Is laparotomy for mesenteric ischemia futile after aortic dissection?

N. J. Goel¹, J. Anil¹, S. Mendes¹, J. J. Kelly¹, S. Mosbahi², M. Berezowski¹, N. D. Desai^1
1University of Pennsylvania, Philadelphia, Pennsylvania ²University of Pennsylvania Health System, Philadelphia, Pennsylvania

Purpose: Gut necrosis from persistent gut ischemia after aortic dissection will progress to sepsis and death without emergent laparotomy. However, the signs of gut necrosis are common in patients suffering non-survivable multisystem failure. No study has yet examined when and whether laparotomy offers a chance for meaningful survival after aortic catastrophe.

Methods: Patients with acute Type A or Type B aortic dissection complicated by gut ischemia were queried from a single institution from 2006 to 2022. A total of 145 such patients were identified including 29 that underwent laparotomy, all of whom had long-term follow-up of at least two years. All patients who underwent laparotomy had a compelling clinical indication including peritonitis, GI bleeding, imaging findings of gut ischemia or lactic acidosis. Detailed clinical characteristics, including laboratory values prior to laparotomy, were studied and compared among survivors and non-survivors. Odds ratios based on univariate analysis are presented (Table 1). Outcomes related to subsequent hospital course and post-discharge outcomes including discharge disposition, readmissions, reinterventions, and long-term survival were also queried. Post-discharge outcomes of laparotomy survivors were compared to all survivors of aortic dissection with gut malperfusion and all survivors of Type A aortic dissections (Figure 1).

Results: Among laparotomy patients, 45% (13/29) survived to discharge compared to 71% (103/145) of all gut malperfusion patients. No comorbidities were associated with survival after laparotomy, including age. Dissection factors not associated with survival after laparotomy included Penn Class, lower extremity malperfusion, and Type A vs Type B dissection. Lactate and arterial pH were both very strongly associated with survival after laparotomy. Among survivors and non-survivors, mean lactate immediately prior to laparotomy was 6.3 mmol/L vs 13.4 mmol/L (p=0.024) and pH was 7.39 vs 7.20 (p < 0.001). In particular, lactate over 8 (OR [95%CI] = 16.5 [2.0-192], p=0.003) and pH under 7.30 (OR [95%CI] = 14.4 [1.87-128], p=0.003) were both extremely strong predictors of mortality. Survival to discharge after laparotomy for patients with both severe lactatemia and severe acidosis (defined above) was only 9% (1/11) compared to 75% (12/16) for all other patients. Renal function did not predict survival, and one third of patients requiring dialysis before laparotomy survived. Among thirteen laparotomy survivors, five were discharged home directly. Their survival to one year was 77%. There was no significant difference in long-term survival on pairwise comparison among laparotomy survivors, all gut malperfusion survivors, and all Type A survivors (Figure 1).

Conclusion: A select but substantial population of patients with persistent gut ischemia after aortic dissection can survive with laparotomy. The degree of lactic acidosis at time of laparotomy is by far the most important factor influencing survival and is an extremely strong predictor. Likelihood of survival for a patient with lactate over 8 and pH under 7.30 at time of laparotomy is less than 10%, whereas for all other patients it is ~75%. Those patients that do survive a laparotomy have a prolonged course but ultimately achieve long-term outcomes that are not dissimilar from all other survivors of complicated aortic dissection.

Identify the source of the funding for this research project: Support by an NIH T32 training grant awarded to lead author