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Biomedical subjects

M D Dake

Publications and source records attributed to M D Dake.

At least 55 records · Page 3Linked to original sources
PubMed1998

Superior vena cava syndrome: treatment with catheter-directed thrombolysis and endovascular stent placement.

PURPOSE: To evaluate use of catheter-directed thrombolysis and/or endovascular stent placement to treat superior vena cava (SVC) syndrome. MATERIALS AND METHODS: Fifty-nine consecutive patients with SVC syndrome were studied. The cause was underlying malignancy in 43 and benign disease in 16. All patients underwent bilateral upper-extremity venography. The SVC was occluded in 31 cases and stenosed in 28. Twenty-seven patients underwent catheter-directed thrombolysis; 51 underwent endovascular stent placement. Patency was defined in terms of absence of symptoms and signs of SVC syndrome. RESULTS: Technical success was achieved in 56 of 59 patients (95%). Among 42 patients with underlying malignancy (mean follow-up, 7.0 months; range, 1-34 months), primary clinical patency was achieved in 33 (79%) and secondary clinical patency was achieved in 39 (93%). Among 13 patients with benign disease (mean follow-up, 17.0 months; range, 1-27 months), primary clinical patency was achieved in 10 (77%) and secondary clinical patency was achieved in 11 (85%). Four patients were lost to follow-up. Periprocedural mortality and morbidity rates were 3% (two of 59 patients) and 10% (six of 59 patients), respectively. CONCLUSION: Catheter-directed thrombolysis and endovascular stent placement is a safe and effective treatment for SVC syndrome.

Contraindications↗
PubMed1998

1998 ARRS President's Award. The potential of in vivo vascular tissue engineering for the treatment of vascular thrombosis: a preliminary report. American Roentgen Ray Society.

OBJECTIVE: Current gene therapy and tissue engineering protocols suffer from a number of inherent limitations. In this study, we examine the feasibility of a new approach for the treatment of vascular thrombosis: in vivo tissue engineering. MATERIALS AND METHODS: Rabbit femoral veins were transfected in situ with either a previously characterized adenoviral-construct-expressing tissue plasminogen activator or a viral (adenoviral-construct-expressing beta-galactosidase) or nonviral (buffer) control and used as cross sections (n = 3). Treated veins were then harvested and grafted into the ipsilateral common femoral artery as an interposition vein graft. A potent stimulus for thrombus formation was then introduced into the recipient artery downstream of the graft. Six days later, the rabbits were sacrificed, and the grafts and downstream arteries were harvested. Vessel segments were then examined for thrombus according to defined anatomic zones. Transfection efficiency and presence of smooth muscle cells in the vein graft were also evaluated. RESULTS: The engineered vein graft showed a significant reduction in thrombus formation within both the graft and the downstream artery relative to nonviral (buffer) and viral (adenoviral-Rous sarcoma virus beta-galactosidase [Adv/RSV-betagal]) controls. Underlying endothelial cell transfection efficiency of 90% was observed in viral controls (Adv/RSV-betagal). A 2.4-fold increase in smooth muscle alpha-actin positive cells in the engineered vein graft was seen compared with nonviral (phosphate-buffered saline) controls. A 10-fold increase in smooth muscle alpha-actin-positive cells in the engineered vein graft relative to viral (Adv/RSV-betagal) controls was also observed. CONCLUSION: In vivo tissue engineering is a new paradigm in molecular medicine that is a viable alternative to conventional gene therapy and tissue engineering for the treatment of vascular thrombosis.

Animals↗
PubMed1997

Simultaneous abdominal aortic replacement and thoracic stent-graft placement for multilevel aortic disease.

PURPOSE: Patients with aneurysmal disease involving both the descending thoracic and abdominal aorta have historically required simultaneous or sequential conventional operations, but the morbidity rate is high with either approach in these patients, who often exhibit coexisting cardiopulmonary disease. Transluminally placed endovascular grafts have recently been developed for repair of aortic aneurysms, and we have implemented these techniques to eliminate the need for a thoracotomy in patients with multilevel aortic disease. METHODS: Since January 1994, 18 patients have undergone conventional abdominal aortic replacement with endovascular stent-graft placement into the descending thoracic aorta under fluoroscopic guidance through a 10 mm Dacron side limb off the abdominal graft. Abdominal aortic replacement required a tube graft in eight patients and bifurcated grafts in 10 patients. Thoracic stent-grafts (custom fabricated, woven Dacron covered, self-expandable stents) averaged 12.2 +/- 4.2 cm (mean +/- SD) in length. RESULTS: One patient died, resulting in a hospital mortality rate of 6%. No patients required further surgical intervention to treat their aortic disease. Seventeen patients (94%) are currently well 14 +/- 8 months after surgery (range, 3 to 29 months) with completely excluded thoracic aortic disease, no stent migration, and no change in stent configuration documented by serial radiologic examinations. CONCLUSIONS: Simultaneous abdominal aortic replacement and deployment of a thoracic stent-graft can safely exclude multilevel aortic aneurysmal disease and may be a valuable treatment option for these otherwise high-risk patients.

Aged↗
PubMed1997

Traumatic thoracic aortic aneurysm: treatment with endovascular stent-grafts.

PURPOSE: To demonstrate the feasibility and safety of endovascular stent-graft placement for treatment of traumatic aortic aneurysm. MATERIALS AND METHODS: Ten patients with traumatic aortic aneurysm were treated with endovascular stent-grafts. Three patients had an acute traumatic aneurysm; seven had a chronic aneurysm. Stent-grafts were constructed from modified Z-stents covered with woven polyester or expanded polytetrafluoroethylene graft material and were deployed through a 20-24-F delivery sheath in an exposed artery located remotely from the lesion. RESULTS: Stent-graft placement and thrombosis of the aneurysmal sac were successful in all patients. Major complications were encountered in three patients after endovascular treatment. One patient had a peri-graft leak; complete thrombosis of the aneurysmal sac was achieved after coil embolization of the leak. Transposition of the left subclavian artery was necessary to relieve left arm ischemia in another patient. In the third patient, stent placement in the left main stem bronchus was needed to relieve left lung atelectasis. All patients were alive and without complications during the follow-up period (mean, 15 months). CONCLUSION: Transluminal placement of endovascular stent-grafts is a technically feasible method for treatment of traumatic thoracic aortic aneurysm and may be an effective alternative to open-chest surgery.

Accidents, Traffic↗
PubMed1997

Thoracic aortic aneurysm repair with endovascular stent-grafts.

The purpose of the study was to describe the clinical experience is using endoluminal stent-grafts for the treatment of thoracic aortic aneurysms in high-risk patients. Patients with aneurysms of the descending thoracic aorta who were considered high surgical risks underwent evaluation for endoluminal repair. The prosthesis was constructed from Z stents covered with polyester fabric using dimensions based upon preprocedural computed tomography scans and angiography. Through a femoral arteriotomy or left retroperitoneal flank incision, a 22-24 Fr delivery catheter was inserted and advanced through the aorta to the target site under fluoroscopic guidance in the operating suite. The stent-graft prosthesis was deployed at the site of the aneurysm. 44 patients (36 male, 8 female; mean age 36 years) underwent stent-graft repair for thoracic aneurysms (mean diameter 6.3 cm). The deployment was technically successful in all cases, with complete aneurysm thrombosis in 88%. The 30-day perioperative mortality rate was 6.8% and 35-month actuarial survival was 82%. There were no cases of stent migration, surgical conversion or intraprocedural death. Paraplegia occurred in two patients who underwent simultaneous surgical infrarenal aortic aneurysm repair immediately followed by stent-graft placement for a coexisting thoracic aneurysm. The conclusion was that placement of endoluminal stent-grafts for repair of thoracic aortic aneurysms is technically feasible in high-risk patients in whom conventional surgery is contraindicated. Long-term studies are needed to determine protection against aneurysm rupture and patient survival.

Adult↗
PubMed1997

Covered stent placement for neurovascular disease.

We describe an endovascular technique in which covered stents were used to occlude a parent vessel. In one patient, with a giant paraclinoid aneurysm, a Gortex-covered Palmaz stent was used to occlude the cervical internal carotid artery and to create thrombosis in the aneurysm. In the second patient, with a high-flow vertebrojugular fistula, a hooded stent provided definitive treatment after an attempt to close the fistula by detachable balloon therapy failed. Follow-up of these patients revealed stable stent position and no untoward effects of permanent vessel occlusion.

Adult↗
PubMed1997

Stent-graft repair of thoracic aortic aneurysms.

Aneurysmal disease of the thoracic aorta continues to be a very challenging management problem for physicians because of the many comorbidities harbored by these patients, as well as the morbidity of the conventional open repair via left thoracotomy. In a combined effort between interventional radiology and cardiovascular surgery, an endovascular stent graft repair has been devised for these patients in an effort to reduce morbidity. This report documents the results in the first 108 patients so treated. The graft itself, custom-made for each individual, is composed of interlocked, self-expanding "Z" stents covered with a woven Dacron graft. Compressed in a loading capsule, the graft can then be advanced through a 27-French (outside diameter; OD) sheath, which is positioned within the aneurysm under fluoroscopic guidance. Relatively normal 2- to 3-cm segments of proximal and distal aorta allow an adequate friction seal to prevent stent graft dislodgement and also provide a hemostatic seal to obliterate aneurysm filling. Complete aneurysm thrombosis was achieved primarily in 103 patients. There were 10 deaths (9.25%) within the first 30 days, four of which were directly attributable to the stent graft procedure. Perioperative strokes occurred in four patients, and there were four instances of paraplegia. There have been two documented stent graft failures in a mean follow-up of 21.8 months (range, 1 to 57 months). Although the long-term durability of this procedure remains unknown, we believe this less invasive endovascular approach will prove to be an effective and less morbid treatment for aneurysmal disease of the descending thoracic aorta.

Aortic Aneurysm, Thoracic↗
PubMed1996

Endovascular stent-graft repair of thoracic aortic aneurysms.

Conventional repair of aneurysms of the descending thoracic aorta entails thoracotomy and graft interposition. For elderly patients and those with previous operations, obesity, respiratory insufficiency, or other comorbidities, such a procedure entails significant mortality and morbidity. Transluminal stent-graft placement offers an alternative approach with potentially less morbidity and quicker recovery; however, the effectiveness and durability of stent-grafts remain uncertain. METHODS: Since July 1992, thoracic aortic stent-grafts have been placed in 44 patients with a variety of pathologic conditions. Each graft was individually constructed from self- expanding, stainless-steel Z stents covered with a woven Dacron polyester fabric graft. Craft dimensions were determined from spiral computed tomographic scans. All implants were performed in the operating theater under fluoroscopic and transesophageal echocardiographic guidance. Follow-up was by computed tomography and contrast angiography in all cases. PATIENT DATA: There were 36 men and 8 women. Mean age was 66 years (range 35 to 88 years). Mean aneurysmal diameter was 6.3 cm (range 4.0 to 9.4 cm). Etiologies included 23 degenerative aneurysms, four posttraumatic aneurysms, four pseudoaneurysms, and one chronic aortic dissection. RESULTS: There were three early deaths (<30 days) and two late deaths. One early death resulted from graft failure. There were two instances of paraparesis or paraplegia, with one associated early death. A single stent was deployed in 27 patients, two stents were required in 14 patients, and three stents were required in three patients. In 23 patients, vascular access was attained through the femoral artery; abdominal aortic access, either native or graft, was necessary in the remaining 21 patients. Twelve grafts were placed in conjunction with open abdominal aortic surgical procedures. Mean follow-up (98% complete) was 12.6 months (range 1 to 34 months). One late death occurred from aneurysmal expansion and rupture in a patient with a persistent midgraft leak. The second late death may have resulted from aneurysmal rupture. Immediate thrombosis was achieved in 36 patients, and late thrombosis was achieved in three others. Failure to achieve complete aneurysmal thrombosis occurred in five patients, however, and one individual (previously noted) died of aneurysmal expansion and rupture; the remaining four are being carefully monitored. Only one patient has required conversion of the stent to an open procedure; a contained rupture of the false lumen of a chronic dissection eventually necessitated total descending thoracic aortic exclusion. CONCLUSIONS: These early results support the hypothesis that endovascular stent-graft placement may be a safe and durable treatment for selected patients with aneurysmal disease of the descending thoracic aorta. Large introducer size (26F outer diameter) and relatively limited angulation capability, as well as imprecise deployment techniques, currently limit its applicability. Distal embolization and stent migration have not been observed. Failure to achieve complete aneurysmal thrombosis may allow continued aneurysmal expansion and rupture. Further follow-up is clearly necessary to evaluate the true long-term effectiveness of this procedure.

Adult↗
PubMed1996

Aortic dissection: percutaneous management of ischemic complications with endovascular stents and balloon fenestration.

PURPOSE: The purpose of this study was to evaluate endovascular stenting (EVS) and balloon fenestration (BF) of intimal flaps for the management of lower extremity, renal, and visceral ischemia in acute or chronic aortic dissection. METHODS: Twenty-two patients (16 male, 6 female) with a median age of 53 years (range 35 to 77 years) underwent percutaneous treatment for peripheral ischemic complications of 12 type A (five acute, seven chronic) and 10 type B (nine acute, one chronic) aortic dissections. RESULTS: Ten patients had leg ischemia, 13 had renal ischemia, and 6 had visceral ischemia. Sixteen patients were treated with EVS including 11 with renal, 6 with lower extremity, 2 with superior mesenteric artery, and 2 with aortic stents. Three patients had BF of the intimal flap, and three had BF in combination with EVS. Revascularization with clinical success was achieved in all 22 patients. Two patients died 3 days and 13.4 months after the procedure was performed, respectively. Of the remaining 20 patients, 1 is lost to follow-up, and 19 have persistent relief of clinical symptoms. Mean follow-up time is 13.7 months (range 1.1 to 46.5 months). One case was complicated by guidewire-induced perinephric hematoma. CONCLUSION: EVS and BF provide a safe and effective percutaneous method for managing peripheral ischemic complications of aortic dissection.

Acute Disease↗
PubMed1996

Perspective volume rendering of CT and MR images: applications for endoscopic imaging.

PURPOSE: To use perspective volume rendering (PVR) of computed tomographic (CT) and magnetic resonance (MR) imaging data sets to simulate endoscopic views of human organ systems. MATERIALS AND METHODS: Perspective views of helical CT and MR images were reconstructed from the data, and tissues were classified by assigning color and opacity based on their CT attenuation or MR signal intensity. "Flight paths" were constructed through anatomic regions by defining key views along a spline path. Twelve movies of the thoracic aorta (n=3), tracheobronchial tree (n=4), colon (n=3), paranasal sinuses (n=1), and shoulder joint (n=1) were generated to display images along the flight path. All abnormal results were confirmed at surgery. RESULTS: PVR fly-through enabled evaluation of the full range of tissue densities, signal intensities, and their three-dimensional spatial relationships. CONCLUSION: PVR is a novel way to present volumetric data and may enable noninvasive diagnostic endoscopy and provide an alternate method to analyze volumetric imaging data for primary diagnosis.

Aorta, Thoracic↗
PubMed1996

True lumen obliteration in complicated aortic dissection: endovascular treatment.

PURPOSE: To evaluate endovascular treatment of ischemic complications caused by true lumen obliteration in aortic dissection. MATERIALS AND METHODS: Endovascular techniques were used to treat true lumen obliteration in 11 patients with complicated aortic dissection. In all cases, the true lumen was compressed to a paper-thin sliver by the expanded false lumen. Two patients had Stanford type A (chronic) and nine had type B (six acute, three chronic) dissections. Obliteration of the true lumen was associated with branch vessel ischemia that included renal (n = 7), mesenteric (n = 6), and lower-extremity (n = 6) arterial compromise. Two patients were treated with aortic stents, four with balloon fenestration of the intimal flap, and three with both stent placement and fenestration. In two patients, ischemic complications caused by true lumen obliteration could not be treated with endovascular techniques. RESULTS: Revascularization was technically successful with relief of clinical symptoms in nine patients. Revascularization was unsuccessful in one patient in whom surgical revascularization of the superior mesenteric artery was necessary and in one in whom hypertension was managed medically. One patient developed thrombosis of a renal artery in which a stent had been placed. The 30-day mortality rate was 9%, and the mean follow-up was 10.1 months (range, 2 weeks to 39 months). CONCLUSION: True lumen obliteration can be safely and effectively treated with endovascular stent placement and balloon fenestration.

Aortic Dissection↗
PubMed1996

Catheter-directed thrombolysis for iliofemoral venous thrombosis.

The combination of catheter-directed thrombolytic therapy and endovascular stenting is a new and promising approach for treating acute and chronic thrombotic iliofemoral venous occlusions on the basis of the authors' initial experience in a small group of patients. In acute DVT, catheter-directed techniques provide more complete lysis than systemic infusions and early, aggressive interventional therapy may spare the patient from the life-long disability associated with the postphlebitic syndrome, by preserving valve function and eliminating the venous outflow obstruction. Immediate postthrombolysis venography can evaluate the underlying vein and assess the need for adjunctive treatment with angioplasty and/or stents. Urokinase has a high degree of safety with few complications when a catheter-directed approach rather than systemic infusion is used. Even patients with chronic DVT can benefit by reducing the obstruction to venous outflow if the occlusion is limited to the iliac vein and/or the inferior vena cava. Long-term follow-up studies are necessary to evaluate patency rates of the treated veins, determine whether successfully treated limbs have a lower frequency of recurrent DVT, and ascertain the frequency of chronic venous insufficiency compared with that in patients treated with anticoagulation alone. Based on our initial experience, a National Venous Thrombosis Registry was established in October 1994. The purpose of this multidisciplinary Registry is to prospectively document the long-term results of catheter-directed thrombolytic therapy for patients with iliofemoral DVT, with data now being collected from 40 leading medical centers around the United States. We hope that endovascular techniques for iliofemoral DVT will significantly reduce the immediate and long-term complications commonly associated with this difficult and often misunderstood clinical problem.

Acute Disease↗
PubMed1996

Endovascular stenting of an aortopulmonary fistula presenting with hemoptysis. A case report.

We present a 45 year old man with massive hemoptysis due to an aortopulmonary fistula. Our patient had a history of a previous patent ductus arteriosus repair which was complicated by a previous aortopulmonary fistula. Computed tomography of the chest and aortography made the diagnosis of a recurrent aortopulmonary fistula. Because of the history of previous surgical aortic procedures, repair of the fistula was completed through a retroperitoneal aortotomy with intravascular insertion of an expandable stainless steel stent covered by a polyester graft. The patient has had no hemoptysis or computed tomographic evidence of fistula recurrence thirty eight months after the procedure.

Aneurysm, False↗