Fate of the unoperated ascending thoracic aortic aneurysm: three-decade experience from the Aortic Institute at Yale University.

AIMS: This study aims to outline the 'true' natural history of ascending thoracic aortic aneurysm (ATAA) based on a cohort of patients not undergoing surgical intervention. METHODS AND RESULTS: The outcomes, risk factors, and growth rates of 964 unoperated ATAA patients were investigated, over a median follow-up of 7.9 (maximum of 34) years. The primary endpoint was adverse aortic events (AAE), including dissection, rupture, and aortic death. At aortic sizes of 3.5-3.9, 4.0-4.4, 4.5-4.9, 5.0-5.4, 5.5-5.9, and ≥6.0 cm, the average yearly risk of AAE was 0.2%, 0.2%, 0.3%, 1.4%, 2.0%, and 3.5%, respectively (P < 0.001), and the 10-year survival free from AAE was 97.8%, 98.2%, 97.3%, 84.6%, 80.4%, and 70.9%, respectively (P < 0.001). The risk of AAE was relatively flat until 5 cm of aortic size, at which it began to increase rapidly (P for non-linearity <0.001). The mean annual growth rate was estimated to be 0.10 ± 0.01 cm/year. Ascending thoracic aortic aneurysms grew in a very slow manner, and aortic growth over 0.2 cm/year was rarely seen. Multivariable Cox regression identified aortic size [hazard ratio (HR): 1.78, 95% confidence interval (CI): 1.50-2.11, P < 0.001] and age (HR: 1.02, 95% CI: 1.00-1.05, P = 0.015) as significant independent risk factors for AAE. Interestingly, hyperlipidemia (HR: 0.46, 95% CI: 0.23-0.91, P = 0.025) was found to be a significant protective factor for AAE in univariable Cox regression. CONCLUSION: An aortic size of 5 cm, rather than 5.5 cm, may be a more appropriate intervention criterion for prophylactic ATAA repair. Aortic growth may not be an applicable indicator for intervention.

Synergistic Integration of Deep Neural Networks and Finite Element Method with Applications of Nonlinear Large Deformation Biomechanics.

Patient-specific finite element analysis (FEA) holds great promise in advancing the prognosis of cardiovascular diseases by providing detailed biomechanical insights such as high-fidelity stress and deformation on a patient-specific basis. Albeit feasible, FEA that incorporates three-dimensional, complex patient-specific geometry can be time-consuming and unsuitable for time-sensitive clinical applications. To mitigate this challenge, machine learning (ML) models, e.g., deep neural networks (DNNs), have been increasingly utilized as potential alternatives to finite element method (FEM) for biomechanical analysis. So far, efforts have been made in two main directions: (1) learning the input-to-output mapping of traditional FEM solvers and replacing FEM with data-driven ML surrogate models; (2) solving equilibrium equations using physics-informed loss functions of neural networks. While these two existing strategies have shown improved performance in terms of speed or scalability, ML models have not yet provided practical advantages over traditional FEM due to generalization issues. This has led us to the question: instead of abandoning or replacing the traditional FEM framework that can reliably solve biomechanical problems, can we integrate FEM and DNNs to enhance performance? In this study, we propose a synergistic integration of DNNs and FEM to overcome their individual limitations. Using biomechanical analysis of the human aorta as the test bed, we demonstrated two novel integrative strategies in forward and inverse problems. For the forward problem, we developed DNNs with state-of-the-art architectures to predict a nodal displacement field, and this initial DNN solution was then updated by a FEM-based refinement process, yielding a fast and accurate computing framework. For the inverse problem of heterogeneous material parameter identification, our method employs DNN as a regularizer of the spatial distribution of material parameters, aiding the optimizer in locating the optimal solution. In our demonstrative examples, despite that the DNN-only forward models yielded small displacement errors in most test cases; stress errors were considerably large, and for some test cases, the peak stress errors were greater than 50%. Our DNN-FEM integration eliminated these non-negligible errors in DNN-only models and was magnitudes faster than the FEM-only approach. Additionally, compared to FEM-only inverse method with errors greater than 50%, our DNN-FEM inverse approach significantly improved the parameter identification accuracy and reduced the errors to less than 1%.

Evidence Accumulates: Patients with Ascending Aneurysms Are Strongly Protected from Atherosclerotic Disease.

Ascending thoracic aortic aneurysms may be fatal upon rupture or dissection and remain a leading cause of death in the developed world. Understanding the pathophysiology of the development of ascending thoracic aortic aneurysms may help reduce the morbidity and mortality of this disease. In this review, we will discuss our current understanding of the protective relationship between ascending thoracic aortic aneurysms and the development of atherosclerosis, including decreased carotid intima-media thickness, low-density lipoprotein levels, coronary and aortic calcification, and incidence of myocardial infarction. We also propose several possible mechanisms driving this relationship, including matrix metalloproteinase proteins and transforming growth factor-ß.

"Big Data" Analyses Underlie Clinical Discoveries at the Aortic Institute.

This issue of the Yale Journal of Biology and Medicine (YJBM) focuses on Big Data and precision analytics in medical research. At the Aortic Institute at Yale New Haven Hospital, the vast majority of our investigations have emanated from our large, prospective clinical database of patients with thoracic aortic aneurysm (TAA), supplemented by ultra-large genetic sequencing files. Among the fundamental clinical and scientific discoveries enabled by application of advanced statistical and artificial intelligence techniques on these clinical and genetic databases are the following: From analysis of Traditional "Big Data" (Large data sets). 1. Ascending aortic aneurysms should be resected at 5 cm to prevent dissection and rupture. 2. Indexing aortic size to height improves aortic risk prognostication. 3. Aortic root dilatation is more malignant than mid-ascending aortic dilatation. 4. Ascending aortic aneurysm patients with bicuspid aortic valves do not carry the poorer prognosis previously postulated. 5. The descending and thoracoabdominal aorta are capable of rupture without dissection. 6. Female patients with TAA do more poorly than male patients. 7. Ascending aortic length is even better than aortic diameter at predicting dissection. 8. A "silver lining" of TAA disease is the profound, lifelong protection from atherosclerosis. From Modern "Big Data" Machine Learning/Artificial Intelligence analysis: 1. Machine learning models for TAA: outperforming traditional anatomic criteria. 2. Genetic testing for TAA and dissection and discovery of novel causative genes. 3. Phenotypic genetic characterization by Artificial Intelligence. 4. Panel of RNAs "detects" TAA. Such findings, based on (a) long-standing application of advanced conventional statistical analysis to large clinical data sets, and (b) recent application of advanced machine learning/artificial intelligence to large genetic data sets at the Yale Aortic Institute have advanced the diagnosis and medical and surgical treatment of TAA.

Long-term risk of arch complications in Loeys Dietz syndrome patients undergoing proximal ascending aortic replacement.

PURPOSE: Loeys-Dietz syndrome (LDS) is a rare connective tissue disorder. In LDS patients with normal arch morphology, whether the arch should be prophylactically replaced at the time of proximal aortic replacement remains unknown. We evaluated the risk of long-term arch complications in genetically confirmed LDS patients who underwent proximal ascending aortic replacement. METHODS: We retrospectively reviewed the records of patients with LDS who have been followed at our institution between 1994 and 2020. Patients were only included if whole exome genetic testing confirmed a mutation in an LDS-causing gene (TGFBR1, TGFBR2, SMAD3, TGFB2, or TGFB3). Mutations were categorized as pathogenic, benign, or of unknown significance. We collected demographic information, aortic dimensions, comorbidities, mortality, and operative course from patients' charts. Descriptive statistics and freedom from reoperation plots were generated. RESULTS: Of the 18 patients with a mutation in an LDS-causing gene, 15 had known pathogenic variants, two had mutations of unknown significance, and one had a benign genetic variant. For the 15 patients with confirmed pathogenic variants of LDS the median follow-up duration was 5 years (interquartile range [IQR]: 4-8). Eleven patients underwent ascending aortic replacements (AAR) ± aortic valve replacement. Two patients required an additional operation; one required arch and staged elephant trunk for a dissection 18 years post-AAR and the other patient required an isolated descending aortic replacement for dissection 5 years post-AAR. Among patients who underwent surgery, the median ascending aortic diameter at intervention was 5.0 cm (IQR: 4.3-5.3). There was no surgical or late follow-up mortality observed for any of the 18 patients in the study. CONCLUSION: LDS patients who underwent proximal aortic replacement appeared to have low long-term risk of arch complications. While our study is somewhat limited by its sample size and follow-up duration, it suggests that routine prophylactic total arch replacement may not be warranted in LDS patients with nonaneurysmal aortic arches.

Interstage mortality in two-stage elephant trunk surgery.

PURPOSE: Diffuse mega-aorta is challenging. Prior studies have raised concerns regarding the safety of the open two-stage elephant trunk (ET) approach for extensive thoracic aortic aneurysm (TAA), specifically in regard to interstage mortality. This study evaluates the safety of the two-stage ET approach for management of extensive TAA. METHODS: Between 2003 and 2018, 152 patients underwent a Stage I ET procedure by a single surgeon (mean age 64.5 ± 14.8). Second stage ET procedure was planned in 60 patients (39.4%) and to-date has been performed in 54 patients (90%). (in the remaining patients, the ET was prophylactic for the long-term, with no plan for near-term utilization). RESULTS: In-hospital mortality after the Stage I procedure was 3.3% (5/152). In patients planned for Stage II, the median interstage interval was 5 weeks (range: 0-14). Of the remaining six patients with planned, but uncompleted Stage II procedures, five patients expired from various causes in the interval period (interstage mortality of 8.3%). There were no cases of aortic rupture in the interstage interval. Stage II was completed in 58 patients (including four unplanned) with a 30-day mortality of 10.3% (6/58). Seven patients developed strokes after Stage II (12%), and three patients (5.1%) developed paraplegia. CONCLUSIONS: The overall mortality, including Stage I, interstage interval, and Stage II was 18.6%. This substantial cumulative mortality for the open two-staged ET approach for the treatment of extensive TAA appears commensurate with the severity of the widespread aortic disease in this patient group. Fear of interstage rupture should not preclude the aggressive Two-Stage approach to the management of extensive TAA.

Natural history and management of Kommerell's diverticulum in a single tertiary referral center.

OBJECTIVE: The Kommerell diverticulum (KD) is an extremely rare developmental abnormality of the aorta related to an aberrant subclavian artery (ASCA). The objective of our study was to review the natural history of KD and ASCA using our single-center experience in diagnosing and managing KD and ASCA. METHODS: A retrospective review of the Yale radiological database from January 1999 to December 2016 was performed. Only patients with KD/ASCA and a computed tomography (CT) scan of the chest were selected for review. The primary goal was to examine the natural history of KD and ASCA and the secondary goals were to review the management and outcomes of those patients treated for KD and ASCA. RESULTS: There were 75 patients with KD/ASCA identified, with a mean age of 63 ± 19 years; 49 were female (65%). On CT scans, left- and right-sided aortas were present in 47 (63%) and 28 (37%) patients. A right ASCA or a left ASCA were present in 47 (63%) and 28 (37%) patients. Six patients were symptomatic on presentation. Symptoms included dysphagia, chest or back pain, and emboli to the fingers. The mean KD diameter was 21.8 ± 6.0 mm and the distance to the opposite aortic wall (DAW) was 48.3 ± 10.8 mm. Sixty-six patients were followed for a mean of 31.7 ± 32.5 months. One patient ruptured without repair. Nine patients underwent operative intervention, including eight open and one endovascular repair. Complications from operative intervention included ischemic stroke with hemorrhagic transformation, deep vein thrombosis and pneumonia. The mean growth rate for KD and DAW was 1.45 ± 0.39 mm/year and 2.29 ± 0.47 mm/year, respectively. On multivariable regression analysis, hypertension was a predictor of growth of DAW (P = .03). CONCLUSIONS: KD is uncommon and shows a female predominance. The diverticulum grows, albeit slowly (KD and DAW growth rates of 1.45 ± 0.39 mm/year and 2.29 ± 0.47 mm/year). Most patients are asymptomatic, but dysphagia, chest/back pain, and distal emboli may occur. Rupture is rare. Symptomatic patients should be operated. Asymptomatic patients can be followed with serial CT scans.

Cine-Computed Tomography for the Evaluation of Prosthetic Heart Valve Function.

BACKGROUND: After aortic valve replacement (AVR), suspected prosthetic valve dysfunction (mechanical or biological) may arise based on echocardiographic transvalvular velocities and gradients, leading to reoperative surgical intervention being considered. Our experience has found that 4-dimensional (space and time) image reconstruction of ECG-gated computed tomography, termed cine-CT, may be helpful in such cases. We review and illustrate our experience. METHODS: Twenty-seven AVR patients operated previously by a single surgeon (who performs >100 AVRs/year) were referred for repeat evaluation of suspected aortic stenosis (AS) based on elevated transvalvular velocities and gradients. The patients were fully evaluated by cine-CT. RESULTS: In all but 2 cases, the cine-CT strikingly and visually confirmed normal leaflet function and excursion, with no valve thrombosis, restriction by pannus, or obstruction by clot. In only 2 cases did cine-CT reveal decreased mechanical valve leaflet excursion. Repeat surgery was required in only 1 case while all other patients continued clinically without cardiac events. CONCLUSIONS: Echocardiography is an extraordinarily useful tool for the evaluation of prosthetic valve function. Increased pressure recovery beyond the valve and other factors may occasionally lead to exaggerated gradients. Cine-CT is emerging as an extremely valuable tool for further evaluation of suspected prosthetic valve AS. Our experience has been extremely helpful, as is shown in the dramatically reassuring images.

A systematic review and meta-analysis of isolated abdominal aortic dissection.

OBJECTIVE: Isolated abdominal aortic dissection (IAAD) has remained poorly understood because of its rarity. We explored the prevalence, clinical characteristics, risk factors, imaging characteristics, and treatment strategy of IAAD to facilitate its diagnosis and treatment. METHODS: We performed a meta-analysis of 17 studies, with single-arm-based and network meta-analysis as the main data synthesis method. The Medline, Embase, and Cochrane library were searched from their inception to July 2018. A total of 9163 patients with aortic disease were enrolled, with IAAD identified in 491 patients. RESULTS: The pooled prevalence of IAAD among cases of aortic dissection overall, type B aortic dissection, and type A aortic dissection was 1.7% (95% confidence interval [CI], 0.9%-3.4%), 4.1% (95% CI, 2.5%-6.6%), and 2.0% (95% CI, 0.7%-3.9%), respectively. Abdominal pain was the most common symptom (50.8%), followed by back pain (30.5%), and chest pain (21.7%). Up to 41.0% of the patients with IAAD did not present with any clinical symptoms, and up to 71.0% of these patients had negative findings on physical examination. The top three most prevalent risk factors for IAAD were hypertension, hyperlipidemia, and smoking. Most cases of IAAD were limited to the aorta inferior to the renal arteries (81.7%), and the average aortic diameter was 4 cm. No statistically significant difference was observed between open surgery, endovascular aortic repair, and conservative management for both early and late mortality. CONCLUSIONS: The results from the present meta-analysis regarding IAAD support the following conclusions and recommendations. First, IAAD is rare and predominantly affects males. Second, symptoms (pain) might or might not be present, and physical findings will rarely be found on abdominal examination. Third, hypertension is the most prevalent risk factor. Fourth, most cases IAAD will be infrarenal. Finally, a complication-specific approach, similar to that for type B aortic dissection, would be appropriate.

Screening for Intracranial Aneurysms in Patients with Thoracic Aortic Aneurysms.

INTRODUCTION: A higher prevalence of intracranial aneurysms (IAs) has been previously reported by retrospective studies in patients with thoracic aortic aneurysms (TAAs). The goal of this study was to evaluate the prevalence of IAs in a large cohort of prospectively screened patients with TAAs and identify potential risk factors. METHODS: Patients above 18 years with TAAs who were prospectively screened for IAs using computed tomographic angiogram/magnetic resonance angiogram over a 9-year period were included in the study. Patient demographics, comorbidities, aortic, and IA locations and sizes were analyzed. Univariate analysis was performed with the χ2 test for categorical variables and the Student t test or ANOVA for continuous variables. RESULTS: Five hundred and fifty-four patients with TAAs were prospectively screened for IAs and included in the study. Thirty-one IAs were identified in 27 patients (prevalence = 4.9%). The prevalence of IAs in patients with ascending TAAs was 4.51% and in descending TAAs was 9.09%. Twenty out of 31 IAs were 2 mm in size, 6/31 were 3 mm, and 5/31 were 4 mm in size. Hypertension was associated with an increased prevalence of IAs, especially in patients with descending TAAs. DISCUSSION/CONCLUSION: The prevalence of IAs in patients with TAAs may not be as high as described in previous retrospective studies. Our results suggest that the prevalence of IAs in patients with TAAs is similar to the general population. Study results reveal that IAs have a higher correlation to patients with descending TAAs, although not statistically significant. Hypertension was found to be a statistically significant risk factor for IAs in patients with TAAs.

Isolated Tricuspid Valvectomy: A Series of cases with Intravenous Drug Abuse Associated Tricuspid Valve Endocarditis.

INTRODUCTION: Surgical management for tricuspid valve (TV) endocarditis is usually TV repair or replacement. When repair is not feasible, and concerns for patient recidivism preclude TV replacement, tricuspid valvectomy without replacement is an option to alleviate symptoms and allow time for addiction management. METHODS: We reviewed our institution's experience with isolated tricuspid valvectomy for cases of intravenous drug use (IVDU)-associated endocarditis (n = 7) from 2009 to 2017. RESULTS: The decision for tricuspid valvectomy was based on each patient's comorbid condition and realization of active IVDU. This intervention resulted in 100% perioperative and mid-term survival with a mean follow-up of 25.4 months. One patient required a valve replacement in the long term only after appropriate substance abuse management was completed. CONCLUSION: Cardiac surgeons increasingly encounter patients with active endocarditis who suffer from IVDU addiction. Drug addiction increases the risk for recurrent endocarditis and requires an effective management plan. Multidisciplinary endocarditis care teams may play a pivotal role in improving outcomes by better addressing addiction treatment.

Routine anterior spinal artery visualization prior to descending and thoracoabdominal aneurysm repair: High detection success.

BACKGROUND: Paraplegia is adevastating complication of open descending (DTAA) and thoracoabdominal aortic aneurysm (TAAA) repair. Despite major advances in imaging and surgical techniques, paraplegia continues to be problematic. We present our experience with routine application of enhanced imaging techniques to detect the anterior spinal artery (ASA) before DTAA and TAAA repair. METHODS: We retrospectively reviewed 177 patients with DTAA and TAAA who underwent imaging to detect the ASA before open surgical repair. High definition CT angiography (CTA) and dual energy CT scanning (DECT) were our modalities of choice with angiography used earlier and magnetic resonance angiography (MRA) used when CT was contraindicated. Descriptive statistics and χ2 analyses were conducted. RESULTS: The imaging protocol successfully detected the level of the ASA in 132 (74.5%) patients, utilizing CTA in 67, DECT in 28, spinal angiography in 31, and MRA in 6. Cross sectional modalities with advanced visualization technique (CT, DECT, and MRA) were more successful at detecting the ASA than angiography (80.72%, 82.35%, 75% vs 59.62%, respectively, P = .04). Concerted efforts were made not to leave the operating room without continuity of the ASA with the circulation (via limited resection, beveled anastomosis, or reimplantation). Transient lower extremity weakness was observed in 11 (6.2%) patients, and permanent paraplegia in 2 (1.12%) patients. CONCLUSION: Modern imaging technology provides multiple methodologies highly successful at detecting the ASA. The ASA can then be preserved intraoperatively, contributing to low paraplegia rates. We strongly recommend routine application of this technology to arm the surgeon with precise information about the specific patient's spinal cord blood supply.

Fate of preserved bicuspid valves at time of ascending aortic aneurysmectomy.

BACKGROUND: The fate of the spared bicuspid aortic valve in patients undergoing ascending aortic aneurysm surgery is relatively unknown. Our institutional policy has been to replace all aortic valves with significant abnormalities, as evidenced by intraoperative transesophageal echocardiography or direct visual inspection. In this study, we elaborate our experience regarding the long-term fate of preserved bicuspid aortic valves after ascending aortic aneurysm extirpation. MATERIALS AND METHODS: From 2000 to 2018, 407 consecutive ascending aortic aneurysm patients with concomitant bicuspid aortic valves underwent surgery by a single surgeon at our institution. Among these, 23 (5.65%) patients did not have their valve replaced, forming the study group. Postoperative and preoperative echocardiograms were compared to determine changes in valve function. RESULTS: Follow-up was complete in 100% of patients. The average time between preoperative and postoperative echocardiograms was 4.50 ± 4.09 years (0.19-15.63). Aortic stenosis or regurgitation changed from none to mild in 5 (21.7%) of patients, with an average echocardiographic interval follow-up of 3.08 years, and from none to severe in 2 (8.7%), with an interval of 11.7 years. One patient required reoperation, including aortic valve replacement, during follow-up. CONCLUSION: Bicuspid aortic valves free of aortic stenosis or insufficiency before surgery and "healthy" appearing at surgery can safely be preserved.

Targeted genetic analysis in a large cohort of familial and sporadic cases of aneurysm or dissection of the thoracic aorta.

PURPOSE: Thoracic aortic aneurysm/aortic dissection (TAAD) is a disorder with highly variable age of onset and phenotype. We sought to determine the prevalence of pathogenic variants in TAAD-associated genes in a mixed cohort of sporadic and familial TAAD patients and identify relevant genotype-phenotype relationships. METHODS: We used a targeted polymerase chain reaction and next-generation sequencing-based panel for genetic analysis of 15 TAAD-associated genes in 1,025 unrelated TAAD cases. RESULTS: We identified 49 pathogenic or likely pathogenic (P/LP) variants in 47 cases (4.9% of those successfully sequenced). Almost half of the variants were in nonsyndromic cases with no known family history of aortic disease. Twenty-five variants were within FBN1 and two patients were found to harbor two P/LP variants. Presence of a related syndrome, younger age at presentation, family history of aortic disease, and involvement of the ascending aorta increased the risk of carrying a P/LP variant. CONCLUSION: Given the poor prognosis of TAAD that is undiagnosed prior to acute rupture or dissection, genetic analysis of both familial and sporadic cases of TAAD will lead to new diagnoses, more informed management, and possibly reduced mortality through earlier, preclinical diagnosis in genetically determined cases and their family members.

Natural history and management of splanchnic artery aneurysms in a single tertiary referral center.

OBJECTIVE: Splanchnic artery aneurysms (SAAs) are rare, and little is known about their natural history and management. We reviewed our single-center experience in managing this population of patients. METHODS: A retrospective review of the Yale radiologic database from January 1999 to December 2016 was performed. Only patients with an SAA and a computed tomography scan of the abdomen were selected for review. Demographics of the patients, aneurysm characteristics, management, postoperative complications, and follow-up data were collected. Our primary outcomes included aneurysm growth rate and risk of rupture in those patients managed nonoperatively and morbidity and mortality of those SAA patients who underwent operative intervention. RESULTS: There were 122 patients with 138 SAAs identified; 77 were male (62%), with a mean age of 66 years (range, 25-94 years). On computed tomography, 56 (45%) had previously diagnosed or concomitant aneurysms elsewhere. Of the patients managed nonoperatively, 101 patients (79%) had 108 SAAs; in the operative intervention group, 25 (21%) patients had 30 SAAs. The mean overall vessel diameter was 1.76 ± 0.83 cm. The diameter of observed and operatively repaired SAAs was 1.58 ± 0.56 cm and 2.41 ± 1.23 cm, respectively (P = .00001). Mean follow-up was 50 ± 42 months for nonoperative management without any adverse events related to SAA, including 10 patients with SAA >2.0 cm. The mean observed growth rate for SAA was 0.064 ± 0.18 cm/y. All symptomatic patients who presented with severe abdominal pain (n = 11 [44%]) underwent operative intervention. Five patients presented with a ruptured SAA (3.6%; range, 2.3-5.0 cm); all of them except one underwent operative intervention. Other indications for repair included large size in seven, rapid growth in two, other open abdominal surgical procedures in two, multiple aneurysms in one, and desire to pursue fertility treatment in one. Operative repair included 14 (56%) endovascular embolizations and 11 (44%) open abdominal operations. After endovascular embolization, two patients underwent abdominal operation for hemorrhage and splenectomy. Open repairs included bypasses in six, splenectomy in two, resection in two, and plication in one. Two patients had postoperative acute kidney injury that resolved and one died of multisystem organ failure. One bypass occluded without sequelae. On multivariable regression analysis, female sex (P = .02) was associated with faster growth rate, and a history of smoking (P = .04) was associated with slower growth rate. CONCLUSIONS: It seems reasonable to observe asymptomatic patients with an SAA <2.0 cm because of the slow growth rate (0.064 ± 0.18 cm/y) and benign behavior. When intervention is needed, both open and endovascular options should be considered.

Natural history and management of renal artery aneurysms in a single tertiary referral center.

OBJECTIVE: Although renal artery aneurysms (RAAs) are uncommon, several large reports have been published indicating their benign natural history. The objective of our study was to review our single-center experience managing this disease entity. METHODS: A retrospective review of the Yale radiologic database from January 1999 to December 2016 was performed. Only patients with RAA and a computed tomography scan of the abdomen were selected for review. Demographics of the patients, aneurysm characteristics, management, postoperative complications, and follow-up data were collected. RESULTS: There were 241 patients with 259 RAAs identified, with a mean age of 69 years (range, 35-100 years); 147 were female (61%). On computed tomography, aneurysms were solitary and right sided in 224 (86%) and 159 (61%), respectively; 64 (27%) patients had aneurysms elsewhere. The breakdown of RAAs by location was as follows: renal bifurcation in 84 (32%), renal pelvis in 77 (30%), distal renal artery in 58 (22%), mid renal artery in 34 (13%), and proximal renal artery in 6 (2%). Five patients had symptoms that were attributed to the RAA and underwent operative repair; all others were observed without an operation. Symptoms in the operative repair group included flank pain in four and uncontrolled hypertension in one. The mean overall diameter of the RAAs was 1.22 ± 0.49 cm. The diameter of operatively repaired and observed RAAs was 1.84 ± 0.55 cm and 1.21 ± 0.48 cm, respectively (P = .002). Operative repair included four coil embolizations and one open resection. There were no renal function changes in any of these patients after operation and no other complications. Mean follow-up was 41 ± 35 months for patients in the group that was observed; 18 of these RAAs were >2 cm, and none ruptured. On multivariable regression analysis, female sex (P = .0001), smoking history (P = .00007), left-sided RAA (P = .03), and main renal artery location (P = .03) were inversely related to growth, whereas a history of hypertension was directly related to growth rate (P = .01). The mean growth rate for RAAs was 0.017 ± 0.052 cm/y. CONCLUSIONS: RAAs tend to have a benign natural history. Although previous reports have not identified any factors that contribute to RAA growth, we observed that RAA location, sex, smoking history, and hypertension may have an impact on growth rates. No ruptures were observed. Operative repair at our institution was rare, with no morbidity or mortality. Observation of RAAs over time seems feasible in the asymptomatic patient with a small RAA.

Natural history of aneurysmal aortic arch branch vessels in a single tertiary referral center.

OBJECTIVE: Little is known about the natural history and management of aneurysmal aortic arch branch vessels (AABVs). The objectives of this study were to assess the natural history of aneurysmal AABVs and to examine the outcomes of operative intervention. METHODS: A retrospective review of the Yale radiologic database from 1999 to 2016 was performed. Only those patients with an aneurysmal AABV and a computed tomography scan were selected for review. Patients' demographics, aneurysm characteristics, management, and follow-up information were collected. RESULTS: There were 105 patients with 147 aneurysmal AABVs; 76 were male (72%), with a mean age of 70 years (range, 17-93 years). We identified 63 innominate, 50 left subclavian, 30 right subclavian, and 4 common carotid artery aneurysms. On computed tomography, 65 (62%) had aortic aneurysms and six (6%) had suffered an aortic dissection. Most were asymptomatic (104 [99%]); one had chest pain and an enlarging swollen mass. Twelve (11%) patients underwent operative repair (OR) for 12 aneurysmal AABVs because of symptoms, growth, or concomitant aortic operations; 93 (89%) were observed in the no operative repair (NOR) group with cross-sectional imaging. The overall mean vessel diameter was 2.08 ± 0.68 cm. The mean diameters in the OR and NOR groups were 3.32 ± 1.24 cm and 1.97 ± 0.46 cm, respectively (P = .002). OR included nine bypasses with resection, two stent grafts, and one resection without reconstruction. Two patients developed postoperative hemorrhage requiring re-exploration, one patient developed stent thrombosis, and one patient required pseudoaneurysm repair 20 years after index operation. Mean follow-up was 52 ± 51 months for the NOR group, with no ruptures or emboli. The growth rate was 0.04 ± 0.10 cm/y. On multivariable regression analysis, a descending aortic aneurysm (P = .041) and a left subclavian artery aneurysm (P = .016) were associated with higher growth rates, whereas height was associated with a lower growth rate (P = .001). CONCLUSIONS: Aneurysmal AABVs tend to have a benign natural history with slow growth rates and low rates of complications, including rupture and embolization. We recommend expectant observational management for small, incidentally detected aneurysms.