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Biomedical subjects

S Chierchia

Publications and source records attributed to S Chierchia.

107 records · Page 6Linked to original sources
PubMed1978

Coronary vasospasm as a possible cause of myocardial infarction. A conclusion derived from the study of "preinfarction" angina.

To investigate the pathogenesis of myocardial infarction we undertook a systematic study of patients with angina at rest, a syndrome known to evolve frequently into infarction. Among 187 consecutive patients, 37 had infarction, all in the area that showed electrocardiographic changes during angina. In all 76 patients who underwent hemodynamic monitoring, 201thallium myocardial scintigraphy or angiography during angina, a vasospastic origin of the attacks was documented. In six patients with infarction shortly after these studies and in two in whom the infarction developed during hemodynamic monitoring or during angiography the onset of infarction was indistinguishable from the onset of anginal attacks. One patient in whom spasm was observed at the onset of infarction died six hours later; at post-mortem examination, a fresh laminar thrombus was found at the site of the spasm. After infarction, complete thrombotic occlusion of the branch shown to undergo vasospasm was documented in two patients by angiography.

Adult↗
PubMed1976

[Clinical coronarographic characteristics and pathogenetic mechanism of angina pectoris with s-t elevation (author's transl)].

The study of 46 patients with frequent anginal episodes characterized by S-T elevation (so called "variant angina pectoris") demonstrated that this type of electrocardiographic pattern does not characterize a homogeneous group of patients. In fact, while in some patients angina occurred only at rest, in others it occurred also on exercise. Sometimes ecgraphic alterations characterized by S-T depression were observed on the same leads which on other occasions had shown S-T elevation. The angiographic picture revealed: absence of significant coronary alterations in 10% of cases, stenosis greater than 75% in one main branch in 29%, in two branches in 39% and in three branches in 22% of cases. The hemodynamic monitoring carried out on 14 of these patients demonstrated that the ecgraphic modifications occur before the onset of the hemodynamic parameters which control myocardial O2 consumption. This suggests a primitive reduction of regional myocardial blood supply as a cause of the ischaemic episodes. The study of the regional myocardial perfusion with 201Tl technique in 6 patients confirmed this hypothesis. Coronary angiography carried out during an ischemic episode showed that the reduction of myocardial blood supply was caused by a spasm of a large coronary artery involving a long segment of the vessel, reversible by nitroglycerin administration. Aorto-coronary by-pass operation performed on 6 patients was followed by the disappearance of pain in two patients, even though the "by-pass" patency was angiographically proved in two patients.

Adult↗
PubMedDate not supplied

Effects of vasoactive stimuli on coronary vascular resistance in isolated perfused rabbit hearts: no vasospastic response to ergonovine with or without atherogenic diet.

The mechanism of ergonovine-provoked coronary vasospasm is poorly understood. We tested the effect of ergonovine in perfused hearts from normal and cholesterol-fed (18 weeks, 2% cholesterol diet) rabbits in a constant-flow Langendorff perfusion. Aortic perfusion pressure was monitored to measure coronary vascular resistance, and left ventricular pressure was measured with an isovolumetric balloon in the left ventricle. Control coronary vascular resistance was 1.12 +/- 0.11 mm Hg/ml/min in hearts from normal rabbits and 1.53 +/- 0.16 mm Hg/ml/min in hearts from cholesterol-fed rabbits (n = 9 each, mean +/- SEM, p less than 0.05). The cholesterol content of aortae from cholesterol-fed rabbits was markedly increased (432 +/- 85 mg/g protein vs. 14.9 +/- 8.2 in controls, p less than 0.001; for coronaries: 396 +/- 136 mg/g protein vs. 125 +/- 25, p less than 0.05). In both groups, increases in coronary vascular resistance were observed with vasopressin (40 IU/l) and phenylephrine (30 microM) and decreases with adenosine (10 microM), isoprenaline (0.1 microM) and 30 sec stop-flow (all p less than 0.05). Ergonovine maleate (10 microM) and serotonin (10 microM) did not increase coronary vascular resistance. Although in whole heart perfusion small changes in the caliber of epicardial vessels may not be detectable, changes severe enough to produce measurable changes in total coronary resistance were not found. Therefore the absence in our model of an increase in coronary vascular resistance after ergonovine is not compatible with a local direct mechanism in epicardial arterial wall, even when sensitized by a high cholesterol diet.

Animals↗
PubMedDate not supplied

Psychological and physiopathological study on coronary patients.

In this paper the AA have tried to define the relationship between psychopathological characteristics or symptoms and angina attacks in coronary patients. The research plan was agreed upon and carried out as a collaborative program between psychiatrists and internists with the goal of reaching a more comprehensive approach to the psychosomatic patient. In 20 patients suffering from nocturnal angina attacks the polygraphic sleep recording was performed; 10 of them received psychodiagnostic examination (MMPI). In 8 cases during sleep recordings hemodynamic monitoring was also performed. The MMPI data were compared with 82 other individuals who had myocardial infarction (56 ss) and diurnal angina (26 ss) and 34 control subjects without cardiac disease. The results show that the sleep patterns were strongly affected and the most relevant alterations were recorded during the nights with ischemic episodes. No significant correlations were found between ischemic episodes and sleep stages. In no instance did the hemodynamic monitoring show an increase in the parameters related to myocardial oxygen consumption. The psychological data showed that the most severe symptomatology was observed in the nocturnal angina patients where the disease seems to be mostly related to a functional pathogenic mechanism.

Adolescent↗
PubMedDate not supplied

The role of myocardial viability in deriving benefit from reestablishing infarct-related artery flow after acute myocardial infarction.

Early, sustained patency of the infarct-related artery (IRA) induces myocardial salvage, which preserves left ventricular (LV) function and mediates better long-term outcome. However, the time course and the mechanisms of muscle recovery after myocardial infarction are not completely understood. A large body of evidence suggests that most of the improvement occurs during the hospital phase and is related to early and sustained thrombolysis in myocardial infarction 3 flow in the IRA. Nevertheless, the relationship between IRA status and regional and global LV mechanics in the chronic phase of the disease remains controversial. Some late recovery may occur, either spontaneously or after revascularization, even in the absence of documented myocardial ischemia. The interplay between vessel patency, coronary flow grade and severity of the residual stenosis, and the presence of stunned or hibernating myocardium in the area at jeopardy may explain this delayed improvement. Although there seems to be a limited time window in which myocardium can be salvaged, timely testing for viability, particularly in patients with poor LV function, is justified even in a later phase of the disease to challenge potential cardiac recovery.

Animals↗
PubMedDate not supplied

[Magnetic resonance angiography of coronary arteries: assessment in patients with coronary stenosis and control after stent positioning].

INTRODUCTION: Cardiovascular disease remains the leading cause of death in the world. Invasive coronary angiography is currently the only clinical method available to visualize the coronary arteries, with up to 20% of the procedures demonstrating no evidence of severe coronary artery stenoses. We investigated the role of two-dimensional (2D) coronary magnetic resonance angiography (MRA) in patients with suspected coronary arteries disease and to check the placement and the patency of previously placed coronary artery stents. MATERIAL AND METHODS: Eleven patients with suspected coronary artery disease who underwent elective cardiac catheterization with coronary angiography were examined with 2D coronary MRA to detect coronary artery stenoses. Other 11 patients with 13 stented coronary arteries (6 RCA, 5 LAD, 2 Lcx) were prospectively examined with MRA one day to 8 months after stent placement. Eighteen amagnetic stents were imaged. Imaging was performed with a 1.5 T MR unit (GE Signa Horizon Echo Speed) with a phased array multicoil. Segmented k-space fast GE sequences were acquired with and without fat suppression at several cardiac cycle phases within a single breath-hold. Correlation with coronary angiography was performed in all patients. RESULTS: Thirteen significant stenoses were found at coronary angiography in 11 coronary arteries. The sensitivity and specificity of MR coronary angiography, as compared with conventional angiography, in correctly identifying the single vessels with > 50% angiographic stenoses were 73% and 94%, respectively. The corresponding positive and negative predictive values and accuracy were 88%; 84% and 86%, respectively. As far as the study of coronary artery stents is concerned, no MR-related adverse events were observed. The stents were visualized as signal loss areas. The length of the signal loss corresponded to the length of the stents in all 18 cases (r = 97). The patent blood flow distal to the stents appeared as a high-signal band distal to the signal void, corresponding to stent patency at coronary angiography. CONCLUSIONS: Although in an early stage of technical development, 2D coronary MRA can depict 73% of hemodynamically severe coronary artery stenoses. Moreover breath-hold coronary cine MRA is a safe technique to visualize coronary artery stents. Stent site and patency can be noninvasively studied with this technique.

Adult↗