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Featured researches published by Amit R. Patel.


Heart Rhythm | 2014

HRS expert consensus statement on the diagnosis and management of arrhythmias associated with cardiac sarcoidosis.

David H. Birnie; William H. Sauer; Frank Bogun; Joshua M. Cooper; Daniel A. Culver; Claire S. Duvernoy; Marc A. Judson; Jordana Kron; Davendra Mehta; Jens Cosedis Nielsen; Amit R. Patel; Tohru Ohe; Pekka Raatikainen; Kyoko Soejima

David H. Birnie, MD (Chair), William H. Sauer, MD, FHRS, CCDS (Chair), Frank Bogun, MD, Joshua M. Cooper, MD, FHRS, Daniel A. Culver, DO,* Claire S. Duvernoy, MD, Marc A. Judson, MD, Jordana Kron, MD, Davendra Mehta, MD, PhD, FHRS, Jens Cosedis Nielsen, MD, Amit R. Patel, MD, Tohru Ohe, MD, FHRS, Pekka Raatikainen, MD, Kyoko Soejima, MD From the University of Ottawa Heart Institute, Ottawa, Ontario, Canada, University of Colorado, Aurora, Colorado, University of Michigan, Ann Arbor, Michigan, Temple University Health System, Philadelphia, Pennsylvania, Cleveland Clinic, Cleveland, Ohio, VA Ann Arbor Healthcare System and University of Michigan, Ann Arbor, Michigan, Albany Medical College, Albany, New York, Virginia Commonwealth University, Richmond, Virginia, Mount Sinai School of Medicine, New York, New York, Aarhus University Hospital, Aarhus, Denmark, University of Chicago, Chicago, Illinois, Sakakibara Heart Institute of Okayama, Okayama, Japan, Heart Center, Tampere University Hospital, Tampere, Finland, and Kyorin University School of Medicine, Mitaka City, Japan.


Journal of the American College of Cardiology | 2010

Assessment of Advanced Coronary Artery Disease: Advantages of Quantitative Cardiac Magnetic Resonance Perfusion Analysis

Amit R. Patel; Patrick F. Antkowiak; Kiran R. Nandalur; Amy M West; Michael Salerno; Vishal Arora; John M Christopher; Frederick H. Epstein; Christopher M. Kramer

OBJECTIVES The purpose of this paper was to compare quantitative cardiac magnetic resonance (CMR) first-pass contrast-enhanced perfusion imaging to qualitative interpretation for determining the presence and severity of coronary artery disease (CAD). BACKGROUND Adenosine CMR can detect CAD by measuring perfusion reserve (PR) or by qualitative interpretation (QI). METHODS Forty-one patients with an abnormal nuclear stress scheduled for X-ray angiography underwent dual-bolus adenosine CMR. Segmental myocardial perfusion analyzed using both QI and PR by Fermi function deconvolution was compared to quantitative coronary angiography. RESULTS In the 30 patients with complete quantitative data, PR (mean +/- SD) decreased stepwise as coronary artery stenosis (CAS) severity increased: 2.42 +/- 0.94 for <50%, 2.14 +/- 0.87 for 50% to 70%, and 1.85 +/- 0.77 for >70% (p < 0.001). The PR and QI had similar diagnostic accuracies for detection of CAS >50% (83% vs. 80%), and CAS >70% (77% vs. 67%). Agreement between observers was higher for quantitative analysis than for qualitative analysis. Using PR, patients with triple-vessel CAD had a higher burden of detectable ischemia than patients with single-vessel CAD (60% vs. 25%; p = 0.02), whereas no difference was detected by QI (31% vs. 21%; p = 0.26). In segments with myocardial scar (n = 64), PR was 3.10 +/- 1.34 for patients with CAS <50% (n = 18) and 1.91 +/- 0.96 for CAS >50% (p < 0.0001). CONCLUSIONS Quantitative PR by CMR differentiates moderate from severe stenoses in patients with known or suspected CAD. The PR analysis differentiates triple- from single-vessel CAD, whereas QI does not, and determines the severity of CAS subtending myocardial scar. This has important implications for assessment of prognosis and therapeutic decision making.


Journal of Cardiovascular Magnetic Resonance | 2012

Late gadolinium enhancement cardiovascular magnetic resonance predicts clinical worsening in patients with pulmonary hypertension

Benjamin H. Freed; Mardi Gomberg-Maitland; Sonal Chandra; Victor Mor-Avi; Stuart Rich; Stephen L. Archer; E Bruce Jamison; Roberto M. Lang; Amit R. Patel

BackgroundLate gadolinium enhancement (LGE) occurs at the right ventricular (RV) insertion point (RVIP) in patients with pulmonary hypertension (PH) and has been shown to correlate with cardiovascular magnetic resonance (CMR) derived RV indices. However, the prognostic role of RVIP-LGE and other CMR-derived parameters of RV function are not well established. Our aim was to evaluate the predictive value of contrast-enhanced CMR in patients with PH.MethodsRV size, ejection fraction (RVEF), and the presence of RVIP-LGE were determined in 58 patients with PH referred for CMR. All patients underwent right heart catheterization, exercise testing, and N-terminal pro-brain natriuretic peptide (NT-proBNP) evaluation; results of which were included in the final analysis if performed within 4 months of the CMR study. Patients were followed for the primary endpoint of time to clinical worsening (death, decompensated right ventricular heart failure, initiation of prostacyclin, or lung transplantation).ResultsOverall, 40/58 (69%) of patients had RVIP-LGE. Patients with RVIP- LGE had larger right ventricular volume index, lower RVEF, and higher mean pulmonary artery pressure (mPAP), all p < 0.05. During the follow-up period of 10.2 ± 6.3 months, 19 patients reached the primary endpoint. In a univariate analysis, RVIP-LGE was a predictor for adverse outcomes (p = 0.026). In a multivariate analysis, CMR-derived RVEF was an independent predictor of clinical worsening (p = 0.036) along with well-established prognostic parameters such as exercise capacity (p = 0.010) and mPAP (p = 0.001).ConclusionsThe presence of RVIP-LGE in patients with PH is a marker for more advanced disease and poor prognosis. In addition, this study reveals for the first time that CMR-derived RVEF is an independent non-invasive imaging predictor of adverse outcomes in this patient population.


Circulation-cardiovascular Imaging | 2010

Molecular Imaging of Atherosclerotic Plaques Targeted to Oxidized LDL Receptor LOX-1 by SPECT/CT and Magnetic Resonance

Dayuan Li; Amit R. Patel; Alexander L. Klibanov; Christopher M. Kramer; Mirta Ruiz; Bum-Yong Kang; Jawahar L. Mehta; George A. Beller; David K. Glover; Craig H. Meyer

Background—The oxidized low-density lipoprotein receptor (LDLR) LOX-1 plays a crucial role in atherosclerosis. We sought to detect and assess atherosclerotic plaque in vivo by using single-photon emission computed tomography/computed tomography and magnetic resonance imaging and a molecular probe targeted at LOX-1. Methods and Results—Apolipoprotein E−/− mice fed a Western diet and LDLR−/− and LDLR−/−/LOX-1−/− mice fed an atherogenic diet were used. Imaging probes consisted of liposomes decorated with anti–LOX-1 antibodies or nonspecific immunoglobulin G, 111indium or gadolinium, and 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine fluorescence markers. In vivo imaging was performed 24 hours after intravenous injection (150 &mgr;L) of LOX-1 or nonspecific immunoglobulin G probes labeled with either 111indium (600 &mgr;Ci) or gadolinium (0.075 mmol/kg), followed by aortic excision for phosphor imaging and Sudan IV staining, or fluorescence imaging and hematoxylin/eosin staining. The LOX-1 probe also colocalized with specific cell types, apoptosis, and matrix metalloproteinase-9 expression in frozen aortic sections. Single-photon emission computed tomography/computed tomography imaging of the LOX-1 probe showed aortic arch “hot spots” in apolipoprotein E−/− mice (n=8), confirmed by phosphor imaging. Magnetic resonance imaging showed significant Gd enhancement in atherosclerotic plaques in LDLR−/− mice with the LOX-1 (n=7) but not with the nonspecific immunoglobulin G (n=5) probe. No signal enhancement was observed in LDLR−/−/LOX-1−/− mice injected with the LOX-1 probe (n=5). These results were confirmed by ex vivo fluorescence imaging. The LOX-1 probe bound preferentially to the plaque shoulder, a region with vulnerable plaque features, including extensive LOX-1 expression, macrophage accumulation, apoptosis, and matrix metalloproteinase-9 expression. Conclusions—LOX-1 can be used as a target for molecular imaging of atherosclerotic plaque in vivo. Furthermore, the LOX-1 imaging signal is associated with markers of rupture-prone atherosclerotic plaque.


European Journal of Heart Failure | 2011

Myocardial damage in patients with sarcoidosis and preserved left ventricular systolic function: an observational study

Amit R. Patel; Michael R. Klein; Sonal Chandra; Kirk T. Spencer; Jeanne M. DeCara; Roberto M. Lang; Martin C. Burke; Edward R. Garrity; D. Kyle Hogarth; Stephen L. Archer; Nadera J. Sweiss; John F. Beshai

Late gadolinium enhanced cardiovascular magnetic resonance (LGE‐CMR) is a valuable test to detect myocardial damage in patients with sarcoidosis; however, the clinical significance of LGE in sarcoidosis patients with preserved left ventricular ejection fraction (LVEF) is not defined. We aim to characterize the prevalence of LGE, its associated cardiac findings, and its clinical implications in sarcoidosis patients with preserved LVEF.


Urologic Oncology-seminars and Original Investigations | 2012

Bladder cancer risk from occupational and environmental exposures

Kyle J. Kiriluk; Sandip M. Prasad; Amit R. Patel; Gary D. Steinberg; Norm D. Smith

Approximately 50% of bladder cancer incidence in the United States has been attributed to known carcinogens, mainly from cigarette smoking. Following the identification of this important causative factor, many investigators have attempted to identify other major causes of bladder cancer in the environment. Genetic and epigenetic alterations related to carcinogenesis in the bladder have been linked to environmental and occupational factors unrelated to cigarette smoking and may account for a significant portion of bladder cancer cases in non-smokers. The interaction between genetics and exposures may modulate bladder cancer risk and influence the differing incidence, progression, and mortality of this disease in different genders and races. Comparative molecular studies are underway to measure the relative effects of environment and inheritance to account for observed differences in the epidemiology of bladder cancer. The use of geospatial tools and population-based data will offer further insight into the environmentally-linked causes of bladder cancer.


Heart | 2012

Accuracy of aortic annular measurements obtained from three-dimensional echocardiography, CT and MRI: human in vitro and in vivo studies

Wendy Tsang; Michael G. Bateman; Lynn Weinert; Gian Pellegrini; Victor Mor-Avi; Lissa Sugeng; Hubert Yeung; Amit R. Patel; Alexander J. Hill; Paul A. Iaizzo; Roberto M. Lang

Objectives To determine the accuracy of calcium-containing rings measurements imaged by three-dimensional echocardiography (3DE), multi-slice CT (MSCT) and cardiac magnetic resonance (CMR) under ideal conditions against the true ring dimensions. To compare the accuracy of aortic annulus (AoA) measurements in ex vivo human hearts using 3DE, MSCT and CMR. To determine the accuracy of AoA measurements in an in vivo human model. Design 3DE, MSCT and CMR imaging were performed on 30 calcium-containing rings and 28 explanted human hearts. Additionally, 15 human subjects with clinical indication for MSCT underwent 3DE. Two experts in each modality measured the images. Main outcome measures Bias and intraclass correlation coefficient for accuracy of imaging measurements when compared with actual ring dimensions. Bias, intraclass correlation coefficient and variability were obtained: (1) when comparing explanted human heart AoA measurements from the two remaining imaging modalities with the most accurate one as determined from the ring measurements and (2) in in vivo human AoA measurements. Analysis was repeated on explanted heart subgroups divided by aortic valve Agatston score. Results Against the known ring dimensions, CMR had the highest accuracy and the lowest variability. MSCT measurements had high accuracy but wider variability and 3DE had the lowest accuracy with the largest variability. When 3DE and MSCT were compared with CMR, 3DE underestimated and MSCT overestimated AoA dimensions, but inter-measurement variability of 3DE and MSCT were similar. When divided by Agatston score, both 3DE and MSCT measurements were larger and showed greater variability with increasing calcium burden. The in vivo study showed that the correlation between 3DE and MSCT measurements was high; however, 3DE measurements were smaller than those measured with MSCT. Conclusions In the in vitro model, CMR measurements were the most accurate for assessing the actual dimensions suggesting that further investigations on its role in AoA measurement in TAVR are needed. However from the in vivo model, MSCT and 3DE are reasonable alternatives with the understanding that they can slightly overestimate and underestimate annular dimensions, respectively.


Current Opinion in Urology | 2009

Optimal biopsy strategies for the diagnosis and staging of prostate cancer.

Amit R. Patel; J. Stephen Jones

Purpose of review Prostate biopsy has evolved from a paradigm of a small number of random biopsies to one of systematic, numeric, and anatomic strategy. Over the past several years, the data have demonstrated the importance of purposeful biopsy strategies for detecting, accurately grading, and staging prostate cancer in varying patient populations. We review the optimal strategies for prostate biopsy given various clinical situations. Recent findings The 10–14 core-extended biopsy scheme is optimal for first-time prostate biopsy. In patients with clinical suspicion of prostate cancer but prior negative biopsy, saturation biopsy with a focus on lateral and apical cores may be indicated. Saturation biopsy is not indicated as an initial biopsy strategy, but is efficacious for staging patients undergoing active surveillance protocols due to the risk of pathological upgrading and clinical upstaging after initial biopsy. There remains a high discordance between prostate biopsy and radical prostatectomy Gleason scores; however, extended biopsy schemes may improve concordance rates. Summary Further studies are needed to define the role of extended and saturation biopsy strategies for individualized clinical situations. The goal of current prostate biopsy studies has evolved from one of purely evaluating cancer detection to investigating as to how biopsy results can assist clinical management and predict outcomes for patients with and without prostate cancer.


The Journal of Urology | 2012

The Impact of Mechanical Bowel Preparation on Postoperative Complications for Patients Undergoing Cystectomy and Urinary Diversion

Michael C. Large; Kyle J. Kiriluk; G. Joel DeCastro; Amit R. Patel; Sandip M. Prasad; Gautam Jayram; Stephen G. Weber; Gary D. Steinberg

PURPOSE The benefit of routine mechanical bowel preparation for patients undergoing radical cystectomy is not well established. We compared postoperative complications in patients who did or did not undergo mechanical bowel preparation before radical cystectomy. MATERIALS AND METHODS In 2008 a single surgeon (GDS) performed open radical cystectomy with an ileal conduit or orthotopic neobladder in 105 consecutive patients with preoperative mechanical bowel preparation consisting of 4 l GoLYTELY®. In 2009 radical cystectomy with an ileal conduit or orthotopic neobladder was performed in 75 consecutive patients without mechanical bowel preparation. A comprehensive database provided clinical, pathological and outcome data. RESULTS All patients had complete perioperative data available. The 2 groups were similar in age, Charlson comorbidity score, diversion type, receipt of neoadjuvant radiation or chemotherapy, blood loss, hospital stay, time to diet and pathological stage. Postoperative urinary tract infection, wound dehiscence and perioperative death rates were similar in the 2 groups. Clostridium difficile infection developed within 30 days of surgery in 11 of 105 vs 2 of 75 patients with vs without mechanical bowel preparation (p = 0.08). When adjusted for the annual hospital-wide C. difficile rate, the difference remained insignificant (p = 0.21). Clavien grade 3 or greater abdominal and gastrointestinal complications, including fascial dehiscence, abdominal abscess, small bowel obstruction, bowel leak and entero-diversion fistula, developed in 7 of 105 patients with (6.7%) vs 11 of 75 without (14.7%) mechanical bowel preparation (p = 0.08). CONCLUSIONS The use of mechanical bowel preparation for patients undergoing radical cystectomy with an ileal conduit or orthotopic neobladder does not seem to impact the rates of perioperative infectious, wound and bowel complications. Larger series with multiple surgeons are necessary to confirm these findings.


Circulation-cardiovascular Imaging | 2016

Prognosis of Myocardial Damage in Sarcoidosis Patients With Preserved Left Ventricular Ejection Fraction: Risk Stratification Using Cardiovascular Magnetic Resonance.

Gillian Murtagh; Luke J. Laffin; John F. Beshai; Francesco Maffessanti; Catherine A. Bonham; Amit V. Patel; Zoe Yu; Karima Addetia; Victor Mor-Avi; D. Kyle Hogarth; Nadera J. Sweiss; Roberto M. Lang; Amit R. Patel

Background—Cardiac sarcoidosis is associated with an increased risk of heart failure and sudden death, but its risk in patients with preserved left ventricular ejection fraction is unknown. Using cardiovascular magnetic resonance in patients with extracardiac sarcoidosis and preserved left ventricular ejection fraction, we sought to (1) determine the prevalence of cardiac sarcoidosis or associated myocardial damage, defined by the presence of late gadolinium enhancement (LGE), (2) quantify their risk of death/ventricular tachycardia (VT), and (3) identify imaging-based covariates that predict who is at greatest risk of death/VT. Methods and Results—Parameters of left and right ventricular function and LGE burden were measured in 205 patients with left ventricular ejection fraction >50% and extracardiac sarcoidosis who underwent cardiovascular magnetic resonance for LGE evaluation. The association between covariates and death/VT in the entire group and within the LGE+ group was determined using Cox proportional hazard models and time-dependent receiver–operator curves analysis. Forty-one of 205 patients (20%) had LGE; 12 of 205 (6%) died or had VT during follow-up; of these, 10 (83%) were in the LGE+ group. In the LGE+ group (1) the rate of death/VT per year was >20× higher than LGE− (4.9 versus 0.2%, P<0.01); (2) death/VT were associated with a greater burden of LGE (14±11 versus 5±5%, P<0.01) and right ventricular dysfunction (right ventricular EF 45±12 versus 53±28%, P=0.04). LGE burden was the best predictor of death/VT (area under the receiver-operating characteristics curve, 0.80); for every 1% increase of LGE burden, the hazard of death/VT increased by 8%. Conclusions—Sarcoidosis patients with LGE are at significant risk for death/VT, even with preserved left ventricular ejection fraction. Increased LGE burden and right ventricular dysfunction can identify LGE+ patients at highest risk of death/VT.

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