Joseph L. Mulherin

Antibiotic Prophylaxis in Vascular Surgery

Preoperative and intraoperative antibiotic prophylaxis of infection in peripheral vascular surgery has been widely used although controlled studies have been lacking. A randomized, prospective, double-blind study of cefazolin versus placebo during 565 arterial reconstructive operations was performed at this hospital from February 1976 through August 1977. Among the 462 patients undergoing surgery of the abdominal aorta and lower extremity vasculature, there was a highly significant difference in the infection rates: 6.8% for placebo recipients versus 0.9% for cefazolin recipients (p <.001). Of the 18 infections, four involved vascular grafts and all four graft infections occurred in the placebo group. Over 8% of abdominal wounds of patients receiving placebo became infected versus 1.2% of cefazolin patients (p <.05). Groin wounds were infected infrequently, 1.1% for placebo patients versus none for cefazolin patients. No infections occurred among 103 brachiocephalic procedures. Skin antisepsis was analyzed retrospectively. Infection rates were significantly higher (p <.01) following hexachlorophene-ethanol versus a povidone-iodine skin preparation. Adverse effects of cefazolin were carefully monitored: no rash, phlebitis, or emergence of resistant strains was observed. A brief perioperative course of cefazolin and povidone-iodine skin antisepsis are recommended in vascular reconstructive surgery of the abdominal aorta and lower extremity vasculature.

Primary graft infections

An amputation rate of 8% to 52% and a mortality rate of 13% to 58% make vascular prosthetic graft infections the most dreaded complication facing a vascular surgeon. In 1978 a randomized prospective double-blind study reported a statistically significant decrease in wound infections in patients treated with prophylactic antibiotics whereas the graft infection difference only approached statistical significance. The present study reviews 2614 arterial prosthetic grafts implanted from January 1975 through June 1986. Twenty-four patients were identified as having a prosthetic graft infection, yielding an overall infection rate of 0.92%. Staphylococcus aureus was the most common organism, occurring in one third of the cases. The most common graft material was polytetrafluoroethylene (PTFE) (33%) followed by Dacron (29%), composite PTFE and Dacron (20%), and umbilical vein grafts (9%). Diabetes was a common factor in one third of the patients. Symptoms of infection were present in 15 patients (63%) within 3 months of operation, with 11 patients showing symptoms within 30 days. The longest interval between operation and onset of symptoms was 48 months. Prophylactic antibiotics were administered to 22 of the 24 patients, but in only 7 of the 22 (29.5%) were they given according to our usual practice. All patients required removal of the infected prosthesis, with limb loss in 17% and death in 17%.

Cefoxitin versus erythromycin, neomycin, and cefazolin in colorectal operations. Importance of the duration of the surgical procedure.

Perioperative parenteral cefoxitin was compared with oral erythromycin, neomycin and parenteral cefazolin in a prospective, double-blind, randomized evaluation of 119 patients undergoing colorectal operations. Patients receiving cefoxitin had a higher wound infection rate than patients receiving erythromycin-neomycin-cefazolin (12.5% v 3.2%, respectively, p = .06). A direct correlation existed between the duration of the operation and the infection rate. Cefoxitin prophylaxis was as effective as erythromycin-neomycin-cefazolin in patients undergoing surgical procedures of 4 hours or less (infection rates of 4.8% and 4.0%, respectively). However, for surgical procedures lasting more than 4 hours, 5 of 14 patients (37.5%) receiving cefoxitin developed a wound infection v 0 of 13 patients receiving erythromycin-neomycin-cefazolin (p < .05). It is speculative as to whether frequent two-gram doses of cefoxitin given during the operation would provide prophylaxis equivalent to erythromycin-neomycin-cefazolin.

Renal artery aneurysm: Selective treatment for hypertension and prevention of rupture

Thirty-nine patients with renal artery aneurysm (RAA) were seen over a period of 15 years. Among 20 women and 19 men, 31 were found to have solitary aneurysms, and eight had multiple RAA. Thirty-three patients had diastolic hypertension; nine of them proved to be of renovascular origin. Of the 18 patients who underwent RAA resection, 13 had reconstruction for treatment of hypertension, three had a solitary functional kidney, one had recurrent flank pain, and one had resection for prevention of rupture in a woman of childbearing age. Six of the 18 patients had aneurysmorrhaphy with primary repair or patching, seven had a resection with an aortorenal bypass, and five patients had six ex vivo renal reconstructions with multiple anastomoses. Nephrectomy was performed in two patients with RAA rupture at the time of childbirth and in one patient with hypertension and RAA in a poorly functioning kidney. Reconstructive procedures for documented renovascular hypertension in seven patients resulted in improvement in all cases. Blood pressure improved in only six of 10 patients operated on with hypertension and no lateralization of renovascular studies. Eighteen patients were observed for one to 16 years without surgery, and none experienced rupture. Resection of RAA is indicated to treat patients with renovascular hypertension, patients with hypertension and a solitary functional kidney, and selected patients with severe hypertension and to prevent rupture in women who may become pregnant. Other patients with asymptomatic RAA can be safely observed clinically without serial arteriograms and without fear of rupture.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryopreserved saphenous vein allografts for below-knee lower extremity revascularization.

ObjectiveCryopreserved saphenous vein allografts have been offered as an alternative conduit for bypass in ischemic limbs. The authors examined the efficacy of this conduit for arterial bypass to the distal popliteal and tibial arteries in patients in whom autogenous vein was not available. Summary Background DataPrevious experience with arterial and venous allografts has been unsatisfactory because of aneurysmal degeneration and poor patency. Endothelial loss and host rejection have been suggested as mechanisms of graft failure. Cryopreservation by modern techniques with rate controlled freezing, dimethyl sulfoxide (DMSO), and other cryopreservants, has addressed these issues and rekindled interest in vein allografts. MethodsOver a period of more than 5 years, 115 cryopreserved vein allografts were implanted in 87 limbs to the distal popliteal (14) or tibial (101) arteries. The indication for surgery was rest pain in 56 procedures (49%), gangrene in 36 (31%), claudication in 21 (18%), and replacement of aneurysmal allografts in 2. Follow-up was 1 to 61 months (mean 25 months). ResultsThere was no significant difference in patency related to site of proximal or distal anastomosis, patency of runoff vessels, use of anticoagulation, age, sex, diabetes, hypertension, smoking, indication, source of graft, or use of multiple segments. Revision was required in six grafts for aneurysmal dilatation. Histologic examination of explanted sections of allografts showed no immune response, and immunosuppressive drugs were not used. ConclusionsAlthough limb salvage has been satisfactory, long-term patency rates for cryopreserved vein allografts are poor when compared with autogenous vein. The cost of cryopreserved allografts far exceeds that of prosthetic grafts, for which comparable and superior results have been reported. Use of cryopreserved vein allografts should be reserved for situations in which adequate lengths of autogenous vein do not exist and the risk of infection of prosthetic grafts is high.

The evolving surgical management of recurrent carotid stenosis

The traditional approach to recurrent carotid stenosis has been repeat endarterectomy or patch angioplasty. Concern with the durability of repeat carotid endarterectomy has resulted in our use of carotid resection with autogenous graft interposition. This study was designed to determine the outcome and efficacy of carotid resection compared with repeat carotid endarterectomy in the management of recurrent carotid stenosis. From 1974 to 1991, 162 operations (repeat carotid endarterectomy 105, carotid resection 57) were performed for recurrent carotid stenosis. Indication for operation was hemispheric symptoms in 63% of patients, nonlateralizing symptoms in 25%, asymptomatic stenosis in 7%, and previous stroke in 5%. Ninety-one percent of patients had stenosis greater than 90% on arteriography. The perioperative stroke rate for carotid resection was 3.5%, with a subsequent rate of 0.0064 strokes per year. For repeat carotid endarterectomy, the perioperative stroke rate was 1.9% with a subsequent rate of 0.011 strokes per year. Graft patency after carotid resection was 93% (mean follow-up, 35 months). Four patients treated with carotid resection had graft thrombosis, and two of the four remained asymptomatic. After repeat carotid endarterectomy, one patient had carotid thrombosis, and recurrent stenosis greater than 50% developed in 23 patients (mean follow-up, 64 months). Twenty patients treated with repeat carotid endarterectomy underwent an additional operation for further symptomatic recurrent carotid stenosis. We conclude carotid resection is a safe and effective alternative to repeat carotid endarterectomy for patients undergoing operation for recurrent carotid stenosis.

The role of graft material in femorotibial bypass grafts.

“Newer‘’ graft substitutes are being widely used in arterial reconstructive procedures in the infrafemoral region. A retrospective study of 101 consecutive femorotibial bypass grafts compares autogenous saphenous vein (ASV), polytetrafluoroethylene (PTFE), and glutaraldehyde tanned (GA) human umbilical cord vein, Symptoms prompting arterial reconstruction was rest pain or tissue necrosis in 90%. ASV (57 bypasses) was the material of choice, but when inadequate or unavailable PTFE, (29 bypasses) or GA (15 bypasses) were used. The immediate and one year patency in ASV was 92–82%. A high incidence of failure occurred in both the PTFE and GA grafts so that patency at one year was 24 and 10% respectively. An overwhelming statistical significance occurs with respect to patency in the three groups of grafts (p = 0.0002). This extremely high incidence of failure in these graft materials has prompted us to use cephalic and basilic veins in those patients which we feel require arterial reconstruction for relief of symptoms.

Technical complications of endovascular abdominal aortic aneurysm repair

PURPOSE Results from 34 endovascular repairs of abdominal aortic aneurysms are reviewed to identify technical complications and relate them to anatomic and technical features of the operation. METHODS Twenty-one patients underwent attempted tube graft repair (mean follow-up, 13 months). Thirteen patients underwent placement of a bifurcated graft (mean follow-up, 7.2 months). RESULTS Twenty-five patients (74%) underwent repair without technical complication (16 tube graft and nine bifurcated graft). Of five patients who had tube graft complications, two involved small iliac arteries and resulted in arterial injury. One of these patients needed a femorofemoral bypass procedure, and the other required conversion to standard operation. Two patients had distal leaks associated with the attachment system, and one patient had misplacement of the distal attachment system. The two patients who had leaks were followed-up; one required operation after 7 months, whereas the other leak sealed. The patient who had distal attachment system misplacement had a second endograft placed within the first to provide a distal seal. The four patients who had bifurcated graft complications involved two graft limb stenoses, one managed with a Palmaz stent and the other with balloon angioplasty. The patient treated with balloon angioplasty had graft thrombosis 1 week after the operation, which resulted in the need for a femorofemoral bypass procedure. Another bifurcated graft patient had a graft limb twist, which has resulted in chronic claudication. One patient had placement of a limb too proximal in the common iliac artery with chronic leak, and an open operation was performed 18 months later. CONCLUSIONS Technical complications in this series seem to be associated with short distal necks, small iliac arteries, tortuous iliac arteries, and atherosclerosis at the aortic bifurcation. We believe that experience and understanding of these issues will reduce the risk of these complications in the future.

The surgical reconstruction of the proximal subclavian and vertebral artery

Endarterectomy, bypass, or direct arterial anastomosis are used to restore flow in a compromised vertebral or subclavian artery. During 20 years of experience in surgical relief of stenosis of the proximal vertebral and subclavian arteries, we now prefer an anastomosis between the involved vertebral or subclavian artery. We have performed 411 such procedures. There has been one death (0.2%), with reoperation necessary in three patients (0.0%). No neurologic morbidity has been associated with this procedure.

The lesser saphenous vein: Autogenous tissue for lower extremity revascularization

From December 1980 to December 1985, 54 patients underwent 56 lower extremity arterial procedures with the use of lesser saphenous vein (LSV) as graft material. LSV was used in all cases because a satisfactory greater saphenous vein (GSV) was unavailable to accomplish the proposed revascularization. Indications for operation were rest pain, ulceration, and gangrene (74%), and 26% had claudication alone. Fifty of the 56 procedures were femorotibial and femoroperoneal bypasses. Three graft combinations were used: LSV alone (29), lesser saphenous vein and other autogenous vein composites (LSV/AUTO) (14), and lesser saphenous vein with synthetic composite grafts (LSV/SYN) (13). Graft patency rates were determined by life-table analysis. The 3-year patency rate for LSV was 60% and for LSV/AUTO was 38%. LSV/SYN graft composites had a graft patency rate at 18 months of 21%. These data suggest that the LSV may function as an autogenous venous graft for lower extremity revascularization when sufficient GSV is not available.