A larger aortic annulus causes aortic regurgitation and a smaller aortic annulus causes aortic stenosis in bicuspid aortic valve

A bicuspid aortic valve (BAV) often causes aortic stenosis (AS) or regurgitation (AR). In 54 patients with a BAV (48 +/- 16 years), transthoracic and transesophageal echo were performed to measure aortic annulus diameter (AAD), to evaluate the severity of aortic valve disease (AVD) and to calculate the area eccentricity index (AEI) of a BAV defined as a ratio of the larger aortic cusp area to a smaller aortic cusp area. By multiple linear regression analysis, the severity of AR correlated significantly with the AAD (r = 0.38) and AEI (r = 0.35) (P < 0.05) and that of AS correlated significantly with the AAD (r =-0.40) and AEI (r = 0.34) (P < 0.05). Thirty-six patients showed anteroposteriorly (A-P) located BAVs and 18 patients showed right-left (R-L) located BAVs. The AAD was larger in A-P type than in R-L type (15 +/- 3 vs 13 +/- 2 mm/BSA, P < 0.05) and there was no difference in the age and AEI between the two groups. AR was more severe in A-P type than in R-L type while AS was more severe in R-L type than in A-P type (P < 0.05). Twenty-nine patients showed raphes. The AEI was larger in raphe (+) type than in raphe (-) type (1.83 +/- 0.53 vs 1.51 +/- 0.47, P < 0.05) and there was no difference in the AAD and severity of AVD between the two groups. In conclusion, a BAV with larger aortic annulus or A-P located will tend to cause AR while a BAV with smaller aortic annulus or R-L located will tend to cause AS.     

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文章论述主动脉夹层(AD)、主动脉壁间血肿(出血)、主动脉穿透性溃疡的影像学诊断的进展,并讨论三者的关系,提出影像学检查在诊断和鉴别诊断中具有重要的作用。     

主动脉弓去分支化术在主动脉病变中的应用

全弓置换术常作为主动脉弓部病变的首选方案,但由于其手术难度大,且高危患者常难以耐受深低温停循环,因此,去分支化术作为一种替代性手术,在高危患者中逐渐应用。在主动脉弓部瘤的患者中,联合去分支化及胸主动脉腔内修复术（Thoracic endovascular aortic repair,TEVAR）的杂交技术可降低75岁以上患者的住院死亡率。在B型主动脉夹层中,去分支化术可提供稳定的近端锚定区,避免烟囱及开窗技术所带来的手术难度,且有助减少内漏的发生。在A型主动脉夹层中,去分支化术主要有三种应用方式：预防性的行去分支化术,以为远期弓部的再次干预提供稳定近端锚定区;行升主动脉置换+主动脉弓去分支化+TEVAR术,可在无深低温停循环的条件下完成弓部修复;在全弓置换中,优先行弓部去分支化术,可降低停循环的温度要求及持续时间。主动脉弓去分支化术既可作为替代性的手术方式,也可作为传统全弓置换的改进方向,以改善患者的生存率。     

In-vitro comparison of aortic valve hemodynamics between aortic root remodeling and aortic valve reimplantation

BACKGROUND AND AIM OF THE STUDY: Valve-preserving aortic replacement has become an accepted option for patients with aortic valve regurgitation and aortic dilatation. The relative role of root remodeling versus valve reimplantation inside a vascular graft has been discussed, albeit controversially. In the present study, an in-vitro model was used to investigate the aortic valve hemodynamics of root remodeling and valve reimplantation; roots with supracommissural aortic replacement served as controls. METHODS: Aortic roots with aortoventricular diameter 21 mm were obtained from pigs. Root remodeling was performed using a 22-mm graft (group I, n = 6), or valve reimplantation with a 24-mm graft (group II, n = 7). Control roots were treated by supracommissural aortic replacement (22-mm graft; group III, n = 7). Using an electrohydraulic, computer-controlled pulse duplicator, the valves were tested at flows of 2, 4, 5, 7, and 9 I/min at a heart rate of 70 /min and a mean arterial pressure of 100 mmHg. Parameters assessed included: mean pressure gradient, effective orifice area, valve closure and regurgitant volume, and energy loss due to ejection, valve closure and regurgitation. Data were compared using ANOVA. RESULTS: There were no differences between the three groups in terms of regurgitant volume, energy loss due to valve regurgitation, or valve closure. The aortic valve orifice area was largest and systolic gradient lowest in group I at all flow rates (p < 0.001). Ejection energy loss was lowest in group I at all flow rates (9 l/min: group I, 128 +/- 21 mJ; group II, 399 +/- 46 mJ; group III, 312 +/- 27 mJ; p < 0.001). Valve closure volumes were similar in groups I and III, but significantly lower in group II at all flow rates (p = 0.047). CONCLUSION: In this standardized experimental setting, root remodeling--but not valve reimplantation--resulted in physiologic hemodynamic performance of the aortic valve with regard to orifice area, pressure gradient, and systolic energy loss.     

Echocardiographic assessment of aortic regurgitation and aortic root dilatation in bicuspid aortic valve]

Aortic regurgitation (AR) and aortic root dilatation in 29 consecutive patients with bicuspid aortic valves but without aortic root disease (20 males, and 9 females: aged 27-85 years) were studied using two-dimensional echocardiography. The normal ranges of aortic root dimensions were calculated from values of 185 normal subjects, as 95% confidence intervals. AR was observed in 17 patients by color flow mapping. In 12 of the 17 AR patients, no significant lesion of the aortic cusp was detected by two-dimensional echocardiography. These 12 AR patients were compared with 12 patients without AR. Increase in dimension of the aortic root was relatively frequent in the 12 AR patients at the aortic annulus (AA) (67 vs 17%, p < 0.05), and at the sinus of Valsalva (A1) (67 vs 17%, p < 0.05). At the ascending aorta 5 mm distal to the sinus of Valsalva (A2), the difference was not significant (58 vs 17%, p < 0.09). The 12 bicuspid AR patients without significant lesions of the aortic cusp were compared with 41 AR patients with normal tricuspid aortic valves. The frequencies of cases with increased aortic root dimension were 67 vs 46% (ns) at the AA, 67 vs 22% (p < 0.05) at A1 and 58 vs 5% at A2 (p < 0.01). Thus, aortic annular dilatation was thought to be the cause of AR in bicuspid and tricuspid aortic valves without significant lesions of the aortic cusps, and generalized dilatation of the aortic root was more frequent in bicuspid AR patients than in tricuspid AR patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term risk of aortic events following aortic valve replacement in patients with bicuspid aortic valves

Bicuspid aortic valve (BAV) is associated with ascending aortopathy predisposing to aneurysmal dilatation and dissection, even after successful aortic valve replacement (AVR). There is, however, scant evidence on which to make recommendations for prophylactic replacement of the ascending aorta at the time of AVR. The medical records of patients who underwent AVR for BAV without aortic replacement or repair from 1960 to 1995 were reviewed. Follow-up was by review of the medical record and postal questionnaire. Among 1,286 patients, the mean age at operation was 58 ± 14 years. During the follow-up interval (median 12 years, range 0 to 38), there were 13 documented aortic dissections (1%), 11 ascending aortic replacements (0.9%), and 127 documented cases of progressive aortic enlargement (9.9%). Fifteen-year freedom from aortic dissection, enlargement, or replacement was 89% (95% confidence interval [CI] 87% to 91%) and was lower in patients with documented aortic enlargement at the time of AVR (85%, 95% CI 81% to 89%) compared to those whose aortic dimensions were normal (93%, 95% CI 90% to 96%) (p = 0.001). Multivariate predictors of aortic complications included interval (subsequent) AVR (hazard ratio [HR] 3.5, 95% CI 2.3 to 5.4, p <0.001), concomitant coronary artery bypass grafting (HR 2.6, 95% CI 1.7 to 4.0, p <0.001), enlarged aorta (HR 1.8, 95% CI 1.3 to 2.6, p = 0.001), and history of tobacco abuse (HR 1.8, 95% CI 1.2 to 2.6, p = 0.003). Aortic dilatation did not predict mortality. In conclusion, despite a true risk for aortic events after AVR for BAV, the occurrence of aortic dissection was low. Any incremental surgical risk imposed by prophylactic replacement of the ascending aorta must be equally low.     

Detection and quantification of aortic regurgitation during aortic valvuloplasty

The degree of aortic regurgitation, before and after balloon aortic valvuloplasty, was assessed in 32 patients, using double indicator dilution curves: a) the forward curve was obtained by dye injection into the left ventricle and sampling in the aorta; b) the regurgitant curve was obtained by dye injection in the aorta and sampling in the left ventricle. A regurgitant index (RI) was calculated by obtaining the ratio of the areas of the triangles from regurgitant and forward curves. Eight-five percent of the patients were 70 years or older. After valvuloplasty, aortic valve area increased from 0.5 +/- 0.3 cm2 to 0.7 +/- 0.3 cm2 (P = .0002) while left ventricular to aortic gradient decreased from 77 +/- 32 to 51 +/- 24 (P = .0001). RI did not significantly change in 58% of patients, increased in 25%, and decreased in 15.2%. We conclude that in most patients undergoing aortic valvuloplasty, regurgitation does not change after the procedure. In some patients it may increase significantly, and in a few it may even decrease. Indicator dilution curves technique seems to provide a sensitive, accurate, and reproducible method to detect and quantify aortic incompetence before and after valvuloplasty.     

A rare form of aortic arch anomaly: left aortic and right descending aortic arch

Among aortic arch anomalies, the circumflex aortic variety, involving left aortic and right descending aortic arch, is a rare situation. Two children were recently sent to the CCML for signs of tracheobronchial compression leading to the discovery of this anomaly. The younger child, aged 2 months, had been intubated since birth, and angiography presented a constrictive form of the disorder due to the presence of a small arterial canal linking the pulmonary tree to an aberrant right subclavian artery arising from a voluminous Kommerel diverticulum. Removal of the obstacle was achieved by section of the arterial channel approached via a right posterior thoracotomy. The second patient, aged 7 years, had chronic bronchopneumonia with severe obstructive syndrome. Multislice CT investigation with three-dimensional reconstruction showed obstruction at two levels: the first concerned the lower part of the trachea related to the posterior transverse segment of the aortic arch; the more severe second obstruction was due to a vascular pinch formed by the descending aorta and the right pulmonary artery. Improvement in functional signs with time reported by the parents had led to temporisation in this case. In adults this anomaly is often a fortuitous finding during radiological investigations performed for slight functional signs. In all cases of aortic anomalies and associated lesions, the importance of precise and thorough investigation using modern radiological techniques must be stressed.     

Quadricuspid aortic valve with severe aortic regurgitation

Quadricuspid aortic valve is a rare congenital anomaly that usually presents with aortic regurgitation. Its importance, however, lies in its association with coronary abnormalities, which may lead to surgical catastrophe, if not diagnosed pre-operatively. This report describes a case of quadricuspid aortic valve detected incidentally during routine pre-operative transesophageal echocardiography.     

Single-stage treatment of aortic coarctation and aortic valve disease

Surgical management of thoracic aortic coarctation associated with severe aortic valve disease is difficult in most cases. As staged procedures are associated with a higher rate of morbidity and mortality, simultaneous operative management of both lesions is desirable. From 1997 to 2001, 9 patients (8 males and 1 female with a mean age of 30.1 +/- 10.4 years) with this condition underwent simultaneous ascending aorta-infrarenal abdominal aorta bypass graft and aortic valve replacement. One patient died from failure of the extracorporeal circulation during the operation. Another patient suffered from partial intestinal obstruction in the early postoperative period but was successfully treated. The underlying pathology was successfully corrected in the 8 surviving patients, whose blood pressure in the upper limbs was reduced while that in the lower limbs rose. Being easier to manage, the single-stage approach with extraanatomic bypass is safe and effective for managing this aortic complication.     

Extra-anatomic aortic bypass for treatment of atypical aortic coarctation

Background The conventional extra-anatomic bypass is originated from the axillary’s artery and the graft size is often limited due to the small diameter of axillary’s artery. Extra-anatomic bypass graft originating from ascending aorta can improve the graft size and distal perfusion, but need sternotomy which might have higher operative risks compared with axillo-femeral bypass. We summarize our experiences of extra-anatomic bypass from ascending aorta for atypical aortic coarctation. Methods Between January 2005 and February 2008, 5 women aged from 18 to 64 years underwent extra-anatomic bypass from ascending aorta to abdominal aorta or iliac artery bypass for treatment of atypical aortic coarctation. Preoperatively, all patients had hypertension and needed anti-hypertensive medications. Systolic blood pressure was 151 ± 9 mmHg. Ankle pressure index (API) were 0.60 ± 0.23 in left and 0.56 ± 0.23 in right. Average systolic pressure gradient of aortic stenosis was 76 ± 18 mmHg. Three patients underwent concomitant cardiac operation, including coronary artery bypass grafting, Bentall procedure and atrial septal defect repair. Results There was no hospital and late mortality during 58 ± 15 months follow-up (range from 44 to 81 months). Postoperative systolic blood pressure was reduced to 126 ± 11 mmHg at the time of discharge. All patients maintained normal blood pressure without medication during follow-up. API was improved to 1.12 ± 0.24 in left and 1.17 ± 0.25 in right (compared with preoperative data, P < 0.05). Follow-up computer tomography showed patency in all grafts. Conclusions Surgical treatment of atypical aortic coarctation with extra-anatomic bypass originating from ascending aorta alleviates hypertension and low limb ischemia.     

Cross-sectional echocardiographic characterization of aortic obstruction. 1. Supravalvular aortic stenosis and aortic hypoplasia

Cross-sectional echocardiographic and cineangiographic studies of the left ventricular outflow tract and ascending aorta were performed in five patients with supravalvular aortic stenosis (four hourglass and one hypoplastic). Visualization of the area of obstruction was possible in each patient using the cross-sectional system. In each case the echocardiographically determined diameter at the level of obstruction was within 3 mm of the similar angiographic value. Assessment of the extent of the lesion was possible in four of five cases. In three of these four cases the echocardiographic measurement was within 5 mm of the angiographic measurement while in the fourth the obstruction was felt to involve the total ascending aorta by both techniques. Determination of percent decrease in LVOT diameter from the aortic anulus to the level of obstruction was useful in defining obstruction and estimating severity. Cross-sectional echocardiography is a valuable noninvasive method for evaluating the ascending aorta in patients with supravalvular aortic stenosis.     

Evaluation of aortic wall distensibility by aortic pressure-dimension relation: effects of nifedipine on aortic wall

The relation between aortic pressure and dimension was studied before and after nifedipine infusion in eight anaesthetised dogs. An electromagnetic flowmeter was positioned in the proximal ascending aorta and one pair of ultrasonic dimension gauges attached to the thoracic aorta. A Millar micromanometer was positioned just below the dimension gauges. A constrictor was placed around the thoracic aorta distal to the dimension gauges to produce an abrupt rise in aortic pressure for 15 s. After complete recovery nifedipine (0.75 micrograms.kg-1.min-1) was infused for 10 min and the same procedure repeated. The ratio (delta D:delta P) of the difference (delta D) between maximum and minimum dimensions (D) to the pulse pressure (delta P) and the percentage distensibility (delta D/delta P/minimum D) were decreased significantly after aortic constriction (0.037(0.013) to 0.019(0.004) mm.mmHg-1 and 0.247(0.075) to 0.121(0.033)%.mmHg-1, p less than 0.01, respectively), suggesting that these indices depend on afterload. Beat to beat mean pressure-dimension relations during the release of aortic constriction showed a convex upward curve and was fitted by an exponential function with a high correlation coefficient (r = 0.99). The slope of this relation was significantly reduced after nifedipine compared with before nifedipine (379(83) to 330(119) mmHg.cm-1, p less than 0.05), suggesting an increase in aortic distensibility by nifedipine. When mean aortic pressure or stroke volume before and after nifedipine was compared at the same mean dimension, which was reduced by 5% of the control mean dimension, stroke volume increased to 128%(p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)