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Biomedical subjects

A E Raizner

Publications and source records attributed to A E Raizner.

108 records · Page 6Linked to original sources
PubMed1976

The clinical significance of exercise-induced ST-segment elevation.

The significance of exercise-induced ST-segment elevation remains unsettled. We reviewed the treadmill tests of 840 consecutive patients and exercise-induced ST-segment elevation was noted in 29 (3.5%). Only eight of these (28%) stopped because of angina. Anterior myocardial infarction (AMI) was found on the resting electrocardiogram in 25 (85%). Angiographic studies performed on 21 showed critical lesions of the left anterior descending (LAD) in 19 (90%) and left ventricular aneurysm in 18 (86%). When all the patiens who had AMI or critical LAD obstruction during the study period were reviewed, only 22% and 18% respectively showed exercise-induced ST-segment elevation, while 64% of the cases with left ventricular aneurysm displayed this phenomenon. Thus, exercise-induced ST elevation seems to reflect the presence of severe coronary artery disease most commonly with an associated left ventricular aneurysm and may relate more to the abnormal wall motion than to the myocardial ischemia per se.

Adult↗
PubMed1975

Coronary arterial spasm in classic angina pectoris.

A 47-year-old black male who presented with classical angina pectoris and positive exercise test developed spasm of the right coronary artery in the vicinity of an atherosclerotic lesion resulting in transient total occlusion of the vessel. It seemed unlikely that spasm was catheter induced in this case, and the vessel relaxed promptly following nitroglycerin administration. The occurrence of severe spasm in proximity to atherosclerotic narrowing of coronary artery may contribute to stable and unstable angina, myocardial infaction, and sudden death in patients with these conditions coexisting. The awareness of such a phenomenon is necessary to avoid serious errors in the interpretation of coronary angiograms.

Angina Pectoris↗
PubMed1975

The incidence and clinical implications of coronary artery spasm.

The total incidence of coronary artery spasm during coronary angiography has been reported to be between 0.26% and 0.93%. The rarity of this phenomenon has been invoked to minimize its clinical significance. Review of a one-year experience in our catheterization laboratory showed that coronary spasm occurred in eight of 274 coronary angiograms (2.93%). In three instances, spasm could not be ascribed to catheter tip irrigation, and was considered to be spontaneous. Since multiple factors during coronary arteriography might inhibit the occurrence of coronary spasm, it is believed that the incidence of spontaneous spasm may be higher than can be documented during angiography. Coronary spasm may have important clinical significance in various chest pain syndromes and greater methodical attention should be directed toward this phenomenon.

Adult↗
PubMedDate not supplied

Dose-response study of intracoronary beta-radiation with 32P in balloon- and stent-injured coronary arteries in swine.

PURPOSE: A dose-response study was performed in swine to investigate the vascular effects of 32P over a broad range of doses in order to define the therapeutic window of intracoronary radiotherapy (ICR) with 32P. METHODS AND MATERIALS: A total of 131 porcine arteries were subjected to balloon injury or stenting followed by 0-36 Gy of ICR from a centered 32P source wire to 1 mm beyond lumen surface or a sham ICR procedure. Animals were euthanized at 4 weeks, and vessels were harvested for histomorphometry. RESULTS: In the balloon-injured arteries, doses of 7 and 9 Gy did not impact restenosis. At doses of 14-36 Gy, neointima was markedly reduced, with mild dilatation at the highest dose, 36 Gy. In the stent-injured arteries, the lowest dose of 9 Gy failed to reduce neointimal growth, while 14-26 Gy showed the most favorable response. CONCLUSIONS: ICR with 32P features a broad therapeutic window. Doses of 14-26 Gy to 1 mm beyond lumen surface provided an optimal combination of efficacy and safety. Doses of 7 and 9 Gy were generally ineffective, suggesting a minimum threshold for ICR with 32P to effectively inhibit restenosis.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Clinical experience with a spiral balloon centering catheter for the delivery of intracoronary radiation therapy.

PURPOSE: To develop and evaluate an intravascular radiation delivery catheter that incorporates a centering mechanism and that allows side branch and distal artery perfusion. METHODS AND MATERIALS: The Galileo Centering Catheter (Guidant Vascular Interventions, Houston, TX) incorporates a rapid exchange tip design. A unique spiral balloon allows centering and facilitates perfusion to the distal artery and side branches. The catheter contains a dedicated dead-end lumen for source wire delivery to the lesion site. The treatment area is precisely defined by radiopaque markers. RESULTS: In three clinical trials to date, radiation (or placebo) was delivered successfully to 300 of 312 patients (96%). With balloon inflation, TIMI grade 2 or 3 flow was achieved in side branches in 82% and in the distal artery in 77% of patients. Despite treatment (dwell) times ranging from 87 to 948 s (mean = 250 s), only 8% of patients required fractionation of treatment. CONCLUSION: The Galileo Centering Catheter is a safe and highly effective method for delivering intracoronary radiation therapy. Its unique design provides centering of the source while allowing side branch and distal coronary perfusion during treatment. This catheter would facilitate intracoronary radiation therapy and allow uniform and reproducible dose delivery to the target in the artery wall.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

The mechanism of hypotension following angiography.

The hypotension observed following the intracardiac injection of contrast media is believed to be the result of myocardial depression, peripheral vasodilatation, or both. It is unclear which of these factors is primarily involved in different types of angiography. To assess this problem, Renografin-76 was injected into the aortic root of 15 anesthetized dogs (1 ml/kg) and into the left coronary artery (3-5 ml) in 18 dogs. The heart rate, the systolic and diastolic arterial pressures, left ventricular pressure, peak dp/dt and dp/dt-40 were monitored continuously until return to baseline. Following selective left coronary artery injection, both systolic and diastolic pressures decreased maximally at 5 seconds with parallel changes in peak dp/dt and dp/dt-40. Following the aortic root injection, the blood pressure response was biphasic, increasing at 5 seconds and decreasing maximally at 20 seconds. The corresponding changes in peak dp/dt and dp/dt-40 were initial depression at 5 seconds with quick return to baseline and increase above control at the time of maximal hypotension. The left ventricular end diastolic pressure rose maximally at 5 to 10 seconds for both coronary and aortic injections. The mechanism of hypotension, therefore, varies with the type of angiography. Myocardial depression appears to be a primary factor with selective coronary angiography. However, with aortic root injection, myocardial contractility, although initially depressed, is already improved at the time of maximal hypotension, and thus peripheral vasocilatation is probably the prime mechanism of the hypotension.

Angiocardiography↗