion over the left precordium on ECG at rest may be considered for aortic valve repair or replacement. (Level of Evidence: C)"

AHA/ACC 2014 Guideline for the Management of Patients With Valvular Heart Diseases

Class I
"1. AVR is indicated for symptomatic patients with severe AR regardless of LV systolic function (stage D) (Level of Evidence: B) "
"2. AVR is indicated for asymptomatic patients with chronic severe AR and LV systolic dysfunction (LVEF <50%) (stage C2) (Level of Evidence: B) "
"3. AVR is indicated for patients with severe AR (stage C or D) while undergoing cardiac surgery for other indications (Level of Evidence: C) "
Class IIa
"1. AVR is reasonable for asymptomatic patients with severe AR with normal LV systolic function (LVEF ≥50%) but with severe LV dilation (LVESD >50 mm, stage C2) (Level of Evidence: B)"
"2. AVR is reasonable in patients with moderate AR (stage B) who are undergoing other cardiac surgery (Level of Evidence: C) "
Class IIb
"1. AVR may be considered for asymptomatic patients with severe AR and normal LV systolic function (LVEF ≥50%, stage C1) but with progressive severe LV dilation (LVEDD >65 mm) if surgical risk is low (Level of Evidence: C) "

Sources

  • 2008 ACC/AHA Guidelines incorporated into the 2006 guidelines for the management of patients with valvular heart disease [4]

References

  1. 1.0 1.1 Nishimura, R. A.; Otto, C. M.; Bonow, R. O.; Carabello, B. A.; Erwin, J. P.; Guyton, R. A.; O'Gara, P. T.; Ruiz, C. E.; Skubas, N. J.; Sorajja, P.; Sundt, T. M.; Thomas, J. D. (2014). "2014 AHA/ACC Guideline 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". Circulation. doi:10.1161/CIR.0000000000000031. ISSN 0009-7322.
  2. "http://circ.ahajournals.org/content/121/13/e266.full". External link in |title= (help)
  3. 3.0 3.1 Baddour, LM.; Wilson, WR.; Bayer, AS.; Fowler, VG.; Bolger, AF.; Levison, ME.; Ferrieri, P.; Gerber, MA.; Tani, LY. (2005). "Infective endocarditis: diagnosis, antimicrobial therapy, and management of complications: a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, and the Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association: endorsed by the Infectious Diseases Society of America". Circulation. 111 (23): e394–434. doi:10.1161/CIRCULATIONAHA.105.165564. PMID 15956145. Unknown parameter |month= ignored (help)
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Bonow RO, Carabello BA, Chatterjee K, de Leon AC, Faxon DP, Freed MD, Gaasch WH, Lytle BW, Nishimura RA, O'Gara PT, O'Rourke RA, Otto CM, Shah PM, Shanewise JS (2008). "2008 Focused update incorporated into the 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): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons". Circulation. 118 (15): e523–661. doi:10.1161/CIRCULATIONAHA.108.190748. PMID 18820172. Retrieved 2011-04-07. Unknown parameter |month= ignored (help)
  5. Bonow, R. O.; Carabello, B. A.; Chatterjee, K.; de Leon, A. C.; Faxon, D. P.; Freed, M. D.; Gaasch, W. H.; Lytle, B. W.; Nishimura, R. A.; O'Gara, P. T.; O'Rourke, R. A.; Otto, C. M.; Shah, P. M.; Shanewise, J. S. (2008). "2008 Focused Update Incorporated Into the 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): Endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons". Circulation. 118 (15): e523–e661. doi:10.1161/CIRCULATIONAHA.108.190748. ISSN 0009-7322.
  6. Daniel WG, Hood WP, Siart A, Hausmann D, Nellessen U, Oelert H, Lichtlen PR (1985). "Chronic aortic regurgitation: reassessment of the prognostic value of preoperative left ventricular end-systolic dimension and fractional shortening". Circulation. 71 (4): 669–80. PMID 3156010. Retrieved 2011-03-27. Unknown parameter |month= ignored (help)
  7. Carabello BA, Usher BW, Hendrix GH, Assey ME, Crawford FA, Leman RB (1987). "Predictors of outcome for aortic valve replacement in patients with aortic regurgitation and left ventricular dysfunction: a change in the measuring stick". Journal of the American College of Cardiology. 10 (5): 991–7. PMID 3668112. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  8. Klodas E, Enriquez-Sarano M, Tajik AJ, Mullany CJ, Bailey KR, Seward JB (1997). "Optimizing timing of surgical correction in patients with severe aortic regurgitation: role of symptoms". Journal of the American College of Cardiology. 30 (3): 746–52. PMID 9283535. Retrieved 2011-03-27. Unknown parameter |month= ignored (help)
  9. Carabello BA (2004). "Is it ever too late to operate on the patient with valvular heart disease?". Journal of the American College of Cardiology. 44 (2): 376–83. doi:10.1016/j.jacc.2004.03.061. PMID 15261934. Retrieved 2011-03-27. Unknown parameter |month= ignored (help)
  10. Bonow RO, Dodd JT, Maron BJ, O'Gara PT, White GG, McIntosh CL, Clark RE, Epstein SE (1988). "Long-term serial changes in left ventricular function and reversal of ventricular dilatation after valve replacement for chronic aortic regurgitation". Circulation. 78 (5 Pt 1): 1108–20. PMID 2972417. Retrieved 2011-03-27. Unknown parameter |month= ignored (help)
  11. Greves J, Rahimtoola SH, McAnulty JH, DeMots H, Clark DG, Greenberg B, Starr A (1981). "Preoperative criteria predictive of late survival following valve replacement for severe aortic regurgitation". American Heart Journal. 101 (3): 300–8. PMID 6451163. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  12. Bonow RO, Picone AL, McIntosh CL, Jones M, Rosing DR, Maron BJ, Lakatos E, Clark RE, Epstein SE (1985). "Survival and functional results after valve replacement for aortic regurgitation from 1976 to 1983: impact of preoperative left ventricular function". Circulation. 72 (6): 1244–56. PMID 4064269. Retrieved 2011-03-27. Unknown parameter |month= ignored (help)
  13. Cunha CL, Giuliani ER, Fuster V, Seward JB, Brandenburg RO, McGoon DC (1980). "Preoperative M-mode echocardiography as a predictor of surgical results in chronic AR". The Journal of Thoracic and Cardiovascular Surgery. 79 (2): 256–65. PMID 7351849. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  14. Clark DG, McAnulty JH, Rahimtoola SH (1980). "Valve replacement in AR with left ventricular dysfunction". Circulation. 61 (2): 411–21. PMID 7351067. Retrieved 2011-03-28. Unknown parameter |month= ignored (help)
  15. Bekeredjian R, Grayburn PA (2005). "Valvular heart disease: aortic regurgitation". Circulation. 112 (1): 125–34. doi:10.1161/CIRCULATIONAHA.104.488825. PMID 15998697. Retrieved 2011-03-28. Unknown parameter |month= ignored (help)
  16. Stone PH, Clark RD, Goldschlager N, Selzer A, Cohn K (1984). "Determinants of prognosis of patients with aortic regurgitation who undergo aortic valve replacement". Journal of the American College of Cardiology. 3 (5): 1118–26. PMID 6707364. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  17. Klodas E, Enriquez-Sarano M, Tajik AJ, Mullany CJ, Bailey KR, Seward JB (1996). "Surgery for aortic regurgitation in women. Contrasting indications and outcomes compared with men". Circulation. 94 (10): 2472–8. PMID 8921790. Retrieved 2011-03-28. Unknown parameter |month= ignored (help)
  18. Mathew RK, Gaasch WH, Guilmette NE, Schick EC, Labib SB (2003). "Anthropometric normalization of left ventricular size in chronic mitral regurgitation". The American Journal of Cardiology. 91 (6): 762–4. PMID 12633821. Retrieved 2011-03-28. Unknown parameter |month= ignored (help)
  19. Vasan RS, Larson MG, Levy D, Evans JC, Benjamin EJ (1997). "Distribution and categorization of echocardiographic measurements in relation to reference limits: the Framingham Heart Study: formulation of a height- and sex-specific classification and its prospective validation". Circulation. 96 (6): 1863–73. PMID 9323074. Retrieved 2011-03-28. Unknown parameter |month= ignored (help)
  20. "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 (Committee on Management of Patients with Valvular Heart Disease)". J. Am. Coll. Cardiol. 32 (5): 1486–588. 1998. PMID 9809971.
  21. "2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary". Retrieved 4 March 2014.

Template:WH Template:WS