Patients

Preoperative two-dimensional echocardiograms from 166 patients with AR grade ≥ 2 referred for valve-sparing aortic root reconstruction to the Cardio-Thoracic Surgery Department of Leiden University Medical Center from 2001 to 2014 were evaluated. Patients with acute endocarditis, connective tissue disease, insufficient image quality, organic MR, or mitral stenosis were excluded ( Figure 1 ).

Flowchart of patient inclusion.

Clinical characteristics were prospectively collected in the departmental cardiology information system (EPD-Vision; Leiden University Medical Center, Leiden, The Netherlands) and retrospectively analyzed. Mitral valve geometry, MR grade, AR grade, and LV volumes and function were analyzed. Mitral valve geometry was compared between patients with moderate or severe secondary MR and patients without.

The institutional review board approved this retrospective analysis of clinically acquired data and waived the need for patient written informed consent.

Two-Dimensional Transthoracic Echocardiography

Transthoracic echocardiography was performed preoperatively using commercially available ultrasound systems (System Five, Vivid 7, and Vivid E9; GE Vingmed Ultrasound AS, Horten, Norway) equipped with 3.5-MHz or M5S transducers. Parasternal, apical, subcostal, and suprasternal views were obtained at rest with patients in the left decubitus position. Two-dimensional and Doppler data were acquired according to current recommendations. The echocardiographic data were digitally stored in cine-loop format, and data were retrospectively analyzed using commercially available software (EchoPAC version 112.0.1; GE Vingmed Ultrasound AS).

AR grade was assessed using a multiparametric approach including the measurement of the jet width relative to the LV outflow tract (LVOT) width and the vena contracta in the parasternal and apical views. AR was graded as grade 2 (mild to moderate; jet width/LVOT width ratio of 0.25–0.45 and/or vena contracta of 3.0–4.5 mm), grade 3 (moderate to severe; jet width/LVOT width ratio of 0.46–0.64 and/or vena contracta of 4.6–5.9 mm), or grade 4 (severe; jet width/LVOT width ratio ≥ 0.65 and/or vena contracta ≥ 6.0 mm). The severity of secondary MR was quantitatively determined by the proximal isovelocity surface area method or by measuring the vena contracta in the parasternal long-axis view, according to current recommendations. MR was graded as absent when there was no regurgitant jet. Among patients with regurgitant jets, the proximal isovelocity surface area method could be performed in 45 patients. In the remaining 33 patients, vena contracta measurement in the parasternal long-axis view was used to classify MR. Secondary MR was defined as mild (regurgitant volume < 15 mL or vena contracta of 0.1 to 2.9 mm), moderate (regurgitant volume of 15 to 29 mL or vena contracta of 3 to 6.9 mm), or severe (regurgitant volume ≥ 30 mL or vena contracta ≥ 7 mm).

Mitral valve geometry was assessed in the parasternal long-axis view ( Figure 2 ). Retrospectively, the images were zoomed in on the mitral valve. The measurements were performed by two independent observers, and values were averaged. The length of coaptation between the anterior and posterior mitral leaflets (coaptation length), the distance between the annular plane and the coaptation point (coaptation height), and the area enclosed between the annular line and the mitral leaflets (tenting area) were measured in mid-systole. Anterior and posterior mitral leaflet length was measured in mid-diastole. The parasternal short-axis view was used to measure the end-diastolic inter–papillary muscle distance. The mitral annulus was measured at end-systole in the apical views. The anterior-posterior diameter and intercommissural diameter were obtained from the apical four- and two-chamber views, respectively.

Measurements of mitral valve geometry. During mid-diastole: mitral valve leaflet length (A) of the anterior mitral leaflet and the posterior mitral leaflet. At mid-systole: coaptation length (B) , coaptation height (C) , and tenting area (D) .

Left atrial volume, LV end-diastolic volume, and LV end-systolic volume were measured in the apical two- and four-chamber views and indexed to body surface area (left atrial volume index [LAVi], LV end-diastolic volume index, and LV end-systolic volume index [LVESVi]). Sphericity index was calculated by dividing the length by the width of the left ventricle in the apical four-chamber view, as previously described. LV ejection fraction (LVEF) was calculated according to Simpson’s biplane method.

Surgery

After medial sternotomy, cardiopulmonary bypass was set through cannulation of the distal ascending aorta or the subclavian or femoral artery (in patients with ascending aortic pathology). The aorta was incised at the level of the pulmonary artery and resected until the sinotubular junction.

Intraoperatively, the surgeon decided whether valve-sparing aortic root reconstruction was feasible. In these patients, either the sinotubular junction was restored using a vascular graft or the native sinuses of Valsalva were resected, a graft was implanted using the reimplantation technique (modified David procedure), or the remodeling technique (Yacoub procedure) and the coronary buttons were reimplanted. Otherwise, aortic valve and root replacement using the Medtronic Freestyle stentless bioprosthesis (Medtronic, Minneapolis, MN) was performed. In these patients, the coronary buttons were mobilized, and the aortic root and valve were completely excised. The bioprosthesis was then implanted, usually with 120° clockwise rotation, with interrupted sutures at one plane at the level of the nadir of the sinus. Thereafter, the coronary buttons were reattached to the bioprosthesis.

If secondary MR was present, concomitant mitral valve surgery was performed at the discretion of the surgeon. In all patients in whom concomitant mitral valve surgery was performed, restrictive ring annuloplasty was used to repair the mitral valve. No mitral valve replacements were performed.

Statistical Analysis

All data analyses were performed using SPSS version 20.0 (IBM, Armonk, NY). Continuous variables are reported as mean ± SD or as medians and interquartile ranges, as appropriate. Categorical variables are reported as counts and percentages. Patients with no or mild MR (grade < 2) were compared with patients with moderate or severe MR (grade ≥ 2). Continuous and categorical variables were compared by using the Student t test (or the Mann-Whitney U test for variables not normally distributed) and the χ ² test, respectively. Mitral valve geometric changes were compared between patients with normal left ventricles (LVESVi < 31 mL/m ² ) and patients with dilated left ventricles (LVESVi ≥ 31 mL/m ² ). Multivariate logistic regression analysis was performed to investigate the independent associates of significant (moderate or severe) secondary MR. All echocardiographic variables with P values < .05 on univariate logistic regression analysis were included in the multivariate model. The odds ratio and 95% confidence interval were calculated. All statistical tests were two sided. P values < .05 were considered to indicate statistical significance. Interobserver and intraobserver variability of mitral valve geometry measurements was evaluated using Bland-Altman analysis in 40 randomly selected patients. Furthermore, the coefficients of variation were calculated for coaptation length, coaptation height, and tenting area.

Surgical Characteristics

Patients with moderate or severe secondary MR had higher European System for Cardiac Operative Risk Evaluation II scores (median, 3.6% [interquartile range, 2.5%–7.8%] vs 2.4% [interquartile range, 1.6%–4.5%]; P = .003) compared with their counterparts. Seventy-three patients (61%) underwent valve-sparing aortic root reconstruction. The remaining 47 patients (39%) were considered ineligible for repair during surgery and underwent aortic valve and root replacement using the Medtronic Freestyle stentless bioprosthesis.

Concomitant coronary artery bypass grafting was performed in 25 patients (21%). Concomitant mitral valve surgery with restrictive ring mitral annuloplasty was performed in 13 patients (11%). Concomitant tricuspid valve surgery (annuloplasty) was performed in 10 patients (8%).

Echocardiographic Measurements Associated with Preoperative Secondary MR

The preoperative echocardiographic data are presented in Table 2 . LV volumes and mitral valve geometric measurements in the parasternal long-axis view were available in all 120 patients, whereas inter–papillary muscle distance and LAVi were available in 108 and 119 patients, respectively. Coaptation length, coaptation height, and the lengths of the anterior and posterior leaflets were comparable in both groups. Patients with moderate or severe secondary MR had larger tenting areas (1.59 ± 0.79 vs 1.25 ± 0.41 cm ² , P = .003) and larger inter–papillary muscle distances (28.4 ± 9.5 vs 24.8 ± 5.2 mm, P = .014) compared with those without significant secondary MR. There was a tendency toward larger mitral annular diameters among patients with MR grade ≥ 2. LV end-diastolic volume index was comparable between patients with and without secondary MR, whereas LVESVi was slightly larger (nonsignificant) in patients with moderate or severe secondary MR. Consequently, the LVEF was significantly lower in patients with moderate or severe secondary MR (47.3 ± 12.2% vs 54.3 ± 9.3%, P = .002).

Table 2

Preoperative echocardiographic characteristics

Variable	Non-significant secondary MR	Significant secondary MR	P
	( n = 92)	( n = 28)
Anterior leaflet length (mm)	24.6 ± 4.1	24.6 ± 4.1	.970
Posterior leaflet length (mm)	18.3 ± 3.2	18.9 ± 3.6	.383
Coaptation length (mm)	7.8 ± 1.7	7.3 ± 1.9	.273
Coaptation height (mm)	8.0 ± 2.3	8.5 ± 2.6	.287
Tenting area (cm 2 )	1.25 ± 0.41	1.59 ± 0.79	.003
Inter–papillary muscle distance (mm)	24.8 ± 5.2	28.4 ± 9.5	.014
Mitral annular AP diameter (mm)	31.0 ± 4.9	33.1 ± 6.0	.068
Mitral annular intercommissural diameter (mm)	31.4 ± 5.2	33.5 ± 5.6	.068
LAVi (mL/m 2 )	32.0 ± 12.2	40.9 ± 13.7	.002
LVEDVi (mL/m 2 )	77.4 ± 27.9	79.6 ± 28.9	.715
LVESVi (mL/m 2 )	36.1 ± 17.5	42.8 ± 23.9	.104
Sphericity index	1.59 ± 0.27	1.59 ± 0.25	.949
LVEF (%)	54.3 ± 9.3	47.3 ± 12.2	.002

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