A 76-year-old male presents for a second opinion about treatment of his mitral regurgitation. He was initially diagnosed with mitral valve prolapse and mitral regurgitation (MR) 15 to 20 years ago and has been followed closely. The most recent echocardiogram, performed by his cardiologist, demonstrated an ejection fraction of 65% with severe MR and no other significant valve disease. Pulmonary function tests done the same day demonstrated an FEV1 of 1.90 L with a volume of 83.4%. He states that for the last 20 years he gets out of breath if he tries to run for a bus. Outside of that, he can function as a musician, travel, and lift his equipment without any impairment to his physical activity. There is no orthopnea, paroxysmal nocturnal dyspnea, or lower extremity edema. His past medical history is otherwise significant for stage III liver cancer, which has responded to chemotherapy and radiation with no evidence of recurrent disease. His cardiologist recommended he go forward and should consider intervention on his mitral valve.
On examination, his blood pressure is 178/90 mmHg with a heart rate of 68 bpm. His height = 64 inches, weight = 142 lbs (BSA = 1.69 cm2). He appears well and is in no apparent distress. His lungs are clear bilaterally. Cardiac exam reveals a normal S1, S2 with a regular rate and rhythm, and a 4/6 murmur at the apex radiating to the axilla. There is no edema. His 5-meter walk time in the office is 5 seconds.
Transthoracic Echocardiogram reveals a left ventricular end-diastolic (LVED) and end-systolic (LVES) diameters of 5.7 cm and 3.2 cm respectively, left atrial volume = 60 ml/m2, LF ejection fraction (LVEF) = 67%, relative wall thickness of 0.32 (normal), LV mass index = 120 gm/m2 (increased). There is bileaflet prolapse of the mitral valve with ruptured chordae to the P1-P2 scallops with associated flail leaflet. There are multiple regurgitant jets. One jet is posteriorly directed associated with anterior leaflet prolapse. Another jet is anterior/medially directed associated with the posterior flail leaflet. By volumetric Doppler methods, the total diastolic stroke volume = 160 cc with regurgitant volume calculated as 85 cc (regurgitant fraction = 53%) with effective regurgitant orifice area = 49 mm2.
Laboratory tests reveal a normal complete blood count, biochemistry profile and NT-ProBNP = 111.2 pg/mL.
The correct answer is: B. Stress echocardiography to assess his symptoms.
Choice A is incorrect.
Although "watchful waiting" has been the treatment strategy for asymptomatic patients with severe organic MR, there is growing evidence that patients with no or minimal symptoms not only have lower operative mortality, but would have improved long-term outcomes if surgery was performed prior to the onset of symptoms1 . Propensity score matching of early surgery and initial medical management groups in the MIDA registry confirmed higher survival after early surgery (HR, 0.52 [95% CI, 0.35-0.79], P = .002). In the absence of symptoms, 10-year survival was also better with early surgery, (84% [95% CI, 78%-90%]) compared to initial medical management (78% [95% CI, 72%-85%], P = .04).1 Thus, both the ACC/AHA guidelines2 and the most recent 2020 update of the Expert Consensus Decision Pathway on the Management of Mitral Regurgitation3 state that stress echocardiography may be used to help define symptoms, exercise capacity, MR severity, pulmonary artery systolic pressure, and LV/RV responses to exercise.
Choice B is correct.
Both the ACC/AHA guidelines2 and the most recent 2020 update of the Expert Consensus Decision Pathway on the Management of Mitral Regurgitation3 state that stress echocardiography may be used to help define symptoms, exercise capacity, MR severity, pulmonary artery systolic pressure, and LV/RV responses to exercise.
There are two indications for stress echocardiography for primary mitral regurgitation (MR): severe MR with no symptoms and non-severe MR with symptoms.1,2,4,5 For severe MR with no symptoms, a positive test is indicated by symptoms, systolic pulmonary artery pressure increase, and failure to increase left ventricular ejection fraction. For non-severe MR with symptoms, a positive test is indicated by severe MR with symptoms, or symptoms unrelated with MR (i.e. regional wall motion abnormalities). For primary MR, abnormal exercise stress echo findings that have been associated with poor outcomes include: SPAP ≥60 mmHg, change in LVEF <5%, change in global longitudinal strain <2%, and change in MR severity of ≥1 grade (effective regurgitant orifice area ≥10–13 mm2) and limited RV contractile recruitment (quantified by tricuspid annular plane systolic excursion (TAPSE <18 mm). There are important caveats to the interpretation of SPAP. Resting and exercise values may increase with age, and will depend on the workload achieved. Finally, MR severity and SPAP may decrease immediately on termination of the test, thus underestimating these parameters when using exercise stress testing.
Exercise is the test of choice for most patients. As a general rule, any patient capable of physical exercise should be tested with an exercise modality, as this preserves the integrity of the electromechanical response and provides valuable information regarding functional status. Performing echocardiography at the time of exercise also allows links to be drawn among symptoms, cardiovascular workload, wall motion abnormalities, and hemodynamic responses, such as pulmonary pressure and transvalvular flows and gradients. Exercise echocardiography can be performed using either a treadmill or bicycle ergometer protocol. In most cases, dobutamine should not be used instead of exercise to assess the dynamic behavior of MR because its effects on MR severity are not physiologic.1,2
Choice C is incorrect.
Increased BP correlates with higher left ventricular pressure. In turn, this exposes the mitral valve to higher physical stress. In a recent study of patients in the United Kingdom followed for 10 years, systolic BP was continuously related to the risk of developing MR. For each 20 mmHg increment in systolic BP, there was a 26% higher risk of mitral regurgitation (hazard ratio [HR] 1.26; CI 1.23, 1.29).6 It is likely that not only does patient's blood pressure contribute to the severity of regurgitation on the transthoracic echocardiogram, but may have contributed to the degeneration of the valve and resulting flail leaflet. However, treatment of the blood pressure, although indicated, is unlikely to cause resolution of the severe MR.
Choice D is incorrect.
Mitral valve repair is associated with improved outcomes compared to replacement for primary MR2. A recent study supported prior studies, showing that independent parameters which predicted a replacement (versus a repair) in primary MR included: patient age, moderate-severe LV dysfunction, prior cardiac surgery, multiple segment prolapse (including anterior leaflet prolapse and bileaflet prolapse), mitral calcification, leaflet retraction, and the experience of the performing surgeon.7 Thus, the likelihood of successful repair in this patient with multi-leaflet involvement is likely <95%.
Choice E is incorrect.
The patient responded to cancer therapies and no evidence of recurrent disease is referenced. History and physical examination clearly demonstrate a robust and highly functional 76-year-old that should be considered for all therapeutic options.
FOLLOW-UP:
The patient underwent a stress echocardiogram to assess symptoms and the hemodynamic significance of his MR. On a standard Bruce Treadmill Exercise protocol, his resting blood pressure was 134/68 mmHg, heart rate = 64 bpm. He exercised for 3'50" (below average functional capacity) with BP = 168/76 mmHg, heart rate = 110 bpm. The test was terminated because of shortness of breath. On echocardiography, baseline measurements were: LVEF = 68%, SPAP = 33 mmHg, EROA = 94 mm2. Following termination of exercise, his echocardiographic measurements were: LVEF = 72%, SPAP = 58 mmHg, and EROA = 120 mm2.
Given the reduced functional capacity and significant echocardiographic changes, surgical intervention was recommended.
Educational grant support provided by Abbott Structural Heart
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References
- Suri RM, Vanoverschelde JL, Grigioni F, et al. Association between early surgical intervention vs watchful waiting and outcomes for mitral regurgitation due to flail mitral valve leaflets. JAMA 2013;310(6):609-16.
- Nishimura RA, Otto CM, Bonow RO, et al. 2017 AHA/ACC Focused Update of the 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 Clinical Practice Guidelines. Circulation 2017 Jun 20;135(25):e1159-e1195.
- Bonow RO, O'Gara PT, Adams DH, et al. 2020 Focused Update of the 2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Report of the American College of Cardiology Solution Set Oversight Committee. J Am Coll Cardiol 2020 May 5;75(17):2236-2270.
- Lancellotti P, Pellikka PA, Budts W, et al. The Clinical Use of Stress Echocardiography in Non-Ischaemic Heart Disease: Recommendations from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr 2017 Feb;30(2):101-138.
- Flint N, Raschpichler M, Rader F, et al. Asymptomatic Degenerative Mitral Regurgitation: A Review. JAMA Cardiol 2020;5(3):346–355.
- Rahimi K, Mohseni H, Otto CM, et al. Elevated blood pressure and risk of mitral regurgitation: A longitudinal cohort study of 5.5 million United Kingdom adults. PLoS Med 2017;14(10):e1002404.
- Coutinho GF, Correia PM, Branco C, Antunes MJ. Long-term results of mitral valve surgery for degenerative anterior leaflet or bileaflet prolapse: analysis of negative factors for repair, early and late failures, and survival. Eur J Cardiothorac Surg 2016;50(1):66–74.
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