PubMed Health⌕ Search

Biomedical subjects

Mehmet Oz

Publications and source records attributed to Mehmet Oz.

16 recordsLinked to original sources
PubMed2006

Transcatheter aortic valve replacement in patients with critical aortic stenosis: rationale, device descriptions, early clinical experiences, and perspectives.

The development of lesser invasive transcatheter techniques for aortic valve replacement (AVR) to treat high surgical risk patients with severe aortic stenosis (AS) has engendered controversy among traditional cardiovascular therapists. Presently, there are two catheter-based treatment systems (the Cribier-Edwards Aortic Bioprosthesis and the CoreValve Revalving System) utilizing either a balloon-expandable or a self-expanding stent (or cage) platform which unfolds a pericardial tissue valve within the displaced diseased aortic valve. After ex vivo durability testing and animal studies, several clinical registries with these transcatheter AVR systems in almost 300 patients worldwide have demonstrated the following: (1) good acute hemodynamic performance with reduction in mean aortic valve gradients to <10 mm Hg; (2) frequent para-valvular regurgitation, which has improved with self-expanding devices and the use of larger (26 mm) valve sizes; (3) acceptable periprocedural (30-day) mortality (<10%) with the newest generation devices and improved operator techniques. Enlightened interdisciplinary treatment teams incorporating surgeons, interventionalists, and medical therapists as well as rigorously conducted randomized clinical trials will be required to determine if these innovative transcatheter AVR approaches will represent a viable therapy for high-risk patients with severe AS in the future.

Aortic Valve Insufficiency↗
PubMed2006

Mechanisms of atrial tachyarrhythmias following surgical atrial fibrillation ablation.

INTRODUCTION: Typical and atypical atrial flutters (AFLs) and atrial tachycardias (ATs) have been reported in patients with prior surgical atrial fibrillation ablation. The underlying mechanisms for this group of atrial tachyarrhythmias have not been well characterized and the efficacy of catheter ablation in their treatment is unknown. METHODS AND RESULTS: Twenty patients (6 females) with a surface ECG diagnosis of AFL or AT following surgical atrial fibrillation ablation underwent 26 electrophysiology studies. Patients manifesting sustained, organized, and beat-by-beat reproducible atrial electrical activity underwent complete right and left atrial catheter mapping and catheter ablation. One patient had no inducible tachyarrhythmia, while 5 patients had nonmappable arrhythmias. Nineteen of the 31 potentially mappable atrial tachyarrhythmias were completely characterized in 14 patients. The underlying mechanisms were macro-reentrant left AFL (n = 9), focal left AT (n = 3), typical right AFL (n = 6), and atypical right AFL (n = 1). Of the 19 completely characterized atrial arrhythmias, catheter ablation was performed for 18, and the procedure was successful for 13 of these. After a mean follow-up of 15 +/- 10 months, 15 of 20 patients (75%) were in sinus rhythm including 10 of 13 patients (77%) with AT/flutter ablation. Ten patients, including 6 following ablation, were maintaining sinus rhythm without antiarrhythmic medications. CONCLUSIONS: Patients with an ECG diagnosis of AFL or AT following surgical atrial fibrillation ablation may have multiple tachycardia mechanisms with the right or left atrium as the site of origin. Many of these rhythms may resolve with further maturation of surgical atrial fibrillation ablation (SAFA) lesions or be treatable with antiarrhythmic medication. However, persistent tachyarrhythmias can often be treated successfully with catheter mapping and ablation.

Atrial Fibrillation↗
PubMed2003

Use of rapamycin slows progression of cardiac transplantation vasculopathy.

BACKGROUND: Cardiac transplantation vasculopathy is the leading cause of late death in heart transplantation recipients. Rapamycin is an immunosuppressant drug with potent antiproliferative and antimigratory effects. We investigated whether rapamycin could prevent progression of graft vasculopathy in 46 patients (age, 54+/-10 years; 4.3+/-2.3 years after transplantation) with severe disease. METHODS AND RESULTS: At annual cardiac catheterization, patients were randomly assigned to treatment with rapamycin (n=22) versus continued current immunosuppression (n=24). Clinical characteristics including recipient age and sex, underlying cause of congestive heart failure, donor age and sex, and ischemic time were recorded. Cardiac catheterization was graded with the use of a semiquantitative scale and repeated annually. Clinically significant adverse events were defined as death, need for angioplasty or bypass surgery, myocardial infarction, and a >25% worsening of the catheterization score. These events were monitored as primary study end points. Anti-HLA class I and II antibody production and lymphocyte growth assays were measured with each biopsy. Patients selected for rapamycin had azathioprine or mycophenolate mofetil discontinued and were given rapamycin. Outcomes were compared by means of log-rank analysis. There were no significant differences in baseline characteristics. Duration of follow-up was comparable (rapamycin, 689+/-261; control, 630+/-207 days; NS). In the rapamycin group, 3 patients reached primary end points versus 14 patients in the control group (P<0.001). There was no difference in baseline or subsequent anti-HLA class I or II antibody production. CONCLUSIONS: In this patient cohort with cardiac vasculopathy, treatment with rapamycin slowed disease progression probably by its antiproliferative and antimigratory effects.

Arterial Occlusive Diseases↗
PubMed2003

Insertion of a left ventricular assist device in patients without thorough transplant evaluations: a worthwhile risk?

OBJECTIVES: Patients in acute cardiogenic shock may require placement of left ventricular assist devices before undergoing standard pretransplant evaluations. This practice raises ethical and logistic concerns and has led us to investigate the short- and long-term outcomes for this patient population. Methods and results We examined our adult bridge-to-transplant left ventricular assist device population over a 6-year period to characterize those patients with acute cardiogenic shock who received left ventricular assist devices on an emergency basis (ie, placement of a device within 24 hours of being listed for cardiac transplantation). Outcomes before and after transplant were compared with those of candidates with nonemergency evaluations by Kaplan-Meier survival curves and the Fisher exact test where appropriate. Of the 115 patients who required left ventricular assist device support, 73 (63%) patients required emergency placement; 70% of these patients survived to transplant compared with 83% of those with nonurgent device implantation (not statistically significant). Posttransplant survival curves were similar for patients with emergency device placement and those with nonurgent placement (not statistically significant). Twenty-two patients having emergency device placement did not undergo heart transplantation because of multisystem organ failure (14), device support withdrawal from irreversible neurologic injury (4), device or technical problems (2), and left ventricular assist device explant due to myocardial recovery (2). CONCLUSIONS: At our institution, the majority of left ventricular assist devices are placed on an emergency basis. Few of these patients require discontinuation of device support due to undetected conditions during abbreviated preoperative evaluation. Survival before and after transplant is comparable with those of patients who undergo nonurgent left ventricular assist device placement or medical therapy.

Adult↗
PubMed2003

Assessment of myocardial recovery in a patient with acute myocarditis supported with a left ventricular assist device: a case report.

Acute myocarditis may present with profound hemodynamic compromise; however, spontaneous resolution of the inflammatory process may occur in up to half of such patients. In patients with fulminant myocarditis, mechanical circulatory support may serve as a bridge to myocardial recovery. In this report we describe a 35-year-old man with acute myocarditis who required left ventricular assist device support as a bridge to recovery, and suggest a method for determining the suitability and timing of device explantation. A combination of echocardiography, right heart catheterization, exercise testing and serial endomyocardial biopsies was used to determine the resolution of myocarditis, recovery of myocardial function and timing for device explantation. Successful device explantation was performed after 37 days of device support. Further study is required to assess the role of ventricular assist devices in combination with immunosuppressive therapy in the management of fulminant myocarditis.

Acute Disease↗
PubMed2002

Intravenous pulse administration of cyclophosphamide is an effective and safe treatment for sensitized cardiac allograft recipients.

BACKGROUND: The proportion of cardiac transplant recipients with preexisting sensitization to HLA alloantigens has been increasing. Sensitization prolongs duration to obtaining a donor and predicts poorer long-term allograft survival because of increased risk of cellular rejections. We investigated the effect of cyclophosphamide pulse therapy in sensitized cardiac allograft recipients. METHODS AND RESULTS: Pretransplant and posttransplant outcomes were compared between 88 cardiac allograft recipients at risk for sensitization and 26 sensitized recipients treated with intravenous cyclophosphamide pulse therapy together with intravenous immune globulin before transplant and as part of a cyclosporine-based triple immunosuppressive regimen after transplant. Preformed IgG anti-HLA antibodies predicted longer duration to transplantation, earlier cellular rejection, and 2.7-fold higher cumulative rejection frequency (P=0.002). Before transplant, cyclophosphamide reduced waiting time and mortality to levels in nonsensitized patients. After transplant, cyclophosphamide prevented induction of IgG anti-HLA class II antibodies and interleukin-2 receptor--positive T-cell outgrowth from biopsy sites (both P<0.01), prolonged the rejection-free interval (P=0.009), and reduced cumulative rejections to levels in nonsensitized patients (P=0.003). By multivariable analysis, the risk of rejection was 3.7-fold higher in patients treated with mycophenolate mofetil than patients treated with cyclophosphamide (P=0.019). There were no differences in infectious or other significant complications. CONCLUSIONS: Immunosuppression incorporating intravenous cyclophosphamide before and after transplantation is safe and highly effective in sensitized cardiac transplant recipients. When used after transplantation as part of triple immunosuppression, cyclophosphamide is superior to mycophenolate mofetil in reducing rejection. The mechanism may involve prevention of diversification of the recipient immune response to donor HLA class II molecules.

Adult↗
PubMed2002

B-cell activation and allosensitization after left ventricular assist device implantation is due to T-cell activation and CD40 ligand expression.

Left ventricular assist device (LVAD) implantation is frequently complicated by B-cell activation and allosensitization, posing a significant risk to successful transplant outcome. This study investigated whether B-cell hyperreactivity and alloantibody production in LVAD recipients involves T-cell dependent pathways. T-cell calcium flux and nuclear translocation of NFATc were used to determine states of T-cell activation. Flow cytometry was used to assess human T- and B-cell activation after culture with LVAD-derived biomaterial particles. Sera from LVAD recipients and controls were tested for the presence of anti-HLA antibodies, and for soluble CD40 ligand. LVAD-derived biomaterial induced rapid and sustained calcium flux into normal T cells, resulting in calcineurin-dependent nuclear translocation of NFATc. This resulted in increased T-cell expression of CD40 ligand and subsequent B-cell activation, which was reduced by inhibitors of T-cell activation (CsA or anti-CD25 mAb) or by anti-CD40 ligand mAb. LVAD recipients demonstrated higher frequencies of anti-HLA antibodies and serum levels of soluble CD40 ligand compared with heart failure controls. The results indicate that exposure of human mononuclear cells to LVAD-derived biomaterial leads to T-cell dependent B-cell activation via CD40--CD40 ligand interaction, and suggest that treatment with calcineurin inhibitors or monoclonal antibodies against either CD25 or CD40 ligand could be effective at preventing B-cell hyperreactivity and allosensitization after LVAD implantation.

B-Lymphocytes↗
PubMed2002

Partial loading of the left ventricle during mechanical assist device support is associated with improved myocardial function, blood flow and metabolism and increased exercise capacity.

BACKGROUND: Myocardial recovery has been observed after placement of left ventricular assist devices in some patients awaiting cardiac transplantation. Left ventricular assist devices provide profound volume and pressure unloading while restoring systemic blood flow. However, the optimal degree of left ventricular unloading during left ventricular assist device support is unknown. The purpose of this study was to assess the effect of the degree of left ventricular decompression, during left ventricular assist device support, on myocardial function and exercise capacity. METHODS: Twenty patients with a left ventricular assist device performed cardiopulmonary exercise testing with simultaneous echocardiographic and hemodynamic measurements during full, and then partial, device support. Eleven patients underwent positron emission tomographic scanning for measurement of myocardial blood flow and oxygen consumption. RESULTS: Patients were divided into two groups based on the degree of left ventricular decompression as assessed by echocardiographic measurements. Patients with partially decompressed ventricles (n = 13, LVEDD = 4.8 +/- 1.0 cm) as compared to those with fully decompressed ventricles (n = 10, LVEDD = 3.0 +/- 0.3 cm) demonstrated significant improvements in: peak oxygen consumption (16.8 +/- 4.3 versus 12.8 +/- 3.0 ml/kg.min), native left ventricular index during exercise (2.5 +/- 1.4 versus 0.8 +/- 0.8 liters/min.m(2)); ability to exercise with the device weaned (10 of 13 versus 1 of 10 patients); resting myocardial blood flow (0.55 +/- 0.11 versus 0.21 +/- 0.13 ml/g.min); and myocardial oxygen consumption (0.04 +/- 0.01 versus 0.02 +/- 0.001 min-1) (all p < 0.05). CONCLUSIONS: These results suggest that partial loading of the left ventricle during left ventricular assist device support may be beneficial. Further study of optimal ventricular decompression during device support is needed, as this may be important in improving myocardial recovery.

Adult↗
PubMed2002

Assessment of synchrony relationships between the native left ventricle and the HeartMate left ventricular assist device.

BACKGROUND: It has been suggested that the cardiac cycle becomes synchronized with the LVAD. Synchronization between the left ventricle and the LVAD may be important for ventricular unloading and coronary flow. In this study, we assessed the synchrony between the cardiac and LVAD cycles. METHODS: We studied 24 patients with HeartMate LVAD support. Native heart rate from an electrocardiogram and LVAD rate were measured at rest and peak exercise. Three patients underwent simultaneous invasive pressure measurement from the left ventricle and the aorta, and 3 patients underwent simultaneous recording of electrocardiogram and LVAD electrical signal. RESULTS: Resting heart rate was significantly higher than LVAD rate (96 +/- 17 vs 66 +/- 15 beats [b]/min, p < 0.0001), with no correlation between the 2 (r = 0.25). Peak heart rate was significantly higher than LVAD rate (142 +/- 16 vs 102 +/- 14 b/min, p < 0.0001), with no correlation observed (r = 0.31). Electrical signal recording confirmed the absence of cardiac-LVAD synchrony. Pressure measurements revealed a cyclical intraventricular pressure variation, determined by the relationship between the cardiac and LVAD cycles. Intraventricular pressure was lowest when left ventricular systole occurred during pump filling and highest when left ventricular systole occurred during pump ejection. CONCLUSIONS: The cardiac and LVAD cycles are not in synchrony at rest or at peak exercise. However, a cyclical variation in left ventricular pressure exists, dependent upon the phasic relationship of the cardiac-LVAD cycles, which significantly effects ventricular loading. Better understanding of this relationship may be important in developing assist devices for optimal left ventricular unloading and improvement of myocardial recovery.

Adult↗
PubMedDate not supplied

Music, imagery, touch, and prayer as adjuncts to interventional cardiac care: the Monitoring and Actualisation of Noetic Trainings (MANTRA) II randomised study.

BACKGROUND: Data from a pilot study suggested that noetic therapies-healing practices that are not mediated by tangible elements-can reduce preprocedural distress and might affect outcomes in patients undergoing percutaneous coronary intervention. We undertook a multicentre, prospective trial of two such practices: intercessory prayer and music, imagery, and touch (MIT) therapy. METHODS: 748 patients undergoing percutaneous coronary intervention or elective catheterisation in nine USA centres were assigned in a 2x2 factorial randomisation either off-site prayer by established congregations of various religions or no off-site prayer (double-blinded) and MIT therapy or none (unmasked). The primary endpoint was combined in-hospital major adverse cardiovascular events and 6-month readmission or death. Prespecified secondary endpoints were 6-month major adverse cardiovascular events, 6 month death or readmission, and 6-month mortality. FINDINGS: 371 patients were assigned prayer and 377 no prayer; 374 were assigned MIT therapy and 374 no MIT therapy. The factorial distribution was: standard care only, 192; prayer only, 182; MIT therapy only, 185; and both prayer and MIT therapy, 189. No significant difference was found for the primary composite endpoint in any treatment comparison. Mortality at 6 months was lower with MIT therapy than with no MIT therapy (hazard ratio 0.35 (95% CI 0.15-0.82, p=0.016). INTERPRETATION: Neither masked prayer nor MIT therapy significantly improved clinical outcome after elective catheterisation or percutaneous coronary intervention.

Aged↗
PubMedDate not supplied

Emerging role of integrative medicine in cardiovascular disease.

Our evolution toward a more integrative approach toward healing will accelerate if we can alter the different perspectives that patients and physicians bring to their relationship. This article reviews lessons that have been acquired using alternative approaches to facilitate the recovery of patients undergoing invasive procedures. After identifying that most of our patients use alternative therapies but prefer not to discuss these therapies with their surgeons, we began to routinely refer our patients to a coordinator trained in this field. The resulting integrative medicine program offers massage, yoga, audiotapes, and additional customized treatments. The coexisting research laboratory designs and conducts well-organized research endeavors evaluating the efficacy of therapies being offered. By mixing clinical practice with conventional research, we seek to emulate the successful formula used in allopathic medicine.

Cardiovascular Diseases↗