Total replacement of the transverse aortic arch with the Gott aneurysm shunt

A new method of temporary external shunting for total replacement of the aortic arch is described. Its greatest advantage is that systemic heparinization is not required. In a 46-year-old man total body perfusion was achieved with two 9-mm Gott aneurysm shunts inserted between the ascending aorta and both femoral arteries. 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 both carotid arteries. The total cardiac output, measured at 4.7 L/min by the thermodilution technique through a Swan-Ganz catheter, was propelled through these preheparinized multibranch shunts. A flowmeter adapted on one of the 9-mm Gott shunts demonstrated a shunt flow of 2000 ml/min and it was deduced that the other 2700 ml of the total cardiac output was delivered by the other shunt. During the 29 minutes of cross-clamping, there was no change in the filling pressure of either the right heart (central venous pressure 5 cm H2O) or the left heart (pulmonary wedge pressure 8 mm Hg). Aortic continuity was reestablished with the interposition of a 34-mm tubular woven Dacron prosthesis, on which two 10-mm woven Dacron side branches were anastomosed to the innominate and left common carotid arteries. The patient had no neurologic deficit and had normal physiologic function of all other organs.     

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.     

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.)     

Surgery of the descending thoracic aorta: spinal cord protection with the Gott shunt

From July, 1974, to July, 1987, surgical treatment of descending thoracic aortic aneurysms was performed in 173 patients at l'H?pital du Sacré-Coeur de Montréal. The cause of the aneurysms was arteriosclerosis or medial degeneration in 83 patients, trauma in 50, dissection in 34, and a congenital malformation in 6. A single method of external shunting provided distal perfusion in all patients in the series. A 9-mm Gott aneurysm shunt was placed preferentially between the ascending aorta (67%) and the descending aorta (60%). Alternative sites of proximal cannulation (aortic arch, 9%; proximal descending aorta, 22%; left ventricle, 2%) and distal cannulation (abdominal aorta, 3%; left femoral artery, 37%) were chosen based on the location and the extent of the aortic aneurysm. No systemic heparinization was used. In the last 40 patients, a flowmeter adapted for use with the shunt allowed the recording of shunt flow (mean, 2,475 ml/min; range, 1,100 to 4,000 ml/min). Hospital mortality, including patients with ruptured aneurysms, was 15% (26/173). The mean aortic cross-clamp time was 37 minutes (range, 8 to 105 minutes). Of the 173 patients, 168 survived long enough to allow accurate clinical evaluation of the function of the spinal cord: no paraplegia or other spinal cord ischemic injury occurred. To date, our clinical experience has demonstrated the effectiveness of the 9-mm Gott shunt in preserving the functional integrity of the spinal cord during cross-clamping of the thoracic aorta.     

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.     

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.     

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.     

Unusual traumatic rupture of the thoracic aorta with avulsion of the left subclavian artery]

Of the many cases of traumatic rupture of the aorta diagnosed each year at l"H?pital du Sacré-Coeur, Montreal, most patients are already in irreversible shock when seen. However, during the period Oct. 1, 1974 to Sept. 30, 1975, prompt surgical treatment saved six patients. One of these six patients had a complete trans-section of the aortic arch between the left carotid and left subclavian arteries with avulsion and slight retraction of the left subclavian artery. Repair of the aortic arch and left subclavian artery was accomplished without extracorporeal circulation. A sutureless temporary bypass shunt was created by (a) cannulating the ascending and descending aorta, the cannulas being secured with purse-string sutures and joined by a 3/8-inch (94-mm) polyvinyl chloride (PVC) tube connected to a "double T" adapter, and (b) joining two small PVC tubes from the adapter with two straight cannulas, a no. 14 being inserted into the innominate artery and a no. 12 being inserted into the left carotid artery. With this temporary bypass created, the ascending and descending aorta and aortic arch vessels were all clamped. Aortic continuity was re-established with a tubular Dacron graft (diameter, 19 mm) to which was anastomosed a side-arm of knitted Dacron (diameter, 10 mm) to repair the left subclavian artery. Throughout the temporary perfusion the brain, spinal cord and all abdominal viscera were well protected. No sign of ventricular distension was detected. This report is the first in which complete transsection of the aortic arch has been managed by a sutureless bypass shunt allowing perfusion of all aortic arch vessels without extracorporeal circulation.     

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.     

Nonpenetrating trauma to the thoracic aorta

Twenty-seven patients underwent surgical repair for nonpenetrating injuries of the thoracic aorta. Emergency operation was performed in 19 patients with acute aortic injury and there were 12 survivors. Left heart bypass (LHB), external shunts, and simple aortic cross-clamping were methods employed during repair. All operative deaths occurred in the left heart bypass group. Morbidity, hospital stay, operative time, and blood loss all were markedly less in patients repaired with an external shunt or simple cross-clamping. Systemic heparinization related adversely to mortality and morbidity. Eight patients had repair of chronic post-traumatic descending aortic aneurysms. One of these had previous repair elsewhere with paraplegia and subsequent mycotic aneurysm at the graft repair site. He presented to us with massive hemoptysis. Surgical correction in the chronic group was performed using either left heart bypass, external shunt, or simple aortic cross-clamp with graft interposition. The only death occurred in a patient repaired on left heart bypass.     

Spinal cord ischemia following operation for traumatic aortic transection

The danger of irreversible ischemic damage to the spinal cord following repair of traumatic aortic rupture has prompted many techniques designed to decrease this risk. Surgical repair was performed on 41 consecutive patients, using four different methods. These included: group 1 (15 patients), left-heart pump bypass with systemic administration of heparin; group 2 (7 patients), heparinized shunt from the ascending aorta to the descending aorta or to the femoral artery; group 3 (14 patients), heparinized shunt from the left ventricle to the aorta or femoral artery; group 4 (5 patients), aortic cross-clamp only. Spinal cord ischemia was not seen in groups 1 or 2, but paraparesis or paraplegia developed in 4 patients in group 3. Severe shock accompanied rupture in all patients in group 4, and no time was taken for a shunt or bypass. Four of the 7 deaths occurred in the operating room in patients who had arrived moribund and in severe shock. In our experience, shunts from the left ventricle to the aorta have failed to protect the spinal cord against ischemia. Left-heart bypass or aorta-to-aorta shunts are now our procedure of choice.     

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.     

Saphenous vein homograft: a superior conduit for the systemic arterial shunt in the Norwood operation

BACKGROUND: Excessive pulmonary blood flow increases ventricular volume work in the face of inadequate systemic cardiac output, low diastolic blood pressure, and inadequate coronary perfusion. Using the smallest available 3-mm polytetrafluoroethylene shunts have been successful, although catastrophic shunt thrombosis has occasionally been observed. To avoid thrombosis with a smaller conduit, saphenous vein homografts (SVG) were used to construct the modified Blalock-Taussig (BT) shunts. METHODS: From January 1998 to April 1999, 25 patients weighing 3.1 kg (3.0 kg or less, n = 9), at a mean age of 8.9 days, underwent stage I Norwood using an SVG BT shunt. Common heart defects were aortic atresia (n = 8), mitral atresia and double-outlet right ventricle (n = 5), and unbalanced AVC (n = 5). Mean BT shunt size was 3.2 mm, with 12 patients having shunts that were 3 mm or smaller. RESULTS: Thirty-day hospital mortality was 8% (2 of 25). No shunt thrombosis was seen, despite banding the BT shunt in 3 patients. One patient had BT revision because of an anatomic issue not directly related to the shunt material. CONCLUSIONS: Excellent results may be achieved using SVG BT shunts in the Norwood operation. This conduit seems less likely to thrombose, both acutely and chronically, allowing the use of appropriately smaller-sized shunts in small neonates.     

选择性肋间动脉灌注在降主动脉手术中的应用

目的 探讨选择性肋间动脉灌注在降主动脉手术中对脊髓的保护作用.方法 2007年8月至2009年3月,5例降主动脉夹层和2例降主动脉瘤病人行降主动脉置换术.术中保留置换降主动脉上所有肋间动脉,进行选择性肋间动脉灌注,以减少脊髓缺血时间及程度以达到脊髓保护的目的 .术后早期观察和中期随访是否有截瘫发生.结果 术中脊髓缺血23～27 min,平均(24.8±1.6) min.7例术后均未发生截瘫,治愈出院.随访1～19个月,全组无截瘫,生活质量良好.结论 选择性肋间动脉灌注可缩短脊髓缺血时间和程度,脊髓保护效果良好,并可大大降低手术操作难度.     

Thoracic and thoracoabdominal aneurysm repair under deep hypothermia using subclavian arterial perfusion

BACKGROUND: Hypothermic circulatory arrest is a valuable adjunct for thoracic and thoracoabdominal aortic aneurysm repair. Retrograde aortic perfusion through the femoral artery, however, carries a risk of cerebral embolism or malperfusion. To avoid these complications we adopted antegrade aortic perfusion through a prosthetic graft attached to the left subclavian artery through a left thoracotomy. METHODS: Ten patients had repair of descending thoracic and thoracoabdominal aortic aneurysm under deep hypothermia with antegrade aortic perfusion through the left subclavian artery. Hypothermic circulatory arrest was used because proximal aortic control was hazardous due to rupture or intraluminal disease, or for spinal cord protection. RESULTS: There was no brain injury and one hospital death. The cause of death was massive bleeding from the gastrointestinal tract not related to deep hypothermia or the perfusion method. All 9 survivors were alive and well after a mean follow-up period of 9 months. CONCLUSIONS: Using the left subclavian artery as a site of aortic perfusion can avoid retrograde aortic perfusion, hence reducing the potential for brain injury due to embolic stroke or malperfusion through a dissected thoracoabdominal 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.     

A centrifugal pump for graft replacement of the descending thoracic or thoraco-abdominal aorta

Between January 1987, and December 1988, 14 cases of descending thoracic or thoraco-abdominal aortic aneurysm underwent operation using a prosthetic graft replacement. In order to avoid hypoperfusion to distal organs and proximal hypertension during aortic cross-clamping, two different adjuncts were used and the effectiveness of those methods were compared according to the results of surgery. Seven patients were treated with a temporary shunt of heparin-bonded tube from the left axillary artery to left femoral artery, or else Dacron vascular prosthesis from right axillary artery to right femoral artery (Group I). In Group II (seven patients), left heart bypass was performed, using a centrifugal pump from the left atrium to the left femoral artery with minimal heparinization. In Group I, there were two hospital deaths, due to respiratory and hepatic failure respectively, and paraplegia has occurred in one case. In Group II, there was no death during a post-operative observation period of 5-15 months, and there was no case of paraplegia. We think that temporary left heart bypass with a centrifugal pump seems to be the most useful method today for graft replacement of the descending thoracic or thoraco-abdominal aorta.     

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.     

Adequacy of ascending aorta-descending aorta shunt during cross-clamping of the thoracic aorta for prevention of spinal cord injury

The effectiveness of various sized shunts placed between the ascending and the descending aorta to prevent paraplegia in dogs with the thoracic aorta cross-clamped for 1 hour was tested. Three tapered shunts sizes were used with tip dimensions of 3.8, 5.2, and 6.3 mm inner diameter, with cross-sectional areas of 11.34, 21.23, and 33.18 mm2, respectively, and with an equal midportion diameter of 10 mm (3/8 inch). These shunts carried 40%, 60%, and 72% respectively, of baseline descending aortic flow during the cross-clamping period. Flow distribution was measured with radioactive microspheres in the spinal cord (gray and white matter) and kidneys. All dogs without shunts (Group I) developed paraplegia, severe proximal circulatory embarrassment, and severe ischemia of the spinal cord (mainly gray matter) that was followed by marked hyperemia persisting up to 24 hours following the experiment. Mortality was 33%. Only animals treated with large shunts (Groups III and IV) avoided paraplegia and postischemic injury. An effective shunt was characterized as carrying 60% or more of baseline descending aortic flow, having a cross-sectional area at its tip equal to or larger than 29% of the descending aorta, and equaling at least 54% of its diameter. Porportionately, the size of the tridodecylmethylamonium-heparin shunts being used in human beings (even the largest 9 mm inner diameter) is significantly inadequate to maintain distal flows and pressures for the prevention of spinal cord injury. Four clinical options are discussed.     

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.