Thoracic Endovascular Aortic Repair (TEVAR) After Prior Thoracic Open or Endovascular Repair is Not Associated with Increased Risk of Spinal Cord Ischemia or 30-Day Mortality
Ryan W King, Mathew D Wooster, Jean M Ruddy, Elizabeth A Genovese, Thomas E Brothers, Ravi K Veeraswamy
Medical University of South Carolina, Charleston, SC
BACKGROUND: A large percentage of patients who undergo aortic surgery have had prior endovascular or open aortic repairs. This is especially true for those who were treated for extensive thoracic and abdominal aortic pathology, although less data exist for those who have re-interventions for disease isolated to the thoracic aorta. Some studies evaluating outcomes following repeat aortic repairs have found prior aortic repair to not be associated with increased mortality, but there are mixed conclusions regarding the protective effect against spinal cord ischemia and other post-operative morbidities. The current study aims to evaluate 30-day mortality and post-operative spinal cord ischemia following thoracic endovascular aortic repair (TEVAR) after prior TEVAR or open thoracic aortic repair, as well as outcomes following TEVAR without prior repair using data obtained through the Vascular Quality Initiative (VQI).
METHODS: All cases of TEVAR from 2012 to 2018 in the VQI were queried for cases with complete data on 30-day mortality and post-operative spinal cord ischemia. Cases of TEVARs extending beyond aortic zone 6 into the abdominal aorta were excluded along with cases of patients who had prior abdominal aortic repair. Descriptions of aortic zones were consistent with the Society for Vascular Surgery reporting standards, Figure 1. Primary outcomes were 30-day mortality and post-operative spinal cord ischemia. Cases of spinal cord ischemia included all events of transient or permanent lower extremity neurologic deficits. Secondary endpoints included post-operative outcomes: retreatment, stroke, cardiac complications, pulmonary complications, and post-operative length of stay. Stroke was defined as any transient ischemic attack or permanent neurologic deficit; myocardial infarction was diagnosed by either troponins or echocardiogram along with clinical assessment; cardiac complications were composed of post-operative congestive heart failure, dysrhythmia and myocardial infarction; respiratory complications included pneumonia or reintubation. Primary and secondary outcomes were compared between three groups (1) TEVARs with prior TEVAR, (2) TEVAR with prior open thoracic repair, and (3) TEVAR without prior repair. Additionally, risk factors for 30-day mortality and spinal cord ischemia were determined for repairs of the proximal thoracic aorta (zones 0 3) and for repairs of the distal thoracic aorta (zones 4 6). Demographic variables were analyzed using 2 x 3 Chi-square tests for categorical variables and analysis of variance (ANOVA) tests for continuous variables. To identify independent predictors of outcome, multivariable logistic regression analyses were performed. Covariates were selected if a P value was <.05 on univariable analysis and after clinical judgment. All statistics were analyzed using SPSS Statistics Version 24.0 (Armonk, NY: IBM Corporation, 2016). Categorical variables were described as n and percentages; continuous variables were displayed as mean±standard deviation. Multivariable logistic regression results are shown as odds ratios (OR) with 95% confidence intervals. A two-tailed P value <.05 was considered statistically significant.
RESULTS: There were 4325 cases of TEVAR within the VQI registry with complete data for 30-day mortality and post-operative spinal cord ischemia, excluding all cases of prior abdominal aortic repair and current repairs that extend beyond aortic zone 6. Of the 4325 TEVARs, there were 168 TEVARs with prior TEVARs and 524 TEVARs with prior open thoracic repairs, 22 cases had prior TEVARs and open repairs equating to a total of 670 cases of TEVARs with prior repairs. Comparing baseline characteristics, TEVARs with prior repairs had higher rates of cerebrovascular disease, hypertension, congestive heart failure, lower ejection fraction, chronic obstructive pulmonary disease, connective tissue disease, cardiac interventions, peripheral
vascular interventions and bypasses, carotid interventions, operative indication as aneurysm, elective repair, pre-operative spinal drain use, older age, more intra-operative crystalloid, contrast volume, fluoroscopy time, and procedure time; but, lower diabetes, operative indication as trauma, and symptomatic presentation. On univariable analysis, there was no significant difference in 30-day mortality between TEVAR with prior TEVAR (9 of 145, 6.2%), TEVAR with prior open repair (22 of 524, 4.2%), and TEVAR without prior repair (229 of 3635, 6.3%), P=.18. There was also no significant difference in spinal cord ischemia between the three groups: TEVAR with prior TEVAR (5 of 147, 3.4%), TEVAR with prior open repair (17 of 531, 3.2%), and TEVAR without prior repair (136 of 3676, 3.7%), P=.85. Assessment of secondary endpoints showed no significant difference in post-operative retreatment between TEVAR with prior TEVAR (6.9%), TEVAR with prior open repair (12.0%), TEVAR without prior repair (12.0%), P=.17; stroke between TEVAR with prior TEVAR (1.2%), TEVAR with prior open repair (3.6%), TEVAR without prior repair (4.1%); cardiac complications between TEVAR with prior TEVAR (6.8%), TEVAR with prior open repair (8.8%), TEVAR without prior repair (10.6%), P=.17; and pulmonary complications between TEVAR with prior TEVAR (5.5%), TEVAR with prior open repair (9.2%), TEVAR without prior repair (10.7%), P=.08. However, TEVAR with prior repair averaged a shorter post-operative hospital length of stay compared to TEVAR without prior repair: TEVAR with prior TEVAR averaged 9.1±31.5 days, TEVAR with prior open repair averaged 7.2±7.4 days, and TEVAR without prior repair averaged 9.8±23.4 days, P=.04. Multivariable analyses are displayed in Table 1. Risk factors for 30-day mortality related to proximal repairs included older age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.02 1.05, P<.01), diabetes (OR 1.93, 95% CI 1.19 3.15, P<.01), non-elective repair (OR 2.17, 95% CI 1.32 3.57, P<.01), estimated blood loss (OR 1.00, 95% CI 1.00 1.00, P=.02), pre-operation hemoglobin (OR .91, 95% CI .82 1.00, P=.05) and total procedure time (OR 1.01, 95% CI 1.00 1.00, P<.01). Of proximal repairs, only TEVARs with prior repairs were associated with a perioperative survival benefit (OR .50, 95% CI .26 .95, P=.03). For distal repairs, 30-day mortality was associated with dialysis-dependence (OR 9.00, 95% CI 2.30 35.86, P<.01) and estimated blood loss (OR 1.00, 95% CI 1.00 1.00, P=.01). Variables predictive of spinal cord ischemia after proximal repair were: hypertension (OR 2.35, 95% CI 1.19 4.65, P=.01), total procedure time (OR 1.00, 95% CI 1.00 1.00, P<.01), and volume of crystalloid used intra-operation (OR 1.00, 95% CI 1.00 1.00, P=.01). Spinal cord ischemia after distal repair was predicted by dialysis-dependence (OR 6.60, 95% CI 1.05 41.38, P=.04) and ejection fraction <30% (OR 35.59, 95% CI 1.73 731.40, P=.02).
CONCLUSIONS: TEVAR after prior endovascular or open repair of the thoracic aorta is not associated with increased 30-day mortality or post-operative spinal cord ischemia. TEVAR after prior repair does not increase post-operative morbidity related to cardiac, stroke, or pulmonary complications, and may even shorten hospital length of stay. Notably, proximal TEVAR after prior repair may be associated with improved survival compared to proximal TEVAR without prior repair. Patients with prior thoracic aortic repair, whether endovascular or open, are not at higher risk for post-operative complications following TEVAR.
| Table 1: Multivariable Logistic Regression Analyses for 30-Day Mortality and Spinal Cord Ischemia Following TEVAR of the Proximal and Distal Thoracic Aorta | ||||
| Factors Predictive of 30-Day Mortality Following TEVAR of the Proximal Thoracic Aorta | ||||
| Covariates | Odds Ratio | 95% Confidence Intervals | P value | |
| Lower | Upper | |||
| Non-Elective Repair Diabetes Age Total Procedure Time Estimated Blood Loss TEVAR with Prior Thoracic Repair Pre-op Hemoglobin | 2.17 1.93 1.03 1.01 1.00 .50 .91 | 1.32 - 3.57 1.19 - 3.15 1.02 - 1.05 1.00 - 1.00 1.00 - 1.00 .26 - .95 .82 - 1.00 | <.01 <.01 <.01 <.01 .02 .03 .05 | |
| Factors Predictive of 30-Day Mortality Following TEVAR of the Distal Thoracic Aorta | ||||
| Dialysis-Dependent Estimated Blood Loss | 9.00 1.00 | 2.30 - 35.86 1.00 - 1.00 | <.01 .01 | |
| Factors Predictive of Spinal Cord Ischemia Following TEVAR of the Proximal Thoracic Aorta | ||||
| Total Procedure Time Hypertension Volume of Crystalloid Intra-op | 1.00 2.35 1.00 | 1.00 - 1.00 1.19 - 4.65 1.00 - 1.00 | <.01 .01 .01 | |
| Factors Predictive of Spinal Cord Ischemia Following TEVAR of the Distal Thoracic Aorta | ||||
| Ejection Fraction <30% Dialysis-Dependent | 35.59 6.60 | 1.73 - 731.40 1.05 - 41.38 | .02 .04 | |
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