Reversal of impaired wound repair in iNOS-deficient mice by topical adenoviral-mediated iNOS gene transfer.

Most evidence indicates that nitric oxide plays a role in normal wound repair; however, involvement of inducible nitric oxide synthase (iNOS) has not been established. Experiments were carried out to determine the requirement for iNOS in closing excisional wounds. Wound closure was delayed by 31% in iNOS knockout mice compared with wild-type animals. An identical delay in wound closure was observed in wild-type mice given a continuous infusion of the partially selective iNOS inhibitor N6-(iminoethyl)-L-lysine. Delayed wound healing in iNOS-deficient mice was completely reversed by a single application of an adenoviral vector containing human iNOS cDNA (AdiNOS) at the time of wounding. Reverse transcription PCR identified iNOS mRNA expression in wild-type mice peaking 4-6 d after wounding, and confirmed expression of human iNOS in the adenoviral vector containing human iNOS cDNA-treated animals. These results establish the key role of iNOS in wound closure, and suggest a gene therapy strategy to improve wound healing in iNOS-deficient states such as diabetes, and during steroid treatment.

Promotion and acceleration of diabetic ulcer healing by arginine-glycine-aspartic acid (RGD) peptide matrix. RGD Study Group.

OBJECTIVE: To determine the effectiveness and safety of arginine-glycine-aspartic acid (RGD) peptide matrix in the treatment of diabetic foot ulcers. RESEARCH DESIGN AND METHODS: This randomized placebo-controlled investigator- and patient-blinded prospective multicenter investigation was conducted at three institutional and three private U.S. clinics providing ambulatory care. Sixty-five diabetic patients with chronic full-thickness neurotrophic foot ulcers were enrolled. Six discontinued the study because of adverse events. RGD peptide matrix (Argidene Gel; formerly Telio-Derm Gel) was applied topically twice weekly for up to 10 weeks in patients who otherwise received standard care. Control group patients received topical saline as a placebo plus standard care. The primary method of assessment was the incidence and rate of ulcer closure. All patients enrolled were included in the data analysis. RESULTS: The percentage of patients whose ulcers healed completely in the RGD peptide matrix group (35%; 14 of 40 patients) was over fourfold greater (P = 0.02) than that in the placebo group (8%; 2 of 25 patients). By the study end point (either day of healing or week 10), 30 of 40 (75%) RGD peptide matrix patients had achieved > 50% ulcer closure compared with 12 of 25 (48%) placebo patients (P = 0.03). RGD peptide matrix also significantly (P = 0.03) increased the rate of ulcer closure over the 10 weeks of the study. CONCLUSIONS: RGD peptide matrix treatment promoted and accelerated the healing of chronic diabetic foot ulcers to a significant degree.

Randomized prospective double-blind trial in healing chronic diabetic foot ulcers. CT-102 activated platelet supernatant, topical versus placebo.

OBJECTIVE: To assess the efficacy of topically applied CT-102 APST for treating diabetic neurotrophic foot ulcers. RESEARCH DESIGN AND METHODS: Thirteen patients entered a randomized, double-blind trial of topically applied CT-102 APST vs. placebo (normal saline) gauze dressings for the treatment of nonhealing diabetic neurotrophic foot ulcers. CT-102 APST (Curative Technologies, Setauket, NY) was prepared from homologous platelets and contained multiple growth factors including PDGF, PDAF, EGF, PF-4, TGF-beta, aFGF, and bFGF. Inclusion criteria for subjects included diabetes, ulcer of > 8 wk duration, peri-wound transcutaneous oxygen tension > 30 mmHg, platelet count > 100,000/mm3, and no wound infection. Wounds were excised before entry and were > 700 mm3 but < 50,000 mm3 in volume, < 100 cm2 in area, and involved subcutaneous tissue. RESULTS: In the CT-102 group, 5 of 7 ulcers were healed (100% epithelialized) by 15 wk, but only 1 of 6 ulcers was healed by 20 wk with placebo (P < 0.05). Average percent reduction in ulcer area at 20 wk was 94% for CT-102 vs. 73% for placebo. Daily reduction in ulcer volume was 73.8 +/- 42.4 mm3/day (mean +/- SE) for CT-102 vs. 21.8 +/- 8.1 mm3/day for placebo (P < 0.05). Daily reduction in ulcer area was 6.2 +/- 1.8 mm2/day for CT-102 vs. 1.8 +/- 0.4 mm2/day for placebo (P < 0.05). CONCLUSIONS: CT-102 significantly accelerated wound closure in diabetic leg ulcers when administered as part of a comprehensive program for the healing of chronic ulcers.

Iatrogenic myocardial edema with potassium cardioplegia.

Postischemic myocardial edema depresses left ventricular function and coronary perfusion. Pharmacologic cardioplegia is being used increasingly to enhance myocardial protection during cardiac operations. In the present study we varied the colloid osmotic and osmotic pressures and the infusion pressures of four cardioplegic solutions to determine their respective roles in producing or preventing myocardial edema in a nonischemic setting. We found that myocardial edema during potassium cardioplegia (1) is independent of infusion pressures, (2) is caused by isosmotic crystalloid solutions, (3) is worsened by hyposmolar crystalloid solutions, (4) is avoided by the addition of colloid, and (5) is avoided if the solution is made hyperosmotic with the addition of mannitol.

Reducing postischemic damage by temporary modification of reperfusate calcium, potassium, pH, and osmolarity.

This study was designed to determine if ischemic damage could be reduced by modifying blood composition upon reperfusion. After control data had been obtained in seven dogs on prolonged cardiopulmonary bypass, 71 dogs underwent 1 hour of ischemic arrest with topical hypothermia (left ventricular temperature 16 degrees C). We measured left ventricular performance (isovolumetric function curves), compliance (intraventricular balloon), blood flow (microspheres), metabolism (oxygen consumption), and water content (wet/dry weights) before and 30 minutes after ischemia. The initial reperfusate was 500 cc of oxygenated blood given over a period of 5 minutes. Without temporary reperfusate modification, postischemic left ventricular performance was depressed 40% +/- 3%, compliance fell 50% +/- 12%, water content rose 2.5% +/- 0.1%, and left ventricular blood flow and oxygen uptake increased only minimally when cardiac work was increased (function curve). These deleterious changes were reduced significantly, but not prevented, by the following isolated reperfusate modifications: (1) lowering amount of ionic calcium available for cell entry, (2) raising pH to 7.8 to counteract acidosis, (3) raising potassium level to maintain arrest and reduce metabolic demands, and (4) increasing osmolarity (mannitol, 360 mOsm) to counteract edema. In contrast, by combining these modifications to achieve a hypocalcemic, hyperkalemic, alkalotic, and hyperosmolar blood perfusate, it was possible to attain 104% +/- 1% recovery of myocardial performance, 80% +/- 1% restoration of compliance, 60% less postischemic edema, and near-normal augmentation of left ventricular flow and oxygen uptake to meet increasing needs.

Organization and development of a university multidisciplinary wound care clinic.

BACKGROUND: A multidisciplinary wound care clinic was established to diagnose and treat patients with nonhealing ulcers of the lower extremity. METHODS: The clinic was organized under the direction of the departments of vascular surgery and dermatology with support by the departments of plastic surgery, hyperbaric medicine, orthopedic surgery, and podiatry, and a research nurse. RESULTS: In the first 4 years and 3 months, 683 patients were evaluated. One hundred seventy-one patients underwent outpatient testing in the noninvasive vascular laboratory and 30 patients underwent angiography. Causes of the ulcers were venous stasis, 280 patients (41%); diabetic neuropathy, 182 patients (27%); arterial insufficiency, 119 patients (17%); rheumatologic disorders, 38 patients (6%); trauma, 15 patients (2%); and in 49 patients (7%) a variety of other disorders. One hundred seventy-nine operations were performed including 86 operating room debridements, 48 amputations (43 toe, 4 below knee, 1 above knee), 23 arterial bypasses, 1 venous bypass, 14 skin grafts, 2 pedicle flaps, and 5 excisions of tumor. Fifty-six patients with cellulitis were admitted to the hospital for intravenous antibiotics and 12 patients were treated with hyperbaric oxygen therapy. One-hundred thirty-two patients were entered into randomized prospective trials of topical growth factors on Institutional Review Board approved protocols. CONCLUSIONS: We concluded that a multidisciplinary approach to wound care is beneficial to patients with chronic wounds and provides a mechanism for clinical investigation on the healing of problem wounds.

Transcutaneous oxygen measurements in lower extremity ischemia: effects of position, oxygen inhalation, and arterial reconstruction.

Transcutaneous oxygen tension (TcPO2) measurement has been successfully applied to the diagnosis and monitoring of patients with peripheral arterial insufficiency. This study was performed to assess the effects of changes in limb position, oxygen inhalation, and arterial reconstruction on TcPO2 values in patients with peripheral vascular disease. In addition, a TcPO2 index (foot TcPO2/chest TcPO2) was compared with the Doppler-derived ankle-to-brachial index (ABI) to determine which was the more effective monitor of the response to revascularization. Foot TcPO2 values of 22 patients with claudication or rest pain were measured before and after vascular reconstruction. TcPO2 increased after revascularization in both groups regardless of limb position or oxygen (O2) administration. The dependent position and O2 inhalation had an additive effect on TcPO2. Preoperative TcPO2 values in patients with rest pain showed the greatest response to the dependent position, increasing from 14 mm Hg to 33 mm Hg at room air and from 21 mm Hg to 53 mm Hg with O2 inhalation. TcPO2 in both patient groups was remarkably enhanced by O2 administration after revascularization. Postoperative supine TcPO2 values measured at room air increased from 50 mm Hg to 124 mm Hg (148%) in patients with claudication and from 40 mm Hg to 109 mm Hg (173%) in patients with rest pain after O2 inhalation. Comparison of the TcPO2 index with the ABI showed that absolute and normalized TcPO2 values are equally effective in monitoring peripheral arterial insufficiency. This study suggests that placing the limb in the dependent position and administering O2 may augment TcPO2 to levels where symptoms may resolve. The response of TcPO2 to O2 inhalation may be an indicator that reflects the response to revascularization.

Causes of stroke in carotid endarterectomy.

Carotid endarterectomy performed with the patient conscious under regional anesthesia provides a unique opportunity to determine the time of onset of a neurologic deficit and in deduce a likely cause. If a trial period of carotid occlusion is tolerated without the development of a neurologic deficit (96% of our patients), operation may continue without indwelling shunt. Of the 345 patients who had elective carotid endarterectomies performed without shunt, neurologic deficits lasting longer than 24 hours developed in 6 patients (1.7%), and deficits resolving within 24 hours occurred in 15 patients (4.3%). The neurologic deficit developed during carotid dissection in 3 patients, during carotid occlusion in 1 patient, upon release of carotid occlusion in 2 patients, and in the first 5 postoperative days in 15 patients. Of the 15 postoperative deficits, 9 were transient ischemic attacks similar to preoperative episodes, 4 were strokes, and 2 were visual changes. Twenty of 21 deficits were thromboembolic, reperfusion phenomena or were related to hypotension. Only one (0.3% of 345 cases) could be attributed to cerebral anoxia. We believe comparison of raw stroke rates is not valid in comparing methods of cerebral protection, since most perioperative neurologic deficits are not attributable to hypoperfusion. Furthermore, trial carotid occlusion in the conscious patient is a satisfactory method for determining the need to use a shunt.

Upper gastrointestinal endoscopy after cardiac transplantation.

Three hundred four patients have undergone cardiac transplantation at the University of Pittsburgh since 1980. Twenty patients have required 27 upper gastrointestinal (GI) endoscopic procedures. After heart transplantation the primary indications for endoscopy were epigastric pain (six patients with gastritis, one with multiple shallow gastric ulcers, and one with normal test results), mild upper GI bleeding (four patients with esophagitis, two with gastritis, and two with multiple shallow gastric ulcers), dysphagia and odynophagia (two patients with esophagitis), persistent nausea and vomiting (one with normal test results), lower GI bleeding (one with normal test results), and routine follow-up (one with normal test results). After heart-lung transplantation the primary indications for the endoscopy were massive upper GI bleeding (three patients with actively bleeding duodenal ulcers), dysphagia and odynophagia (one patient with esophagitis), mild upper GI bleeding (one patient with gastritis), and routine follow-up (one patient with normal test results). No complications resulted from endoscopy. The procedures were performed in the GI suite without cardiac monitoring. Prophylactic antibiotics were not routinely administered. No patient had a fungal infection of the upper GI tract--a finding attributed to the prophylactic use of nystatin in all patients. Opportunistic viral infections were identified histologically in six patients, including two patients with actively bleeding duodenal ulcers. The possibility of opportunistic viral infections in this immunosuppressed group required aggressive diagnostic techniques, including endoscopy and biopsy, which can be safely performed after cardiac transplantation.

General surgical complications in heart and heart-lung transplantation.

One hundred forty-three patients underwent cardiac transplantation from 1980 to 1985; 122 received a heart, 19 received a heart-lung, and two received a heart-liver transplant. All patients received immunosuppression with prednisone and cyclosporine. General surgical complications have developed since transplantation in 40 patients (28%). Of these, 17 patients have required surgery: exploratory laparotomy (10 patients), inguinal or ventral herniorrhaphy (two patients), repair of false aneurysm of the femoral artery (two patients), repair of lymphocele of the groin (two patients), and incision and drainage of a perirectal abscess (one patient). Of the 10 patients who required laparotomy, three underwent sigmoid resection for a perforated sigmoid diverticulum (all survived), two underwent small bowel resection for perforation (both died), two had free intraperitoneal air with no site of perforation found (one died), one underwent a cholecystostomy and one a cholecystectomy for acute calculous cholecystitis (one died), and one underwent an elective pyloroplasty for gastric outlet obstruction secondary to vagus nerve injury during heart-lung transplantation and survived. All patients who underwent elective surgery survived. Six patients died without operation and at autopsy were found to have unrecognized general surgical complications including pancreatitis (three patients), cecal ulceration with sepsis (two patients), and jejunal perforation secondary to peritoneal dialysis (one patient). Eleven other patients had severe abdominal pain and five had gastrointestinal hemorrhage not requiring operation. Proper management of these patients includes early and aggressive diagnosis of conditions requiring operative intervention, strict attention to surgical technique, and careful titration of dose of immunosuppressive drugs. The 28% incidence of general surgical complications associated with heart and heart-lung transplantation emphasizes the role of the general surgeon in the management of these complex patients.

General surgery in adult hemophiliacs.

From 1976 to 1984, 23 operations were performed on 22 patients with hemophilia (18 patients with factor VIII and four with factor IX deficiency). Elective procedures included resection of abdominal aortic aneurysm, liver transplantation, vagotomy/pyloroplasty, insertion of Mousseau-Barbin tube, colectomy, cholecystectomy, inguinal herniorrhaphy (four patients), colonoscopy/polypectomy, mediastinoscopy, arteriovenous fistula for dialysis, anal fistulectomy, and miscellaneous skin and soft-tissue procedures (five patients). Emergency operations were appendectomy (two patients), repair of bleeding liver biopsy site, and repair of an incarcerated inguinal hernia. There were two deaths (9%) within 30 days of operation, neither directly caused by the coagulopathy. Four patients had bleeding after surgery, which was treated with additional cryoprecipitate or factor concentrate. There were no nonhemorrhagic complications. Before operation, appropriate replacement therapy with factor VIII concentrate, cryoprecipitate, or fresh-frozen plasma was provided. Coagulation factor levels were measured before operation and monitored daily after operation. Generally, factor levels were raised to at least 1.0 U/ml and maintained at greater than 0.5 U/ml for 7 to 14 days after operation. However, when patients were treated with fresh-frozen plasma, plasma exchange was performed and factor levels of approximately 0.35 U/ml were achieved before surgery. We conclude that operations in patients with hemophilia can be accomplished safely with careful monitoring of coagulation factor levels and appropriate replacement therapy.

The syndrome of spontaneous iliac arteriovenous fistula: a distinct clinical and pathophysiologic entity.

While the development of a spontaneous iliac arteriovenous fistula is an uncommon complication of arteriosclerotic aneurysmal disease, its association with a distinct clinical syndrome allows timely operative intervention for this potentially life-threatening event. A review of cases reported in the literature reveals a triad of symptoms consistently associated with the presence of a spontaneous iliac arteriovenous fistula: high-output cardiac failure of precipitous onset, a pulsatile abdominal mass accompanied by a thrill and bruit, and unilateral lower-extremity ischemia or venous engorgement. Survival may be anticipated if an aggressive diagnostic and operative approach is employed.

The role of calcitonin and parathyroid hormone in the pathogenesis of post-thyroidectomy hypocalcemia.

Permanent hypocalcemia complicating thyroidectomy is a rare complication, whereas transient post-thyroidectomy hypocalcemia occurs frequently. Ten patients were studied in an attempt to elucidate the underlying mechanisms. An early and transient postoperative rise in calcitonin (CT) corresponding to a decline in calcium levels was demonstrated. Though there was no significant depression of parathyroid hormone (PTH) levels, the failure of the parathyroids to respond to hypocalcemic stimuli suggests a degree of at least transient parathyroid insufficiency. Transiently elevated CT levels appear to play a significant role in the commonly observed early, transient post-thyroidectomy hypocalcemia following subtotal and total thyroidectomy.

Arterial complications of total knee replacement.

Arterial complications of total knee replacement are rare but may be more frequently encountered as the number of replacement arthroplasties increases. An arterial injury may occur on either an acute or chronic basis, leading to ischemia of the lower extremity. The mechanism of injury may be analogous to that encountered in the popliteal artery entrapment syndrome, but may also result from disruptive forces applied to calcified atherosclerotic vessels by the pneumatic tourniquet or during intraoperative manipulation. A thorough preoperative vascular evaluation should be routinely performed in patients with evidence of coexisting peripheral arterial disease, and baseline Doppler segmental pressures should be obtained. Early detection of an arterial injury may prevent the serious consequences that might otherwise occur.

Wound healing trajectories as predictors of effectiveness of therapeutic agents.

BACKGROUND: One goal of wound healing research is to discover agents to accelerate healing. Regulatory agencies have suggested stringent criteria to determine efficacy, that of 100% wound closure. Data analysis at a single point such as 100% closure does not provide detailed information about agent effectiveness over the entire span of healing. HYPOTHESIS: Wound healing trajectories can provide such information and can be used to demonstrate utility as alternative end points for wound healing trials. DESIGN: Data from 160 patients in 11 clinical trials of diabetic foot ulcers conducted at 2 centers were evaluated. Wound healing trajectories were constructed for patients whose wounds healed (100% closure) and those whose did not (<100% closure) over a 20-week period. The percentage of patients achieving total healing vs time of treatment was plotted and divided into patients receiving a test agent or placebo. RESULTS: The healing trajectories were almost identical for patients achieving complete healing at the 2 centers, as were the trajectories for patients with less than 100% closure. However, the trajectories of patients achieving total healing were significantly different from those not achieving 100% closure. Fifty-two percent of all patients achieved 100% healing by 20 weeks; 61% of patients receiving an experimental agent had total healing compared with 39% of placebo-treated patients. Linear regression suggested that all patients would achieve total healing by 37 weeks. CONCLUSIONS: Since wound healing trajectories for diabetic foot ulcers treated at 2 centers so closely mimic one another, trajectories might be useful efficacy end points, and used to compare significant points along a continuum rather than a single static end point. Shifting of the wound healing trajectory from an impaired to a more ideal course may be considered when determining efficacy of new wound treatments.

Inflammatory aneurysms of the abdominal aorta.

Inflammatory aneurysms of the abdominal aorta (IAAAs) have distinctive clinical and physical characteristics that separate them from typical atherosclerotic aneurysms. They were identified in 19 (7.2%) of 265 patients undergoing abdominal aortic aneurysm repair. Symptoms were present in 12 (63%) of 19, with one patient presenting with rupture, and multiple symptoms were present in six (32%). Intraoperatively, all aneurysms exhibited dense periaortic inflammation. Adjacent structures most frequently involved were the duodenum in 15 (79%) of 19 patients, the left renal vein in six (32%) of 19, and the ureter in five (26%) of 19. Seventeen (94%) of the 18 patients who underwent elective aneurysm resection survived. The involvement of retroperitoneal structures varied in number and severity, demonstrating that a wide spectrum of inflammation is present in IAAAs, making diagnosis and definition difficult.

Effects of pulsatile assistance and nonpulsatile flow on subendocardial perfusion during cardiopulmonary bypass.

We compared the effects of pulsatile and nonpulsatile perfusion in 12 dogs on extracorporeal circulation. In beating empty and fibrillating hearts at 37 degrees and 28 degrees C, coronary blood flow was measured by flowmeter and microspheres at diastolic pressures ranging between 50 and 130 mm Hg. At fixed systemic flow rates (range, 600 to 2,400 ml/min), pulsatile perfusion produced a transient (3 to 4 second) augmentation of diastolic pressure and then resulted in the following: (1) decreased peripheral vascular resistance (p less than 0.05); (2) unchanged peak diastolic pressure (compared with nonpulsatile perfusion); (3) decreased mean aortic pressure (6 to 37%) (p less than 0.05); (4) decreased coronary blood flow (10 to 45%) (p less than 0.05); and (5) decreased subendocardial blood flow (from 512 to 438 ml/100 gm/min) (p less than 0.05). Pulsatile perfusion in beating hearts (37 degrees or 28 degrees C) did not reduce subendocardial vascular resistance, but did improve subendocardial perfusion by 27% and 36% in fibrillating hearts at 37 degrees and 28 degrees C, respectively. We conclude that with the exception of ventricular fibrillation, pulsatile assistance offers no advantage over nonpulsatile perfusion and has the potential disadvantage of requiring higher pump flow rates to achieve any desired level of coronary and subendocardial flow.

Simultaneous radical nephrectomy and repair of abdominal aortic aneurysm.

OBJECTIVES: The combination of abdominal aortic aneurysm repair with other intra-abdominal surgery is controversial. Most studies have shown that a variety of procedures can be performed at the same time as an aneurysm repair with little change in mortality or complication rates. We conducted a retrospective study to determine if aneurysm repair could be safely and effectively combined with radical nephrectomy. METHODS: We studied 10 patients who underwent combined abdominal aortic aneurysm repair and radical nephrectomy during a 4-year period. Results from this group were compared to a separate control group of 10 patients who underwent radical nephrectomy alone and another of 12 patients underwent abdominal aortic aneurysm repair alone, during the same time period. RESULTS: The overall mortality was 10% and significant complications occurred in an additional 10% of patients. Minor, self-limiting complications occurred in 30% of patients. There were no aortic graft infections that occurred in the entire series of patients at 18 months of mean follow-up. There were no remarkable differences in the entire series of patients and the combined values in a separate group of control patients who had undergone either procedure alone. CONCLUSIONS: Simultaneous radical nephrectomy for presumed renal cell carcinoma can be safely combined with repair of abdominal aortic aneurysm in selected patients.

Effect of extensive debridement and treatment on the healing of diabetic foot ulcers. Diabetic Ulcer Study Group.

BACKGROUND: There has been a broad interest in the use of growth factors to treat patients with chronic nonischemic diabetic ulcers. STUDY DESIGN: One hundred eighteen patients were studied in a randomized, prospective, double-blind, multicenter trial comparing treatment with topically applied recombinant human platelet-derived growth factor (rhPDGF) or placebo (vehicle) and were treated until completely healed or to 20 weeks. All patients had aggressive sharp debridement of their ulcers before randomization and repeat debridement of callus and necrotic tissue as needed. The influence of debridement was evaluated by reviewing the records of the office visits where debridement was performed. RESULTS: Forty-eight percent of patients treated with rhPDGF healed compared with 25 percent of patients who received placebo (p = 0.01). The mean percentage of office visits where debridement was performed was comparable for the two treatment groups: 46.8 percent (rhPDGF) and 48.0 percent (placebo). In general, a lower rate of healing was observed in those centers that performed less frequent debridement. The improved response rate observed with more frequent debridement was independent of the treatment group. However, for any given center, the percentage of patients who healed was greater with rhPDGF than placebo. CONCLUSIONS: Wound debridement is a vital adjunct in the care of patients with chronic diabetic foot ulcers.

Foundations of good ulcer care.

Diabetic foot ulcers are a significant healthcare problem affecting more than 1 million patients at some point in their lifetime. Good ulcer care begins with thorough assessment of the ulcer, which includes determining whether the ulcer is infected and whether neuropathy or peripheral vascular disease is present. The principles of good wound care include use of proper footwear, non-weight-bearing limb support, use of appropriate antibiotics, debridement, aggressive revascularization, control of serum glucose levels, and careful monitoring of the ulcer. For refractory ulcers, new therapies, such as the use of exogenous recombinant growth factors, are being developed that may have a significant benefit in treating these ulcers and lowering the amputation rate.