NEW YORK – Delayed selective repair and the use of thoracic endovascular aortic surgery rather than urgent open procedures reduce mortality from blunt thoracic aortic injury, an analysis of 15 years of data has shown.
Thoracic aortic injury remains a leading cause of death following blunt trauma, second only to death from head injury. It is estimated that prehospital mortality is as high as 85%, said Dr. Anthony L. Estrera, a cardiothoracic and vascular surgeon at the University of Texas Medical School at Houston.
Dr. Anthony L. Estrera
Between January 1997 and January 2012, more than 17,000 patients were entered into the University of Texas-Houston Trauma Center Registry. Of those, 327 (0.4%) were diagnosed with blunt thoracic aortic injury (BTAI). The overall mortality rate for these patients was 41% (135/327). Thirty-five percent (n = 114) died within 4 hours of admission, Dr. Estrera said at Aortic Symposium 2012.
Before 1999, open-clamp repair was performed in 20% of all operations. Distal aortic perfusion (DAP) with open repair was introduced in 1999, delayed selective repair in 2002, and thoracic endovascular aortic repair (TEVAR) in 2005. Delayed selective repair involves delaying intervention for traumatic aortic injury when other injuries, such as head injury or severe abdominal injuries, require immediate attention, Dr. Estrera explained in an interview.
During the 15-year study period, 56% (n = 184) underwent either open surgery (total bypass, 4%; open repair with visceral perfusion [open DAP], 42%; or open clamp, 16%), or TEVAR (39%).
Of those 184 patients, 27 (15%) died. The TEVAR mortality rate (4%) was significantly lower than that of the open-repair groups (open clamp, 31%; open DAP, 14%; total bypass, 57%, P less than .03). In fact, since 2005, TEVAR has been used for 71% of procedures, and the average annual mortality rate has dropped from 25%-40% to 0%-15%.
Urgent repair was associated with significantly more deaths than was delayed selective repair (22% [26/120] vs. 1.6% [1/64], P less than .02). Adjusting for injury severity score and calendar time, the investigators found that delayed repair resulted in a greater than 10-fold reduction in mortality compared with immediate open intervention (odds ratio, 0.07; P less than .02).
No deaths were noted in 4 of the last 6 years. Among open procedures, significantly better outcomes were seen with open DAP vs. open clamp (P less than .02) and with DAP vs. total bypass (P less than .05).
"We found that delayed selective repair was beneficial with open repair but not in conjunction with TEVAR. The benefit of delayed selective repair is likely related to allowing the patient time to recover from the initial traumatic insult before proceeding with another major insult, the open repair," Dr. Estrera said. "Delayed selective repair is considered for patients who present with severe head injury, infection (burn, sepsis, contaminated wounds), or multisystem trauma."
While surgical technique made a difference in mortality, no significant differences were found between groups with respect to complications. The three cases of paraplegia, which occurred only in the open-clamp group, did not have outcomes that were significantly different from outcomes in other groups. There was one case of stroke in the open-clamp group and two cases in the TEVAR group, but this also was not statistically significant.
As for durability of repair, Dr. Estrera noted that patients in the open-repair group have been followed for 6.2-15 years, and all-cause mortality data indicate that "if they survive beyond that first admission, they do pretty well." The available follow-up data for TEVAR is much shorter: up to 6 years with a mean of 2.5 years. "We don’t know what the long-term durability of these stent-grafts will be, especially in younger patients who may live for another 50 years," he said.
One problem with obtaining long-term survival data is that patients who survive BTAI can be very difficult to follow up. In their experience, Dr. Estrera said, compliance with TEVAR follow-up was only 32%, which may be attributed in part to patients being relatively young (median age, 32 years) and male (70%).
Dr. Estrera’s group is seeking ways to improve the diagnosis of BTAI. In a recent study, the diagnostic utility of computed tomography angiography (CTA) – the most commonly used screening test for BTAI – was compared with intravascular ultrasound (IVUS) or angiography (J. Vasc. Surg. 2011;53:608-14). Equivocal results were found to be more common with CTA images than with either IVUS or angiography (27% vs. 2.5% and 5%, respectively; overall P = .0002). Compared with angiography, IVUS changed the diagnosis in 13% of cases, identifying injuries in 11% and ruling them out in 2%. Angiography was found to be 38% as sensitive and 89% as specific as IVUS.