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Failure of experimental atherosclerosis to sensitize coronary arteries to spasm in hypercholesterolemic rabbits.

Since hypercholesterolemia sensitizes isolated rabbit coronary arteries to vasoconstrictor stimuli, we assessed the possibility of reproducing occlusive coronary spasm both in vitro and in vivo in atherosclerotic rabbits. In Langendorff-perfused hearts from nine atherosclerotic rabbits (2% cholesterol diet for 18 weeks), despite a threefold increase of cholesterol concentration in the coronary wall compared with nine control rabbits, ergonovine and serotonin did not produce any increase of coronary vascular resistances; the increase produced by pitressin was significantly less in atherosclerotic than in normal hearts (56 +/- 13% vs 138 +/- 28%, p less than 0.05, respectively), whereas that produced by phenylephrine was similar (10.1 +/- 1.8% vs 8.5 +/- 2.4%, p = n.s.). In eight other unanesthetized rabbits we recorded the ECG during ergonovine administration (0.05 mg/kg) and during hypothalamic stimulation before and at regular intervals during the 2% cholesterol diet; rabbits survived for periods ranging from 1 to 22 weeks (mean 9.6 weeks). Only one animal had ST depression during episodes of marked tachycardia; no ischemic ECG changes were ever observed in the other rabbits despite the diffuse subintimal coronary deposition of cholesterol found postmortem. Thus, in atherosclerotic rabbits with chronic marked hypercholesterolemia, coronary arteries do not develop occlusive coronary spasm as observed in patients with variant angina.

Animals↗

Provocative testing for coronary arterial spasm: rationale, risk and clinical illustrations.

Two cases of Prinzmetal's variant angina are presented in which coronary spasm was documented by electrocardiographic evidence obtained in the coronary care unit during provocative testing with ergonovine maleate after the arteriographic demonstration of anatomically normal coronary arteries. The rationale and risks of provocative testing for spasm in patients with chest pain and anatomically normal coronary arteries are reviewed. The advantages of performing provocative testing in the coronary care unit after arteriography rather than in the catheterization laboratory during coronary arteriography are discussed.

Adult↗

Coronary hemodynamic and myocardial metabolic alterations accompanying coronary spasm.

Arterial pressure, coronary sinus blood flow with the thermodilution technique and calculated coronary vascular resistance were measured and coronary arteriography performed at rest and after the administration of ergonovine in 14 patients with atypical chest pain (group 1) and 6 patients with variant angina (group II). Mild diffuse narrowing of the left coronary bed in group I was not accompanied by S-T segment shifts, and coronary vascular resistance did not change significantly. In contrast, severe focal spasm (greater than 90 percent narrowing) of the left anterior descending coronary artery in group II patients was accompanied by S-T elevation and a marked overall increase in coronary vascular resistance (from 0.65 +/- 0.07 to 1.14 +/- 0.10 mm Hg/ml per min) (P less than 0.005). In addition, the myocardial arteriovenous oxygen difference increased and net lactate extraction changed to lactate production in the two patients in group II in whom these measurements were made. Thus, thermodilution coronary sinus blood flow measurement may be a sensitive method for detecting primary increases in coronary vascular resistance due to a high grade focal spasm in the left anterior descending coronary artery.

Adult↗

Nifedipine in the treatment of unstable angina, coronary spasm and myocardial ischemia.

The effects of nifedipine, a potent calcium antagonist, were studied in patients with unstable angina, coronary spasm and myocardial ischemia. Data from two separate groups of patients studied in the cardiac catheterization laboratory indicate that intracoronary injection of nifedipine promptly reversed coronary spasm--whether provoked or spontaneous--in five of six patients. In other patients, direct intracoronary injection of the drug was compared with intravenous administration. After intracoronary injection, local mechanical cardiac action virtually ceased, and the ventricular wall became thinner during systole. Thus, a specific inhibitory action on contractile energy expenditure could be demonstrated in the presence of increased coronary flow. This "oxygen-sparing" effect was tested in a group of 31 patients with symptomatic unstable angina whose pain at rest, with ST-T changes, had not responded to 8 hours of treatment with maximal beta adrenergic blockade, nitrates and bed rest. The addition of 6 X 10 mg of nifedipine rendered 27 of these patients asymptomatic within 1.5 hours. In the four patients who did not respond, coronary arteriography demonstrated severely stenotic lesions. Two of the four patients subsequently responded to intraaortic balloon pumping and bypass surgery; one patient had a myocardial infarction and one who had a 90 percent reduction in the diameter of the left main coronary artery, died. It is concluded that nifedipine should be added to beta adrenergic blockade therapy if the latter does not appear to be immediately effective. This combination has not been shown to cause any hemodynamic deterioration, and only a minority of the patients treated sustained a myocardial infarction during the first 3 months of follow-up. The use of nifedipine in unstable angina deserves further clinical evaluation.

Adult↗

Exercise-induced coronary spasm with S-T segment depression and normal coronary arteriography.

The unique association of both exercise-induced coronary arterial spasm and S-T segment depression with normal findings on selective coronary arteriography is described. The patient had a prior history of typical effort angina that had recently progressed to angina at rest. Despite the change in anginal pattern, the electrocardiogram disclosed S-T segment depression that was consistent with subendocardial ischemia, during both exercise testing and spontaneous chest pain. Exercise thallium-201 scintigraphy demonstrated the presence of large perfusion defects of the anterior and septal walls of the left ventricle. Coronary arteriographic findings, in the absence of symptoms, were entirely normal. Severe localized, reversible coronary spasm of the proximal left anterior descending coronary artery was subsequently demonstrated during spontaneous angina, isometric arm exercise and after the administration of ergonovine maleate. After treatment with isosorbide dinitrate and nifedipine, the patient had no further chest pain or electrocardiographic changes, and a repeated thallium-201 stress test revealed normal findings and greatly improved exercise tolerance.

Angina Pectoris↗

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↗

Long-term follow-up of verapamil and nitrate treatment for coronary artery spasm.

Thirty-seven patients with coronary artery spasm and minor coronary atherosclerosis (34) or normal coronary arteries (3) were followed up long-term. All had angina at rest, 32 had nocturnal angina, and 13 had a positive exercise test with S-T elevation. Three had a previous subendocardial infarction; 10 had had serious arrhythmias, which caused syncope in 7. At last review, 21 months (range 1 to 61) after starting therapy, 27 patients continued on verapamil, 314 (120 to 600) mg/day; 4 who did not respond to verapamil were taking nifedipine, 58 (30 to 80) mg/day; and 16 were also taking isosorbide dinitrate, 41 (20 to 80) mg/day. Of the 31 patients on therapy, 21 were asymptomatic, 9 were improved (1 to 4 attacks/month), and 1 had an average of 8 anginal attacks/month; the remaining 6 had stopped therapy and 5 were asymptomatic a mean of 10 (3 to 18) months after stopping. The exercise test became negative in all 12 patients tested on therapy, although 3 required nitrates in addition to verapamil or nifedipine. In 26 supervised treatment withdrawals in the hospital, a mean of 15 (1 to 55) months on therapy, 10 developed angina in less than 48 hours. Angina recurred in all 6 unsupervised, patient-initiated withdrawals. Failure to stop smoking was positively associated with recurrence of angina on treatment withdrawal (p less than 0.02). Long-term treatment of coronary artery spasm with verapamil or nifedipine together with isosorbide dinitrate was well tolerated and effectively relieved angina. No documented serious arrhythmias, syncopal episodes, myocardial infarction, or death occurred during follow-up.

Coronary Angiography↗

Long-term responses to nifedipine in patients with coronary spasm who have an initial favorable response.

Twenty-six patients with angina and coronary spasm participated in a randomized crossover trial comparing nifedipine with isosorbide dinitrate. Eighteen patients had a short-term beneficial response to nifedipine, and 14 of these were followed up for an average period of 9.4 months. During follow-up study, nifedipine was the primary therapy in these 14 patients, but other drugs were added when clinically necessary to control angina. There was an overall 86% beneficial response rate (greater than 50% decrease in angina frequency). However, 2 patients had a large increase (greater than 10 times) and 4 patients had a slight increase (transient) in angina frequency over the long term compared with the short-term response. The other 8 patients had a similar angina frequency compared with the short-term response. Of the 12 patients with a good response (transient slight increase or no change), 8 (67%) required additional drug therapy to maintain angina control. Nifedipine was discontinued in 2, and the dose was decreased in 3 of the 14 patients because of adverse effects. Three patients had a marked increase in angina at 9, 14, and 3 months, requiring hospitalization; 1 patient had coronary bypass for symptom control. Thus, patients with coronary spasm selected because of a favorable short-term response to nifedipine were effectively treated over the long term with nifedipine; however, additional therapy was often needed to control symptoms. Adverse effects were common, but simple reduction of nifedipine dose usually diminished the unwanted effects of the drug.

Angina Pectoris↗

Clinical studies of patients with coronary spasm.

Coronary artery spasm may cause myocardial ischemia in patients without severe coronary atherosclerotic obstruction. Spontaneous rest angina, particularly at night, is the predominant symptom; most patients are smokers. Ergonovine tests have high sensitivity and specificity for the diagnosis of coronary spasm, but should be used when vasospasm is suspected but no electrocardiogram was recorded during spontaneous angina. Arterial constriction measured during ergonovine testing suggests that the arterial hypersensitivity to vasoconstrictors at sites of atherosclerotic lesions is independent of the severity of the lesion. Coronary vasospasm may also be provoked by exercise, possibly through an alpha-adrenergic mechanism. Both spontaneous and exercise-induced attacks of vasospasm are prevented by calcium-antagonist drugs that remain effective during longer-term treatment. The cyclic nature of the condition is demonstrated when successful therapy is discontinued without recurrence of symptoms and may be due to alteration of arterial hypersensitivity.

Angina Pectoris↗

Coronary hemodynamic responses during spontaneous angina in patients with and patients without coronary artery spasm.

The mechanisms of spontaneous angina were evaluated during cardiac catheterization in 13 patients who had angina occurring without provocation at rest. Left ventricular and systemic hemodynamics, coronary venous flows (thermodilution technique), electrocardiogram and coronary angiograms were recorded before and during spontaneous angina. Angiography during spontaneous angina showed that 5 patients had coronary spasm (group I) and 8 patients did not (group II). In group II there was a preponderance of multivessel coronary artery disease. Left ventricular end-diastolic pressure increased in all patients in both groups during spontaneous angina. In group I, 4 patients had transient ST elevation and 1 patient had peaked T waves during angina. Transient ST depression occurred during spontaneous angina in all group II patients. Group I patients had decreased coronary sinus flow (4 of 5 patients) or decreased regional flow (5 of 5) during spontaneous angina. Coronary resistance and ratio of double product to coronary blood flow increased in all patients. In group II, coronary hemodynamic responses during spontaneous angina varied. Coronary venous flows, coronary resistance and ratio of double product to coronary blood flow showed no uniform pattern. Thus, patients with severe coronary artery disease can have spontaneous angina without angiographic findings of coronary spasm. After analysis of angiograms and coronary hemodynamics in these patients, no apparent uniform mechanism for spontaneous angina was found.

Aged↗

Nicardipine for angina pectoris at rest and coronary arterial spasm.

The antiischemic effects and safety of nicardipine were assessed in 17 patients with angina at rest and coronary arterial spasm in a randomized placebo-controlled study over 8 to 13 weeks. Eleven patients had previously had unsatisfactory results with long-acting nitrates or other calcium blockers. The average daily dosage of nicardipine for optimal angina relief was 89 mg (range 40 to 160). During the double-blind phase, angina frequency decreased with nicardipine compared with placebo (mean 0.47 vs 2.11 attacks/day, p less than 0.05). A similar decrease in nitroglycerin requirements occurred (0.51 vs 2.77 tablets/day, p less than 0.05). During placebo periods, 51 episodes of ischemic ST-segment shifts occurred during 482 hours of ambulatory electrocardiographic monitoring and 12 (24%) were associated with angina. During nicardipine treatment, only 15 episodes of ST-segment shifts occurred during 498 hours of monitoring. In 1 patient a burning skin rash developed; otherwise, the drug was generally well tolerated. Thus, nicardipine is effective and safe in preventing symptomatic and asymptomatic ischemia in patients with coronary spasm. It may be particularly beneficial in patients with unsatisfactory responses to other therapy.

Aged↗

Effect of intact endothelium against platelet-induced coronary artery spasm in isolated rabbit hearts.

Effects of collagen-activated washed rabbit platelets on coronary arteries with and without intact endothelium were studied in a supported rabbit heart preparation using a perfluorocarbon (FC-43) as perfusate. The vascular diameter of obtuse marginal coronary arteries was determined by means of gated color arteriography (injection of patent blue dye). Endothelial denudation of the obtuse marginal artery was accomplished by scraping the lumen with a roughened plastic tubing. Injection of washed platelets (10 ml with about 500,000 platelets/microliters) not treated with collagen failed to constrict coronary arteries either with intact or denuded endothelium. In contrast, injection of platelet suspension immediately after activation with collagen caused vasoconstriction of denuded obtuse marginal coronary arteries in 10 of 14 cases. In 6 preparations occlusion was complete, lasting up to 16 minutes. In arteries with intact endothelium, no coronary vasoconstriction occurred. In hearts with coronary artery spasm, total coronary vascular resistance increased significantly. This study furnishes additional evidence that endothelial lesions are a contributory factor for large coronary artery spasm and that endothelial cells possess a protective function against vasoconstrictor substances released from aggregating platelets.

Animals↗

Late follow-up (41 to 102 months) of medically treated patients with coronary artery spasm and minor atherosclerotic coronary obstructions.

From a series of 37 patients with coronary artery spasm and less than 70% diameter narrowing treated initially with verapamil and nitrates, 33 were followed up 41 to 102 months (mean 62). One patient died from carcinoma of the lung and 3 could not be traced. Before diagnosis, 3 had nontransmural myocardial infarction and 10 had either ventricular tachycardia and fibrillation or atrioventricular block. During follow-up there were no cardiac deaths or myocardial infarctions. Asymptomatic periods of more than 3 months occurred in 23 patients during follow-up: 18 with asymptomatic periods of more than 1 year were pain free at the time of study and 5 with asymptomatic periods of 3 to 6 months had infrequent pain. Ten patients had no asymptomatic periods. Symptomatic status at last review was related to initial response to therapy: 13 of 18 patients (72%) currently asymptomatic became asymptomatic with initial therapy compared with 5 of 15 patients (33%) currently experiencing pain (p = 0.06). Twenty-six patients were currently receiving therapy: 22 verapamil, 80 to 640 mg/day (mean 280), 2 nifedipine, 1 diltiazem and amiodarone and 1 isosorbide (15 were receiving additional isosorbide). Twelve patients were not receiving therapy or were receiving very low dosage therapy, including 8 with asymptomatic periods of more than 1 year. Patients with coronary spasm and less than 70% diameter narrowing treated medically have low mortality and morbidity rates over 5-year follow-up. Many have long asymptomatic periods and some may be able to stop therapy indefinitely.

Coronary Disease↗

Effect of oral levodopa and carbidopa on coronary spasm in variant angina pectoris.

The effect of oral administration of 500 mg of levodopa with 50 mg of carbidopa, a peripheral dopadecarboxylase inhibitor, on coronary vasomotion during vasoconstrictor stimuli was examined in 15 patients with variant angina presenting with hyperventilation-induced myocardial ischemia. Patients were studied during 3 noninvasive sessions and 1 angiographic session. In all sessions the basic protocol consisted of provocation of coronary spasm by hyperventilation before and 2 hours after levodopa and carbidopa administration. During angiography, great cardiac vein blood flow, right atrial and aortic pressures were measured, and coronary angiograms were recorded at baseline and 1 to 4 minutes after each hyperventilation. Samples for dopamine plasma levels were drawn before and throughout the studies. In 3 selected patients, levodopa and carbidopa were associated with 30 mg of domperidone, an antagonist of dopamine peripheral receptors. Levodopa and carbidopa consistently prevented the occurrence of ischemia after hyperventilation in 6 of the 15 patients. This was due to inhibition of local coronary spasm in 2 patients and reduced coronary constriction in 4. Ischemia due to hyperventilation was still prevented despite addition of domperidone with levodopa and carbidopa. Plasma dopamine levels were 23 +/- 15 before and 739 +/- 284 pg/ml 2 hours after administration of levodopa and carbidopa. These findings are consistent with either a decreased central dopaminergic activity and associated disregulation of vasomotor tone, or a peripheral vasodilatory effect of increasing dopamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Influence of exercise-induced coronary artery spasm on thallium-201 initial distribution and washout kinetics in patients with variant and classic angina pectoris.

Thallium-201 single-photon emission computed tomography was performed immediately, and 2 and 4 hours after exercise-induced anginal attack in 2 groups of patients with either exercise-induced coronary spasm or severe fixed stenosis on the isolated proximal left anterior descending coronary artery. All patients with variant angina had transient ST-segment elevation during the exercise-induced attack for thallium-201 scintigraphic study. Both perfusion defects and 4-hour washout abnormalities were significantly greater in patients with variant angina than in those with stable effort angina (p < 0.01). In patients with stable effort angina, thallium-201 activity in ischemic regions (as a percentage of initial count in the normal region) progressively decreased, whereas in patients with variant angina it increased from 38% (initial) to 48% (2 hours), and then declined to 42% (4 hours). The initial normalized thallium-201 activity in the ischemic regions was significantly lower in patients with variant angina than in those with stable effort angina (p < 0.001). In conclusion, perfusion and washout abnormalities during exercise-induced angina are greater in patients with variant angina than in those with stable effort angina. Exercise-induced coronary spasm seems to contribute to the profound reduction in initial thallium-201 distribution and delayed thallium-201 accumulation in the ischemic region.

Adult↗

Coronary artery spasm after aortic valve replacement.

We report a patient who received aortic valve replacement and experienced early postoperative coronary artery spasm, which led to inferolateral myocardial infarction. The spasm was unresponsive to conventional medication. However, after systemic circulatory and respiratory control, a good prognosis was obtained.

Aortic Valve↗

Coronary artery spasm in the rat induced by hypothalamic stimulation.

Anesthetized rats were sterotaxically implanted with electrodes and electrically stimulated in the lateral hypothalamus. During elevation of the S-T segment on simultaneous precordial electrocardiograms, the heart was perfused with glutaraldehyde-paraformaldehyde fixative and the major coronary arteries prepared for morphometry of luminal dimensions. A similar procedure was performed in a second group receiving intravenous arginine vasopressin (AVP) in place of hypothalamic stimulation. Elevation of the S-T segment was present in these animals as well. Control animals were implanted, not stimulated and otherwise treated in the same way. Morphometry showed that reductions of mean luminal diameter and cross-sectional area of statistical significance occurred in the two experimental groups compared to controls, suggesting that coronary spasm was the cause of the elevated S-T segments. Pooled plasma from separate groups of implanted control and hypothalamically-stimulated animals revealed substantial elevation of AVP levels in the latter raising the possibility that the neuroendocrine was involved in eliciting coronary artery spasm.

Animals↗

Fibromatosis of dura presenting as infantile spasms.

A 6-month-old boy developed emprosthotonic infantile spasms and right hemiparesis. CT scan revealed a large mass related to a distended right temporal horn which on craniotomy proved to be a hard white tumour of the tentorium cerebelli which could be only incompletely resected. Microscopically and ultrastructurally, this lesion proved to be a typical fibromatosis containing myofibroblasts which invaded the brain. The child made an excellent recovery and is well a year after surgery. This case is another example which argues for full investigation of cases of infantile spasms which usually carry such a dismal prognosis.

Cerebellar Neoplasms↗