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Nardi et al. Postoperative malperfusion in aortic dissection

Table 3: Predictors of in-hospital mortality Table 4: Predictors of postoperative malperfusion syndrome
Univariate Multivariate Univariate Multivariate
Variable Variable
P value OR 95% CI P value P value P value
Age ≥ 75 years 0.0078 1.1 1.0-1.1 0.0004
Renal PM < 0.0001 53.5 4.0-721.3 0.0027 Preoperative LVEF < 40% 0.007 0.04
Any preoperative < 0.0001 0.14
malperfusion syndromes Preoperative dialysis 0.03 NS
Preoperative cerebral 0.0345 0.62 Entry tear distal to the
preoperative malperfusion ascending aorta - proximal 0.04 NS
BMI > 30 0.0131 0.40 aortic arch
CABG 0.0353 0.15 LVEF: left ventricular ejection fraction; OR: odds ratio; CI:
CPB time 0.0008 0.12 confidence interval; NS: not significant
Aortic cross clamp time 0.0225 0.90
PM: postoperative malperfusion; BMI: body mass index; CABG: a LVEF value of 40% or less was the only independent
coronary artery bypass grafting; CPB: cardiopulmonary bypass; predictor of having a PM (P < 0.05) [Table 4].
OR:odds ratio; CI: confidence interval
Preoperative cerebral malperfusion was an
clinical characteristics of the cohort, stratified according
to the presence or absence of PM, were reported in independent predictor of cerebral PM [odds ratio (OR):
Table 1. 2.5, 95% confidence interval (CI): 1.0-6.1, P < 0.05].
Interestingly, a LVEF of less than 40% was only a
Intraoperative mortality occurred in 14 (6.5%) patients found to be a significant risk factor for renal PM when
and in-hospital mortality after surgery occurred in 48 using univariate analysis techniques (P < 0.0001).
(22.4%) patients. Using univariate analyses, significant Finally, an entry tear distal to the ascending aorta or to
risk factors for in-hospital mortality included: being at the proximal aortic arch requiring extensive repair and
least 75 years old, having a body mass index of more longer surgical time was a risk factor of mesenteric PM
than 30 kg/m , having preoperative overall or cerebral (P < 0.05, using univariate analyses).
2
malperfusion, having longer cardiopulmonary bypass
and aortic clamping times, needing concomitant Follow-up results
coronary artery bypass grafting (CABG), having renal The mean duration of follow-up was 42.4 ± 23.7
PM requiring continuous veno-venous hemofiltration, months (median 46 months). All patients were followed
and have postoperative mechanical ventilation for up until the end of the study period. One- and 5-year
to 24 h. The multivariate analyses revealed that being overall survival rates were 96.0 ± 1.6% and 90.8 ±
75 years old or older at the time of surgery (P < 0.001) 3.2%, respectively [Figure 1]. Cox regression analyses
and having renal PM (P < 0.01) were independent identified that independent predictors of long-term
predictors of in-hospital mortality [Table 3]. survival were: being at least 75 years old at the time
of surgery (OR: 3.7, 95% CI: 0.9-14.0, P = 0.05) and
Fifty-five (25.7%) patients showed clinical symptoms having a renal PM (OR: 28.6, 95% CI: 1.8-462.0, P
and/or imaging evidence of PM. In 42 cases, only 1 = 0.01) [Table 5]. When the survival probability was
organ system was affected, including: the brain in 13 dichotomized by age, (with a threshold of 75 years old
(6.5%) patients, the kidneys in 22 (10.3%) patients, at the time of the surgery), the 5-year survival rates
and the viscera in 7 (3.3%) patients. In a subgroup were 91.6 ± 3.5% for patients < 75 years old and 65.1
of PM patients with just 1 affected organ system, the ± 19.5% for patients ≥ 75 years old (P < 0.05). The
mortality rate was 40.5%. In 11 patients, PM occurred 5-year survival rate for patients without PM was 93.9
in 2 organ systems (5 in the brain and kidneys, 3 in ± 3.4% vs. 78.6 ± 7.8% for those affected by PM (Log-
the brain and viscera, 3 in the kidneys and viscera); rank test, P < 0.01).
the mortality rate in this subgroup was 63.6%. PM
involving all 3 organ systems occurred in just 2 cases DISCUSSION
and both patients died. Overall, the in-hospital mortality
rate in patients affected by any PM was 47.3% (26/55) Despite improvements in medical management and
vs. 22.6% (36/159) in patients without PM (P < 0.001). surgical techniques, acute type A aortic dissections still
Univariate analyses identified that the risk factors have high mortality and morbidity rates. [1,2] The IRAD
for any PM included: having a preoperative LVEF of revealed that the expected mortality rate for patients
less than 40% (P < 0.01), having preoperative renal undergoing AAAD surgery ranges from 20% to 30%. [9]
dysfunction (P < 0.05) and having an entry tear distal Our cardiac surgery division has extensive experience
to the ascending aorta or to the proximal aortic arch (P in the treatment of acute aortic dissection; we observed
< 0.05). Multivariate analyses determined that having an in-hospital mortality rate of 29%. Several studies
80 Vessel Plus ¦ Volume 1 ¦ June 27, 2017