Publications by authors named "Annalise M Panthofer"

6 Publications

  • Page 1 of 1

Post-Kidney Transplant Serum Magnesium Exhibits a U-Shaped Association with Subsequent Mortality: An Observational Cohort Study.

Transpl Int 2021 Jun 3. Epub 2021 Jun 3.

Division of Nephrology, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America.

Background: Hypomagnesemia is common in kidney transplant recipients (KTRs). We sought to explore the relationship between Mg and outcomes in KTRs, which may be associated with mortality and thus, may be a potential intervention target to improve outcomes.

Methods: We followed KTRs performed between 01/2000 and 6/2016 at a large US transplant center from 6 months post-transplant to graft failure, death, or loss to follow-up. Using Mg as a time-dependent variable, associations between Mg and outcomes any time after 6-months post-transplant were evaluated.

Results: 3,680 KTRs with 50,413 Mg measurements met inclusion criteria. 657 deaths occurred over a median follow-up of 5.1 years. Compared to Mg of 1.5-1.8 mg/dL, both lower (HR 1.17, 95% Confidence interval (CI): 1.07-1.28) and higher (HR 1.16, 95% CI: 1.09-1.23) Mg levels were associated with greater risk of mortality. Similar U-shaped associations were observed for Mg and cardiovascular disease-related mortality (HR for Mg ≤1.5 mg/dL: 1.31; CI: 1.03-1.68) and infection-related mortality (HR for Mg ≤1.5 mg/dL: 1.28; CI: 1.09-1.51), although relationships for Mg >1.8 mg/dL were not statistically significant.

Conclusions: Mg exhibits a U-shaped association with mortality in KTRs, with levels between 1.5-1.8 mg/dL associated with the lowest risk.
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June 2021

Anatomic eligibility for endovascular aneurysm repair preserved over 2 years of surveillance.

J Vasc Surg 2021 May 4. Epub 2021 May 4.

School of Medicine and Public Health, Division of Vascular Surgery, University of Wisconsin, Madison, Wisc.

Objective: Endovascular aneurysm repair (EVAR) is a widely used option for patients with suitable vascular anatomy who have a large infrarenal abdominal aortic aneurysm (AAA). Patients with small AAAs are managed with careful surveillance and it is a common concern that their anatomy may change with AAA growth, and their option for EVAR may become limited. Device innovation has resulted in expanded ranges of anatomy that may be eligible for EVAR. This study sought to identify changes in anatomic eligibility for repair with contemporary endovascular devices in AAA patients, monitored by computed tomography scan over the course of 2 years.

Methods: Patients from the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TACT, NCT01756833) were included in this analysis. Females had baseline AAA maximum transverse diameter between 3.5 and 4.5 cm, and males had baseline maximum transverse diameter between 3.5 and 5.0 cm. Patients were included in this analysis if they completed pre-enrollment and 2-year follow-up computed tomography imaging. Pertinent anatomic measurements were performed on a postprocessing workstation in a centralized imaging core laboratory. EVAR candidacy was determined by measuring proximal aortic neck diameter, AAA length, and infrarenal neck angulation. Patients were considered to be eligible for EVAR if they qualified for at least one of the seven studied devices' instructions for use at baseline and at 2 years. A paired t test analysis was used to detect differences in aortic measurements over 2 years, and the McNemar test was used to compare eligibility over 2 years.

Results: We included 192 patients in this analysis-168 male and 24 female. Of these patients, 85% were eligible for EVAR at baseline and 85% after 2 years of follow-up (P = 1.00; 95% confidence interval -0.034 to 0.034). Of the 164 EVAR candidates at baseline, 160 (98%) remained eligible over 2 years of surveillance. Insufficient neck length was the most common reason for both ineligibility at baseline (18 of 28 patients) as well as loss of candidacy over 2 years (3 of 4 patients).

Conclusions: The majority of patients eligible for EVAR when entering a surveillance program for small AAA remain eligible after 2 years. Substantial changes in AAA neck anatomy resulting in loss of EVAR treatment options are infrequent. Patients with anatomic AAA progression beyond EVAR eligibility remain candidates for complex EVAR and open repair.
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May 2021

Evaluating Growth Patterns of Abdominal Aortic Aneurysm Diameter With Serial Computed Tomography Surveillance.

JAMA Surg 2021 Apr;156(4):363-370

Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison.

Importance: Small abdominal aortic aneurysms (AAAs) are common in the elderly population. Their growth rates and patterns, which drive clinical surveillance, are widely disputed.

Objective: To assess the growth patterns and rates of AAAs as documented on serial computed tomography (CT) scans.

Design, Setting, And Participants: Cohort study and secondary analysis of the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA3CT), a randomized, double-blind placebo-controlled clinical trial conducted from 2013 to 2018, with CT imaging every 6 months for 2 years. The trial was a multicenter, observational secondary analysis, not related to treatment hypotheses of data collected in the N-TA3CT. Participants included 254 patients with baseline AAA diameter between 3.5 and 5.0 cm.

Exposures: Patients received serial CT scan measurements, analyzed for maximum transverse diameter, at 6-month intervals.

Main Outcomes And Measures: The primary study outcome was AAA annual growth rate. Secondary analyses included characterizing AAA growth patterns, assessing likelihood of AAA diameter to exceed sex-specific intervention thresholds over 2 years.

Results: A total of 254 patients, 35 women with baseline AAA diameter 3.5 to 4.5 cm and 219 men with baseline diameter 3.5 to 5.0 cm, were included. Yearly growth rates of AAA diameters were a median of 0.17 cm/y (interquartile range [IQR], 0.16) and a mean (SD), 0.19 (0.14) cm/y. Ten percent of AAAs displayed minimal to no growth (<0.05 cm/y), 62% displayed low growth (0.05-0.25 cm/y), and 28% displayed high growth (>0.25 cm/y). Baseline AAA diameter accounted for 5.4% of variance of growth rate (P < .001; R2, 0.054). Most AAAs displayed linear growth (70%); large variations in interval growth rates occurred infrequently (3% staccato growth and 4% exponential growth); and some patients' growth patterns were not clearly classifiable (23% indeterminate). No patients with a maximum transverse diameter less than 4.25 cm exceeded sex-specific repair thresholds at 2 years (men, 0 of 92; 95% CI, 0.00-0.055; women, 0 of 25 ; 95% CI, 0.00-0.247). Twenty-six percent of patients with a maximum transverse diameter of at least 4.25 cm exceeded sex-specific repair thresholds at 2 years (n = 12 of 83 men with diameter ranging from 4.25 to <4.75 cm; 95% CI, 0.091-0.264; n = 21 of 44 men with diameter ranging from 4.75-5.0 cm; 95% CI, 0.362-0.669; n = 3 of 10 women with diameter ≥4.25 cm; 95% CI, 0.093-0.726).

Conclusions And Relevance: Most small AAAs showed linear growth; large intrapatient variations in interval growth rates were infrequently observed over 2 years. Linear growth modeling of AAAs in individual patients suggests smaller AAAs (<4.25 cm) can be followed up with a CT scan in at least 2 years with little chance of exceeding interventional thresholds.

Trial Registration: Identifier: NCT01756833.
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April 2021

CT-Derived Pretreatment Thoracic Sarcopenia Is Associated with Late Mortality after Thoracic Endovascular Aortic Repair.

Ann Vasc Surg 2020 Jul 6;66:171-178. Epub 2019 Nov 6.

Division of Vascular Surgery, University of Wisconsin School of Medicine & Public Health, Madison, WI.

Background: Frailty, characterized by physiologic depletion, predicts postoperative morbidity and mortality in vascular surgery patients. CT-derived sarcopenia is a valuable method for objectively staging frailty preoperatively.

Purpose: With prior analyses primarily measuring psoas cross-sectional area on CT, we compared a method of measuring thoracic sarcopenia to existing techniques of lumbar sarcopenia and assessed the association with long-term survival and outcomes post-Thoracic Endovascular Aortic Repair (TEVAR).

Methods: Prospectively collected data of 217 patients undergoing TEVAR from 2009 to 2012 were reviewed. Thoracic sarcopenia was quantified by measuring total area of the rectus abdominis, latissimus dorsi, intercostal, erector spinae, and external and internal oblique muscles at the T12 vertebral level. Total psoas area at the L3 was used to measure lumbar sarcopenia.

Results: 200 patients had preoperative imaging enabling measurements of thoracic sarcopenia, 186 of these patients were also assessed for lumbar sarcopenia. Thoracic sarcopenic patients were older, had lower body mass indices, were more commonly female, and most commonly being treated for aneurysms. Thoracic sarcopenic patients had significantly higher rates of congestive heart failure, hypertension, prior vascular intervention, and TEVAR-related adverse events. Thoracic sarcopenia was associated with significantly higher mortality at 2 and 5 years post-TEVAR (2-year mortality: 19% vs 8%, P = 0.02; 5-year mortality: 31% vs 18%, P = 0.03). Lumbar sarcopenia was not associated with increased mortality at any time point. Patients whose muscle mass degraded over 48-month follow-up did not experience significantly higher rates of adverse events.

Conclusions: CT-derived thoracic sarcopenia, but not lumbar sarcopenia, is significantly associated with 5-year mortality post-TEVAR.
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July 2020

A Frailty-Based Risk Score Predicts Morbidity and Mortality After Elective Endovascular Repair of Descending Thoracic Aortic Aneurysms.

Ann Vasc Surg 2020 Aug 6;67:90-99. Epub 2019 Nov 6.

Division of Vascular Surgery, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.

Background: Thoracic endovascular aortic repair (TEVAR) has expanded access to descending thoracic aortic aneurysm (DTAA) repair particularly for elderly and frail patients. This high-risk population has limited long-term overall survival, such that appropriate patient selection is required to optimize patient benefit and resource utilization. Our objective is to develop and validate a frailty-based, procedure-specific risk score for patients undergoing elective TEVAR for DTAA.

Methods: Patients undergoing nonemergent TEVAR for DTAA during 2005-2016 were identified in the National Surgical Quality Improvement Program database. Those with concurrent cardiac or open aortic surgery, abdominal visceral intervention, or Zone 0 deployment were excluded. Patients were randomly divided between derivation and validation samples. The primary outcome was 30-day major adverse events (MAE), including mortality and major systemic complications. Using the derivation cohort, variables associated with MAE were identified by univariable analyses. Those with P < 0.05 were included in multivariable logistic regression analysis. Independent procedure-specific and frailty-related risk factors for MAE were used to develop a pragmatic score to assess risk for TEVAR.

Results: Overall, 1,784 patients were included. 14% of the derivation patients had MAE (14% major complications, 4% mortality). Independent risk factors for MAE were primarily associated with markers of frailty and TEVAR extent and complexity and included functional dependence (OR 2.9, 95% CI 1.6-5.4), pulmonary disease (1.6, 1.1-2.4), thoracoabdominal extent (2.2 (1.4-3.4), need for iliac access (2.1, 1.1-3.8), and Zone I or II deployment (OR 1.7, 1.1-2.5). According to their respective beta coefficients, each variable was assigned a single point. Based on total points, patients were stratified as low- (0 points), intermediate- (1 point), or high-risk (≥2 points), with stepwise increases in mortality (0%, 4%, and 9%) and major complications (7%, 11%, and 23%) between strata. Validation patients had similar characteristics, risk strata distribution, and outcomes as the derivation patients, and the risk model had similar performance in both groups.

Conclusions: Markers of frailty and procedure complexity strongly predict MAE after TEVAR for DTAA and can improve patient selection by enabling patient and procedure-specific risk stratification. While TEVAR is safe in low-risk patients, intermediate-risk patients warrant careful discussion of the risks and benefits of aortic intervention; under certain circumstances, high-risk patients may not benefit. Further study is required to define the association between frailty and long-term outcomes.
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August 2020

Derivation and validation of thoracic sarcopenia assessment in patients undergoing thoracic endovascular aortic repair.

J Vasc Surg 2019 05 28;69(5):1379-1386. Epub 2018 Dec 28.

Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisc.

Objective: Sarcopenia, as assessed by computed tomography (CT)-based measurements of muscle mass, is an objective and patient-specific indicator of frailty, which is an important predictor of operative morbidity and mortality. Studies to date have primarily focused on psoas-defined sarcopenia, which may not be valid among patients with thoracic aortic disease. Using psoas sarcopenia as the reference for sarcopenia, the purpose of this study was to create and to validate a new thoracic-level method of measuring sarcopenia as a novel method to assess frailty among patients undergoing thoracic endovascular aortic repair.

Methods: Prospectively collected data of patients undergoing thoracic endovascular aortic repair for thoracic aortic dissection, aneurysm, or injury using a conformable thoracic graft were reviewed. Patients with preoperative abdominal and thoracic CT imaging were included. Thoracic muscle mass was measured on axial images at the T12 level using our newly established standardized computer-assisted protocol. Psoas sarcopenia was measured at the L3 level using standard methods. Optimal sex-specific diagnostic T12 measurements were determined by receiver operating characteristic (ROC) curve analysis. A subset of scans were reviewed in duplicate by two trained observers and intraobserver and interobserver reliability tested by intraclass correlation coefficient. Agreement between T12 and L3 sarcopenia was tested by Cohen κ (scale, 0-1).

Results: There were 147 patients included for analysis, including 34 dissection, 80 trauma, and 33 aneurysm patients. ROC curve analysis yielded sarcopenic cutoff values of 106.00 cm/m for women and 110.00 cm/m for men at the T12 level. Based on ROC curve analysis, overall accuracy of T12 measurements was high (area under ROC curve, 0.91 for men and 0.90 for women). Quantitative interobserver and intraobserver reliability yielded excellent intraclass correlation coefficient values (>0.95). Qualitative interobserver reliability yielded nearly perfect Cohen κ values (>0.85). Qualitative intraobserver reliability of calculating sarcopenia at both the T12 and L3 levels was fair for both readers (0.361 and 0.288). There was additionally a general correlation between changes in muscle area at L3 with changes at T12 during 48 months.

Conclusions: Thoracic sarcopenia can be readily and reliably reproduced from CT-derived measurement of T12-level muscle area. This approach may be used as an alternative method to objectively define sarcopenia in patients without abdominal CT imaging. Future studies to assess the predictability of thoracic vs abdominal sarcopenia on postoperative outcomes will enhance the utility of these tools.
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May 2019