Postoperative Chylothorax After Thoracoabdominal Aortic Aneurysm Repair.

Chylothorax is a potentially deadly complication that can occur after thoracoabdominal aortic aneurysm (TAAA) repair. We describe our contemporary experience (2005-2014) with this complication, our efforts to identify perioperative variables associated with it, and our attempts to assess treatment outcomes. We reviewed the records of 1092 consecutive patients who underwent TAAA repair between 2005 and 2014. Standard bivariate analysis was used to test for between-group differences. Eleven patients (0.9%) developed postoperative chylothorax. Nonoperative management was used in 8 of these patients (73%); 1 patient died after a lengthy hospital stay (297 days). The other 3 patients required thoracotomy with direct ligation; 1 of these patients required a second operation. Patients who developed chylothorax appeared to be similar to other patients in age, sex, extent of aneurysm, and metabolic or cardiovascular comorbidities. Patients who developed postoperative chylothorax were more likely to require drainage of a pleural effusion (P = 0.005), tracheostomy (P = 0.02), and longer stays in the intensive care unit (median, 6 [2-24] days, P < 0.001) and the hospital (median, 35 [24-88] days, P = 0.001), and these patients were more likely to develop a graft infection (n = 2, P < 0.001). The extent of TAAA repair (Crawford I-IV), reoperation, and clamping proximal to the left subclavian artery were not significantly associated with postoperative chylothorax. Chylothorax after TAAA repair can often be managed nonoperatively. Development of postoperative chylothorax may lead to significant morbidity, longer hospitalization, and increased likelihood of graft infection.

Aortic root surgery with circulatory arrest: Predictors of prolonged postoperative hospital stay.

OBJECTIVE: Little is known about the outcomes of aortic root operations that involve inducing hypothermic circulatory arrest for relatively extensive proximal aortic surgery. We attempted to identify predictors of postoperative hospital length of stay (LOS) and factors that affect postoperative recovery. METHODS: During 2006-2014, 247 of 265 patients (93.2%) with disease extending into the aortic arch survived aortic root operations (206 elective, 41 urgent/emergent) in which hypothermic circulatory arrest with moderate hypothermia was used. Stepwise multivariate regression analysis was performed to identify predictors of LOS (as a continuous variable) and prolonged LOS (defined as LOS >9 days, the median for the cohort). By this definition, 111 patients (45%) had prolonged LOS and 136 (55%) did not. RESULTS: Preoperative factors that independently predicted longer LOS in the entire cohort included age (P = .0014), redo sternotomy (P = .0047), and intraoperative packed red blood cell (PRBC) transfusion (P = .0007). Redo sternotomy and intraoperative PRBC transfusion also predicted longer LOS in 3 subgroup analyses: one of elective cases, one from which total arch replacement procedures were excluded, and one limited to patients who were discharged home. Age predicted longer LOS in the non-total arch (hemiarch) replacement patients. Ventilator support >48 hours (P < .0001) was associated with longer LOS. Elective aortic valve-sparing root replacement predicted a shorter LOS than valve replacement in multivariate regression analysis (P = .028). CONCLUSIONS: In patients undergoing aortic root surgery with hypothermic circulatory arrest for disease extending into the aortic arch, reducing intraoperative PRBC transfusion except when absolutely necessary may reduce postoperative LOS and expedite recovery. Performing aortic valve-sparing root replacement, when feasible, may also reduce LOS.

Moderate hypothermia at warmer temperatures is safe in elective proximal and total arch surgery: Results in 665 patients.

OBJECTIVE: To evaluate adverse outcomes after elective aortic arch surgery performed at higher or lower temperatures (24.0°C-28.0°C vs 20.1°C-23.9°C) within the wide range of moderate hypothermia. METHODS: Over a 9-year period, a total of 665 patients underwent elective proximal (n = 479) or total (n = 186) arch replacement with moderate hypothermia and antegrade cerebral perfusion. Circulatory arrest was initiated at an actual temperature of 20.1°C to 23.9°C in the lower-temperature group (n = 334; 223 proximal, 111 total) and at 24.0°C to 28.0°C in the higher-temperature group (n = 331; 256 proximal, 75 total). Composite adverse outcome was defined as operative mortality or persistent neurologic event or persistent hemodialysis at discharge. Multivariate logistic regression analysis was used to model adverse outcome. In addition to the actual temperature, a new, balanced variable, "predicted temperature," was analyzed to eliminate surgeon bias. We used this variable in a propensity score-matching analysis to validate the multivariate analysis results. RESULTS: A composite adverse outcome occurred in 7.2% of cases. Operative mortality was 5.1%. The rate of postoperative persistent neurologic deficits was 2.4%. No significant differences were found between the lower- and higher-predicted temperature groups within the moderate hypothermia range in the propensity score-matching analysis. The higher-actual temperature group had a lower rate of ventilator support at >48 hours (P = .036) and less need for tracheostomy (P = .023). Packed red blood cell transfusion and previous coronary artery bypass independently predicted composite adverse outcome (P = .0053 and .0002, respectively), operative mortality (P = .0051 and .0041), and postoperative stroke (P = .045 and .048). Cardiopulmonary bypass time independently predicted composite outcome (P = .0005), operative mortality (P < .0001), ventilatory support for >48 hours (P < .0001), and renal dysfunction (P = .0005). CONCLUSIONS: In elective proximal or total arch surgery, higher temperatures (≥24.0°C-28.0°C) within the wide range of moderate hypothermia (20.1°C-28°C) are safe and, compared with colder temperatures, not associated with significantly different rates of composite and adverse outcomes.

The impact of temperature in aortic arch surgery patients receiving antegrade cerebral perfusion for >30 minutes: How relevant is it really?

OBJECTIVE: We examined the early outcomes and the long-term survival associated with different degrees of hypothermia in patients who received antegrade cerebral perfusion (ACP) for >30 minutes. METHODS: During a 10-year period, 544 consecutive patients underwent proximal and total aortic arch surgery and received ACP for >30 minutes and 1 of 3 levels of hypothermia: deep (14.1°C-20°C; n = 116 [21.3%]), low-moderate (20.1°C-23.9°C; n = 262 [48.2%]), and high-moderate (24°C-28°C; n = 166 [30.5%]). A variable called "predicted temperature" was used in propensity-score analysis. Multivariate analysis was done to evaluate the effect of actual temperature on outcomes. RESULTS: The operative mortality rate was 12.5% (n = 68) overall and was 15.5%, 11.8%, and 11.5% in the deep, low-moderate, and high-moderate hypothermia patients, respectively (P = .54). The persistent stroke rate was 6.6% overall and 12.2%, 4.6%, and 6.0% in these 3 groups, respectively (P = .024 on univariate analysis). On multivariate analysis, actual temperature was not associated with mortality, but lower temperatures predicted persistent stroke and reoperation for bleeding. In the propensity-matched subgroups, the patients with predicted deep hypothermia had (nonsignificantly) greater rates of persistent stroke (12.2% vs 4.9%; relative risk, 1.08; 95% CI, 0.87-1.15) and reoperation for bleeding (14.6% vs 2.4%; relative risk, 1.14; 95% CI, 0.87-1.15) than the patients with predicted moderate hypothermia. On long-term follow-up (mean duration, 5.12 years), 4- and 8-year survival rates were 62.3% and 55.7% in the deep hypothermia group and 75.4% and 74.2% in the moderate hypothermia group (P = .0015). CONCLUSIONS: In proximal and arch operations involving ACP for >30 minutes, greater actual temperatures were associated with less stroke and reoperation for bleeding. There were no significant differences among the predicted hypothermia levels, although a trend toward a higher rate of adverse events was noticed in the deep hypothermia group. Long-term survival was better in the moderate hypothermia group.

Moderate hypothermia ≥24 and ≤28°C with hypothermic circulatory arrest for proximal aortic operations in patients with previous cardiac surgery.

OBJECTIVES: To determine whether, in patients with previous cardiac operations, moderate hypothermia (between 24 and 28°C) for hypothermic circulatory arrest (HCA) during antegrade cerebral perfusion (ACP) is safe for use during surgery on the proximal aorta and transverse aortic arch. METHODS: Over a 7-year period, 118 patients underwent ascending aortic and hemiarch repair (n = 70; 59.3%), total arch replacement (n = 47; 39.8%) or ascending aortic replacement to treat porcelain aorta (n = 1; 0.9%). Simultaneous procedures included aortic root repair or replacement (n = 33; 28.0%) and coronary artery bypass grafting (n = 21; 17.8%). All patients had previously undergone cardiac operations via a median sternotomy. Eighteen patients (15.3%) had more than 1 previous sternotomy, and 24 patients (20.3%) required emergent/urgent operation. Median cardiopulmonary bypass, cardiac ischaemic, circulatory arrest and ACP times (min) were 136.0 [118-180 interquartile range (IQR)], 91.0 (68-119 IQR), 34.0 (21-59 IQR) and 33.5 (20-59 IQR), respectively. The median temperature when HCA was initiated was 24.2°C (24.1-24.8°C IQR). RESULTS: The operative mortality rate was 10.2% (n = 12). Six patients (5.1%) had a permanent stroke, and 16 patients (13.6%) had a composite adverse outcome (operative mortality and/or a permanent neurological event and/or permanent haemodialysis at discharge). Preoperative renal disease was significantly more prevalent (P= 0.020) and the median circulatory arrest time significantly longer (48.5 vs 33 min; P= 0.058) in patients with composite adverse outcomes. Multivariable analysis of the redo patients showed that age (P =0.025), preoperative renal disease (P =0.024) and ACP time (P =0.012) were independent risk factors for a new postoperative renal injury. CONCLUSIONS: Moderate hypothermia for HCA during ACP is being used with increasing frequency, but has not been thoroughly evaluated in patients undergoing cardiovascular reoperations. Our experience suggests that in patients with previous cardiac surgery who are undergoing hemiarch and total aortic arch operations, moderate hypothermia is safe and produces respectable results.