Blood flow assessment technology in aortic surgery: a narrative review.

Background and Objective: Blood flow assessment is an emerging technique that allows for assessment of hemodynamics in the heart and blood vessels. Recent advances in cardiovascular imaging technologies have made it possible for this technique to be more accessible to clinicians and researchers. Blood flow assessment typically refers to two techniques: measurement-based flow visualization using echocardiography or four-dimensional flow magnetic resonance imaging (4D flow MRI), and computer-based flow simulation based on computational fluid dynamics modeling. Using these methods, blood flow patterns can be visualized and quantitative measurements of mechanical stress on the walls of the ventricles and blood vessels, most notably the aorta, can be made. Thus, blood flow assessment has been enhancing the understanding of cardiac and aortic diseases; however, its introduction to clinical practice has been negligible yet. In this article, we aim to discuss the clinical applications and future directions of blood flow assessment in aortic surgery. We then provide our unique perspective on the technique's translational impact on the surgical management of aortic disease. Methods: Articles from the PubMed database and Google Scholar regarding blood flow assessment in aortic surgery were reviewed. For the initial search, articles published between 2013 and 2023 were prioritized, including original articles, clinical trials, case reports, and reviews. Following the initial search, additional articles were considered based on manual searches of the references from the retrieved literature. Key Content and Findings: In aortic root pathology and ascending aortic aneurysms, blood flow assessment can elucidate postoperative hemodynamic changes after surgical reconfiguration of the aortic valve complex or ascending aorta. In cases of aortic dissection, analysis of blood flow can predict future aortic dilatation. For complicated congenital aortic anomalies, surgeons may use preoperative imaging to perform "virtual surgery", in which blood flow assessment can predict postoperative hemodynamics for different surgical reconstructions and assist in procedural planning even before entering the operating room. Conclusions: Blood flow assessment and computational modeling can evaluate hemodynamics and flow patterns by visualizing blood flow and calculating biomechanical forces in patients with aortic disease. We anticipate that blood flow assessment will become an essential tool in the treatment planning and understanding of the progression of aortic disease.

The effect of adding an open distal anastomosis to proximal aneurysm repairs in bicuspid aortopathy.

OBJECTIVES: To determine the role of adding open distal anastomosis to proximal aortic aneurysm repairs in bicuspid aortic valve (BAV) patients. METHODS: Retrospective review was performed of 1132 patients at our Aortic Center between 2005 and 2019. Inclusion criteria were all patients diagnosed with a BAV who underwent proximal aortic aneurysm repair with open or clamped distal anastomosis. Exclusion criteria were patients without a BAV, age < 18 years, aortic arch diameter ≥ 4.5 cm, type A aortic dissection, previous ascending aortic replacement, ruptured aneurysm, and endocarditis. Propensity score matching in a 2:1 ratio (220 clamped: 121 open repairs) on 18 variables was performed. RESULTS: Median follow-up time was 45.6 months (range 7.2-143.4 months). In the matched groups, no significant differences were observed between the respective open and clamped distal anastomosis groups for Kaplan Meier 10-year survival (86.9% vs. 92.9%; p = 0.05) and landmark survival analysis after 1 year (90.6%; vs. 93.3%; p = 0.39). Overall incidence of aortic arch-related reintervention was low (n = 3 total events). In-hospital complications were not significantly different in the open with respect to the clamped repair group, including in-hospital mortality (2.5% vs. 0.5%; p = 0.13) and stroke (0% vs. 0.9%; p = 0.54). In multivariable analysis, open distal anastomosis repair was not associated with long-term mortality (Hazard Ratio (HR) 1.98; p = 0.06). CONCLUSION: We found no significant inter-group differences in survival, reintervention, or in-hospital complication rates, with low rates of mortality, and aortic arch-related reintervention, suggesting adding open distal anastomosis may not provide benefit in BAV patients undergoing proximal aortic aneurysm repairs.

Quantifying the effects of circulatory arrest on acute kidney injury in aortic surgery.

OBJECTIVES: We aim to investigate the association between parameters surrounding circulatory arrest and postoperative acute kidney injury in aortic surgery. METHODS: This is a single-center retrospective study of 1118 adult patients who underwent aortic repair with median sternotomy between January 2010 and May 2019. Acute kidney injury was defined on the basis of a modified version of the 2012 Kidney Disease Improving Global Outcomes Scale that excluded urine output. The primary outcome of interest was any stage of acute kidney injury. RESULTS: Circulatory arrest was required in 369 patients, and 307 patients (27.5%) developed acute kidney injury: stage 1 in 241 patients, stage 2 in 38 patients, and stage 3 in 28 patients. Lower-body ischemia (the period during circulatory arrest without blood flow to kidneys) duration was not associated with acute kidney injury after multivariable logistic regression (1-40 minutes, odds ratio, 0.67; 95% confidence interval, 0.43-1.04; P = .075; >40 minutes, odds ratio, 0.67; 95% confidence interval, 0.29-1.55; P = .356). Hypertension (odds ratio, 1.65; 95% confidence interval, 1.09-2.54; P = .020), preoperative estimated glomerular filtration rate (odds ratio, 0.99; 95% confidence interval, 0.98-1.00; P = .010), packed red blood cell transfusion volume (odds ratio, 1.00; 95% confidence interval, 1.00-1.00; P = .028), and nadir temperature (odds ratio, 0.93; 95% confidence interval, 0.88-0.99; P = .013) were independently associated with acute kidney injury after multivariable analysis. Although there was a positive association between lower-body ischemia duration and development of acute kidney injury with univariable cubic spline, the positive curve was flattened after adjustment for the described variables. CONCLUSIONS: Within the range of our clinical practice, prolonged lower-body ischemia duration was not independently associated with postoperative acute kidney injury, whereas nadir temperature was.

Case report: Sagliker syndrome in the patient with recurrent tertiary hyperparathyroidism due to intrathyroidal parathyroid carcinoma.

Sagliker syndrome (SS) is an extremely rare disorder that manifests in patients with advanced chronic kidney disease (CKD) undergoing programmed hemodialysis as a renal replacement therapy. Treatment of secondary hyperparathyroidism (SHPT) in these patients is still challenging. The main clinical manifestations of SS include craniofacial and fingertip deformities, dental anomalies, gingival hyperplasia, short stature, hearing loss, neurological and psychiatric impairment. The etiology and pathogenesis of SS in patients with SHPT require further clarification. However, mutations in the GNAS1, FGF23, and FGFR3 genes were described in some patients, suggesting a possible role of genetic predisposition to the syndrome. The preferred therapeutic approach for SS is surgery, but the volume of the operation is debated. The main surgical strategies include total, subtotal parathyroidectomy, or total parathyroidectomy with autotransplantation of the parathyroid gland (PG). Unfortunately, parathyroidectomy does not contribute to the regression of significant skeletal deformities. We present a unique clinical case of a patient with classical features of SS, recurrent tertiary hyperparathyroidism (THPT) after total parathyroidectomy due to intrathyroidal parathyroid carcinoma (PC).

Long-term outcome of hemiarch replacement in a proximal aortic aneurysm repair: analysis of over 1000 patients.

OBJECTIVES: The aim of this study was to investigate the impact of hemiarch replacement in patients undergoing an open repair of proximal thoracic aortic aneurysm without arch aneurysm. METHODS: A retrospective review was performed on 1132 patients undergoing proximal aortic aneurysm repair at our Aortic Center between 2005 and 2019. Inclusion criteria were all patients undergoing root or ascending aortic aneurysm repair with or without hemiarch replacement. Exclusion criteria were age <18 years, aortic arch diameter ≥4.5 cm, type A aortic dissection, previous ascending aortic replacement, ruptured aneurysm and endocarditis. Propensity score matching in a 2:1 ratio (573 non-hemiarch: 288 hemiarch) on 19 baseline characteristics was performed. The median follow-up time was 46.8 months (range 0.1-170.4 months). RESULTS: Hemiarch patients had significantly lower 10-year survival in the matched cohort (hemiarch 73.8%; 66.9-81.4%; vs non-hemiarch 86.5%; 81.1-92.3%; P < 0.001), driven by higher in-hospital mortality rate (4% vs 1%; P < 0.001). Cumulative incidence of aortic arch reintervention rates at 10 years was similarly low (hemiarch 1.0%; 0-2.5% vs non-hemiarch 1.3%; 0-2.6%, P = 0.615). Multivariate analysis with hazard ratios of the overall cohort showed hemiarch as an independent factor associated with long-term mortality (2.16; 1.42-3.27; P < 0.001) but not with aortic arch reintervention (0.76; 0.14-4.07, P = 0.750). CONCLUSIONS: Hemiarch repair may be associated with higher short-term mortality compared to non-hemiarch. Arch reintervention was rare after a repair of proximal thoracic aortic aneurysm without arch aneurysm. Our data call for larger and prospective studies to further delineate the utility of hemiarch repair in proximal aortic surgery.