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(1/926) The US Food and Drug Administration investigational device exemptions (IDE) and clinical investigation of cardiovascular devices: information for the investigator.

The conduct of a clinical investigation of a medical device to determine the safety and effectiveness of the device is covered by the investigational device exemptions (IDE) regulation. The purpose of IDE regulation is "to encourage, to the extent consistent with the protection of public health and safety and with ethical standards, the discovery and development of useful devices intended for human use, and to that end to maintain optimum freedom for scientific investigators in their pursuit of this purpose" (Federal Food, Drug, and Cosmetic Act). Conducting a clinical investigation may require an approved IDE application. The US Food and Drug Administration encourages early interaction with the agency through the pre-IDE process during the development of a device or technology and during the preparation of an IDE application. This facilitates approval of the IDE application and progression into the clinical investigation. This paper reviews the terminology and applicability of the IDE regulation and the type of study that requires an IDE application to the Food and Drug Administration. The pre-IDE process and the development of an IDE application for a significant risk study of a cardiovascular device are discussed.  (+info)

(2/926) Evaluation of technician supervised treadmill exercise testing in a cardiac chest pain clinic.

OBJECTIVE: To determine the efficacy and safety of trained cardiac technicians independently performing treadmill exercise stress tests as part of the assessment of patients with suspected angina pectoris. DESIGN: Retrospective comparison of 250 exercise tests performed by cardiac technicians and 225 tests performed by experienced cardiology clinical assistants (general practitioners who perform regular NHS cardiology duties), and consultant cardiologists over the same time period. SETTING: Regional cardiac centre with a dedicated cardiac chest pain clinic. PATIENTS: All patients were referred by their general practitioners with a history of recent onset of chest pain, which was suspected to be angina pectoris. OUTCOME MEASURES: Peak workload achieved, symptoms, indications for termination, complications. RESULTS: The diagnostic yield of technician supervised tests (percentage positive or negative) was similar to that of medically supervised tests (76% v 69%, NS). The average peak workload achieved by patients was less by 1.2 mets (p < 0.005). This was probably due to more tests being terminated earlier due to chest pain and ST segment depression in the technician group compared with doctors (10% and 16% v 5% and 11% respectively, p = 0.06 and 0.07). One patient in the technician supervised group developed a supraventricular tachycardia during the recovery phase of the exercise test. CONCLUSIONS: Technician supervised stress testing is associated with a high diagnostic rate and low complication rate in patients with suspected ischaemic heart disease. Its efficacy is comparable to tests supervised by experienced doctors and its use should be encouraged.  (+info)

(3/926) Development of a heart failure center: a medical center and cardiology practice join forces to improve care and reduce costs .

Congestive heart failure (CHF) is a rapidly growing and expensive cardiovascular disorder. Conventional care for CHF is ineffective and results in a cycle of "crisis management" that includes repeated emergency department visits, hospitalizations, and physician visits. Recently, a number of outpatient coronary care centers that provide consistent, aggressive outpatient therapies and extensive patient education have emerged and are successfully breaking this cycle of dependence on hospital services. One such effort is the Heart Institute's Heart Failure Center, the result of a partnership between a private-practice cardiology group and our tertiary-care medical center. Our program includes not only patient education and outpatient infusions of inotropic agents, but an electronic linkage to the emergency department and home healthcare services. Preliminary data show that 16 months after the program was initiated, hospital admissions decreased by 30%, hospital days by 42% and average length of stay by 17%. An effective outpatient heart failure program can alleviate the economic burden of CHF and improve the quality of patient care.  (+info)

(4/926) The Framingham Offspring Study: a commentary. 1980.

Forty-three of 1,312 men aged 35 to 54 years in the Framingham Offspring Study had clinically recognized coronary heart disease at the initial examination. Twenty-six men in this group had previously had a myocardial infarction. Of 1,296 women in the same age range, only 11 had coronary disease and 3 a prior myocardial infarction. The prevalence of coronary heart disease in men was strongly associated with age, smoking, high density lipoprotein (HDL), low density lipoprotein (LDL) and total cholesterol using univariate analyses. When multivariate logistic regression analysis was used, age, smoking and HDL and LDL cholesterol retained their significant association with coronary heart disease. The total cholesterol/HDL cholesterol ratio was also strongly associated with coronary heart disease in the multivariate analysis. It is concluded that both HDL and LDL cholesterol are strongly and independently associated with the prevalence of coronary heart disease, whereas the level of very low density lipoprotein cholesterol makes no statistically significant independent contribution.  (+info)

(5/926) A view from the millennium: the practice of cardiology circa 1950 and thereafter.

The knowledge and treatment of cardiology as practiced circa 1950 is discussed as abstracted from authoritative textbooks of that time and other sources. Advances in treatment and diagnostic techniques since 1950 are presented. Dramatic changes in cardiology have come at the expense of bedside cardiology which needs to be balanced with the technology.  (+info)

(6/926) A prognostic computer model to individually predict post-procedural complications in interventional cardiology: the INTERVENT Project.

AIMS: The purpose of this part of the INTERVENT project was (1) to redefine and individually predict post-procedural complications associated with coronary interventions, including alternative/adjunctive techniques to PTCA and (2) to employ the prognostic INTERVENT computer model to clarify the structural relationship between (pre)-procedural risk factors and post-procedural outcome. METHODS AND RESULTS: In a multicentre study, 2500 data items of 455 consecutive patients (mean age: 61.1+/-8.3 years: 33-84 years) undergoing coronary interventions at three university centres were analysed. 80.4% of the patients were male, 16.7% had unstable angina, and 5.1%/10.1% acute/subacute myocardial infarction. There were multiple or multivessel stenoses in 16.0%, vessel bending >90 degrees in 14.5%, irregular vessel contours in 65.0%, moderate calcifications in 20.9%, moderate/severe vessel tortuosity in 53.2% and a diameter stenosis of 90%-99% in 44.4% of cases. The in-lab (out-of-lab) complications were: 0.4% (0.9%) death, 1.8% (0.2%) abrupt vessel closure with myocardial infarction and 5.5% (4.0) haemodynamic disorders. CONCLUSION: Computer algorithms derived from artificial intelligence were able to predict the individual risk of these post-procedural complications with an accuracy of >95% and to explain the structural relationship between risk factors and post-procedural complications. The most important prognostic factors were: heart failure (NYHA class), use of adjunctive/alternative techniques (rotablation, atherectomy, laser), acute coronary ischaemia, pre-existent cardiac medication, stenosis length, stenosis morphology (calcification), gender, age, amount of contrast agent and smoker status. Pre-medication with aspirin or other cardiac medication had a beneficial effect. Techniques, such as laser angioplasty or atherectomy were predictors for post-procedural complications. Single predictors alone were not able to describe the individual outcome completely.  (+info)

(7/926) Establishment of a simple and practical procedure applicable to therapeutic angiogenesis.

BACKGROUND: Therapeutic angiogenesis is thought to be beneficial for serious ischemic diseases. This investigation was designed to establish a simple and practical procedure applicable to therapeutic angiogenesis. METHODS AND RESULTS: When cultured skeletal muscle cells were electrically stimulated at a voltage that did not cause their contraction, vascular endothelial growth factor (VEGF) mRNA was augmented at an optimal-frequency stimulation. This increase of VEGF mRNA was derived primarily from transcriptional activation. Electrical stimulation increased the secretion of VEGF protein into the medium. This conditioned medium then augmented the growth of endothelial cells. The effect of electrical stimulation was further confirmed in a rat model of hindlimb ischemia. The tibialis anterior muscle in the ischemic limb was electrically stimulated. The frequency of stimulation was 50 Hz and strength was 0.1 V, which was far below the threshold for muscle contraction. After a 5-day stimulation, there was a significant increase in blood flow within the muscle. Immunohistochemical analysis revealed that VEGF protein was synthesized and capillary density was significantly increased in the stimulated muscle. Rats tolerated this procedure very well, and there was no muscle contraction, muscle injury, or restriction in movement. CONCLUSIONS: We propose this procedure as a simple and practical method of therapeutic angiogenesis.  (+info)

(8/926) The association between hospital volume and survival after acute myocardial infarction in elderly patients.

BACKGROUND: Patients with chest pain thought to be due to acute coronary ischemia are typically taken by ambulance to the nearest hospital. The potential benefit of field triage directly to a hospital that treats a large number of patients with myocardial infarction is unknown. METHODS: We conducted a retrospective cohort study of the relation between the number of Medicare patients with myocardial infarction that each hospital in the study treated (hospital volume) and long-term survival among 98,898 Medicare patients 65 years of age or older. We used proportional-hazards methods to adjust for clinical, demographic, and health-system-related variables, including the availability of invasive procedures, the specialty of the attending physician, and the area of residence of the patient (rural, urban, or metropolitan). RESULTS: The patients in the quartile admitted to hospitals with the lowest volume were 17 percent more likely to die within 30 days after admission than patients in the quartile admitted to hospitals with the highest volume (hazard ratio, 1.17; 95 percent confidence interval, 1.09 to 1.26; P<0.001), which resulted in 2.3 more deaths per 100 patients. The crude mortality rate at one year was 29.8 percent among the patients admitted to the lowest-volume hospitals, as compared with 27.0 percent among those admitted to the highest-volume hospitals. There was a continuous inverse dose-response relation between hospital volume and the risk of death. In an analysis of subgroups defined according to age, history of cardiac disease, Killip class of infarction, presence or absence of contraindications to thrombolytic therapy, and time from the onset of symptoms, survival at high-volume hospitals was consistently better than at low-volume hospitals. The availability of technology for angioplasty and bypass surgery was not independently associated with overall mortality. CONCLUSIONS: Patients with acute myocardial infarction who are admitted directly to hospitals that have more experience treating myocardial infarction, as reflected by their case volume, are more likely to survive than are patients admitted to low-volume hospitals.  (+info)