Arthur W Wallace

Arthur W Wallace
San Francisco VA Medical Center | VAMC · Department of Anesthesia

MD, PhD

About

95
Publications
4,976
Reads
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7,130
Citations
Citations since 2017
14 Research Items
985 Citations
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Additional affiliations
January 1993 - present
San Francisco VA Medical Center
Position
  • Chief of Anesthesia
January 1993 - present
San Francisco VA Medical Center
Position
  • Chief of Anesthesia Service
July 1988 - present
University of California, San Francisco
Position
  • Professor (Full)
Education
July 1992 - July 1993
University of California, San Francisco
Field of study
  • Cardiac Anesthesia
July 1988 - June 1992
University of California, San Francisco
Field of study
  • Anesthesiology
June 1981 - June 1988
Johns Hopkins Medicine
Field of study
  • Biomedical Engineering and Medicine

Publications

Publications (95)
Article
Full-text available
Objectives SARS-CoV-2 enters cells using the ACE2 receptor. Medications that affect ACE2 expression or function such as angiotensin receptor blockers (ARBs) and ACE inhibitors (ACE-I) and metformin have the potential to counter the dysregulation of ACE2 by the virus and protect against viral injury. Here, we describe COVID-19 survival associated wi...
Article
Introduction Finite element (FE) mechanics models of the heart are becoming more sophisticated. However, there is lack of consensus about optimal element type and coupling of FE models to the circulation. We describe biventricular (left (LV) and right (RV) ventricles) FE mechanics model creation using hexahedral elements, airbags and a functional m...
Article
Purpose Myocardial strain is increasingly used to assess left ventricular (LV) function. Incorporation of LV deformation into finite element (FE) modeling environment with subsequent strain calculation will allow analysis to reach its full potential. We describe a new kinematic model-based analysis framework (KMAF) to calculate strain from 3D cine-...
Article
Introduction Left ventricular (LV) diastolic dysfunction (DD) is common after myocardial infarction (MI). Whereas current clinical assessment of DD relies on indirect markers including LV filling, finite element (FE) -based computational modeling directly measures regional diastolic stiffness. We hypothesized that inverse deformation gradient (DG)...
Article
Full-text available
The left ventricular (LV) end-systolic (ES) pressure volume relationship (ESPVR) is the cornerstone of systolic LV function analysis. We describe a 2D real-time (RT) MRI-based method (RTPVR) with separate software tools for 1) semi-automatic level set-based shape prior method (LSSPM) of the LV, 2) generation of synchronized pressure area loops and...
Article
The decrease in contractility in myocardium adjacent (border zone; BZ) to a myocardial infarction (MI) is correlated with an increase in reactive oxygen species (ROS). We hypothesized that injection of a thermoresponsive hydrogel, with ROS scavenging properties, into the MI would decrease ROS and improve BZ function. Fourteen sheep underwent antero...
Article
Background: In the United States, opioids are commonly prescribed to treat knee pain after total knee arthroplasty (TKA). While surgery leads to decreased pain in most patients, a sizable minority continue to experience severe pain and consume opioids chronically after TKA. We sought to determine the population-level effect of TKA on opioid consum...
Preprint
The left ventricular (LV) end-systolic pressure volume relationship (ES; ESPVR) is the cornerstone of systolic LV function analysis. Recently, it became possible to measure 2D LV chamber shape during vena cava occlusion (VCO) with MRI. We used an improved level-set semi-automatic segmentation method (LSSM) to determine the effect of VCO on LV geome...
Article
Full-text available
Introduction Cigarette smoking by surgical patients is associated with increased complications. E-cigarettes have emerged as a potential smoking cessation tool. We sought to determine the feasibility and acceptability of e-cigarettes, compared to nicotine patch, for perioperative smoking cessation in veterans. Methods Preoperative patients were ra...
Data
NJOY electronic nicotine delivery device provided to participants in the END group Each participant in the END group was issued 6-weeks of NJOY e-cigarettes, pictured above. The number of e-cigarettes issued corresponded to their baseline smoking, with 1 NJOY e-cigarette equivalent to 10 cigarettes per day. Participants were given 3 weeks of Bold (...
Data
Smoking by END and NRT groups at enrollment, day of surgery, 8-week visit, and 6-month phone call Boxplots indicating distribution of cigarettes smoked per day at baseline (Preoperative Clinic visit), day of surgery, 8-week, and 6-month follow-up visits. There were no statistically significant differences between groups END and NRT at any time poin...
Article
Full-text available
Decreased contractility in the non-ischemic border zone surrounding a MI is in part due to degradation of cardiomyocyte sarcomeric components by intracellular matrix metalloproteinase-2 (MMP-2). We recently reported that MMP-2 levels were increased in the border zone after a MI and that treatment with doxycycline for two weeks after MI was associat...
Article
Sevoflurane vaporizers (GE Tec 7) were difficult to fill with "slow flow" and a need to "burp." Evaluation of the bottle of sevoflurane (AbbVie Ultane) demonstrated a contaminant. Four of the facilities' 13 sevoflurane vaporizers had the contaminant. Unopened sevoflurane bottles did not have evidence of contamination. The contaminant was found to b...
Article
Full-text available
Background: Chronic ischemic mitral regurgitation (CIMR) is associated with poor outcome. Left ventricular (LV) strain after posterolateral myocardial infarction (MI) may drive LV remodeling. Although moderate CIMR has been previously shown to affect LV remodeling, the effect of CIMR on LV strain after posterolateral MI remains unknown. We tested...
Article
Despite widespread use, there is limited information to guide perioperative management of angiotensin receptor blockers (ARBs). In this retrospective cohort study, the authors evaluated the patterns of postoperative ARB use in veterans regularly prescribed ARBs admitted for noncardiac surgery at the Veterans Affairs Healthcare system between 1999 a...
Article
Full-text available
Background Preoperative β-blockade has been posited to result in better outcomes for vascular surgery patients by attenuating acute hemodynamic changes associated with stress. However, the incremental effectiveness, if any, of β-blocker usage in blunting heart rate responsiveness for vascular surgery patients who avoid general anesthesia remains un...
Article
BACKGROUND Angiotensin-converting enzyme inhibitors (ACE-Is) are a widely used class of cardiovascular medication. However, limited data exist on the risks of postoperative nonresumption of an ACE-I.OBJECTIVE To evaluate the factors and 30-day mortality risks associated with the postoperative nonresumption of an ACE-I.DESIGNA retrospective cohort s...
Article
Background: Contractility in the borderzone (BZ) after anteroapical myocardial infarction (MI) is depressed. We tested the hypothesis that BZ contractility is also decreased after posterolateral MI. Methods: Five sheep underwent posterolateral MI. Magnetic resonance imaging (MRI) was performed 2 weeks before and 16 weeks after MI, and left ventr...
Article
Cardiac imaging using magnetic resonance requires a gating signal in order to compensate for motion. Human patients are routinely scanned using an electrocardiogram (ECG) as a gating signal during imaging. However, we found that in sheep the ECG is not a reliable method for gating. We developed a software based method that allowed us to use the lef...
Article
Lalmohamed et al1 used epidemiologic analysis to test the association between total hip replacement (THR) or total knee replacement (TKR) and acute myocardial infarction (AMI). Not surprisingly, during the first 2 postoperative weeks, the risk of AMI was elevated in both populations of patients undergoing THR or TKR. The risk was elevated for 6 wee...
Article
Full-text available
Objectives: Contractile function in the normally perfused infarct borderzone (BZ) is depressed. However, the impact of reduced BZ contractility on left ventricular (LV) pump function is unknown. As a consequence, there have been no therapies specifically designed to improve BZ contractility. We tested the hypothesis that an improvement in borderzo...
Article
Undersized mitral annuloplasty (MA) is the preferred surgical treatment for chronic ischemic mitral regurgitation. However, the preferred shape of undersized MA is unclear. A previously described finite element model of the left ventricle with mitral valve based on magnetic resonance images of a sheep with chronic ischemic mitral regurgitation afte...
Article
Full-text available
Numerical modelling of the cardiovascular system is becoming an important tool for assessing the influence of heart disease and treatment therapies. In the current study, we present an approach for modelling the interaction between the heart and the circulatory system. This was accomplished by creating animal-specific biventricular finite element (...
Article
To investigate the association of preoperative β-blocker usage and maximal heart rates observed during the induction of general anesthesia. Retrospective descriptive, univariate, and multivariate analyses of electronic hospital and anesthesia medical records. A tertiary-care medical center within the Veterans Health Administration. Consecutive adul...
Article
Chronic ischemic mitral regurgitation (MR) is associated with poor outcome. However, the effect of chronic ischemic MR on left ventricular (LV) remodeling after posterolateral myocardial infarction (MI) remains controversial. We tested the hypothesis that moderate MR accelerates LV remodeling after posterolateral MI. Posterolateral MI was created i...
Article
Full-text available
Homogeneous contractility is usually assigned to the remote region, border zone (BZ), and the infarct in existing infarcted left ventricle (LV) mathematical models. Within the LV, the contractile function is therefore discontinuous. Here, we hypothesize that the BZ may in fact define a smooth linear transition in contractility between the remote re...
Conference Paper
According to recent statistics from the American Heart Association, Heart Failure (HF) affects 5.7 million Americans [1]. HF is characterized by the global dilation of the heart, which leads to an increase in ventricular volume and a reduction in pumping efficiency. Several treatment strategies have been investigated to combat the adverse remodelin...
Article
An abstract is unavailable. This article is available as HTML full text and PDF.
Article
Full-text available
Recently, a noninvasive method for determining regional myocardial contractility, using an animal-specific finite element (FE) model-based optimization, was developed to study a sheep with anteroapical infarction (Sun et al., 2009, "A Computationally Efficient Formal Optimization of Regional Myocardial Contractility in a Sheep With Left Ventricular...
Article
The Atenolol study of 1996 provided evidence that perioperative β-blockade reduced postsurgical mortality. In 1998, the indications for perioperative β-blockade were codified as the Perioperative Cardiac Risk Reduction protocol and implemented at the San Francisco Veterans Affairs Medical Center. The current study tested the following hypothesis: I...
Article
Full-text available
Both the Young-Laplace law and finite element (FE) based methods have been used to calculate left ventricular wall stress. We tested the hypothesis that the Young-Laplace law is able to reproduce results obtained with the FE method. Magnetic resonance imaging scans with noninvasive tags were used to calculate three-dimensional myocardial strain in...
Article
The 1996 atenolol study provided evidence that perioperative β-adrenergic receptor blockade (β-blockade) reduced postsurgical mortality. In 1998, the indications for perioperative β-blockade were codified as the Perioperative Cardiac Risk Reduction protocol and implemented at the San Francisco Veterans Administration Medical Center, San Francisco,...
Conference Paper
Ischemic mitral regurgitation (MR) affects 1.2 to 2.1 million patients in the United States, with more than 400,000 patients having moderate-to-severe MR [1]. As a consequence of left ventricular remodeling after postero-basal myocardial infarction (MI), the posterior papillary muscle moves laterally. This causes both anterior and posterior mitral...
Article
Left ventricular remodeling after posterobasal myocardial infarction can lead to ischemic mitral regurgitation. This occurs as a consequence of leaflet tethering due to posterior papillary muscle displacement. A finite element model of the left ventricle, mitral apparatus, and chordae tendineae was created from magnetic resonance images from a shee...
Article
Full-text available
Endoventricular patch plasty (Dor) is used to reduce left ventricular volume after myocardial infarction and subsequent left ventricular remodeling. End-diastolic and end-systolic pressure-volume and Starling relationships were measured, and magnetic resonance images with noninvasive tags were used to calculate 3-dimensional myocardial strain in 6...
Article
Full-text available
A non-invasive method for estimating regional myocardial contractility in vivo would be of great value in the design and evaluation of new surgical and medical strategies to treat and/or prevent infarction-induced heart failure. As a first step towards developing such a method, an explicit finite element (FE) model-based formal optimization of regi...
Article
Linear repair of left ventricular aneurysm has been performed with mixed clinical results. By using finite element analysis, this study evaluated the effect of this procedure on end-systolic stress. Nine sheep underwent myocardial infarction and aneurysm repair with a linear repair (13.4 +/- 2.3 weeks postmyocardial infarction). Satisfactory magnet...
Article
Endoventricular patch plasty (Dor procedure) has gained favor as a surgical treatment for heart failure associated with large anteroapical myocardial infarction. We tested the hypotheses that the Dor procedure increases systolic circumferential shortening and longitudinal shortening in noninfarcted left ventricular regions in sheep. In 6 male Dorse...
Article
Measures of left ventricular (LV) contractility must be linear, load-independent, free of hysteresis, and sensitive to changes in inotropic state. These properties of measures of LV contractility have been assessed previously in animals, but never in man. Using a micromanometer and volume conductance catheter technology, we measured LV pressure and...
Article
Perioperative cardiac risk reduction using perioperative beta-blockade is being widely adopted. Recent research has identified a second-line agent, perioperative clonidine, that can be used to reduce the risk of perioperative cardiac mortality. Perioperative clonidine has some advantages over perioperative beta-blockers because it has less risk of...
Article
Although repair of left ventricular aneurysm has been extensively studied, its effect on regional ventricular function remains unclear. The primary goal of this study was to quantify the effect of anteroapical aneurysm plication on systolic deformation in noninfarcted adjacent (border zone) and remote left ventricular regions in sheep. Eight sheep...
Article
Full-text available
The majority of patients undergoing surgical treatment for ST-elevation myocardial infarction receive antifibrinolytic therapy to limit blood loss. This approach appears counterintuitive to the accepted medical treatment of the same condition--namely, fibrinolysis to limit thrombosis. Despite this concern, no independent, large-scale safety assessm...
Article
Endoventricular patch plasty (the Dor procedure) has gained favor as a surgical treatment for heart failure associated with large anteroapical myocardial infarction. We tested the hypothesis that the Dor procedure reduces left ventricular volume, increases end-systolic elastance, decreases diastolic compliance, and maintains left ventricular functi...
Article
Full-text available
Tagged MRI and finite-element (FE) analysis are valuable tools in analyzing cardiac mechanics. To determine systolic material parameters in three-dimensional stress-strain relationships, we used tagged MRI to validate FE models of left ventricular (LV) aneurysm. Five sheep underwent anteroapical myocardial infarction (25% of LV mass) and 22 wk late...
Article
Full-text available
Infarcted segments of myocardium demonstrate functional impairment ranging in severity from hypokinesis to dyskinesis. We sought to better define the contributions of passive material properties (stiffness) and active properties (contracting myocytes) to infarct thickening. Using a finite-element (FE) model, we tested the hypothesis that infarcted...
Article
It has been proposed that successful left ventricular surgical restoration should restore normal helical myofiber orientation. A magnetic resonance imaging technique, magnetic resonance diffusion tensor imaging, has been developed to measure myocyte orientation. By using magnetic resonance diffusion tensor imaging, this study tested the hypothesis...
Article
Surgical anterior ventricular restoration (SAVER) has been proposed for dilated ischemic cardiomyopathy with an akinetic distal anterior left ventricular wall. We tested the hypothesis that SAVER increases stroke volume, reduces mean myofiber stress and achieves optimal results without a patch. A finite element model of the left ventricle (LV) with...
Article
Full-text available
Perioperative myocardial ischemia occurs in 20-40% of patients at risk for cardiac morbidity and is associated with a ninefold increase in risk of cardiac morbidity. In a prospective, double-blinded, clinical trial, we studied 190 patients with or at risk for coronary artery disease in two study groups with a 2:1 ratio (clonidine, n = 125 vs. place...
Article
The Myocor Myosplint is a transcavitary tensioning device designed to change left ventricular (LV) shape and reduce wall stress. Regional wall stress cannot be measured in the intact heart and LV function after surgical remodeling is often confounded by inotropic agents and mitral repair. We used a realistic mathematical (finite element) model of t...
Article
Surgical therapies for heart failure that reduce left ventricular (LV) size have failed to improve LV function. Recent reports describe the direct injection of myocytes into the LV wall and suggest that myocyte transplantation improves regional contractile ability and improves LV function. Using a previously described finite element model, we simul...
Article
Full-text available
Myocardial infarct expansion and left ventricular (LV) remodeling are integral components in the evolution of chronic heart failure and predict morbidity and mortality. Radiofrequency (RF) heating and patch placement of chronic LV aneurysms caused a sustained reduction in LV infarct area and volume in an ovine infarct model. This study evaluated th...
Article
Residual stress is the stress (force per unit area) that remains when all external loads (eg, left ventricular chamber and pericardial pressures) are removed. It has been suggested that ventricular volume reduction surgery can reconstitute the residual stress-strain state of the left ventricle. To determine the extent to which residual stress is in...
Article
There are numerous cardiac and pulmonary complications that can occur after operations that involve the use of cardiopulmonary bypass (CPB). We have chosen to focus on perioperative myocardial ischemia, left ventricular (LV) dysfunction, ventricular arrhythmias, atrial arrhythmias, and inflammation and pulmonary dysfunction as the most important. I...
Article
This study tested the hypothesis that induction and reperfusion with warm substrate-enriched (IRWSE) blood cardioplegia improves postoperative left ventricular (LV) function in patients undergoing elective coronary bypass surgery (CABG). After giving informed consent, 67 patients scheduled for CABG surgery were randomized to either IRWSE + cold blo...
Article
Myocardial infarct expansion and subsequent left ventricular remodeling are associated with increased incidence of congestive failure and mortality. Collagen is known to denature and contract when heated above 65 degrees C. We therefore tested the hypothesis that radio frequency heating of myocardial infarct tissue with application of a restraining...
Article
Unlabelled: We tested the hypothesis that L-arginine (the substrate for nitric oxide production)-combined with amrinone, milrinone (Type III phosphodiesterase [PDE] inhibitors), zaprinast, or sildenafil (Type V PDE inhibitors)-would vasodilate synergistically. Internal mammary artery segments were excised from anesthetized swine, divided into ring...
Article
The endotracheal cardiac output monitor (ECOM) is a new device that uses an endotracheal tube with multiple electrodes to measure cardiac output (CO). It measures the changes in electrical impedance caused by pulsatile blood flow in the aorta. The system was tested for safety and efficacy in 10 swine. Swine (60-80 kg) were chronically instrumented...
Article
The success of left ventricular aneurysm plication depends on how the procedure affects both end-systolic elastance and diastolic compliance and how those changes affect ventricular function (stroke work/end-diastolic volume [PRSW] and stroke volume/end-diastolic pressure [Starling] relationships). Five male Dorsett sheep were surgically instrument...
Article
Partial ventriculectomy (PV) has been proposed by Batista and colleagues to improve cardiac function in patients with dilated cardiomyopathy (DCM); however, results have been mixed. We tested the hypothesis that preoperative diastolic function affects the stroke volume/end-diastolic pressure (Starling) relationship after PV. A previously described...
Article
Nitric oxide-dependent factors (serotonin, activated platelets, acetylcholine) cause vasodilation in normal coronary arteries but vasoconstrict atherosclerotic vessels. This experiment tested the hypothesis that intravenous systemic infusions of L-arginine, a precursor for nitric oxide production, dilate the coronary vascular bed of patients underg...
Article
Partial ventriculectomy (PV) has been proposed by Batista and colleagues to improve cardiac function in patients with dilated cardiomyopathy (DCM); however, results have been mixed. We tested the hypothesis that preoperative diastolic function affects the stroke volume/end-diastolic pressure (Starling) relationship after PV. A previously described...
Article
Ventricular volume reduction surgery has been proposed by Batista to improve cardiac function in patients with dilated cardiomyopathy. However, limited clinical data exist to determine the efficacy of this operation. A finite element simulation is therefore used to determine the effect of volume reduction surgery on left ventricular end-systolic el...
Article
An abstract is unavailable. This article is available as HTML full text and PDF.
Article
Perioperative myocardial ischemia occurs in 20-40% of patients at risk for cardiac complications and is associated with a ninefold increase in risk for perioperative cardiac death, myocardial infarction, or unstable angina, and a twofold long-term risk. Perioperative atenolol administration reduces the risk of death for as long as 2 yr after surger...