Louis W. Wang

Cardiac Testing for Coronary Artery Disease in Potential Kidney Transplant Recipients: A Systematic Review of Test Accuracy Studies

BACKGROUND Cardiovascular disease is the leading cause of death after kidney transplant. Screening for coronary artery disease is integral to pretransplant evaluation, although the relative performance of different tests is uncertain. STUDY DESIGN Systematic review of diagnostic test accuracy studies using hierarchical summary receiver operating characteristic analysis. SETTING & POPULATION Kidney transplant candidates undergoing pretransplant assessment. SELECTION CRITERIA OF STUDIES: Studies evaluating the accuracy of screening tests for detecting coronary artery disease. INDEX TESTS Any non- or minimally invasive test used to diagnose coronary artery disease. REFERENCE TEST Coronary angiography. RESULTS 11 studies (690 participants) evaluated dobutamine stress echocardiography; 7 (317 participants), myocardial perfusion scintigraphy; 2 (129 participants), exercise stress electrocardiography; and 2 (121 participants), other tests. Dobutamine stress echocardiography had pooled sensitivity of 0.80 (95% CI, 0.64-0.90) and specificity of 0.89 (95% CI, 0.79-0.94). Myocardial perfusion scintigraphy had pooled sensitivity of 0.69 (95% CI, 0.48-0.85) and specificity of 0.77 (95% CI, 0.59-0.89). Head-to-head comparison of dobutamine stress echocardiography and myocardial perfusion scintigraphy (2 studies; 116 participants) showed that dobutamine stress echocardiography had higher specificity and at least equivalent or higher sensitivity. Indirect comparison suggested dobutamine stress echocardiography may have improved accuracy over myocardial perfusion scintigraphy (P = 0.07). LIMITATIONS Power to detect differences in accuracy between tests is limited due to sparse data. Absence of significant coronary artery disease may not necessarily correlate with cardiac event-free survival after transplant. CONCLUSIONS Dobutamine stress echocardiography may perform better than myocardial perfusion scintigraphy; however, additional studies directly comparing dobutamine stress echocardiography and myocardial perfusion scintigraphy are needed. Further research should focus on assessing the ability of functional tests to predict postoperative outcome.

Treatment of recurrent corneal erosion syndrome using the combination of oral doxycycline and topical corticosteroid.

Recurrent corneal erosion syndrome is a debilitating condition for which there are many treatment options with varying rates of success. One treatment of interest in recent years is the combination of oral doxycycline and topical corticosteroids, both of which have been shown to inhibit key metalloproteinases important to disease pathogenesis. To assess the efficacy of this treatment, we conducted a retrospective single‐observer case series involving all patients with recurrent corneal erosion syndrome who were treated at a community‐based clinic with oral doxycycline and topical corticosteroid between January 2000 and July 2007. Twenty‐one patients were identified. All received oral doxycycline 50 mg twice daily and topical fluoromethalone 0.1% three times daily for at least 4 weeks. At 8 weeks post commencement of treatment, 15/21 patients (71%) were symptom free. All but one of these patients reported an improvement in symptoms. Of those patients not lost to follow up, 15/18 patients (83%) and 11/15 patients (73%) denied any symptoms suggestive of relapse at 6 and 12 months, respectively. Among the patients in remission was one who had responded poorly to other treatments including ocular lubricants, epithelial debridement, serum eyedrops, anterior stromal puncture, and phototherapeutic keratectomy. Treatment of recurrent corneal erosion syndrome with the combination of oral doxycycline and topical corticosteroid is effective. It may help patients with recurrent corneal erosion syndrome who have failed other forms of treatment. This non‐invasive treatment modality should also be considered as the first treatment option when conservative management with ocular lubricants fails.

Wound infusion with local anaesthesia after laparotomy: a randomized controlled trial

Background:  The use of a continuous local anaesthesia infusion after laparotomy may reduce opioid requirements and facilitate earlier return of bowel function, independent mobilization and hospital discharge.

Impact of Patient Preparation on the Diagnostic Performance of 18F-FDG PET in Cardiac Sarcoidosis: A Systematic Review and Meta-analysis.

Purpose 18F-FDG PET/CT is a valuable diagnostic tool in the evaluation of cardiac sarcoidosis. Appropriate patient preparation is important because the diagnostic accuracy of this procedure depends on adequate suppression of physiologic glucose uptake. This systematic review and meta-analysis aims to assess the effect of different patient preparations on the diagnostic accuracy of 18F-FDG PET/CT in cardiac sarcoidosis. Patients and Methods We searched the PubMed/MEDLINE, Embase, and Cinicaltrials.gov databases. Sixteen studies (n = 559) were identified to be suitable for this systemic review. Studies were stratified according to fasting duration and means of physiologic suppression of 18F-FDG by cardiac tissue, which involves the use of heparin infusion or high-fat, low-carbohydrate diet before imaging. Study quality was assessed using the QUADAS-2 tool. Forest plots of sensitivity and specificity were calculated in Review Manager 5.3, and a random-effects hierarchical summary receiver operating characteristic model was created using MetaDiSc. Meta-regression was performed to investigate sources of heterogeneity. Results PET/CT had an overall Specificity of 0.75 (95% confidence interval [CI], 0.69–0.80) and specificity of 0.81 (95% CI, 0.76–0.85) for the diagnosis of cardiac sarcoidosis. This modest diagnostic accuracy was attributed to the inclusion of large single study in which a short fasting duration before scanning likely influenced its sensitivity. Its exclusion resulted in an overall sensitivity of 0.81 (95% CI, 0.76–0.86) and specificity of 0.82 (95% CI, 0.77–0.86). Meta-regression showed that the diagnostic odds ratio was significantly affected by fasting time and heparin administration before scanning (P = 0.01, 0.02) but not with high-fat, low-carbohydrate diet (P = 0.17). Conclusions 18F-FDG PET/CT plays an integral role in the diagnosis of cardiac sarcoidosis. Diagnostic accuracy is affected by fasting duration and means of cardiomyocyte glucose uptake suppression before scanning.

Long-term biventricular HeartWare ventricular assist device support—Case series of right atrial and right ventricular implantation outcomes

BACKGROUND There is limited information on outcomes using the HeartWare ventricular assist device (HVAD; HeartWare, Framington, MA) as a biventricular assist device, especially with respect to site of right ventricular assist device (RVAD) implantation. METHODS Outcomes in 13 patients with dilated cardiomyopathy and severe biventricular failure who underwent dual HVAD implantation as bridge to transplantation between August 2011 and October 2014 were reviewed. RESULTS Of 13 patients, 10 were Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Level 1, and 3 were INTERMACS Level 2. Mean age was 45 ± 11 years, and mean body mass index was 26 ± 4 kg/m(2). There were 7 patients on temporary mechanical support pre-operatively (extracorporeal life support, n = 5; intra-aortic balloon pump, n = 2). The median hospital length of stay was 53 days (interquartile range [IQR] 33-70 days) with a median intensive care unit length of stay of 14 days (IQR 8-36 days). The median length of support on device was 269 days (IQR 93-426 days). The right HVAD was implanted in the right ventricular (RV) free wall in 6 patients and in the right atrial (RA) free wall in 7 patients. Transplantation was successfully performed in 5 patients, and overall survival for the entire cohort was 54%. RVAD pump thrombosis occurred in 3 of 6 RV pumps and 1 of 7 RA pumps. No left ventricular assist device pump thrombosis was observed. Bleeding tended to be higher in the RV implantation group (3 of 6 vs 0 of 7). During follow up, 6 patients died (4 of 7 in the RA group vs 2 of 6 in the RV group). Cause of death was multiple-organ failure in 3 patients, sepsis in 2 patients, and intracerebral hemorrhage in 1 patient. CONCLUSIONS Critically ill patients who require biventricular support can be successfully bridged to transplant using 2 HVADs. RA implantation may allow right heart support with lower pump thrombosis and bleeding complications, although this was at the expense of a higher mortality in this cohort.

Prognostic value of cardiac tests in potential kidney transplant recipients: a systematic review.

Background Whether abnormal myocardial perfusion scintigraphy (MPS), dobutamine stress echocardiography (DSE) or coronary angiography, performed during preoperative evaluation for potential kidney transplant recipients, predicts future cardiovascular morbidity is unclear. We assessed test performance for predicting all-cause mortality, cardiovascular mortality and major adverse cardiac events (MACE). Methods We searched MEDLINE and EMBASE (to February 2014), appraised studies, and calculated risk differences and relative risk ratios (RRR) with 95% confidence intervals (95% CI) using random effects meta-analysis. Results Fifty-two studies (7401 participants) contributed data to the meta-analysis. Among the different tests, similar numbers of patients experienced MACE after an abnormal test result compared with a normal result (risk difference: MPS 20 per 100 patients tested [95% CI, 0.11–0.29], DSE 24 [95% CI, 0.10–0.38], and coronary angiography 20 [95% CI, 0.08–0.32; P = 0.91]). Although there was some evidence that coronary angiography was better at predicting all-cause mortality than MPS (RRR, 0.69; 95% CI, 0.49–0.96; P = 0.03) and DSE (RRR, 0.72; 95% CI, 0.50–1.02; P = 0.06), noninvasive tests were as good as coronary angiography at predicting cardiovascular mortality (RRR, MPS, 0.89; 95% CI, 0.38–2.10; P = 0.78; DSE, 1.09; 95% CI, 0.12–10.05; P = 0.93), and MACE (RRR: MPS, 1.09; 95% CI, 0.64–1.86; P = 0.74; DSE, 1.56; 95% CI, 0.71–3.45; P = 0.25). Conclusions Noninvasive tests are as good as coronary angiography at predicting future adverse cardiovascular events in advanced chronic kidney disease. However, a substantial number of people with negative test results go on to experience adverse cardiac events.

Standardized echocardiographic assessment of cardiac function in normal adult zebrafish and heart disease models

ABSTRACT The zebrafish (Danio rerio) is an increasingly popular model organism in cardiovascular research. Major insights into cardiac developmental processes have been gained by studies of embryonic zebrafish. However, the utility of zebrafish for modeling adult-onset heart disease has been limited by a lack of robust methods for in vivo evaluation of cardiac function. We established a physiological protocol for underwater zebrafish echocardiography using high frequency ultrasound, and evaluated its reliability in detecting altered cardiac function in two disease models. Serial assessment of cardiac function was performed in wild-type zebrafish aged 3 to 12 months and the effects of anesthetic agents, age, sex and background strain were evaluated. There was a varying extent of bradycardia and ventricular contractile impairment with different anesthetic drugs and doses, with tricaine 0.75 mmol l−1 having a relatively more favorable profile. When compared with males, female fish were larger and had more measurement variability. Although age-related increments in ventricular chamber size were greater in females than males, there were no sex differences when data were normalized to body size. Systolic ventricular function was similar in both sexes at all time points, but differences in diastolic function were evident from 6 months onwards. Wild-type fish of both sexes showed a reliance on atrial contraction for ventricular diastolic filling. Echocardiographic evaluation of adult zebrafish with diphtheria toxin-induced myocarditis or anemia-induced volume overload accurately identified ventricular dilation and altered contraction, with suites of B-mode, ventricular strain, pulsed-wave Doppler and tissue Doppler indices showing concordant changes indicative of myocardial hypocontractility or hypercontractility, respectively. Repeatability, intra-observer and inter-observer correlations for echocardiographic measurements were high. We demonstrate that high frequency echocardiography allows reliable in vivo cardiac assessment in adult zebrafish and make recommendations for optimizing data acquisition and analysis. This enabling technology reveals new insights into zebrafish cardiac physiology and provides an imaging platform for zebrafish-based translational research. Summary: Standardization of zebrafish echocardiography provides insights into cardiac physiology in normal and diseased states, with application for functional studies in zebrafish models of heart disease.

Late surgical explantation and aortic valve replacement after transcatheter aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) in patients with bicuspid aortic valve disease is associated with higher rates of paravalvular aortic regurgitation, which may require subsequent surgical correction. We report a case of successful late surgical CoreValve explantation 1,389 days after TAVI in a patient with bicuspid aortic valve stenosis and McArdles disease who developed severe paravalvular aortic regurgitation. We confirm that neoendothelialization and incorporation of the nitinol cage into the aortic wall had occurred at nearly 4 years postimplantation, although explantation with careful endarterectomy could still be performed without requiring simultaneous aortic root replacement.

Piecewise output feedback controller synthesis of discrete time fuzzy systems

This paper presents an observer-based output feedback controller design method for discrete time Takagi-Sugeno fuzzy systems, using a discrete time piecewise Lyapunov function. The proposed piecewise output feedback fuzzy controller is made up of a piecewise state feedback fuzzy controller and observer for each subspace. The validity of such a scheme involving the separation principle is verified by a piecewise Lyapunov function. It is shown that the state feedback control laws and observer gains can be obtained by solving a set of linear matrix inequalities (LMI) that is numerically tractable with commercially available software. An example is given to demonstrate the advantage of the proposed method.

Severe carbon monoxide poisoning from waterpipe smoking: a public health concern.

A 20-year-old woman was brought by ambulance to the emergency department of a district hospital after an episode of presyncope. She described symptoms of severe light-headedness, mild headache and nausea, but denied experiencing weakness or sensory disturbances. Seizure activity was not reported. She had used a waterpipe for 1 hour before the onset of symptoms. Although this was her first hospital presentation with these symptoms, she had frequently experienced queasiness and light-headedness after using a waterpipe, which she did on most days of the week, each session lasting about 45 to 60 minutes. She denied depression, suicidal ideation, and recent alcohol or drug use.