The risk of patient-prosthesis mismatch drives most surgeons to select the largest bioprosthesis possible during aortic valve replacement, but interactions between the native aortic annulus and valve ...prosthesis remain poorly defined. We examined the hemodynamic and functional consequences of oversizing contemporary bioprostheses in an in vitro model.
Three sizes each (21, 23, and 25 mm) of 5 aortic bioprostheses (Magna, Edwards Lifesciences, Irvine, CA; Trifecta and Epic, St. Jude, St. Paul, MN; and Mosaic and Hancock II, Medtronic, Minneapolis, MN) were tested on a mock annulus in a pulsatile aortic simulator. After the annulus was sized to match each valve, the annulus was decreased by 3 mm and then by 6 mm to simulate oversizing. We measured the effective orifice area and the mean pressure gradient. Changes in prosthetic leaflet behavior and geometric orifice area were assessed with slow-motion video. Statistical analysis used mixed-effects models for repeated-measures data, allowing comparison within and between groups.
For each valve model and size, oversizing resulted in decreased effective orifice areas and geometric orifice areas and increased pressure gradients. This was more pronounced with smaller valve sizes and higher flow rates but varied between valve types. Slow-motion imaging revealed this change in geometric orifice area was a result of an inward shift of the valve leaflet hinge point.
Bioprosthetic oversizing impairs hemodynamic performance of aortic valve bioprostheses. The magnitude of this effect varies by valve model and size. Clinically, these data suggest that during aortic valve replacement, placing a valve whose internal orifice closely matches the aortic annulus will provide the optimal hemodynamic performance.
Abstract Objective To evaluate outcomes after mitral valve repair. Methods Between May 1999 and June 2015, 446 patients underwent mitral valve repair. Isolated mitral valve annuloplasty was excluded. ...A total of 398 (89%) had degenerative valve disease. Mean follow-up was 5.5 ± 3.8 years. Postoperative echocardiograms were obtained in 334 patients (75%) at a mean of 24.3 ± 13.7 months. Results Survival was 97%, 96%, 95%, and 94% at 1, 3, 5, and 10 years. Risk factor analysis showed age >60 years and nondegenerative etiology predict death (hazard ratio, 2.91; 95% confidence interval, 1.06-8.02, P = .038; and hazard ratio, 1.87; 95% confidence interval, 1.16-3.02, P = .010, respectively). Considering competing risks due to mortality, the cumulative incidence of reoperation was 2.8%, 4.2%, 5.1%, and 9.6% at 1, 3, 5, and 10 years. Competing risk proportional hazard survival regression identified nondegenerative etiology and previous cardiac surgery as predictors of reoperation, and posterior repair was protective (all P < .05). Cumulative incidence of progression of mitral regurgitation (2 or more grades) with mortality as a competing risk was 4.7%, 10.5%, 21.0%, and 35.8% at 1, 3, 5, and 10 years. Patients with previous sternotomy, repair or coronary artery bypass grafting, and concurrent tricuspid valve procedure or isolated anterior leaflet repair were more likely to develop progression of mitral regurgitation (all P < .05), and posterior leaflet repair was protective ( P = .038). On multivariate analysis diabetes, previous coronary artery bypass grafting and concurrent tricuspid valve intervention predicted MR progression. Conclusions Mitral valve repair has excellent outcomes. Our results demonstrate failures appear to occur less in those who undergo posterior leaflet repair.
The use of extracorporeal life support (ECLS) worldwide has increased exponentially since 2009. The patient requiring ECLS demands an investment of hospital resources, including personnel. Educating ...bedside nurses to manage ECLS circuits broadens the availability of trained providers.
Experienced cardiothoracic intensive care unit (CTICU) nurses underwent training to manage ECLS circuits, including volume assessment, treatment of arterial blood gas values, the physiology of ECLS, and recognition of common emergencies. In addition to lectures and a written examination, simulation using water circuits and an ICU model allowed assessment of skills and understanding of concepts. Performance assessments were completed regularly at the bedside, and skills revalidation occurred every 6 months. A sequential cohort of 40 patients was tracked over 1 year.
Despite doubling the census of ECLS patients in 1 year, management by specially trained CTICU nurses has positively affected patient care and outcomes. At a single institution, 40 patients had a median of 6 days (interquartile range, 2 to 226 days) of support in 2014, leading to 767 patient-days of support. Survival to hospital discharge increased to 45% in 2014. Most survivors were weaned from support. Neurologic injury was the most common cause of death, followed by failure to qualify for advanced therapies.
With on-going education and assessment, including crisis training, physiology, and cannulation strategies, CTICU nurses can safely operate ECLS circuits and can increase the availability of appropriately trained providers to accommodate the exponential increase in ECLS occurrences without negatively affecting outcomes and generally at a lower cost.
Background The late durability of endovascular aneurysm repair (EVAR) has been limited by progressive aortic degeneration believed to be mediated by matrix metalloproteases (MMP). The goal of this ...study was to evaluate the effect of a MMP inhibitor, doxycycline, on EVAR. Methods Patients undergoing EVAR were randomized to doxycycline (100 mg twice daily) or placebo for 6 months following the procedure. Clinical data, blood samples, and computed tomography (CT) scans were obtained preoperatively, postoperatively (blood only), and at 1- and 6-month follow-up. Forty-four subjects were analyzed based on intention-to-treat. Results Plasma MMP-9 decreased significantly below baseline in the doxycycline (N = 20) treated patients at 6 months (−16.4% ± 20.7%, P < .05) while there was a nonsignificant increase in the placebo (N = 24) group (128.1% ± 73.5%). This was primarily related to changes between 1 and 6 months. In patients with endoleaks at 6 months, plasma MMP-9 increased in 83% of the placebo treated patients, but in only 14% of the doxycycline treated group ( P < .03). Among endoleak-free patients with AneuRx or Excluder endografts, doxycycline treatment resulted in greater decreases in maximum aortic diameter than placebo treatment (−13.3% ± 3.3% vs −3.8% ± 3.0%, P < .05). Furthermore, doxycycline treatment significantly reduced the aortic neck dilatation at 6 months in Excluder treated patients. Conclusion There is evidence of persistent MMP release representing ongoing aortic degradation after endografting which can be inhibited by doxycycline therapy. In analyses based on the endograft used, treatment with doxycycline also demonstrated evidence of increased aortic dimensional stability, a surrogate marker for long-term success of EVAR. Although encouraging, these results require confirmation in larger patient populations. Doxycycline should undergo more thorough evaluation as a potential adjuvant treatment to improve the results of EVAR, particularly in certain subgroups.
Objective The development of abdominal aortic aneurysms (AAA) is presumed to result from multiple genetic and environmental factors, with exposure to tobacco smoke the single largest known factor ...predisposing to aneurysm growth. We have attempted to adapt the elastase-perfused animal model to determine whether tobacco exposure can lower the threshold of aortic injury necessary for AAA development. Methods Adult C57BL/6 mice underwent transient perfusion of the infrarenal aorta with an active solution of elastase: high-dose (HDE, 0.19 U/mL, n = 9), standard-dose (SDE, 0.16 U/mL, n = 21) or low-dose (LDE, 0.07 U/mL, n = 24). Control animals (n = 24) were treated with heat inactivated elastase (HIE). Twenty LDE perfused mice were exposed to cigarette smoke (LDE-S) beginning 2 weeks before perfusion and continuing until aortic harvest. Aortic diameter (AD) was measured preperfusion, postperfusion, and at harvest on day 14. AAA was defined as %ΔAD ≥100% between preperfusion and harvest. Aortas from each group (except HDE) were analyzed for matrix metalloproteinase-9 (MMP-9) and MMP-12 expression by real-time polymerase chain reaction normalized to glyceraldehyde-3-phosphate dehydrogenase. Results All SDE mice developed large AAA by %ΔAD (189.3% ± 16.9%, mean ± standard error of the mean), but control mice had only a small dilatation (69.7% ± 3.7%, P < .01). Higher doses of elastase did not produce larger aneurysms in HDE mice. In contrast, only 63% of LDE mice showed aneurysmal dilatation, and these were significantly smaller (104.3% ± 4.2%, P < .01). When exposed to cigarette smoke, LDE animals developed significantly larger aneurysms (%ΔAD, 134.5% ± 7.9%, P = .0021). There was no difference in normalized aortic MMP-9 and MMP-12 expression between elastase doses or between smoke-exposed and unexposed animals. Histologic analysis revealed that smoking increased the extent of aortic elastin degradation when compared with LDE-S animals. Conclusion Aneurysm development in the elastase model is dependent on the quantity of active elastase infused. Exposure of animals to tobacco smoke after a relatively minor aortic elastase injury produces increases in elastin degradation and aneurysm size without affecting MMP-9 or MMP-12 expression. To our knowledge, this is the first demonstration in an animal model that smoking can act as a synergistic factor in AAA development. Further understanding of the relationship between smoking and AAA in this model may help unveil the pathophysiologic pathways involved between cigarette smoke and AAAs.
PDF
