Hemostatic alterations associated with supraceliac aortic cross-clamping.

PURPOSE: The causative role of consumptive coagulopathy in the development of bleeding complications after supraceliac (SC) aortic cross-clamping (AXC) has been challenged by recent reports that ascribe this coagulopathy to primary fibrinolysis. This theory is made on the basis of evidence that tissue plasminogen activator (t-PA) antigen (Ag) levels increase after SC AXC. However, t-PA Ag levels reflect both active and inactive (bound to serum t-PA inhibitors) forms of serum t-PA, and elevations confirm the presence of fibrinolysis only in conjunction with an increase in t-PA activity. METHODS: To investigate the etiology of this coagulopathy, we submitted eight pigs to SC AXC and six pigs to infrarenal (IR) AXC for 30 minutes. Blood was drawn from the portal vein, the hepatic vein, and the carotid artery before AXC, just before unclamping, and 5, 30, and 60 minutes after unclamping. Prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen (FBG), platelets (PLT), thrombin-antithrombin complexes (TAT), t-PA Ag, t-PA activity, plasminogen activator inhibitor-1 (PAI-1), and alpha2-antiplasmin (AP) activities were measured. Statistical analysis was performed by using repeated measures analysis of variance and t tests RESULTS: The PT did not differ between the two groups at any point. After unclamping, in the SC group there was a drop in PLT levels (P =.005), a decrease in FBG levels (P <.001), and a trend toward PTT prolongation (P =.06) compared with baseline. In contrast, there were no changes in PTT, PLT levels, or FBG levels in the IR group. TAT, a serum marker of thrombin generation, increased with SC AXC (P =.04), remained elevated 5 minutes after unclamping (P =.08), and returned to normal 30 minutes after unclamping. In contrast, TAT levels did not change in the IR control group. In the SC AXC group, the TAT levels did not differ between the three test sites at any time. SC AXC was associated with an increase in t-PA Ag just before unclamping (P <.001) and 5 minutes after unclamping (P =.002), but IR AXC was not. t-PA activity levels decreased in both experimental groups 30 and 60 minutes after unclamping. Levels of alpha2-AP activity decreased to a similar degree in both groups after unclamping when compared with baseline CONCLUSION: Thirty minutes of SC AXC results in intravascular thrombosis that cannot be localized to the ischemic visceral circulation. This intravascular thrombosis is associated with consumption of clotting factors. Thirty minutes of SC AXC causes an activation of fibrinolytic pathways that does not result in a hyperfibrinolytic state. An increase in t-PA Ag without a rise in t-PA activity does not represent true fibrinolysis, but rather an increase in the bound, inactive forms of serum t-PA. Both IR and SC AXC result in decreased fibrinolytic activity ("fibrinolytic shutdown") after release of the aortic clamp.     

Visceral lipid peroxidation occurs at reperfusion after supraceliac aortic cross-clamping

Purpose: Recently, we have reported that lipid peroxidation specific to oxygen free radical – mediated injury increased immediately after reperfusion of human liver allografts. However, in the human liver transplantation setting it was impossible to disassociate the contributions to lipid peroxidation caused by the warm and cold ischemic phases from those caused by reperfusion. Therefore we now have studied lipid peroxidation at reperfusion after supraceliac aortic cross-clamping in patients with normal livers.Methods: Ethane, a noninvasive biomarker of lipid peroxidation, was measured in exhaled breath of patients before and during cross-clamping of the thoracic aorta and at sequential time intervals after visceral reperfusion.Results: Approximately a two-fold transient increase in the ethane level was observed at around 15 minutes after reperfusion in those patients whose aortas were cross-clamped for more than 18 minutes.Conclusions: These results indicate that free radical–mediated lipid peroxidation occurs at reperfusion of warm ischemic viscera in the clinical setting of aortic repair. This observation supports the hypothesis that substantial lipid peroxidation occurs when tissues are subjected to cold or warm ischemia followed by reperfusion. (J VASC SURG 1994;19:473-7.)     

Analysis of coagulation changes associated with supraceliac aortic crossclamping using thromboelastography

INTRODUCTION: The etiology of the coagulation changes seen with supraceliac (SC) aortic crossclamping (AXC) remains controversial; both primary fibrinolysis and clotting factor consumption have been implicated. The cause of these changes was investigated with thromboelastography (TEG), a test that measures the viscoelastic properties of thrombus to dynamically assess coagulation and fibrinolysis. METHODS: Eight pigs underwent SC AXC for 30 min; 5 pigs undergoing 30 min of infrarenal (IR) aortic clamping served as controls. Blood was drawn before AXC, before unclamping, and 5 and 60 min after unclamping. Thromboelastography and standard coagulation tests [prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and platelet count] were performed. Measured TEG parameters included fibrinolytic index (a measure of fibrinolysis), r value (a reflection of intrinsic coagulation cascade activity), and the alpha angle and K values (measures of the speed of solid clot formation). Repeated measures ANOVA and t test were used for statistical analysis. RESULTS: There was no difference in the fibrinolytic index at any time point between the two groups. Increased activity of the intrinsic coagulation cascade during SC clamping was reflected by a lower R value just before unclamping (12.6 +/- 3.0 vs 20.0 +/- 3.0, P = 0.048) compared to IR AXC. Decreased speed of solid clot formation was noted 5 min after unclamping in the SC group but not the IR group [as defined by an increased K value (ANOVA, P = 0.010) and a decreased alpha angle value (ANOVA, P = 0.005)]. Fibrinogen levels were lower in the SC than in the IR group 5 (P = 0.013) and 60 min after unclamping (P = 0.02), but PT, PTT, and platelets did not differ between the groups at any time points. CONCLUSIONS: Thirty minutes of SC AXC does not result in fibrinolysis. There is increased clotting activity during SC clamping followed by decreased speed of clot formation and decreased fibrinogen levels after unclamping. These changes are consistent with clotting factor consumption.     

Systemic and mesenteric hemodynamics, metabolism, and intestinal tonometry in a rat model of supraceliac aortic cross-clamping and declamping

OBJECTIVE: To describe systemic and mesenteric hemodynamics, metabolism, and intestinal tonometry in a rat model of supraceliac aortic cross-clamping and declamping. DESIGN: Prospective, randomized, experimental study. SETTING: University cardiovascular research laboratory. PARTICIPANTS: Twelve male anesthetized and ventilated Sprague-Dawley rats. INTERVENTION: Supraceliac aortic cross-clamping was performed for 30 minutes, followed by declamping and reperfusion for 180 minutes or sham clamping and sham declamping. MEASUREMENTS AND MAIN RESULTS: Mean arterial blood pressure; abdominal aortic, superior mesenteric, and carotid artery blood flow; intestinal mucosal tonometry; hemoglobin; lactate; and blood gases were measured before and after 30 minutes of aortic cross-clamping and 15, 30, 60, 120, and 180 minutes after declamping during reperfusion. Aortic cross-clamping induced an increase in mean arterial pressure (117+/-20 mm Hg to 147+/-12 mm Hg), an increase in right atrial hemoglobin saturation(66%+/-11% to 81%+/-6%), an increase in lactate levels (1.7+/-0.7 mmol/L to 4.3+/-1.3 mmol/L), and an increase in tonometric PCO2 (49.6+/-5.0 mm Hg to 75.6+/-8.6 mm Hg). Three hours of reperfusion after declamping resulted in significantly decreased mean arterial pressure (38+/-10 mm Hg); decreased aortic (101+/-12 mL/min/kg to 57+/-32 mL/min/kg), mesenteric (19+/-4 to 13+/-6 mL/min/kg), and carotid (12+/-4 mL/min/kg to 5+/-3 mL/min/ kg) blood flows; and elevated lactate levels (4.2+/-2.0 mmol/L). Tonometric PCO2 had normalized to baseline levels (51.9+/-3.8 mm Hg), but PCO2 gap was significantly higher than in sham clamped rats (17.9+/-7.8 mm Hg v. 7.0+/-2.6 mm Hg). CONCLUSIONS: Hemodynamic and metabolic effects of aortic cross-clamping and declamping known from large animal models are reproducible using a rat model. Intestinal tonometry indicated mesenteric ischemia during aortic cross-clamping, which was reversible to preclamp values within 30 minutes of reperfusion after declamping.     

Normothermic cardioplegia: is aortic cross-clamping still synonymous with myocardial ischemia?

The enthusiastic clinical reports on normothermic blood cardioplegia contrast with the paucity of data on the myocardial metabolic effects of this technique. The present study was therefore designed to assess whether normothermic blood cardioplegia really provides an aerobic environment during aortic cross-clamping. Thirty-one patients undergoing coronary (16 patients), valve (13 patients), and transplantation (2 patients) procedures were given continuous normothermic blood cardioplegia through the coronary sinus. Myocardial metabolism was assessed either immediately before aortic unclamping (16 patients) by collecting blood simultaneously from the cardioplegia infusion line and the aortic effluent or during reperfusion (15 patients) by collecting blood simultaneously from the radial artery and the coronary sinus. All samples were assayed for markers of anaerobiosis (blood gases, lactates), leukocyte activation (elastase), and lipid peroxidation (malondialdehyde, vitamin E). At the end of arrest, oxygen extraction was low, whereas the production of lactates was small, thereby suggesting the efficacy of normothermic blood cardioplegia in maintaining a predominantly aerobic metabolism. This was confirmed by postarrest data, as oxygen extraction measured immediately after cross-clamp removal was unchanged from prearrest values, whereas lactate metabolism yielded transient and limited production followed by prompt recovery of normal extraction patterns. There was no release of elastase from the myocardium, which suggests adequate protection of the coronary endothelium from ischemic injury and the related increase in leukocyte activation. Likewise, postarrest coronary sinus concentrations of malondialdehyde and vitamin E were identical to the respective arterial concentrations, thereby ruling out the occurrence of intramyocardial lipid peroxidation at the time of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Endotoxemia during supraceliac aortic crossclamping is associated with suppression of the monocyte CD14 mechanism: possible role of transforming growth factor-beta1

PURPOSE: Monocyte CD14 and its soluble form (sCD14) mediate the proinflammatory response to endotoxemia. The aim of this study was to measure the changes to these factors after major aortic surgery and the possible inhibitory role of transforming growth factor-beta(1) (TGF-beta(1)) during these procedures. METHODS: Twenty-four patients with supraceliac aortic crossclamping during thoracoabdominal aortic aneurysm (TAAA) repair and 12 patients with infrarenal aortic crossclamping as part of infrarenal aneurysm repair (AAA) were studied. Blood was collected at incision, aortic clamping, and reperfusion and at 1, 8, and 24 hours after reperfusion. Samples were assayed for endotoxin, peripheral blood monocyte CD14 expression, sCD14, tumor necrosis factor-alpha, and TGF-beta(1). RESULTS: Although there was significant endotoxemia on reperfusion in both groups of patients, peak plasma endotoxin levels were significantly higher in patients with TAAA (P =.001). Monocyte CD14 and plasma sCD14 were significantly decreased in patients with TAAA at reperfusion and 1 hour after reperfusion (P <.01, both points). In patients with AAA, a significant upregulation of CD14 was observed at 24 hours after reperfusion (P <.01), but no significant changes in sCD14 were observed. TNF-alpha showed no significant changes during the study period in both groups. In patients with TAAA, TGF-beta(1) showed significant elevation at all time points (P <.01); whereas in patients with AAA, TGF-beta(1) showed no significant changes. CONCLUSION: Splanchnic ischemia reperfusion in patients who undergo supraceliac aortic clamping is associated with peripheral blood monocyte CD14 suppression and significant elevation of TGF-beta(1). TGF-beta(1) may play an important role in modulating the immune response to endotoxemia during major aortic aneurysm surgery.     

Effects of halothane and isoflurane on transient renal dysfunction associated with infrarenal aortic cross-clamping.

Aortic cross-clamping for reconstructive aortic surgery is associated with impairment of renal function. Halothane or isoflurane was used to assess the influence of volatile anesthesia on renal hemodynamics during aortic surgery. Nineteen patients with normal preoperative creatinine clearances who were scheduled for reconstructive aortic surgery were randomly divided into two groups: halothane group (n = 9) and isoflurane group (n = 10). Induction of anesthesia consisted of midazolam, fentanyl, and pancuronium. Anesthesia was maintained with fentanyl and halothane or isoflurane in nitrous oxide and oxygen (50/50). Systemic hemodynamics were similar in both groups throughout surgery. Before aortic cross-clamping, effective renal plasma flow (ERPF) (131I-hippuran clearance) and glomerular filtration rate (GFR) (99Tc-DTPA clearance) were significantly lower in the halothane group (118.4 +/- 25.6 and 19.7 +/- 5.2 mL/min, respectively) than in the isoflurane group (253.4 +/- 51.5 and 44.9 +/- 8.4 mL/min) (P less than 0.05 for both). During cross-clamping, the renal variables were not markedly affected in either group and remained higher in the isoflurane-anesthetized patients (232.9 +/- 47.1 and 49.5 +/- 1.2 mL/min for ERPF and GFR, respectively) than in the halothane-anesthetized patients (132.4 +/- 31.6 and 14.8 +/- 3.7 mL/min, respectively) (P less than 0.05). After aortic unclamping, ERPF increased markedly in both groups (467.8 +/- 122 and 362.5 +/- 57.7 mL/min in the halothane and isoflurane groups, respectively), as did GFR (74.8 +/- 22 and 71.8 +/- 13.1 mL/min, respectively). These results suggest that anesthesia with halothane is associated with transient renal vasoconstriction during abdominal surgery. In contrast, aortic cross-clamping during isoflurane anesthesia was not associated with renal hemodynamic impairment.     

Pathophysiology of aortic cross-clamping and unclamping

Aortic surgery is associated with a high incidence of perioperative complications, affecting virtually every organ system. The development of these complications is influenced by several factors, including whether surgery was emergent or elective, the location and duration of aortic cross-clamping, and the presence of coexisting disease states. The occurrence of end-organ damage reflects two main processes which are set in motion by aortic cross-clamping. The haemodynamic response refers to the changes produced in preload, afterload, and myocardial contractility. The humoral response refers to the formation and release of a series of mediators that both reflect and cause an ischaemia–reperfusion injury process. A clear understanding of the pathophysiological mechanisms involved in these processes will aid the clinician in adopting a rational approach to the care of patients undergoing aortic surgery.     

Reduction of myocardial injury with verapamil before aortic cross-clamping

The effect of verapamil administered before aortic cross-clamping was assessed in 40 patients undergoing elective coronary artery bypass grafting. Myocardial protection consisted of cold blood potassium cardioplegia, topical ice slush, and moderate (28 degrees C) systemic hypothermia. Patients were randomly divided into two groups: group 1 (18 patients) received verapamil (0.1 mg/kg up to 10 mg) intravenously three to five minutes before aortic cross-clamping; group 2 (22 patients) did not (control). Myocardial injury was assessed by cumulative release of the cardiac-specific isoenzyme of creatine kinase (CK-MB) after release of the aortic cross-clamp. Release of CK-MB was significantly lower in the verapamil group (44.9 +/- 6.2 versus 72.2 +/- 9.0 IU at 24.5 hours, p = 0.005). Calculated total infarct size was also lower in the verapamil group (6.0 +/- 0.9 versus 8.9 +/- 1.0 g-Eq, p = 0.035). Individual CK-MB release curves showed either one or two peaks. The two-peak pattern was more frequent in control patients (18 of 21 control patients versus 6 of 18 verapamil patients, p = 0.001) and was associated with a larger infarct size. Atrioventricular pacing was not required in any verapamil patient, but was needed in 1 control patient. We conclude that verapamil administered before aortic cross-clamping protects against myocardial injury during coronary artery bypass grafting with no increase in the incidence of atrioventricular block.     

Coronary artery bypass surgery with intermittent aortic cross-clamping.

Despite the generally accepted use of cardioplegia for myocardial protection during cardiac revascularization and other operations, non-cardioplegic methods have been used by many surgeons throughout the world. We have prospectively studied 229 patients consecutively subjected to isolated coronary artery bypass surgery from March 1990 to February 1991 by a single surgeon who used intermittent aortic cross-clamping for construction of the distal anastomoses. The mean age of the patients was 58.9 +/- 8.9 years. One hundred and nine patients (47.6%) with unstable angina were subjected to urgent or emergent surgery and 129 (56.3%) had a previous myocardial infarction. The mean number of grafts per patient was 3.0. The ischaemic time per graft was 6.5 +/- 1.4 min. At least one internal mammary artery was used in 98% of the cases (1.4 internal mammary artery grafts/patient). Hospital mortality was 0.9% (two patients, in neither case related to the procedure). Only nine patients (3.9%) required inotropes and none needed intra-aortic counterpulsation. The analysis of serum enzymes specific of myocardial lesion showed a CPK-MB/CPK ratio of 10.5 +/- 10.2 after surgery, 6.4 +/- 6.6% at 24 h after surgery, and 6.9 +/- 2.6% by the 5th day. Only four patients (1.7%) had ECG criteria of myocardial infarction. These results were compared retrospectively with those of the 40 immediately preceding patients (December 1989 to February 1990), in whom crystalloid cardioplegia had been used. There were no differences between the two groups with regard to age, prevalence of unstable angina and of previous myocardial infarction, and technique used.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ischemic preconditioning in myocardial revascularization with intermittent aortic cross-clamping

BACKGROUND: This study tests the hypothesis that initial brief periods of ischemia can increase the protection obtained by intermittent aortic cross-clamping. METHODS: In the control group (n = 18), the procedure was performed under intermittent aortic cross-clamping at 32 degrees C. Patients in the preconditioned gorup (n = 17) received a stimulus of two 3-minute periods of cross-clamping followed by 2 minutes of reperfusion prior to standard operation. CKMB, troponin 1, adenosine, and lactate were obtained from the great cardiac vein at the onset of cardiopulmonary bypass (CPB), at the end of the first anastomosis, and at the end of CPB. RESULTS: CKMB and troponin I were slightly higher at the end of CPB in the control group, while there was no difference between adenosine and lactate levels. [table: see text]. CONCLUSION: There was no difference between groups in terms of myocardial protection.     

Role of supraceliac aortic bypass in visceral artery reconstruction.

Twelve patients underwent transabdominal, supraceliac aortomesenteric bypass for celiac and superior mesenteric artery occlusive disease. Nine patients had bypass for intestinal ischemia (five acute, four chronic), and one patient each had bypass for arcuate ligament syndrome, thoracoabdominal aneurysm, and an infected aortic stump "blowout." Three aortoceliac, 9 aortohepatic, and 10 aortosuperior mesenteric artery bypasses were performed. Prosthetic grafts were used for the bypasses in 11 of the 12 patients. One death occurred in a patient with preexisting hepatic necrosis and renal failure secondary to acute mesenteric ischemia. During a mean follow-up of 26 months, one graft thrombosis occurred and required revision for recurrent symptoms. Supraceliac aortomesenteric bypass appears to be a safe and effective procedure for visceral revascularization.     

Surgical correction of descending thoracic aortic aneurysms under simple aortic cross-clamping

Between June 1983 and December 1987, 52 patients underwent resection of a descending thoracic aortic aneurysm under simple aortic cross-clamping without the use of shunting or bypass techniques. The 30-day mortality rate was 11.5%; 4.8% for elective cases and 36.5% for patients operated on in emergency. Two patients (4%) had spinal cord injury. One patient had paraplegia, and the other had mild paraparesis but completely recovered. Both patients were operated on for ruptured aneurysms. Four patients (7.5%) had severe postoperative renal dysfunction that was strongly related to intraoperative hypotension. The cumulative proportional survival rate was 81% at 1 year and 66% at 2 years for the total group. 85% at 1 year and 72% at 2 years for the patients first seen with nonruptured aneurysms. Aneurysms of the descending thoracic aorta can be safely resected without the use of shunting or bypass techniques. Surgery definitely improves the outcome for these patients who have a poor prognosis if left untreated.     

Prevention of gastric mucosal lesions following aortic cross-clamping

Stress ulceration is frequently encountered after cardiovascular surgery. In this study of 32 male baboons, severe gastric ischaemia was used to produce gastric stress lesions. The occurrence of these lesions was reduced by allopurinol (P = 0.03) and completely prevented by the combination of allopurinol with superoxide dismutase (P = 0.004). A shorter ischaemic period also reduced the number of lesions (P = 0.02). Concurrent with the stress lesion formation, there was a fall in mucosal glutathione and oxidized glutathione levels (P less than 0.05).     

Results of supraceliac aortic clamping in the difficult elective resection of infrarenal abdominal aortic aneurysm

We have used clamping of the aorta above the celiac axis (SC) in 30 of 431 elective resections of infrainguinal abdominal aortic aneurysms (AAA) during the past five years as an alternative to a difficult aortic cuff dissection. The results of SC clamping in these 30 patients are compared with the results of 379 routine aneurysm resections with infrarenal (IR) clamping and 22 additional aneurysm resections where the clamp was placed immediately above the renal arteries. These difficult cuff dissections occurred in 12 patients with inflammatory AAA, in 11 patients with juxtarenal AAA, and in seven patients with recurrent or noninfected false AAA of the proximal cuff. Patients with ruptured or suprarenal aneurysms and those undergoing combined operation for a visceral ischemic syndrome and an aneurysm were excluded from this study. Patients with SC clamping had similar operative mortality rates, comparable renal function, and frequency of cardiac events as patients with IR clamping. Blood loss was slightly higher in the SC group (p = 0.07) and serum aspartate amino transferase (AST) levels were three times higher than in the IR group; however, this was of no clinical significance. In contrast, those 22 patients whose aortas were clamped immediately above the renal arteries (AR) had higher perioperative mortality rates (2% IR, 3% SC vs 32% AR) and a higher incidence of kidney failure requiring dialysis (1% IR, 3% SC vs 23% AR). The mean values of serum creatinine and blood urea nitrogen were also significantly higher in the AR group when compared with both the IR and the SC groups (IR: 25 and 1.5 mg/dl, respectively; SC: 27 and 1.8 mg/dl; AR: 41 and 3.5 mg/dl). The single most important risk factor accounting for the differences between clamping above the celiac artery and clamping above the renal arteries was the presence of atherosclerotic debris in the nonaneurysmal, juxtarenal aortic segment. Clamping the aorta with juxtarenal atherosclerosis caused either atheroembolization to kidneys, legs, and intestine or injury to the aorta, renal arteries, or both; it was the cause of morbidity in all five cases of kidney failure requiring dialysis and accounted for all seven of the deaths in the AR group. SC clamping does not add risk to the patient undergoing resection of an infrarenal AAA and is the preferred method of achieving proximal control of the infrarenal aorta when a a hazardous cuff dissection is likely.(ABSTRACT TRUNCATED AT 400 WORDS)     

Interleukin-10 appearance following thoraco-abdominal and abdominal aortic aneurysm repair is associated with the duration of visceral ischaemia.

OBJECTIVES: to evaluate the plasma IL-10 levels during elective operative repair of thoraco-abdominal and abdominal aortic aneurysm repair. To study whether IL-10 plasma levels are associated with the duration of cross-clamping (ischaemia) and clinical outcome. MATERIALS: fifteen consecutive patients undergoing surgery for TAAA and 10 consecutive patients undergoing surgical repair of AAA were included. METHODS: plasma concentrations of IL-10 were measured by ELISA technique. Clinical outcome of the TAAA patients was prospectively analysed. RESULTS: during aortic clamping IL-10 was produced in both populations. The plasma IL-10 peak (934+/-172 pg/ml) of the TAAA group was seen at 4 h after declamping and remained detectable after 48 h. The plasma IL-10 peak (212+/-32 pg/ml) of the AAA group was seen 30 min after declamping and fell to undetectable levels by 24 h. These data show that the peak IL-10 plasma levels in TAAA repair are significantly (p<0.05) higher compared to the peak IL-10 plasma levels as seen during AAA repair. A positive correlation was seen between cross-clamping and peak plasma IL-10 and organ dysfunction. CONCLUSIONS: IL-10 plasma concentrations appear higher, later and are longer detectable in patients undergoing TAAA. Correlations were seen with duration of cross-clamping and MSOD.     

Isolated myocardial revascularization with intermittent aortic cross-clamping: experience with 800 cases

BACKGROUND: We investigated the clinical outcome of elective and nonelective myocardial revascularization performed with intermittent aortic cross-clamping. METHODS: Prospective data on 800 consecutive patients (from May 1996 to July 2000), who underwent isolated myocardial revascularization with intermittent aortic cross-clamping, were analyzed. A subgroup analysis was performed on the elective (n = 520), urgent (n = 226), and emergency (n = 54) procedures. RESULTS: The elective group of patients had a mean age of 61.5 +/- 9.46 years, mean Parsonnet score of 5.23 +/- 5.1, and mean number of distal anastomoses of 3.22 +/- 1.04. The hospital mortality was 0.57%. The urgent group of patients had a mean age of 63.06 +/- 10.43 years, mean Parsonnet score of 6.73 +/- 6.22, and mean number of distal anastomoses of 3.21 +/- 1.04. The hospital mortality was 3.09%. The emergency group of patients had a mean age of 63.75 +/- 9.63 years, mean Parsonnet score of 11.24 +/- 11, and mean number of distal anastomoses of 2.87 +/- 0.86. Hospital mortality was 5.55%. Postoperative hospital stay was 7.11 +/- 5.47 days for the elective group, 7.59 +/- 5.07 days for the urgent group, and 7.40 +/- 4.01 days for the emergency group. CONCLUSIONS: Intermittent aortic cross-clamping is a safe technique both in elective and nonelective patients. The mortality and morbidity in the three subgroups analyzed reflects patients' distribution against Parsonnet score.