The aortic arch and ascending aorta: are they within the endovascular realm?

Aneurysms involving the ascending aorta and arch have been historically treated with open surgical techniques requiring cardiopulmonary bypass and, in cases involving the aortic arch, utilizing deep hypothermic circulatory arrest. The reported rates of mortality range from 0% to 16.5% for surgery addressing ascending aorta and arch pathology, and stroke rates of 2% to 18%. These statistics highlight the invasiveness of these procedures. Continued development and evolution of endovascular stent-grafts has allowed for the application of endovascular interventions in the proximal descending thoracic aorta and visceral aortic segments. Based on early experiences, attention has been focused on the ascending aorta and aortic arch, where unique challenges exist and have been addressed by both extra-anatomic bypass and novel methods incorporating branched and fenestrated devices. Device evolution, coupled with increased experience by the aortic interventionalist, has resulted in successful cases of endovascular management of every section of the aorta, including aortic valve replacement. However, these experiences have also been accompanied by significant complications. In this light, new endovascular endeavors must be considered in the context of conventional treatment options, hybrid procedures, and novel branched devices. Patient factors, such as specific anatomic issues, comorbid diseases, and functional levels must play an important role in the determination of therapeutic options. Ultimately, a clinician who understands the disease and is familiar with all treatment options (interventional, medical, and open surgical) will be best suited to provide care for the aortic patient. Finally, as with any assessment of interventional strategies, rigorous follow-up and serial imaging are essential.

A novel organ culture method to study intimal hyperplasia at the site of a coronary artery bypass anastomosis.

BACKGROUND: Intimal hyperplasia or restenosis at the site of a coronary artery bypass anastomosis contributes to early graft failure, and growth factor release in response to construction of the anastomotic site strongly influences this process. Due to the difficulties in studying restenosis after coronary artery bypass graft surgery, we have tested whether an organ culture model we have developed can simulate the early events associated with intimal hyperplasia. METHODS: End-to-side anastomosis of porcine radial artery to porcine coronary artery were constructed. The vessels were trimmed and incubated under standard tissue culture conditions for 14 days. Appropriate controls were treated similarly. The vessels were frozen, cryosectioned, and immunostained for the expression of the proliferation marker proliferating cell nuclear antigen (PCNA). A proliferative index (PCNA positive nuclei/total nuclei) was calculated for comparative purposes. RESULTS: Limited PCNA staining was observed in noncultured vessel segments (0.046+/-0.045). A slight increase in this index was observed in vessels that had been placed into culture without manipulation (0.230+/-0.141) and in vessels subjected to an arteriotomy (0.462+/-0.249). However, the most significant increase was obtained after construction of an anastomosis (4.98+/-6.66). No change in total cell number was evident over the course of the experiment or in relation to the treatment. CONCLUSIONS: Culture conditions and incision slightly stimulate cell proliferation in porcine coronary artery segments when compared with basal conditions of a native artery. In contrast, construction of an anastomosis increases proliferation 108-fold. Therefore, surgical manipulation of arterial conduits during construction of an anastomotic site is the primary trigger for intimal hyperplasia, independent of dissection and incision of the vessel. Furthermore, these data indicate the organ culture model we have developed will be useful for examining the cellular and molecular mechanisms that mediate intimal hyperplasia at the site of a coronary artery bypass graft anastomosis.

Safety and efficacy of fast track in patients undergoing coronary artery bypass surgery.

BACKGROUND: The incidence of coronary artery bypass surgery has been increasing annually with increasing pressure on the health care system. Fast track has been proposed as a means to increase efficiency and volume, without an increase in hospital resources. To date this approach has not been critically assessed in Canada. METHODS: We examined 617 consecutive patients undergoing isolated CABG surgery. The patients were divided into (1) fast track (FT) recovery (n = 219), without admission to an ICU, and (2) non-fast track (NFT) recovery (n = 398) with direct admission to the ICU. There were no differences in age, gender, timing of surgery, left main stenosis, preoperative myocardial infarction, renal failure, diabetes, peripheral vascular disease, or in the incidence of chronic obstructive pulmonary disease between the two groups. The NFT group had a higher proportion of patients with NYHA Class III/IV symptoms preoperatively (65.7% vs. 57.3%, p = 0.048), in patients with an ejection fraction < 40% (42.5% vs. 30.6%, p = 0.004), or in the number of individuals with an IABP inserted before surgery (13 vs. 1, p < 0.001). RESULTS: In the FT group the average period of aortic occlusion (40.7 +/- 15.2 min vs. 71.8 +/- 26.5 min, p < 0.001) and perfusion time (67.8 +/- 24.5 min vs. 117.5 +/- 40.2 min, p < 0.001) were significantly less than in the NFT group. The number of grafts per patient was 3.3 +/- 1.0 vs. 3.2 +/- 1.0, respectively (p = 0.38). Operative mortality was 0.9% in the FT group and 1.3% in the NFT group (p = 1.0). Significant differences were seen in the proportion of patients that suffered from postoperative ventilatory failure (3.2% in FT vs. 12.1% in NFT, p < 0.001), and the proportion of patients that suffered any postoperative complication was significantly higher in the NFT group (21.4%) than in the FT group (9.1%, p < 0.001). The differences in postoperative complications resulted in a shorter length of stay (LOS) in FT patients (5.6 +/- 4.1 days vs. 9.7 +/- 9.4 days NFT, p < 0.001). Only 4.1% of patients that entered the FT group failed and required admission to the ICU. Multivariate stepwise logistic regression analysis identified non-fast track recovery as an independent predictor of morbidity in CABG surgery patients. CONCLUSIONS: The data indicate it is possible to perform isolated CABG surgery, in a large proportion of the population, without the need for admission to an ICU for postoperative care.