A 66-year-old man underwent mitral valve (MV) repair (annuloplasty and single neochord placement), tricuspid valve (TV) ring annuloplasty, and a modified Cox-maze procedure through a minimally invasive right thoracotomy approach. Preprocedural intraoperative transesophageal echocardiography (TEE) revealed severe mitral regurgitation with flail P2 segment and moderate tricuspid regurgitation with annular dilation. There was mild central aortic regurgitation (AR) graded by vena contracta (VC) measurement. After uneventful surgical repair and separation from cardiopulmonary bypass (CPB), TEE showed no evidence of stenosis or significant regurgitation in the repaired MV or TV. However, there was a second AR jet in addition to the previous central regurgitation. By 2-dimensional color-flow Doppler, the new AR jet was at or near the noncoronary cusp (NCC) and left coronary cusp commissure (Fig. 1; Supplemental Digital Content, Video 1, http://links.lww.com/AA/B122). Analysis of 3-dimensional (3D) full-volume and 3D color full-volume data sets revealed a possible NCC perforation (Fig. 2; Supplemental Digital Content, Video 2, http://links.lww.com/AA/B123). The AR was graded as moderate by the pressure half-time (PHT) method (PHT = 470 milliseconds) using continuous-wave Doppler of the central AR jet in the deep transgastric view. The risks and benefits of surgical AR correction were weighed: repair or replacement may have required a partial or full sternotomy for surgical access and CPB reinitiation. The team elected for conservative management with close follow-up. The patient was tracheally extubated on the day of surgery and discharged home on postoperative day 6. Transthoracic echocardiography at 3-month follow-up revealed trace mitral regurgitation, trace tricuspid regurgitation, and moderate-to-severe AR (PHT 475 milliseconds).
This case illustrates the importance of using multiple echocardiographic modalities in the diagnosis of aortic valve (AV) pathology. Two-dimensional imaging and 2D color-flow Doppler in the midesophageal AV long and short-axis imaging planes suggested AR at the NCC/left coronary cusp commissure or perforation of the NCC. However, in the midesophageal AV long axis or short axis, significant acoustic shadowing of the left ventricular outflow tract from MV prosthetic material can prevent adequate assessment of AR jets. Three-dimensional imaging and 3D with color-flow Doppler evaluation supported the diagnosis of cusp perforation and allowed quantification of functional regurgitant orifice areas (Fig. 3).
After cardiac surgery, increased regurgitation in a nonoperative valve should prompt careful evaluation for possible iatrogenic etiologies using all available modalities. After MV surgery, the left coronary cusp and NCC are the most frequently reported sites of AV cusp injury.1 There are no reports of AV cusp perforation as a direct result of TV surgery although the tricuspid and aortic annuli are also in close proximity. This may reflect either the low rate of isolated TV repair or surgical techniques that avoid suture placement near the septal tricuspid annulus and therefore minimize manipulation of tissues near the atrioventricular node and the aortic annulus. Nevertheless, the proximity of the TV and AV conveys the possibility of damage in these cases also.
Alternatively, aortic annular distortion with impaired cusp coaptation may cause new AR after adjacent valve surgery.2 The aortic and mitral annuli are anatomically coupled; changes in aortic annular dynamic geometry after MV repair have been described.3 However, this potential cause of new AR has not been pursued in our case because of clear evidence of NCC damage on TEE images.
In the case of multiple AR jets, assessment by jet width to left ventricular outflow tract diameter ratio, VC, and proximal isovelocity surface area are not additive and should not be used4; however, it is logical to consider the overall AR grade to be at least equal to that of the largest individual jet, whether graded by VC or jet width to left ventricular outflow tract diameter ratio. Diastolic flow reversal in the middescending aorta and PHT provides additional supporting evidence but are less definitive for acute AR severity; holodiastolic flow reversal is specific for severe AR only but not sensitive, and PHT is dependent on pressure gradients and generally only supports more quantitative evidence of mild or severe AR.4 Quantification of regurgitant fraction (not done for this patient) can assist in severity grading.4
Within the 3D color data set, we have assessed the functional regurgitant orifice area in diastole (maximal regurgitant flow) by aligning axes to perpendicularly transect NCC perforation and central AR with planimetered area tracing of the functional orifices at the interface of color Doppler flow with gray cusp tissue (Fig. 3). The planimetered functional areas for multiple jets are additive for quantitative grading5; planimetry in 3D color data sets by transthoracic echocardiography in chronic AR has been found to correlate well with grading of AR severity by both cardiac magnetic resonance imaging (with 3D Doppler functional area ≥0.5 cm2 corresponding to severe AR)6 and aortography (3D Doppler functional area >0.4 cm2 = moderate and >0.6 cm2 = severe),7 although quantification with this method has not yet been validated for TEE.
In our case, we recognized the limitation of VC measurement with multiple jets in the post-CPB TEE. PHT measurement provided additional support to our estimation of increased AR severity post-CPB compared with the pre-CPB TEE AR assessment by VC. Subsequently, we performed confirmatory 3D functional regurgitant orifice area assessment.
For this patient, long-term follow-up was paramount because the development of left ventricular dysfunction in chronic AR correlates with increased mortality. However, assessment of chronic AR by PHT is complicated by compensatory left ventricular compliance changes and progressive volume overload, which alter the diastolic pressure gradient and assessment of regurgitant flow.4 Overall, this case underscores the diagnostic challenges of multiple AR jets and potential advantages and disadvantages of 3D TEE.
Clinician’s Key Teaching Points
By Roman M. Sniecinski, MD, Nikolaos J. Skubas, MD, and Martin J. London, MD
- The aortic valve sits in the center of the base of the heart. Given its proximity to their annuli, there is a risk of iatrogenic aortic valve injury during surgery on either of the mitral and tricuspid valves.
- Routine measurements used to evaluate a single aortic regurgitant jet are the area of the neck of the jet (vena contracta; severe if >0.6 cm) or its width to left ventricular outflow tract diameter ratio (severe if >65%). These are not generally additive. After mitral surgery, aortic regurgitant jets may not be easily imaged in the midesophageal aortic valve long-axis view because of acoustic shadowing. Quantification of multiple aortic regurgitation jets is challenging.
- In this case, after mitral repair, a new aortic regurgitant jet was imaged in the noncoronary cusp of the aortic valve, apparently caused by an iatrogenic perforation. This was diagnosed by seeing 2 distinct jets immediately after separation from cardiopulmonary bypass: preexisting central and one through the noncoronary cusp. In the deep transgastric long-axis view, a 3D full-volume data set (with color Doppler) was acquired, and the area of each jet was planimetered by using an aortic valve en face view.
- Quantifying multiple aortic regurgitant jets is challenging for the intraoperative echocardiographer. However, the planimetered 3D areas are additive, and summed areas >0.6 cm2 have been shown to correlate well with severe aortic regurgitation as assessed by aortography.
Name: Anne D. Cherry, MD.
Contribution: This author helped analyze the data and write the manuscript.
Attestation: Anne D. Cherry approved the final manuscript.
Name: Alina Nicoara, MD, FASE.
Contribution: This author helped analyze the data and write the manuscript.
Attestation: Alina Nicoara approved the final manuscript.
Name: Scott H. McQuilkin, DO, MHPE.
Contribution: This author helped conduct the study and analyze the data.
Attestation: Scott H. McQuilkin approved the final manuscript.
Name: Jeffrey G. Gaca, MD.
Contribution: This author helped conduct the study.
Attestation: Jeffrey G. Gaca approved the final manuscript.
Name: J. Mauricio Del Rio, MD.
Contribution: This author helped conduct the study and write the manuscript.
Attestation: J. Mauricio Del Rio approved the final manuscript.
This manuscript was handled by: Martin J. London, MD.
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