Houssam K. Younes

Hybrid thoracic endovascular aortic repair: Pushing the envelope

OBJECTIVE Thoracic endovascular aortic repair (TEVAR) can be limited by inadequate proximal and distal landing zones. Debranching or hybrid TEVAR has emerged as an important modality to expand landing zones and facilitate TEVAR. We report a single-center experience with hybrid TEVAR. METHODS We retrospectively reviewed all patients with thoracic aortic disease who received a TEVAR between February 2005 and October 2008. RESULTS Forty-two patients underwent a hybrid procedure (mean age 68 +/- 13 years; 55% men). All patients were denied open surgery due to preoperative comorbidities or low physiologic reserve; 62% had a history of coronary artery disease, 67% had chronic obstructive pulmonary disease, 61% had undergone prior aortic surgery, and 90% had an American Society of Anesthesiology score of 4 and above. The average Society for Vascular Surgery comorbidity score was 12 +/- 2 with a range of 9 to 14. Fifty-five percent of cases were symptomatic on presentation and 83% were done emergently. Seventy-six percent underwent debranching of the aortic arch, 17% of the visceral vessels, and 7% required both. Primary technical success was achieved in all cases and of these, 43% were staged. The 30-day mortality was 5%. Myocardial infarction developed in 5%, respiratory failure in 31%, cerebrovascular accident (stroke or transient ischemic attack) in 19%, and spinal cord ischemia with ensuant paraplegia occurred in 5% of patients. Fifty-eight percent of patients were discharged home, 11% required rehabilitation, and 29% were transferred to a skilled nursing facility. There was a significant association between visceral vessel debranching and both spinal cord ischemia (P = .004) and gastrointestinal complications (P = .005). On the other hand, there was no difference between staged and non-staged hybrid procedures. CONCLUSIONS Hybrid procedures can successfully extend the range of patients suitable for a subsequent TEVAR. These procedures are associated with higher complication rates than isolated infrarenal or thoracic endovascular repair, but given the medical and anatomical complexity of these patients, the current results are quite encouraging.

A Computational Fluid Dynamics Study Pre- and Post-Stent Graft Placement in an Acute Type B Aortic Dissection

Purpose: To demonstrate the capability of computational fluid dynamics (CFD) for quantifying hemodynamic forces pretreatment/posttreatment in type B aortic dissection (TB-AD). Methods: From CFD simulations initialized with dynamic magnetic resonance image data, wall shear stress (WSS) and dynamic pressure (dynP) changes post endovascular treatment were quantified. Results: After 1 year follow-up, thoracic aortic segment was completely remodeled, and persistent, nonthrombosed false lumen in the abdominal aorta was noted. Pretreatment, large WSS (>5 Pa) and dynP (>80 Pa) occurred at entrance tear and a stenotic region in the true lumen (TL). Posttreatment, WSS was lower than 3.3 Pa and dynP was lower than 55 Pa in TL, except at proximal end of the stent graft and at reentrance tear. Two focal locations of high dynP existed within the stent graft. Conclusions: Computational fluid dynamics may provide quantitative assessment of hemodynamic wall forces in TB-AD potentially of interest for follow-up examinations.

Thoracic Endovascular Aortic Repair for Type B Aortic Dissection

BACKGROUND Thoracic endovascular aortic repair (TEVAR) has emerged as an acceptable off-label treatment modality for aortic dissection. We report our experience in endovascular treatment of this disease with an emphasis on defining the patterns of morbidity. METHODS We retrospectively reviewed all (n = 90) patients with thoracic aortic disease who received a TEVAR between February 2005 and December 2007. Aortic dissection was the indication in 23 (26%) patients (48% acute, 52% chronic; Stanford A 17%, Stanford B 83%). For the purposes of this report, we concentrated on the type B dissection (17 patients). Eighty-two percent of the patients were symptomatic on presentation, and 56% of cases were performed either urgently or emergently. RESULTS Technical success was achieved in 100% of cases, with an average operative time of 178 + or - 119 min. Forty-seven percent required a left subclavian bypass. Thirty-day mortality was 5.5% and morbidity was 12%. Postoperative complications included respiratory failure in 28% of cases, gastrointestinal symptoms in 11%, and cerebrovascular symptoms in 5.5%. No renal failure occurred. While cerebrospinal fluid drain was used in 35% of cases, transient spinal cord ischemia was observed in 5.5%. Average length of stay was 13 + or - 12 days; 63% of patients were discharged home, 12% required rehabilitation, and 25% were discharged to a skilled nursing facility. There was no association between outcome and mode of presentation or anatomic extent. CONCLUSION Aortic dissection remains a challenging clinical entity, and the advent of TEVAR has improved outcomes but still carries considerable morbidity, with distinct patterns between mode of presentation and anatomic extent.

Retrograde transpopliteal access is safe and effective - It should be added to the vascular surgeon's portfolio

BACKGROUND The aim of the study was to review the outcomes of superficial femoral artery (SFA) interventions using a retrograde transpopliteal access approach after failed antegrade recanalization. METHODS A database of patients undergoing endovascular treatment of the SFA between 2008 and 2011 was retrospectively queried, and those cases with transpopliteal artery retrograde access were analyzed. Time-dependent outcomes were determined by Kaplan-Meier survival analyses. RESULTS A total of 16 patients (75% men; mean age 61 ± 9 years) underwent retrograde popliteal access after failed antegrade attempts. Patients had multiple cardiovascular comorbidities with a mean modified cardiac index score of 3.1 ± 1.8. The reason for intervention was lifestyle-limiting claudication in 67% of cases and critical ischemia in the remainder. Most of the lesions were Trans-Atlantic Inter-Society Consensus II C and D. Retrograde ultrasound-guided puncture of the popliteal artery was successful in all cases and there were no local site complications. Intervention was successful in 94% of cases. One uncomplicated perforation (7%) was encountered during attempted recanalization of the SFA in the thigh. There was no perioperative morbidity or 30-day mortality. The 30-day major adverse cardiovascular events rate was 6% but both 30-day major adverse limb events and the 30-day major amputation rate were 0%. There was a 40% increase in actual ankle-brachial index (ABI); 93% of patients achieved an ABI rise >0.15. On longer term follow-up, 2 patients developed restenosis and 1 an asymptomatic occlusion. Both restenosis patients required re-angioplasty. Two patients required expected toe amputations as a result of their presenting symptoms. The primary patency was 66 ± 9%, assisted patency 81 ± 9%, and secondary patency 87 ± 8% at 2 years. Limb salvage was 100%. Clinical efficacy was 63 ± 9% at 2 years. CONCLUSIONS Ultrasound-guided retrograde transpopliteal access is a safe and successful technique, which extends the ability to perform endovascular interventions after failed antegrade approaches.

An image processing algorithm for the in-vivo quantification and visualization of septum motion in type III B - aortic dissections with cine magnetic resonance imaging

Currently, there is no method to predict outcome of endovascular treatment (EVAR) of type III B aortic dissections (TB-AD). A new image processing algorithm is presented for quantifying IS displacement from cine 2D phase contrast magnetic resonance images (2D pcMRI) towards a new classification of TB-AD based on IS mobility Bulk motion of the true aortic lumen (tAB) center (ALC), maximum, minimum and average displacement of the boundary points composing the IS and tAB excluding the IS were quantified at two locations in one patient. Correlations of the ALC motion and the averaged temporal displacement AD(t) of IS and tAB excluding IS with the aortic flow waveform were calculated. Range of ALC motion was similar in both locations (average 0.56 mm, max 1.37 mm) and correlated with the aortic flow waveform in the abdominal aorta but not the thoracic aorta. Range of displacement of the IS was from 1.27 mm to -1.64 mm (average 0.09 ± 0.07 mm) in the thoracic aorta, and from 0.38 mm to -3.38 mm (average 0.42 ± 0.23 mm) in the abdominal aorta. tAB motion excluding the IS was 1.21 mm to 0.84 mm (thoracic, average 0.13 ± 0.07 mm) and 0.52mm to -1.88 mm (abdominal, average 0.37 ± 0.11 mm). AD(t) for IS and tAB excluding the IS both correlated with aortic flow in the abdominal aorta only.

Spontaneous regression of an abdominal aortic aneurysm in an immunocompromised patient.

Spontaneous aneurysmal regression is a rare event, having been observed only in association with arteritides or immunosuppression following solid-organ transplantation. In particular, the spontaneous regression of an aortic aneurysm, to our knowledge, has never been documented. We report a case of a 46-year-old, HIV-positive, African-American man who developed an asymptomatic juxtarenal abdominal aortic aneurysm, which significantly regressed over a 6-month period in the absence of arteritides or systemic immunosuppressive therapy. This case describes the spontaneous regression of an inflammatory AAA in an HIV-positive patient. Further studies will be required to determine if this was an isolated occurrence or if it occurs with any frequency in specific patient populations.

Inferior Mesenteric Artery Duplex in the Management of Chronic Mesenteric Ischemia

Introduction Duplex interrogation of the mesenteric arteries is a frequent practice during the workup of chronic mesenteric ischemia (CMI). We report a case in which duplex ultrasound identified a stenosis of the inferior mesenteric artery (IMA) that was not initially detected on either angiogram or computed tomography angiography (CTA). Case Report A 72-year-old Hispanic man with a history of CMI presented with a 1-week history of vague postprandial abdominal pain that became severe and constant during the last 3 days. The patient was admitted and an aortic angiogram was performed, demonstrating a normal celiac axis and IMA, and short segment superior mesenteric artery (SMA) occlusion with reconstitution via a large meandering branch of the IMA. Aortic duplex was also performed that confirmed the occlusion of the SMA and demonstrated significant velocity elevation (>450 mm/sec) with color flow disturbances suggestive of high-grade stenosis at the origin of the IMA. This duplex ultrasound finding prompted further investigation with CTA of the abdomen and pelvis, which demonstrated a high-grade stenosis of the celiac axis, occlusion of the SMA, and an atherosclerotic plaque in the infrarenal aorta near the origin of the IMA without evidence of stenosis. Because of the patients persistent abdominal symptoms and disparate imaging results, a repeat angiogram with multiple views was able to identify both the celiac and IMA stenoses, each of which was successfully treated with stents. The patients abdominal symptoms resolved within 4 days. Three months after stenting, the patient remains symptom free, and a follow-up duplex examination showed patency of both the celiac artery and IMA stents. Conclusion Multiple imaging modalities are often essential in the work up for patients with CMI. This case demonstrates the sensitivity of duplex ultrasound in the identification of an IMA stenosis in a patient with a known occlusion of the SMA, and not initially identified on the angiogram or CTA.