Long-term outcomes of aortic root procedures for heterogenous ascending aneurysm disease in bicuspid aortic valve syndrome.

OBJECTIVE: Surgery for ascending aneurysms in bicuspid aortic valve syndrome primarily includes Bentall root replacement, aortic valve replacement with supracoronary ascending aorta replacement (AVRSCAAR), and valve-sparing root reimplantation (VSRR). Comparative analysis of long-term clinical and functional outcomes of these procedures is detailed. METHODS: From 1997 to 2017, 635 patients with bicuspid aortic valve undergoing root complex-focused procedures electively were stratified by valvulopathy (ie, aortic stenosis vs aortic insufficiency) and substratified into ascending or root aneurysm phenotype. Inverse probability weights were calculated to adjust for baseline differences. RESULTS: Kaplan-Meier curves for all-cause mortality demonstrated no difference between Bentall versus AVRSCAAR for aortic stenosis and aortic insufficiency presentations (log-rank P > .05). In patients with aortic stenosis, multivariable Cox regression showed significantly decreased risk of stroke for biologic AVRSCAAR (hazard ratio, 0.04; P = .013). Aortic reoperation rates were similar for biologic versus mechanical valves (P = .353). In patients with aortic insufficiency, similar long-term mortality (hazard ratio, 0.95; P = .93), but lower stroke risk in biologic AVRSCAAR group by Cox regression, and lower aortic reoperation rate was noted (coefficient < 0.01; P < .001). Comparing Bentall to VSRR, mortality (hazard ratio, 0.12; P = .022) was significantly improved in patients undergoing VSRR, but recurrence of moderate or greater aortic insufficiency was higher in VSRR by multistate model (beta coefficient 2.63; P < .001). CONCLUSIONS: A tailored approach to heterogeneous ascending aneurysm pathologies in bicuspid aortic valve syndrome utilizing Bentall, AVRSCAAR, and VSRR procedures renders excellent long-term clinical and functional outcomes, with biologic conduits showing equivalent to improved clinical outcomes.

Midterm outcomes and durability of sinus segment preservation compared with root replacement for acute type A aortic dissection.

OBJECTIVE: The durability of root repair for acute type A aortic dissection is not well studied in the context of aortic insufficiency and stability of the sinuses of Valsalva. We compared clinical and functional outcomes in patients undergoing root repair and replacement for acute type A aortic dissection. METHODS: Of 716 patients undergoing surgery for acute type A aortic dissection, 585 (81.7%) underwent root repair and 131 (18.3%) underwent root replacement. Survival, cumulative incidence of reoperation, aortic insufficiency, and sinuses of Valsalva dilation were compared between the 2 groups. RESULTS: Survival at 1, 5, and 10 years was 84.1% versus 77.3%, 70.8% versus 69.2%, 57.6% versus 58.0% in the root repair and replacement groups, respectively (P = .69). Cumulative incidence of reoperation at 1, 5, and 10 years was 0.0% versus 0.8%, 1.4% versus 3.8%, and 3.4% versus 8.6% in the root repair and root replacement groups, respectively (P = .011). Multivariable Cox regression identified sinuses of Valsalva diameter 45 mm or more as a risk factor for proximal aortic reoperation (hazard ratio, 9.06; 95% confidence interval, 1.26-65.24). In a repeated-measures, linear, mixed-effects model, root replacement was associated with smaller follow-up of sinuses of Valsalva dimensions (ß = -0.66, P < .001). In an ordinal longitudinal mixed model, root replacement was associated with lower severity of postoperative aortic insufficiency (ß = -3.10, P < .001). CONCLUSIONS: Survival is similar, but the incidence of aortic insufficiency and root dilation may be greater after root repair compared with root replacement for acute type A aortic dissection.

Midterm outcomes of emergency surgery for acute type A aortic dissection in octogenarians.

OBJECTIVE: The incidence of elderly patients with acute type A aortic dissection is increasing. A recent analysis of the International Registry of Acute Aortic Dissection failed to show a mortality benefit with surgery compared with medical management in octogenarians. Therefore, we compared our institutional outcomes of emergency surgery for acute type A aortic dissection in octogenarians versus septuagenarians to understand the outcomes of surgical intervention in elderly patients. METHODS: From 2002 to 2017, 70 octogenarians (aged ≥80 years) and 165 septuagenarians (70-79 years) underwent surgery for acute type A aortic dissection (N = 235, total). Quality of life was assessed by the RAND Short Form-36 quality of life survey. Midterm clinical and functional data were obtained retrospectively. RESULTS: At baseline, septuagenarians had a higher prevalence of diabetes (20.6% vs 5.7%, P = .01). The prevalence of cardiopulmonary resuscitation was 4.8% versus 10.0% (P = .24) in septuagenarians and octogenarians. The prevalence of cardiogenic shock was 18.2% versus 27.1% (P = .17). Thirty-day/in-hospital mortality was 21.2% versus 28.6% (P = .29). Multivariable logistic regression identified cardiogenic shock as an independent risk factor for in-hospital mortality (odds ratio, 10.07; 95% confidence interval, 2.30-44.03) in octogenarians. Survival at 5 years was 49.7% (42.1%-58.6%) versus 34.2% (23.9%-48.8%) in septuagenarians and octogenarians, respectively. Responses to the quality of life survey were no different between septuagenarians and octogenarians across all 8 quality of life categories. CONCLUSIONS: Clinical outcomes after surgery for acute type A aortic dissection are similar in octogenarians and septuagenarians. For discharged survivors, quality of life remains favorable and does not differ between the 2 groups.

Recurrent aortic insufficiency after emergency surgery for acute type A aortic dissection with aortic root preservation.

OBJECTIVE: Patients with acute type A aortic dissection demonstrate a wide range of aortic insufficiency. Outcomes after valve resuspension and root repair are not well studied in the long term. We evaluated the long-term effects of preoperative aortic insufficiency in patients undergoing emergency root-preserving surgery for acute type A aortic dissection. METHODS: From 2002 to 2017, 558 of 776 patients with acute type A aortic dissection underwent native aortic valve resuspension and root reconstruction. Patients were stratified into 4 groups by preoperative aortic insufficiency grade (n = 539): aortic insufficiency less than 2+ (n = 348), aortic insufficiency = 2+ (n = 72), aortic insufficiency = 3+ (n = 49), and aortic insufficiency = 4+ (n = 70). Multivariable ordinal longitudinal mixed effects and multi-state transition models were used to assess risk factors for recurrent aortic insufficiency. RESULTS: The prevalence of cardiogenic shock in patients presenting with preoperative aortic insufficiency less than 2+, 2+, 3+, and 4+ was 53 of 348 (15.2%), 12 of 72 (16.7%), 10 of 49 (20.4%), and 24 of 70 (34.3%), respectively (P = .002). Postoperatively, 94.0% of patients had aortic insufficiency 1+ or less at discharge. Operative mortality was 34 of 348 (9.8%), 10 of 72 (13.9%), 6 of 49 (12.2%), and 12 of 70 (17.1%) (P = .303). In an ordinal mixed effects model, preoperative aortic insufficiency was associated with more severe postoperative aortic insufficiency. The multi-state transition model demonstrated that severe aortic insufficiency was associated with progression from no to mild aortic insufficiency (hazard ratio, 2.14; 95% confidence interval, 1.35-3.38), and progression from mild to moderate aortic insufficiency (hazard ratio, 5.70; 95% confidence interval, 1.88-17.30). CONCLUSIONS: Preoperative aortic insufficiency is an important predictor of recurrent aortic insufficiency in patients undergoing valve resuspension with root reconstruction for emergency acute type A aortic dissection repair. Increased echocardiographic surveillance for recurrent aortic insufficiency may be warranted in this cohort.

Two different geometric orientations for aortic neoroot creation in bicuspid aortic valve repair with root reimplantation.

OBJECTIVE: Bicuspid aortic valve (BAV) represents 2 cusps oriented along a spectrum of equal (180°/180°) or unequal (150°/210°) leaflet surface area distribution along the aortic annular plane. We have taken the approach of respecting the native geometric orientation of the repaired BAV leaflets when creating the aortic neoroot during valve-sparing root reimplantation (VSRR) procedures. We investigated midterm outcomes with this 2-prong approach for VSRR in BAV syndrome. METHODS: Of 72 patients in a prospectively maintained BAV repair database, 68 met inclusion criteria: 36 patients had 180°/180° neoroot geometry, and 32 patients had 150°/210° orientation. A multivariate ordinal logistic mixed effects model was performed to study parameters associated with recurrent AI greater than 2+. RESULTS: Preoperative parameters were similar between 180°/180° and 150°/210° groups, except for greater incidence of AI 4+ in the latter (50.0% [n = 16] vs 8.3% [n = 3]; P < .001). Postoperatively, stroke, renal failure, reoperation for bleeding, and pacemaker rates were 0 in the entire cohort. In-hospital/30-day mortality in the entire cohort was 1.5% (n = 1). Multivariate ordinal logistic mixed effects model showed that preoperative AI greater than 3+ (odds ratio, 0.4; P = .46) and geometric orientation of the aortic neoroot (odds ratio, 3.8; P = .25) were not significantly associated with recurrence of AI greater than 2+. CONCLUSIONS: Respecting BAV geometry for VSRR neoroot creation yields excellent midterm outcomes and may minimize conjoint cusp leaflet stress that may occur in "forcing" a 150°/210° type I BAV into a 180°/180° neoroot.

Selection of prosthetic aortic valve and root replacement in patients younger than age 30 years.

OBJECTIVE: Long-term outcomes of prosthetic aortic valve/root replacement in patients aged 30 years or younger are not well understood. We report our single institutional experience in this young cohort. METHODS: From 1998 to 2016, 99 patients (age range, 16-30 years) underwent aortic valve replacement (n = 57), aortic valve replacement and supracoronary ascending aorta replacement (n = 6), or aortic root replacement (n = 36). A prospectively maintained aortic valve database was retrospectively reviewed to complete longitudinal functional and clinical data. Total follow-up was 493 patient years. RESULTS: Surgical indications included primary stenosis/insufficiency (52% [n = 51]), Marfan syndrome (10% [n = 10]), and endocarditis (33.3% [n = 33]). Fifty-eight patients (59%) underwent mechanical valve replacement, with 41 patients (41%) receiving a biologic/bioprosthetic valve. Twenty-five patients underwent aortic valve reoperation after index procedure with following indications: prosthesis-patient mismatch 1.0% (n = 1), prosthetic valve degeneration/dysfunction 10% (n = 10), connective tissue 2% (n = 2), and endocarditis 12% (n = 12). Mortality (30-day/in-hospital) and stroke rate were 3.0% (n = 3) and 1% (n = 1), respectively. One-, 5-, and 10-year actuarial freedom from aortic valve reoperation by valve type was 89.1%, 84.6%, and 69.4% for the Mechanical Valve group and 89.6%, 70.9%, and 57.6% for the Biologic/Bioprosthetic Valve group, respectively (log rank P = .279). Replacement valve size ≤21 mm was a significant risk factor for reoperation, and was associated with progression of mean aortic valve transvalvular gradients over follow-up. Valve type had no effect. CONCLUSIONS: The choice of mechanical versus biologic/bioprosthetic valve does not affect freedom from reoperation or survival rates in this young cohort during mid- to long-term follow-up. Smaller aortic valve replacement size (≤21 mm) is a significant risk factor for reoperation and progression of mean aortic valve gradients.

Aortic Regurgitation in Acute Type-A Aortic Dissection: A Clinical Classification for the Perioperative Echocardiographer in the Era of the Functional Aortic Annulus.

The functional aortic annulus offers a clinical approach for the perioperative echocardiographer to classify the mechanisms of aortic regurgitation in acute type-A dissection. Comprehensive examination of the functional aortic annulus in this setting using transesophageal echocardiography can guide surgical therapy for the aortic root by considering the following important aspects: severity and mechanism of aortic regurgitation, extent of root dissection, and the pattern of coronary artery involvement. The final choice of surgical therapy also should take into account factors, such as patient presentation and surgical experience, to limit mortality and morbidity from this challenging acute aortic syndrome. This review explores these concepts in detail within the framework of the functional aortic annulus, detailed anatomic considerations, and the latest literature.

Impact of acute postoperative limb ischemia after cardiac and thoracic aortic surgery.

OBJECTIVE: Acute limb ischemia (ALI) is the cause of significant morbidity and mortality. Although ALI after cardiac surgery is associated with high rates of morbidity and mortality, there are no robust, controlled analyses of the risk factors and outcomes of ALI in this setting. We aimed to identify risk factors for and to delineate outcomes after ALI in patients undergoing cardiac surgery. METHODS: We performed a retrospective review of prospectively collected data on patients undergoing cardiac surgery at our institution between 2002 and 2012. RESULTS: Between 2002 and 2012, there were 11,343 patients who underwent major open cardiac surgery, with 156 cases of ALI for an incidence of 1.4%. In a multivariable model, significant risk factors for ALI included body surface area (odds ratio [OR], 0.41; 95% confidence interval [CI], 0.18-0.92), current smoking status (OR, 2.2; 95% CI, 1.3-3.7), peripheral arterial disease (OR, 2.5; 95% CI, 1.6-3.7), nonelective operative status (OR, 1.9-5.0; 95% CI, 1.2-19.7), use of extracorporeal membrane oxygenation (OR, 5.6; 95% CI, 2.5-11.6) or intra-aortic balloon pump (OR, 4.7; 95% CI, 2.9-7.5), and valve operation (OR, 2.1; 95% CI, 1.1-4.0). There were 105 (67%) patients who developed ALI who required an operation, and 27 (17%) required an amputation on the index admission. ALI was associated with a significant reduction in long-term survival (hazard ratio, 3.72; 95% CI, 2.97-4.65; P < .0001). CONCLUSIONS: ALI is associated with significant morbidity and mortality, and it is also associated with reduced long-term survival. Those patients with the risk factors described require extra vigilance to limit the risk of ALI and should be managed in accordance with the patient's overall clinical condition and goals of care.

Outcomes, readmissions, and costs in transfemoral and alterative access transcatheter aortic valve replacement in the US Medicare population.

OBJECTIVE: To comprehensively evaluate and compare utilization, outcomes, and especially costs of transfemoral (TF), transapical (TA), and transaortic (TAO) transcatheter aortic valve replacement (TAVR). METHODS: All Medicare fee-for-service patients undergoing TF (n = 4065), TA (n = 691), or TAO (n = 274) TAVR between January 1, 2011, and November 30, 2012, were identified using Health Care Procedure Classification Codes present on Medicare claims. Hospital charges from Medicare claims were converted to costs using hospital-specific Medicare cost-to-charge ratios. RESULTS: TA and TAO patients were similar in age, race, and common comorbidities. Compared with TF patients, TA and TAO patients were more likely to be female and to have peripheral vascular disease, chronic lung disease, and renal failure. Thirty-day mortality rates were higher among TA and TAO patients than among TF patients (TA, 9.6%; TAO, 8.0%; TF, 5.0%; P < .001). Adjusted mortality beyond 1 year did not differ by access. TA patients were more likely to require cardiopulmonary bypass (CPB). Increased adjusted mortality was associated with CPB (hazard ratio, 2.13; P < .01) and increased 30-day cost ($62,000 [interquartile range (IQR)], $45,100-$86,400 versus $48,800 [IQR, $38,100-$62,900]; P < .01). Cost at 30 days was lowest for TF ($48,600) compared with TA ($49,800; P < .01) and TAO ($53,200; P = .03). CONCLUSIONS: For patients ineligible to receive TF TAVR, TAO and TA approaches offer similar clinical outcomes at similar cost with acceptable operative and 1-year survival, except for higher rates of CPB use in TA patients. CPB was associated with worse survival and increased costs.

Fate of remnant sinuses of Valsalva in patients with bicuspid and trileaflet valves undergoing aortic valve, ascending aorta, and aortic arch replacement.

OBJECTIVE: In patients presenting with aortic valvulopathy with concomitant ascending aortic aneurysm, surgical management of the sinus of Valsalva segment remains undefined, especially for moderately dilated aortic roots. In patients with this pathology undergoing aortic valve replacement with supracoronary ascending aorta replacement, we assessed the fate of the remnant preserved sinus of Valsalva segment stratified by aortic valve morphology and pathology. METHODS: From 2002 to 2015, 428 patients underwent elective aortic valve replacement with supracoronary ascending aorta replacement. Patients were stratified on the basis of valvular morphology (bicuspid aortic valve [n = 254] and tricuspid aortic valve [n = 174]), valvular pathology (bicuspid aortic valve with aortic stenosis [n = 178], bicuspid aortic valve with aortic insufficiency [n = 76], tricuspid aortic valve with aortic stenosis [n = 61], tricuspid aortic valve with aortic insufficiency [n = 113]), and preoperative sinus of Valsalva dimensions (<40, 40-45, >45 mm). RESULTS: Kaplan-Meier analysis revealed no significant difference in freedom from reoperation in tricuspid aortic valve versus bicuspid aortic valve (P = .576). Multivariable Cox regression model performed with sinus of Valsalva dimensions at baseline and follow-up as time-varying covariates did not adversely affect survival. A repeated-measure, mixed-effects model constructed to assess longitudinal sinus of Valsalva trends revealed that the retained sinus of Valsalva dimensions remain stable over long-term follow-up (discharge to ≥10 years), irrespective of valvular morphology/pathology (bicuspid aortic valve with aortic insufficiency, tricuspid aortic valve with aortic insufficiency, tricuspid aortic valve with aortic stenosis) and preoperative sinus of Valsalva groups (<40, 40-45, >45 mm). CONCLUSIONS: In patients with nonaneurysmal sinuses of Valsalva undergoing aortic valve replacement with supracoronary ascending aorta replacement, the sinus segment can be preserved irrespective of the type of valvular pathology (aortic stenosis vs aortic insufficiency) or valvular morphology (bicuspid aortic valve vs tricuspid aortic valve). Aortic valve replacement with supracoronary ascending aorta replacement may have a stabilizing effect on the sinus segment over long-term follow-up in patients with tricuspid aortic valves or bicuspid aortic valves.

Calcification and Oxidative Modifications Are Associated With Progressive Bioprosthetic Heart Valve Dysfunction.

BACKGROUND: Bioprosthetic heart valves (BHVs), fabricated from glutaraldehyde-pretreated bovine pericardium or porcine aortic valves, are widely used for the surgical or interventional treatment of heart valve disease. Reoperation becomes increasingly necessary over time because of BHV dysfunction. METHODS AND RESULTS: Forty-seven explanted BHV aortic valve replacements were retrieved at reoperation for clinically severe BHV dysfunction over the period 2010-2016. Clinical explant analyses of BHV leaflets for calcium (atomic absorption spectroscopy) and oxidized amino acids, per mass spectroscopy, were primary end points. Comorbidities for earlier BHV explant included diabetes mellitus and coronary artery bypass grafting. Mean calcium levels in BHV leaflets were significantly increased compared with unimplanted BHV (P<0.001); however, time to reoperation did not differ comparing calcified and noncalcified BHV. BHV dityrosine, an oxidized amino acid cross-link, was significantly increased in the explants (227.55±33.27 µmol/mol [dityrosine/tyrosine]) but was undetectable in unimplanted leaflets (P<0.001). BHV regional analyses revealed that dityrosine, ranging from 57.5 to 227.8 µmol/mol (dityrosine/tyrosine), was detectable only in the midleaflet samples, indicating the site-specific nature of dityrosine formation. 3-Chlorotyrosine, an oxidized amino acid formed by myeloperoxidase-catalyzed chlorinating oxidants, correlated with BHV calcium content in leaflet explant analyses from coronary artery bypass graft patients (r=0.62, P=0.01) but was not significantly correlated with calcification in non-coronary artery bypass graft explanted BHV. CONCLUSIONS: Both increased BHV leaflet calcium levels and elevated oxidized amino acids were associated with bioprosthesis dysfunction necessitating reoperation; however, BHV calcium levels were not a determinant of implant duration, indicating a potentially important role for oxidized amino acid formation in BHV dysfunction.

Direct innominate artery cannulation: An alternate technique for antegrade cerebral perfusion during aortic hemiarch reconstruction.

OBJECTIVE: We describe an alternate technique for establishing antegrade cerebral perfusion (ACP) during hypothermic circulatory arrest via direct, central cannulation of the innominate artery. METHODS: From 2009 to 2015, 100 elective hemiarch reconstructions for proximal aortic aneurysms were performed under moderate hypothermic circulatory arrest (MHCA). Cerebral perfusion was instituted with ACP via direct cannulation of the innominate artery. RESULTS: Mean patient age was 63 ± 13 years (72 men; 72%). Mean MHCA temperature was 27.3°C ± 1.0°C (median, 28°C). Mean ACP time was 17 ± 4 minutes and mean crossclamp time was 134 ± 42 minutes. Proximal reconstruction included root replacement with composite valved graft (n = 47), valve sparing root reimplantation (n = 16), and aortic valve replacement (n = 19). In-hospital 30-day mortality (n = 1; 1%), stroke (1; 1%), reversible ischemic neurologic deficit (n = 1; 1%), coma (n = 0), and renal failure (n = 1; 1%) rates were low. There was no incidence of injury or dissection of the innominate artery. CONCLUSIONS: Direct, central innominate artery cannulation for ACP yields excellent outcomes. This technique is safe, provides excellent cerebral protection during circulatory arrest and simplifies the circulatory management strategy for elective ascending aortic and hemiarch reconstruction.

Appropriate patient selection or health care rationing? Lessons from surgical aortic valve replacement in the Placement of Aortic Transcatheter Valves I trial.

OBJECTIVES: The study objectives were to (1) compare the safety of high-risk surgical aortic valve replacement in the Placement of Aortic Transcatheter Valves (PARTNER) I trial with Society of Thoracic Surgeons national benchmarks; (2) reference intermediate-term survival to that of the US population; and (3) identify subsets of patients for whom aortic valve replacement may be futile, with no survival benefit compared with therapy without aortic valve replacement. METHODS: From May 2007 to October 2009, 699 patients with high surgical risk, aged 84 ± 6.3 years, were randomized in PARTNER-IA; 313 patients underwent surgical aortic valve replacement. Median follow-up was 2.8 years. Survival for therapy without aortic valve replacement used 181 PARTNER-IB patients. RESULTS: Operative mortality was 10.5% (expected 9.3%), stroke 2.6% (expected 3.5%), renal failure 5.8% (expected 12%), sternal wound infection 0.64% (expected 0.33%), and prolonged length of stay 26% (expected 18%). However, calibration of observed events in this relatively small sample was poor. Survival at 1, 2, 3, and 4 years was 75%, 68%, 57%, and 44%, respectively, lower than 90%, 81%, 73%, and 65%, respectively, in the US population, but higher than 53%, 32%, 21%, and 14%, respectively, in patients without aortic valve replacement. Risk factors for death included smaller body mass index, lower albumin, history of cancer, and prosthesis-patient mismatch. Within this high-risk aortic valve replacement group, only the 8% of patients with the poorest risk profiles had estimated 1-year survival less than that of similar patients treated without aortic valve replacement. CONCLUSIONS: PARTNER selection criteria for surgical aortic valve replacement, with a few caveats, may be more appropriate, realistic indications for surgery than those of the past, reflecting contemporary surgical management of severe aortic stenosis in high-risk patients at experienced sites.

Use of computational fluid dynamics studies in predicting aneurysmal degeneration of acute type B aortic dissections.

OBJECTIVE: Whereas uncomplicated acute type B aortic dissections are often medically managed with good outcomes, a subset develop subacute or chronic aneurysmal dilation. We hypothesized that computational fluid dynamics (CFD) simulations may be useful in identifying patients at risk for this complication. METHODS: Patients with acute type B dissection complicated by rapidly expanding aortic aneurysms (N = 7) were compared with patients with stable aortic diameters (N = 7). Three-dimensional patient-specific dissection geometries were generated from computed tomography angiography and used in CFD simulations of pulsatile blood flow. Hemodynamic parameters including false lumen flow and wall shear stress were compared. RESULTS: Patients with rapid aneurysmal degeneration had a growth rate of 5.3 ± 2.7 mm/mo compared with those with stable aortic diameters, who had rates of 0.2 ± 0.02 mm/mo. Groups did not differ in initial aortic diameter (36.1 ± 2.9 vs 34.4 ± 3.6 mm; P = .122) or false lumen size (22.6 ± 2.9 vs 20.2 ± 4.5 mm; P = .224). In patients with rapidly expanding aneurysms, a greater percentage of total flow passed through the false lumen (78.3% ± 9.3% vs 56.3% ± 11.8%; P = .016). The time-averaged wall shear stress on the aortic wall was also significantly higher (12.6 ± 3.7 vs 7.4 ± 2.8 Pa; P = .028). CONCLUSIONS: Hemodynamic parameters derived from CFD simulations of acute type B aortic dissections were significantly different in dissections complicated by aneurysm formation. Thus, CFD may assist in predicting which patients may benefit from early stent grafting.

The functional aortic annulus in the 3D era: focus on transcatheter aortic valve replacement for the perioperative echocardiographer.

The functional aortic annulus represents a sound clinical framework for understanding the components of the aortic root complex. Recent three-dimensional imaging analysis has demonstrated that the aortic annulus frequently is elliptical rather than circular. Comprehensive three-dimensional quantification of this aortic annular geometry by transesophageal echocardiography and/or multidetector computed tomography is essential to guide precise prosthesis sizing in transcatheter aortic valve replacement to minimize paravalvular leak for optimal clinical outcome. Furthermore, three-dimensional transesophageal echocardiography accurately can quantify additional parameters of the functional aortic annulus such as coronary height for complete sizing profiles for all valve types in transcatheter aortic valve replacement. Although it is maturing rapidly as a clinical imaging modality, its role in transcatheter aortic valve replacement is seen best as complementary to multidetector computed tomography in a multidisciplinary heart team model.

Endovascular repair of the ascending aorta in patients at high risk for open repair.

OBJECTIVE: Although endovascular repair has been widely adopted for treatment of descending thoracic aortic pathologies, its role in ascending aortic pathologies remains undefined. We reviewed our experience with endovascular repair of ascending aortic pathologies in patients facing high or prohibitive risk with open surgical treatment. METHODS: From 2007 to 2013, 6 patients (aged 16-90 years) underwent endovascular repair (pseudoaneurysm, n = 4; acute type A aortic dissection, n = 2). Their records were retrospectively reviewed. RESULTS: All patients had extensive comorbidities or anatomic features making an open surgical approach high risk. Three cases were done on an emergency basis (aortic dissection, n = 2; ruptured pseudoaneurysm, n = 1). Ascending aortic access was obtained through transapical (n = 4), transfemoral (n = 1), and left common carotid artery (n = 1) approaches. Cook Zenith TX2 (n = 4), Cook EVAR iliac limb (n = 1), and Amplatzer occluder (n = 1) devices were used, with 3 patients requiring more than 1 stent-graft. Stent-graft lengths ranged from 55 to 81 mm; diameters ranged from 22 to 40 mm. Technical success was achieved in 5 cases (83%); 1 patient (type A dissection) had an intraoperative endoleak not amendable to further endovascular repair. In-hospital and 30-day mortalities were zero. One patient sustained a minor stroke, which reversed completely. Stay ranged from 5 to 15 days. On follow-up, 1 patient (type A dissection) had an endoleak at 12 months. Two patients died of nonaortic causes at 6 and 27 months after endovascular repair. CONCLUSIONS: Endovascular repair of ascending aortic pathology is feasible in patients facing high risk with open surgery, with promising early results. Technical challenges remain in adapting current endovascular technology to ascending aortic pathologies, particularly type A aortic dissection.

Validation of semiautomated and locally resolved aortic wall thickness measurements from computed tomography.

OBJECTIVE: Aortic wall thickness (AWT) is important for anatomic description and biomechanical modeling of aneurysmal disease. However, no validated, noninvasive method for measuring AWT exists. We hypothesized that semiautomated image segmentation algorithms applied to computed tomography angiography (CTA) can accurately measure AWT. METHODS: Aortic samples from 10 patients undergoing open thoracoabdominal aneurysm repair were taken from sites of the proximal or distal anastomosis, or both, yielding 13 samples. Aortic specimens were fixed in formalin, embedded in paraffin, and sectioned. After staining with hematoxylin and eosin and Masson's trichrome, sections were digitally scanned and measured. Patients' preoperative CTA Digital Imaging and Communications in Medicine (DICOM; National Electrical Manufacturers Association, Rosslyn, Va) images were segmented into luminal, inner arterial, and outer arterial surfaces with custom algorithms using active contours, isoline contour detection, and texture analysis. AWT values derived from image data were compared with measurements of corresponding pathologic specimens. RESULTS: AWT determined by CTA averaged 2.33 ± 0.66 mm (range, 1.52-3.55 mm), and the AWT of pathologic specimens averaged 2.36 ± 0.75 mm (range, 1.51-4.16 mm). The percentage difference between pathologic specimens and CTA-determined AWT was 9.5% ± 4.1% (range, 1.8%-16.7%). The correlation between image-based measurements and pathologic measurements was high (R = 0.935). The 95% limits of agreement computed by Bland-Altman analysis fell within the range of -0.42 and 0.42 mm. CONCLUSIONS: Semiautomated analysis of CTA images can be used to accurately measure regional and patient-specific AWT, as validated using pathologic ex vivo human aortic specimens. Descriptions and reconstructions of aortic aneurysms that incorporate locally resolved wall thickness are feasible and may improve future attempts at biomechanical analyses.

Impact of wall thickness and saccular geometry on the computational wall stress of descending thoracic aortic aneurysms.

BACKGROUND: Wall stress calculated using finite element analysis has been used to predict rupture risk of aortic aneurysms. Prior models often assume uniform aortic wall thickness and fusiform geometry. We examined the effects of including local wall thickness, intraluminal thrombus, calcifications, and saccular geometry on peak wall stress (PWS) in finite element analysis of descending thoracic aortic aneurysms. METHODS AND RESULTS: Computed tomographic angiography of descending thoracic aortic aneurysms (n=10 total, 5 fusiform and 5 saccular) underwent 3-dimensional reconstruction with custom algorithms. For each aneurysm, an initial model was constructed with uniform wall thickness. Experimental models explored the addition of variable wall thickness, calcifications, and intraluminal thrombus. Each model was loaded with 120 mm Hg pressure, and von Mises PWS was computed. The mean PWS of uniform wall thickness models was 410 ± 111 kPa. The imposition of variable wall thickness increased PWS (481 ± 126 kPa, P<0.001). Although the addition of calcifications was not statistically significant (506 ± 126 kPa, P=0.07), the addition of intraluminal thrombus to variable wall thickness (359 ± 86 kPa, P ≤ 0.001) reduced PWS. A final model incorporating all features also reduced PWS (368 ± 88 kPa, P<0.001). Saccular geometry did not increase diameter-normalized stress in the final model (77 ± 7 versus 67 ± 12 kPa/cm, P=0.22). CONCLUSIONS: Incorporation of local wall thickness can significantly increase PWS in finite element analysis models of thoracic aortic aneurysms. Incorporating variable wall thickness, intraluminal thrombus, and calcifications significantly impacts computed PWS of thoracic aneurysms; sophisticated models may, therefore, be more accurate in assessing rupture risk. Saccular aneurysms did not demonstrate a significantly higher normalized PWS than fusiform aneurysms.