Advancing remote sensing and machine learning-driven frameworks for groundwater withdrawal estimation in Arizona: Linking land subsidence to groundwater withdrawals.

Groundwater plays a crucial role in sustaining global food security but is being over-exploited in many basins of the world. Despite its importance and finite availability, local-scale monitoring of groundwater withdrawals required for sustainable water management practices is not carried out in most countries, including the United States. In this study, we combine publicly available datasets into a machine learning framework for estimating groundwater withdrawals over the state of Arizona. Here we include evapotranspiration, precipitation, crop coefficients, land use, annual discharge, well density, and watershed stress metrics for our predictions. We employ random forests to predict groundwater withdrawals from 2002 to 2020 at a 2 km spatial resolution using in situ groundwater withdrawal data available for Arizona Active Management Areas (AMA) and Irrigation Non-Expansion Areas (INA) from 2002 to 2009 for training and 2010-2020 for validating the model respectively. The results show high training ( R 2 ≈ 0.9 ) and good testing ( R 2 ≈ 0.7 ) scores with normalized mean absolute error (NMAE) ≈ 0.62 and normalized root mean square error (NRMSE) ≈ 2.34 for the AMA/INA region. Using this method, we spatially extrapolate the existing groundwater withdrawal estimates to the entire state and observe the co-occurrence of both groundwater withdrawals and land subsidence in South-Central and Southern Arizona. Our model predicts groundwater withdrawals in regions where production wells are present on agricultural lands and subsidence is observed from Interferometric Synthetic Aperture Radar (InSAR), but withdrawals are not monitored. By performing a comparative analysis over these regions using the predicted groundwater withdrawals and InSAR-based land subsidence estimates, we observe a varying degree of subsidence for similar volumes of withdrawals in different basins. The performance of our model on validation datasets and its favourable comparison with independent water use proxies such as InSAR demonstrate the effectiveness and extensibility of our combined remote sensing and machine learning-based approach.

Management of Aortic Pseudoaneurysms: Evolving Concepts and Controversies.

BACKGROUND: Techniques to repair aortic pseudoaneurysms have been rapidly evolving. We present our results following open and endovascular repair of aortic pseudoaneurysms from 2009 to 2013. METHODS: A total of nine patients underwent pseudoaneurysm repair from April 2009 to February 2013. Of them, five underwent open repair and four underwent endovascular repair. The median age was 58 years (range, 40-72 years) and two (22%) were females. Preoperative, operative, and postoperative data are presented along with operative modality. RESULTS: Two patients died during the period of study. Patient 1 died from massive hemorrhage at the site of prior stenting. Patient 7 died from postoperative cardiac arrest and respiratory failure. A single patient required hemorrhage-related reexploration. None of the patients experienced stroke or acute renal failure following repair. Median hospital and intensive care unit length of stays were 7.1 (range, 1-20) and 2.0 (range, 1-5), respectively. CONCLUSIONS: Pseudoaneurysm repair can be effectively achieved through open or percutaneous repair but only after careful consideration of anatomical constraints, as well as patient comorbidities.

Role of Moderate Hypothermia and Antegrade Cerebral Perfusion during Repair of Type A Aortic Dissection.

The goal of this study was to compare early postoperative outcomes and actuarial survival between patients who underwent repair of acute type A aortic dissection with deep or moderate hypothermia. A total of 132 consecutive patients from a single academic medical center underwent repair of acute type A aortic dissection between January 2000 and June 2014. Of those, 105 patients were repaired under deep hypothermia (< 24 C°), while 27 patients were repaired under moderate hypothermia (≥24 C°). Median ages were 62 years (range: 27-86) and 59 years (range: 35-83) for patients repaired under deep hypothermia compared with patients repaired under moderate hypothermia, respectively ( p = 0.451). Major morbidity, operative mortality, and 10-year actuarial survival were compared between groups. Operative mortality was 17.1 and 7.4% in the deep and moderate hypothermia groups, respectively ( p = 0.208). Incidence of permanent stroke was 12.4% in the deep hypothermic circulatory arrest group and 0% in the moderate hypothermia group ( p = 0.054). Actuarial 5- and 10-year survival demonstrated a trend for lower long-term mortality with moderate hypothermia compared with deep hypothermia (69% 5-year and 54% 10-year for deep hypothermia vs. 79% 5-year and 10-year for moderate hypothermia, log-rank p = 0.161). Moderate hypothermia is a safe and efficient alternative to deep hypothermia and may have protective benefits. Stroke rate was lower with moderate hypothermia.

Bovine arch anatomy influences recoarctation rates in the era of the extended end-to-end anastomosis.

OBJECTIVES: Arch branching has never been shown to influence recoarctation after extended end-to-end anastomosis via thoracotomy, yet in each study bovine arch identification is grossly underreported. This study aims to (1) assess chart review reliability in bovine arch identification; (2) determine recoarctation risk with a bovine arch; and (3) explore an anatomic explanation for recurrent arch obstruction based on arch anatomy. PATIENTS: A total of 49 consecutive patients underwent thoracotomy with extended end-to-end aortic coarctation repair at a single institution (2007-2012). METHODS: Echocardiograms from these patients were reviewed for arch anatomy and compared with the echocardiographic reports. Recurrent arch obstruction was defined as an echocardiographic gradient across the repair of 20 mm Hg or greater. For cases with angiographic images (n = 17), a scaled clamping distance between the left subclavian artery and the maximal proximal clamp location on orthogonal projections was then calculated across arch anatomies. RESULTS: Chart review identified 6.1% (3/49) of patients with a bovine arch compared with 28.6% (14/49) on targeted image review. A total of 28.6% (4/14) of patients with a bovine arch had a follow-up gradient of 20 mm Hg or greater. Only 5.7% (2/35) of patients with normal arch branching had a follow-up gradient of 20 mm Hg or greater. The mean clamping index was significantly diminished in patients with bovine arch anatomy. CONCLUSIONS: Arch anatomy often goes undocumented on preoperative imaging, yet children undergoing extended end-to-end repair with bovine arch anatomy are at a significantly increased risk of recoarctation. This may be due to a reduced clampable distance to facilitate repair. These results should be considered in the preoperative assessment, parental counseling, and surgical approach for children with discrete aortic coarctation.

Effects of Gender on Outcomes and Survival Following Repair of Acute Type A Aortic Dissection.

Previous studies have demonstrated gender-related differences in early and late outcomes following type A dissection diagnosis. However, it is widely unknown whether gender affects early clinical outcomes and survival after repair of type A aortic dissection. The goal of this study was to compare the early and late clinical outcomes in women versus men after repair of acute type A aortic dissections. Between January 2000 and October 2010 a total of 251 patients from four academic medical centers underwent repair of acute type A aortic dissection. Of those, 79 were women and 172 were men with median ages of 67 (range, 20-87 years) and 58 years (range, 19-83 years), respectively (p < 0.001). Major morbidity, operative mortality, and 10-year actuarial survival were compared between the groups. Operative mortality was not significantly influenced by gender (19% for women vs. 17% for men, p = 0.695). There were similar rates of hemodynamic instability (12% for women vs. 13% men, p = 0.783) between the two groups. Actuarial 10-year survival rates were 58% for women versus 73% for men (p = 0.284). Gender does not significantly impact early clinical outcomes and actuarial survival following repair of acute type A aortic dissection.

A minimally invasive, algorithm-based approach for anomalous aortic origin of a coronary artery.

OBJECTIVE: Operative repair for anomalous aortic origin of a coronary artery (AAOCA) has been described using various innovative techniques. Common to each series is the use of a full sternotomy. As demand for minimally invasive approaches to adult cardiac surgery has increased, the upper hemisternotomy has emerged as a safe and effective technique for aortic valve and root replacement. This report reviews our results and describes the application of an upper hemisternotomy to an algorithm-based surgical approach for AAOCA. METHODS: From January 2012 to March 2013, the aortic root was approached via a 7-cm skin incision and upper hemisternotomy for all patients undergoing repair of an AAOCA. The type of repair performed was in accordance with a predefined surgical algorithm. The anomalous vessel had a slit-like ostium and followed a supracommissural intramural course in three patients with symptomatic anomalous right coronary artery. These patients underwent coronary unroofing. In contrast, a patient with an anomalous left coronary artery presented without an intramural segment and underwent vessel translocation and reimplantation. RESULTS: All patients underwent AAOCA repair according to our surgical algorithm and via an upper hemisternotomy. The median length of stay was 4 days. All patients had resolution of symptoms, and there were no reported complications at a median follow-up of 16.5 months. CONCLUSIONS: This series describes a minimally invasive approach to AAOCA repair. When used in conjunction with a defined surgical algorithm, this technique enables a safe and effective repair in all forms of AAOCA without concomitant coronary artery disease.

Improved clinical outcomes and survival following repair of acute type A aortic dissection in the current era.

OBJECTIVES: The goal of this study was to compare early postoperative outcomes and actuarial-free survival between patients who underwent repair of acute type A aortic dissection during 2000-2005 and 2006-2010. METHODS: A total of 251 patients from four academic medical centres underwent repair of acute type A aortic dissection between January 2000 and October 2010. Of those, 111 patients underwent repair during 2000-2005, whereas 140 patients underwent repair during 2006-2010. Median ages were 62 years (range 20-83) and 58 years (range 30-80) for patients repaired from 2000-2005 compared with those repaired during 2006-2010, respectively (P = 0.180). Major morbidity, operative mortality and 5-year actuarial survival were compared between groups. Multivariate logistic regression was used to determine predictors of operative mortality. RESULTS: Operative mortality was strongly influenced by surgical era (24% for 2000-2005 vs 12% for 2006-2010, P = 0.013). In multivariable logistic regression analysis, haemodynamic instability [odds ratio (OR) = 17.8, 95% confidence intervals (CIs) = 0.05-0.35, P <0.001], cardiopulmonary bypass time >200 min (OR = 9.5, 95% CI = 0.14-0.64, P = 0.002) and earlier date of surgery (OR = 5.8, 95% CI = 1.18-5.14, P = 0.016) emerged as independent predictors of operative mortality. Actuarial 5-year survival was worse for earlier compared with later date of surgery (64% for 2000-2005 vs 77% for 2006-2010, log-rank P <0.001). CONCLUSIONS: Surgical era significantly impacts early outcomes and actuarial survival following repair of acute type A aortic dissection.

Effects of Hemodynamic Instability on Early Outcomes and Late Survival Following Repair of Acute Type A Aortic Dissection.

BACKGROUND: The goal of this study was to compare operative mortality and actuarial survival between patients presenting with and without hemodynamic instability who underwent repair of acute Type A aortic dissection. Previous studies have demonstrated that hemodynamic instability is related to differences in early and late outcomes following acute Type A dissection occurrence. However, it is unknown whether hemodynamic instability at the initial presentation affects early clinical outcomes and survival after repair of Type A aortic dissection. METHODS: A total of 251 patients from four academic medical centers underwent repair of acute Type A aortic dissection between January 2000 and October 2010. Of those, 30 presented with hemodynamic instability while 221 patients did not. Median ages were 63 years (range 38-82) and 60 years (range 19-87) for patients presenting with hemodynamic instability compared to patients without hemodynamic instability, respectively (P = 0.595). Major morbidity, operative mortality, and 10-year actuarial survival were compared between groups. RESULTS: Operative mortality was profoundly influenced by hemodynamic instability (patients with hemodynamic instability 47% versus 14% for patients without hemodynamic instability, P < 0.001). Actuarial 10-year survival rates for patients with hemodynamic instability were 44% versus 63% for patients without hemodynamic instability (P = 0.007). CONCLUSIONS: Hemodynamic instability has a profoundly negative impact on early outcomes and operative mortality in patients with acute Type A aortic dissection. However, late survival is comparable between hemodynamically unstable and non-hemodynamically unstable patients.

Renal artery implantation angles in thoracoabdominal aneurysms and their implications in the era of branched endografts.

PURPOSE: To determine the renal artery to aorta relationship in the setting of thoracoabdominal aortic aneurysm (TAAA) in order to help strategize preoperative stent-graft planning, device design, and deployment technicalities. METHODS: The preoperative computed tomography (CT) studies of 147 patients who underwent TAAA repair between 2005 and 2008 were retrospectively reviewed. The Crawford classification of the TAAA, the renal artery implantation angle (RAIA), and the maximal aortic diameter were determined using 3-dimensional imaging analysis (centerline of flow). RAIAs were determined to be positive or negative as a function of their relative position above or below the plane perpendicular to the centerline of flow at the level of the renal ostia. RAIAs and maximum aortic diameters were compared between types II/III TAAA (n = 72) and type IV TAAA (n = 75), stratified by side, and examined for correlation. RESULTS: Maximal aortic diameter was not significantly different between the 2 groups: 67.5+/-13.4 mm for type II/III versus 65.3+/-12.5 mm for type IV (p = 0.3). There was no correlation between the maximal aortic diameter and the RAIAs. RAIAs in type II/III TAAAs were commonly orthogonal to the aortic centerline (mean -5.7 degrees +/-19.1 degrees on the right and -2.8 degrees +/-22.4 degrees on the left, respectively), while type IV TAAAs had downward pointing renal arteries (mean -24.1 degrees +/-18.4 degrees and -20.4 degrees +/-18.8 degrees for the right and left, respectively). There was a significant difference between the two groups regarding RAIAs on both sides (p<0.00001). CONCLUSION: The primary location of longitudinal aortic growth will drive the RAIA in a cranial or caudal direction. When the disease process is largely located below the renal ostia, infrarenal aortic lengthening drives the renal ostia cranially, forcing the implantation angle of the renal ostia to be caudally directed. The opposite occurs in type II or III TAAAs, where the bulk of disease is above the renal arteries, driving the ostia down to create RAIAs that are nearly orthogonal to the centerline of flow. Utilization of this data could result in endovascular grafts designed with branches replacing fenestrations for renal artery perfusion.