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Biomedical subjects

T Linderer

Publications and source records attributed to T Linderer.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Detection of early reperfusion and prediction of left ventricular damage from the course of increased ST values in acute myocardial infarct with thrombolysis].

In 60 patients with acute myocardial infarction (pain < or = 4 h), we examined the value of ST segment monitoring in predicting early reperfusion, resulting left ventricular damage, and complications during hospitalization. Two criteria were determined by observation of the ST segment elevation during the first 4 h following initiation of thrombolysis. Early reperfusion was assessed by an early increase of the creatine phosphokinase (CK) with measurements taken in 15-min intervals. Cardiac catheterization was performed on days 11 +/- 5. According to the CK measurements, a reduction of the ST elevation > or = 50% within 1 h of serial ECG follow-up (ST criterion A) was the best indicator of early reperfusion (sensitivity 84%, specificity 80%, positive predictive value 93%, negative predictive value 67%). Simple comparison of the ST segment in the initial ECG and an ECG recorded 3 h later (ST criterion B) was less accurate according to the detection of early reperfusion (sensitivity 68%, specitivity 93%, positive predictive value 97%, negative predictive value 50%). However, contrary to ST criterion A, criterion B was useful in predicting subsequent left ventricular damage. Patients with a resolution of the initial ST elevation > or = 70%/3 h showed smaller regional wall motion abnormalities (dyssynergic area 21.3 +/- 20.3 vs 33.8 +/- 18.4, p < 0.01) and a better left ventricular ejection fraction (57.7 +/- 11.6 vs 50.2 +/- 12.6, p < 0.05). Patients with early reduction of the ST elevation following either criterion experienced fewer critical events (reinfarction, reischemia, death). In conclusion, the investigated criteria are useful in assessing reperfusion of the infarcted artery following thrombolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anistreplase↗
PubMed1992

Efficiency of a physician-operated mobile intensive care unit for prehospital thrombolysis in acute myocardial infarction.

The efficiency of an emergency medical system for routinely performed prehospital thrombolysis is evaluated for 1 of the 7 physician-staffed mobile intensive care units (MICU) in former West Berlin. During 19 consecutive months the MICU had 4,920 missions, and 1,226 patients had chest pain of presumed cardiac origin. The diagnosis at hospital discharge was acute myocardial infarction (AMI) in 406 patients and "interrupted" infarction in 11 patients (total 417). Correct on-scene electrocardiographic diagnosis of acute injury was made in 268 patients (64%) and was false-positive in 4 patients (1%). In 8%, present ST elevations were not recognized. In 27%, the electrocardiogram on scene was nondiagnostic (16% with no ST elevation, 11% with bundle branch block). Of all 417 patients with later hospital evidence of AMI, 317 (76%) were seen by the MICU physician within 4 hours, and 173 (41%) within the first hour from symptom onset. Two hundred three patients seen within 4 hours had diagnostic ST elevation on the scene, of whom 124 (61%) received prehospital thrombolysis (74 patients [36%] within the first hour). There was no prehospital death; hospital mortality was 6.3%. Because greater than 50% of all patients in the community, hospitalized because of AMI, made use of the MICU and 3/4 of them had called within 4 hours from symptom onset, a large proportion of all patients with AMI were candidates for the actually received prehospital thrombolysis.

Ambulances↗
PubMed1992

Effect on global and regional left ventricular functions by percutaneous transluminal coronary angioplasty in the chronic stage after myocardial infarction.

Data are reported on 145 consecutive patients with prior myocardial infarction who had successful percutaneous transluminal coronary angioplasty (PTCA) of the infarct-related artery (5 +/- 6 months after infarction), and left ventricular (LV) angiograms before PTCA and during follow-up (7 +/- 4 months). There was a significant long-term improvement in LV function, ejection fraction increased from 60 +/- 13% to 64 +/- 13% (p less than 0.001), and regional wall motion abnormalities decreased by 40%. Multivariate discriminant analysis identified reduced LV function and a high degree of stenosis before PTCA as predictors for improvement in LV function (ejection fraction less than 60%: ejection fraction from 48 +/- 9% to 57 +/- 14%, p less than 0.001; and stenosis greater than or equal to 90%: ejection fraction from 59 +/- 15% to 66 +/- 14%, p = 0.003). Restenosis greater than or equal to 90% in patients with initial stenosis less than 90% decreased ejection fraction from 59 +/- 16% to 51 +/- 14% (p less than 0.05). Other factors tested (treatment of infarction by thrombolysis, time between infarction and PTCA, and severity of angina pectoris) had no effect on long-term changes in LV function. It is concluded that successful elective PTCA of a high-grade stenosis in an infarct-related artery may improve LV ejection fraction and regional wall motion abnormalities, especially in patients with impaired LV function.

Adult↗
PubMed1992

[Is pre-hospital thrombolysis in acute myocardial infarct valuable as a routine measure?].

UNLABELLED: In 4920 consecutive missions of the mobile intensive care unit Klinikum Steglitz, 1226 patients (25%) had chest pain of presumed cardiac origin. In 272 patients (22%) an acute myocardial infarction (AMI) was diagnosed in the field. In four patients the diagnosis was wrong; 11 patients with proven coronary artery disease had significant ST-segment elevation, but did not develop AMI. In hospital, a total of 406 patients had evidence of AMI; 173 of these (41%) were seen by an emergency physician in the field already within the first hour after onset of symptoms. In 6%, diagnostic ST-elevation was not recognized by the emergency physician; 27% had non-diagnostic ECG changes (11% bundle-branch block). Prehospital thrombolysis within 4 h after symptom onset was performed in 126 of 205 patients (61%); 74 of these patients were seen by the emergency physician within the first hour. The main reason for exclusion was advanced age. Inclusion of older patients and also those with bundle-branch block could further increase the prehospital thrombolysis rate. CONCLUSION: With an effective emergency medical system a large proportion of all patients with AMI can correctly be identified and properly treated with a thrombolytic drug in the field. The time gain is considerable.

Aged↗
PubMed1990

Influence of catheter technology and adjuvant medication on acute complications in percutaneous coronary angioplasty.

We report on the complication rates in 660 consecutive coronary angioplasties (725 lesions) performed using four procedures that differed with respect to catheter technology and adjuvant medication. After the PTCA regimen in our laboratory had been changed from conventional steerable systems to the monorail technique, we observed a significant increase in the incidence of transient vessel occlusions from 2.6% to 7.7%, of permanent occlusions from 3.6% to 8.8%, and of intracoronary thrombus-formation from 2.6% to 5.5%. This was associated with the frequent observation of thrombotic material on the partially Teflon-coated guidewires. Coronary perfusion with urokinase (1,670-6,670 U/min) lead to a further increase in the complication rates (10.4%/10.3%/6.5%). Our present percutaneous transluminal coronary angioplasty (PTCA)-regimen (monorail technique with P.E.T. balloons, fully silicon-coated guidewires, no urokinase) shows an incidence of 3.8% for intermittent and recurrent coronary occlusions and 1.9% for permanent occlusions. Urokinase did not prevent intracoronary thrombus formation with the monorail technique. Furthermore, we suspect that in the case of PTCA-induced regional intimal dissection, fibrinolysis can prevent reestablishment of intima adherence to the vessel wall. Because five procedural deaths were observed in the 212 patients treated with i.c. urokinase as opposed to three deaths in the 448 procedures without urokinase, we feel that i.c. urokinase in PTCA is a potentially harmful regimen. We suggest that the monorail technique should be performed with fully silicon-coated guidewires and without urokinase.

Angioplasty, Balloon, Coronary↗
PubMed1990

Controversial indications. Rationale for thrombolysis: later than 4-6 h from symptom onset, and in patients with smaller myocardial infarctions. The ISAM Study Group.

To evaluate the effect of late reperfusion of an infarct-related coronary artery on left ventricular (LV) function in the month after myocardial infarction (MI), findings from 386 patients in the Intravenous Streptokinase in Acute Myocardial Infarction (ISAM) trial were studied. All patients had a late peaking in the creatine kinase-MB serum time-activity curve, suggesting absence of early reperfusion. Significantly better LV function associated with patency of the infarct artery at angiography 1 month after the acute event confirmed the beneficial effect of reperfusion even if achieved beyond the time window for myocardial salvage. Thrombolysis commenced later than 4-6 h after symptom onset will be of benefit as long at it reopens infarct arteries more often and earlier than occurs spontaneously or from anticoagulation. The value of the size of the sum of ST-segment elevation (sigma ST increases) on admission ECG was evaluated from the total ISAM study population. The relation between sigma ST increases and final infarct size as well as mortality risk was highly significant. However, weak correlations largely limit the value of sigma ST increases to predict the outcome in an individual patient. Thus, whatever the relative beneficial effect in patients with smaller or larger MI may be, it would be unwarranted to withhold thrombolytic therapy from patients with smaller sigma ST increases on admission ECG.

Aged↗
PubMed1990

[Favorable long-term prognosis following late recanalization of main branch occlusion of the left coronary artery].

A 52-year-old man presented with an acute anterior myocardial infarction due to total occlusion of the left main coronary artery. Three weeks later a successful recanalization was performed. At an early recoronarography the vessel was patent. Initially existing severe congestive heart failure (NYHA class IV) improved to NYHA class II over 6 months. Three years later the patient is almost without complaints and, at echocardiography, left-ventricular enlargement was clearly declining.

Angioplasty, Balloon, Coronary↗
PubMed1990

[Acute complications in coronary angioplasty: dependence on catheter material and adjuvant medication].

We report on the complication rates in 660 consecutive coronary angioplasties (725 lesions) performed using four procedures that differed with respect to catheter technology and adjuvant medication. After the PTCA regimen in our laboratory had been changed from conventional steerable systems to the monorail-technique, we observed an increase in the incidence of intermittent and recurrent vessel occlusions from 2.6% to 7.7%, of permanent occlusions from 3.6% to 8.8%, and of intracoronary thrombus-formation from 2.6% to 5.5%. This was associated with the frequent observation of thrombotic material on the guide wires. Coronary perfusion with urokinase (1670-6670 U/min) lead to a further increase in the complication rates (10.4%/10.3%/6.5%). Our present PTCA-regimen (monorail-technique with PET balloons, silicon-coated guide wires, no urokinase) shows an incidence of 3.8% for intermittent and recurrent coronary occlusions, and of 1.9% for permanent occlusions. We suspect that in case of PTCA-induced regional intimal dissection, fibrinolysis prevents reestablishment of intima-adherence to the vessel wall. We conclude that i.c. urokinase in PTCA is a potentially harmful regimen and that the monorail-technique should be performed with silicon-coated guide wires.

Angioplasty, Balloon, Coronary↗
PubMed1989

Impact of late coronary artery reperfusion on left ventricular function one month after acute myocardial infarction (results from the ISAM study).

To evaluate the impact of late reperfusion of an infarct-related coronary artery on left ventricular (LV) function in the month after myocardial infarction, findings from 368 patients in the Intravenous Streptokinase in Myocardial Infarction study are presented. All patients had a late peaking in the creatine kinase-MB serum time-activity curve, suggesting absence of early reperfusion. Contrast angiography was performed 1 month after the acute event. The infarct-related coronary artery was patent in 74 of 116 (64%) streptokinase-treated patients and 141 of 252 (56%) patients treated with anticoagulant therapy (placebo group). In all baseline variables, including the actually developed enzymatic and electrocardiographic infarct sizes, there were no differences between the patent- or occluded-artery groups. A patent infarct artery 1 month after infarction was associated with significantly better LV function regardless of the vessel involved and whether or not patients had been treated with streptokinase. Ejection fraction in patients with patent versus occluded artery was 56 +/- 13 versus 50 +/- 14 (p less than 0.0005). Most benefit was noted in patients in whom the proximal left anterior descending coronary artery was affected: ejection fraction was 52 +/- 14 versus 36 +/- 12% (p less than 0.0005). Our data confirm that restoration of adequate flow through an infarct-related coronary artery beyond the time window for actual salvage of ischemic myocardium has a definite beneficial effect on LV function.

Aged↗
PubMed1989

[Circadian variation in the incidence of myocardial infarction. New perceptions about the mechanisms of acute coronary disease].

The time of acute myocardial infarction (MI) was determined from the onset of symptoms and an analysis made of the time-activity course of the plasma CK-MB isoenzyme in 1741 patients of the prospective multicentre ISAM study (much greater than Intravenous Streptokinase in Acute Myocardial Infarction much less than). The occurrence of MI had a circadian variation with a marked peak between 6 a.m. and 12 noon compared with other periods during the day (P less than 0.001). Between 8 and 9 a.m., the period of highest incidence, the number of MIs was about four times higher than between midnight and 1 am (the period of lowest incidence). There was a good correlation between the clinical and enzymatic criteria for onset of MI (r = 0.95; P less than 0.001). A similar circadian pattern was obtained independent of site of MI, age and sex of patients, as well as severity and extent of the coronary heart disease. The temporal relationship between increased incidence of acute coronary heart disease (MI, sudden cardiac death, symptomatic or silent myocardial ischaemia) in the morning and a rise in platelet aggregation in the morning may point to a causal relationship.

Adolescent↗
PubMed1989

Increased morning incidence of myocardial infarction in the ISAM Study: absence with prior beta-adrenergic blockade. ISAM Study Group.

The time of acute myocardial infarction was determined in all 1,741 patients of the ISAM (Intravenous Streptokinase in Acute Myocardial Infarction) Study, based on onset of clinical symptoms and evaluation of plasma CK-MB enzyme time-activity curves. The incidence of myocardial infarction was markedly increased between 6:00 AM and 12:00 noon compared with other times of day (p less than 0.001). Myocardial infarction occurred 3.8 times more frequently between 8:00 and 9:00 AM (hour of maximum incidence) than between 12:00 midnight and 1:00 AM (hour of minimum incidence). Time of myocardial infarction based on clinical and enzymatic methods correlated well (r = 0.95). Patients with higher or lower left ventricular ejection fraction, higher or lower degree of wall motion abnormalities and residual stenosis of the coronary arteries, and one-, two-, or three-vessel disease exhibited a similar circadian pattern, suggesting that the morning is a risk period for patients with mild as well as severe coronary artery disease. Only the group of patients receiving beta-adrenergic blocking therapy before the event did not show an increased morning incidence of myocardial infarction. This observation may contribute to an understanding of the mechanisms by which beta-blockers reduce the incidence of myocardial infarction. Further investigation of physiologic changes occurring during the morning period of increased risk of myocardial infarction may lead to better understanding of the disorder. Design and timing of cardioprotective medication may play a crucial role in improving prevention of acute myocardial infarction.

Adrenergic beta-Antagonists↗
PubMed1989

[Balloon valvuloplasty of calcified aortic stenosis is a realistic alternative to surgery: clinical and invasive results 17 months following the 1st or 2d dilatation].

Aortic balloon valvuloplasty was performed in 33 elderly patients (age 60-84, mean 74 years). In six cases, repeat-valvuloplasty was performed six months later. Mean follow-up so far has been 17 months (10-24 months). Follow-up included 23 invasive controls and repeat Doppler-echocardiographic estimation of valve gradient in all patients. At valvuloplasty, peak aortic gradient was reduced from 84 +/- 27 mm Hg to 40 +/- 18 mm Hg, valve area was increased from 0.39 +/- 0.11 cm2 to 0.74 +/- 0.16 cm2. Immediately after valvuloplasty, 76% of the patients were asymptomatic or significantly improved. At follow-up, 10 patients died and 12 patients underwent surgical valve replacement. Only seven patients are still improved or asymptomatic after 1st or 2nd valvuloplasty. Invasive control six to nine months after the 1st valvuloplasty showed satisfactory results for valve gradient and valve area in only one patient. At repeat-valvuloplasty, a mean valve gradient of 29.6 +/- 12.5 mm Hg was achieved. All patients with repeat-valvuloplasty again had invasive control after six months; peak gradient then was 56 +/- 17 mm Hg. Balloon valvuloplasty of acquired aortic valve stenosis is a palliative procedure with a high restenosis-rate. At the most, aortic valve area is doubled. In our opinion, it is only indicated in patients with an unacceptable high surgical risk. Today, old age alone is no contraindication to surgical valve replacement.

Aged↗
PubMed1987

A prospective placebo-controlled double-blind multicenter trial of intravenous streptokinase in acute myocardial infarction (ISAM): long-term mortality and morbidity.

Long-term mortality and morbidity of 1,741 patients with acute myocardial infarction, treated with intravenous streptokinase (1.5 million IU/h) or placebo, was assessed in a double-blind placebo-controlled trial (ISAM). At the 7 month follow-up, 94 (10.9%) of the 859 patients in the streptokinase group and 98 (11.1%) of the 882 patients in the placebo group had died; at an average follow-up of 21 months, 14.4% of the streptokinase group and 16.1% of the placebo group had died. The differences were not statistically significant. Long-term mortality was slightly higher in patients with anterior myocardial infarction and streptokinase treatment (20.1 versus 18.4%) and lower in patients with inferior myocardial infarction (10.2 versus 14.2%). Patients with previous myocardial infarction had a higher long-term mortality rate with streptokinase (34.9 versus 21.5% with placebo, p = 0.03). At 7 months, there were significantly more cases of reinfarction in the streptokinase group (7.2 versus 4.5%, p = 0.02). It is concluded that despite a significant limitation of infarct size by intravenous streptokinase, long-term mortality is only slightly reduced and reinfarction is significantly more frequent. Both findings suggest the need for complementary therapy such as revascularization procedures after thrombolysis.

Clinical Trials as Topic↗
PubMed1985

Follow-up after coronary arterial reperfusion with intravenous streptokinase in relation to residual myocardial infarct artery narrowings.

Short- and long-term changes in residual stenosis of the myocardial infarct-related coronary arteries in patients with successful reperfusion by intravenous streptokinase have not been determined until now. In 15 patients the residual diameter stenosis decreased significantly from 62 +/- 9% after 24 hours to 55 +/- 13% in the fourth week (p less than 0.005). Quantitative angiographic analyses in 61 patients with patent infarct-related coronary arteries in the fourth week revealed a mean diameter stenosis of 61 +/- 13%. The patients were followed up 34 +/- 10 months. Sixteen had elective coronary artery bypass surgery or percutaneous transluminal coronary angioplasty (PTCA). Eighteen without coronary artery bypass surgery or PTCA had undergone repeat angiography after 26 +/- 9 months. Twenty-five (41%) have had a residual diameter stenosis greater than 65% in the fourth week. A stenosis greater than 65% was found in: 4 of 5 patients with late reinfarction; 3 of 7 with 1-vessel coronary artery disease and persistent angina, compared with none of 11 with a stenosis less than 65%; 6 of 7, whose silent reocclusion had been found at long-term follow-up compared with 1 of 9 with a residual stenosis less than 65%. In 8 patients with persistent patency of the infarct artery, the stenosis had decreased significantly from 55 +/- 6% to 36 +/- 12% (p less than 0.005). Correspondingly, there was a significant improvement in the infarct-related left ventricular wall motion disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1983

Intravenous short-term infusion of streptokinase in acute myocardial infarction.

Short-term i.v. infusion of streptokinase was performed in 93 patients within 6 hours after the onset of acute myocardial infarction. Twenty-six patients underwent angiography in the acute phase (group A) and 52 underwent angiography in the fourth week only (group B); 15 patients had no angiography. Seven patients died during the hospital stay and six suffered nonfatal reinfarctions. There were no bleeding complications. In 11 of 21 group A patients, occluded coronary arteries were opened within 1 hour after the streptokinase infusion was started. In 84% of groups A and B, the infarct-related coronary artery was patent in the fourth week. In 75% of the patent arteries, the residual luminal diameter stenosis was less than 70%. According to serial serum CK-MB curves, recanalization was achieved mostly within 1-2 hours. Myocardial salvage was indicated by improvement in local contraction disorders in the recanalized group A patients and by the significant relationship between infarct size and time from symptom onset to treatment in group B. These data suggest that a high-dose, short-term, i.v. infusion of streptokinase is a safe and efficient method of restoring coronary blood flow. Expeditious initiation of i.v. streptokinase infusion is a critical determinant for early recanalization and salvage of myocardium. Patients with thrombotically subtotal occlusion probably receive the most benefit. Evaluation of the true impact on survival and myocardial function will require controlled clinical trials.

Adult↗
PubMed1983

Influence of atrial systole on the Frank-Starling relation and the end-diastolic pressure-diameter relation of the left ventricle.

The influence of atrial systole on the left ventricular function curve (stroke volume vs end-diastolic pressure or end-diastolic diameter) and on the left ventricular end-diastolic pressure diameter relation was studied in nine anesthetized, open-chest dogs whose atrioventricular (AV) node had been completely blocked. Measurements were made during volume loading with the pericardium closed and opened and during alternate AV sequential pacing (to permit atrial contribution to ventricular filling) and AV simultaneous pacing (to prevent atrial contribution). When the pericardium was closed, withdrawal of the atrial contribution shifted the stroke-volume end-diastolic pressure relation downward, but did not shift the stroke volume-end-diastolic diameter relation, i.e., it reduced stroke volume for a given end-diastolic pressure according to a reduction in end-diastolic volume. The downward shift of the stroke volume-end-diastolic pressure relation was caused by an upward shift of the end-diastolic pressure-diameter relation, which, for a given end-diastolic pressure, resulted in a smaller end-diastolic diameter and, thus, in a smaller stroke volume. The reason for the upward shift in the end-diastolic pressure-diameter relation was that the atrium remained full and thus increased pericardial pressure by increasing pericardial volume. Opening the pericardium shifted the end-diastolic pressure-diameter relation downward and to the right, shifted the stroke volume-end-diastolic diameter relation upward and abolished the effect of withdrawal of the atrial contribution on these curves. We conclude that in the presence of an intact pericardium, atrial systole shifts the stroke volume-end-diastolic pressure relation because it shifts the end-diastolic pressure-diameter relation and it improves left ventricular performance by increasing preload.

Animals↗