Early repair is the standard of care for patients with type A aortic dissection, but the presence of malperfusion rather than the timing of surgery may be a major determinant in patient survival both in the hospital and in the long term, according to an analysis of patients with acute type A aortic dissection over a 17-year period at the University of Bristol (England).
“Malperfusion at presentation rather than the timing of intervention is the major risk factor for death in both the short term and long term in patients undergoing surgical repair of type A aortic dissection,” Pradeep Narayan, FRCS, and his colleagues said in reporting their findings in the July issue of the Journal of Thoracic and Cardiovascular Surgery (154:81-6). Nonetheless, Dr. Narayan and his colleagues acknowledged that early operation prevents the development of malperfusion and is the best option for restoring normal perfusion for patients who already have malperfusion.
Their study analyzed results from two different groups of patients who had surgery for repair of acute type A aortic dissection over a 17-year period: 72 in the early surgery group that had operative repair within 12 hours of symptom onset; and 80 in the late-surgery group that had the operation 12 hours or more after symptoms first appeared. A total of 205 patients underwent surgical repair for acute type A aortic dissection in that period, but only 152 cases had recorded the timing of surgery from onset of symptoms. The median time between arrival at the center and surgery was 3 hours.
Dr. Narayan and his coauthors reported that 39% (60) of the 152 patients had malperfusion. Organ malperfusion was actually more common in the early surgery group, although the difference was not significant: 48.6% vs. 31.3% in the late-surgery group (P = .29). Early mortality was also similar between the two groups: 19.4% in the early surgery group and 13.8% in the late surgery group (P = .8). In terms of late survival, the study found no difference between the two groups.
Dr. Narayan and his coauthors reported that malperfusion and concomitant coronary artery bypass grafting were independent predictors of survival, with hazard ratios of 2.65 (P = .01) and 3.03 (P = .03), respectively. As a nonlinear variable, time to surgery showed an inverse relationship with late mortality (HR, 0.51; P = .26), but as a linear variable when adjusted for other covariates, including malperfusion, it did not affect survival (HR, 1.01; P = .09).
“The main finding of the present study is that almost 40% of patients undergoing repair of type A aortic dissection had evidence of malperfusion,” Dr. Narayan and his coauthors said. “The second important finding is that the presence of malperfusion was associated with significantly increased risk of death in both the short-term and long-term follow-up.” While a delayed operation was associated with a reduced risk of death, it was not significant when accounting for malperfusion.
Dr. Narayan and his coauthors acknowledged limitations of their study, the most important of which was the including of different types of malperfusion as a single variable. Also, the small sample size may explain the lack of statistically significant differences between the two groups.
Dr. Narayan and his coauthors had no financial relationships to disclose.