Katherine H. Simpson

Reoperations on the total aortic arch in 119 patients: short- and mid-term outcomes, focusing on composite adverse outcomes and survival analysis.

OBJECTIVES To determine the preoperative and perioperative risk factors that significantly predict adverse outcomes after total arch replacement in patients with previous proximal aortic surgery and to analyze patient survival. METHODS We performed univariate analysis and logistic regression on data extracted from a prospectively maintained database for 119 patients who had undergone total arch operations during a 7.5-year period. All patients had undergone previous proximal aortic surgery. The adverse outcome was defined as a single composite endpoint comprising operative mortality, permanent neurologic deficit, and renal failure necessitating permanent hemodialysis. RESULTS The incidence of the composite endpoint was 13.5% (16 of 119 patients). The univariate predictors were preoperative pulmonary disease (P = .010), cardiac ischemia time (P = .032), and cardiopulmonary bypass (CPB) time (P = .073). On multivariate analysis, the following were predictors of the composite endpoint: preoperative pulmonary disease (P = .036), CPB time (P = .039), concomitant coronary artery bypass (P = .0057), previous aortic valve replacement (P = .027), and previous thoracoabdominal aortic aneurysm surgery (P = .057). Multivariate analysis showed that the CPB time predicted mortality (P = .0044), and previous thoracoabdominal aortic aneurysm surgery predicted stroke (P = .034). The overall survival was 85.3% during a median follow-up of 4.76 years (95% confidence interval, 4.2-5.1). CONCLUSIONS Aortic arch reoperations, although technically demanding, can produce acceptable results. Preoperative pulmonary disease, CPB time, and concomitant coronary artery bypass predicted an adverse outcome. The CPB time predicted mortality, and previous thoracoabdominal aortic surgery predicted stroke.

Unilateral Versus Bilateral Cerebral Perfusion for Acute Type A Aortic Dissection

BACKGROUND Antegrade cerebral perfusion (ACP) is standard treatment for complex aortic pathology and includes both unilateral (u-ACP) and bilateral (b-ACP) techniques. Focusing on proximal acute aortic dissection, we investigated the clinical effect of u-ACP versus b-ACP. METHODS From January 2005 to May 2013, 157 consecutive patients presented with acute type A aortic dissection. Antegrade cerebral perfusion was used in 153 patients (97.4%). Ninety patients (58.8%) received u-ACP, and 63 (41.2%) received b-ACP. No retrograde cerebral perfusion was used. The target systemic hypothermia temperature during ACP was 22° to 24°C. The mean ACP, cardiopulmonary bypass, and cardiac ischemia times were 34.6 ± 18.0, 125.6 ± 48.0, and 92.6 ± 34.1 minutes, respectively. RESULTS The p values from logistic regression models indicated that in both groups combined, the ACP, cardiopulmonary bypass, and cardiac ischemia times predicted hospital mortality (p = 0.035, p = 0.0033, and p = 0.035, respectively) but not stroke. The operative mortality was 13.3% (n = 12) with u-ACP and 12.7% (n = 8) with b-ACP (p = 0.91). Of the survivors, 13 of 88 u-ACP patients (14.8%) and 8 of 62 b-ACP patients (12.9%) had a postoperative stroke (p = 0.75). A circulatory arrest time of >30 minutes was associated with stroke (p = 0.031). Temporary neurologic dysfunction was present in 10 u-ACP (11.4%) and 5 b-ACP (8.2%) patients (p = 0.53). Postoperative renal failure occurred in 10 u-ACP (11.4%) and 10 b-ACP patients (16.1%) (p = 0.40). Antegrade stent delivery in the descending thoracic aorta did not affect the ACP, cardiac ischemia, circulatory arrest, or cardiopulmonary bypass times. CONCLUSIONS As one of the largest single-center studies of the efficacy of u-ACP and b-ACP in patients with type A aortic dissection, operative mortality, stroke, temporary neurologic dysfunction, and renal failure rates were similar in both. In this intrinsically complex disease, survival is the most important outcome; u-ACP may provide cardiac surgeons with valuable technical simplicity during challenging procedures, and b-ACP may be justified for circulatory arrest times of more than 30 minutes.

Hemiarch and Total Arch Surgery in Patients With Previous Repair of Acute Type I Aortic Dissection

BACKGROUND We examined our contemporary experience with hemiarch and total arch replacement in patients with previous acute type I aortic dissection. METHODS Over an 8.5-year period, 137 consecutive patients (median age 58 years, interquartile range, 50 to 67) underwent hemiarch or total transverse aortic arch replacement a median of 7.7 years (range, 67 days to 32 years; interquartile range, 2.8 to 12.3 years) after previous acute type I aortic dissection repair. Interventions involving only the aortic root, aortic valve, descending aorta, or thoracoabdominal aorta were excluded. Multivariate analysis of 20 potential preoperative and intraoperative risk factors was performed to examine early death, neurologic deficit, composite endpoint (operative death, permanent neurologic deficit, or hemodialysis at discharge), and long-term mortality. RESULTS Total arch replacement was performed in 103 patients (75.2%), hemiarch replacement in 34 (24.8%), and elephant trunk procedures in 77 (56.2%). Thirty-one repairs (22.6%) were emergent or urgent. There were 16 operative deaths (11.7%), 4 permanent strokes (3.6%), and 21 (15.3%) instances of the composite endpoint. In the multivariate analysis, congestive heart failure and cardiopulmonary bypass time independently predicted operative mortality (p = 0.0027, p = 0.018). Emergency operation approached significance for stroke (p = 0.088). Predictors of long-term mortality (during a median follow-up period of 5.1 years, 95% confidence interval: 4.4 to 5.8) were female sex (p = 0.0036), congestive heart failure (p = 0.0045), and circulatory arrest time (p = 0.0013); preoperative pulmonary disease approached significance (p = 0.074). Five-year survival was 73.2%. CONCLUSIONS In patients with previous acute type I aortic dissection repair, hemiarch and total arch operations have respectable morbidity and survival rates. Congestive heart failure predicts operative death, long-term mortality, and our adverse event endpoint. Cardiopulmonary bypass time predicts operative mortality, and female sex and circulatory arrest time predict long-term mortality.

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.

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.

Elective primary aortic root replacement with and without hemiarch repair in patients with no previous cardiac surgery

Objective: Excellent outcomes have been established for elective aortic root replacement (ARR). It is less clear whether extending the repair into the proximal aortic arch with hypothermic circulatory arrest increases risk. We examined the early outcomes of elective, primary ARR, with and without hemiarch replacement, in patients without previous cardiac surgery. Methods: Over a 4‐year period, 140 non‐redo patients (median age, 54 years) underwent elective, primary ARR for root aneurysms; 119 patients (85%) had hemiarch replacement, and 21 (15%) had only ascending aortic replacement. Valve‐sparing ARR was performed in 41 cases (29.3%) and valve‐replacing ARR in 99 (70.7%). Moderate hypothermic circulatory arrest and antegrade cerebral perfusion were used in 118 (99%) hemiarch repairs. Results: There were no operative deaths or permanent strokes. Complications included temporary renal dialysis (n = 1; 4.8%), transient neurologic deficit (n = 2; 9.5%), and tracheostomy (n = 2; 9.5%) after ascending aortic repair and bleeding requiring reoperation (n = 4; 3.4%), pericardial effusion requiring drainage (n = 9; 7.6%), and tracheostomy (n = 2; 1.7%) after hemiarch replacement. No stroke was observed in the hemiarch group (P = .022; univariate analysis). The extent of the repair into the proximal arch did not appear to be associated with any adverse effect. Conclusions: In non‐redo patients, elective primary ARR has excellent early outcomes, regardless of whether repair extends into the proximal arch. Additional elective hemiarch replacement with moderate hypothermic circulatory arrest and antegrade cerebral perfusion has a low risk of neurologic complications and should be performed if necessary. Long‐term data are needed to compare the rates of reintervention in the aortic arch in patients with or without proximal arch replacement.