摘要:

BackgroundPenetrating transmural arteries with a diameter of <500 μm are considered to be a critical vascular component that causes a transmural variation of myocardial blood flow under various pathophysiological conditions. However, the conventional coronary angiographic system is not oriented to the visualization of such small arteries as these.Methods and ResultsWe magnified and monochromatized the inherently narrow beam (3 mm along the vertical direction) of synchrotron radiation by using an asymmetrically cut silicon crystal with 311 reflecting planes to obtain a monochromatic x-ray with relatively large beam size (60×25 mm) and with an energy of just above (+130 eV) the K-absorption edge of the contrast materials (33.17 and 37.41 keV for iodine and barium, respectively). We irradiated dogs or excised hearts with the monochromatic x-ray and obtained coronary angiograms using an image intensifier and video system with a spatial resolution of 170 μm. In the anesthetized dog experiments, we visualized the transmural penetrating arteries (5 to 15 μm in length) arising every 4 to 7 mm from the epicardial branch. Visualization of these arteries filled with heavy element- loaded microspheres (15 gm in diameter) in the excised- heart experiments, in which the monochromatic x-ray was irradiated to the hearts through a 10- to 20-cm acrylic plate, indicated that this system could be used for human patients, in whom body absorption of x-ray is substantial.ConclusionsCoronary angiogram by means of monochromatic x-ray is useful for a precise evaluation of coronary circulation, both in clinical settings and in physiological animal experiments.

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

AbstractTriaging patients suspected of myocardial infarction is performed primarily in the coronary care unit, with infarction determined within 12 to 24 hours, and only about 20% are subsequently shown to have myocardial infarction. Plasma MB CK is not elevated until 8 to 10 hours after onset, and the ECG is unreliable; thus, the need has arisen for a new “diagnostic mind-set.” The need is threefold: (1) more effective triaging in the emergency room to prevent unnecessary use of hospital beds, particularly those in the intensive care units, (2) to administer thrombolytic therapy in the early hours, and (3) earlier detection of coronary reocclusion and reinfarction. Diagnostic imaging techniques such as pyrophosphate, thallium-201 technetium sestamibi, or positron emitting agents lack the necessary early diagnostic specificity, but echocardiography has potential although its specificity is limited. Plasma CK isoforms provide diagnostic sensitivity and specificity of 96% and 94%, respectively, within the initial 4 to 6 hours of onset and can be assayed within minutes. In a prospective study of 1100 patients suspected of infarction, with conventional MB CK, 22% of the patients admitted to the coronary care unit would have had infarction, whereas using the CK isoforms, 75% had infarction and about 50% were discharged home. A scenario for the future might be to initiate thrombolytic therapy outside the hospital (eg, recombinant tissue-type plasminogen activator [r-TPA] 20 mg bolus) and upon arrival, confirm or exclude infarction by the MB CK isoform which can be performed in the emergency room in 20 minutes to determine whether thrombolytic therapy and heparin should be continued.

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundRotational atherectomy using the Rotablator has recently become available to treat coronary stenoses. This study was performed to determine the relation of patient characteristics, stenosis morphology, and operator technique procedural outcome to gain insight into which patients might be best treated with this device.Methods and ResultsFour hundred stenoses from 316 patients randomly selected from the initial Rotablator experience at three major referral institutions were analyzed. Angiographic data were assessed at a central angiographic laboratory using standardized morphological criteria and caliper measurement. Patients were somewhat more elderly than most percutaneous transluminal coronary angioplasty (PTCA)-treated groups (mean age, 64±11 years), 74% were men, and the lesions treated were often complex (modified American College of Cardiology/American Heart Association lesion type A, 24%; Bi, 40%; B2, 30%; and C, 6%). Elective adjunctive PTCA was used for 82% of stenoses treated. Procedural success was achieved in 89.8% of stenoses (93.5% if results with creatine kinase two to three times normal are not counted as failures), and major ischemic complications (death, 0.3%; non-Q-wave myocardial infarction, 5.7%; Q-wave myocardial infarction, 2.2%; or emergency bypass surgery, 0.9%) occurred in 8.9% of patients. Complications were due to epicardial coronary obstruction in 3.8% of patients and to delayed coronary runoff (“slow reflow”) in 5.1% of patients. Procedural failure was correlated independently with outflow obstruction (success rate, 64%; odds ratio for failure, 5.4; multivariateP= .002), lesion irregularity (76%; odds ratio, 3.3;P= .003), stenosis bend .600 (73%; odds ratio, 3.7;P= .03), and female sex (84%; odds ratio, 2.4;P= .03). Ischemic complications were correlated independently with lesion length (≥50% narrowing) ≥4 mm (complication rate, 12%; odds ratio, 3.6; multivariateP= .005), right coronary artery stenosis (13%; odds ratio, 2.4;P= .02), stenosis bend ≥60° (27%; odds ratio, 6.1;P= .03), and female sex (13%; odds ratio, 3.0;P= .04). Slow reflow was correlated with total burring duration (odds ratio, 1.005/s; multivariateP= .001), right coronary artery stenosis (incidence, 17%; odds ratio, 4.5;P= .009), and to a lesser extent with recent myocardial infarction in the treated territory (44%; odds ratio, 4.3;P= .08).ConclusionsThe procedural outcome of rotational atherectomy is highly correlated with stenosis morphology and location and sex of the patient. After stratification for these parameters, overall outcome with the Rotablator appears to be similar to that with balloon angioplasty and other competing techniques. Short-term outcome with specific subsets of patients may be superior with the Rotablator calcified stenoses), but this technique might best be avoided in some patients (those with irregular or possibly thrombuscontaining stenoses, highly angulated stenoses, and possible right coronary artery stenoses or those associated with impaired distal runoff caused by a recent myocardial infarction or manifest by a fixed thallium defect).

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID