Semiquantitation of aortic regurgitation by different Doppler echocardiographic techniques and comparison with ultrafast computed tomography

Results of valve-sparing aortic root reconstruction in 158 consecutive patients

BACKGROUND

This study assesses the durability and clinical outcome of valve-sparing aortic root reconstruction using the reimplantation technique in a single center cohort.

METHODS

From July 1993 to July 2001, 158 patients underwent replacement of the ascending aorta with native valve reimplantation. Mean age of patients was 52 +/- 17 years (9 to 84 years), 103 were men (65%). Thirty-four patients (22%) suffered from Marfan's syndrome. Aortic dissection Stanford type A was present in 29 patients (19%) (22 acute, 7 chronic), and concomitant partial or total arch replacement was necessary in 57 patients (36%). One or more additional procedures were performed in 28 patients (18%). Mean follow-up was 36 +/- 25 months (0.4 to 96 months).

RESULTS

Thirty-day mortality was 3.8% (6 patients), but only 2.2% in elective patients. Mean bypass time was 169 +/- 50 minutes (99 to 440 minutes), aortic cross-clamp time was 129 +/- 31 minutes (79 to 205 minutes). In patients undergoing arch replacement, circulatory arrest was 26 +/- 18 minutes (7 to 99 minutes). During follow-up, there were 5 (3.3%) cardiac-related late deaths. Grade of aortic insufficiency (AI) decreased from 2.3 +/- 1.1 (0 to 4) preoperatively to 0.23 +/- 0.44 (0 to 2) postoperatively (p < 0.0001). Six patients required aortic valve replacement, 4 of those due to progressive AI. Average grade of AI increased significantly to 0.42 +/- 0.61 (0 to 3) at latest evaluation (p = 0.002). Two patients experienced a transient ischemic attack within the first postoperative week. No further thromboembolic complications were noticed. All patients presented with a favorable exercise tolerance.

CONCLUSIONS

The aortic valve reimplantation technique achieves excellent clinical outcome with few complications even in complex pathologies. Lack of anticoagulation and favorable durability encourage wider and earlier use of this technique.

Aortic valve reimplantation in ascending aortic aneurysm: risk factors for early valve failure

BACKGROUND

Aortic root reconstruction by reimplantation of the native valve represents a new therapeutic option for ascending aortic aneurysms. Information about long-term follow-up is limited, and possible predictors for failure of reconstruction have not been evaluated so far.

METHODS

After aortic valve reimplantation 101 patients were followed in a prospective observational study. From this cohort the first 75 consecutive patients with a complete 1-year follow-up were chosen for further analysis. Clinical and echocardiographic data were obtained preoperatively, intraoperatively, and early postoperatively, as well as after 1 year of follow-up.

RESULTS

No mortality was observed within the first 30 days. There were 52 male patients, mean age was 49.1+/-20.6 years, observation period was 35.6+/-20.6 months, and Marfan's syndrome was present in 22 patients. Although in 67 patients a stable valve function could be demonstrated, 5 patients presented with mild aortic insufficiency or had to be operated on again for secondary valve failure (n = 3). Analyzing possible demographic, disease-related, and procedure-related risk factors in a multivariable approach, only level of coaptation within the graft (as assessed by echocardiography) could be identified as being related to the subsequent development of aortic insufficiency. Coaptation level within the tube graft (type A) resulted in a mean aortic regurgitation grade of 0.3+/-0.5 as compared with a mean grade of 2.5+/-0.6 for a coaptation type C (below the prosthesis; p < 0.001).

CONCLUSIONS

Aortic valve reimplantation is a promising alternative to alloprosthetic composite replacement. A level of coaptation within the tube graft is essential to achieve valve competence.

Aortic and mitral regurgitation: quantification using moving slice velocity mapping

Comprehensive assessment of the severity of valvular insufficiency includes quantification of regurgitant volumes. Previous methods lack reliable slice positioning with respect to the valve and are prone to velocity offsets due to through-plane motion of the valvular plane of the heart. Recently, the moving slice velocity mapping technique was proposed. In this study, the technique was applied for quantification of mitral and aortic regurgitation. Time-efficient navigator-based respiratory artifact suppression was achieved by implementing a prospective k-space reordering scheme in conjunction with slice position correction. Twelve patients with aortic insufficiency and three patients with mitral insufficiency were studied. Aortic regurgitant volumes were calculated from diastolic velocities mapped with a moving slice 5 mm distal to the aortic valve annulus. Mitral regurgitant flow was indirectly assessed by measuring mitral inflow at the level of the mitral annulus and net aortic outflow. Regurgitant fractions, derived from velocity data corrected for through-plane motion, were compared to data without correction for through-plane motion. In patients with mild and moderate aortic regurgitation, regurgitant fractions differed by 60% and 15%, on average, when comparing corrected and uncorrected data, respectively. Differences in severe aortic regurgitation were less (7%). Due to the large orifice area of the mitral valve, differences were still substantial in moderate-to-severe mitral regurgitation (19%). The moving slice velocity mapping technique was successfully applied in patients with aortic and mitral regurgitation. The importance of correction for valvular through-plane motion is demonstrated.

Valve-preserving operation in acute aortic dissection type A

BACKGROUND

The standard treatment in patients with acute aortic dissection type A (AADA) and aortic regurgitation is either supracommissural aortic or composite replacement of ascending aorta and valve. Valve-preserving surgical procedures provide a promising alternative. We retrospectively analyzed midterm results after these different approaches.

METHODS

From October 1995 to December 1999, 52 patients (35 men, 17 women) underwent repair of AADA. Patient ages ranged from 30 to 83 years. Composite replacement was chosen for degenerated aortic valves or prior valve replacement (group A; n = 8). With normal root diameter, supracommissural replacement of the ascending aorta was performed (group B; n = 22). For preexisting root dilatation the aortic root was either remodeled (root diameter 30 to 50 mm, group C; n = 17) or the valve reimplanted within a vascular graft (root diameter more than 50 mm, group D; n = 5).

RESULTS

All patients underwent either proximal (n = 46) or total (n = 6) arch replacement under circulatory arrest. Eight patients (15.4%) died (group A: n = 3; group B: n = 3; group C: n = 2). Freedom from aortic regurgitation of grade 2 or more at 2 years was 100% in groups A and D, 90.9% in group C, and 75% following supracommissural replacement. At 2 years freedom from proximal reoperation was 100% in groups A, C, and D and 84.5% in group B.

CONCLUSIONS

In AADA valve-preserving root replacement leads to improved stability of aortic valve function without an increased operative risk. Midterm results are promising and may show further superiority over supracommissural aortic replacement in the future.

Comparison of aortic valve gradient during exercise after aortic valve reconstruction

PURPOSE

Aortic valve preservation is a promising alternative to conventional composite replacement of aortic valve and ascending aorta. This approach may have a physiologic benefit compared with valve replacement similar to that seen in mitral valve reconstruction. We investigated aortic valve gradients at rest and during exercise in patients who had undergone valve-preserving aortic replacement and compared them with composite replacement of valve and aorta.

METHODS

Four groups were studied: nine patients underwent composite valve replacement (group A: valve diameter, 23 to 27 mm), eight patients underwent remodeling of the aortic root (group B), and another nine patients had reimplantation of the aortic valve (group C). Healthy volunteers were studied as a control group (group D). Using continuous-wave Doppler echocardiography, all patients were examined on a bicycle ergometer for aortic valve gradients (0 to 75 W).

RESULTS

There were no differences among the groups with respect to age, body surface, left ventricular end-diastolic diameter, fractional shortening, or left ventricular mass. Maximum resting gradients were significantly elevated in group A compared with groups B, C, and D (group A: 21.3 +/- 7.1 mm Hg; group B: 9.0 +/- 4.5 mm Hg; group C: 8.6 +/- 3.7 mm Hg; group D: 4.9 +/- 1.6 mm Hg; p < 0.05). At 75 W, group A exhibited significantly higher gradients than all other groups (group A: 31.3 +/- 7.5 mm Hg; group B: 13.9 +/- 6.6 mm Hg; group C: 12.8 +/- 3.5 mm Hg; group D: 9. 2 +/- 1.9 mm Hg; p < 0.05). There was no significant difference among the other groups. Both valve-preserving groups had only insignificantly higher gradients than the control group.

CONCLUSION

Our data strongly support the suggestion that preserving the aortic valve restores nearly normal hemodynamic function of the aortic valve. Long-term observations will have to prove the clinical relevance of restoring physiologic aortic valve hemodynamics.

Contemporary cardiac imaging: an overview

Comprehensive cardiac assessment embraces virtually every imaging modality and includes information about coronary vascular anatomy as well as cardiac morphology, function, perfusion, metabolism, and tissue characterization. Through sophisticated computer processing and image analysis, newer imaging technologies such as computed tomography (CT), magnetic resonance (MR), MR spectroscopy, and positron emission tomography now provide quantitative information that may obviate more invasive angiographic assessment. Currently, no single imaging technology realizes all questions relating to cardiac form and function, and many of the technologies overlap in the content and quality of information they provide. This overview seeks to provide a broad perspective on current cardiac imaging, articulating the benefits of various technologies and their limitations.

Strategy for optimal aortic regurgitation quantification by Doppler echocardiography: agreement among different methods

BACKGROUND

Although different Doppler methods have been validated for aortic regurgitation quantification, the benefit of combining information from different methods has not been defined.

METHODS

Our study included 2 phases. In the initial phase (60 patients), Doppler parameters (jet width, short-axis jet area, apical jet area, regurgitant fraction from pulmonary and mitral flow, and deceleration slope) were correlated with angiography; range values for each severity grade were defined and intraobserver and interobserver and intermachine variability were studied. In the validation phase (158 patients), defined value ranges were prospectively tested and a strategy based on considering as the definitive severity grade that in which the two best methods agreed was tested.

RESULTS

Jet width had the best correlation with angiography (r = 0.91), and its ratio with the left ventricular outflow diameter did not improve the correlation (r = 0.85) and decreased reproducibility. Apical jet area and regurgitant fraction from pulmonary flow permitted acceptable quantification (r = 0.87 and 0.86, respectively) but with worse reproducibility. The other methods were not assessable in 20% to 30% of studies. Concordance with angiography decreased in jet width when the jet was eccentric (90% vs 77%, P <.01), in apical jet area when mitral valve disease was present (84% vs 65%, P <.02), and in short-axis jet area and regurgitant fraction from pulmonary flow with concomitant aortic stenosis (77% vs 44%, P <.002 and 77% vs 53%, P <.02, respectively). Agreement with angiography was very high (94 [95%] of 99) when severity grade coincided in both jet width and apical jet area. In 59 cases without concordance, regurgitant fraction from pulmonary flow was used as a third method. Overall, this strategy permitted concordance with angiography in 146 patients (92%).

CONCLUSIONS

Jet width is the best predictor in aortic regurgitation quantification by Doppler echocardiography. However, better results were obtained when a strategy based on concordance between jet width and another Doppler method was established, particularly when the jet was eccentric.

Heart motion adapted cine phase-contrast flow measurements through the aortic valve

A method for magnetic resonance cine velocity mapping through heart valves with adaptation of both slice offset and angulation according to the motion of the valvular plane of the heart is presented. By means of a subtractive labeling technique, basal myocardial markers are obtained and automatically extracted for quantification of heart motion at the valvular level. The captured excursion of the basal plane is used to calculate the slice offset and angulation of each required time frame for cine velocity mapping. Through-plane velocity offsets are corrected by subtracting velocities introduced by basal plane motion from the measured velocities. For evaluation of the method, flow measurements downstream from the aortic valve were performed both with and without slice adaptation in 11 healthy volunteers and in four patients with aortic regurgitation. Maximum through-plane motion at the aortic root level as calculated from the labeled markers averaged 8.9 mm in the volunteers and 6.5 mm in the patients. The left coronary root was visible in 2-4 (mean: 2.2) time frames during early diastole when imaging with a spatially fixed slice. Time frames obtained with slice adaptation did not contain the coronary roots. Motion correction increased the apparent regurgitant volume by 5.7 +/- 0.4 ml for patients with clinical aortic regurgitation, for an increase of approximately 50%. The proposed method provides flow measurements with correction for through-plane motion perpendicular to the aortic root between the valvular annulus and the coronary ostia throughout the cardiac cycle. Magn Reson Med 42:970-978, 1999.

Replacement of ascending aorta with aortic valve reimplantation: midterm results

OBJECTIVE

Aneurysms of the aortic root lead to aortic valve incompetence due to dilatation of the sinotubular junction and annuloaortic ectasia. Reimplantation of the native, structurally intact aortic valve within a Dacron tube graft corrects annular ectasia as well as dilatation of sinotubular junction and aortic sinuses. Durability of this valve repair with respect to increased mechanical stress on valve cusps is discussed controversially and is yet unknown.

METHODS

Since 7/93, replacement of the ascending aorta with repair of the aortic valve was performed in 48 patients (34 male, 14 female; 47+/-20 years) with aortic insufficiency and aneurysm of the aortic root. Fifteen patients (31%) had Marfan's syndrome and five patients (10%) had an aortic dissection type A (two acute, three chronic). In 11 patients (23%), concomitant replacement of the aortic arch was necessary utilizing elephant trunk technique in two patients. Additionally, one patient required mitral valve repair and two other patients coronary artery bypass grafts. Clinical and echocardiographic follow-up was performed in 6-12 month intervals for a cumulative study period of 100 patient years.

RESULTS

There were no operative deaths. Two patients (4%) died 5 and 20 months postoperatively. One additional patient experienced a TIA within the first postoperative week. Three patients (6%) with an early postoperative aortic insufficiency (AI) > 1 required aortic valve replacement after 9, 11, and 14 months due to progressive AI. In these patients, distortion of the aortic root geometry led to valve incompetence. All other patients have no or mild aortic insufficiency. The repair now remains stable for up to 63 months (mean 25+/-18 months). Other valve related complications did not occur.

CONCLUSIONS

Our results demonstrate that this type of aortic valve repair achieves excellent results in selected patients. Perfect coaptation of valve cusps during the repair with no or only trace AI at initial echocardiography seems to be essential for durability.

An integrated approach to the quantification of aortic regurgitation by Doppler echocardiography

BACKGROUND

Although different Doppler methods have been proposed for the quantification of aortic regurgitation, no study has prospectively compared these methods with each other and their correlation with angiography. The aim of this study was to prospectively analyze the usefulness of different Doppler echocardiography parameters by testing all such parameters in each patient.

METHODS

Fifty-one patients with aortic regurgitation underwent 2-dimensional and Doppler echocardiographic studies and catheterization. The following Doppler indexes were analyzed and compared with aortography. Color Doppler: (1) jet color height/left ventricular outflow tract height in parasternal long-axis view, and (2) jet color area/left ventricular outflow tract area in short-axis view. Continuous Doppler: (3) regurgitant flow pressure half-time, (4) regurgitant flow time velocity integral (in centimeters), and (5) regurgitant flow time velocity integral (in centimeters)/diastolic period (in milliseconds). Pulsed Doppler in thoracic and abdominal aorta: (6) time velocity integral of diastolic reverse flow (in centimeters), (7) time velocity integral of systolic anterograde flow/integral of diastolic reverse flow, (8) (time velocity integral of diastolic reverse flow/diastolic period) x 100, and (9) diastolic reverse flow duration/diastolic period (as a percentage). We compared these parameters with severity of regurgitation measured by angiography and classified as mild, moderate, or severe.

RESULTS

The most useful parameters were (1) jet color height/left ventricular outflow tract height (correctly classified 42 of 49 patients), (2) (time velocity integral of diastolic reverse flow/diastolic period) x 100 in the thoracic aorta (correctly classified 41 of 46 patients), and (3) (time velocity integral of diastolic reverse flow/diastolic period) x 100 in the abdominal aorta (correctly classified 42 of 49 patients). Sequential integration of these 3 parameters correctly classified 96% of patients (44 of 46 patients) and was achieved in 90% of cases.

CONCLUSION

An integrated combination of several Doppler parameters can quickly and accurately classify the degree of aortic regurgitation as determined by angiography.

Balloon dilation of severe aortic stenosis in the neonate: comparison of anterograde and retrograde catheter approaches

OBJECTIVES

We sought to compare anterograde and retrograde balloon dilation of severe aortic valve stenosis in neonates.

BACKGROUND

There is a high incidence of iliofemoral artery complications after retrograde balloon dilation of the aortic valve in the neonate. Therefore, a nonarterial technique of catheter access to the aortic valve would be worth exploring.

METHODS

Group 1 included 11 consecutive patients (median age 6 days, range 1 to 42; median weight 3.5 kg, range 2.16 to 4.25) undergoing attempted anterograde dilation through a femoral venous approach. Group 2 included 15 patients (median age 3 days, range 1 to 35; median weight 3.4 kg, range 2.5 to 4.4 kg) who underwent attempted retrograde dilation, including 2 in whom attempted anterograde approach had failed.

RESULTS

The valve was successfully crossed in 9 of 11 anterograde and 13 of 15 retrograde dilations. In both groups, the peak gradient across the valve decreased significantly (both p = 0.001). On echocardiography, the jet width of the aortic incompetence/ annulus diameter ratio was 0.16 +/- 0.08 (mean +/- SD) after anterograde and 0.51 +/- 0.24 after retrograde dilation (p = 0.03), possibly because of unrecognized valve leaflet perforation. Two patients in group 1 developed persistent, mild mitral insufficiency. Femoral artery thrombosis developed in one patient after anterograde dilation and in eight after retrograde dilation (p = 0.03).

CONCLUSIONS

This series demonstrates that an anterograde approach for balloon angioplasty of severe neonatal aortic valve stenosis is feasible, achieves good hemodynamic relief and lessens morbidity compared with retrograde arterial techniques.

Transesophageal echocardiography

This article presents an overview of the benefits and efficacy of transesophageal echocardiography (TEE) in the critically ill patient. The echocardiographic evaluation of ventricular function both regional and global, is discussed with special emphasis on ischemic heart disease; assessment of preload, interrogation of valvular heart disease (prosthetic and native) and its complications; endocarditis and its complications; intracardiac and extracardiac masses, including pulmonary embolism; aortic diseases (e.g., aneurysan, dissection, and traumatic tears); evaluation of patent foramen ovale and its association with central and peripheral embolic events; advancements in computer technology; and finally, the effect of TEE on critical care.

Aortic valve regurgitation after surgical versus percutaneous balloon valvotomy for congenital aortic valve stenosis

To compare characteristics of aortic regurgitation (AR), the results of 213 procedures (110 balloon aortic valvotomies [BAV] and 103 surgical aortic valvotomies [SAV]) for treatment of congenital aortic valve stenosis were reviewed. These procedures were performed in 187 patients from June 1981 to September 1993. Echocardiograms recorded immediately before, within 6 months afterward, and at latest follow-up were compared. Color Doppler was used to assess the degree of AR and was quantified as the ratio of the regurgitant jet width to valve annulus, the jet width ratio. Whereas BAV patients were older (median age 5.7 years vs 3 months; p = 0.0001), there was no significant difference in median follow-up interval (3.1 years [range 0.5 to 7.2] for BAV vs 3.6 years [range 0.6 to 10.4] for SAV; p = 0.44). The mean balloon-to-annulus ratio for BAV was 0.99 +/- 0.09. An open valvotomy was performed in 83% of surgical cases. Acute systolic gradient reduction and subsequent increase at late follow-up was similar for both groups. Acutely, the mean jet width ratio increased similarly (p = 0.84) for BAV (+9 +/- 15%; p = 0.0001) and SAV (+9 +/- 12%; p = 0.0003) and was not related to age at procedure. At late follow-up, mean jet width ratio further increased significantly in both groups, although there was no difference (p = 0.17) in amount of progression (BAV +10 +/- 12%; p = 0.0001, SAV +15 +/- 13%; p = 0.0002). Thus, BAV and SAV produce AR of similar severity with similar rates of progression.

Quantitative dynamics of left ventricular emptying and filling as a function of heart size and stroke volume in pure aortic regurgitation and in normal subjects

Quantitative understanding of the dynamics of left ventricular (LV) emptying and filling as the left ventricle dilates but maintains ejection fraction is limited. Cine computed tomography was used to quantify peak LV emptying and filling characteristics in 30 patients with normal ejection fraction but variable end-diastolic and stroke volumes. Group I consisted of 15 normal male patients and group II of 15 male patients with chronic, well-compensated, isolated aortic regurgitation. For each patient global LV volumes, absolute peak emptying and peak early diastolic filling rates and the timing of these maximal slopes were quantified. Mean arterial pressure and heart rate were within the normal range and ejection fraction and ages similar between groups I and II. Between-group analyses showed significantly increased end-diastolic and stroke volumes in group II compared with group I but nearly identical end-systolic volumes. Likewise, absolute peak emptying and filling rates were significantly greater in group II than in group I patients. The ratio of peak emptying rate to peak filling rate remained constant between groups. Timing of peak emptying and filling were similar in both groups. Absolute LV peak emptying and filling rates were found to vary linearly with end-diastolic and stroke volumes in all subjects examined. However, referencing peak emptying or peak filling rates to end-diastolic or total stroke volumes eliminated intergroup differences. Thus, in the presence of preserved ejection fraction and normal arterial pressure, the dynamic rates of LV emptying and early diastolic filling increase in direct proportion to absolute end-diastolic and stroke volumes, but the ratio of peak emptying to peak filling rate remains constant.