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Biomedical subjects

R L Feldman

Publications and source records attributed to R L Feldman.

At least 109 records · Page 6Linked to original sources
PubMed1983

Influence of acute aortic insufficiency on the hemodynamic importance of a coronary artery narrowing. II. Various magnitudes of aortic insufficiency.

Coronary hemodynamic effects of controlled acute aortic insufficiency were studied in 40 open chest dogs with and without graded coronary diameter narrowing. An adjustable basket device was used to regulate aortic insufficiency, creating three groups: group 1, mild to moderate aortic insufficiency (regurgitant fraction less than 50%); group 2, moderately severe aortic insufficiency (regurgitant fraction greater than 50%); and group 3, aortic insufficiency with mean aortic pressure restored to control levels. Mean coronary blood flow was similar to control values in group 1, but was higher in groups 2 and 3. The endocardial/epicardial flow ratio was similar with and without aortic insufficiency. With graded coronary narrowing greater than 80%, coronary flow and endocardial/epicardial flow ratio decreased with or without aortic insufficiency. However, endocardial/epicardial flow ratio usually decreased more during aortic insufficiency. Peak reactive hyperemic flow after release of a 10 second coronary occlusion also decreased during aortic insufficiency. The amount of decrease compared with control values was related to the magnitude of aortic insufficiency. This value with no coronary narrowing in group 1 was similar to peak reactive hyperemic flow with a 60% coronary narrowing during the control period. In group 2, peak reactive hyperemic flow was similar to that with an 80% coronary narrowing during the control period. Restoring mean aortic pressure to control values in group 3 did not restore peak reactive hyperemic flow to control values. These data suggest that coronary flow reserve assessed with coronary narrowings or during reactive hyperemia is decreased during aortic insufficiency. The decrease in coronary flow reserve was more pronounced as the magnitude of aortic insufficiency increased.

Animals↗
PubMed1983

Regional coronary venous flow responses to transient coronary artery occlusion in human beings.

Coronary hemodynamic responses to transient coronary artery occlusion in 21 patients were investigated by using regional coronary venous thermodilution to measure regional coronary venous flows. Transient coronary artery occlusion was produced by coronary artery spasm (13 patients) or balloon inflation during coronary angioplasty (8 patients). The left anterior descending coronary artery was transiently occluded in 12 patients, the right coronary artery in 8 patients and the left circumflex artery in 1 patient. During transient coronary occlusion, regional venous flow decreased in 20 of the 21 patients (79 +/- 31 to 53 +/- 29 ml/min, mean +/- standard deviation [SD]; probability [p] less than 0.05) corresponding to the left ventricular region perfused by the occluded artery. Regional coronary resistance increased in all 21 of these regions (1.42 +/- 0.75 to 2.26 +/- 1.45 mm Hg/ml per min, p less than 0.05). Simultaneously measured blood flow and resistance in the left ventricular region supplied by the nonoccluded arteries did not change significantly (62 +/- 27 to 64 +/- 29 ml/min and 1.85 +/- 0.93 to 1.81 +/- 0.98 mm Hg/ml per min, respectively). Coronary hemodynamic changes were similar during transient coronary occlusion, whether produced by coronary spasm or by balloon inflation. However, the presence of angina, reversible electrocardiographic abnormalities and an increase of the left ventricular filling pressure were more common during coronary spasm (p less than 0.05 for all). Regional coronary hemodynamic changes during transient occlusion of the anterior descending, circumflex or right coronary artery were similar. These data show that coronary occlusion decreases regional left ventricular flow in the region perfused by the affected artery. The method of coronary occlusion or the coronary artery affected during occlusion did not seem to elicit different responses.

Adult↗
PubMed1983

Comparison of early and long-term results with intraoperative transluminal balloon catheter dilatation and coronary artery bypass grafting.

Twenty-six patients with chronic stable angina underwent intraoperative coronary artery balloon catheter dilatation and concomitant coronary artery bypass grafting (CABG). In one patient (3.8%) the catheter could not be passed through the arterial narrowing, and in two patients (8%) early angiographic evidence for arterial damage was detected. Postoperative angiographic data were available in 85% of patients early (mean 10 days) and in 50% of patients late (mean 12 months). Early results showed one perioperative myocardial infarction, 100% relief of angina, and no operative mortality. Compared to preoperative studies, of 23 angiographically visualized distal narrowings dilated in an antegrade fashion, 12 (52%) were unchanged, two (9%) were worse, and nine (39%) were improved. Those arterial segments with discrete distal narrowings (n = 13) had better angiographic results than those with diffuse distal narrowings (n = 9). In 49% of the former and in 22% of the latter arterial narrowings, improvement (increased luminal diameter) was documented postoperatively. In addition, there were four proximal narrowings which were dilated in a retrograde fashion; three were unchanged and one was improved compared to preoperative studies. Only one of 27 dilated segments (3%) was totally occluded postoperatively. Late results showed two patients (8%) developed recurrent chest pain and one patient (4%) died related to congestive heart failure. The two patients who had angiographically documented coronary arterial intimal injury showed evidence of resolution at late study. In 13 distal narrowings, six (46%) were unchanged, three (23%) were worse, and four (31%) were improved compared to the preoperative appearance. In 10 distal narrowings visualized both early and late postoperatively, nine were unchanged and one was worse. In summary, coronary artery balloon catheter dilatation during CABG is relatively safe and is associated with acceptable clinical results. Angiographic evidence for improvement is less than symptomatic relief postoperatively. Therefore, objective evaluation may be necessary for accurate determination of operative results. The need for a national registry related to intraoperative angioplasty is probably warranted.

Angina Pectoris↗
PubMed1982

Short- and long-term responses to diltiazem in patients with variant angina.

Short- and long-term effects of diltiazem on angina frequency were studied in 12 patients with variant angina (pain at rest with S-T elevation). Each patient first entered a double-blind short-term trial. Either diltiazem, in two dosage schedules (120 and 240 mg/day), or placebo was administered in a randomized double-blind program over 10 weeks. Significant decreases in frequency of angina were observed when diltiazem treatment periods were compared with placebo periods. Six patients were asymptomatic, one had 50 percent or greater decrease, and two had a smaller decrease in angina frequency. Two patients showed no important improvement during short-term diltiazem therapy. One patient experienced ventricular fibrillation in the placebo period and was advanced to treatment with open label diltiazem before responses could be ascertained in the double-blind trial. All other patients were then advanced to open label diltiazem therapy and followed up for an average of 16 months (range 8 to 23). Responses during the short-term trial accurately predicted responses during long-term therapy. Of the six patients who were asymptomatic during short-term therapy, five remained asymptomatic and one had rare episodes of angina. One other patient continued to have a good response (50 percent or greater decrease in angina frequency) and two other patients had a partial response. The two patients who did not respond during short-term therapy did not respond during long-term therapy.

Adult↗
PubMed1982

Randomized double-blind comparison of nifedipine and isosorbide dinitrate in patients with coronary arterial spasm.

The effects of nifedinpine and isosorbide dinitrate on the frequency of angina and consumption of nitroglycerin were studied in 19 patients with coronary arterial spasm. After a lead-in phase, the patients were randomized to treatment with either nifedipine or isosorbide dinitrate. After dose titration (40 to 120 mg/day) and evaluation, they were given the alternate therapy. During the initial segment of the double-blind phase, one patient died suddenly (nifedipine phase), one dropped out of the study (nifedipine phase) and another was unable to tolerate therapy (isosorbide dinitrate phase). In the other 16 patients, the mean frequency of angina was less during therapy with both nifedipine (0.69 episode/day, p less than 0.05) and isosorbide dinitrate (0.77 episode/day, p less than 0.05) phases than during the lead-in phase (1.71 episodes/day). The mean frequency of angina was similar in the nifedipine and isosorbide dinitrate phases. A 50 percent or greater decrease in frequency of angina compared with lead-in phase values occurred in 13 of 18 patients during treatment with nifedipine and in 10 of 16 during treatment with isosorbide dinitrate. Of the 16 patients who completed both double-blind phases, 7 showed greater improvement (that is, a 50 percent or greater decrease in frequency of angina) with nifedipine than with isosorbide dinitrate); 6 others showed greater improvement with isosorbide dinitrate, and the other 3 had a less than 50 percent difference in frequency of angina with the two drugs. These findings in a limited number of patients suggest that both nifedipine and isosorbide dinitrate are effective in certain patients with coronary spasm but that neither drug is clearly superior.

Adult↗
PubMed1982

Effects of selective injection of contrast media on coronary artery diameter.

The purpose of this study was to quantify the effect of Renografin-76 on epicardial coronary artery diameters, during selective coronary angiography. Using 105 mm-photospot angiograms taken at 0, 1, and 5 min, 99 coronary segments from ten patients were measured. Comparing the angiograms at 1 and 5 min to the control angiograms, a 7 +/- 7% and 6 +/- 7% (both p = NS) change in diameter respectively was noted. Comparing the 1 and 5 min angiograms, there was no significant change (-1 +/- 7%). Measurements were found to be very reproducible. This study shows that there is a trend toward dilation of the coronary arteries during selective coronary angiography, but this did not reach statistical significance and probably is not clinically important.

Adult↗
PubMed1982

Ergonovine-induced esophageal spasm in patients with chest pain resembling angina pectoris.

We studied the effect of ergonovine maleate (EM) on esophageal motor activity in 18 consecutive patients with angina-like chest pain. Significant coronary artery disease was excluded in each patient by cardiac catheterization studies. Baseline esophageal motility was abnormal in 12 patients (66%). After injection of EM, ten patients developed their typical chest pain at the onset of repetitive contractions. Thus, chest pain and esophageal dysfunction were clearly linked. Compared with saline injection, only the repetitive contractions were significantly increased after AM in these patients (P less than 0.01). Amplitude and duration of contractions were increased after EM, but not significantly. Due to potentially serious adverse effects, however, EM cannot be recommended for routine use as a provocative agent.

Adult↗
PubMed1982

Regional coronary artery dilation response in variant angina.

We examined segmental left coronary artery responses to nitroglycerin in 17 variant angina patients and in 34 nonvariant angina patients using a quantitative angiography technique. In those patients with left anterior descending vasospasm, there was a marked exaggeration in the degree of dilation to nitroglycerin in those segments which at other times were involved with spasm. This observation was consistent when these segments were compared to (1) other left coronary segments in the same patient, (2) the same left coronary segments in nonvariant angina patients, and (3) the same left coronary segments in patients with right coronary spasm. These data suggest that a localized disorder in coronary vasomotion is present in patients with coronary spasm that is not limited to constriction but also involves increased dilation in response to nitroglycerin.

Adult↗
PubMed1982

Coronary artery spasm: prevalence, clinical significance, and provocative testing.

Recent clinical and laboratory observations indicate that coronary artery spasm may play a role in the pathophysiology of ischemic heart disease. The majority of patients with ischemic heart disease have coronary atherosclerosis. The prevalence of coronary artery spasm in these patients is unknown. However, current evidence suggests that patients with rest angina have a higher incidence of coronary artery spasm than do patients with reproducible effort angina. Coronary artery spasm may initiate or contribute to acute myocardial infarction, but recent evidence obtained in patients undergoing thrombolytic therapy during the early phases of myocardial infarction suggests that it is not a common occurrence. Although numerous examples of ventricular tachycardia and ventricular fibrillation occur during episodes of coronary artery spasm, the incidence of coronary artery spasm in association with sudden death is unknown. Provocative testing with ergonovine maleate reveals that the highest incidence of provocable coronary artery spasm is found in patients with rest angina. In patients with the syndrome of variant angina, coronary artery spasm is nearly always provocable.

Angina Pectoris↗
PubMed1982

Variability of electrocardiographic responses to repeated ergonovine provocation in variant angina patients with coronary artery spasm.

We reviewed our experience with serial ergonovine provocative tests for coronary artery spasm (CAS) in ten variant angina patients with angiographically proved CAS. Of the 26 ergonovine tests performed in the ten patients, only four patients exhibited reproducible ECG response to ergonovine. The remaining six patients had variable and unpredictable ECG responses to ergonovine. All patients were in an active phase of their disease. The variability of ST segment directional response to ergonovine is considered to be on the basis of disparate sensitivity of the coronary circulation to intravenous ergonovine. Because of this variable response, the ECG response alone should not be considered as the standard indicator for CAS presence but should be utilized with other hemodynamic and angiographic criteria.

Angiography↗
PubMed1982

Effects of carbon dioxide, Nd-YAG, and argon laser radiation on coronary atheromatous plaques.

Laser radiation has been successfully applied in several areas of medical practice. However, its use in cardiology and specifically its effects on obstructive atherosclerosis have largely been unexplored. To evaluate effects of laser radiation on atherosclerotic plaques 25 fresh necropsy atherosclerotic coronary artery segments were exposed to laser radiation with either a carbon dioxide, Nd-YAG, or argon laser. Split or intact segments were prepared under dry conditions or while immersed in saline solution or blood and exposed to laser radiation as power and duration of exposure varied. All 3 lasers were capable of creating controlled injury to atherosclerotic plaques. In general, the magnitude of injury varied according to the total energy delivered (that is, power times duration of exposure. Calcified and noncalcified plaques were penetrated with similar levels of injury. Histologic examination demonstrated that laser radiation produced a wedge incision in the atherosclerotic plaque which was surrounded by zones of thermal and acoustic injury.

Argon↗
PubMed1982

Regional coronary hemodynamic responses to cold stimulation in patients without variant angina.

The responses to cold in patients with exertional chest pain were studied by measuring coronary sinus and great cardiac vein flows, aortic and left ventricular pressure and diameters of epicardial and small (0.4 to 1.0 mm) intramyocardial coronary arteries before and after the left hand of 18 such patients was immersed in ice water. Coronary sinus and great cardiac vein flows were used as indexes of total and anterior left ventricular flows. Coronary sinus flow minus great cardiac vein flow was used as an index of inferior left ventricular flow. Perfusion of left ventricular regions was considered potentially "normal" or "abnormal" according to the presence or absence of 50 percent or greater stenosis of luminal diameter in the coronary artery supplying a given region. With cold stimulation, increases occurred in heart rate (6 beats/min), mean aortic pressure (22 mm Hg) and left ventricular end-diastolic pressure (8 mm Hg) (all p less than 0.05). Left ventricular flow in normally perfused regions increased as resistance decreased. Left ventricular flow in abnormally perfused regions increased slightly and resistance increased. Regional left ventricular flow increased more, and changes in resistance differed in normally and abnormally perfused regions. Coronary arterial diameter decreased only minimally (6 percent) in both normal and abnormal left ventricular regions. These data show that cold stimulation increases coronary resistance in abnormally perfused left ventricular regions. Cold stimulation-related increases in coronary resistance do not appear to be caused by coronary arterial "spasm."

Adult↗
PubMed1982

Multiclinic controlled trial of diltiazem for Prinzmetal's angina.

To assess the efficacy of a new calcium entry blocker, diltiazem (Cardizem), for prophylaxis of Prinzmetal's angina, 48 patients were studied in randomized, multiple crossover multiclinic study (2 weeks single-blind, 8 weeks double-blind). Diltiazem dosage in one crossover phase was 120 mg per day; in the other, 240 mg per day. Therapeutic response was measured by patients' diary records of angina frequency and nitroglycerin tablet consumption. Treatment with 120 mg of diltiazem per day reduced angina by 41 percent from the entry placebo period and 20 percent from the paired placebo period (p less than 0.005). Treatment with 240 mg of diltiazem per day reduced angina frequency by 68 percent from the entry placebo period and 43 percent from the paired placebo period (p less than 0.01). There were similar reductions in nitroglycerin consumption. Adverse experiences that may have been related to the medication were noted in only 5 percent of patients. There were no alterations in blood pressure or heart rate. The PR interval increased 3 percent at the 240 mg dosage level. We conclude that diltiazem is an effective and safe agent for control of symptoms of Prinzmetal's angina.

Adult↗
PubMed1982

Preliminary experience with intraoperative transluminal balloon-catheter dilation and coronary artery bypass grafting for the treatment of symptomatic diffuse coronary artery disease.

Transluminal balloon-catheter dilation of coronary artery lesions has become increasingly common in the cardiac catheterization laboratory. We describe a method of intraoperative dilation that may improve surgical results when used in combination with coronary artery bypass graft (CABG) operations in patients with diffusely diseased coronary arteries. In 16 patients, long-segment intraoperative dilations were performed to enlarge luminal narrowings in 21 different regions. All of these patients had postoperative coronary angiography and left ventriculography so that we could objectively evaluate the coronary dilatations. There were no operative deaths or perioperative myocardial infarctions, and angina was relieved in all patients. Of the 21 dilated segments, 12 (57%) were unchanged, 2 (10%) became worse, and 7 (33%) were improved postoperatively. In addition, two new areas of intimal damage were detected in patients with unchanged postoperative liminal diameters. We conclude that further experience and longer follow-up are necessary before the efficacy of intraoperative coronary artery balloon-catheter dilation can be accurately determined.

Angioplasty, Balloon↗