Temporary neurological dysfunction after deep hypothermic circulatory arrest: a clinical marker of long-term functional deficit

Progress in ascending and aortic arch surgery: minimally invasive surgery, blood conservation, and neurological deficit prevention

BACKGROUND

Herein are described recent developments in aortic surgery techniques and the improved results.

METHODS

Of 403 ascending and aortic arch operations, 68 patients underwent minimally invasive aortic surgery including 23 for aortic dissection, 5 for Marfan syndrome, 29 reoperations, and 39 with hypothermic arrest. Blood conservation methods were used in 187 of the 403 patients (46.5%). Aortic valve procedures were used in 267 (66.2%), including 51 (12.7%) valve-preserving operations. A protocol for stroke and neurocognitive deficit prevention was used in an attempt to prevent neurologic deficits. Data were prospectively collected and included new neurocognitive events either by formal testing (n = 35) or by informal questioning.

RESULTS

Stroke occurred in 2.0% (8 of 403); clinical gross neurocognitive deficits in 2.5% (10 of 403) with a 98% 30-day survival. For those patients undergoing the minimally invasive operation 1 hospital death occurred (98.5% survival). Homologous operative transfusions were required in only 12% of blood conservation patients (23 of 187) and their postoperative intubation time, intensive care unit (ICU) stay, and hospital stay were significantly shorter (p < 0.04).

CONCLUSIONS

Minimally invasive surgery is particularly useful for reoperations. The blood conservation methods appear to be beneficial and the number of neurologic deficits is low with the current protocol.

Replacement of the ascending and transverse aortic arch: determinants of long-term survival

BACKGROUND

Although little has been published on the natural history of aneurysms of the ascending aorta and aortic arch, long-term prognosis of untreated aneurysms is generally poor. We reviewed our 10-year experience in the repair of the ascending aorta and aortic arch to evaluate long-term outcome.

METHODS

Between January 1991 and May 2001, we repaired 423 aneurysms of the ascending aorta or aortic arch using profound hypothermic circulatory arrest. Median age was 65 years. Retrograde cerebral perfusion (RCP) was used in 357 cases. Mean pump and RCP times were 139 and 33.9 minutes, respectively. Survival was ascertained by direct patient contact or by searching the social security death index. Survival was analyzed by Kaplan-Meier stratified analysis and by multivariate Cox regression.

RESULTS

Overall actuarial survival was 72% at 5 years and 71% at 10 years after surgery. Univariate analysis identified increasing age (p < 0.0001), chronic obstructive pulmonary disease (p < 0.014), concurrent unoperated aneurysm (p < 0.005), arch involvement (p < 0.042), pump time (p < 0.0004), concurrent aortic valve replacement (p < 0.009), and postoperative renal failure (p < 0.0002) as factors that negatively influenced survival. Multivariate analysis identified increasing age (p < 0.0001) and pump time (p < 0.0001). RCP did not have a significant independent effect on the long-term survival.

CONCLUSIONS

Our experience indicates that repair of the ascending aorta and aortic arch can be accomplished with good long-term survival.

Surgical treatment of acute type A dissection: is rupture a risk factor?

BACKGROUND

The purpose of this study was to evaluate the significance of aortic rupture on clinical outcome in patients after aortic repair for acute type A dissection.

METHODS

One hundred and twenty patients underwent aortic operations with resection of the intimal tear and open distal anastomosis. Median age was 60 years (range 16 to 87); 78 were male. Thirty-six patients had only ascending aortic replacement, 82 had hemiarch repair, and 2 had the entire arch replaced. Retrograde cerebral perfusion was utilized in 66 patients (53%). Rupture defined as free blood in the pericardial space was present in 60 patients (50%). Univariate and multivariate analyses were performed to assess the risk factors for mortality and neurologic dysfunction.

RESULTS

Overall hospital mortality rate was 24.2% +/- 4.0% (+/- 70% confidence level) but did not differ between patients with aortic rupture or without (p = 0.83). The incidence of permanent neurologic dysfunction was 9.4% overall, 10.5% with rupture and 8.3% without rupture (p = 0.75). Multivariate analysis revealed absence of retrograde cerebral perfusion and any postoperative complication as statistically significant indicators for in-hospital mortality (p < 0.05). Overall 1- and 5-year survival was 85.3% and 33.7%; among discharged patients, survival in the nonruptured group was 89% and 37%, versus 81% and 31% in the ruptured group (p = 0.01).

CONCLUSIONS

Aortic rupture at the time of surgery does not increase the risk of hospital mortality or permanent neurologic complications in patients with acute type A dissections. However, aortic rupture at the time of surgery does influence long-term survival.

Prolonged mild hypothermia after experimental hypothermic circulatory arrest in a chronic porcine model

OBJECTIVES

We sought to evaluate the potential efficacy of prolonged mild hypothermia after hypothermic circulatory arrest.

METHODS

Twenty pigs, after a 75-minute period of hypothermic circulatory arrest, were randomly assigned to be rewarmed to 37 degrees C (normothermia group) or to 32 degrees C and kept at that temperature for 14 hours from the start of rewarming (hypothermia group).

RESULTS

The 7-day survival was 30% in the hypothermia group and 70% in the normothermia group (P =.08). The hypothermia group had poorer postoperative behavioral scores than the normothermia group. Prolonged hypothermia was associated with lower oxygen extraction and consumption rates and higher mixed venous oxygen saturation levels during the first hours after hypothermic circulatory arrest. Decreased cardiac index, lower pH, and higher partial pressure of carbon dioxide were observed in the hypothermia group. There was a trend for beneficial effect of prolonged hypothermia in terms of lower brain lactate levels until the 4-hour interval and of intracranial pressure until the 10-hour interval. Postoperatively, total leukocyte and neutrophil counts were lower, and creatine kinase BB was significantly increased in the hypothermia group. At extubation, the hypothermia group had higher oxygen extraction rates and lower brain tissue oxygen tension.

CONCLUSIONS

A 14-hour period of mild hypothermia after 75-minute hypothermic circulatory arrest seems to be associated with poor outcome. However, the results of this study suggest that mild hypothermia may preserve its efficacy when it is used for no longer than 4 hours, but the potentials of a shorter period of postoperative mild hypothermia still require further investigation.

Effect of deep hypothermia on cerebral hemodynamics during selective cerebral perfusion with systemic circulatory arrest

OBJECTIVE

We studied the effect of deep hypothermia on cerebral hemodynamics during selective cerebral perfusion with systemic circulatory arrest.

METHODS

Ten anesthesized pigs were placed on cardiopulmonary bypass and cooled to a rectal temperature of 22 degrees C (n = 5) or 15 degrees C (n = 5). During selective cerebral perfusion, the descending aorta was clamped and perfusion of the lower body was discontinued. As the pump flow was changed, we monitored the perfusion pressure, local cerebral blood flow, and local cerebral oxygenation using laser Doppler flowmetry and near-infrared spectroscopy. We also measured the free flow of the left internal thoracic artery during selective cerebral perfusion.

RESULTS

Perfusion pressure and local cerebral blood flow decreased as the pump flow decreased. Oxygenated and deoxygenated hemoglobin in cerebral tissue remained unchanged at a perfusion flow of 10 ml/kg/min, whereas oxygenated hemoglobin decreased and deoxygenated hemoglobin increased progressively and reciprocally as the pump flow decreased. The pump flow for maintaining perfusion pressure above 35 mmHg with stabilized local cerebral oxygenation was significantly higher at 15 degrees C than at 22 degrees C. The internal thoracic artery free flow was higher at 15 degrees C than at 22 degrees C.

CONCLUSIONS

Selective hypothermic cerebral perfusion with systemic circulatory arrest produces an extracranial shunt through the internal thoracic artery, especially under deep hypothermia. Our data suggests that selective cerebral perfusion during deep hypothermia is best managed by perfusion pressure control rather than by flow control.

Transient advanced mental impairment: an underappreciated morbidity after aortic surgery

OBJECTIVES

To determine the incidence, risk factors, and associated morbidity of transient advanced mental impairment (TAMI) after aortic surgery.

METHODS

We retrospectively studied the charts of 188 consecutive patients undergoing elective aortic reconstruction during a recent 6-year period at a university hospital. All patients were lucid on admission and nonintubated at the time of evaluation at least 2 days after operation. TAMI was defined as disorientation or confusion on 2 or more postoperative days. Preoperative, intraoperative, and postoperative clinical variables were examined statistically for associations with TAMI.

RESULTS

Fifty-three patients (28%) had development of TAMI 3.9 plus minus 2.8 days after operation. Stepwise logistic regression analysis selected the following independent predictors for TAMI: age >65 years (odds ratio [OR], 7.9; 95% confidence interval [CI], 2.7 to 23.7), American Society of Anesthesiology physical status classification >3 (OR, 2.8; 95% CI, 1.3 to 5.9), diabetes mellitus (OR, 3.4; 95% CI, 1.2 to 9.8), old myocardial infarction (OR, 2.4; 95% CI, 1.1 to 5.3), and hypertension (OR, 2.3; 95% CI, 1.0 to 5.3). Alcohol consumption was not significantly associated with TAMI. In the postoperative period, patients with TAMI were more likely to have hypoxia (P <.001), a need for reintubation (P <.001), pneumonia (P <.001), congestive heart failure (P =.003), and kidney failure (P =.05). In addition, patients with TAMI had a longer duration of endotracheal intubation (3.7 plus minus 7.8 vs 0.6 plus minus 1.2 days, P <.001), stay in the intensive care unit (8.9 plus minus 9 vs 3.9 plus minus 2 days, P <.001), and postoperative hospital stay (14.8 plus minus 11 vs 9.2 plus minus 5 days, P <.001) than patients without TAMI. Twenty (38%) patients with TAMI were discharged to intermediate-care facilities, compared with 11 (8%) patients without TAMI (P <.001). Postoperative variables conferring the largest relative risks for development of TAMI included oxygen saturation less than 92% (5.4), the need for reintubation (3.3), congestive heart failure (3.3), and pneumonia (3.2). TAMI, conversely, conferred the largest relative risks for development of postoperative congestive heart failure (15.3), the need for reintubation (9.3), pneumonia (7.1), and the need for ICU readmission (3.8).

CONCLUSIONS

These data show that TAMI is prevalent among patients undergoing aortic reconstruction and is associated with dramatically increased morbidity and postoperative hospitalization rates.

Cerebral Protection During Surgery of the Aortic Arch

The most significant challenge in surgical repair of the aortic arch (transverse thoracic aorta) is to protect the brain from ischemic injury. During the portion of the procedure when the brachiocephalic vessels are at tached to a graft, there is an obligatory interruption in the normal path of circulation to the brain. Various strategies are used to overcome the potential for brain injury during discontinuity between the aorta and the cerebral circulation. These include deep hypothermic circulatory arrest, retrograde cerebral perfusion, and selective anterograde cerebral perfusion. Pharmaco logic adjuncts to these procedures are also used to further enhance brain protection. This review ad dresses the relative merits of these techniques as means of cerebral protection.

Involvement of apoptosis in neurological injury after hypothermic circulatory arrest: a new target for therapeutic intervention?

BACKGROUND

This study was undertaken to evaluate the role of apoptosis in neurological injury after hypothermic circulatory arrest (HCA).

METHODS

Twenty-one pigs (27 to 31 kg) underwent 90 minutes of HCA at 20 degrees C and were electively sacrificed at 6, 24, 48, and 72 hours, and at 7, 10, and 12 days after HCA, and compared with unoperated controls. In addition, 3 animals that had HCA at 10 degrees C, and 3 treated with cyclosporine A (CsA) in conjunction with HCA at 20 degrees C, were examined 72 hours after HCA. After selective perfusion and cryopreservation, all brains were examined to visualize apoptotic DNA fragmentation and chromatin condensation on the same cryosection of the hippocampus: fluorescent in situ end labeling (ISEL) was combined with staining with a nucleic acid-binding cyanine dye (YOYO).

RESULTS

In addition to apoptosis, which was seen at a significantly higher level (p = 0.05) after HCA than in controls, two other characteristic degenerative morphological cell types (not seen in controls) were characterized after HCA. Cell death began 6 hours after HCA and reached its peak at 72 hours, but continued for at least 7 days. Compared with the standard protocol at 20 degrees C, HCA at 10 degrees C and CsA treatment both significantly reduced overall cell death after HCA, but not apoptosis.

CONCLUSIONS

The data establish that significant neuronal apoptosis occurs as a consequence of HCA, but at 20 degrees C, other pathways of cell death, probably including necrosis, predominate. Although preliminary results suggest that the neuroprotective effects of lower temperature and of CsA are not a consequence of blockade of apoptotic pathways, inhibition of apoptosis nevertheless seems promising as a strategy to protect the brain from the subtle neurological injury that is associated with prolonged HCA at clinically relevant temperatures.

Safety and efficacy of hypothermic cardiopulmonary bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta

BACKGROUND

Hypothermic cardiopulmonary bypass with circulatory arrest is an important adjunct for operations on the distal aortic arch and the descending thoracic and thoracoabdominal aorta. Its safety and efficacy compared with other techniques (eg, simple aortic clamping, partial cardiopulmonary bypass, and regional hypothermia) are not clearly established.

METHODS

One hundred sixty-one patients (ranging from 20 to 83 years old) with descending thoracic or thoracoabdominal aortic disease had resection and graft replacement of the involved aortic segments using hypothermic cardiopulmonary bypass usually with intervals of circulatory arrest (mean interval, 38 minutes).

RESULTS

The 30-day mortality rate was 6.2% (10 patients). It was 41% (7 of 17) for patients having emergent operations (rupture or acute dissection) and 2.1% (3 of 144) for all other patients (p < 0.001). The 90-day mortality rate was 11.8% (19 patients). Paraplegia occurred in 4 and paraparesis in 1 of the 156 operative survivors whose lower limb function could be assessed postoperatively (3.2%). Among the 91 survivors with thoracoabdominal aortic disease, early paraplegia occurred in 1 of 33 patients with Crawford type I disease, 0 of 34 with type II disease, and 2 of 24 with type III disease. One patient (type II disease) had development of paraplegia on the tenth postoperative day. None of the 50 patients with aortic dissection experienced paralysis. Renal dialysis was required in 4 (2.5%) of the 157 operative survivors, prolonged inotropic support (> 48 hours) in 17 (11%), reoperation for bleeding in 8 (5%), mechanical ventilation (> 48 hours) in 31 (20%), and tracheostomy in 13 (8%). Three patients (1.9%) sustained a stroke.

CONCLUSIONS

Hypothermic cardiopulmonary bypass provides safe and substantial protection against paralysis and renal, cardiac, and visceral organ system failure that equals or exceeds that of other currently used techniques but without the need of other adjuncts.

Prospective randomized neurocognitive and S-100 study of hypothermic circulatory arrest, retrograde brain perfusion, and antegrade brain perfusion for aortic arch operations

BACKGROUND

To determine the optimal method of brain protection during deep hypothermic circulatory arrest (DHCA) for arch repair.

METHODS

Of 139 potential aortic arch repairs (denominator), we randomized 30 patients to either DHCA alone (n = 10), DHCA plus retrograde brain perfusion (RBP) (n = 10), or antegrade perfusion (ANTE) (n = 10); a further 5 coronary bypass (CAB) patients were controls. Fifty-one neurocognitive subscores were obtained for each patient at each of four intervals: preoperatively, 3 to 6 days postoperatively, 2 to 3 weeks postoperatively, and 6 months postoperatively. Intraoperative and postoperative S-100 blood levels and electroencephalograms were also obtained.

RESULTS

For the denominator, the 30-day and hospital survival rate was 97.8% (136 of 139) and the stroke rate 2.8% (4 of 139). For the randomized patients, the survival rate was 100% and no patient suffered a stroke or seizure. Circulatory arrest (CA) times were not different (DHCA: RBP:ANTE) for 11 total arch repairs (including 6 elephant trunk; mean, 41.4 minutes; standard deviation, 15). Hemiarch repairs (n = 17) were quickest with DHCA (mean 10.0 minutes; standard deviation, 3.6; p = 0.011) and longest with ANTE (mean 23.8 minutes; standard deviation, 10.28; p = 0.004). Of the patients, 96% had clinical neurocognitive impairment at 3 to 6 days, but by 2 to 3 weeks only 9% had a residual new deficit (1 DHCA, 1 RBP, 1 ANTE), and by 6 months these 3 patients had recovered. Comparison of postoperative mean scores showed the DHCA group did better than RBP patients in 5 of 7 significantly different (p < 0.05) scores and versus 9 of 9 ANTE patients. There were no S-100 level differences between CA groups, but levels were significantly higher versus the CAB controls, particularly at the end of bypass (p < 0.0001); however, these may have been influenced by other variables such as greater pump time, cardiotomy use, and postoperative autotransfusion. Circulatory arrest (p = 0.01) and pump time (p = 0.057) correlated with peak S-100 levels.

CONCLUSIONS

The results of hypothermic arrest have improved; however, there is no neurocognitive advantage with RBP or ANTE. Nevertheless, retrograde brain perfusion may, in a larger study, potentially reduce the risk of strokes related to embolic material. S-100 levels may be artificial. In patients with severe atheroma or high risk for embolic strokes, we use a combination of retrograde and antegrade perfusion on a selective basis.

Neurologic outcome after ascending aorta-aortic arch operations: effect of brain protection technique in high-risk patients

OBJECTIVE

We sought to assess the optimal strategy for avoiding neurologic injury after aortic operations requiring hypothermic circulatory arrest.

METHODS

All 717 patients who survived ascending aorta-aortic arch operations through a median sternotomy since 1986 were examined for factors influencing stroke. Temporary neurologic dysfunction was assessed in all patients who survived the operation without stroke since 1993. Multivariate analyses were carried out to determine independent risk factors for neurologic injury.

RESULTS

Independent risk factors for stroke were as follows: age greater than 60 years (P <.001; odds ratio, 4.5); emergency operation (P =.02; odds ratio, 2.2); new preoperative neurologic symptoms (P =.05; odds ratio, 2.9); presence of clot or atheroma (P <.001; odds ratio, 4.4); mitral valve replacement or other concomitant procedures (P =.055; odds ratio, = 3.7); and total cerebral protection time, defined as the sum of hypothermic circulatory arrest and any retrograde or antegrade cerebral perfusion (P =.001; odds ratio, 1.02/min). In 453 patients surviving operations without stroke after 1993, independent risk factors for temporary neurologic dysfunction included age (P <.001; odds ratio, 1.06/y), dissection (P =.001; odds ratio, 2.2), need for coronary artery bypass grafting (P =.006; odds ratio, 2.1) or other procedures (P =.023; odds ratio, 3.4), and total cerebral protection time (P <.001; odds ratio, 1.02/min). When all patients with total cerebral protection times between 40 and 80 minutes were examined, the method of cerebral protection did not influence the occurrence of stroke, but antegrade cerebral perfusion resulted in a significant reduction in incidence on temporary neurologic dysfunction (P =.05; odds ratio, 0.3).

CONCLUSIONS

The occurrence of stroke is principally determined by patient- and disease-related factors, but use of antegrade cerebral perfusion can significantly reduce the occurrence of temporary neurologic dysfunction.

Cyclosporine A as a potential neuroprotective agent: a study of prolonged hypothermic circulatory arrest in a chronic porcine model

OBJECTIVE

To assess whether Cyclosporine A (CsA) or cycloheximide (CHX) can reduce ischemia-induced neurological damage by blocking apoptotic pathways, we assessed their effects on cerebral recovery in a chronic animal model of hypothermic circulatory arrest (HCA).

METHODS

Twenty-eight pigs (28-33 kg) underwent 90 min of HCA at 20 degrees C. In this blinded study, animals were randomized to placebo (n=12), 5 mg/kg CsA (n=8), given intravenously before and subcutaneously for 7 days after HCA, or a single dose of 1 mg/kg CHX (n=8), given after weaning from cardiopulmonary bypass. Hemodynamics, intracranial pressure (ICP) and neurophysiological data (EEG, SSEP) were assessed for 3 h after HCA; early behavioral recovery was scored, and neurological/behavioral evaluation (9=normal) was carried out daily until elective sacrifice on postoperative day (POD) 7. Brains were selectively perfused and evaluated histopathologically for apoptosis.

RESULTS

Basic hemodynamic data revealed no differences between CsA or CHX and control groups. ICP was significantly lower throughout rewarming (P=0.009) and reperfusion (P=0.05) in the CsA group. EEG recovery 3 h after HCA was observed in four of eight CsA animals but in only 1 of 12 controls (P=0.11) and one of eight CHX animals; cortical SSEP recovery also seemed faster in CsA animals, but failed to reach significance. Some early recovery scores were significantly better in the CsA group, and daily behavioral scores were consistently and significantly higher in the CsA-treated animals from POD1 through POD4.

CONCLUSIONS

The data indicate that treatment with Cyclosporine A but not cycloheximide has a positive effect on cerebral recovery following HCA. Whether CsA results in inhibition of neuronal apoptosis, and/or inhibits release of cytokines and thereby reduces postischemic cerebral edema remains to be elucidated. The neuroprotective effect of CsA, if confirmed in further studies, would make its clinical application conceivable.

Results of aortic arch repair with hypothermic circulatory arrest and retrograde cerebral perfusion

BACKGROUND

Repair of aortic arch pathology is reliably performed with hypothermic circulatory arrest, but the best method of brain protection is controversial.

METHODS

We reviewed a consecutive series of 67 patients who had aortic arch repair with hypothermic circulatory arrest. Retrograde perfusion of arterial blood into the superior vena cava (SVC) during systemic arrest was used in 87%. Average age was 65 years. Acute dissection was present in 25%. Average circulatory arrest time was 37 minutes, and average temperature 17.7 degrees C.

RESULTS

Hospital mortality was 1.5%. Strokes occurred in 4.5%. Temporary neurological dysfunction occurred in 16%. Multivariate logistic regression analysis showed that acute dissection was the only independent predictor of the combined risk of stroke and temporary neurological dysfunction (odds ratio 8.5). Duration of circulatory arrest and patient age were not risk factors for adverse neurological outcome.

CONCLUSION

Continuous arterial perfusion of the SVC during hypothermic circulatory arrest provides excellent cerebral protection for aortic arch repair. Acute dissection is an independent risk factor for adverse neurological outcome. Arrest time is not a predictor of neurological dysfunction.

Cerebral effects of cold reperfusion after hypothermic circulatory arrest

OBJECTIVES

This study was undertaken to explore whether an interval of cold reperfusion can improve cerebral outcome after prolonged hypothermic circulatory arrest.

METHODS

Sixteen pigs (27-30 kg) underwent 90 minutes of circulatory arrest at a brain temperature of 20 degrees C. Eight animals were rewarmed immediately after hypothermic circulatory arrest (controls), and 8 were reperfused for 20 minutes at 20 degrees C and then rewarmed (cold reperfusion). Electrophysiologic recordings, fluorescent microsphere determinations of cerebral blood flow, calculations of cerebral oxygen consumption, and direct measurements of intracranial pressure (millimeters of mercury) were obtained at baseline (37 degrees C), before hypothermic circulatory arrest, after discontinuing circulatory arrest at 37 degrees C deep brain temperature, and at 2, 4, and 6 hours thereafter. Histopathologic features and percent brain water were determined after the animals were sacrificed.

RESULTS

Cerebral blood flow and oxygen consumption decreased during cooling: cerebral oxygen consumption returned to baseline levels after 4 hours, but cerebral blood flow remained depressed until 6 hours in both groups. Cold reperfusion failed to improve electrophysiologic recovery or to reduce brain weight, but median intracranial pressure increased significantly less after cold reperfusion than in controls (P =.02). Although no significant difference in the incidence of histopathologic abnormalities between groups was found, all 3 animals with an intracranial pressure of more than 15 mm Hg after immediate rewarming had histopathologic lesions, and high intracranial pressure was more prevalent among all animals with subsequent histopathologic lesions (P =.03).

CONCLUSIONS

Cold reperfusion significantly inhibited the rise in intracranial pressure seen in control pigs after 90 minutes of circulatory arrest at 20 degrees C, suggesting that cold reperfusion may decrease cerebral edema and thereby improve outcome after prolonged hypothermic circulatory arrest.

Total arch replacement using aortic arch branched grafts with the aid of antegrade selective cerebral perfusion

BACKGROUND

We report our clinical experience with total arch replacement using aortic arch branched graft in an attempt to determine the independent predictors of both in-hospital mortality and neurologic outcome.

METHODS

We studied 220 consecutive patients who underwent total arch replacement using aortic arch branched graft between May 1990 and June 1999. All operations were performed with the aid of hypothermic extracorporeal circulation, antegrade selective cerebral perfusion, and open distal anastomosis.

RESULTS

The overall in-hospital mortality rate was 12.7%. Multivariable analysis showed independent determinants of in-hospital mortality to be chronic renal failure, long pump time, participation in early series, and shock. Postoperative permanent neurologic dysfunction was 3.3%. On multivariable analysis, old cerebral infarct and pump time were independent determinants of permanent neurologic dysfunction. The selective cerebral perfusion time had no significant influence on in-hospital mortality or neurologic outcome. The 5-year survival rate including in-hospital deaths was 79% +/- 6%.

CONCLUSIONS

Selective cerebral perfusion allows increased ease of performance of total arch replacement, a complex and time-consuming procedure, and helps reduce periprocedural mortality and morbidity in patients with aortic arch aneurysm and those with acute aortic dissection.

Predictors of adverse outcome and transient neurological dysfunction after ascending aorta/hemiarch replacement

BACKGROUND

This study was undertaken to determine predictors of adverse outcome and transient neurological dysfunction after replacement of the ascending aorta with an open distal anastomosis.

METHODS

All 443 patients (300 male, median age 63) undergoing replacement of the ascending aorta with an open distal anastomosis between 1986 and 1998 were included in the analysis. The ascending aorta alone was replaced in 190 (42.9%); 253 (57.1%) also had proximal arch replacement. Median hypothermic circulatory arrest (HCA) time was 25 minutes (range 12 to 68). Either death or permanent neurological dysfunction were considered adverse outcome (AO).

RESULTS

Adverse outcome occurred in 11.5% (51 of 443) of patients overall: in 7.4% of elective (20 of 269) or urgent (4 of 54) operations, but in 17% (19 of 113) of emergencies. Multivariate analysis of the group as a whole revealed that significant (p < 0.05) independent preoperative predictors of AO were age greater than 60 [odds ratio (OR) 2.2], hemodynamic instability (OR 2.7), and dissection (OR 1.9). For the 435 operative survivors, procedural variables predictive of AO were contained rupture (OR 2.8) and HCA time (OR 1.03/min). When only the 271 elective patients were analyzed separately, the need for a concomitant procedure (p = 0.009, OR 3.6) and HCA time (p = 0.002, OR 1.06/min) were the only predictors of AO in multivariate analysis. Transient neurological dysfunction (TND) occurred in 86 of 392 patients (22%). Significant predictors of TND for all patients without AO were age (OR 1.06/y), HCA time (OR 1.04/min), coronary artery disease (OR 2.2), hemodynamic instability (OR 3.4), and acute operation (OR 2.2). Survival of discharged patients was 93% at 1 year and 83% at 5 years.

CONCLUSIONS

Early elective operation and shorter HCA time during ascending aorta/hemiarch surgery will reduce both AO and TND.

Surgical management of atherosclerotic aortic arch aneurysms using selective cerebral perfusion: 7-year experience in 52 patients

OBJECTIVE

Patients with atherosclerotic aortic arch aneurysms are at greater risk for brain complication. We report our techniques and results of operation using selective cerebral perfusion.

METHODS

We retrospectively analyzed 52 consecutive patients with atherosclerotic aortic arch aneurysms (mean age, 70 years, range, 53-86 years), who underwent operation between April 1992 and March 1999. The operation was non-elective in 11 patients (21.1%). Concomitant operations included eight coronary artery bypass grafting and one aortic valve replacement. Simultaneous distal aortic reconstruction was performed in three patients. The operation was performed through median sternotomy. To avoid brain embolism, total arch replacement with a branched prosthesis was performed in 48 patients, in an attempt to exclude affected segments of aorta. In addition, retrograde femoral artery perfusion was avoided and cerebral circulation was isolated before aortic manipulation. To achieve even blood flow distribution, we employed perfusion and continuous pressure monitoring of all the three arch vessels. The perfusion rate was 12+/-2 ml/kg per min and the pressure was kept around 50 mmHg. Deep hypothermic arrest of the lower torso (bladder temperature, 22 degrees C) was used during open distal aortic anastomosis.

RESULTS

The hospital mortality rate was 11.5% (six of 52), and 7.3% (three of 41) for elective cases. Only one patient (1. 9%) developed permanent focal neurological deficit. Six other patients showed temporary brain complications, which was global (delirium) in three and focal in three others.

CONCLUSIONS

Selective cerebral perfusion is a safe brain protection method, and our strategy seems effective for embolic stroke prevention.

Surgical techniques. Aortic arch and deep hypothermic circulatory arrest: real-life suspended animation

Surgical reconstruction of the aortic arch is a complex procedure requiring careful preoperative analysis of the pathology and forethought toward surgical approach. Development of surgical techniques has brought dramatic improvement survival and reduction of neurological events associated with these procedures, yet significant morbidity is still encountered. New approaches to the patient with these pathologies include antegrade and retrograde perfusions to the brain. Continued research into physiology of hypothermic circulatory arrest offers the promise of pharmacological protection of the brain during aortic reconstruction and potentially development of therapeutic modalities to treat and limit ischemic brain damage.