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Biomedical subjects

Karthikeshwar Kasirajan

Publications and source records attributed to Karthikeshwar Kasirajan.

At least 19 recordsLinked to original sources
PubMed2006

Thoracic endografts: procedural steps, technical pitfalls and how to avoid them.

Recent US Food and Drug Administration (FDA) approval of a thoracic endograft has created explosive interest among physicians to learn to use this minimally invasive technology. The level of interest is similar to the period more than a decade ago, following FDA approval of infrarenal abdominal endografts, which initiated the "endo" revolution among vascular specialists. Many physicians view the descending thoracic aorta as a simple, straight tube and, thus, technically less challenging than endografts for infrarenal abdominal aortic aneurysm. However, the thoracic aorta presents certain unique features that make this a challenging procedure. Technical challenges posed by the thoracic aorta have resulted in a significant time-lag (since release of abdominal aortic aneurysm endografts), testing the ability of engineers and physicians to devise and complete trials successful enough for FDA approval of thoracic endografts. This article addresses the various procedural steps and tips on avoiding pitfalls.

Angiography↗
PubMed2006

Combination therapies for deep venous thrombosis.

Nearly 1 million patients are treated for deep venous thrombosis annually in the United States, typically with anticoagulant therapy alone. While anticoagulation reduces risk for pulmonary embolism, up to two-thirds of patients experience some degree of postthrombotic syndrome. This review details the recent introduction of a variety of novel mechanical thrombectomy devices that, in combination with local delivery of thrombolytic agents, offers a new approach for rapid and effective removal of venous thrombus, while minimizing attendant risks of bleeding complications.

Catheterization↗
PubMed2005

Safety and efficacy of carotid arteriography in vascular surgery practice.

OBJECTIVE: Carotid arteriography (CA) is an important method of assessing carotid artery occlusive disease and is the best method of planning for carotid angioplasty and stent placement (CAS). This study compared the results of CA performed by vascular surgeons in a contemporary series against widely recognized interdisciplinary quality standards for this procedure. Although many vascular surgeons perform CA, there is a paucity of data about its safety, efficacy, and compliance with quality standards in vascular practice. The importance of quality CA will likely increase as CAS emerges to assume a broader clinical role. METHOD: Carotid arteriograms performed by seven vascular surgeons at three institutions from September 2000 to May 2004 were reviewed. These results were compared with quality standards for the performance of CA. RESULTS: Five hundred three carotid arteriograms were performed over 45 months. Indications for the procedure were extracranial cerebrovascular disease (86%), trauma (5%), and other conditions (9%). Indications for the procedure were appropriate in 100% of patients (as determined by guidelines document) and exceeded the recommended standard of appropriate indications in 99%. All procedures successfully provided the information required, exceeding the threshold of 98% for procedural success. Reversible neurologic deficits occurred in 0.6% (two transient ischemic attacks and one stroke) compared with the threshold of 2.5%. A permanent neurologic deficit occurred in 0.2% (1 patient) compared with the published guideline of 1% after carotid arteriography. Major non-neurologic complications occurred in 1.2% (6 patients), less than the standard of 2.0%. CONCLUSIONS: The safety and efficacy of a contemporary series of CA performed in vascular surgery practice compared favorably with recognized interdisciplinary quality standards for this procedure. Ensuring safe and effective CA is likely to support the successful growth of CAS as a treatment option.

Aged↗
PubMed2005

Endovascular management of ruptured, mycotic abdominal aortic aneurysm.

Patients with mycotic aneurysms have a high mortality rate. The standard surgical approach can be exceptionally difficult and fraught with complications. There has been reluctance to insert an endograft into an infected field. We believe that this thought should be challenged and present a case of a successful endovascular repair of a ruptured, mycotic abdominal aortic aneurysm. The patient is a 63-year-old man with severe medical comorbidities and methicillin-sensitive Staphylococcus aureus. He required 6 units of red blood cells on admission. Magnetic resonance angiography (MRA) showed a contained rupture of his distal abdominal aorta, and he underwent emergent endovascular repair. An aortomono-iliac device (12 mm x 10 cm iliac extension limb) was inserted along with coil embolization of his right common iliac artery and a femoral-femoral bypass. He did not require additional transfusions after the procedure and was discharged in good condition. He is on antibiotics and doing well 1 year post-op. Endovascular management of ruptured, mycotic aneurysms is feasible. In fact, it is an attractive approach for a medically compromised patient subset that would carry an exceptionally high mortality rate with traditional surgical repair. Further follow-up is necessary to determine its long-term efficacy.

Aneurysm, Infected↗
PubMed2005

What is the latest in inventory for carotid stenting and cerebral protection?

Carotid angioplasty is fast being incorporated into the treatment options for patients with carotid occlusive disease. The results of the SAPPHIRE and ARCHER trials have demonstrated that carotid angioplasty and stenting with the use of cerebral protection devices is not inferior to open surgical endarterectomy in high-risk patients. The limiting step for percutaneous carotid interventions was the potential for cerebral embolization during the intervention. However, the ready availability of several embolic protection devices has placed this technology into the hands of many endovascular specialists. A brief outline of the basic inventory necessary for a carotid stent program is presented.

Angioplasty, Balloon↗
PubMed2004

Determinants of in-hospital mortality and length of stay for acute intestinal gangrene.

BACKGROUND: Intestinal gangrene carries high operative mortality and morbidity rates. This study was undertaken to identify predictors of in-hospital death and length of stay. METHODS: Retrospective review of hospital data over a 6-year period identified 107 patients diagnosed with acute bowel gangrene. RESULTS: Among the baseline factors that had a significant univariable association with mortality (51%) were age (P = 0.04), symptom duration (P = 0.01), preoperative and postoperative pH and lactic acid (P < or = 0.02), history of hypertension (P = 0.001), and renal failure (P = 0.008). Symptom duration and history of hypertension were independent risk factors for mortality. Longer length of stay was univariably associated with symptom duration (P = 0.006), systemic acidosis (P < or =0.005), vascular etiology (P = 0.04), amount of resected bowel (P = 0.001), and need for second-look procedures (P <0.001). CONCLUSIONS: The presence of multiple risk factors predictive of a high mortality rate may aid more realistic decision making for physicians, patients, and family members.

Acute Disease↗
PubMed2004

Early outcome of "cutting" balloon angioplasty for infrainguinal vein graft stenosis.

BACKGROUND: Recurrent stenotic lesions associated with vein graft bypass grafts are often fibrous and smooth. Unlike de novo atherosclerotic lesions, they respond poorly to balloon angioplasty, and may often result in a dissection requiring stent placement to avoid early recurrent thrombosis or open repair of residual stenosis. A novel balloon designed with three or four longitudinally placed 0.127-mm atherotomes was used at angioplasty to treat focal peripheral vein graft stenosis, in an attempt to minimize dissection by producing a controlled plaque fracture. METHODS: Over 11 months, patients with focal (<2 cm) peripheral vein graft stenosis underwent cutting balloon angioplasty (Boston Scientific, San Diego, Calif) at two separate centers. Baseline patient demographic data, type of bypass, velocity at pre-procedural and post-procedural duplex scanning, procedural results, complications, and type of long-term anticoagulation were recorded. Follow-up consisted of duplex ultrasound scanning at 1, 3, and 6 months and every 6 months for 2 years. RESULTS: The mean age of the patients was 66.8 +/- 10 years. No intent to treat failure was noted. In most patients a 4-mm balloon was used (15 of 19) to treat 10 above-knee vein bypass grafts and 9 below-knee vein bypass grafts. No patient required placement of a stent or conversion to open surgery because of recoil, dissection, or suboptimal angioplasty. The mean velocity at pre-procedure duplex scanning at the site of vein graft stenosis was 373 +/- 56.8 cm/s, and the mean velocity post-treatment at 1-month follow-up was 144 +/- 50 cm/s. The mean length of stay was 26 +/- 32 hours. Overall, four patients continued to receive warfarin anticoagulation therapy, in addition to aspirin. During a mean follow-up of 11.4 +/- 7 months, recurrent stenosis developed in one patient. No other complications or graft recurrent thrombosis was noted. CONCLUSION: Cutting balloon angioplasty may help overcome hoop stress early, by producing a controlled, longitudinal neointimal lesion laceration and thereby facilitating a fracture line along predetermined microincisions. Our study results demonstrate acceptable early outcomes, with no requirement for bail-out stenting or open surgery.

Aged↗
PubMed2003

Acute thoracic aortic trauma: a comparison of endoluminal stent grafts with open repair and nonoperative management.

The magnitude of injury necessary to cause a traumatic aortic tear often results in high mortality. Open surgery in these patients is often not well tolerated. The purpose of this study was to compare the outcomes of three different treatment options in patients with traumatic aortic injuries. This was a retrospective review of a prospectively maintained computer database. Over a period of 33 months, 27 patients were diagnosed with thoracic aortic tears on the basis of a computed tomogram or a diagnostic angiogram. All patients were initially seen by trauma surgery staff and managed nonoperatively ( n = 12) if the predicted mortality due to associated injuries approached 100%. Thoracic surgery staff were consulted on all other patients, and open surgical repair was performed in 10 patients. Thoracic stent grafts were used in five patients because of inability to ventilate following an attempted thoracotomy ( n = 2) or associated organ injury that prohibited anticoagulation (head +/- liver injury, n = 3). Overall, patients in the endovascular group had a higher injury severity score than that of the open surgical group (42 +/- 9 vs. 32 +/- 11). However, mortality was lowest in the endovascular group (20%), higher in the open surgical group (50%), and highest in the nonoperative group (92%). No paraplegia was noted, and all surviving patients have been free of complications during the follow-up period. Due to the small number of patients in each treatment, no strong recommendations can be made. However, the results of thoracic stent grafts for patients with traumatic thoracic pseudoaneurysms may prove to be a safer and less invasive treatment option.

Adult↗
PubMed2003

Comparison of nonneurological events in high-risk patients treated by carotid angioplasty versus endarterectomy.

OBJECTIVE: To compare results of carotid angioplasty and stenting (CAS) with carotid endarterectomy (CEA) in high cardiac risk patients. METHODS: Patients ineligible for carotid revascularization by North American Symptomatic Carotid Endarterectomy Trial/Asymptomatic Carotid Atherosclerosis Study criteria were treated with CAS (n = 11) or CEA (n = 10). RESULTS: Significant numbers had cardiac (CAS 72%, CEA 60%; P = 0.66) and hypertensive (CAS 82%, CEA 80%; P = 0.64) risk factors. Adverse hemodynamic events were more frequent in the CAS group (CAS 73%, CEA 20%; P = 0.03). Major complications were noted in 1 patient in each group (CAS, myocardial infarction; CEA, death). Postoperative stay was similar (CAS 2.1 +/- 1.4, CEA 1.8 +/- 1.1 days; P = 0.60). However, 4 in the CAS group were readmitted within 1 month (congestive heart failure 2, myocardial infarction 1, rest pain 1), compared with no new events in the CEA group (P = 0.09). CONCLUSIONS: Currently, the use of CAS in patients with cardiac risk factors may not be justifiable.

Aged↗
PubMed2003

Technique and results of transfemoral superselective coil embolization of type II lumbar endoleak.

OBJECTIVE: This study was undertaken to describe the technique of transfemoral superselective coil embolization of type II endoleak and its influence on abdominal aortic aneurysm diameter. METHODS: Over 23 months, 104 aortic stent grafts were deployed to exclude abdominal aortic aneurysms, at an academic medical center. Increase in aneurysm diameter and perigraft findings on contrast material-enhanced computed tomography scans prompted arteriography. Procedures were performed solely by vascular surgeons in a surgical angiography suite. In 7 patients aneurysm access was via the iliolumbar branches of the internal iliac artery, and in 1 patient aneurysm access was via the inferior mesenteric artery through the arc of Riolan from the superior mesenteric artery. Coaxial catheters were placed to gain access to the aneurysm (8F to 5F to 3F, or 5F to 3F). A 3F Tracker18 was the most distal catheter through which an assortment of 0.018 microcoils were deployed within the aneurysm, and the origin of the feeding vessels when possible. RESULTS: Aneurysm diameter increased 0.48 +/- 0.2 cm over 10.8 +/- 5 months before superselective coil embolization. In 6 of 8 patients superselective coil embolization embolization resulted in a mean decrease in aneurysm diameter of 1.3 +/- 1.2 cm over 9 +/- 3.2 months. Failure was presumed due to inability to reach the aneurysm sac in 1 patient and was associated with oral anticoagulation in 1 other patient. CONCLUSION: Proper identification of the source of type II endoleak and its complete occlusion, combined with aneurysm sac coiling, may result in prompt decrease in aneurysm size.

Aged↗
PubMed2003

Is carotid angioplasty and stenting more cost effective than carotid endarterectomy?

OBJECTIVE: Carotid angioplasty and stenting (CAS) has been advocated as a minimally invasive and inexpensive alternative to carotid endarterectomy (CEA). However, a precise comparative analysis of the immediate and long-term costs associated with these two procedures has not been performed. To accomplish this, a Markov decision analysis model was created to evaluate the relative cost effectiveness of these two interventions. METHODS: Procedural morbidity/mortality rate for CEA and costs (not charges) were derived from a retrospective review of consecutive patients treated at New York Presbyterian Hospital/Cornell (n = 447). Data for CAS were obtained from the literature. We incorporated into this model both the immediate procedural costs and the long-term cost of morbidities, such as stroke (major stroke in the first year = $52,019; in subsequent years = $27,336/y; minor stroke = $9419). We determined long-term survival rate in quality-adjusted life years and lifetime costs for a hypothetic cohort of 70-year-old patients undergoing either CEA or CAS. Our measure of outcome was the cost-effectiveness ratio. RESULTS: The immediate procedural costs of CEA and CAS were $7871 and $10,133 respectively. We assumed major plus minor stroke rates for CEA and CAS of 0.9% and 5%, respectively. We assumed a 30-day mortality rate of 0% for CEA and 1.2% for CAS. In our base case analysis, CEA was cost saving (lifetime savings = $7017/patient; increase in quality-adjusted life years saved = 0.16). Sensitivity analysis revealed major stroke and death rates as the major contributors to this differential in cost effectiveness. Procedural costs were less important, and minor stroke rates were least important. CAS became cost effective only if its major stroke and mortality rates were made equivalent to those of CEA. CONCLUSION: CEA is cost saving compared with CAS. This is related to the higher rate of stroke with CAS and the high cost of stents and protection devices. To be economically competitive, the mortality and major stroke rates of CAS must be at least equivalent if not less than those of CEA.

Aged↗
PubMed2003

The Trellis Thrombectomy System in the treatment of acute limb ischemia.

PURPOSE: To report the use of a new percutaneous mechanical thrombectomy device in the treatment of acute limb-threatening ischemia. TECHNIQUE: The Trellis Thrombectomy System is a 7-F drug dispersion catheter that features a treatment segment isolated by proximal and distal occlusion balloons, which help prevent distal embolization and systemic release of the infused thrombolytic agent. After inflating the distal balloon, the thrombolytic agent is infused and held at the target site by inflation of the proximal balloon. An oscillating dispersion wire optimizes dispersal of the thrombolytic agent as the thrombus is mechanically fragmented. The liquefied thrombus is then aspirated. Four consecutive patients with acute lower extremity ischemia secondary to bypass graft thrombosis were treated with the Trellis thrombectomy catheter. Overall, 95% of thrombus was successfully removed from the treatment zone, with no device-related complications. Only one patient required adjunctive thrombolytic therapy after thrombectomy with the Trellis device. CONCLUSIONS: The Trellis thrombectomy device is a safe and effective technique to isolate the infused thrombolytic agent in association with mechanical fragmentation for rapid blood flow restoration.

Acute Disease↗
PubMed2003

Covered stents for true subclavian aneurysms in patients with degenerative connective tissue disorders.

PURPOSE: To report the endovascular repair of rare true aneurysms of the subclavian artery in patients with degenerative connective tissue disorders. CASE REPORTS: Two patients, one with Marfan syndrome and the other with idiopathic cystic medial necrosis, presented with 3 subclavian artery aneurysms. A Wallgraft and 2 Viabahn covered stents were used to successfully exclude these aneurysms. After 3 months, the Wallgraft thrombosed, but the contralateral Viabahn remained patent at the most recent examination 13 months after treatment. The other patient with the unilateral aneurysm had a patent Viabahn stent-graft at 10 months. CONCLUSIONS: Patients with degenerative connective tissue disorders may benefit from less invasive treatment with stent-grafts. The more flexible Viabahn stent-graft may be better able to adapt to arterial tortuosity. However, the long-term results of this new technique have not yet been established.

Adult↗
PubMed2003

Filter devices for cerebral protection during carotid angioplasty and stenting.

The risk of embolization during carotid artery stenting (CAS) has been the foremost reason for the cautious acceptance of this percutaneous alternative to carotid endarterectomy. To address this issue, numerous embolic protection devices are being evaluated as an adjunct to CAS for neuroprotection. Among the 3 main categories of these devices, distal filters, which trap embolic debris while maintaining distal cerebral perfusion, have attracted the most corporate interest. This review focuses on the emerging field of embolic protection filters for use in CAS.

Angioplasty, Balloon↗