Peter Mossop

Prospective multicenter clinical trial (STABLE) on the endovascular treatment of complicated type B aortic dissection using a composite device design.

OBJECTIVE This study evaluates the safety and effectiveness of a unique composite thoracic endovascular aneurysm repair (TEVAR) construct (proximal stent graft and distal bare metal stent) for the treatment of patients with complicated type B aortic dissection (cTBAD). METHODS In this prospective, single-arm, multicenter study, patients with cTBAD were treated with an endovascular system consisting of proximal TX2 thoracic stent grafts and distal bare metal dissection stents (Zenith Dissection Endovascular System; Cook Medical, Bloomington, Ind). Indications for enrollment were branch vessel malperfusion, impending rupture, aortic diameter ≥40 mm, rapid aortic expansion, and persistent pain or hypertension despite maximum medical therapy. One-year follow-up results, including clinical and radiographic (computerized tomography [CT] and X-ray) evaluation, were available for this report. RESULTS Ten centers enrolled 40 patients (70% men; mean age 58 years old) between December 2007 and August 2009. The onset of symptoms was acute (≤14 days) in 24 patients (60%), subacute (15-30 days) in six patients (15%), and chronic (31-90 days) in 10 patients (25%); the overall mean time from symptom onset to treatment was 20 days (range, 0-78 days). A majority of patients (77.5%; 31 of 40 patients) presented with impending aortic rupture (indicated by periaortic effusion/hematoma) or branch vessel malperfusion. Seven combinations of stent grafts and dissection stents were used, and all devices were successfully deployed and patent. The 30-day mortality rate was 5% (2 of 40); two deaths occurred after 30 days, leading to a 1-year survival rate of 90%. Two deaths, occurring at 11 and 81 days postprocedure, respectively, were secondary to aortic rupture. Morbidity occurring within 30 days included stroke (7.5%), transient ischemic attack (2.5%), paraplegia (2.5%), retrograde progression of dissection (5%), and renal failure (12.5%). Additional morbidity after 30 days included one case of retrograde progression of dissection and one case of renal failure. None of the patients with renal failure became dialysis-dependent. Four patients (10%) underwent secondary interventions within 1 year. Favorable aortic remodeling was observed during the course of follow-up, indicated by an increase in the true lumen size and a concomitant decrease in the false lumen size along the dissected aorta, with completely thrombosed thoracic false lumen observed in 31% of patients at 12 months as compared to 0% at baseline. CONCLUSIONS Initial data with a composite TEVAR construct have demonstrated favorable clinical and anatomic results. Continued enrollment and long-term data are needed to assess the overall effectiveness of this treatment strategy.

Endovascular repair of an aortoenteric fistula in a high-risk patient.

Purpose: To describe the endovascular repair of an aortoenteric fistula in a high-risk patient. Methods and Results: A Vanguard tube stent-graft was deployed at the upper anastomotic suture line of a secondary aortoenteric fistula, successfully sealing the communication between the aorta and the third part of the duodenum without occlusion of the renal arteries. Conclusions: Endovascular stent-graft repair of aortoenteric fistulae is possible, but further evaluation of this technique will determine its role in the management of this complication.

Staged endovascular treatment for complicated type B aortic dissection

Background A 40-year-old man presented with acute chest and back pain, hypertension and anuria. Two years previously he had been diagnosed with acute uncomplicated type B aortic dissection. Following conservative management, with aggressive antihypertensive therapy and analgesia, he was monitored with 6-monthly surveillance CT scans. These demonstrated a complicated type B dissection with renal and iliac malperfusion.Investigations Multislice CT, transthoracic and transesophageal echocardiography, digital subtraction aortography.Diagnosis Acute-on-chronic type B aortic dissection, complicated by aneurysmal dilatation of the thoracic aorta and visceral malperfusion.Management Antihypertensive therapy; staged thoracoabdominal and branch vessel endoluminal repair (STABLE procedure), with stabilization of the dissection and rescue of renal function; CT imaging surveillance to monitor for any further complications.

TREATMENT OF TRAUMATIC FALSE ANEURYSM OF THE THORACIC AORTA WITH ENDOLUMINAL GRAFTS

PURPOSE Traumatic false aneurysms of the thoracic aorta presenting at a time remote from the original injury are a rare but complex problem. The treatment of a traumatic false aneurysm by endovascular techniques may offer many advantages over conventional open surgery. METHODS AND RESULTS Two male patients presented with traumatic false aneurysm of the thoracic aorta after being treated emergently for visceral injuries from a gunshot wound in one and an automobile accident in the other. In both cases, the aneurysm was situated so that only the T11 intercostal artery would be sacrificed by endoluminal exclusion. Commercially available endoluminal stent-grafts (Talent) were deployed successfully. Recovery in both patients was rapid and uneventful with no neurological sequelae. Spiral computed tomographic scans at 1 year indicated sustained aneurysm exclusion and satisfactory endograft position. CONCLUSIONS A customized endoluminal stent-graft can be used with great accuracy to exclude thoracic false aneurysms, avoiding the potential complexity and morbidity of an open thoracic approach.

Controlled blunt microdissection for percutaneous recanalization of lower limb arterial chronic total occlusions: a single center experience.

Background: Percutaneous techniques for the revascularization of symptomatic lower limb arterial chronic total occlusions (CTOs) remain suboptimal due to difficulty in safely and reliably crossing these heavily calcified lesions using standard guidewire and balloon technology. Objectives: The objective of this prospective study was to evaluate the technical success and safety of controlled blunt microdissection (CMD) for the treatment of resistant peripheral CTOs. Methods: This series enrolled 36 patients (26 men; mean age 67 ± 12 years), with 44 symptomatic CTOs (2 terminal aortic, 24 iliac, 16 femoral, and 2 popliteal), which had previously failed conventional percutaneous revascularization. CMD was carried out using a specialized prototype catheter. Actuation of the hinged jaws of this CMD catheter created a channel within the occluded arterial segment for guidewire passage, and subsequent angioplasty and stenting using standard procedures. The problem of subintimal CMD catheter passage, creating an eccentric channel, was addressed using a second novel device, the true‐lumen reentry (LRE) catheter, which allowed reentry into the downstream lumen. Results: Procedural success, evaluated angiographically, was achieved in 40 (91%) of the 44 CTOs. Fourteen (35%) of these 40 successful recanalizations required guidewire redirection, using the LRE catheter for lesion traversal. There were no complications related to CMD per se; although one patient experienced acute in‐stent thrombosis, managed successfully with intra‐arterial thrombolysis. Conclusions: We therefore conclude that CMD can be used safely and successfully to facilitate recanalization of resistant CTOs in the pelvic and lower limb arteries.

Aortic remodeling after endovascular treatment of complicated type B aortic dissection with the use of a composite device design

OBJECTIVE The purpose of this study is to report updated clinical and aortic remodeling results from the Study for the Treatment of complicated Type B Aortic Dissection using Endoluminal repair (STABLE) trial, a prospective, multicenter study evaluating safety and effectiveness of a pathology-specific endovascular system (proximal stent graft and distal bare metal stent) for the treatment of complicated type B aortic dissection. METHODS All 86 enrolled patients (mean age, 59 years; 73.3% men) were treated within 90 days of symptom onset (55 with acute dissections and 31 with nonacute dissections). Inclusion criteria were branch vessel obstruction/compromise, impending rupture as evidenced by periaortic effusion/hematoma, resistant hypertension, persistent pain/symptoms, or aortic growth ≥5 mm within 3 months (or transaortic diameter ≥40 mm). Remodeling of the dissected aorta, including thrombosis of the false lumen and changes in the true lumen, false lumen, and transaortic diameter, were assessed in patients with available computed tomographic imaging through 2 years. RESULTS The 30-day mortality rate was 4.7% (4/86) in the overall patient group (5.5% in acute patients and 3.2% in non-acute patients). Freedom from all-cause mortality was 88.3% at 1 year and 84.7% at 2 years (no significant difference between acute and nonacute patients). From baseline to 2 years, the true lumen diameter increased significantly in the descending thoracic aorta and the more distal abdominal aorta, along with a decrease in the false lumen diameter in both aortic segments. A majority of patients had either a stable or shrinking transaortic diameter in the thoracic (80.3% at 1 year and 73.9% at 2 years) or abdominal aorta (79.1% at 1 year and 66.7% at 2 years). Transaortic growth (>5 mm) occurred predominantly in acute dissections. Consistently, a shorter time from symptom onset to treatment was found to predict transaortic growth in the abdominal aorta (P = .03). CONCLUSIONS Endovascular repair of complicated type B aortic dissection with the use of a composite construct demonstrates favorable early clinical outcomes and aortic remodeling. However, patients treated in the acute setting may be prone to aortic growth and may require close observation. Follow-up through 5 years is ongoing.

Intraluminal blunt microdissection for angioplasty of coronary chronic total occlusions

This study describes a new approach to crossing coronary chronic total occlusions using controlled blunt microdissection and its successful application to coronary angioplasty in three patients. After guidewire techniques failed to cross the occlusions, the blunt intraluminal microdissection catheter was deployed. Actuation of a hinged jaw on the catheter distal assembly created a channel for the guidewire through the diseased segment, in the true lumen (a right coronary and a left circumflex artery) and subintimally (a circumflex artery), to allow angioplasty and stenting. Coronary circulation improved from TIMI grade 0 to 3. Angina was relieved in all three cases. Subsequent angiography for two cases, 2 and 19 months after PTCA, respectively, showed restored flow and patent stented regions. Cathet Cardiovasc Intervent 2003;58:194–198.

Combined Proximal Endografting With Distal Bare-Metal Stenting for Management of Aortic Dissection

BACKGROUND Established endovascular treatments for aortic dissection often result in incomplete aortic repair, potentially leading to late complications involving the distal aorta. To address the problems of incomplete true lumen reconstitution and late aneurysmal change, we report the midterm results of combined proximal endografting with distal true lumen bare-metal stenting (STABLE: Staged Total Aortic and Branch vesseL Endovascular reconstruction) in Stanford type A and B aortic dissection. METHODS Between January 2003 and January 2010, 31 patients underwent staged total aortic and branch vessel endovascular reconstruction for management of acute (type A, 13; type B, 11) and chronic (type B, 7) aortic dissection. Proximal endografting was combined with bare-metal Z stent implantation in the distal true lumen. Patients with type A dissection underwent adjunctive treatment at operation. Computed tomography angiography was performed at baseline, 1 year, and annually thereafter to assess aortic remodelling. RESULTS Primary technical success was 97%. Thirty-day rates of death, stroke, and permanent paraplegia/paresis were 3% (n=1), 0%, and 0%, respectively. Mean follow-up was 57.3 months (range, 5 to 100 months). Overall survival was 60% at 100 months. Aortic-specific survival was 93%. Four patients (13%) underwent device-related reintervention. One (3%) late aortic-related death occurred. Thoracic (p=0.64) and abdominal (p=0.14) aortic dimensions were stable. The true lumen index increased significantly at follow-up. CONCLUSIONS Staged total aortic and branch vessel endovascular reconstruction is a feasible ancillary endovascular technique to address the problems of distal true lumen collapse, incomplete aortic remodelling, and late aneurysm formation in aortic dissection.

First case reports of controlled blunt microdissection for percutaneous transluminal angioplasty of chronic total occlusions in peripheral arteries.

Percutaneous transluminal angioplasty (PTA) can fail to revascularize peripheral arteries when a chronic total occlusion (CTO) cannot be crossed by guidewires. This article describes application of a new controlled blunt microdissection (CMD) catheter designed to cross CTOs. Two men presenting with severe claudication had iliac CTOs that resisted crossing with guidewires. Using standard techniques, the CMD catheter was advanced to the CTO. Following attempts to cross the CTO with guidewires, the jaw of the CMD distal assembly was actuated, advancing through the CTO as plaque was blunt‐dissected. After angioplasty and stenting, restored distal flow was restored. Ischemic symptoms had not recurred at 1‐ and 28‐month follow‐up. The concept of blunt intraluminal microdissection has been applied to convert failing to successful PTA of peripheral arteries. CTOs that had resisted guidewire crossing were successfully crossed using the CMD catheter, allowing treatment by angioplasty and stenting. Cathet Cardiovasc Intervent 2003;59:255–258.

Reduced cardiac output is associated with decreased mitochondrial efficiency in the non-ischemic ventricular wall of the acute myocardial-infarcted dog.

Cardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction (MI). Understanding the mechanisms for acute pump failure is therefore important. The aim of this study is to examine in an acute MI dog model whether mitochondrial bio-energetic function within non-ischemic wall regions are associated with pump failure. Anterior MI was produced in dogs via ligation of left anterior descending (LAD) coronary artery, that resulted in an infract size of about 30% of the left ventricular wall. Measurements of hemodynamic status, mitochondrial function, free radical production and mitochondrial uncoupling protein 3 (UCP3) expression were determined over 24 h period. Hemodynamic measurements revealed a > 50% reduction in cardiac output at 24 h post infarction when compared to baseline. Biopsy samples were obtained from the posterior non-ischemic wall during acute infarction. ADP/O ratios for isolated mitochondria from non-ischemic myocardium at 6 h and 24 h were decreased when compared to the ADP/O ratios within the same samples with and without palmitic acid (PA). GTP inhibition of (PA)-stimulated state 4 respiration in isolated mitochondria from the non-ischemic wall increased by 7% and 33% at 6 h and 24 h post-infarction respectively when compared to sham and pre-infarction samples. This would suggest that the mitochondria are uncoupled and this is supported by an associated increase in UCP3 expression observed on western blots from these same biopsy samples. Blood samples from the coronary sinus measured by electron paramagnetic resonance (EPR) methods showed an increase in reactive oxygen species (ROS) over baseline at 6 h and 24 h post-infarction. In conclusion, mitochondrial bio-energetic ADP/O ratios as a result of acute infarction are abnormal within the non-ischemic wall. Mitochondria appear to be energetically uncoupled and this is associated with declining pump function. Free radical production may be associated with the induction of uncoupling proteins in the mitochondria.