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Patency of the Viabahn Stent Graft for the Treatment of Outflow Stenosis in Hemodialysis Grafts
Abstracts Gregory L. Moneta, MD, Section Editor
Meta-Analysis of Benefits of Portal-Superior Mesenteric Vein Resection in Pancreatic Resection for Ductal Adenocarcinoma Giovinazzo F, Turri G, Katz MH, et al. BJS 2016;103:179-91. Conclusions: There are increased postoperative mortality rates, higher rates of non-R0, positive margins, resection and worse survival after pancreatic resection with portal vein superior mesenteric vein (PV/SMV) resection. Summary: Pancreatic cancer is now the 4th leading cause of death from cancer in the United States. Five-year survival rates are generally <5% (Am Cancer Society. Cancer Facts & Figures: Atlanta; 2012). Pancreatic cancer is the only neoplasm for which there is not been a substantial increase in short- or long-term survival over the past 40 years (Quaresma M et al, Lancet 2015;385:1206-18). Major goal of surgery is to achieve complete resection (R0) of the tumor. When this is possible, even in presence of PV/SMV invasion, there is a 5-year survival rate of 20-25% (Sperti C et al, World J Surg 1997;21:195-200). There is no standard treatment, however, for patients with tumors infiltrating the PV/SMV confluence. In many centers, a more aggressive approach to PV/SMV resection has been adopted. The present meta-analysis evaluated the perioperative outcomes and overall survival of patients undergoing pancreatic resection combined with PV/SMV vein resection compared with those patients without PV/SMV resection with the aim of evaluating feasibility and influence on patient outcomes. A systematic search was performed of PubMed, Embase, and the Cochrane Library in accordance with PRISMA guidelines from the time of inception to 2013. Inclusion criteria were comparative studies including patients who underwent pancreatic resection with or without PV/SMV resection. One-, 3-, and 5-year survival were the primary outcomes. Twenty-seven studies were identified involving a total of 9005 patients (1587 with PV/SMV resection). Patients undergoing PV/SMV resection had an increased risk of postoperative mortality (RD, 0.01; 95% CI, 0.00-0.03; P ¼ .02) and of R1/R2 resection (RD, 0.09; 95% CI, 0.06-0.13; P < .001) compared with those undergoing standard surgery. One-, 3-, and 5-year survival were worse in the PV/SMV resection group (HR, 1.23; 95% CI, 1.07-1.43; P ¼ .005), 1.48 (95% CI, 1.14-1.91; P ¼ .004) and 3.18 (95% CI, 1.95-5.19; P < .001) respectively. Median overall survival was 14.3 months for patients undergoing pancreatic resection with PV/ SMV resection and 19.5 months for those without vein resection (P ¼ .063). Comment: Two previous meta-analyses have showed similar perioperative outcomes and long term survival with pancreatic resections with PV/SMV resection and standard resection when an R0 resection was achieved. However, theoretically there is likely more advanced disease in the patients undergoing PV/SMV resection and the real issue is whether patients with PV/SMV tumor involvement who undergo PV/SMV resection will do better than those who were merely treated with adjuvant therapy alone or just pancreatic and biliary drainage. In the meantime, one can expect the trend for more aggressive resection of pancreatic cancer to continue as adjuvant therapy evolves and vascular and oncologic surgeons become more comfortable with PV/SMV resection and reconstruction.
Patency of the Viabahn Stent Graft for the Treatment of Outflow Stenosis in Hemodialysis Grafts Carmona J, Rits Y, Jones B, et al. Am J Surg 2016;211:551-4. Conclusions: Dialysis access grafts with outflow stenosis treated with Viabahn covered stents for the outflow stenosis have superior patency to arteriovenous grafts treated with angioplasty alone 12 months after treatment. Treatment results at earlier periods are comparable. Summary: Stenosis at the venous anastomosis is the most common reason for hemodialysis access graft malfunction and failure. Angioplasty and/or stent placement have been used for almost 2 decades as an option to treat these lesions to try and prolong the life of a dialysis access. A recent study indicated that stent grafts appeared to provide longer patency when used to treat venous anastomotic lesions of hemodialysis access graft compared to PTA alone (Vogel PM, J Vasc Interv Radiol 2005;16:1619-26). Covered stents therefore potentially make for prolonged functional patency of
hemodialysis access grafts and decreased morbidity of reintervention and ultimately less access abandonment. The purpose of this study was to evaluate arteriovenous graft (AVG) patency when failing grafts were treated with a Viabahn covered stent or PTA alone for outflow stenosis. This is a retrospective review of all patients undergoing endovascular interventions for failing grafts at a single institution between January 2010 and July 2013. Fortyfour patients were identified who were treated with PTA alone (n ¼ 11) and with Viabahn stent grafts (n ¼ 33) for stenosis at the vein to graft anastomosis. Patient demographics, procedural success, and intraoperative complications were recorded as well as graft patency at 3, 6, and 12 months. Graft patency was reviewed and compared with PTA alone. There were no statistically significant differences between the two groups regarding gender, prevalence of diabetes, hypertension, coronary artery disease, or peripheral arterial disease. Primary technical success, defined as a residual stenosis of #10%, was achieved in 100% of cases. Follow-up was determined by flow velocities during dialysis and with ultrasound imaging. At 12 months, 88% (29/33) of grafts with stents were functional vs 36.4 % (4/11) of those with PTA alone. Primary patency of the stent group was 61%, 52%, and 42% at 3, 6, and 12 months, respectively, vs 64%, 45%, and 9% in the PTA group. Comment: This was a small and nonrandomized retrospective study, but it does suggest that use of covered stents should perhaps be more widely considered for treatment of venous anastomosis stenosis in hemodialysis access grafts. Previous studies have not been able to consistently show a clear advantage of stent deployment to improve AV graft patency. The Viabahn stent, however, is heparin bonded, self-expanding and more flexible than previous stents employed and this may explain part of the benefit observed here. However, they are expensive, and before their use can be recommended widely, results here should be confirmed by larger, more rigorously designed studies.
Retinal Artery Occlusion and the Risk of Stroke Development: Twelve-Year Nationwide Cohort Study Rim TH, Han J, Choi YS, et al. Stroke 2016;47:376-82. Conclusions: Retinal artery occlusion (RAO) is significantly associated with subsequent stroke. Summary: RAO can lead to permanent vision loss. The retina is a component of the nervous system, as it is basically an extension of the diencephalon and originates from the neural tube, which is an embryologic part of the brain. RAO and stroke share a common pathophysiological mechanism of thromboembolism and common risk factors of hypertension, diabetes and hyperlipidemia (Hayreh SS, Prog Retin Eye Res 2005;24:493519). In the current study, the authors investigated possible association between RAO and subsequent risk of stroke occurrence based on cases of RAO and controls obtained from a nationwide representative sampling of 1,025,340 adults. The data were collected from the Korean National Health Insurance Service which comprised 1,025,340 random subjects. Patients with RAO were enrolled with initial diagnosis of either central or other RAO between January 2004 and December 2013 (n ¼ 401). The comparison group was composed of randomly selected subjects (five per RAO patient; n ¼ 2003) that were matched to the RAO group according to socio-demographic factors and year of RAO diagnosis. Each patient was tracked until 2013. Statistical analysis was by Cox proportional hazard regression. Stroke occurred in 15% of the RAO group and 8% of the comparison group (P < .001). RAO was associated with an increased risk of stroke occurrence (HR, 1.78; 95% CI, 1.32-2.41). The magnitude of RAO effect for stroke was larger among younger adults aged <65 years (HR, 3.11) than older adults aged $65 years (HR, 1.26). However, risk of subsequent stroke was significantly increased in older patients $65 years at the 4 year follow-up (HR, 1.58; 95% CI, 1.01-2.48). Comment: Central RAO is associated with visible emboli in <20% of people. Branch RAO has a higher rate of visible emboli approaching 60%-70% (Hayreh SS, Retina 2007;27:276-89, and Savino PJ et al, Arch Ophthalmol 1977;95:1185-9). A 2012 study from Taiwan reported similar results (Chang YS et al, Am J Ophthalmol 2012;154:645-52). Only 35% of ophthalmologists refer patients with central RAO to an emergency room (Atkins EJ et al, Am J Ophthalmol 2009;148:172-3); however, because
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Meta-Analysis of Benefits of Portal-Superior Mesenteric Vein Resection in Pancreatic Resection for Ductal Adenocarcinoma Giovinazzo F, Turri G, Katz MH, et al. BJS 2016;103:179-91. Conclusions: There are increased postoperative mortality rates, higher rates of non-R0, positive margins, resection and worse survival after pancreatic resection with portal vein superior mesenteric vein (PV/SMV) resection. Summary: Pancreatic cancer is now the 4th leading cause of death from cancer in the United States. Five-year survival rates are generally <5% (Am Cancer Society. Cancer Facts & Figures: Atlanta; 2012). Pancreatic cancer is the only neoplasm for which there is not been a substantial increase in short- or long-term survival over the past 40 years (Quaresma M et al, Lancet 2015;385:1206-18). Major goal of surgery is to achieve complete resection (R0) of the tumor. When this is possible, even in presence of PV/SMV invasion, there is a 5-year survival rate of 20-25% (Sperti C et al, World J Surg 1997;21:195-200). There is no standard treatment, however, for patients with tumors infiltrating the PV/SMV confluence. In many centers, a more aggressive approach to PV/SMV resection has been adopted. The present meta-analysis evaluated the perioperative outcomes and overall survival of patients undergoing pancreatic resection combined with PV/SMV vein resection compared with those patients without PV/SMV resection with the aim of evaluating feasibility and influence on patient outcomes. A systematic search was performed of PubMed, Embase, and the Cochrane Library in accordance with PRISMA guidelines from the time of inception to 2013. Inclusion criteria were comparative studies including patients who underwent pancreatic resection with or without PV/SMV resection. One-, 3-, and 5-year survival were the primary outcomes. Twenty-seven studies were identified involving a total of 9005 patients (1587 with PV/SMV resection). Patients undergoing PV/SMV resection had an increased risk of postoperative mortality (RD, 0.01; 95% CI, 0.00-0.03; P ¼ .02) and of R1/R2 resection (RD, 0.09; 95% CI, 0.06-0.13; P < .001) compared with those undergoing standard surgery. One-, 3-, and 5-year survival were worse in the PV/SMV resection group (HR, 1.23; 95% CI, 1.07-1.43; P ¼ .005), 1.48 (95% CI, 1.14-1.91; P ¼ .004) and 3.18 (95% CI, 1.95-5.19; P < .001) respectively. Median overall survival was 14.3 months for patients undergoing pancreatic resection with PV/ SMV resection and 19.5 months for those without vein resection (P ¼ .063). Comment: Two previous meta-analyses have showed similar perioperative outcomes and long term survival with pancreatic resections with PV/SMV resection and standard resection when an R0 resection was achieved. However, theoretically there is likely more advanced disease in the patients undergoing PV/SMV resection and the real issue is whether patients with PV/SMV tumor involvement who undergo PV/SMV resection will do better than those who were merely treated with adjuvant therapy alone or just pancreatic and biliary drainage. In the meantime, one can expect the trend for more aggressive resection of pancreatic cancer to continue as adjuvant therapy evolves and vascular and oncologic surgeons become more comfortable with PV/SMV resection and reconstruction.
Patency of the Viabahn Stent Graft for the Treatment of Outflow Stenosis in Hemodialysis Grafts Carmona J, Rits Y, Jones B, et al. Am J Surg 2016;211:551-4. Conclusions: Dialysis access grafts with outflow stenosis treated with Viabahn covered stents for the outflow stenosis have superior patency to arteriovenous grafts treated with angioplasty alone 12 months after treatment. Treatment results at earlier periods are comparable. Summary: Stenosis at the venous anastomosis is the most common reason for hemodialysis access graft malfunction and failure. Angioplasty and/or stent placement have been used for almost 2 decades as an option to treat these lesions to try and prolong the life of a dialysis access. A recent study indicated that stent grafts appeared to provide longer patency when used to treat venous anastomotic lesions of hemodialysis access graft compared to PTA alone (Vogel PM, J Vasc Interv Radiol 2005;16:1619-26). Covered stents therefore potentially make for prolonged functional patency of
hemodialysis access grafts and decreased morbidity of reintervention and ultimately less access abandonment. The purpose of this study was to evaluate arteriovenous graft (AVG) patency when failing grafts were treated with a Viabahn covered stent or PTA alone for outflow stenosis. This is a retrospective review of all patients undergoing endovascular interventions for failing grafts at a single institution between January 2010 and July 2013. Fortyfour patients were identified who were treated with PTA alone (n ¼ 11) and with Viabahn stent grafts (n ¼ 33) for stenosis at the vein to graft anastomosis. Patient demographics, procedural success, and intraoperative complications were recorded as well as graft patency at 3, 6, and 12 months. Graft patency was reviewed and compared with PTA alone. There were no statistically significant differences between the two groups regarding gender, prevalence of diabetes, hypertension, coronary artery disease, or peripheral arterial disease. Primary technical success, defined as a residual stenosis of #10%, was achieved in 100% of cases. Follow-up was determined by flow velocities during dialysis and with ultrasound imaging. At 12 months, 88% (29/33) of grafts with stents were functional vs 36.4 % (4/11) of those with PTA alone. Primary patency of the stent group was 61%, 52%, and 42% at 3, 6, and 12 months, respectively, vs 64%, 45%, and 9% in the PTA group. Comment: This was a small and nonrandomized retrospective study, but it does suggest that use of covered stents should perhaps be more widely considered for treatment of venous anastomosis stenosis in hemodialysis access grafts. Previous studies have not been able to consistently show a clear advantage of stent deployment to improve AV graft patency. The Viabahn stent, however, is heparin bonded, self-expanding and more flexible than previous stents employed and this may explain part of the benefit observed here. However, they are expensive, and before their use can be recommended widely, results here should be confirmed by larger, more rigorously designed studies.
Retinal Artery Occlusion and the Risk of Stroke Development: Twelve-Year Nationwide Cohort Study Rim TH, Han J, Choi YS, et al. Stroke 2016;47:376-82. Conclusions: Retinal artery occlusion (RAO) is significantly associated with subsequent stroke. Summary: RAO can lead to permanent vision loss. The retina is a component of the nervous system, as it is basically an extension of the diencephalon and originates from the neural tube, which is an embryologic part of the brain. RAO and stroke share a common pathophysiological mechanism of thromboembolism and common risk factors of hypertension, diabetes and hyperlipidemia (Hayreh SS, Prog Retin Eye Res 2005;24:493519). In the current study, the authors investigated possible association between RAO and subsequent risk of stroke occurrence based on cases of RAO and controls obtained from a nationwide representative sampling of 1,025,340 adults. The data were collected from the Korean National Health Insurance Service which comprised 1,025,340 random subjects. Patients with RAO were enrolled with initial diagnosis of either central or other RAO between January 2004 and December 2013 (n ¼ 401). The comparison group was composed of randomly selected subjects (five per RAO patient; n ¼ 2003) that were matched to the RAO group according to socio-demographic factors and year of RAO diagnosis. Each patient was tracked until 2013. Statistical analysis was by Cox proportional hazard regression. Stroke occurred in 15% of the RAO group and 8% of the comparison group (P < .001). RAO was associated with an increased risk of stroke occurrence (HR, 1.78; 95% CI, 1.32-2.41). The magnitude of RAO effect for stroke was larger among younger adults aged <65 years (HR, 3.11) than older adults aged $65 years (HR, 1.26). However, risk of subsequent stroke was significantly increased in older patients $65 years at the 4 year follow-up (HR, 1.58; 95% CI, 1.01-2.48). Comment: Central RAO is associated with visible emboli in <20% of people. Branch RAO has a higher rate of visible emboli approaching 60%-70% (Hayreh SS, Retina 2007;27:276-89, and Savino PJ et al, Arch Ophthalmol 1977;95:1185-9). A 2012 study from Taiwan reported similar results (Chang YS et al, Am J Ophthalmol 2012;154:645-52). Only 35% of ophthalmologists refer patients with central RAO to an emergency room (Atkins EJ et al, Am J Ophthalmol 2009;148:172-3); however, because
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