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Biomedical subjects

G Kronik

Publications and source records attributed to G Kronik.

At least 37 records · Page 2Linked to original sources
PubMed1985

Two years' experience with the duromedics bileaflet heart valve prosthesis.

The new Duromedics Bileaflet Cardiac Valve prosthesis has a special moving hinge mechanism for its two leaflets to wash the critical articulation area and thus reduce thrombus formation. Between October 1983 and June 1985, we implanted 278 of these prostheses in 254 patients. We did 114 aortic valve replacements, 109 mitral valve replacements, 34 double valve replacements, and two tricuspid valve replacements. Nearly 20% of the patients had had previous cardiac procedures. The hospital mortality was 5.9%. Follow-up was started with 214 surviving Austrian patients, and up to the present time, we have a follow-up period of 1704 patient months. Five patients died late after the operation (3.5 per 100 patient years). We observed 10 valve-related complications in nine patients (7 per 100 patient years). There were three cases of prosthetic endocarditis (2.1 per 100 patient years), two paravalvular leaks, and four bleeding episodes (2.8 per 100 patient years). The mechanical hemolysis was minimal, and the postoperative hemoglobin value averaged 15 g%. The LDH increased from 230 IU to 307 in the aortic valve replacements, 406 in the mitral valve replacements, and 435 in the double valve replacements. Intraoperative pressure gradients and postoperative Doppler echocardiography showed good hemodynamic performance. We conclude that good clinical results and a low complication rate can be achieved with the Duromedics Valve.

Journal Article↗
PubMed1985

Functional tricuspid insufficiency: conservative or operative management.

Between 1978 and 1982 mitral valve replacement was performed in a total of 43 patients with mitral valve disease in the presence of functional tricuspid insufficiency (TI). The concomitant tricuspid valve regurgitation was treated conservatively in 17 patients, a Carpentier ring prosthesis was implanted in 9 patients. De Vega annuloplasty was performed in 13 patients and 4 times the valve was replaced with a Hancock bioprosthesis. The hospital mortality of 26% (11 patients) was high, due to the poor clinical condition of the patients. In a mean follow-up of 43.1 +/- 18,0 months, 20 patients could be restudied by clinical and echocardiographical investigation. Tricuspid insufficiency was found in all of the 9 patients who had been treated conservatively. Seven out of 11 patients operated showed no signs of TI, 3 had mild TI and 1 patient had severe TI. In the conservatively treated group, the preoperative mean pulmonary vascular resistance (PVR = 296 +/- 161 dynes x sex x cm-5), pulmonary artery pressure (PAP = 46.1 +/- 16.2 mmHg) and rise of right atrial V-wave (15.8 +/- 3.6 mmHg) were only slightly higher than n the operatively treated group (PVR - 274 +/- 146 dynes x sex x cm-5), PAP = 43.2 +/- 13.6 mmHg, V-wave = 18.5 +/- 6.4 mmHg) with no statistically significant difference. Preoperative hemodynamic findings in patients with and without TI a follow-up were also not significantly different. These results indicate that the recurrence of functional TI depends on the method of treatment, rather than preoperative increased PVR, PAP or V-wave rise.

Bioprosthesis↗
PubMed1985

[Significance of the stress test for the diagnosis of stenosis of the left main coronary artery. Distinctly different results in relation to the degree of stenosis].

Coronary anatomy and the results of treadmill exercise testing were compared in two partially overlapping groups of patients. In the first part of the study, treadmill tests of 29 patients with significant (greater than or equal to 50%) left main stenosis were compared to those of 40 patients each with proximal 1-, 2-, and 3-vessel disease, respectively. Two distinct subgroups were identified among the patients with greater than or equal to 50% left main stenosis: Of those with greater than or equal to 70% left main stenosis all had a positive (ST decreases greater than or equal to 0.1 mV) stress test, 79% had a markedly positive (ST decreases greater than or equal to 0.2 mV) test and this group had the lowest exercise capacity. In patients with only moderate left main stenosis (50-70%) ST-segment depression was significantly less and occurred significantly later than in patients with severe left main stenosis and 3-vessel disease. Patients with 1-, and 2-vessel disease could be clearly separated from patients with either severe left main stenosis or 3-vessel disease, but not from those with only moderate left main stenosis. In the second part of the study the coronary anatomy of 62 patients with a markedly positive stress test was analysed. In these patients left main stenosis, 3-, 2-, and 1-vessel disease was observed in 10%, 50%, 23% and 16%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1984

[Diagnosis and drug therapy in the postinfarct phase].

The main goal of all diagnostic procedures after myocardial infarction is the identification of high risk patients. Left ventricular pump function, the extent of coronary artery disease and serious arrhythmias have the strongest impact upon prognosis. Left ventricular pump function can be assessed by echocardiography and radionuclide ventriculography. This is of importance in patients with congestive heart failure to distinguish between a resectable aneurysm and diffusely impaired pump function. Routine application of these methods does not seem necessary since our ability to improve pump function is limited. The extent of coronary artery disease can not be assessed non-invasively. Ergometry does provide us, however, with clinically important data (angina?, ST-depression?, arrhythmia?, drop of blood pressure? etc.) some of which are also predictors of prognosis. Stress testing with low work loads (up to 75 W) should therefore be performed in all patients soon after the infarct on a routine basis. The standard 12-lead ECG is insufficient for the diagnosis of serious arrhythmias. Therefore a 24-hour ECG tape recording would be desirable in every patient, but it is particularly important in patients with poor left ventricular function or premature beats on the resting ECG, who are known to have a high probability of serious arrhythmias. Coronary arteriography is indicated, when the patient is severely symptomatic and when the non-invasive tests indicate that the patient is at high risk. Drug therapy of angina pectoris and arrhythmias after myocardial infarction is basically the same as in patients without a history of infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1984

[Changes in the left ventricular ejection fraction during exercise and in the thallium-201 perfusion after administration of dipyridamole in patients with coronary disease].

46 patients with coronary artery disease (at least 70% stenoses) were studied with thallium-201 imaging following dipyridamole (0.50 mg/kg bodyweight intravenously) with 4-hour control and by radionuclide ventriculography at rest and during symptom-limited bicycle exercise in supine position. 38 patients (83%) had positive thallium-201 findings with persistent defects in 18 and transient defects in 20 cases. Mean left ventricular ejection fraction (EF) fell during exercise from 56.1% +/- 13.3 to 50.2% +/- 14.5 (p less than 0.001). 43 patients (93%) showed an abnormal EF response to exercise (rise of less than 10% of the control EF during exercise). In 8 patients with false negative thallium-findings the EF did not change from rest to exercise (64.1% +/- 10.0 vs. 64.6% +/- 8.5), however, in the 20 patients with transient Tl-201 defects a significant fall of the EF was noted (60.8% +/- 9.1 vs. 49.8% +/- 10.9, p less than 0.001), in the 18 patients with persistent defects only a slight decrease of the EF was induced with exercise (47.3% +/- 14.0 vs. 44.2% +/- 16.1, p less than 0.02). Thus transient Tl-201 defects usually predict functional impairment of the left ventricle with exercise, persistent defects suggest impaired rest function with only minor further dysfunction during exercise. Compared with rest and exercise ECG in these patients, both radionuclide techniques showed a significantly higher sensitivity.

Adult↗
PubMed1984

Impact of thallium-201 imaging on clinical assessment and management of patients with chest pain.

The histories, rest, and exercise ECG results of 60 patients without myocardial infarction complaining of chest pain were submitted to 6 physicians (3 cardiologists and 3 noncardiologists) who were unaware of the angiographic findings. The physicians were requested to estimate the probability of coronary artery disease present in percentages and to assess the need for coronary angiography on a five-point scale (1 = definitely not indicated, 5 = definitely indicated). After obtaining the results of thallium-201 imaging following dipyridamole (0.50 mg/kg intravenously) administration, the physicians were again requested to estimate probability and need for angiography. In the 43 patients with coronary artery disease the judgment of probability was increased significantly after 201Tl from 75.6 +/- 20.2% to 82.9 +/- 23.2% (p less than 0.001) and the need for angiography from 4.3 +/- 0.9% to 4.5 +/- 0.9% (p less than 0.001). In the subgroup of patients with atypical angina the relative change in probability was higher than in other subgroups of patients with coronary artery disease. In the 17 patients with normal coronary arteries the probability estimation fell after 201Tl from 36.7 +/- 22.0% to 24.8 +/- 21.0% (p less than 0.001), the need for angiography was decreased from 2.7 +/- 1.1% to 2.2 +/- 1.2% (p less than 0.001). With the 201Tl information, cardiologists performed a better diagnostic differentiation of patients with and without coronary artery disease than noncardiologists. The study demonstrates the improvement of clinical diagnosis in patients with chest pain by thallium-201 imaging and confirms the favorable influence of the method on the management of the patients in terms of indications for coronary angiography.

Angiography↗
PubMed1984

Angiographic demonstration of tumor vascularity in left atrial myxoma: a case report.

We describe a 63-year-old woman with a large sessile left atrial myxoma and coexisting mitral valve stenosis and regurgitation. The diagnosis of a left atrial tumor was confirmed by echocardiography and coronary angiography. This case reveals the rare finding of tumor vascularity originating from both the right coronary artery and left circumflex artery.

Coronary Angiography↗
PubMed1984

Haemophilus parainfluenzae endocarditis on tricuspid valve.

After an episode of intermittent fever which lasted 45 days, endocarditis of the tricuspid valve was diagnosed using M-mode echocardiography in a 17-year-old female patient who had no history of drug abuse. After unsuccessful therapy with ampicillin, tetracycline and aminoglycosides, clinical improvement was achieved by treatment with temocillin.

Adolescent↗
PubMed1984

[Diagnosis of interatrial communications using contrast echocardiography].

M-mode contrast echocardiography with peripheral venous injections was performed in 73 patients with interatrial communications: 48 (group 1) had a hemodynamically significant atrial septal defect (ASD), 19 (group 2) had a patent foramen ovale (PFO) without clinical or oxymetric evidence of a shunt. The remaining 6 (group 3) had an interatrial communication in combination with severe additional congenital malformations predisposing to a right to left (R-L) shunt. Contrast studies were considered positive for a shunt lesion when at least five clearly recognizable contrast echoes appeared in the left heart following one injection. During quiet respiration positive contrast studies were obtained in 85% of all ASD patients (including all 10 with Eisenmenger's reaction and 31/38 [82%] uncomplicated cases); in 37% of the PFO cases (including 3/13 with normal right heart pressures), and in 53/73 (73%) of all patients with interatrial communications. The intensity of contrast shunting was variable in all groups. Opacification of the mitral funnel (which is typical for an atrial level shunt) was observed in 45 patients. In 8 patients with positive studies the few contrast echoes, that appeared in the left heart were first seen after they had left the mitral valve. Contrast injections into the pulmonary artery were performed in a control group of 29 patients. No contrast appeared in the left heart as expected. In 57 patients (39 ASD, 17 PFO, 1 group 3) contrast studies were also performed during the Valsalva maneuver. Valsalva provocation resulted in increased contrast shunting in 19, led to new mitral funnel opacification in 9 and improved the sensitivity of contrast echocardiography by 9 and 26% in ASD and PFO cases respectively. The intensity of contrast shunting was largely independent of the hemodynamic findings and was often variable upon subsequent injections in the same patient. Therefore contrast echocardiography is not helpful in predicting the L-R shunt or the pulmonary artery pressure and does not seem suited for follow-up studies. The differentiation between true contrast echoes in the left heart and artifacts, noise echoes, "overload", or incomplete mitral structures and the differentiation between interatrial and interventricular contrast shunting is usually easy. However the distinction between a hemodynamically significant ASD and pulmonary arteriovenous fistulas, certain venous anomalies or a patent foramen ovale may be difficult or even impossible by contrast echocardiographic criteria alone. Resting two-dimensional contrast echocardiograms were recorded in 57 patients including 34 with ASD, 18 with PFO and 5 from group 3.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Diagnosis of interatrial shunts using contrast echocardiography].

M-mode contrast echocardiography with peripheral venous injections was performed in 73 patients with interatrial communications: 48 (group 1) had a hemodynamically significant atrial septal defect (ASD), 19 (group 2) had a patent foramen ovale (PFO) without clinical or oxymetric evidence of a shunt. The remaining 6 (group 3) had an interatrial communication in combination with severe additional congenital malformations predisposing to a right to left (R-L) shunt. Contrast studies were considered positive for a shunt lesion when at least five clearly recognizable contrast echoes appeared in the left heart following one injection. During quiet respiration positive contrast studies were obtained in 85% of all ASD patients (including all 10 with Eisenmenger's reaction and 31/38 [82%] uncomplicated cases); in 37% of the PFO cases (including 3/13 with normal right heart pressures), and in 53/73 (73%) of all patients with interatrial communications. The intensity of contrast shunting was variable in all groups. Opacification of the mitral funnel (which is typical for an atrial level shunt) was observed in 45 patients. In 8 patients with positive studies the few contrast echoes, that appeared in the left heart were first seen after they had left the mitral valve. Contrast injections into the pulmonary artery were performed in a control group of 29 patients. No contrast appeared in the left heart as expected. In 57 patients (39 ASD, 17 PFO, 1 group 3) contrast studies were also performed during the Valsalva maneuver. Valsalva provocation resulted in increased contrast shunting in 19, led to new mitral funnel opacification in 9 and improved the sensitivity of contrast echocardiography by 9 and 26% in ASD and PFO cases respectively. The intensity of contrast shunting was largely independent of the hemodynamic findings and was often variable upon subsequent injections in the same patient. Therefore contrast echocardiography is not helpful in predicting the L-R shunt or the pulmonary artery pressure and does not seem suited for follow-up studies. The differentiation between true contrast echoes in the left heart and artifacts, noise echoes, "overload", or incomplete mitral structures and the differentiation between interatrial and interventricular contrast shunting is usually easy. However the distinction between a hemodynamically significant ASD and pulmonary arteriovenous fistulas, certain venous anomalies or a patent foramen ovale may be difficult or even impossible by contrast echocardiographic criteria alone. Resting two-dimensional contrast echocardiograms were recorded in 57 patients including 34 with ASD, 18 with PFO and 5 from group 3.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

[Reproducibility of repeated measurements using M-mode echocardiography, radionuclide ventriculoradiography and systolic time intervals].

The reproducibility of M-mode echocardiography, radionuclide ventriculography, and systolic time intervals (PEP/LVET) was studied in 16 patients with symmetrically contracting left ventricles and no signs of coronary heart disease. The values were determined four times in these 16 patients: twice each on day 1 and day 8 at an interval of 2-3 h. The mean EF and PEP/LVET values were nearly identical in all 4 repeat studies. There was a high correlation of echocardiographic and scintigraphic EF measurements (r between 0.90 and 0.96); the correlation between PEP/LVET and EF was considerably poorer (r ranging from -0.56 to -0.79). There was no difference in mean serial variabilities of EF for all repeated studies performed on the same day and on separate days for either echocardiography or radionuclide ventriculography. The mean variability of absolute EF for repeated studies was 2.9 +/- 2.4% for M-mode echocardiography and 3.4 +/- 2.4% for radionuclide ventriculography. To be attributed to nonrandom physiological alterations the absolute change in EF in an individual patient should be at least 8% for echocardiography and 9% for radionuclide ventriculography. The mean variabilities of PEP/LVET were different in studies performed on the same day and on separate days (0.03 +/- 0.02 vs 0.04 +/- 0.03, p less than 0.01). In 7 further patients the effect of dobutamine infusion was studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Diagnosis of interatrial communication with contrast echocardiography].

M-mode contrast echocardiography with peripheral venous injections was performed in 73 patients with interatrial communications: 48 with atrial septal defect, 19 with a patent foramen ovale, and six with complex congenital heart disease in addition to their atrial septal defect. During resting conditions a cross-over of echo-contrast from the right to the left atrium indicating a right to left shunt was observed in 41/48 (= 85%) of the atrial septal defect cases, including all with and 82% of those without Eisenmenger's reaction, in 7/19 (= 37%) with patent foramen ovale and in 83% of all examined patients. The echocardiographically detectable right to left shunt could often be increased or provoked by repeating injections during the Valsalva maneuver. Positive contrast studies either at rest or with Valsalva provocation were observed in 94% of the atrial septal defect group and 63% of the patients with patent foramen ovale. Two-dimensional contrast echocardiography was somewhat less sensitive in detecting right to left shunts, but allowed the demonstration of the left to right shunt in 79% of the patients with uncomplicated atrial septal defect. The left to right shunt was seen as a stream of contrast free left atrial blood entering the contrast filled right heart through the defect and causing a "wash out" phenomenon. When all available techniques were applied, either a right to left shunt (rest and/or Valsalva maneuver) or a left to right shunt was demonstrable in all cases of atrial septal defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiography↗
PubMed1983

Glycosylated hemoglobin as a long-term parameter in appraising the severity of hemolytic disease.

Reduced levels of glycosylated hemoglobins (GHb) have been found to be closely related to red cell survival. We therefore studied the relation of this parameter to the clinical applicability in patients with hemolytic disease (n = 20). During a 5-week period we repeatedly measured severity of anemia, i.e., hemoglobin (Hb), packed red cell volume (VPRC), and red blood cell count (RBC), as well as reticulocytosis and parameters of red cell destruction such as serum concentration of lactic dehydrogenase (LDH) and bilirubin together with GHb. There was a weak correlation between simultaneously measured GHb and RBC (r = 0.5, P = 0.02), but none was demonstrable between GHb and Hb, VPRC, reticulocyte counts, LDH, or bilirubin. A much closer correlation, however, was found between actual GHb levels and RBC determined 3-5 weeks previously (r = 0.72, P = 0.001), as well as Hb (r = 0.56, P = 0.015), VPRC (r = 0.57, P = 0.013), reticulocyte counts (r = -0.63, P = 0.006), LDH ( r = -0.53, P = 0.02), and serum bilirubin concentrations ( r = -0.55, P = 0.016). Ghb was also significantly decreased in patients with consistently low values of reticulocytes when red cell destruction was demonstrable. These results show that GHb is a measure of red cell destruction and restitution, and thus may be usefull for long-term monitoring of patients with hemolytic disease.

Adolescent↗
PubMed1983

The effect of iodine containing contrast medium on thyroid function of patients undergoing coronary angiography.

Application of large amounts of iodine in the form of amidotricoic acid (Urografin) in 20 patients undergoing coronary angiography led to an increase in serum thyroxine (T4, p less than 0.005), triiodothyronine (T3, p less than 0.005) and plasma thyrotropin (TSH) in the basal state (p less than 0.05) as well as after TRH-stimulation (p less than 0.05), but not of serum 3,3',5'-triiodothyronine (reverse-T3, rT3) three weeks after contrast medium administration. Although TRH induced TSH stimulation had been subnormal prior to contrast medium application in five patients, T4 as well as T3 remained within the normal range in all patients. Neither preexisting iodine excretion nor the amount of contrast medium applied were related with the observed hormonal changes. We conclude, that application of relatively small as well as large amounts of amidotricoic acid leads to an increase of peripheral thyroid hormone concentrations, paralleled by a rise in basal and stimulated TSH secretion. These changes may be interpreted as physiological adaptation to augmented iodine supply in an area of moderate iodine deficiency.

Adult↗
PubMed1983

Thallium-201 imaging after dipyridamole in patients with coronary multivessel disease.

In 60 patients with angiographically documented 2- or 3-vessel disease (at least 70%) thallium-201 images after dipyridamole (0.50 mg/kg bodyweight i.v.) and 4 h later were obtained. In 95% of the patients stress perfusion defects were found. In 48% of the cases scintigraphy correctly diagnosed the presence of multivessel disease, but in only 30% of the patients were all angiographically narrowed vessels detected. The reliability of the method was much higher in the detection of 'infarct stenoses' (96%) than of 'noninfarct stenoses' (46%). The regional sensitivity to assess stenoses of the left anterior descending artery (75%) and right coronary artery (73%) was greater than in stenoses of the left circumflex artery (37%). Thallium-201 scintigraphy after dipyridamole is a sensitive method for diagnosing the presence of coronary artery disease. The diagnostic value is severely limited however by the fact that coronary vasodilation may provoke perfusion abnormalities only in the most ischemic regions, whereas perfusion defects in other areas may not be detectable. Therefore this method does not allow the precise quantitation of all coronary stenoses in the majority of patients.

Adult↗
PubMed1983

[Diagnostic value of 201-thallium imaging following dipyridamole in patients with a normokinetic left ventricle].

In 100 patients with a normokinetic left ventricle 201-thallium imaging following administration of dipyridamole (0.50 mg/kg body wt. i.v.) showed a sensitivity of 67% (41/61) and a specificity of 95% (37/39) in diagnosing coronary artery disease. Exercise stress testing gave nearly equal sensitivity values (36/58 = 62%) with only slightly lower specificity (32/39 = 85%). The rate of true positive 201-thallium findings increased with the number of narrowed vessels (one vessel disease 50%, two vessel disease 63%, three vessel disease 94%); the extent of coronary artery disease was almost regularly underestimated with the scintigraphic method. Because of the low sensitivity a negative finding cannot exclude the presence of coronary artery disease, but the existence of three vessel disease can be considered improbable in patients in whom thallium scintigraphy findings are negative. Analysis following Bayes' theorem revealed the method to have a low diagnostic value in patients with either very low or high pretest probability for the disease; either a positive or a negative finding is of most use in a patient with low or average pretest probability of the disease (20-60%).

Coronary Disease↗
PubMed1982

Positive contrast echocardiography in patients with patent foramen ovale and normal right heart hemodynamics.

Peripheral M mode contrast echocardiograms were performed at rest and during the Valsalva maneuver in 11 patients with patent foramen ovale and normal right heart pressures documented by catheterization studies. Positive contrast studies (at least five clearly identifiable contrast echoes appearing in the left heart) were obtained in three patients (27 percent at rest) in six (54 percent) during the Valsalva maneuver and in seven patients (64 percent) either at rest or during the Valsalva maneuver. It is concluded that contrast echocardiography offers an opportunity to diagnose a patent foramen ovale noninvasively in patients with suspected paradoxical embolism or with questionable evidence of atrial septal defect. A positive study result does not specifically indicate heart disease since it occurs in healthy persons with patent foramen ovale, normal intracardiac pressures and no other abnormality.

Adolescent↗