Structural abnormalities of great arterial walls in congenital heart disease: light and electron microscopic analyses

Correlations of phenotype and genotype in relation to morphologic remodelling of the aortic root in patients with Turner's syndrome

BACKGROUND

Patients with Turner's syndrome are at risk of aortic dilation and dissection. Currently, it is not known whether such dilation is related to associated cardiovascular abnormalities, or to the genetic anomaly itself.

METHODS

We studied echocardiographically 107 patients with genetically proven Turner's syndrome, with heterogeneous underlying karyotypes, and without associated cardiac lesions. Their average age was 19.6 plus or minus 8.4 years. We compared the finding with those from 71 age-matched healthy female volunteers. The diameter of the aorta was measured at the level of the basal attachments of the aortic valvar leaflets, the sinuses of Valsalva, the sinutubular junction, and its ascending component.

RESULTS

Compared to control subjects, the patients with Turner's syndrome had larger diameters of the aorta at the level of the sinuses of Valsalva, at 23.4+/-4.8 versus 25.5+/-4.1 millimetres (p = 0.0014), the sinutubular junction, at 19.9+/-3.8 versus 23.3+/-4.1 millimetres (p < 0.0001), and the ascending aorta, at 22.3+/-4.9 versus 24.6+/-4.4 millimetres (p = 0.0011). Dilation of the sinutubular junction, found in just over one-quarter of the patients, was more common than dilation of the ascending aorta, the latter found in less than one-tenth. The patients with Turner's syndrome, therefore, presented with remodelling of the aortic root, with relative dilation of the sinutubular junction. The underlying karyotype influenced both the dimensions of the sinutubular junction (p = 0.0054), and the ascending aorta (p = 0.0064), so that patients with the karyotype 45X had larger aortas. The karyotype was the strongest predictor by multivariate analysis for dilation at both these sites (p = 0.0138 and 0.0085, respectively).

CONCLUSIONS

Dilation at the sinutubular junction is frequent in patients with Turner's syndrome, and is more common than dilation of the ascending aorta. The syndrome is associated with a remodelling of the aortic root, with prominent dilation of the sinutubular junction. There seems to be a relation between aortic dilation and the underlying genotype.

Aortic aneurysms: delayed complications of coarctation of the aorta repair using Dacron patch aortoplasty

Coarctation of the aorta is a diaphragmlike ridge narrowing the lumen of the proximal descending aorta. Although surgical repair has proven to be a successful treatment of coarctation of the aorta, immediate and delayed postoperative complications are not rare. Of particular interest is the occurrence of aneurysms after Dacron patch aortoplasty--often decades after surgery. Delayed complication rates of up to 50% have been reported. We describe the clinical-radiologic presentations of 3 late complications of Dacron patch angioplasty: aortobronchopleural fistula, leaking pseudoaneurysm, and giant descending aortic aneurysm--all successfully treated with bypass grafts. Because of the high incidence of delayed complications, lifelong surveillance is necessary. The chest x-ray may be the first clue to a delayed complication. Knowledge of radiologic findings is helpful in the detection of complications-before they become symptomatic. Transesophageal echocardiography, computed tomography angiography, or magnetic resonance imaging with multiplanar reconstruction is diagnostic.

Basal and oxidative stress-induced expression of metallothionein is decreased in ascending aortic aneurysms of bicuspid aortic valve patients

BACKGROUND

Bicuspid aortic valve (BAV) is a heritable condition that has been linked by an unknown mechanism to a predisposition for ascending aortic aneurysm. Matrix metalloproteinases have been implicated in this predisposition. Metallothionein is a poorly characterized, metal-binding protein that regulates matrix metalloproteinases and is an antioxidant known to be upregulated under oxidative stress.

METHODS AND RESULTS

To determine putative factors involved in the pathogenesis of aortic aneurysm in BAV patients, our first goal was to identify genes that are dysregulated in ascending aortic aneurysms of BAV patients compared with tricuspid aortic valve patients and nondiseased (control) donors. By microarray analysis (22,000 probe sets), 110 dysregulated genes were identified in BAV compared with tricuspid aortic valve patients and control donors; 8 were genes of the metallothionein family. Metallothionein gene expression and protein expression were significantly lower in aortic tissue and cultured aortic smooth muscle cells from BAV patients compared with control subjects. Matrix metalloproteinase-9 expression was increased in BAV aortic samples relative to controls. BAV aorta was more susceptible to oxidative stress, and induction of metallothionein under oxidative stress was reduced in BAV patients compared with control subjects.

CONCLUSIONS

These results demonstrate dysregulated metallothionein expression in ascending aortic smooth muscle cells of BAV patients that may contribute to an inadequate response to oxidative stress and provoke aneurysm formation. We hypothesize that metallothionein plays a pivotal role in the response of ascending aortic smooth muscle cells to oxidative stress cues normally involved in the maintenance of the extracellular matrix, including the regulation of matrix metalloproteinase expression.

The dilated aorta in patients with congenital cardiac defects

Many patients with congenital cardiac disease are at risk for progressive aortic dilation. The mechanisms underlying aortic dilation in this patient cohort are described, and the similarities to the pathophysiologic alterations seen in Marfan syndrome are highlighted. Indications for treatment are discussed.

Mitral regurgitation due to myxomatous degeneration combined with bicuspid aortic valve disease is often due to prolapse of the anterior leaflet of the mitral valve

BACKGROUND

This study examines the clinical, echocardiographic, surgical, and pathologic features of patients who had heart valve operations for combined congenital bicuspid aortic valve and mitral regurgitation due to degenerative disease of the mitral valve.

METHODS

A retrospective review of 1595 patients who had procedures for mitral regurgitation due to degenerative disease of the mitral valve and 1820 patients who had procedures for congenital bicuspid aortic valve disclosed 29 patients who had combined diseases.

RESULTS

The most common morphology of the bicuspid aortic valve was type 1 (fused right and left aortic cusps). Mitral regurgitation in 21 of 29 patients was caused by prolapse of the anterior leaflet, which was exceptionally large (mean height, 36.5 +/- 6.6 mm). Patients with prolapsed anterior leaflet of the mitral valve were younger (48 +/- 13 years vs 58 +/- 16 years, p = 0.01) and 95% were men. The bicuspid aortic valve was incompetent in 19 of 21, and the aortic annulus exceeded 30 mm in 20 of 21 patients.

CONCLUSIONS

Patients with combined mitral regurgitation due to myxomatous degeneration and bicuspid aortic valve disease who require operations often have a large, prolapsing anterior leaflet of the mitral valve and dilated aortic annulus with aortic insufficiency due to cusp prolapse.

Relation of coarctation of the aorta to the occurrence of ascending aortic dilation in children and young adults with bicuspid aortic valves

Children with bicuspid aortic valve (BAV) have aortic dilation that is present and progressive from birth irrespective of the functional state of the valve. There are no published data comparing aortic dilation in children with BAV with and without aortic coarctation (CoA). The objectives of this study were to (1) compare differences in aortic dimensions and rates of dilation between children with isolated BAV with those of children with BAV and CoA and (2) identify risk factors for the development of aortic dilation. Patients with BAV with CoA (group A) and without CoA (group B) were identified from our echocardiographic database (1993 to 2006). Aortic measurements at 4 levels were obtained, and z scores were compared. Criteria for exclusion were severe aortic regurgitation/stenosis, previous aortic valvuloplasty, complex left-sided cardiac disease, ventricular septal defects, and Turner, Noonan, Williams, and Marfan syndromes. There were 600 echocardiograms in 247 patients. Group A had 192 echocardiograms in 53 patients (median age 11.3 years; range 0 to 30; median follow-up 7 years), and group B had 382 in 194 patients (median age 8.7 years; range 0 to 29; median follow-up 4 years). Group B had significantly greater ascending aorta dimensions (p<0.05) and significantly faster rates of aortic dilation (p<0.0001). The ascending aorta in patients with BAV and CoA did not dilate to the same degree as in patients with isolated BAV. In conclusion, valve morphologic characteristics and function and age at CoA repair had none to minimal impact on aortic dimensions.

Management of the aortic root in adult patients with conotruncal anomalies

Conotruncal anomalies such as tetralogy of Fallot, double outlet right ventricle, truncus arteriosus, and transposition of the great arteries are a group of congenital heart defects with abnormalities of the outflow tracts and great vessels. It is common for the ascending aorta and aortic root to be significantly dilated following initial repair of the conotruncal anomaly, and little information is available on the management of this increasing problem. Although there are few case reports of aortic dissection and rupture in the literature, it appears to be rare in the setting of a conotruncal anomaly and may be related to the absence of hypertension and smoking in many of these patients. The timing of operation with regard to the size of the aortic root is difficult. In the absence of a family history of aortic dissection or aneurysm, or documented rapid growth of the ascending aorta, we proceed with replacement of the ascending aorta when the size is > or = 55 mm. When the size of the ascending aorta is 5.0-5.5, treatment is individualized depending on the associated anomalies that need to be addressed, patient comorbidities, and life expectancy. In this group of patients we consider a simple reduction ascending aortoplasty. We generally proceed with root replacement and coronary reimplantation when there is effacement of the sinotubular junction, or when there is severe dilatation of the aortic root with an intact sinotubular junction. If the ascending aorta is > or = 55 mm with an intact sinotubular junction and the sinuses are < or = 4 cm, then we use a supracoronary tube graft.

Dilatation of the ascending aorta in bicuspid aortic valve disease: a magnetic resonance imaging study

BACKGROUND

Bicuspid aortic valve disease (BAV) is increasingly recognized as a disease of the entire proximal aorta including both valvular and vascular complications. The aim of our study was to assess the dimensions of the thoracic aorta using MRI in a broad spectrum of BAV and tricuspid aortic valve disease (TAV) and to define the prevalence of the dilatation of the ascending aorta (AA) >or= 4.5 cm in severe BAV disease.

METHODS AND RESULTS

MRI studies were performed on a 1.5 T scanner in a total of 195 consecutive patients with aortic valve disease. Eighty-four aortic valves were classified as BAV and 103 as TAV. In 8 patients, classification of the aortic valve was not possible due to poor image quality. Mean diameters of the AA were significantly greater in BAV compared to TAV (4.39+/-0.85 Vs. 3.55+/-0.47 cm, P<0.0001), whereas no differences were observed in the mean diameters of the aortic arch. Diameters of the descending aorta were slightly smaller in BAV compared to TAV (2.45+/-0.43 Vs. 2.58+/-0.31 cm, P<0.05). In BAV, AA dilatation was independent of the severity of valve dysfunction. In TAV, aortic regurgitation but not stenosis correlated weakly with AA dilatation. Prevalence of AA dilatation >or= 4.5 cm in BAV with severe aortic stenosis and regurgitation was 38% and 41%, respectively.

CONCLUSION

Dilatation of the proximal aorta is a frequent finding in BAV and independent of the severity of valve dysfunction. With respect to the high prevalence of AA dilatation >or= 4.5 cm in BAV with severe valve dysfunction, careful assessment of the dimensions of the AA is crucial to identify patients in whom concomitant AA replacement is indicated according to current guidelines.

Surveillance of cardiovascular risk in the normotensive patient with repaired aortic coarctation

Background

Repaired coarctation of the aorta is associated with premature atherosclerosis and an increased risk of cardiovascular events even in normotensive subjects. To date clinical risk stratification has focused on brachial blood pressures ignoring the complex pulsatility of the aortic wave form. The aim of this study was to assess components of this pulsatility in a clinical setting and to suggest possible techniques to improve risk stratification.

Methods

This was a prospective study recruiting patients from a tertiary referral centre. Pulse wave morphology was assessed using applanation tonometry. B-mode ultrasound and cardiac magnetic resonance were used to assess carotid intimal–medial thickness and left ventricular mass.

Results

Forty-six subjects with repaired coarctation of the aorta (range 16–62 years; mean 31 years) and 20 matched controls were studied. Baseline brachial systolic and diastolic blood pressures were not statistically different between the 2 groups. Peripheral (62.5 mmHg (11.3) vs. 50.6 mmHg (15.0), p = 0.0008) and central (34.5 mmHg (7.7) vs. 28.7 mmHg (4.7), p = 0.005) pulse pressures were elevated in the coarctation patients compared to controls. The reflected pressure wave returned to the ascending aorta earlier in the coarctation group (p = 0.007) and the tension time index (TTI) was increased (p = 0.03). The sub-endocardial viability index (SVI) was reduced in the coarctation subjects (159 (33) vs. 186 (31)%; p = 0.009) but there was no differences in central augmentation index (p = 0.35).

Conclusions

This study demonstrates that there are patients with repaired coarctation who have an excellent mid-term outcome free from ventricular hypertrophy, carotid intima medial thickening and with relatively preserved vascular reactivity. However even in this “best outcome” cohort there were abnormal vascular characteristics that may predispose to increased cardiovascular risk. Simple non-invasive investigations can more extensively characterise these sub-clinical abnormalities and by utilised in long-term surveillance.

Ascending aortic dilation in patients with congenital complete heart block

BACKGROUND

The clinical spectrum and underlying pathophysiology of isolated congenital complete heart block (CCHB) remain incompletely understood. Aortic dilation has been anecdotally observed in some children with CCHB, but detailed reports are lacking.

OBJECTIVE

This study sought to systematically describe aortic size in children with CCHB and to investigate predictor variables associated with aortic dilation.

METHODS

A retrospective review of clinical features and echocardiograms was performed for all patients with CCHB and a structurally normal heart or simple anatomic lesions seen at our center over 22 years. Echocardiographic measurements were assigned z-scores using validated norms.

RESULTS

Sixty subjects met inclusion criteria. The median ascending aorta (AsAo) z-score was 2.2 (range -0.6 to 7.2) at first echocardiogram, with 30 of 58 (52%) having a z-score >2 (P <.0001) and 11 of 58 (19%) having a z-score >4. The distribution of aortic root dimensions was nearly normal with a median z-score of 0.4 (range -1.3 to 3.2). Although the AsAo remained dilated at the last echocardiogram (median z = 1.7, range -0.9 to 6.3), the trend toward normalization was significant (P = .002). Maternal autoantibody seropositivity and decreased left ventricular function were associated with AsAo dilation at initial echocardiogram in a multiple logistic regression model controlling for heart rate and indexed stroke volume (odds ratio 15, P = .03, and odds ratio 0.8, P = .02, respectively).

CONCLUSION

Potentially clinically significant AsAo dilation, but not aortic root dilation, is present in a large proportion of pediatric patients with isolated CCHB. Maternal autoantibody seropositivity and decreased left ventricular function at initial echocardiogram correlate with this previously unreported finding. This observation may indicate a previously unrecognized consequence of fetal exposure to these autoantibodies.

Exercise capacity and exercise hypertension after surgical repair of isolated aortic coarctation

There are contradictory reports whether exercise capacity is reduced in patients on long-term follow-up after coarctation repair. Data from unselected patient groups are missing. In a cross-sectional, long-term follow-up study of a tertiary congenital cardiology referral center, 260 patients (30.2+/-11.4 years old, 84 women), after surgical repair for isolated aortic coarctation (age at surgery 11.5+/-11.2 years), underwent a symptom-limited exercise test. Peak workload was 180+/-52 W, significantly less than the age- and height-related reference values (p<0.0005). A peak workload under 80% of expected was found in 200 patients (77%). Exercise performance of the patients was independent from age at surgery, type of surgery, or the systolic brachial-ankle blood pressure difference. The only exercise-limiting factor found was the chronic administration of diuretics to treat hypertension (p=0.005). Exercise hypertension, defined as a systolic blood pressure >2 SD above the load-dependent reference value, was found in 73 patients (28%). It was independently related to the systolic brachial-ankle blood pressure difference (p<0.0005) and diuretics administration (p=0.037). In conclusion, most patients after coarctation repair have a reduced exercise performance. This reduction is not related to the surgical results. Particularly, as these patients are at risk of early atherosclerosis, exercise should be promoted as primary prevention after restenosis, aortic or cerebral aneurysms, and severe exercise hypertension are ruled out.

Management of the ascending aorta in patients with bicuspid aortic valve disease

Bicuspid aortic valve (BAV) disease is the most common form of congenital heart disease, affecting 1-2% of the population. Only 20% of patients will maintain normal valve function throughout their life and more than 30% of patients will develop serious morbidity. It is a highly heritable condition, with transmission likely to be autosomal dominant. Patients with BAV have a 10-fold risk of aortic dissection when compared to the normal population. Management of BAV associated aortopathy represents a significant clinical challenge.

Occurrence of an ascending aorta aneurysm 25 years after cure of a tetralogy of Fallot

The patient, who had undergone a complete cure of a tetralogy of Fallot 25 years previously, was discovered to have an ascending aorta aneurysm on echography. Bentall's procedure was carried-out, using a modified indirect coronary artery transplantation based on the Cabrol technique. As reported in the literature complications are mainly right sided and less frequently occur on the left side in this disease. Including the hypothesis of the overload volume which may provoke aortic root dilation, there is also an intrinsic pathology of the media which could often be related to embryogenesis abnormalities, i.e., abnormal migration of cardiac neural crest cells which may explain this condition.

Histopathologic changes in ascending aorta and risk factors related to histopathologic conditions and aortic dilatation in patients with tetralogy of Fallot

OBJECTIVE

The purposes of this study were to evaluate the histologic characteristics of the aortic wall and the risk factors related to histopathology and aortic dilatation in patients undergoing intracardiac repair of tetralogy of Fallot.

METHODS

Operatively excised full-thickness aortic wall tissue from 98 consecutive patients undergoing intracardiac repair of tetralogy of Fallot aged 6 months to 47 years (mean 104.5 +/- 102.8 months; median 72 months) were studied by light microscopy. The receiver operating characteristic curve analysis was done to quantify the diagnostic accuracy of loss of lamellar counts and multiple logistic regression models.

RESULTS

Twenty-five (25.5%) aortic tissue specimens were indicated as histologically normal and were used as normal controls. The incidence of elastic fragmentation, increased ground substance, medionecrosis, smooth muscle disarray, and fibrosis was 74.5%, 54%, 39.8%, 26.5%, and 57.1%, respectively. A lamellar count of less than 60 was associated with a sensitivity of 80% and a specificity of 87.67%. Area under the receiver operating characteristic curve indicated that 93.37% (standard error +/- 0.039) of the time the value of lamellar count was lower for the abnormal histopathology group than for the normal group (P < .001). The risk of aortic dilatation was 15.97 times higher in patients with histopathologically abnormal aorta.

CONCLUSIONS

The majority of aortic media of the ascending aorta in cyanotic tetralogy of Fallot indicates significant loss of lamellar units and pre-existing intrinsic aortopathy. The changes are present since infancy and are more pronounced in older patients subjected to long-standing cyanosis and volume overload and may account for or may coexist with the higher incidence of aortic dilatation encountered in these patients.

Replacement of right coronary leaflet with bovine pericardium

Bovine pericardium was used to replace the right coronary leaflet to manage aortic insufficiency resulting from ventricular septal defect in 6 patients aged 15 to 34 years. Aortic insufficiency was severe in 5 patients and moderate in one. In all patients, the ventricular septal defect was repaired before aortic valvuloplasty. They were followed up for 5 to 6 months. No mortality was observed. Three patients had relief of aortic insufficiency, 2 had mild residual aortic insufficiency, and one had minor insufficiency not requiring re-operation. Replacement of the right coronary leaflet with bovine pericardium is a promising technique for young patients. The short-term outcomes are encouraging, but longer follow-up is required to assess the durability and function of bovine pericardium in the aortic position.

Idiopathic Pulmonary Trunk Aneurysm Causing Airway Obstruction in an Infant

We report a case of idiopathic pulmonary trunk aneurysm in an infant, in which the main clinical picture was airway obstruction. Aneurysmorraphy was the chosen surgical approach and showed to be successful on 13 months follow-up.

Management of pregnancy in women with palliated and unpalliated congenital heart defects

Medical advancements have made it possible for more women with congenital heart defects (CHDs) to carry successful pregnancies. Most CHD surgeries or interventions are palliative with persistent residua and sequelae exacerbated by the physiologic stresses of pregnancy. Preconception assessment, a tailored multidisciplinary approach during pregnancy, and a planned, elective delivery followed by careful postpartum monitoring may improve outcomes. Teratogenic medications should be stopped and changed to safer alternatives. Major hemodynamic changes in pregnancy, labor, and delivery may aggravate the underlying cardiovascular defects. Interventions or surgeries, when anticipated, should be performed before pregnancy. Antibiotic prophylaxis is indicated for nearly all palliated and unpalliated defects.

Coarctation Long-term Assessment (COALA): Significance of arterial hypertension in a cohort of 404 patients up to 27 years after surgical repair of isolated coarctation of the aorta, even in the absence of restenosis and prosthetic material

OBJECTIVE

Recent studies have demonstrated that there is a loss of aortic compliance in patients after coarctation repair. The clinical effect of this and other mechanisms apart from restenosis on the rate of arterial hypertension is unknown.

METHODS

From 1974 through 2000, 404 patients born before January 1, 1985, underwent surgical intervention for isolated aortic coarctation. From those 382 who are still alive, 273 patients aged 16 to 73 years (1-27 years after surgical intervention) underwent a structured clinical investigation according to a prospective protocol, including blood pressure measurement at all limbs, ambulatory blood pressure measurement, and symptom-limited exercise testing.

RESULTS

Sixty-seven (25%) patients were already taking antihypertensive drugs, and another 63 (23%) patients had an increased ambulatory blood pressure. Still another 26 (10%) patients had a blood pressure during exercise exceeding 2 standard deviations of reference values. Only 117 (43%) patients had a normal blood pressure reaction. From those 156 patients with hypertension, only 21 (13%) had a systolic brachial-ankle blood pressure difference of greater than 20 mm Hg, suggesting restenosis. In the patient group without restenosis (n = 245), independent risk factors for hypertension were repair with prosthetic material, male sex, a residual brachial-ankle blood pressure difference, and older age at follow-up.

CONCLUSIONS

The majority of patients were hypertensive at long-term follow-up after coarctation repair. This is caused by restenosis, defined by a gradient of greater than 20 mm Hg, in only a few patients. Even in those without prosthetic material or minimal-grade restenosis, there is a substantial incidence of arterial hypertension.

Abnormal aortic elastic properties in adults with congenital valvular aortic stenosis

BACKGROUND

Abnormalities of the aortic root are common in patients with a bicuspid aortic valve. Our aim was to investigate the elastic properties of the aortic root in patients with congenital aortic valvular stenosis (AS) in comparison with age- and gender-matched controls, and to investigate the influence of stenosis severity and aortic size on aortic root elasticity.

METHODS

Thirty-two adults (mean age 30.4+/-7.5 years, 22 men) with congenital AS without previous cardiovascular surgery were prospectively studied. Aortic root elasticity indices such as aortic stiffness index (ASI), aortic root distensibility (ARD), and aortic strain were calculated with the use of M-mode echocardiography.

RESULTS

ASI was significantly higher in patients compared to controls, 8.5+/-8.4 versus 4.0+/-1.4, respectively (P<0.01). Other indices of aortic root elasticity were similar between patients and controls: ARD was 4.2+/-3.6 versus 4.3+/-1.9 x 10(-6) cm(2)/dynes, respectively, and aortic strain was 12.4+/-9.6 versus 13.5+/-5.0%, respectively (P=NS for all). Correlations were found between aortic size and indices of aortic elasticity (i.e., aortic strain and ARD), denoting that an increased aortic dimension is associated with a stiffer aorta. Interestingly, no correlations were found between indices of severity of AS and aortic elasticity, suggesting that an abnormal aortic elasticity is independent of stenosis severity.

CONCLUSIONS

Congenital AS results in abnormal aortic elastic properties, independent of stenosis severity. Furthermore, there seems to be a relationship between aortic dimensions and aortic stiffness.

Clinical outcome and echocardiographic predictors of aortic valve replacement in patients with bicuspid aortic valve

BACKGROUND

Clinical outcomes and echocardiographic parameters associated with aortic valve replacement (AVR) for bicuspid aortic valve are scarce.

METHODS

We conducted retrospective analysis of 208 adults with bicuspid aortic valve referred for transthoracic echocardiograms.

RESULTS

The Kaplan-Meier survival free of death or need for cardiac surgery was 72% at 5 years. Cardiac surgery was performed in 19%, the majority (68%) for symptomatic aortic stenosis. Peak gradient 80 mm Hg or greater (hazard ratio 11.8, 95% confidence interval 3.7-37.8, P < .0001) and aortic valve area less than or equal to 0.75 cm(2) (hazard ratio 2.9, 95% confidence interval 1.0-8.5, P = .05) predicted the need for AVR. Patients with a large (54%) versus normal left ventricular outflow tract dimension underwent AVR for symptomatic aortic stenosis at a larger calculated aortic valve area (1.07 +/- 0.21 vs 0.75 +/- 0.18 cm(2), P < .0001) but at a similar peak gradient and velocity ratio (76 +/- 19 vs 76 +/- 22 mm Hg, P = not significant; 0.23 +/- 0.06 vs 0.26 +/- 0.12, P = not significant, respectively).

CONCLUSIONS

Clinical events are common among patients with bicuspid aortic valve. Peak gradient 80 mm Hg or more and aortic valve area less than or equal to 0.75 cm(2) predicts the need for AVR. Gradients and velocity ratio better reflect the hemodynamic burden of aortic stenosis in patients with a large left ventricular outflow tract.

Valve-Sparing Operation for Aortic Root Aneurysm Late After Mustard Procedure

The aortic valve reimplantation technique leads to excellent clinical outcome in patients with aortic valve incompetence and aneurysms of the ascending aorta. This technique is now applied for aneurysms of ascending aorta, aortic dissection type A, and even dilatation of pulmonary autograft after the Ross operation. We report a case of aortic root dilatation late after a Mustard operation for transposition of the great arteries that was successfully managed by valve-sparing aortic root reimplantation.

Aortic valve-sparing reimplantation for dilatation of the ascending aorta and aortic regurgitation late after repair of congenital heart disease

OBJECTIVE

Aortic regurgitation resulting from progressive dilatation of the aortic root late after surgical correction of congenital heart disease is now widely recognized. We reviewed our experience with aortic valve-sparing operations to access the effectiveness of this approach.

METHODS

Three patients, aged 28, 31, and 32 years, had progressive dilatation of the ascending aorta and aortic regurgitation 25, 27, and 28 years, respectively, after surgical repair of complex congenital heart disease. At the time of reoperation, the maximum diameter of the aortic root ranged between 50 and 55 mm.

RESULTS

All 3 patients survived the operation and were in New York Heart Association functional class II or less at a maximum of 9 years' follow-up. The most recent echocardiogram demonstrated mild or less aortic insufficiency with favorable systemic ventricular function.

CONCLUSIONS

Aortic valve-sparing reimplantation is an effective treatment for aortic root dilatation and aortic regurgitation after corrective repair of complex congenital heart disease. This procedure leads to correction of aortic regurgitation, favorable durability of the native aortic valve, and excellent hemodynamics, avoiding a prosthetic valve and anticoagulation.

Prosthetic replacement of the ascending aorta increases wall tension in the residual aorta

BACKGROUND

Prosthetic replacement of the ascending aorta with nonelastic vascular grafts impairs the local Windkessel function. Whether this increases wall tension in the remaining aorta is still a not completely investigated hypothesis but is of clinical relevance with respect to postprocedural development of aneurysms and dissections, especially in the proximal descending aorta.

METHODS

Fresh porcine thoracic aortas, including the root, were set up in a mock circulation before and after prosthetic replacement of the ascending aorta. Cyclic changes in aortic dimensions were measured by ultrasonic micrometers at defined positions at the proximal part of the descending aorta. At the same positions, aortic pressures were recorded simultaneously using Millar tip manometers. Wall thickness was measured after pulsatile testing, and the resulting wall tension was calculated from the Laplace law.

RESULTS

After prosthetic replacement of the ascending aorta, peak systolic pressure in the proximal descending aorta increased from 117.6 +/- 6.1 mm Hg to 129.2 +/- 6.3 mm Hg, resulting in a rise of wall tension by 12.4% +/- 4.2% (p = 0.001). The maximum rate of pressure rise (dp/dt(max)) increased by 42.6% +/- 16.4% (p < 0.001).

CONCLUSIONS

Replacement of the ascending aorta with noncompliant prosthetic material significantly increases wall tension and rate of pressure rise in the residual aorta. This may have clinical impact with respect to a sudden and sustained rise of mechanical load, especially at the vulnerable proximal descending aorta.

Risk Factors Associated With Reoperation and Mortality in 252 Patients After Aortic Valve Replacement for Congenitally Bicuspid Aortic Valve Disease

BACKGROUND

We aimed to determine the risk factors associated with mortality in patients with congenitally bicuspid aortic valve disease and dilation (<5 cm) of the ascending aorta after aortic valve replacement.

METHODS

We reviewed 252 patients with bicuspid aortic valve undergoing aortic valve replacement at our institution from 1971 through 2000. Patients undergoing concomitant replacement of the ascending aorta were excluded.

RESULTS

The average patient age was 61 +/- 15 years; 66.3% were male, and 40.5% of patients had coronary artery disease. The ascending aorta was normal (<4.0 cm) in 60.3%, mildly dilated (4.0 to 4.4 cm) in 24.2%, and moderately dilated (4.5 to 4.9 cm) in 15.5% of patients. Patients with moderate aortic dilatation had significantly lower prevalence of coronary artery disease compared with patients with normal ascending aortas (20.5% and 45.4%; p = 0.006). Mean follow-up was 8.9 +/- 6.3 years. Long-term survival was significantly different across the three groups (p = 0.004). The 5-, 10-, and 15-year estimates were 78%, 59%, and 37%, respectively, in the normal aorta group; 88%, 77%, and 46%, respectively, in the mild aortic dilation group; and 92%, 83%, and 70%, respectively, in the moderate aortic dilation group. No significant difference in cardiac death was found among the groups (p = 0.08). The significant predictors of survival using the Cox regression model were coronary artery disease, age, decade of surgery, and ejection fraction. Aortic dilation was not significant after adjusting for these other variables. At follow-up, 18 patients required reoperation, 17 for aortic valve prosthesis failure and 1 for ascending aorta aneurysm.

CONCLUSIONS

The present study highlights the important adverse effect of concomitant coronary artery disease, advanced age, earlier decade of surgery, and reduced left ventricular ejection fraction on survival after aortic valve replacement for bicuspid aortic valve in patients with no or mild and moderate (<5 cm) dilation of the ascending aorta.

Aortic root disease in tetralogy of Fallot

PURPOSE OF REVIEW

Progressive aortic root dilatation is a recognized feature of tetralogy of Fallot even in patients following initial reparative surgery. The underlying pathophysiology was initially attributed to altered hemodynamics resulting from longstanding volume overloading and stretching of the aortic root from increased right to left shunting. This review explores the pathophysiology and possible mechanisms for the aortic dilatation, and whether these changes are a reflection of the initial hemodynamic stress or a cellular expression of an unrecognized gene associated with conotruncal defects.

RECENT FINDINGS

The recent publication of two case reports of aortic aneurysm and dissection in tetralogy of Fallot patients re-emphasized the fact that aortic root dilatation can no longer be regarded as a benign problem in tetralogy of Fallot patients. Findings of intrinsic histological abnormalities in the aortic root and ascending aorta of tetralogy of Fallot patients suggest that intrinsic abnormalities may also play an important causative role.

SUMMARY

A better understanding of the pathophysiology will help to formulate future treatment and management strategies in the subgroup of tetralogy of Fallot patients with progressive aortic dilatation.

Approach to the patient with bicuspid aortic valve and ascending aorta aneurysm

Bicuspid aortic valve (BAV) disease is a common congenital heart valve abnormality accounting for a large number of valve replacements in the United States. Although still incompletely understood, the natural history of BAV disease is severe aortic stenosis and associated ascending aortic dilatation. In addition to the increased risk of endocarditis, aortic dissection and severe aortic valve dysfunction are responsible for most fatal complications. Thus, early and precise recognition of this condition is mandatory. The new American College of Cardiology/American Heart Association recommendations highlight the role of MRI and CT as complimentary tools to echocardiography for the diagnosis and surveillance of the morphology of the aortic valve and ascending aorta. Moreover, better understanding of the cellular mechanisms, including inflammation, bone formation, atherosclerotic-like processes, and aortic wall abnormalities, as well as the heritability and genetic predisposition for the disease, will define the potential for targeted medical therapies in the future. Currently, the treatment of this condition is primarily surgical. Although combined valve and ascending aorta replacement has been the most common surgical approach in the past, the increased cumulative risk of thrombotic and embolic events among these young patients has led to more conservative approaches. Several valve-sparing approaches with comparable mid-term results compared with the classic procedures have recently been reported. However, longer follow-up studies will be helpful to better define the advantages of these new surgical options. After a quick overview of the natural history of the BAV, this article provides an updated approximation of the current knowledge of the pathophysiology as well as the recommendations for the management and treatment of this disease.

Morphology and function of the bicuspid aortic valve with and without coarctation of the aorta in the young

This study sought to determine the morphology and function of bicuspid aortic valves (BAVs) with and without coarctation of the aorta (CoA) in a young population. The transthoracic echocardiograms of 117 patients with BAVs and 62 patients with CoA were retrospectively reviewed and compared with normal transthoracic echocardiographic results. In each patient, the area subtended by the aortic cusps and valve and the diameters of the aortic root at different levels were measured, and additionally in each BAV, the type of cusp fusion and the presence and degree of aortic stenosis and/or regurgitation were evaluated. The median age of patients with BAVs was 4 years (range 0 days to 34 years), and the median age of patients with CoA was 1.9 years (range 0 days to 16.5 years). BAVs with right and left coronary cusp fusion were significantly associated with CoA (p <0.0001) and cardiac anomalies (p <0.0001), whereas BAVs with noncoronary and right coronary cusp fusion were affected by valvar dysfunction (p <0.001). Compared with normal tricuspid aortic valves, BAVs had aortic root dilation, even in patients with no hemodynamic disturbance, particularly at the level of the ascending aorta (p <0.0001); the difference was still significant comparing BAVs and CoA with tricuspid aortic valves and CoA (p <0.0001). In conclusion, different morphologies of BAVs are associated with different cardiac abnormalities, valvar function, and aortic root dilation. Although detectable early in life, valvar dysfunction and aortic root dilation progress with age.

Elastic properties of the reconstructed aorta in hypoplastic left heart syndrome

BACKGROUND

Patients with repaired coarctation of the aorta retain abnormal elastic properties of the aorta. It is not known whether patients with hypoplastic left heart syndrome also manifest abnormal elastic properties after palliative surgery. The presence of such abnormalities may have important clinical implications as reduced aortic compliance might adversely impact single right ventricular function.

METHODS

We prospectively evaluated the elastic properties of the aorta in a cohort of patients with hypoplastic left heart syndrome who had undergone the Norwood procedure with aortic arch reconstruction and subsequent bidirectional Glenn or Fontan procedure. The hypoplastic left heart syndrome patients (n = 20) were compared with single-ventricle patients (n = 18) without history of arch reconstruction and patients with double-ventricular lesions (n = 22). Aortic elastic function was quantified by distensibility index and stiffness index. M-mode measurements of the transverse aortic arch were obtained with transesophageal echocardiography under general anesthesia. Patients were evaluated at a median age of 22.2 months with no age difference between patient subgroups.

RESULTS

Distensibility index was significantly less (p = 0.007) and stiffness index greater (p = 0.005) in the reconstructed arch of hypoplastic left heart syndrome patients compared with single-ventricle and double-ventricle patients.

CONCLUSIONS

Patients with hypoplastic left heart syndrome after Norwood palliation have increased aortic stiffness and decreased distensibility in the reconstructed transverse arch. As previous studies in adults have shown that decreased aortic compliance increases the energy cost of cardiac ejection, examination of modifications to the surgical technique that might improve elastic properties is warranted.

Marfan syndrome: what internists and pediatric or adult cardiologists need to know

Marfan syndrome (MFS) is one of the most frequent connective tissue disorders, showing striking pleiotropism and clinical variability. There is autosomal dominant inheritance with complete penetrance but variable expression. Approximately 25% of MFS patients have no family history of the syndrome and represent sporadic cases due to new mutations. This hazardous condition is often associated with premature cardiovascular death unless surveillance and management are optimized. The fibrillin gene (FBN1) encodes the structure of the connective tissue protein fibrillin. MFS is caused by mutations in the fibrillin gene, located on chromosome 15 at locus 15q21. Fibrillin abnormalities reduce the structural integrity of different body systems, primarily involving the heart valves, blood vessels, lungs, bones, tendons, ligaments, cartilages, eyes, skin, spinal dura and the CNS. Patients with MFS are likely to have too little fibrillin within these structures, resulting in clinically relevant problems. For example, in the aortic wall, deficient fibrillin may trigger progressive aortic ectasia and may result in aortic dissection.

Ascending aorta dilatation in aortic valve disease: morphological analysis of medial changes

We investigated whether and how the severity of medial degeneration lesions varies along the circumference of the dilated intrapericardial aorta. Two groups of aortic wall specimens, respectively harvested in the convexity and concavity of ascending aorta in 72 patients undergoing surgery for dilatation of the intrapericardial aorta associated with aortic valve disease, were separately sent for pathology, morphometry, and ultrastructural examination. Cystic medial necrosis, fibrosis, and elastic fiber fragmentation were classified into three degrees of severity; their mean degree and morphometric findings in the convexity and in the concavity specimens were compared by paired t-test. Correlation between echocardiographic degree of aortic dilatation and severity of medial degeneration was assessed separately for each of the two groups of specimens. Morphologically, medial degeneration was found in all cases; a higher mean degree was found in the convexity group (2.39 +/- 0.58 vs 1.44 +/- 0.65 in the concavity group; P < 0.001). At morphometry normal smooth muscle cells in the convexity specimens were significantly reduced (P = 0.007); the length (P = 0.012) and number (P = 0.009) of elastic fibers reduced and increased, respectively. Moreover, in the convexity specimens a significantly smaller amount of smooth muscle cells and an increase of immunohistochemical labeling of apoptosis-associated proteins in the subintimal layer of the media was noticed. Correlation between aortic ratio and medial degeneration degree was significant in the convexity group (P < 0.001), but not in the concavity group (P = 0.249). Scanning electron microscopy analysis confirmed morphological results and allowed us to better distinguish the early pathological cavities from the microvessels, which were in the outer media in normal aorta and ubiquitous in aortitis or atherosclerosis. Electron transmission microscopy analysis showed changes in the extracellular matrix and smooth muscle cells, and these changes increased from the intima to the adventitial layer of the media. In dilated intrapericardial aorta, medial degeneration changes and expression of apoptosis-associated proteins are more marked in the ascending aorta convexity, likely due to hemodynamic stress asymmetry. Ultrastructural findings allow us to distinguish the early medial changes not yet evident on light microscopy.

Progression rate of ascending aortic dilation in patients with normally functioning bicuspid and tricuspid aortic valves

Dilation of the ascending aorta (AA), which is disproportionate to associated valvular lesions, is a relatively well-recognized phenomenon in patients with a bicuspid aortic valve (BAV). The aim of this study was to evaluate the rate of changes in the AA dimensions and the outcome in patients with AA dilation and BAVs compared with patients with AA dilation and tricuspid aortic valves (TAVs). Serial transesophageal echocardiograms (>12 months apart) were performed in 113 consecutive patients (BAV, n=27 and TAV, n=86) with AA diameters of >or=40 and <or=60 mm, respectively, without associated significant aortic valve stenosis or regurgitation. Baseline diameters at the sinuses of Valsalva (SV), the sinotubular junction (STJ), and the tubular tract (TT) were similar in both groups (41.3+/-5.3 vs 42.3+/-6.3 mm, p=NS, 37.8+/-5.2 vs 38.7+/-5.5 mm, p=NS, and 47.3+/-5.3 vs 45.9+/-5.1, p=NS, respectively). During an average 3-year follow-up, the rate of AA diameter progression was similar for the BAV and TAV groups (0.86+/-0.81 vs 0.82+/-1.1 mm/year, p=NS for the SV; 1.06+/-1.6 vs 0.63+/-1.1 mm/year, p=NS for the STJ; and 0.81+/-1.1 vs 0.75+/-1.1 mm/year, p=NS for the TT, respectively). Three patients in the TAV group experienced cardiac death (2 died suddenly and 1 after emergency surgery for AA dissection); there was no occurrence of cardiac death in the BAV group. In conclusion, the rate of progression of AA aneurysms was similar in patients with BAVs and in those with TAVs. Furthermore, patients with BAVs did not have increased rates of AA related complications compared with patients with TAVs.

Ultrastructural pathology of aortic dissections in patients with Marfan syndrome:

Despite the discovery in 1990 that mutations in the fibrillin-1 gene cause the Marfan syndrome, the pathogenesis of the life-threatening dissections associated with this disease is far from elucidated. Both the massive number of known fibrillin-1 mutations that result in a heterogeneous patient population and the strongly heterogeneous histology of patients' aortae presumably contribute to this lack of knowledge. We performed a detailed ultrastructural immunoelectron microscopic and histochemical analysis of the dissected media of ascending aortae of 10 patients with Marfan syndrome and compared them with those of 6 patients without Marfan syndrome and 77 individuals without known aortic disease. Relatively similar abnormalities were found in both patient groups, although they were more numerous and more diffusely spread in the patients with Marfan syndrome than in the patients without Marfan syndrome. The most conspicuous ultrastructural defects were the formation of abrupt transverse tears in thick and compact elastic lamellae and the local breaking up of smooth muscle cell-elastic lamella connections (that largely consist of microfibrils and elastic extensions, protruding from the elastic lamellae). This breaking up was characterized by a strongly reduced number of microfibrils and a severe shortening of the elastic extensions. Finally, the elastic extensions detached from the lamellae to ultimately degenerate and disappear. These changes were found mainly in the oldest group of patients with Marfan syndrome, indicating that they represented a loss of previously normally developed structures. We also compared our findings with those from a recently developed murine Marfan model (Pereira L, Lee SY, Gayraud B, Andrilopoulos K, Shapiro SD, Bunton T, Biery NJ, Dietz HC, Sakai LY, Ramirez F. Pathogenetic sequence for aneurysm revealed in mice underexpressing fibrillin-1. Proc Natl Acad Sci. U. S. A. 1999: 96: 3819-3823). Next to similarities, several striking differences existed, demonstrating that this model is not fully representative of the human Marfan syndrome.

Central and peripheral arterial stiffness in patients after surgical repair of tetralogy of Fallot: implications for aortic root dilatation

OBJECTIVES

To test the hypotheses that (1) the central conduit arteries stiffen preferentially over the peripheral conduit arteries in patients with repaired tetralogy of Fallot (ToF); and (2) central arterial stiffening is related to aortic root dilatation.

DESIGN AND PATIENTS

Heart-femoral pulse wave velocity (PWV), femoral-ankle PWV, carotid augmentation index and body surface area-adjusted aortic sinotubular dimension were determined in 31 children after ToF repair and compared with those in 31 age-matched controls after left-to-right shunt repair. In addition, the PWVs and augmentation index were related to the sinotubular junction dimension.

SETTINGS

Tertiary paediatric cardiac centre.

RESULTS

Compared with controls, patients had significantly greater heart-femoral PWV (mean 666 (SD 151) v 587 (81) cm/s, p = 0.021) and carotid augmentation index (-14.1 (17.0)% v -25.2 (14.6)%, p = 0.016), whereas the right (888 (202) v 845 (207) cm/s, p = 0.42) and left (918 (227) v 851 (215) cm/s, p = 0.25) femoral-ankle PWVs were similar between the two groups. The sinotubular junction z score of patients was significantly greater than that of controls (4.7 (1.5) v 1.1 (1.4), p < 0.001). Univariate analysis showed that the sinotubular junction z score correlated positively with heart-femoral PWV (r = 0.43, p = 0.001) and carotid augmentation index (r = 0.46, p = 0.001). Multiple linear regression similarly identified heart-femoral PWV (beta = 0.30, p = 0.04) and carotid augmentation index (beta = 0.31, p = 0.04) (model R(2) = 0.26) as significant determinants of sinotubular junction z score.

CONCLUSIONS

The aorta stiffens in patients with repaired ToF, which may contribute to progressive dilatation of the aortic root in the long term.

Aortic dilatation in patients with bicuspid aortic valve

The association of a bicuspid aortic valve (BAV) with abnormalities of the proximal thoracic aorta, including dilatation, aneurysm and dissection, has been previously described, leading to the hypothesis of a common underlying developmental defect involving the aortic valve and the aortic wall. Consequently, any patient with BAV should receive a careful assessment not only of the valve function, but also of the aortic root and the ascending aorta. Dilatation of the proximal thoracic aorta is a common finding in patients with BAV and is believed to be related to aortic rupture and dissection. Because progressive dilatation can occur, careful long-term surveillance of the aortic dimensions is required. Prophylactic surgical repair of the dilated aorta should be recommended more aggressively for patients with BAV than for those with a tricuspid aortic valve. However, the optimal timing of aortic surgery in BAV patients remains uncertain because of the limited data available on the natural history of asymptomatic aortic dilatation.

Ascending aortic aneurysm following aortico-ventricular tunnel repair

Aortico-left ventricular tunnel is a very rare congenital anomaly. An 18-year-old boy had undergone tunnel closure at 3 years of age. A moderate degree of aortic regurgitation remained postoperatively. Seven years later, aortic valve replacement for aortic regurgitation was performed. Eight years later, the ascending aortic aneurysm had grown to 63 mm in diameter. This dilatation became an operative indication. Ascending aortic replacement was performed with a Dacron graft. Pathological examination of the resected aortic wall revealed cystic medial degeneration. We report a rare case of ascending aortic aneurysm following surgical repair of the aortico-left ventricular tunnel and aortic valve replacement.

Fate of bicuspid aortic valves in patients undergoing aortic root repair or replacement for aortic root enlargement

OBJECTIVE

To better understand the outcome of the bicuspid aortic valve (BAV) after valve-sparing root replacement, we evaluated BAV function after its preservation at the time of the ascending aorta (AA) repair.

PATIENTS AND METHODS

From January 1, 1994, through March 31, 2002, BAVs were preserved during repair of AA aneurysms in 21 patients (mean +/- SD age, 45+/-12 years; 13 males). We reviewed the clinical and surgical records of these patients for baseline characteristics, operative procedures, and data at latest follow-up.

RESULTS

The primary indication for operation was AA enlargement (median diameter, 55 mm; range, 43-65 mm) in 18 patients and severe aortic regurgitation (AR) in 3 patients. Preoperatively, the BAV exhibited mild or moderate stenosis in 5 patients (mean gradient, 25 mm Hg; range, 19-34 mm Hg), moderate AR in 2, and severe AR in 3. Aortic valve repair was performed in 11 patients. Seventeen patients had excision and graft replacement of the enlarged AA, and 4 patients had primary AA repair. There were no perioperative deaths. Moderate or severe AR was relieved in all patients early postoperatively and during follow-up (median, 2.5 years; maximum, 7.6 years). One patient required aortic valve replacement at 4.8 years for AR. An additional patient had recurrent, severe AR but was asymptomatic and has not undergone reoperation.

CONCLUSION

Repair of diseased BAVs or preservation of functionally normal BAVs during surgery for AA aneurysms has a low perioperative risk, and early results are encouraging. Additional observation is necessary to determine whether this strategy has real advantages over early aortic valve replacement.

Increased carotid and femoral intima-media thickness in patients after repair of aortic coarctation: influence of early repair

BACKGROUND

In patients, after repair of aortic coarctation, abnormal function of the proximal precoarctation arterial conduits has been demonstrated, but data on arterial wall structure of proximal and distal arteries in patients are scarce. The aim of our study is to compare intima-media thickness (IMT) of the carotid and femoral arteries in controls and patients after coarctation repair and to identify independent predictors of carotid and femoral IMT.

METHODS

A total of 137 patients after repair of aortic coarctation (89 male, median age 29.7 years, range 17-74 years, and median age at repair 6.3 years, range 0.01-46 years) and 46 age-matched controls underwent ambulatory blood pressure monitoring and B-mode ultrasound of the carotid and femoral arteries.

RESULTS

Twenty (15%) of the 137 patients were operated on before the age of 1 year ("early repair"). The patients with an early repair were younger compared to the controls and compared with the patients with a late repair (24.5 [10.5] vs 31.6 [8.4] years, P = .005, and vs 32.1 [10.5] years, P < .001, respectively). Eighty patients (59%) had hypertension on the basis of the results of the ambulatory blood pressure monitoring (mean daytime blood pressure > or = 135/85 mm Hg). The prevalence of hypertension was not significantly different between patients with an early or late repair. Although patients with an early repair were younger, both carotid and femoral IMT were increased in these patients compared to controls (common carotid artery 0.57 [0.11] vs 0.49 [0.07] mm, P < .001; common femoral artery 0.48 [0.10] vs 0.44 [0.05] mm, P = .033). In multivariable regression analyses, age at repair was only an independent predictor of femoral and not of carotid IMT.

CONCLUSIONS

Patients, after repair of aortic coarctation, have increased carotid and femoral IMT despite normal ambulatory blood pressures and successful previous repair. Early repair seems to preserve postcoarctation arterial wall structure, but seems to have only limited effect on precoarctation vessel walls, which supports the theory of a developmental defect of the proximal aorta and its branches.

Myocardial perfusion reserve in adults with cyanotic congenital heart disease

In patients with cyanotic congenital heart disease (CCHD), a right-to-left shunt results in systemic hypoxemia. Systemic hypoxemia incites a compensatory erythrocytosis, which increases whole blood viscosity. We considered that these changes might adversely influence myocardial perfusion in CCHD patients. Basal and hyperemic (intravenous dipyridamole) perfusion measurements were obtained with [13N]ammonia positron emission tomographic imaging in left (LV) and right (RV) ventricular and septal myocardium in 14 adults with CCHD [age: 34.1 yr (SD 6.5)]; hematocrit: 62.2% (SD 4.8)] and 10 healthy controls [age: 34.1 yr (SD 6.5)]. In patients, basal perfusion measurements were higher in LV [0.77 (SD 0.24) vs. 0.55 ml·min−1·g−1 (SD 0.09), P < 0.02], septum [0.71 (SD 0.16) vs. 0.49 ml·min−1·g−1 (SD 0.09), P < 0.001], and RV [0.77 (SD 0.30) vs. 0.38 ml·min−1·g−1 (SD 0.09), P < 0.001]. However, basal measurements normalized for the rate-pressure product were similar to those of controls. Calculated oxygen delivery relative to rate-pressure product was higher in the patients [2.2 (SD 0.8) vs. 1.6 (SD 0.4) × 10−5 ml O2·min−1·g tissue−1·(beats·mmHg)−1 in the LV, P < 0.05, and 2.0 (SD 0.7) vs. 1.4 (SD 0.3) × 10−5 ml O2·min−1·g tissue−1·(beats·mmHg)−1 in the septum, P < 0.01]. Hyperemic perfusion measurements in CCHD patients did not differ from controls [LV, 1.67 (SD 0.60) vs. 1.95 ml·min−1·g−1 (SD 0.46); septum, 1.44 (SD 0.56) vs. 1.98 ml·min−1·g−1 (SD 0.69); RV, 1.56 (SD 0.56) vs. 1.65 ml·min−1·g−1 (SD 0.64), P = not significant], and coronary vascular resistances were comparable [LV, 55 (SD 25) vs. 48 mmHg·ml−1·g·min (SD 16); septum, 67 (SD 35) vs. 50 mmHg·ml−1·g·min (SD 21); RV, 59 (SD 26) vs. 61 mmHg·ml−1·g·min (SD 27), P = not significant]. These findings suggest that adult CCHD patients have remodeling of the coronary circulation to compensate for the rheologic changes attending chronic hypoxemia.

Local delivery of osteopontin attenuates vascular remodeling by altering matrix metalloproteinase-2 in a rabbit model of aortic injury

OBJECTIVE

Vascular remodeling, often accelerated after cardiovascular procedures, may result in stenosis or aneurysm formation. The bone-associated protein osteopontin has been suggested to be involved in vascular remodeling, yet the effect of locally applied osteopontin in an acute vascular injury model of aortic calcification has not been examined.

METHODS

Vascular healing of rabbit thoracic aortas treated locally with recombinant osteopontin (dose: 1 microg; n = 16) or albumin (control, n = 16) after acute injury created by end-to-end anastomosis was evaluated. Matrix metalloproteinase-2 level was quantified by gelatin zymography. Proliferation of smooth muscle cells was detected by immunostaining for proliferative cell nuclear antigen.

RESULTS

Osteopontin-treated aortas showed significantly diminished vascular remodeling with less calcification (P = .001) and reduced anastomotic luminal stenosis (4% vs 28%, P = .002) compared with controls 2 months postsurgery. Moreover, osteopontin-treated aortas revealed a thickened adventitia with increased fibrosis (P = .006). Matrix metalloproteinase-2 level was up-regulated 2-fold with osteopontin treatment compared with control at 1 week, returning to baseline by 1 month. Staining for proliferation cell nuclear antigen disclosed an increase in proliferation cell nuclear antigen-positive smooth muscle cells in the media of osteopontin-treated aortas at 1 week, normalizing by 1 month.

CONCLUSIONS

These data suggest a beneficial effect of locally applied osteopontin after acute injury possibly by altering matrix metalloproteinase-2 activity and smooth muscle cell proliferation. Brief application of osteopontin may effectively enhance vascular healing by reducing calcification and thus maintaining luminal integrity. The role of the osteopontin-related increase in adventitial fibrosis on vascular healing has to be explored.