W. John Sharp

A prospective study of the incidence and natural history of femoral vascular complications after percutaneous transluminal coronary angioplasty

Over a 14-month period patients undergoing 144 percutaneous transluminal coronary angioplasty procedures were evaluated for the presence of complications at the femoral puncture site. After percutaneous transluminal coronary angioplasty each patient was examined by a surgeon, and then a color-flow duplex scan of the groin was obtained. On the initial scan eight pseudoaneurysms, three arteriovenous fistulas, one combined arteriovenous fistula-pseudoaneurysm, and one thrombosed superficial femoral artery were detected for a major vascular complication rate of 9%. Pseudoaneurysm formation was associated with the use of heparin after removal of the arterial sheath. Seven pseudoaneurysms (initial extravascular cavity size range 1.3 to 3.5 cm) were followed with weekly duplex scans, and all thrombosed spontaneously within 4 weeks of detection. The three patients with isolated arteriovenous fistulas were each followed for at least 8 weeks, and the arteriovenous fistulas persisted. Early surgical intervention for postcatheterization femoral pseudoaneurysms is usually unnecessary as thrombosis often occurs spontaneously. We would advocate an operative approach for pseudoaneurysms that are symptomatic, expanding, or associated with large hematomas. Iatrogenic femoral arteriovenous fistulas should be considered for elective repair, but this may be delayed for several weeks without adverse sequelae.

Regulation of Transcription Factor Pdr1p Function by an Hsp70 Protein in Saccharomyces cerevisiae

ABSTRACT Multiple or pleiotropic drug resistance in the yeastSaccharomyces cerevisiae requires the expression of several ATP binding cassette transporter-encoding genes under the control of the zinc finger-containing transcription factor Pdr1p. The ATP binding cassette transporter-encoding genes regulated by Pdr1p include PDR5 and YOR1, which are required for normal cycloheximide and oligomycin tolerances, respectively. We have isolated a new member of the PDR gene family that encodes a member of the Hsp70 family of proteins found in this organism. This gene has been designated PDR13 and is required for normal growth. Overexpression of Pdr13p leads to an increase in both the expression of PDR5 and YOR1 and a corresponding enhancement in drug resistance. Pdr13p requires the presence of both the PDR1 structural gene and the Pdr1p binding sites in target promoters to mediate its effect on drug resistance and gene expression. A dominant, gain-of-function mutant allele ofPDR13 was isolated and shown to have the same phenotypic effects as when the gene is present on a 2μm plasmid. Genetic and Western blotting experiments indicated that Pdr13p exerts its effect on Pdr1p at a posttranslational step. These data support the view that Pdr13p influences pleiotropic drug resistance by enhancing the function of the transcriptional regulatory protein Pdr1p.

Reversal of Renal Failure and Paraplegia After Thoracoabdominal Aneurysm Repair

Repair of ruptured thoracoabdominal aortic aneurysms is complicated by high rates of perioperative paraplegia, renal insufficiency, and mortality. This report describes a patient with a ruptured thoracoabdominal aortic aneurysm in whom preoperative acute renal failure was reversed with hemodialysis, aortic replacement, and renal revascularization. Prompt cerebrospinal fluid drainage reversed delayed-onset postoperative paraplegia and led to immediate, complete neurologic recovery.

Suprarenal Clamping Is a Safe Method of Aortic Control when Infrarenal Clamping Is not Desirable

We evaluated the safety of suprarenal aortic clamping in patients with abdominal aortic aneurysm (AAA) treated by open aortic replacement by retrospectively reviewing all patients who underwent elective AAA replacement at a university hospital from 1993 until 2003. We reviewed 249 patient charts and divided them into three groups according to the clamp location during aortic replacement: group 1, infrarenal clamp group (n = 185); group 2, suprarenal clamp group (n = 52); and group 3, supraceliac clamp group (n = 12). Groups 1 and 2 were compared with respect to risk factors, intraoperative events, and postoperative events. Statistical analysis was done using Wilcoxons rank-sum test, chi-squared test, and Fishers exact test. Risk factors were comparable in groups 1 and 2 except for weight, which was higher in group 1. Intraoperative urine output, hypotensive episodes, and use of renal protective drugs were comparable in the two groups. Operation time, blood loss, and use of IV fluids were all significantly higher in group 2, while total aortic clamp time was higher in group 1. Postoperative events were comparable except for postoperative peak creatinine, intensive care unit length of stay, and postoperative length of stay, which were higher in group 2; however, discharge creatinine was comparable without a significant difference. Suprarenal clamping is a safe method of aortic control during open AAA replacement surgery. The selection of clamping site should be individualized according to the intraoperative anatomy. Supraceliac clamping is not necessarily the preferable method of aortic control when the infrarenal location is not suitable for clamping.

Graft irradiation abrogates graft-versus-host disease in combined pancreas-spleen transplantation.

A model of combined pancreas-spleen transplantation (PST) was studied in LBN F1 recipients of Lewis grafts in order to evaluate the efficacy of pretransplant graft irradiation in preventing lethal graft-versus-host disease (GVHD). Recipients of unmodified PST uniformly developed severe GVHD and died (MST = 16.7 +/- 3.8 days). Whole body donor irradiation with either 500 or 250 rad prevented lethal GVHD. Similarly, ex vivo graft irradiation with either 1000 or 500 rad also resulted in normal weight gain, graft function, and host survival for the 6-week study period. Conversely, delay of graft irradiation until 3 days after transplantation failed to prevent this complication (MST = 15.8 +/- 3.7 days). Recipients of irradiated grafts displayed glucose tolerance tests that were identical to those in the control group indicating that the doses of radiation employed in these experiments were not deleterious to islet function. Irradiated spleen grafts appeared histologically normal at 6 weeks after transplantation. Cells derived from these grafts failed to stimulate lymph node enlargement in a popliteal lymph node assay for GVHD, suggesting that these spleens may have become repopulated with host cells. These experiments confirm that PST has the potential to cause lethal GVHD and suggest that pretransplant graft irradiation may be used to prevent its occurrence.

Femoral to Above Knee Popliteal Prosthetic Bypass

Various choices are available when selecting a prosthetic bypass to the above knee popliteal artery. The choices include the material, the size and the external support. Whether to use polytetrafluoroethylene (PTFE), polyester graft or human umbilical vein is a matter of surgeon’s preference since none of these grafts has been proven to offer a significant patency advantage over the other. However, the use of larger diameter grafts (8 mm) has been shown to be associated with better patency rates than smaller diameter grafts. Although there is no strong evidence to support using externally supported grafts to the above knee popliteal artery, our preference has been to use 8-mm PTFE ringed grafts to decrease the possibility of kinking during tunneling. Newer PTFE grafts with various features such as carbon lining or heparin coated and specially designed cuffs continue to be introduced into the market. Whether they will provide better patency rates is yet to be proven.

Femoral to Below Knee Popliteal Bypass with Reversed Great Saphenous Vein

The patient is placed supine on the operating table. The arms are placed at 80°. Normal bony prominences are padded. After placement of the appropriate line and induction of anesthesia, a Foley catheter is placed under sterile technique. The patient’s lower abdomen and both lower extremities are circumferentially prepped and draped. The great saphenous vein has been assessed preoperatively by duplex ultrasound and its location mapped with ink. Preoperative antibiotics are administered prior to skin incision.

Femoral to Posterior Tibial/Peroneal Artery In Situ Bypass

The hallmark of in situ bypasses is to leave the vein in its bed, in situ, to minimize the damage and ischemia that can occur during vein harvesting. Furthermore it provides for a better size match between the bypass and the target infrapopliteal vessels. The disadvantages include the risk of trauma from the valvulotomy and a higher incidence of wound complications. Wound complications increase the vulnerability of the vein bypass to thrombosis, desiccation and disruption if it becomes exposed. Various methods have been devised to construct an in situ bypass. Similarly various valvulotomes are available to disrupt the valves, and various techniques are available to occlude the venous branches which if left alone can progress to become arteriovenous fistulae. The procedure described here is the preferred method used at the University of Iowa. This method involves exposing the entire vein, arterializing the vein, using the retrograde Mills valvulotome to disrupt the valves under direct vision and constructing the distal anastomosis.

Subhepatic Inferior Vena Cava Resection with Left Renal Vein Reimplantation to a Large Ascending Lumbar Collateral A Case Report

A 6-year-old girl, postnephrectomy for a Wilms tumor, demonstrated a recurrence involving the liver and inferior vena cava by ultrasound. Reoperation for removal of the recurrence required further resection and a bypass using an ascending lumbar collateral as an outflow vessel.

Repair of a Traumatic Pseudoaneurysm of a Thoracoaortofemoral Bypass A Case Report

Ten years after placement of a thoracofemoral graft for aortoiliac occlusive disease, a mid graft pseudoaneurysm was identified following new trauma to the left flank. An aortogram confirmed the pseudoaneurysm. An initial attempt at repair with an endovascular stent failed; an open repair was required.