Indications, Timing, and Prognosis of Operative Repair of Aortic Dissections

Surgical strategies in the management of chronic dissection of the thoracoabdominal aorta

Most operations for dissection of the thoracoabdominal aorta take place in the chronic phase of the disease, because the acutely dissected distal aorta is almost always initially treated non-surgically with aggressive pharmacological anti-impulse therapy. Identifying patients who are no longer responding to medical treatment is the first step in preventing further disease progression and rupture. Symptomatic aneurysms should be promptly repaired. Asymptomatic patients are followed until significant aortic dilation occurs and reaches a threshold of intervention: current guidelines endorse repair once a diameter of 5.5 cm is reached. In patients with heritable thoracic aortic disease (such as Marfan Syndrome), the threshold of intervention is often lowered. Aortic replacement typically centers on the dilatated segment. For all extents of repair, we use passive mild hypothermia, sequential aortic cross-clamping, aggressive reimplantation of intercostal and lumbar arteries, and cold renal perfusion whenever possible. For Crawford extents I and II thoracoabdominal aneurysm repair, we routinely use cerebrospinal fluid drainage, left heart bypass, and selective visceral perfusion. A four-branched graft approach to thoracoabdominal aortic aneurysm repair is frequently used in patients with chronic aortic dissection; this approach facilitates visceral artery perfusion during repair, expedites the distal anastomosis, and prevents subsequent visceral patch aneurysms. Lifelong imaging surveillance is necessary, because the distal aorta often continues to expand; residual aortic dissection commonly remains after repair and may necessitate further repair.

Non-A non-B aortic dissection: A literature review

Non-A non-B aortic dissections are an infrequent occurrence and represent a small proportion of aortic dissections. Treating this life-threatening medical emergency often requires surgeons to undertake some one of the most challenging surgical or endovascular cases in medicine. This literature review aims to define and classify non-A non-B dissections, describe their epidemiology as well as their pathology. This review also aims to discuss the range of surgical techniques employed in their treatment and management and to investigate the patient outcomes associated with each technique.

Acute type A aortic dissection in-hours versus out-of-hours: A systematic review and meta-analysis

OBJECTIVE

We sought to compare clinical outcomes in patients with acute type A aortic dissection that undergone surgical repair during in-hours (IH) versus out-of-hours (OOH).

METHODS

An electronic literature search was done till March 2020 to include studies with comparative cohorts of IH versus OOH. Primary outcomes were 30-day mortality, stroke, and reoperation for bleeding; secondary outcomes were acute kidney injury, total hospital stay, and intensive care unit stay.

RESULTS

Six articles with a total of 3744 patients met the inclusion criteria. Mean age was similar, 60 ± 12 versus 60 ± 13 in IH versus OOH (p = .25). Aortic root and total arch replacement were similar in both cohorts, 22% in IH versus 25% in OOH (risk ratio [RR], 1.10; 95% confidence interval [CI: 0.78, 1.55]; p = .58) and 29% in IH versus 32% in OOH (RR, 0.96; 95% CI [0.89, 1.04], p = .37) respectively. Reoperation for bleeding and stroke rate were similar, with 18% in IH versus 23% in OOH (RR, 0.89; 95% CI [0.73, 1.08]; p = .24), and 12% in IH versus 13% in OOH (RR, 0.83; 95% CI [0.66, 1.03]; p = .09) respectively. Thirty-day mortality was significantly lower in IH (RR, 0.81; 95% CI [0.72, 0.90]; p = .0001).

CONCLUSION

There was higher 30-day mortality rate during OOH surgery, yet this difference diminished following sensitivity analysis. There were no significant differences in major postoperative outcomes. Therefore, operating on such cases should be decided on clinical priority without delay.

Medical treatment of aortic aneurysms in Marfan syndrome and other heritable conditions

Thoracic aortic aneurysms can be triggered by genetic disorders such as Marfan syndrome (MFS) and related aortic diseases as well as by inflammatory disorders such as giant cell arteritis or atherosclerosis. In all these conditions, cardiovascular risk factors, such as systemic arterial hypertension, may contribute to faster rate of aneurysm progression. Optimal medical management to prevent progressive aortic dilatation and aortic dissection is unknown. β-blockers have been the mainstay of medical treatment for many years despite limited evidence of beneficial effects. Recently, losartan, an angiotensin II type I receptor antagonist (ARB), has shown promising results in a mouse model of MFS and subsequently in humans with MFS and hence is increasingly used. Several ongoing trials comparing losartan to β-blockers and/or placebo will better define the role of ARBs in the near future. In addition, other medications, such as statins and tetracyclines have demonstrated potential benefit in experimental aortic aneurysm studies. Given the advances in our understanding of molecular mechanisms triggering aortic dilatation and dissection, individualized management tailored to the underlying genetic defect may be on the horizon of individualized medicine. We anticipate that ongoing research will address the question whether such genotype/pathogenesis-driven treatments can replace current phenotype/syndrome-driven strategies and whether other forms of aortopathies should be treated similarly. In this work, we review currently used and promising medical treatment options for patients with heritable aortic aneurysmal disorders.

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.

A Perspective on Natural History and Survival in Nonoperated Thoracic Aortic Aneurysm Patients

There are many questions that remain unanswered in the understanding of the natural history of thoracic aortic aneurysm (TAA). This review will critically appraise the current published evidence on the natural history of TAA in nonoperated patients and their present rates of survival.

Effectiveness of intensive medical therapy in type B aortic dissection: A single-center experience

OBJECTIVE

Although the mainstay of managing acute descending thoracic aortic dissection (ADTAD) remains medical, certain patients will require emergency surgery for complications of rupture or ischemia. This study evaluates factors that affect outcome and determines which patients previously treated surgically would have been eligible for endovascular repair.

METHODS

A single-institution retrospective study was conducted of patients who presented with clinical signs of ADTAD that was confirmed by magnetic resonance angiography (MRA) or computed tomography (CT). All patients were admitted to the intensive care unit (ICU) and medically managed to maintain systolic blood pressure<120 mm Hg and heart rate<70 beats/min. Two treatment groups were identified: group 1 received medical treatment only; group 2 received medical treatment plus emergency surgery. Patient demographic and clinical data were correlated with 30-day group mortality and morbidity and need for emergency surgery. The MRA and CT scan images of group 2 were retrospectively reviewed to determine if currently available endovascular treatment could have been done. The Fisher exact test was used to compare between the groups, and P<.05 was considered significant.

RESULTS

Between 1991 and 2005, 83 patients (55 men) were treated for ADTAD. The mean age was 67 years (range, 38 to 85). Sixty-eight patients (82%) had hypertension, three (3.6%) had Marfan syndrome, and 51 (62%) were smokers. Twenty-five (32%) of the patients were receiving beta-blocker therapy before the onset of their symptoms. Back pain was the most common initial symptom (72.2%). Emergency surgery was required in 19 patients (23%): 12 for rupture or impending rupture, four for mesenteric ischemia, and three for lower extremity ischemia. The need for emergency surgery was significantly higher in smokers (P=.03), in patients>70 years old (P=.035), and in patients who were not receiving beta-blocker therapy before the onset of symptoms (P=.023). The combined overall morbidity rate was 33%, and the mortality rate was 9.6%. Morbidity in group 2 was 64% and significantly higher than the 23% in group 1 (P=.00227). The mortality rate was also higher in group 2 at 31.5% compared with group 1 at 1.6% (P=.0004). Factors affecting the overall mortality included age>70 years (P=.057), previous abdominal aortic aneurysm repair (P=.018), tobacco use (P=.039), and the presence of leg pain at initial presentation (P=.013). As determined from the review of radiologic data, 11 of 13 patients with scans available for review in group 2 could have been treated with currently available endovascular grafts.

CONCLUSIONS

Intensive medical therapies are effective in preventing early mortality associated with ADTAD. Predictably, the need for emergency surgery carries a high morbidity and mortality rate. Most patients in this series requiring emergency surgery could have been candidates for endovascular therapy had it been available.

What Is the Optimal Management of Late-Presenting Survivors of Acute Type A Aortic Dissection?

BACKGROUND

Although type A aortic dissections represent a surgical emergency, some patients present late after the onset of symptoms. Optimal management of this cohort has not been defined.

METHODS

Data on 195 patients with type A dissections followed up at a single institution between 1985 and 2005 were collected prospectively. Of these, 93 patients (47.2%) presented 48 hours or later after the initial onset of pain (group A), and the remaining 102 patients underwent immediate operative repair (group B). Median follow-up was 41.8 months (range, 0 to 386 months).

RESULTS

Patients in group A were older (68.8 versus 59.3 years, p = 0.0005) and had a higher incidence of coronary artery disease (42.5% versus 14.6%, p < 0.0001), pulmonary disease (26.6% versus 8.4%, p = 0.0023), and congestive heart failure (14.1% versus 1.0%, p = 0.0004). Long-term survival was similar, although group B showed a trend toward improved 30-day mortality (16.5% versus 8.7%, p = 0.1035). Of the 92 patients in group A, 53 (57.6%) eventually underwent operative repair a median of 8.2 days after symptom onset. There was a trend toward improved long-term survival among patients undergoing repair (p = 0.1031).

CONCLUSIONS

Initial medical management with interval operative repair of selected patients referred greater than 2 days following an acute type A dissection is a viable option. Delayed repair after optimization of the clinical condition and detailed evaluation of concomitant diseases results in excellent long-term results.

Central cannulation is safe in acute aortic dissection repair

OBJECTIVE

The site of cannulation for the repair of ascending aortic dissection remains controversial. It is not clear whether cannulation of the dissected vessel is safe or even preferred. We hypothesized that cannulation of the dissected aorta could be done safely with acceptable complication and mortality rates in this high-risk population.

METHODS

The charts of repairs of acute ascending aortic dissections (n = 70) from 1996 to 2005 were reviewed. Cannulation was accomplished in 24 patients via the dissected aorta (central) and in 46 patients through cannulation of the femoral or axillary artery (peripheral). All were converted to sidearm cannulation of the graft for reperfusion. Groups were compared on the basis of comorbidities in addition to mortality, complications, hospital stays and final disposition.

RESULTS

The groups were comparable on the basis of age and preoperative comorbidities. Similarly, there were no differences in bypass time, crossclamp time, or hypothermic circulatory arrest time between groups. Hospital mortality and postoperative complications, including stroke, were similar between groups, but the peripheral group experienced more cardiac events (peripheral 15% vs central 0%; P < .05) and higher mortality than the central group (peripheral 19.5% vs central 4.2%; P < .05).

CONCLUSIONS

Direct cannulation of the dissected aorta was safe compared with peripheral cannulation in these patients. Inasmuch as these data demonstrate that cannulation of the dissected ascending aorta is safe, this technique can be used to tailor the cannulation approach to specific anatomic and patient characteristics that might optimize postoperative outcomes in this disease entity.