Unearthing the Tunnel

History of Presentation

A 75-year-old man presented to the valve clinic (Columbia Structural Heart and Valve Center) with activity-limiting dyspnea on moderate exertion and poor functional capacity (New York Heart Association functional class II-III). Physical examination was pertinent for a systolic murmur (left lower sternal border). He was afebrile, with blood pressure of 128/80 mm Hg and a heart rate of 60 beats/min in an atrial paced rhythm. His lung examination was clear, and there was edema of his lower extremities. Results of laboratory investigations showed indirect hyperbilirubinemia and microscopic hematuria.

Past Medical History

The patient had a past medical history of coronary artery bypass surgery and mitral valve repair with a 30-mm Carpentier-Edwards Physio ring in 2010. The patient underwent bone marrow transplantation in 2011 for immunoglobulin G lambda multiple myeloma. In 2012, the patient had osteomyelitis and methicillin-resistant Staphylococcus aureus mitral valve endocarditis, which were treated medically initially. He subsequently had symptomatic severe mitral regurgitation after 8 months that required redo mitral valve surgery with a 25-mm Mosaic bioprosthetic valve (Medtronic).

Differential Diagnosis

The differential diagnosis included cardiomyopathy (ischemic vs valvular), mitral regurgitation (central vs paravalvular), perivalvular abscess, pulmonary hypertension, and primary lung disease.

Investigations

A transesophageal echocardiogram (TEE) was performed and showed a severe paravalvular leak (PVL) at the lateral commissure (Figure 1A). With 3-dimensional (3D) multiplanar reconstruction, the vena contracta area measured 27 to 31 mm^{, with maximum and minimum dimensions of 8.5 mm and 3.9 mm, respectively. Advanced 3D photorealistic and transillumination rendering (EPIQ systems, X8-2T probe, Philips Medical Systems) revealed the entry origin of the PVL, which was a channel tracking under the annulus of the surgical valve (}Figures 1B to 1F, Video 1). The entrance to the channel was at the midposterior (P2) annulus, and blood filled the channel exiting at the lateral commissure. Left ventricular systolic function and cavity size were normal. The right ventricle was moderately dilated, with moderately reduced systolic function. Cardiac computed tomography (CT) was performed using volume acquisition that confirmed the presence of a subannular channel (Figure 2). There was no significant coronary artery disease or signs of active endocarditis. Right-sided heart catheterization showed mildly elevated right- and left-sided filling pressures with moderate postcapillary pulmonary hypertension (mean right atrial pressure, 22 mm Hg; right ventricular pressure, 7/11 mm Hg; mean pulmonary artery pressure, 48 mm Hg; and mean pulmonary capillary wedge pressure, 28 mm Hg).

Figure 1

Preprocedural Transesophageal Echocardiogram

(A) Baseline 2-dimensional (2D) and color Doppler transesophageal echocardiogram in the commissural view demonstrating the paravalvular leak (PVL). (B to E) Baseline 3-dimensional (3D) transesophageal echocardiogram rendering in en face view showing the jet entrance (blue arrow), the periannular channel (yellow arrows), and the jet exit site (red arrows). (F) Paravalvular jet demonstration in en face view using multislice automated cropping (arrows as in B to E). Ao = aorta.

Figure 2

Preprocedural Cardiac Computed Tomography

Cardiac computed tomography in the short axis at the level of the mitral annulus showing the entrance and exit point of the paravalvular leak jet across the channel.

Management

He was evaluated by the multidisciplinary heart team and was deemed at high risk for surgical intervention. The decision was made to proceed with percutaneous PVL closure. Cardiac CT images were used for assessing the channel course and confirming the TEE findings, in addition to sizing the defect (Figures 3A to 3C).

Figure 3

Sizing of the Paravalvular Leak Defect by Cardiac Computed Tomography

Preprocedural cardiac computed tomography with multiplanar reconstruction and analysis of the periannular channel at the junction with the left atrium. The crosshairs show the paravalvular leak channel in the (A and B) long axis and (C) short axis. (C) Cross-sectional image of the paravalvular leak channel with measurement (9.3 × 4.7 mm). A 12-mm Amplatzer Vascular Plug II (Abbott) device was selected for the procedure. AO = aorta; AV = aortic valve; LA = left atrium; LV = Left ventricle; Max = maximum; Min = minimum.

Two-dimensional (2D) and 3D TEE guidance was used to optimize transseptal puncture, and the PVL was crossed using an Agilis catheter. The wire path followed the course of the channel along the posterior annulus and entered the left ventricle at the P2 region of the annulus (Figures 4A and 4B). A 12-mm Amplatzer Vascular Plug II (AVP II, Abbott) closure device was positioned using fluoroscopic and TEE guidance, the distal cap and barrel of the device were markedly deformed within the narrow channel (Video 2). Following release of the proximal cap within the left atrium, extensive 2D and 3D imaging revealed multiple trivial PVL jets (Figure 5, Video 3). No intraprocedural complications were noted.

Figure 4

Intraprocedural Imaging

(A) Intraprocedural 3-dimensional transesophageal echocardiogram in the surgeon’s view showing the guide catheter across the channel. The red dotted line shows the course of the wire as it travels through the channel. (B) Fluoroscopy showing the wire traveling through the periannular channel.

Figure 5

Postprocedural 3-Dimensional Transesophageal Echocardiogram

Postprocedure 3-dimensional photorealism rendering Amplatzer Vascular Plug II (AVP II, Abbott) device (yellow arrow) and the residual trace paravalvular leak jets.

Discussion

PVL is a rare but serious complication after surgical valve replacement and can lead to heart failure and/or hemolytic anemia.1² It occurs in 7% to 17% of mitral valve replacements. Surgical reintervention for PVLs is associated with a high risk of morbidity and mortality; therefore, percutaneous treatment of PVLs has become first-line therapy for most symptomatic patients.3

In this case, our patient’s heart failure symptoms were attributed to the significant mitral prosthetic PVL. The use of advanced TEE imaging software with a photorealism 3D-rendering technique and transillumination images with transparency enhanced the echocardiographic visualization of the complex geometry of the periannular channel, which could have been a sequela of his previous endocarditis.4⁵ In addition, placing the virtual light source above and around the mitral annulus, and the use of transillumination rendering, assisted in highlighting the exit and entrance of the periannular channel.6

Because of the unusual course of the PVL and the varying size of the channel, we chose an AVP II device with a “cap” that would sit over the exit site within the left atrium and a barrel that would fill the periannular channel. Advanced TEE imaging in conjunction with cardiac CT allowed for robust preprocedural planning and a successful procedural result.7

Follow-Up

Transthoracic echocardiography before discharge showed a well-positioned vascular plug with trace paravalvular regurgitation. Cardiac CT showed a well-positioned vascular plug with no prosthetic entanglement or complication (Figures 6A and 6B). At 1-month follow-up, the patient remained well, with resolution of his symptoms. Laboratory findings showed new hematuria immediately after the procedure that improved over the following 3 weeks.

Figure 6

Postprocedural Cardiac Computed Tomography

Follow-up cardiac computed tomography showing the Amplatzer Vascular Plug II (AVP II, Abbott) device (red dotted circle) in (A) the 2-chamber view and (B) the short-axis view at the level of the mitral prosthetic sewing ring. Abbreviations as in Figure 3.

Conclusions

In this complex, high-risk patient with mitral PVL, the role of multimodality imaging was key to the success of complex structural interventions. The enhancement of image quality with novel technology, such as transillumination rendering, improved our ability to diagnose the condition, localize lesions, and guide structural interventions.