Brief Case Description

The patient is a 38 year-old male with a past medical history of end-stage renal failure on dialysis. He is a candidate for kidney transplantation and preoperative work-up revealed a systolic murmur of mitral regurgitation.

Transthoracic echocardiography showed type II mitral valve dysfunction with posterior leaflet prolapse. Parasternal long axis view with color Doppler interrogation of the mitral valve showed an anteriorly directed jet and mitral regurgitation was graded severe. Regurgitant orifice area was 84 mm2. Left ventricle was severely dilated with an end diastolic diameter of 6.5 cm. Left ventricular ejection fraction was 50 %. Doppler echocardiography showed two distinct jets (two-chamber and four-chamber views), one anteriorly directed due to posterior leaflet prolapse and one posteriorly directed secondary to associated type IIIb dysfunction. Echocardiography showed only minimal tricuspid regurgitation. The right ventricle was normal in size and function.


 

The patient was referred for reconstructive mitral valve surgery. According to the current guidelines, this patient should have benefited from an earlier surgical intervention before left ventricular ejection fraction decreases below 60 %.

Preoperative cardiac catheterization showed normal coronaries. Pulmonary artery pressure was 50/20 mmHg.

Operative Procedure

Intraoperative Transesophageal Echocardiography

Intraoperative transesophageal echocardiography confirmed the diagnosis of posterior leaflet prolapse involving the P3 segment (mid esophageal long axis and four-chamber views). Doppler echocardiography showed an anteriorly directed jet and mitral regurgitation was graded severe. There was also a tethering of the anterior leaflet and the non-prolapsing segments of the posterior leaflet due to severe ventricular dilatation.


 

Mitral Valve Analysis

Following the left atriotomy, annular sutures were placed to optimize the exposure of the mitral valve. We first performed valve analysis using Carpentier's reference point technique. We assessed the motion of P1 segment by pulling its free edge upward with a nerve hook. The P1 segment was not prolapsing as its free edge was not overriding the plane of the mitral annulus. Using a second hook, other valve segments were examined in a systematic manner and compared to P1 to verify if they were prolapsing. In this case, valve analysis confirmed the prolapse of the P3 segment due to chordae rupture and elongation. The anterior leaflet was not prolapsing. There was a tethering of all valvular segments except P3 due to severe ventricular dilatation as seen in the video. The mitral annulus was moderately dilated.




Following this complete echocardiographic and operative valve analysis, we can summarize the pathophysiological triad as follows:

Etiology: Fibroelastic deficiency (FED): the short history of systolic murmur and morphology of the valve on echocardiography and during intraoperative valve analysis were all indicators of this etiology. The young age of the patient, however, was not in favor of FED.

Lesions: Chordae elongation and rupture, secondary annular dilatation

Dysfunction: Type II - P3

There was also an associated type IIIb dysfunction secondary to severe ventricular dilatation.

Reconstructive Procedure

This was a case of extensive prolapse of P3 segment as more than one third of the length of the free edge of P3 was involved. Therefore we performed a partial resection of this segment. This technique has the advantages of excising most pathological tissues, creating a more normal geometry of the leaflet, and decreasing the tension on the reconstructed leaflet.

We first placed two 4-0 stay sutures at the level of normal chordae at the limits of the prolapse area.




Approximately 2 mm from these normal chordae, a trapezoidal resection of P3 segment was performed. We were able to preserve the indentation between P2 and P3 segments. Following trapezoidal resection, secondary chordae close to the edges of the resection were cut to facilitate leaflet mobilization. As shown below, the height of remnants P2 and P3 was 14 mm and 15 mm respectively. The gap between the two segments was 12 mm.




We used annular plication technique to reduce the size of the posterior annulus and to approximate these two segments. Leaflet continuity was restored with 5-0 monofilament sutures.




Valve analysis following reconstruction showed a similar height between reference P1 and the reconstructed leaflet segment suggesting a perfect result. The valve analysis using two hooks is critical to confirm that there is no residual prolapse and that we have not induced any restricted leaflet motion.


 

This was further confirmed by the saline test which showed a symmetrical line of coaptation parallel to the posterior aspect of the annulus. The minimal residual regurgitation on saline test was due to the fact that the left ventricle was not fully distended.


 

Finally, a remodeling annuloplasty was performed. We first measured the intercommissural distance using a 32 mm sizer which was the appropriate size.




Second, we measured the height of the anterior leaflet. The 32 mm sizer was positioned and covered the entire surface area of the anterior leaflet. Therefore, a 32 mm Carpentier Edwards Physio ring was selected and implanted as shown in the video. The two operative views of the anterior leaflet show its maximal height at A2 level and its entire surface area.





A repeat saline test was performed and showed a symmetrical line of coaptation. As previously mentioned, the minimal residual regurgitation on the saline test was due to the fact that the left ventricle was not fully distended.




Postbypass Transesophageal Echocardiography

Mid esophageal long axis and four-chamber views showed a competent mitral valve with no residual regurgitation.