Adnan Z. Rizvi

The effect of left subclavian artery coverage on morbidity and mortality in patients undergoing endovascular thoracic aortic interventions: A systematic review and meta-analysis

OBJECTIVES Thoracic endografts (stent grafts) have emerged as a less invasive modality to treat various thoracic aortic lesions. The intentional coverage of the left subclavian artery (LSA) during the placement of these endografts is associated with several complications including stroke, spinal cord ischemia, and arm ischemia. In this review, we synthesize the available evidence regarding the complications associated with LSA coverage. METHODS We searched electronic databases (MEDLINE and EMBASE) from January 1990 through February 2008 for studies that included patients who received thoracic endografts and had intentional LSA coverage. Eligible studies had a control group that either received the endograft without LSA coverage or had primary revascularization prior to coverage. Two independent reviewers determined trial eligibility and extracted descriptive, methodological and outcome data from each eligible study. Meta-analyses estimated Peto odds ratio (OR) and 95% confidence intervals (CI) to describe the strength of association between coverage and complications; the I(2) statistic described the proportion of inconsistency of treatment effect among studies not due to chance. RESULTS We found 51 eligible observational studies. LSA coverage was associated with significant increase in the risk of arm ischemia (OR 47.7; CI, 9.9-229.3; I(2) = 72%, 19 studies) and vertebrobasilar ischemia (OR 10.8; CI, 3.17-36.7; I(2) = 0%; eight studies); and nonsignificant increase in the risk of spinal cord ischemia (OR 2.69; CI, 0.75-9.68; I(2) = 40%; eight studies) and anterior circulation stroke (OR 2.58; CI, 0.82-8.09; I(2) = 64%, 13 studies). There were no significant associations between LSA coverage and death, myocardial infarction, or transient ischemic attacks. The incidence of phrenic nerve injury as a complication of primary revascularization was 4.40% (CI, 1.60%-12.20%). Data on perioperative infection were sparse and rarely reported. CONCLUSIONS Very low quality evidence suggests that LSA coverage increases the risk of arm ischemia, vertebrobasilar ischemia, and possibly spinal cord ischemia and anterior circulation stroke.

Benign superior vena cava syndrome: Stenting is now the first line of treatment

BACKGROUND Endovascular repair (EVR) is emerging as first-line treatment for patients with superior vena cava (SVC) syndrome of benign etiology, but data on its durability remain scarce. The aims of this study were to assess the efficacy and durability of EVR and compare results of EVR with open surgical reconstruction (OSR). METHODS Data from 70 consecutive patients undergoing treatment for benign SVC syndrome between November 1983 and November 2006 were retrospectively reviewed. RESULTS There were 30 males and 40 females (mean age, 41 years; range, 5-75 years). Etiology included indwelling catheters or pacemaker wires in 35 patients, mediastinal fibrosis in 31, idiopathic thrombosis in 2, hypercoagulable disorder in 1, and postsurgical thrombosis in 1. In 42 patients, OSR was done through a median sternotomy: repair was with spiral saphenous vein in 22, expanded polytetrafluoroethylene (ePTFE) in 13, femoral vein grafts in 6, and human allograft in 1. Fifteen OSRs followed failed EVR interventions. EVR was attempted in 32 patients and was successful in 28 (88%): 19 had stenting, 14 had percutaneous transluminal balloon angioplasty (PTA), 2 had thrombolytic therapy with PTA, and 3 had stenting. All four technical failures subsequently underwent OSR. There were no early deaths in either group. Periprocedural morbidity was 19% after OSR and 4% in the EVR group. Six early surgical graft failures were successfully treated with surgical revision; one restenosis after EVR was restented. During a mean follow-up of 4.1 years (range, 0.1-17.5 years) after OSR, 11 patients underwent 18 secondary interventions. Mean follow-up after EVR was 2.2 years (range, 0.2-6.4 years), and nine patients underwent 21 secondary EVR interventions. Primary, assisted primary, and secondary patency rates of surgical bypass grafts were, respectively, 45%, 68%, and 75% at 3 and 5 years. Primary, assisted primary and secondary patency rates after EVR were 44%, 96%, and 96% at 3 years. Assisted primary patency was significantly higher in vein grafts than in ePTFE grafts (P = .05). Assisted primary and secondary patency was significantly higher in patients undergoing stenting compared with PTA (P = .02). At last follow-up, 93% of patients in both OSR and EVR groups had significant relief from symptoms. CONCLUSIONS OSR of benign SVC syndrome is effective, with durable long-term relief from symptoms. EVR is less invasive but equally effective in the mid-term, albeit at the cost of multiple secondary interventions, and is an appropriate primary treatment for benign SVC syndrome. OSR remains an excellent choice for patients who are not suitable for EVR or in whom the EVR fails.

Comparative effectiveness of the treatments for thoracic aortic transaction

OBJECTIVES To synthesize the available evidence regarding the outcomes associated with nonoperative management, open repair, and endovascular repair of thoracic aortic transection. METHODS We searched electronic databases (MEDLINE, EMBASE Cochrane, Web of Science, and Scopus) for studies that enrolled patients with aortic transection and measured the outcomes of interest. Two reviewers determined study eligibility and extracted data. We estimated the event rate associated with the different approaches from case series and the relative risk from comparative studies. Estimates from each study were pooled using the random effects model. RESULTS We found 139 studies that fulfilled the inclusion criteria, the majority of which were noncomparative surgical case series, retrospective, and none were randomized. Studies included 7768 patients, the majority of which were males. The mortality rate was significantly lower in patients who underwent endovascular repair, followed by open repair and nonoperative management (9%, 19%, and 46%, respectively, P < .01). No significant difference in event rate across the three groups was noted for the outcomes of anterior stroke, posterior stroke, or any stroke. The risk of spinal cord ischemia and end-stage renal disease were higher in open repair compared with the other 2 groups (9% vs 3% and 3%, P = .01 for spinal cord ischemia and 8% vs 5% and 3%, P = .01 for end-stage renal disease). Compared with endovascular repair, open repair was associated with an increased risk of graft infection and systemic infections. Meta-analyses of comparative studies demonstrated that compared with open repair, endovascular repair is associated with reduced mortality and spinal cord ischemia (relative risk, 0.61; 95% confidence interval, 0.46-0.80; and relative risk, 0.34; 95% confidence interval, 0.16-0.74; respectively). Inferences are limited by methodological quality, survival, and publication biases. CONCLUSIONS Very low-quality evidence suggests that, compared with open repair or nonoperative management, endovascular repair of thoracic aortic transection is associated with better survival and decreased risk of spinal cord ischemia, renal injury, and graft and systemic infections. Nonoperative management is associated with the least favorable outcomes.

Autogenous versus prosthetic vascular access for hemodialysis: a systematic review and meta-analysis.

OBJECTIVES The autogenous arteriovenous access for chronic hemodialysis is recommended over the prosthetic access because of its longer lifespan. However, more than half of the United States dialysis patients receive a prosthetic access. We conducted a systematic review to summarize the best available evidence comparing the two accesses types in terms of patient-important outcomes. METHODS We searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science and SCOPUS) and included randomized controlled trials and controlled cohort studies. We pooled data for each outcome using a random effects model to estimate the relative risk (RR) and its associated 95% confidence interval (CI). We estimated inconsistency caused by true differences between studies using the I(2) statistic. RESULTS Eighty-three studies, of which 80 were nonrandomized, met eligibility criteria. Compared with the prosthetic access, the autogenous access was associated with a significant reduction in the risk of death (RR, 0.76; 95% CI, 0.67-0.86; I(2) = 48%, 27 studies) and access infection (RR, 0.18; 95% CI, 0.11-0.31; I(2) = 93%, 43 studies), and a nonsignificant reduction in the risk of postoperative complications (hematoma, bleeding, pseudoaneurysm and steal syndrome, RR 0.73; 95% CI, 0.48-1.16; I(2) = 65%, 31 studies) and length of hospitalization (pooled weighted mean difference -3.8 days; 95% CI, -7.8 to 0.2; P = .06). The autogenous access also had better primary and secondary patency at 12 and 36 months. CONCLUSION Low-quality evidence from inconsistent studies with limited protection against bias shows that autogenous access for chronic hemodialysis is superior to prosthetic access.

Left subclavian artery revascularization: Society for Vascular Surgery ® Practice Guidelines

The use of thoracic stent grafts to manage patients with various aortic pathologies is a rapidly expanding area in the field of vascular surgery. It has supplanted traditional open surgery in the treatment of many specific aortic diseases, including descending thoracic aneurysms, acute complicated dissection, traumatic transection, and penetrating ulcers. Because of the need for an adequate proximal seal zone and limitations of current technology of stent grafts, the left subclavian artery (LSA) may need to be covered in 26% to 40% of patients undergoing thoracic endovascular aortic repair (TEVAR). 1,2 In the first United States regulatory trial, 3 all patients were required to undergo prophylactic LSA revascularization before TEVAR if the LSA was covered, but this practice has not become predominant in clinical practice. There is great variability amongst surgeons and interventionalists about which patient undergoes LSA revascularization before TEVAR. Some surgeons perform routine LSA revascularization, whereas others are selective, such as in cases of a left vertebral artery ending at the posterior inferior cerebellar artery, a prior left internal mammary-to-coronary artery bypass, or an absent distal right vertebral artery. Lastly, some surgeons only perform LSA revascularization if symptoms of left arm ischemia or subclavian steal syndrome occur after TEVAR. 1,4,5 Unfortunately, most of the data about LSA coverage during TEVAR and the morbidity and mortality associated with this come from single institutional series or registries, thus the current management of the LSA when coverage is necessary is not uniform. The Society for Vascular Surgery ® (SVS) recently formed a Committee on Aortic Disease to formulate clinical practice guidelines to aid physicians and patients regarding LSA revascularization during TEVAR. A third-party, the Knowledge and Encounter Research Unit, Mayo Clinic, Rochester, performed a comprehensive literature review and formulated a systematic review and meta-analysis relating the effect of LSA coverage on the morbidity and mortality of patients undergoing TEVAR. 6 The SVS used this review and the consensus of the committee to develop three recommendations regarding LSA revascularization in relationship to TEVAR. 7 This article reviews the potential complications associated with LSA coverage and summarizes the SVS Practice Guidelines in the management of the LSA during TEVAR.

Surveillance of arteriovenous hemodialysis access: A systematic review and meta-analysis

OBJECTIVES Hemodialysis centers regularly survey arteriovenous (AV) accesses for signs of dysfunction. In this review, we synthesize the available evidence to determine to what extent proactive vascular access monitoring affects the incidence of AV access thrombosis and abandonment compared with clinical monitoring. METHODS We searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science, and SCOPUS) and sought references from experts, bibliographies of included trials, and articles that cited included studies. Two reviewers independently assessed trial quality and extracted data. We used random effects meta-analysis to estimate the pooled relative risk (RR) and 95% confidence interval (CI) across studies and conducted subgroup analyses to explain heterogeneity. The I(2) statistic was used to assess heterogeneity of treatment effect among trials. RESULTS Nine studies (1363 patients) compared a strategy of surveillance vs clinical monitoring. A vascular intervention to maintain or restore patency was provided to both groups if needed. Surveillance followed by intervention led to a nonsignificant reduction of the risk of access thrombosis (RR, 0.82; 95% CI, 0.58-1.16; I(2) = 37%) and access abandonment (RR, 0.80; 95% CI, 0.51-1.25; I(2) = 60%). Three studies (207 patients) compared the effect of vascular interventions vs observation in patients with abnormal surveillance result. Vascular interventions after an abnormal AV access surveillance led to a significant reduction of the risk of access thrombosis (RR, 0.53; 95% CI, 0.36-0.76) and a nonsignificant reduction of the risk of access abandonment (RR, 0.76; 95% CI, 0.43-1.37). CONCLUSION Very low quality evidence yielding imprecise results suggests a potentially beneficial effect of AV access surveillance followed by interventions to restore patency. This inference, however, is weak and will require randomized trials of AV access surveillance vs clinical monitoring for rejection or confirmation.

The contemporary management of renal artery aneurysms

BACKGROUND Renal artery aneurysms (RAAs) are rare, with little known about their natural history and growth rate or their optimal management. The specific objectives of this study were to (1) define the clinical features of RAAs, including the precise growth rate and risk of rupture, (2) examine the current management and outcomes of RAA treatment using existing guidelines, and (3) examine the appropriateness of current criteria for repair of asymptomatic RAAs. METHODS A standardized, multi-institutional approach was used to evaluate patients with RAAs at institutions from all regions of the United States. Patient demographics, aneurysm characteristics, aneurysm imaging, conservative and operative management, postoperative complications, and follow-up data were collected. RESULTS A total of 865 RAAs in 760 patients were identified at 16 institutions. Of these, 75% were asymptomatic; symptomatic patients had difficult-to-control hypertension (10%), flank pain (6%), hematuria (4%), and abdominal pain (2%). The RAAs had a mean maximum diameter of 1.5 ± 0.1 cm. Most were unilateral (96%), on the right side (61%), saccular (87%), and calcified (56%). Elective repair was performed in 213 patients with 241 RAAs, usually for symptoms or size >2 cm; the remaining 547 patients with 624 RAAs were observed. Major operative complications occurred in 10%, including multisystem organ failure, myocardial infarction, and renal failure requiring dialysis. RAA repair for difficult-to-control hypertension cured 32% of patients and improved it in 26%. Three patients had ruptured RAA; all were transferred from other hospitals and underwent emergency repair, with no deaths. Conservatively treated patients were monitored for a mean of 49 months, with no acute complications. Aneurysm growth rate was 0.086 cm/y, with no difference between calcified and noncalcified aneurysms. CONCLUSIONS This large, contemporary, multi-institutional study demonstrated that asymptomatic RAAs rarely rupture (even when >2 cm), growth rate is 0.086 ± 0.08 cm/y, and calcification does not protect against enlargement. RAA open repair is associated with significant minor morbidity, but rarely a major morbidity or mortality. Aneurysm repair cured or improved hypertension in >50% of patients whose RAA was identified during the workup for difficult-to-control hypertension.

Timing of referral for vascular access placement: a systematic review.

OBJECTIVE This review was conducted to determine the optimal timing for referring patients with end-stage renal disease to vascular surgery for access placement. METHODS A systematic review of the electronic databases (MEDLINE, EMBASE, Current Contents, Cochrane CENTRAL and Web of Science) was conducted through March 2007. Randomized and observational studies were eligible if they compared an early referral cohort with a late referral cohort in terms of patient-important outcomes such as death, access-related sepsis, and hospitalization related to access complications. RESULTS We found no studies that fulfilled eligibility criteria. CONCLUSION At the present time, the optimal timing for referral to vascular surgery for vascular access placement is based on expert opinion and choices made by patients and physicians.

The Success and Safety of Endovenous Ablation in Patients With Previous Superficial Venous Thrombosis A Retrospective Case–Control Study

Objectives: Retrospective case–control study to determine the failure and endovenous heat-induced thrombosis (EHIT) rates of endovenous ablation (EVA) in patients with a history of superficial venous thrombosis (SVT). Methods: Study and control groups each consisted of 73 patients with or without the history of SVT, who underwent EVA between June 2010 and July 2012. All patients were followed with venous duplex ultrasound. Procedural failure and EHIT rates were considered primary outcomes. Results: There was no difference in EHIT or failure rates between study and control groups (P = 1.00). There was no difference in EHIT or failure rates between patients with and without the history of venous thromboembolism (VTE), with and without the history of VTE and/or SVT, with and without the history of thrombophilia, and on and off anticoagulation for either group or the combined study population. For the combined study population, failure rate was higher in patients with a history of VTE. Conclusions: Although EVA seems to be safe and effective in patients with a history of SVT, vein access in this patient group might require multiple attempts.