Mohammad A. Zafar

Carotid Intima-Media Thickness Provides Evidence that Ascending Aortic Aneurysm Protects against Systemic Atherosclerosis

Previous evaluation of total aortic calcium score suggests that mutations promoting ascending aortic aneurysm development may protect against atherosclerosis. However, calcium score is a late indicator of atherosclerosis. We evaluated carotid intima-media thickness (IMT), an earlier marker, to assess the degree of atherosclerosis in ascending aortic aneurysm patients compared to controls. Images of right and left common carotid arteries were obtained in 52 patients with ascending aortic aneurysms and 29 controls using a Sonosite MicroMaxx ultrasound. IMT was measured with Sonosite Sonocalc IMT software, a computer-based algorithm with manual override. Six IMT measurements were obtained for each patient (right and left proximal, mid and distal common carotid artery) by a single observer and averaged. A multiple linear regression analysis was applied to test for an association between aneurysm and IMT. Patients with ascending aortic aneurysms had 0.131-mm lower carotid IMT values than controls (p = 0.0002), independent of risk factors for atherosclerosis (age, BMI, gender, family history, smoking, dyslipidemia, race, diabetes and hypertension). The average IMT was 0.50 ± 0.13 mm for individuals with aneurysm and 0.60 ± 0.11 mm for controls. Age increased the IMT by 0.005 mm per year (p = 0.0003). BMI, male gender, positive family history, dyslipidemia, diabetes and hypertension also increased the IMT, but did not reach statistical significance. This investigation provides further evidence that ascending aortic aneurysm provides protection against the development of atherosclerosis, supporting the hypothesis that proaneurysmal genetic mutations may also be antiatherogenic.

Are Thromboembolic and Bleeding Complications a Drawback for Composite Aortic Root Replacement

BACKGROUND Valve-preserving aortic root reconstruction is being performed with increasing frequency. Independent of durability concerns, enthusiasm for retaining the native valve is often championed on the presumption that composite graft replacement of the aorta will be complicated by thromboembolism and bleeding. Our goal in this late follow-up study is to determine if thromboembolism or bleeding, or both, are indeed problematic after composite aortic root replacement. METHODS Between 1995 and 2011, 306 patients (mean age, 56±14 years) underwent composite graft replacement of the aorta. St. Jude mechanical valve conduits (St. Jude Medical, St Paul, MN) were used in 242 patients, and 64 received a biologic conduit. Long-term postoperative follow-up (mean, 56 months; range, 1 to 97 months) was performed through our Aortic Database, supplemented by patient interviews and use of the Social Security Death Index. RESULTS Hospital mortality was 2.9% overall and 1.4% in the last 8 years. Kaplan-Meier curves showed freedom (±standard deviation) from bleeding, stroke, and distal embolism as 94.3%±1.7% at 5 years and 91.3%±2.4% at 10 years. Survival was 93.5%±1.8% at 5 years and 80.9%±4.6% at 10 years, which was not statistically different from that for an age- and sex-matched population in Connecticut. Freedom from reoperation of the aortic root was 99% at 10 years. CONCLUSIONS Patients had excellent survival and few thromboembolic and bleeding complications after composite aortic root replacement. These data supporting minimal morbidity in the setting of well-established durability should be used to put alternative procedures, such as valve-preserving aortic root reconstruction, into context.

Prevention of Aortic Dissection Suggests a Diameter Shift to a Lower Aortic Size Threshold for Intervention

Background: Multiple studies have quantified the relationship between aortic size and risk of dissection. However, these studies estimated the risk of dissection without accounting for any increase in aortic size from the dissection process itself. Objectives: This study aims to compare aortic size before and after dissection and to evaluate the change in size consequent to the dissection itself. Methods: Fifty-five consecutive patients (29 type A; 26 type B) with aortic dissection and incidental imaging studies prior to dissection were identified and compared to a control group of aneurysm patients (n = 205). The average time between measurement at and prior to dissection was 1.7 ± 1.9 years (1.9 ± 2.0 years mean inter-image time in the control group). A multivariate regression model controlling for growth rate, age, and gender was created to estimate the effect of dissection itself on aortic size. Results: The mean aortic sizes at and prior to dissection were 54.2 ± 7.0 and 45.1 ± 5.7 mm for the ascending aorta, and 47.1 ± 13.8 and 39.5 ± 13.1 mm for the descending aorta, respectively. The multivariable analysis revealed a significant impact of the dissection itself (p < 0.001) and estimated an increase in size of 7.65 mm (ascending aorta) and 6.38 mm (descending aorta). Thus, a proportional estimate of 82.8% (ascending aorta) and 80.8% (descending aorta) of dissections are made at a size lower than the guideline-recommended threshold (55 mm). Conclusions: The aortic diameter increases substantially due to aortic dissection itself and, thus, aortas are being dissected at clinically meaningfully smaller sizes than natural history analyses have previously suggested. These findings have important implications regarding the size at which the risk of dissection is increased.

Height alone, rather than body surface area, suffices for risk estimation in ascending aortic aneurysm

Background: In international guidelines, risk estimation for thoracic ascending aortic aneurysm (TAAA) is based on aortic diameter. We previously introduced the aortic size index (ASI), defined as aortic size/body surface area (BSA), as a predictor of aortic dissection, rupture, and death. However, weight might not contribute substantially to aortic size and growth. We seek to evaluate the height‐based aortic height index (AHI) versus ASI for risk estimation and revisit our natural history calculations. Methods: Aortic diameters and long‐term complications of 780 patients with TAAA were analyzed. Growth rate estimates, yearly complication rates, and survival were assessed. Risk stratification was performed using regression models. The predictive value of AHI and ASI was compared. Results: Patients were stratified into 4 categories of yearly risk of complications based on their ASI and AHI. ASIs (cm/m2) of ≤2.05, 2.08 to 2.95, 3.00 to 3.95 and ≥4, and AHIs (cm/m) of ≤2.43, 2.44 to 3.17, 3.21 to 4.06, and ≥4.1 were associated with a 4%, 7%, 12%, and 18% average yearly risk of complications, respectively. Five‐year complication‐free survival was progressively worse with increasing ASI and AHI. Both ASI and AHI were shown to be significant predictors of complications (P < .05). AHI categories 3.05 to 3.69, 3.70 to 4.34, and ≥4.35 cm/m were associated with a significantly increased risk of complications (P < .05). The overall fit of the model using AHI was modestly superior according to the concordance statistic. Conclusions: Compared with indices including weight, the simpler height‐based ratio (excluding weight and BSA calculations) yields satisfactory results for evaluating the risk of natural complications in patients with TAAA.

Elective surgery for ascending aortic aneurysm in the elderly: should there be an age cut-off?†

OBJECTIVES The objective of this study is to retrospectively analyse surgical outcomes in patients aged 75-79, and 80 and above. METHODS Between 2000 and 2015, 108 patients aged 75-79 (G 75 , mean age 76.9 ± 1.5years) and 72 patients aged 80 and above (G 80 , mean age 82.2 ± 2.1years) underwent elective aneurysm repair. Operative outcome and survival was compared with 727 contemporary younger counterparts aged <75 years (G Ctrl , mean age 56.6 ± 11.7years). RESULTS Postoperatively, patients with advanced age showed a higher incidence of prolonged ventilation (G 80 21.4%, G 75 8.4%, G Ctrl 2.9%; P < 0.001), low cardiac output syndrome (G 80 11.4%, G 75 1.9%, G Ctrl 2.2%; P = 0.001), multi organ failure (G 80 2.9%, G 75 0%, G Ctrl 0.1%; P = 0.022), haemofiltration (G 80 8.6%, G 75 0.9%, G Ctrl 0.6%; P < 0.001), and infection (G 80 10.0%, G 75 6.5%, G Ctrl 3.5%; P = 0.017). Operative mortality was significantly increased in the elderly (G 80 11.1%, G 75 3.7%, G Ctrl 1.4%; P < 0.001). Mid-term survival differed significantly between the surgical groups. Multivariate regression analysis precluded age as an independent predictor of operative mortality. CONCLUSIONS Elderly patients showed a higher operative risk compared to their younger counterparts. However, age per se is no suitable indicator of surgical risk and well-selected patients with large threatening aneurysms may benefit from intervention.

A systematic review on management of nutcracker syndrome

OBJECTIVE Although nutcracker syndrome (NS) is rare, patients presenting with symptoms or signs and anatomic compression of the left renal vein (LRV) can be considered for intervention. Open, laparoscopic, and endovascular techniques have been developed to decrease the venous outflow obstruction of the LRV. The paucity of data regarding the management of this uncommon disease process poses a challenge for adequate recommendations of the best treatment modality. Herein, we aim to present a systematic review for the management of NS. METHODS We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards to systematically search the electronic databases of MEDLINE from October 1982 to July 2017 for articles about the management of NS. Included were studies in English, Spanish, and German in all age groups. RESULTS The literature search provided 249 references. After abstract and full review screening for inclusion, 17 references were analyzed. Eight (47%) described the open surgical approach. The LRV transposition was the most commonly reported technique, followed by renal autotransplantation. Seven (41.11%) described the endovascular technique of stent implantation, and two (11.7%) described the minimally invasive laparoscopic extravascular stent implantation. CONCLUSIONS NS is a rare entity. Multiple techniques have been developed for the treatment of this condition. However, the rarity of this syndrome, the paucity of data, and the short-term follow-up of the existing evidence are the disadvantages that prevent recommendations for the best treatment strategy. Up to now, open surgical intervention, specifically LRV transposition, has been considered by some experts the mainstay for treatment of NS. The endovascular approach is gaining strength as more evidence has become available. However, the long-term patency and durability of this approach remain to be elucidated. Therefore, careful selection of patients is necessary in recommending this technique.

Descending Threshold for Ascending Aortic Aneurysmectomy: Is It Time for a “Left-Shift” in Guidelines?

&NA; Current guidelines on the management of thoracic aortic disease recommend that the ascending aorta be replaced when it reaches the size of 5.5 cm. Recently emerging data suggest that this criterion may need to be shifted to the left, signifying a recommendation to operate on patients with smaller aortic sizes. The data that support the need for a leftward shift in the guidelines include (1) novel and more granular data on the natural history of ascending aortic aneurysm between 5 and 6 cm showing that 2 hinge risk points exist—one at 5.25 cm, and the other at 5.75 cm; (2) aortic diameter before the moment of aortic dissection is at least 7 mm smaller than postdissection aortic size; (3) the advent of a semiautomated centerline method of imaging assessment seems to underestimate true ascending aortic size; (4) aortic surgery in the present era is very safe and its benefits outweigh the associated risks; (5) genetic testing via high‐throughput next‐generation sequencing identifies genetic defects responsible for aortic catastrophes at smaller aortic sizes; and (6) familial aortic dissection occurrence suggests that family members of an aortic dissection victim who harbor a sizable aneurysm should be operated on regardless of aortic size.

Does BioGlue contribute to anastomotic pseudoaneurysm after thoracic aortic surgery

BACKGROUND Although bovine serum albumin-glutaraldehyde glue (BioGlue®) has been successfully used as a hemostatic adjunct in aortic surgical procedures, there are reports that it may lead to anastomotic pseudoaneurysm formation. We seek to examine if the use of BioGlue is associated with a high incidence of anastomotic pseudoaneurysm formation following surgical repair of thoracic aortic disease. METHODS We reviewed the medical records and follow-up computed tomography (CT) scans of patients from 2001 to 2015 in whom BioGlue was used during surgical repair of thoracic aortic disease to detect postoperative anastomotic pseudoaneurysm formation. RESULTS A total of 233 patients with BioGlue use were identified. Mean age was 63.5±14.0 years (median 66; range 14-88; 25-75%, IQR 54-74 years) and 149 were male (63.9%). Surgical indication was thoracic aortic aneurysm in 169 (72.5%) patients, aortic dissection in 49 (21.0%), intramural hematoma in 9 (3.9%), penetrating aortic ulcer in 3 (1.3%) and other in 3 (1.3%). Emergency/urgent surgery was performed in 68 cases (29.2%). Operative mortality was 7.3% (17/233). Re-exploration for bleeding and neurologic deficits occurred in 24 (10.3%) and 21 (9.0%) patients respectively. All operative survivors were followed (100%, 216/216) and CT follow-up was available in 81.9% (177/216) for a mean duration of 2.4 years (median 0.6; 25-75% IQR 0.2-3.6 years). Anastomotic pseudoaneurysm was detected in 1 patient (0.6%) at 3 years postoperatively. This was an elderly female with extremely frail tissues who underwent a reoperative ascending and arch replacement for dissection. CONCLUSIONS The use of BioGlue in thoracic aortic surgery was not associated with excess incidence of anastomotic pseudoaneurysm formation following surgical repair of thoracic aortic disease. Its use need not be discouraged on this basis.

Antithrombotic Therapy after Bioprosthetic Aortic Valve Replacement: A Therapeutic Morass

Valvular heart disease is a common pathologic condition that affects 6 million people in the United States and more than 100 million worldwide. The most common valvular disorder is aortic stenosis. Current American and European guidelines recommend surgical management for symptomatic aortic stenosis with low risk of perioperative complications and endovascular intervention for high-risk patients with multiple comorbidities. Considering the increasing volume of aortic valve replacement (AVR) with biological valves, it is very important to select the appropriate anticoagulant after surgical AVR. In this article, we review the impact of anticoagulation on immediate and remote complications after AVR.

Histology of Aortic Disease and Progression of Aortic Dissection From Acute to Chronic

Abstract Acute Stanford type A dissections rarely progress to the chronic state naturally as a result of early surgical intervention. In contrast, medical therapy is the treatment of choice for uncomplicated acute type B dissections, explaining their preponderance in transitioning to the chronic state. In this chapter, in addition to the histology and histopathology of the aorta, we elaborate the dynamic histopathological and morphological changes occurring in the aorta that characterize the temporal course of the evolution from acute to chronic dissection.