Mitral Valvular Disease
Sorin V. Pislaru
1. Which of the following echocardiographic findings are important in predicting the outcome of mitral balloon valvuloplasty?
A. Presence of significant valvular calcification.
B. Presence of significant valvular thickening.
C. Presence of significant subvalvular calcifications.
D. All of the above.
E. A and B.
1. Answer: E. The score used for predicting the outcome of mitral balloon valvuloplasty takes into account valve leaflet mobility, thickness, calcification, and subvalvular thickening. Each is given a score of 1-4; when the total score is 8 or less, the valve is considered amenable to balloon valvuloplasty. Subvalvular calcifications are not included in this score (answer C is false). The correct answer is E.
2. During routine assessment of a patient with known valvular disease, the sonographer measures a mitral inflow deceleration time of 758 ms. Which of the following is a reasonable estimate of the mitral valve area?
A. 1 cm2.
B. 0.3 cm2.
C. 3 cm2.
D. 1.5 cm2.
E. 2 cm2.
2. Answer: A. This question refers to mitral valve area calculation based on the pressure half-time. Commonly in the echocardiography board examination, the candidate is not presented with the actual pressure half-time measurement, but rather with a still image of a continuous wave Doppler signal or in this case with the measured deceleration time. The relationship between pressure half-time and deceleration time is constant:
Pressure half-time = 0.29 × deceleration time.
Furthermore, the mitral valve area is estimated according to the formula:
MVA = 220/pressure half-time.
Using the numbers provided, MVA is 220/(0.29 × 758 ms) = 1 cm2 (answer A).
3. Which of the following mitral stenosis patients is likely to benefit from mitral balloon valvuloplasty?
A. Asymptomatic 29-year-old woman with a mitral mean gradient of 9 mm Hg and resting TR velocity of 4 m/s.
B. A 49-year-old man complaining of dyspnea and a mitral pressure half-time of 110 ms.
C. A 62-year-old woman complaining of dyspnea and evidence of heavily calcified mitral commissures and a mitral valve mean gradient of 12 mm Hg.
D. An asymptomatic 35-year-old woman with a mitral valve mean gradient of 12 mm Hg and a loud apical systolic murmur.
3. Answer: A. This question addresses the indications and contraindications for mitral balloon valvuloplasty. Case A is consistent with moderate mitral stenosis. While asymptomatic, a TR velocity of 4 m/s is suggestive of a pulmonary artery systolic pressure in excess of 70 mm Hg; therefore, this patient has a clear indication for balloon valvuloplasty (correct answer). See Figure 17-9 on indications for intervention for mitral stenosis. In case B, the mitral valve area is estimated at 2 cm2 (220/pressure half-time), and therefore the etiology of dyspnea must be sought elsewhere. The mechanism of successful mitral valvuloplasty is commissural separation; presence of heavy calcification is associated with lower procedural success and higher incidence of significant mitral regurgitation (answer C is false). Presence of significant mitral regurgitation (suggested by clinical examination) is a contraindication for valvuloplasty (answer D is false).
4. A comprehensive echocardiogram is performed for assessment of mitral regurgitation. The mitral annulus measures 4 cm in diameter and the time velocity integral (TVI) of the Doppler signal obtained from the plane of the mitral valve is 10 cm. The LVOT diameter is 2 cm, with a TVI of 25 cm. The mitral regurgitant volume is:
A. 125 mL.
B. 47 mL.
C. 78.5 mL.
D. 30 mL.
E. The regurgitant volume cannot be calculated on the basis of presented data.
4. Answer: B. This question uses the continuity equation for estimating the mitral regurgitant volume (MRV). In the absence of significant aortic regurgitation, the net flow through the aortic valve must equal the net flow through the mitral valve:
Aortic flow = mitral forward flow – mitral regurgitant flow
Therefore, MRV can be estimated by the formula:
MRV = mitral forward flow – aortic stroke volume
MRV = (mitral valve area × mitral valve plane TVI) – (LVOT area × LVOT TVI)
MRV = 3.14 × (4/2)2 × 10 – 3.14 × (2/2)2 ×25 = 125.6 – 78.5 = 47 mL (answer B)
5. A cardiac surgeon calls you regarding an echocardiogram from an outside laboratory. He noticed significant mitral regurgitation by color Doppler and asks you to help with formal quantification of the degree of regurgitation. The study shows clips for mitral regurgitant PISA (aliasing velocity 40 cm/s, PISA radius 1 cm), but there is no continuous wave Doppler interrogation of the mitral regurgitant signal. You tell him that an exact measurement cannot be done without knowing the exact mitral regurgitant velocity and TVI; however, with some reasonable assumptions, you can say that:
A. Mitral regurgitation is severe because mitral effective regurgitant area is ˜0.50 cm2.
B. Mitral regurgitation is nearly severe because the effective regurgitant area is ˜0.38 cm2.
C. Mitral regurgitation is severe because the regurgitant volume is ˜95 mL.
D. Mitral regurgitation cannot be estimated on the basis of existing data.
5. Answer: A. There are several simplified calculations that are commonly used in PISA evaluation of mitral regurgitation. They are all based on some presumptions, but their simplicity makes them attractive for rapid calculations. Two simplified methods are commonly used for effective regurgitant orifice area (EROA) calculation. In the first one, the aliasing velocity is set at 40 cm/s. If the mitral regurgitant velocity is considered 500 cm/s (a reasonable assumption when systemic blood pressure is normal), calculation of the EROA is:
PISA surface × aliasing velocity = EROA × regurgitant velocity:
EROA = (2 × 3.14 × R2 × 40 cm/s)/500 cm/s = 251 × R2/500 = R2/2
Using this simplification, the EROA is 0.5 cm2 (correct answer A).
A second simplification for EROA is using an aliasing velocity of 30 cm/s and assuming again that the mitral regurgitant velocity is 500 cm/s. With these numbers
EROA = 2 × 3.14 × R2 × 30/500 = 0.38 × R2
So that if PISA radius is more than 1 cm, the EROA is more than 0.38 cm2; that is, the regurgitation is severe.
There is also a simplification for estimating the regurgitant volume (RV). This takes advantage of the observation that the ratio between mitral regurgitant TVI and velocity is relatively constant ˜1/3.25.
RV = EROA × regurgitant TVI
RV = (2 × 3.14 × R2 × aliasing velocity/mitral velocity) × regurgitant TVI
RV = 2 × 3.14 × R2 × aliasing velocity/3.25 = 1.9 × R2 × aliasing velocity
Using the numbers provided, the RV is 75 mL.
6. A 34-year-old woman with a history of rheumatic heart disease presents for yearly evaluation. She is completely asymptomatic. An echocardiogram shows mitral valve doming in diastole, commissural fusion and chordal retraction, and the mitral valve area by both planimetry and pressure halftime is 1.3 cm2 with a mean gradient of 9 mm Hg. The tricuspid regurgitant peak velocity is 3 m/s. In what disease stage is this patient?
A. Stage A.
B. Stage B.
C. Stage C.
D. Stage D.
6. Answer: C. Current ACC/AHA Guidelines on Valvular Heart Disease have focused on disease staging: at-risk patients (stage A), progressive mild-moderate disease (stage B), severe asymptomatic disease (stage C), and severe, symptomatic disease (stage D). Note that mitral stenosis is now considered severe when valve area is <1.5 cm2 (previously 1.0 cm2). Answer C is, therefore, the correct choice.
7. A 54-year-old man is hospitalized with an acute myocardial infarction. He is taken emergently to the catheterization laboratory, where a completely occluded right coronary artery is found. He undergoes successful stenting. On the third day of hospitalization, he becomes acutely dyspneic and appears diaphoretic. There are no murmurs on clinical examination. An emergency bedside echocardiogram shows hyperdynamic LV function; there is no pericardial effusion. The mitral continuous wave Doppler interrogation shows a dense triangular signal with peak in early systole. The most likely explanation for the patient’s symptoms is:
A. LV free wall rupture.
B. Ventricular septal rupture with large ventricular septal defect.
C. Acute severe mitral regurgitation due to papillary muscle rupture.
D. Acute thrombosis of the coronary stent.
7. Answer: C. While all listed complications may occur early after a myocardial infarction and percutaneous intervention, the presence of a hyperdynamic LV excludes in-stent thrombosis. There is no evidence of pericardial effusion to suggest free wall rupture. A ventricular septal defect is typically associated with a loud systolic murmur, even when acute. The murmur of acute severe mitral regurgitation due to papillary muscle rupture is unimpressive. This is due to rapid equalization of LV and atrial pressures, with little pressure gradient. The typical continuous wave Doppler finding is a triangular-shaped mitral regurgitant signal (correct answer C).
8. A 78-year-old woman has been complaining of worsening dyspnea on exertion for the past 6 months. She has a history of hypertension that is poorly controlled despite treatment with a diuretic, angiotensin receptor blocker and a dihydropyridine calcium channel blocker. Her primary care physician noted a murmur and requested an echocardiogram. This shows presence of a mildly enlarged left ventricle, with calculated ejection fraction of 65%. The aortic valve is sclerotic, with a mean gradient of 10 mm Hg and moderate regurgitation. The mitral annulus and base of mitral valve leaflets are densely calcified, with a mean diastolic gradient of 9 mm Hg at a heart rate of 82 beats/min. The E velocity is 2.1 m/s, with a pressure half-time of 110 ms. The mitral valve area by planimetry in short-axis parasternal view is 1.3 cm2. Which of the following statements is correct?
A. The mitral valve area is best estimated in this patient by the pressure half-time method.
B. Mitral balloon valvuloplasty is indicated in this symptomatic patient.
C. Mitral valve replacement is indicated in this symptomatic patient.
D. Mitral stenosis severity should be reassessed after blood pressure and heart rate are better controlled.
8. Answer: D. Estimation of mitral valve area in this patient is challenging. Direct planimetry measurements are difficult with the background of severe valvular calcification. Pressure half-time is not reliable in assessment of mitral valve area in elderly patients with severe degenerative calcific mitral stenosis, as it is influenced by coexisting diastolic dysfunction. In addition, presence of moderate aortic regurgitation also influences pressure half-time. The mean gradient is consistent with significant mitral stenosis, but the heart rate is fast. Patient’s symptoms may also be due to uncontrolled hypertension. Given all these findings, the next logical step is: control blood pressure, attempt to reduce heart rate, and then reassess mitral stenosis severity.
9. A 46-year-old woman presents with a history of recurring episodes of chest pressure and severe dyspnea. She has been hospitalized four times with similar symptoms. Upon presentation to the hospital, she received chewable aspirin, sublingual nitroglycerin, and underwent emergent ECG, which was unremarkable except for sinus tachycardia. Chest x-ray films confirmed on each occasion presence of pulmonary edema, and she responded well to intravenous diuretic therapy. During her first hospitalization, she underwent emergent catheterization, which showed normal coronary arteries. Left ventriculography demonstrated moderate mitral regurgitation, normal ejection fraction, and no regional wall motion abnormalities. On subsequent admissions, she had negative triple rule-out CT (no pulmonary embolism, no aortic dissection, no coronary occlusion), as well as a negative treadmill exercise stress echocardiography. The latter showed normal left ventricular size, ejection fraction of 63%, and moderate mitral regurgitation at rest; with stress ejection fraction increased to 75%, there were no regional wall motion abnormalities, and mitral regurgitation remained moderate. She is seeking second opinion. On clinical examination, she has a 2/6 apical holosystolic murmur that does not change with Valsalva maneuver or squat-tostand. Which test will help establishing diagnosis in this patient?
A. Transesophageal echocardiography.
B. Adenosine sestamibi scan.
C. Transthoracic echocardiography with amyl nitrite provocation.
D. Coronary spasm study with concomitant echocardiography.
9. Answer: D. This question is modeled on a real case from our clinic. A transesophageal echocardiogram is unlikely to show resting severe mitral regurgitation, given lack of symptoms between spells, physical examination consistent with moderate disease, and previously confirmed moderate regurgitation by both left ventriculography and echocardiography. An adenosine sestamibi scan will not provide information additional to known coronary angiography. Amyl nitrite is used to mimic exercise physiology and unravel dynamic LVOT obstruction in patients suspected with hypertrophic obstructive cardiomyopathy, but clinical examination in her case is not suggestive of this disease (negative Valsalva and squat-to-stand). Acute severe mitral regurgitation has been described with coronary vasospasm and is a cause of flash pulmonary edema. In this patient, coronary vasospasm was induced with Methergine infusion in the catheterization laboratory and was associated with identical symptoms with previous hospital presentations. Acute transient severe mitral regurgitation is also described with DC cardioversion and stress (tako-tsubo) cardiomyopathy.
10. A 92-year-old man is admitted with the sudden onset of severe dyspnea. On clinical examination, he is tachypneic and tachycardic and has a loud holosystolic murmur at the apex. Emergent echocardiography demonstrates a large flail P2 scallop of the mitral valve. He is considered for percutaneous repair with the MitraClip device. Which of the following echocardiographic findings is important in deciding suitability of this procedure?
A. Presence of commissural calcifications.
B. Presence of annular calcifications.
C. Presence of A2 and P2 scallop calcifications at valve tip.
D. Presence of subvalvular calcifications.
10. Answer: C. Commissural and subvalvular calcifications are important in planning mitral balloon valvuloplasty, but not a MitraClip. Mitral annular calcification is common in this age group and is not a contraindication to MitraClip. Presence of leaflet calcification at the device landing zone (in this case A2 and P2) is a contraindication for percutaneous MitraClip repair.
11. Which of the following statements is correct regarding the proximal isovelocity surface area (PISA) method for quantification of mitral regurgitation severity?
A. PISA is best measured at aliasing velocities of 10-30 cm/s.
B. PISA is measured exclusively on apical views.
C. The largest sphere seen during systole is used for calculations.
D. PISA angle correction may be required for mitral regurgitation.
11. Answer: D. Optimal aliasing velocity for PISA is 30-40 cm/s. Values greater than those are associated with small PISA radii, and likely to produce erroneous measurements, while lower aliasing velocities will identify isovelocity shells too far from the regurgitant orifice, where the surface is no longer a hemisphere. PISA should be measured in any view that allows optimal Doppler alignment (parallel with the flow); with eccentric jets parasternal and sometime subcostal views may offer better alignment than the apical window. The PISA radius should be selected to match timing of peak mitral regurgitant velocity, usually occurring close to the T wave on ECG. In general, the angle between mitral valve leaflets is ˜180 degrees at the time of PISA measurements (see Figure 17-10, left panel). However, when the jet originates at the mitral valve commissures in close proximity to the left ventricular wall, there may not be enough space for a full hemisphere to form (see Figure 17-10, right panel). In this case, the true angle must be measured and corrections applied:
2 × &pgr; × R2 × aliasing velocity × &agr;/180 = EROA × peak MR velocity
12. A 29-year-old woman is transferring care to your institution. She has occasional lightheadedness with intense physical activity, but no other cardiovascular history. On clinical examination, she has a 2/6 systolic murmur at the left parasternal border, which increases with Valsalva maneuver. Orthostatic blood pressure measurements are normal. According to the American Society of Echocardiography recommendation for appropriate use of echocardiography, a transthoracic echocardiogram in this patient is:
D. This patient does not fit any category in the current appropriate use guidelines.
12. Answer: A. This patient has symptoms and clinical examination reveals a murmur suggestive of dynamic left ventricular outflow obstruction. Under these circumstances, echocardiography is appropriate.
13. A 36-year-old man with a history of hypertrophic cardiomyopathy complains of worsening dyspnea on exertion. On clinical examination, the apical impulse is sustained, there is a normal split of the second heart sound, and a systolic murmur is heard over the precordial area, increasing with the squat-to-stand maneuver. A transthoracic echocardiogram shows prominent septal hypertrophy with systolic anterior motion of the mitral valve and dynamic obstruction of the left ventricular outflow tract with an estimated late systolic peak gradient of 70 mm Hg at rest. There is an anteriorly directed jet of mitral regurgitation, with prominent Coanda effect. What would you recommend as the next best step?
A. Refer the patient for septal alcohol ablation.
B. Refer the patient for surgical myectomy.
C. Refer the patient for hemodynamic catheterization and coronary angiography.
D. Refer the patient for transesophageal echocardiography.
13. Answer: D. The patient clearly has symptomatic dynamic left ventricular outflow obstruction, and septal reduction therapy (surgical myectomy and septal alcohol ablation) should be considered. However, presence of anteriorly directed jet of mitral regurgitation is concerning for superimposed organic mitral valve pathology, most likely a flail posterior leaflet. Indeed, systolic anterior motion-related mitral regurgitation is usually directed posteriorly. Under the circumstances, mechanism of mitral valve regurgitation must be established to select the optimal approach. If a flail posterior leaflet is confirmed, surgical intervention will be required to correct both the dynamic obstruction and mitral valve organic disease.
14. What is the correct measurement of the pressure half-time of the mitral inflow signal shown in Figure 17-1?
A. Trace 1.
B. Trace 2.
14. Answer: B. Using trace 1 for measuring mitral valve pressure half-time is a common mistake. The first part of the signal is reflective of both left atrial and ventricular pressure, not only mitral stenosis. Current ASE recommendations suggest the use of trace #2.
15. An 82-year-old woman presents with complaints of worsening dyspnea on exertion. Transthoracic echocardiogram demonstrates a mitral mean gradient of 12 mm Hg at a heart rate of 92 beats/min. Three-dimensional TEE left atrial and left ventricular views of the mitral valve at maximum opening in diastole are presented in Figure 17-2. Her Society of Thoracic Surgeons (STS) risk score is 14% for mortality. What is the best next step in her management?
A. Mitral balloon valvuloplasty.
B. Surgical mitral valve replacement.
C. Percutaneous mitral valve replacement.
15. Answer: D. The three-dimensional TEE images demonstrate a heavily calcified mitral valve. This does not appear amenable to valvuloplasty. While surgical or percutaneous replacement may be considered, we note that the high mitral gradient is obtained at a heart rate of 92 beats/min. Considering the significant risk with either interventional procedure (high risk of periprosthetic regurgitation when the mitral annulus is heavily calcified; percutaneous replacement has been described only in case reports), it seems more prudent to reassess a mitral valve gradient when heart rate is better controlled.
16. A 44-year-old man presents for evaluation of dyspnea on exertion. He has no known medical history, and the clinical examination is unremarkable except for hypertension (blood pressure 160/90 mm Hg) and a 2/6 systolic murmur over the precordial area. The M-mode through the mitral valve is obtained from standard parasternal long-axis view (Fig. 17-3). Which of the following statements is correct?
A. Antihypertensive treatment with lisinopril will improve his symptoms.
B. Antihypertensive treatment with a thiazide diuretic will improve his symptoms.
C. Antihypertensive treatment with verapamil will improve his symptoms.
16. Answer: C. The M-mode tracing demonstrates systolic anterior motion of the mitral valve during late systole, consistent with dynamic left ventricular outflow tract obstruction. Afterload reducing agents (lisinopril and amlodipine) and diuretics are likely to exacerbate the obstruction. Nondihydropyridine calcium channel blockers or beta blockers are the treatment of choice.
17. A 49-year-old woman presents with a history of progressively worsening dyspnea. She remembers having frequent throat infections as a child. The electrocardiogram shows atrial fibrillation with an average heart rate of 85 beats/min. A TEE is performed (see Fig. 17-4). Chest x-ray shows normal heart size. Clinical examination is most likely to show: