Xiaogang Sun

Aortic root replacement by ministernotomy: technique and potential benefit

BACKGROUND Although minimally invasive surgical procedures have aroused much interest in cardiac surgery, difficulty still exists with its application in most of the operations on great arteries. This report summarizes our initial experience of aortic root replacement by a superior ministernotomy in terms of operative indications, operative techniques, and potential benefits. METHODS Between July 1999 and September 1999, 8 patients who were diagnosed with Marfan syndrome with aortic valve regurgitation underwent aortic root replacements with composite grafts. Clinical characteristics, in-hospital outcomes, and postoperative stay of these patients were compared with data of patients who had undergone Bentall procedure by standard median sternotomy from January to September 1999. RESULTS There was no death in either group of patients. Demographics were similar between the two groups of patients. In the mini-incision group, the mediastinal drainage was significantly less than the standard incision group. The mean operating time was significantly longer than that in the standard incision group. The cardiopulmonary bypass time and aortic cross-clamping time were similar in both groups of patients. The mean intubation time, postoperative blood transfusion amount, duration of intensive care unit stay and postoperative hospital stay were less than that of the standard incision group; however, they all showed no statistical significant difference. CONCLUSIONS Aortic root replacement by a superior ministernotomy in cardiopulmonary bypass with cannulas through the femoral artery and femoral vein or right atrium is a safe, reliable procedure with excellent exposure. The procedure provides a potential benefit of less trauma, quick recovery, and reduction of mediastinal drainage and reduction of blood transfusion.

Angiotensin II Induces an Increase in Matrix Metalloproteinase 2 Expression in Aortic Smooth Muscle Cells of Ascending Thoracic Aortic Aneurysms Through JNK, ERK1/2, and p38 MAPK Activation.

Abstract: In this study, we hypothesized that angiotensin II (Ang II) induces matrix metalloproteinase 2 (MMP-2) upregulation in aneurysmal smooth muscle cells (ASMCs) derived from ascending thoracic aortic aneurysms (ATAAs). We compared MMP-2 protein levels in ascending aortic specimens using Western blot and plasma concentrations by enzyme-linked immunosorbent assay between ATAA (n = 40) and coronary heart disease patients (n = 40). Additionally, the protein level of angiotensinogen (AGT) in the ascending aorta and the plasma concentration of Ang II were detected by Western blot and radioimmunoassay, respectively, in ATAA and coronary heart disease patients. In ATAA patients, Ang II and MMP-2 plasma levels were significantly increased (P < 0.05). Additionally, AGT and MMP-2 protein levels in the aorta of ATAA patients were higher (P < 0.01). Enhanced AGT suggested that the amount of Ang II in aneurysmal aorta specimens may be also increased, which was confirmed by immunofluorescent staining for Ang II. Moreover, we investigated the effect of Ang II on MMP-2 upregulation by ASMCs and determined the Ang II receptors and intracellular signaling pathways that are involved. Our results showed that treatment with Ang II significantly increased the expression of MMP-2 through the Ang II type 1 receptor (AT1R) and activated the 3 major mitogen-activated protein kinases (MAPKs), JNK, ERK1/2, and p38 MAPK. In conclusion, these results indicate that Ang II can induce MMP-2 expression elevation through AT1R and MAPK pathways in ASMCs and suggest that there is therapeutic potential for angiotensin receptor blocker drugs and MAPK inhibitors in the prevention and treatment of ATAAs.

Genetic testing of the FBN1 gene in Chinese patients with Marfan/Marfan-like syndrome.

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder typically involving the ocular, skeletal and cardiovascular systems, and aortic aneurysms/dissection mainly contributes to its mortality. Here, we performed genetic testing of the FBN1 gene in 39 Chinese probands with Marfan/Marfan-like syndrome and their related family members by Sanger sequencing. In total, 29 pathogenic/likely pathogenic FBN1 mutations, including 17 novel ones, were identified. In addition, most MFS patients with aortic disease (62%) had a truncating or splicing mutation. These results expand the FBN1 mutation spectrum and enrich our knowledge of genotype-phenotype correlations. Genetic testing for MFS and its related aortic diseases is increasingly important for early intervention and treatment.

Early and mid-term results after hybrid total arch repair of DeBakey type I dissection without deep hypothermic circulatory arrest.

OBJECTIVES The purpose of this study was to assess the efficacy of the hybrid total arch procedure for the treatment of DeBakey type I dissection by analyzing mid-term results. METHODS From November 2009 to September 2014, 56 patients with DeBakey type I dissection underwent hybrid total arch repair without deep hypothermic circulatory arrest. During the follow-up, computed tomographic imaging was performed to evaluate the aortic diameter, true lumen diameter, false lumen diameter and false patency at the following three levels: pulmonary bifurcation, diaphragm and superior mesenteric artery. RESULTS The hospital mortality rate was 3.6% (2/56 patients). Three patients exhibited type Ia endoleak during the operation and 1 patient demonstrated type II endoleak 5 days after surgery. During the follow-up, false lumen complete thrombosis was observed at the level of the pulmonary bifurcation in 94% of patients (P < 0.001). At the level of the diaphragm and superior mesenteric artery, false lumen thrombosis was observed in 68% (P < 0.001) and 36% (P < 0.001) of patients, respectively. No patient had type I or III endoleak and no reoperation was related to residual dissected aorta. The actuarial 1-, 3- and 5-year survival rates were 96.4% [95% confidence interval (95% CI), 91.5-100], 92.3% (95% CI, 85-99.6) and 89.6% (95% CI, 80.8-98.4), respectively. CONCLUSIONS For patients with DeBakey type I dissection, the hybrid total arch procedure can be safely adopted with good mid-term results and with low morbidity and mortality. Longer-term follow-up is required to confirm the viability of this technique.

Acute Kidney Injury after Total Arch Replacement Combined With Frozen Elephant Trunk Implantation: Incidence, Risk Factors, and Outcome

OBJECTIVES Acute kidney injury (AKI) is common after thoracic aortic surgery and is a significant predictor of morbidity and mortality. Total arch replacement (TAR) combined with frozen elephant trunk (FET) implantation has been reported to produce satisfactory clinical outcomes, whereas several features of the surgical procedure may induce postoperative AKI. The authors aimed to clarify the incidence of and risk factors for postoperative AKI and the association of AKI with short-term outcomes. DESIGN This study was a retrospective analysis of a prospectively collected cohort. A multivariate logistic regression model was used to identify predictors of postoperative AKI. SETTING Single center. PARTICIPANTS Clinical data were analyzed for 553 consecutive patients who underwent TAR combined with FET implantation between 2013 and 2016. INTERVENTIONS None MEASUREMENTS AND MAIN RESULTS: Postoperative AKI was defined using the Kidney Disease Improving Global Outcomes criteria. Postoperative AKI occurred in 77.6% of the whole cohort. Patients in stage 3 AKI were associated with a higher incidence of major adverse events and in-hospital and 90-day mortality (p < 0.001, p < 0.05, p < 0.01, respectively). In the multivariate analysis, male sex (odds ratio [OR] 1.94; 95% confidence interval [95% CI] 1.22-3.18; p = 0.005); older age (per 10 years) (OR 1.37; 95% CI 1.14-1.67; p = 0.001); elevated body mass index (per 5 kg/m2) (OR 1.41; 95% CI 1.08-1.87; p = 0.01); and prolonged cardiopulmonary bypass duration (per 30 minutes) (OR 1.17; 95% CI 1.01-1.37; p = 0.03) were identified as independent predictors of postoperative AKI. CONCLUSION TAR combined with FET implantation carries a high-risk for postoperative AKI compared with other types of thoracic aortic surgeries. Cardiopulmonary bypass duration was identified as the only modifiable predictor of AKI, and patients may benefit from moderate hypothermic circulatory arrest instead of deep hypothermic circulatory arrest.

Identification of gross deletions in FBN1 gene by MLPA

BackgroundMarfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by mutations in the FBN1 gene. Approximately 90% of classic MFS patients have a FBN1 mutation that can be identified by single-gene sequencing or gene-panel sequencing targeting FBN1. However, a small proportion of MFS patients carry a large genomic deletion in FBN1, which cannot be detected by routine sequencing. Here, we performed an MLPA (multiplex ligation-dependent probe amplification) test to detect large deletions and/or duplications in FBN1 and TGFBR2 in 115 unrelated Chinese patients with suspected MFS or early-onset aneurysm/dissection.ResultsFive novel large deletions encompassing a single exon or multiple exons in the FBN1 gene were characterized in five unrelated patients, of which four were proven by Sanger sequencing, and the breakpoints were identified. Three of them met the revised Ghent criteria when genetic results were not available, and the other two patients were highly suspected and diagnosed with MFS until the FBN1 deletions were identified.ConclusionsOur finding expands the mutation spectrum of large FBN1 deletions and emphasizes the importance of screening for large FBN1 deletions in clinical genetic testing, especially for those with classic Marfan phenotype.

In-hospital major adverse outcomes of acute Type A aortic dissection

OBJECTIVES Acute Type A aortic dissection exhibits poor in-hospital outcomes after emergency surgery. Evaluation of risk predictors for in-hospital major adverse outcomes (MAO) is key to reducing the mortality rate and improving the quality of care. METHODS We enrolled 70 patients who presented with postoperative MAO and 195 patients who recovered well. Through univariate and multivariate analyses, clinical characteristics were compared between the patients in the 2 groups. RESULTS In-hospital mortality was 6.4% in this series. The patients in the MAO group were older and had a higher frequency of coronary artery involvement by dissection (60.0% vs 21.0%) (P < 0.05). Preoperatively, when compared to the group of patients without MAO, the patients in the MAO group were more likely to have a neurological deficit (18.6% vs 9.7%) and, to a certain extent, lower limb symptoms encompassing visceral and renal malperfusion (20.0% vs 8.2%) (P < 0.05). Compared to patients with MAO, patients without MAO experienced longer duration from initial onset of symptoms to surgery and had an ascending aorta with a larger diameter. In patients with MAO, the average durations of cardiopulmonary bypass (CPB), cardiac arrest and hypothermic circulatory arrest were much longer than those in patients with no MAO (all P < 0.001). Multivariate analysis showed that in-hospital adverse outcomes were associated with older age [odds ratio (OR) = 1.047 (1.008-1.087), P < 0.05], presentation of lower limb symptoms prior to surgery [OR = 2.905 (1.109-7.608), P < 0.05] and long CPB duration [OR = 1.011 (1.005-1.018), P < 0.01]. When patients with acute Type A aortic dissection experienced a duration from symptom onset to surgery [OR = 0.993 (0.987-0.999), P < 0.05] or had an ascending aorta with a large diameter [OR = 0.942 (0.892-0.995), P < 0.05], the number of postoperative adverse events decreased significantly. CONCLUSIONS At a centre that has a large caseload, where practitioners can become proficient through experience as well as training, good outcomes can be dependably produced in patients with acute Type A aortic dissection and without malperfusion syndromes. For patients presenting with these risk features, MAO need to be anticipated, and the incidence of a composite end point of major adverse events remains unsatisfactory.

Aortic Surgical Emergencies in Young Children With Loeys-Dietz Syndrome.

Loeys-Dietz syndrome presents early in life with rapidly progressive aortic aneurysmal disease. Aortic emergency in young children with Loeys-Dietz syndrome is an extremely rare occurrence. In this communication we report on 2 young children whose diagnoses were missed and consequently underwent urgent aortic repair due to aortic emergencies. For personalized management of aortic disease in Loeys-Dietz syndrome patients, when and how do we intervene?