Safety of a non-viral plasmid-encoding dual isoforms of hepatocyte growth factor in critical limb ischemia patients: a phase I study

We aimed to evaluate in a phase I dose-escalation study, the safety of intramuscular injections of a novel non-viral plasmid DNA expressing two isoforms of human hepatocyte growth factor (HGF) (VM202) in patients with critical limb ischemia (CLI). In total, 12 patients with CLI and unsuitable for revascularization were consecutively assigned to increasing doses (2 to 16 mg) of VM202 administered into the ischemic calf muscle at days 1 and 15. Patients were evaluated for safety and tolerability, changes in ankle- and toe brachial index (ABI and TBI), and pain severity score using a visual analog scale (VAS) throughout a 12-month follow-up period. Median age was 72 years and 53% of the patients were male. VM202 was safe and well tolerated with no death during the 12-month follow-up. Median ABI and TBI significantly increased from 0.35 to 0.52 (P=0.005) and from 0.15 to 0.24 (P=0.01) at 12 months follow-up. Median VAS decreased from 57.5 to 16.0 mm at 6 months follow-up (P=0.03). In this first human clinical trial, VM202, which expresses two isoforms of human HGF, appear to be safe and well tolerated with encouraging clinical results and thus supports the performance of a phase II randomized controlled trial.

Natural history of composite sequential bypass: ten years' experience

BACKGROUND

We previously reported 48-month patency rates of composite sequential bypass (CSB) approaching 60%. Yet, extended patency and limb salvage rates are unknown.

HYPOTHESIS

Long-term patency and limb salvage rates of CSB are affected by sex, bypass configuration, and warfarin therapy.

DESIGN

Medical records of all patients who underwent CSB during a 10-year period were retrospectively reviewed.

SETTING

A referral center for the Chicago, Ill, region.

PATIENTS

One hundred consecutive patients (mean age, 68.8 years; 57% were men and 49% had diabetes) undergoing 102 CSBs for limb salvage (ulcer, 43%; rest pain, 39%; and gangrene, 18%) from January 1986 to January 1996 were identified.

INTERVENTIONS

Warfarin was used after surgery by 72% of patients and aspirin was used by the remainder of them.

MAIN OUTCOME MEASURES

Life table primary patency and limb salvage rates were compared for sex, diabetes mellitus status, location of distal prosthetic anastomosis (above knee vs. below knee), and anticoagulation drug therapy (warfarin sodium vs aspirin) with log-rank statistics.

RESULTS

Primary patency of CSB was 56% at 24 months, 29% at 48 months, and 20% at 84 months (SE <10%; mean follow-up, 19.6 months [range, 1.0-110.0 months]). Limb salvage rates were 64% at 24 months, 30% at 48 months, and 23% at 84 months (SE <10%); 66% and 90% of patients had failed grafts requiring amputation by 3 months and 1 year, respectively.

CONCLUSIONS

Composite sequential bypass for limb salvage provides reasonable 2-year patency. However, patency rates steadily declined from year 2 to year 5. After CSB failure, limb salvage rates are poor, with 90% of patients progressing to amputation within 1 year.

Thoracoscopically-assisted thoraco-femoral bypass in a canine model

Interest in minimally invasive procedures for vascular disease has grown tremendously over the past few years. Herein, we report our initial experience with a thoracoscopically-assisted thoraco-femoral bypass in a larger animal model. Included are various approaches to a final recommendation for the technique.

Minimally invasive thoracoscopic thoraco-femoral bypass: a case report

Thoracoscopic techniques have improved a variety of thoracic surgical procedures. Thoraco-femoral bypass is an exceptional alternative to standard thoracoscopic thoraco-femoral bypass. Herein we report our initial human experience with a thoracoscopic thoraco-femoral bypass.

Increased plasma levels of metalloproteinase-9 are associated with abdominal aortic aneurysms

PURPOSE

Previous investigators have identified disease-specific elevations of metalloelastase-9 (MMP-9) in aneurysm tissue biopsies. We hypothesized that circulating MMP-9 might also be elevated in patients with aneurysms. The purpose of this study was to compare plasma and aortic tissue MMP-9 levels in patients with infrarenal aneurysms (AAAs), patients with symptomatic aortoiliac occlusive disease (AOD), and healthy patients.

METHODS

A sandwich enzyme-linked immunosorbent assay was used to measure plasma MMP-9 in patients with AAA (n = 22; mean age, 72.7 years), with AOD (n = 9; mean age, 60.5 years), and without disease (n = 8; mean age, 35.3 years). The MMP-9 levels also were measured in 48-hour supernatants of organ culture tissue explants from patients with AAA (n = 10; mean age, 66.2 years) and AOD (n = 5; mean age, 50.4 years) and organ donors (n = 7; mean age, 48.1 years). The results were reported as the mean +/- the standard error of the mean and analyzed with analysis of variance with multivariate regression.

RESULTS

The plasma MMP-9 levels were significantly higher in the patients with AAA (85.66 ng/mL +/- 11.64) than in the patients with AOD (25.75 ng/mL +/- 4.159; P <.001) or the healthy patients (13.16 ng/mL +/- 1. 94; P <.001). No significant difference in plasma MMP-9 levels between patients with AOD and healthy patients was identified. The patients with multiple aneurysms had significantly higher levels of plasma MMP-9 than did the patients with an isolated AAA (134.68 ng/mL +/- 17.5 vs 71.03 ng/mL +/- 10.7; P <.04). In organ culture, AAA and AOD tissue explants produced significantly higher levels of MMP-9 (3218.5 ng/gm +/- 1115.2 and 1283.1 ng/gm +/- 310.6 aortic tissue) than did disease-free explants (6.14 ng/gm +/- 2.3 aortic tissue; P <.0001). No significant difference in MMP-9 production between AAA and AOD explants was identified.

CONCLUSION

Plasma MMP-9 levels are significantly higher in patients with AAA than in patients with AOD or in healthy volunteers. The patients with multiple aneurysms have higher levels than those patients with an isolated AAA. Organ culture studies suggest that diseased aortic tissue is the source of MMP-9.

Transcatheter embolization of a ruptured superior gluteal artery aneurysm: case report and review of the literature

PURPOSE

To report the successful coil embolization of a true gluteal artery aneurysm and review therapeutic options for this rare condition.

METHODS AND RESULTS

A ruptured superior gluteal artery aneurysm in a symptomatic 80-year-old man was successfully thrombosed by embolization using a combination of Gianturco coils and helical platinum microcoils. Six-month computed tomography demonstrated persistent thrombosis of the aneurysm and resolution of the perivascular blood.

CONCLUSIONS

This report offers support for the use of catheter-based techniques as an alternative to standard surgical repair of gluteal artery aneurysms.

Size matters: the relationship between MMP-9 expression and aortic diameter

BACKGROUND

Despite a wealth of data detailing increased metalloproteinase (MMP)-9 expression and activity in abdominal aortic aneurysms (AAAs), no studies examine the relationship between aortic size and MMP-9 expression. Because elastolysis occurs early in AAA formation, we hypothesized that MMP-9 expression would vary with aortic diameter. The purpose of this study was to measure MMP-9 mRNA levels in AAAs of various diameters and define the relationship between AAA size and MMP-9 expression.

METHODS AND RESULTS

MMP-9 mRNA levels were measured by competitive polymerase chain reaction (PCR) using gene-specific external standards with cDNA from AAAs (n= 19) and normal aortas (n=4). Levels were normalized to GAPDH mRNA, determined separately via competitive PCR, to control for efficiency of reverse transcription. AAA size was measured on CT scans obtained within 6 weeks of surgery. MMP-9/GAPDH mRNA transcript levels in AAAs were expressed as mean+/-SEM and analyzed by ANOVA with a Tukey adjustment. There was a fourfold elevation in MMP-9/GAPDH mRNA transcript levels in 5.0- to 6.9-cm AAAs (98.06+/-15.19) compared with small (3.0- to 4.9-cm) AAAs (20.87+/-5.15, P<.03), large (>7-cm) AAAs (27.16+/-14.56, P<.01), or normal aortas (3.57+/-1.13, P<.003). The results did not change when they were normalized to patient height, nor were there significant differences in risk factors, age, or sex in each AAA group.

CONCLUSIONS

MMP-9 mRNA expression is significantly higher in moderate-diameter (5- to 6.9-cm) AAAs than either small (<4.0-cm) or large (>7.0-cm) AAAs. Increased MMP-9 expression may account for the propensity of AAAs >5 cm to continue to expand, in contrast to smaller aneurysms. Lower levels in AAAs >7 cm suggest that increases in other enzymes or in diameter-dependent mechanical stress on the aortic wall are responsible for their characteristic rapid expansion and high rupture rates.

Expression of matrix metalloproteinases and their inhibitors in aneurysms and normal aorta

BACKGROUND

Abdominal aortic aneurysms (AAAs) are characterized by degradation of collagen and elastin resulting from increases in matrix metalloproteinase (MMP) activity. Previous authors have identified isolated increases in expression of specific MMPs in AAAs, but none have compared relative levels of expression of particular MMPs to one another or to those of their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs). This study proposes to quantify relative mRNA levels for interstitial collagenase (MMP-1), 72 kd type IV collagenase (MMP-2), 92 kd type IV collagenase (MMP-9), TIMP-1, and TIMP-2 in normal aorta (NA) and AAA to provide insight as to the relative importance of each in aneurysm formation.

METHODS

Competitive polymerase chain reactions (PCRs) with gene-specific external standards and cDNA derived from AAAs (n = 8; mean age, 67.4 years) and NA (n = 5; mean age, 40.6 years) were used to quantify mRNA levels. Results were normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA levels, determined by means of competitive PCR, and compared by means of Mann-Whitney statistics.

RESULTS

Significant increases in MMP mRNA expression in AAA over NA were observed for MMP-1 (3.64 versus 0.3, p = 0.007), MMP-9 (78.03 versus 3.35, p = 0.003), TIMP-1 (835.32 versus 477.2, p = 0.027), and TIMP-2 (18.09 versus 4.14, p = 0.003). The ratio of MMP to TIMP mRNA levels was higher in AAA than NA (0.135 versus 0.045, p = 0.018).

CONCLUSIONS

Increases in expression of MMP-1, MMP-9, and MMP/TIMP ratios may result in increased proteolysis and matrix degradation, which characterize AAAs. MMP-9 appears to be the predominant metalloproteinase expressed in AAA, because its mRNA levels were more than 20 times and 2 times higher than those of MMP-1 and MMP-2, respectively. TIMP-1 mRNA levels were in molar excess to those of any of the metalloproteinases studied.

Differential patterns of atherosclerotic disease in patients with unilateral hemiparesis resulting from poliomyelitis: case reports demonstrating the possible effect of hemodynamics

The relative importance of hereditary and mechanical factors in the pathogenesis of aneurysms remains as controversial today as it was two decades ago. The cases of two patients with unilateral paresis resulting from poliomyelitis who presented with abdominal aortic aneurysms are reported. In addition, each patient had iliofemoral aneurysms contralateral to, and iliofemoral occlusive disease ipsilateral to, their affected extremity. The two cases detailed within this report suggest that hemodynamic forces may alter the pattern of disease in arteries affected by arteriosclerosis.

Perioperative low molecular weight heparin for infrageniculate bypass

PURPOSE

Recent studies suggest that subcutaneous low molecular weight heparin (LMWH) is a safe, effective alternative to intravenous heparin (IVH) for deep venous thrombosis. LMWH may also be a safe, effective alternative to IVH when necessary for lower extremity bypass procedures performed with polytetrafluoroethylene (PTFE) grafts. The purpose of this study was to compare subcutaneous LMWH with IVH for perioperative anticoagulation in patients who underwent infrageniculate bypass procedures with PTFE grafts.

METHODS

Of 361 lower extremity bypass operations performed at a single center over a 32-month period, 76 were to the tibial or below-knee levels using PTFE grafts for limb salvage. Seven patients were excluded because of absolute indications for perioperative IVH (ventricular thrombus in 1 patient, prosthetic valve in 2, cardiac dysrhythmia in 2, and documented hypercoagulable syndrome in 2), leaving 68 patients (35 women; mean age, 69.8 years) with 69 bypass procedures for study. Grafts completed in the past 16 months were treated with LMWH (28 grafts; Oct. 1994 to Jan. 1996) and were compared with 41 consecutive control grafts from the previous 16-month interval (Apr. 1993 to Oct. 1994) who received IVH. There were similar percentages of composite bypasses (IVH, 50%; LMWH, 46%), patients with tissue loss or gangrene (IVH, 56%; LMWH, 61%), and patients with prior ipsilateral bypass (IVH, 57%; LMWH, 56%) in each group. Age, sex, and atherosclerotic risk factors were also similar between the two groups.

RESULTS

Morbidity rates (IVH, 19%; LMWH, 11%) and mortality rates (IVH, 2.5%; LMWH, 4%) were not significantly different. There were no significant differences in the number of grafts that failed before discharge (IVH, 1; LMWH, 0) or percentage of hemorrhagic complications (IVH, 15%; LMWH, 7%). The mean number of postoperative hospital days (IVH, 9.5; LMWH, 7.2; p < 0.009) and coagulation monitoring studies (IVH, 22; LMWH, 8.4; p < 0.0001) were significantly decreased in patients who were anticoagulated with LMWH. The mean number of days before conversion to oral anticoagulation (IVH, 7.3; LMWH, 8.0) did not differ significantly.

CONCLUSIONS

When perioperative anticoagulation is deemed necessary, LMWH provides a safe, effective alternative to IVH for infrageniculate PTFE bypass grafting procedures. LMWH may reduce the number of postoperative hospital days and coagulation studies by allowing discharge before therapeutic anticoagulation with warfarin.

Peripheral vascular disease in spinal cord injury patients: a difficult diagnosis

The timely detection of peripheral vascular disease (PVD) in spinal cord injury (SCI) patients is difficult because the usual symptoms of claudication and rest pain are absent. In fact, the initial manifestation of PVD in SCI patients is often advanced gangrene, so that healing, primarily or following major amputation, is either difficult and prolonged or impossible. In addition, sacral and ischial pressure sores common among SCI patients may be exacerbated and reconstruction made more difficult by PVD. Five SCI patients presented with lower extremity gangrene as the initial recognized manifestation of PVD at our institution between January 1992 and January 1994. All 5 patients had risk factors for PVD. Four out of ten limbs in these patients required amputation, either above the knee or below the knee. Three patients required concurrent vascular reconstruction of the aortoiliac segments, including an aortobiprofunda femoral bypass, an iliac embolectomy with femoral-femoral bypass, and iliac angioplasty. Three patients had ischial and/or sacral pressure sores that had recurred following multiple musculocutaneous flap reconstructions before vascular disease was recognized. The timely diagnosis of PVD involving the iliac segment in the SCI patient is sometimes overlooked and is often necessary to optimize the treatment of both lower extremity ulcers and sacral/ ischial pressure sores common among these patients.

In situ localization and quantification of seventy-two-kilodalton type IV collagenase in aneurysmal, occlusive, and normal aorta

PURPOSE

Seventy-two-kilodalton type IV collagenase (MMP-2), a potent collagenase and elastase, is present in inflammatory disease states and may be important in the pathogenesis of aortic aneurysms. Alteration in expression of MMP-2 or its inhibitor, the tissue inhibitor of metalloproteinases type two (TIMP-2), could increase extracellular matrix degradation and lead to aneurysm formation. The purpose of this study is (1) to measure relative tissue levels of MMP-2 and TIMP-2 mRNA in aneurysmal, occlusive, and normal human infrarenal aorta; (2) to test for expression by cultured aneurysmal and normal vascular smooth muscle cells (VSMCs); and (3) to identify, in situ, the cells responsible for mRNA production within aneurysmal, occlusive, and normal aortic wall.

METHODS

Total RNA extracted from aneurysmal (n = 8), occlusive (n = 9), and normal (n = 7) tissue was subjected to Northern analysis. Signals for MMP-2 and TIMP-2 were normalized to alpha-tubulin. Mean values +/- SE were compared by use of analysis of variance. Aneurysmal and normal VSMCs were cultured, passaged, and grown to confluence before RNA extraction and Northern analysis. In situ hybridization with digoxigenin RNA probes localized cells responsible for MMP-2 and TIMP-2 mRNA production in histologic sections of aneurysmal (n = 7), occlusive (n = 4), and normal (n = 3) aorta.

RESULTS

Tissue MMP-2 mRNA levels were significantly greater in aneurysmal aorta (1.032 +/- 0.164, n = 5) than in either occlusive (0.553 +/- 0.027, n = 4, p < 0.02) or normal aorta (0.230 +/- 0.038, n = 3, p < 0.002). Differences in TIMP-2 mRNA levels were not significant (aneurysmal aorta 0.207 +/- 0.042, n = 3; occlusive aorta 0.413 +/- 0.164, n = 3; normal aorta 0.260 +/- 0.079, n = 4; p = 0.34), although numbers were small. Cultured aneurysmal and normal VSMCs constitutively expressed both MMP-2 and TIMP-2. In situ studies colocalized tissue MMP-2 and TIMP-2 expression to VSMCs and macrophages surrounding inflammation in aneurysmal adventita, but to atherosclerotic plaque in occlusive aorta.

CONCLUSIONS

MMP-2 and TIMP-2 are expressed in aneurysmal, occlusive, and normal aorta. MMP-2 expression is significantly greater in aneurysmal than in either occlusive or normal aorta. Cultured aneurysmal VSMCs constitutively express both MMP-2 and TIMP-2. Differential patterns of expression seen in situ and elevated tissue MMP-2 mRNA levels in aneurysmal versus occlusive aorta suggest that MMP-2 may be responsible for localized plaque remodeling in occlusive disease and for diffuse adventitial collagen and elastin destruction in aneurysms.

In situ localization and quantification of mRNA for 92-kD type IV collagenase and its inhibitor in aneurysmal, occlusive, and normal aorta

Ninety-two-kilodalton type IV collagenase (MMP-9) is present in aortic aneurysms and may be important to the pathogenesis of this disease. Alteration in expression of MMP-9 or its inhibitor, the tissue inhibitor of metalloproteinase type 1 (TIMP-1), could increase degradation of extracellular matrix and lead to aneurysm formation. The purpose of this study was (1) to measure tissue levels of MMP-9 and TIMP-1 mRNA in aneurysmal (AAA), atherosclerotic occlusive (AOD), and normal (NL) human infrarenal aorta; (2) to test for their expression by cultured AAA and NL vascular smooth muscle cells (VSMCs); and (3) to locate in situ the cells responsible for mRNA production within AAA, AOD, and NL aortic wall. Total RNA extracted from AAA (n = 8), AOD (n = 8), and NL (n = 7) tissue was subjected to Northern analysis. Signals for MMP-9 and TIMP-1 were normalized to alpha-tubulin. Mean values +/- SEM were compared by ANOVA. NL and AAA VSMCs were cultured, passaged, and grown to confluence before RNA extraction and Northern analysis. In situ hybridization with digoxigenin-labeled RNA probes localized cells responsible for MMP-9 and TIMP-1 mRNA expression within sections of AAA (n = 5), AOD (n = 2), and NL (n = 2) aorta. MMP-9 mRNA levels were significantly greater in AAA (0.855 +/- 0.180) than NL (0.046 +/- 0.23) (P < .02), but differences between AOD (0.406 +/- 0.196) and AAA or AOD and NL were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Mesenteric artery bypass: objective patency determination

PURPOSE

Many authors have reported extended relief of intestinal ischemia by use of a variety of reconstructive techniques, but all have relied on symptomatic follow-up. None have objectively measured patency rates. The purpose of this study was to determine the primary patency rates of bypass grafts placed for acute and chronic splanchnic atherosclerotic occlusive disease with use of objective follow-up with mesenteric duplex ultrasound scanning or arteriography.

METHODS

Twenty-five consecutive patients (mean age 61, female/male ratio of 2.7:1) who underwent placement of 38 splanchnic bypass grafts (29 saphenous vein grafts, 9 polytetrafluoroethylene) (22 retrograde, 16 antegrade) for ischemic symptoms (9 acute ischemia: 16 chronic ischemia) between 1984 and 1994 were monitored with either duplex scanning (30 grafts) or arteriography. Life-table and log rank analysis were used to determine and compare graft patency.

RESULTS

Three patients (12%, 2 acute ischemia and 1 chronic ischemia) died after operation. Six patients (30%) had significant morbidity (4 acute ischemia and 2 chronic ischemia). During follow-up from 1 to 136 months (mean 35 months), no patient died of bowel infarction or required revision for recurrent symptoms. Objective testing revealed three graft occlusions. Symptomatic follow-up had a sensitivity of only 33% for graft occlusion when compared with objective measurement. The life-table primary patency rate was 89% at 72 months. Life-table survival for the same patients was 75% at 36 months. Patency rates for antegrade (93% at 36 months) versus retrograde (95% at 36 months) bypass and saphenous vein grafts (95% at 36 months) versus polytetrafluoroethylene (89% at 36 months) were not significantly different (p = 0.47 and 0.43, respectively). Late patency rates of grafts placed for acute ischemia (92% at 36 months) versus chronic ischemia (89% at 36 months) were not significantly different (p = 0.77).

CONCLUSION

Splanchnic bypass for mesenteric ischemia, with a primary patency rate of 89% at 72 months, is an extremely durable form of revascularization. Long-term patency of grafts placed for acute ischemia does not differ significantly from that of bypasses for chronic occlusion. Duplex scanning allows standardized objective periodic follow-up of splanchnic reconstruction. Objective assessment is critical to accurately measure visceral revascularization patency rates.

Descending thoracic aorta-to-femoral artery bypass: ten years' experience with a durable procedure

PURPOSE

Arterial bypass from the descending thoracic aorta to the femoral system provides successful perfusion when an approach to the abdominal aorta is undesirable. This review of a large series with a decade of experience was conducted to better define patency data and the natural history of patients after this operation.

METHODS

During a 10-year period, 21 patients, 18 men and 3 women (mean age 57 years), underwent descending thoracic aorta to left femoral artery bypass with femorofemoral bypass. These were placed to convert axillopopliteal or axillofemoral grafts (12 patients) to a more permanent inflow source. The axillary bypasses had been previously placed to allow removal of infected aortic grafts and had undergone a total of 14 revisions or thrombectomies before conversion. In addition, patients had this procedure after multiple failed attempts (at least two) at intraabdominal aortic repair (five patients) or to avoid exploration of the abdomen after extensive retroperitoneal dissection or radiation (four patients). Surgical technique involved a seventh interspace thoracotomy with a transdiaphragmatic retroperitoneal anterior axillary line tunnel to the left groin.

RESULTS

There was no perioperative mortality. The mean hospital visit was 15.1 days and intensive care stay 4.3 days. There was no perioperative myocardial infarction, stroke, or renal failure that necessitated dialysis. With a follow-up period of 1 to 121 months (mean 44), the 4-year patency rate was 100%. A single graft failed at 49 months but was renewed by thrombectomy and femorofemoral bypass. Thus the extended patency rate was 86%, but the secondary patency rate remained 100% throughout. Since the thoracic operations, patients have required five femoropopliteal, three femorotibial, two profunda, and two femorofemoral operations.

CONCLUSIONS

Descending thoracic aorta-to-femoral artery grafting is a safe, extremely durable arterial bypass configuration. It is an excellent reconstruction for survivors of aortic graft infection, those who have had multiple failures of aortic grafts, and patients for whom abdominal exploration would be hazardous.