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Biomedical subjects

M D Dake

Publications and source records attributed to M D Dake.

At least 19 recordsLinked to original sources
PubMed2001

Effect of human recombinant vascular endothelial growth factor165 on progression of atherosclerotic plaque.

OBJECTIVES: This study was designed to evaluate the impact of recombinant human vascular endothelial growth factor165 (rhVEGF) on atherosclerotic plaque progression. BACKGROUND: Therapeutic angiogenesis represents a promising treatment for ischemic diseases. However, angiogenesis may impact atherosclerosis. METHODS: Albumin or rhVEGF was administered by a single intramuscular injection (2 microg/kg body weight) to New Zealand White rabbits fed with a 0.25% cholesterol diet beginning three weeks before therapy. Subsets of rabbits from each group underwent perfusion-fixation and harvesting of the thoracic aorta for morphometric and immunohistochemical analyses at 7 or 21 days. RESULTS: The mean plaque area was 15.75+/-2.28% and 22.00+/-3.24% with VEGF and 0.67+/-0.22% and 1.17+/-0.34% with albumin at 7 and 21 days, respectively. The plaque circumference was 13.00+/-2.58% and 23.75+/-2.86% with VEGF and 2.50+/-0.65% and 6.25+/-1.88% with albumin at 7 and 21 days, respectively. The maximal plaque thickness was 0.11+/-0.002 and 0.15+/-0.007 mm with VEGF and 0.04+/-0.009 and 0.07+/-0.003 mm with albumin at 7 and 21 days, respectively. The endothelial density (reported as percent total plaque area) was 31.75+/-4.42% and 63.00+/-8.45% with VEGF and 7.75+/-1.65% and 12.75+/-1.93% with albumin at 7 and 21 days, respectively. The macrophage density was 4.5+/-0.86 and 19.25+/-1.54 with VEGF and 4.26+/-0.75 and 6.00+/-1.08 with albumin at 7 and 21 days, respectively. CONCLUSIONS: Recombinant human VEGF increases the rate and degree of atherosclerotic plaque formation in the thoracic aorta in a cholesterol-fed rabbit model.

Animals↗
PubMed2001

High-efficiency endovascular gene delivery via therapeutic ultrasound.

OBJECTIVES: We studied enhancement of local gene delivery to the arterial wall by using an endovascular catheter ultrasound (US). BACKGROUND: Ultrasound exposure is standard for enhancement of in vitro gene delivery. We postulate that in vivo endovascular applications can be safely developed. METHODS: We used a rabbit model of arterial mechanical overdilation injury. After arterial overdilation, US catheters were introduced in bilateral rabbit femoral arteries and perfused with plasmidor adenovirus-expressing blue fluorescent protein (BFP) or phosphate buffered saline. One side received endovascular US (2 MHz, 50 W/cm2, 16 min), and the contralateral artery did not. RESULTS: Relative to controls, US exposure enhanced BFP expression measured via fluorescence 12-fold for plasmid (1,502.1+/-927.3 vs. 18,053.9+/-11,612 microm2, p < 0.05) and 19-fold for adenovirus (877.1+/-577.7 vs. 17,213.15+/-3,892 microm2, p < 0.05) while increasing cell death for the adenovirus group only (26+/-5.78% vs. 13+/-2.55%, p < 0.012). CONCLUSIONS: Endovascular US enhanced vascular gene delivery and increased the efficiency of nonviral platforms to levels previously attained only by adenoviral strategies.

Angioscopy↗
PubMed2001

Endovascular stent-graft management of thoracic aortic diseases.

The traditional standard therapy for descending thoracic aortic aneurysm (TAA) is open operative repair with graft replacement of the diseased aortic segment. Despite important advances in surgical techniques, anesthetic management, and post-operative care over the last 30 years, the mortality and morbidity of surgery remains considerable, especially in patients at high risk for thoracotomy because of coexisting severe cardiopulmonary abnormalities or other medical diseases. The advent of endovascular stent-graft technology provides an alternative to open surgery for selected patients with TAA. The initial experience suggests that stent-graft therapy potentially may reduce the operative risk, hospital stay and procedural expenses of TAA repair. These potential benefits are especially attractive for patients at high risk for open TAA repair. Current results of endovascular TAA therapy document operative mortalities of between 0 and 4%, aneurysm thrombosis in 90 and 100% of cases, and paraplegia as a complication in 0 and 1.6% of patients. The early success of stent-graft repair of TAA has fostered the application of these devices for the management of a wide variety of thoracic aortic pathologies, including acute and chronic dissection, intramural hematoma, penetrating ulcer, traumatic injuries, and other diseases. The results of prospective controlled trials that compare the outcomes of stent-graft therapy with those of surgical treatment in patients with specific types of aortic disease are anxiously awaited before recommendations regarding the general use of these new devices can be made with confidence.

Aortic Aneurysm, Thoracic↗
PubMed2001

Isolated lower extremity chemotherapeutic infusion for treatment of osteosarcoma: experimental study and preliminary clinical report.

PURPOSE: To increase the dose of drug delivered to a tumor while maintaining tolerable systemic side effects, an interventional technique of isolated lower extremity infusion was investigated. MATERIALS AND METHODS: Experiments were performed in eight dogs. Four dogs were treated by a combination of intraarterial (IA) femoral cisplatin infusion at a dose of 2.0 mg/kg with drug removal from the ipsilateral extremity venous blood by a dialyzer. The other four dogs comprised the control group. In these animals, left femoral arterial IA cisplatin infusion was performed without dialysis. Leukocyte and platelet counts, blood urea nitrogen (BUN) levels, and serum creatinine levels were recorded before and after the treatment. Subsequently, two human patients with inoperable osteosarcoma were treated with the isolated infusion. RESULTS: In the experiments, 85%-90% of the free platinum that entered the dialyzer was removed. The peak systemic plasma cisplatin concentrations in animals undergoing dialysis were reduced by 81.25% compared to those in animals undergoing femoral IA infusion without hemodialysis. There were no significant changes in the hematologic profiles or BUN and serum creatinine levels in the experimental animals. However, in the control group, all dogs developed myelosuppression and severe renal toxicity after IA infusion of the same dose of cisplatin. Clinically, immediate relief of symptoms related to the primary tumor was achieved in both human patients after the combination of isolated IA infusion and embolotherapy. CONCLUSION: Single-pass hemodialysis removed a significant amount of cisplatin after regional IA infusion, reduced systemic toxicity, and permitted survival of the experimental animals. In two patients with osteosarcoma, percutaneous isolated lower extremity chemotherapeutic infusion therapy and embolotherapy were performed safely with partial responses.

Adolescent↗
PubMed2001

Portal-systemic myelopathy after transjugular intrahepatic portosystemic shunt creation: report of four cases.

The authors attempted to describe the clinical manifestations of portal-systemic myelopathy (PSM) after transjugular intrahepatic portosystemic shunt (TIPS) creation. PSM was developed in four of 212 (1.89%) patients who underwent TIPS procedures in our hospital. Three men and one woman, ranging in age from 41 to 56 years, with a history of posthepatitis cirrhosis and recurrent bleeding from gastroesophageal varices had intrahepatic shunts created with 10-mm-diameter Wallstents. Shunt patency was confirmed by color Doppler ultrasonography (US) in each patient after TIPS creation. Progressive spastic paraparesis involving the lower extremities occurred between 5 weeks and 5 months after TIPS creation in the four patients. Neurologic examination showed evidence of spasticity in all cases, with ankle clonus, extensor plantar responses, and lower extremity hyperreflexia. All sensory modalities remained intact. Cytologic examination of cerebrospinal fluid from each patient was normal. There was no evidence of spinal cord compression on the imaging studies. PSM is a rare syndrome that includes spastic paraparesis with intact sensation. Initially noted in patients who have undergone surgical placement of a portacaval shunt, it also may occur after TIPS creation.

Adult↗
PubMed2001

Therapeutic elastase inhibition by alpha-1-antitrypsin gene transfer limits neointima formation in normal rabbits.

PURPOSE: Alpha-1-antitrypsin (AAT) is the major circulating elastase inhibitor. Deficiency of elastase inhibition leads to emphysema and vascular abnormalities including accelerated neointima. Because recent evidence suggests that tissue AAT levels determine inhibitory function, the authors hypothesize that local tissue-based expression of AAT limits elastase activity sufficiently to guide arterial response to injury. MATERIALS AND METHODS: Rabbit common femoral arteries were injured by mechanical overdilation and treated with buffer, viral control, or an adenovirus expressing AAT (Ad/AAT). After 3 and 28 days, intima-to-media (I/M) ratios were evaluated. Additionally, early changes in elastase inhibition potential (3 d), extracellular elastin and collagen content (3 d), and local macrophage and neutrophil infiltration (7 d) were determined. RESULTS: Ad/AAT significantly decreased neointima formation after mechanical dilation injury after 28 days: buffer controls exhibited mean I/M ratios of 0.76 +/- 0.06, whereas viral controls reached 0.77 +/- 0.09; in contrast, Ad/AAT reduced I/M ratios to 0.44 +/- 0.06. Both early elastin and collagen content were preserved in the Ad/AAT group relative to controls. The Ad/AAT group also reversed the local inflammation that characterized viral controls. CONCLUSIONS: This strategy demonstrates that local increases in elastase inhibition potential promote a neointima-resistant small-caliber artery, which may offer new promise in management of patients undergoing angioplasty.

Angioplasty↗
PubMed2001

Delayed complications after esophageal stent placement for treatment of malignant esophageal obstructions and esophagorespiratory fistulas.

PURPOSE: To evaluate delayed complications after esophageal expandable metallic stent placement. MATERIALS AND METHODS: From April 1993 to December 1997, 90 expandable metallic stents were placed in 82 consecutive patients with inoperable malignant esophageal obstruction (n = 49) or malignant esophagorespiratory fistula (n = 33). Stents used included covered Gianturco-Rosch Z stents (n = 20), Wallstents (covered, n = 31; uncovered, n = 13), and Ultraflex stents (covered, n = 8; uncovered, n = 10). Patients were followed prospectively and monitored for delayed complications, defined as major (hemorrhage, tracheal compression, stent migration, perforation or fistula formation, granulomatous obstruction, tumor ingrowth and overgrowth, funnel phenomenon, and stent covering disruption) or minor (reflux, chest pain, and food impaction). RESULTS: Mean survival was 4.5 months after stent placement (range, 3 weeks to 26 months). The overall incidence of delayed complications was 64.6%, with 17 patients (20.7%) experiencing more than one complication. The rates of delayed complications in patients with Z stents, Wallstents, and Ultraflex stents were 75.0%, 68.1%, and 44.4%, respectively (P <.05). Most complications were life-threatening and occurred more frequently when stents were placed in the proximal third of the esophagus, compared with more distally (P <.05). Thirteen patients (15.9%) died from complications directly related to stent placement. CONCLUSION: Esophageal stent placement for malignant obstruction or fistula is associated with a substantial incidence of delayed complications.

Aged↗
PubMed2001

Perivascular release of insulin-like growth factor-1 limits neointima formation in the balloon-injured artery by redirecting smooth muscle cell migration.

PURPOSE: Insulin-like growth factor-1 (IGF-1) is a potent chemoattractant to vascular smooth muscle cells (SMCs). The authors hypothesize that perivascular release of IGF-1 in vivo can direct migration of SMCs away from the lumen and reduce neointima formation in a rabbit model of arterial balloon injury. MATERIALS AND METHODS: Balloon angioplasty of the common femoral arteries was performed in adult male New Zealand White rabbits (n = 8 per treatment group) and controlled release microspheres delivering either IGF-1 or blank control treatment were implanted perivascularly at the angioplasty site prior to surgical closure. At 7 days, five arteries per group were harvested and cross-sections were subjected to anti-PCNA (proliferating cell nuclear antigen) immunostaining to determine the number and distribution of proliferating SMCs. At 28 days, the remaining three arteries per group were harvested and sections were evaluated for intima-to-media (I/M) ratios by means of VVG-Masson staining. One-way analysis of variance with Fisher protected least significant difference post hoc testing was used to determine statistical significance at P < .05. RESULTS: At 7 days, PCNA(+) medial SMCs assumed a significantly more peripheral (ie, further from lumen) distribution in the vessel wall with use of perivascular IGF-1 than with use of blank treatment (P < .05). Overall SMC proliferation was not significantly different, thus the change in distribution was likely due to directionally altered SMC migration. At 28 days, perivascular IGF-1 significantly decreased I/M ratios by 44% relative to control treatment (P < .05). CONCLUSIONS: Perivascular release of IGF-1 can directionally guide SMC migration away from the lumen and reduce neointima in the balloon-injured artery. This novel strategy might have implications in the development of antirestenosis therapies.

Angioplasty, Balloon↗
PubMed2001

Vascular endothelial growth factor enhances atherosclerotic plaque progression.

Vascular endothelial growth factor (VEGF) can promote angiogenesis but may also exert certain effects to alter the rate of atherosclerotic plaque development. To evaluate this potential impact on plaque progression, we treated cholesterol-fed mice doubly deficient in apolipoprotein E/apolipoprotein B100 with low doses of VEGF (2 microg/kg) or albumin. VEGF significantly increased macrophage levels in bone marrow and peripheral blood and increased plaque area 5-, 14- and 4-fold compared with controls at weeks 1, 2 and 3, respectively. Plaque macrophage and endothelial cell content also increased disproportionately over controls. In order to confirm that the VEGF-mediated plaque progression was not species-specific, the experiment was repeated in cholesterol-fed rabbits at the three-week timepoint, which showed comparable increases in plaque progression.

Animals↗
PubMed2001

Update on the bifurcated EXCLUDER endoprosthesis: phase I results.

Many devices are being investigated for treatment of infrarenal abdominal aortic aneurysms. This report describes the particular characteristics of a next generation modular endograft and the Phase I results in 29 patients. Larger comparative studies are in progress to assess the safety and efficacy of this new design.

Aged↗
PubMed2001

Enhancement of neointima formation with tissue-type plasminogen activator.

PURPOSE: Indirect evidence suggests that tissue plasminogen activator (tPA) either limits or does not alter restenosis. However, tPA enhances tumor invasiveness through matrix remodeling, and several elements of degraded matrix enhance smooth muscle cell mitogenesis. We use either local adenoviral-mediated overexpression of tPA or systemic infusion of recombinant tPA combined with mechanical overdilation of rabbit common femoral arteries to evaluate the impact of tPA on neointima formation. METHODS: Left common femoral arteries of New Zealand white rabbits were transfected in situ either with an adenoviral-construct-expressing tPA or a viral control (adenoviral-construct-expressing beta-galactosidase) or nonviral (buffer) control after balloon angioplasty injury. At 7 and 28 days, left common femoral artery segments were harvested (n = 4 for each group and time point). Vessel segments were examined for intimato-media ratio, smooth muscle cell proliferation, extracellular matrix, and inflammatory response. Thrombus formation was evaluated after 3 days (n = 3 for each group). In a second experiment, New Zealand white rabbits (n = 3 per group, per time point) underwent mechanical dilation followed by buffer treatment or systemic tPA infusion according to a widely clinically used accelerated infusion protocol. Treated artery segments were harvested after 7 or 28 days and processed for intima-to-media ratio determination and class-wide histochemical determination of collagenous extracellular matrix and collagen content. RESULTS: Both rate and degree of neointima formation increase dramatically with overexpression (250%-461% relative to controls at 7 and 28 days). Substantial early matrix degradation is observed in vessels treated with local overexpression of tPA, although no increases in local inflammation or in smooth muscle proliferation occur. Late enhancement of smooth muscle proliferation emerges, consistent with secondary impact of perturbed matrix components. Systemic infusion of tPA according to clinical protocols also results in early and late enhancement of neointima formation in this model (34%-52% relative to controls at at 7 and 28 days), with significant early collagenous matrix degradation. Systemic infusion, although significant, did not attain the degree of neointima formation present with overexpression. CONCLUSION: With some evidence of dose-dependence, tissue plasminogen activator enhances neointima formation after angioplasty in a rabbit model. Early matrix degradation precedes change in rates of proliferation and underlies this effect in spite of several antirestenotic actions including decreased thrombus and decreased macrophage recruitment in this model.

Adenoviridae↗
PubMed2000

Thrombomodulin overexpression to limit neointima formation.

BACKGROUND-These studies were initiated to confirm that high-level thrombomodulin overexpression is sufficient to limit neointima formation after mechanical overdilation injury. METHODS AND RESULTS-An adenoviral construct expressing thrombomodulin (Adv/RSV-THM) was created and functionally characterized in vitro and in vivo. The impact of local overexpression of thrombomodulin on neointima formation 28 days after mechanical overdilation injury was evaluated. New Zealand White rabbit common femoral arteries were treated with buffer, viral control, or Adv/RSV-THM and subjected to mechanical overdilation injury. The treated vessels (n=4 per treatment) were harvested after 28 days and evaluated to determine intima-to-media (I/M) ratios. Additional experiments were performed to determine early (7-day) changes in extracellular elastin and collagen content; local macrophage, T-cell, and neutrophil infiltration; and local thrombus formation as potential contributors to the observed impact on 28-day neointima formation. The construct significantly decreased neointima formation after mechanical dilation injury in this model. By histological analysis, buffer controls exhibited mean I/M ratios of 0.76+/-0.06%, whereas viral controls reached 0.77+/-0.08%; in contrast, Adv/RSV-THM reduced I/M ratios to 0.47+/-0.06%. Local inflammatory infiltrate decreased in the Adv/RSV-THM group relative to controls, whereas matrix remained relatively preserved. Rates of early thrombus formation also decreased in Adv/RSV-THM animals. CONCLUSIONS-This construct thus offers a viable technique for promoting a locally neointima-resistant small-caliber artery via decreased thrombus bulk, normal matrix preservation, and decreased local inflammation without the inflammatory damage that has limited many other adenoviral applications.

Animals↗
PubMed2000

Internal iliac artery embolization in the stent-graft treatment of aortoiliac aneurysms: analysis of outcomes and complications.

PURPOSE: To analyze the complications of internal iliac artery (IIA) embolization in conjunction with stent-graft treatment of aortoiliac aneurysms. MATERIALS AND METHODS: Seventy-one patients with aortoiliac (n = 47) or iliac (n = 24) aneurysms were treated with endoluminal placement of stent-grafts. Thirty-two patients (31 men, one woman; mean age, 73 years; range, 56-88 years) had embolization or occlusion of one (n = 27) or both (n = 5) IIAs. Status of the IIAs and the collateral circulation was assessed by retrospective review of angiographic images. Follow-up consisted of a standardized patient questionnaire and review of radiologic and medical records. RESULTS: The mean follow-up time was 35 months (range, 5-64 months). Eleven of the 47 patients with abdominal aortic aneurysms (AAA) (23%) and 19 of the 24 patients with iliac aneurysms (79%) required IIA embolization. One patient with AAA and another with iliac aneurysm had unintentional occlusion of an IIA by extension of the stent-graft over their origins. A total of seven patients had bilateral occlusion of the IIAs after the procedure. Additionally, the inferior mesenteric arteries (IMAs) of two other patients with AAA were also embolized. In six patients, all three vessels were occluded after placement of the stent-grafts. Symptoms were reported in nine of the 20 (45%) patients with iliac aneurysms and in three of the 12 (25%) patients with AAA. Symptoms consisted of buttock claudication (nine of 32, 28%), new sexual dysfunction (two of 16, 12%), and transient urinary retention (3%). Seven of the claudicants had resolution of symptoms after a mean interval of 14 months (range, 1-36 months). There were no instances of bowel ischemia, neurologic sequelae, or buttock necrosis related to these procedures. CONCLUSION: Embolization of the IIA is associated with symptoms in a significant number of patients. While symptoms are transient in most patients, they can be problematic. Efforts should be made to preserve the pelvic circulation if possible.

Aged↗
PubMed2000

Stent-graft therapy for subclavian artery aneurysms and fistulas: single-center mid-term results.

PURPOSE: To evaluate the potential of covered stents to replace surgery in the treatment of subclavian artery aneurysms and traumatic injuries. MATERIALS AND METHODS: Nine patients (five men, four women; age range, 20-83 years; mean, 54 years) with subclavian artery aneurysms (n = 5) or fistulas (n = 4) were treated with stent-grafts. All devices used were custom-made, consisting of polytetrafluoroethylene (PTFE)-covered Palmaz (n = 5), Wallstent (n = 2), Z stents (n = 8), or a polyester-covered Z stent (n = 1). One patient was lost to follow-up after 2 months. All others were followed up with clinical evaluation, computed tomography (CT), and/or ultrasound. RESULTS: All devices were deployed successfully with exclusion of the aneurysms and fistulas. There were two procedure-related complications (22%), consisting of groin pseudoaneurysms requiring surgical repair 3 and 9 days after the procedure. One of those patients required additional oral antibiotic therapy for a postsurgical groin wound infection. One patient developed a stenosis at 12 months, which required angioplasty. The stent-graft thrombosed in one patient because of a kink 2 months after placement, which was successfully treated by thrombolysis and placement of a Wallstent. The primary and secondary patencies are 89% and 100%, respectively, after a mean follow-up of 29 months (2-66 mo). CONCLUSION: Mid-term results of stent-graft therapy of subclavian artery aneurysms and fistulas are encouraging, with low morbidity and excellent clinical outcome.

Adult↗
PubMed2000

True-lumen collapse in aortic dissection: part I. Evaluation of causative factors in phantoms with pulsatile flow.

PURPOSE: To investigate the causative factors in true-lumen collapse in a model of aortic dissection. MATERIALS AND METHODS: Phantoms with an aortic arch, true and false lumina with abdominal branch vessels, and a distal bifurcation were used to model a Stanford type B aortic dissection. The effects of anatomic factors (entry-tear size, branch-vessel flow distribution, fenestrations, distal reentry communication) and physiologic factors (peripheral resistance in the branch vessels, pump output and rate, vascular compliance) on true-lumen collapse were investigated. The morphology of the true lumen was observed. Branch pressures and flow rates were measured. RESULTS: True-lumen collapse was induced and was exacerbated by an increase in the size of the entry tear, a decrease in the false-lumen outflow caused by occluding the false-lumen branch vessels, and an increase in the true-lumen outflow caused by lowering the peripheral resistance in true-lumen branch vessels. Two kinds of true-lumen collapse depended on pump output. With low pump output and low outflow resistance from the true lumen, the true lumen collapsed. With high pump output and low inflow resistance in the false lumen, the true lumen was compressed. Distal reentry communication between the true and false limbs was more effective than aortic fenestrations in preventing true-lumen collapse. CONCLUSION: True-lumen collapse in this dissection model strongly depends on the difference in the ratios of inflow capacity to outflow capacity in the true and false lumina. Both anatomic and physiologic factors can affect true-lumen collapse.

Aortic Dissection↗
PubMed2000

Chronically occluded inferior venae cavae: endovascular treatment.

PURPOSE: To report the results of endoluminal recanalization and stent placement in patients with chronic occlusions of the inferior vena cava (IVC). MATERIALS AND METHODS: Seventeen consecutive patients (12 male, five female patients; mean age, 40.6 years; age range, 15-77 years) with chronic IVC occlusions were treated during a 6-year period. The mean duration of symptoms was 32 months. Underlying active malignancy was the cause of occlusion in four patients. Five patients with superimposed acute thrombus underwent catheter-directed thrombolysis prior to IVC recanalization. Clinical patency was defined as absence or improvement of symptoms. Clinical follow-up was supplemented with ultrasonography, vena cavography, or both in 10 patients. RESULTS: Technical success was achieved in 15 (88%) patients. Additional thrombolytic therapy and stent placement was needed in two patients to maintain patency at 4 and 6 months after the procedure. Twelve patients had IVCs that remained patent after a mean follow-up of 19 months for a primary patency rate of 80%. The primary assisted patency rate was 87% (13 of 15). There were four deaths owing to underlying disease 6-21 months after the procedures. There were no procedure-related complications. CONCLUSION: Endoluminal recanalization and stent placement in chronically occluded IVCs has a good intermediate-term outcome and should be considered in patients who have symptoms and who often do not have adequate alternative therapy.

Adolescent↗
PubMed2000

True-lumen collapse in aortic dissection: part II. Evaluation of treatment methods in phantoms with pulsatile flow.

PURPOSE: To discover and evaluate the effective treatment methods to prevent or relieve true-lumen collapse in models of aortic dissection. MATERIALS AND METHODS: Two phantoms were built to simulate type B aortic dissection. After true-lumen collapse was induced, experiments were conducted to evaluate the effectiveness of clinically relevant variables in relieving the collapse. Variables included entry-tear size, branch-vessel flow distribution, distal reentry communication between the true and false limbs, aortic fenestrations, and pump output. To test the effect of closing the entry tear, a stent-graft was deployed over the entry tear under physiologic conditions in a mock-flow loop. The difference in the effect of each variable on the prevention and relief of true-lumen collapse was also investigated. RESULTS: It was more difficult to relieve true-lumen collapse than it was to prevent it. Placement of a stent-graft over the entry tear was the most effective method of relieving true-lumen collapse. Less-effective procedures included opening a false-lumen outflow branch and opening the distal reentry branch. Opening the fenestration-branch loops, meant to simulate the creation of artificial fenestrations in the intimal flap, did not relieve true-lumen collapse. CONCLUSION: The definitive treatment for true-lumen collapse in aortic dissection is direct repair of the entry tear to decrease false-lumen inflow. Otherwise, increasing the false-lumen outflow and/or creating distal fenestrations between the true and false lumina distal to the level of the compromised aortic branch are less-effective alternatives.

Aortic Dissection↗