Doppler mapping of postoperative left atrioventricular valve regurgitation

Electrophysiologic and anatomical relationships studied in primum atrioventricular septal defect

Anatomy and pattern of electrical activation predict the function and contraction pattern of the heart. Patients with primum atrioventricular septal defect (primum AVSD) present with abnormality of both anatomical arrangements and electric activation and serve therefore as an interesting population for studying electro-anatomic relationships in the heart. Understanding the relationships between anatomic and electrophysiologic abnormality is appropriate not only for diagnosis, therapy, and prognosis in patients with primum AVSD but also for understanding the developmental relationship between the conduction system and heart structures, in general. This article presents a review of the anatomical and electrophysiologic characteristics of patients with primum AVSD and provides recent knowledge of electroanatomical relationships of the heart.

Surgically created double-orifice left atrioventricular valve: a valve-sparing repair in selected atrioventricular septal defects

OBJECTIVES

Some features of the left atrioventricular valve (large mural leaflet, dystrophic tissue) represent a challenge for repair of atrioventricular septal defects without postoperative regurgitation. A retrospective study was conducted to evaluate the results of surgically creating a double-orifice left atrioventricular valve in such circumstances. Clinical results were analyzed according to valvular and subvalvular left atrioventricular valve measurements in pathologic specimens with atrioventricular septal defects.

METHODS

Among 157 patients operated on for atrioventricular septal defect since October 1989, 10 patients underwent primary repair (n = 8) or reoperation (n = 2) by this procedure. Median age at repair was 3.3 years (0.1-33 years). Anatomic types were complete (n = 3), intermediate (n = 5), and partial (n = 2). Preoperative moderate to severe left atrioventricular valve regurgitation was present in 6 patients. After the repair (two-patch technique in complete atrioventricular septal defect, cleft closed in each case), these 10 patients were found to have moderate to severe residual regurgitation not amenable to repair by annuloplasty. The top edge of the mural leaflet was anchored to the facing free edge of the cleft.

RESULTS

No hospital death or morbidity was observed. Left atrioventricular valve regurgitation was absent or trivial (8 patients) and mild (2 patients). Color-coded echocardiography did not show significant left atrioventricular valve stenosis. The mean diastolic pressure gradient across the left atrioventricular valve was 3.2 +/- 1.1 mm Hg (1.4-4.5 mm Hg). At a median follow-up of 72 months (6-91 months), there was 1 late death, unrelated to left atrioventricular valve malfunction, due to pulmonary vascular obstructive disease. Left atrioventricular valve regurgitation did not increase over time, except in 1 patient in whom regurgitation recently progressed from mild to moderate. At rest, the mean diastolic pressure gradient across the left atrioventricular valve was 3.8 +/- 2.9 mm Hg (1.5-11.2 mm Hg). One child had an early moderate stenosis without pulmonary hypertension. Studies on pathologic specimens (n = 34) indicated that long chordal lengths and large mural leaflet size are essential independent anatomic features to assess its feasibility.

CONCLUSIONS

Surgical creation of a double-orifice left atrioventricular valve is an effective additional procedure for repair of atypical cases of atrioventricular septal defect. The operation may decrease the need for reoperation or left atrioventricular valve replacement.

Three-dimensional echocardiographic analysis of valve anatomy as a determinant of mitral regurgitation after surgery for atrioventricular septal defects

Mitral regurgitation (MR) is a significant complication after atrioventricular septal defect (AVSD) surgery. The relation of the valve leaflet morphology and the MR mechanism remains a conundrum. Two-dimensional echocardiography depicts leaflet edges, whereas volume-rendered 3-dimensional echocardiography provides direct visualization of the surface areas of the mitral valve leaflets. This study examines the relation of mitral valve anatomy as determined by 3-dimensional echocardiography with MR origins in patients after AVSD repair. Twenty-seven patients with AVSD surgery and Doppler color MR were prospectively enrolled (median age was 5 years and 16 patients had Down syndrome). Doppler color flow imaging of the MR jet and 3-dimensional echocardiography of the mitral valve were performed with a probe in the transthoracic or transesophageal position. Enface 3-dimensional views of the mitral valve from the left atrium were reconstructed. Analysis of the 3-dimensional data was possible in 21 of the 27 patients. Mean area ratios of the 3 mitral leaflets were calculated (superior 40 +/- 7%, inferior 35 +/- 5%, mural 25 +/- 6%). Both intra and interobserver variability on the area measurements were <5%. In 12 patients (group 1) the jet appeared to emanate medially from the region of coaptation of the superior and inferior components of the anterior leaflet. In 9 patients (group 2) the jet emanated more laterally from the region toward the mural leaflet. The area ratios of the inferior leaflet were 32 +/- 4% in group 1 and 38 +/- 6% in group 2 (p = 0.02). The area ratios of the mural leaflet were 28 +/- 5% in group 1 and 21 +/- 5% in group 2 (p = 0.007). The superior leaflet area ratio was not different in groups 1 and 2, 40 +/- 9% and 41 +/- 6%, respectively. Three-dimensional echocardiography provides new insight into the anatomic determinants of MR following AVSD surgery.

Predisposing factors of valve regurgitation in complete atrioventricular septal defect

OBJECTIVES

We sought to determine the intrinsic risk factors of valve regurgitation in complete atrioventricular septal defect.

BACKGROUND

Progression of regurgitation varies in each case, although the structure of the common atrioventricular valve itself is a predisposing factor.

METHODS

In 90 consecutive patients undergoing surgical repair, we evaluated the preoperative and postoperative regurgitation, valve morphology, age at surgery and associated anomalies. A regurgitation jet with a high velocity reaching the deep left atrial wall by echocardiography was estimated as marked regurgitation.

RESULTS

None of the 40 patients with Rastelli type C and an undivided inferior bridging leaflet had preoperative regurgitation in the first year of life, and 12% of them (95% confidence intervals [CI]: 0% to 28%) showed regurgitation at the age of 2. Of the remaining 50 with Rastelli type A and/or a divided inferior leaflet, regurgitation was determined in 21% (95% CI: 6% to 35%) of those 1 year old and in 49% (95% CI: 29%7 to 69%) of those 2 years old (p < 0.01). All patients underwent corrective surgery using the double-patch technique, with the "cleft" being sutured adequately. Irrespective of the valve morphology, regurgitation remained in 52% (12 of 23) of those with preoperative regurgitation, whereas regurgitation developed postoperatively in 28% (16 of 58) of those without regurgitation (p < 0.001).

CONCLUSIONS

Those with Rastelli type C and an undivided inferior leaflet had a lesser degree of progression of preoperative regurgitation. However, regurgitation was likely to exist even after adequate repair once regurgitation had already advanced. Therefore, early primary repair before progression of the regurgitation may be the key to maintaining better competence of the atrioventricular valve.

Comparison of cleft and papillary muscle position in cleft mitral valve and atrioventricular septal defect

Differentiation of cleft mitral valve from atrioventricular septal defect (AVSD) is surgically important because of different conduction pathways. The purpose of this study was to find echocardiographic markers for differentiating cleft mitral valve from AVSD. We examined 11 children with cleft mitral valve, 11 children with AVSD, and 11 normal children. We defined a fixed reference point (0 degrees of arc) at the medial junction of the right ventricular free wall with the posteroinferior ventricular septum. Left ventricular papillary muscle and cleft position was measured clockwise in degrees of arc from 0 degrees around a point representing the center of the left ventricle in the parasternal short-axis views. Mural leaflet size was expressed by the arc between the bases of the papillary muscles. Papillary muscle position in cleft mitral valve was similar to that in normals (anterolateral ventricular papillary muscle:cleft mitral valve 194 +/- 10 degrees, normals 191 +/- 8 degrees; posteromedial ventricular papillary muscle:cleft mitral valve 329 +/- 10 degrees, normals 329 +/- 14 degrees). In AVSD, both left ventricular papillary muscles originated closer to each other and were rotated counterclockwise (anterolateral papillary muscle: 182 +/- 7 degrees; posteromedial papillary muscle: 287 degrees +/- 17 degrees). The mural leaflet size was similar in cleft mitral valve and in normal children. In AVSD, the mural leaflet was significantly smaller than in cleft mitral valve and in normals. The cleft position did not permit distinction between cleft mitral valve and AVSD. In conclusion, echocardiographic measurements of papillary muscle position and mural leaflet size permit differentiation of cleft mitral valve from AVSD.

Limitations of color flow Doppler imaging in the quantification of valvular regurgitation: velocity of regurgitant jet, rather than volume, determines size of color Doppler image

The objective of this study was to determine the validity of estimation of regurgitant volume by visual assessment of color flow Doppler display. An experimental apparatus was designed that is capable of ejecting precise volumes of echogenic material from one chamber to another under continuous color flow Doppler monitoring. The velocity of flow was altered independently by changing either the size of the orifice through which flow occurred or the ejection rate. In this manner the differential effects of volume and velocity on the color flow Doppler image could be examined. The maximum area encompassed by the color flow Doppler pattern for each ejection was planimetered by using commercially available on-line software. In addition the reviewer in each case applied a subjective grade to the appearance of the color flow jet (1+ to 4+). Comparison was then made of the color flow Doppler appearance of equal volumes flowing at different velocities and of different volumes flowing at different velocities. In the initial series a solution of agitated hetasarch was used. When equal volumes were imaged at different velocities the higher-velocity jet appeared larger, both subjectively (3+ vs 1+) and by measuring the area encompassed in the Doppler flow profile (40.3 +/- 1.8 vs 22.0 +/- 1.4 cm2, p = 0.0001). Furthermore, when different volumes were imaged at different velocities, the smaller volume (3 ml vs 6 ml) appeared larger when it was flowing at higher velocity (3+ vs 2+, 40.3 +/- 1.8 vs 32.4 +/- 1.3 cm2, p = 0.0006). These experiments were repeated with blood, confirming the results of the initial study.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative evaluation of atrioventricular septal defect repair by color flow mapping echocardiography

Despite improving survival rates after repair of atrioventricular septal defect, many patients require reoperation because of postoperative heart failure. We used intraoperative color flow mapping echocardiography to assess the results of surgical repair of atrioventricular septal defect in 19 consecutive patients and compared those findings with results three to five days and 3 to 11 months after repair. There was close correlation between intraoperative and postoperative color flow mapping echocardiography in estimating the presence and severity of left atrioventricular valve regurgitation. All patients survived surgical repair, but in 4 (21%), postoperative congestive heart failure due to left atrioventricular valve regurgitation developed. The need for reoperation was significantly correlated with the severity of left atrioventricular valve regurgitation (r = 0.68) as estimated by intraoperative echocardiography and preoperative aberrancies in the atrioventricular valve (r = 0.68). Age, weight, additional congenital heart disease, preoperative pulmonary vascular resistance, preoperative atrioventricular valve regurgitation, and postoperative mean pulmonary arterial or left atrial pressure were not significantly correlated with the need for reoperation. Intraoperative color flow mapping echocardiography can accurately predict the development of early postoperative heart failure and subsequent reoperation after surgical repair of atrioventricular septal defect.