Aortic aneurysm: current status of surgical treatment

Management of Thoracic Aneurysm

A review of the literature on the management of thoracic aneurysm is presented. These patients have various comorbid conditions and need thorough work-ups. Aneurysms can be classified according to shapes and locations. Various methods to maintain hemodynamic stability with adequate endorgan perfusion are presented. The success of the operation depends upon preoperative anticipation and preparation for adequate organ perfusion and hemodynamic stability along with good communication between the anesthesiologist and the surgical team.

Improved Intraoperative Management of Anastomotic Bleeding during Aortic Reconstruction: Results of a Randomized Controlled Trial

In a randomized controlled trial, the effectiveness of a polymeric surgical sealant (CoSeal) was compared to Gelfoam/thrombin for managing anastomotic bleeding after implantation of Dacron grafts during aortic reconstruction for nonruptured aneurysms. Each treatment was directly applied to the suture line after confirmation of anastomotic bleeding. The proportion of suture line sites that achieved immediate sealing and the proportion sealed within 5 minutes were determined among 37 experimental (59 sites) and 17 control subjects (27 sites). A significantly greater proportion of bleeding suture line sites treated with the polymeric sealant achieved immediate sealing following reestablishment of blood flow compared with control-treated sites [48 of 59 (81%) vs 10 of 27 (37%); P = 0.002]. The difference between treatment groups was maintained after 5 minutes with approximately 85 per cent (50 of 59) of CoSeal sites compared to just over one-half (14 of 27) of control sites demonstrating ultimate sealing ( P = 0.01). There were no adverse events related to the use of the polymeric sealant in this study. These results support the use of this novel sealant for the intraoperative management of anastomotic bleeding during aortic reconstruction procedures.

Advances in the surgical repair of ruptured abdominal aortic aneurysms

Over the past two decades, the mortality rate for elective repair of infrarenal abdominal aortic aneurysms has improved to an acceptable level (< 5%). However, surgical results of ruptured abdominal aortic aneurysms have remained fairly constant with about 50% in hospital mortality rates. Growing experience with the use of the left retroperitoneal exposure for elective aortic surgery allowed the authors to extend the use of this technique to the repair of ruptured abdominal aortic aneurysm. The extended left retroperitoneal approach using a posterolateral exposure through the 10th intercostal space allowed the surgeon expeditiously and reliably to obtain supraceliac aortic control by dividing the left crus of the diaphragm in all patients. In total, 104 aortic replacements were performed for ruptured abdominal aortic aneurysm during the past 7 years. Of these patients, 87 were men and 17 women; mean(range) age was 72(52-95) years. Hemodynamic instability (as defined by a systolic blood pressure of < 90 mmHg) was present before surgery in 41% (43/104) of patients. The operative mortality rate was 27.9% (29/104). Preoperative hemodynamic instability, time of operative delay and aortic cross-clamp time did not correlate with operative mortality. The median duration of intensive care unit stay was 4 (range 1-60) days and hospital stay 11 (range 6-175) days. The results of this series identified that a change in the operative technique for the repair of ruptured abdominal aortic aneurysm beneficially affected patient survival. The authors suggest that expeditious supraceliac control without thoracotomy is an excellent alternative and offers an advantage in the surgical management of ruptured abdominal aortic aneurysm.

Intraoperative identification of spinal cord blood supply during repairs of descending aorta and thoracoabdominal aorta

OBJECTIVE

The aim was to intraoperatively identify the spinal cord blood supply and shorten the aortic crossclamp time.

METHODS

A platinum electrode was placed intrathecally by lumbar puncture alongside the spinal cord. After the aorta was crossclamped, hydrogen in a saline solution was injected into the aorta and, if it was shown that the segment supplied the spinal cord and there were multiple arteries, then these were individually injected. The repair was performed by a sequential segmental method as described previously.

RESULTS

Postoperatively, highly selective angiography was used to confirm that reattached intercostal arteries supplied the spinal cord. The technique was accurate in all patients. Five spinal cord perfusion patterns were noted: (1) direct, (2) collateral, (3) no direct supply from segment tested, (4) from atriofemoral bypass, and (5) occluded reattached intercostals. When no response was obtained or no further testing was required (n = 8), testing time was 4.2 minutes and crossclamp time 41.9 minutes. When multiple segmental arteries required further testing, the mean testing time was 10.4 minutes and crossclamp time 58.5 minutes, including reattachment of intercostal vessels (p = not significant).

CONCLUSION

Preliminary findings indicate that this method is a safe research technique, can detect radicular arteries, and may reduce the time for aortic crossclamping if no vessels are identified as supplying the spinal cord.

Routine coronary arteriography before abdominal aortic aneurysm repair

BACKGROUND

As cardiac complications constitute the principal cause of early and late morbidity and mortality after the surgical treatment of abdominal aortic aneurysm (AAA), a prospective study was planned to evaluate the effects of revascularization of coronary arteries on survival after AAA repair during early and long-term follow-up periods.

PATIENTS AND METHODS

A total of 125 patients underwent elective repair of AAA between 1986 and 1994. Coronary arteriography was performed in all cases. All cases with critical left anterior descending artery (LAD) lesions underwent a coronary artery bypass operation either simultaneously or shortly before AAA repair. In addition, percutaneous transluminal coronary angioplasty (PTCA) was performed for symptomatic and critical stenosis of arteries other than the LADs, or if noncritical but symptomatic stenosis of the LADs existed. Early and late follow-up data were obtained for all cases, and late-term cumulative survival rates were calculated.

RESULTS

Coronary artery lesions were found in 66 (53%) cases. In 24 cases, AAA repairs were performed 2.3 (mean) months after coronary artery bypass grafting (CABG), whereas in 4 cases both procedures were performed simultaneously. PTCA was performed in 4 cases 3 to 4 days prior to the abdominal surgery. Even though the coronary artery lesions were found inoperable in 7 cases, these patients underwent repair of AAA because of rapidly expanding and painful aneurysms. Early mortality rate was 4% (5 cases), in which 3 of these were from the group inoperable for CABG. A mean follow-up of 3.17 years (3 to 87 months) was achieved for all discharged patients. Cumulative survival rates for 6 months and 1, 2, 3, and 6 years were 99%, 99%, 95%, 93%, and 89%, respectively.

CONCLUSIONS

The results of this study emphasize the importance of coronary artery revascularization for early, and especially for late, survival after AAA repair.

Pathogenesis of spinal cord injury during simulated aneurysm repair in a chronic animal model

The pathogenesis of paraplegia after repair of thoracic aortic aneurysms is controversial. Using direct spinal cord evoked potential monitoring, critical intercostal arteries (CICA) were identified to evaluate the impact of backbleeding and ligation versus that of preservation during simulated aneurysm repair. Thirty pigs (40 kg) were randomly assigned to one of five groups. In groups 1 through 4, a thoracic segment containing CICA was cross-clamped for 60 minutes and distal aortic perfusion was provided by a centrifugal pump. In groups 1 and 2, the thoracic segment was vented, maintaining segment pressure at 0 mm Hg; CICA were ligated in group 1 and preserved in group 2. Thoracic segment was perfused at 70 mm Hg in groups 3 and 4; CICA were ligated in group 3 and preserved in group 4. Critical intercostal artery ligations were performed at the end of the cross-clamp period. In group 5 simple cross-clamping at the left subclavian artery was performed as a control. The combination of venting and ligation of CICA correlated with impaired neurologic outcome according to Tarlov's score (median, 1.5 in group 1 versus 3 in group 2; p = 0.015), indicated by a significant difference in median values of direct spinal cord evoked potential amplitude (expressed as a fraction of baseline values) at 120 minutes after cross-clamping (0.76 in group 1 versus 0.98 in group 2; p = 0.0082).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of segmental arteries, extent, and atriofemoral bypass on postoperative paraplegia after thoracoabdominal aortic operations

PURPOSE

The purpose of this article was to study the influence of either reattachment or oversewing of patient segmental intercostal or lumbar arteries, extent of aneurysm, and atriofemoral bypass on the incidence of postoperative paraplegia/paraparesis in patients at high risk with type I or II thoracoabdominal aneurysms.

METHODS

Data were prospectively collected on 99 patients undergoing type I or II thoracoabdominal aneurysm repairs, including exact extent of repair and whether atriofemoral bypass ws used. Patency of intercostal arteries from T3 to T12 and lumbar arteries from L1 to L4 were checked by intraoperative inspection. If the arteries were patent, note was taken of whether they were reattached to the new aortic prosthesis. Postoperative neurologic motor function was graded daily for the first 5 days, and the worst score in the first 30 postoperative days (POD) was used for analysis.

RESULTS

Ninety-five of 99 (96%) patients were 30-day survivors. By POD 30, 31 of 98 (32%) patients had had a neurologic deficit. There was no difference in the incidence of deficits according to whether lumbar or intercostal arteries were reattached, ignoring the effect of patency of the arteries. Of greater importance, however, was whether patent segmental arteries were oversewn at specific levels. Thus, for patients who had one or more arteries at T11, T12, or L1 oversewn (often because they could not be reattached), a deficit developed in 11 of 23 (48%) patients versus 20 of 75 (27%) patients who did not have patent arteries or had all patient arteries reattached (p = 0.05, odds ratio = 2.5). More specifically, if all arteries at this level were oversewn, a neurologic deficit developed in 63% of patients versus 23% if all their arteries were reattached (p = 0.01). Reattachment of patent arteries at individual levels from T7 to L4 showed a trend toward a lower risk of deficits but did not reach statistical significance. On multivariate analysis, atriofemoral bypass was associated with a lower risk of paralysis (p = 0.068), and significantly so when controlled for age (p = 0.0329, odds ratio 0.287). Subgrouping of extent type I thoracoabdominal aneurysms resulted in an incidence of paralysis of 14% (3/22) for subgroup A and 23% (5 of 22) for subgroup B compared with 43% (23 of 55) for type II thoracoabdominal aneurysms (type I [8 of 44 18%], versus type II [p = 0.0097]).

CONCLUSION

Patients with no or few patent segmental arteries in the aortic segment being replaced have a lower risk of neurologic deficits, compared with those with patent arteries. Every effort should be made to reattach all arteries at T11, T12, and L1 and, when possible within the constraints of technical feasibility and time, also those from T7 to L4. Preoperative angiography or intraoperative hydrogen testing may better identify the arteries that need to be reattached. When feasible, atriofemoral bypass appears to be protective, particularly when sequential clamping and segmental repairs can be performed.

A review of 103 cases with elective repair for abdominal aortic aneurysm: an analysis of the risk factors based on postoperative complications and long-term follow-up

From 1982 through 1992, 103 patients (mean age: 69 years) underwent an elective repair of an abdominal aortic aneurysm (AAA) at our institution. One or more postoperative complications occurred in 30 patients (29%), with a mortality rate of 1.9%. Factors which were found to be significantly associated with postoperative complications based on an univariate analysis included male sex (P = 0.0082), operation time (P = 0.0006), the size of the aneurysm (P = 0.0045), the amount of blood loss during operation (P = 0.0037), poor lung function (P = 0.0155), and the platelet count (P = 0.0468). A simple linear regression analysis showed that there were significant correlations among the AAA size, the duration of operation and the amount of blood loss. The age at operation, however, did not influence morbidity or mortality. Complete survival information was obtained in 96 (95%) patients, while the influence of preoperative risk factors on late survival was also examined by the Kaplan-Meier method. The factors influencing long-term survival were determined to be renal dysfunction and age at the time of operation.

Intrathecal perfusion of an oxygenated perfluorocarbon prevents paraplegia after aortic occlusion

A canine model was used to evaluate the effects of continuous intrathecal perfusion of an oxygenated perfluorocarbon emulsion on systemic and cerebral hemodynamics and neurologic outcome after 70 minutes of normothermic aortic occlusion. Twelve mongrel dogs were instrumented to monitor proximal and distal arterial blood pressure, cerebrospinal fluid pressure, spinal cord perfusion pressure, and somatosensory evoked potentials. The intrathecal perfusion apparatus consisted of two perfusing catheters, placed in the intrathecal space through a laminectomy, and a draining catheter percutaneously inserted in the cisterna cerebellomedullaris. The aorta was cross-clamped just distal to the left subclavian artery for 70 minutes. Animals were randomized into two groups: group 1 (n = 6) animals were treated with intrathecal perfusion of saline solution, whereas group 2 (n = 6) animals received oxygenated Fluosol-DA 20%. Data were acquired at baseline, during the cross-clamp period, and after reperfusion. Normothermic Fluosol or saline solution was infused at a rate of 15 mL/min beginning 15 minutes before cross-clamping and continued throughout the ischemic interval. There was no difference in proximal arterial blood pressure (97.2 versus 95.4 mm Hg; p > 0.05) or distal arterial blood pressure (14.6 versus 15.0; p > 0.05) between the two groups throughout the cross-clamp interval. Cerebrospinal fluid pressure rose significantly in both groups with the onset of intrathecal perfusion of either saline solution or Fluosol (7 +/- 1 versus 24 +/- 5 and 8 +/- 1 versus 40 +/- 4 mm Hg, respectively; p < 0.05). The rise in cerebrospinal fluid pressure was sustained throughout the perfusion interval in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The management of small abdominal aortic aneurysms: a computer simulation using Monte Carlo methods

Many small abdominal aortic aneurysms can now be identified by ultrasound screening and it is necessary to decide whether the risks of enlargement and rupture justify elective surgery. A computer simulation of the behaviour of small aneurysms has been constructed using Monte Carlo methods to model patterns of enlargement and rupture. The effect of policy with regard to the observation and timing of intervention has been evaluated for different patient groups. The results demonstrate the value of early intervention in otherwise fit patients with expected operative mortality rates of 5% or below, whereas, for older patients (over 70 years old) 6-monthly screening and operation if the aneurysm exceeds 5 cm is suggested. Higher risk patients with expected operative mortality of over 10% may be better treated conservatively up to an aneurysm diameter of 7 or 8 cm. The method used for simulation is flexible, being easily adjusted to take account of new information, and may have applications in other areas of clinical decision making.

Influence of preservation or perfusion of intraoperatively identified spinal cord blood supply on spinal motor evoked potentials and paraplegia after aortic surgery

Permanent ligation of arteries supplying blood to the spinal cord in operations for aortic aneurysm can lead to spinal cord ischemia, which can result in either paraparesis or paraplegia. This report describes a rapid method of intraoperative identification of those arteries that supply the spinal cord by use of an intrathecal platinum electrode to detect hydrogen in solution that has been injected into the aortic ostia. Preservation or perfusion of those identified arteries supplying the spinal cord may decrease the rate of postoperative neurologic complications. Of 28 porcine experiments with postoperative observation for 24 hours, there were 3 initial pilot experiments in which saline saturated with hydrogen was injected into the temporarily cross-clamped aorta. Twenty animals were then randomized to (1) preservation of only the vessels sequentially identified to supply blood to the spinal cord from T-13 to L-5 (n = 10); (2) division of the vessels supplying the spinal cord (n = 10). A further five animals underwent perfusion experiments wherein the identified cord arteries were perfused by a shunt, the other nonsupply arteries were divided, and the aorta was kept clamped for 45 minutes. Spinal motor evoked potentials were elicited with an intrathecal electrode and were highly sensitive for paralysis. Paralysis occurred in 0/3 pilot (p less than 0.013 vs division); 8/10 division; 1/10 preservation (p less than 0.0017 vs division); and perfusion 1/5 (p less than 0.025 vs division). Results of a pilot study in eight humans shows that the technique can be used to rapidly identify segmental arteries supplying the spinal cord, to determine if distal perfusion is supplying the spinal cord with blood flow, and if reattached segmental arteries are patent.

Selective evaluation and management of coronary artery disease in patients undergoing repair of abdominal aortic aneurysms. A 16-year experience

Reduction of cardiac mortality associated with abdominal aortic aneurysm (AAA) repair remains an important goal. Five hundred consecutive urgent or elective operations for infrarenal nonruptured AAA were reviewed. Patients were divided into three groups based on preoperative cardiac status: group I (n = 260, 52%), no clinical or electrocardiographic (ECG) evidence of coronary artery disease (CAD); group II (n = 212, 42.2%), clinical or ECG evidence of CAD considered stable after further evaluation with studies such as dipyridamole-thallium scanning, echocardiography, or coronary arteriography; group III (n = 28, 5.6%), clinical or ECG evidence of CAD considered unstable after further evaluation. Group I had no further cardiac evaluation and groups I and II underwent AAA repair without invasive treatment of CAD. Group III underwent repair of cardiac disease before (n = 21) or coincident with (n = 7) AAA repair. In all instances, perioperative fluid volume management was based on left ventricular performance curves constructed before operation. The 30-day operative mortality rate for AAA repair in all 500 patients was 1.6% (n = 8). There was one (0.4%) cardiac-related operative death in group I, which was significantly less than the five (2.4%) in group II (p less than 0.02). Total mortality for the two groups were also significantly different, with one group I death (0.4%) and seven group II deaths (3.3%), (p less than 0.02). These data support the conclusions that (1) the leading cause of perioperative mortality in AAA repair is myocardial infarction, (2) correction of severe or unstable CAD before or coincident with AAA repair is effective in preventing operative mortality, (3) patients with known CAD should be investigated more thoroughly to identify those likely to develop perioperative myocardial ischemia so that their CAD can be corrected before AAA repair, and (4) patients with no clinical or ECG evidence of CAD rarely die of perioperative myocardial infarction, and thus selective evaluation of CAD based on clinical grounds in AAA patients is justified.

Supraceliac clamping: an underused alternative in aortic surgery

In the majority of patients undergoing abdominal aortic surgery, proximal clamping can be readily achieved below the renal vessels. In some situations however, this may be difficult, impossible or ill advised, and an alternative method of control must be sought. We describe the technique and report our personal experience with supraceliac clamping, a maneuver which merits more widespread use in emergency and difficult infrarenal aortic surgery.

Preliminary report of localization of spinal cord blood supply by hydrogen during aortic operations

One source of paraplegia after aortic operations is the failure to reattach the spinal cord blood supply, the origins of which are not evident at operation. This report is concerned with a rapid new method of identifying these vessels intraoperatively. In 9 pigs, a specially designed catheter with platinum and stainless steel electrodes was inserted intrathecally. Saline solution saturated with hydrogen was injected sequentially into arterial ostia at T-15 to L-4 inclusive, and the generated current impulses from the conditioned platinum electrode were recorded. Of 90 potential segmental arteries supplying the spinal cord, 28 gave rise to spinal radicular arteries. Hydrogen-induced current impulses correctly located 25 of the radicular arteries and all those larger than 180 microns in diameter. When injected with indigo carmine, the vessels localized by the hydrogen-induced current impulses filled the entire anterior spinal artery from the low thoracic to the sacral region, whereas injection of the other vessels did not show filling. After refinement and testing for safety, this method has been employed clinically to rapidly localize and reattach routes of critical cord circulation.

Management of ruptured or symptomatic abdominal aortic aneurysms

During the past 15 years, the operative mortality for elective repair of abdominal aortic aneurysms has declined; this favorable trend has very likely resulted from simplified operative technique and improved perioperative management. Unfortunately, however, there has been no comparable decline in the mortality associated with repair of ruptured abdominal aortic aneurysms. The management of these patients remains a challenge to even the most skilled and experienced vascular surgeon.

Clamp/repair: a safe technique for treatment of blunt injury to the descending thoracic aorta

Debate exists with regard to the use of pump bypass, shunt bypass, or clamp/repair techniques in treating injuries to the descending thoracic aorta. The objective in using any of these techniques is to minimize the complications of paraplegia and renal failure, while achieving the lowest possible mortality. During an eighteen-year period, 45 patients were seen with acute blunt injury to the descending thoracic aorta. The shunt bypass method of repair was used in 1; pump bypass in 8; and clamp/repair in 23. There were desperate unsuccessful attempts to resuscitate and control hemorrhage in 13 patients, 1 of whom was placed on portable pump bypass. Thirty-two patients survived resuscitation and operation, and 26 were long-term survivors. Among surviving patients with permanent paraplegia, 2 underwent pump bypass and 1, the clamp/repair technique. Four other patients were seen with paraplegia or paresis and had reversal of the paralysis. The clamp/repair technique was used in these patients with clamp times ranging from 35 to 62 minutes (mean, 47.4 +/- 13.3 minutes). Renal failure did not occur in any patient, despite clamp times of up to 62 minutes (mean, 37.5 minutes). Excluding patients seen in a moribund condition, mortality most often was secondary to neurological or multisystem injury. Debate continues concerning intraoperative management of this highly lethal vascular injury. The data presented here support the historical composite experience that clamp/repair is a safe and efficacious technique that minimizes paraplegia and mortality.

Surgical experience in descending thoracic aneurysmectomy with and without adjuncts to avoid ischemia

Over the past twelve years, surgical treatment of descending thoracic aneurysms has been performed in 360 patients. Three different operative strategies were employed during resection to provide distal aortic perfusion by temporary bypass (Group 1, 75 patients) or shunt (Group 2, 22 patients) or to simplify the operative procedure with aortic cross-clamping alone (Group 3, 263 patients). The surgical results were determined primarily by patient-related and disease-related variables. Advanced age (older than 70 years), atherosclerotic cause, and emergency operation significantly increased the risks of early mortality and morbidity. The incidence of death (11.7%), paraplegia (6.5%), or renal failure (6%) was not reduced by the use of adjunctive perfusion, and bleeding complications increased significantly in Groups 1 and 2. Spinal cord injury was increased significantly by emergency operations, cross-clamp times exceeding 30 minutes, and extensive aneurysms (p less than 0.05). The risk of renal failure was increased by advanced age and atherosclerotic cause (p less than 0.05). With an experienced surgical team, the primary risks of descending thoracic aneurysmectomy are not influenced by the method of adjunctive perfusion, but are determined by patient factors such as the nature and extent of the aneurysm.

Surgery of thoracoabdominal aortic aneurysms

Arteriosclerotic aneurysm of the thoracoabdominal aorta, involving one or more visceral branches, was successfully operated on in eight patients. Two of the aneurysms had ruptured. The left diaphragm-splitting thoracoabdominal incision through the 8th intercostal space, using a retroperitoneal route, gave unrestricted exposure. A temporary aortofemoral shunt effectively protected abdominal organs and spinal cord from perioperative ischemic damage. The step-by-step reattachment technique into ready-made side limbs in the woven Dacron graft ensured that visceral and renal ischemic times remained within acceptable limits. Perfusion cooling of the abdominal organs was done in one patient in whom shunt could not be used. A standby autotransfusion device was life-saving in another case. All the patients recovered without major complications. Moderate elevation was found as regards serum creatinine levels in seven patients and liver enzymes in four patients, but the values normalized within a month. No paraplegic complications occurred, although all bleeding intercostal and lumbar arteries were ligated intra-aneurysmatically in seven of the eight patients. Seven patients are well 20 to 60 months postoperatively, with patent and well functioning grafts. One patient died of lung cancer after 7 months. Four of the 18 revascularized arteries in three patients were shown by control angiography to be occluded, but without serious sequelae. Our experience suggests that most thoracoabdominal aortic aneurysms are suitable for surgical correction, with acceptable risk. Elective surgery is therefore recommended.

[Use of the TDMAC heparin shunt for operations on the descending thoracic aorta (author's transl)]

This report summarizes our experience with the TDMAC heparin shunt for aortic bypass in descending thoracic aortic surgery. Between 1977 and 1981 twenty-four operations were performed with this shunt (19 men, 4 women, mean age 42 age). Indications for surgery were acute traumatic aortic rupture (6 patients), chronic aortic rupture (6 patients), acute aortic dissection (1 patient), chronic aortic dissection (4 patients), atherosclerotic aneurysms (3 patients), aortic aneurysms combined with PDA (1 patient), aortic aneurysm secondary to coarctation repair (1 patient), and infection of a vascular prosthesis (1 patient). Four patients died (hospital mortality 16.7%). One patient suffered perioperative paraplegia. In this patient the small size (7 mm) shunt hat been used. Therefore we suggest the large bore (9 mm) shunt be applied whenever possible, since even this larger size device displays a significant pressure gradient. When insertion of the shunt into the left subclavian artery is difficult, the ascending aorta or the apex of the left ventricle may be cannulated instead. In our cases we did not encounter any complications arising from shunt cannulation. The advantages of the TDMAC heparin shunt focus on the reduction of bleeding complications more common under systemic heparinization, and on less pronounced hemodynamic and metabolic sequelae following aortic clamping and declamping. With this shunt nearly all possible ischemic organ damage can be avoided.

Cardiopulmonary function following transfusion of three red blood cell products in elective abdominal aortic aneurysmectomy

In order to evaluate the importance of red cell O(2) affinity of transfused blood on cardiac performance and adverse effects of transfusion on lung function, a prospective double-blind protocol was used in 27 patients undergoing abdominal aortic aneurysmectomy. Three types of blood were administered: packed red cells (PC), washed red cells (WC) and high 2,3 DPG red cells (2,3 DPG). An average of 4.5 units of blood was used per patient. Transfusion of 2,3 DPG blood resulted in maintenance of in vivo P(50) during surgery and an increase to 31.2 torr after operation (p < 0.001). An intraoperative fall in in vivo P(50) to 23.2 +/- 2.0 torr was observed in patients who were transfused with PC (p < 0.001) and to 25.1 +/- 2.6 torr with WC (p < 0.005). A fall in body temperature averaging 2.2 C intraoperatively was noticed in all three groups. After operation, in vitro P(50) decreased in patients transfused with PC (p < 0.005) and WC (p < 0.005) while it remained unchanged in the high 2,3 DPG group. This was consistent with the decrease of red cell 2,3 DPG in the PC (p < 0.001) and WC groups (p < 0.01) and maintenance in the 2,3 DPG group. Left ventricular stroke work and volume loading Starling type myocardial performance curves were similar for the three groups. Microaggregates measured by Coulter counting and screen filtration pressure were the same for all three products in samples drawn on both sides of the 40 microm transfusion filter. There was no relationship of transfusion volumes or type of blood product to changes in lung function (physiologic shunting, dynamic compliance and pulmonary arterial pressure) in the three groups of patients. The false negative, beta, error of missing a true 25% difference was less than 10%. It is concluded that 2,3 DPG enriched red cells improved oxygen availability, but that a 4.5 unit transfusion of any of the three blood products did not influence lung function or myocardial performance following aneurysmectomy.

Descending aortic aneurysmectomy without adjuncts to avoid ischemia

Encouraged by reports on the safety of simple aortic cross-clamping for resection of descending aortic aneurysm, we began utilizing this technique more liberally in 1976. This study was undertaken to examine the results of operation in 36 patients, equally divided into two distinct groups. In Group 1, either extracorporeal circulation or indwelling temporary shunts were employed during the period of aortic occlusion. In Group 2, simple aortic cross-clamping was utilized to manage the lesion. No adjuncts were used to avoid ischemia in the latter group. The only 2 early deaths and two instances of paraplegia occurred in Group 1. In general, there were fewer complications in Group 2, with approximately two-thirds of the patients experiencing an uneventful postoperative course. These differences are considered important since the two groups were similar in respect to the extent and nature of the lesions and other factors contributing to operative risk.

Aortic aneurysm repair. Reduced operative mortality associated with maintenance of optimal cardiac performance

Recent advances in the operative management of aortic aneurysms have resulted in a decreased rate of morbidity and mortality. In 1972, we hypothesized that a further reduction in operative mortality might be obtained with controlled perioperative fluid management based on data provided by the thermistor-tipped pulmonary artery balloon catheter. From 1972 to 1979 a flow directed pulmonary artery catheter was inserted in each of 110 consecutive patients prior to elective or urgent repair of nonruptured infrarenal aortic aneurysms. The slope of the left ventricular performance curve was determined preoperatively by incremental infusions of salt-poor albumin and Ringer's lactate solution. With each increase in the pulmonary arterial wedge pressure (PAWP), the cardiac index (CI) was measured. The PAWP was then maintained intra- and postoperatively at levels providing optimal left ventricular performance for the individual patient. There were no 30-day operative deaths among the patients in this series and only one in-hospital mortality (0.9%), four months following surgery. The five-year cumulative survival rate for patients in the present series was 84%, a rate which does not differ significantly from that expected for a normal age-corrected population. Since the patient population was unselected and there were no substantial alterations in operative technique during the present period, these improved results support the hypothesis that operative mortality attending the elective or urgent repair of abdominal aortic aneurysm can be minimized by maintenance of optimal cardiac performance with careful attention to fluid therapy during the perioperative period.