Graphical abstract
Keywords: Aortic regurgitation, Aortic valve fenestrations, Doppler imaging, Echocardiography
Highlights
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Aortic valve fenestrations should be considered as a rare cause of AR.
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Timing of surgical intervention for chronic asymptomatic severe AR warrants serial TTE.
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TTE measurements of LV dimensions and EF help decide timing of aortic valve repair.
Introduction
Aortic regurgitation (AR) results from diverse pathologies in the aortic valve cusps and/or root. One of the contemporary causes of AR is aortic valve fenestrations. In the past, it has been documented as a surgical or pathological finding.1, 2, 3 The literature that is available on the mechanism of regurgitation and its imaging findings is inadequate. Moreover, the 2017 American Society of Echocardiography guidelines for native valvular regurgitation do not include or elaborate on fenestrations as a cause of AR.4 As a result, they may go unrecognized on echocardiographic imaging. It is therefore important for cardiologists to understand the mechanism and recognize the suggested imaging findings of aortic valve fenestrations.
Case Presentation
An asymptomatic 60-year-old man presented for routine screening and was found to have moderate to severe AR on echocardiography. Medical history was significant for deep vein thrombosis due to prothrombin gene mutation and rivaroxaban use. Physical exam revealed regular, bounding carotid and radial pulses with blood pressure of 160/70 mm Hg. De Musset (head bobbing) and Lincoln signs (leg bobbing) of AR were present. On cardiac exam, diastolic murmur without thrill was present in the aortic area. Pulmonary exam was unremarkable. Electrocardiogram showed normal sinus rhythm with incomplete right bundle branch block.
Index transthoracic echocardiography (TTE) showed trileaflet aortic valve with moderate-severe AR (Figure 1A, Video 1), mildly enlarged left ventricular (LV) chamber size (LV end-diastolic diameter [LVEDD] = 58 mm, LV end-systolic diameter [LVESD] = 36 mm), and normal LV ejection fraction (EF = 65%, three-dimensional [3D] LV endodiastolic volume [LVEDV] = 206 mL, LV endosystolic volume [LVESV] = 73 mL). Sinus of Valsalva was mildly dilated at 41 mm (40 mm upper normal), and so were the sinotubular junction, 39 mm (35 mm upper normal), and proximal ascending aorta, 39 mm (38 mm upper normal). Holodiastolic flow reversal was observed both in the descending and abdominal aorta, suggesting severe AR by TTE, which was then confirmed by transesophageal echocardiography (TEE; effective regurgitant orifice area was calculated as 0.29 cm2, and regurgitant volume [RV] was 77 mL by proximal isovelocity surface area; Figure 1B-E, Videos 2-4). Bicuspid valve, infective endocarditis, connective tissue disorders, and rheumatic etiology were ruled out on subsequent testing. Thereafter, the patient was managed conservatively and followed up.
Figure 1.
Echocardiographic images. (A) Two-dimensional TTE zoomed apical 3-chamber view without (left) and with (right) color flow Doppler, demonstrates AR with flow convergence. The AR jet severity is difficult to quantify because of the jet eccentricity. (B) Two-dimensional TEE, midesophageal level, zoomed short-axis view (80°) of the aortic valve without (left) and with (right) color flow Doppler, demonstrates that the AR originates between the noncoronary and left coronary cusps. (C) Two-dimensional TEE, midesophageal level, zoomed long-axis view (137°) with color flow Doppler, demonstrates an eccentric AR jet directed toward the LV septum with a proximal flow convergence. (D) Two-dimensional TEE, midesophageal level, zoomed long-axis view (137°) with color flow Doppler, baseline color scale shifted down to 37.7 cm/sec, demonstrates a proximal isovelocity surface area radius r = 0.71 cm. (E) Continuous-wave Doppler spectrum of the AR jet demonstrates a maximal regurgitant velocity of 4.1 m/sec and regurgitant time-velocity integral of 264.0 cm. The calculated effective regurgitant orifice area is 0.29 cm2; RV is 77 mL.
Subsequent TTE was performed 6 months later. Worsening LV dimensions/volume (LVEDD = 64 mm, LVESD = 37 mm, two-dimensional [2D] LVEDV = 222 mL, LVESV = 81 mL, EF = 63%), particularly the significant increase in LVEDD to 64 mm, met the criteria for surgical intervention. Aortic regurgitation quantitation by follow-up TTE using the continuity equation was RV = 144 mL and regurgitant fraction = 62%. Aortic root measurements were 41 mm at the sinus of Valsalva, 40 mm at the sinotubular junction, and 40 mm at the proximal ascending aorta. Computed tomography chest angiography revealed a mildly enlarged ascending aorta (mid–ascending aorta diameter of 42 mm).
Preoperative TEE showed a significant eccentric AR jet noted between the left and noncoronary cusps by both 2D and 3D echocardiography (Graphical Abstract, Videos 5 and 6). Transgastric imaging revealed flow convergence above the left or noncoronary cusps, raising the possibility of fenestrations versus perforation (Graphical Abstract, Video 7). Given the absence of endocarditis history, fenestrations were felt to be more likely. The eccentric nature of the jet suggested that the mechanism was less likely due to aortic root dilatation, where one would expect central regurgitation.
Intraoperative surgical findings were significant for multiple unruptured fenestrations in the noncoronary cusp of the aorta (Figure 2). Aortic valve repair was not attempted due to a thin and fragile valve with multiple fenestrations. A bioprosthetic valve was implanted. No regurgitation was noted postoperatively. Histopathological examination of the excised valve revealed mild to moderate calcification and fibrosis of the valve with presence of Lambl excrescences.
Figure 2.
Intraoperative surgical findings. (A) Trileaflet aortic valve visualized during surgery focused on the noncoronary cusp (arrow). (B) The yellow box surrounds the zoomed view of the noncoronary cusp of the aortic valve. (C) Close-up image of the noncoronary cusp reveals multiple fenestrations (arrows).
Discussion
Aortic cusp fenestrations are common but infrequently produce valvular regurgitation due to their location. They occur near the coaptation area of the cusps, and hence overlap by adjacent leaflets during diastole prevents backflow.5 Coexistence of annular dilatation or cusp prolapse can cause regurgitation. Annular dilation causes loss of coaptation and hence backflow. In some cases, the cusp tissue between the fenestration and aortic wall tears, leading to ruptured fenestration.6 Rupture of a fenestration leading to cord prolapse is usually seen almost exclusively in acute AR.7,8
In this case, there was no cord rupture or cusp prolapse. The patient presented with chronic asymptomatic AR that progressed over 6 months. We hypothesize that multiple fenestrations in the setting of a mildly dilated ascending aorta may have been responsible for the development and progression of AR. In terms of the aortic root in this case, the anatomy itself is close to a type Ib mechanism,9,10 but the dilatation is mild and its size is slightly over the normal range of similar body size male subjects. Aortic valve coaptation looked preserved by TEE 2D grayscale images. Thus, although there might be multiple contributing factors, an important associated mechanism was considered fenestrations. We speculate the fenestrations may have gradually enlarged due to wear and tear without rupture, which caused the increase in RV.
The rate of progression of AR is difficult to predict in the setting of fenestrations and aortic dilatation as there are no good natural history studies. An individualized approach and serial follow-up by imaging exams are important for patient management.
Fenestrations should be suspected when there is tissue dropout within the body of the cusp accompanied by color flow penetrating the defect. This can be additionally investigated using 3D TEE. Eccentric AR with proximal flow convergence above the valve in the absence of aortic root dilatation, perforation from endocarditis, and obvious cusp prolapse should arouse suspicion for aortic cusp fenestrations. It may be confirmed only during surgery or on pathological examination post–valve replacement.
When identified during surgery, aortic valve fenestrations are rarely repaired due to the high degree of complexity and risk of unfavorable outcomes. In rare cases, especially a single fenestration without rupture, one could consider the use of an autologous pericardial patch to close it. Recent studies have shown that recurrence of fenestration in trileaflet aortic valves following repair is low.11 Aortic valve repair can be considered in patients with pliable, noncalcified trileaflet aortic valve with aortic root dilation or cusp prolapse and in some cases of bicuspid aortic valve.12
Conclusion
Aortic valve fenestrations are a rare cause of severe AR that should be considered in cases with eccentric regurgitation in the absence of other clinically identifiable etiology. Identifying fenestrations by echocardiography is challenging, and hence they are often confirmed at the time of surgery or on pathological exam. Repair is attempted only in a subset of patients based on surgical inspection of the valve by the performing cardiac surgeon. Valvular replacement is done in cases when repair is not possible.
Ethics Statement
The authors declare that the work described has been carried out in accordance with the Mayo IRB policies.
Consent Statement
The authors declare that since this was a non-interventional, retrospective, observational study utilizing de-identified data, informed consent was not required from the patient under an IRB exemption status.
Funding Statement
This case report publication was supported and funded by Mayo Clinic Arizona Cardiovascular Clinical Research Center.
Disclosure Statement
The authors report no conflict of interest.
Footnotes
Supplementary data to this article can be found online at https://doi.org/10.1016/j.case.2022.11.009.
Supplementary Data
Two-dimensional TTE zoomed apical 3-chamber view without (left) and with (right) color flow Doppler demonstrates AR with flow convergence. The AR jet severity is difficult to quantify because of the jet eccentricity but was estimated as moderate to severe grade with an uncertain etiology.
Two-dimensional TEE, midesophageal level, zoomed short-axis view (80°) of the aortic valve without (left) and with (right) color flow Doppler demonstrates that the AR originates between the noncoronary and left coronary cusps. A small mobile structure is also seen on the left coronary cusp near the commissure between the left and noncoronary cusps.
Two-dimensional TEE, midesophageal level, zoomed long-axis view (137°), demonstrates a small mobile structure attached to the left coronary cusp and suspected perforation.
Two-dimensional TEE, midesophageal level, zoomed long-axis view (137°) with color flow Doppler, demonstrates an eccentric AR jet directed toward the LV septum with a proximal flow convergence through a suspected perforation of the leaflet tip.
Two-dimensional TEE, midesophageal level, zoomed x-plane image with color flow Doppler, demonstrates eccentric regurgitation that originates between the noncoronary and left coronary cusps.
Three-dimensional TEE, midesophageal level with color flow Doppler viewed from the perspective of the aorta, demonstrates that the AR originates near the edge of the noncoronary cusp and left coronary cusps.
Two-dimensional TEE, deep transgastric images without (left) and with (right) color flow Doppler demonstrate flow convergence above the left or noncoronary cusps with an eccentric AR jet toward LV septum.
References
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Associated Data
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Supplementary Materials
Two-dimensional TTE zoomed apical 3-chamber view without (left) and with (right) color flow Doppler demonstrates AR with flow convergence. The AR jet severity is difficult to quantify because of the jet eccentricity but was estimated as moderate to severe grade with an uncertain etiology.
Two-dimensional TEE, midesophageal level, zoomed short-axis view (80°) of the aortic valve without (left) and with (right) color flow Doppler demonstrates that the AR originates between the noncoronary and left coronary cusps. A small mobile structure is also seen on the left coronary cusp near the commissure between the left and noncoronary cusps.
Two-dimensional TEE, midesophageal level, zoomed long-axis view (137°), demonstrates a small mobile structure attached to the left coronary cusp and suspected perforation.
Two-dimensional TEE, midesophageal level, zoomed long-axis view (137°) with color flow Doppler, demonstrates an eccentric AR jet directed toward the LV septum with a proximal flow convergence through a suspected perforation of the leaflet tip.
Two-dimensional TEE, midesophageal level, zoomed x-plane image with color flow Doppler, demonstrates eccentric regurgitation that originates between the noncoronary and left coronary cusps.
Three-dimensional TEE, midesophageal level with color flow Doppler viewed from the perspective of the aorta, demonstrates that the AR originates near the edge of the noncoronary cusp and left coronary cusps.
Two-dimensional TEE, deep transgastric images without (left) and with (right) color flow Doppler demonstrate flow convergence above the left or noncoronary cusps with an eccentric AR jet toward LV septum.