Joseph S. Giglia

Mesenteric shunting decreases visceral ischemia during thoracoabdominal aneurysm repair

PURPOSE A technique to decrease visceral ischemic time during thoracoabdominal aneurysm (TAA) repair is reported. METHODS A 10 mm Dacron side-arm graft is attached to the aortic prosthesis and positioned immediately distal to the planned proximal thoracic aortic anastomosis. On completion of the anastomosis, a 16 to 22 Fr perfusion catheter is attached to the side-arm graft and inserted into the orifice of the celiac axis or superior mesenteric artery. The cross-clamp is then placed on the aortic graft distal to the mesenteric side-arm graft. Pulsatile arterial perfusion is thus established to the visceral circulation while intercostal anastomoses or reconstruction of celiac, superior mesenteric, and right renal arteries is performed. Visceral ischemic time and the rise in end-tidal Pco2 after reconstruction of the visceral vessels in patients with mesenteric shunting was compared with a control group matched for aneurysm extent and treated immediately before use of the mesenteric shunt technique. RESULTS Between July and Oct, 1996, the technique was applied in 15 patients undergoing type I, II, or III TAA repair with a clamp and sew technique. The mean decrease in systolic arterial pressure was 12.5 +/- 8.5 mm Hg, with a concomitant rise in end-tidal Pco2 (mean, 6.9 +/- 5.8 mm Hg), after perfusion was established through the mesenteric shunt. Mean time to establishment of visceral perfusion through the shunt was 25.5 +/- 4.4 minutes; the resultant decrement in visceral ischemic time averaged 31.3 minutes (i.e., until celiac, superior mesenteric, and right renal arteries were reconstructed). Compared with controls, patients with shunts had a significantly decreased (6.9 +/- 5.8 versus 21.6 +/- 8.4 mm Hg; p = 0.0003) rise in end-tidal CO2 on completion of visceral vessel reconstruction. CONCLUSIONS In-line mesenteric shunting is a simple method to decrease visceral ischemia during TAA repair, and it is adaptable to clamp and sew or partial bypass and distal perfusion operative techniques.

Back to basics: Use of fresh cadavers in vascular surgery training

BACKGROUND Surgical trainees face many obstacles in learning basic surgical anatomy and technique. Pressure for quicker operative times, introduction of an 80-hour work week, rising numbers of endovascular procedures replacing open surgery, and the presence of fellowship training programs can limit resident exposure not only to surgical skills, but to attending faculty as well. Our goal was to design a vascular exposures course using fresh frozen cadavers to promote dissection and suturing skills, foster interaction with Vascular Surgery faculty, promote teamwork between residents, and measure the satisfaction of the residents with the course. METHODS A pilot program was created with fresh frozen cadavers used to teach basic vascular surgical anatomy and operating skills to junior and mid-level general surgery residents. The course was organized by the Department of General Surgery and the Division of Vascular Surgery. Trainees completed a general questionnaire and evaluation at the completion of the course. RESULTS Forty-five general surgery residents participated in 6 independent sessions offered over a 24-month period. Data from 2 questionnaires were entered into a spreadsheet and analyzed. Eighty-five percent of residents found the course met their expectations. Fresh frozen cadaver material was found optimal by all participants. Forty-four of 45 (97.8%) residents rated the educational value of the course with a perfect score and would recommend the course to others. CONCLUSION Fresh frozen cadavers provide an excellent opportunity to teach basic open vascular surgery principles while fostering interaction with faculty. Sharing cadavers between multiple disciplines can help with cost containment.

PREVENTION OF SPINAL CORD ISCHAEMIC COMPLICATIONS AFTER THORACOABDOMINAL AORTIC SURGERY

Since the publication of prior reviews on this topic, substantial clinical experience with a variety of operative strategies to prevent ischaemic cord complications has been reported. The available data on angiographic localisation of critical intercostal vessels, and, in particular, the evoked potential response to cross-clamping in patients indicates that risk of paraplegia varies considerably even among patients with equivalent TAA extent. Factors such as individual development of the ASA, patent critical intercostals, and the particulars of collateral circulation when intercostal aortic ostia are already occluded likely account for this variability. Information available from SSEP monitoring relative to the dynamic course of cord ischaemia with cross-clamping, and the parallel, if not, frustrating experience with angiographic localisation and intercostal vessel reconstruction indicates that a narrow temporal threshold of cord ischaemia with clamping is present in many patients. This reinforces the importance of both expeditious clamp intervals, critical intercostal re-anastomoses, and the desirability of neuroprotective manoeuvres during cross-clamp induced cord ischemia. As suggested in compelling experimental work our contemporary clinical experience, and predicted by prior reviewers, regional cord hypothermia provides significant promise for limiting or eliminating, in particular, immediate perioperative deficits. Avoidance of postoperative hypotension, spinal cord oedema, and preservation of critical intercostal vessels are additional strategies necessary to impact the development of delayed deficits favourably.

Evaluation of the redesigned conformable GORE TAG thoracic endoprosthesis for traumatic aortic transection

OBJECTIVE To evaluate the safety and effectiveness of the conformable GORE TAG thoracic endoprosthesis (CTAG) device (W. L. Gore and Associates, Flagstaff, Ariz) for the endovascular repair of traumatic aortic transections. METHODS A prospective, nonrandomized, multicenter trial was conducted at 21 sites. Primary safety end points included 30-day all-cause mortality. The effectiveness end point was freedom from a major device event requiring reintervention through 1-month follow-up. RESULTS Fifty-one subjects were enrolled between December 2009 and January 2011 with polytraumatic injuries and a mean Injury Severity Score of 32 ± 14. The proximal mean intimal aortic diameter measured 24 mm, while the mean distal intimal diameter was 22 mm. A total of 57 CTAG devices were implanted (mean, 1.1/subject; range, 1-2) with a mean patient age of 44 years (range, 21-87) and a male-to-female ratio of 2:1. Technical success was 100% with an operative mortality of 0%. Femoral access was utilized in 96% of patients. The mean procedure time and blood loss was 105 minutes and 148 mL, respectively. All subjects required admission to an intensive care unit with a mean hospital stay of 14.6 days. Adjuvant techniques (ie, lumbar drains and induced hypertension) to prevent paraplegia were used in only 7.8% of patients. No patient developed paraplegia despite 63% having complete or partial left subclavian artery coverage and only 9% of those receiving left subclavian artery revascularization. In addition, there were no device compressions or major device events reported. Overall mortality at 30 days was 7.8%, and all were adjudicated by the clinical events committee as not being device or procedure related. Serious adverse events occurred in 39.2% of patients through 30 days. To date, there have been no conversions to open repair. Two site-reported endoleaks were detected during the mean follow-up of 4.2 months, which did not require reintervention. CONCLUSIONS The CTAG device was demonstrated to be a safe and effective treatment for traumatic aortic transection based on 30-day outcomes. There were no device-related serious adverse events.

Prevention of paraplegia during thoracic aortic cross-clamping: Importance of patent internal mammary arteries

PURPOSE Unexplained anatomic and physiologic factors account for the unacceptably high rate of paraplegia/paresis after thoracoabdominal aortic reconstruction. We assessed the neurologic significance of patent internal mammary arteries (IMAs) in a novel rat model of aortic clamping in which the aortic origins of the intercostal arteries (ICAs) were occluded. METHODS Twenty anesthetized, intubated, and halothane-ventilated adult male rats had catheters placed in the carotid and femoral arteries. ICAs arising from the aorta were divided at their origins through a left thoracotomy. IMAs were either divided (IMA-OUT, n = 10) or left intact (IMA-IN, n = 10). Proximal and distal descending aortic clamps were placed for 7 minutes. A neurologic deficit score (NDS) was assigned at 1, 4, 18, 24, and 48 hours by use of an established scoring system. RESULTS The mean IMA-IN NDS was statistically better than the mean IMA-OUT NDS at 1, 4, 18, and 24 hours with p = 0.0005, 0.0014, 0.0098, and 0.0151, respectively. Moreover, the mortality rate in the IMA-OUT group was statistically greater than in the IMA-IN group (p = 0.0036). CONCLUSION In this model, patent IMAs prevent paraplegia when the ICAs are occluded at their aortic origin and the aorta is clamped for 7 minutes.

Endovascular repair for blunt thoracic aortic injury using the Zenith Alpha low-profile device

OBJECTIVE The objective of this study was to report 30-day results from a prospective, nonrandomized, multicenter trial that evaluated the safety and effectiveness of the Zenith Alpha thoracic endovascular graft (Cook Medical, Bloomington, Ind) for treatment of blunt thoracic aortic injuries (BTAIs). METHODS Eligible patients with BTAIs (grade II to grade IV) in the descending thoracic aorta were treated with the Zenith Alpha device, which is available in smaller graft diameters (starting at 18 mm) and lower profile delivery systems (starting at 16F) than currently available thoracic endografts. The device (nitinol stents and polyester graft material) accommodates a tighter aortic curvature (radius of 20 mm) than the predicate Zenith TX2 Pro-Form. Follow-up clinical and imaging evaluations were performed at 30 days, at 6 and 12 months, and annually thereafter through 5 years. The primary end point was 30-day mortality. RESULTS Between January 2013 and May 2014, 50 patients (44 men; mean age, 43 ± 19 years; range, 18-89 years) were treated with the Zenith Alpha device at 17 U.S. sites. The mean Injury Severity Score was 31 ± 14 (range, 3-66). Technical success was achieved in 100% of patients, with 0% intraoperative mortality. Device access was entirely percutaneous in 22 patients (44%). Smaller size grafts (18-24 mm) were used in 15 patients (30%). The mean procedure time was 85 ± 44 minutes (range, 34-278 minutes), and mean blood loss was 103 ± 145 mL (range, 0-1000 mL). The 30-day mortality rate was 2%; one patient died 24 days after the procedure of respiratory failure related to associated injuries and not to the device or procedure as adjudicated by an independent Clinical Events Committee (CEC). One patient experienced a stroke 7 days after the procedure (cause undetermined by the CEC), and one patient underwent reintervention for a site-reported proximal type I endoleak (core laboratory reported unknown endoleak type) at 30 days after the procedure. There have been no conversions to open surgical repair, paraplegia, or aortic rupture within 30 days. CONCLUSIONS Short-term results indicate that the Zenith Alpha thoracic endovascular graft appears safe and effective for the treatment of BTAIs. This low-profile device enables complete percutaneous repair in a large percentage of patients and can achieve high rates of technical success and very low rates of aortic injury-related mortality within 30 days.

Clinical Outcomes of Obturator Canal Bypass

Objective: Infected aortofemoral grafts pose a formidable challenge with a significant risk of limb loss and high mortality. Despite successful reports of obturator canal bypass (OCB) for infected aortofemoral graft and complicated groins, the technique has not gained widespread use. We reviewed our experience with OCB and performed a systematic review of the literature. Methods: A retrospective review of patients who underwent OCB in our institution between 1995 and 2013 was conducted. Demographics of the patients, comorbidities, previous interventions, and postoperative and longer term related events were recorded. Outcomes were primary and secondary patency, limb salvage, and survival rates. For the literature review, all published series in the English language were identified through a PubMed database query. Results: Fifteen patients underwent 18 OCBs during the study period. Mean age was 59.6 ± 12 years, and 11 were men. Indications for surgery were chronic infection in 10 patients and acute bleeding in 5. Polytetrafluoroethylene was used in all cases. Mean clinical follow‐up was 57.7 ± 42.3 months (range, 7.4‐181). The 30‐day complications included three (16.7%) superficial wound infections without any cardiac events, stroke, or death. Midterm outcomes included five late deaths and one myocardial infarction. Regarding major adverse limb events, three patients underwent above‐knee amputation. Another procedure was required in 11 of the 18 limbs (61%) at a mean duration of 42 months for reoperation and 35 months for reintervention. One OCB (6%) became infected, requiring removal at 42 months. Primary, primary assisted, and secondary patency was 65%, 71%, and 88% at 24 months, respectively. Overall survival and limb salvage was 83% and 81% at 36 months, respectively. Conclusions: The OCB can be performed safely with minimal early morbidity and mortality in well‐selected patients with infections limited to one femoral anastomosis site. Limb salvage and overall mortality in this series are excellent and in agreement with the reported literature on OCB. Long‐term follow‐up is recommended because of a significant reoperation and reintervention rate.

Contemporary outcomes for ruptured abdominal aortic aneurysms using endovascular balloon control for hypotension

Objective: Ruptured abdominal aortic aneurysm (rAAA) continues to portend significant mortality, despite ruptured endovascular aneurysm repair (rEVAR), enhanced perioperative care, and endovascular balloon control (EBC) for hypotension. We review our academic institutions experience using a protocol of EBC for all hypotensive patients, irrespective of type of repair. Methods: A retrospective review was conducted of 66 cases of rAAA treated at a single academic institution from 2007 to 2016 using EBC for hypotensive patients. Demographics, comorbidities, intraoperative parameters, and clinical outcomes were recorded. Patients were studied with respect to hemodynamic status, rEVAR, or ruptured open aortic repair in the setting of EBC for hypotension. Results: rEVAR was performed in 43 patients (65%) and ruptured open aortic repair in 23 patients (35%). rAAA was treated in 51 men (77%). Mean rAAA size was 7.6 mm, and mean age of the patients was 73 years. Perioperative survival was 82%. Overall survival at 30 days, 1 year, and 5 years was 71%, 65%, and 52%. Blood transfusion and severe hypotension were significant predictors of mortality at 30 days on multivariable analysis (odds ratio of 1.2 [P = .08] and 39 [P = .03], respectively). Severe hypotension was defined as a mean arterial blood pressure <65 mm Hg and vasopressor use and was present in 59% of the cohort. Normotension was defined as an absence of these conditions and was present in 12%, with 29% of patients exhibiting moderate hypotension. There was no difference in 30‐day survival between normotensive and moderately hypotensive patients. The 30‐day survival for severely hypotensive patients was 61% vs 85% for moderately hypotensive patients (P = .003), with a significant difference between groups that persisted at 1 year (85% vs 51%; P = .008) and 5 years (66% vs 51%; P = .017). Conclusions: Good midterm outcomes for moderately hypotensive and normotensive patients can be obtained using an EBC protocol for hypotension with a regionalized transport system directly to the operating room. Severely hemodynamically unstable rAAA patients still pose a significant challenge despite mitigation of hypotension by EBC, suggesting that survival may be compromised by factors other than hypotension alone. We still advocate for the use of EBC for all hypotensive patients as part of a defined rAAA protocol before definitive repair.

Novel Use of a Gastrointestinal Stapler for Diaphragm Division During Thoracoabdominal Aortic Exposure

A significant portion of the morbidity associated with a thoracoabdominal approach to the suprarenal aorta is due to postoperative pulmonary dysfunction. A contributing factor to this dysfunction is division of the diaphragm during surgical exposure and subsequent repair upon completion of the operation. In this brief technical report, we describe a novel technique using a gastrointestinal stapler to divide the diaphragm that is rapid, hemostatic, and aids with reapproximation at the completion of the case. This method of diaphragm division is quicker and less traumatic and has the potential to decrease the incidence of postoperative pulmonary dysfunction.

Extra-anatomic Revascularization

In the presence of severe unilateral iliac occlusive disease that is not amenable to endovascular therapy, revascularization can be accomplished via an extraanatomic route by performing a crossover femorofemoral bypass originating from the contralateral limb. The donor limb should not suffer untoward effects from the extra-anatomic revascularization even in the presence of infrainguinal disease unless proximal hemodynamic stenoses were missed or left untreated. If the donor inflow is marginal due to the presence of proximal disease in its iliac system, endovascular therapy is used to correct the proximal pathology. This can be performed a few days prior to the extra-anatomic revascularization, typically when the pathology is identified on preoperative angiography. Alternatively, the endovascular therapy can be performed simultaneously during the construction of the femoro-femoral bypass especially if magnetic resonance angiography or CT angiography was used for preoperative evaluation.