Gary R. Seabrook

Monitoring functional patency of in situ saphenous vein bypasses: The impact of a surveillance protocol and elective revision

Implementation of a protocol that monitored in situ saphenous vein bypass hemodynamics for low-flow states provided insight into the pathophysiologic characteristics and time course of graft failure. From 1981 to 1988, 250 in situ bypasses to popliteal (n = 83) or tibial (n = 167) arteries were performed in 231 patients. Indications for operation included critical limb ischemia in 232 cases (93%), popliteal aneurysm in 11 cases (4%), and disabling claudication in seven cases (3%). Arterial pressure measurements, continuous-wave Doppler spectral analysis, and duplex ultrasonography were used to assess patency, detect hemodynamic changes indicative of graft stenosis, and localize anatomic hemodynamic changes indicative of graft stenosis. Seventy grafts with correctable anatomic lesions (retained venous valves, graft stenosis, arteriovenous fistula, native vessel atherosclerosis) that decreased graft blood flow or ankle arterial pressure or both were identified. Correction of vein conduit or anastomotic lesions comprised 73 (77%) of the 95 revisions performed. Vein-patch angioplasty of a stenosis was the most common secondary operation performed. Graft revision was highest in the perioperative period (10% at 30 days), decreased to 7% per 6-month interval until 18 months, and was 3% per year thereafter. The primary patency rate of grafts not identified to have a correctable lesion was 86% at 4 years, a level similar to the secondary patency of 81% for grafts requiring one or multiple revisions. The surveillance protocol identified grafts with correctable lesions before thrombosis thereby permitting elective revision of patent grafts. Hemodynamic studies confirmed that a frequent mechanism of late failure of grafts was the development of a low-flow state produced by lesions not amenable to revision.

Experience with in situ saphenous vein bypasses during 1981 to 1989: Determinant factors of long-term patency

From 1981 to 1989, 361 consecutive in situ saphenous vein bypasses were performed. Indications for revascularization were critical limb ischemia (n = 335, 93%), popliteal aneurysm (n = 15, 4%), and claudication (n = 11, 3%). Outflow tract was the popliteal artery in 116 (32%) and tibial artery in 245 (68%) of bypasses. At 6 years primary patency was 63% and secondary patency was 81%. During the performance of the in situ bypass procedure, 86 (24%) venous conduits were modified because of a technical failure (n = 49, 13%) or an inadequate vein segment (n = 37, 10%). Secondary patency at 4 years for bypasses requiring modification was 72% compared to 84% for bypasses not modified (p less than 0.05). Atherosclerotic disease of the inflow artery necessitating endarterectomy, patch angioplasty, or replacement lowered primary patency at 3 years (69%) compared to the inflow artery not requiring reconstruction (46%, p less than 0.02). In the follow-up period, 95 (26%) bypasses were revised because of thrombosis or hemodynamic failure. Bypasses requiring revision had a 4-year secondary patency of 68% compared to 88% for bypasses not revised (p less than 0.02). The first 179 cases (1981 to 1985) were compared to the subsequent 182 cases (1986 to 1989). The secondary patency at 3 years for the latter half (92%) compared to the first half (80%) of the experience was significantly improved (p less than 0.02). The secondary patency for bypasses not requiring revision was significantly improved (p less than 0.02) for the latter half (n = 142, 97%) compared to the first half (n = 124, 83%) of the series. Long-term patency with the in situ saphenous vein bypass is dependent on surgical experience, quality of the venous conduit, and atherosclerotic disease of the inflow artery that necessitates reconstruction. Meticulous surgical technique and compulsive bypass surveillance results in superior long-term patency.

Healing of venous ulcers in an ambulatory care program: The roles of chronic venous insufficiency and patient compliance

PURPOSE A nurse-managed/physician-supervised treatment program for venous ulceration was evaluated to determine the influence of venous hemodynamics, comorbidities, patient behavior, and ulcer characteristics on time to healing and time to recurrence. METHODS The clinical course and long-term follow-up of 71 patients with 99 venous ulcers diagnosed between November 1981 and August 1994 were analyzed by a retrospective review of clinic records. Demographic data, severity of venous insufficiency, ulcer characteristics, and patient compliance were studied. Outcome variables were time to complete ulcer healing and time to first recurrence. RESULTS Ninety-one percent of the ulcers healed completely at a median 3.4 months. There were 52 (57%) recurrences at a median 10.4 months. Ulcers on limbs with a venous refill time of 10 seconds or less demonstrated a significantly longer time to complete healing (p < or = 0.03); however, no effect on time to recurrence was observed. Patients who were in strict compliance with the treatment regimen (n = 32) had significantly faster healing (p < or = 0.02) and fewer recurrences (p < or = 0.004) compared with patients who were less compliant (n = 67). CONCLUSIONS Most venous ulcers can be expected to heal when patients are enrolled in a nurse-managed/physician-supervised ambulatory ulcer clinic. Photoplethysmography-derived venous refill time of 10 seconds or less predicted delayed healing. Strict compliance with the treatment protocol significantly decreased the time to healing and prolonged the time to recurrence.

In situ replacement of vascular prostheses infected by bacterial biofilms

Late prosthetic graft infections are commonly the result of coagulase-negative staphylococci that survive within a biofilm on prosthetic surfaces and provoke perigraft inflammation. The indolent nature and microbiologic characteristics of bacterial biofilm infections coupled with the morbidity of graft excision and extraanatomic bypass grafting prompted us to use in situ graft replacement in 15 patients admitted to the hospital with 17 infected graft segments at a mean (+/- SEM) time interval of 70 +/- 16 months after graft implantation (n = 6) or revision (n = 9). Since 1986, 17 grafts (14 aortofemoral, 2 axillofemoral, and 1 femoropopliteal) infected by bacterial biofilms have been treated. Signs on admission included femoral pseudoaneurysm (n = 7), perigraft abscess (n = 6), or graft-cutaneous sinus tract (n = 4). No patient exhibited septicemia. At operation graft incorporation was absent and Grams stain of perigraft exudate showed polymorphonuclear leukocytes but no bacteria. Culture of explanted graft material isolated coagulase-negative staphylococci (n = 12), Staphylococcus aureus (n = 1), and no growth (n = 2). All patients were successfully treated by a regimen that included parenteral antibiotics, removal of involved graft material, excision of inflamed perigraft tissue, and in situ replacement with an expanded polytetrafluoroethylene prosthesis. No deaths, graft thromboses, or deep wound infections occurred after operation. Recurrent graft infection did not develop during a follow-up interval that ranged from 5 to 50 months (mean, 21 months). Diagnosis of vascular prosthesis infection caused by bacterial biofilms can be based on signs at admission and operative findings. Complications of this perigraft infection can be eradicated by antibiotic administration, local debridement, and in situ graft replacement.

Durability of vein graft revision: The outcome of secondary procedures

Occlusive lesions that reduced graft blood flow and ankle systolic pressure were identified in 83 femorodistal saphenous vein bypasses by use of duplex scanning or arteriography. Sites of stenosis included vein conduit (n = 41), anastomoses (n = 20), outflow arteries (n = 15), or inflow (n = 9) arteries. One hundred three secondary procedures consisting of vein-patch angioplasty (n = 31), sequential (n = 21) or interposition (n = 17) graft placement, percutaneous transluminal balloon angioplasty (n = 17), or excision of the lesion and primary anastomosis (n = 16) were performed to correct primary (n = 85) or recurrent (n = 18) graft stenoses. Cumulative graft patency after reintervention was 96% at 1 year, and 85% at 5 years. Stenosis or occlusion of revision sites was less after excision (0 of 16) or replacement (1 of 17) of abnormal segments compared to vein-patch angioplasty (8 of 31) or balloon angioplasty (9 of 18). Sequential or jump grafts constructed to improve graft outflow impaired by either myointimal or atherosclerotic occlusive lesions were the least durable secondary procedures. Five of eight graft failures in this series resulted from sequential/jump graft occlusion. All categories of secondary procedures normalized graft and limb hemodynamics, although only one third of patients reported symptoms of limb ischemia before revision. Surveillance of infrainguinal vein bypasses for occlusive lesions is a valid concept to salvage patent but hemodynamically-failing grafts. Secondary procedures that excised the lesion, used autologous tissue reconstruction, and normalized hemodynamics at the revision site and in the vein bypass were associated with a low incidence of restenosis and prolonged graft patency.

Systemic treatment of venous leg ulcers with high doses of pentoxifylline: efficacy in a randomized, placebo-controlled trial

Several small studies have indicated that the systemic administration of pentoxifylline may accelerate healing of venous leg ulcers. The goal of this study was to further evaluate these findings in a larger scale placebo controlled trial and to explore the effect of the dose of pentoxifylline on healing. The study used a prospective, randomized, double‐blind, parallel group placebo controlled design in a multicenter outpatient setting. Patients with one or more venous ulcer were enrolled, with all patients receiving standardized compression bandaging for treatment for their ulcers. Patients were also randomized to receive either pentoxifylline 400 mg, pentoxifylline 800 mg (two 400 mg tablets), or placebo tablets three times a day for up to 24 weeks. The main outcome measure was time to complete healing of all leg ulcers, using life table analysis. The study was completed as planned in 131 patients. Patients receiving 800 mg three times a day of pentoxifylline healed faster than placebo (p = 0.043, Wilcoxon test). The median time to complete healing was 100, 83, and 71 days for placebo, pentoxifylline 400 mg, and pentoxifylline 800 mg three times a day, respectively. Over half of all patients were ulcer free at week 16 (placebo) and at week 12 in both pentoxifylline groups. Whereas the placebo group had only achieved complete healing in half of the cases by week 16, all of the subjects remaining in the group receiving the high dose of pentoxifylline had healed completely. Treatment with pentoxifylline was well tolerated with similar drop‐out rates in all three treatment groups. Complete wound closure occurred at least 4 weeks earlier in the majority of patients treated with pentoxifylline by comparison to placebo. A higher dose of pentoxifylline (800 mg three times a day) was more effective than the lower dose. We conclude that pentoxifylline is effective in accelerating healing of leg ulcers.

An outcome analysis of carotid endarterectomy: The incidence and natural history of recurrent stenosis ☆ ☆☆ ★ ★★

PURPOSE This report identifies the incidence of recurrent carotid stenosis after carotid endarterectomy (CEA) and records the natural history of the disease process to gain further insight into its proper management. METHODS A prospective surveillance protocol with duplex imaging and velocity spectral analysis was used to detect recurrent stenosis ( > 50% diameter reduction) and to document the clinical outcomes of patients who underwent CEA. Between 1984 and 1993, 619 consecutive CEAs were performed in 587 patients. RESULTS Recurrent carotid stenosis developed in 48 CEA sites (7.8%) during a mean follow-up interval of 34 months (range, 2 to 118 months). Normal results on intraoperative assessment correlated with a 5.6% incidence of recurrent stenosis, compared with a 19% incidence when a residual hemodynamic abnormality was present (p < 0.0003). In the first year after surgery, there were no transient ischemic attacks, strokes, or carotid occlusions from recurrent stenosis, compared with a 27% morbidity rate in later follow-up (p < 0.01). Three patients with recurrent stenosis subsequently had occlusion at the CEA site, two of whom had severe ipsilateral strokes. CONCLUSIONS The incidence of recurrent carotid stenosis is low. Patients are at significant risk for neurologic morbidity when a recurrent stenosis occludes. With a 0.3% incidence of late stroke resulting from carotid bifurcation disease, these data confirm that CEA does provide long-term protection from stroke.

Wound complications of the in situ saphenous vein bypass technique.

Wound complications after in situ saphenous vein bypass occur frequently, lengthen hospitalization, and threaten graft viability. From May 1981 to March 1991, 117 consecutive male patients underwent 126 in situ operations: 45 (36%) femoropopliteal, 75 (59%) femorotibial, and 6 (5%) grafts to the dorsal pedal artery for gangrene or ulcer (n = 69), rest pain (n = 54), or claudication (n = 3). Wound complications developed in 55 grafts (44%): erythema developed in 11, but they healed primarily, 19 had skin edge necrosis or localized lymph leaks, 12 had necrosis or infection into the subcutaneous tissue without danger to the graft, and invasive infections that threatened the graft developed in 13. Risk factors for a subsequent wound infection included the development of a lymph leak (p less than or equal to 0.05) and early postoperative graft revision for thrombosis, wound hematoma, retained valve or arteriovenous fistula (p less than or equal to 0.05). The mean time to appearance of a graft-threatening wound infection was 31 days, and 10 of 13 were located in the distal limb. Twelve of the 13 deep infections required operative debridement, and seven required a flap or split thickness skin graft for coverage. Gram-negative as well as gram-positive infections responded equally well. No grafts were lost, and no deaths occurred. Despite the high incidence of wound complications, an aggressive therapy regimen permitted universal graft salvage.

In Vitro Activities of Moxifloxacin against 900 Aerobic and Anaerobic Surgical Isolates from Patients with Intra-Abdominal and Diabetic Foot Infections

ABSTRACT The in vitro activities of moxifloxacin, ciprofloxacin, levofloxacin, gatifloxacin, imipenem, piperacillin-tazobactam, clindamycin, and metronidazole against 900 surgical isolates were determined using NCCLS testing methods. Moxifloxacin exhibited good to excellent antimicrobial activity against most aerobic (90.8%) and anaerobic (97.1%) microorganisms, suggesting that it may be effective for the treatment of polymicrobial surgical infections.

Preoperative Shower Revisited: Can High Topical Antiseptic Levels Be Achieved on the Skin Surface Before Surgical Admission?

BACKGROUND Skin asepsis is a sentinel strategy for reducing risk of surgical site infections. In this study, chlorhexidine gluconate (CHG) skin concentrations were determined after preoperative showering/skin cleansing using 4% CHG soap or 2% CHG-impregnated polyester cloth. STUDY DESIGN Subjects were randomized to one of three shower (4% soap)/skin cleansing (2% cloth) groups (n = 20 per group): (group 1 A/B) evening, (group 2 A/B) morning, or (group 3 A/B) evening and morning. After showering or skin cleansing, volunteers returned to the investigators laboratory where CHG skin surface concentrations were determined at five separate skin sites. CHG concentrations were compared with CHG minimal inhibitory concentration that inhibits 90% (MIC(90)) of staphylococcal skin isolates. RESULTS CHG MIC(90) for 61 skin isolates was 4.8 parts per million (ppm). In group 1A, 4% CHG skin concentrations ranged from 17.2 to 31.6 ppm, and CHG concentrations were 361.5 to 589.5 ppm (p < 0.0001) in group 1B (2%). In group 2A (4%), CHG levels ranged from 51.6 to 119.6 ppm and 848.1 to 1,049.6 ppm in group 2B (2%), respectively (p < 0.0001). CHG levels ranged from 101.4 to 149.4 ppm in the 4% CHG group (group 3A) compared with 1,484.6 to 2,031.3 ppm in 2% CHG cloth (group 3B) group (p < 0.0001). Effective CHG levels were not detected in the 4% CHG group in selected sites in seven (35%) subjects in group 1A, three (15%) in group 2A, and five (25%) in group 3A. CONCLUSIONS Effective CHG levels were achieved on most skin sites after using 4% CHG; gaps in antiseptic coverage were noted at selective sites even after repeated application. Use of the 2% CHG polyester cloth resulted in considerably higher skin concentrations with no gaps in antiseptic coverage. Effective decolonization of the skin before hospital admission can play an important role in reducing risk of surgical site infections.