Computed Tomography Imaging Measurements as a Surrogate for Clinical Outcomes After Surgical Management of Acute Type A Aortic Dissection: A Systematic Review.

BACKGROUND: Postoperative computed tomography imaging surveillance is an essential component of care after acute type A aortic dissection (ATAAD) repair. Prognostic imaging factors after ATAAD repair have not been systematically reviewed. METHODS AND RESULTS: We performed a systematic review to summarize postoperative computed tomography measurements including aortic diameter, cross-sectional area, volume, growth rate, and false lumen thrombosis in addition mid- to long-term clinical outcomes after ATAAD repair. Searches were conducted in Medline, Embase, and CENTRAL in October 2022. Studies were included if they reported clinical outcomes such as mortality or aortic reintervention after 1 year and included aforementioned computed tomography findings. Studies of chronic aortic dissection and studies of exclusive patient populations such as those with connective tissue diseases were excluded. Risk of bias was assessed with the Newcastle-Ottawa Scale. Searches retrieved 6999 articles. Sixty-eight studies met inclusion criteria (7885 patients). Extended repairs were associated with improved false lumen thrombosis, decreased aortic growth rate, and decreased rates of reintervention but not improved survival. Growth rates of the aorta post-ATAAD repair were highest in the descending thoracic aorta. The most frequent prognostic imaging factors reported were a patent/partially thrombosed false lumen and postoperative aortic diameter >40 to 45 mm. CONCLUSIONS: Established measurements of positive aortic remodeling, including complete false lumen thrombosis and stabilization of postoperative aortic diameter and growth are the most studied prognostic indicators for improved clinical outcomes after ATAAD repair. Growth rate of the aorta remains significant after ATAAD repair. Future studies should prospectively evaluate and compare prognostic factors for improved surveillance and management.

Impact of nondiameter aortic indices on surgical eligibility: Results from the Treatment in Thoracic Aortic Aneurysm: Surgery Versus Surveillance (TITAN: SvS) randomized controlled trial.

OBJECTIVES: Traditional criterion for intervention on an asymptomatic ascending aortic aneurysm has been a maximal aortic diameter of 5.5 cm or more. The 2022 American College of Cardiology/American Heart Association aortic guidelines adopted cross-sectional aortic area/height ratio, aortic size index, and aortic height index as alternate parameters for surgical intervention. The objective of this study was to evaluate the impact of using these newer indices on patient eligibility for surgical intervention in a prospective, multicenter cohort with moderate-sized ascending aortic aneurysms between 5.0 and 5.4 cm. METHODS: Patients enrolled from 2018 to 2023 in the randomization or registry arms of the multicenter trial, Treatment In Thoracic Aortic aNeurysm: Surgery versus Surveillance, were included in the study. Clinical data were captured prospectively in an online database. Imaging data were derived from a core computed laboratory. RESULTS: Among the 329 included patients, 20% were female. Mean age was 65.0 ± 11.6 years, and mean maximal aortic diameter was 50.8 ± 3.9 mm. In the one-third of all patients (n = 109) who met any 1 of the 3 criteria (ie, aortic size index ≥3.08 cm/m2, aortic height index ≥3.21 cm/m, or cross-sectional aortic area/height ≥ 10 cm2/m), their mean maximal aortic diameter was 52.5 ± 0.52 mm. Alternate criteria were most commonly met in women compared with men: 20% versus 2% for aortic size index (P < .001), 39% versus 5% for aortic height index (P < .001), and 39% versus 21% for cross-sectional aortic area/height (P = .002), respectively. CONCLUSIONS: One-third of patients in Treatment In Thoracic Aortic aNeurysm: Surgery versus Surveillance would meet criteria for surgical intervention based on novel parameters versus the classic definition of diameter 5.5 cm or more. Surgical thresholds for aortic size index, aortic height index, or cross-sectional aortic area/height ratio are more likely to be met in female patients compared with male patients.

Hemiarch versus extended arch repair for acute type A dissection: Results from a multicenter national registry.

OBJECTIVE: We compared perioperative outcomes of patients with acute type A aortic dissection undergoing hemiarch (HA) versus extended arch (EA) repair with or without descending aortic intervention. METHODS: Nine hundred twenty-nine patients underwent acute type A aortic dissection repair (2002-2021, 9 centers) including open distal repair (HA) with or without additional EA repair. EA with intervention on the descending aorta (EAD) included elephant trunk, antegrade thoracic endovascular aortic replacement, or uncovered dissection stent. EA with no descending intervention (EAND), included unstented suture-only methods. Primary outcomes were in-hospital mortality, permanent neurologic deficit, computed tomography malperfusion resolution, and a composite. Multivariable logistic regression was also performed. RESULTS: Mean age was 66 ± 18 years, 30% (278 out of 929) were women, and HA was performed more frequently (75% [n = 695]) than EA (25% [n = 234]). EAD techniques included: dissection stent (39 out of 234 [17%]), thoracic endovascular aortic replacement (18 out of 234 [7.7%]), and elephant trunk (87 out of 234 [37%]). In-hospital mortality (EA: n = 49 [21%] and HA: n = 129 [19%]; P = .42), and neurological deficit (EA: n = 43 [18%] and HA: n = 121 [17%]; P = .74) were similar. EA was not independently associated with death (EA vs HA odds ratio, 1.09; 95% CI, 0.77-1.54; P = .63) or neurologic deficit (EA vs HA odds ratio, 0.85; 95% CI, 0.47-1.55; P = .59). Composite adverse events differed significantly (EA vs HA odds ratio, 1.47; 95% CI, 1.16-1.87; P = .001). Malperfusion resolved more frequently after EAD (EAD: n = 32 [80%], EAND: n = 18 [56%], HA: n = 71 [50%]; P = .004), although multivariable analysis was not significant (EAD vs HA odds ratio, 2.17; 95% CI, 0.83-5.66; P = .10). CONCLUSIONS: Extended arch interventions pose similar perioperative mortality and neurologic risks as Hemiarch. Descending aortic reinforcement may promote malperfusion restoration. Extended techniques should be approached with caution in acute dissection due to increased risk of adverse events.

Arterial Age and Early Vascular Aging, But Not Chronological Age, Are Associated With Faster Thoracic Aortic Aneurysm Growth.

Background Aneurysm size is an imperfect risk assessment tool for those with thoracic aortic aneurysm (TAA). Assessing arterial age may help TAA risk stratification, as it better reflects aortic health. We sought to evaluate arterial age as a predictor of faster TAA growth, independently of chronological age. Methods and Results We examined 137 patients with TAA. Arterial age was estimated according to validated equations, using patients' blood pressure and carotid-femoral pulse wave velocity. Aneurysm growth was determined prospectively from available imaging studies. Multivariable linear regression assessed the association of chronological age and arterial age with TAA growth, and multivariable logistic regression assessed associations of chronological and arterial age with the presence of accelerated aneurysm growth (defined as growth>median in the sample). Mean±SD chronological and arterial ages were 62.2±11.3 and 54.2±24.5 years, respectively. Mean baseline TAA size and follow-up time were 45.9±4.0 mm and 4.5±1.9 years, respectively. Median (interquartile range) TAA growth was 0.31 (0.14-0.52) mm/year. Older arterial age (ß±SE for 1 year: 0.004±0.001, P<0.0001) was independently associated with faster TAA growth, while chronological age was not (P=0.083). In logistic regression, each 5-year increase in arterial age was associated with a 23% increase in the odds of accelerated TAA growth (95% CI, 1.085-1.394; P=0.001). Conclusions Arterial age is independently associated with accelerated aneurysm expansion, while chronological age is not. Our results highlight that a noninvasive and inexpensive assessment of arterial age can potentially be useful for TAA risk stratification and disease monitoring as compared with the current clinical standard (chronological age).

Knowledge, attitudes, and practice preferences in the surgical threshold for ascending aortic aneurysm among Canadian cardiac surgeons.

OBJECTIVE: The survey aimed to assess the practice patterns of Canadian cardiac surgeons on the size threshold at which patients with ascending aortic aneurysm would be offered surgery. METHODS: A 18-question electronic survey was electronically distributed to 148 practicing cardiac surgeons in Canada via email from January to August 2020. Questions presented clinical scenarios focusing on modifying a single variable, and respondents were asked to identify their surgical size threshold for each of the clinical scenarios. RESULTS: The individual response rate was 62.0% (91/148) and institutional response rate was 89.3% (25/29). For an incidental asymptomatic ascending aortic aneurysm in a 60-year-old otherwise-healthy male patient with a tricuspid aortic valve and bicuspid aortic valve of 1.9 m2, 20.2% of the respondents would recommend surgery when the aneurysm was <5.5 cm. A significant number of surgeons modified their surgical threshold in response to changes to BSA, bicuspid aortic valve, growth rate, age, occupation, symptom, and family history (P < .01). Notably, if the patient had a bicuspid aortic valve, 41.0% of respondents lowered their threshold for surgery, with only 43.0% recommending surgery at ≥5.5 cm (P < .01). CONCLUSIONS: Practice variations exist in the current size threshold for surgery of ascending aortic aneurysms in Canada. These differences between surgeons are further accentuated in the context of bicuspid aortic valve, smaller body stature, younger age, low growth rate, family history, and for the performance of isometric exercise. These represent important areas where future prospective studies are required to inform best practice.

Combining Aortic Size With Arterial Hemodynamics Enhances Assessment of Future Thoracic Aortic Aneurysm Expansion.

BACKGROUND: Thoracic aortic aneurysm (TAA) is a deadly disease whose current method for risk stratification (aneurysm size) is imperfect. We sought to evaluate whether combining aortic size with hemodynamic measures that reflect the aorta's function was superior to aortic size alone in the assessment of TAA expansion. METHODS: One hundred thirty-seven nonoperated participants with TAA were followed prospectively. Aortic stiffness and pulsatile hemodynamics were noninvasively assessed at baseline with a combination of arterial tonometry with echocardiography using validated methodology. Aneurysm growth was calculated from standard imaging modalities. Multivariable linear regression models adjusted for potential confounders evaluated the association of aneurysm size and arterial hemodynamics, alone and in combination, with TAA growth. RESULTS: Sixty-nine percent of participants were male. Mean ± SD age, baseline aneurysm size, follow-up, and aneurysm expansion were, respectively, 62.2 ± 11.4 years, 45.9 ± 4.0 mm, 4.5 ± 1.9 years, and 0.41 ± 0.46 mm/year. In the linear regression models, the standardised ß (ß∗) for the association of aneurysm size with aneurysm expansion was 0.178 (P = 0.044). This was improved by combining aortic size with most measures of aortic function, with ß∗ ranging from 0.192 (for aneurysm size combined with central diastolic blood pressure) to 0.484 (for aneurysm size combined with carotid-femoral pulse-wave velocity) (P ≤ 0.05 for each). CONCLUSIONS: Combining aneurysm size with measures of arterial function improves assessment of aneurysm growth over TAA size alone, which is the standard for clinical decisions in TAA. Thus, combining aneurysm size with measures of aortic function provides a clinical advantage in the assessment of TAA disease activity.

In-hospital thromboembolic complications after frozen elephant trunk aortic arch repair.

OBJECTIVE: This study evaluated the frequency and clinical impact of thromboembolic complications after frozen elephant trunk aortic arch repair using the Thoraflex device (Terumo Aortic). METHODS: A total of 128 consecutive patients (mean age 67.9 ± 13.7 years, 31.0% female) underwent frozen elephant trunk aortic arch repair using the Thoraflex device between September 2014 and May 2021 in 4 Canadian centers. Patient baseline characteristics, intraoperative details, and frozen elephant trunk thromboembolic complications were collected retrospectively and analyzed. RESULTS: Fifteen patients (11.7%) had thrombus visualized within the frozen elephant trunk stent graft on imaging (n = 8; 53.3%) or had a thromboembolic event (n = 9; 60.0%) before hospital discharge. Sites of embolism were mesenteric (n = 8; 88.9%), renal (n = 4; 44.4%), and iliofemoral (n = 1; 11.1%). Patients who experienced thromboembolic complications were more likely to have a history of autoimmune disease (n = 3; 20.0% vs n = 2; 1.8%; P = .01) and implantation of a longer frozen elephant trunk stent graft (150 mm vs 100 mm) (n = 13; 86.7% vs n = 45; 39.8%; P < .001). All patients with thromboembolic complications received therapeutic anticoagulation, and a smaller proportion required an open surgical (n = 5; 33.3%) or an endovascular (n = 2; 13.3%) intervention. Radiographic resolution of thromboembolic complications was observed in 86.7% of patients (n = 13). In-hospital mortality occurred in 1 patient, stroke occurred in 1 patient, and transient spinal cord injury occurred in 1 patient. CONCLUSIONS: Thromboembolic complications occur more often than previously recognized after frozen elephant trunk aortic arch repair using the Thoraflex device and are associated with increased rates of surgical and endovascular reintervention. Prevention and management of these complications require further study.

Estimated Aortic Pulse Wave Velocity Is Associated With Faster Thoracic Aortic Aneurysm Growth: A Prospective Cohort Study With Sex-Specific Analyses.

BACKGROUND: Thoracic aortic aneurysm (TAA) is associated with high morbidity and mortality, and there is a critical need for improved tools for risk assessment and prognostication. We have previously shown that aortic stiffness, measured from arterial tonometry (carotid-femoral pulse wave velocity [cfPWV]), is independently associated with TAA expansion. To increase clinical applicability, we sought to determine the association of mathematically estimated aortic pulse wave velocity (e-PWV) with TAA expansion. METHODS: One-hundred and five consecutive unoperated subjects with TAA were recruited. We used arterial tonometry to measure cfPWV and used mean arterial pressure and age to calculate e-PWV according to validated equations. Multivariable linear regression assessed associations of baseline e-PWV with future aneurysm growth. Given sex differences in TAA outcomes, sex-stratified analyses were performed. RESULTS: Seventy-eight percent of subjects were men. Mean ± standard deviation (SD) age, baseline aneurysm size, and follow-up time were 62.6 ± 11.4 years, 46.2 ± 3.8 mm, and 2.9 ± 1.0 years, respectively. Aneurysm growth was 0.43 ± 0.37 mm per year; e-PWV was independently associated with future aneurysm expansion (ß ± SE: 0.240 ± 0.085, P = 0.006). In sex-specific analyses, e-PWV was associated with aneurysm growth in both men (ß ± standard error (SE) : 0.076 ± 0.022, P = 0.001) and women (ß ± SE : 0.145 ± 0.050, P = 0.012), but the strength of association nearly twice as strong in women as in men. CONCLUSIONS: Greater aortic stiffness reflects worse aortic health and provides novel insights into disease activity; e-PWV is independently associated with TAA growth. This finding increases clinical applicability, as e-PWV can be estimated simply, quickly, and free of cost without the need for specialized equipment.

Risk score for arch reconstruction under circulatory arrest with hypothermia: The ARCH score.

OBJECTIVE: Currently, there is no risk scores built to predict risk in thoracic aortic surgery. This study aims to develop and internally validate a risk prediction score for patients who require arch reconstruction with hypothermic circulatory arrest. METHODS: From 2002 to 2018, data for 2270 patients who underwent aortic arch surgery in 12 institutions in Canada were retrospectively collected. The outcomes modeled included in-hospital mortality and a modified Society of Thoracic Surgeons-defined composite for mortality or major morbidity. Multivariable logistic regression using least absolute shrinkage and selection operator selection method and mixed-effect regression model was used to select the predictors. Internal calibration of the final models is presented with an observed-versus-predicted plot. RESULTS: There were 182 in-hospital deaths (8.0%), and the incidence of Society of Thoracic Surgeons-defined composite for mortality or major morbidity was 27.9%. Variables that increased risk of mortality are age, chronic obstructive pulmonary disease, atrial fibrillation, peripheral vascular disease, New York Heart Association class ≥III symptoms, acute aortic dissection or rupture, use of elephant trunk, concomitant surgery, and increased cardiopulmonary bypass time, with median c-statistics of 0.85 on internal validation. The c-statistics was 0.77 for the model predicting Society of Thoracic Surgeons-defined composite. Internal assessment shows good overall calibration for both models. CONCLUSIONS: We developed and internally validated a risk score for patients undergoing arch surgery requiring hypothermic circulatory arrest using a multicenter database. Once externally validated, the ARCH (Arch Reconstruction under Circulatory arrest with Hypothermia) score would allow for better patient risk-stratification and aid in the decision-making process for surgeons and patient prior to surgery.