Interact CardioVasc Thorac Surg 2008;7:850-854. doi:10.1510/icvts.2008.182303
© 2008 European Association of Cardio-Thoracic Surgery
ESCVS article - Aortic and aneurysmal |
Impact of pre-existing conditions, age and the length of cardiopulmonary bypass on postoperative outcome after repair of the ascending aorta and aortic arch for aortic aneurysms and dissections
Jeffrey P. Schwartza,
Mamdouh Bakhosa,
Amit Patela,
Sally Botkina and
Siyamek Neragi-Miandoabb,*
a Department of Thoracic and Cardiovascular Surgery, Loyola University Chicago, Stritch School of Medicine, 2160 South First Ave., Building 110, Room 6243, Maywood, IL 60153, USA
b Department of Surgery, St Vincent Medical Center, New York Medical College, School of Medicine, 170 West 12th Street, New York City, NY 10011, USA
Received 21 April 2008;
received in revised form 9 June 2008;
accepted 11 June 2008
 Presented at the 55th International Congress of the European Society for Cardiovascular Surgery, St Petersburg, Russian Federation, May 11–14, 2006.
*Corresponding author. Tel.: +1 617 9352782.
E-mail address: Sneragi{at}yahoo.com (S. Neragi-Miandoab).
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Abstract
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Background: Repair of the ascending aorta and aortic arch carries a high morbidity and mortality, which can be complicated by the often emergent nature of the intervention. Methods: We retrospectively evaluated the morbidity, mortality, and long-term survival in 101 patients who underwent repair of ascending aorta and aortic arch. Depending on the urgency of the operation, the patients were categorized as elective (EL, n=82) or emergent (EM, n=19). Log-rank-list and SPS were used to evaluate the data. Results: The average age was 58±16 years. The aortic diameter was 5.5±1 cm in the EL group and 6.1±1.4 cm for EM group. The aortic dissection in EL and EM groups was 15% and 79%, respectively. The mean circulatory arrest time (n=32 patients) was 38±18.5 min. The overall 30-day mortality was 4%: 0% for the EL group and 26% for the EM group. The overall 6-month mortality was 8%: 3.7% and 26% in EL and EM groups, respectively. Overall CVA was 3%: 0% in the EL group and 15.7% in the EM group. The mean CPB time was 176±81 min. The prolonged CPB time correlated with increased need for blood transfusion. The LOS was 12±8 days and correlated with increasing age (95% CI 0.06860–0.2307, P=0.0004), with NYHA stage of patients at the time of surgery (95% confidence intervals, 1.328–4.202, P=0.0003), with left ventricular ejection fraction (95% CI 0.2357 to –0.003029, P=0.0442) and with postoperative atrial fibrillation (95% CI 0.1192–0.4745, P=0.0018). The average ICU stay was 123±145 h. A prolonged CPB time resulted in extended ICU stay (95% CI 0.3655–1.486, P=0.0014). Further, the length of ICU stay correlated with NYHA status (95% CI 19.98–73.42, P=0.0008), age (95% confidence intervals 0.01668–3.761, P=0.0477), urgency of surgery (95% CI 65.00–124.0, P<0.0001), and length of CPB time (95% CI 0.3655–1.486, P=0.0014). Conclusion: Emergent operations are associated with high morbidity and mortality. Pre-existing heart failure, advanced age, and prolonged cardiopulmonary bypass are associated with prolonged monitoring in the ICU.
Key Words: Aortic dissection; Ascending aorta; Aortic arch; Aortic aneurysm
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1. Introduction
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Surgical mortality for acute type-A aortic dissection in different series varies from 5% to 30% [1–3]. Adverse neurologic events remain the most serious complication. The incidence of neurologic complications varies from 1–10% [4–6]. Independent preoperative predictors of mortality include previous aortic valve replacement, acute dissection with hypotension, shock, tamponade, and preoperative limb ischemia [1]. Independent preoperative predictors of operative mortality include previous aortic valve replacement, emergent nature of the disease at the time of presentation, acute dissection with hypotension, shock, tamponade, and preoperative limb ischemia [1].
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2. Methods
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The design of the study is a retrospective review of existing data of patients at our institution. We identified 101 patients (71 male and 30 female) who underwent either elective or emergent repair of the aortic arch from January 2001 to April 2004. Twenty patients (20%) underwent aortic arch repair only, 12 patients (12%) had ascending aorta and aortic arch repair, and the remaining 69 patients (69%) had hemiarch repair (proximal to arch vessels). Depending on the urgency of surgery and the patients' condition at the time of surgery, the patients were categorized as elective or emergent groups; urgent cases were grouped with elective cases because they could wait 24 h for the surgery; salvage cases were grouped with emergent cases. It was necessary to take this group of patients to the operating room immediately. Table 1 shows the urgency criteria and Table 2 shows the patient's profile. Computed tomogram (CT), coronary angiogram, and echocardiogram were used to evaluate the diameter of the aorta, coronary status, and valve function. All elective patients and the majority of emergent patients had a preoperative echocardiogram to assess left ventricular function and valvular heart disease. All reported P-values are two-sided, and P-values <0.05 were considered indicative of statistical significance. The surgical technique for arch repair in our series has been described by our group [4] and many others. The repair of ascending aorta was performed in standard fashion as described in the literature.
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3. Results
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The average NYHA class was 2.1±1.4, the aortic root diameter was 5.6±1.1 cm, the diameter of the ascending aorta was 5.7±1 cm, the aortic arch was 5.0±1.6 cm, and the descending aorta was 6±1.4 cm. The descending aorta was affected only in patients with aortic arch involvement, however, the involvement of descending aorta was limited and a complete replacement of descending aorta was not necessary in any of our patients. Eleven patients had undergone aortic valve replacement (AVR) at some point in the past. Three patients had previous pacemaker implantation, 17 patients had paroxysmal atrial fibrillation, and 8 patients had a history of myocardial infarction. Eighty-five percent of patients (70 of 82 patients) in the EL group and 21% of patients (4 of 19 patients) in the EM group had an aortic aneurysm, while 14.6% (n=12) of EL patients and 79% (n=15) of EM patients had dissection. All patients with dissection had undergone arch repair.
Twenty patients underwent arch repair only while 12 patients had repair of the ascending aorta and the aortic arch; the remaining 69 patients had repair of the aortic root, the ascending aorta, and the hemiarch (proximal to arch vessels). Additional concomitant procedures included: aortic valve replacement (AVR) in 29 patients, aortic valve repair and aortoraphy in three patients, mitral valve replacement in six patients, and coronary artery bypass grafting in 23 patients.
The overall 30-day mortality was 4%: 0% for the EL group and 26% for the EM group; and the intraoperative mortality was 2%. The overall 6-month mortality was 8%: 3.7% and 26% in the EL and EM groups, respectively. The overall postoperative morbidity with at least one or two complications was 61%. The overall CVA was 3%: 0% in the EL group and 15.7% in the EM group. Of those three patients, one had severe global neurologic dysfunction, but he remained non-focal. All three patients with neurologic complications underwent arch repair.
The mean CPB time was 176±81 min; a prolonged CPB time correlated with increased need for blood transfusion (Fig. 1, 95% CI 0.002165–0.02130, P=0.017). The length of hospital stay (LOS) was 12±8 days and correlated with increasing age (95% CI 0.06860–0.2307, P=0.0004), NYHA stage of patients at the time of surgery (95% CI 1.328–4.202, P=0.0003), and left ventricular ejection fraction (Fig. 2, 95% CI –0.2357 to –0.003029, P=0.0442). The median length of ICU stay was 64 h (ranging between 10 and 746 h). The average ICU stay was 123±145 h. A prolonged CPB time resulted in an extended ICU stay (Fig. 3, 95% CI 0.3655–1.486, P=0.0014). The overall mean cross-clamp time was 120±52 min (95% CI –0.008606 to 0.02454, P=0.3373). A prolonged cross-clamping time did not prolong the need for intensive monitoring postoperatively (95% CI –0.2049 to 1.159, P=0.1673).
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Fig. 1. A prolonged cardiopulmonary bypass resulted in increased need for blood transfusion postoperatively (95% confidence interval 0.2875–0.6005, P<0.0001).
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Fig. 2. Patients with compromised left ventricular function had a prolonged hospital stay (95% confidence intervals –0.2357 to –0.003029, P=0.0442).
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Fig. 3. The need for closed monitoring in SICU correlated with the length of cardiopulmonary bypass time (95% confidence intervals 0.3655–1.486, P=0.0014).
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The length of ICU stay correlated with NYHA status (Fig. 4, 95% CI 19.98–73.42, P=0.0008), age (95% CI 0.01668–3.761, P=0.0477), urgency of surgery (Fig. 5, 95% CI 65.00–124.0, P<0.0001), and length of CPB time (Fig. 3, 95% CI 0.3655–1.486, P=0.0014). Thirty-two patients (32%) had circulatory arrest with a mean circulatory arrest time of 38±18.5 min, which did not correlate with the ICU stay of patients postoperatively (95% CI –2.366 to 5.662, P=0.4076).
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Fig. 4. Patients with an advanced NYHA stage had to be monitored in SICU for a longer period of time (95% confidence intervals 19.98–73.42, P=0.0008).
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Fig. 5. The length of stay in SICU was a reflection of emergent nature and status of patients at the time of presentation (95% confidence intervals, 65.00–124.0, P<0.0001).
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Elevated pulmonary artery pressure seemed to prolong the need for ICU monitoring; however, it was not statistically significant (95% CI –0.1896 to 6.282, P=0.0642). The pulmonary artery pressure did not correlate with prolonged intubation time (95% CI –0.7940 to 3.449, P=0.2158).
Postoperative bleeding requiring re-exploration occurred in 5% of patients; the average need for blood transfusion was 8 U, 51% of patients (n=50) had platelet transfusion, 53% (n=53) had fresh frozen plasma (FFP) transfusion, and 30% (n=30) had transfusion of cryoprecipitate. The need for postoperative blood transfusion correlated with the duration of CPB time (95% CI 0.2875–0.6005 P=0.0001).
The overall cardiovascular complications were 45%; 16% of patients in the EL group and 10.5% of patients in the EM group had pericardial effusion with tamponade-like physiology requiring pericardiocentesis prior to discharge from the hospital. Recurrent pleural effusion was observed in 9% (n=9) of patients. Pneumothorax requiring chest tube placement was seen in 3% of patients (n=3). Vocal cord paralysis occurred in 2% of patients (n=2).
Renal insufficiency occurred in 8% of patients (6% and 16% for the EL and EM groups, respectively), and renal failure requiring dialysis occurred in 3% (2.5% in EL and 5.3% in EM group). One patient had left calf compartment syndrome requiring fasciotomy, one patient developed pancreatitis, and one patient was readmitted on POD 10 for acute gastrointestinal bleed. Table 3 demonstrates the postoperative complications in EL and EM groups.
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4. Discussion
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Emergency repair of thoracal aortic aneurysm remains a formidable operation with high morbidity and mortality [7]. Patient selection plays an important role in determining surgical outcomes in patients with acute type A aortic dissection and can contribute to a better management of these patients [1]. Patients with emergent presentation, acute pain, rupture, or complicated acute dissection at the time of presentation have a poor outcome. Further, the surgical morbidity and mortality after aortic arch replacement seems to be higher if the aorta has already dissected [8]. The overall mortality for repair of the ascending aorta has been reported to be 5–10% [9–12].
In a series of 290 patients, Trimarchi et al. [1] categorized the patients as high risk (hemodynamically unstable) or low risk (stable patients). The overall in-hospital mortality was 25.1%: 31.4% for the high risk group compared to 16.7% for the low risk group. In a series of 70 patients, Long et al. [13] reported an operative mortality of up to 50% for emergency patients compared to 9% in stable patients. Univariate analysis suggested that preoperative shock, tamponade, and neurologic deficit are associated with high mortality [13]. In a series of 108 patients, Apaydin et al. [14] reported a hospital mortality of 25%; a high percentage of patients (34%) in their series had acute dissection requiring emergent intervention. The impact of emergent status at the time of presentation on morbidity and mortality was confirmed by Yoshimoto et al. [12] and Santini et al. [15].
In a series of 920 patients, Estrera et al. [11] reported a perioperative mortality of 10.8%. The authors reported that by multivariate analyses, renal function, cardiopulmonary bypass time, and emergency status were significant independent risk factors for mortality [11]. We categorized our patients into elective (EL) and emergent (EM) groups based on their symptoms and the urgency of surgical intervention at the time of presentation. The emergent nature of the disease was associated with poor survival. The 30-day mortality for emergency patients was 26%, while none of the elective patients expired within this time frame. Our data are in concert with Estrera et al. [11] data regarding the significance of CPB length and the impact of emergent status of patients at presentation on outcome. Narayan et al. [16] reported a mortality of 5.9% for elective re-operations vs. 25% in emergency re-operations. In their series of 29 patients, all had previous cardiac surgery, and the authors concluded that a previous cardiac surgery is not a contraindication for repair of the aorta. In our series, only 11% of patients had previous heart surgery, which might contribute to the low mortality in our series.
Ehrlich et al. [10] evaluated the predictors of adverse outcome (AO) after replacement of the ascending aorta in 167 patients with a mean hypothermic circulatory arrest (HCA) time of 30 min. Adverse outcome occurred in 30.5% (51/167) of patients overall. Multivariate analysis revealed that the only significant independent preoperative predictor of AO was hemodynamic instability [10]. Spielvogel et al. [17] reported a series of 150 consecutive patients who underwent aortic arch replacement. The authors reported very good results with low AO in only 8.7% of patients (7 hospital deaths and 6 permanent strokes) [17]. Our group previously published a series of 32 patients (also included in this paper) who underwent complete aortic arch repair. Our results were in concert with Spiegelvogel's results [4]. The overall 30-day mortality in this series was 4%; intraoperative mortality was 2%. The overall 6-month mortality was 8%, and the overall actuarial survival at six months was 96.3% for elective patients and 74% for emergency patients.
The incidence of neurologic complications has been reported to range from 2% to 10% [9, 17–20]. The overall cerebrovascular accident (CVA) in our series was 3%: 0% in the EL group and 15.8% in the EM group (two patients suffered a stroke, one patient had severe global neurologic dysfunction). The low incidence of neurologic events in our series might be a result of low circulatory arrest time (38±18.5 min) and low bypass time (176±81 min). Furthermore, only 32 patients in our series underwent arch replacement, which carries a high risk of neurologic complications.
The duration of hypothermic circulatory arrest is a predictor of transient neurologic dysfunction, but not stroke [14]. Coselli et al. [21] reported that the neurologic deficit correlates with the length of circulatory arrest. A period of 40 min or less of circulatory arrest is rarely associated with neurologic complications. Some authors reported increased incidence of neurologic adverse events when the circulatory arrest lasted longer than 50–60 min [20]. In Ehrlich et al. series of 167 patients, transient neurological dysfunction occurred in 16.4% of the patients. Risk factors included advanced age (>60 years) and coronary artery disease [10]. The mean circulatory arrest time in our series (38±18.5 min, n=32) did not correlate with the ICU stay of patients postoperatively (95% CI –2.366 to 5.662, P=0.4076).
Postoperative atrial fibrillation seems to be one of the most common complications of this procedure [20]. Matsuura et al. [22] reported a postoperative new onset of atrial fibrillation in 52.7% of 483 patients after undergoing total aortic arch repair, which resulted in prolonged postoperative hospital stay in the intensive care unit. The overall incidence of cardiovascular complications in our series was 45%; atrial fibrillation/flutter occurred in 27%, ventricular fibrillation in 2%, atrioventricular block in 6%, and pericardial effusion requiring pericardiocentesis in 15% of patients. The length of postoperative hospital stay and intensive care unit stay was longer in patients with postoperative atrial fibrillation (P=0.0045).
The average ICU stay was 123±145 h. A prolonged CPB time resulted in an extended ICU stay (123±145 h, P=0.0014) (Fig. 3), while a prolonged cross-clamping time (P=0.167) did not prolong the need for intensive monitoring postoperatively. The length of ICU stay correlated with NYHA status (P=0.0008), left ventricular ejection fraction (Fig. 2, P=0.0442), age (P=0.0477), urgency of surgery (Fig. 5, P<0.0001), and length of CPB time (P=0.0014). Closed monitoring was required with prolonged CPB time; however, pre-existing conditions had a more significant impact on the postoperative course, which requireed prolonged ICU monitoring.
Profound hypothermia causes coagulopathy, but the length of the procedure and the prolonged cardiopulmonary bypass time are the primary determinants of postoperative bleeding. In a series of 116 patients undergoing aortic surgery with profoundly or moderately hypothermic cardiopulmonary bypass, Harrington et al. [23] reported that prolonged CPB time was the only predictor of postoperative hemorrhage and exploration for bleeding. Other authors reported postoperative bleeding of 2.5–10% after aortic arch replacement [17, 24]. The exact amount of postoperative bleeding was not documented in our series, however, the need for postoperative blood transfusion correlated with the duration of CPB time (P=0.0001).
Postoperative respiratory failure (defined as ventilation >72 h, need for reintubation, or trachostomy) is a serious complication that leads to increased mortality after major operations in the chest cavity [17, 20]. The overall respiratory complications in our patients (intubated for more than 72 h but <7 days) occurred in 17% of EL patients and 47% of EM patients; postoperative pneumonia was diagnosed in 9%; 7.4% and 16% in the EL and EM groups, respectively.
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5. Conclusion
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Repair of the ascending aorta and aortic arch can be performed with acceptable morbidity and mortality; however, emergent operations are associated with high morbidity and mortality. Patients with compromised cardiac function, advanced age, and prolonged cardiopulmonary bypass time require prolonged monitoring in the intensive care unit. An echocardiogram shortly before discharge is recommended to assess the size of the pericardial effusion followed by pericardiocentesis if tamponade like physiology is present.
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Abstract
1. Introduction
