Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Guy S. Mayeda is active.

Publication


Featured researches published by Guy S. Mayeda.


Journal of the American Heart Association | 2013

Testosterone and the Cardiovascular System: A Comprehensive Review of the Clinical Literature

Peyman Mesbah Oskui; William J. French; Michael J. Herring; Guy S. Mayeda; Steven Burstein; Robert A. Kloner

Recent data from the Massachusetts Male Aging Study (MMAS) have revealed an increasing incidence of hypogonadism within the aging US population. The Massachusetts Male Aging Study estimates indicate that ≈2.4 million men aged 40 to 69 suffer from hypogonadism in the United States.[1][1] The


International Journal of Clinical Practice | 2012

Emotional stressors trigger cardiovascular events

Bryan G. Schwartz; William J. French; Guy S. Mayeda; Steven Burstein; Christina Economides; A. K. Bhandari; D. S. Cannom; Robert A. Kloner

Aims:  To describe the relation between emotional stress and cardiovascular events, and review the literature on the cardiovascular effects of emotional stress, in order to describe the relation, the underlying pathophysiology, and potential therapeutic implications.


American Journal of Cardiology | 2012

Therapeutic hypothermia for acute myocardial infarction and cardiac arrest.

Bryan G. Schwartz; Robert A. Kloner; Joseph L. Thomas; Quang T. Bui; Guy S. Mayeda; Steven Burstein; Sharon L. Hale; Christina Economides; William J. French

This report focuses on cardioprotection and describes the advantages and disadvantages of various methods of inducing therapeutic hypothermia (TH) with regard to neuroprotection and cardioprotection for patients with cardiac arrest and ST-segment elevation myocardial infarction (STEMI). TH is recommended in cardiac arrest guidelines. For patients resuscitated after out-of-hospital cardiac arrest, improvements in survival and neurologic outcomes were observed with relatively slow induction of TH. More rapid induction of TH in patients with cardiac arrest might have a mild to modest incremental impact on neurologic outcomes. TH drastically reduces infarct size in animal models, but achievement of target temperature before reperfusion is essential. Rapid initiation of TH in patients with STEMI is challenging but attainable, and marked infarct size reductions are possible. To induce TH, a variety of devices have recently been developed that require additional study. Of particular interest is transcoronary induction of TH using a catheter or wire lumen, which enables hypothermic reperfusion in the absence of total-body hypothermia. At present, the main methods of inducing and maintaining TH are surface cooling, endovascular heat-exchange catheters, and intravenous infusion of cold fluids. Surface cooling or endovascular catheters may be sufficient for induction of TH in patients resuscitated after out-of-hospital cardiac arrest. For patients with STEMI, intravenous infusion of cold fluids achieves target temperature very rapidly but might worsen left ventricular function. More widespread use of TH would improve survival and quality of life for patients with out-of-hospital cardiac arrest; larger studies with more rapid induction of TH are needed in the STEMI population.


Catheterization and Cardiovascular Diagnosis | 1996

Reduced distal embolization with transluminal extraction atherectomy compared to balloon angioplasty for saphenous vein graft disease

Kazuo Misumi; Ray V. Matthews; Guo-Wen Sun; Guy S. Mayeda; Steven Burstein; Thomas Shook

Extraction atherectomy utilizes suction aspiration as an attempt to limit distal emboli during atherectomy. We sought to test the hypothesis that extraction atherectomy produces less distal embolization than balloon angioplasty when treating saphenous vein grafts. Among 163 consecutive, nonrandomized patients, 103 patients underwent transluminal extraction catheter (TEC) atherectomy with or without adjunctive balloon angioplasty, and 60 patients had conventional balloon angioplasty. Both groups showed comparably high procedural success rates (TEC 90.3%, angioplasty 83.3%, P = NS). TEC cases had a significantly lower incidence of angiographic distal embolization, compared with angioplasty (3.9% vs. 16.7%, P = 0.005). In cases with angiographic evidence of thrombus in the grafts, TEC maintained a significantly lower incidence of distal embolization than angioplasty (5.6% vs. 31.8%, P = 0.004). There were no statistical differences between the two groups regarding the incidence of other procedure-related complications, including death, myocardial infarction, or emergency coronary artery bypass grafting. TEC atherectomy appears to have a significantly lower incidence of distal embolization than balloon angioplasty when treating saphenous vein grafts, particularly in the presence of angiographically apparent thrombus.


Catheterization and Cardiovascular Interventions | 2009

Use of high-frequency vibrational energy in the treatment of peripheral chronic total occlusions.

Hazim Al-Ameri; Guy S. Mayeda; David M. Shavelle

Purpose: Peripheral chronic total occlusions (CTO) are challenging lesions to treat. The CROSSER system (FlowCardia, Sunnyvale, CA) uses high‐frequency low‐amplitude vibrations to break through the cap of the CTO and had been shown to be successful in coronary CTOs. This is a case series demonstrating the use of the CROSSER system with peripheral CTOs. Case Reports: Three patients with peripheral CTO of various lengths, locations, and complexities were treated with the CROSSER system. The device allowed placement of a guidewire across the area of occlusion, thus permitting further percutaneous intervention. The CROSSER system was effective with both ostial and distal lesions, tapered and abrupt lesion morphologies, and was used from both an ipsilateral (antegrade access) and contralateral approach. Conclusion: The CROSSER system is an additional device that may be used to treat peripheral CTOs.


Catheterization and Cardiovascular Interventions | 2009

Complication rate of diagnostic carotid angiography performed by interventional cardiologists

Hazim Al-Ameri; Mottsin L. Thomas; Anthony Yoon; Guy S. Mayeda; Steven Burstein; Robert A. Kloner; David M. Shavelle

Objective: The aim of this study was to evaluate the complication rate of diagnostic carotid angiography performed by interventional cardiologists and compare it to previously published data. Background: Percutaneous treatment for carotid artery stenosis is increasingly being performed. Previously published data describes the complication rate of diagnostic carotid angiography performed by radiologists and vascular surgeons, yet the information regarding interventional cardiologists is sparse. Currently in the United States, interventional cardiologists perform a great deal of diagnostic carotid angiograms. Methods: A retrospective analysis was done on 333 patients who underwent diagnostic carotid angiography at a single medical center from January 2000 to February 2007. Medical records were reviewed for cardiovascular risk factors, indications for the procedure, angiography technique and in‐hospital complications. Complications were categorized as neurological and non‐neurological. Neurological complications were further grouped into transient (<7 days) or permanent. Non‐neurological complications were grouped into major (requiring additional treatment) or minor. Results: Three hundred and thirty‐three patients underwent 347 diagnostic carotid angiograms. Twelve (3.5%) complications occurred in 12 patients. No cerebral vascular accidents occurred and only one (0.3%) transient ischemic attack occurred. Two patients required blood transfusions following the index procedure yielding a major non‐neurological complication rate of 0.6%. Review of the literature revealed a transient neurological complication rate from 0 to 2.4% and a major non‐neurological complication rate of 0.26–4.3%. Conclusions: Neurological and non‐neurological complication rates for carotid angiograms performed by interventional cardiologists are low and compare well with the literature. Interventional cardiologists can safely perform diagnostic carotid angiography with low complication rates.


Catheterization and Cardiovascular Interventions | 2006

Rescue Percutaneous Coronary Intervention for Failed Thrombolysis

David M. Shavelle; Ali Salami; Murrad Abdelkarim; William J. French; Thomas Shook; Guy S. Mayeda; Steven Burstein; Ray V. Matthews

Background: Previous studies of rescue percutaneous coronary intervention (PCI) for failed thrombolysis yielded conflicting results. In the current era of newer thrombolytic agents, coronary stents, glycoprotein IIb/IIIa inhibitors, and aggressive hemodynamic support, the outcome of this high‐risk patient group has not been characterized. Methods: From January 2000 to October 2004, 214 consecutive patients were transferred and underwent emergent coronary angiography following failed thrombolysis. One hundred and fifty five (72%) underwent immediate PCI, 23 (11%) underwent delayed PCI, and 36 (17%) received surgical revascularization or medical therapy. Medical records and angiograms for the entire PCI cohort (n= 178) were reviewed for in‐hospital events including bleeding complications, stroke, recurrent ischemia or myocardial infarction (MI), target vessel revascularization (TVR), and death. Results: Time from symptom onset to thrombolysis (mean ± standard deviation) was 5.6 ± 11.9 hr, and time from thrombolysis to angiography was 7.0 ± 5.5 hr. The study cohort was critically ill, with 9.6% experiencing cardiac arrest, 21% in cardiogenic shock, and 12% intubated prior to transfer. Coronary stents were placed in 88%, Rheolytic thrombectomy was used in 21%, an intraaortic balloon pump was placed in 17%, and a glycoprotein IIb/IIIa inhibitor was administered in 92%. Patients receiving delayed PCI had higher TIMI 3 flow grade at initial angiography than those receiving immediate PCI (83% vs. 34%, respectively, P < 0.0001). Angiographic success was 90% for the entire PCI cohort, 89% for the immediate PCI group, and 100% for the delayed PCI group. Clinical success (angiographic success and freedom from major adverse cardiac events) was 85% for the entire PCI cohort, 83% for the immediate PCI group, and 100% for the delayed PCI group. Severe and moderate bleeding complications occurred in 7.3%, stroke in 1.7%, recurrent ischemia or MI in 7.3%, and TVR in 3.4%. Overall, in‐hospital mortality for the entire PCI cohort was 3.4%. Conclusions: This observational, consecutive, real‐world study of contemporary rescue PCI for failed thrombolysis shows a high use of coronary stents, Rheolytic thrombectomy, glycoprotein IIb/IIIa inhibitors, and intraaortic balloon pump placement. Angiographic and clinical success was high with low bleeding complications and low in‐hospital mortality, suggesting that prospective, randomized trials using contemporary interventional therapy for rescue PCI be considered.


Journal of Endovascular Therapy | 2011

Study to Determine the CLinical Significance of HEmolysis During Orbital AtheRectomy (CLEAR Study)

Cezar S. Staniloae; Ravikiran Korabathina; Thomas A. Lane; Raymond Dattilo; Kevin J. Church; Kanika Mody; Guy S. Mayeda

Purpose: To evaluate the incidence of clinically evident hemolysis associated with orbital atherectomy used to treat severe peripheral artery disease. Methods: The observational CLEAR study enrolled 31 subjects (16 men; mean age 71±10 years, range 44–92) with claudication (58.1%) or critical limb ischemia (38.7%) who underwent orbital atherectomy with the Diamondback 360 system at 4 US centers. The 42 lesions in 31 limbs were located in the superficial femoral (n = 19, 45.2%), popliteal (n=8, 19.0%), and tibial arteries (n = 15, 35.8%). The majority of lesions (34, 81.0%) were de novo; moderate or severe calcification was identified in 90.5% of cases. Lesion and procedural parameters were analyzed at a core laboratory. Blood samples were collected during and post procedure and analyzed for markers of hemolysis. The primary endpoint was the occurrence of clinically significant hemolysis. The secondary endpoints included the occurrence of any clinical symptoms/signs potentially related to hemolysis. Statistical analysis was performed to identify predictors for hemolysis. Results: Laboratory evidence of hemolysis was seen in 11 (35.5%) subjects. No one met the clinical event criteria, and so the primary endpoint of the study was not reached. The secondary endpoints were hypertensive crisis (1, 3.2%) and transient hemoglobinuria (3, 9.7%). Lower glomerular filtration rates, calcified plaque, long atherectomy runs, and solid crown selection were independent predictors of hemolysis. Conclusion: There was no clinically significant hemolysis after orbital atherectomy. The results of this study will enable users to predict conditions that predispose to high levels of red cell hemolysis following orbital atherectomy and to take appropriate measures to limit its occurrence.


Hospital Practice | 2010

When and why do heart attacks occur? Cardiovascular triggers and their potential role.

Bryan G. Schwartz; Guy S. Mayeda; Steven Burstein; Christina Economides; Robert A. Kloner

Abstract Coronary heart disease affects 7.6% of the population in the United States, where > 900 000 myocardial infarctions (MIs) occur annually. Approximately half of all MIs have an identifiable clinical trigger. Myocardial ischemia, MI, sudden cardiac death, and thrombotic stroke each occur with circadian variation and peak after waking in the morning. In addition, physical exertion and mental stress are common precipitants of MI. Waking in the morning, physical exertion, and mental stress influence a number of physiologic parameters, including blood pressure, heart rate, plasma epinephrine levels, coronary blood flow, platelet aggregability, and endothelial function. Upregulation of sympathetic output and catecholamines increase myocardial oxygen demand and can decrease myocardial oxygen supply and promote thrombosis. Ischemia ensues when myocardial oxygen demand exceeds supply. Increases in blood pressure and ventricular contractility increase intravascular shear stress and may cause vulnerable atherosclerotic plaques to rupture, forming a nidus for thrombosis that can precipitate MI. Numerous clinical triggers of MI have been identified, including blizzards, the Christmas and New Years holidays, experiencing an earthquake, the threat of violence, job strain, Mondays for the working population, sexual activity, overeating, smoking cigarettes, smoking marijuana, using cocaine, and particulate air pollution. Avoiding clinical triggers or participating in therapies that prevent clinical triggers from precipitating cardiac events could potentially postpone clinical events by several years and improve cardiovascular morbidity and mortality. Direct or indirect evidence suggests that the risk of triggered MIs is reduced with β-blockers, aspirin, statins, stress management, and transcendental meditation.


Catheterization and Cardiovascular Interventions | 2002

Intravascular ultrasound diagnosis of a venous obstruction not visualized by conventional venography: A case report

Eugene Byun; Guy S. Mayeda

Superior vena cava (SVC) syndrome from extrinsic compression has been classically linked with underlying malignancy, most commonly pulmonary malignancy, while benign SVC syndrome has been less common [1]. SVC syndrome from ascending aorta pathologies has also been described [2–8]. Isolated case reports of left inominate vein (LIV) extrinsic compression by the thoracic aorta (unilateral SVC syndrome) have been even more rare [9,10]. We report a case in which a patient presents with subacute unilateral left upper extremity venous hypertension manifest as isolated left arm edema 6 weeks following surgical repair of an ascending aortic dissection and 1 week after placement of a left upper arm AV dialysis graft. He was eventually diagnosed with unilateral SVC syndrome, but the unique modalities used to confirm the diagnosis are described.

Collaboration


Dive into the Guy S. Mayeda's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Robert A. Kloner

Huntington Medical Research Institutes

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

David M. Shavelle

University of Southern California

View shared research outputs
Top Co-Authors

Avatar

Ray V. Matthews

University of Southern California

View shared research outputs
Top Co-Authors

Avatar

Thomas Shook

Brigham and Women's Hospital

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Kazuo Misumi

Good Samaritan Hospital

View shared research outputs
Researchain Logo
Decentralizing Knowledge