Biomedical subjects
Publications and source records attributed to W D Turnipseed.
A minimally invasive surgical technique for repair of aortic aneurysms and aortoiliac occlusive disease was studied. A small periumbilical incision, nondisplacement of the small bowel outside the abdominal cavity, and hand-sewn anastomoses are performed without laparoscopic assistance. This technique may reduce the duration of hospital stay.
PURPOSE: Aneurysms of the visceral arteries are infrequently encountered. Many are found incidentally and are thought to have a benign outcome. To better characterize these lesions and their clinical course, we reviewed our experience with visceral artery aneurysms (VAAs) at a single institution. METHODS: A retrospective analysis of all VAAs diagnosed at our institution over the past 10 years was performed. The presentation, management, and outcome of therapy was examined for each patient. RESULTS: Thirty-four VAAs in 26 patients were diagnosed over the past 10 years. Four patients had multiple VAAs: splenic (17), hepatic (7), celiac (3), superior mesenteric (2), gastroduodenal (2), pancreaticoduodenal (1), right gastric (1), ileal (1) artery aneurysms. Associated aneurysms were found in 31% of patients and involved the thoracic aorta (3 patients), abdominal aorta (4 patients), renal arteries (2 patients), iliac artery (3 patients), lower extremity (1 patient), and intracranium (1 patient). In 15 patients (58%), VAAs were detected before rupture by chance or because abdominal symptoms resulted in diagnostic evaluation. Eight of these underwent elective surgery, and there were no deaths. Of those 15 patients with known VAAs, one patient died of rupture and hemorrhage from an untreated splenic artery aneurysm. Eleven patients (42%) presented unexpectedly with rupture, and two died despite prompt surgical treatment. The mortality rate in patients who had ruptured VAAs was 25%, including those who presented with ruptured aneurysms and those observed whose aneurysms eventually ruptured. CONCLUSIONS: Aneurysms of the visceral arteries are rare but important vascular lesions. Associated aneurysms are common. Because of the risk of rupture, often with a fatal outcome, an aggressive approach to the treatment of VAA is essential.
PURPOSE: In this study we evaluated the clinical and economic impact of minimal incision aortic surgery (MIAS) for treatment of patients with abdominal aortic aneurysms (AAAs) and aortoiliac occlusive disease (AIOD). METHOD: Fifty patients with either AAA (34) or AIOD (16), prospectively treated with the MIAS technique, were compared with 50 patients (40 AAA and 10 AIOD) treated in the same time period with long midline incision and extracavitary small bowel retraction. MIAS was also compared with a cohort of 32 patients with AAA treated by means of endoaortic stent-grafts. Outcomes and cost (based on metric mean length of stay) were compared for the open and endoaortic techniques. RESULTS: Patients who experienced no perioperative complications after the MIAS or endovascular repair technique had shorter hospital stays than patients with uncomplicated aortic repairs performed with a traditional long midline abdominal incision (3 days vs 3 days vs. 7.2 days). Hospital stay was also significantly shorter for the less invasive procedures when perioperative complications were included (4.8 days vs. 4.3 days vs 9.3 days). The MIAS and endovascular aortic repair groups had a shorter intensive care unit stay (< or = 1.0 day) and a quicker return to general dietary feeding (2.5 days) than patients treated with standard open repair (1.8 days, 4.7 days). The overall morbidity for the MIAS technique (14%) and endovascular technique (21%) was not significantly different from standard open repair (24%). The mortality rate for the different treatment groups was equivalent (MIAS, 2%; endovascular repair, 3%; standard repair, 2%). The MIAS was more cost-efficient than standard open repair ($12,585 vs $18,445) because of shorter intensive care unit and hospital stay and was more cost-efficient than endoaortic repair ($12,585 vs $32,040) because of reduced, direct intraoperative costs. CONCLUSIONS: MIAS is as safe as standard open or endovascular repair in the treatment of AAA and AIOD. MIAS is more cost-efficient than standard open or endoaortic repair.
This prospective nonrandomized study assessed clinical outcomes of a minilaparotomy technique (MLT) used for elective graft repair of infrarenal aortic aneurysm (AAA) and/or aortoiliac occlusive disease (AIOD). Twenty-three patients requiring infrarenal AAA or aortofemoral bypass underwent a small periumbilical midline incision, nondisplacement of the small bowel, and a traditional vascular anastomosis. Results from these procedures were compared with those from contemporaneous procedures performed in the standard transabdominal (STA) fashion (n = 21). Age, weight, and comorbid conditions were comparable between groups. Patients requiring concomitant renal, mesenteric, or infrainguinal revascularization were excluded. Operating time, length of stay in the intensive care unit (ICU), number of oral feeding times, and length of hospital stay were recorded. There were no significant differences in age, operative time, or aneurysm size between the MLT and STA groups. With the MLT then were significant decreases in ICU stay (1 vs. 1.8 days), length of time to return to a general diet (3 vs. 4.7 days), and length of stay (4.9 vs. 7.3 days.) Morbidity and mortality were not statistically different between groups. Patients undergoing the MLT have reduced ICU and hospital stay, and decreased post operative ileus. The MLT does not increase operating room costs or require expensive laparoscopic equipment or the extended postoperative radiographic surveillance needed after endovascular repair.
BACKGROUND: This study evaluated a less invasive technique for exposure of the infrarenal aorta and its impact on the treatment of patients with abdominal aortic aneurysms (AAA) or aortoiliac occlusive disease (AIOD), or both. METHODS: Forty patients with AAA (26), aneurysmal extension into the iliac arteries (6), or AIOD (8) were prospectively selected for minilaparotomy aortic exposure and repair using a small periumbilical midline incision (< or =10 cm); intra-abdominal, nondisplaced retraction of the small bowel; and conventional hand-sewn vascular anastomoses. Perioperative comparisons with a contemporary group of AAA patients treated with long, open midline incision and extracavitary small bowel retraction were made. RESULTS: There was no significant difference between the minilaparotomy and open surgical control groups for operating room time; intraoperative, perioperative morbidity; or mortality. Significant differences were documented between the minilaparotomy and the control group with regard to stay in the intensive care unit (days; 1.0+/-1.2 versus 1.8+/-1.5); return to general diet (days; 3+/-1.3 versus 4.7+/-2.8); and length of stay (days; 4.9+/-1.8 versus 7.3+/- 3.4). CONCLUSIONS: Minilaparotomy exposure is safe and effective for treatment of infrarenal AAA and AIOD. This technique maintains quality outcome while reducing postoperative ileus, hospital stay, and resource utilization.
Groin wound infections can jeopardize patency and function of vascular bypass grafts anastomosed to the femoral artery. Attempts to salvage vascular reconstructions threatened by perigraft infection often fail because of inadequate debridement of surrounding infected soft tissue or because of an inability to cover an exposed graft with sufficient healthy tissue. In selected circumstances, use of rotational myocutaneous flaps makes it possible to salvage vascular grafts threatened by localized wound infection.
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This study measured the responses of both extracranial (internal carotid arteries) and intracranial (middle cerebral/angular, basilar arteries) intravascular arterial volume flow rates to acetazolamide using phase-contrast magnetic resonance angiography. Twenty-eight newly studied patients were subdivided into four groups: Group I--Nonocclusive, asymptomatic (n = 7, or 14 carotid and middle cerebral/angular artery sides); Group II--unilateral carotid transient ischemic attacks, nonhemodynamic (embolic), varying stenoses (n = 11); Group III--unilateral carotid transient ischemic attacks, hemodynamic, varying stenoses (n = 5); and Group IV--unilateral carotid occlusion, asymptomatic (n = 5). The data were separated into nonischemic and ischemic sides so as to illustrate group differences based on vasodilatory responses to acetazolamide. For example, the percent change in volume flow rates over baseline values for the ischemic-side middle cerebral arteries of Group III was significantly the lowest of all of the vasodilatory responses (-25 +/- 11% vs 40 +/- 14% for group II ischemic middle cerebral/angular artery sides, p = 0.008). Group III patients also had significantly lower standing blood pressures (p = 0.012), higher number of transient ischemic attacks (p = 0.008), and shorter duration of events (p = 0.013). Determinations of volume flow rate continue to assist in determining the degree of hemodynamic compromise of a particular vascular territory.
Long-term outcome was studied in 233 patients who had undergone renal artery revascularization (51 with balloon angioplasty, 182 with surgery) between 1976 and 1992. Patients (excluding renal transplants) were treated for renal vascular hypertension without or with renal insufficiency (serum creatinine > 1.6 mg/dl. All patients still alive (n = 188) were contacted to determine current blood pressure, medications, serum creatinine, and subsequent significant medical events. In patients who had died the cause of death was determined and renal function status at the time of death noted from medical records. Some follow-up information was obtained on all 233 patients; follow-up serum creatinine data were obtained in 193 (82.8%) patients. Some 24 patients (10.3%) became dialysis-dependent. Using a multiple logistic regression analysis only, preoperative creatinine maintained significance (P < 0.001) for increased dialysis risk. There was no statistically significant association of dialysis for type of revascularization (percutaneous transluminal angioplasty, autogenous artery, saphenous vein, endarterectomy or synthetic material), simultaneous or previous aortic or other vascular surgery (carotid endarterectomy, femoropopliteal bypass, etc.), pathology (atherosclerosis or fibromuscular dysplasia), number of renal arteries stenosed or treated, length of follow-up, age, coronary artery disease, congestive heart failure, stroke, chronic lung disease or type II diabetes. It is concluded that, in patients with renal artery stenosis, the timing of renal artery revascularization relative to the level of renal function is the most important determinant for long-term renal salvage.
PURPOSE: This study was designed to determine whether magnetic resonance angiography (MRA) will allow preoperative management decisions without the need for contrast arteriography in patients with lower extremity ischemia caused by infrainguinal arterial occlusive disease. METHODS: Forty-five patients with lower extremity ischemia in 50 limbs were evaluated by both two-dimensional time-of-flight MRA and intraarterial digital subtraction angiography (DSA) between February 1992 and June 1995. Independent management plans were based on clinical presentation, pulse volume recordings, and separate reviews of the MRA and DSA. RESULTS: Of 50 limbs, 23 required arterial bypass, 19 percutaneous transluminal angioplasty, 5 patch angioplasty, and 3 amputation. MRA and DSA correlated exactly in 89.5% of infrainguinal arterial segments, whereas interpretations disagreed in 10.5% of arterial segments. Mismatches that had an influence on patient treatment decisions occurred in only 8 (2.3%) of 352 arterial segments. Independent MRA- and DSA-based revascularization plans agreed in 45 (90%) extremities. MRA predicted the level of arterial reconstruction in all 23 limbs that required arterial bypass. MRA identified focal stenoses amenable to percutaneous transluminal angioplasty in 18 (94.7%) of the 19 limbs that ultimately underwent percutaneous transluminal angioplasty. A strategy of preoperative planning by MRA with confirmatory intraoperative arteriography would represent a 31% cost savings per patient at our institution while eliminating the morbidity of preoperative DSA. CONCLUSIONS: When used in combination with the patient's physical examination and segmental limb pressures with plethysmography, MRA is sufficient for planning infrainguinal arterial bypass procedures and selecting patients for percutaneous transluminal angioplasty.
Cerebral vasodilatory testing provides an important measure of both the hemodynamic significance of arterial occlusive disease and the adequacy of collateral pathways. This study measured the extracranial intravascular volume flow rate response to acetazolamide using phase-contrast magnetic resonance angiography. From 10 patients with unilateral carotid transient ischemic attacks (TIAs), a total of 18 extracranial carotid arteries (10 symptomatic, 8 asymptomatic, 2 occluded) and 19 extracranial vertebral arteries were studied. Patients were free of large-vessel intracranial stenoses, evident areas of ischemic infarction, evident areas of nonspecific white matter change, and hemodynamic or low-flow induction of TIA symptomatology. Asymptomatic carotid volume flow rates rose from 151 +/- 19 (standard error of mean) to 220 +/- 26 ml/min while symptomatic flow rates rose from 106 +/- 22 to 145 +/- 25 ml/min. Dominant vertebral volume flow rates rose from 128 +/- 23 to 160 +/- 22 ml/min while nondominant rates rose from 40 +/- 12 to 61 +/- 15 ml/min. Carotid volume flow rates were inversely proportional to percent stenosis for both baseline (r = 0.51, p < 0.02) and acetazolamide (r = 0.81, p < 0.001) data. Baseline-plus-acetazolamide volume flow rate techniques safely measure intravascular vasodilatory responses. Intracranial measurement techniques are being developed to further study cerebrovascular reserve using phase-contrast magnetic resonance angiography.
PURPOSE: The purpose of this study is to evaluate the effects of increased compartment pressure on anterior tibial arteriovenous flow patterns and to determine whether mechanical and biochemical properties of fascia are responsible for compartment pressure abnormalities. METHODS: Twenty patients with chronic anterior compartment syndrome (CACS) and 20 age-matched control subjects had compartment pressure measurements and analysis of tibial arterial and venous flow before and after fasciectomy. Fascia specimens were evaluated for thickness, stress failure, structural stiffness, and total collagen content and prevalence of collagen cross-linkage. RESULTS: Pressures were significantly elevated in patients with CACS versus control subjects (23.8 mm Hg vs 6 mm Hg). No significant difference in tibial arterial flow could be detected in either group (43 cm/sec mean vs 41.9 cm/sec mean). Venous drainage was severely impaired in patients with CACS but not in control subjects. CACS fascia was thicker and stiffer than control fascia specimens (0.35 mm +/- 0.12 mm, 109 +/- 65 MN/mm; versus 0.22 mm +/- 0.06 mm; 60.3 +/- 22 MN/mm). Fasciectomy normalized postoperative compartment pressures and improved venous drainage. Collagen content per unit mass was similar for both CACS and control fascia specimens, although collagen cross-linking was significantly lower in the CACS fascia than in the controls. CONCLUSIONS: Tibial venous drainage is impaired, but arterial flow is not in patients with CACS. Fascia thickness and structural stiffness can account for increased pressure in CACS compartments. Collagen content and cross-linkage are unrelated to fascia stiffness or thickness. Postoperative improvement in vascular hemodynamics and reduction in compartment pressure is caused by increased capacitance in the compartment after fasciectomy.
PURPOSE: Intimal hyperplasia is a common cause of obstructive stenosis after arterial reconstructive procedures. It has been postulated that growth factors elaborated by vascular wall cells regulate fibroproliferative changes that can cause graft failure. This study characterizes transforming growth factor beta-1 (TGF-beta 1) and platelet-derived growth factor-A chain (PDGF-A) mRNA transcript profiles and their temporal relationship to the development of intimal hyperplasia in vein grafts. METHODS: Epigastric vein-to-common femoral artery interposition grafts were performed in male Lewis rats (350 to 450 gm) with standard microsurgical techniques. Grafts were harvested at 1 and 4 hours, 1 and 4 days, and 1 and 2 weeks (n = 5/time). Graft RNA was extracted, reverse-transcribed, and amplified by polymerase chain reaction with sense/antisense primers for TGF-beta 1 and PDGF-A (30 cycles). Polymerase chain reaction fragments were confirmed by Southern hybridization. RESULTS: Variable induction of TFG-beta 1 gene transcription was evident in vein grafts at 1 and 4 hours, with prominent mRNA expression from 1 day to 2 weeks. PDGF-A mRNA was detected in ungrafted control veins but was downregulated at 1 hour and absent at 4 hours after grafting. PDGF-A transcription was upregulated by 1 day, with prominent expression from 4 days to 1 week. Early loss of PDGF-A mRNA correlated with the early denudation of the endothelium, whereas upregulation by 4 days was preceded by TGF-beta 1 mRNA expression. CONCLUSIONS: Upregulation of TGF-beta 1 and PDGF-A mRNA expression is detected in vein grafts before the development of a quantifiable neointima, which occurs by 2 weeks in our model. This suggests a role for these growth factors in the development of vein graft intimal hyperplasia.
PURPOSE: This report summarizes our experience with the use of cerebral spinal fluid drainage (CSFD) and naloxone for prevention of postoperative neurologic deficit (paraplegia or paraparesis). METHODS: We reviewed 110 consecutive patients with 86 thoracoabdominal aneurysms and 24 thoracic aneurysms. The status of 47 patients (43%) was acute (rupture or dissection), and the status of 52 (47%) was Crawford type I or II. None of the patients had intercostal artery reimplantation. There were two patient groups for analysis of neurologic deficit risk. Group A (61 patients) received naloxone and CSFD, and group B (49 patients) did not. RESULTS: One deficit occurred in group A and 11 deficits occurred in group B (p = 0.001). By multiple logistic regression analysis, the variables acute status, Crawford type II, or group B classification were significant factors for deficit risk. Use of the same logistic regression analysis on the subgroup of 47 patients with acute aneurysms and 33 patients with Crawford type 2 aneurysms confirmed the protective effect of combined CSFD and naloxone (group A) and that clinical presentation and extent of aorta replaced are the primary risk factors for development of deficit. To test this conclusion we developed a highly predictive model (correlation coefficient 0.997 with 16 series of thoracoabdominal aneurysms) for neurologic deficit. We applied our data to this model. Group B had the predicted number of deficits, and group A had substantially fewer deficits than predicted. CONCLUSIONS: We conclude that the combined use of CSFD and naloxone offers significant protection from neurologic deficits in patients undergoing thoracoabdominal and thoracic aortic replacement.
BACKGROUND: A controversy has evolved as to which therapy, thrombolysis or thromboembolectomy, represents the optimal initial treatment for acute native artery occlusion. METHODS: Forty-eight cases of acute class I or II limb ischemia caused by native artery occlusion were retrospectively analyzed between 1988 and 1993. Nineteen of the patients were initially treated with thrombolysis (group 1), and 29 underwent thromboembolectomy (group 2). RESULTS: Initial clinical improvement was seen in 11 (57.9%) of 19 extremities in group 1, with complete clot resolution in 21%, partial lysis in 47.4%, and no angiographic improvement in 31.6%. Significantly superior results were achieved in group 2; 28 (97%) of 29 limbs showed clinical improvement after initial surgical therapy (p = 0.001). Limb salvage was 88.2% in group 1 and 96.6% in group 2 (p = 0.5). Adjunctive procedures for limb salvage were necessary in 10 (52.6%) of 19 limbs in group 1 compared with only five (17.2%) of 29 limbs in group 2 (p = 0.013). Perioperative mortality was 10.5% and 10.3% (p = 1.0), whereas major postoperative complications occurred in 63.2% and 37% of patients in groups 1 and 2, respectively (p = 0.14). Hospital and professional patient charges were analyzed for the 12 most recent patients from each group. Total mean charges per patient were higher in group 1 ($45,171) than in group 2 ($24,898) (p = 0.046). CONCLUSIONS: Patients initially treated surgically achieved better immediate clinical results with significant cost savings and without significant differences in morbidity, mortality, or limb salvage compared with patients treated initially by thrombolysis.
BACKGROUND: Intimal hyperplasia (IH), a cause of early graft failure, may be regulated by leukocyte-elaborated cytokines. We investigated leukocyte infiltration and cytokine gene expression in vein grafts. METHODS: Epigastric vein to femoral artery grafts were performed in Lewis rats and harvested on day 4 and weeks 1, 2, 4, 8, and 12. Neointimal areas were measured by computerized planimetry. Immunoperoxidase staining identified for macrophages, CD4+, CD8+, and major histocompatibility complex class II+ cells. Graft RNA was used in reversetranscription-polymerase chain reaction with interleukin (IL)-1 alpha, IL-2R, monocyte chemoattractant protein-1, and transforming growth factor-beta primers. RESULTS: IH was measurable at 2 weeks; the perianastomotic regions displayed greater IH than the midgraft (p < 0.05). MANOVA indicated strong location (p = 0.0001) and time (p = 0.0009) effects. Immunocytochemistry showed inflammatory infiltrates from 4 days to 4 major histocompatibility complex class II+ and primarily monocyte/macrophages, with less frequent T lymphocytes (CD4+ > CD8+). IL-1 alpha messenger RNA is expressed early, disappearing after 4 weeks. Monocyte chemoattracta t protein-1 mRNA is constitutively expressed, with up-regulation at 4 days to 4 weeks. IL-2R mRNA levels fluctuate; transforming growth factor-beta is always expressed, peaking at 4 days to 4 weeks. CONCLUSIONS: Gene expression of cytokines thought to modulate IH is up-regulated early in vein grafts. This coincides with graft infiltration by activated leukocytes before and during the development of IH.
PURPOSE: Advances in cerebral vascular imaging suggest that patients with critical levels of carotid artery stenosis (> 70%) who have symptoms can be identified accurately and necessary information about the intracranial and extracranial circulation obtained before surgery without conventional angiography. We have used carotid duplex imaging in combination with magnetic resonance angiography (MRA) to evaluate 20 patients with symptomatic ipsilateral high-grade carotid stenosis. METHODS: All patients underwent CT and magnetic resonance imaging brain scans, as well as MRA and conventional arteriography of the cerebral circulation. Magnetic resonance angiograms were obtained with two-dimensional phase contrast and time-of-flight techniques. Phase contrast was used for intracranial vascular imaging and for determining qualitative flow velocities and the direction of blood flow in the circle of Willis. Two-dimensional time of flight was used to assess the carotid bifurcations. RESULTS: Twenty patients with symptoms (six with strokes, 11 with transient ischemic attacks, and three with amaurosis fugax) had duplex evidence of high-grade carotid stenoses. Computed tomographic and magnetic resonance brain scans were positive for cerebral infarction in six patients with clinical strokes. Comparison of MRA with conventional angiography was 91% accurate for high-grade stenoses and occlusions (sensitivity 100% and specificity 90% for stenosis; sensitivity/specificity was 100% for complete occlusion). Comparison of duplex imaging with conventional angiography demonstrated 86% accuracy for detection of severe stenosis or occlusion (sensitivity 94% and specificity 89% for stenosis; sensitivity and specificity were 100% for complete occlusion). CONCLUSIONS: This study suggests that combined use of MRA and duplex imaging is accurate for detection and evaluation of high-grade carotid stenoses in patients with symptoms.