Background and objective. Evaluation of hemodynamics in patients with acute myocardial infarction is crucial. In clinical practice, the comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old. Such investigations are often analyzed inappropriately, notably by using correlation coefficients. Our objective is to present an alternative approach, suggested by D. G. Altman and J. M. Bland, based on graphical techniques and simple calculations, for evaluation of the agreement of two methods – intermittent thermodilution (recognized and accepted as a “gold standard” for hemodynamic monitoring) and impedance cardiography (newly introduced method). Patients and methods. A total of 34 patients (20 (58.8%) men and 14 (41.2%) women) were investigated according to the study protocol at Kaunas University of Medicine Hospital. A prospective controlled study was designed to compare two different methods – intermittent thermodilution and impedance cardiography – of cardiac output measurement simultaneously in patients with acute myocardial infarction. Statistical analysis was performed with Bland–Altman and linear regression. Results. A total of 34 paired measurements were carried out in 34 patients at the initiation of hemodynamic monitoring and 30 paired measurements in 32 patients after subsequent improvement or stabilization of clinical status. Correlation coefficient ranged from 0.37 to 0.98. Conclusions. Bland–Altman analysis is an alternative method for assessing the agreement between two methods of clinical measurement. According to our data, noninvasive technique – impedance cardiography – is a reliable method for hemodynamic monitoring in noncomplicated cases of acute myocardial infarction.
Background. Left ventricular remodeling is a complex pathologic process of progressive left ventricular dilatation, leading to dysfunction and heart failure in patients after myocardial infarction. Objective. To evaluate biochemical markers, reflecting cardiac remodeling process after first myocardial infarction and compare those markers with clinical characteristics of left ventricular remodeling. Material and methods. Brain natriuretic peptide, troponin I, creatine kinase, creatine kinase MB mass, lactate dehydrogenase levels were measured in 30 patients with acute myocardial infarction on days 1, 2, 3–7 . Brain natriuretic peptide was measured at 3 months, 6 months, and 2 years after myocardial infarction. Echocardiographic parameters of left ventricular remodeling were determined in acute phase (day 1–3), at 3 months, 6 months, and 2 years after MI. Results. In acute phase, brain natriuretic peptide level progressively increased according to worsening of left ventricular geometry: in normal left ventricle geometry group, brain natriuretic peptide level was 84.1 (58.7–121) pg/mL, in concentric remodeling group – 125 (69.2–165) pg/mL, in concentric hypertrophy group – 128 (74–368) pg/mL, and in eccentric hypertrophy group – 470 (459–494) pg/mL, P=0.02. Patients who had increased left ventricular end diastolic diameter index during 2-year period had higher brain natriuretic peptide level in the acute phase (584 (249–865) pg/mL vs. 120 (67–202) pg/mL, P=0.04) and also higher peak lactate dehydrogenase and troponin I levels. Conclusions. Brain natriuretic peptide level in acute phase of myocardial infarction is strongly associated with the markers of myocardial injury and related to left ventricular geometry changes and remodeling. Brain natriuretic peptide together with troponin I levels in acute phase of myocardial infarction might be useful in predicting subsequent cardiac function.
Aortic dissection is an acute lesion of the aortic wall accompanied by separation of the media due to rupture or intramural hematoma. The incidence rate of aortic dissection is 5 to 30 cases per million people a year. Acute aortic dissection is a highly lethal cardiovascular emergency with an incidence of 2000 new cases per year in the United States and 3000 in Europe. The mortality rate of aortic dissection is 3.2/100 000 per year. In case of sudden death of nonhospitalized patients, aortic dissection was proved in 1.5% of necropsy cases. Most of patients die within 48 hours after admission or 1.4% per each hour. The main clinical manifestations of aortic dissection are acute myocardial infarction, stroke, pulmonary embolism, acute heart failure, acute pancreatitis, mesenteries thrombosis, which mislead the physician. The main measure, which might reduce the mortality, is early diagnosis of aortic dissection. The standard diagnosis is based on clinical symptoms and verification by instrumental (imaging) methods. An alternative mean for diagnosis of aortic dissection might be the determination of concentration of smooth muscle myosin heavy chain protein in blood serum, the peak of which is found after 3 hours after the onset of pain. Normal value of smooth muscle myosin heavy chain protein concentration is 2.5 mg/L, while in case of aortic dissection it exceeds 22.4 mg/L. This diagnostic method has not been introduced in Lithuania yet.
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