Leaflet Mobility Research Articles

Mitral valve replacement with complete retention of native leaflets

Although both mitral leaflets contribute equally to the preservation of left ventricular function after mitral valve replacement, most surgeons routinely excise the anterior mitral leaflet. Possible disadvantages of leaflet retention are left ventricular outflow tract obstruction and interference with prosthetic valve motion. In 31 patients undergoing mitral valve replacement, all mitral valvular and subvalvular tissue was completely retained using a technique that involved reefing the native leaflets into the valve sutures. Fifteen Carpentier-Edwards porcine and 16 St. Jude Medical valves were implanted. Two patients died of causes unrelated to this technique. In the others, echocardiography demonstrated either no or an insignificant left ventricular outflow tract gradient, and, in most, no valvular tissue could be seen in the left ventricular outflow tract. No interference with prosthetic leaflet mobility occurred. The salutary results of mitral valve replacement with complete leaflet retention recommend its use.

Severe calcification does not affect long-term outcome of mitral valve repair

Some surgeons have suggested that the presence of severe calcification in the mitral valve annulus or leaflets precludes successful repair. Our institution has attempted to repair these calcified valves when good annular and leaflet mobility could be achieved by annular debridement and leaflet resection. From June 1979 through June 1993 558 mitral valve repairs were performed using Carpentier's techniques. When calcified valves were encountered, these techniques were modified to include annular debridement and mechanical leaflet decalcification. Calcification was identified preoperatively in 49 patients (8.8%) by either left ventricular fluoroscopy or echocardiography and was debrided in 64 patients (11.5%). This included 24 annular debridements, 28 leaflet debridements, and 12 annular and leaflet debridements. Patient ages ranged from 13 to 83 years (mean age, 62.3 years), and 25 patients (39.1%, 25 / 64 ) had concomitant cardiac procedures. Operative mortality was 6.2% ( 4 / 64 ) overall and 2.6% ( 1 / 39 ) for isolated mitral valve repairs. Calcium debridement was performed in 19.3% ( 23 / 119 ) of patients with a rheumatic cause compared with 9.3% ( 41 / 439 ) of the nonrheumatic patients ( p < 0.01). Long-term follow-up revealed the necessity for reoperation in 7.8% ( 5 / 64 ) in patients with calcium debridement as compared with 7.7% ( 38 / 494 ) with no debridement ( p = not significant). Cumulative freedom from reoperation at 10 years was 83.3% for all patients, 88.1% for debrided patients, and 82.6% for nondebrided patients ( p = not significant). Cox proportional hazards analysis revealed that the presence of rheumatic disease significantly increased the risk of reoperation (odds ratio = 3.28; p < 0.001), whereas calcium debridement had no significant effect. These results demonstrate that when good annulus and leaflet motion can be achieved in calcified mitral valves, calcium debridement allows durable repairs.

Mitral Balloon Valvuloplasty by Inoue Technique without Echocardiographic Standby

Mitral balloon valvuloplasty (MBV) by Inoue technique was performed in 85 patients with symptomatic rheumatic mitral stenosis (MS). Twenty-eight patients were male and 57 patients were female. The age range was nine to 59 years (mean 28). All patients were subjected to echocardiographic and Doppler examinations before and one day after the procedure. The first 57 patients were subjected to exercise tolerance tests (ETT) a few days before and a few days after the procedure. An echocardiographic score was measured regarding valve thickening, leaflet mobility, degree of calcification and the severity of involvement of subvalvular apparatus. The mitral valve area (MVA) increased from 0.9 +/- 0.2 cm2 to 1.9 +/- 0.45 cm2, (P<0.0001). The mitral gradient (MG) decreased from 20 +/- 5.8 mm/Hg to 5.05 +/-+ 3.2 mm/Hg (P<0.0001). Mean left atrial pressure (LAP) dropped from 25.85 +/- 8.4 mm/Hg to 11.05 +/- 5.4 mm/Hg (P<0.0001). Exercise tolerance test (ETT) increased from 5.59 +/- 1.3 to 11.75 +/- 1.48 min. (P<0.0001). Complications included severe mitral regurgitation (MR) in two patients (2.3%). In the first 57 patients, mild left-to-right shunt measured by green dye dilution technique had occurred in 40% of patients. In conclusion, MBV by Inoue balloon is a good alternative to surgical commissurotomy and echocardiographic standby is very helpful when it is available. However, MBV can be safely performed if echocardiography is inaccessible.

Obstruction of the St. Jude Medical Valve - Diagnostic and Therapeutic Values of Cineradiography

Between 1984, and 1992, we observed 8 patients with an obstructed St. Jude Medical (SJM) valve. Of these, 1 had an obstructed SJM valve in the aortic position, 3 in the mitral position, and 4 in the tricuspid position. Diagnosis of obstruction of the SJM valve was made by cineradiography combined with echocardiography in all 8 patients. Restriction or absence of movement of the leaflet of the SJM valve was observed by cineradiography in all of the 8 patients. Normal range of leaflet mobility of the SJM valve was measured by conventional cineradiography in 70 patients with a normal SJM valve, and the results were compared with the leaflet mobility obtained from the 8 patients with an obstructed SJM valve. In this study, leaflet function in the obstructed SJM valve was strikingly abnormal, with both opening and closing angles, and leaflet motion clearly outside the normal range. Of the 8 patients, 4 underwent urgent prosthetic valve replacements after cineradiography and echocardiography were carried out. Thrombolysis using urokinase was performed in 4 patients, and this treatment was successful in 1 patient. Efficacy of thrombolytic therapy was evaluated by repeat cineradiography. Three of the 4 patients who received thrombolysis showed no significant improvement of leaflet mobility after at least 72 hours of thrombolytic therapy, and finally required surgical correction for the obstructed SJM valve. We believe that cineradiography combined with echocardiography is the optimal method for the diagnosis of obstruction of the SJM valve, and to follow the effect of thrombolytic therapy on prosthetic valve function.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous balloon mitral valvuloplasty: Analysis of echocardiographic and other variables related to outcome

To determine whether mitral valve (MV) morphology influences the result of balloon mitral valvuloplasty (BMV) for mitral stenosis, two-dimensional echocardiography was performed before BMV in 53 patients and in 25 normal controls. The two-dimensional echocardiographic features of MV leaflets: thickness, length and motion, diastolic MV excursion, chordal length, MV annular diameter (MVAnD), subvalvular distance ratio (SDR), and effective balloon dilating area (EBDA) and diameter (EBDD) were then correlated to the immediate post-BMV mitral valve area (MVA). For the total patient population, post-BMV MVA increased from 0.76 ± 0.24 to 1.91 ± 0.59 cm 2 ( p < 0.0001) and mean diastolic transmitral gradient decreased from 20.1 ± 6.15 to 5.8 ± 3.29 mm ( p < 0.0001). The patients were divided into two groups on the basis of post-BMV MVA. Group I had post-BMV MVA <2.0 cm 2 and group II had post-BMV MVA ≥2.0 cm 2. A statistically significant difference was noted in SDR (0.33 ± 0.057 vs 0.45 ± 0.042, p < 0.0001); mid-MV anulus to tip of papillary muscle (PM) distance (20.0 ± 3.8 vs 27.9 ± 4.54 mm, p < 0.0001); chordal length (4.3 ± 3.6 vs 9.8 ± 3.9 mm, p < 0.0001); diastolic MV excursion (15.5 ± 2.6 vs 18.2 ± 4.2 mm, p < 0.01); leaflet mobility ( p < 0.05); and EBDA (4.4 ± 0.6 vs 4.9 ± 0.5 cm 2, p < 0.01). On discriminant function analysis of all the echocardiographic variables, the SDR had the strongest discriminating power, followed by mid-MV anulus to tip of PM distance, EBDD MVAnD , and EBDA/body surface area (BSA), and had an accuracy of 90.6% for correctly differentiating two groups. We conclude that quantitative assessment of SDR, mid-MV anulus to tip of PM distance, EBDD MVAnD by two-dimensional echocardiography, and EBDA BSA are helpful in predicting the immediate outcome of BMV.

Morphological determinants of echocardiographic patterns of mitral valve systolic anterior motion in obstructive hypertrophic cardiomyopathy.

The morphological determinants of mitral valve systolic anterior motion (SAM) and obstruction to left ventricular outflow in patients within the broad clinical spectrum of hypertrophic cardiomyopathy (HCM) are not completely understood, particularly the contribution of mitral leaflet length and size. To clarify this issue, mitral valve specimens from 43 patients with HCM and basal outflow obstruction were used to relate morphometric measurements of leaflet area to certain morphological and functional assessments of left ventricular outflow tract geometry and valvular motion obtained from echocardiograms in the same patients. Twenty-four patients (56%) had mitral valves of normal size (leaflet area < 12.0 cm2) and 19 patients (44%) had enlarged and elongated valves (area > or = 12.0 cm2). Compared with normal-sized mitral valves, the enlarged valves were situated more posteriorly in a larger left ventricular outflow tract (cross-sectional area, 3.3 +/- 1.0 versus 1.9 +/- 0.7 cm2 for normal-sized valves; p < 0.001) and also had greater systolic excursion of the anterior leaflet (16.2 +/- 4.5 versus 13.3 +/- 3.3 mm, p < 0.02), usually with a distinctive sharp-angled bend and localized contact of the leaflet tip with ventricular septum ("typical" SAM); this pattern of SAM was possible because the central and distal portions of the leaflet were relatively free of fibrous thickening. In contrast, normal-sized mitral valves were situated more anteriorally in a smaller left ventricular outflow tract and frequently showed a different mechanism of SAM and subaortic obstruction with relatively limited leaflet motion, absence of a sharp bend, and septal contact involving more substantial portions of the anterior leaflet and contiguous chordae ("atypical" SAM); mitral-septal apposition was effected in large measure by posterior ventricular septal motion. This pattern of SAM was invariably associated with a more diffuse pattern of fibrous thickening. Patients with obstructive HCM show patterns of mitral valve SAM that are diverse and determined largely by the interrelation of left ventricular outflow tract geometry, the size and mobility of the mitral leaflets, and the presence and distribution of fibrous thickening.

Influence of mitral valve morphology on mitral balloon commissurotomy: Immediate and six-month results from the NHLBI Balloon Valvuloplasty Registry

Echocardiographic data were analyzed in 555 patients undergoing mitral balloon commissurotomy (MBC). Patients were enrolled in the National Heart, Lung, and Blood Institute Balloon Valvuloplasty Registry from 24 centers. There were 456 women and 99 men with a mean age of 54 years. Before MBC the two-dimensional echocardiographic variables of mitral valve thickness, mobility, calcification, and subvalvular disease were evaluated and assigned scores of 1 to 4. The mitral valve morphology score was related to mitral valve area (MVA) measured after MBC by cardiac catheterization. The leaflet mobility score was related to the immediate post-MBC MVA: 2.2 ± 0.8 cm 2 for grade 1, 1.9 ± 0.7 cm 2 for grade 2, 1.7 ± 0.7 cm 2 for grade 3, and 1.9 ± 0.9 cm 2 for grade 4 ( p < 0.001). Results of the MVA after MBC showed a similiar relationship for each echocardiographic variable. The total morphology score (sum of the four variables) showed a weak relationship to MVA immediately after MBC ( r = −0.24), which was persistent at 6 months after MBC ( r = −0.25). Multiple regression analysis showed that the MVA after MBC is predicted by pre-MBC MVA ( p < 0.001), left atrial size ( p = 0.01), balloon diameter ( p = 0.02), cardiac output ( p = 0.004), and leaflet mobility ( p = 0.01). The R 2 of the model was 0.31 ( p < 0.001). Total morphology score, leaflet thickness, calcification, and subvalvular disease were not important univariate or multivariate predictors of the results of MBC. These data suggest that although mitral valve morphology, particularly leaflet mobility, relates to MVA after MBC, other variables such as the severity and duration of disease are also important and are influenced by the larger balloon sizes used in the procedure. Mitral valve morphology should not be used alone in the selection of patients for MBC.

Long-term (9 to 33 months) echocardiographic follow-up after successful percutaneous mitral commissurotomy

Late results after successful percutaneous mitral commissurotomy were assessed by prospective clinical and echocardiographic follow-up. Fiftyseven patients were followed for a mean of 19 ± 6 months (range 9 to 33) after the procedure. Mitral valve area (measured by Doppler half-time method) increased from 1.0 ± 0.2 to 2.2 ± 0.5 cm 2 immediately after commissurotomy, and then decreased to 1.9 ± 0.5 cm 2 at follow-up (p < 0.05), whereas gradient did not change after its immediate postcommissurotomy reduction. Echocardiographic restenosis (mitral valve area ≤1.5 cm 2 with >50% reduction of initial gain) was seen in 12 of 57 patients (21%). Atrial shunting, detected by transthoracic color Doppler in 61% of patients immediately after the procedure (color flow jet through atrial septum), persisted in 30% at follow-up. Restenosis by univariate analysis correlated with age, smaller valve area after the procedure, and higher echocardiographic score. Multivariate analysis identified leaflet mobility and calcifications as the components of a score that was predictive for restenosis. Magnitude of shunt (pulmonary-to-systemic flow ratio >1.5), use of a Bifoil balloon (2 balloons on 1 shaft), and smaller valve area after the procedure were predictors by multivariate analysis of the persistence of atrial shunting. Clinical improvement persisted at long-term follow-up (mean New York Heart Association class 1.6 ± 0.6 vs 2.6 ± 0.6 before commissurotomy). Improvement of ≥1 functional class was seen in 75% of patients (80% of those without and 58% of those with restenosis); patients with a shunt did not differ from the entire group. Thus, percutaneous mitral commissurotomy provides excellent late (9 to 33 months) clinical results. Echocardiographic restenosis was identified in 20% of patients, and was related to age, valve morphology and a suboptimal result. Atrial shunting (small and clinically well-tolerated) was absent after long-term follow-up in 50% of patients; its persistence was related to the magnitude of the shunt, the size of the deflated balloon, and a suboptimal result.

Pathomorphological aspects, aetiology and natural history of acquired mitral valve stenosis

Commissural fusion, leaflet thickening and alteration of the subvalvular apparatus are dominant mechanisms causing clinically important mitral stenosis (MS) of rheumatic origin. Calcification and a consequent decrease in leaflet mobility are subsequent features in rheumatic MS and may be the primary mechanisms in MS of degenerative origin. In 1051 consecutive patients with pure or predominant MS requiring surgical intervention, aetiology was rheumatic in 76.9%, infective in 3.3%, degenerative (severe annular and leaflet calcification) in 2.7% and congenital (Lutembacher syndrome) in 1.2%; it was the result of systemic lupus erythematosus (n = 4), carcinoid heart disease (n = 2), endomyocardial fibrosis (n = 2) and rheumatoid arthritis (n = 2) in less than 1%, while in 14.5% of these patients aetiology remained unclassified. The natural history of rheumatic MS is characterized by an asymptomatic latent period, following the initial rheumatic fever (RF). In a prospective study of MS (n = 159) the mean interval between RF and the appearance of symptoms was 16.3 +/- 5.2 years. Twenty-five years after the initial RF 8% of the patients were still asymptomatic, 9% were class II (NYHA), 33% class III and 50% had been operated or were class IV. Progress from mild to severe disability took 9.2 +/- 4.3 years on average. When valve surgery was indicated but refused by the patients, survival with medical treatment was 0.44 +/- 0.06 after 5 years, 0.32 +/- 0.08 after 10 years and 0.19 +/- 0.09 after 15 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous Mitral Valvuloplasty Using the Double Balloon Technique: Immediate Results and Determinant Factors of Increasing Mitral Regurgitation

Percutaneous mitral valvuloplasty (PMV) was successfully performed in 112 (95%) out of 118 patients (32 M, 80 F, mean age: 38±11 years) with mitral stenosis. There was a significiant increase in the mitral valve area (MVA) from 0.9±0.2 to 2.0±0.7 cm2 p<0.0001, a decrease in the mean mitral gradient from 17±6 to 6±3 mmHg, p<0.001, and a rise in cardiac output from 4.3±0.8 to 4.8±1.2 L/min, p<0.001.The morphologic features of the mitral stenosis was evaluated using echocardiographic score. Patients with a low-score (≤8) had more effective dilation of mitral stenosis compared to patients with a high-score over 8 (0.9 to 2.2 vs 0.8 to 1.6 cm2, p<0.001), despite the similar EBDA/BSA (effective balloon dilating area/body surface area). The patients with good results after PMV (MVA ≥ 1.5 cm2) were more likely to be in normal sinus rhythm (p<0.0001), younger age (p<0.001), smaller left atrial size (p<0.05), and lower total echoscore (p<0.002), especially in leaflet mobility (p<0.02) and degree of calcification (p<0.002), compared to patients with relatively poor result after PMV (MVA < 1.5 cm2). There were no differences in EBDA/BSA, calcification on fluoroscopy, and history of previous surgical commissurotomy between the 2 groups. Mitral regurgitation (MR) developed or increased in severity in 41 (37%) cases. The patients with an increase in MR had relatively smaller initial MVA (p<0.001) and more thickened valve leaflets (p<0.02). Although there was an increasing trend in total echoscore and EBDA as the severity of the MR increased, those were statistically not significant. Complications included embolic episode in 3 (3%), cardiac tamponade in 3 (3%), and creation of ASD (Qp/Qs≥1.5) in 22 (20%).Thus this data suggest that valvuloplasty using the double-balloon technique is a safe and effective procedure in selected patients; mitral valve dilation was more effective in younger patients with normal sinus rhythm, smaller left atrium, more mobile and less calcified valve leaflets and lower total echoscore; and an increase in MR after valvuloplasty appeared to be related to initial mitral valve area and valvular thickening.

Aortic valve decalcification

Ultrasonic decalcification of the aortic valve was performed in 22 elderly patients with critical aortic stenosis (aortic valve areas less than 0.8 cm2) as an alternative to prosthetic valve replacement. All of the patients had symptoms. The mean New York Heart Association class was 3.3 +/- 0.9. Adequate decalcification with restoration of leaflet mobility was achieved in all patients, including seven with bicuspid aortic valves. Leaflet perforation occurred and was successfully repaired in five patients. Ten patients underwent concomitant myocardial revascularization. There were two operative deaths (9%) and three late deaths. Echocardiograms were obtained preoperatively, postoperatively, and at 6 months. The mean aortic valve area increased significantly from 0.72 +/- 0.17 to 1.42 +/- 0.31 cm2 (p less than 0.001) and the peak gradient decreased from 74 +/- 34 to 25 +/- 13 mm Hg (p less than 0.001). At 6 months the aortic valve area (1.29 +/- 0.48 cm2) and peak gradient (31 +/- 12 mm Hg) continued to be significantly better than the preoperative measurements (p less than 0.001), but the 6-month aortic valve area was slightly decreased and the gradient increased when compared with the immediate postoperative values (p less than 0.02). The prevalence of mild to moderate aortic insufficiency increased from 50% of the patients preoperatively to 87% at 6 months (p less than 0.05). Two patients subsequently required aortic valve replacement for restenosis and aortic insufficiency. Ultrasonic decalcification is effective in relieving aortic stenosis, but subsequent restenosis and insufficiency may limit its application.

Valve repair with Carpentier techniques: The second decade

Among 206 consecutive patients having undergone mitral valve repair with a prosthetic ring between 1972 and 1979 in our institution, the 195 patients (94.5%) who survived the operation were studied to assess the long-term function of this method of repair. Patients' ages ranged from 18 to 79 years (mean age 48.7 years). Mitral valve insufficiency was due to degenerative disease in 113 patients (58%), rheumatic disease in 74 (38%), ischemia and other causes in eight patients (4%). A total of 188 patients (9.7%) were in New York Heart Association class III or IV preoperatively and 94 (48%) had atrial fibrillation. The patients were divided into three functional groups: type I (normal leaflet motion), 35 patients (18%); type II (leaflet prolapse), 147 patients (75%); and type III (restricted leaflet motion), 13 patients (7%). The techniques included prosthetic ring annuloplasty (185 patients), leaflet resection (158 patients), chordal shortening (89 patients), leaflet mobilization (10 patients) and papillary muscle reimplantation (2 patients). Long-term follow-up was available in 189 patients (96.8%), for a rate of 2316 patients per year. The 15-year actuarial and valve-related survival rates were 72.4% and 82.8%, respectively. At 15 years, 93.9% of the patients were free from thromboembolism, 96.6% free from endocarditis, 95.6% free from anticoagulant-related hemorrhage, and 87.38% free from reoperation. Actuarial rate of freedom from reoperation was higher in the group with degenerative disease (92.7%) than in the group with rheumatic disease (76.12%). Among the 157 survivors, 117 (74%) were in New York Heart Association class I and class II and 105 (66%) were in sinus rhythm. Doppler echocardiographic studies showed normal ventricular contractility in 134 patients (84.5%), absence of mitral regurgitation in 112 (74%), trivial regurgitation in 27 (17%), and significant regurgitation in 4 patients (2.5%).

Aortic valve debridement by ultrasonic surgical aspirator: A word of caution

Aortic stenosis was relieved in 11 patients by ultrasonic debridement of the valve and annulus, while 102 other patients underwent valve replacement for aortic stenosis during 1988. Debridement was selectively applied based on findings of small annulus size (19 mm or less) and extensive calcification. Additional patient characteristics were mean transvalvular gradient of 78 mm Hg, advanced age, and marked left ventricular hypertrophy. Six patients had no residual gradient and 5 others a mean gradient less than 10 mm Hg. There were no complications related to the debridement process. Intraoperative transesophageal Doppler echocardiography demonstrated improved leaflet mobility and elimination of the gradient in all patients and elimination of associated valvular insufficiency in 2 patients. Follow-up echocardiography demonstrated late onset of new valvular regurgitation in 5 patients that was progressive and required reoperation in 3. Thickened, hardened, and retracted valve leaflets with loss of central coaptation were found in all 3 patients who underwent reoperation. Ultrasonic debridement can effectively relieve aortic stenosis, provide an excellent immediate hemodynamic result, and decrease operative time. However the early occurrence of aortic insufficiency in a high percentage of patients makes it an unacceptable alternative to valve replacement, and the technique should be abandoned as a treatment for severe calcific aortic stenosis.

Effect of balloon aortic valvuloplasty on the dynamics of left ventricular ejection.

To evaluate the effect of balloon aortic valvuloplasty on left ventricular ejection dynamics, simultaneous left ventricular and aortic pressures were obtained by use of a micromanometer catheter in nine patients before and after the procedure. Ejection times, stroke volumes (thermodilution), ejection rates, and pressure gradients were measured. For each parameter, ejection was then divided into two components: accelerative (onset systole to peak gradient) and decelerative (peak gradient to end systole). After valvuloplasty, there was 1) a decrease in overall ejection time and in mean and peak pressure gradients; 2) an increase in overall ejection rate; 3) no change in stroke volume or heart rate; 4) an increase in both accelerative and decelerative ejection rates and a decrease in the decelerative ejection time (expressed as a percentage of the R-R interval); and 5) a decrease in the time for the ejection of the final 25% of stroke volume (P less than 0.01) and time occupied by the final 25% of the gradient. Immediately following balloon aortic valvuloplasty, there is a decrease in ejection time and in increase in ejection rate. Balloon aortic valvuloplasty has a significant effect on the dynamics of left ventricle ejection, with changes primarily expressed in late systole. By improving the mobility of calcified leaflets, balloon aortic valvuloplasty may reduce the forces opposing forward blood movement during the decelerative phase of ejection.

In utero diagnosis of interrupted aortic arch with transposition of the great arteries and tricuspid atresia

valve contained much more extensive nodule formation and fibrotic leaflets more typical of “senile” calcific aortic stenosis. Whether this is coincidental cannot be determined with only two specimens. One could postulate, however, that a very heavily calcified and fibrotic valve may not have sufficient flexibility or space within the sinus of Valsalva to be effectively dilated. In valve No. 3, which was dilated twice, we noted that the right coronary leaflet contained a massive nodule that had no evidence of fracture after either the first or second attempts (Fig. 1). The other two leaflets, with smaller nodules, had clearly visible gross fissures in the nodules, clearly due to the second attempted PV. This may be related to the large mass of the calcific nodule, which simply could not be deformed sufficiently to crack it within the restricted space of the sinus of Valsalva. In conclusion, we have identified evidence of hemorrhage and thrombosis into valve leaflets after PV, and of healing of fissures created by dilatation. We have postulated that the extent of nodule formation and nodule size may influence the ability of the inflated balloon to create fractures, and thus increase leaflet mobility. These factors may play a role in both immediate and long-term outcome in valvuloplasty for calcific aortic stenosis.

Doppler echocardiographic assessment of the effect of balloon aortic valvuloplasty on left ventricular systolic function

In order to evaluate the effects of balloon aortic valvuloplasty on left ventricular systolic function and ejection dynamics, Doppler echocardiographic studies were performed on 29 patients before and following valvuloplasty. Continuous wave aortic velocity signais were digitized and (with catheterization laboratory before and after valvuloplasty valve areas) were used to calculate: stroke volume; ejection time; ejection rate; time to 25%, 50%, and 75% ejection; accelerative (onset systole to peak velocity) ejection volume, time, and rate; and decelerative (peak velocity to end systole) ejection volume, time, and rate. Following valvuloplasty, there were no significant changes in heart rate; time to 25%, 50%, and 75% ejection; accelerative ejection time; and decelerative ejection time. There were significant increases in stroke volume, total ejection rate, accelerative ejection volume, decelerative ejection volume, accelerative ejection rate, and decelerative ejection rate, and a significant decrease in total ejection time. Balloon aortic valvuloplasty has a significant effect on the dynamics of left ventricular ejection. There is an increase in stroke volume and a decrease in ejection time, with relatively little effect on early systole, and a more pronounced effect in late systole. There are significant increases in accelerative and decelerative ejection volumes and rates, and a decrease in the time required for the last 25% of ejection. By improving the mobility of calcified leaflets, balloon aortic valvuloplasty may reduce the forces opposing forward blood movement during the decelerative phase of aortic ejection.

Percutaneous balloon dilatation of the mitral valve: an analysis of echocardiographic variables related to outcome and the mechanism of dilatation.

Twenty two patients (four men, 18 women, mean age 56 years, range 21 to 88 years) with a history of rheumatic mitral stenosis were studied by cross sectional echocardiography before and after balloon dilatation of the mitral valve. The appearance of the mitral valve on the pre-dilatation echocardiogram was scored for leaflet mobility, leaflet thickening, subvalvar thickening, and calcification. Mitral valve area, left atrial volume, transmitral pressure difference, pulmonary artery pressure, cardiac output, cardiac rhythm, New York Heart Association functional class, age, and sex were also studied. Because there was some increase in valve area in almost all patients the results were classified as optimal or suboptimal (final valve area less than 1.0 cm2, final left atrial pressure greater than 10 mm Hg, or final valve area less than 25% greater than the initial area). The best multiple logistic regression fit was found with the total echocardiographic score alone. A high score (advanced leaflet deformity) was associated with a suboptimal outcome while a low score (a mobile valve with limited thickening) was associated with an optimal outcome. No other haemodynamic or clinical variables emerged as predictors of outcome in this analysis. Examination of pre-dilatation and post-dilatation echocardiograms showed that balloon dilatation reliably resulted in cleavage of the commissural plane and thus an increase in valve area.

The Pathogenesis of Leaflet Failure in Prosthetic Venous Valves

Recent work from this laboratory established feasibility for long-term patency of properly designed valvular xenografts placed without technical fault in the inferior vena cava. Limitations of that work however, included perileaflet fibrosis with reduction of leaflet mobility. The current study evaluates perileaflet thrombosis potentiated by the nonendothelialized leaflet surface as the primary pathogenic mechanism of this problem. The study includes 18 pericardial xenograft valvular bioprostheses and nine jugular vein valvular autografts placed in the inferior vena cava of 27 dogs All animals received a single bolus of heparin (100u/kg) 5min before vascular clamping. The valves were removed and examined from 1 day to 7.5 months after placement. In valvular xenografts, perileaflet thrombosis by 1 day progressed to dense fibrosis at 2 months. Despite limitation of leaflet motion, this process caused luminal occlusion in only three valves (83% patency). There were no failures in the nine valvular autografts, with normal valve leaflets and no evidence of thrombus formation as late as 6 months. Perileaflet thrombosis in pericardial xenograft bioprostheses is a primary event in the ultimate fibrosis of these prosthetic venous valves. Inhibition of thrombosis by the venous endothelial lining may be an explanation for success with the smaller valvular autografts in the same haemodynamic environment.

Echocardiographic Evaluation of Mitral Valve Structure and Function in Patients Followed for at Least 6 Months After Percutaneous Balloon Mitral Valvuloplasty

Although beneficial results have been reported immediately after percutaneous mitral balloon valvuloplasty, little information is available concerning the longer-term outcome of this procedure. The anatomic and functional results of percutaneous mitral valvuloplasty were assessed in 20 patients, in whom two-dimensional and Doppler echocardiographic examination could be obtained both immediately and 6 to 11 months (mean 7.5 +/- 2.0) after balloon dilation. Mean valve area measured by planimetry decreased slightly but significantly from 1.90 +/- 0.59 cm2 immediately after valvuloplasty to 1.62 +/- 0.55 cm2 (p less than 0.001) at follow-up. Individual changes in valve area were variable, and in four patients valve area decreased by greater than 25%. Echocardiographic scores of valvular morphology were obtained by assigning scores of 0 to 4 (with increasing abnormality) to each of four morphologic characteristics of the valve, namely, leaflet mobility, thickening, calcification and subvalvular thickening. This score was higher in the four patients with a decrease in valve area greater than 25% at follow-up than in the other patients (11 +/- 2 versus 7 +/- 2, p less than 0.002). Multiple regression analysis of several hemodynamic and echocardiographic factors identify first the echocardiographic score and second the valve area postvalvuloplasty as the only significant predictors of the percent decrease in valve area (r = 0.70, p less than 0.006). Mitral regurgitation graded by pulsed Doppler ultrasound decreased from 1.9 +/- 1.2 immediately after valvuloplasty to 1.0 +/- 0.9 (p less than 0.003) at follow-up, whereas there was no change in mean transmitral pressure gradient by Doppler echocardiography (5 +/- 2 versus 6 +/- 3 mm Hg, p = NS) and left atrial volume (74 +/- 34 versus 72 +/- 27 cm3, p = NS). Thus, 6 to 11 months after balloon mitral valvuloplasty, mean mitral valve area decreases slightly. Individual changes in valve area, however, are variable. Valvular morphology assessed by two-dimensional echocardiography may be useful for identifying those patients who have an increased likelihood of developing valvular restenosis.

Postmortem and intraoperative balloon valvuloplasty of calcific aortic stenosis in elderly patients: Mechanisms of successful dilation

Percutaneous balloon dilation of the aortic valve has recently been proposed as a palliative procedure for treating nonsurgical candidates with calcific aortic stenosis. To assess the safety, efficacy and mechanisms of successful balloon valvuloplasty, postmortem (n = 33) and intraoperative (n = 6) balloon aortic valvuloplasty was performed in the hearts of 39 elderly patients with calcific aortic stenosis. The cause of aortic stenosis was degenerative nodular calcification in 28 cases, calcific bicuspid aortic stenosis in 8 cases and rheumatic heart disease in 3 cases. Balloon dilation was performed with 15 to 25 mm balloons in the postmortem specimens, and with 18 to 20 mm balloons in the operating room immediately before aortic valve replacement. After balloon dilation, valve orifice dimensions and leaflet mobility increased in all patients. The mechanisms of successful dilation included fracture of calcified nodules in 16 aortic valves, separation of fused commissures in 5 valves, both in 6 valves and grossly inapparent microfractures in 12 valves. Valve leaflet avulsion occurred in one heart after inflation with a clearly oversized balloon. Liberation of calcific debris, valve ring disruption or midleaflet tears did not occur in any heart. In conclusion, there are at least three mechanisms of successful aortic valvuloplasty, depending on the origin of valvular stenosis. Embolic phenomena and acute valvular regurgitation do not appear to be likely events associated with this procedure.