Mobility Rates After Lower-Limb Amputation for Patients Treated with Physician-Led Collaborative Care Model

BACKGROUND

Clinical outcomes after major lower-limb amputation have been historically poor. The current care provided to most amputees is often disorganized and without physician supervision. The primary purpose of this study is to examine rates of postamputation mobility achieved with a prosthesis by patients with chronic limb-threatening ischemia and/or diabetes who required major lower-limb amputation and were treated under an established physician-led collaborative care pathway. The secondary purpose is to describe the structure and utilization of the care pathway by multiple independent vascular surgery practices in the United States to enable future exploration of its impact on key clinical outcomes within this patient population.

METHODS

Clinical records of 2,475 patients from 6 vascular practices that adopted this collaborative care pathway between 2017 and 2020 were retrospectively reviewed. Only records with sufficient documented histories of amputation surgeries, prosthetic services, and mobility status were included.

RESULTS

Of 2,475 patient records reviewed, 1,787 patients (2,157 major amputations) were eligible for analysis. Sixty-two-point 2 percent (n = 1,111) of patients achieved mobility with the collaborative care pathway. Mobility rate varied by amputation level in the study. Prosthetic mobility was achieved in 73.5% of transtibial amputations, 40.4% of transfemoral amputations, and 35.7% of through-knee amputations, regardless of patient laterality, which is superior or equivalent to the best published rates of mobility.

CONCLUSIONS

The study describes the structure and utilization of a physician-led collaborative care pathway for treating patients who require lower-limb amputation that meets 5 of the 7 recommendations from the 2019 Global Vascular Guidelines on the Management of Chronic Limb Threatening Ischemia. Internal data analysis results suggest that patients treated via this care pathway can potentially achieve improved mobility rates with a prosthesis following amputation. This collaborative care pathway should be further evaluated for its ability to directly improve mobility and other clinically relevant amputation outcomes.

Impact of Patient and Procedural Factors on Outcomes Following Mesenteric Bypass

BACKGROUND

Mesenteric bypass (MB) for patients with acute (AMI) and chronic mesenteric ischemia (CMI) is associated with cardiovascular (CV) and pulmonary morbidity.

METHODS

Patients with AMI and CMI from 2008 to 2019 were identified to determine independent predictors of CV (cardiac arrest, MI, DVT, and stroke) and pulmonary (pneumonia and ventilator time>48 h) morbidities in patients undergoing MB.

RESULTS

377 patients were identified. Patients with AMI had higher rates of preoperative SIRS/sepsis (28 vs 12%, P < .0001), were more likely to be ASA class 4/5 (55 vs 42%, P = .005), were more likely to require bowel resection (19 vs 3%, P < .0001), and were more likely to have vein utilized as their bypass conduit (30 vs 14%, P < .0001). There were no differences in use of aortic or iliac inflow (P = .707) nor in return to the OR (24 vs 19%, P = .282). Both postoperative sepsis (12 vs 2.6%, P = .003) and mortality (31.4% vs 9.8%, P < .0001) were significantly increased in patients with AMI. After adjusting for both patient and procedural factors, multivariable logistic regression (MLR) identified international normalized ratio (INR) (OR 3.16; 95% CI 1.56-6.40, P = .001) and chronic heart failure (CHF) (OR 5.88; 95% CI 1.15-29.97, P = .033) to be independent predictors of pulmonary morbidity, while preoperative sepsis (OR 1.96; 95% CI 1.45-2.66, P < .0001) alone was predictive of CV morbidity in all patients undergoing MB.

DISCUSSION

Mesenteric bypass for mesenteric ischemia leads to high rates of morbidity and mortality, whether done in an acute or chronic setting. Preoperative sepsis, independent of AMI or CMI, predicts CV morbidity, regardless of bypass configuration or conduit, while elevated INR or underlying CHF carries a higher risk of pulmonary morbidity.

Risk Factors for Acute Renal Failure After Endovascular Aneurysm Repair

BACKGROUND

Acute kidney injury (AKI) after endovascular aortic aneurysm repair (EVAR) is uncommon though carries significant morbidity. Procedural risk factors are not well established for acute renal failure (ARF) that requires initiation of dialysis. The goal of this study was to examine the impact of ARF on patients undergoing EVAR and identify risk factors for ARF using a large, national dataset.

METHODS

Patients undergoing EVAR were identified from the National Surgical Quality Improvement Program (NSQIP) database over 9 years, ending in 2019. Demographics, indication for repair, comorbidities, procedural details, complications, hospital and ICU LOS, and mortality were recorded. Patients were stratified by presence of ARF and compared. Patients were further stratified by indication for EVAR and presence of ARF. Multivariable logistic regression (MLR) analysis was performed to determine the independent predictors of ARF.

RESULTS

18 347 patients were identified. Of these 234 (1.3%) developed ARF requiring dialysis. Mortality (40 vs 1.8%, P < .0001), ICU LOS (5 vs 0 days, P < .0001), and hospital LOS (11 vs 2 days, P < .0001) were all significantly increased in patients with ARF. Multivariable logistic regression identified increasing diameter, creatinine, operative time, preoperative transfusions, ASA class, emergent repair, female gender, and juxtarenal/suprarenal proximal landing zone as predictors of ARF.

CONCLUSIONS

ARF after EVAR causes significant morbidity, prolongs hospitalizations, and increases mortality rates. Those patients at risk of ARF after EVAR should be closely monitored to reduce both morbidity and mortality.

Five-year outcomes of endosuture aneurysm repair in patients with short neck abdominal aortic aneurysm from the ANCHOR registry

OBJECTIVE

Hostile aortic neck anatomies such as proximal short necks are known to put patients at an increased risk for type IA endoleaks, migration, and need for reinterventions. The Heli-FX EndoAnchor System was designed to improve seal of aortic stent grafts. Endosuture aneurysm repair (ESAR) using EndoAnchors with the Endurant stent graft has been shown to be safe and effective for the treatment of patients with short necks through one year. This study reports the 5-year patient outcomes of the Aneurysm Treatment using the Heli-FX EndoAnchor System Global Registry (ANCHOR) short neck regulatory cohort.

METHODS

The 70 patients from the ANCHOR Registry were cohort submitted to regulators for approval of the Endurant short neck indication. Patients had an infrarenal neck length of ≥ 4 mm and <10 mm. At 5 years, this short neck cohort had clinical and imaging follow-up compliance rates of 85% (28/33) and 70% (23/33), respectively.

RESULTS

The short neck cohort had a mean age of 71.3±8.1 years and was 27.1% (19/70) female. Kaplan Meier freedom from all-cause mortality was 68.5 ± 6.2%, freedom from aneurysm-related mortality was 90.1 ± 4.5%, freedom from any endovascular or surgical secondary procedure was 76.9 ± 7.2%, and freedom from rupture was 95.6 ± 3.2%. Eight patients had a total of nine type IA endoleaks detected through 5 years, of which three resolved spontaneously by the next follow-up visit. There were two patients with renal complications who did not undergo reintervention and there were no device migrations reported through 5 years. After 5 years, 68.2% of patients (15/22) had sac regression, 13.6% (3/22) had stable sacs, and 18.2% (4/22) had increased sac diameter as compared with their 1-month measurements.

CONCLUSIONS

After ESAR treatment using Heli-FX EndoAnchors with Endurant, the 5-year outcomes of the short neck cohort from the ANCHOR registry had encouraging results with regards to proximal neck-related complications, secondary procedures, and sac regression. This review of ESAR in patients with short proximal necks showed positive outcomes through 5 years although follow-up of a larger cohort is necessary.

Prophylactic Left Atrial Appendage Exclusion in Cardiac Surgery Patients With Elevated CHA2DS2-VASc Score: Results of the Randomized ATLAS Trial

OBJECTIVE

Patients with elevated CHA₂DS₂-VASc scores are at high risk for atrial fibrillation (AF) and thromboembolic events (TE) after cardiac surgery. Left atrial appendage exclusion (LAAE) is a permanent, continuous approach to stroke prevention in AF, overcoming limitations of oral anticoagulation (OAC). We report ATLAS trial results focused on LAAE technical success and perioperative safety and TE rates with and without LAAE in cardiac surgery patients who developed postoperative AF (POAF).

METHODS

ATLAS (NCT02701062) was a prospective, multicenter, feasibility trial. Patients age ≥18 years, undergoing structural heart procedure, with no preoperative AF, CHA₂DS₂-VASc ≥2, and HAS-BLED ≥2 were randomized 2:1 to LAAE or no LAAE. Patients who developed POAF and/or received LAAE were followed for 1 year. LAAE was evaluated with intraoperative transesophageal echocardiography.

RESULTS

A total of 562 patients were randomized to LAAE (n = 376) or no LAAE (n = 186). Mean CHA₂DS₂-VASc (3.4 vs 3.4) and HAS-BLED (2.8 vs 2.9) scores were similar for LAAE and no LAAE groups. LAAE success (no flow nor residual stump >10 mm) was 99%. One LAAE-related serious adverse event (0.27%) occurred and was resolved without sequelae. There were 44.3% of patients who developed POAF. Through 1 year, 3.4% of LAAE patients and 5.6% of no LAAE patients had TE. OAC was used by 32.5% of POAF patients. Bleeding was higher with OAC than without (16.1% vs 5.4%, P = 0.008).

CONCLUSIONS

ATLAS demonstrated a high rate of successful LAAE with low LAAE-related serious adverse events in cardiac surgery patients. Study results should be considered in future trial design to further evaluate prophylactic LAAE for stroke prevention in cardiac surgery patients with elevated stroke risk.

Evaluation of Staged TCAR and Cardiac Surgery or Structural Heart Intervention

INTRODUCTION

The optimal treatment strategy for patients with concomitant carotid and cardiac disease remains controversial. Transcarotid artery revascularization stenting with reversed flow protection (TCAR) has achieved results equivalent to carotid endarterectomy (CEA) in high risk patients.

METHODS

A retrospective review of all patients at a single center who received staged TCAR prior to cardiac intervention was performed.

RESULTS

37 patients underwent 42 TCAR procedures prior to cardiac intervention (25 requiring open cardiac surgery and 12 requiring percutaneous intervention). There were no myocardial or neurological complications following TCAR prior to cardiac intervention. Three patients (8%) developed a neck hematoma which required evacuation.

CONCLUSION

A staged approach to combined carotid and cardiac pathology with TCAR prior to cardiac intervention appears to be a safe and effective strategy.

Intraoperative repair of mitral paravalvular leak with Amplatzer plug

BACKGROUND AND AIM OF THE STUDY

Significant paravalvular leaks may complicate mitral valve replacement (MVR), especially in the setting of mitral annular calcification. Correction has been accomplished postoperatively by endovascular delivery of Amplatzer plugs (Abbott Medical) with good results. Intraoperative delivery of Amplatzer plugs at the index operation may reduce postoperative paravalvular leaks.

METHODS

A retrospective review of eight patients who underwent placement of Amplatzer plugs for treatment of paravalvular leak during MVR at a single institution is reported.

RESULTS

Seven patients had ≤1+ residual mitral valve insufficiency and one patient had 1-2+ residual mitral valve insufficiency intraoperatively by transesophageal echocardiogram. At 222 days average follow-up, echocardiogram revealed ≤ 1+ residual mitral valve insufficiency in all surviving patients.

CONCLUSION

Intraoperative delivery of Amplatzer plugs for treatment of paravalvular leaks during MVR appears to be safe and effective at reducing postoperative mitral valve insufficiency.

Extracellular Matrix Patches for Endarterectomy Repair

Patch repair is the preferred method for arteriotomy closure following femoral or carotid endarterectomy. Choosing among available patch options remains a clinical challenge, as current evidence suggests roughly comparable outcomes between autologous grafts and synthetic and biologic materials. Biologic patches have potential advantages over other materials, including reduced risk for infection, mitigation of an excessive foreign body response, and the potential to remodel into healthy, vascularized tissue. Here we review the use of decellularized extracellular matrix (ECM) for cardiovascular applications, particularly endarterectomy repair, and the capacity of these materials to remodel into native, site-appropriate tissues. Also presented are data from two post-market observational studies of patients undergoing iliofemoral and carotid endarterectomy patch repair as well as one histologic case report in a challenging iliofemoral endarterectomy repair, all with the use of small intestine submucosa (SIS)-ECM. In alignment with previously reported studies, high patency was maintained, and adverse event rates were comparable to previously reported rates of patch angioplasty. Histologic analysis from one case identified constructive remodeling of the SIS-ECM, consistent with the histologic characteristics of the endarterectomized vessel. These clinical and histologic results align with the biologic potential described in the academic ECM literature. To our knowledge, this is the first histologic demonstration of SIS-ECM remodeling into site-appropriate vascular tissues following endarterectomy. Together, these findings support the safety and efficacy of SIS-ECM for patch repair of femoral and carotid arteriotomy.

Erosion of a right ventricular pacer lead into the left chest wall

Background

Erosion of a pacer lead into the chest wall may result in pericardial effusion with cardiac tamponade. Free rupture into the pleura or mediastinum can result in hypotension and cardiac arrest.

Case presentation

We report a unique case of a right ventricular pacer lead which eroded through the right ventricle into the left chest wall and penetrated a rib. The patient presented with a tender chest wall mass without pericardial or pleural effusion. The segment of rib which the pacing lead had penetrated was removed.

Conclusions

The patient tolerated the procedure well and was discharged 1 week after the operation. This case adds to the current literature the justification of removal of temporary and non-functional pacing leads.

Safety Profile of an Intra-Annular Self-Expanding Transcatheter Aortic Valve and Next-Generation Low-Profile Delivery System

OBJECTIVES

The aim of this study was to characterize the safety profile of an intra-annular self-expanding valve with a next-generation low-profile delivery system (DS).

BACKGROUND

Key design modifications to the FlexNav DS include the addition of a hydrophilic-coated, integrated sheath and stability layer to facilitate gradual, controlled deployment in vessels with diameter ≥5 mm.

METHODS

Patients were pooled from 2 concurrent prospective, multicenter, single-arm studies (FlexNav DS arm of PORTICO IDE [Portico Re-Sheathable Transcatheter Aortic Valve System U.S. IDE Trial] [n = 134] and the FlexNav EU CE Mark Study [n = 46]) for the analysis. The primary endpoint was Valve Academic Research Consortium-2-defined major vascular complications at 30 days. Clinical outcomes and valve performance were assessed through 30 days by an independent clinical events committee and an echocardiography core laboratory, respectively.

RESULTS

One hundred forty high-risk and 40 extreme-risk subjects enrolled between October 15, 2018, and December 10, 2019, from 28 sites in the United States, Australia, and Europe who underwent attempted transfemoral Portico valve implantation were included. The mean age was 85.1 ± 5.6 years, 60% were women, the mean Society of Thoracic Surgeons score was 5.3%, and 96.1% presented with ≥1 frailty factor. Technical device success was 96.7%. At 30 days, the rate of major vascular complications was 5.0%, with 4.4% of complications adjudicated as access site-related (3.3% transcatheter aortic valve replacement DS access site-related). Death (0.6%) and disabling stroke (1.1%) were rare. The rate of new permanent pacemaker implantation was 15.4%. Echocardiography revealed a mean gradient of 7.1 ± 3.2 mm Hg, mean valve area of 1.77 ± 0.41 cm², and a 4.1% rate of moderate paravalvular leak at 30 days.

CONCLUSIONS

Portico valve implantation with the FlexNav DS was associated with an excellent safety profile at 30 days.

Diagnosis and relining techniques for delayed type IIIB endoleaks with the second-generation AFX endograft

Type IIIB endoleaks resulting from endograft fabric tear are an uncommon but serious late complication of endovascular aortic aneurysm repair. The Strata fabric used in the earlier generation AFX endograft (updated to Duraply in October 2014) has been associated with an increased frequency of these events. Herein we report on two patients exhibiting delayed type IIIB endoleaks after AFX device insertion to treat an abdominal aortic aneurysm and discuss optimal relining techniques.

Migrated embolization coil causes intestinal obstruction

Visceral artery pseudoaneurysm is a rare, potentially fatal entity, but proper identification and management with coil embolization can lead to good outcomes. Embolization coils can migrate to various destinations, causing delayed complications in several case reports. A case of small bowel obstruction due to migrated embolization coils from a gastroduodenal pseudoaneurysm 6 years after initial treatment is presented.

Delayed Metallic Embolization of a Cor-Knot Fastener

Background  The Cor-Knot device is a titanium fastener which is widely used in cardiac valve procedures. Adverse events associated with use of the device have been rare.

Case Description  A patient underwent robotic mitral valve repair using the Cor-Knot fastener. Five years later, he suffered a cerebral vascular accident secondary to embolization of a metallic foreign body. He had had no other medical procedures which could account for a source of metallic embolization.

Conclusion  Long-term surveillance after use of the Cor-Knot fastener is limited. Metallic embolization may be possible with this device and warrants awareness within the medical community.

Coil Embolization of Spontaneous Splenic Arteriovenous Fistula for Treatment of Portal Hypertension

Patient: Female, 64

Final Diagnosis: Splenic arteriovenous fistula

Symptoms: Left lower quadrant abdominal pain

Medication: —

Clinical Procedure: Coiling embolization

Specialty: Surgery

Treatment of Aortoiliac Occlusive Disease with the Endologix AFX Unibody Endograft

OBJECTIVE/BACKGROUND

Aorto-bifemoral bypass remains the gold standard for treatment of aortoiliac occlusive disease (AIOD) in patients with advanced (TASC D) lesions, but has significant associated morbidity and mortality. Treatment with a unibody stent-graft positioned at the aortic bifurcation is a potential endovascular option for the treatment of AIOD. The current study examines the safety, efficacy, and early patency rates of the Endologix AFX unibody stent-graft for treatment of AIOD.

METHODS

A multicenter retrospective review was conducted of patients treated exclusively for AIOD with the AFX device. Primary, assisted primary, and secondary patency rates were noted. Clinical improvement was assessed using Rutherford classification and ankle brachial index. Mean duration of follow-up was 22.2 ± 11.2 months. Ninety-one patients (56 males [62%]) were studied.

RESULTS

Sixty-seven patients (74%) presented with lifestyle-limiting intermittent claudication and the remaining 24 (26%) had critical limb ischemia. Technical success was 100%. Complications included groin infection (n = 4 [4%]), groin hematoma (n = 4 [4%]), common iliac rupture (n = 4 [4%]), iliac dissection (n = 4 [4%]), and thromboembolic event (n = 3 [3%]; one femoral, one internal iliac artery, and one internal iliac with bilateral popliteal/tibial thromboemboli). Thirty-day mortality was 1% (1/91) resulting from a case of extensive pelvic thromboembolism. At 1 year, 73% of patients experienced improvement in Rutherford stage of -3 or greater compared with baseline. Nine patients (10%) required 16 secondary interventions. At all time points, primary patency rates were > 90%, assisted patency rates were > 98%, and secondary patency rates were 100%.

CONCLUSION

This is the largest study to examine the use of the Endologix AFX unibody stent-graft for the treatment of AIOD. Use of the AFX stent-graft appears to be a safe and effective endovascular treatment for complex AIOD.

Sternal closure with rigid plate fixation versus wire closure: a randomized controlled multicenter trial

BACKGROUND

Rigid bone fixation is the standard of care for all bone reconstructions except that after sternotomy. Sternal reconstruction after median sternotomy using rigid fixation with plates may improve bone healing and reduce pain when compared with wire cerclage.

METHODS

One-hundred forty patients at six centers who were determined preoperatively to be at high risk for sternal wound complications were randomly assigned to sternal closure with rigid plate fixation (n=70) or wire cerclage (n=70). Sternal healing was evaluated at 3 or 6 months by a core laboratory using computed tomography. Pain and function were evaluated at postoperative day 3 through discharge, 3 weeks, 6 weeks, 3 months, and 6 months.

RESULTS

Sternal healing was superior in rigid plate fixation patients at both 3 and 6 months. Mean computed tomography scores in the rigid plate fixation and wire cerclage groups at 3 months were 1.7±1.1 and 0.9±0.8 (p=0.003). At 6 months, the scores were 3.2±1.6 and 2.2±1.1, respectively (p=0.01). At 6 months, 70% of rigid plate fixation patients had achieved sternal union, compared with 24% of conventional wire cerclage patients (p=0.003). Pain scores and narcotic usage were lower in rigid plate fixation patients. Significant differences in pain scores were observed at 3 weeks for total pain (p=0.020) and pain with coughing (p=0.0084) or sneezing (p=0.030). Complication rates were similar in both groups.

CONCLUSIONS

Sternal reconstruction using rigid fixation with plates improved bone healing and reduced early postoperative pain compared with wire cerclage.

Staged total exclusion of the aorta for chronic type B aortic dissection

Hybrid techniques using extra-anatomic bypass of critical aortic branches to enable endovascular treatment of complex aortic pathology have been previously described. A staged endograft repair of a complex, chronic Stanford type B aortic dissection with aneurysmal degeneration is reported in a 50-year-old man. The aneurysmal portion of the dissection extended from the distal arch to both common iliac arteries and was covered with an endograft from the ascending aorta to both external iliac arteries. Aortic arch branches, visceral, and renal arteries were bypassed using open technique. The patient had no neurologic complications. This case report illustrates the feasibility of the hybrid technique in selected high-risk patients when confronted with complex aortic pathology.

Endovascular management of iliac rupture during endovascular aneurysm repair

BACKGROUND

Inadequate iliac artery diameter, calcification, and tortuosity are associated with increased incidence of iliac injury during abdominal (EVAR) and thoracic endovascular aneurysm repair (TEVAR). Despite careful preoperative assessment and use of iliac conduits, inadvertent iliac rupture is a source of morbidity and mortality. This report details our single-center, 10-year experience with intraoperative iliac artery rupture and describes a successful endovascular salvage technique.

METHODS

All patients undergoing EVAR and TEVAR between August 1997 and June 2008 were reviewed. Computed tomography (CT) measurements of access vessels were obtained for all patients. The smallest diameter of the external or common iliac artery was used to determine suitability for access based on the instructions for use for each device. Patients who underwent repair of a procedure-related iliac artery rupture were identified. Outcomes among patients who did not have an access vessel rupture (nonruptured group) and those who did (ruptured group) were compared. Patency of the endovascular iliac repair is reported.

RESULTS

During the study period, 369 EVARs and 67 TEVARs were performed. Eleven iliac conduits were used, all during TEVAR (16%). There were 18 ruptured iliac arteries in 17 patients; 11 EVAR patients (2.98%) sustained iliac rupture vs six TEVAR patients (8.9%). One EVAR patient was converted to open repair. Seventeen ruptures in 16 patients were successfully treated with endovascular stent graft placement. Iliac rupture was more likely to occur during TEVAR (8.9%) than EVAR (2.98%; P = .0239, Fisher exact test). Significantly more women were in the ruptured group (76% vs 19%; P < .0001, Fisher exact test). Patients in the ruptured group had longer lengths of stay (7.6 vs 5.1 days; P = .0895, t test), no 30-day mortality, but a procedure-related mortality of 11.8%. In the nonrupture group, 30-day mortality was 6.6% (4 of 61) and 2.8% (10 of 358) for TEVAR and EVAR, respectively, and procedure-related mortality was 9.8% (6 of 61) and 3.1% (11 of 358). For endovascular repair of iliac rupture, primary and primary-assisted patency was 88.2% and 94.1%, respectively, with median follow-up of 40 months (range 10-115 months).

CONCLUSION

Iliac rupture during EVAR or TEVAR can be successfully managed with endovascular stent grafting. Higher mortality and length of stay associated with iliac artery rupture confirm that there is no substitute for prevention. Access vessels of all patients undergoing EVAR should be examined closely for suitability. The threshold for using an iliac conduit, especially in women undergoing TEVAR, should be low.

Secondary pneumomediastinum: a retrospective comparative analysis

Pneumomediastinum is an uncommon radiographic finding of potential clinical significance. Secondary pneumomediastinum (SPM) has a variety of etiologies that can lead to potentially morbid outcomes. There are limited data regarding the etiologies, diagnosis, and outcomes of this entity. A retrospective comparative study was conducted over an 11-year period of patients developing pneumomediastinum secondary to a specific pathologic or traumatic event. Forty-five patients were identified with an underlying condition resulting in SPM. Demographic data, radiologic findings, length of hospital stay, and mortality were recorded. Statistical comparison was conducted between patients with blunt thoracic trauma- and barotrauma-induced pneumomediastinum. Logistic and multiple linear regression analyses were performed to discover factors predictive of mortality and length of hospital stay. Median age of the patients was 40 years and 69% were men. Subcutaneous emphysema was identified in 44%, pneumothorax in 47%, and pleural effusion in 11%. Pneumomediastinum was identified by plain radiograph (CXR) in only 47% compared to 100% by computed tomogram (CT scan). Average length of hospital stay was 19 days and mortality was 38%. Patients with blunt thoracic trauma had a lower sensitivity for CXR to discover pneumomediastinum, were more likely to develop subcutaneous emphysema or pneumothorax, and had lower mortality and length of hospital stay compared with those with barotrauma-induced pneumomediastinum. Barotrauma was an independent predictor for hospital mortality. Secondary pneumomediastinum is a morbid condition with distinctive etiologies, radiologic findings, and outcomes. Barotrauma-induced pneumomediastinum is associated with a prolonged recovery and high mortality rate.

Robot-assisted laparoscopic aortobifemoral bypass: initial experience developing a new program

Despite improved technology for endovascular treatment of aorto iliac occlusive disease, aortobifemoral bypass (ABF) continues to offer superior long-term patency. In an effort to reduce the morbidity of surgical ABF, multiple minimally invasive techniques have been reported. The da Vinci robot may facilitate the construction of a minimally invasive aortic anastomosis using standard vascular suture techniques. Our initial experience in the development of a minimally invasive surgical aortic reconstruction program is reported. After extensive time in the laboratory developing our surgical technique in human cadavers and a pig model, our team initiated a robotic vascular surgery program in 2007. A retrospective review of our initial six robot-assisted laparoscopic ABF cases was conducted. The aorta was exposed laparoscopically using the Stadler technique and the aortic anastomosis performed with the da Vinci robot. These results are compared with currently published reports of robotic ABF and alternative methods of minimally invasive aortic reconstruction. From January 2007 to August 2007, six robot-assisted laparoscopic ABFs were performed. Two patients had prior abdominal surgical procedures. Four patients had prior endovascular or surgical aorto iliac reconstruction. Operative time varied from 5 h 26 min to 8 h 12 min. Total clamp time, for the aortic anastomosis, ranged from 70 to 100 min with a mean of 75 min. Estimated blood loss ranged from 300 to 2,000 ml with a mean of 850 ml. Conversion with a short upper midline incision was required in one patient (16%) with an associated abdominal aortic aneurysm. Post operative length of stay ranged from five to ten days with a median of seven days. There was no operative mortality. Results from robotically assisted laparoscopic ABF are equivalent to those from other minimally invasive options while enabling a much shorter learning curve. Using the technique described, minimally invasive ABF was accomplished in a safe and reliable manner despite prior vascular treatment.

Spontaneous pneumomediastinum: a comparative study and review of the literature

BACKGROUND

Spontaneous pneumomediastinum (SPM) is an unusual occurrence with few cases reported. It is seen after intrathoracic pressure changes leading to alveolar rupture and dissection of air along the tracheobronchial tree. This study was undertaken to provide a thorough clinical and radiologic analysis of this patient population.

METHODS

A retrospective comparative analysis was performed on patients with SPM over 12 years. Patient demographics, clinical presentation, and radiographic and diagnostic studies were recorded. A clinical and radiologic comparison was performed with secondary pneumomediastinum.

RESULTS

Seventy-four patients were identified with a diagnosis of pneumomediastinum. A total of 28 patients with SPM were identified. The major initial complaints were chest pain (54%), shortness of breath (39%), and subcutaneous emphysema (32%). The main triggering events were emesis (36%) and asthma flare-ups (21%). No apparent triggering event was noted in 21% of patients. Chest radiograph was diagnostic in 69%; computed tomography was required in 31%. Esophagram, esophagoscopy, and bronchoscopy were performed on an individual basis and were invariably negative. When compared with secondary pneumomediastinum, SPM is more likely to be discovered by chest radiography, has a lower incidence of pneumothorax and pleural effusion, requires a shorter hospital stay, and has no associated mortality.

CONCLUSIONS

Spontaneous pneumomediastinum is a benign condition that often presents with chest pain or dyspnea. It can develop without a triggering event and with no findings on chest radiography. Treatment is expectant and recurrence is low. Secondary causes must be ruled out to avoid an unfavorable outcome.

Robot-assisted minimally invasive procedure for descending aorta--bifemoral bypass: a case report

In the patient who can withstand the added physiologic stress of descending thoracic aortic clamping, thoracofemoral bypass may have the advantages of longer durability and increased perfusion when compared with axillobifemoral bypass. Using thorascopic techniques and a robot to perform the anastomosis, this procedure may be performed in a less invasive manner.

Bioremediation of atrazine-contaminated soil by forage grasses: transformation, uptake, and detoxification

A sound multi-species vegetation buffer design should incorporate the species that facilitate rapid degradation and sequestration of deposited herbicides in the buffer. A field lysimeter study with six different ground covers (bare ground, orchardgrass, tall fescue, timothy, smooth bromegrass, and switchgrass) was established to assess the bioremediation capacity of five forage species to enhance atrazine (ATR) dissipation in the environment via plant uptake and degradation and detoxification in the rhizosphere. Results suggested that the majority of the applied ATR remained in the soil and only a relatively small fraction of herbicide leached to leachates (<15%) or was taken up by plants (<4%). Biological degradation or chemical hydroxylation of soil ATR was enhanced by 20 to 45% in forage treatment compared with the control. Of the ATR residues remaining in soil, switchgrass degraded more than 80% to less toxic metabolites, with 47% of these residues converted to the less mobile hydroxylated metabolites 25 d after application. The strong correlation between the degradation of N-dealkylated ATR metabolites and the increased microbial biomass carbon in forage treatments suggested that enhanced biological degradation in the rhizosphere was facilitated by the forages. Hydroxylated ATR degradation products were the predominant ATR metabolites in the tissues of switchgrass and tall fescue. In contrast, the N-dealkylated metabolites were the major degradation products found in the other cool-season species. The difference in metabolite patterns between the warm- and cool-season species demonstrated their contrasting detoxification mechanisms, which also related to their tolerance to ATR exposure. Based on this study, switchgrass is recommended for use in riparian buffers designed to reduce ATR toxicity and mobility due to its high tolerance and strong degradation capacity.

Improved HPLC-MS/MS method for determination of isoxaflutole (balance) and its metabolites in soils and forage plants

A robust multi-residue procedure is needed for the analysis of the pro-herbicide isoxaflutole and its degradates in soil and plant materials at environmentally relevant (<1 microg kg-1) levels. An analytical method using turbo-spray and heat-nebulizer high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for the analysis of isoxaflutole (IXF) and its two metabolites, diketonitrile (DKN) and the benzoic acid metabolite (BA), at sub-microgram per kilogram levels in soil and plant samples. The average recoveries of the three compounds in spiked soil and plant samples ranged from 84 to 110% and 94 to 105%, respectively. The limits of quantification were validated at 0.06 microg kg-1 for soil and 0.3 microg kg-1 for plant samples. The limits of detection (LOD) for soil analysis were 0.01, 0.002, and 0.01 microg kg-1 for IXF, DKN, and BA, respectively. Corresponding LOD for the plant analysis method were 0.05, 0.01, and 0.05 microg kg-1. The developed method was validated using forage grass and soil samples collected from a field lysimeter study in which IXF was applied to each of four forage treatments. Forage plants and soils were sampled for analyses 25 days after IXF application to the soil. In soils, IXF was not detected in any treatment, and DKN was the predominant metabolite found. In forage plants, the concentrations of DKN and BA were 10-100-fold higher than that in soil samples, but IXF was not detected in any forage plants. The much higher proportion of BA to DKN in plant tissues (23-53%), as compared to soils (0-5%), suggested that these forages were capable of detoxifying DKN. The developed methods provided LODs at sub-microgram per kilogram levels to determine the fate of IXF and its metabolites in soils and forage plants, and they also represent considerable improvements in extraction recovery rates and detection sensitivity as compared to previous analytical methods for these compounds.

Large pedunculated polyps originating in the esophagus and hypopharynx

Large pedunculated esophageal and hypopharyngeal polyps are uncommon. Clinical presentation most commonly includes dysphagia and mass regurgitation. If left untreated the patient may develop polyp aspiration complicated by fatal asphyxiation. Diagnosis has depended on endoscopy and barium swallow historically; however, these procedures may fail to provide a diagnosis. In recent years computerized tomographic scan and magnetic resonance imaging have proved reliable methods of diagnosis. These polyps are located predominantly in the upper esophagus and frequently are comprised of a fibrous component. Malignant potential is low. Resection of these lesions is warranted; it may be approached endoscopically if feasible or surgically through a cervical or thoracotomy approach, depending on the location. Recurrence is rare. To our knowledge, this is the largest review of large esophageal polyps, including 110 reported cases in the literature.

Ruptured aneurysm of the inferior thyroid artery: repair with coil embolization

Although pseudoaneurysm of the thyrocervical trunk is seen with increasing frequency as a result of trauma or central venous cannulation, true aneurysm of the thyrocervical trunk is exceedingly rare. A 44-year-old woman presented with acute left neck swelling that progressed rapidly to respiratory distress and subsequent hemothorax. Emergency endotracheal intubation was performed for airway control, and tube thoracostomy was placed for drainage of the pleural space. A review of the literature reveals that this is the second patient known to be successfully treated by arterial embolization of a ruptured aneurysm of the inferior thyroid artery and the fifteenth known case of aneurysm of the inferior thyroid artery. Surgical or endovascular intervention has been successful. Observation has been uniformly fatal. Because life-threatening rupture is possible, the presence of this aneurysm mandates intervention. Endovascular coil embolization is a viable option for treatment of this entity.

Treatment of Vascular Rejection With Rituximab in Cardiac Transplantation

BACKGROUND

Vascular rejection is the B-cell-mediated production of immunoglobulin G (IgG) antibody against the transplanted heart. The currently available treatments for vascular rejection have had limited success, and chronic manifestations of vascular rejection require re-transplantation. Rituximab is a monoclonal antibody directed against the CD20 receptor of B-lymphocytes, which is approved for treatment of lymphoma.

METHODS

Vascular rejection was defined as positive immunofluorescent endomyocardial biopsy staining for IgG and complement, 25% reduction in left ventricular ejection fraction (LVEF) from baseline, and absence of cellular rejection. Over the last 3 years, 8 patients with vascular rejection were treated with intravenous rituximab at a dose of 375 mg/m2 per week for 4 weeks.

RESULTS

All patients had normal LVEF post-transplant (average 58%), but developed left ventricular dysfunction (average decrease of 43%) associated with endomyocardial biopsy evidence of vascular rejection. Post-treatment, LVEF returned to baseline (average 53%) with complete resolution of immunofluorescent staining by endomyocardial biopsy. No patient suffered significant infection or drug-related complications.

CONCLUSIONS

Rituximab is beneficial for treatment of vascular rejection. Further study is indicated to verify the safety, efficacy and mechanism of action of rituximab therapy for vascular rejection.

The effect of five forage species on transport and transformation of atrazine and isoxaflutole (balance) in lysimeter leachate

A field lysimeter study with bare ground and five different ground covers was established to evaluate the effect of forage grasses on the fate and transport of two herbicides in leachate. The herbicides were atrazine (ATR; 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) and isoxaflutole [IXF; 5-cyclopropyl-4-(2-methylsulfonyl-4-trifluormethyl-benzoyl)isoxazole], which has the commercial name Balance (Aventis Crop Science, Strasbourg, France). The ground covers included orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), tall fescue (Festuca arundinacea Schreb.), timothy (Phleum pratense L.), and switchgrass (Panicum virgatum L.). The results suggested that the total IXF (parent + metabolites) showed higher mobility than ATR and its metabolites. Differences in the timing of transport reflected the rapid degradation of IXF to the more soluble, stable, and biologically active diketonitrile (DKN) metabolite in the system. Although grass treatments did not promote the hydrolysis of DKN, they significantly reduced its transport in the leachate through enhanced evapotranspiration. Grass treatments significantly enhanced ATR degradation in the leachates and soils, especially through N dealkylation, but they did not reduce total ATR transported in the leachate. Leachate from the orchardgrass lysimeters contained the highest proportion of ATR metabolites (64.2%). Timothy and smooth bromegrass treatments also displayed a significant increase in ATR metabolites in leachate. Grass-treated lysimeters showed higher microbial biomass carbon than bare ground. For ATR treatments, the proportion of metabolites in the leachate strongly correlated with the elevated soil microbial biomass carbon in forage treatments. In contrast, DKN degradation was poorly correlated with soil microbial biomass carbon, suggesting that DKN degradation is an abiotic process.

Effect of acute drought stress and time of harvest on phytochemistry and dry weight of St. John's wort leaves and flowers

The phytochemistry and dry weight of cultivated St. John's wort are significantly influenced by acute drought stress and time of harvest. In this study, plants subjected to brief drought stress during both flower and seed development periods exhibited increased concentrations in 8 of the 10 phytochemicals examined in this study, including hypericin, pseudohypericin, chlorogenic acid, rutin, hyperoside, isoquercitrin, quercitrin, and quercetin. Increases ranged from 5% to 36% (hyperoside and rutin, respectively). Conversely, the concentrations of hyperforin and adhyperforin in flowers were decreased by an average of 10% in drought-stressed plants as compared to well-watered control plants. Acute drought stress decreased flower dry weight significantly during both drydown periods, although vegetative parameters (height, leaf dry weight and stem dry weight) were not adversely affected. While acute drought stress significantly altered the chemical yield in the leaves and flowers (phytochemical content x harvested dry weight), the time of harvest was the predominant factor determining phytochemical concentration in the organs of H. perforatum.

Effect of acute drought stress and time of harvest on phytochemistry and dry weight of St. John's wort leaves and flowers

The phytochemistry and dry weight of cultivated St. John's wort are significantly influenced by acute drought stress and time of harvest. In this study, plants subjected to brief drought stress during both flower and seed development periods exhibited increased concentrations in 8 of the 10 phytochemicals examined in this study, including hypericin, pseudohypericin, chlorogenic acid, rutin, hyperoside, isoquercitrin, quercitrin, and quercetin. Increases ranged from 5% to 36% (hyperoside and rutin, respectively). Conversely, the concentrations of hyperforin and adhyperforin in flowers were decreased by an average of 10% in drought-stressed plants as compared to well-watered control plants. Acute drought stress decreased flower dry weight significantly during both drydown periods, although vegetative parameters (height, leaf dry weight and stem dry weight) were not adversely affected. While acute drought stress significantly altered the chemical yield in the leaves and flowers (phytochemical content x harvested dry weight), the time of harvest was the predominant factor determining phytochemical concentration in the organs of H. perforatum.

Treatment of humoral rejection with rituximab

Humoral vascular rejection is a B cell-mediated production of immunoglobulin G antibody against the transplanted organ. Available treatments of vascular rejection offer limited success, and chronic manifestations of vascular rejection require retransplantation. On the basis of the mechanism of action of rituximab, we successfully treated 1 patient with vascular rejection refractory to plasmapheresis with this drug without major toxicity.

A human cadaveric circulation model

Although endovascular techniques have achieved widespread acceptance, a suitable model for device development and physician training has not been available. Plastic models of the arterial tree and live animal models have significant limitations. Arterial-to-arterial flow is established in fresh frozen human cadavers after a simple thrombolytic process to achieve a more realistic model for endovascular device testing and training. Circulation can be established through most of the arterial system, including the cerebral, aortoiliac, and extremity vessels. This model offers antegrade flow in human arterial anatomy and has been used successfully for physician training and device development.

Simultaneous determination of the predominant hyperforins and hypericins in St. John's Wort (Hypericum perforatum L.) by liquid chromatography

Hypericin and hyperforin are believed to be among the active constituents in common St. John's wort (Hypericum perforatum L.). Presently, dietary supplements are generally standardized to contain specified levels of hypericin and hyperforin, and the related compounds, pseudohypericin and adhyperforin. A rapid method was developed for simultaneous determination of these 4 active constituents by liquid chromatography (LC). A 1 g portion of dried, finely ground leaf/flower sample is extracted with 20 mL methanol for 2 h. A 0.6 mL aliquot of the crude extract is combined with 5.4 mL acetonitrile-methanol (9 + 1) and passed through a mixed solid-phase cleanup column. The eluate is examined by LC for hyperforin, adhyperforin, hypericin, and pseudohypericin on a Hypersil reversed-phase column by using simultaneous ultraviolet (284 nm) and fluorescence detection (excitation, 470 nm; emission, 590 nm). The compounds are easily separated isocratically within 8 min with a mobile phase of acetonitrile-aqueous 0.1 M triethylammonium acetate (8 + 2). Average recoveries of hyperforin and adhyperforin were 101.9 and 98.4%, respectively, for 3 sample mixtures containing concentrations ranging from approximately 0.2 to 1.5% combined hyperforins per gram dry weight. Average relative standard deviation (RSD) values for hyperforin and adhyperforin for all 3 mixtures were 18.9 and 18.0%, respectively. Average recoveries of hypericin and pseudohypericin were 88.6 and 93.3% respectively, from 3 sample mixtures containing concentrations ranging from approximately 0.2 to 0.4% combined hypericins per gram dry weight. Average RSD values for hypericin and pseudohypericin for all 3 mixtures were 3.8 and 4.2%, respectively.

Prosthetic above-knee femoropopliteal bypass grafting: five-year results of a randomized trial

PURPOSE

This trial was designed to identify factors affecting patency rates of primary prosthetic above-knee femoropopliteal bypass grafts at 5 years.

METHODS

A multi-institutional, prospective trial randomized 240 patients to compare patency rates of Gore-tex and Hemashield above-knee femoropopliteal bypass grafts at 5 years. Univariate comparisons of patency between levels of each prognostic variable were made with the Kaplan-Meier method. Variables that had a univariate P value less than.25 or those known to be important were submitted to a Cox regression analysis.

RESULTS

The patient survival rate at 5 years was 59.4%. There were no differences in primary or secondary patency rates at 5 years between the two graft materials (primary, 45% vs 43% and secondary, 68% vs 68%). The risk for graft occlusion was significantly increased for patients younger than 65 years (2.1; P =.001) and for grafts with a diameter less than 7 mm (1.65; P =.0219). Variables with no apparent independent effect on patency rates were smoking status, runoff, diabetes mellitus, sex, presenting symptoms, and postoperative treatment with aspirin or Coumadin. Noninvasive test results were not predictive of subsequent graft function.

CONCLUSION

Although the type of prosthetic used for above-knee femoropopliteal bypass grafts does not affect 5-year patency rates, age and graft size do influence results. These factors should be considered before a prosthetic bypass grafting procedure. Furthermore, these data should serve as a contemporary standard, with which evolving and conventional procedures can be compared.

Complete direct mammary harvest for minimally invasive coronary artery bypass

Minimally invasive coronary artery bypass has primarily involved left internal mammary artery grafting to the left anterior descending coronary artery through a small left anterior thoracotomy incision. Harvesting of the mammary artery has been accomplished completely using a video-assisted thoracoscopic technique or incompletely to the second interspace under direct vision. With a mammary retractor, the mammary artery can be dissected completely under direct vision, thus eliminating any criticism of an incomplete harvest and any increased difficulty or expense associated with the thoracoscopic harvest. In this series, all 17 mammary arteries were successfully harvested completely under direct vision and 16 patients underwent successful minimally invasive coronary bypass.

Prosthetic above-knee femoropopliteal bypass grafting: results of a multicenter randomized prospective trial. Above-Knee Femoropopliteal Study Group

PURPOSE

There are excellent arguments in favor of the preferential use of prosthetic grafts above the knee for the treatment of infrainguinal occlusive disease. This approach has been popularized on the basis of the seemingly acceptable results when using polytetrafluoroethylene (PTFE). However, in many centers, knitted Dacron polyester has been used in these patients, and there are several studies that show equivalent and, in some, superior results with Dacron when compared with PTFE. The purpose of this study was to examine these results in a definitive way.

METHODS

A randomized prospective trial in eight clinical academic centers in the United States and Canada was initiated in 1991. Two hundred forty-four patients eligible for such a study, by virtue of criteria extant in each institution at the time, were centrally randomized. They underwent placement of either a knitted Dacron polyester graft impregnated with collagen or a thin-wall expanded reenforced PTFE graft to the above-knee popliteal artery, usually from the common femoral artery. They were frequently observed by protocol for as long as 5 years by a physical examination noninvasive hemodynamic study, including duplex scanning in many instances. Continuing patency was noted, as were other potential adverse outcome events. The data were analyzed by the log-rank test for cumulative patency and expressed as Kaplan-Meier curves. Data were further analyzed with a Cox proportional hazards model.

RESULTS

There were no differences in graft groups in demographic or comorbid factors. The procedural mortality rate was zero, and the morbidity rate was low (6.5%). The long-term patient survival rate was excellent (77% at 3 years). At the end of these years, no statistical significance in primary or secondary patency rates was observed between the two grafts (primary patency rate, 62% +/- 14.4% for Dacron; 57% +/- 15.5% for PTFE). No unexpected adverse outcomes on limb status were noted. Patency rates in both graft groups were inferior in patients who received small grafts (5 to 6 mm vs 7 to 8 mm; hazards ratio, 4.15) and younger (<65 years) smoking patients.

CONCLUSIONS

The fact that these two prosthetic grafts performed in equivalent fashion in a controlled, well-conducted prospective study is not surprising in spite of the previous work that suggested differences. If the preferential use of synthetic bypass grafts above the knee is to be used, it should be restricted to older nonsmokers with favorable anatomy. In that instance, the choice of graft material will depend on handling characteristics and cost. Above-knee prostheses should be only selectively used in younger, smoking patients, and graft size should be carefully considered in patients who undergo this operation.

Aortocoronary bypass with saphenous vein graft. Seven-year follow-up. 1973

A 42-year-old man had extensive occlusive disease of the coronary artery and angina pectoris. An autogenous saphenous vein bypass from the ascending aorta to the anterior descending coronary artery was performed on Nov 23, 1964. The patient suffered an asymptomatic anterior myocardial infarction during operation but made an uncomplicated recovery. Seven years after the operation, the graft functions with normal left ventricular hemodynamics, while the occlusive process has produced obstruction of the left main coronary artery and almost complete occlusion of the right coronary artery. To our knowledge, this is the first successful case of a saphenous vein-coronary artery bypass with the longest follow-up of a functioning coronary vein bypass graft.

Boric acid-phenolic relationships within the Pinus echinata-Pisolithus tinctorius ectomycorrhizal association

At germination, container-grown shortleaf pine seedlings were inoculated with Pisolithus tinctorius (Pers.) Coker & Couch or left uninoculated, and both groups were fertilized semiweekly with a modified Hoagland's solution supplemented with 0 or 0.4 mM boric acid. After 12, 16 and 24 weeks, seedling root tissue was analyzed for ectomycorrhizal colonization, phenolic concentration and phenoloxidase activity. In addition, phenoloxidase activity was assayed in P. tinctorius that had been cultured in a liquid medium containing boric acid. Inoculation with P. tinctorius increased the root phenolic concentration of 16- and 24-week-old seedlings, and increased root phenoloxidase activity in 12-, 16- and 24-week-old seedlings. Fertilization with boric acid reduced the phenolic concentration of P. tinctorius ectomycorrhizae after 24 weeks. Although boric acid fertilization did not affect the phenoloxidase activity of 12-, 16- and 24-week-old inoculated roots, or that of 16- and 24-week-old uninoculated roots, it increased the phenoloxidase activity of P. tinctorius grown in vitro and 12-week-old uninoculated roots. We conclude that boric acid fertilization influences the phenolic relations of the shortleaf pine-P. tinctorius ectomycorrhizal association, possibly through a boric acid-induced increase in phenoloxidase activity.

Pulmonary capillary hemangiomatosis: a clinicopathologic review

Pulmonary capillary hemangiomatosis is a locally aggressive benign vascular neoplasm of the lung characterized by the presence of numerous cytologically benign thin-walled capillary-sized blood vessels proliferating diffusely through the pulmonary interstitium, in and around pulmonary vessels and airways. Pulmonary capillary hemangiomatosis is a rare disease characterized by pulmonary hypertension and a slowly progressive clinical course; it is frequently misdiagnosed clinically as primary pulmonary hypertension and veno-occlusive disease. The purpose of this review is to describe the clinical, radiologic, and histologic features of this rare form of pulmonary vascular neoplasm, which may present considerable diagnostic problems to both the clinician and the histopathologist. Fourteen cases of pulmonary capillary hemangiomatosis have been previously reported. In this review we describe the fourth case of pulmonary capillary hemangiomatosis in which the diagnosis was made antemortem, as well as the fourth to undergo lung transplantation.