Surgery for thoracic aortic disease in Japan: evolving strategies toward the growing enemies

The fate of the downstream aorta after open aortic repair for acute DeBakey type I aortic dissection: total arch replacement with elephant trunk technique versus non-total arch replacement†

OBJECTIVES

The aim of this study was to evaluate the fate of the downstream aorta following open aortic repair for acute DeBakey type I aortic dissection comparing total arch replacement (TAR) with the elephant trunk (ET) technique versus non-total arch replacement (non-TAR).

METHODS

From October 1999 to December 2016, 267 patients underwent open repair for acute DeBakey type I aortic dissection. A tear-oriented strategy was mainly used to determine the extent of graft replacement. Hospital mortality was 10.0% (12/120 patients) in the TAR group and 17.0% (25/147 patients) in the non-TAR group (P = 0.070). Late outcomes were compared in 230 hospital survivors (TAR: n = 108 and non-TAR: n = 122). Mean follow-up was 6.5 ± 4.6 years. The aortic diameters were measured at 4 levels, across 6 time points using computed tomography.

RESULTS

Freedom from additional aortic surgery for distal dilation was significantly better in the TAR group than the non-TAR group (TAR: 97.5 ± 1.8% at 5 years and non-TAR: 88.2 ± 3.4% at 5 years, P = 0.045). Freedom from a distal aortic event was also significantly better in the TAR group compared with the non-TAR group (TAR: 97.2 ± 1.6% at 5 years and non-TAR: 80.7 ± 4.2% at 5 years, P = 0.013). In the non-TAR group, the aortic arch diameter significantly increased (P < 0.001). Significant aortic remodelling occurred at the proximal descending aorta in the TAR with ET group (P < 0.001).

CONCLUSIONS

The TAR with ET reduced the need for additional distal aortic repair compared to non-TAR. TAR with ET prevented unfavourable aortic growth in both the aortic arch and the proximal descending aorta.

The fate of aortic root and aortic regurgitation after supracoronary ascending aortic replacement for acute type A aortic dissection

BACKGROUND

The aim of this study was to evaluate the fate of the preserved aortic root after supracoronary aortic replacement for acute type A aortic dissection.

METHODS

Between October 1999 and March 2018, 339 patients underwent supracoronary aortic replacement for acute type A aortic dissection at our institution. Late outcomes were evaluated, including overall survival, aortic-related death, and aortic root-related reoperation. The median follow-up was 3.7 years (1.4-8.4 years).

RESULTS

Operative mortality was 46 patients (13.6%). The cumulative incidences at 5 years for aortic root-related reoperation, aortic-related death, and non-aortic related death were 2.5%, 14.5% and 12.4%, respectively. Multivariable Cox hazard regression analysis demonstrated greater sinus of Valsalva diameter and number of commissural detachments to be significant risk factors for a composite outcome consisting of aortic-related death or aortic root-related reoperation. Mixed-effects regression demonstrated that sinus of Valsalva diameter significantly increased with time (P < .001), and aortic regurgitation significantly worsened (P < .001).

CONCLUSIONS

Sinus of Valsalva diameter and commissural detachment were independent predictors of unfavorable outcomes after supracoronary aortic replacement. Close follow-up is particularly necessary for these patients, and aortic root replacement at the time of initial operation may lead to more favorable late outcomes.

Bicuspid Aortic Valve: An Update in Morphology, Genetics, Biomarker, Complications, Imaging Diagnosis and Treatment

The bicuspid aortic valve, a kind of heart disease that comes from parents, has been paid attention around the world. Although most bicuspid aortic valve (BAV) patients will suffer from some complications including aortic stenosis, aortic regurgitation, endocarditis, and heart dysfunction in the late stage of the disease, there is none symptom in the childhood, which restrains us to diagnose and treatment in the onset phase of BAV. Hemodynamic abnormalities induced by the malformations of the valves in BAV patients for a long time will cause BAV-associated aortopathy: including progress aortic dilation, aneurysm, dissection and rupture, cardiac cyst and even sudden death. At present, preventive surgical intervention is the only effective method used in this situation and the diameter of the aorta is the primary reference criterion for surgery. And the treatment effects are always not satisfactory for patients and clinicians. Therefore, we need more methods to evaluate the progression of BAV and the surgery value and the appropriate intervention time by combining basic research with clinical treatment. In this review, advances in morphology, genetic, biomarkers, diagnosis and treatments are summarized, which expects to provide an update about BAV. It is our supreme expectations to provide some evidences for BAV early screening and diagnosis, and in our opinion, personalized surgical strategy is the trend of future BAV treatment.

Anatomical variations of aortic arch vessels in Japanese patients with aortic arch disease

OBJECTIVES

The present study analyzed the prevalence of variations of the aortic arch branching in Japanese population, comparing patients with aortic arch disease with healthy controls.

METHODS

Between from October 1999 and December 2015, 815 Japanese patients with aortic arch disease defined as aortic arch aneurysm (diameter ≥ 45 mm) and aortic dissection (group A) underwent aortic arch surgery in our institution. As a control group, 1506 traumatic screened patients were enrolled (group C).

RESULTS

Aortic arch anomaly was diagnosed in 140 patients (17.2%) in the group A and in 222 patients (14.7%) in the group C (p = 0.125). Significant differences were found in the incidence of aberrant subclavian artery (A: 14 patients, 1.7%, vs. C: 8 patients, 0.5%, p = 0.006). Significantly more patients with aortic arch aneurysm in the group A had anomalies of the aortic arch compared with the group C (p = 0.009), including bovine aortic arch (p = 0.049) and aberrant subclavian artery (p < 0.001). In term of aneurysm location, bovine arch was detected in more patients with proximal arch aneurysm (15.7%, p = 0.043), whereas aberrant subclavian artery was in more patients with distal location (3.7%, p < 0.001). No difference was found in aortic arch anomaly in patients with acute or chronic dissection.

CONCLUSION

Aberrant subclavian artery was a significant maker of aortic arch disease in Japanese populations. Bovine arch was a risk maker of proximal arch aneurysm, and aberrant subclavian artery was a risk factor of distal arch aneurysm.

Optimized induction of beta common receptor enhances the neuroprotective function of erythropoietin in spinal cord ischemic injury

BACKGROUND

Paraplegia remains the most feared complication of complex thoracoabdominal aortic intervention. Although erythropoietin (EPO) has demonstrated neuroprotective effects in spinal cord ischemia, it does not work until expression of the beta common receptor subunit of the EPO receptor (βcR) is induced by ischemia. We hypothesized that the βcR can be induced by diazoxide (DZ), amplifying the neuroprotective effects of EPO in spinal cord ischemia-reperfusion injury.

METHODS

For the DZ time trial, adult male C57/BL6 mice received DZ (20 mg/kg) by oral gavage. Spinal cords were harvested after 0, 12, 24, 36, and 48 hours of administration. To evaluate optimal dosing, DZ was administered at 0, 5, 10, 20, and 40 mg/kg. The expression of βcR was assessed by Western blot analysis. Five groups were studied: PBS (pretreatment)+PBS (immediately before), PBS+EPO, DZ+PBS, DZ+EPO, and sham (without cross-clamping). Spinal cord ischemia was induced by 4 minutes of thoracic aortic cross-clamping. Functional scoring (Basso Mouse Score) was done at 12-hour intervals for 48 hours, and spinal cords were harvested for histological analysis.

RESULTS

Western blot analysis demonstrated that optimal βcR up-regulation occurred at 36 hours after DZ administration, and the optimal DZ dosage for βcR induction was 20 mg/kg. Motor function at 48 hours after treatment was significantly better preserved in the DZ+EPO group compared with all other groups, and was significantly better preserved in the DZ only and EPO only groups compared with control (PBS+PBS).

CONCLUSIONS

Pharmacologic up-regulation of βcR with DZ can increase the efficacy of EPO in preventing spinal cord ischemia and reperfusion injury. Improved understanding of this synergetic mechanism may serve to further prevent ischemic complications for high-risk aortic intervention.

Early and mid-term outcomes of endovascular and open surgical repair of non-dissected aortic arch aneurysm†

OBJECTIVES

With the introduction of endovascular stent graft technology, a variety of surgical options are available for patients with aortic aneurysms. We sought to evaluate early-term and mid-term outcomes of patients undergoing endovascular and open surgical repair for non-dissected aortic arch aneurysm.

METHODS

Overall, 200 patients underwent treatment for isolated non-dissected aortic arch aneurysm between January 2008 and February 2016: 133 patients had open surgery and 67, endovascular repair. Early-term and mid-term outcomes were compared.

RESULTS

Seventy percent ( n  = 47) needing endovascular repair underwent fenestrated stent graft and 30% ( n  = 20) underwent the debranched technique. Patients in the open surgery group were younger (71 vs 75 years, P  < 0.001) and had a lower prevalence of ischaemic heart disease (11% vs 35%, P  < 0.001). Intensive care unit stay (1 vs 3 days, P  < 0.001), hospital stay (11 vs 17 days, P  < 0.001) and surgical time (208 vs 390 min, P  < 0.001) were lower in the endovascular repair group than in the open surgery group. There were 3 in-hospital deaths each in the open surgery and endovascular groups (2% vs 5%, respectively, P  = 0.40). Mid-term survival ( P  < 0.001) and freedom from reintervention ( P  = 0.009) were better in the open surgery than in the endovascular repair group. No aneurysm-related deaths were observed. The propensity-matched comparison ( n  = 58) demonstrated that survival was better in the open surgery group ( P  = 0.011); no significant difference was seen in the reintervention rate ( P  = 0.28).

CONCLUSIONS

Close follow-up for re-intervention may reduce the risk for aneurysm-related deaths and provide acceptable outcomes in patients undergoing endovascular repair.

Clinical significance of chronic obstructive pulmonary disease in patients undergoing elective total arch replacement: analysis based on the Japan Adult Cardiovascular Surgery Database

Objectives

We investigated the impact of chronic obstructive pulmonary disease (COPD) on in-hospital outcomes of patients undergoing conventional total aortic arch replacement (TAR), based on the Japan Adult Cardiovascular Surgery Database.

Methods

A total of 12 590 patients who underwent elective TAR between 2008 and 2013 were retrospectively reviewed. Patients were divided into 4 categories: normal respiratory function (control), with ratio of forced expiratory volume of air in 1 s (FEV 1 ) to forced vital capacity (FVC) of 76% or greater (TAR, n  = 10 040); mild COPD, with FEV 1 /FVC ratio 60-75% and/or use of bronchodilator (TAR, n  = 1890); moderate COPD, FEV 1 /FVC ratio 50 to 59% and/or use of steroids (TAR, n  = 504); and severe COPD, FEV 1 /FVC ratio less than 50% and/or presence of respiratory failure (TAR, n  = 156).

Results

In-hospital mortality was 5.7% (5.2% in controls, 7.0% in mild COPD, 9.3% in moderate COPD and 9.0% in severe COPD). A significant trend towards the severity of COPD was noted ( P  < 0.0001). A higher incidence of postoperative pneumonia (6.0% in control, 11.0% in mild COPD, 12.3% in moderate COPD and 15.4% in severe COPD; P  < 0.0001) and a greater need for prolonged ventilation (17.5% in control, 22.0% in mild COPD, 26.6% in moderate COPD and 29.5% in severe COPD; P  < 0.0001) were observed in cases of more severe COPD. The odds ratio of moderate/severe COPD for in-hospital mortality was 1.44 with confidence interval of 1.08-1.91 ( P  = 0.012).

Conclusions

There was a significant increase in in-hospital mortality and morbidity with increasing severity of COPD in patients who underwent TAR.

Current surgical results of acute type A aortic dissection in Japan

Current surgical results of acute type A aortic dissection in Japan are presented. According to the annual survey by the Japanese Association of Thoracic Surgery, 4,444 patients with acute type A aortic dissection underwent surgical procedures and the overall hospital mortality was 9.1% in 2013. The prevalence of aortic root replacement with a valve sparing technique, total arch replacement (TAR), and frozen stent graft are presented and strategies for thrombosed dissection or organ malperfusion syndrome secondary to acute aortic dissection are discussed.

Blood flow analysis of the aortic arch using computational fluid dynamics

OBJECTIVES

To obtain predictive information regarding aortic disease, we evaluated how blood flow inside the aortic arch was influenced by thoracic aortic aneurysms. In addition, to reveal the optimal intraoperative management in these cases, we examined blood flow during right subclavian arterial (rSCA) perfusion using computational fluid dynamics (CFD).

METHODS

Patient-specific models of the aortic arch were made with six different patterns based on the computed tomographic images. CFD models with finite volume methods were created to simulate the physiological pulsatile flow including the peripheral reflection wave, characteristic impedance and autonomous regulation system. Flow stream patterns, wall shear stress (WSS) and the oscillatory shear index (OSI) were calculated during one cardiac cycle. Furthermore, flow streamlines during rSCA perfusion were simulated under different perfusion flows.

RESULTS

Aortic dilatation caused vortical disturbed flow in a dilated space, resulting in turbulent flow not only inside the aneurysm but also in the proximal and/or distal normal aortic portion. In patients with a dilated thoracic aorta, there was a helical spiral flow with a circumferential vortex in systole. In patients with an arch aneurysm, turbulent flow inside the aneurysm caused a high OSI at the tip of the aneurysm. A high OSI was detected at the orifice of the supra-aortic branches, sinotubular junction, posterior lateral side of the ascending aorta and lesser curvature of the proximal descending aorta. rSCA perfusion revealed that the right common carotid artery was perfused by blood flow from rSCA throughout the cardiac cycle. With 75% of the flow from the rSCA, blood flow from the heart reached the left common carotid and subclavian artery only during a short period during the peak of systole.

CONCLUSIONS

A dilated aorta causes a turbulent flow pattern in the aortic arch. The high OSI site was similar to the favourite entry site for acute aortic dissection, indicating the causal relationship between mechanical stress and acute aortic dissection. rSCA cannulation might be cerebroprotective from ascending aortic plaque.