Antegrade cerebral perfusion with cold blood: a 13-year experience

Background. In 1986 we introduced the technique of antegrade selective perfusion of the brain with cold blood during surgery of the aortic arch.

Methods. Between January 1984 and March 1998, 171 patients (118 males and 53 females) aged 25 to 83 years (mean 56.5 ± 17), underwent replacement of the transverse aortic arch with the aid of cold blood antegrade selective perfusion. One hundred twenty two patients (71.3%) with chronic lesions were operated on electively; 49 patients (28.6%) were operated on urgently for acute aortic dissection (42 patients) or for a ruptured chronic aneurysm (7 patients). Fifty-one patients (29.8%) had previously undergone a surgical procedure on the thoracic aorta. Mean duration of cardiopulmonary bypass was 121 minutes (range: 65–248); mean duration of cerebral perfusion was 60 minutes (range: 15–90), and mean duration of systemic circulatory arrest circuit was 32 minutes (range: 10–57). The electroencephalogram, routinely recorded, showed disappearance of electrical activity in a mean of 9 minutes (range: 3–16) initial return of electrical activity after a mean of 12 minutes (range: 1–35) and normalization in a mean time of 66 minutes.

Results. All patients but 7 (4%) showed signs of normal awakening within 8 hours postoperatively. Six patients (3.5%) had fatal neurologic complications, and 16 patients (9.3%) had a non-fatal neurologic complications. Twenty-nine patients (16.9%) died during the post-operative hospital course. There was a significant difference between patients aged less than 60 years (9%) and patients older than 60 years (mortality rate 26.4%, p < 0.02). There was also a significant difference between patients undergoing an isolated replacement of the arch, and those in whom the replacement was extended to the descending aorta in whom mortality was 36.4% (χ², p < 0.02). Lesion and gender had no significant influence on the outcome of the patients, nor had the duration of cardiopulmonary bypass, circulatory arrest, and cerebral perfusion. In particular, no correlation could be established between the duration of cerebral perfusion and the occurrence of neurologic complications.

Conclusion. The clinical results obtained throughout this experience have demonstrated that selective antegrade cerebral perfusion with cold blood provides excellent protection during surgery of the transverse aortic arch. In addition, it avoids the use of deep hypothermia and prolonged cardiopulmonary bypass and does not limit the time allowed to perform the aortic repair. In our opinion it is the technique of choice, especially in frail patients or those requiring a long and difficult procedure.     

Extension of the “Elephant Trunk” Technique in Complex Aortic Pathology: The “Bidirectional” Option

Background. The “elephant trunk” technique, using a free-floating vascular prosthesis, was originally described to facilitate a subsequent operation on the downstream aorta. We developed an additional refinement of this technique, called the “bidirectional elephant trunk.” This option may represent an interesting tool in more complex aortic operations, especially when the descending aorta has to be replaced first in patients with concomitant pathology of the ascending aorta or of the aortic arch.

Methods. The initial operation is performed through a left thoracotomy. The proximal elephant trunk is created by invaginating the future aortic arch graft into the descending aortic graft. The proximal anastomosis between the doubled graft and the proximal descending aorta is performed first. During construction of the distal anastomosis, a distal elephant trunk may be inserted likewise. If the aortic arch and ascending aorta have to be replaced later, this second step is performed through a median sternotomy. The free-floating arch graft is pulled out of the proximal descending aorta with a nerve hook, unfolded, and used for total arch replacement.

Results. This technique was used successfully in 3 patients without mortality. No major complications were observed excepted persistent hoarseness in a patient with preoperative paresis of the recurrent nerve. No perfusion problems due to the unfolding of the free-floating graft occurred during the second operation.

Conclusions. The bidirectional elephant trunk technique is an interesting option that may be suitable for patients presenting with a complex pathology of the whole thoracic aorta when the descending segment has to be replaced first.     

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). Hemi-arch 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.     

Retrograde cerebral perfusion for aortic arch surgery: analysis of risk factors

Background. Retrograde cerebral perfusion (RCP) has been widely adopted during aortic arch surgery under hypothermic circulatory arrest (HCA). However, the risks in terms of mortality and morbidity in aortic arch surgery using HCA with RCP have not yet been confirmed.

Methods. The present study is a retrospective review of 249 patients who underwent aortic arch surgery at three Japanese cardiovascular centers where RCP is a routine adjunct. The median age was 65 years, and 38 patients were more than 75 years old. The pathology in the aortic arch was atherosclerotic aneurysm in 133 patients and dissection in 116. Seventy patients had surgery on an emergency basis. Surgery was performed through a median sternotomy in 182 patients and through a left thoracotomy in 67. Using HCA with RCP, graft replacement of the total aortic arch was performed in 109, the distal arch in 63, and the ascending aorta and hemi-arch in 66; 11 patients had patch repair.

Results. The overall hospital mortality was 25/249 (10%), and 12/70 (17%) in emergent surgery. Stroke developed in 11 patients (4%). The median duration of RCP was 46 minutes (range, 5 to 95). Univariate analysis of risk factors revealed that an age of 75 years or more (p < 0.001), and urgency of surgery (p = 0.02) affected hospital mortality. Multivariate logistic analysis revealed that pump time (p = 0.0001), age (p = 0.0001) and RCP time (p = 0.05) are the most significant risk factors for mortality. The risk factors for mortality and neurological morbidity combined are pump time (p = 0.0001), age (p = 0.0002), and urgency of surgery (p = 0.07); RCP time is marginally significant (p = 0.15).

Conclusions. The dominant risk factors for mortality and morbidity are pump time, urgency of the surgery, and age. RCP is a simple and useful adjunct for aortic arch surgery with up to 80 minutes of HCA, although prolonged RCP is a risk factor for mortality and morbidity.     

Aortic arch repair with right brachial artery perfusion

Background. To determine the effectiveness of unilateral selective cerebral perfusion for aortic arch repair and to discuss possible modifications to enhance technical simplicity.

Methods. In the period between January 1996 and April 2001, 104 patients underwent aortic arch repair with the use of right brachial artery low flow (8 to 10 mL/kg per minute) antegrade selective cerebral perfusion under moderate hypothermia (26°C). Mean patient age was 52 ± 12 years. Sixty-four patients presented with Stanford type A aortic dissection, including 12 with acute dissection; 38 patients had aneurysmal dilatation of the ascending aorta and aortic arch; and 2 patients had isolated arch aneurysm. Ascending and partial arch replacement was performed in 50 patients; ascending and total arch replacement in 33 patients; ascending and descending arch replacement in 19 patients; and isolated arch replacement in 2 patients.

Results. Mean antegrade cerebral perfusion time was 39 ± 22 minutes. One patient with acute proximal dissection died because of cerebral complications. One other patient developed right hemiparesis, which resolved during the second postoperative month without sequela. Other than these 2 cases (1.9%), no other neurologic event was observed.

Conclusions. The technique of low flow antegrade selective cerebral perfusion through the right brachial artery may be used for a vast majority of aortic aneurysms and dissections requiring arch repair. This technique does not necessitate deep hypothermia, requires shorter cardiopulmonary bypass and operation times, has the advantage of simplicity, provides optimal vascular repair without time restraints and, in terms of clinical results, is as safe as other techniques for cerebral protection.     

Hypothermic circulatory arrest does not increase the risk of ascending thoracic aortic aneurysm resection.

OBJECTIVE: The purpose of this study was to investigate the safety and efficacy of a period of deep hypothermic circulatory arrest (DHCA) during elective replacement of the ascending thoracic aorta. SUMMARY BACKGROUND DATA: DHCA has been implemented in ascending thoracic aortic aneurysm resection whenever the anatomy or pathology of the aorta or arch vessels prevents safe or adequate cross-clamping. Profound hypothermia and retrograde cerebral perfusion have been shown to be neurologically protective during ascending aortic replacement under circulatory arrest. METHODS: The authors conducted a retrospective analysis of 91 consecutive patients who underwent repair of chronic ascending thoracic aortic aneurysms from 1986 to present. The authors hypothesized that patients undergoing DHCA with or without retrograde cerebral perfusion during aneurysm repair were at no greater operative risk than patients who received aneurysm resection while on standard cardiopulmonary bypass. RESULTS: There were no significant differences in hospital mortality, stroke rate, or operative morbidity between patients repaired on DHCA when compared to those repaired on cardiopulmonary bypass. CONCLUSIONS: DHCA with or without retrograde cerebral perfusion does not result in increased morbidity or mortality during the resection of ascending thoracic aortic aneurysms. In fact, this technique may prevent damage to the arch vessels in select cases and avoid the possible complications associated with cross-clamping a friable or atherosclerotic aorta.     

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.     

Determinants of Early Mortality and Neurological Morbidity in Aortic Operations Performed Under Circulatory Arrest

OBJECTIVE: Aneurysms and dissections of the thoracic aorta continue to present a surgical challenge and their incidence is increasing in recent years. The mortality rate of surgical treatment is still higher than those of other cardiovascular operations. Neurological injury is the most feared complication resulting from repair of these lesions. This study aims to determine the factors that influence the neurological outcome and mortality after thoracic aortic operations. METHODS: During the period from November 1993 through May 1999, 144 patients were operated on for conditions involving the ascending aorta and/or aortic arch. Ninety-five (66.0%) were operated for aortic dissection and 49 (34.0%) were for aortic aneurysms. Sixty-two patients (43.1%) had replacement of ascending aorta with distal open technique; 82 patients (56.9%) had hemiarch or total arch replacement or repair of the distal arch. RESULTS: Twenty-seven (18.7%) early deaths occurred. New stroke occurred in two patients (1.4%) and temporary neurological dysfunction in nine patients (6.3%). Deep hypothermic circulatory arrest with retrograde cerebral perfusion was used in all patients. On multivariate logistic regression analysis, risk factors for mortality were chronic renal failure, preoperative organ malperfusion, rupture, total circulatory arrest time > 60 minutes, postoperative acute renal failure, postoperative low cardiac output, sepsis, and multiple organ failure. Risk factors for neurological morbidity were preoperative chronic renal failure, preoperative hemodynamic instability, postoperative low cardiac output, and pulmonary complications. CONCLUSIONS: Hypothermic circulatory arrest with retrograde cerebral perfusion was not an independent predictor of neurological morbidity on multivariate analysis, even if the arrest period was more than 60 minutes. Lengths of circulatory arrest periods and clinical presentations of the patients are important determinants of mortality.     

Surgery for thoracic aortic aneurysms involving the distal arch through a left thoracotomy

Surgical outcome for thoracic aortic aneurysms involving the distal arch via a left thoracotomy using retrograde cerebral perfusion combined with profound hypothermic circulatory arrest was reviewed. Twelve patients with a atherosclerotic aortic aneurysm between 1994 and 1997 were involved. A proximal aortic anastomosis was made by means of an open aortic technique. For the first four patients, oxygenated arterial blood from cardiopulmonary bypass was perfused retrogradely through a venous cannula positioned into the right atrium. In the last eight cases, venous blood provided by a low-flow perfusion of the lower half body via the femoral artery, which was still oxygen-saturated, was circulated passively in the brain in a retrograde fashion with the descending aorta clamped. Prosthetic replacement was done between the distal arch and the proximal descending aorta in 6 patients and from the distal arch to the entire descending thoracic aorta in 6 patients. The median duration of hypothermic circulatory arrest and continuous retrograde cerebral perfusion was 36 minutes and 33 minutes respectively. The overall outcome was satisfactory without early mortality--all patients survived, although an octogenarian died of respiratory failure 1 year postoperatively. Another octogenarian with a ruptured aneurysm developed delay of meaningful consciousness, and other two patients with a severely atherosclerotic aneurysm suffered permanent neurological dysfunction (stroke) presumably due to an embolic episode. The safe and simple combination of profound hypothermic circulatory arrest, retrograde cerebral perfusion, and open aortic anastomosis protects the brain adequately and produces satisfactory results in surgery for aortic aneurysms involving the distal arch through a left thoracotomy.     

Central arterial cannulation and the arch first method for aortic arch aneurysm repair.

BACKGROUND: We investigated whether the axillary artery or ascending aorta cannulation combined with the arch first method decreases the risk of stroke during total arch replacement. PATIENTS AND METHODS: From January 2002 to January 2006, 35 total arch replacements were performed with the arch first method and central arterial cannulation. The mean age was 66+/-10 years. The cannulation sites were the axillary artery in 19 and the ascending aorta in 16. The arch first method (a short period of deep hypothermic circulatory arrest with retrograde cerebral perfusion and then subsequent antegrade cerebral perfusion) was used in all patients. RESULTS: The mean retrograde cerebral perfusion time was 29+/-7 min. The incidence of the permanent neurological dysfunction related to the surgical procedures was 2.9% (1/35). Hospital mortality was 5.7% of patients (2/35). There was no difference in the operative outcome between the 2 arterial inflow sites. CONCLUSION: At the time of total arch replacement, the use of central arterial cannulation and the arch first method are effective methods for preventing permanent brain injury. Cannulation of the ascending aortic using Dispersion cannula perfusing toward the aortic valve is considered to be a safe and favorable method for central arterial cannulation.     

Screening Carotid Ultrasonography and Risk Factors for Stroke in Coronary Artery Surgery Patients

Background. The role of noninvasive carotid artery screening in relation to other clinical variables in identifying patients at increased risk of stroke after coronary artery bypass grafting was examined.

Methods. Preoperative, intraoperative, and postoperative clinical data were prospectively collected for 1,835 consecutive patients undergoing first-time isolated coronary artery bypass grafting between March 1990 and July 1995, 1,279 of whom had screening carotid ultrasonography. All patients with postoperative neurologic events were identified and reviewed in detail. Average patient age was 65.3 years (range, 33 to 92 years), and 9.3% (171 patients) had a prior permanent stroke or transient ischemic attack. Hospital and 30-day mortality was 2.2% (41 patients). Forty-five patients (2.5%) had a transient or permanent postoperative neurologic event. The data were analyzed by stepwise logistic regression to determine the independent predictors of both significant carotid stenosis and stroke.

Results. On multivariate analysis, the clinical predictors of significant carotid stenosis were age (p < 0.0001), diabetes (p = 0.0123), female sex (p = 0.0026), left main coronary stenosis greater than 60% (p < 0.0001), prior stroke or transient ischemic attack (p = 0.0008), peripheral vascular disease (p = 0.0001), prior vascular operation (p = 0.0068), and smoking (p < 0.0001). When all variables were evaluated for those patients who underwent noninvasive carotid artery screening, the independent predictors of postoperative neurologic event were prior stroke or transient ischemic attack (p < 0.0001), peripheral vascular disease (p = 0.0037), postinfarction angina pectoris (p = 0.0319), postoperative atrial fibrillation (p = 0.0014), carotid stenosis greater than 50% (p = 0.0029), cardiopulmonary bypass time (p = 0.0006), significant aortic atherosclerosis (p = 0.0054), postoperative amrinone or epinephrine use (p = 0.0054), and left ventricular ejection fraction less than 0.30 (p = 0.0744).

Conclusions. The etiology of postoperative stroke is multifactorial. Selective use of carotid ultrasonography is of value in identifying patients who are at greater risk of postoperative stroke independent of other variables and should be considered before coronary artery bypass grafting, particularly in patients with a history of neurologic event or peripheral vascular disease.     

Extracorporeal circulation for great vessels surgery: a review of 131 cases

A retrospective analysis of 131 cases of major vascular surgery, mainly aneurysms of the ascending and descending aorta, was undertaken to determine whether use of different bypass methods chosen according to location of the individual lesions resulted in improved results. For the 93 cases of ascending aortic aneurysm, the method for cardiac protection was improved by the use of continuous retrograde coronary sinus perfusion with cardioplegic blood. In sixteen cases with dissection involving the aortic arch, deep hypothermic circulatory arrest and continuous retrograde cerebral perfusion through the superior vena cava was employed for brain protection. The safe brain circulation arrest time was thus prolonged to the longest record of 81 minutes. Among the group of 93 cases, there were four operative and four hospital deaths, giving a mortality rate of 8.6% (8/93). For the 34 cases of descending aortic aneurysms, left heart bypass was employed to avoid ischemia of the heart, lungs, brain, and the abdominal organs; the operative mortality rate was 8.8% (3/34). In three cases of interrupted aortic arch, separate upper and lower body perfusion under deep hypothermia with low flow rate perfusion for the upper body provided the necessary conditions for radical surgery. In one patient with Budd-Chiari syndrome, a total corrective surgery was achieved under right heart bypass.     

Staged repair of extensive aortic aneurysms: long-term experience with the elephant trunk technique

OBJECTIVE: This paper reports our experience of a large series of elephant trunk patients accumulated over 12 years. SUMMARY BACKGROUND DATA: Extensive aneurysms of the ascending/arch and descending thoracic or thoracoabdominal aorta are significant surgical problems that have potential for great morbidity. We adopted a staged approach known as the elephant trunk procedure in 1991, and we have used it with some modifications since that time. METHODS: Between February 1991 and December 2003, we performed 1660 operations for ascending/arch or descending thoracic/thoracoabdominal aortic aneurysms. Of these, 321 operations were performed in 218 patients for extensive aneurysms with the elephant trunk technique. We performed 218 ascending/arch repairs and 103 descending thoracic or thoracoabdominal aortic replacements. RESULTS: In 218 ascending/arch repairs, strokes occurred in 3 of 218 (2.7%) patients, with 1 of 187 (0.5%) in the retrograde cerebral perfusion group and 2 of 31 (6.5%) in the no-retrograde cerebral perfusion group (odds ratio 0.08, P < 0.009). Thirty-day mortality for this group was 19 of 218 (8.7%). Among 199 recovering patients after stage 1 repair, 4 of 199 (2%) died during the 30-day to 6-week interval between stages. After stage 2 repair, 0 of 103 patients experienced immediate neurologic deficit, and 10 of 103 (9.7%) died within 30 days of surgery. Actuarial survival after completed stage 2 was 71% at 5 years. CONCLUSION: Despite extreme underlying disease, long-term survival is excellent in patients with extensive aneurysms when both stages of repair are completed. To prevent rupture, the second stage should be completed as soon as the patient's condition permits, preferably within 6 weeks.     

Predictive factors for mortality and cerebral complications in arteriosclerotic aneurysm of the aortic arch

BACKGROUND: The incidence of cerebral complications is high in patients with aortic arch aneurysm. METHODS: Between December 1977 and December 1995, 246 patients with arteriosclerotic arch aneurysm underwent operation. Thirty-nine patients had an aneurysm involving the entire arch, 193 had only distal arch aneurysm, and 14 had arch aneurysm extending to the descending aorta. Eighty-seven patients underwent replacement of the total arch, 85 had replacement of only the distal arch, 14 had simultaneous replacement of the descending aorta, 45 had patch repair, and 15 had thromboexclusion. Selective cerebral perfusion was used in 112 patients and partial bypass in 58 in the earlier series of patients, but deep hypothermic circulatory arrest with retrograde cerebral perfusion technique was exclusively applied in the most recent 76 patients. RESULTS: There were 50 (20%) early deaths and 37 (19%) late deaths. Postoperative stroke was found in 26 (11%) patients of which 13 (50%) died. Mutual predictive factors for postoperative mortality and stroke were earlier series, preoperative chronic renal failure, ruptured aneurysm, arch clamping during procedure, and using partial cardiopulmonary bypass. Among 129 patients operated on during the most recent 5 years, early mortality and incidence of stroke decreased to 14.7% and 6.9%, respectively. CONCLUSIONS: Results of operations for arteriosclerotic aneurysms of the transverse aortic arch in 246 patients during a period of 17 years have been improving but are still not satisfactory.     

Determination of cerebral blood flow dynamics during retrograde cerebral perfusion using power M-mode transcranial Doppler

BACKGROUND: Retrograde cerebral perfusion (RCP) during profound hypothermic circulatory arrest has been used as an adjunct for cerebral protection for repairs of the ascending and transverse aortic arch. Transcranial Doppler ultrasound has been used to monitor cerebral blood flow during RCP with varying success. The purpose of this study was to characterize cerebral blood flow dynamics during RCP using a new mode of monitoring known as transcranial power motion-mode (M-mode) Doppler ultrasound. METHODS: Data on pump-flow characteristics and patient outcomes were collected prospectively for patients undergoing ascending and transverse aortic arch repair. Retrograde cerebral perfusion during profound hypothermic circulatory arrest was used for all operations. Intraoperative cerebral blood flow dynamics were monitored and recorded using transcranial power M-mode Doppler ultrasound. RESULTS: Between August 2001 and March 2002, we used transcranial power M-mode Doppler ultrasound monitoring for 40 ascending and transverse aortic arch repairs during RCP. Mean RCP time was 32.2 +/- 13.8 minutes. Mean RCP pump flow and RCP peak pressure for identification of cerebral blood flow were 0.66 +/- 0.11 L/min and 31.8 +/- 9.7 mm Hg, respectively. Retrograde cerebral blood flow during RCP was detected in 97.5% of cases (39 of 40 patients) with a mean transcranial power M-mode Doppler ultrasound flow velocity of 15.5 +/- 12.3 cm/s. In the study group, 30-day mortality was 10.0% (4 of 40 patients). The incidence of stroke was 7.6% (3 of 40 patients); the incidence of temporary neurologic deficit was 35.0% (14 of 40 patients). CONCLUSIONS: Transcranial power M-mode Doppler ultrasound consistently demonstrated retrograde middle cerebral artery blood flow during RCP. Transcranial power M-mode Doppler ultrasound can provide optimal RCP with individualized settings of pump flow.     

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.     

Arch and descending aortic aneurysms: influence of perfusion technique on neurological outcome.

OBJECTIVE: Although cannulation of the femoral artery is used routinely for thoracic aortic operations with hypothermic circulatory arrest, retrograde perfusion through the descending aorta carries the risk of cerebral malperfusion or embolism. We have, therefore, routinely used a central cannulation technique for distal arch and descending aortic operations since 1995. In this study, we compared neurological outcome in consecutive patients undergoing femoral versus ascending aortic perfusion for these aneurysms. METHODS: Between 1987 and 1998, 61 patients underwent aortic resection with circulatory arrest, but without retrograde cerebral perfusion, for lesions of the aortic arch and descending aorta. Thirty-one patients had fusiform true aneurysms, 19 had aortic dissection and 11 had extensive saccular or false aneurysms. Thirty-two patients (52%) were perfused via the femoral artery (group A), and 29 patients (48%) from the ascending aorta (group B). Operative mortality and morbidity, and neurological outcome, were reviewed. RESULTS: There were no differences between the groups in mean age, pathology, abdominal and peripheral vascular disease, net perfusion time, or circulatory arrest time. There were four hospital deaths (three in group A and one in group B; P = 0.61), including one neurological death in group A, group A suffered a higher incidence of neurological events (nine patients: 28%) than group B (two patients: 7%; P = 0.03). Temporary focal neurological deficits occurred in both groups (two patients in group A, 6% and two patients in group B, 7%; P > 0.99), but permanent injury occurred exclusively in group A (seven patients: four with monoplegia, one with hemiplegia, and two with diffuse cerebral injury with one death; P = 0.01). CONCLUSIONS: Anterograde perfusion using a proximal aortic cannula provides a low risk of cerebral embolism and allows extensive aortic resection with low morbidity.     

S100β correlates with neurologic complications after aortic operation using circulatory arrest

Background. Astrocyte protein S100β is a potential serum marker for neurologic injury. The goals of this study were to determine whether elevated serum S100β correlates with neurologic complications in patients requiring hypothermic circulatory arrest (HCA) during thoracic aortic repair, and to determine the impact of retrograde cerebral perfusion (RCP) on S100β release in this setting.

Methods. Thirty-nine consecutive patients underwent thoracic aortic repairs during HCA; RCP was used in 25 patients. Serum S100β was measured preoperatively, after cardiopulmonary bypass, and 24 hours postoperatively.

Results. Neurologic complications occurred in 3 patients (8%). These patients had higher postbypass S100β levels (7.17 ± 1.01 μg/L) than those without neurologic complications (3.63 ± 2.31 μg/L, p = 0.013). Patients with S100β levels of 6.0 μg/L or more had a higher incidence of neurologic complications (3 of 7, 43%) compared with those who had levels less than 6.0 μg/L (0 of 30, p = 0.005). Retrograde cerebral perfusion did not affect S100β release.

Conclusions. Serum S100β levels of 6.0 μg/L or higher after HCA correlates with postoperative neurologic complications. Using serum S100β as a marker for brain injury, RCP does not provide improved cerebral protection over HCA alone.     

Closed-Chest Cardiopulmonary Bypass and Cardioplegia: Basis for Less Invasive Cardiac Surgery

Background. We developed a method of closed-chest cardiopulmonary bypass to arrest and protect the heart with cardioplegic solution. This method was used in 54 dogs and the results were retrospectively analyzed.

Methods. Bypass cannulas were placed in the right femoral vessels. A balloon occlusion catheter was passed via the left femoral artery and positioned in the ascending aorta. A pulmonary artery vent was placed via the jugular vein. In 17 of the dogs retrograde cardioplegia was provided with a percutaneous coronary sinus catheter.

Results. Cardiopulmonary bypass time was 111 ± 27 minutes (mean ± standard deviation) and cardiac arrest time was 66 ± 21 minutes. Preoperative cardiac outputs were 2.9 ± 0.70 L/min and postoperative outputs were 2.9 ± 0.65 L/min (p = not significant). Twenty-one-French and 23F femoral arterial cannulas that allowed coaxial placement of the ascending aortic balloon catheter were tested in 3 male calves. Line pressures were higher, but not clinically limiting, with the balloon catheter placed coaxially.

Conclusions. Adequate cardiopulmonary bypass and cardioplegia can be achieved in the dog without opening the chest, facilitating less invasive cardiac operations. A human clinical trial is in progress.     

升主动脉和弓部动脉瘤的外科治疗

目的：总结升主动脉和弓部动脉瘤手术治疗经验，以期进一步提高手术疗效。方法：自2000年7月至2002年5月应用深低温停循环（DHCA）和上腔静脉逆行脑灌注（RCP）技术手术治疗升主动脉和弓部动脉瘤20例，其中急症手术5例。施行全弓置换术2例，全弓置换和象鼻手术3例，半弓置换术15例。同期行Bentall手术8例，升主动脉置换术或同时行主动脉瓣置换术12例，冠状动脉旁路移植术1例。结果：术后早期死亡1例，短时间浅昏迷1例，呼吸功能不全2例，肾功能不全2例，无晚期死亡。结论：DHCA和RCP技术是手术治疗升主动脉和弓部瘤的安全、有效方法，急性A型夹层动脉瘤的手术方式取决于内膜破裂口的位置；正确掌握DHCA和RCP技术，手术方式和手术技术、围术期处理是提高手术疗效的关键因素。