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Garden-Hose Mitral Regurgitation: A Variant That Can Result in Underestimation of Severity: A Multimodality Imaging Case Study

Published:March 01, 2022DOI:https://doi.org/10.1053/j.jvca.2022.02.033
      The quantitative assessment of mitral regurgitation (MR) by echocardiography has limitations. Cardiac magnetic resonance (CMR) imaging has an emerging role in the quantitation of MR, and preliminary studies indicate that CMR assessment may more accurately quantify MR and better correlate with postsurgical left ventricular reverse remodeling. The authors here report a case of MR in which multimodality imaging with CMR and transesophageal echocardiography was crucial in accurately diagnosing the severity of MR when transthoracic and provocative supine bike echocardiography underestimated the degree of MR in a unique variant known as “garden-hose” MR.

      Key Words

      THE ASSESSMENT of the mechanism and severity of mitral regurgitation (MR) by echocardiography has limitations. Both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) may underestimate the severity of MR for various reasons. An eccentric jet or poor image quality can result in underappreciation of MR on TTE. Additionally, during TEE assessment of MR, the anesthetic effects on preload and afterload can result in a decrease in the severity of MR. Given that MR is afterload-dependent when clinically suspected, additional provocation with exercise ergometry or phenylephrine may be required to evaluate dynamic variation in MR. Cardiac magnetic resonance (CMR) has a role in quantifying the severity of regurgitation when there is a discrepancy among other modalities.
      The authors report a patient with MR in whom TTE and supine bike echocardiography underestimated the degree of regurgitation. They discuss how multimodality imaging was crucial in diagnosing and accurately quantifying the type and severity of mitral regurgitation.

      Clinical Case

      A 54-year-old male construction worker presented with intermittent episodes of exertional dyspnea and orthopnea with lower extremity edema of 1-year duration. His functional capacity declined significantly from being able to do heavy-duty construction work to requiring disability within 1 year. Other comorbidities included hyperlipidemia and hypertension. His physical examination was unremarkable except for a holosystolic murmur in the subaxillary space. A pulmonary evaluation was negative. Coronary arteries were normal on invasive angiography. The left ventricular end-diastolic pressure was 17 mmHg. The initial TTE color Doppler showed moderate MR, with an effective regurgitant orifice area of 0.2 cm2 and a regurgitant volume of 27 mL (Fig 1; Video 1). The mitral inflow E wave was 39 cm/s, and the E/A ratio was 0.7. The end-diastolic diameter was 6.2 cm. Due to concerns for dynamic MR, a supine bike stress test was done that failed to show more-than-moderate MR (Fig 2; Video 2). A subsequent CMR was done to evaluate for other cardiac pathology, which incidentally revealed significant ≥MR and a dilated left ventricle (indexed end-diastolic volume = 129 mL/m2. The calculated regurgitation volume was 57 mL, and the regurgitation fraction was 37% (Fig 3; Video 3).
      Fig 1
      Fig 1Transthoracic echocardiogram. Color Doppler and spectral Doppler images demonstrated moderate mitral regurgitation (Video 1). The E/A ratio of 0.8 and the peak E velocity of 38.6 cm/s were indicative of normal left atrial pressure.
      Fig 2
      Fig 2Supine bike echocardiography. Color Doppler TTE (top panel) and Spectral Doppler (bottom panel) at rest, workload of 100 watts and recovery did not demonstrate an increase in the severity of MR. The MR severity reduced in the recovery phase on supine bike ergometry (Video 2). MR, mitral regurgitation; TTE, transthoracic echocardiogram.
      Fig 3
      Fig 3Quantitation of MR volumes by cardiac magnetic resonance imaging: LV, EDV, and ESV are calculated by summation of discs method, and the LVSV is determined. Aortic forward volume then is determined by measuring the flow by aortic through-plane using phase velocity mapping. MR then is estimated by deducting the aortic forward volume from the LVSV. Cine MRI images generally are not reliable for estimation of MR severity (Video 3). EDV, end-diastolic volume; ESV, end-systolic volume; LV, left ventricle; LVSV, left ventricular stroke volume; MR, mitral regurgitation; MRI, magnetic resonance imaging; SV, stroke volume.

      E-Challenge

      What are possible explanations for the discordance between the echocardiographic and the CMR data presented?

      Clinical Course

      Due to the incongruence between the CMR and TTE in this otherwise active patient with marked symptoms, a TEE was performed for further evaluation. The TEE showed prolapse of the posterior (P2) segment of the mitral valve, with a flail portion of the leaflet and significant MR (Fig 4; Video 4). The MR jet had a “garden-hose” effect, with directional change between an eccentric anteriorly directed jet and a centrally directed jet later in systole. The vena contracta was 0.5 cm, with an effective regurgitant orifice area 0.38 cm2 by the proximal isovelocity surface area, and a regurgitant volume of 55 mL. Additionally, a dynamic increase in regurgitation severity was seen with phenylephrine. As a result of the authors’ findings, the patient was diagnosed with severe Carpentier type II mitral valve regurgitation with garden-hose effect secondary to mitral valve prolapse. The patient was referred for operative repair of the mitral valve (Fig 5). The patient had complete relief of symptoms within 2 months after repair and continued to do well a year later.
      Fig 4
      Fig 4Transesophageal echocardiography. Color Doppler images demonstrate the “garden-hose” effect with a directional change between an eccentric anteriorly directed jet to a central jet later in the cardiac cycle. Prolapse of P2 segment clearly is demonstrated on 3D echocardiography. (Video 4). 3D, 3-dimensional.
      Fig 5
      Fig 5Robotic mitral valve repair was performed with neochordae insertion to P2 segment and release of secondary chordae of the A2 segment to optimize mitral valve coaptation: Annuloplasty was performed with a 36-mm band.

      Discussion

      The authors’ patient had persistent and severe symptoms that were suggestive of intermittent flash pulmonary edema. In the absence of other clinical pathology, occult MR was suspected, and multimodality imaging was used to clarify the diagnosis. This ultimately revealed a previously undetected variant of dynamic MR termed “garden-hose MR.” This phenomenon is not a commonly recognized entity, and it has a unique signature with a marked directional variation and dynamic jet flow that mimics the appearance of a hose spraying around the left atrium. This occurs due to dynamic changes in the orientation of the regurgitation orifice as a result of increased leaflet prolapse in systole. The authors propose that this effect resulted in an underestimation of MR severity on TTE and supine bike echocardiography.
      Supine bike echocardiography can be used to assess the hemodynamic consequences of MR under varying loading conditions when dynamic MR is suspected. A review of 2 studies of dynamic MR, with supine bike testing, demonstrated that only 30%-to-32% of patients had an increase in regurgitant volume during the examination.
      • Stoddard MF
      • Prince CR
      • Dillon S
      • et al.
      Exercise-induced mitral regurgitation is a predictor of morbid events in subjects with mitral valve prolapse.
      ,
      • Magne J
      • Lancellotti P
      • Piérard LA.
      Exercise-induced changes in degenerative mitral regurgitation.
      One study further analyzed the remaining 68% of patients without an increase and showed that 26% actually had decreased MR volume while the other 42% showed no change in MR volume during the examination.
      • Magne J
      • Lancellotti P
      • Piérard LA.
      Exercise-induced changes in degenerative mitral regurgitation.
      Although supine bike testing can show worsening MR, there also remains a large percentage of patients who can have a reduction of MR or no observable change in MR. As seen in the authors’ patient, this resulted in the false-negative supine bike test that did not accurately demonstrate the severity of MR. It has been shown that supine exercise testing can increase preload and left ventricular end-diastolic volume due to the mechanical pumping of the legs during exercise, as well as a decrease in systemic vascular resistance and increase in cardiac output, all of which can result in a reduction in MR severity.
      • Cnota JF
      • Mays WA
      • Knecht SK
      • et al.
      Cardiovascular physiology during supine cycle ergometry and dobutamine stress.
      Discrepancies among imaging modalities increasingly are a concern in the era of multimodality imaging. In the STITCH trial, there was only a modest correlation between TTE and TEE (r: 0.51) when assessing MR grade.
      • Grayburn PA
      • She L
      • Roberts BJ
      • et al.
      Comparison of transesophageal and transthoracic echocardiographic measurements of mechanism and severity of mitral regurgitation in ischemic cardiomyopathy (from the surgical treatment of ischemic heart failure trial).
      The correlation between echocardiography and CMR is poor-to-modest (r = 0.4-0.84), with an absolute agreement in the range of 36%-to-70%.
      • Uretsky S
      • Argulian E
      • Narula J
      • et al.
      Use of cardiac magnetic resonance imaging in assessing mitral regurgitation: Current evidence.
      The concordance between the methods was even lower in severe MR compared to mild MR.
      • Uretsky S
      • Gillam L
      • Lang R
      • et al.
      Discordance between echocardiography and MRI in the assessment of mitral regurgitation severity: A prospective multicenter trial.
      In general, echocardiography is more likely to overestimate the severity of MR compared to CMR.
      • Uretsky S
      • Argulian E
      • Narula J
      • et al.
      Use of cardiac magnetic resonance imaging in assessing mitral regurgitation: Current evidence.
      Uretsky et al retrospectively evaluated CMR and echocardiographic measures in patients who underwent surgery for MR. The concordance was only 22% in severe MR, in which both echocardiography and CMR were read as “severe MR.” There was a 33% discordance with echocardiography reading “severe MR” and CMR reading “mild MR.”
      • Uretsky S
      • Gillam L
      • Lang R
      • et al.
      Discordance between echocardiography and MRI in the assessment of mitral regurgitation severity: A prospective multicenter trial.
      During postsurgical follow-up, the patients with “severe MR” on CMR were found to have more reverse remodeling compared to those with only “moderate MR'' on CMR. There were significant differences between the reduction in left ventricular end-diastolic volume among the categories of mild, moderate, and severe MR as determined by CMR (–32 mL, –55 mL, and –140 mL, respectively).
      • Uretsky S
      • Gillam L
      • Lang R
      • et al.
      Discordance between echocardiography and MRI in the assessment of mitral regurgitation severity: A prospective multicenter trial.
      The study concluded that CMR was better in quantifying MR volume and more accurately predicted reverse remodeling.
      • Uretsky S
      • Gillam L
      • Lang R
      • et al.
      Discordance between echocardiography and MRI in the assessment of mitral regurgitation severity: A prospective multicenter trial.
      Given the poor prognosis of untreated symptomatic severe MR, an accurate diagnosis is essential for management. When applicable, cardiac magnetic resonance imaging (MRI) can help to clarify the severity of MR. Additionally, it is important to assess the dynamic nature of MR under increased afterload conditions (stress echocardiography, phenylephrine). Clinicians also must bear in mind the limitations of the various imaging modalities and the variable agreement among them. As in this patient, it is important to integrate information from all available imaging and apply it to the individual clinical scenario.

      Conclusion

      This case described an unusual mechanism of MR, that is, garden-hose MR, with a characteristic variation of jet directionality that can result in underestimation of the severity on TTE. The utilization of multimodality imaging, including CMR and TEE, was crucial to understanding the severity and mechanism in this unique variant of MR.

      Conflict of Interest

      None.

      Appendix. Supplementary materials

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      References

        • Stoddard MF
        • Prince CR
        • Dillon S
        • et al.
        Exercise-induced mitral regurgitation is a predictor of morbid events in subjects with mitral valve prolapse.
        J Am Coll Cardiol. 1995; 25: 693-699
        • Magne J
        • Lancellotti P
        • Piérard LA.
        Exercise-induced changes in degenerative mitral regurgitation.
        J Am Coll Cardiol. 2010; 56: 300-309
        • Cnota JF
        • Mays WA
        • Knecht SK
        • et al.
        Cardiovascular physiology during supine cycle ergometry and dobutamine stress.
        Med Sci Sports Exerc. 2003; 35: 1503-1510
        • Grayburn PA
        • She L
        • Roberts BJ
        • et al.
        Comparison of transesophageal and transthoracic echocardiographic measurements of mechanism and severity of mitral regurgitation in ischemic cardiomyopathy (from the surgical treatment of ischemic heart failure trial).
        Am J Cardiol. 2015; 116: 913-918
        • Uretsky S
        • Argulian E
        • Narula J
        • et al.
        Use of cardiac magnetic resonance imaging in assessing mitral regurgitation: Current evidence.
        J Am Coll Cardiol. 2018; 71: 547-563
        • Uretsky S
        • Gillam L
        • Lang R
        • et al.
        Discordance between echocardiography and MRI in the assessment of mitral regurgitation severity: A prospective multicenter trial.
        J Am Coll Cardiol. 2015; 65: 1078-1088

      Linked Article

      • Mitral Regurgitation—When One View Isn't Enough
        Journal of Cardiothoracic and Vascular AnesthesiaVol. 36Issue 7
        • Preview
          Mitral regurgitation (MR) is dynamic, with systolic flow variations during different phases of the cardiac cycle.1 The mechanisms and severity of valvular regurgitation most commonly are assessed using quantitative and semiquantitative 2-dimensional (2D) transthoracic echocardiographic (TTE) parameters. Accurate grading and mechanistic understanding of MR are essential in order to guide appropriate downstream treatment decisions.2 It is critical to accurately diagnose and repair MR before the onset of left ventricular dysfunction.
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