Type A Aortic Dissection in Marfan Syndrome

Aortic treatment in connective tissue disease

Connective tissue disease (CTD) represents a group of genetic conditions characterized by disruptive matrix remodeling. When this process involves aortic and vascular wall, patients with CTD have a high risk of developing arterial aneurysms, dissections and ruptures. Open surgical repair is still the gold standard therapy for patients with CTD with reasonable morbidity and mortality risk. The surgical treatment of CTD often requires multiple operations. In the endovascular era, fenestrated and branched stent grafts may play a role in reducing the complications of multiple open operations. Although the long-term results of endovascular treatment in the setting of CTD are unknown, it is generally accepted that endovascular treatment is restricted to selected patients with high surgical risk. In an emergency setting, endovascular intervention can serve as a lifesaving bridge to elective open aortic repair. Aortic centers performing a large volume of complex open and endovascular aortic repairs have started to combine these two techniques in a staged fashion. The goal is to reduce the morbidity and mortality associated with extensive aortic repairs in CTD patients. For this reason, recommend endovascular therapy when a "graft-to-graft" approach is possible. In this scenario, the surgeon who performs the open repair must take into consideration future interventions. Surgical repair in any aortic segment should allow creation of proximal and distal landing zones over 4 cm to secure the sealing of a future stent graft. Connective tissue disease should be treated with a multidisciplinary approach, in high volume centers. Endovascular treatment represents a potential option in patients at high risk for open repair. Staged hybrid procedures have emerged as a way to reduce spinal cord ischemia and avoid multiple open surgeries. The aim of this article is to discuss the management of aortic diseases in CTD, focusing on to the role of standard open surgery and emerging endovascular treatment, and to give an overview of the few series published regarding this topic with a small number of patients.

Total arch replacement and frozen elephant trunk for type A aortic dissection after Bentall procedure in Marfan syndrome

Background

We seek to report the long-term outcomes of the total arch replacement and frozen elephant trunk (TAR + FET) technique for type A aortic dissection (TAAD) following prior Bentall procedure in patients with Marfan syndrome (MFS).

Methods

Between 2003 and 2015, we performed TAR + FET for 26 patients with MFS who developed TAAD following a prior Bentall procedure. Mean age at FET 36.9±9.7 years and 24 were males. TAAD was acute in 8 (30.8%, all new dissections from precious root aneurysm) and chronic in 18 (69.2%, 15 residual and 3 new). The interval from Bentall procedure to FET averaged 6.4±5.8 years, which was significantly longer in the acute group (10.3±6.3 vs. 4.6±4.9, P=0.021). The early and long-term outcomes were compared between two groups and risk factors identified for late adverse events.

Results

Operative mortality was 11.5% (3/26). Stroke, lower limb ischemia and reexploration for bleeding occurred in 1 patient each (3.8%). Follow-up was complete in 100% (23/23) at mean 5.1±2.3 years (range, 0.9-11.2 years). The maximal diameter (DMax) of distal aorta in the chronic group was significantly greater at the unstented descending aorta [DA, (56.4±15.5 vs. 35.6±12.2 mm, P=0.006)] compared to acute patients. The false lumen was obliterated in 95.7% across the FET and 56.5% in the unstented DA. Distal aortic dilation occurred in 13 patients (11 chronic, 68.8%). Of those 11 patients, 4 underwent an open thoracoabdominal aortic repair and 3 died of distal aortic rupture. Late death occurred in 7 patients at mean 3.9±2.5 years. At 6 years, the incidence was 18% for death, 11% for distal aortic reoperation, and 71% for reoperation-free survival. Survival did not differ between two groups (75.0% vs. 71.3%, P=0.851), while acute patients had significantly higher freedom from late rupture and reoperation at 6 years (100% vs. 61.9%, P=0.046). Hypertension was the sole risk factor for distal aortic dilatation [hazard ratio (HR) =7.271; 95% confidence interval (CI), 1.814-29.143; P=0.005]. Risk factors for late adverse events were hypertension (HR =6.712; 95% CI, 1.201-37.503; P=0.030) and age <35 years (HR =6.760; 95% CI, 1.154-39.587; P=0.034).

Conclusions

The TAR and FET technique was feasible and efficacious for TAAD following previous Bentall procedure in patients with MFS. Early and late survival did not differ with acute and chronic dissections, while freedom from late rupture and reoperation is significantly higher in patients with acute TAAD. Patients with hypertension and aged <35 years are at higher risk for late distal aortic dilation, reoperation and death.

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.

Aortic dissection in patients with Marfan syndrome based on the IRAD data

Between January 1996 and May 2017, the International Registry on Acute Aortic Dissections has collected information on a total of 6,424 consecutive patients with acute aortic dissection, including 258 individuals with a diagnosis of Marfan syndrome. Patients with Marfan syndrome presented at a significantly younger age compared to patients without Marfan syndrome (38.2±13.2 vs. 63.0±14.0 years; P<0.001) and in general had fewer comorbidities, although they more frequently had a known aortic aneurysm and history of prior cardiac surgery. We noted significantly larger diameters of the aortic annulus and root in the Marfan syndrome cohort, but no larger diameters more distally. The in-hospital mortality in type A dissection was not significantly different in patients with or without Marfan syndrome, despite the differences in age and comorbidities and the lower incidence of aortic rupture in the Marfan syndrome cohort. In contrast, the in-hospital mortality of Marfan syndrome patients with type B dissection appears to be lower than that of patients without Marfan syndrome. The Marfan syndrome cohort that was treated with open surgery for type B dissection seemed to do especially well, with a 0% mortality rate (n=27). Follow-up data for type A and B dissections combined show an estimated five-year survival rate of 80.1% and an estimated reintervention rate of 55.3% in patients with Marfan syndrome. Such a high rate of reinterventions highlights the need for careful surveillance and treatment for patients with Marfan syndrome surviving the acute phase of aortic dissection.

Limited root repair in acute type A aortic dissection is safe but results in increased risk of reoperation

OBJECTIVE

Management of the aortic root is a challenge for surgeons treating acute type A aortic dissection.

METHODS

We performed a retrospective review of the acute type A aortic dissection experience at Stanford Hospital between 2005 and 2015 and identified patients who underwent either limited root repair or aortic root replacement. Differences in baseline characteristics were balanced with inverse probability weighting to estimate the average treatment effect on the controls. Weighted logistic regression was used to evaluate in-hospital mortality. Weighted Cox proportional hazards regression was used to evaluate differences in the hazard for mid-term death. Reoperation was evaluated with death as a competing risk with the Fine-Gray subdistribution hazard.

RESULTS

After we excluded patients managed either nonoperatively or with definitive endovascular repair, there were 293 patients without connective tissue disease who underwent either limited root repair or aortic root replacement. There was no difference in weighted perioperative mortality, odds ratio 0.89 (95% confidence interval [CI], 0.44-1.76, P = .7), and there was no difference in weighted survival, hazard ratio 1.12 (95% CI, 0.54-2.31, P = .8). Risk of reoperation was greater in limited root repair (11.8%, 95% CI, 0.0%-23.8%) than for root replacement (0%), P < .001.

CONCLUSIONS

Limited root repair was associated with increased risk of late reoperation after repair of acute type A aortic dissection. Surgeons with adequate experience may consider aortic root replacement in well-selected patients. However, given good outcomes after limited root repair, surgeons should not feel compelled to perform this more-complex operation.

Recurrent Aortic Dissection

Background:

Improved medical care after initial aortic dissection (AD) has led to increased survivorship and a population of individuals at risk for further cardiovascular events, including recurrent AD. Reports describing recurrent ADs have been restricted to small numbers of patients from single institutions. We used the IRAD (International Registry of Acute Aortic Dissection) database to examine the clinical profiles and outcomes of patients with recurrent AD.

Methods:

We identified 204 patients enrolled in IRAD with recurrent AD. For the primary analysis, patient characteristics, interventions, and outcomes were analyzed and compared with 3624 patients with initial AD. Iterative logistic modeling was performed to investigate variables associated with recurrent AD. Cox regression analyses were used to determine variables associated with 5-year survival. A subset of recurrent AD patients was analyzed for anatomic and demographic details of initial and recurrent ADs.

Results:

Patients with recurrent AD were more likely to have Marfan syndrome (21.5% versus 3.1%; P <0.001) but not bicuspid aortic valve (3.6% versus 3.2%; P =0.77). Descending aortic dimensions were greater in patients with recurrent AD than in patients with initial AD independently of sentinel dissection type (type A: 4.3 cm [3.5–5.6 cm] versus 3.3 cm [2.9–3.7 cm], P <0.001; type B: 5.0 cm [3.9–6.0 cm] versus 4.0 cm [3.5–4.8 cm], P <0.001), and this observation was accentuated among patients with Marfan syndrome. In multivariate analysis, the diagnosis of Marfan syndrome independently predicted recurrent AD (hazard ratio, 8.6; 95% confidence interval, 5.8–12.8; P <0.001). Patients with recurrent AD who presented with proximal followed by distal AD were younger than patients who experienced distal followed by proximal dissection AD (42.1±16.1 versus 54.3±14.8 years; P =0.004).

Conclusions:

Among those suffering acute aortic dissection, 5% have a history of a prior aortic dissection. Recurrent AD is strongly associated with Marfan syndrome.

MMP-2 gene polymorphisms are associated with type A aortic dissection and aortic diameters in patients

Matrix metalloproteinases-2 (MMP-2) plays an important role in the pathogenesis of type A aortic dissection (AD). The aim of this study was to evaluate the association of 3 single nucleotide polymorphisms (SNPs) in the MMP-2 gene with type A AD risk and aortic diameters in patients. We performed a case-control study with 172 unrelated type A AD patients and 439 controls. Three SNPs rs11644561, rs11643630, and rs243865 were genotyped through the MassARRAY platform. Allelic associations of SNPs and SNP haplotypes with type A AD and aortic diameters in patients were evaluated. The frequency of the G allele of the rs11643630 polymorphism was significantly lower in type A AD patients than in control subjects (odds ratio 0.705, 95% confidence interval 0.545-0.912, P = 0.008). The association remained significant after adjusting for clinical covariates (P = 0.008). Carriers of the GG genotype of the rs11643630 polymorphism had significantly smaller aortic diameters than those with GT genotype or TT genotype (P = 0.02). Further haplotype analysis identified 1 protective haplotype (GC; P = 0.008) for development of type A AD. Again, a significant correlation was observed between haplotype GC and AD size (P = 0.020). Our results suggest that MMP-2 gene polymorphisms contribute to type A AD susceptibility. In addition, MMP-2 gene SNPs are associated with AD size, which could be used as a target for the development of new drug therapy.

Evolution of surgical therapy for Stanford acute type A aortic dissection

Acute type A aortic dissection (AcA-AoD) is a surgical emergency associated with very high morbidity and mortality. Unfortunately, the early outcome of emergency surgical repair has not improved substantially over the last 20 years. Many of the same debates occur repeatedly regarding operative extent and optimal conduct of the operation. The question remains: are patients suffering from too large an operation or too small? The pendulum favoring routine aortic valve resuspension, when feasible, has swung towards frequent aortic root replacement. This already aggressive approach is now being challenged with the even more extensive valve-sparing aortic root replacement (V-SARR) in selected patients. Distally, open replacement of most of the transverse arch is best in most patients. The need for late aortic re-intervention has not been shown to be affected by more extensive distal operative procedures, but the contemporary enthusiasm for a distal frozen elephant trunk (FET) only seems to build. It must be remembered that the first and foremost goal of the operation is to have an operative survivor; additional measures to reduce late morbidity are secondary aspirations. With increasing experience, true contraindications to emergency surgical operation have dwindled, but patients with advanced age, multiple comorbidities, and major neurological deficits do not fare well. The endovascular revolution, moreover, has spawned innovative options for modern practice, including ascending stent graft and adaptations of the old flap fenestration technique. Despite the increasingly complex operations and ever expanding therapies, this life-threatening disease remains a stubborn challenge for all cardiovascular surgeons. Development of specialized thoracic aortic teams and regionalization of care for patients with AcA-AoD offers the most promise to improve overall results.

Aortic events in a nationwide Marfan syndrome cohort

BACKGROUND

Marfan syndrome is associated with morbidity and mortality due to aortic dilatation and dissection. Preventive aortic root replacement has been the standard treatment in Marfan syndrome patients with aortic dilatation. In this study, we present aortic event data from a nationwide Marfan syndrome cohort.

METHOD

The nationwide cohort of Danish Marfan syndrome patients was established from the Danish National Patient Registry and the Cause of Death Register, where we retrieved information about aortic surgery and dissections. We associated aortic events with age, sex, and Marfan syndrome diagnosis prior or after the first aortic event.

RESULTS

From the total cohort of 412 patients, 150 (36.4 %) had an aortic event. Fifty percent were event free at age 49.6. Eighty patients (53.3 %) had prophylactic surgery and seventy patients (46.7 %) a dissection. The yearly event rate was 0.02 events/year/patient in the period 1994-2014. Male patients had a significant higher risk of an aortic event at a younger age with a hazard ratio of 1.75 (CI 1.26-2.42, p = 0.001) compared with women. Fifty-three patients (12.9 %) were diagnosed with MFS after their first aortic event which primarily was aortic dissection [n = 44 (83.0 %)].

CONCLUSION

More than a third of MFS patients experienced an aortic event and male patients had significantly more aortic events than females. More than half of the total number of dissections was in patients undiagnosed with MFS at the time of their event. This emphasizes that diagnosing MFS is lifesaving and improves mortality risk by reducing the risk of aorta dissection.

An update on hypertensive emergencies and urgencies

Severe acute arterial hypertension is usually defined as 'hypertensive crisis', although 'hypertensive emergencies' or 'hypertensive urgencies', as suggested by the Joint National Committee and the European Society of Hypertension, have completely different diagnostic and therapeutic approaches.The prevalence and demographics of hypertensive emergencies and urgencies have changed over the last four decades, but hypertensive emergencies and urgencies are still associated with significant morbidity and mortality.Different scientific societies have repeatedly produced up-to-date guidelines; however, the treatment of hypertensive emergencies and urgencies is still inappropriate, with potential clinical implications.This review focuses on hypertensive emergencies and urgencies management and treatment, as suggested by recent data.

Is Previous Cardiac Surgery a Risk Factor for Short and Mid-term Mortality Following Total Aortic Arch Replacement in Patients with Stanford Type A Aortic Dissection?

BACKGROUND

The aim of this study was to evaluate if the previous cardiac surgery (PCS) is the risk factor for short- and mid-term mortality following total aortic arch replacement in patients with Stanford type A aortic dissection.

METHODS

Between February 2009 and February 2012, a total of 384 patients who suffered Stanford type A aortic dissection involving aortic arch underwent total aortic arch replacement with frozen elephant trunk. Of these patients, 36 patients had PCS. Logistic regression was used to identify if the previous cardiac surgery was the risk factor for in-hospital mortality. Propensity score-matching (1:1 match) was used to yield patients from the primary surgery group who matched PCS group with respect to pre-operative clinical characteristics and post-operative complications. Survival analysis and differences between the two groups were performed by the Kaplan-Meier estimate and the log-rank test.

RESULTS

The overall in-hospital mortality was 8%. Logistic multiple regression identified that cardiopulmonary bypass time≥ 300minutes (OR=12.05, p<0.001) and surgical period from symptom onset shorter than one week (OR=2.43, p=0.04) were final risk factors for in-hospital mortality and PCS was not the final risk factor. Of 36 patients with PCS, three patients died in the hospital and 33 patients were discharged from the hospital. Of these 33 patients, 32 patients matched primary surgery group successfully. During the follow-up period, two patients died in PCS group, one patient died in primary surgery group. The mean follow-up time was 35.38±14.12 months. The five-year survival was 96% for the primary surgery group. Previous cardiac surgery group five-year survival was 73%. Five-year survival was not significantly different between the two groups (p=0.84 log-rank test).

CONCLUSIONS

PCS is not the risk factor for short- and mid-term mortality following total aortic arch replacement in patients with Stanford type A aortic dissection.

Marfan syndrome is associated with recurrent dissection of the dissected aorta

BACKGROUND

Recurrent dissection of a previously dissected aortic segment has been reported as a rare, late complication in single case reports. The infrequency of this event makes informed risk assessment in an individual patient challenging.

METHODS

To investigate this issue we examined the database of the Massachusetts General Hospital Thoracic Aortic Center between January 1, 2003 and December 31, 2012. A retrospective review was performed to identify patients with both (1) an acute aortic dissection after a prior aortic dissection and (2) evidence of a new dissection within a previously dissected aortic segment creating a triple lumen aorta. Data were reviewed to identify factors predisposing to dissection of a previously dissected aortic segment.

RESULTS

Over a 10-year period we identified 5 cases of aortic dissection within a previously dissected aortic segment presenting as a new acute aortic syndrome. On average, the recurrent dissection occurred 1 decade after the first aortic dissection (mean = 9.8 ± 1.9 years). Patients identified in this series were significantly younger at first dissection and more likely to carry the diagnosis of Marfan syndrome. Aortic aneurysm diameter was quantified before and after the new dissection event and demonstrated a marked increase in aneurysmal size (mean increase = 1.6 ± 0.3 cm).

CONCLUSIONS

We conclude that medial degeneration, as seen in the Marfan aorta, represents a predisposing factor for recurrent dissection of the dissected aorta. Our data indicate that double aortic dissections cause significant arterial destabilization and a low threshold for surgical intervention is appropriate.

Best surgical option for arch extension of type B aortic dissection: the open approach

Arch extension of aortic dissection (AD) is reported to occur in 4-25% of patients presenting with acute type B AD. The DeBakey and Stanford classifications do not specifically account for this subset, however, recent studies have demonstrated that the prognosis of patients with arch extension in acute type B AD is virtually identical to that of others with type B AD. In this sense, it seems reasonable to extend the general management principles that are applied to classic acute type B AD even to patients with arch extension. This may be because even in patients with arch extension, most complications occur at locations distal to the arch, and therefore treatment of these patients is similar to that of complicated type B AD, namely thoracic endovascular aortic repair (TEVAR). Conversely, 10% of patients with acute type B AD and arch extension develop complications that are directly related to the arch pathology. This clinical scenario generally necessitates surgical arch repair through a sternotomy approach. The frozen elephant trunk technique combined with arch repair is a very reasonable option to treat this unique clinical entity that involves relatively distal locations of the aortic diseases. Combined arch and descending aorta replacement through thoracotomy is an alternative option particularly when the anatomical features of the target lesions are not suitable for a sternotomy approach or TEVAR. Nonetheless, the reported mortality associated with this approach has been exceedingly high. Hybrid arch repair is another consideration in treating these patients to reduce the treatment-related mortality and morbidity, especially when the arch pathology is limited to the distal part. Nevertheless, the safety and efficacy of this procedure in cases with more extensive arch involvement needs to be assessed in further studies in comparison with other treatment modalities.