Abstract
Objective
Obesity is a chronic disease linked to high mortality and morbidity after cardiac procedures, but its relationship to outcomes after total aortic arch replacement (TAR) remains unclear. We examined TAR data to determine whether obesity is associated with greater perioperative risk.
Methods
Among 787 TARs performed from 1990 to 2023, we excluded patients who lacked body mass index (BMI) data, had nonelective or nonstandard repairs, or were underweight (BMI <18.5 kg/m2). The remaining 521 patients did not have obesity (18.5 ≤BMI <30; n = 389) or did (BMI ≥30; n = 132). Patients with obesity were class 1 (30 ≤ BMI < 35), class 2 (35 ≤ BMI < 40), or class 3 (BMI ≥40). We compared preoperative and perioperative variables for BMI ≥30 (obesity) versus BMI <30. Adverse events were operative mortality, persistent stroke, spinal cord deficit, and renal failure. We performed multivariable logistic regression and Kaplan-Meier survival analysis.
Results
Patients with obesity had greater rates of obstructive sleep apnea, transient spinal cord deficit, and acute renal dysfunction than patients with normal weight. During repair, the use of antegrade cerebral perfusion often exceeded 30 minutes in patients with obesity. Operative mortality and adverse events did not differ among BMI or obesity groups. Greater BMI was not predictive of operative mortality, whereas chronic kidney disease (odds ratio, 2.28; P = .01), pulmonary disease (1.87, P < .001), longer aortic clamp time (1.01, P = .03), and antegrade cerebral perfusion time >30 minutes (2.17, P = .047) were. Survival did not differ significantly by obesity status.
Conclusions
Obesity was not associated with operative mortality or adverse events in patients who underwent TAR. Therefore, patients should not be deemed ineligible for TAR on the basis of obesity alone.
Key Words: aortic arch, obesity, postoperative complications, body mass index, cardiovascular surgical procedures
In patients undergoing total arch replacement, obesity does not increase operative risk.
Central Message.
Obesity is associated with greater risk in patients undergoing cardiac procedures. However, we did not associate obesity with greater operative mortality or morbidity after total arch replacement.
Perspective.
Obesity is correlated with greater morbidity and mortality after cardiac surgery. However, its effect on outcomes in total arch replacement (TAR) is unclear. In a multivariate analysis, we found no association between obesity and post-TAR operative mortality or morbidity, including persistent stroke, spinal cord deficit, and renal failure necessitating dialysis.
Obesity is a chronic health condition that continues to grow, affecting nearly 10% of the world's population.1,2 The implications of obesity for health are widespread because it contributes to diabetes mellitus,3 hypertension,4 cancer,5,6 and cardiovascular diseases like ischemic heart disease.7 In patients who undergo surgery, obesity is correlated with greater rates of mortality and major morbidity (eg, renal failure) after cardiac procedures.8 However, the effects of obesity on aortic arch replacement outcomes are not fully elucidated. We analyzed body mass index (BMI) data from patients who underwent elective total aortic arch replacement (TAR) to determine whether obesity is associated with greater risk of perioperative mortality and morbidity.
Methods
Study Protocol and Patient Cohort
Baylor College of Medicine's institutional review board approved our clinical research protocol (#H18095) on February 21, 2006. For patients who underwent TAR after protocol approval, clinical data were collected prospectively, and informed consent was obtained whenever possible. A waiver of consent was approved for patients who underwent surgery before the protocol was approved or whose illness prevented them from providing consent and who had no family members available to provide consent for them. Data collection before 2006 was retrospective.
Of the 3238 open aortic arch repairs performed by our single practice from 1990 to 2023, 787 (24.3%) were TARs. We excluded patients who had no BMI data (n = 34), whose TAR was nonelective (n = 205) or did not involve median sternotomy (n = 8), or who were underweight according to the World Health Organization's BMI classification (BMI <18.5 kg/m2; n = 19).9 The remaining 521 patients were categorized as healthy weight (18.5 ≤ BMI < 25; n = 165), overweight (25 ≤ BMI < 30; n = 224), or obese (BMI ≥30; n = 132); patients with obesity were categorized as class 1 (30 ≤ BMI < 35; n = 94), class 2 (35 ≤ BMI < 40; n = 29), or class 3 (BMI ≥40; n = 9). We compared patients with obesity (BMI ≥30; n = 132) and without obesity (18.5 ≤ BMI <30; n = 389).
Study Definitions and Follow-up
All data were collected by using standard definitions.10,11 Heritable thoracic aortic disease was defined as a documented connective tissue disorder (eg, Marfan, Loeys-Dietz) with or without formal clinical evaluation (ie, Ghent criteria) or genetic testing, or undergoing thoracic aortic repair at age ≤50 years. Pulmonary disease, a composite variable, comprised asthma, chronic obstructive pulmonary disease, obstructive sleep apnea, and any history of lung transplant, spontaneous pneumothorax, or tuberculosis. Each TAR incorporated at least 2 brachiocephalic arteries into the repair. We simplified the description of brachiocephalic artery reattachment during TAR to include 2 major types: an “island” approach, in which native arteries are reimplanted as a patch, and a “graft” approach, in which a bypass graft (branch graft) replaces a portion of these arteries. Reattachments involving both island and graft techniques were categorized by the dominant approach (ie, 2 of 3 vessels). Proximalization of repair described a distal anastomosis performed at the anatomic level between the left common carotid and left subclavian arteries. Following societal guidelines, operative death comprises 30-day death, in-hospital death, and death after transfer to an acute care facility.12 Adverse event was a composite end point comprising operative death, neurologic deficit, and renal failure necessitating dialysis at discharge.
Survivors of the operations were contacted for clinical follow-up approximately 60 days after repair and yearly thereafter. Postoperative surveillance information was obtained through clinic visits, telephone interviews, or written correspondence. The Social Security Death Index (up to 2011) and internet obituary searches were used to identify deaths among patients who were lost to follow-up. Patients’ overall survival was defined as the duration from the date of surgery to the date of the most recent survival status update.
Surgical Techniques
We have previously investigated various surgical techniques for total arch replacement, which have evolved over time (Figure 1, Table E1).11,13, 14, 15 All repairs involved median sternotomy and hypothermic circulatory arrest (HCA). For standard repairs in patients without obesity, arterial cannulation for cardiopulmonary bypass was performed at the right axillary, innominate, or femoral artery, or by directly cannulating the ascending aorta or another arterial site. In contemporary repair (≥2006), HCA at a moderate target temperature (24-26 °C, nasopharyngeal), is commonly used with antegrade cerebral perfusion (ACP) after either the right axillary artery or the innominate artery is cannulated. Bilateral ACP is preferred to unilateral ACP. Near-infrared spectroscopy is used to assess cerebral oxygenation in real time. Repair often extended beyond the left subclavian artery to include an elephant trunk or frozen elephant trunk approach. The introduction of collared grafts in recent years has shifted the distal anastomosis to a more proximal location (eg, between the left common carotid and left subclavian arteries instead of the traditional location distal to the left subclavian artery) and allowed greater flexibility in the management of the left subclavian artery.13 As needed, repair addresses the aortic root or aortic valve.
Figure 1.
Basic graft configurations used in total aortic arch repair: a tube graft with an island or patch reattachment, anatomic branched grafts, single and double Y-grafts, and options for classic and frozen elephant trunks. Open repair facilitates a patient-specific approach. The graft configurations shown are not an exhaustive representation. Used with permission of Baylor College of Medicine.
For patients with obesity, it is sometimes more difficult to obtain high-quality imaging studies because of logistical limitations (eg, size of patient within imaging machine) and signal attenuation related to fat mass.16 Transesophageal echocardiography is an imaging option in acute cases. In patients with obstructive sleep apnea, we ensure that they adhere to continuous positive airway pressure therapy and instruct them to bring their devices to the hospital for postoperative use. Compared with our standard approach, a larger table, longer surgical instruments, modified patient positioning, and enhanced lighting are typically needed during repair.17 Larger arterial (eg, 22-F) and venous drainage cannulas provide more blood flow during cardiopulmonary bypass, along with greater pump flow rates (6.0-7.0 L/min). Ensuring adequate blood oxygenation sometimes necessitates adding a second oxygenator to the pump to provide more surface area. This approach aims to overcome high oxygen consumption and increased carbon dioxide production. Monitoring temperature in remote locations (eg, the bladder) may be less accurate because a larger body takes longer to cool. Cannulation can be complicated by a fat pad near the right axillary artery and sometimes must be shifted to the innominate artery or another central artery. Closing the sternum in a patient with obesity can be more difficult, and the sequence of closing becomes more important. Retention sutures (ie, mattress sutures), double-wire closure, or the use of titanium sternal plates may be needed for effective sternal closure. A support bra, to take tension off the midline incision, and a wound vacuum may aid healing. We maintain a cautious approach to extubation in patients with known obstructive sleep apnea, balancing the benefits of early extubation (eg, earlier mobilization) against the risk of reintubation. We reinitiate continuous positive airway pressure therapy when clinically safe.
Statistical Analysis
Statistical analyses were performed with IBM SPSS Statistics 28 (IBM Corp), SAS version 9.4 (SAS Institute, Inc), and R, version 4.2.2, from The R Project for Statistical Computing. Continuous variables are presented as median [quartile 1-quartile 3]. Categorical variables are presented as numbers and percentages. Univariate comparisons were conducted with the Pearson χ2 test, Fisher exact test, or Wilcoxon rank-sum test.
Multivariable logistic regression models were developed from preoperative and select operative variables with clinical relevance and univariate associations with major morbidity or mortality at P ≤ .1. We entered these variables into the model, then used a backward selection method with a removal P value of .15 to build the final model. In addition, BMI was modeled as a continuous exposure using a restricted cubic spline with 4 degrees of freedom to identify linear and nonlinear associations with operative death. Predicted probabilities of operative death were obtained from the multivariable logistic regression whereas other preoperative covariates were held at their baseline values. We graphed the adjusted association between BMI and operative death as a marginal-effects plot across the observed BMI range, centered at BMI = 25 (reference), to illustrate increases or decreases in the predicted probability relative to that value. The Kaplan-Meier method estimated postoperative survival rates, which were compared between groups by using the log-rank test.
Results
Preoperative Characteristics
Compared with the patients without obesity (BMI <30; n = 389), patients with obesity (BMI ≥30; n = 132) were more likely to be male (70.5% vs 59.9%; P = .03), more often had obstructive sleep apnea (28% vs 7.5%, P < .001), and trended toward more frequent hyperlipidemia (50.0% vs 40.6%, P = .06) (Table 1).
Table 1.
Preoperative characteristics stratified by obesity
| Variable | All (N = 521) |
BMI <30 (n = 389) |
BMI ≥30 (n = 132) |
P |
|---|---|---|---|---|
| Age, y | 65 [56-72] | 66 [56-72] | 65 [56-71] | .2 |
| Male | 326 (62.6) | 233 (59.9) | 93 (70.5) | .03 |
| Heritable thoracic aortic disease | 108 (20.7) | 84 (21.6) | 24 (18.2) | .4 |
| Marfan syndrome | 57 (10.9) | 47 (12.1) | 10 (7.6) | .2 |
| Aortic aneurysm without dissection | 283 (54.3) | 217 (55.8) | 66 (50.0) | .2 |
| Chronic proximal aortic dissection | 238 (45.7) | 172 (44.2) | 66 (50.0) | .2 |
| DeBakey type I | 225 (43.2) | 162 (41.6) | 63 (47.7) | .2 |
| DeBakey type II | 11 (2.1) | 9 (2.3) | 2 (1.5) | .6 |
| Localized dissection | 3 (0.6) | 1 (0.3) | 2 (1.5) | .1 |
| Proximal (root, ascending, or arch) aortic diameter, max, cm | 5.8 [5.1-6.6] | 5.8 [5.1-6.6] | 5.8 [5.1-6.5] | .7 |
| (n = 478) | (n = 354) | (n = 124) | ||
| Distal (descending thoracic or thoracoabdominal) aortic diameter, max, cm | 5.5 [4.6-6.5] | 5.5 [4.6-6.5] | 5.6 [4.7-6.5] | .8 |
| (n = 390) | (n = 286) | (n = 104) | ||
| Hypertension | 450 (87.4) | 330 (85.9) | 120 (91.6) | .1 |
| Hyperlipidemia | 223 (43.0) | 157 (40.6) | 66 (50.0) | .06 |
| Diabetes | 42 (8.1) | 29 (7.5) | 13 (9.8) | .4 |
| Coronary artery disease | 187 (35.9) | 139 (35.7) | 48 (36.4) | .9 |
| Cerebrovascular disease | 72 (13.8) | 57 (14.7) | 15 (11.4) | .3 |
| Chronic kidney disease | 139 (26.7) | 103 (26.5) | 36 (27.3) | .9 |
| (n = 486) | (n = 359) | (n = 127) | ||
| BMI | 27 [24-30] | 26 [23-28] | 33 [31-35] | <.001 |
| Pulmonary disease | 200 (38.4) | 136 (35.0) | 64 (48.5) | .006 |
| COPD | 109 (20.9) | 81 (20.8) | 28 (21.2) | .9 |
| Obstructive sleep apnea | 66 (12.7) | 29 (7.5) | 37 (28.0) | <.001 |
| Current or former tobacco use | 340 (65.3) | 254 (65.3) | 86 (65.2) | >.99 |
| Symptoms of aneurysm | ||||
| Acute (any) | 10 (1.9) | 5 (1.3) | 5 (3.8) | .1 |
| Chronic (any) | 295 (56.6) | 215 (55.3) | 80 (60.6) | .3 |
| Prior open proximal aortic repair | 251 (48.2) | 184 (47.3) | 67 (50.8) | .5 |
Values are n (%) or median [quartile 1-quartile 3]. BMI, Body mass index; COPD, chronic obstructive pulmonary disease.
Operative Details
Most repairs in patients with obesity were performed in 2006 and later (Table 2, Table E1). There were few differences between patients with and without obesity, although patients with obesity had longer HCA duration (59 vs 54 minutes, P = .03) and more commonly had bilateral ACP (71.2% vs 53.0%, P < .001) and ACP exceeding 30 minutes (78.8% vs 63.2%, P < .001).
Table 2.
Operative details of elective repair, stratified by obesity
| Variable | All (N = 521) |
BMI <30 (n = 389) |
BMI ≥30 (n = 132) |
P |
|---|---|---|---|---|
| Reoperation | 270 (51.8) | 198 (50.9) | 72 (54.5) | .5 |
| Surgical era | ||||
| <2006 | 153 (29.4) | 129 (33.2) | 24 (18.2) | .001 |
| ≥2006 | 368 (70.6) | 260 (66.8) | 108 (81.8) | .001 |
| Arterial cannulation site (initial) | ||||
| Direct aorta (ascending/arch) | 86 (16.5) | 69 (17.7) | 17 (12.9) | .2 |
| Right axillary | 229 (44.0) | 166 (42.7) | 63 (47.7) | .3 |
| Innominate | 112 (21.5) | 81 (20.8) | 31 (23.5) | .5 |
| Right common carotid | 20 (3.8) | 12 (3.1) | 8 (6.1) | .1 |
| Femoral | 68 (13.1) | 56 (14.4) | 12 (9.1) | .1 |
| Other/unknown | 6 (1.2) | 6 (1.5) | 0 | .2 |
| Primary brachiocephalic artery reattachment approach | ||||
| Island (≥2 vessels) | 277 (53.2) | 208 (53.5) | 69 (52.3) | .8 |
| Graft (≥2 vessels) | 229 (44.0) | 172 (44.2) | 57 (43.2) | .8 |
| LSCA management | ||||
| Preoperative bypass/transposition | 31 (6.0) | 20 (5.1) | 11 (8.3) | .3 |
| Intraoperative bypass/transposition | 136 (26.1) | 104 (26.7) | 32 (24.2) | .6 |
| Reimplantation or island | 201 (38.6) | 152 (39.1) | 49 (37.1) | .7 |
| Native (not incorporated) | 146 (28.0) | 108 (27.8) | 38 (28.8) | .8 |
| Other | 7 (1.3) | 5 (1.3) | 2 (1.5) | .8 |
| Aortic repair details (proximal) | ||||
| Isolated AV replacement | 85 (16.3) | 55 (14.1) | 30 (22.7) | .02 |
| Aortic root replacement | 62 (11.9) | 46 (11.8) | 16 (12.1) | .9 |
| Aortic repair details (distal) | ||||
| Proximalization of repair∗ | 190 (36.5) | 134 (34.4) | 56 (42.4) | .1 |
| Reverse ET | 20 (3.8) | 11 (2.8) | 9 (6.8) | .04 |
| ET | 393 (75.4) | 295 (75.8) | 98 (74.2) | .7 |
| Classic | 266 (51.1) | 202 (51.9) | 64 (48.5) | .5 |
| Frozen | 127 (24.4) | 93 (23.9) | 34 (25.8) | .7 |
| Perfusion and ischemic times, min | ||||
| Aortic clamp time | 54 [27-80] | 54 [27-82] | 53 [31-76] | >.9 |
| (n = 434) | (n = 322) | (n = 112) | ||
| CPB time | 138 [107-182] | 136 [104-180] | 143 [117-191] | .2 |
| HCA systemic time | 55 [44-69] | 54 [43-67] | 59 [46-73] | .03 |
| Lowest nasopharyngeal temperature, °C | 21 [15-23] | 20 [14-23] | 22 [17-24] | .005 |
| Cerebral perfusion | ||||
| None | 35 (6.7) | 30 (7.7) | 5 (3.8) | .1 |
| RCP (any) | 105 (20.2) | 88 (22.6) | 17 (12.9) | .02 |
| ACP (any) | 400 (76.8) | 287 (73.8) | 113 (85.6) | .005 |
| ACP and RCP | 19 (3.6) | 16 (4.1) | 3 (2.3) | .3 |
| Bilateral ACP | 300 (57.6) | 206 (53.0) | 94 (71.2) | <.001 |
| ACP time, min | 58 [44-73] | 56 [43-72] | 60 [47-74] | .1 |
| (n = 400) | (n = 287) | (n = 113) | ||
| ACP time >30 min | 361 (67.1) | 251 (63.2) | 104 (78.8) | <.001 |
| Concomitant procedure | ||||
| Cerebrospinal fluid drainage | 17 (3.3) | 11 (2.8) | 6 (4.5) | .3 |
| Coronary artery bypass grafting | 89 (17.1) | 71 (18.3) | 18 (13.6) | .2 |
Values are n (%) or median [quartile 1-quartile 3]. BMI, Body mass index; LSCA, left subclavian artery; AV, aortic valve; ET, elephant trunk; CPB, cardiopulmonary bypass; HCA, hypothermic circulatory arrest; RCP, retrograde cerebral perfusion; ACP, antegrade cerebral perfusion.
Proximalization of repair was defined as the distal anastomosis performed at the anatomic level between the left common carotid and left subclavian arteries or more proximally.
Early Outcomes
Patients with obesity did not have greater rates of composite adverse events (16.7% vs 17.7%, P = .8), operative death (12.9% vs 12.1%, P = .8), persistent stroke (3.8% vs 5.9%, P = .4), or any pulmonary complication (Table E2) than patients without obesity. However, they did have greater rates of transient spinal cord deficit (4.5% vs 1.3%, P = .02) and acute renal dysfunction (20.5% vs 11.3%, P = .008) and trended toward more frequent atrial arrythmia (39.4% vs 31.9%, P = .1) (Table 3). One patient without obesity developed persistent paraplegia after TAR repair with a frozen elephant trunk approach. Regarding the cause of operative death, there were few notable differences between patients with and without obesity (Table E3).
Table 3.
Early outcomes stratified by obesity
| Variable | All (N = 521) |
BMI <30 (n = 389) |
BMI ≥30 (n = 132) |
P |
|---|---|---|---|---|
| Adverse event∗ | 91 (17.5) | 69 (17.7) | 22 (16.7) | .8 |
| Operative death | 64 (12.3) | 47 (12.1) | 17 (12.9) | .8 |
| 30-d death | 47 (9.0) | 34 (8.7) | 13 (9.8) | .7 |
| Neurologic deficit | ||||
| Stroke | 35 (6.7) | 29 (7.5) | 6 (4.5) | .2 |
| Persistent stroke† | 28 (5.4) | 23 (5.9) | 5 (3.8) | .4 |
| Persistent spinal cord deficit | 7 (1.3) | 5 (1.3) | 2 (1.5) | .8 |
| Transient spinal cord deficit‡ | 11 (2.1) | 5 (1.3) | 6 (4.5) | .02 |
| Acute renal dysfunction | 71 (13.6) | 44 (11.3) | 27 (20.5) | .008 |
| Renal failure necessitating dialysis | 42 (8.1) | 32 (8.2) | 10 (7.6) | .8 |
| Persistent renal failure† | 36 (6.9) | 29 (7.5) | 7 (5.3) | .4 |
| Cardiac complication | 262 (50.3) | 195 (50.1) | 67 (50.8) | .9 |
| New-onset MI | 6 (1.2) | 3 (0.8) | 3 (2.3) | .2 |
| Arrythmia (any) | 204 (39.2) | 151 (38.8) | 53 (40.2) | .8 |
| Atrial arrythmia | 176 (33.8) | 124 (31.9) | 52 (39.4) | .1 |
| Pulmonary complication | 249 (47.8) | 192 (49.4) | 57 (43.2) | .2 |
| Respiratory failure | 212 (40.7) | 160 (41.1) | 52 (39.4) | .7 |
| Necessitating tracheostomy | 78 (15.0) | 59 (15.2) | 19 (14.4) | .8 |
| Bleeding requiring reoperation | 17 (3.3) | 16 (4.1) | 1 (0.8) | .1 |
| Sternal wound infection§ | 20 (3.8) | 13 (3.3) | 7 (5.3) | .4 |
| Operative survivors | 457 (87.7) | 342 (87.9) | 115 (87.1) | .8 |
| Length of ICU stay, d | 5 [3-12] (n = 440) |
5 [3-12] (n = 327) |
5 [2-12] (n = 113) |
.6 – |
| Length of hospital stay, d | 12 [9-22] (n = 449) |
13 [9-22] (n = 334) |
12 [8-23] (n = 115) |
.5 – |
Values are n (%) or median [quartile 1-quartile 3]. BMI, Body mass index; MI, myocardial infarction; ICU, intensive care unit.
Defined as operative death or persistent (present at hospital discharge) stroke, paraplegia, paraparesis, or renal failure necessitating dialysis.
Present at the time of hospital discharge or early death.
A frozen elephant trunk approach was used in 8 of 11 patients (BMI ≥30; n = 5/6).
Sternal wounds were superficial (n = 19) or deep (n = 1; mediastinitis).
Obesity by Class
There were few differences in characteristics of patients with obesity stratified by class. Notably, those with class 1 obesity (30 ≤ BMI < 35) were more likely to undergo reoperation and aortic root replacement than patients with class 2 (35 ≤ BMI < 40) and class 3 obesity (BMI ≥40) (Table 4).
Table 4.
Comparative analysis of obesity stratified by class
| Variable | Class 1 30 ≤ BMI < 35 (n = 94) |
Class 2 35 ≤ BMI < 40 (n = 29) |
Class 3 BMI ≥40 (n = 9) |
Classes 2 and 3 BMI ≥35 (n = 38) |
P∗ |
|---|---|---|---|---|---|
| Age, y | 65 [57-71] | 64 [52-71] | 59 [52-67] | 64 [53-69] | .8 |
| Male | 68 (72) | 18 (62) | 7 (78) | 25 (66) | .5 |
| Heritable thoracic aortic disease | 15 (16) | 6 (21) | 3 (33) | 9 (24) | .3 |
| Chronic proximal aortic dissection | 51 (54) | 13 (45) | 2 (22) | 15 (40) | .1 |
| Diabetes | 7 (7) | 5 (17) | 1 (11) | 6 (16) | .1 |
| Coronary artery disease | 36 (38) | 9 (31) | 3 (33) | 12 (32) | .5 |
| Previous stroke | 9 (10) | 2 (7) | 1 (11) | 3 (8) | .8 |
| BMI | 32 [31-33] | 36 [35-38] | 43 [40-45] | 37 [36-40] | <.001 |
| Reoperation | 57 (61) | 10 (35) | 5 (56) | 15 (40) | .03 |
| Femoral cannulation | 9 (10) | 3 (10) | 0 | 3 (8) | .8 |
| Aortic clamp time, min | 54 [30-82] | 53 [33-72] | 51 [13-73] | 52 [32-71] | .9 |
| ACP time >30 min, n | 74 (79) | 21 (72) | 9 (100) | 30 (79) | >.9 |
| Aortic root replacement | 15 (16) | 1 (3) | 0 | 1 (3) | .03 |
| Elephant trunk | 70 (75) | 23 (79) | 5 (56) | 28 (74) | .9 |
| Frozen elephant trunk | 21 (22) | 10 (35) | 3 (33) | 13 (34) | .2 |
| Adverse event (composite) | 18 (19) | 2 (7) | 2 (22) | 4 (11) | .2 |
| Operative mortality | 13 (14) | 2 (7) | 2 (22) | 4 (11) | .6 |
| Persistent stroke† | 4 (4) | 0 | 1 (11) | 1 (3) | .7 |
| Persistent paraparesis† | 2 (2) | 0 | 0 | 0 | .4 |
| Persistent paraplegia† | 0 | 0 | 0 | 0 | — |
| Persistent renal failure (dialysis)† | 9 (10) | 1 (3) | 0 | 1 (3) | .2 |
| Sternal wound infection | 4 (4) | 3 (10) | 0 | 3 (8) | .4 |
| Early survivors: ICU LOS, d | 5 [2-12] | 5 [3-11] | 6 [2-13] | 6 [2-12] | .6 |
| Early survivors: overall LOS, d | 11 [8-25] | 15 [8-24] | 12 [8-15] | 14 [8-19] | .5 |
Values are n (%) or median [quartile 1-quartile 3]. Obesity is further grouped into class 1 (30 ≤ BMI < 35; n = 94 [71.2%]), class 2 (35 ≤ BMI < 40; n = 29 [21.9%]), and class 3 (BMI≥40; n = 9 [6.9%]). BMI, Body mass index; ACP, antegrade cerebral perfusion; ICU, intensive care unit; LOS, length of stay.
P value compares class 1 versus a combined class 2 and 3.
Present at the time of hospital discharge or early death.
Findings From Modeling
Overall, the multiple logistic regression model showed that certain preoperative and operative features, including chronic kidney disease (odds ratio [OR], 2.19, P = .01), pulmonary disease (OR, 2.50; P = .005), tobacco use (OR, 2.22; P = .03), and ACP time >30 minutes (OR, 2.69; P = .01), were better predictors of operative death than BMI ≥30 (OR, 0.99; P = .8) or age (OR, 1.01; P = .7) (Table 5). When BMI was modeled as a continuous variable to capture variations at lower BMI values, with 25 kg/m2 as the reference point, the analysis revealed no significant association between BMI and operative mortality. As Figure E1 shows, the OR remained close to 1 across the BMI range, and the confidence intervals consistently crossed the no-effect line, indicating no significant associations.
Table 5.
Logistic regression model for predicting operative death in patients after elective total arch replacement
| Variable | Odds ratio (95% CI) | P value |
|---|---|---|
| Age, y | 1.01 (0.98-1.04) | .7 |
| Body mass index ≥30 | 0.99 (0.93-1.06) | .8 |
| Chronic kidney disease | 2.19 (1.14-4.17) | .01 |
| Pulmonary disease | 2.50 (1.32-4.81) | .005 |
| Current or former tobacco use | 2.22 (1.07-4.97) | .03 |
| Aortic clamp time, min | 1.01 (1.00-1.01) | .058 |
| ACP time >30 min, n | 2.69 (1.22-6.62) | .01 |
ACP, Antegrade cerebral perfusion.
Figure E1.
Restricted cubic spline from a multivariable logistic regression model depicting the predicted probability of operative death across the observed BMI range. The horizontal dotted line marks OR = 1.0, which represents no effect. Values above this line indicate greater risk, whereas values below indicate lower risk. The vertical dotted line marks BMI = 25 kg/m2 to indicate changes in predicted probability around this value. The predicted OR line is slightly above the no-effect line for BMI values <25 and below it for BMI values >25. The 95% CIs cross the no-effect line at all points, indicating no significant associations. BMI, Body mass index.
Late Outcomes
Overall survival for patients with and without obesity was not significantly different (P = .6) (Figure 2).
Figure 2.
Kaplan-Meier estimated survival for all patients (n = 521) who underwent elective total aortic arch replacement, stratified by obesity (body mass index [BMI] ≥30). Shown are a snapshot of earliest death (≤60 days; A) and overall survival (≤10 years; B). The 95% CIs are shown as shaded regions.
Discussion
We hypothesized that obesity would be associated with greater operative mortality and morbidity (eg, stroke) in patients who undergo elective TAR. Our results showed no substantial difference in perioperative mortality between patients with and without obesity, or among different degrees of obesity. Obstructive sleep apnea, a component of pulmonary disease, was more common in patients with obesity than without obesity. The durations of complex portions of the repair (eg, HCA and HCA with ACP) were longer in patients with obesity than in patients than without obesity. Patients with obesity had greater rates of transient spinal cord deficit and acute renal dysfunction but not of persistent spinal cord deficit or renal failure. It is possible that patients with obesity are more susceptible to spinal cord deficits after frozen elephant trunk approaches. Modeling showed that operative survival in patients with and without obesity was most closely related to pulmonary disease and chronic kidney disease.
This work is timely because the few studies that have investigated the relationship between obesity and aortic arch surgery dealt with nonelective cases (eg, aortic dissection repairs).18, 19, 20, 21 These studies associated obesity with postoperative severe hypoxemia,18 postoperative acute kidney injury,21 operative mortality, low cardiac output syndrome, pulmonary complications, and 5-year mortality.19 Although this study did not show worse permanent outcomes in patients with obesity, we nonetheless advocate optimizing preoperative variables such as obstructive sleep apnea ahead of surgery.
The absence of any significant association between obesity and mortality or persistent complications in patients who undergo TAR was surprising, because obesity is an important risk factor in nonelective TAR. This unexpected finding is important because it suggests that obesity should not preclude patients from undergoing elective TAR, even though surgeons can reasonably expect portions of these repairs to take longer in patients with obesity than in patients without obesity.
Limitations of this study include a heterogeneous cohort and highly variable repair strategies. Our study period was long because we elected to use a broad time frame to maximize cohort size. Fewer patients with obesity underwent repair before 2006, which may reflect a temporal shift in patient selection; additional bias could have arisen from referral patterns inherent to a tertiary care center. We had few patients with extreme obesity (class 3); these patients might not be referred for repair. In addition, we were unable to robustly evaluate surgical era as pertains to outcomes in patients with obesity. Our data collection shifted from retrospective to prospective in 2006. As a result, data on some outcomes—particularly operative mortality—were probably less complete in the earlier era, especially for patients who died after transfer to a long-term acute care facility. Likewise, others have suggested that surgical risk associated with TAR is underestimated when 30-day death is used as a primary measure because postoperative complications compromise survival in the early months of recovery.22
Conclusions
TAR is a complex procedure with substantial operative mortality even when elective; nonetheless, the association between obesity and surgical risk in such patients, which was previously uncharacterized, appears to be minimal. Our results suggest that obesity alone should not disqualify patients from undergoing this operation.
Conflict of Interest Statement
Dr Orozco-Sevilla participates in clinical trials for Gore Medical, Cook Medical, and Terumo Aortic and consults for Cook Medical. Dr Chatterjee has served on advisory boards for Edwards Lifesciences, Eagle Pharmaceuticals, La Jolla Pharmaceutical Company, and Baxter Lifesciences. Dr LeMaire serves as a consultant for Cerus. Dr Moon serves on an advisory board for Edwards Lifesciences. Dr Coselli consults for and participates in clinical trials for Terumo Aortic, Medtronic, Inc, and W.L. Gore & Associates and participates in clinical trials for Abbott Laboratories, Artivion, AstraZeneca, and Edwards Lifesciences. All other authors reported no conflicts of interest.
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.
Acknowledgments
The authors thank Vivek Ramanathan, MS, and Uma Ramamurthy, PhD, MBA, of the Office of Research IT at Baylor College of Medicine for data management support, and several members of the Michael E. DeBakey Department of Surgery at Baylor College of Medicine: Scott A. Weldon, MA, CMI, FAMI, for creating several of the illustrations; Stephen N. Palmer, PhD, ELS, for providing editorial support; and Arin C. Jobe, MPH, Lora Alomari, MS, and Katia Matar, BS, for providing project support. Endowments from the E. Stanley Crawford Endowment (Mr Weldon), The Denton A. Cooley, MD, Chair in Cardiac Surgery (MRM), and the Cullen Foundation Endowed Chair at Baylor College of Medicine (JSC) provided partial support. Sincere thanks to James L. Dettore, Chief Executive Officer and Chairman of Brand Institute, for his generous support of our Dettore Database.
Footnotes
M.T.G. was supported by the Baylor College of Medicine T32 Research Training Program in Cardiovascular Surgery (T32HL139430).
Dr Subhasis Chatterjee, MD, is a Feature Editor. The peer review process for this paper was handled by Dr Leonard N. Girardi, MD.
Appendix E1
Table E1.
Stratification of select variables by surgical era
| Variables | All (N = 521) |
Repair <2006 (n = 153) |
Repair ≥2006 (n = 368) |
P |
|---|---|---|---|---|
| Preoperative characteristics | ||||
| Age, y | 65 [56-72] | 66 [57-72] | 65 [56-72] | .3 |
| Heritable thoracic aortic disease | 108 (20.7) | 33 (21.6) | 75 (20.4) | .8 |
| Chronic proximal aortic dissection | 238 (45.7) | 55 (35.9) | 183 (49.7) | .004 |
| Proximal aortic diameter, max, cm | 5.8 [5.1-6.6] | 6.2 [5.5-7.0] | 5.6 [5.0-6.3] | <.001 |
| BMI <30 | 389 (74.7) | 129 (84.3) | 260 (70.7) | .001 |
| BMI ≥30 | 132 (25.3) | 24 (15.7) | 108 (29.3) | .001 |
| Diabetes | 42 (8.1) | 10 (6.5) | 32 (8.7) | .4 |
| Coronary artery disease | 187 (35.9) | 66 (43.1) | 121 (32.9) | .03 |
| Chronic kidney disease | 136 (28.0) | 46 (34.1) | 90 (25.6) | .06 |
| Pulmonary disease | 200 (38.4) | 55 (35.9) | 145 (39.4) | .5 |
| Obstructive sleep apnea | 66 (12.7) | 5 (3.3) | 61 (16.6) | <.001 |
| Current or former tobacco use | 340 (65.3) | 111 (72.5) | 229 (62.2) | .02 |
| Operative details | ||||
| Reoperation (redo incision) | 270 (51.8) | 60 (39.2) | 210 (57.1) | <.001 |
| Arterial cannulation site (initial) | ||||
| Direct aorta (ascending/arch) | 86 (16.5) | 71 (46.4) | 15 (4.1) | <.001 |
| Right axillary | 229 (44.0) | 15 (9.8) | 214 (58.2) | <.001 |
| Innominate | 112 (21.5) | 0 | 112 (30.4) | <.001 |
| Right common carotid | 20 (3.8) | 0 | 20 (5.4) | .003 |
| Femoral | 68 (13.1) | 64 (41.8) | 4 (1.1) | <.001 |
| Other or unknown | 6 (1.2) | 2 (1.3) | 4 (1.1) | .8 |
| Primary brachiocephalic reattachment | ||||
| Island (≥2 vessels) | 278 (53.4) | 134 (87.6) | 144 (39.1) | <.001 |
| Graft (≥2 vessels) | 243 (46.6) | 19 (12.4) | 224 (60.9) | <.001 |
| Other repair details | ||||
| Aortic clamp time, min | 54 [27-80] | 50 [25-71] | 54 [28-87] | .9 |
| Proximalization of repair (LCCA-LSCA) | 221 (42.4) | 31 (20.3) | 190 (51.6) | <.001 |
| ET | 393 (75.4) | 103 (67.3) | 290 (78.8) | .006 |
| Classic ET | 266 (51.1) | 103 (67.3) | 163 (44.3) | <.001 |
| Frozen ET∗ | 127 (24.4) | 0 | 127 (34.5) | <.001 |
| Lowest nasopharyngeal temp, °C | 21 [16-23] | 13 [11-15] | 22 [20-24] | <.001 |
| Cerebral perfusion | ||||
| None | 35 (6.7) | 34 (22.2) | 1 (0.3) | <.001 |
| Any RCP | 105 (20.2) | 101 (66.0) | 4 (1.1) | <.001 |
| Any ACP | 400 (76.8) | 33 (21.6) | 367 (99.7) | <.001 |
| ACP time >30 min, n | 361 (69.3) | 9 (5.9) | 352 (95.7) | <.001 |
| Early outcomes | ||||
| Adverse event† | 91 (17.5) | 19 (12.4) | 72 (19.6) | .05 |
| Operative death | 64 (12.3) | 11 (7.2) | 53 (14.4) | .02 |
| 30-d death | 47 (9.0) | 10 (6.5) | 37 (10.1) | .2 |
| Persistent stroke‡ | 28 (5.4) | 7 (4.6) | 21 (5.7) | .6 |
| Spinal cord deficit | 15 (2.9) | 2 (1.3) | 13 (3.5) | .2 |
| Transient spinal cord deficit | 11 (2.1) | 1 (0.7) | 10 (2.7) | .1 |
| Persistent paraplegia‡ | 1 (0.2) | 0 | 1 (0.3) | .5 |
| Acute renal dysfunction | 71 (13.6) | 9 (5.9) | 62 (16.8) | <.001 |
| Persistent renal failure‡ | 36 (6.9) | 5 (3.3) | 31 (8.4) | .04 |
| Respiratory failure necessitating tracheostomy | 78 (15.0) | 22 (14.4) | 56 (15.2) | .8 |
| Arrythmia (any) | 204 (39.2) | 55 (35.9) | 149 (40.5) | .3 |
| Bleeding requiring reoperation | 17 (3.3) | 3 (2.0) | 14 (3.8) | .3 |
| Wound infection | 21 (4.0) | 9 (5.9) | 12 (3.3) | .2 |
| Sternal wound§ | 20 (3.8) | 8 (5.2) | 12 (3.3) | .3 |
| Groin wound | 2 (0.4) | 1 (0.7) | 1 (0.3) | .5 |
Values are n (%) or median [quartile 1-quartile 3]. BMI, Body mass index; LCCA, left common carotid artery; LSCA, left subclavian artery; ET, elephant trunk; RCP, retrograde cerebral perfusion; ACP, antegrade cerebral perfusion.
Frozen elephant trunks include “homemade” approaches that rely on an elephant trunk graft with antegrade endograft deployment in addition to commercially available hybrid devices.
Defined as operative death or persistent (present at hospital discharge) stroke, paraplegia, paraparesis, or renal failure necessitating dialysis.
Present at the time of hospital discharge or early death; this patient did not have obesity.
Sternal wounds were superficial (n = 19) or deep (n = 1; mediastinitis).
Table E2.
Expansion of pulmonary complications stratified by obesity
| Variable | All (N = 521) |
BMI <30 (n = 389) |
BMI ≥30 (n = 132) |
P |
|---|---|---|---|---|
| Pulmonary complication | 249 (47.8) | 192 (49.4) | 57 (43.2) | .2 |
| Respiratory failure | 212 (40.7) | 160 (41.1) | 52 (39.4) | .7 |
| Necessitating tracheostomy | 78 (15.0) | 59 (15.2) | 19 (14.4) | .8 |
| Need for reintubation | 120 (23.0) | 93 (23.9) | 27 (20.5) | .4 |
| Acute respiratory distress | 28 (5.4) | 21 (5.4) | 7 (5.3) | >.9 |
| Atelectasis necessitating bronchoscopy | 47 (9.0) | 34 (8.7) | 13 (9.8) | .7 |
| Chylothorax | 0 | 0 | 0 | – |
| Drainage of pleural effusion | 1 (0.2) | 0 | 1 (0.8) | .1 |
| Pneumonia | 43 (8.3) | 1 (8.0) | 12 (9.1) | .7 |
| Evacuation of pneumothorax | 15 (2.9) | 13 (3.3) | 2 (1.5) | .3 |
| Pulmonary embolism | 7 (1.3) | 7 (1.8) | 0 | .1 |
Values are n (%). Pulmonary complication is a composite of all other variables in this table. In this set of patients, no patient developed postoperative chylothorax. Respiratory failure is a composite variable that describes ventilator dependence exceeding 48 hours before the time of discharge and includes failure necessitating tracheostomy and need for reintubation. BMI, Body mass index.
Table E3.
Primary causes of operative death∗ for 64 patients
| Variable | All (N = 64) |
BMI <30 (n = 47) |
BMI ≥30 (n = 17) |
|---|---|---|---|
| Multisystem organ failure | 18 | 15 | 3 |
| Multisystem organ failure with sepsis | 5 | 3 | 2 |
| Stroke with and without MSOF and other factors | 10 | 7 | 3 |
| Cardiac failure | 9 | 4 | 5 |
| Unknown† | 7 | 7 | 0 |
| Coagulopathy with and without MSOF and other factors | 5 | 5 | 0 |
| Pulmonary embolism | 3 | 3 | 0 |
| Cardiopulmonary failure, including sudden events | 3 | 1 | 2 |
| Respiratory failure | 2 | 0 | 2 |
| Myocardial infarction | 2 | 1 | 1 |
| Pneumonia | 1 | 1 | 0 |
| Rupture | 1 | 1 | 0 |
| Pericardial effusion after discharge to home | 1 | 0 | 1 |
| Heparin-induced thrombocytopenia | 1 | 1 | 0 |
| Fistula | 1 | 1 | 0 |
Values are n. BMI, Body mass index; MSOF, multiple system organ failure.
We defined operative death as death within 30 days of surgery or before final hospital discharge, including any death after transfer to another hospital.
Unknown deaths typically occurred after transfer to a long-term acute care facility or after discharge home within 30 days of repair.
References
- 1.Lopez-Jimenez F., Almahmeed W., Bays H., et al. Obesity and cardiovascular disease: mechanistic insights and management strategies. A joint position paper by the World Heart Federation and World Obesity Federation. Eur J Prev Cardiol. 2022;29(17):2218–2237. doi: 10.1093/eurjpc/zwac187. [DOI] [PubMed] [Google Scholar]
- 2.World Health Organization Fact sheet: obesity and overweight. 2025. https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
- 3.Bays H.E., Taub P.R., Epstein E., et al. Ten things to know about ten cardiovascular disease risk factors. Am J Prev Cardiol. 2021;5 doi: 10.1016/j.ajpc.2021.100149. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Wilson P.W., D'Agostino R.B., Sullivan L., Parise H., Kannel W.B. Overweight and obesity as determinants of cardiovascular risk: the Framingham experience. Arch Intern Med. 2002;162(16):1867–1872. doi: 10.1001/archinte.162.16.1867. [DOI] [PubMed] [Google Scholar]
- 5.Karra P., Winn M., Pauleck S., et al. Metabolic dysfunction and obesity-related cancer: beyond obesity and metabolic syndrome. Obesity (Silver Spring) 2022;30(7):1323–1334. doi: 10.1002/oby.23444. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Cercato C., Fonseca F.A. Cardiovascular risk and obesity. Diabetol Metab Syndr. 2019;11:74. doi: 10.1186/s13098-019-0468-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Usmanov M.M., Chimed-Ochir O., Batkhorol B., Yumiya Y., Hujamberdieva L.M., Kubo T. Obesity, burden of ischemic heart diseases and their ecological association: the case of Uzbekistan. Int J Environ Res Public Health. 2022;19(16) doi: 10.3390/ijerph191610447. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Ghanta R.K., LaPar D.J., Zhang Q., et al. Obesity increases risk-adjusted morbidity, mortality, and cost following cardiac surgery. J Am Heart Assoc. 2017;6(3) doi: 10.1161/JAHA.116.003831. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Centers for Disease Control and Prevention Adult BMI categories. https://www.cdc.gov/bmi/adult-calculator/bmi-categories.html
- 10.Preventza O., Price M.D., Simpson K.H., et al. Hemiarch and total arch surgery in patients with previous repair of acute type I aortic dissection. Ann Thorac Surg. 2015;100(3):833–838. doi: 10.1016/j.athoracsur.2015.03.095. [DOI] [PubMed] [Google Scholar]
- 11.Coselli J.S., Frankel W.C., Green S.Y., et al. Staged repair of extensive aneurysms of the thoracic aorta by using the elephant trunk technique. Ann Thorac Surg. 2022;114(5):1578–1585. doi: 10.1016/j.athoracsur.2021.09.078. [DOI] [PubMed] [Google Scholar]
- 12.Overman D.M., Jacobs J.P., Prager R.L., et al. Report from the Society of Thoracic Surgeons National Database Workforce: clarifying the definition of operative mortality. World J Pediatr Congenit Heart Surg. 2013;4(1):10–12. doi: 10.1177/2150135112461924. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Orozco-Sevilla V., Coselli J.S. Management of the left subclavian artery during aortic arch replacement using a frozen elephant trunk approach: a review. Cardiovasc Diagn Ther. 2023;13(4):736–742. doi: 10.21037/cdt-22-248. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Amin A., Etheridge G.M., Amarasekara H.S., Green S.Y., Orozco-Sevilla V., Coselli J.S. Aortic arch repair: lessons learned over three decades at Baylor College of Medicine. J Cardiovasc Surg (Torino) 2022;63(4):393–405. doi: 10.23736/S0021-9509.22.12376-1. [DOI] [PubMed] [Google Scholar]
- 15.Orozco-Sevilla V., Coselli J.S., Green S.Y., et al. Total aortic arch replacement using the Thoraflex Hybrid device: evolution from investigational to federally approved use in the United States. Ann Cardiothorac Surg. 2025;14(4):279–290. doi: 10.21037/acs-2025-evet-0070. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Nabasenja C., Barry K., Nelson T., Chandler A., Hewis J. Imaging individuals with obesity. J Med Imaging Radiat Sci. 2022;53(2):291–304. doi: 10.1016/j.jmir.2022.02.003. [DOI] [PubMed] [Google Scholar]
- 17.Hui D.S., Lizalek J.M., Chawa V.S., Lee R. Operative techniques for improving surgical exposure in basic cardiac surgery. J Vis Surg. 2018;4:80. doi: 10.21037/jovs.2018.03.19. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Gong M., Wu Z., Xu S., et al. Increased risk for the development of postoperative severe hypoxemia in obese women with acute type A aortic dissection. J Cardiothorac Surg. 2019;14(1):81. doi: 10.1186/s13019-019-0888-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Lio A., Bovio E., Nicolo F., et al. Influence of body mass index on outcomes of patients undergoing surgery for acute aortic dissection: a propensity-matched analysis. Tex Heart Inst J. 2019;46(1):7–13. doi: 10.14503/THIJ-17-6365. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Shimizu T., Kimura N., Mieno M., et al. Effects of obesity on outcomes of acute type A aortic dissection repair in Japan. Circ Rep. 2020;2(11):639–647. doi: 10.1253/circrep.CR-20-0098. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Liu T., Fu Y., Liu J., et al. Body mass index is an independent predictor of acute kidney injury after urgent aortic arch surgery for acute DeBakey type I aortic dissection. J Cardiothorac Surg. 2021;16(1):145. doi: 10.1186/s13019-021-01533-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Rajesh K., Levine D., Murana G., et al. Is surgical risk of aortic arch aneurysm repair underestimated? A novel perspective based on 30-day versus 1-year mortality. Eur J Cardiothorac Surg. 2024;65(3) doi: 10.1093/ejcts/ezae041. [DOI] [PubMed] [Google Scholar]