Need for Limb Revascularization in Patients with Acute Aortic Dissection is Associated with Mesenteric Ischemia.

BACKGROUND: Acute aortic dissection (AAD) can cause limb ischemia due to branch vessel occlusion. A minority of patients have persistent ischemia after central aortic repair and require peripheral arterial revascularization. We investigated whether the need for limb revascularization is associated with adverse outcomes. METHODS: We reviewed our cases of AAD from 2000 to 2014 and identified patients with malperfusion syndromes (coronary, cerebral, spinal, visceral, renal, or peripheral ischemia). Patients with DeBakey I/II (Stanford type A) dissection had urgent open repair of the ascending aorta. Patients with DeBakey III (Stanford type B) dissection were initiated on anti-impulse medical therapy and had either open aortic repair or thoracic endovascular aortic repair for malperfusion syndromes. Patients with persistent lower limb ischemia after aortic repair usually had either extra-anatomic bypass grafting or iliac stenting. Some DeBakey III patients had peripheral revascularization without central aortic repair. We performed univariate and multivariate analysis to determine the effects of need for limb revascularization and clinical outcomes. RESULTS: We treated 1,015 AAD patients (501 [49.4%] DeBakey I/II and 514 [50.6%] DeBakey III) with a mean age of 59.7 ± 14.5 years (67.5% males). Aortic repair was performed in all DeBakey I/II patients and in 103 (20.0%) DeBakey III patients. Overall 30-day mortality was 11.3%. Lower limb ischemia was present in 104 (10.3%) patients and was more common in DeBakey I/II compared with DeBakey III dissections (65.4% vs. 34.6%; odds ratio [OR] 2.1, confidence interval [CI] 1.4-3.2; P = 0.001). Among the 40 patients who required limb revascularization, there was no difference in need for revascularization between DeBakey I/II and III patients. Patients requiring limb revascularization were more likely to have mesenteric ischemia compared with the rest of the cohort in both DeBakey I/II (P = 0.037) and DeBakey III dissections (P < 0.001) with worse 10-year survival (21.9 % vs. 59.2%, P < 0.001). When adjusted for other malperfusion syndromes, patients with limb revascularization had similar long-term survival compared to uncomplicated dissection patients (P = 0.960). CONCLUSIONS: Patients requiring lower limb revascularization after treatment for AAD are more likely to have mesenteric ischemia and worse survival. The need for limb revascularization is a marker for more extensive dissection and should prompt evaluation for visceral malperfusion.

Phenotypic responses to oil pollution in a poeciliid fish.

Pollution damages ecosystems around the globe and some forms of pollution, like oil pollution, can be either man-made or derived from natural sources. Despite the pervasiveness of oil pollution, certain organisms are able to colonise polluted or toxic environments, yet we only have a limited understanding of how they are affected by it. Here, we analysed phenotypic responses to oil pollution in guppies (Poecilia reticulata) living in oil-polluted habitats across southern Trinidad. We analysed body-shape and life-history traits for 352 individuals from 11 independent populations, six living in oil-polluted environments (including the naturally oil-polluted Pitch Lake), and five stemming from non-polluted habitats. Based on theory of, and previous studies on, responses to environmental stressors, we predicted guppies from oil-polluted waters to have larger heads and shallower bodies, to be smaller, to invest more into reproduction, and to produce more but smaller offspring compared to guppies from non-polluted habitats. Contrary to most of our predictions, we uncovered strong population-specific variation regardless of the presence of oil pollution. Moreover, guppies from oil-polluted habitats were characterised by increased body size; rounder, deeper bodies with increased head size; and increased offspring size, when compared to their counterparts from non-polluted sites. This suggests that guppies in oil-polluted environments are not only subject to the direct negative effects of oil pollution, but might gain some (indirect) benefits from other concomitant environmental factors, such as reduced predation and reduced parasite load. Our results extend our knowledge of organismal responses to oil pollution and highlight the importance of anthropogenic pollution as a source of environmental variation. They also emphasise the understudied ecological heterogeneity of extreme environments.

Risk of Mortality After Resolution of Spinal Malperfusion in Acute Dissection.

BACKGROUND: Spinal cord ischemia (SCI) may develop in patients presenting with acute aortic dissection. We sought to determine how SCI and its recovery affect outcomes. METHODS: We reviewed patients with SCI in acute type A aortic dissection (ATAAD) and acute type B aortic dissection (ATBAD) from September 1999 to May 2014. SCI was defined as paraplegia or paraparesis present on admission. Monoparesis/plegia, paraesthesia, or numbness was defined as ischemic neuropathy. All ATBAD patients were managed with antiimpulse therapy, with selective intervention for rupture, rapid aortic expansion, malperfusion, or intractable pain. ATAAD patients were managed with urgent proximal aortic replacement. RESULTS: Neurologic symptoms were present in 178 (18.2%) of 978 acute dissections (482 ATAAD and 496 ATBAD). Of these 178 patients, SCI presented in 52 patients (29.2%; 80.1% male; mean age, 57 years). On admission paraplegia was present in 24 (46.2%), paraparesis in 10 (19.2%), paresthesia/numbness in 27 (51.9%), and leg ischemia in 25 (48.1%). Aortic operations were performed in 27 SCI patients (51.9%). Symptom resolution was seen in 30 (57.7%). The 30-day mortality was 19.2% and was significantly less in those with resolution of SCI (6.7% vs 36.4%, p = 0.012). When surgical intervention was required in ATBAD with SCI, mortality was 50% (p = 0.039). SCI and symptom resolution significantly affected overall survival. SCI is associated with significantly increased risk of overall mortality (hazard ratio, 2.9; p < 0.001), and SCI resolution completely offsets this risk (hazard ratio, 0.28; p = 0.003). These effects were consistent between ATAAD and ATBAD (p = 0.554). CONCLUSIONS: SCI in acute aortic dissection portends a poor prognosis. However, reversal of deficits is associated with a long-term survival outcome comparable to patients unaffected with SCI.