Francisco C. Albuquerque

Stroking human jejunal mucosa induces 5-HT release and Cl− secretion via afferent neurons and 5-HT4receptors

5-Hydroxytryptamine (5-HT) release and neural reflex pathways activated in response to mucosal stroking were investigated in muscle-stripped human jejunum mounted in modified Ussing chambers. The mucosa was stroked with a brush at 1/s for 1-10 s. Mucosal stroking resulted in a significant increase in the concentration of 5-HT in the mucosal bath within 5 min. It also was associated with a reproducible positive change (Δ) in short-circuit current ( I sc), which was abolished by inhibitors of chloride secretion. Capsaicin and hexamethonium significantly inhibited the Δ I sc but not the release of 5-HT. The Δ I sc was inhibited by TTX but not by atropine. It was also inhibited by the 5-HT3,4 receptor antagonist tropisetron (10 μM) and the 5-HT4,3 receptor antagonist SDZ-205-557 (10 μM) but not by preferential antagonists of 5-HT1P, 5-HT2A, or 5-HT3 receptors. These results suggest that mucosal stroking induces release of mucosal 5-HT, which activates a 5-HT4 receptor on enteric sensory neurons, evoking a neuronal reflex that stimulates chloride secretion.5-Hydroxytryptamine (5-HT) release and neural reflex pathways activated in response to mucosal stroking were investigated in muscle-stripped human jejunum mounted in modified Ussing chambers. The mucosa was stroked with a brush at 1/s for 1-10 s. Mucosal stroking resulted in a significant increase in the concentration of 5-HT in the mucosal bath within 5 min. It also was associated with a reproducible positive change (Delta) in short-circuit current (Isc), which was abolished by inhibitors of chloride secretion. Capsaicin and hexamethonium significantly inhibited the DeltaIsc but not the release of 5-HT. The DeltaIsc was inhibited by TTX but not by atropine. It was also inhibited by the 5-HT(3,4) receptor antagonist tropisetron (10 microM) and the 5-HT(4,3) receptor antagonist SDZ-205-557 (10 microM) but not by preferential antagonists of 5-HT(1P), 5-HT(2A), or 5-HT3 receptors. These results suggest that mucosal stroking induces release of mucosal 5-HT, which activates a 5-HT4 receptor on enteric sensory neurons, evoking a neuronal reflex that stimulates chloride secretion.

Paradigm shifts in the treatment of abdominal aortic aneurysm: Trends in 721 patients between 1996 and 2008

OBJECTIVE This study evaluated longitudinal trends in abdominal aortic aneurysm (AAA) management after later-generation endografts became available. METHODS We retrospectively analyzed non-suprarenal AAA repairs between January 1, 1996, and December 31, 2008, performed at a single institution. Patients were stratified by endovascular AAA repair (EVAR) or open repair and the presence or absence of rupture. Thirty-day mortality rates were compared with the Fisher exact test. RESULTS During a 13-year period, 721 patients underwent AAA repair, comprising 410 (56.9%) with EVAR and 311 (43.1%) with open repair. A bimodal distribution of EVAR usage was observed, with initial escalation in the 1990s to 70%. A nadir of EVAR occurred in the early 2000s (40%), correlating with more conservative EVAR use after the limitations of first-generation endografts were understood. Between 2005 and 2008, average EVAR use increased to 84%. The overall 30-day mortality rate for the entire cohort, including ruptured AAA, was 3.8%: 2.0% (8 of 410) for EVAR and 6.1% (19 of 311) for open repair (P < .05). Ruptured AAA had a mortality rate of 0% (0 of 8) for EVAR vs 31% (9 of 29) for open (P = .16). Non-ruptured AAA mortality was 2.0% (8 of 402) for EVAR vs 3.6% (10 of 282) for open (P = .23). EVAR and open repair both had reductions in mortality in the latter half of the series, combining to provide a significant decrease in overall mortality to 1.8% for patients treated from 2003 to 2008 compared with 4.9% for 1996 to 2002 (P < .05). Open AAA repair became more complex during the study period. The average rate for juxtarenal open AAA repair was 17.7% (range, 6.5%-34.6%) between 1996 and 2002 compared with 55.6% (range, 29.6%-100%) between 2003 and 2008 (P < .05). CONCLUSIONS AAA treatment has undergone a profound and sustained paradigm shift, now averaging 84% of repairs performed with EVAR between 2005 and 2008. Overall mortality from AAA repair, including ruptures, was reduced 64% (from 4.9% to 1.8%) during the 13-year study period. Although EVAR and open repair both had improved mortality in the latter half of the series, the primary driver in reduced mortality for AAA repair has been the shift to EVAR.

Endovascular debranching of the aortic arch during thoracic endograft repair

BACKGROUND Treatment of complex thoracic aortic pathology increasingly requires coverage of one or more aortic arch vessels. Endovascular debranching with a chimney technique can reduce or eliminate the need for surgical bypass. In this study, we evaluate our initial experience with planned endovascular debranching of the aortic arch. METHODS During a 13-month period, nine patients were treated with endovascular debranching during thoracic endograft placement. Balloon expandable (n = 7) or self-expanding stents (n = 2) were deployed (innominate, n = 2; left common carotid, n = 2; left subclavian, n = 5) along with either TAG (W. L. Gore, Flagstaff, Ariz; n = 8) or Talent (Medtronic, Minneapolis, Minn; n = 1) endografts. Four patients required six surgical bypasses to additional arch vessels (right to left common carotid artery, n = 2; left common carotid to subclavian artery, n = 4). RESULTS Indications for thoracic endograft placement were aortic transection (n = 4), aortic aneurysm (n = 2), aortotracheal fistula (n = 1), contained aortic aneurysm rupture (n = 1), and acute aortic dissection (n = 1). Endografts were deployed into zones 0 (n = 2), 1 (n = 2), and 2 (n = 5). Technical success of endovascular debranching was attained in eight of nine patients, with maintenance of branch perfusion and absence of endoleak. Perioperative morbidity included one myocardial infarction and one stroke that resulted in the patients death. During subsequent follow-up (range, 2-25 months), there were no instances of endoleak secondary to chimney stents. All debranched vessels maintained primary patency. CONCLUSION Endovascular debranching permits planned extension of the thoracic endograft over arch vessels while further minimizing the need for open reconstruction. Short-term results indicate technical feasibility of this approach. Long-term outcomes remain undefined.

Central aortic wire confirmation for emergent endovascular procedures: As fast as surgeon-performed ultrasound.

BACKGROUND Uncontrolled hemorrhage is the leading cause of preventable death after trauma. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an evolving technique for controlling noncompressible torso hemorrhage. A challenge limiting REBOA use is the dependence on fluoroscopy for confirmation of intra-aortic positioning of a guide wire, a necessary component for safe and accurate balloon deployment. The current study evaluates using surgeon-performed sonography alone, without fluoroscopy, in identifying the aorta and the presence of an intra-aortic guide wire. We postulate that with the use of the subxiphoid Focused Abdominal Sonography for Trauma (FAST) view, both the aorta and an intra-aortic guide wire can be reliably identified. METHODS One hundred angiography patients underwent femoral arterial cannulation and guide wire advancement to the supraceliac aorta. From the subxiphoid FAST view, the aorta was identified in both sagittal and transverse planes. Intra-aortic wire identification was subsequently recorded. The rate of preferential central aortic wire positioning from unaided guide wire advancement was also observed. RESULTS The mean patient age and body mass index were 61.8 years and 27.0 kg/m2, respectively. Eighty-eight percent of the studies were performed using portable point-of-care ultrasound machines. Identification of the aorta via the subxiphoid FAST was successful in 97 (97%) of 100 patients in the sagittal and 98 (98%) of 100 patients in the transverse orientation. Among visualized aortas, an intra-aortic wire was identifiable in 94 (97%) of 97 patients in the sagittal and 91 (93%) of 98 patients in the transverse orientation. Unaided wire advancement achieved preferential central aortic positioning in 97 (97%) of 100 patients. Fluoroscopy-free ultrasound identification of an advancing intra-aortic guide wire was successful in 56 (98%) of 57 patients. CONCLUSION The subxiphoid FAST view can reliably identify a central aortic guide wire in both transverse and sagittal orientations. Unaided guide wire advancement has a high likelihood of both preferential central aortic positioning and subsequent ultrasound identification. These findings eliminate the need for routine fluoroscopy for this important initial maneuver during emergency endovascular procedures. LEVEL OF EVIDENCE Diagnostic study, level V.