Australas Radio1 1992: 36: 99-101
Thrombolysis and the Femorofemoral Bypass Graft: A New Technique T.M. BUCKENHAM,F.R.A.C.R. ANDC.D. GEORGE, F.R.C.S. Department of Radiology R.S. TAYLOR, M.S., F.R.C.S. AND J.A. DORMANDY, D.Sc, F.R.C.S. Department of VascularSurgery St. George’sHospital, Blackshaw Road, Tooting,London SWI 7 OQT
ABSTRACT Two patients with acutely thrombosed femorofemoral bypass grafts are presented. Recombinant human tissue-type plasminogen activator (rt-PA) was used successfully in thrombolysis of the occluded grafts. Utilizing a new technique the grafts were punctured directly and bolus doses of rt-PA administered. INTRODUCTION The femorofemoral bypass graft is an extra-anatomic bypass graft first introduced in the 1950s and popularised in the 1960s (1). It can be used to treat unilateral limb ischaemia caused by iliac occlusive disease provided that the donor vessel is haemodynamically normal and there is adequate run-off below the groin in the symptomatic leg. It is a safe and relatively simple form of bypass graft which can be performed under local anaesthesia. Although initially used as a salvage procedure in high-risk patients with critical ischaemia, more recently it has been used as an alternative to an aortofemoral graft to treat unilateral claudication (2). In this situation it has the added advantage of
not disturbing the aortoiliac sympathetic plexus which can result in erectile impotence. Long-term patency rates approach those of aortofemoral grafts and it seems likely that more femorofemoral bypass grafts will be performed over the next decade
(3). Thrombolysis for acute limb ischaemia has been carried out since 1960 when the f i s t intravenous use of streptokinase was reported. The use of other thrombolytic agents such as urokinase and rt-PA is now well documented. The intra-arterial route is preferred for the administration of these agents and it has become apparent that technical aspects such as catheter placement and graft access are critical for a good outcome. Thrombosed fernorofemoral bypass grafts are being seen more frequently and the surgical options in these patients may be limited by scar tissue from previous operations, the severity of their peripheral vascular disease and their general medical condition. Consequently increasing numbers are being referred for thrombolytic therapy. We present two cases of femorofemoral bypass graft thrombosis in which direct puncture of the graft and bolus administration of rt-PA facilitated rapid and complete thrombolysis. One patient also had an immediate angioplasty of a stenosis at the distal anastomosis.
MAERIALS AND METHODS Key words: Graft occlusion, vascular Blood vessel prosthesis, adverse effects Plasminogen activator, tissue-type Thrombolytic therapy Arterial occlusive disease Thrombosis, drug therapy Fibrinolytic agents, therapeutic use Address for correspondence: Dr.T.M. Buckenham Department of Radiology St. George’s Hospital Blackshaw Road Tooting London SW17 OQT Australasian Radiology, Vol. 36, No. 2. May. 1992
The subcutaneous position of these grafts on the anterior abdominal wall allows palpation and identification of the approximate position of the proximal anastomosis. The anterior wall of the graft is punctured with an 18 gauge single puncture needle and the intraluminal position confirmed by injection of contrast or the introduction of a J-wire. Once the lumen is accessed a 5 French dilator is introduced and positioned with its tip midway along the graft, embedded in
thrombus. Our protocol requires that 5mg of rt-PA are administered as a 5ml bolus injection over 30 seconds. After a ten minute interval a check angiogram is performed via the dilator and the dilator advanced into any residual thrombus. A maximum of three 5mg boluses of rt-PA are given. Thereafter residual thrombus is lysed using an infusion of rt-PA at a rate of 0.05mgIkghr. Once the graft thrombus is fully lysed then a 5F straight single endhole catheter is exchanged for the dilator and passed distally through the anastomosis into the recipient native artery and thrombolysis continued. Patients are concurrently anticoagulated using systemic heparin at a dose of 20 000IU/24hr. Intravenous antibiotics are also given; Cefuroxime 1.5gm and metronidazole 500mg as single doses at the start of the procedure and continued in a dosage of 75Omg tds and 5OOmg tds respectively for three days. Case I A 70 year old female presented with a three day history of rest pain of acute onset in the left buttock and leg. Two months previously the patient had a successful right to left femorofemoral bypass graft for claudication at 10 yards. Post operatively her claudication distance had increased to 200yds and she had remained well and mobile until readmission. On examination the left foot was pale and cool but viable. The right femoral and popliteal pulses were palpable but neither left femoral nor graft pulsation could be felt.
Submitted forpublication on: 24th May, 1991 Accepted for publication on: 27th August, 1991
99
T.M. BUCKENHAM et a1
FIGURE I situ.
- IniW angiopm showing extensive thrombus in the crOSSOver graft with the catheter in
-
RGURE 2 Digital subascbion angiogmn during the procedure showing partial thrombolysis in the
rn
Emergency intravenous digital subtraction angiography (IV-DSA) showed that the graft and the proximal parts of the left superficial femoral and profunda femoris arteries were occluded. An initial attempt at rt-PA thrombolysis was abandoned because it proved impossible to enter the graft from the right femoral artery. The patient then underwent a surgical thrombectomy performed through a small transverse incision in the middle of the graft. The incision in the graft was sutured with prolene and the wound closed over a suction drain. Unfortunately re-thrombosis occurred almost immediately. The patient was returned to the radiology department and a direct percutaneous puncture of the graft was made close to the anastomosis with the right common femoral artery. Thrombolysis using rt-PA was started according to the protocol described above. Lysis of thrombus within the graft was complete after one bolus of rt-PA. Residual thrombus was identified in the distal vessels. It FIGURE 3 - F d .ngiopm showing completproved impossi ble to place - t h e cd -WsiSlongstanding supficia1 catheter securely into each affected fnwnl artery occlusion is Jeen and poor runvessel in order to administer further off occm via prorunda fnnOri.9. 100
direct bolus doses. The catheter was therefore positioned just beyond the distal end of the graft and rt-PA infused. Interim angiograms showed progressive lysis of the residual thrombus and complete lysis was achieved after 2 hours. The final angiogram showed a stenosis at the distal anastomosis to the left femoral artery. Immediate balloon angioplasty was performed with rapid subjective and objective improvement in the condition of the patient’s left leg. A small haematoma developed around the operative and puncture sites despite local pressure and the total blood loss into the drain was 675m1. The clinical improvement in the left foot was maintained and the patient was discharged three days after the procedure able to walk 50yds. An IV-DSA three weeks after discharge showed the graft to be patent. Case 2 An 83 year old female presented with a three day history of acute left leg claudication at 5 yards. The patient stated that these were her exact symptoms prior to her operation two years previously when a right to left femorofemoral bypass graft was inserted. On examination the left foot was severely ischaemic but viable. The right femoral pulse was palpable but graft pulsation and the left femoral pulse were absent. A direct percutaneous puncture of the graft was made close to the anastomosis to the right femoral artery. An angiogram showed extensive thrombus within the graft (Figure 1). Thrombolysis using rt-PA was performed according to the protocol and interim angiograrns showed progressive thrombolysis (Figure 2). After the third bolus the thrombus was completely lysed (Figure 3). N o focal stenosis or other causative lesion was identified. Following the procedure the patient’s symptoms and signs improved rapidly. The patient remained well at follow-up six weeks after the procedure.
DISCUSSION The acutely thrombosed femorofemoral bypass graft is an uncommon but difficult clinical problem. Many patients with such grafts have advanced arterial disease and have had extensive previous surgery which makes the surgical management difficult. The method of graft access and thrombolysis we describe is novel and based on modifications of established techniques (4,s). We have been unable Australasian Rodiolog,~.Vol. 36. No. 2 . May. 1992
THROMBOLYSIS AND THE FEMOROFEMORAL BYPASS GRAFT to find any reports of femorofemoral graft thrombolysis in the radiological or surgical literature and direct graft puncture in this situation is not a documented technique. Lack of backflow from the thrombosed graft makes the determination of needle position more difficult than usual. However, most femorofemoral grafts lie subcutaneously and are palpable enabling relatively easy access. Subsequent manipulation allows the catheter to be passed through the graft and into the native vessels of the recipient leg. Once the graft thrombus has been lysed the vascular anatomy of the recipient limb can be demonstrated and assessed for stenoses and other factors predisposing to thrombosis. If a suitable lesion is identified then immediate angioplasty can be performed. T h e lack of reports concerning direct graft puncture of extra-anatomic grafts means that there is no information relating to the complications that might arise. However, puncture of aortofemoral grafts is well documented and carries no greater risk of complications than native vessel puncture (6). Clearly the risk of problems will be greatly increased with the employment of fibrinolytic agents but this should not represent a major problem in superficially situated grafts which are easily compressible and accessible to surgical intervention if required. It would be preferable to access the thrombosed graft from the native vessels on the run-in side of the graft. This was attempted in the first case but it proved technically impossible to manoeuvre the catheter through the anastomosis into the graft. A direct puncture was performed only after a failed surgical thrombectomy. In the second case, the initial approach was to puncture the graft percutaneously. It would appear from the results of these two cases that persistent thrombus in the short segment of graft proximal to the puncture site is not a problem. Presumably, either there is sufficient rt-PA reflux proximally to effectively lyse the clot, or, less likely, the small plug of residual thrombus is carried ‘downstream’ by the inflow of blood into the clearing distal graft. It would seem prudent however to puncture the graft as close to the donor artery anastomosis as possible.
The usual anatomical configuration of cross-over grafts makes catheterisation of the origin particularly difficult if not impossible. The same difficulties occasionally arise when attempting to clear occluded femoro-distal grafts. Often there may be no accurate record Australasian Radiology. VoI. 36. No. 2 May. 1592
as to the precise orientation of the graft origin. If no stump is visible on angiography then cannulation may be impossible. In such cases direct puncture of the graft (with limited surgical exposure if required) may be a viable alternative to a major surgical procedure. Our initial experience with this technique is showing promising results. Recombinant tissue type plasminogen activator has been used extensively in peripheral arterial thrombolysis (7-1 1). The advantages of rt-PA are its considerable fibrin specificity, characterized by a high affinity for fibrin bound plasminogen relative to circulating plasminogen. This allows localised conversion of plasminogen to plasmin at the clot interface facilitating effective local thrombolysis and avoiding systemic fibrinolysis (8). Infusion through a catheter or luminal wire embedded in the thrombus is the usual mode of administration of rt-PA. The rate of infusion is usually 0.05- O.lmg/kg/hr and the catheter is repositioned as required. In our hands this technique has resulted in shorter procedure times and more effective thrombolysis of the distal vessels when compared to those achieved using streptokinase. Research has shown that a high dose of rt-PA infused over a short time has less systemic lytic effect, whereas a lower dose infused over a longer period is associated with increased fibrinogenolysis (8). As the duration of infusion increases systemic fibrinolysis increases, resulting in increased systemic lysis. This poses the question whether shorter periods of treatment will decrease systemic lytic activity. Giving rt-PA in a 5mg bolus, up to a maximum of three doses each separated by an interval is an attempt to increase the rate of thrombolysis and to reduce infusion times (5). The 10 minute interval between boluses was selected as the half-life of rt-PA is approximately 5-9 minutes. It has yet to be shown that the bolus technique is better o r safer than conventional infusion techniques and this is the subject of an ongoing joint study between our own department and that of Dr Juhan of Hopital Nord, Marseilles, France. However, many of the complications encountered during thrombolysis are related to the catheter or to systemic thrombolysis and in theory both may be reduced by shortening infusion times.
small haematoma and had a measured loss of 675mls into the surgical drain. The size of this loss is attributable to the incision for surgical thrombectomy performed immediately before the thrombolysis. Thrombolysis was only performed in such circumstances because of a severe deterioration in the circulatory state of the limb and in the knowledge that bleeding could be monitered accurately and flow through the graft arrested if necessary. Losses in the second case were negligible. Patients with acutely thrombosed femorofemoral bypass graft present a complex management problem. Previous vascular surgery may make further surgery difficult and the overall condition of the patients is often poor. In such circumstances bolus administration of rt-PA directly into the graft may be a relatively rapid, effective and safe method of restoring blood flow to the affected limb. REFERENCES 1. Vetto RM. The treatment of unilateral iliac artery obstruction with a transabdominal subcutaneous femorofemoral graft. Surgery 1962; 52: 342-345. 2. Mannick JA, Maini BS. Femorofemoral grafting: indications and late results. Am J Surg 1978; 1 3 6 190-192. 3. Fahal AH. McDonald AM, Marston A. Femorofemoral bypass in unilateral iliac artery occlusion. Br J Surg 1989; 76: 22-25. 4. Sullivan KL, Gardiner GA, Shapiro MJ, Bonn J, Levin DC. Acceleration of thrornbolysis with a high-dose transthrombus bolus technique. Radiology 1989: 173: 805-808. 5 . Juhan C. Haupert S. Miltgen G. Barthelemy P. Intra-arterial infusion of r-TPA. A two stage procedure. J Cardiovasc Surg 1990. 31: 89. 6. Eisenberg RL, Mani RL, McDonald EJ. The complication rate of catheter angiography by direct puncture through aortofemoral bypass grafts. Radiology 1976; 126: 814-816. 7. Graor RA. Risius B. Young JR ef al. Peripheral artery and bypass graft thrombolysis with recombinant human tissue type plasminogen activator. J Vasc Surg 1986; 3: 1 15- 124. 8. Graor RA, Risius B, Lucas FV er al. Thrombolysis with recombinant human tissue-type plasminogen activator in patients with peripheral mery and bypass graft occlusions. Circulation 1986; 74 (suppl I): 15-20, 9. Hess H, Mietaschk A, Bruckl R. Peripheral artery occlusions: a six year experience with local low dose thrombolytic therapy. Radiology 1987: 163: 753-758. 10. Earnshaw JJ, Westby JC, Gregson RHS. Makin GS. Hopkinson BR. Local thrombolytic therapy of acute peripheral arterial ischaemia with tissue plasminogen activator: a dose-ranging study. Br J Surg 1988 75: 1196-1200. 11. Berridge DC. Gregson RHS, Makin GS. Hopkinson BR. Tissue plasminogen activator in peripheral arterial tluombolysis. Br J S U 1990: ~ 77: 179-182.
The commonest complication of thrombolysis is haematoma formation at the puncture site. Case 1 developed a 101
Thrombolysis and the Femorofemoral Bypass Graft: A New Technique T.M. BUCKENHAM,F.R.A.C.R. ANDC.D. GEORGE, F.R.C.S. Department of Radiology R.S. TAYLOR, M.S., F.R.C.S. AND J.A. DORMANDY, D.Sc, F.R.C.S. Department of VascularSurgery St. George’sHospital, Blackshaw Road, Tooting,London SWI 7 OQT
ABSTRACT Two patients with acutely thrombosed femorofemoral bypass grafts are presented. Recombinant human tissue-type plasminogen activator (rt-PA) was used successfully in thrombolysis of the occluded grafts. Utilizing a new technique the grafts were punctured directly and bolus doses of rt-PA administered. INTRODUCTION The femorofemoral bypass graft is an extra-anatomic bypass graft first introduced in the 1950s and popularised in the 1960s (1). It can be used to treat unilateral limb ischaemia caused by iliac occlusive disease provided that the donor vessel is haemodynamically normal and there is adequate run-off below the groin in the symptomatic leg. It is a safe and relatively simple form of bypass graft which can be performed under local anaesthesia. Although initially used as a salvage procedure in high-risk patients with critical ischaemia, more recently it has been used as an alternative to an aortofemoral graft to treat unilateral claudication (2). In this situation it has the added advantage of
not disturbing the aortoiliac sympathetic plexus which can result in erectile impotence. Long-term patency rates approach those of aortofemoral grafts and it seems likely that more femorofemoral bypass grafts will be performed over the next decade
(3). Thrombolysis for acute limb ischaemia has been carried out since 1960 when the f i s t intravenous use of streptokinase was reported. The use of other thrombolytic agents such as urokinase and rt-PA is now well documented. The intra-arterial route is preferred for the administration of these agents and it has become apparent that technical aspects such as catheter placement and graft access are critical for a good outcome. Thrombosed fernorofemoral bypass grafts are being seen more frequently and the surgical options in these patients may be limited by scar tissue from previous operations, the severity of their peripheral vascular disease and their general medical condition. Consequently increasing numbers are being referred for thrombolytic therapy. We present two cases of femorofemoral bypass graft thrombosis in which direct puncture of the graft and bolus administration of rt-PA facilitated rapid and complete thrombolysis. One patient also had an immediate angioplasty of a stenosis at the distal anastomosis.
MAERIALS AND METHODS Key words: Graft occlusion, vascular Blood vessel prosthesis, adverse effects Plasminogen activator, tissue-type Thrombolytic therapy Arterial occlusive disease Thrombosis, drug therapy Fibrinolytic agents, therapeutic use Address for correspondence: Dr.T.M. Buckenham Department of Radiology St. George’s Hospital Blackshaw Road Tooting London SW17 OQT Australasian Radiology, Vol. 36, No. 2. May. 1992
The subcutaneous position of these grafts on the anterior abdominal wall allows palpation and identification of the approximate position of the proximal anastomosis. The anterior wall of the graft is punctured with an 18 gauge single puncture needle and the intraluminal position confirmed by injection of contrast or the introduction of a J-wire. Once the lumen is accessed a 5 French dilator is introduced and positioned with its tip midway along the graft, embedded in
thrombus. Our protocol requires that 5mg of rt-PA are administered as a 5ml bolus injection over 30 seconds. After a ten minute interval a check angiogram is performed via the dilator and the dilator advanced into any residual thrombus. A maximum of three 5mg boluses of rt-PA are given. Thereafter residual thrombus is lysed using an infusion of rt-PA at a rate of 0.05mgIkghr. Once the graft thrombus is fully lysed then a 5F straight single endhole catheter is exchanged for the dilator and passed distally through the anastomosis into the recipient native artery and thrombolysis continued. Patients are concurrently anticoagulated using systemic heparin at a dose of 20 000IU/24hr. Intravenous antibiotics are also given; Cefuroxime 1.5gm and metronidazole 500mg as single doses at the start of the procedure and continued in a dosage of 75Omg tds and 5OOmg tds respectively for three days. Case I A 70 year old female presented with a three day history of rest pain of acute onset in the left buttock and leg. Two months previously the patient had a successful right to left femorofemoral bypass graft for claudication at 10 yards. Post operatively her claudication distance had increased to 200yds and she had remained well and mobile until readmission. On examination the left foot was pale and cool but viable. The right femoral and popliteal pulses were palpable but neither left femoral nor graft pulsation could be felt.
Submitted forpublication on: 24th May, 1991 Accepted for publication on: 27th August, 1991
99
T.M. BUCKENHAM et a1
FIGURE I situ.
- IniW angiopm showing extensive thrombus in the crOSSOver graft with the catheter in
-
RGURE 2 Digital subascbion angiogmn during the procedure showing partial thrombolysis in the
rn
Emergency intravenous digital subtraction angiography (IV-DSA) showed that the graft and the proximal parts of the left superficial femoral and profunda femoris arteries were occluded. An initial attempt at rt-PA thrombolysis was abandoned because it proved impossible to enter the graft from the right femoral artery. The patient then underwent a surgical thrombectomy performed through a small transverse incision in the middle of the graft. The incision in the graft was sutured with prolene and the wound closed over a suction drain. Unfortunately re-thrombosis occurred almost immediately. The patient was returned to the radiology department and a direct percutaneous puncture of the graft was made close to the anastomosis with the right common femoral artery. Thrombolysis using rt-PA was started according to the protocol described above. Lysis of thrombus within the graft was complete after one bolus of rt-PA. Residual thrombus was identified in the distal vessels. It FIGURE 3 - F d .ngiopm showing completproved impossi ble to place - t h e cd -WsiSlongstanding supficia1 catheter securely into each affected fnwnl artery occlusion is Jeen and poor runvessel in order to administer further off occm via prorunda fnnOri.9. 100
direct bolus doses. The catheter was therefore positioned just beyond the distal end of the graft and rt-PA infused. Interim angiograms showed progressive lysis of the residual thrombus and complete lysis was achieved after 2 hours. The final angiogram showed a stenosis at the distal anastomosis to the left femoral artery. Immediate balloon angioplasty was performed with rapid subjective and objective improvement in the condition of the patient’s left leg. A small haematoma developed around the operative and puncture sites despite local pressure and the total blood loss into the drain was 675m1. The clinical improvement in the left foot was maintained and the patient was discharged three days after the procedure able to walk 50yds. An IV-DSA three weeks after discharge showed the graft to be patent. Case 2 An 83 year old female presented with a three day history of acute left leg claudication at 5 yards. The patient stated that these were her exact symptoms prior to her operation two years previously when a right to left femorofemoral bypass graft was inserted. On examination the left foot was severely ischaemic but viable. The right femoral pulse was palpable but graft pulsation and the left femoral pulse were absent. A direct percutaneous puncture of the graft was made close to the anastomosis to the right femoral artery. An angiogram showed extensive thrombus within the graft (Figure 1). Thrombolysis using rt-PA was performed according to the protocol and interim angiograrns showed progressive thrombolysis (Figure 2). After the third bolus the thrombus was completely lysed (Figure 3). N o focal stenosis or other causative lesion was identified. Following the procedure the patient’s symptoms and signs improved rapidly. The patient remained well at follow-up six weeks after the procedure.
DISCUSSION The acutely thrombosed femorofemoral bypass graft is an uncommon but difficult clinical problem. Many patients with such grafts have advanced arterial disease and have had extensive previous surgery which makes the surgical management difficult. The method of graft access and thrombolysis we describe is novel and based on modifications of established techniques (4,s). We have been unable Australasian Rodiolog,~.Vol. 36. No. 2 . May. 1992
THROMBOLYSIS AND THE FEMOROFEMORAL BYPASS GRAFT to find any reports of femorofemoral graft thrombolysis in the radiological or surgical literature and direct graft puncture in this situation is not a documented technique. Lack of backflow from the thrombosed graft makes the determination of needle position more difficult than usual. However, most femorofemoral grafts lie subcutaneously and are palpable enabling relatively easy access. Subsequent manipulation allows the catheter to be passed through the graft and into the native vessels of the recipient leg. Once the graft thrombus has been lysed the vascular anatomy of the recipient limb can be demonstrated and assessed for stenoses and other factors predisposing to thrombosis. If a suitable lesion is identified then immediate angioplasty can be performed. T h e lack of reports concerning direct graft puncture of extra-anatomic grafts means that there is no information relating to the complications that might arise. However, puncture of aortofemoral grafts is well documented and carries no greater risk of complications than native vessel puncture (6). Clearly the risk of problems will be greatly increased with the employment of fibrinolytic agents but this should not represent a major problem in superficially situated grafts which are easily compressible and accessible to surgical intervention if required. It would be preferable to access the thrombosed graft from the native vessels on the run-in side of the graft. This was attempted in the first case but it proved technically impossible to manoeuvre the catheter through the anastomosis into the graft. A direct puncture was performed only after a failed surgical thrombectomy. In the second case, the initial approach was to puncture the graft percutaneously. It would appear from the results of these two cases that persistent thrombus in the short segment of graft proximal to the puncture site is not a problem. Presumably, either there is sufficient rt-PA reflux proximally to effectively lyse the clot, or, less likely, the small plug of residual thrombus is carried ‘downstream’ by the inflow of blood into the clearing distal graft. It would seem prudent however to puncture the graft as close to the donor artery anastomosis as possible.
The usual anatomical configuration of cross-over grafts makes catheterisation of the origin particularly difficult if not impossible. The same difficulties occasionally arise when attempting to clear occluded femoro-distal grafts. Often there may be no accurate record Australasian Radiology. VoI. 36. No. 2 May. 1592
as to the precise orientation of the graft origin. If no stump is visible on angiography then cannulation may be impossible. In such cases direct puncture of the graft (with limited surgical exposure if required) may be a viable alternative to a major surgical procedure. Our initial experience with this technique is showing promising results. Recombinant tissue type plasminogen activator has been used extensively in peripheral arterial thrombolysis (7-1 1). The advantages of rt-PA are its considerable fibrin specificity, characterized by a high affinity for fibrin bound plasminogen relative to circulating plasminogen. This allows localised conversion of plasminogen to plasmin at the clot interface facilitating effective local thrombolysis and avoiding systemic fibrinolysis (8). Infusion through a catheter or luminal wire embedded in the thrombus is the usual mode of administration of rt-PA. The rate of infusion is usually 0.05- O.lmg/kg/hr and the catheter is repositioned as required. In our hands this technique has resulted in shorter procedure times and more effective thrombolysis of the distal vessels when compared to those achieved using streptokinase. Research has shown that a high dose of rt-PA infused over a short time has less systemic lytic effect, whereas a lower dose infused over a longer period is associated with increased fibrinogenolysis (8). As the duration of infusion increases systemic fibrinolysis increases, resulting in increased systemic lysis. This poses the question whether shorter periods of treatment will decrease systemic lytic activity. Giving rt-PA in a 5mg bolus, up to a maximum of three doses each separated by an interval is an attempt to increase the rate of thrombolysis and to reduce infusion times (5). The 10 minute interval between boluses was selected as the half-life of rt-PA is approximately 5-9 minutes. It has yet to be shown that the bolus technique is better o r safer than conventional infusion techniques and this is the subject of an ongoing joint study between our own department and that of Dr Juhan of Hopital Nord, Marseilles, France. However, many of the complications encountered during thrombolysis are related to the catheter or to systemic thrombolysis and in theory both may be reduced by shortening infusion times.
small haematoma and had a measured loss of 675mls into the surgical drain. The size of this loss is attributable to the incision for surgical thrombectomy performed immediately before the thrombolysis. Thrombolysis was only performed in such circumstances because of a severe deterioration in the circulatory state of the limb and in the knowledge that bleeding could be monitered accurately and flow through the graft arrested if necessary. Losses in the second case were negligible. Patients with acutely thrombosed femorofemoral bypass graft present a complex management problem. Previous vascular surgery may make further surgery difficult and the overall condition of the patients is often poor. In such circumstances bolus administration of rt-PA directly into the graft may be a relatively rapid, effective and safe method of restoring blood flow to the affected limb. REFERENCES 1. Vetto RM. The treatment of unilateral iliac artery obstruction with a transabdominal subcutaneous femorofemoral graft. Surgery 1962; 52: 342-345. 2. Mannick JA, Maini BS. Femorofemoral grafting: indications and late results. Am J Surg 1978; 1 3 6 190-192. 3. Fahal AH. McDonald AM, Marston A. Femorofemoral bypass in unilateral iliac artery occlusion. Br J Surg 1989; 76: 22-25. 4. Sullivan KL, Gardiner GA, Shapiro MJ, Bonn J, Levin DC. Acceleration of thrornbolysis with a high-dose transthrombus bolus technique. Radiology 1989: 173: 805-808. 5 . Juhan C. Haupert S. Miltgen G. Barthelemy P. Intra-arterial infusion of r-TPA. A two stage procedure. J Cardiovasc Surg 1990. 31: 89. 6. Eisenberg RL, Mani RL, McDonald EJ. The complication rate of catheter angiography by direct puncture through aortofemoral bypass grafts. Radiology 1976; 126: 814-816. 7. Graor RA. Risius B. Young JR ef al. Peripheral artery and bypass graft thrombolysis with recombinant human tissue type plasminogen activator. J Vasc Surg 1986; 3: 1 15- 124. 8. Graor RA, Risius B, Lucas FV er al. Thrombolysis with recombinant human tissue-type plasminogen activator in patients with peripheral mery and bypass graft occlusions. Circulation 1986; 74 (suppl I): 15-20, 9. Hess H, Mietaschk A, Bruckl R. Peripheral artery occlusions: a six year experience with local low dose thrombolytic therapy. Radiology 1987: 163: 753-758. 10. Earnshaw JJ, Westby JC, Gregson RHS. Makin GS. Hopkinson BR. Local thrombolytic therapy of acute peripheral arterial ischaemia with tissue plasminogen activator: a dose-ranging study. Br J Surg 1988 75: 1196-1200. 11. Berridge DC. Gregson RHS, Makin GS. Hopkinson BR. Tissue plasminogen activator in peripheral arterial tluombolysis. Br J S U 1990: ~ 77: 179-182.
The commonest complication of thrombolysis is haematoma formation at the puncture site. Case 1 developed a 101
