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

The Effect of Ascending Aortic Repair on Left Ventricular Remodeling

Left ventricular (LV) hypertrophy is common in patients with thoracic aortic diseases and is associated with increased long-term mortality. Thoracic aortic aneurysms are reported to increase LV afterload because of kinetic energy loss within the aneurysm sac, which may improve after surgical repair. However, LV afterload may also increase because of the stiffness of prosthetics used for aortic repair. We sought to investigate the long-term effect of surgical aortic repair with prostheses on postsurgical LV mass. We reviewed patients who underwent ascending aortic replacement with a prosthesis at our institution from January 2008 to December 2018. We calculated the LV mass index based on pre- and postoperative echocardiogram measurements. The primary outcome was the change in LV mass index 6 months after aortic repair. Patients aged <18 years and those who had concomitant cardiac operations, severe aortic valve disease, or who had no echocardiographic data were excluded. Of 1,008 patients who underwent ascending aortic replacement, 134 (51 with acute aortic dissections) were included. The median baseline and follow-up LV mass index were 107 (90 to 135) g/m² and 101 (83 to 123) g/m², respectively. Overall, there was a significant reduction of LV mass index over time (p = 0.03). LV mass index decreased in 77 patients (59%). Presentation due to acute aortic dissection (p = 0.03) and baseline LV mass index (p <0.001) were significant predictors of LV mass reduction. In conclusion, LV mass index may significantly decrease over time after the aortic repair, but the course is highly variable. The largest decrease occurred in patients who presented because of aortic dissections rather than for elective repair of aneurysms.

Impact of ascending aortic prosthetic grafts on early postoperative descending aortic biomechanics on cardiac magnetic resonance imaging

OBJECTIVES

Among patients with ascending thoracic aortic aneurysms, prosthetic graft replacement yields major benefits but risk for recurrent aortic events persists for which mechanism is poorly understood. This pilot study employed cardiac magnetic resonance to test the impact of proximal prosthetic grafts on downstream aortic flow and vascular biomechanics.

METHODS

Cardiac magnetic resonance imaging was prospectively performed in patients with thoracic aortic aneurysms undergoing surgical (Dacron) prosthetic graft implantation. Imaging included time resolved (4-dimensional) phase velocity encoded cardiac magnetic resonance for flow quantification and cine-cardiac magnetic resonance for aortic wall distensibility/strain.

RESULTS

Twenty-nine patients with thoracic aortic aneurysms undergoing proximal aortic graft replacement were studied; cardiac magnetic resonance was performed pre- [12 (4, 21) days] and postoperatively [6.4 (6.2, 7.2) months]. Postoperatively, flow velocity and wall shear stress increased in the arch and descending aorta (P < 0.05); increases were greatest in hereditary aneurysm patients. Global circumferential strain correlated with wall shear stress (r = 0.60-0.72, P < 0.001); strain increased postoperatively in the native descending and thoraco-abdominal aorta (P < 0.001). Graft-induced changes in biomechanical properties of the distal native ascending aorta were associated with post-surgical changes in descending aortic wall shear stress, as evidenced by correlations (r = -0.39-0.52; P ≤ 0.05) between graft-induced reduction of ascending aortic distensibility and increased distal native aortic wall shear stress following grafting.

CONCLUSIONS

Prosthetic graft replacement of the ascending aorta increases downstream aortic wall shear stress and strain. Postoperative increments in descending aortic wall shear stress correlate with reduced ascending aortic distensibility, suggesting that grafts provide a nidus for high energy flow and adverse distal aortic remodelling.

Reinterventions and new aortic events after aortic surgery in Marfan syndrome

OBJECTIVES

Pre-emptive strategies to manage the aortic complications of Marfan syndrome have resulted in improved life expectancy yet, secondary to the variation of phenotypic expression, anticipating the risk and nature of future aortic events is challenging. We examine rates of new aortic events and reinterventions in a Marfan cohort following initial aortic presentation.

METHODS

Retrospective cohort study of Marfan patients with aortic pathology presenting to our institution 1998-2018. Patients were grouped according to index event: aortic dissection or root aneurysm. Patients with aortic dissection were classified according to Debakey criteria. Incidence of new aortic events and frequency of reintervention were analysed.

RESULTS

One hundred and twenty-six aortic procedures were performed in 74 Marfan patients with a median follow-up of 7 years. Forty-seven patients had an index event of root aneurysm and 27 had aortic dissection. Following operative intervention in the aneurysm group, 7 patients developed Debakey III dissections raising the overall number of patients who developed dissection within this cohort to 34. Reinterventions were more frequent in the dissection group with full replacement of the native aorta in 5 patients.

CONCLUSIONS

After operative intervention on the proximal aorta, a proportion will develop distal pathology. A greater focus on factors contributing to future events, such as mapping genotypes to clinical course, may lead the way for targeted operative techniques and surveillance.

Postoperative and mid-term hemodynamic changes after replacement of the ascending aorta

OBJECTIVES

To evaluate aortic distensibility and pulse waveform patterns associated with the ascending aortic aneurysm, and to analyze the postoperative and mid-term hemodynamic changes induced by prosthetic replacement of the ascending aorta.

METHODS

Central blood pressure waves were recorded at the carotid artery level by means of a validated transcutaneous arterial tonometer in 30 patients undergoing prosthetic replacement of ascending aortic aneurysm and in 30 control patients. Measurements were obtained the day before surgery and 5 to 7 days and 16 to 20 months after surgery.

RESULTS

The ascending aortic aneurysm was associated with a less steep slope of early systolic phase of the pressure curve (pulsus tardus) compared with a control group (0.54 ± 0.18 mm Hg/ms vs 0.69 ± 0.26 mm Hg/ms; P = .011). Replacing the ascending aorta with a noncompliant vascular prosthesis steepened the pulse pressure slope during the early systolic phase in the postoperative period (0.77 ± .29 mm Hg/ms), providing values comparable with those of the control group in the mid-term (0.67 ± .20 mm Hg/ms). No change in aortic stiffness was found either postoperatively or in the mid-term after ascending aorta surgical replacement (carotid-femoral pulse wave velocity: preoperative, 9.0 ± 2.6 m/s; postoperative, 9.0 ± 2.9 m/s; mid-term postoperative, 9.3 ± 2.8 m/s).

CONCLUSIONS

This study does not confirm the assumption that substitution of the viscoelastic ascending aorta with a rigid prosthesis can cause serious hemodynamic alterations downstream, because we did not observe a worsening of global aortic distensibility after insertion of a rigid prosthetic aorta. The ascending aortic aneurysm is associated with a pulsus tardus.

Prosthetic aortic graft replacement of the ascending thoracic aorta alters biomechanics of the native descending aorta as assessed by transthoracic echocardiography

Introduction

In patients with ascending aortic (AA) aneurysms, prosthetic graft replacement yields benefit but risk for complications in the descending aorta persists. Longitudinal impact of AA grafts on native descending aortic physiology is poorly understood.

Methods

Transthoracic echocardiograms (echo) in patients undergoing AA elective surgical grafting were analyzed: Descending aortic deformation indices included global circumferential strain (GCS), time to peak (TTP) strain, and fractional area change (FAC). Computed tomography (CT) was used to assess aortic wall thickness and calcification.

Results

46 patients undergoing AA grafting were studied; 65% had congenital or genetically-associated AA (30% bicuspid valve, 22% Marfan, 13% other): After grafting (6.4±7.5 months), native descending aortic distension increased, irrespective of whether assessed based on circumferential strain or area-based methods (both p<0.001). Increased distensibility paralleled altered kinetics, as evidenced by decreased time to peak strain (p = 0.01) and increased velocity (p = 0.002). Augmented distensibility and flow velocity occurred despite similar pre- and post-graft blood pressure and medications (all p = NS), and was independent of pre-surgical aortic regurgitation or change in left ventricular stroke volume (both p = NS). Magnitude of change in GCS and FAC was 5–10 fold greater among patients with congenital or genetically associated AA vs. degenerative AA (p<0.001), paralleling larger descending aortic size, greater wall thickness, and higher prevalence of calcific atherosclerotic plaque in the degenerative group (all p<0.05). In multivariate analysis, congenital/genetically associated AA etiology conferred a 4-fold increment in magnitude of augmented native descending aortic strain after proximal grafting (B = 4.19 [CI 1.6, 6.8]; p = 0.002) independent of age and descending aortic size.

Conclusions

Prosthetic graft replacement of the ascending aorta increases magnitude and rapidity of distal aortic distension. Graft effects are greatest with congenital or genetically associated AA, providing a potential mechanism for increased energy transmission to the native descending aorta and adverse post-surgical aortic remodeling.

An Isolated Aneurysm of the Abdominal Aorta in a Patient with Marfan Syndrome-A Case Report

We present a case of successfully treated abdominal aortic aneurysm in a 24-year-old patient with Marfan syndrome. After initial physical and ultrasound examination, the multislice computed tomography (MSCT) scan revealed infrarenal aortic aneurysm of 6 cm in diameter, 10 cm long, along with slightly dilated iliac arteries. However, dimensions of aortic root, aortic arch, and descending suprarenal aorta were within normal limits. Further on, because the patient presented with signs of impending rupture, an urgent surgical intervention was performed. The patient was discharged in good general medical condition 7 days after surgery. After 6 months of follow-up, the patient's condition was satisfying and no MSCT signs of further aortic dissection/aneurysm were identified. To the best of our knowledge, a case of successful management of a patient with Marfans syndrome and truly isolated infrarenal and symptomatic abdominal aortic aneurysm has not been described in the literature before.

Impact of connective tissue disease on the surgical outcomes of aortic dissection in patients with cystic medial necrosis

Background

A retrospective analysis was performed to determine the impact of genetically diagnosed connective tissue disease (CTD) on the early and late outcomes of surgical treatment for aortic dissection in patients having aortic pathology associated with cystic medial necrosis (CMN).

Methods

Between 2003 and 2013, a total of 43 patients (37 ± 12.8 years old, 23 men, 20 women) who had undergone surgery for aortic dissection associated with CMN in the aortic wall underwent genetic examinations. Subsequently, there were 30 patients with CTD (CTD group) and 13 without CTD (non-CTD group).

Results

There were no early or late deaths (the follow-up rate was 100% for 57.1 ± 43.0 months). The median age was significantly lower in the CTD group (p = 0.030). The rate of elastic fiber loss was significantly higher in the CTD group (p = 0.014). In the long-term follow-up, there were no significant differences in the incidences of re-dissection (p = 0.332). However, re-operations were required more frequently in the CTD group (p = 0.037).

Conclusions

In patients with CTD as well as CMN, the onset of aortic dissection tends to be earlier, which would result in higher rates of re-operation, compared with the non-CTD group. Closer and stricter follow-up with medication and adequate surgical treatments with appropriate timing are mandatory for such high-risk patients.

Re-interventions on the thoracic and thoracoabdominal aorta in patients with Marfan syndrome

The advent of multi-gene panel genetic testing and the discovery of new syndromic and non-syndromic forms of connective tissue disorders have established thoracic aortic aneurysms as a genetically mediated disease. Surgical results in patients with Marfan syndrome (MFS) provide an important benchmark for this patient population. Prophylactic aortic root surgery prevents acute dissection and has contributed to the improved survival of MFS patients. In the majority of patients, re-interventions are driven by a history of dissection. Patients undergoing elective root repair have a low risk for re-interventions on the root itself. Experienced centers have results after valve-sparing procedures at 10 years comparable with those seen after a modified Bentall procedure. In patients where only the ascending aorta was replaced during the initial surgery, re-intervention rates are high as the root continues to dilate. The fate of the aortic arch in MFS patients presenting with dissection is strongly correlated with the extent of the initial surgery. Not replacing the entire ascending aorta and proximal aortic arch results in a high rate of re-interventions. Nevertheless, the additional burden of replacing the entire aortic arch during emergent proximal repair is not very well defined and makes comparisons with patients undergoing elective arch replacement difficult. Interestingly, replacing the entire aortic arch during initial surgery for acute dissection does not protect from re-interventions on downstream aortic segments. MFS patients suffering from type B dissection have a high risk for re-interventions ultimately leading up to replacement of the entire thoracoabdominal aorta even if the dissection was deemed uncomplicated by conventional criteria. While current guidelines do not recommend the implantation of stent grafts in MFS patients, implantation of a frozen-elephant-trunk to create a stable proximal landing zone for future endovascular or open procedures has emerged as a means to address aortic arch and descending aortic pathologies.

Non-aneurysmal abdominal aortic rupture in a patient with Marfan syndrome

Aortic rupture in the presence of aneurysmal disease is well understood and extensively described in the literature. However, aortic rupture in a non-aneurysmal aorta is far less common. In the few reported cases, perforations are believed to result from a penetrating atheromatous ulcer of the aorta. We describe a rare case of non-aneurysmal aortic rupture in a 68-year-old man with Marfan syndrome and a history of proximal aortic surgery. The urgent need for hemorrhage control precluded any consideration of an endovascular repair.

Effect of personalized external aortic root support on aortic root motion and distension in Marfan syndrome patients

OBJECTIVE

Personalized external aortic root support (PEARS) is a novel surgical approach with the aim of stabilizing the aortic root size and decreasing risk of dissection in Marfan syndrome patients. A bespoke polymer mesh tailored to each patient's individual aorta shape is produced by modeling and then surgically implanted. The aim of this study is to assess the mechanical effects of PEARS on the aortic root systolic downward motion (an important determinant of aortic wall stress), aortic root distension and on the left ventricle (LV).

METHODS/RESULTS

A cohort of 27 Marfan patients had a prophylactic PEARS surgery between 2004 and 2012 with 24 having preoperative and follow-up cardiovascular magnetic resonance imaging studies. Systolic downward aortic root motion, aortic root distension, LV volumes/mass and mitral annular systolic excursion before the operation and in the latest follow-up were measured randomly and blinded. After a median follow-up of 50.5 (IQR 25.5-72) months following implantation of PEARS, systolic downward motion of aortic root was significantly decreased (12.6±3.6mm pre-operation vs 7.9±2.9mm latest follow-up, p<0.00001). There was a tendency for a decrease in systolic aortic root distension but this was not significant (median 4.5% vs 2%, p=0.35). There was no significant change in LV volumes, ejection fraction, mass and mitral annular systolic excursion in follow-up.

CONCLUSIONS

PEARS surgery decreases systolic downward aortic root motion which is an important determinant of longitudinal aortic wall stress. Aortic wall distension and Windkessel function are not significantly impaired in the follow-up after implantation of the mesh which is also supported by the lack of deterioration of LV volumes or mass.

Total aortic arch replacement: superior ventriculo-arterial coupling with decellularized allografts compared with conventional prostheses

Background

To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts.

Methods

After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group). Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure-conductance catheter. From the hemodynamic variables end-systolic elastance (Ees), arterial elastance (Ea) and ventriculoarterial coupling were calculated. Characteristic impedance (Z) was assessed by Fourier analysis.

Results

While Ees did not differ between the groups and over time (4.1±1.19 vs. 4.58±1.39 mmHg/mL and 3.21±0.97 vs. 3.96±1.16 mmHg/mL), Ea showed a higher increase in the prosthesis group (4.01±0.67 vs. 6.18±0.20 mmHg/mL, P<0.05) in comparison to decellularized allografts (5.03±0.35 vs. 5.99±1.09 mmHg/mL). This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5±50.9 vs. 3.9±23.4%). Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6±8.3dyn·sec·cm⁻⁵ vs. 32.4±2.0dyn·sec·cm⁻⁵, P<0.05).

Conclusions

Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving ventriculoarterial mechanoenergetics after aortic arch replacement.

Natural history of Type B aortic dissection: ten tips

We present ten important specific tips regarding the natural history of Type B aortic dissection, which have a bearing on diagnosis and management decisions.

Toward individualized management of the ascending aorta in bicuspid aortic valve surgery: the role of valve phenotype in 1362 patients

OBJECTIVE

Decision making regarding the management of the ascending aorta (AA) in patients with a bicuspid aortic valve (BAV) undergoing valve surgery has hardly been individualized and remains controversial. We analyzed our individualized, multifactorial approach, focusing on the BAV phenotype.

METHODS

In 1362 patients (1044 men) undergoing aortic valve surgery, the BAV phenotypes were intraoperatively classified and retrospectively analyzed. The mean follow-up was 5.4±3.6 years (range, 0-14; 7334 patient-years), and the data were 96.5% complete. The individualized AA management decision process mainly included the AA diameter, age, body surface area, macroscopic AA configuration, and the perceived tissue strength of the aortic wall resulting in 3 AA treatment groups: no intervention, aortoplasty (AoP), and AA replacement (AAR).

RESULTS

In 906 patients (66.5%), no intervention was performed and 172 (12.6%) and 284 (20.9%) underwent AoP and AAR, respectively. The hospital mortality was 1.1% for no intervention, 0.6% for AoP, and 0.4% for AAR (P=.4). The 10-year survival was similar for all 3 groups and comparable to that of the general population. Five reoperations on the AA occurred, 4 in the no intervention and 1 in the AoP group. BAV type 2/unicuspid patients were younger and more had undergone AAR in absolute numbers and after allowing for the AA diameter. Also, in patients with BAV type 1 LR and regurgitation, AAR was performed more often.

CONCLUSIONS

The individualized, multifactorial management of AA in patients with BAV during aortic valve surgery leads to excellent results. The threshold AA diameter for intervention (AoP or AAR) varied from 34 to 51 mm (mean, 43.9). BAV type 2/unicuspid and BAV type 1 LR with regurgitation emerged as determinants for more liberal AAR in our practice. Longer term follow-up is necessary to confirm our conclusions.

Acute Aortic Dissection Determines the Fate of Initially Untreated Aortic Segments in Marfan Syndrome

Background—

The aim of the current study was to investigate incidence and causes of surgical interventions in primarily nontreated aortic segments after previous aortic repair in patients with Marfan syndrome.

Methods and Results—

Retrospective analysis of 86 consecutive Marfan syndrome patients fulfilling Ghent criteria that underwent 136 aortic surgeries and were followed at this institution in the past 15 years. Mean follow-up was 8.8±6.8 y. Thirty-day, 6-month, 1-year, and overall mortality was 3.5%, 5.8%, 7.0%, and 12.8%, respectively. Ninety-two percent of patients initially presented with aortic root, ascending aortic or arch lesions, whereas 8% presented with descending aortic or thoraco-abdominal lesions. Primary presentation was acute aortic dissection (AAD) in 36% (77% type A, 23% type B) and aneurismal disease in 64%. Secondary complete arch replacement had to be performed in only 6% of patients without AAD, but in 36% with AAD ( P =0.0005). In patients without AAD, 11% required surgery on primarily nontreated aortic segments (5 of 6 patients experienced type B dissection during follow-up), whereas in patients after AAD, 48% underwent surgery of initially nontreated aortic segments (42% of patients with type A and 86% of those with type B dissection; P =0.0002).

Conclusions—

The need for surgery in primarily nontreated aortic segments is precipitated by an initial presentation with AAD. Early elective surgery is associated with low mortality and reintervention rates. Type B dissection in patients with Marfan syndrome is associated with a high need for extensive aortic repair, even if the dissection is being considered uncomplicated by conventional criteria.

Current indications for surgical repair in patients with bicuspid aortic valve and ascending aortic ectasia

Preventive surgical repair of the moderately dilated ascending aorta/aortic root in patients with bicuspid aortic valve (BAV) is controversial. Most international reference centers are currently proposing a proactive approach for BAV patients with a maximum ascending aortic/root diameter of 45 mm since the risk of dissection/rupture raises significantly with an aneurysm diameter >50 mm. Current guidelines of the European Society of Cardiology (ESC) and the joint guidelines of the American College of Cardiology (ACC)/American Heart Association (AHA) recommend elective repair in symptomatic patients with dysfunctional BAV (aortic diameter ≥45 mm). In asymptomatic patients with a well-functioning BAV, elective repair is recommended for diameters ≥50 mm, or if the aneurysm is rapidly progressing (rate of 5 mm/year), or in case of a strong family history of dissection/rupture/sudden death, or with planned pregnancy. As diameter is likely not the most reliable predictor of rupture and dissection and the majority of BAV patients may never experience an aortic catastrophe at small diameters, an overly aggressive approach almost certainly will put some patients with BAV unnecessarily at risk of operative and early mortality. This paper discusses the indications for preventive, elective repair of the aortic root, and ascending aorta in patients with a BAV and a moderately dilated—or ectatic—ascending aorta.

Cardiovascular surgery in Marfan syndrome: implications of new molecular concepts in thoracic aortic disease

Acute dissection and rupture of aortic aneurysms comprise for 1–2% of all deaths in industrialized countries. Dilation of the aorta is caused by a multitude of mechanisms including inherited connective tissue disorders such as Marfan syndrome (MFS). MFS is one of the most common inherited connective tissue disorders affecting 1 in 5000 individuals. Although the phenotype of MFS can be quite variable, aneurysmal dilation of the aortic root and consecutive acute aortic dissection is the leading cause of death in this patient population. Over the past years it has been shown that a comprehensive understanding of this disorder provides greater understanding of vascular wall biology and identifies pathways relevant to aortic aneurysms and dissection in general. The current review discusses the surgical management of patients with MFS with a special emphasis on indications for surgery in this complex group of patients.

A diagnostic odyssey and successful repair of a progressive aneurysmal expansion after complex aortic surgery and stent grafting of the descending aorta

A 48-year-old patient with Marfan syndrome presented with an ascending aortic and arch periprosthesis hematoma (14.0 x 9.0 cm) and a descending aortic aneurysm (8.7 x 9.1 cm) developed over the last 2.5 years, after several operations on the ascending aorta and arch as well as stent-graft placement in the descending aorta. After a diagnostic odyssey, the small true aortic lumen was identified as the source for the ascending aortic periprosthesis hematoma and descending aortic aneurysm expansion. The present case report underlines several important issues in the combined surgical and interventional management of patients requiring multiple and complex procedures on the thoracic aorta.