Acute Real-World Outcomes From the Phoenix Post-Approval Registry.

OBJECTIVES: An evaluation of the 30-day safety and performance outcomes of the Phoenix atherectomy system (Philips Volcano Corporation) was performed in real-world patients with peripheral artery disease (PAD). METHODS: The Phoenix Post-Approval Registry is an all-comer study that enrolled patients with infrainguinal PAD. Patients treated with the Phoenix atherectomy system were followed for 30 days to observe device-related complications. Outcomes evaluated include procedural (final target lesion(s) residual stenosis of ≤30% after treatment with Phoenix and any other adjunctive therapy) and technical success (defined as achieving a post-Phoenix [prior to any adjunctive therapy] residual diameter stenosis of ≤50%), target-vessel revascularization (TVR), target-lesion revascularization (TLR), target-limb amputation, ankle brachial index, Rutherford clinical category, and wound, ischemia, foot infection (WIfI) classification. RESULTS: Of the 500 patients enrolled, 259 had CLI, including 26.3% with Rutherford class 6. Procedural success rates were 97.3% for non-CLI patients and 98.2% for CLI patients. Technical success rates were 71.5% for non-CLI patients and 77.9% for CLI patients. Complication rates post Phoenix atherectomy were <1%. Through the 30-day follow-up, there were 6 patients (1.3%; 2 claudicants, 4 CLIs) who underwent TLR and 8 patients who underwent TVR. There were no major amputations in the non-CLI and CLI cohorts. In the CLI cohort, 16/235 (6.8%) underwent minor amputations. Higher stages of Rutherford class and WIfI classification were associated with amputations at 30 days. CONCLUSION: The Phoenix atherectomy system is a safe and effective treatment option in the acute setting for patients with PAD, including those with advanced Rutherford class. Randomized controlled trials are needed to confirm these results.

Long-term clinical outcomes and technical factors with the Wallstent for treatment of chronic iliofemoral venous obstruction.

BACKGROUND: Factors affecting long-term clinical outcome and stent patency after iliofemoral venous stenting remain complex and ill-defined. Also, consensus is lacking among clinicians regarding the continuing role for the Wallstent (Boston Scientific, Marlborough, Mass) as dedicated nitinol-based venous stents become available. We undertook this study to review our long-term results using Wallstents and to evaluate the potential role of this stent in the future. METHODS: From 2007 to 2014, there were 77 limbs in 67 consecutive patients that received Wallstents for chronic iliofemoral vein obstruction. Intravascular ultrasound (IVUS) and venography were used to assess lesion type and extent. Baseline clinical severity was assessed with Venous Clinical Severity Score (VCSS) and Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) classification. Clinical improvement was assessed with VCSS at 12, 24, and 36 months. VCSS change ≥4 points was considered significant improvement. Patency was assessed with duplex ultrasound. A retrospective review of patients' records and imaging was conducted to assess baseline and procedural factors associated with long-term clinical outcomes. RESULTS: Lesions were nonthrombotic in 42 limbs (55%) and left-sided in 48 limbs (62%). Ten patients were treated for bilateral venous disease. Patients were predominantly male (55%); median age was 63 years (range, 47-83 years). Median baseline VCSS was 9 (range, 3-23). IVUS and venography estimated equal vessel compromise length in 37 limbs (48%). IVUS estimated a longer lesion in 32 limbs (42%). Stenting correlated with venography and IVUS in 37 limbs (48%) and more closely aligned with IVUS in 35 limbs (45%). Stents extended into the common femoral vein (CFV) in 17 limbs (22%) and into the inferior vena cava in 6 limbs (8%). Sixty-five (97%) patients had available imaging follow-up (median, 50 months). At 72 months, primary patency in the overall cohort was 87%; assisted primary patency and secondary patency were both 95%. In the nonthrombotic subset, assisted primary patency and secondary patency were 100%; primary patency was 97%. In the post-thrombotic subset, primary patency was 75%; assisted primary patency and secondary patency were 88%. Three early failures occurred. Eight patients required reintervention (range, 0.5-80 months); five interventions were to maintain patency. Cox multivariate regression identified that CFV disease predicted later complications. At last VCSS follow-up per patient (median, 26 months), 52 patients (68%) showed ≥4-point VCSS improvement. None had score worsening. CONCLUSIONS: Venous stenting with Wallstents for iliofemoral post-thrombotic or compressive obstruction proved safe and effective through long-term follow-up, with excellent patency rates. The majority of patients exhibited significant clinical improvement. CFV occlusive disease predicts increased complications.

Detection of early renal transplant rejection by minimally-invasive monitoring of impedance variability.

BACKGROUND: Allograft rejection that occurs after renal transplants is identified by surveillance biopsies or by abnormal laboratory and/or hemodynamic data. The latter are insensitive markers of rejection that may not appear until significant histologic damage has already occurred. Therefore, a sensitive and specific non-invasive method of detecting early rejection of transplanted solid organs is needed. METHOD: A single canine renal allograft was implanted followed by bilateral nephrectomy. Bipolar pacing electrodes were implanted at each end of the transplanted kidney. A second set of electrodes was implanted in the liver, which served as a non-rejecting normal organ. Electrodes were connected to an implantable sensor placed in the subcutaneous tissue. Electrical tissue impedance levels were telemetrically downloaded daily. The clinical status of the transplanted organ was monitored by following the blood urea nitrogen and serum creatinine levels, urine output, and clinical appearance. After tissue impedance levels had stabilized, all immunosuppressants were abruptly discontinued. Clinical signs of rejection were then observed after a few days. RESULTS: Rejection was accompanied by changes in electrical impedance of the implanted organ. These changes, when observed, occurred 1-5 days before clinical signs of rejection appeared. CONCLUSION: Analyses of these data suggest that development of a minimally-invasive high-confidence sensor of early rejection of solid organ transplants is feasible.

Endovascular delivery of vein segments with valves versus direct anastomosis.

PURPOSE: To demonstrate an experimental model designed to allow placement of a vein segment containing a valve into a femoral vein without the need for anastomoses or surgical incision on the target limbs. METHODS: Segments of jugular veins containing valves were harvested bilaterally from 7 female dogs weighing 30 to 40 kg. One of the vein segments was then interposed into one femoral vein, using a standard surgical end-to-end anastomosis. Another segment was loaded into a self-expanding nitinol stent, everted, and secured outside of the stent. This vein-coated stent was then deployed from the jugular approach into the opposite common femoral vein. The endpoint of the study was thrombosis of one of the veins segments or patency at 120 days. The function of the valves was tested prior to completion of the study by instilling dye under incremental pressures and recording the pressure necessary to cause reflux. Light microscopy and electron microscopy were utilized to evaluate structure of the valves at study endpoint. RESULTS: Both grafts in one dog occluded during the second week after surgery. Anastomotic and vein-stented sites remained patent in the remaining 6 animals for 120 days. Retrograde phlebography demonstrated valve competency bilaterally in all cases. The reflux pressures on the stented side averaged 70 mmHg while the transplanted vein segment averaged 55 mmHg. Light microscopy and electron microscopy showed intact vein valve structure in all segments at the completion of the study. CONCLUSIONS: This experimental work demonstrates that endovascular delivery of a native canine vein containing a competent valve is feasible and effective.