Wayne W. Zhang

Experience with a new negative pressure incision management system in prevention of groin wound infection in vascular surgery patients

OBJECTIVE Groin wound infection is an important cause of postoperative morbidity in vascular surgery patients, especially when prosthetic grafts are involved. The objective of this study was to investigate if Prevena (Kinetic Concepts, Inc, San Antonio, Tex), a negative pressure incision management system, could reduce the risk of groin wound infection in patients after vascular surgery. METHODS Ninety patients (115 groin incisions) underwent longitudinal or transverse femoral cutdown for vascular procedures. A retrospective chart review was performed on 63 consecutive incisions in patients in the non-Prevena group from December 2009 to November 2010 and on 52 consecutive incisions in patients in the Prevena group from January 2011 to December 2011. Prevena was applied intraoperatively and removed 5 to 7 days postoperatively. The non-Prevena group received either a skin adhesive or absorbent dressing. Groin incisions were assessed, and infection was graded based on Szilagyi classifications. Student t-test and two-sample proportion z test were used for statistical analyses. A P value < .05 was considered statistically significant. RESULTS Comorbidities and known risk factors for infection were compared; there were no statistically significant differences between the two groups. Prosthetic material was used in 34 (65%) incisions in the Prevena group and 29 (46%) incisions in the non-Prevena group. Fifty (96%) incisions within the Prevena group and 60 (96%) in the non-Prevena group were classified as clean surgical wounds. Wounds were evaluated at 7 days and 30 days postoperatively. Of 63 groin incisions in 49 patients in the non-Prevena group, 19 (30%) incisions had groin wound infections. Wound infections were classified into Szilagyi grade I (10; 16%), Szilagyi grade II (7; 11%), and Szilagyi grade III (2; 3%). Of 52 groin incisions in 41 patients in the Prevena group, three (6%) incisions had Szilagyi grade I wound infections. No grade II or III infections occurred in this group. Overall incidence of infection between the two groups was statistically significant (P = .0011). CONCLUSIONS In this clinical study, Prevena negative pressure dressing significantly decreased the incidence of groin wound infection in patients after vascular surgery.

Warfarin anticoagulation before angioplasty relieves thrombus burden in Budd-Chiari syndrome caused by inferior vena cava anatomic obstruction

OBJECTIVES Pulmonary embolism (PE) is one of the major complications after percutaneous balloon angioplasty (PTBA) for Budd-Chiaris syndrome (BCS). The purpose of this study was to investigate the role of warfarin pre-treatment in the prevention of PE after PTBA in patients with large inferior vena cava (IVC) thrombus. PATIENTS AND METHODS From October 2002 to December 2009, 16 patients with symptomatic membranous or segmental IVC occlusion and large thrombus were treated with warfarin before PTBA. Eleven patients were men and 5 were women. The median age was 36 years, ranging from 21 to 52 years. The median duration of warfarin treatment before PTBA was 7 months, ranging from 3 to 12 months. Fourteen patients had membranous IVC occlusion and 2 had segmental occlusion. All 16 patients had significant thrombi underneath the obstructive lesions. PE diagnosis was based on clinical presentation and pulmonary computerized tomographic angiogram, if indicated. RESULTS In 14 of 16 patients, IVC thrombus was completely or near-completely resolved based on follow-up cavogram and PTBA was performed. In the other 2 patients, residual thrombus was demonstrated by cavogram at 12 months. PTBA and stent placement were carried out. IVC patency in the 16 patients was confirmed by completion cavogram. No major bleeding complication during warfarin pre-treatment aimed to keep international normalized ratio (INR) 2 to 3. There was no clinically significant PE or death in this group during follow-up, ranging from 6 to 40 months (median 21 months). CONCLUSION Spontaneous fibrinolysis of IVC thrombus occurs within 1 year in the majority of the patients treated with warfarin. Pre-treatment with warfarin prevents PE after PTBA in the patients with BCS with IVC membranous or segmental occlusion and large thrombus.

Blood transfusion is associated with increased risk of perioperative complications and prolonged hospital duration of stay among patients undergoing amputation

OBJECTIVE We evaluated the outcomes of patients undergoing major lower-extremity amputation who received packed red blood cell transfusion. METHODS Using the dataset of the National Surgical Quality Improvement Program (2005-2011), we examined 5,739 above-knee and 6,725 below-knee amputations. Patients were stratified by perioperative (preoperative, intraoperative, or postoperative) blood transfusion. Outcomes included perioperative mortality, myocardial infarction (MI), thromboembolism, and duration of stay (DOS) at the hospital. Adjusted comparisons of outcomes between transfused and not-transfused patients were performed by matching the 2 groups for age, smoking, diabetes, renal failure, coronary artery disease, classification of the American Society of Anesthesiologists, functional status, and procedure type. Multivariable logistic and gamma regression were used to examine associations between transfusion and outcomes. RESULTS Of the 12,464 amputations in the study cohort 2,133 (17%) required transfusion. The majority of the cases were performed for critical limb ischemia (8,205 amputations; 66%) and the overall 30-days mortality was 9%. In both crude and matched cohorts, although perioperative mortality and cardiac complication rates were similar, transfusion was associated with a greater incidence of pneumonia (crude: 6.1% vs 3%, P < .001; matched: 5.9% vs 3.7%, P < .001), thromboembolism (2.5% vs 1.6%, P = .003; 2.5% vs 1.4%, P = .002) and longer DOS (18 ± 19 vs 13.6 ± 14.3 days, P < .001; 17.8 ± 18.4 vs 14.2 ± 14.5 days, P < .001). Multivariable adjustment for confounding variables in the crude cohort demonstrated that transfusion was independently associated with a greater odds of perioperative pneumonia (odds ratio [OR]:1.6; 95% confidence interval [CI]:1.3-2; P < .001), thromboembolism (OR 1.3, 95% CI 1.0-1.9, P = .09) and longer DOS (mean ratio: 1.1; 95% CI 1.1-1.6; P = .006). CONCLUSION Among patients who had major lower-extremity amputation, perioperative transfusion independently predicted greater risks for perioperative pneumonia, thromboembolism, and prolonged hospital DOS.

Surgical and endovascular treatment of severe complications secondary to noncirrhotic portal hypertension: experience of 56 cases.

BACKGROUND Major complications of noncirrhotic portal hypertension (NCPH) include bleeding esophagogastric varices, hypersplenism, ascites, and bowel ischemia under acute circumstances. The aim of this article is to determine the outcomes of surgical and endovascular treatments for severe complications from NCPH. METHODS From January 2000 to June 2011, 56 patients with symptomatic NCPH underwent open surgery or endovascular thrombolysis. The medical records were retrospectively reviewed. Of the 56 patients, there were 39 males and 17 females. The mean age was 21 years, ranging from 2 to 54 years. Forty-one of them were diagnosed to have prehepatic portal vein obstruction (PHPVO), 9 had Budd-Chiari syndrome (BCS), and 6 had noncirrhotic portal fibrosis (NCPF). All patients were symptomatic from 5 days to 14 years (mean 25 months). Portosystemic shunt (PSS) was primarily performed in 49 patients. Shunts were as follows: 35 mesocaval; 7 splenorenal; 4 portocaval; 2 paraumbilical-jugular; and 1 portal to right atrial. Esophagogastric devascularization was performed in 3 patients, but was converted to mesocaval shunt later in 2. The remaining 4 patients with acute superior mesenteric vein (SMV) and portal vein thrombosis were treated with endovascular catheter-directed thrombolysis. Warfarin was prescribed to all the patients for at least 6 months. Mean follow-up was 57 months, ranging from 2 to 125 months. The outcomes, focusing on 30-day mortality, recurrent bleeding, and hypersplenism, were recorded. RESULTS In the 49 patients undergoing primary PSS, the shunts remained patent and there was no recurrent variceal bleeding during the follow-up. All 3 patients with esophagogastric devascularization had recurrent variceal bleeding at 8, 13, and 24 months postoperatively. Two of them were converted to mesocaval shunt, and 1 died before redo operation. Thrombolysis in all 4 patients with acute SMV and portal thrombosis was technically successful. Three of the 4 survived without complications and 1 died from small bowel infarction due to recurrent thrombosis 40 days later. In the 47 patients with hypersplenism, mean platelet counts increased from 43×10(9)/L to 239×10(9)/L 2 weeks after surgery. Ascites in 30 of the 31 patients disappeared within 2 months after PSS. There was no postoperative encephalopathy, and perioperative 30-day mortality was 0%. CONCLUSIONS PSS can be employed to treat bleeding esophagogastric varices and severe hypersplenism secondary to NCPH. Post-PSS encephalopathy is less of a concern in NCPH patients with normal liver function. Endovascular catheter-directed thrombolysis via superior mesenteric artery is a useful alternative treatment for acute portal and/or mesenteric venous thrombosis.

Physician modification of Gore C3 excluder endograft for treatment of abdominal aortic aneurysms anatomically unsuitable for conventional endovascular repair.

Until recently, the Cook Zenith aortic endograft (Cook Medical Inc, Bloomington, Ind) was the only device used for physician-modified fenestration because its constraining wire allowed physicians to reconstrain the device after modifications. Although the Cook Zenith fenestrated endograft has been approved by the Food and Drug Administration, it is currently not available in the majority of the hospitals and is not applicable to the patients who need urgent or emergent aneurysm repair. With the redesign of the Gore C3 delivery system, the Gore Excluder aortic stent graft (W. L. Gore & Associates, Inc, Flagstaff, Ariz) can now also be reconstrained, which makes it suitable for physician-modified fenestration. We describe the technique for modification and implantation of the Gore Excluder aortic stent graft in a patient requiring 2-vessel bilateral renal artery fenestration. This application provides an additional option for treatment of patients with abdominal aortic aneurysms who are anatomically unsuitable for conventional endovascular aneurysm repair and are at high risk for open repair.

Atrial Natriuretic Peptide Protects Against Ischemia-Reperfusion Injury in Rabbit Hearts In Vivo:

The aim of this study is to investigate whether atrial natriuretic peptide can mimic preconditioning to protect ischemia or reperfusion injury in rabbit hearts. New Zealand white rabbits were randomized into 3 groups: (1) Controls. Hearts received a 60 minute-occlusion of the left anterior descending artery, followed by a 180 minute-reperfusion. (2) Preconditioning. Two 5-minute periods of ischemia separated by a 10-minute reperfusion, followed by a 60-minute ischemia and a 180-minute reperfusion. (3) Atrial natriuretic peptide treatment. Bolus injection of exogenous atrial natriuretic peptide (2.5 µg/kg) given intravenously at 15 minutes prior to 60 minute-ischemia followed by a 180-minute reperfusion. Myocardial necrotic area and area at risk of necrosis were determined by triphenyltetrazolium chloride staining. Ratio of necrotic area to area at risk was 49.95% ± 1.15%, 7.95% ± 0.33%, and 8.36% ± 0.61% in the controls, preconditioning group, and atrial natriuretic peptide group, respectively. Both preconditioning and atrial natriuretic peptide significantly reduced the size of infarct caused by ischemia (preconditioning vs controls, P < .05; atrial natriuretic peptide vs controls, P < .05). Atrial natriuretic peptide can mimic ischemic preconditioning to protect rabbit hearts from prolonged ischemia and reperfusion injury. It may be involved in the cardioprotective mechanisms of preconditioning.

Optimal management of infrainguinal arterial occlusive disease

Peripheral arterial occlusive disease is becoming a major health problem in Western societies as the population continues to age. In addition to risk of limb loss, the complexity of the disease is magnified by its intimate association with medical comorbidity, especially cardiovascular and cerebrovascular disease. Risk factor modification and antiplatelet therapy are essential to improve long-term survival. Surgical intervention is indicated for intermittent claudication when a patient’s quality of life remains unacceptable after a trial of conservative therapy. Open reconstruction and endovascular revascularization are cornerstone for limb salvage in patients with critical limb ischemia. Recent advances in catheter-based technology have made endovascular intervention the preferred treatment approach for infrainguinal disease in many cases. Nevertheless, lower extremity bypass remains an important treatment strategy, especially for reasonable risk patients with a suitable bypass conduit. In this review, we present a summary of current knowledge about peripheral arterial disease followed by a review of current, evidence-based medical and surgical therapy for infrainguinal arterial occlusive disease.

Carvedilol promotes mitochondrial biogenesis by regulating the PGC-1/TFAM pathway in human umbilical vein endothelial cells (HUVECs).

Carvedilol, a third-generation and nonselective β-adrenoceptor antagonist, is a licensed drug for treating patients suffering from heart failure in clinics. It has been shown that Carvedilol protects cells against mitochondrial dysfunction. However, its unknown whether Carvedilol affects mitochondrial biogenesis. In this study, we found that treatment with Carvedilol in HUVECs resulted in a significant increase of PGC-1α, NRF1, and TFAM. Notably, Carvedilol significantly increased mtDNA contents and the two mitochondrial proteins, cytochrome C and COX IV. In addition, MitoTracker Red staining results indicated that treatment with Carvedilol increased mitochondria mass. Mechanistically, we found that the effect of Carvedilol on the expression of PGC-1α is mediated by the PKA-CREB pathway. Importantly, our results revealed that stimulation of mitochondrial biogenesis by carvedilol resulted in functional gain of the mitochondria by showing increased oxygen consumption and mitochondrial respiratory rate. The increased expression of PGC-1α and mitochondrial biogenesis induced by Carvedilol might suggest a new mechanism of the therapeutic effects of Carvedilol in heart failure.

Hybrid Repair of Ruptured Type B Aortic Dissection Extending into an Aberrant Right Subclavian Artery in a Patient With Turner's Syndrome

Turners syndrome (TS) has been documented as the most common cause of aortic dissection in young women. However, little attention from vascular surgery has been paid to these patients. We report the first case of ruptured type B aortic dissection with aberrant right subclavian artery treated successfully with hybrid endovascular and open procedures in a patient with TS. Left carotid to subclavian artery bypass, thoracic endovascular aortic repair, and coil embolization of the aberrant right subclavian and left subclavian arteries were performed in an emergency setting. Literature on epidemiology, causes, and management options of acute aortic dissection in TS patients are reviewed and discussed.

Accuracy of digital subtraction angiography, computed tomography angiography, and magnetic resonance angiography in grading of carotid artery stenosis in comparison with actual measurement in an in vitro model.

BACKGROUND The aim of this study was to investigate the accuracy of digital subtraction angiography (DSA), computed tomography angiography (CTA), and magnetic resonance angiography (MRA) in grading of carotid stenosis compared with actual measurement in an in vitro model. METHODS Various grades of stenosis were created by adhering different amounts of silicone rubber sealant onto the inner wall of clear, radiolucent tubes. After DSA, CTA, and MRA, the tubes were transected with 1-mm interval through the plaques. The cross-sectional areas were digitally photographed, and the percentage of area reduction of every single slide was measured with ImageJ planimetric software. The maximum actual area reduction (AAR) stenosis of each tube was recorded. The differences among DSA, CTA, MRA, and AAR were compared statistically using paired Student t test. RESULTS Overall, CTA and MRA significantly underestimated the degrees of stenosis compared with AAR (P = 0.001 and P = 0.0009, respectively), and no significant difference was found between DSA and AAR (P = 0.40). In the subgroup with stenosis of <70%, there was no significant difference between DSA, CTA, and MRA versus AAR (P = 0.18, P = 0.16, and P = 0.08, respectively). In the subgroup with severe stenosis of >70%, CTA and MRA significantly underestimated the stenosis versus AAR (P = 0.004, and P = 0.007 respectively), and DSA significantly overestimated the stenosis (P = 0.0007). CONCLUSIONS This in vitro model study demonstrated that CTA and MRA underestimate the lesions in severe stenosis of >70%. DSA tends to overestimate the disease. The accuracy of DSA is affected by plaque morphology, such as mountain-shaped lesions.