Post-CABG tricuspid regurgitation: TEE to detect a structural cause

Differentiating the etiology of post-CPB tricuspid regurgitation

The onset of severe tricuspid regurgitation (TR) during weaning from cardiopulmonary bypass (CPB) poses a major diagnostic challenge for the surgical team. Although functional causes related to volume variations, rhythm disturbances, or myocardial dysfunction predominate, the possibility of an iatrogenic structural lesion must be imperatively excluded. Rapid management of these complications requires a precise distinction between cardiac pathology induced by the surgical context and acute structural rupture.

This article reports the clinical case of a 63-year-old patient who developed severe tricuspid regurgitation after isolated coronary artery bypass grafting. The objective is to illustrate how intraoperative transoesophageal echocardiography (TEE) allows, despite the absence of a systematic indication for this surgery, the identification of a rare structural rupture—in this instance, a tricuspid valve chordal rupture—masked by an initial suspicion of functional etiology.

This study tests the hypothesis that the systematic use of intraoperative TEE, even during isolated coronary artery bypass grafting, is essential for the early diagnosis and immediate surgical correction of rare structural causes. The patient underwent repair via neochord implantation combined with a 26 mm tricuspid annuloplasty ring, allowing for satisfactory biventricular functional recovery at the end of the procedure.

Methodology and clinical management

This clinical case reports the experience of a 63-year-old patient, classified as ASA 4, admitted for coronary revascularization via isolated coronary artery bypass grafting. Preoperative evaluation, including transthoracic echocardiography (TTE), showed a left ventricular ejection fraction of 60%, normal right ventricular function, and trivial tricuspid regurgitation (TR).

The surgical protocol followed a standard bypass procedure with cardiopulmonary bypass (CPB). Myocardial protection was achieved by antegrade blood cardioplegia via the aortic root, with an induction dose of 1 L followed by intermittent injections every 10 to 15 minutes. The initial CPB time was 89 minutes, with an aortic cross-clamp time of 68 minutes.

The intraoperative diagnosis relied on the systematic use of transoesophageal echocardiography (TEE):

• Alert phase: During weaning from CPB, TEE revealed severe TR with right ventricular volume overload, initially suspected to be functional.
• Structural confirmation: In-depth TEE exploration identified a tricuspid valve chordal rupture, associated with a flail posterior leaflet.
• Surgical correction: After re-establishment of CPB, inspection confirmed the rupture of a primary chord of the posterior leaflet, associated with an abnormal papillary muscle. The repair consisted of neochord implantation followed by the placement of a 26 mm tricuspid annuloplasty ring.
• Final evaluation: The success of the intervention was validated by a final intraoperative TEE showing mild residual TR with normalization of biventricular function and size.

Intraoperative diagnosis and management of acute tricuspid regurgitation

During an isolated coronary artery bypass grafting in a 63-year-old patient, intraoperative transoesophageal echocardiography (TEE) revealed severe tricuspid regurgitation (TR) during weaning from cardiopulmonary bypass (CPB). Initially suspected to be functional due to right ventricular dysfunction, in-depth echocardiographic analysis identified a structural etiology: a flail posterior leaflet of the tricuspid valve, associated with an anteriorly directed jet.

Immediate reintervention under CPB confirmed the acute rupture of a primary chord of the posterior leaflet, originating from an abnormal papillary muscle. Surgical repair consisted of neochord implantation and the placement of a 26 mm tricuspid annuloplasty ring.

The final TEE demonstrated normalization of biventricular size and systolic function, allowing for uncomplicated weaning from CPB. This case highlights the diagnostic value of systematic TEE, even outside of class I indications, to distinguish functional causes from iatrogenic structural causes during routine cardiac surgeries.

Intraoperative transesophageal echocardiography: a safety imperative, even in routine surgery

The clinical observation presented here illustrates a critical situation: the sudden onset of severe tricuspid regurgitation (TR) during weaning from cardiopulmonary bypass (CPB) after an isolated coronary artery bypass graft. While post-CPB TR is classically considered functional, this case serves as a reminder that structural etiology, although rare, should never be ruled out. Here, the acute rupture of a chordae from an abnormal papillary muscle necessitated immediate re-intervention.

This study highlights a major limitation of current guidelines: the lack of classification of intraoperative transesophageal echocardiography (TEE) as a class I recommendation for isolated bypass. This variability in practice is based on a 'routine' dogma that can mask unpredictable iatrogenic or structural complications. The strength of this report lies in the demonstration that only targeted echocardiographic investigation allowed for the differentiation of the mechanism (flail of the posterior leaflet) and guided precise surgical correction via neochord and annuloplasty.

The main limitation lies, by nature, in the unique character of the reported case. It is not a cohort study, and the data do not allow for the establishment of a prevalence. However, this case constitutes solid proof of concept in favor of systematic TEE monitoring, calling into question the very notion of 'routine' surgery.

Clinical synthesis: the contribution of TEE post-bypass

During an isolated coronary artery bypass graft in a 63-year-old patient, intraoperative transesophageal echocardiography (TEE) identified a ruptured tricuspid valve chordae, masked by an initial suspicion of functional etiology. Immediate repair, including the placement of ePTFE neochords and a 26 mm annuloplasty ring, reduced severe regurgitation to a mild residual grade, facilitating uncomplicated weaning from CPB.

Specifically, for the practitioner:

• Systematize TEE: Even in isolated coronary surgery, TEE remains the gold standard tool for distinguishing reversible functional failure from rare structural damage, thus avoiding inappropriate CPB weaning.
• Beware of appearances: When faced with acute post-CPB tricuspid regurgitation, never presume a purely functional origin; meticulous inspection via TEE may reveal iatrogenic or anatomical structural abnormalities requiring immediate correction.
• Structural vigilance: This case underscores the importance of screening for anatomical abnormalities, such as accessory papillary muscles, during any intracardiac intervention to prevent unexpected structural complications.

Technical glossary

Coronary artery bypass graft (CABG): Surgical myocardial revascularization procedure consisting of creating a bypass between the aorta or a mammary artery and the stenosed coronary arteries.

Cardiopulmonary bypass (CPB): Cardiopulmonary diversion technique ensuring blood circulation and oxygenation during temporary cardiac arrest to allow for surgical intervention.

Transesophageal echocardiography (TEE): Ultrasound imaging method using a probe introduced into the esophagus to obtain optimal visualization of cardiac structures in real time, essential for intraoperative monitoring.

Flail tricuspid valve leaflet: Valvular coaptation defect characterized by a tricuspid valve leaflet that prolapses into the right atrium due to the rupture of its chordal attachments.

Tendinous chordae: Fibrous structures connecting the valve leaflets to the papillary muscles, ensuring the competence of the tricuspid valve during ventricular systole.

Tricuspid annuloplasty ring: Prosthetic device implanted around the tricuspid annulus to restore its geometry and improve leaflet coaptation in cases of structural insufficiency.

Right ventricular dysfunction: Impairment of the contractile function of the right ventricle, identified here by intraoperative echocardiographic imaging during difficulties in weaning from cardiopulmonary bypass.

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