Evaluation of left atrial contribution to left ventricular filling in aortic stenosis by velocity-encoded cine MRI

Velocity-encoded cine MRI (VEC-MRI) can measure volume flow at specified site in the heart. This study used VEC-MRI to measure flow across the mitral valve to compare the contribution of atrial systole to left atrial filling in normal subjects and patients with left ventricular hypertrophy. The study population consisted of 12 normal subjects (mean age 34.5 years) and nine patients with various degrees of left ventricular hypertrophy resulting from aortic stenosis (mean age 70 years). VEC-MRI was performed in double-oblique planes through the heart to measure both the mitral inflow velocity pattern (E/A ratio) and the volumetric flow across the mitral valve. The left atrial contribution to left ventricular filling (AC%) was calculated. The results were compared with Doppler echocardiographic parameters. The VEC-MRI-derived mitral E/A ratios showed a significant linear correlation with E/A ratios calculated from Doppler echocardiography (r = 0.94), and the VEC-MRI-derived E/A ratios (2.1 +/- 0.5 vs 1.0 +/- 0.4) and AC% values (24.9 +/- 7.2 vs 45.7 +/- 16.4) were significantly different between normal subjects and patients with aortic stenosis (p < 0.01 in both groups). The same differences were seen in the Doppler echocardiographic parameters. The VEC-MRI-derived E/A ratio and AC% showed significant hyperbolic and linear correlations with left ventricular mass indexes (r = 0.95 and 0.86). In addition, the VEC-MRI-determined E/A ratio and the volumetric AC% displayed a highly significant hyperbolic correlation (r = 0.95). Thus VEC-MRI can be used to evaluate left ventricular diastolic filling characteristics in normal subjects and patients with abnormalities of diastolic filling.     

Adjustable tricuspid valve annuloplasty assisted by intraoperative transesophageal color Doppler echocardiography

Intraoperative transesophageal echocardiography (TEE) can play a major role in active guidance of cardiac surgery. This study describes a new application of TEE for assisting tricuspid suture annuloplasty. Twenty-five patients (aged 52 +/- 11 years) who underwent mitral valve replacement and tricuspid valve annuloplasty were studied intraoperatively by TEE. After cardiopulmonary bypass, the suture annuloplasty was adjusted on the beating heart until palpable regurgitation was eliminated. Further adjustment of the suture was performed under echocardiographic guidance until color Doppler flow imaging showed the most adequate correction of tricuspid regurgitation (TR). A significant decrease in the semiquantitative grade of TR, of regurgitant jet area and of the ratio jet area/right atrial area was obtained when the suture was adjusted under echocardiographic guidance. The peak inflow velocity and the gradient across the tricuspid valve did not show significant changes throughout the procedures. The results showed that the tricuspid suture annuloplasty guided by TEE enables a substantial reduction in residual TR without creating valve stenosis.     

Risk of stroke in a cohort of 815 patients with calcification of the aortic valve with or without stenosis

BACKGROUND AND PURPOSE: We sought to establish the possible role of calcification of the aortic valve with or without stenosis as a risk factor for stroke. METHODS: Occurrences of stroke, stroke subtypes, and concomitant cardiovascular risk factors were prospectively analyzed in 300 patients with echocardiographic evidence of aortic valve calcification, 515 patients with calcified aortic valve stenosis, and 562 control subjects. RESULTS: Twenty-four patients with aortic valve calcification, 24 patients with calcified aortic valve stenosis, and 27 control subjects had a stroke during follow-up. Using Cox proportional hazards models, we found that strokes were not significantly associated with aortic valve calcification with or without stenosis, but hypertension and any carotid stenosis were associated. On multiple logistic regression analysis, we did not find any association between one of the two valve lesions and indirect possible indications of cardiogenic embolism such as territorial as opposed to small deep brain infarcts or the presence of silent brain infarcts. CONCLUSIONS: Aortic valve calcification with or without stenosis is not a risk factor for stroke.     

Doppler haemodynamic assessment of clinically and echocardiographically normal mitral and aortic Allcarbon valve prostheses. Valve Prostheses Ligurian Cooperative Doppler Study

Doppler echocardiographic characteristics of normally functioning Allcarbon prostheses were studied in 149 consecutive patients with 157 valves in the mitral (n = 73) and aortic (n = 84) positions whose function was considered normal by clinical and echocardiographic evaluation. In the mitral position, the mean gradient and the effective mitral orifice area were not significantly different in either the 25-mm or the 31-mm size valves (from 5 +/- 1 to 4 +/- 1 mmHg and from 2.2 +/- 0.6 to 2.8 +/- 0.9 cm2, respectively; P = ns for both). Conversely, peak gradient was significantly and inversely correlated to actual orifice area (r = -0.70; P < 0.0006), decreasing from 15 +/- 3 mmHg in the 25-mm size valve to 9 +/- 1 mmHg in the 31-mm size. In the aortic position, the mean gradient was 29 +/- 8 mmHg in the 19-mm size valve; it decreased to 8 +/- 2 mmHg in the 29-mm size. Effective prosthetic aortic valve area, calculated using the continuity equation, ranged between 0.9 +/- 0.1 cm2 for the 19-mm size valve to 4.1 +/- 0.7 cm2 for the 29-mm size. By analysis of variance, effective prosthetic aortic valve area differentiated various valve sizes (F = 25.3; P < 0.0001) better than peak (F = 5.34; P = 0.012) or mean (F = 4.34; P = 0.0052) gradients alone, and it correlated better with actual orifice area (r = 0.89, r = -0.70 and r = -0.65, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Subendocardial blood flow in children with congenital aortic stenosis

Subendocardial blood flow may be estimated from the ratio of flow to the subendocardium to myocardial oxygen consumption. The first may be estimated from the diastolic pressure time index (area between aortic and left ventricular (LV) pressure during diastole) and the latter by the tension time index (integral of LV pressure during systolic ejection). Subendocardial flow index (SEFI) averaged 1.27 (0.96-1.78) in 13 children with normal aortic valves. SEFI averaged 0.88 (0.43-1.65) in asymptomatic children with congenital aortic stenosis and was never greater than 0.9 in symptomatic children. Aortic valve area and systolic pressure difference did not correlate well with symptoms. SEFI and aortic valve area increased in 26 of 28 patients after surgery. However, 23 of 28 had varying degrees of aortic regurgitation following valvotomy. Since calculation of SEFI is not affected by aortic regurgitation, it would appear to be a more useful measure of surgical success than aortic valve area.     

Aortic valve replacement with cryopreserved aortic allograft: ten-year experience

OBJECTIVE: Cryopreserved aortic allograft can be used for aortic valve replacement in congenital, rheumatic, degenerative, and infected native valve conditions, as well as failed prosthetic valves. This study was conducted to determine the long-term results of aortic valve replacement with cryopreserved aortic allografts. METHODS: Aortic valve replacement with cryopreserved aortic allografts was performed in 117 patients from July 1985 until August 1996. All patients requiring aortic valve replacement regardless of valve disease were considered for allograft replacement; the valve was preferentially used in patients under age 55 years and in the setting of bacterial endocarditis. Four operative techniques involving cryopreserved aortic allografts were used: freehand aortic valve replacement with 120-degree rotation, freehand aortic valve replacement with intact noncoronary sinus, aortic root enlargement with intact noncoronary sinus, and total aortic root replacement. Valve function was assessed by echocardiography during the operation in 78 patients (66%) and after the operation in 77 patients (65%). RESULTS: One-hundred eighteen aortic valve replacements with cryopreserved aortic allografts were performed on 117 patients; mean age was 45.6 years (range 15 to 83 years) and mean follow-up was 4.6 years (range up to 11 years). Intraoperative echocardiography disclosed no significant aortic valve incompetence. There were four operative deaths (3%) and seven late deaths; freedom from valve-related mortality at 10 years was 9:3% +/- 4.55%. New York Heart Association functional status at latest follow-up was normal in 98 (94%) patients. On postoperative echocardiography, 90% had no or trivial aortic valve incompetence. Freedom from thromboembolism at 10 years was 100% and from endocarditis, 98% +/- 2.47%. Seven (6%) patients required valve explantation, four for structural deterioration. At 10 years, freedom from reoperation for allograft-related causes was 92% +/- 3.47%. CONCLUSIONS: Aortic valve replacement with cryopreserved aortic allografts can be performed with low perioperative and long-term mortality. Most patients have excellent functional status, and reoperation for valve-related causes is unusual. Aortic valve replacement with cryopreserved aortic allografts demonstrates excellent freedom from thromboembolism, endocarditis, and progressive valve incompetence.     

Rheumatoid nodules: MR/pathological correlation

A 62-year-old female who had a complaint of palpitation was diagnosed as bicuspid aortic stenosis and left single coronary artery by the echocardiographic examination, cardiac catheterization study and coronary artery angiography. Aortic valve replacement was performed and the patient was discharged 22 days after surgery with good post-operative course. Preoperative coronary artery angiography was important in the case of aortic valvular disease.     

Three-year outcome after balloon aortic valvuloplasty. Insights into prognosis of valvular aortic stenosis

BACKGROUND: To identify predictors of long-term outcome after balloon aortic valvuloplasty, we analyzed data on 674 adults (mean age, 78 +/- 9 years; 56% were women) undergoing this procedure at 24 clinical centers who had a mean initial increase in aortic valve area of 0.3 cm2. METHODS AND RESULTS: Baseline data included clinical, echocardiographic, and catheterization variables. Follow-up data included mortality, cause of death, rehospitalization, 6-month echocardiography, and functional status. Kaplan-Meier curves and log-rank tests were used to evaluate survival in subgroups. Multivariate Cox regression models were used to identify independent predictors of survival. Overall survival was 55% at 1 year, 35% at 2 years, and 23% at 3 years, with the majority of deaths (70%) classified as cardiac by an independent review committee. Rehospitalization was common (64%), although 61% of survivors at 2 years reported improved symptoms. Echocardiography at 6 months (n = 115) showed restenosis from the postprocedural valve area of 0.78 +/- 0.31 cm2 to 0.65 +/- 0.25 cm2 (P < .0001). With stepwise multivariate analysis, sequentially adding clinical, echocardiographic, and catheterization variables, the overall model identified independent predictors of survival as baseline functional status, baseline cardiac output, renal function, cachexia, female gender, left ventricular systolic function, and mitral regurgitation. Baseline and postprocedural variables were examined to identify which subgroup of patients has the best outcome after aortic valvuloplasty. A "lower-risk" subgroup (28% of the study population), defined by normal left ventricular systolic function and mild clinical functional limitation, had a 3-year survival of 36% compared with 17% in the remainder of the study group. CONCLUSIONS: Long-term survival after balloon aortic valvuloplasty is poor with 1- and 3-year survival rates of 55% and 23%, respectively. Although survivors report fewer symptoms, early restenosis and recurrent hospitalization are common.     

Simultaneous determination of aortic valve area by the Gorlin formula and by transesophageal echocardiography under different transvalvular flow conditions. Evidence that anatomic aortic valve area does not change with variations in flow in aortic stenosis

OBJECTIVES: The purpose of this study was to determine the impact of changes in flow on aortic valve area (AVA) as measured by the Gorlin formula and transesophageal echocardiographic (TEE) planimetry. BACKGROUND: The meaning of flow-related changes in AVA calculations using the Gorlin formula in patients with aortic stenosis remains controversial. It has been suggested that flow dependence of the calculated area could be due to a true widening of the orifice as flow increases or to a disproportionate flow dependence of the formula itself. Alternatively, anatomic AVA can be measured by direct planimetry of the valve orifice with TEE. METHODS: Simultaneous measurement of the planimetered and Gorlin valve area was performed intraoperatively under different hemodynamic conditions in 11 patients. Left ventricular and ascending aortic pressures were measured simultaneously after transventricular and aortic punctures. Changes in flow were induced by dobutamine infusion. Using multiplane TEE, AVA was planimetered at the level of the leaflet tips in the short-axis view. RESULTS: Overall, cardiac output, stroke volume and transvalvular volume flow rate ranged from 2.5 to 7.3 liters/min, from 43 to 86 ml and from 102 to 306 ml/min, respectively. During dobutamine infusion, cardiac-output increased by 42% and mean aortic valve gradient by 54%. When minimal flow was compared with maximal flow, the Gorlin area varied from (mean +/- SD) 0.44 +/- 0.12 to 0.60 +/- 0.14 cm2 (p < 0.005). The mean change in Gorlin area under different flow rates was 36 +/- 32%. Despite these changes, there was no significant change in the planimetered area when minimal flow was compared with maximal flow. The mean difference in planimetered area under different flow rates was 0.002 +/- 0.01 cm2 (p = 0.86). CONCLUSIONS: By simultaneous determination of Gorlin formula and TEE planimetry valve areas, we showed that acute changes in transvalvular volume flow substantially altered valve area calculated by the Gorlin formula but did not result in significant alterations of the anatomic valve area in aortic stenosis. These results suggest that the flow-related variation in the Gorlin AVA is due to a disproportionate flow dependence of the formula itself and not a true change in valve area.     

Echocardiographic hemodynamic and morphometric predictors of survival after two-ventricle repair in infants with critical aortic stenosis

OBJECTIVES: The purpose of this study was to identify echocardiographic hemodynamic and morphometric factors that would predict which infants with critical aortic stenosis could undergo relief of left ventricular outflow obstruction as opposed to the Norwood procedure. BACKGROUND: Echocardiographic predictors of survival in infants with critical aortic stenosis after two-ventricle repair have been mainly limited to morphometric factors, which have limitations. Echocardiographic hemodynamic predictors of survival in these patients have not previously been studied. METHODS: Doppler color flow mapping and pulsed Doppler techniques were used to obtain hemodynamic measurements of flow in the ascending, transverse and descending aorta, the ductus arteriosus, and across the aortic and mitral valves in infants with critical aortic stenosis. Morphometric measurements of the left heart structures were obtained, and comparisons were made between survivors and nonsurvivors for the hemodynamic and morphometric factors. RESULTS: Twenty-eight infants (mean age 1 +/- .6 days, mean weight 3.6 +/- .6 kg) with critical aortic stenosis were evaluated. Nineteen had a two-ventricle repair initially attempted, and nine had a Norwood operation. Among the patients with a two-ventricle repair, the hemodynamic factors associated with survival after two-ventricle repair included predominant or total antegrade flow in the ascending (p < 0.01) and transverse aorta (p < 0.05). Aortic valve gradient, mitral valve inflow and direction of flow in the ductus arteriosus and descending aorta were unrelated to outcome. The morphometric factors associated with survival after two-ventricle repair included the indexed aortic annulus (p < 0.0002), aortic root (p < 0.003), ascending aorta (p < 0.008) and left ventricular long-axis length (p < 0.01). Left ventricular volume, mass, ejection fraction and mitral valve area were not related to outcome after two-ventricle repair. CONCLUSIONS: In infants with critical aortic stenosis, predominant or total antegrade flow in the ascending and transverse aorta was associated with survival after two-ventricle repair. Determination of a one- versus two-ventricle repair remains a complex issue in infants with critical aortic stenosis. In addition to established morphometric predictors, hemodynamic information on the direction of flow in the aorta may help to define candidates for the Norwood operation.     

In-vitro isolation and antifungal susceptibility of amphotericin B-resistant mutants of Aspergillus fumigatus

BACKGROUND AND AIMS OF THE STUDY: Aortic valve disease in the pediatric population poses special problems to surgeons and cardiologists. The pulmonary autograft has proven to be a good alternative for aortic valve replacement and left ventricular outflow tract (LVOT) reconstruction in this special group. METHODS: Forty-one children (mean age 10.0 +/- 4.8 (SD) years; range: 35 days to 18.8 years) underwent aortic root replacement with a pulmonary autograft between February 1994 and April 1998. Twenty-one patients (51%) had previous cardiac surgery; seven (17%) had balloon valvulotomy. Aortic root replacement was combined with other techniques for various disorders, including tunnel LVOT obstruction, ventricular septal defect (VSD)-aortic insufficiency complex, neoaortic insufficiency following arterial switch procedure, and subvalvular stenosis following correction of type B interruption of the aortic arch (IAA) with VSD (IAA-B/VSD). RESULTS: The mean follow up was 1.7 +/- 1.0 years (range 44 days to 4.1 years). Total follow up time was 67.8 patient-years. Two patients, both after repair of interrupted aortic arch, died intraoperatively (4.9%). There was no late mortality. Two patients were reoperated on (5.1%), one for autograft insufficiency due to cuspal perforation and one for right ventricular outflow tract stenosis at the distal anastomosis. Thirty-eight patients (97%) are currently in NYHA class I; one child with a preoperatively poor left ventricular function did not improve and is in class II. At the latest echocardiographic follow up, neoaortic regurgitation was absent in 19% of patients, trivial in 69% and mild in 11%. Homograft insufficiency was absent in 64%, trivial in 31% and mild in 6%. All mean gradients for both autograft and homograft were < 15 mmHg. CONCLUSIONS: The Ross operation can be performed with good results in infants and children with different forms of LVOT obstruction and aortic insufficiency, though aortic stenosis following IAA-B/VSD repair poses a surgically difficult problem.     

Multicenter study of stentless valve replacement in the small aortic root

OBJECTIVE: A clinical study was conducted to evaluate the results of stentless porcine valves in patients with a small aortic root (19- and 21-mm aortic anulus). METHODS: Of 567 patients, from 4 surgical institutions, 171 patients (30.1%) had a small aortic root, comprising 163 cases with calcified aortic stenosis and 8 cases with predominant valvular insufficiency. Sixty patients had associated mitral or coronary lesions. Mean age was 72 +/- 4.2 years. Forty-seven patients with a small aortic root had a 19-mm anulus, and 124 patients had a 21-mm anulus. The body surface area was, respectively, 1.55 +/- 0.2 m2 and 1.78 +/- 0.45 m2. Hemodynamic evaluation of the stentless valve comprised serial measures of mean gradients, effective orifice area, and left ventricular mass reduction. Complication rates for secondary events were evaluated over a 6-year period. RESULTS: The hospital mortality rate was 3.5%. The mean gradients after the first year were 9 +/- 2 mm Hg and 6 +/- 1.7 mm Hg in patients with a 19-mm and a 21-mm anulus, respectively. Effective orifice area was 1.45 +/- 0.3 cm2 and 1.72 +/- 0.4 cm2. Gradients and surfaces remained stable throughout the study period. Aortic regurgitation was zero to trace. Left ventricular mass at discharge and at 1 year were, respectively, 296 +/- 127 g and 215 +/- 102 g for patients with a 19-mm anulus and 281 +/- 75 g and 236 +/- 15 g for patients with a 21-mm anulus. CONCLUSIONS: Stentless valves are a suitable device for elderly patients with small aortic roots, which leave only mild residual obstruction.     

Aorto-left atrial fistula in prosthetic aortic endocarditis

Aortic valve endocarditis commonly leads to the formation of a root abscess, but fistulae are uncommon. The echocardiographic findings in a patient with Streptococcus viridans endocarditis of a prosthetic aortic valve associated with a fistula between the aorta and the left atrium are presented. The diagnosis was made by transthoracic echocardiography, although the transesophageal study gave higher resolution views and allowed a more confident exclusion of mitral valve involvement.     

Predictors of systemic embolism in patients with mitral stenosis. A prospective study

BACKGROUND: Most studies of the predictors of systemic embolism in patients with mitral stenosis have been retrospective. OBJECTIVE: To prospectively study factors associated with systemic embolism in mitral stenosis. DESIGN: Prospective cohort study. SETTING: University-affiliated medical institution with 3000 beds. PATIENTS: 534 consecutive patients with a mitral valve area of 2.0 cm2 or less; 132 patients were in sinus rhythm, and 402 were in atrial fibrillation. MEASUREMENTS: Nine clinical and 10 echocardiographic variables were assessed for prediction of systemic embolism over a mean (+/- SD) follow-up of 36.9 +/- 22.5 months. Diagnosis of systemic embolism was based on symptoms and signs (sudden onset of peripheral arterial ischemic or neurologic manifestations without prodromes) and on findings on computed tomography, angiography, and surgery. RESULTS: For patients in sinus rhythm, age (relative risk [RR], 1.12 [95% CI, 1.04 to 1.21]), the presence of a left atrial thrombus (RR, 37.1 [CI, 2.82 to 487.8]), mitral valve area (RR, 16.9 [CI, 1.53 to 187.0]), and the presence of significant aortic regurgitation (RR, 22.4 [CI, 2.72 to 184.8]) were positively associated with embolism. For patients in atrial fibrillation, previous embolism (RR, 3.11 [CI, 1.66 to 5.85]) was positively associated with embolism; percutaneous balloon mitral commissurotomy (RR, 0.37 [CI, 0.18 to 0.79]) was a negative predictor. CONCLUSIONS: It may be prudent to give anticoagulants not only to patients in atrial fibrillation and patients with previous systemic embolism but also to those showing a left atrial thrombus or significant aortic regurgitation on echocardiography. Early percutaneous balloon mitral commissurotomy may also help prevent systemic embolism in patients with mitral stenosis.     

The usefulness of Doppler echocardiography in the preoperative assessment of valvulopathies. A comparison with the hemodynamic and surgical findings

The Doppler echocardiography and cardiac catheterization studies of all patients who underwent valvular surgery in a three-year period were reviewed to assess the correlation between the estimated severity of valvular disease by both methods. Two-hundred and thirty-five patients (group I: 140 male, age 58 +/- 12; 95 female, age 60 +/- 13) underwent both studies within 6 months. There was agreement on estimation of severity of valve lesions in 140 of 162 patients with aortic valve disease (93% of stenosis, 82% of regurgitations and 79% of mixed lesions), in 58 of 80 patients with mitral valve disease (83% of stenosis, 76% of regurgitations and 33% of mixed lesions) and in 10 of 16 patients with prosthetic valve disfunction. The correlation between both methods was significantly lower in mixed mitral lesions than in the remaining native valve lesions (p < 0.05). Significant disagreement occurred in 4 cases of aortic valve disease, four of mitral valve disease and five of prosthetic disfunction. When disagreement was present, Doppler often underestimated the severity of the disease. Disagreement was more frequent in patients with combined aortic and mitral disease. According to the surgical conclusions cardiac catheterization provided a diagnostic profit in the assessment of the disease severity in 8, 11 and 22% of cases of aortic and mitral valve disease and prosthetic valve disfunction, respectively. Coronary artery disease was present in 19% of patients who underwent coronary arteriography. One-hundred and two patients (group II: 44 m, 48 +/- 15; 58 f, 53 +/- 11) underwent surgery without previous cardiac catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long term growth arrest of human Tenon''s fibroblasts following single applications of beta radiation

Aortic stenosis (AS) is a major risk factor for perioperative cardiac events in patients undergoing noncardiac surgery. We previously showed that selected patients with AS who were not candidates for, or refused, aortic valve replacement could undergo noncardiac surgery with acceptable risk. We extended our previous experience over a subsequent 5-year period by retrospectively analyzing the perioperative course of all patients with severe AS (aortic valve area index < 0.5 cm2/m2 or mean gradient > 50 mm Hg), determined with Doppler echocardiography or cardiac catheterization, who underwent noncardiac surgery. Nineteen patients underwent 28 surgical procedures: 22 elective and 6 emergency. The types of these procedures were 12 orthopedic, 6 intraabdominal, 4 vascular, 4 urologic, 1 otolaryngologic, and 1 thoracic. Mean age was 75 +/- 8 years. Of the 19 patients, 16 (84%) had > or = 1 symptom: dyspnea, angina, syncope, or presyncope. Mean left ventricular ejection fraction was 61 +/- 11%. The type of anesthesia was general in 26 procedures and continuous spinal in 2. Intraarterial monitoring of blood pressure was used in 20 of the 28 surgical procedures. Intraoperative hypotensive events were treated promptly, primarily with phenylephrine. In all cases the anesthesia team was aware of the severity of the AS and integrated this into the anesthetic plan. Two patients (elective operation in 1 and emergency in 1) had complicated postoperative courses and died. There were no other intraoperative or postoperative events in any of the other patients. Although aortic valve replacement remains the primary treatment for patients with severe AS, selected patients with severe AS, who are otherwise not candidates for aortic valve replacement, can undergo noncardiac surgery with acceptable risk when appropriate intraoperative and postoperative management is used.     

Treatment of the aortic valve and ascending aorta. The significance of reconstructive methods on the aortic root

BACKGROUND AND OBJECTIVE: The standard surgical repair of disease of the aortic valve and the ascending aorta has been combined replacement, which includes the disadvantage of inserting a mechanical valve. We have investigated an individualized approach which preserves the native valve. PATIENTS AND METHODS: Between October 1995 and October 1997, a consecutive total of 101 patients (72 men, 29 women, aged 21-83 years) underwent operations for disease of the ascending aorta: aortic dissection type A in 34 patients, aneurysmal dilatation in 67. Dilatation of the aortic arch was associated with aortic regurgitation in 58 patients. There were 11 patients with aortic valve stenosis or previously implanted aortic valve prosthesis among a total of 46 whose aortic valve was replaced (group II). Supracommissural aortic replacement with a Dacron tube was performed in 16 patients (group I) with normal valve cusps and an aortic root diameter < 3.5 cm. In 28 patients with an aortic root diameter of 3.5-5.0 cm the aortic root was remodelled (group III). Resuspension of the native aortic valve was undertaken in 11 patients with aortic root dilatation of > 5.0 cm (group IV). RESULTS: Operative intervention was electively performed in 72 patients, without any death. Of 29 patients operated as an emergency for acute type A dissection four died (14%). In 55 of the 58 patients with aortic regurgitation in proved possible to preserve native aortic valve (95%). In the early postoperative phase and after an average follow-up time of 11.8 months, transthoracic echocardiography demonstrated good aortic valve function, except in one patient each of groups III and IV who developed aortic regurgitation grades I or II. CONCLUSION: The described individualized approach makes it possible to preserve the native aortic valve in most patients with aortic regurgitation, at a low risk. Follow-up observations so far indicate good results of the reconstruction.     

Substrate specificity of human prolyl-4-hydroxylase

BACKGROUND: The mechanism responsible for the forward blood flow associated with external chest compression is still controversial. Evidence for both blood flow caused by direct cardiac compression and blood flow generated by a general increase in intrathoracic pressure has been found in experimental as well as clinical studies. No data are available concerning the mechanism causing forward blood flow in hypothermic patients undergoing cardiopulmonary resuscitation. Therefore, echocardiographic findings during external chest compression in seven hypothermic arrest victims are reported. METHODS: All transesophageal echocardiographic studies performed at the Anaesthesia department between 1994 and 1997 were reviewed and seven hypothermic patients with transesophageal echocardiography performed during cardiopulmonary resuscitation were identified. RESULTS: An open mitral valve or a circumferential reduction in aortic diameter during the compression phase was found in four of seven patients, indicating that primarily an increase in intrathoracic pressure (thoracic pump mechanism) generated forward blood flow. In three patients, mitral valve closure during external chest compression indicated that direct cardiac compression (cardiac pump mechanism) contributed to forward blood flow. Two patients studied during active compression-decompression cardiopulmonary resuscitation demonstrated enhanced right ventricular filling and aortic valve opening during active decompression of the thorax. CONCLUSIONS: In contrast to normothermic arrest victims, an open mitral valve during external chest compression is a common finding during hypothermia, indicating that thoracic pump mechanism is important for forward blood flow during cardiopulmonary resuscitation in hypothermic arrest victims. Aortic valve opening in two hypothermic arrest victims suggests forward blood flow also during active decompression of the thorax with the Cardiopump.     

Normal echocardiographic characteristics of the Sorin Bicarbon bileaflet prosthetic heart valve in the mitral and aortic positions

Doppler echocardiographic characteristics of normally functioning Sorin Bicarbon prostheses were prospectively assessed in 226 consecutive patients (135 male and 91 female patients, mean age 61 +/- 10 years) with 233 valves in the mitral (n = 67) and aortic (n = 166) positions whose function was considered normal by clinical and echocardiographic evaluation. Patterns of "normal" transprosthetic leakage were assessed with transthoracic echocardiography in all valves and with transesophageal echocardiography in six selected mitral valve prostheses. For the mitral valve prostheses, we found that peak and mean gradient, as well as pressure half-time, were not significantly different in either the 25 or the 31 mm valves (median values from 15 to 10 mm Hg, from 4 to 4 mm Hg, and from 70 to 83 ms; p = Not significant for all). On transthoracic study, 12 patients (17%) with a Sorin Bicarbon valve in the mitral position showed minimal transprosthetic leakage. On transesophageal study, all patients showed a transprosthetic leakage whose spatial distribution had a complex pattern: in planes orthogonal to the leaflet axis, two to four jets arising from the hinge points and converging toward the center of the valve plane could be visualized; in planes parallel to the leaflet axis, there were three jets, the two lateral ones diverging and the central one perpendicular to the valve plane. For the aortic valve prostheses, there was a significant decrease in transprosthetic gradients and an increase in effective orifice areas as prosthesis size increased. Peak and mean gradients decreased from a median value of 25 and 13 mm Hg in the 19 mm valves to 9 and 5 mm Hg in the 29 mm valves, respectively. Effective prosthetic valve area calculated with the continuity equation increased from a median value of 0.97 cm2 for the 19 mm size valves to 3.45 cm2 for the 29 mm size. With analysis of variance, effective prosthetic aortic valve area differentiated various valve sizes (F = 40.9, p < 0.0001) better than peak (F = 10.3, p < 0.0001) or mean (F = 8.04, p < 0.0001) gradients alone did. Furthermore, effective prosthetic aortic valve area correlated better than peak and mean gradients with prosthetic size (r = 0.76, r = -0.45, and r = -0.39, respectively). On transthoracic study, 109 patients (66%) showed minimal transprosthetic leakage. These normal values, obtained in a large number of patients with normofunctioning mitral and aortic Sorin Bicarbon valves, may help to identify Sorin Bicarbon prosthesis dysfunction.     

Midterm results of balloon dilation of congenital aortic stenosis: predictors of success

OBJECTIVES: We evaluated patient and procedural characteristics that influence the midterm success of balloon dilation of congenital aortic stenosis. BACKGROUND: Balloon dilation is a new treatment for congenital aortic stenosis. Factors that influence midterm success are unknown. METHODS: We performed a retrospective review of 148 children >1 month old who underwent balloon dilation for aortic stenosis. RESULTS: Balloon dilation was successful in 87% of patients, with a procedural mortality rate of 0.7%. The average immediate peak to peak gradient reduction was 56.4 +/- 19.9% (mean +/- SD). Prior valvotomy was the only factor that significantly reduced the immediate gradient reduction after dilation (47.1 +/- 21.8% vs. 57.8 +/- 19.6%, p < 0.01). Survival after dilation was 95% at 8 years. Seventy-five percent of patients were free of repeat intervention 4 years after dilation, whereas 50% remained free of repeat intervention at 8 years. Asymmetrically thick valve leaflets (risk ratio [RR] 0.17, p < 0.01) and prior aortic valvotomy (RR 0.35, p = 0.02) decreased the risk of repeat intervention. Aortic regurgitation grade > or = 3 (RR 4.27, p = 0.04) and residual gradient after dilation (RR 1.63 for 10 mm Hg, p < 0.01) increased the risk. CONCLUSIONS: The 8-year survival rate after dilation was 95% with 50% of patients free of repeat intervention. Factors that increased the risk for repeat intervention included symmetrically thin or thick aortic valve leaflets, regurgitation grade > or = 3 after dilation and a high residual gradient after dilation. The incidence of repeat intervention after dilation was high owing to its palliative nature.