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Biomedical subjects

John A Kern

Publications and source records attributed to John A Kern.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of systemic and retrograde delivery of adenosine A2A agonist for attenuation of spinal cord injury after thoracic aortic cross-clamping.

BACKGROUND: Paraplegia remains a devastating complication of thoracic aortic surgery, which has been attenuated by retrograde adenosine and systemic adenosine A2A receptor activation. We hypothesized that despite retrograde spinal perfusion of an adenosine A2A agonist (ATL-146e), systemic therapy produces superior spinal cord protection with reduced inflammation. METHODS: Forty pigs underwent 30-minute thoracic aortic cross-clamping. Pigs received: no therapy (control); retrograde saline (retrograde control); retrograde ATL-146e; systemic ATL-146e; systemic ATL-146e with retrograde saline; or systemic and retrograde ATL-146e. Retrograde therapies were given during ischemia. Systemic ATL-146e (0.06 microg.kg(-1).min(-1)) was given intravenously for 3 hours at reperfusion. At 24 hours, motor function was assessed using the Tarlov scale. Tissue was analyzed for neuronal viability, microtubule-associated protein-2 expression, and neutrophil sequestration (myeloperoxidase activity). RESULTS: Four pigs received retrograde barium showing both radiographic and histologic spinal cord perfusion. Tarlov scores at 24 hours were significantly improved versus both control groups in all ATL groups except the combined ATL-146e group (all p < 0.05). Neuronal viability by hematoxylin and eosin stain was significantly preserved in systemic ATL groups compared with both control groups (all p < 0.05). Microtubule-associated protein-2 expression was significantly preserved compared with both control groups in all systemic ATL groups. Systemic ATL significantly lowered myeloperoxidase activity versus both control groups (p < 0.01). CONCLUSIONS: Both retrograde and systemic ATL-146e therapies attenuate ischemic spinal cord injury, but combining the two routes was less effective. Given comparable results between the two routes and the simplicity of systemic delivery, peripheral venous ATL-146e at reperfusion should be preferred for spinal cord protection in thoracic aortic surgery.

Adenosine A2 Receptor Agonists↗
PubMed2006

Does preoperative ejection fraction predict operative mortality with left ventricular restoration?

BACKGROUND: Ischemic cardiomyopathy and aneurysmal disease have been treated surgically with coronary artery bypass grafting in the past. The Dor technique for left ventricular restoration has demonstrated improved outcomes in patients with ischemic, akinetic ventricles. Our hypothesis was that even marked reduction in preoperative cardiac function (ejection fraction < .25) would not correlate with worse outcomes since the ventricle would be reshaped to improve function. METHODS: A retrospective analysis was performed on all patients who had undergone ventricular restoration with the Dor procedure from January 1996 through September 2005. Patients with a preoperative ejection fraction (EF) < .25 and those with a EF > or = .25 were compared. All Society of Thoracic Surgeons database characteristics, mortality, length of stay (LOS), and need for intraaortic balloon pump (IABP) were analyzed. RESULTS: The study included 89 patients (69 men, 20 women), 28 of whom had preoperative EFs < .25 (mean, .183 +/- .035; range, .08 to .25) and 61 had an EF > or = .25 (mean, .334 +/- .074; mean, .25 to .45). Overall operative mortality was 3.4% (3/89), with no statistically significant difference between the two groups (3.6% versus 3.3%). LOS was 7.4 +/- 3.6 days versus 8.9 +/- 15.6 days (p = NS), and need for IABP was 39.2% versus 8.1% (p < 0.05). Overall 5-year survival was 82%. Five-year survival in the EF < .25 cohort was 69.6% versus 88.3% in the EF > or = .25 cohort (p = 0.066). CONCLUSIONS: Ventricular restoration with the Dor technique is a safe procedure. Marked reduction in ejection fraction is not a contraindication to left ventricular restoration; however, increased usage of IABP should be anticipated.

Adult↗
PubMed2006

Endoscopic versus open saphenous vein harvest for femoral to below the knee arterial bypass using saphenous vein graft.

BACKGROUND: Although the use of endoscopic vein harvest (EVH) in coronary artery bypass grafting is accepted, few studies have documented the implementation of EVH in peripheral vascular disease surgery. We hypothesized that EVH improves outcomes compared with open vein harvest (OVH) in patients undergoing femoral to below the knee arterial bypass surgery. METHODS: The charts of 144 consecutive patients undergoing infrainguinal bypass surgery over the course of 27 months were reviewed. A femoral to below the knee arterial bypass with saphenous vein was done in 88 patients (29 had EVH, 59 had OVH). The preoperative characteristics evaluated were age, gender, renal function, history of diabetes, hypertension, tobacco use, and previous infrainguinal bypass surgery on the affected side. End points included wound complications, length of hospital stay, operative time, angiographic and operative interventions for graft occlusion, patency rates, limb salvage, acute renal failure, myocardial infarction, and death. RESULTS: Patient characteristics and demographics were similar in the EVH and OVH groups. No operative intervention for occlusion was required in the EVH group (0/29) compared with 13.4% in the OVH group (8/59) (P = .03). At the mean follow-up time of 21 months, primary patency rate was 92.8% in the EVH group and 80.6% in the OVH group (P = .12). No significant differences were found between the EVH and OVH groups in postoperative complications, length of hospital stay, operative time, patency rates, limb salvage, and death. CONCLUSION: Despite our initial concerns of damaging the venous conduit with a minimally invasive approach to saphenous vein harvest, EVH in our experience has resulted in a trend toward improved patency rates and decreased infectious wound complications while affording the benefit of improved cosmesis. An endoscopic approach results in smaller incisions, decreased interventions for occlusion, and improved outcomes compared with OVH. EVH is the procedure of choice for harvesting saphenous vein for femoral to below the knee arterial bypass surgery.

Endoscopy↗
PubMed2006

Functional and cytoarchitectural spinal cord protection by ATL-146e after ischemia/reperfusion is mediated by adenosine receptor agonism.

BACKGROUND: ATL-146e protects the spinal cord from ischemia/reperfusion injury, presumably via adenosine A(2A) receptor activation, but this relationship remains unproven. We hypothesized that spinal cord functional and cytoarchitectural preservation from ATL-146e would be lost with simultaneous administration of the specific adenosine A(2A) antagonist ZM241385 (ZM), thus proving that adenosine A(2A) receptor activation is responsible for the protective effects of this compound. METHODS: New Zealand White rabbits underwent 45 minutes of infrarenal aortic cross-clamping. Groups (n = 10) included sham, ischemia, ischemia plus ATL-146e (ATL-146E), ischemia plus ZM, or ischemia with both compounds (agonist-antagonist). Tarlov scores were recorded every 12 hours. After 48 hours, the spinal cord was fixed for histology and microtubule-associated protein 2 immunohistochemistry. RESULTS: Tarlov scores at 48 hours were significantly better in the sham and ATL-146E groups (5.0 and 3.9, respectively) compared with the other three groups (all < or =1.3; P < .001). On hematoxylin and eosin, neuronal viability was higher in the sham, ATL-146E, and agonist-antagonist groups compared with the control and ZM groups (P < .05). Microtubule-associated protein 2 expression was preserved in the sham and ATL-146E groups but was lost in the ATL + ZM, ZM241385, and control groups. CONCLUSIONS: ATL-146e preserves the spinal cord in terms of both cytoarchitecture and function after reperfusion of the ischemic spinal cord, but this preservation is not completely blocked by competitive adenosine A(2A) receptor antagonism. Although ATL-146e does seem to partially function through activation of the adenosine A(2A) receptor, the neuroprotective mechanism may not be limited to this particular receptor.

Adenosine A2 Receptor Agonists↗
PubMed2006

Thoracic aortic endografting is the treatment of choice for elderly patients with thoracic aortic disease.

OBJECTIVE: To assess the effect of age on outcomes following thoracic aortic endografting. SUMMARY BACKGROUND DATA: Endograft therapy for thoracic aortic disease is rapidly evolving. This therapy is less invasive, and elderly patients with significant medical comorbidities are more frequently referred for endografting. We hypothesized that elderly patients over the age of 75 have worse outcomes after thoracic endografting than patients under the age of 75. METHODS: We retrospectively reviewed the charts of the first 42 patients who underwent endografting for thoracic aortic pathology. Charts were reviewed for demographics, comorbid conditions, perioperative complications and death, endoleaks, and results at 3, 6, and 12 months. Preexisting medical conditions were also evaluated to determine if any patient characteristics were associated with adverse outcomes. Perioperative morbidity included cardiac, pulmonary, renal, hemorrhagic, and neurologic (stroke and spinal cord injury) complications. RESULTS: Twenty-four patients were under the age of 75, and 18 patients were 75 or older. Baseline demographics and comorbidities were similar between the 2 groups. There were no differences in operative time, length of stay, perioperative mortality, or the incidence of significant complications between the 2 age groups. Gender, however, was associated with a statistically significant difference between the occurrence of complications, with more women experiencing complications than men (P = 0.026, relative risk = 2.36). One patient (age >75 years) in the entire cohort of 42 (2.4%) suffered a spinal cord injury. At 3 months, endoleaks were more common in the older age group (P = 0.059). CONCLUSION: Endograft therapy for thoracic aortic disease can be performed safely in elderly patients with no significant increase in perioperative morbidity or mortality compared with younger patients. Female gender is associated with a higher likelihood of perioperative complications, regardless of age. The overall incidence of spinal cord injury is very low. Endograft therapy, when anatomically possible, is the treatment of choice for thoracic aortic disease in elderly patients.

Adult↗
PubMed2006

A comparison of adenosine A2A agonism and methylprednisolone in attenuating neuronal damage and improving functional outcome after experimental traumatic spinal cord injury in rabbits.

OBJECT: Steroid agents remain the lone pharmacological treatment in widespread use for acute spinal cord injury (SCI), although their utility remains in dispute in the neurotrauma literature. Adenosine A2A receptor activation with ATL-146e, a selective A2A agonist, has shown potential benefit in treating SCI; however, it has not been compared with the gold standard, methylprednisolone. The authors of this study evaluated ATL-146e and methylprednisolone for their ability to preserve neuronal viability and motor function in experimental SCI. METHODS: New Zealand White rabbits sustained SCI or sham injury via the Allen weight-drop technique. Ten minutes postinjury, animals received ATL-146e (ATL group, 0.06 microg/kg/min intravenously for 3 hours), methylprednisolone (steroid group, 30 mg/kg intravenously), or saline (trauma control group). Hindlimb motor function was recorded every 12 hours using the Tarlov motor grading scale (0, paralysis-5, normal hop). At 48 hours, fixed spinal cord tissue was evaluated for neuronal viability. Hindlimb motor function in animals treated with ATL-146e was equivalent to that of sham-injured animals and was significantly better than that of trauma control animals at all time points and that of steroid-treated animals at 12 hours (p = 0.05). Motor function in steroid-treated animals was worse than in those given ATL-146e and better than that of trauma control animals at later time points, but was not statistically significant (both p > 0.05). Neuronal viability (measured in neurons/hpf) was significantly higher in both treatment groups compared with the trauma control group (12.1 +/- 1.4 neurons/hpf for the ATL and 13.3 +/- 1.4 neurons/hpf for the steroid group compared with 7.5 +/- 1.5 neurons/hpf for the trauma control group; both p < 0.04). Neuronal viability did not differ among ATL-146e-treated, steroid-treated, and sham-injured groups. CONCLUSIONS: The use of ATL-146e is at least as effective as methylprednisolone in preserving function and is equivalent to methylprednisolone in preserving the structure of spinal cord tissue after blunt SCI. Adenosine A2A receptor activation may be an effective treatment for acute SCI while avoiding the adverse effects of steroid agents.

Animals↗
PubMed2006

Optimization of a mouse locomotor rating system to evaluate compression-induced spinal cord injury: correlation of locomotor and morphological injury indices.

OBJECT: Due to the usefulness of mouse genetics, there is a need to improve procedures for producing and assessing spinal cord injury (SCI) in mice. The authors describe an improved locomotor scoring system for evaluating SCI. The modified Basso-Beattie-Bresnahan (mBBB) scoring system for mice is compared with existing procedures as well as histological SCI criteria. METHODS: Mice were subjected to SCI by placing a weight on the cord at T-12 for 5 to 15 minutes after laminectomy to produce spinal cord ischemia. Injury was assessed using mBBB scoring that incorporates elements of the rat BBB and the mouse motor function scoring systems that are best suited for precisely assessing mouse SCI. The mBBB score was found to be more discriminating than the inclined plane test, and in the authors' laboratory it had a significantly lower coefficient of variation than the Basso mouse scale score. The mBBB score is well correlated with sparing of white matter as assessed by eriochrome cyanine staining of myelin. CONCLUSIONS: Weight placement at T-12 in the mouse causes reproducible SCI. A new mBBB scoring system is useful for accurately assessing locomotor dysfunction following SCI in mice and is well correlated with histological assessment of spinal cord white matter.

Animals↗
PubMed2005

Evaluation of an absorbable cyanoacrylate adhesive as a suture line sealant.

BACKGROUND: Previous formulations of cyanoacrylate, though very effective, proved to have too high a tissue reactivity to be used internally. A novel cyanoacrylate compound with less tissue reactivity was recently developed. The objective of this study was to assess this novel cyanoacrylate compound for the use as vascular suture line sealant. MATERIALS AND METHODS: Twelve adult female sheep received a 6 mm PTFE interposition graft in each iliac artery, for a total of 24 grafts. Using oxidized cellulose (Surgicel) as a control, two formulations of a new cyanoacrylate compound (named "compound A" and "compound B") were assessed during this trial. Hemostatic efficiency was measured at the time of operation by the assessment of bleeding time and amount of blood loss. Long-term graft patency was assessed angiographically at 4, 6, and 18 months. Tissue reaction at 2 weeks, 1, 6, and 18 months was assessed grossly by vascular surgeons and microscopically by a blinded pathologist. RESULTS: Average time to hemostasis was 37.6, 50.6, and 219 s in group A, group B, and oxidized cellulose control groups, respectively (P<or=0.001 for both compounds versus control). There were no significant differences between groups with regards to graft patency. Histopathology analysis demonstrated mild to moderate tissue reaction at 2 weeks and 1 month in the cyanoacrylate groups compared with controls at 1 month (ANOVA P=0.004). Mild tissue reaction was seen at 6 months and 18 months, with no significant differences between groups (ANOVA P=0.08, 0.62, respectively). CONCLUSIONS: The novel cyanoacrylate compound examined in this study is a highly effective suture line sealant with only mild tissue reactivity and no significant effects on graft patency when studied over an 18 month period.

Anastomosis, Surgical↗
PubMed2005

Adenosine A2A receptor agonist improves cardiac dysfunction from pulmonary ischemia-reperfusion injury.

BACKGROUND: Ischemia-reperfusion (IR) injury negatively impacts patient outcome in lung transplantation. Clinically, we observed that lung transplant patients with ischemia-reperfusion injury tend to have cardiac dysfunction. Previous studies have shown that ATL-146e (4-{3-[6-amino-9-(5-ethylcarbamoyl-3,4-dihydroxy-tetrahydro-furan-2-yl)-9H-purin-2-yl]-prop-2-ynyl}-cyclohexanecarboxylic acid methyl ester), a selective adenosine A2A receptor agonist, reduces lung inflammation after ischemia-reperfusion. We hypothesized that pulmonary ischemia-reperfusion causes secondary heart dysfunction and ATL-146e will improve this dysfunction. METHODS: We utilized an in vivo rabbit lung ischemia-reperfusion model. The Sham group underwent 120 minutes single lung ventilation. The IR and ATL groups underwent 90 minutes right lung ischemia with 30 minutes right lung reperfusion. The ATL-146e was given intravenously to the ATL group during reperfusion. Cardiac output and arterial blood gases were monitored, and neutrophil sequestration was measured by myeloperoxidase activity. RESULTS: Upon reperfusion, cardiac output (mL/min) significantly dropped in the IR and ATL groups. By 15 minutes reperfusion, cardiac output in the ATL group improved significantly over the IR group and remained significant thereafter. Lung myeloperoxidase activity was significantly reduced by ATL-146e. Although never hypoxemic, arterial oxygenation was lower in the IR and ATL groups while central venous pressures and mean arterial pressures were similar among groups. A separate experiment demonstrated that reperfusion with the antioxidant N-(2-mercaptopropionyl)glycine prevented cardiac dysfunction. CONCLUSIONS: Pulmonary ischemia-reperfusion causes cardiac dysfunction independent of preload, afterload, and oxygenation. The ATL-146e improves this dysfunction presumably by the antiinflammatory effects of adenosine A2A receptor activation on neutrophils. One likely mechanism involves the release of oxidants from the ischemic lung upon reperfusion, which has immediate negative effects on the heart.

Adenosine A2 Receptor Agonists↗
PubMed2005

Acute sleep deprivation in the thoracic surgical resident does not affect operative outcomes.

BACKGROUND: There is an increasing trend toward work hour restrictions for doctors world wide. These reforms have been inspired, in part, by the assertion by some that the fatigued physician is more prone to making errors. Interestingly, there is very little in the way of objective data with regard to the effects of sleep deprivation on patient outcomes. We have recently studied this in attending surgeons. The present study focused on thoracic surgical residents. Our hypothesis was that acute sleep deprivation would not lead to an increase in operative times or complications. METHODS: A retrospective review of all cases performed by thoracic surgical residents at the University of Virginia from January 1994 to March of 2004 was done. Complication rates of cases performed by "sleep deprived" (SD) residents were compared with cases done when the residents were "not sleep deprived" (NSD). A resident was deemed sleep deprived if he or she performed a case the previous evening that started between 10 pm and 5 am or ended between the hours of 11 pm and 7:30 am. RESULTS: A total of 7,323 cases were recorded in the STS database over the 10-year period examined. Two hundred and twenty-nine of these cases (3%) were performed by SD residents. Mortality rates for coronary artery bypass operations showed no significant differences (2.1% [SD = 3 of 141 patients] vs 3.1% (NSD = 143 of 4452 patients), p = 0.63). A comparison of operative, neurologic, renal, infectious, and pulmonary complications as well as cardiopulmonary bypass times, cross-clamp times, the use of blood products, and length of stay also demonstrated no significant differences between groups. CONCLUSIONS: Acute sleep deprivation in thoracic surgical residents does not affect operative efficiency, morbidity, or mortality in cardiac surgical operations.

Cardiac Surgical Procedures↗
PubMed2005

Adenosine A2A receptor activation reduces inflammation and preserves pulmonary function in an in vivo model of lung transplantation.

BACKGROUND: Reperfusion injury continues to significantly affect patients undergoing lung transplantation. Isolated lung models have demonstrated that adenosine A 2A receptor activation preserves function while decreasing inflammation. We hypothesized that adenosine A 2A receptor activation by ATL-146e during the initial reperfusion period preserves pulmonary function and attenuates inflammation in a porcine model of lung transplantation. METHODS: Mature pig lungs preserved with Viaspan (Barr Laboratories, Pomona, NY) underwent 6 hours of cold ischemia before transplantation and 4 hours of reperfusion. Animals were treated with (ATL group, n = 7) and without (IR group, n = 7) ATL-146e (0.05 microg kg -1 . min -1 ATL-146e administered intravenously for 3 hours). With occlusion of the opposite pulmonary artery, the animal was maintained for the final 30 minutes on the allograft alone. Recipient lung physiology was monitored before tissue evaluation of pulmonary edema (wet-to-dry weight ratio), myeloperoxidase assay, and tissue tumor necrosis factor alpha by means of enzyme-linked immunosorbent assay. RESULTS: When the ATL group was compared with the IR group, the ATL group had better partial pressure of carbon dioxide (43.8 +/- 4.1 vs 68.9 +/- 6.3 mm Hg, P < .01) and partial pressure of oxygen (272.3 +/- 132.7 vs 100.1 +/- 21.4 mm Hg, P < .01). ATL-146e-treated animals exhibited lower pulmonary artery pressures (33.6 +/- 2.1 vs 47.9 +/- 3.5 mm Hg, P < .01) and mean airway pressures (16.25 +/- 0.08 vs 16.64 +/- 0.15 mm Hg, P = .04). ATL-146e-treated lungs had lower wet-to-dry ratios (5.9 +/- 0.39 vs 7.3 +/- 0.38, P < .02), lower myeloperoxidase levels (2.9 x 10 -5 +/- 1.2 x 10 -5 vs 1.3 x 10 -4 +/- 4.0 x 10 -5 DeltaOD mg -1 . min -1 , P = .03), and a trend toward decreased lung tumor necrosis factor alpha levels (57 +/- 12 vs 96 +/- 15 pg/mL, P = .06). The ATL group demonstrated significantly less inflammation on histology. CONCLUSION: Adenosine A 2A activation during early reperfusion attenuated lung inflammation and preserved pulmonary function in this model of lung transplantation. ATL-146e and similar compounds could play a significant role in improving outcomes of pulmonary transplantation.

Adenosine A2 Receptor Agonists↗
PubMed2005

Hyperoxic ventilation exacerbates lung reperfusion injury.

OBJECTIVE: It is well known that hyperoxia can be potentially harmful to the ventilated patient, although little is known about the potential effects in the setting of lung reperfusion. We hypothesized that hyperoxic ventilation at the time of reperfusion could worsen the effects of lung reperfusion injury. METHODS: Using an ex vivo, blood perfused, isolated rabbit lung system, we evaluated the effects of hyperoxic (fraction of inspired oxygen = 100%, n = 10) versus normoxic (room air, n = 10) ventilation after 18 hours of cold ischemia. Lungs were ventilated and perfused for 2 hours. A control group was immediately perfused and ventilated with a fraction of inspired oxygen of 100%. RESULTS: Lung wet/dry ratios demonstrated lower tissue edema in the normoxic group compared with in the hyperoxic group (6.72 +/- 0.89 vs 7.62 +/- 1.14 [mean +/- standard error of the mean], P = .04). Lung ventilation was also significantly better in the normoxic group versus the hyperoxic group (PCO2 = 28.96 +/- 2.01 vs 36.68 +/- 3.20 mm Hg, P = .04). Conversely, lung oxygenation after 2 hours of reperfusion (normoxic group ventilated for the last 15 minutes on 100% fraction of inspired oxygen) was not significantly different between groups (PO2 = 590.2 +/- 50.1 vs 499.6 +/- 67.5 mm Hg, P = .25). CONCLUSIONS: Ventilating lungs with 100% fraction of inspired oxygen at the time of reperfusion could increase the risk of lung reperfusion injury at the time of transplantation. Thus the patient should be ventilated with as low a fraction of inspired oxygen as possible to achieve adequate oxygen saturations during this critical reperfusion period.

Animals↗
PubMed2005

Acute descending aortic dissections: management of visceral, spinal cord, and extremity malperfusion.

Acute descending aortic dissection is considered the most catastrophic event affecting the aorta and occurs two to three times more often than rupture of abdominal aortic aneurysms. The therapeutic aim in treating acute dissection is not only directed at the prevention of aneurysmal development and rupture but also to prevent and treat complications such as malperfusion syndrome. According to Lauterbach and coworkers patients with symptomatic malperfusion syndromes have a 51% mortality rate compared with a 29% mortality rate in patients who do not. The surgical in-hospital mortality rate in patients with mesenteric or peripheral vascular ischemic complications may be as high as 89%. Despite an improvement in diagnosing dissections and malperfusion syndromes, and despite improved operative techniques and a better understanding of the significance of perioperative care, the surgical mortality rate can be as high as 50%. Endovascular techniques are constantly evolving that provide an alternative to open procedures. The goal of this article was to review the pathogenesis of malperfusion syndromes in aortic dissection, discuss the current modalities to treat malperfusion of the spinal cord, viscera, and extremities, and examine the results of the treatments used today.

Acute Disease↗
PubMed2005

Subintimal arterial flossing with antegrade-retrograde intervention (SAFARI) for subintimal recanalization to treat chronic critical limb ischemia.

PURPOSE: To describe the technique of subintimal arterial flossing with antegrade-retrograde intervention (SAFARI) to improve technical success for the performance of subintimal recanalization when there is failure to reenter the distal true lumen or when there is a limited segment of patent distal target artery available for reentry. MATERIALS AND METHODS: Subintimal recanalization was attempted in an antegrade direction in all patients. If reentry into the distal true lumen was unsuccessful or a short segment of target artery was present, retrograde access was obtained in the distal target artery (popliteal, anterior tibial/dorsalis pedis, or posterior tibial) and a retrograde subintimal channel was created. A guide wire was used to connect the retrograde and antegrade subintimal channels simultaneously to create a "flossing" guide wire. The subintimal tract was dilated with balloon angioplasty with or without stent implantation. Limb salvage, amputation-free survival, and survival rates over time were determined. RESULTS: The SAFARI technique resulted in successful subintimal recanalization creating straight-line flow to the foot in all 21 limbs in 20 patients in which the technique was attempted. Antegrade-retrograde access was performed with the femoral artery and the following vessels: popliteal, n = 11; anterior tibial/dorsalis pedis, n = 10; and posterior tibial, n = 2 (two limbs involved multiple accesses). All procedures were successful. The limb salvage rate with SAFARI was 90% (95% CI, 74%-100%) at 6 months. CONCLUSIONS: The SAFARI technique can be useful for completing subintimal recanalization when there is failure to reenter the distal true lumen from an antegrade approach or when there is limited distal target artery available for reentry. The SAFARI technique improves technical success in the performance of subintimal recanalization. Limb salvage rates are comparable to those with antegrade subintimal recanalization.

Aged↗
PubMed2005

Subfascial endoscopic perforating vein surgery (SEPS) for the treatment of venous ulcers.

Lower extremity ulcerations that result from venous hypertension are a significant cause of disability in Western nations. Venous ulcers, highly related to lower extremity venous valvular incompetence and post-thrombotic syndrome, demonstrate a protracted course of healing with a high recurrence rate when managed conservatively. Effective treatment includes correcting the elevated lower extremity venous pressure using non-invasive (compression therapy) or invasive modalities (removal or correction of incompetent venous segments, most commonly the greater saphenous vein). Minimally invasive subfascial endoscopic perforating vein surgery, performed on an outpatient basis, allows ligation of incompetent Cockett perforating veins. Venous ulcer healing rates of 88% and infrequent wound complications have been reported using this technique. Using 5-mm cameras and trocars that are available for other endoscopic surgeries could further improve this technique; creating ports smaller than the traditional 15-mm incisions would subsequently reduce tissue disruption. In addition, the etiology of recurrent ulceration and the failure of the primary ulcer to heal are not completely understood. If these poor outcomes can be further defined, even higher rates of wound healing may be attained using this procedure. Significant efforts have been devoted to elucidating the exact mechanism of skin breakdown from venous hypertension but the pathophysiology of this process is still not understood.

Endoscopy↗
PubMed2004

Magnetic resonance imaging identifies the fibrous cap in atherosclerotic abdominal aortic aneurysm.

BACKGROUND: MRI can distinguish components of atherosclerotic plaque. We hypothesized that contrast enhancement with gadolinium-DTPA (Gd-DTPA) could aid in the differentiation of plaque components in abdominal aortic aneurysm (AAA). METHODS AND RESULTS: Twenty-three patients (19 males, age 70+/-8 years) with AAA underwent MRI on a 1.5-T clinical scanner 3+/-3 days before surgical grafting. T1- and T2-weighted (W) black blood spin echo imaging was performed in 1 axial slice, and the T1-W imaging was repeated after a Gd-DTPA-enhanced 3D magnetic resonance angiogram. A section of the aorta at the site of imaging was resected at surgery for histopathologic examination of tissue components and inflammatory cells. Signal-to-noise and contrast-to-noise ratios (CNR) were measured in visualized plaque components from multispectral MRI, and percent enhancement after contrast on T1-W imaging was calculated. The kappa value for agreement between pathology and MRI for the number of tissue components was 0.785. T2-W imaging identified thrombus as regions of high signal and lipid core as low signal, with a CNR of 6.43+/-3.41. Nine patients had a fibrous cap pathologically, which was visualized as a discrete area of uniform increased signal on T2-W imaging with a CNR of 4.52+/-1.93 compared with lipid core. Within the cap, the percent enhancement after Gd-DTPA on T1-W imaging was 91+/-63%. CONCLUSIONS: Higher signal on T2-W MRI identifies the fibrous cap and thrombus within AAA. Contrast enhancement improves delineation of the fibrous cap. The addition of contrast to MRI plaque imaging may enhance identification of vulnerable plaque.

Aged↗