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Mitral Valve Repair Failure Diagnosed with a Sudden Change in Jet Direction from Posterior to Anterior: Inconsistent with Systolic Anterior Motion

Kaminski, Anna DO; Eaton, Michael P. MD; Knight, Peter MD; Stern, David MD; Sifain, Andrew MD

doi: 10.1213/ANE.0000000000000407
Cardiovascular Anesthesiology: Echo Rounds
Continuing Medical Education

From the Department of Anesthesiology, University of Rochester, Rochester, New York.

Accepted for publication June 9, 2014.

Funding: None.

The authors declare no conflicts of interest.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website.

Reprints will not be available from the authors.

Address correspondence to Anna Kaminski, DO, Department of Anesthesiology, University of Rochester, 601 Elmwood Ave., Box 604, Rochester, NY 14624. Address e-mail to Intub8you@gmail.com.

A 58-year-old man with a history of hypertension and symptomatic mitral valve prolapse presented for mitral valve repair. Consent was obtained from the patient for publication of this report. After induction of anesthesia, transesophageal echocardiogram (TEE) imaging demonstrated a hyperdynamic left ventricle with an ejection fraction of 65% and moderate mitral regurgitation (MR), with prolapse of P2 and P3 segments (Video 1, Supplemental Digital Content 1, http://links.lww.com/AA/A975). Pulsed wave Doppler interrogation of the left upper pulmonary vein showed systolic blunting. The anterior mitral leaflet in the midesophageal (ME) long-axis view in mid-systole was 2.6 cm in length. The distance from the coaptation point to the septum measured 3.2 cm and the length of the posterior coapted leaflet measured 1.2 cm. The ratio of anterior leaflet length to posterior leaflet length was 2.16. Mild aortic insufficiency was also noted and had not been previously described in preoperative TEE at our institution.

A midline sternotomy was performed and hypothermic (32°C) cardiopulmonary bypass (CPB) was instituted with bicaval cannulation. Eight polytetrafluoroethylene neochords (Gore-Tex CV5 suture, Gore-Tex; Gore and Associates Inc., Flagstaff, AZ) were placed from the posteromedial papillary muscle to the atrial side of the posterior leaflet (P2), reducing the height of the posterior leaflet to about 1.0 cm as measured from the annulus to the leading edge of the leaflet. A posterior flexible annuloplasty band (Simplici-T, Medtronic, Minneapolis, MN) was placed and secured before closure of the left atrium. The native mitral valve was not altered. Postrepair TEE interrogation initially showed no significant residual MR.

However, during sternal closure, a moderate degree of recurrent MR with a posteriorly directed jet consistent with systolic anterior motion (SAM) of the anterior mitral leaflet was noted. Interventions to alleviate the SAM were undertaken, including initiation of an esmolol infusion and rapid IV infusion of crystalloid solution. Repeat imaging demonstrated gradual resolution of the SAM. Before chest closure, we noted that the MR jet had changed and was now directed anteriorly (Fig. 1, Video 2, Supplemental Digital Content 2, http://links.lww.com/AA/A976; Video 3, Supplemental Digital Content 3, http://links.lww.com/AA/A977). Additional images were obtained, which showed what appeared to be a ruptured chord prolapsing into the left atrium (Fig. 2, Video 3, Supplemental Digital Content 3, http://links.lww.com/AA/A977). CPB was reinstituted and the heart was reopened. Two of the neochords were found to have separated from the papillary muscle due to slipping of the sutures. These were removed and replaced with 3 additional neochords. The valve again appeared competent when tested by fluid distention of the left ventricle, and the left atrium was closed. The patient was then successfully weaned from bypass.

Figure 1

Figure 1

Figure 2

Figure 2

The final TEE images showed trace MR and no SAM. The velocity time integral (VIT) of the transmitral inflow in the ME aortic valve long-axis view demonstrated a mean mitral valve gradient of 4 mm Hg. The patient was taken to the intensive care unit, recovered uneventfully, and was subsequently discharged on postoperative day 4.

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DISCUSSION

SAM is a known complication of mitral valve repair (4%–10% of cases).1 The regurgitant jet associated with it is characteristically described as posteriorly directed. Our patient developed SAM, despite attention to reducing the height of the posterior leaflet with the repair. It was somewhat fortuitous that this patient developed SAM, which required additional imaging, otherwise the repair failure would have occurred at a time when our attention was no longer focused on TEE, or perhaps after discontinuation of imaging. There were no hemodynamic changes associated with the repair failure, and our only indication that there was an acute change in the patient’s condition was the reversal in the direction of the regurgitant jet. Although published studies have demonstrated long-term durability of neochords,2 the incidence of acute perioperative failure is unclear.

A comprehensive assessment of the mitral valve should always be performed after repair. It is important that the echocardiographer determines the presence and severity of any residual stenosis or regurgitation because these may impact outcome. This should include imaging in the ME 4-chamber, 2-chamber, long-axis and commissural views, as well as spectral and color Doppler analysis of the transmitral flow to assess the presence of residual stenosis or regurgitation. As per American Society of Echocardiography guidelines on intraoperative assessment of mitral valve repair and replacement, the following variables should be included in the evaluation: (1) peak transvalvular velocity, (2) VTI of transvalvular velocity, (3) mean transvalvular gradient, (4) pressure half-time, (5) and effective mitral valve area. Methods to assess the mitral valve orifice area include the continuity equation (mitral valve area = [left ventricular outflow tract radius]2 × π × left ventricular outflow tract VTI]/mitral valve VTI), and planometry. The initial assessment of regurgitant jets postoperatively typically begins with imaging in a ME long-axis view. In systole, a posteriorly directed jet appears to hug the atrium opposite the side of the aortic valve. All ME views should be evaluated in the presence of MR to delineate the exact direction of the MR jet. Newer TEE probes, which enable 3-dimensional imaging with color flow Doppler, may aid the surgeon in deciding potential therapies.

The transgastric left ventricular 2-chamber or long-axis views allow for full assessment of the mitral valve apparatus (Fig. 3). In these views, a neochord appears as a bright, hyperechoic filament, when compared with a native chorda tendinae, which is a linear structure extending from the papillary muscle to the undersurface of the mitral valve leaflets.

Figure 3

Figure 3

The use of neochords began as early as the 1960s, initially using pericardium. Over time, however, it was discovered that pericardial fibers would thicken and shorten resulting in pseudoprolapse and repair failure.3 The use of neochords for mitral valve repair was not widespread until David et al.4 published their extensive experience in 1996. Since then, others have demonstrated the durability of this material.2

Major complications have been reported with polytetrafuoroethylene sutures including inappropriate chord measurements and knot slipping.5 Although post-bypass chordal length cannot be accurately predicted preoperatively, there are methods for its estimation. One such method was described by Mandegar et al.6 and included the preoperative measurement of the distance from the head of the papillary muscle to the point of coaptation of the leaflets. An article recently published by Huang et al. also describes a method using real-time 3-dimensional echocardiography to predict the length of the artificial chords. In this article, the lengths were determined by measuring from the expected coaptation point to the respective papillary muscle segment/scallop, i.e., from the anterior papillary muscle to A1/P1, or from the posterior papillary muscle to A3/P3, and from the nearest papillary muscle to A2/P2.7 Sizing remains the most concerning aspect because inaccuracies will result in failure of coaptation of the anterior and posterior leaflets.

In conclusion, this case demonstrates that continued imaging in the post-CPB period after a mitral valve repair is important for the detection of acute repair failure. A change in jet direction should immediately raise concern and suspicion for a new pathology.

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Clinician’s Key Teaching Points

By Nikolaos J. Skubas, MD, Roman M. Sniecinski, MD, and Martin J. London, MD

  • The surgical management of degenerative mitral regurgitation (MR) usually includes repair of the prolapsing or flail leaflets with placement of an annuloplasty ring at the mitral annulus. The primary role of intraoperative transesophageal echocardiogram (TEE) after bypass is to assess the completeness of the repair by determining whether residual MR is present and, if so, quantifying its severity.
  • One potential source of MR after mitral valve repair is systolic anterior motion (SAM) of the anterior mitral leaflet, which produces left ventricular (LV) outflow tract obstruction. In the midesophageal (ME) long-axis (LAX) view, the MR jet is posteriorly directed, away from the anterior mitral leaflet and toward the lateral left atrial wall. Treatment of SAM can most often be accomplished medically by augmentation of intravascular volume using IV fluids, increases in afterload using vasocontrictors, and decreases in LV contractility using short-acting β-blockers.
  • In this case, mitral valve repair was accomplished by the insertion of artificial chord (neochords) between the tip of the posterior papillary muscle and the atrial side of the prolapsing P2 scallop. Intraoperative TEE examination at the time of sternal closure revealed SAM that resolved with crystalloid infusion and esmolol. Shortly thereafter, color flow Doppler in the ME LAX view demonstrated a new MR jet, directed over the anterior leaflet toward the atrial septum, that differed from the previous, SAM-related posteriorly directed jet. TEE examination revealed that one of the neochords had ruptured and cardiopulmonary bypass was reinstituted to repair it successfully.
  • Artificial neochords are being increasingly used to reduce the prolapse of a leaflet segment and restore coaptation of mitral leaflets below the mitral annulus. However, this technique may fail if the length of the neochord is excessive or a knot slips. Even when other causes of residual MR are detected, careful attention to the integrity of neochords placed during the repair is warranted in the post-bypass period.
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DISCLOSURES

Name: Anna Kaminski, DO.

Contribution: This author helped design the study and write the manuscript.

Attestation: Anna Kaminski approved the final manuscript.

Name: Michael P. Eaton, MD.

Contribution: This author helped write the manuscript.

Attestation: Michael P. Eaton approved the final manuscript.

Name: Peter Knight, MD.

Contribution: This author helped write the manuscript.

Attestation: Peter Knight approved the final manuscript.

Name: David Stern, MD.

Contribution: This author helped write the manuscript.

Attestation: David Stern approved the final manuscript.

Name: Andrew Sifain, MD.

Contribution: This author helped write the manuscript.

Attestation: Andrew Sifain approved the final manuscript.

This manuscript was handled by: Martin J. London, MD.

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REFERENCES

1. Crescenzi G, Landoni G, Zangrillo A, Guarracino F, Rosica C, LaCanna G, Alfieri O. Management and decision making strategy for systolic anterior motion after mitral valve repair. J Thorac Cardiovasc Surg. 2009;37:320–5
2. Chiappini B, Sanchez A, Noirhomme P, Verhelst R, Rubay J, Poncelet A, Funken JC, El Khoury G. Replacement of chordae tendineae with polytetrafluoroethylene (PTFE) sutures in mitral valve repair: early and long-term results. J Heart Valve Dis. 2006;15:657–63
3. Frater RW, Vetter HO, Zussa C, Dahm M. Chordal replacement in mitral valve repair. Circulation. 1990;82:IV125–30
4. David TE, Armstrong S, Ivanov J. Chordal replacement with polytetrafluoroethylene sutures for mitral valve repair: a 25-year experience. J Thorac Cardiovasc Surg. 2013;145:1563–9
5. Ibrahim M, Rao C, Athanasiou T. Artificial chordae for degenerative mitral valve disease: critical analysis of current techniques. Interact Cardiovasc Thorac Surg. 2012;15:1019–32
6. Mandegar MH, Yousefnia MA, Roshanali F. Preoperative determination of artificial chordae length. Ann Thorac Surf. 2006;82:348–49
7. Huang HL, Xie XJ, Fei HW, Xiao XJ, Liu J, Zhuang J, Lu C. Real-time three-dimensional transesophageal echocardiography to predict artificial chordae length for mitral valve repair. J Cardiothorac Surg. 2013;8:137

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