Biomedical subjects
Publications and source records attributed to R L Feldman.
A quantitative coronary arteriographic technique is described utilizing 105-mm photospot angiography and a hand-held optical magnifying device. This technique is rapid, accurate, and reproducible. We feel this technique has potential in evaluating coronary responses to acute interventions and in the long term evaluation of progression or regression of atherosclerotic disease.
Explore the source record for details and available documents.
In summary, it is hazardous to rely solely on coronary angiography to define critical coronary stenosis. Clinically, the physiologic significance of a narrowing observed at coronary angiography can best be evaluated by obtaining additional evidence of myocardial ischemia, i.e. stress testing with ECG monitoring, resting and exercise isotope perfusion studies or ventriculographic studies. However, when evaluating coronary angiograms for critical coronary stenosis, several points are worth considering. First, a long narrowing will decrease coronary blood flow more than a short narrowing of the same severity. Second, sequential narrowings will decrease coronary blood flow more than a single narrowing of the same total length. Third, a long narrowing can be estimated more accurately than a short narrowing. Fourth, caliper measurements of coronary artery narrowings are more accurate than subjective estimation, and fifth, coronary artery dilators may increase the percentage narrowing in some cases. The complex effects of percent stenosis and length of stenosis on the physiology of coronary blood flow must always be considered when evaluating angiograms. In addition, the angiographic or photographic artifacts produced by short narrowings tend to overestimate the percent stenosis and, thus, calipers should be used to measure percent stenosis, especially in the short narrowings.
The coronary hemodynamic effects of controlled aortic insufficiency (AI) were studied in 10 dogs. Coronary blood flow (CBF), before and during reactive hyperemia (RH) with graded coronary diameter narrowings (CN), aortic (Ao) and left ventricular (LV) pressures (P), and aortic blood flow (AoF) were recorded. Opening an adjustable basket catheter, positioned across the aortic valve, created reversible AI quantitated from phasic AoF. AI was regulated so that mean CBF was similar with or without AI. During AI, heart rate and systolic AoP were unchanged, but diastolic AoP declined 14 mm Hg (mean) and end-diastolic LVP increased 8 mm Hg, both p less than 0.05. With CN greater than or equal to 85%, mean CBF decreased with or without AI. Coronary resistance was similar with or without AI. During AI with no CN, peak RH CBF declined significantly and was similar to peak RH with 70% CN without AI. Furthermore, AI with 60% CN caused additional reduction in peak RH and was similar to peak RH with 80% CN without AI. These data suggest that CBF reserve, exposed during RH, is decreased during AI. With AI, a given CN has coronary hemodynamic properties similar to higher degrees of CN without AI. These results may relate to clinical findings of ischemia in patients with AI and no or moderate CN.
Although considerable investigation has been devoted to the concept of "critical" coronary stenosis, there is general lack of agreement on which coronary stenoses consistently decrease coronary blood flow (CBF). In 32 open-chest dogs we studied CBF and the aorta-distal coronary pressure gradient at rest and with reactive hyperemia (RH) as stenoses were created in the left coronary artery (LCA) or its major branches--anterior descending (LAD) or circumflex (LCx) arteries. The effects of stenosis location, reduction in stenosis diameter, stenosis length, and the number of stenoses were studied. Resting CBF and resting distal coronary pressure were decreased by short snare stenoses, which reduced the diameter of the LCA or either major branch more than 80%. Lengthening 50 to 60% LAD or LCx stenoses decreased CBF and increased the pressure gradient. There were small increases in pressure gradients but no change in CBF with multiple stenoses in either the LAD or LCx branch. During peak RH, CBF was decreased by a 60% LCA or branch snare stenosis. Peak RH CBF responses decreased further as length of an LAD or LCx stenosis increased. Multiple stenoses affected peak RH CBF responses significantly more than a single stenosis of the same total length. These data indicate that several anatomic variables of coronary stenosis affect the physiological responses of the coronary circulation. The variables are (1) reduction in lumen diameter, (2) length of stenosis, and (3) number of stenoses in one vessel.
The hemodynamic significance of the length of a coronary arterial narrowing is unclear. Accordingly, the influence of the length of a given coronary narrowing on coronary hemodynamic responses was studied in 14 dogs. Recordings were made as short fixed diameter reductions were progressivley lengthened to 5, 10 and 15 mm by the addition of plastic occluders. Resting coronary blood flow decreased and pressure gradients developed across short (snare) narrowings greater than 80 percent (critical stenosis). Short 40 to 60 percent narrowings had no significant resting hemodynamic influence, but increasing their length to 10 and 15 mm consistently resulted in significant pressure gradients and flow reductions. Reactive hyperemic coronary blood flow expressed as repayment of flow debt (after 10 seconds of coronary occlusion) decreased progressively as these narrowings were lengthed. The effect of 15 mm long narrowings on resting and reactive hyperemic flows was similar to that of short 90 percent narrowings. These data indicate that there is uncertainty about the significance of coronary diameter reductions previously considered hemodynamically unimportant. In our studies, significant changes in resting and reactive hyperemic coronary flows and resting pressure gradients occurred as the length of a given degree of narrowing was increased.
Explore the source record for details and available documents.
Angiographic evidence of unusual vasomotor responses occurred in two patients after administration of sublingual nitroglycerin. In these patients, right coronary arterial segments that appeared angiographically normal before the administration of nitroglycerin showed narrowing after nitroglycerin. Adjacent segments in each of these vessels, as well as the other coronary arteries, dilated as expected. Both patients remained asymptomatic. Repeated administration of nitroglycerin did not alter the anglographic appearance of these vessels. No reason for the localized reduction of coronary arterial diameter was apparent. The possibility that nitroglycerin was associated with these unusual changes is an additional argument against the routine administration of nitrates before coronary arteriography.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The coronary hemodynamic influence of a series of coronary arterial narrowings was compared with single narrowings of the same total length and reduction in diameter in 12 dogs. Compared with single narrowings, two or three sequential narrowings had no significant effect on restng coronary blood flow. Small but significant mean pressure gradients were found for series of two and three 1-mm narrowings but not for single narrowings of the same total length. During reactive hyperemia, repayment of the debt in flow decreased significantly for single 2-mm and 3-mm narrowings, compared with 1-mm single narrowings. An additional decrease in repayment of the debt in flow occurred for two and three separate narrowings, compared with single narrowings. Our findings imply that when the reduction in the diameter of the coronary artery is fixed, an increase in the length or number of narrowings in series reduces the responses of coronary blood flow during reactive hyperemia.
A patient who had endocarditis on a prosthetic aortic valve and who had undergone two aortic valvular replacements developed classic angina pectoris. Cardiac catheterization revealed an aneurysm of the left sinus of Valsalva, which constricted a proximal segment of the left circumflex coronary artery during systole. This type of dynamic coronary arterial narrowing has not been previously described secondary to an aneurysm of a sinus of Valsalva and may be responsible for this patient's manifestations of ischemia.
Explore the source record for details and available documents.
A case of massive hemothorax complicating heparin anticoagulation for pulmonary thromboembolism is presented. Hemothorax complicating anticoagulant therapy for PTE usually occurs within the first week of treatment and is invariably on the side of the initial clinical symptoms, suggesting intrapleural rupture of a hemorrhagic pulmonary infarct. Late hemothorax is unusual and may not be on the side of the initial symptoms, suggesting a different pathogenesis. Hemothorax may occur as the only bleeding complication of anticoagulation and when coagulation studies are within an acceptable therapeutic range. Cessation of anticoagulation therapy and prompt evacuation of the pleural space are recommended.
Explore the source record for details and available documents.
A review of the literature suggested a possible relationship between low self-disclosure or avoidance of the self in parents and stuttering in the child within the same family. The present research was designed to test whether there are any differences in self-disclosure between parents of stuttering children and parents of nonstuttering children. The Self-Disclosure Questionnaire, devised by Jourard, was administered to 64 mothers and 64 fathers, half of whom comprised the control groups. The results obtained by analyses of variance indicated that parents of stuttering children do not differ from parents of nonstuttering children in their actual self-disclosure. However, findings as to why disclosure did not occur on certain items indicated that, although the parents of stuttering children do not differ in self-disclosure, they may differ in declining to disclose information when asked for it.
Explore the source record for details and available documents.