Effect of metabolic syndrome on the response to arterial injury

BACKGROUND

Metabolic syndrome is now an epidemic in the United States population. Intimal hyperplasia remains the principal lesion in the development of restenosis after vessel wall injury. The aim of this study is to characterize the changes induced in wall morphology in the developing intimal hyperplasia within a murine model in the presence of diabetes (type 1) and metabolic syndrome.

METHODS

Control (wild type B6), Non Obese Diabetic, and metabolic syndrome (RCS-10) mice were used. The murine femoral wire injury model was used in which a micro wire is passed through a branch of the femoral and used to denude the common femoral and iliac arteries. Specimens were perfusion fixed and sections were stained with hematoxylin and eosin and Movat stains such that dimensional and compositional morphometry could be performed using an ImagePro system. Additional stains for proliferation and apoptosis were used.

RESULTS

In control mice, the injured femoral arteries develop intimal hyperplasia, which is maximal at 28 d and remains stable to day 56. Sham-operated vessels do not produce such a response. In diabetic mice, the intimal response increased 5-fold with a 2-fold increase in proteoglycan deposition, whereas in the metabolic syndrome mice there was a 6-fold increase in the intimal response and a similar increase in proteoglycan deposition. Collagen deposition was different with a 22-fold increase over control in collagen deposition in diabetes and a 100-fold increase over control in collagen deposition in metabolic syndrome as compared with the control injury mice. Maximal vascular smooth muscle cell (VSMC) proliferation was decreased in both diabetes and metabolic syndrome compared with controls, whereas early cell apoptosis in both diabetes and metabolic syndrome was sustained over a longer period of time compared with wild-type mice.

CONCLUSIONS

These data demonstrate that development of intimal hyperplasia is markedly different in diabetes and metabolic syndrome compared with controls, with an increase in collagen deposition, a reduction in VSMC proliferation, and an increase in early VSMC apoptosis. These findings suggest that preventative strategies against restenosis must be tailored for the diabetic and metabolic syndrome patients.

Dissection of left iliac artery during anterior lumbar interspace fusion: Report of a case

Vascular injury is an uncommon complication of spine surgery. Among the different approaches, anterior lumbar interbody fusion has increased potential for vascular injuries, since the great vessels and their branches overly the disc spaces to be operated on, and retraction of these vessels is necessary to gain adequate surgical exposure. The reported incidence for anterior lumbar interbody fusion-associated vascular injuries ranges from 0% to 18.1%, with venous laceration as the most common type. We report a case of anterior lumbar interbody fusion-associated left common iliac artery dissection leading to delayed acute limb ischemia developing in early post-operative period.

Thrombocytopenia in Patients with Gastric Varices and the Effect of Balloon-occluded Retrograde Transvenous Obliteration on the Platelet Count

OBJECTIVES

Gastric varices primarily occur in cirrhotic patients with portal hypertension and splenomegaly and thus are probably associated with thrombocytopenia. However, the prevalence and severity of thrombocytopenia are unknown in this clinical setting. Moreover, one-third of patients after balloon-occluded retrograde transvenous obliteration (BRTO) have aggravated splenomegaly, which potentially may cause worsening thrombocytopenia. The aim of the study is to determine the prevalence and degree of thrombocytopenia in patients with gastric varices associated with gastrorenal shunts undergoing BRTO, to determine the prognostic factors of survival after BRTO (platelet count included), and to assess the effect of BRTO on platelet count over a 1-year period.

MATERIALS AND METHODS

This is a retrospective review of 35 patients who underwent BRTO (March 2008-August 2011). Pre- and post-BRTO platelet counts were noted. Potential predictors of bleeding and survival (age, gender, liver disease etiology, platelet count, model for end stage liver disease [MELD]-score, presence of ascites or hepatocellular carcinoma) were analyzed (multivariate analysis). A total of 91% (n = 32/35) of patients had thrombocytopenia (<150,000 platelet/cm(3)) pre-BRTO. Platelet counts at within 48-h, within 2 weeks and at 30-60 days intervals (up to 6 months) after BRTO were compared with the baseline pre-BRTO values.

RESULTS

35 Patients with adequate platelet follow-up were found. A total of 92% and 17% of patients had a platelet count of <150,000/cm(3) and <50,000/cm(3), respectively. There was a trend for transient worsening of thrombocytopenia immediately (<48 h) after BRTO, however, this was not statistically significant. Platelet count was not a predictor of post-BRTO rebleeding or patient survival. However, MELD-score, albumin, international normalized ratio (INR), and etiology were predictors of rebleeding.

CONCLUSION

Thrombocytopenia is very common (>90% of patients) in patients undergoing BRTO. However, BRTO (with occlusion of the gastrorenal shunt) has little effect on the platelet count. Long-term outcomes of BRTO for bleeding gastric varices using sodium tetradecyl sulfate in the USA are impressive with a 4-year variceal rebleed rate and transplant-free survival rate of 9% and 76%, respectively. Platelet count is not a predictor of higher rebleeding or patient survival after BRTO.

Endovascular techniques in limb salvage: cutting, cryo, brachy, and drug-eluting balloons

The complex pathophysiology response to injury of the lower-extremity arteries has prompted the development of several unique balloon technologies to overcome initial technical failures and short-term intimal hyperplasia. Cryoplasty alters the cellular and mechanical properties of the vessel wall during angioplasty. Cutting balloons incise the wall, preventing elastic recoil and allowing expansion of the lumen at a lower pressure, thus limiting barotrauma. Drug-eluting balloons actively transfer inhibitory compounds to the wall during the initial therapy, while brachytherapy balloons allow for localized delivery of radiation to inhibit the proliferative response seen after angioplasty. These platforms provide unique means to enhance immediate and short-term results and also reduce stent usage in the lower extremity.

Can endovascular therapy of infrainguinal disease for claudication be justified?

Traditionally, patients with exercise-induced lower extremity ischemia (claudicants) have been treated conservatively. It is important to remember that this is not because the pain of claudication is less important than pain due to other problems, but because the only 'cure', operative bypass, has been judged too invasive by both patient and physician. Recent data suggest that endovascular treatment of atherosclerotic disease below the inguinal ligament yields good short-term results, with low periprocedural morbidity and does not compromise future surgical alternatives in the long-term. If this approach is to be used as nonoperative treatment for the pain of claudication, however, the authors suggest that long-term success may be less important than the absolute minimization of short-term and periprocedural risk. The authors believe that given the results of modern endovascular therapy it is increasingly less acceptable to tell claudicants to live with their pain if conservative therapy fails. The option of endovascular treatment for infrainguinal atherosclerotic disease should be discussed with every patient whose claudication is significant, and considered as a treatment option in place of continued pain. This approach should be judged against conservative therapy for claudication, not against surgical bypass for limb threat.

Computational fluid dynamics investigation of chronic aortic dissection hemodynamics versus normal aorta

OBJECTIVES

To evaluate hemodynamic changes during aneurysmal dilatation in chronic type B aortic dissections compared to hemodynamic parameters in the healthy aorta with the use of computational fluid dynamics (CFD).

METHODS

True lumen (TL)/false lumen (FL) dimensional changes, changes in total pressure (TP), and wall shear stress (WSS) were evaluated at follow-up (FU) compared to initial examination (IE) with transient CFD simulation with geometries derived from clinical image data and inflow boundary conditions from magnetic resonance images. The TL/FL pressure gradient between ascending and descending aorta (DAo) and maximum WSS at the site of largest dilatation was compared to values for the healthy aorta.

RESULTS

Hemodynamic changes at site of largest FL dilatation included 77% WSS reduction and 69% TP reduction. Compared to the healthy aorta, pressure gradient between ascending and DAo was a factor of 1.4 higher in the TL and a factor of 1.5 in the FL and increased at FU (1.6 and 1.7, respectively). Maximum WSS at the site of largest dilatation was a factor of 3 lower than that for the healthy aorta at IE and decreased by more than a factor of 2 at FU.

CONCLUSIONS

The FL dilatation at FU favorably reduced TP. In contrast, unfavorable increase in pressure gradient between ascending and DAo was observed with higher values than in the healthy aorta. Maximum WSS was reduced at the site of largest dilation compared to healthy aorta.

Single-stage repair of a complex type B aortic dissection associated with a pressurized infrarenal abdominal aortic aneurysm

The decision-making involved in managing type 2 aortic dissections remains challenging despite the advances in endovascular technology. We report a challenging case of a patient presenting with a type 2 aortic dissection and false lumen extension into an infrarenal abdominal aortic aneurysm (AAA). Severe back pain and hypertension were the patient's initial complaints, and dynamic magnetic resonance angiography revealed 1-way pulsatile flow into the AAA sac from the false lumen. This patient underwent endovascular repair with a thoracic and infrarenal aortic endograft, successfully excluding the false lumen and decompressing the infrarenal aneursymal sac. This is a unique presentation of total endovascular repair of a symptomatic type B aortic dissection with a pressurized infrarenal AAA sac from false lumen flow into the sac.

Critical limb ischemia: reporting outcomes and quality

The impetus to pursue quality in limb salvage is high in the current economic environment. This has been spurred on by the diffusion of multiple technologies, the lack of well-defined cost-effectiveness benchmarks, and the paucity of process and structure benchmarks. Furthermore, no national database exists to capture current activity and trends, and lead structure and process changes that could analyze outcomes and improve standards in peripheral interventions for limb salvage. This manuscript examines the challenges in measuring outcomes and quality in limb salvage and explores the components necessary for ensuring quality in limb salvage interventions.

The Effect of Balloon-Occluded Transvenous Obliteration of Gastric Varices and Gastrorenal Shunts on the Hepatic Synthetic Function

Purpose:

To evaluate the effect of balloon-occluded transvenous obliteration (BRTO) on the model for end-stage liver disease (MELD) and the Child-Pugh (C-P) score and their individual components.

Methods:

A retrospective review of patients undergoing only BRTO without transjugular intrahepatic portosystemic shunt was performed (08, 2007 to 06, 2010). Pre- and post-BRTO MELD and C-P scores were calculated. The post-BRTO MELD and C-P score samplings were categorized as (1) immediate (within 14 days), (2) early (14-90 days), and (3) delayed (90-180 days) post-BRTO. The C-P and MELD scores and their individual components before and after (various sample intervals) were compared.

Results:

A total of 29 consecutive successful BRTO procedures were found and assessed. In all, 26 had immediate post-BRTO sampling (average 1.8 days after BRTO), 13 (57%) had an early post-BRTO sampling (average 47 days from BRTO), and 10 (38%) had a delayed post-BRTO sampling (average 121 days from BRTO). The bilirubin rises significantly ( P = .007) within days after BRTO, but synthetic function improves significantly between 1.5 and 4.0 months post-BRTO (international normalized ration: P = .02, bilirubin: P = .027, and albumin: P = .012). However, 31% (N = 8/ 26) of the patients had worsening ascites with or without hydrothorax. The MELD score significantly improved circa 4 months post-BRTO (from 14.1 to 10.7, P = .0008). However, the C-P score did not change significantly (from 7.6 to 6.7, P = .063).

Conclusion:

The BRTO has a positive effect on the hepatic synthetic function. However, there is a high incidence of post-BRTO ascites (31% of the patients). As a result, the MELD score appears to be a more sensitive gauge for hepatic synthetic function compared to the C-P score for patients undergoing BRTO.

End-stage renal disease and limb salvage

The prevalence of peripheral arterial disease and both traditional and nontraditional vascular risk factors are more common in patients with end-stage renal disease who are undergoing hemodialysis than the general population. Patients undergoing hemodialysis may also be at risk for peripheral arterial disease via nonvascular risk factors and the hemodialysis treatment itself. Unfortunately, because peripheral arterial disease and its risk factors in hemodialysis patients have not been thoroughly ascertained, evaluation of potential treatments has been limited. Given the high potential of morbidity and impaired quality-of-life related to peripheral arterial disease in patients with end-stage renal disease, additional studies are needed to evaluate both quality of life and potential screening for peripheral arterial disease, its risk factors, and treatments to identify areas for improvement in this vulnerable population.

Prophylactic distal revascularization and interval ligation procedure during femoral vein transposition fistula creation in patients at high risk for ischemic complications

Femoral vein transposition arteriovenous fistula (FVt AVF) is a viable autologous option when upper extremity dialysis access sites have become compromised. High volume flow through the AVF can lead to ischemic complications, including steal syndrome (SS), and may threaten access and limb viability. Risk factors for SS include: age >60 years, female sex, diabetes, atherosclerosis, hypertension, and previous limb procedures. Two dialysis patients, who were at high risk for SS in their lower extremities as assessed during the preoperative evaluation for an elective FVt AVF, had a distal revascularization and interval ligation (DRIL) procedure concurrently performed. At 42 and 24 months from their respective surgeries, both patients are reliably using their lower extremity autologous access sites and have not developed any signs or symptoms of ischemia. DRIL may represent an effective surgical strategy that can prophylactically be used to minimize the incidence of ischemic complications during FVt AVF in carefully selected, high-risk patients.