主动脉根部外科解剖及其与毗邻结构关系

目的：测量主动脉根部不同高度的口径大小，并观察主动脉窦与邻近结构的关系。方法：用30例正常成人甲醛固定心脏标本，测量主动脉根部不同高度的口径和主动脉瓣的大小，观察主动脉窦与邻近结构的关系。结果：（1）主动脉窦中部（Sinus)＞主动脉窦管结合部上1cm(STJ1)＞主动脉窦管结合处（STJ0）＞主动脉瓣环基底（Base）。经方差分析检验，P＜0．05，说明主动脉根部4个高度口径大小的差别具统计学意义。（2）主动脉瓣的瓣高、瓣附着缘长和瓣游离缘长的测量结果显示。（3）二尖瓣前瓣中轴线与主动脉窦的关系显示，二尖瓣前瓣中轴线86．6％位于左冠状动脉窦与无冠状动脉窦之间。（4）右心房主动脉隆凸与主动脉窦的关系显示，右心房主动脉隆凸由无冠状动脉窦形成者占73．3％，由无冠状动脉窦和右冠状动脉窦共同形成者占26．7％。（5）左、右肺动脉瓣交界点与主动脉窦的关系显示，左、右肺动脉瓣交界点对向左、右冠状动脉窦之间者占80％。结论：测量结果有助于心外科手术的开展。     

Aortic valve sparing operations: an update

Background. Aortic valve sparing operations in patients with ascending aorta and/or aortic root aneurysms have been performed for a decade in our institution. Initially only patients with normal aortic valve leaflets had these operations, but more recently we utilized them in patients with prolapse of a single leaflet and in those with a bicuspid aortic valve. This article is an update on the clinical results of these operations.

Methods. From May 1988 to December 1997, 126 patients with ascending aorta and/or aortic root aneurysms and aortic insufficiency underwent replacement of the ascending aorta with reconstruction of the aortic root and preservation of the native aortic valve. There were 85 men and 41 women, with a mean age of 54 years (range, 14 to 84). Thirty-two patients had the Marfan syndrome; 17 patients had acute and 10 had chronic type A aortic dissection; 23 had a transverse arch aneurysm; 26 had coronary artery disease, and 8 had mitral regurgitation. The aortic valve sparing operation consisted of simple adjustment of the sinotubular junction in 33 patients, adjustment of the sinotubular junction and replacement of one or more aortic sinuses in 60, and reimplantation of the aortic valve in a tubular Dacron (C.R. Bard, Haverhill, PA) graft in 33. Fifteen patients also had repair of aortic leaflet prolapse. Only 4 patients had a bicuspid aortic valve.

Results. There were 3 operative deaths due to cardiac failure. Patients were followed from 2 to 117 months, with a mean of 31. There were 11 late deaths: 7 cardiovascular and 4 from unrelated causes. The actuarial survival was 72 ± 8% at 7 years. Two patients required aortic valve replacement; the freedom from aortic valve replacement was 97 ± 2% at 7 years. Doppler echocardiography revealed absent, trivial or mild aortic insufficiency in most patients; only 9 patients had moderate aortic insufficiency.

Conclusions. Aortic valve sparing operations are feasible in most patients with ascending aorta and/or aortic root aneurysms who have normal or near normal aortic leaflets. The functional results of the repaired aortic valve are excellent, and the repair appears to be durable.     

The myth of the aortic annulus: the anatomy of the subaortic outflow tract

Surgical repair of the small aortic root is limited in part by the very structure of the outflow tract from the left ventricle. The root is not constructed on the basis of a ringlike annulus supporting the leaflets of the aortic valve. The only truly circular structure within the outflow tract is the junction of the aortic wall with the underlying ventricular structures, themselves partly muscular and partly fibrous. This circular ventriculoarterial junction is crossed by the semilunar attachments of the leaflets of the aortic valve, producing an interlinking arrangement between the expanded aortic sinuses and three triangles of fibrous tissue placed beneath the apexes of the commissures between the valve leaflets. The triangles form extensions of the left ventricle that are related, in part, to the pericardial cavity surrounding the heart. The arrangements of the attachment of the leaflets in malformed valves with two (or only one) effective leaflets are highly abnormal, although these valves are usually produced on the template of three aortic sinuses. The valve with two leaflets rarely gives problems during childhood. In valves producing "critical stenosis", there is usually only one effective leaflet, a condition due to incomplete liberation of two of the anticipated three commissures. Detailed study shows that, in these malformed hearts, the attachment of the leaflets is much more annular than in normal valves, with inadequate formation of the fibrous triangles.     

Aortic root reconstruction with preservation of native aortic valve and sinuses in aortic root dilatation with aortic regurgitation.

BACKGROUND: We assessed the results of a modified technique for aortic root reconstruction including preservation of the native aortic valve and sinuses. METHODS: A modified technique for reconstruction of the aortic root was devised in which the native aortic sinuses are preserved and remodeled, the diameter of the sinotubular junction is reduced, the ventriculoaortic junction is reinforced with a Dacron prosthesis, and the coronary ostia are reimplanted. Since January 1995, this modified operative technique was performed in 13 patients with a mean age of 54 +/- 21 years. The median grade of aortic regurgitation was 3; in 10 patients it was caused by dilatation of the sinotubular junction, and 3 had additional annuloaortic ectasia. RESULTS: The aortic crossclamping time was 61 +/- 18 minutes. In-hospital mortality was 2 of 13 (15. 3%) patients, both deaths being related to complications of aortic dissection. In 1 patient aortic regurgitation increased to grade 3, necessitating aortic valve replacement. At a mean follow-up of 2.1 years, the remaining 10 patients had stable aortic valve function with a median grade of regurgitation of 1. The mean New York Heart Association functional class was 1.2. CONCLUSIONS: Aortic root reconstruction with preservation of the native aortic valve and sinuses allows symmetric reconstruction of the aortic sinuses and adaptation of the diameters of the sinotubular and ventriculoaortic junctions, thus optimizing aortic valve function. Moreover, it prevents contact of the aortic valve leaflets with the Dacron graft, which may enhance the durability of the repair.     

Flow patterns in the aortic root and the aorta studied with time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging: implications for aortic valve-sparing surgery

OBJECTIVE: Sparing the aortic valve has become a surgical option for patients who require repair of aortic root ectasia and have normal valve leaflets. Surgical approaches to valve sparing differ with regard to preservation of the native sinuses of Valsalva. The role of the sinuses and the importance of maintaining them remain controversial. METHODS: By using a time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging technique, aortic root and aortic blood velocity data were acquired from 2 patients with Marfan syndrome 6 months after aortic valve-sparing surgery with straight Dacron grafts and contrasted with data from 6 normal volunteers. RESULTS: In normal aortas vortical blood flow became apparent in the individual sinuses after peak systole. The vortices filled the available space behind the valve leaflets and persisted until diastole, expanding and moving inward during aortic valve closure. In contrast, no vortices were observed in the postoperative patients with Marfan syndrome with negligible sinuses. CONCLUSIONS: Changes in supravalvular flow accompany loss of sinus architecture. Whether the presence, size, and velocity of supravalvular vortices affects the function or durability of the preserved aortic valve remains to be studied.     

Clinical introduction of a novel prosthesis for valve-preserving aortic root reconstruction for annuloaortic ectasia

OBJECTIVE: Most patients with annuloaortic ectasia are young. They are at risk for complications related to a lifetime of anticoagulation when composite grafts containing mechanical valves are used for reconstruction. The majority of patients have near normal valve cusps. Valve-preserving techniques have been developed to maintain valve function and avoid anticoagulation. The eddy currents occurring within the sinuses of Valsalva in the natural aortic root have been shown to be important in the smooth, gradual, and gentle closure of the valve. Compliance of the sinuses is important in reducing stress in the leaflets. A novel ascending aortic prosthesis with "built in" compliant sinuses (Robicsek-Thubrikar graft) was developed for clinical aortic root replacement. METHODS: Woven Dacron tubes were used to make the prostheses. Three precisely measured square pieces were cut to make the expandable, individual sinuses. Sewing the individual neo-sinuses to a scalloped end of the Dacron tube graft created the neo-sinotubular junction and sinotubular ridge. Five patients with annuloaortic ectasia underwent valve-preserving aortic root reconstruction. RESULTS: All intraoperative transesophageal echocardiographic images after the valve-preserving procedure showed a normal appearing root with 10% radial expansion of each sinus in systole. The space between the cusps and neo-sinus wall in systole was normal. No patient has more than mild aortic regurgitation. CONCLUSIONS: Valve-preserving aortic root reconstruction with a novel Dacron prosthesis with compliant "built in" sinuses re-establishes normal aortic root geometry with near normal valve motion. This may enhance the durability of the valve-preserving operation.     

How to repair an acquired Gerbode defect using an aortic root xenograft

A 74-year old female patient presented with a 3-week history of fever, general weakness, and later developed complete heart block. On admission, the patient was febrile (temperature of 39°C) and tachypnoeic (respiratory rate of 29/min) with oxygen saturation of 95% on 2 L of oxygen. Her heart rate was 60 beats/min (VVI pacing), arterial blood pressure was 135/60 mm Hg and the Glasgow Coma Scale was 15. On chest auscultation, she had a harsh systolic murmur over her left precordium and bilateral rales. Blood tests demonstrated moderate anemia (hemoglobin of 95 g/L), leucocytosis (white blood cell count of 13.13 x 10^9/L), hypoalbuminemia (albumin concentration of 18 g/L), normal liver function tests and creatinine clearance of 45 ml/min. Computed tomography aortography demonstrated an irregular mass arising from the aortic root that extended into the right atrium (RA) and a fistulous tract (the Gerbode defect) between the left ventricular outflow tract (LVOT) and the right ventricle (RV). Transoesophageal echocardiography showed large vegetation in the RA and left to right cardiac shunt through the Gerbode defect from the LVOT to the RA and the RV. Using cardiopulmonary bypass, the patient underwent resection of the aortic cusps, debridement of the aortic root, septal and anterior leaflets of the tricuspid valve, and the membranous septum. The Gerbode defect was closed with an autologous pericardial patch, then a sliding annuloplasty of the septal leaflet of the tricuspid valve was performed. Finally, the aortic root was replaced with a 23 mm Freestyle xenograft.     

Aortic valve reconstruction in the young infants and children

Considering the structure and function of the aortic root, changes in the aortic valve leaflets and changes in the geometry of the aortic root are the two primary causes of aortic valve dysfunction. In adults, aortic valve sparing reconstruction has a long history beginning in the 1970s, where tensor fascia was used for leaflet repair in patients with isolated aortic regurgitation and ascending aortic replacement was used in patients with ascending aortic aneurysms or aortic ectasia. Subsequent progress in the 1980s and 1990s led to pericardial leaflet replacement and aortic root re-implantation and remodeling. However, it has not been until the last decade that these concepts and techniques have been applied in younger patients focusing on the conotruncus, valvar apparatus, sino-tubular junction, and ascending aorta.     

Coronary flow obstruction in percutaneous aortic valve replacement. An in vitro study.

OBJECTIVE: Coronary flow obstruction is a serious complication reported in percutaneous aortic valve replacement. In an in vitro study of porcine hearts, the effects of valved stent implantation on coronary artery flow were studied with the native valve's leaflets intact and excised. METHODS: The right and left main coronary arteries of porcine hearts were dissected 20mm distal to the aortic root and directed into lengths of latex tubing leading to collection flasks. The ascending aorta was cut proximal to the brachiocephalic trunk, cannulated, and attached to a constant-head water supply. After steady flow was achieved, the flow rate from each coronary artery was measured. In Group A (n=10), a tubular pericardial valve sutured into a cylindrical, cobalt-nickel stent was deployed orthotopically using a valvuloplasty balloon catheter. In Group B (n=10), the native leaflets were removed before similar valve deployment. Coronary flow measurements were repeated post-implantation. RESULTS: In Group A, valve implantation resulted in a significant decrease in both left and right coronary flows. In Group B, no significant change in either right or left coronary flow was found after valve placement. CONCLUSION: Implantation of a percutaneous valved stent in the orthotopic position with the native valve in place causes coronary ostial obstruction. This problem highlights the need for modified stents that are designed for implantation in patients with non-retracted, fibrotic, or calcified leaflets.     

Aortic root dilatation may alter the dimensions of the valve leaflets

Objective: Valve-sparing surgery can be used in patients with dilated aortic roots and aortic insufficiency (AI) but has not become a common practice, in part because the spared valve may be incompetent. Our goal was to study how the dimensions of the aortic root and leaflets have changed in such patients. Methods: Fourteen patients with dilated aortic root and AI were examined by transesophageal echocardiography. The annulus diameter, sinotubular junction (STJ) diameter, sinus height, leaflet free-edge length, and leaflet height were measured. Correlations among these dimensions and with the AI grades were explored. Measurements were also made in 19 normal human aortic valves from silicone molds. Results: There was no evident change in the average diameter of the annulus between the normal valves and those in the dilated aortic roots. The STJ diameter was obviously increased in the dilated aortic roots; the aortic sinuses also appeared to be taller and the leaflets larger than normal. The leaflet free-edge length, the leaflet height, and the sinus height were found to increase with the dilated STJ diameter. The degree of AI was not found to correlate well with any of the dimensions measured. Conclusions: The dimensions of the leaflets may change parallel to aortic root dilatation with AI. Therefore, during valve sparing, it may be necessary to correct both the dilatation of the root and the leaflet free-edge length to achieve a competent valve.     

An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta.

A number of patients who require an operation for complications of annuloaortic ectasia, such as aortic incompetence or aneurysm of the aortic root (or both), have normal aortic valve leaflets. We have treated these patients by excising the aneurysmal portion of the ascending aorta and sinuses of Valsalva but by leaving the aortic valve leaflets and some arterial wall attached to the left ventricular outflow tract. The aortic valve is reimplanted inside a collagen-impregnated tubular Dacron graft, similar to what is done for implantation of an aortic valve homograft. The coronary arteries are also reimplanted. This operation was performed in 10 patients. All patients had annuloaortic ectasia and five had the stigmata of Marfan syndrome. Four patients had acute aortic dissection. There were no operative deaths, but one patient required composite replacement of the aortic valve and ascending aorta because of persistent aortic incompetence. Postoperative Doppler echocardiography revealed normal aortic valve function in six patients and mild incompetence in three. The preliminary results of this new operation are encouraging. Further investigation is necessary to establish the best size, shape, and type of material that should be used to replace the aortic root while preserving the aortic valve.     

Aortic root remodeling in atheromatous aneurysms: the role of selected sinus repair.

OBJECTIVE: Atheromatous ascending aortic aneurysms (AAA) frequently present with aortic regurgitation (AR) from dilatation of the sino-tubular junction (STJ) and extension of the pathological process into the root. Experience suggests that root dilatation begins in the non-coronary, then right coronary sinus. Rather than employ aortic root replacement or the David procedure, we have elected to replace the ascending aorta and remodel the STJ and involved sinuses. We studied the outcome after selective sinus replacement in 29 consecutive AAA patients between 1995 and 2001. METHODS: There were nine male and 20 females. Age ranged from 47 to 79 years (mean 67.5). Seven had arch aneurysms and four coronary artery disease. Nineteen were NYHA III or IV. Grade of AR was IV in 20, III in five and II in four. The STJ was dilated >50% of annulus diameter in each case (5.3-10.0 cm, mean 6.4 cm). All valves had three cusps. All patients underwent ascending aortic replacement. Seven had arch replacement and four coronary artery bypass. Seven had replacement of both right and non-coronary sinuses with re-implantation of the right coronary ostium. Twelve had replacement of the non-coronary sinus alone whilst nine had right coronary sinus replacement. One with dextrocardia had left coronary sinus replacement with ostial re-implantation. The graft size was within 2 mm of annulus size except for two patients (24 mm 12, 26 mm 11, and 28 mm six). Post operative echocardiographic studies were performed. None of the patients received anticoagulation. RESULTS: There were no hospital or late deaths and no thromboembolic or infective complications. Two patients had mild to moderate aortic regurgitation. These had a size 28 graft, which in retrospect was too large. Others had no significant regurgitation. CONCLUSIONS: The native aortic valve can be preserved in the majority of patients with AAA. Remodelling of the STJ and selective sinus replacement restores valve competence. Anticoagulation and prosthesis related complications are thereby avoided.     

Coronary arterial and sinusal anatomy in hearts with a common arterial trunk

Eighty-four specimens of common arterial trunk were studied with special reference to the arrangement of the leaflets in relation to the atrioventricular valves, the origin of the coronary arteries in relation to the arterial sinuses, and the epicardial course of the coronary arteries. Fourteen normal hearts were used for comparison. In the hearts with common arterial trunk, the location and level of the coronary artery orifices (as well as the relationship of the truncal root to the area of fibrous continuity with the mitral valve) are different from those in normal hearts. In none of the hearts with common arterial trunk (particularly the 53 hearts with three leaflets in the truncal valve) did the appearance of the truncal valve approximate that of a normal aortic valve. Among the 22 hearts with four leaflets, there was a high incidence of coronary artery orifices in opposite sinuses (17/22 or 77.3%) and a low incidence of coronary artery orifices in adjacent sinuses (2/22 or 9.1%). These results suggest that the formation of the truncal valve is independent of the formation of the coronary orifices. Its leaflets are not predestined to become part of either the aortic valve or the pulmonary valve.     

Aortic repair in Marfan's syndrome: prevention of mechanical leaflets damage

Aortic incompetence in Marfan's syndrome results from distortion or dilatation of the sinuses of Valsalva, annuloaortic ectasia or a combination of these problems. Valve leaflets in these patients are macroscopically normal in spite of aortic insufficiency. Replacement of the ascending aorta, root and aortic valve with a composite graft was, for a long time, the treatment of choice for Marfan patients. Valve-preserving procedures (remodeling or reimplantation) provide the advantages of avoiding the shortcomings of standard surgical techniques, and maintaining the functional integrity of the left ventricular (LV) outflow tract, aortic root and ascending aorta. We developed a modified valve-sparing reimplantation technique for avoiding leaflet damage. This was achieved by leaving a 'cushion' of aortic wall (8--10 mm) that, sewn on the Dacron graft, works as a 'damper' and prevents leaflets injury during the systolic opening of the valve. For final judgment of this operative method long-term results are necessary.     

Valve-sparing aortic root replacement

The aortic root has a unique 3-dimensional configuration and the distinctive function of supporting the aortic valve and blood vessels. The sinuses of Valsalva are crucial to create appropriate eddy currents that are important in initiating and coordinating aortic valve closure and promoting coronary artery blood flow. Most aneurysms in the aortic root are associated with degenerative changes in the elastic media rather than atherosclerosis. Valve-sparing root repair has become widely accepted, although the Bentall procedure remains the gold standard. Because reimplantation using the Valsalva graft allows root geometry to be retained and theoretically and practically prevents recurrent aortic valve regurgitation, it is considered the most reliable and preferred technique among various valve-sparing aortic root repair procedures.     

Sinus of Valsalva aneurysm repair with partial allograft, and 10-year follow-up

Sinus of Valsalva aneurysms are rare congenital or acquired defects that frequently are manifested by rupture into adjacent cardiac structures. Most aneurysms involve a portion of the sinus, and can be surgically treated with primary or patch closure of the defect. We present a case report of a giant aneurysm that involved the entire noncoronary sinus of Valsalva, and describe a previously unreported technique with 10-year follow-up using a partial aortic allograft to reconstruct the abnormal aortic sinus, preserving the native valve leaflets and normal sinus geometry and averting use of prosthetic materials.     

Opening and closing characteristics of the aortic valve after valve-sparing procedures using a new aortic root conduit

BACKGROUND: The durability of aortic valve-sparing procedures is negatively affected by increased leaflet stress in the absence of normally shaped sinuses of Valsalva. We compared valve motion after remodeling procedures using a standard conduit and a specifically designed aortic root conduit. METHODS: Echocardiographic studies of the aortic valve dynamics were performed in 14 patients after remodeling of the aortic root (7 standard conduits, group A; 7 new conduits, group B) and in 7 controls (group C). Opening and closing leaflet velocities and percent of slow closing leaflet displacement were measured. Root distensibility and the pressure strain of the elastic modulus were measured at all root levels. RESULTS: Root distensibility and the pressure strain of the elastic modulus were different in group A and B only at the sinuses (p < 0.001). Opening and closing leaflet velocities were not different among groups. Slow closing leaflet displacement was markedly more evident in group B patients (24.2%+/-1.9% versus 2.5%+/-1.9% in group A, p < 0.001) and similar to controls (22.1%+/-7.9%). CONCLUSIONS: The new conduit guarantees dynamic features of the aortic valve leaflets superior to those obtained with standard conduits and more similar to normal subjects.     

Aortic Valve Replacement with Stentless Porcine Bioprostheses

Aortic valve replacement with stentless porcine valve should provide superior hemodynamic results to stented porcine valve because the obstruction caused by the stent and the sewing ring is eliminated. In addition, the coronary sinuses of the recipient may allow for better dissipation of the mechanical stress to which the leaflets are subjected during diastole, thus enhancing durability of the heterograft. Aortic valve replacement with stentless glutaraldehyde-fixed aortic porcine bioprosthesis was carried out successfully in six young sheep. These animals were hemodynamically evaluated at 3 to 6 months after operation and found to have no resting gradients or any degree of aortic regurgitation. Explantation of the aortic heterograft revealed that it was well healed in the aortic root and had no evidence of any calcification. A clinical trial has been initiated and the results in the first five humans who underwent aortic valve replacement with a stentless porcine aortic bioprosthesis have been satisfactory.     

Modification of the Bentall operation using the proximal double sewing technique without excision of leaflets

We present a report on reinforcement of the proximal anastomosis during the Bentall operation. The aortic wall was excised with a 5-mm remnant, and aortic valve leaflets were preserved. Interrupted horizontal mattress sutures (2-0 Polyestel) reinforced with pledgets were placed. The composite graft was placed at the intraannular position inside of the preserved leaflets. The aortic valve leaflets were then pasted to the sewing cuff with fibrin glue. A running suture with 4-0 monofilament was placed between the remnant of the aortic wall and the peripheral side of the sewing cuff wrapped with native aortic valve leaflets.     

Rescue surgical embolectomy for fatal pulmonary embolism in patient with intracranial hemorrhage

Left ventricular outflow obstruction may result from preserving the anterior leaflet after mitral valve replacement. A 79-year-old woman, who had a mitral valve replacement with the native mitral leaflets left intact 16 years before, was admitted to our hospital with severe dyspnea due to heart failure. Echocardiography showed systolic anterior motion of preserved anterior mitral leaflet, and continuous wave Doppler detected severe left ventricular outflow tract jets during systole without mitral chordal rupture. Surgical incising of the anterior mitral leaflet through the aortic root relieved the obstruction without removing the prosthetic mitral valve.