Author + information
- Published online June 4, 2018.
- Kyung-Jin Kim, MD, PhD,
- Hyung-Kwan Kim, MD, PhD∗ ( )(, )
- Jun-Bean Park, MD, PhD,
- Ho-Young Hwang, MD, PhD,
- Yeonyee E. Yoon, MD, PhD,
- Yong-Jin Kim, MD, PhD,
- Goo-Young Cho, MD, PhD,
- Kyung-Hwan Kim, MD, PhD,
- Dae-Won Sohn, MD, PhD and
- Hyuk Ahn, MD, PhD
- ↵∗Cardiovascular Center, Division of Cardiology, Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
Degenerative mitral valve (MV) disease is the major cause of mitral regurgitation (MR) (1). Transthoracic echocardiography (TTE) is accurate in the diagnosis and localization of MV prolapse (1). Although TTE localization of prolapse at the 6 segments of leaflets is well established (2), no detailed and specific echocardiographic description of MR coming from anterolateral commissural prolapse (ACP) or posteromedial commissural prolapse (PCP) has been reported.
The medical records of 202 consecutive patients who underwent isolated MV repair for degenerative MR were retrospectively reviewed, of whom 54 undergoing isolated commissural MR repair were selected. After 18 patients were excluded (1 previous MV repair, 15 multiple scallops prolapse, 2 poor image quality), 36 were finally included.
Localization of the involved scallops/commissures was assessed in 4 standard transthoracic 2-dimensional (2D) views. In the surgical report, Carpentier classification with 2 commissural segments was adopted to localize prolapsed segments. The surgical findings were used as the reference. Comparisons between 2 groups were performed using the Mann-Whitney U test or Fisher exact test, as appropriate. A 2-sided p value <0.05 was considered significant.
Among 36 patients (mean age 56 years; n = 27 men), 25 showed isolated commissural prolapse (8 ACP, 17 PCP) (Figure 1A). PCP occurred more frequently than ACP (23 [63.9%] vs. 13 [36.1%]), and there were no significant differences in clinical and echocardiographic features. Surgical techniques used included commissural closure (34 of 36), annuloplasty (32 of 36), leaflet resection (2 of 36), chordal resection (10 of 36), and chordal replacement (7 of 36). Correct diagnosis of commissural MR was made in only 13 patients (4 of 13 [30.8%] ACP, 9 of 23 [39.1%] PCP), a lower value than that of scallop prolapse (112 of 124 [90.3%]), reflecting the diagnostic challenge of commissural MR.
TTE suggesting commissural MR was characterized by the 4 standardized imaging planes. In the parasternal long-axis view, the prolapsed segments were found in only one-half of the patients (50.5%; 4 of 13 ACP, 14 of 23 PCP), among whom the integrity of the leaflet margin was mostly intact (72.2%; 2 of 4 ACP, 11 of 14 PCP). MR flow acceleration on the left ventricular (LV) side was found in only 6 (16.7%). The common regurgitant jet flow patterns included: 1) spreading widely into the left atrium (LA) (25.0%); and 2) a V-shaped, double jet flow just below the MV (19.4%). A posteriorly directed regurgitant flow was mostly observed in ACP (46.2%), but PCP showed diverse flow patterns. In the parasternal short-axis view at the MV level, the prolapsed segment was observed in 21 (58.3%; 7 of 13 ACP, 14 of 23 PCP). The characteristic flow patterns were: 1) a V-shaped, double jet flow (27.8%; 4 of 13 ACP, 6 of 23 PCP); 2) a posteromedially directed regurgitant flow (5 of 13 ACP, 4 of 23 PCP); and 3) a posterolaterally directed regurgitant flow (3 of 13 ACP, 5 of 23 PCP).
On the basis of the 2D findings of the apical bicommissural 2-chamber view, the prolapsed segment was visible in 31 (86.1%; 10 of 13 ACP, 21 of 23 PCP), among whom only 8 (1 ACP, 7 PCP) could be correctly identified by pre-operative TTE, but the concomitant involvement of adjacent scallops of the anterior/posterior MV leaflets was primarily reported instead. Moreover, although MR flow acceleration on the LV side was mostly detected (33 of 36), the sites of acceleration flow alone did not necessarily indicate prolapsed sites. However, some color Doppler patterns were helpful: 1) a V-shaped, double jet flow; 2) an oblique regurgitant flow from its origin toward the anterolateral or posteromedial direction without adhering to the LA wall; and 3) a horizontal regurgitant flow (Figure 1B). These color Doppler patterns have not been reported in A1, P1, A3, or P3 prolapse-related MR. Taken together, the apical bicommissural 2-chamber view is the most helpful for diagnosing commissural MR, especially judged by the combination with 2D and color Doppler flow patterns.
The main findings are as follows: 1) the prolapsed site was more likely to be a posteromedial commissure, confirming earlier studies (3); 2) commissural prolapse was frequently overlooked, and concomitant involvement of adjacent scallops was primarily reported; and 3) the standard imaging planes, especially the apical bicommissural 2-chamber view, can provide unique clues to the presence of commissural MR, for which acceleration flow on the LV side was found in most patients, giving a first impression of the prolapsed site. Color Doppler flow patterns are characteristic (Figure 1B). Therefore, detection of these color Doppler flow patterns at the apical bicommissural 2-chamber view should alert echocardiographers to consider commissural MR, even if 2D findings are not supportive.
Limitations of the study are the relatively small number of patients and its retrospective nature. However, the current work includes the largest population having pure commissural MR with systematic assessment using TTE. Also, delicate selection of the study population strongly supports the TTE findings presented.
In conclusion, commissural MR has distinctive TTE color Doppler flow patterns and can be reliably used for detecting commissural MR.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation