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Division of Cardiothoracic and Vascular Surgery, New York Presbyterian Hospital, Columbia University Medical Center, New York, NYDepartment of Cardiovascular Surgery, Shonan-Kamakura General Hospital, Kamakura, Kanagawa, Japan
Address for reprints: Hiroo Takayama, MD, PhD, Division of Cardiothoracic and Vascular Surgery, New York Presbyterian Hospital, Columbia University Medical Center, 177 Fort Washington Ave, New York, NY 10032.
There are few data to delineate the risk differences among open aortic procedures. We aimed to investigate the influence of the procedural types on the outcomes of proximal thoracic aortic aneurysm repair.
Methods
Among 1900 patients who underwent aortic replacement in our institution between 2005 and 2019, 1132 patients with aortic aneurysm who underwent a graft replacement of proximal thoracic aorta were retrospectively reviewed. Patients were divided into 4 groups based on the extent of the aortic replacement: isolated ascending aortic replacement (n = 52); ascending aortic replacement with distal extension with hemiarch, partial arch, or total arch replacement (n = 126); ascending aortic replacement with proximal extension with aortic valve or root replacement (n = 620); and ascending aortic replacement with distal and proximal extension (n = 334). “Eventful recovery,” defined as occurrence of any key complications, was used as the primary end point. Odds ratios for inability to achieve uneventful recovery in each procedure were calculated using ascending aortic replacement as a reference.
Results
Overall, in-hospital mortality and stroke occurred in 16 patients (1.4%) and 24 patients (2.1%). Eventful recovery was observed in 19.7% of patients: 11.5% in those with ascending aortic replacement, 36.5% in those with partial arch or total arch replacement, 16.6% in those with proximal extension with aortic valve or root replacement, and 20.4% in those with distal and proximal extension (P < .001). With ascending aortic replacement as the reference, a multivariable logistic regression revealed partial arch or total arch replacement (odds ratio, 10.0; 95% confidence interval, 1.8-189.5) was an independent risk factor of inability to achieve uneventful recovery.
Conclusions
Open proximal aneurysm repair in the contemporary era resulted in satisfactory in-hospital outcomes. Distal extension was associated with a higher risk for postoperative complications.
Although contemporary open proximal aortic aneurysm repair results in excellent postoperative outcomes, caution must be exercised when extending the aortic replacement to the distal aortic arch.
This study showed the association between the extension of the aortic replacement and the rate of complications. The data suggest a key role of procedural type in developing risk assessment models as well as recommendations for surgical repair of aneurysm.
Thoracic aortic surgery is becoming increasingly important in adult cardiac surgery. A recent Nationwide Inpatient Sample Study showed increasing surgical procedural volumes for both proximal thoracic aortic aneurysm and acute aortic syndrome.
In the Society of Thoracic Surgeons adult cardiac surgery database, open aortic procedures accounted for 7.3% of the cases recorded between July 2017 and June 2018.
Canadian Cardiovascular Society/Canadian Society of Cardiac Surgeons/Canadian Society for Vascular Surgery Joint Position Statement on open and endovascular surgery for thoracic aortic disease.
The temporal trend of increasing case volume might enhance this practice pattern, and at this time, defining the standards in outcome measurement and quality assurance is becoming necessary in this subspecialty. A unique and wide variability in thoracic aortic surgery challenges application of a simple risk prediction model at present. Among such important variables, particularly relevant to surgeons, may be the procedure type. Previous studies have typically reported the results of certain procedures, such as aortic root replacement or total arch replacement, separately in thoracic aortic surgery
; however, there are few data to delineate the risk differences among these complex procedures. In addition to a role for risk assessment of individual patients, understanding such risk differences would have an important clinical implication for the guideline-recommended surgical indication, for which the same size criteria are currently applied for all aneurysms from the root to the arch, for each of which a different procedure would be required.
The aims of this study were (1) to describe the contemporary outcomes of various open thoracic aortic surgical procedures for proximal aortic aneurysm performed in a tertiary aortic center and (2) to investigate the influence of the procedural type on the outcomes of proximal thoracic aortic aneurysm repair.
Materials and Methods
Study Design and Patient Selection
The Columbia University Medical Center Institutional Review Board approved this study and waived the requirement for informed consent (Abbreviated Title: Outcomes in Aortic Surgery; Number: AAAR2949; First approval date: 08/10/2017; Most recent approval date: 03/11/2021).
This is a single-center retrospective study of 1132 patients with aortic aneurysm who underwent a graft replacement of the proximal aorta between March 2005 and December 2019. Proximal thoracic aorta was defined as an aortic segment from the aortic root to the proximal descending thoracic aorta.
2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the diagnosis and management of patients with thoracic aortic disease. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the diagnosis and treatment of aortic diseases of the European Society of Cardiology (ESC).
Patients who had aortic dissection or infective endocarditis and needed urgent/emergency surgery or concomitant surgery other than an aortic valve procedure were excluded. Patients were divided into 4 groups based on the extent of the aortic replacement: isolated ascending aortic replacement (ASC, n = 52); ascending aortic replacement with distal extension with hemiarch, partial arch, or total arch replacement (DST, n = 126); ascending aortic replacement with proximal extension with aortic valve replacement or aortic root replacement (PRX, n = 620); ascending aortic replacement with distal and proximal extension (D+P, n = 334); Figure 1. Preoperative demographics, procedural details, and postoperative complications (following the definition by the Society of Thoracic Surgeons Adult Cardiac Database Version 2.9 whenever available) were collected by reviewing the electronic medical record.
Figure 1Consort type diagram of patients with ASC, ascending + hemiarch, DST, PRX, or DST + PRX. ASC, Open thoracic aortic aneurysm repair undergoing isolated ascending aortic replacement; DST, partial arch or total arch replacement; PRX, ascending + aortic valve replacement or aortic root replacement; AVR, aortic valve replacement; ARR, aortic root replacement; IE, infective endocarditis; AV, aortic valve.
“Eventful recovery” was used as the primary end point. The eventful recovery was defined as occurrence of any one of the following postoperative complications, including 30-day mortality, stroke, reexploration for bleeding, respiratory failure, acute renal failure, deep sternal wound infection, postcardiotomy shock, and permanent pacemaker implantation. Our previous study in aortic root replacement showed that uneventful recovery was associated with better long-term survival.
2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the diagnosis and management of patients with thoracic aortic disease. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the diagnosis and treatment of aortic diseases of the European Society of Cardiology (ESC).
In general, for aneurysms 55 mm or larger, an open repair was recommended. For aneurysms 50 to 55 mm, repair was selectively recommended based on the individual risk profiles. For aneurysms 45 to 50 mm, a concomitant repair was performed for patients who needed aortic valve surgery. The extent of the aortic resection was per the discretion of the attending surgeon. Typically, an aortic segment of 40 mm or larger adjacent to the main aneurysm was resected. For aortic root replacement, the aortic valve was spared with reimplantation technique whenever appropriate as previously described.
Assessment of long-term outcomes: aortic valve reimplantation versus aortic valve and root replacement with biological valved conduit in aortic root aneurysm with tricuspid valve.
2020 ACC/AHA Guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.
and patient's preference. The arterial cannulation site was at the distal ascending aorta unless the resection area included the aortic arch, in which case the axillary artery was an option per the surgeon's preference.
For the arch replacement, the distal aortic anastomosis was performed typically with moderate hypothermia (24-28 °C in nasopharyngeal temperature) and antegrade cerebral perfusion. Distal systemic perfusion was temporarily halted until completion of the distal aortic anastomosis. A brief period of retrograde cerebral perfusion was selectively added to clear any air or debris from the cerebral circulation. For hemiarch replacement, unilateral antegrade cerebral perfusion through the axillary artery or innominate artery was performed unless near-infrared spectroscopy showed decreased oxygen saturation on the left head, requiring conversion to bilateral cerebral perfusion by inserting a perfusion cannula into the left carotid artery. For more extensive arch replacement, bilateral cerebral perfusion was typically used as previously described.
After the distal anastomosis was completed, systematic perfusion was resumed from the side branch of the graft. The supra-aortic vessels were individually reconstructed using a multi-branch graft.
Statistical Analysis
Variables of baseline characteristics, operative details, and in-hospital outcomes were evaluated. Continuous variables were tested for normality using the Kolmogorov–Smirnov test and found to be not normally distributed. They were expressed as medians (interquartile ranges) and analyzed using the Kruskal–Wallis test. Categorical data described with numbers and percentages of the total were compared using the Pearson's chi-square test or Fisher exact test, as appropriate. An alpha level of .05 was used to establish statistical significance of the overall test. Bonferroni correction was applied to assess the difference in variables for 6 pairwise comparisons among 4 groups of patients, categorized based on the extent of the aortic replacement. To declare statistical significance among these 4 groups, 6 different multiple comparisons must be made, so the P value must be less than .0083 (0.05 divided by 6).
Univariable logistic regression was performed to investigate the impact of each variable on our primary end point, which is the uneventful recovery. Variables significant at P less than .1 and the extent of the aortic replacement were entered into the multivariable logistic regression analysis to determine the independent risk factors associated with failure to achieve uneventful recovery. Model fit was assessed using the Hosmer–Lemeshow goodness-of-fit statistics, for which a small P value less than .05 may suggest poor fit. We also validated our model using the c-statistics, for which a value of less than .5 may indicate violation to predictive accuracy. All statistical analyses were performed with R version 4.0.0 (R Foundation for Statistical Computing).
Results
Patient Characteristics
The baseline characteristics of all patients are presented in Table 1. The median age was 60.0 [49.0-70.0] years, and 24.3% were women. The patients in the DST group were older with more comorbidities, including hypertension, cerebrovascular disease, and peripheral arterial disease, whereas coronary artery disease and chronic kidney disease were more common in PRX. Approximately half of the patients had significant aortic insufficiency, and one-quarter had AS with 38% having bicuspid aortic valve.
Median diameters of the aortic root, ascending aorta, and proximal aortic arch were 46.0 (39.0-52.0) mm, 50.0 (46.0-55.0) mm, and 34.0 (30.0-36.0) mm, respectively. The maximum aneurysm diameter was greatest in DST (56.0 [51.0-60.0] mm vs 51.0 [49.8-54.3] mm in ASC vs 50.0 [47.0-54.0] mm in PRX vs 55.0 [49.3-60.0] mm).
Operative Details
The operative details are listed in Table 2. Isolated ascending replacement was rarely performed (4.6%), with proximal extension being the most common procedure. Circulatory arrest was used for 2 patients in the ASC group and 1 patient in the PRX group. All had a history of previous cardiovascular surgery, and circulatory arrest was required to manage the severe adhesions (1 had a CentriMag [Abbott] implantation, the second had a previous ascending aortic replacement, and the third had an AVR for infective endocarditis). Among the patients in DST and D+P, hemiarch replacement was performed in 60.9% (280/460), partial arch replacement was performed in 8.0% (37/460), and total arch replacement was performed in 31.1% (143/460). In PRX, the proximal extension was AVR in 21.6% (134/620), valve-sparing aortic root replacement in 34.7% (215/620), and Bentall procedure in 43.7% (271/620). Patients with D+P underwent AVR + hemiarch replacement in 11.1% (37/334), AVR + partial/total arch replacement in 4.8% (16/334), aortic root + hemiarch replacement in 60.2% (201/334), and aortic root + partial/total arch replacement in 24.0% (80/334). The cardiopulmonary bypass time and aortic crossclamp time were longer in the descending order of D+P, DST, PRX, ASC and D+P, PRX, DST, ASC (both P < .001).
In-Hospital Mortality, Stroke, and 30-Day Mortality
The postoperative outcomes are shown in Table 3. The overall in-hospital mortality and 30-day mortality were low as 1.4% (n = 16) and 1.5% (n = 17) among 1132 patients, respectively: Three died of cardiogenic shock, 4 died of postoperative stroke, 4 died of multisystem organ failure, 2 died of septic shock, 2 died of hypovolemic shock, and 3 died of respiratory failure. The total incidence of stroke was 2.1% (n = 24).
ASC, Ascending aortic replacement; DST, ascending aortic replacement with distal extension with hemiarch, partial arch, or total arch replacement; PRX, ascending aortic replacement with proximal extension with aortic valve replacement or aortic root replacement; D+P, ascending aortic replacement with distal and proximal extension; ICU, Intensive care unit.
∗ Data are presented as median [IQR] or as number (%).
† Significantly different between ASC and DST.
‡ Significantly different between ASC and PRX.
§ Significantly different between ASC and D+P.
|| Significantly different between DST and PRX.
¶ Significantly different between DST and D+P.
# Significantly different between PRX and D+P.
∗∗ No difference in all the comparisons of the 4 groups.
The in-hospital mortality and stroke rates were 1.9% and 1.9% in ASC, 4.0% and 9.5% in DST, 0.3% and 1.1% in PRX, 2.4% and 1.2% in D+P, respectively. Of 12 patients with postoperative stroke in DST, 3 underwent hemiarch, 2 underwent partial arch replacement, and 7 underwent total arch replacement.
Eventful Recovery
Eventful recovery occurred in 19.7% of overall patients who underwent open proximal aortic aneurysm repair. As the extent of aortic replacement was expanded, the probability of eventful recovery increased: 11.5% in ASC, 16.6% in PRX, 20.4% in D+P, and 36.5% in DST. This observation was most prominent in respiratory failure: 23.8% in DST, 8.4% in D+P, 4.2% in PRX, and 5.8% in ASC; Figure 2.
Figure 2Eventful recovery rates by replacement extent after open proximal aortic aneurysm repair. AVR, Aortic valve replacement.
Analysis for the Impact of the Extent of Aortic Replacement on Uneventful Recovery
In a multivariable logistic regression analysis for eventful recovery (Table 4), DST was found to be an independent predictor of eventful postoperative recovery (odds ratio [OR], 10.0; 95% confidence interval [CI], 1.8-189.5), whereas PRX (OR, 2.8; 95% CI, 0.5-52.9) and D+P (OR, 2.7; 95% CI, 0.5-51.3) were not. Chronic kidney disease (OR, 1.8; 95% CI, 1.1-2.7) and CPB time (OR, 1.0; 95% CI, 1.0-1.1) were also shown as other predictors.
Table 4Univariable and multivariable logistic regression analysis for eventful recovery
The analysis using mixed-effect model with “surgeon” as a random effect showed results consistent with those before using the model (Table E1).
Subgroup Analysis of the Distal Extension
Table 5 shows the in-hospital outcomes of patients who underwent distal extension (DST and D+P, n = 460), divided into the hemiarch replacement group (n = 280) and the partial/total arch replacement (n = 180). In-hospital mortality and stroke rates were 1.8% and 2.5% in hemiarch replacement and 4.4% and 5.5% in partial/total arch replacement, respectively (P = .164 and .149). There was no significant difference in the rate of eventful recovery between hemiarch replacement (21.8%) and partial/total arch replacement (29.4%).
Table 5Postoperative outcomes in patients with ascending aortic replacement with distal extension with hemiarch, partial arch, or total arch replacement and ascending aortic replacement with distal and proximal extension
In the multivariable analysis for failure to uneventful recovery using hemiarch replacement as a reference, the adjusted OR of partial/total arch replacement was 0.8 (95% CI, 0.5-1.4), whereas it was 2.9 (95% CI, 1.2-6.8) in the analysis for hard end point including in-hospital mortality and stroke (Table 6).
Table 6Independent predictors of eventful recovery and combined end point of mortality or stroke in patients with ascending aortic replacement with distal extension with hemiarch, partial arch, or total arch replacement and ascending aortic replacement with distal and proximal extension
In the final model, Hosmer–Lemeshow = 0.735 and 0.713; c-statistic = 0.714 and 0.712 in each outcome. CI, Confidence interval; OR, odds ratio; CKD, chronic kidney disease; LVEF, left ventricular ejection fraction; CPB, cardiopulmonary bypass.
*Variables with P < .1 in univariable analysis were included into multivariable analysis.
The present study shows the contemporary outcomes of open proximal aortic aneurysm repair: In-hospital mortality is low with approximately 80% of uneventful recovery rate. Distal extension of aortic procedure is independently associated with higher complication rate, whereas proximal extension is not. This is the first large cohort study to examine the association between the extension of the aortic replacement and the outcome, providing important confirmatory evidence to the literature and useful clinical guidance to surgeons in deciding on the procedural type that matches the expected risk profile of individual patients. Furthermore, it provides preliminary data for future development of risk model in proximal aortic surgery.
We hypothesized that procedural type is an important factor on the outcome of thoracic aortic surgery. Our data suggest that more extensive procedures are associated with a higher complication rate. Eventful recovery after proximal aortic aneurysm repair occurred more frequently as more procedures were added to isolated ascending replacement. This was particularly significant with distal extension. Although our hypothesis and these observations have mechanical plausibility, existing literature is contradictory. Several reports claimed that addition of a hemiarch replacement to ascending aorta or aortic root replacement does not adversely affect postoperative outcomes. Sultan and colleagues
compared 116 patients each (propensity score matched) who underwent ascending aortic replacement with or without additional hemiarch replacement for aortic aneurysm and reported no significant differences in postoperative stroke, new postoperative dialysis, postoperative renal insufficiency, and 30-day mortality. Preventza and colleagues
showed similar findings in their 140 patients. An analysis of the ARCH database, including 1169 patients who underwent elective aortic arch replacement, showed that the additional of root replacement during aortic arch replacement did not increase postoperative morbidity and mortality.
On the other hand, we have reported that the addition of a hemiarch replacement in patients with a proximal aortic aneurysm has a negative impact on outcomes.
Does adding an aortic root replacement or sinus repair during arch repair increase postoperative mortality? Evidence from the Canadian Thoracic Aortic Collaborative.
also showed that the addition of aortic root manipulation to arch repair increased mortality and reoperation for bleeding.
The present study is characterized by its large cohort size and use of a unique end point, eventful recovery. Together, our dataset allowed robust, comprehensive, and relevant assessment of the influence of the procedural type on the chosen outcomes. In the context of improvement in the conventional clinical end points, such as in-hospital mortality or stroke, patients seem to be increasingly interested in expedited recovery after aneurysm repair. Eventful recovery was an outcome measure of a combined end points. Our previous study showed that eventful recovery was associated with not only prolonged hospital stay but also long-term survival after aortic root replacement.
Overall, eventful recovery occurred in approximately 20% of our cohort. The multivariable logistic regression analysis for the primary end point, eventful recovery, showed an OR of 10.0 for distal extension and 2.8 for proximal extension, compared with isolated ascending aortic replacement, supporting our hypothesis. Furthermore, partial or total arch replacement had an OR of 2.9 for a combined end point of in-hospital mortality and stroke when compared with hemiarch replacement, again in line with our hypothesis. This study informs clinicians to be mindful of the fact that extension of aortic replacement influences short-term outcomes; however, the data should not be interpreted as a suggestion to minimize the extension of the replacement. Instead, the risk associated with the aortic replacement should be balanced against the prediction of the future risk of the aortic event for individual patients.
Study Limitations
There are several limitations in the present study. The findings from this retrospective single center study may not be generalizable. Although the study included one of the largest numbers of patients for this topic, the sample size, especially the small number in the reference procedure, isolated ascending aortic replacement, precludes further in-depth analysis, such as comparing outcomes between partial arch and total arch replacement. Additionally, our sample size leads to the wide CI in the multivariable model, especially for the procedure types, calling for caution in data interpretation. Finally, although we included as many variables as possible in the model, the analytic results may be influenced by unmeasured biases. Expert surgeons make decisions often qualitatively (or subjectively) influenced by collective interpretation of preoperative or intraoperative factors, which are not necessarily included in the database, or based on the “eyeball test.” Furthermore, the quality of the aorta, such as friable tissue and degree of atherosclerosis, could not be addressed. These unmeasured confounders are likely responsible for our observation that D+P patients had more encouraging results than DST patients. In this study, the variable selection for the multivariable model based on the literature review and statistical results. The model was validated using the Hosmer–Lemeshow goodness-of-fit test and c-statistic. The results showed evidence of good fit.
Conclusions
This study confirmed that thoracic aortic surgery is not uniform while demonstrating overall low mortality and some recognizable complication rates of proximal thoracic aortic aneurysm repair in the contemporary era. It showed the association between the extension of the aortic replacement and the rate of complications. The data suggest a key role of procedural type in developing risk assessment models as well as recommendations for surgical repair of aneurysm.
The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
The authors thank Casidhe-Nicole R. Bethancourt, BS, Christian A. Pearsall, BS, Ilya Kim, BS, Diane Hu, BS, and Joshua Bergsohn, BS, for data curation.
Appendix 1
Table E1Multivariable logistic regression analysis for eventful recovery using mixed-effect model with surgeon as a random effect
Canadian Cardiovascular Society/Canadian Society of Cardiac Surgeons/Canadian Society for Vascular Surgery Joint Position Statement on open and endovascular surgery for thoracic aortic disease.
2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the diagnosis and management of patients with thoracic aortic disease. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine.
2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the diagnosis and treatment of aortic diseases of the European Society of Cardiology (ESC).
Assessment of long-term outcomes: aortic valve reimplantation versus aortic valve and root replacement with biological valved conduit in aortic root aneurysm with tricuspid valve.
2020 ACC/AHA Guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.
Does adding an aortic root replacement or sinus repair during arch repair increase postoperative mortality? Evidence from the Canadian Thoracic Aortic Collaborative.
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