Descending thoracic aortic aneurysms: surgical treatment with the Gott shunt.

Over the past 16 years, 267 consecutive patients underwent surgery for a descending thoracic aortic aneurysm. To provide optimal protection of surrounding organs during aortic occlusion, a 9-mm Gott shunt was used for distal perfusion in all cases. The shunt was placed preferentially between the ascending aorta and the descending aorta; however, alternative sites of proximal and distal cannulation were chosen according to the location and the extent of the aneurysmal disease and the presence of a concomitant aneurysm along the aortic conduit. In one-third of the patients, a flowmeter on the shunt recorded shunt flows, which varied from 1100 mL/min to 4900 mL/min (mean 2526 mL/min). Because the highest shunt flows were obtained with proximal systolic pressures lower than 140 mm Hg, nitroglycerin and nitroprussate were used routinely to improve distal perfusion by arterial vasodilation and release of proximal organs from a circulatory overload. The mean aortic cross-clamp time was 33 minutes for the entire series but was reduced to 25 minutes for the last 140 patients. The hospital death rate was 14.6% overall (12.2% if ruptured aneurysms were excluded). Of the 267 patients, 260 survived the operation and underwent clinical neurologic assessment. No paraplegia or other spinal-cord ischemic deficit occurred.     

Use of the Gott shunt in the prosthetic replacement of the aortic arch]

Our previous experience in 272 consecutive cases of descending thoracic aortic aneurysms resected without paraplegia by using the 9 mm Gott shunt encouraged us to apply the same technique to more complex aortic surgery. Graft replacement of the transverse aortic arch with brachio-cephalic vessel reattachment was undertaken in 2 patients without the aid of extracorporeal circulation and without systemic heparinisation. Body perfusion was achieved with two 9 mm Gott shunts inserted between the ascending aorta and both femoral arteries. A 10 mm graft interposition between the shunts and the femoral arteries allowed for retrograde perfusion and distal leg irrigation. Blood supply to the brain was maintained with the cut halves of a 7 mm Gott shunt connected as side branches to one of the 9 mm shunts, allowing cannulation of the innominate ant the left carotid arteries. In 90 of the 272 patients treated for a descending aortic aneurysm, a mean shunt flow of 2526 ml/min. was recorded through the 9 mm Gott shunt and from there, we took for granted that the total cardiac output, in there 2 patients, could be propelled by using 2 shunts. During aortic cross clamping, there were no change in the filling pressure of either the right heart or the left heart, and no metabolic acidosis was observed. Both patients survived with normal physiological function of all organs including the brain and the spinal cord.     

Aneurysms of the descending thoracic aorta: Three hundred sixty-six consecutive cases resected without paraplegia

Purpose: The aim of this study was to present a 20-year experience with a single method of passive distal perfusion during descending thoracic aortic aneurysm resection.Method: Aortic repair with a Dacron graft interposition was performed for 366 consecutive aneurysms located between the left subclavian artery and the crux of the diaphragm. The extent of aorta resected in 335 patients (91.5%) represented one third or less of the aortic length. A 9 mm Gott shunt was cannulated proximally into the ascending aorta (235 cases), the aortic arch (60 cases), the descending aorta (68 cases), or the left ventricle (3 cases) and inserted distally into the descending aorta (232 cases), the femoral artery (127 cases), or the abdominal aorta (7 cases). Shunt flows were recorded in 91 cases and varied from 1100 ml to 4900 ml/min, (mean 2526 ml/min). Distal pressure during shunting was measured in 62 patients. It varied from 15 to 120 mm Hg (mean 64.5 mm Hg). The aortic cross-clamp time varied from 8 to 124 minutes (mean 30 minutes).Results: The hospital death rate was 12% overall and 9.9% (35/351) if ruptured aneurysms are excluded. Among 359 operating room survivors, neither immediate nor delayed ischemic spinal cord deficit occurred. Transient renal dysfunction occurred in nine patients (2.4%) and kidney failure in one (0.2%). Five deaths (1.3%) were shunt related.Conclusion: Distal perfusion with the 9 mm Gott shunt has proven to be an effective method to preserve spinal cord function. The limited extent of aorta resected and the brief aortic cross-clamp time may also be interactive factors of protection. (J VASC SURG 1995;21:385-91.)     

Circulatory support during crossclamping of the descending thoracic aorta. Evidence of improved organ perfusion

The need to support the distal circulation during aortic crossclamping and the subsequent effects on hemodynamics and organ perfusion prompted our review of 51 patients who underwent repair of aneurysm of the descending thoracic aorta from 1983 through 1987. Forty-three patients had aneurysms originating distal to the left subclavian artery, and eight had aneurysms involving the distal aortic arch and the proximal descending aorta; 10 patients had emergency operation for aneurysm rupture. Three different techniques were used: Seventeen patients had left atrial-distal aorta arterial bypass with a centrifugal pump, 18 patients had a Gott shunt, and 16 patients had no circulatory support during aneurysm repair. Location and type of aneurysm, age, sex, diabetes, preoperative hypertension, and serum lipid levels were similar in the three groups. Duration of crossclamping was 54 +/- 12 minutes for left atrial-aortic assist, 45 +/- 5 for the shunt group, and 34 +/- 4 for patients without circulatory support. With crossclamping, all groups had similar and significant increases in heart rate (p less than 0.03). Proximal systolic blood pressure did not change during left atrial-aortic assist, but a transient increase occurred in patients with shunts (p less than 0.01), and a sustained increase occurred in patients without circulatory support (p less than 0.05). With crossclamp release, arterial pH and capillary pulmonary wedge pressure decreased significantly (p less than 0.05) in patients without shunt or bypass. Postoperative renal function did not vary significantly when circulatory support was used, but serum creatinine rose transiently in patients with unsupported aortic crossclamping. We conclude that support of the distal circulation during thoracic aortic crossclamping stabilizes hemodynamics and prevents systemic acidosis and renal ischemia. Further, our data suggest that the centrifugal pump may provide better protection than a passive shunt.     

Aneurysms of the aortic arch. Experience of 19 cases]

From 1980 to 1990, 19 consecutive patients were operated for chronic aneurysm of the aortic arch: 16 men and 3 women with a mean age of 46 years (range: 20 to 72 years). Four aneurysms were proximal, with a distal limit in the left common carotid artery; 4 were distal, starting beyond the brachiocephalic trunk and 11 involved the entire aortic arch. Three were atheromatous, 9 were dystrophic, 1 was syphilitic, 1 was post-traumatic, 1 was secondary to coarctation and 4 was secondary to longstanding dissection. Four cases (21%) were in a state of pre-rupture. They were all operated under cardiopulmonary bypass with profound hypothermia and circulatory arrest in 11 cases (9 cases of aneurysm involving the entire segment II and two cases of distal aneurysms). Selective cannulation of the large cervical arteries supplying the brain was performed in 5 cases (3 cases of proximal aneurysms and 2 cases of aneurysms of the entire segment II). Seven patients simultaneously underwent aortic valve replacement and replacement of the ascending aorta. One patient underwent replacement of the descending aorta and another underwent an ascending aorta-supracoeliac aorta bypass graft. The early mortality was 10.5% (2 patients out of 19) and the late mortality was 5.8% (1 patient out of 17). The mean follow-up was 46 months (maximum: 9 years, minimum: 9 months), and the 9-year actuarial survival rate was 86%. This study demonstrated the superiority of selective carotid cannulation as a means of cerebral protection.     

Repair of lesions of the descending thoracic aorta with the TDMAC-heparin shunt

Utilizing a heparinized tridodecylmethylammonium chloride (TDMAC) shunt makes it possible to treat various surgical diseases of the descending thoracic aorta without cardiopulmonary bypass. Since the initial report by Gott and associates on the use of the heparinized shunt, few subsequent clinical trials have appeared in the literature. Six patients with Type III dissecting thoracic aneurysm, acquired and congenital coarctation of the aorta, saccular arteriosclerotic aneurysm, and transection of the descending thoracic aorta were operated upon by means of this technique. Only one patient had more than 500 ml. of chest tube drainage in the first 8 hours postoperatively. There were no instances of paraplegia, renal failure, or death. This technique is also recommended for repair of innominate artery aneurysms, endarterectomy of the innominate or subclavian artery, arch aneurysm, penetrating injuries of the thoracic aorta, and proximal abdominal aneurysms. Surgical indications, operative management, and postoperative follow-up are discussed.     

The use of the TDMAC-heparin shunt in replacement of the descending thoracic aorta.

The use of a flexible polyvinyl tube bonded with tridodecylmethylammonium-heparin (Gott) as a temporary shunt during the resection of lesions of the descending thoracic aorta has proven a safe and simple means of providing adequate circulation to the abdominal viscera and spinal cord. This technique avoids the metabolic consequences of ischemia to the lower body, diminishes left ventricular afterload during aortic clamping, and obviates the requirement for systemic anticoagulation associated with pump bypass. Between September 1970 and October 1974, 24 patients have been operated using the TDMAC shunt. There were two deaths (9%) among the 22 patients undergoing elective resections. Two patients with acutely dissecting and ruptured aneurysms expired. Followup data has been obtained on all patients from one to 46 months postoperative. The ease with which the shunt is inserted and its adaptability to varied clinical and anatomic situations is stressed. We feel that TDMAC-Heparin shunt provides the best method of circulatory support for elective operative procedures on the descending thoracic aorta.     

Acute dissection of the descending thoracic aorta: repair in an unusual case

Acute tamponade, although a rare manifestation of a descending thoracic aneurysm, was the dominant clinical feature of a classic type III dissecting aneurysm (arising distal to the left subclavian artery) in a 52-year-old man. High-quality aortography confirmed the diagnosis, ruling out any anomaly of the ascending aorta and the aortic arch. Surgical treatment was carried out 24 hours after the initial episode without cardiopulmonary bypass. Through a left thoracotomy, a Gott shunt was inserted proximally at the apex of the left ventricle and distally in the left femoral artery. Aortic repair with the interposition of a 30-mm woven Dacron prosthesis was successful. Postoperative aortography showed complete restoration of aortic integrity.     

Arterial Shunt with Pump Infusion Line for the Treatment of Chronic Thoracic Aortic Aneurysms: The "Modified Shunt of Gott"

Dissection of the aneurysm is the most dangerous step during graft replacement of the descending thoracic aorta. Sudden hemorrhage may follow wall rupture or disruption of major collaterals before the aorta can be clamped. A simple modification of the classic Gott is illustrated, which makes the shunt work also as a partial bypass if needed, with rapid reinfusion of blood losses. Nineteen of 25 patients requiring resection of descending aortic aneurysms from 1982 to 1990 were treated with this method with no mortality.     

Fate of aneurysms of the distal arch and proximal descending thoracic aorta after transaortic endovascular Stent-Grafting

BACKGROUND: The purpose of this study was to evaluate the midterm results of transaortic stent-grafting for distal aortic arch aneurysms or proximal descending aortic aneurysms and the feasibility of this method for thoracic aortic aneurysm repair. METHODS: Twenty-three patients with true distal aortic arch aneurysms or proximal descending thoracic aortic aneurysms were repaired with the stent-graft introduced through the incision on the proximal arch aorta. Follow-up computed tomography was performed every 6 months in 21 surviving patients. The maximum dimension of the excluded aneurysmal space and the maximum aneurysmal diameter were measured and evaluated to determine whether the aneurysmal space decreased or disappeared after this alternative procedure. RESULTS: There was 1 hospital death (4.3%) due to cerebral embolism. Another patient died of pneumonia 1 year after surgery. Twenty-one patients (91%) survived during the follow-up period, but 1 patient (4.3%) suffered from paraplegia. The follow-up period ranged from 12 to 62 months (average, 34.3 +/- 15.2). There were no instances of aneurysmal rupture during the follow-up period. Postoperative serial computed tomography scans showed disappearance or significant shrinkage of the excluded aneurysmal space in 20 of 21 patients (95%), except for the one patient with endoluminal leakage. CONCLUSIONS: Transaortic endovascular stent-grafting was an effective alternative approach to treating distal aortic arch aneurysms or proximal descending aortic aneurysms. The excluded aneurysm disappeared or shrunk after successful placement of the stent-graft.     

Exclusion-bypass for aneurysms of the descending thoracic and thoracoabdominal aorta

From October 1973 to April 1985, 81 patients with aneurysms of the descending thoracic or thoracoabdominal aorta underwent surgery. Eight (10%) of these patients were treated by exclusion-bypass. The aneurysm was located in the descending aorta alone in five cases, and in the descending thoracic and thoracoabdominal aorta in three cases. In all cases, the proximal anastomosis of the bypass was performed on the ascending aorta. The site of the distal anastomosis was the supraceliac aorta in two cases, the infrarenal aorta in three cases and the iliac arteries in three other cases. Exclusion was bipolar, at each end of the aneurysm, in six cases, and unipolar, ie. proximal interruption only, in two cases. Two patients died during the first postoperative month, one of rupture of the distal portion of the aortic arch, the second, after onset of secondary paraplegia. There were no other spinal, cardiac or cerebral complications. One patient died three months postoperatively of intercurrent pulmonary infection. The five other surviving patients whose mean follow-up period is 48.1±25 months, are alive and enjoying good health. Resection and grafting as advocated by Crawford, is the usual treatment proposed for aneurysms of the descending thoracic and thoracoabdominal aorta. Exclusionbypass may however be preferred in the following cases: elderly patients with compromised respiratory status, aneurysms of the descending thoracic aorta, either voluminous, of infectious origin or associated with aneurysm of the infrarenal abdominal aorta.     

Acute and chronic traumatic aneurysms of the descending thoracic aorta: a 10-year experience with a single method of aortic shunting

A 10-year experience in the surgical treatment of traumatic aneurysms of the descending thoracic aorta is reviewed. This series included 40 patients equally divided into two groups. Group I comprised 20 acute ruptures and group II, 20 chronic traumatic aneurysms, all situated at the aortic isthmus. The surgical repair was performed in all patients with a single method of aortic shunting. A Gott aneurysm shunt was used as a temporary external bypass between the ascending and the descending aorta, giving priority to organ protection during aortic cross-clamping. The survival rate was 95% (38/40). The two deaths occurred in the acute group and were related to severe brain trauma present before surgery. The aortic cross-clamping time averaged 43 minutes. Regarding organ protection, no brain damage, no heart failure, no renal dysfunction, and no paraplegia occurred. These results emphasize the safety and the reliability of this shunting procedure.     

One-staged operation for multiple aortic aneurysms of the descending thoracic aorta and abdominal aorta; report of a case

A 66-year-old man underwent successfully on one-staged operation for aneurysms of the descending thoracic aorta and abdominal aorta. For the operation of descending thoracic aortic aneurysm, a temporary bypass was used from the proximal side of aneurysm to the distal one. The sacculer aneurismal wall of the descending thoracic aorta was repaired by patch formation using a knitted graft. Abdominal aortic aneurysm was replaced using a Gelsoft graft. The operation time was 7 hours and 35 minutes. Blood transfusion was not needed. The postoperative course was uneventful. It is suggested that one-staged operation for descending thoracic aortic aneurysm under the assist of temporary bypass and abdominal aortic aneurysm is possible.     

Prevention of paraplegia secondary to operations on the aorta

Prevention of paraplegia during operations on the aorta requires knowledge of the blood supply to the spinal cord. The great radicular artery of Adamkiewicz (RAD) plays a major role in the supply to the anterior spinal artery which nourishes the anterior two-thirds of the cord. The RAD usually arises from an intercostal artery between T9-T12 but may arise higher or in 10% of patients from a lumbar artery. Temporary interruption of flow by crossclamping, hypotension, or permanent interruption of the RAD are factors in the etiology of paraplegia. In resection of descending thoracic aortic aneurysms, the thoracic aorta should not be crossclamped without an external bypass. The bypass should be nonthrombogenic to avoid necessity for anticoagulation and attendant hemorrhagic problems. Bypass flow is ideally controlled by a pump with continuous monitoring of the proximal and distal pressures to provide normal distal flow to the cord. As many intercostal and high lumbar arteries as possible should be preserved by retaining the distal posterior wall of the aneurysm. Preoperative selective catheterization of the distal thoracic intercostal or proximal lumbar vessels can delineate critical supply to the cord and should become part of the routine workup of patients being considered for surgery of the distal thoracic and thoraco-abdominal aorta. Knowledge of the location of the RAD may permit its avoidance or reinsertion into a graft. Avoidance of the RAD may be particularly applicable with infrarenal aneurysms when a large lumbar artery is seen just above or below a renal artery. Here, avoidance of all but brief suprarenal clamping and resection of the aneurysm below the feeding RAD may help to avoid paraplegia.     

Thromboembolism from undersized Dacron grafts in the descending thoracic aorta

Three patients were referred to our institution for major thromboembolic complications secondary to the use of undersized Dacron grafts (14, 16, and 18 mm) in the descending thoracic aorta. The progressive accumulation of thrombotic material in the prosthesis caused recurrent coarctation in 1 patient and peripheral embolisms in the other 2. With a 9-mm Gott shunt providing distal perfusion, excision of the clotted graft and its replacement with a 22-mm Dacron prosthesis was successfully achieved in each patient.     

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.     

Beneficial Circulatory Support by Left Heart Bypass with a Centrifugal (BioMedicus) Pump for Aneurysms of the Descending Thoracic Aorta

Abstract: A comparative study between left heart bypass with a centrifugal (BioMedicus) pump and with a temporary external shunt was performed to assess the efficacy of distal organ perfusion in the surgical treatment of 31 patients with aneurysm of the descending thoracic aorta. Eighteen patients were supported with a centrifugal pump, and the remaining 13 were supported by temporary shunt with either a Gott shunt or a Dacron graft. Heparinless bypass with a centrifugal pump provided a significant decrease of intraoperative blood loss and blood transfusion by the combined application of Cell-Saver. The pressure difference between upper and lower extremities decreased (p < 0.05) in the centrifugal pump group even with aortic cross-clamping, and the urine output increased during operation. Among 13 patients supported with the temporary shunt, 3 had postoperative renal failure, and 2 died of it. All patients with a centrifugal pump survived without any complications. It could be concluded that the left heart bypass with a centrifugal (BioMedicus) pump was safe and was favorable for support of the distal circulation during aortic cross-clamping and to prevent ischemic complications such as renal failure and spinal cord injury.     

Early and late results following repair of dissections of the descending thoracic aorta

Management of dissections of the descending thoracic aorta remains controversial, especially with regard to timing and method of repair. To clarify these and other issues we have reviewed our total experience with repair of descending aortic dissections between 1962 and 1983. The 44 men and 20 women had a mean (+/- SEM) age of 59 +/- 2 years (range, 19 to 83 years), and in all patients the dissection originated in and was limited to the aorta distal to the left carotid artery (Stanford type B, DeBakey types IIIa and IIIb). Twenty-nine patients underwent operation within 2 weeks of the onset of symptoms (acute), and the remainder had later repair (chronic). During repair, circulation distal to the aortic cross-clamp was supported with cardiopulmonary bypass or shunt in two thirds of patients. Overall, 18 deaths occurred less than or equal to 30 days postoperatively (operative risk 28%), and risk was higher in acute (45%) than in chronic (14%) dissections. Operative risk was not significantly related to protection of the distal circulation. The most serious postoperative complication was spinal cord ischemia manifested by paraplegia in five patients (8%) and transient or permanent paraparesis in six patients (9%). Risk of spinal cord ischemia was significantly lower in patients who had protection of the distal circulation during operative repair (8% vs. 44%, p = 0.003). Late survival, including hospital deaths, was 49% +/- 7% at 5 years after operation; 22 of the 46 patients who survived repair were found to have aneurysms involving the thoracic and/or abdominal segments of the aorta. Our results indicate that repair of chronic dissection of the thoracic aorta has a lower operative risk than repair of acute dissections, and initial medical management of acute dissection may be indicated if no early complications occur. Risk of spinal cord ischemia is significantly reduced by cardiopulmonary bypass or shunt and is preferred over aortic cross-clamping alone. Finally, these patients require careful long-term follow-up because of the high incidence of residual or recurrent aortic aneurysms.     

Partial cardiopulmonary bypass, hypothermic circulatory arrest, and posterolateral exposure for thoracic aortic aneurysm operation

Partial cardiopulmonary bypass, profound hypothermia, and circulatory arrest were used in the treatment of 25 patients with thoracic aortic aneurysms exposed through left posterolateral incisions. Indications included aortic clamp laceration (4 patients), pulmonary artery tear (1), treatment of ruptured aneurysm without clamping (5), right-sided arch (2), exposure of proximal aorta in a patient with a large aneurysm (1), inability to expose the proximal aorta for clamping (3), to permit removal of both arch and distal aorta (4), and to avoid distal arch clamping because of atheromatous disease (5). Aortic segments ranging from the upper descending thoracic aorta to most of the aorta were replaced, with early survival in 21 patients. Cerebral protection was satisfactory.     

Aneurysms of the descending aorta. Surgical experience in 48 patients

Uniformity of opinion does not exist concerning an optimal surgical strategy for descending aortic aneurysms. In order to assess the impact of surgical technique on operative mortality, morbidity, late outcome, we reviewed 48 consecutive patients operated upon from 1976 to 1980. Average age was 61 years, and 37 patients (77%) were men. The average interval of aortic occlusion in the Gott shunt group was 48 minutes, which was significantly longer than that of patients operated upon without shunts (30 minutes). No patient in the Gott shunt group had postoperative paraplegia, but it was noted in two patients (18%) treated without a shunt. Operative deaths in patients with Gott shunts were caused by cardiac (two patients), neurologic (one patient), pulmonary (one patient), and abdominal (two patients) factors. A pulmonary embolus caused the single postoperative death in the "no shunt" group, and another patient died intraoperatively. A group of seven patients were treated by temporary femoral vein--femoral artery bypass because of extensive aneurysmal disease, advanced associated major systemic disorders, or anticipated excessive hemorrhage when the aneurysm was opened. All patients survived free of neurologic sequela, but one developed a reversible intraoperative coagulopathy. This study underscores the safety and usefulness of the femoral vein--femoral artery bypass in treating certain descending thoracic aneurysms and reinforces the importance of several technical guidelines concerning the proper insertion and use of the Gott shunt. These guidelines would have significantly reduced the observed operative morbidity and mortality.