Biomedical subjects

M Pfisterer

Publications and source records attributed to M Pfisterer.

At least 55 records · Page 3Linked to original sources

PubMed1994

Aortic valve replacement in elderly patients with aortic stenosis.

OBJECTIVE: To assess the risk of aortic valve replacement and long-term follow-up in elderly patients with dominant aortic stenosis. DESIGN: Retrospective analysis of patients who had aortic valve replacement over a 10 year period and were routinely seen in an outpatient clinic. SETTING: University hospital. PATIENTS: 93 patients aged > or = 60 and 47 patients > or = 70 years with symptomatic aortic stenosis undergoing aortic valve replacement. MAIN OUTCOME MEASURES: Early and late mortality in different age groups. Influence of preoperative signs and symptoms on overall outcome. RESULTS: The proportion of patients older than 70 years increased from 11% in 1978 to 54% in 1986. Perioperative mortality was 3.6% and mortality after 2 and 5 years was 9% and 13% respectively. Survival was similar (85% and 83%, respectively) in patients aged 60-69 years (group 1, n = 93, mean age 64.5 (2.7) and patients aged > or = 70 years (group 2, n = 47, mean age 72.6 (2.5)). Additional coronary artery disease and coronary bypass grafting did not significantly affect survival. The cardiothoracic ratio was inversely related to survival (Cox regression, p < 0.05). Preoperative symptoms (syncope, angina pectoris, and dyspnoea) were similar in both patient groups. After a mean (SD) follow up of 51 (33) months 96% of surviving patients were in NYHA functional class I or II with no difference between the two age groups. Similarly, the cardiothoracic ratio and Sokolow index decreased to near normal values in both age groups. CONCLUSION: The risk of aortic valve replacement in patients with dominant aortic stenosis is low and not significantly influenced by age. Therefore replacement may be performed without increased risk in elderly patients and with a good long-term outcome.

Age Factors↗

PubMed1994

Diminished vascular response to inhibition of endothelium-derived nitric oxide and enhanced vasoconstriction to exogenously administered endothelin-1 in clinically healthy smokers.

BACKGROUND: Smoking is a major risk factor for the development of atherosclerosis. Because endothelial dysfunction may be a marker for future atherosclerosis, we investigated the effects of smoking on endothelium-dependent control of vascular tone. METHODS AND RESULTS: The effects of brachial arterial infusions of NG-monomethyl-L-arginine (L-NMMA), a nitric oxide synthesis inhibitor; sodium nitroprusside; endothelin-1; and norepinephrine on forearm blood flow (strain-gauge plethysmography) were compared in 29 long-term smokers and 16 nonsmokers. The acute effects of smoking on systemic hemodynamics, plasma catecholamines, and forearm vascular responses to these compounds were investigated in smokers only. Smokers did not differ from nonsmokers (n = 16) regarding the vascular effects of sodium nitroprusside (n = 13) or vasoconstriction due to norepinephrine and endothelin-1 (n = 16). Low-dose endothelin-1-induced vasodilation, believed to reflect endothelial prostacyclin or nitric oxide release, was absent in smokers (n = 16), and their increase of forearm vascular resistance (FVR) after L-NMMA (n = 13) was impaired (35.6 +/- 27.9% versus 118.8 +/- 43.2%, P < .001). Short-term smoking (n = 11) increased blood pressure, heart rate, and plasma epinephrine concentrations (P < .05 or less); enhanced endothelin-1-induced vasoconstriction (delta FVR, 457 +/- 192% versus 254 +/- 143%, P < .01); and decreased norepinephrine-induced vasoconstriction (P < .05), but had no effect on the other interventions. CONCLUSIONS: Long-term smoking is associated with a diminished nitric oxide-dependent component of basal vascular tone and an impaired endothelium-dependent vasodilator response to low-dose endothelin-1 and short-term smoking enhances endothelin-1-induced vasoconstriction. Impaired endothelial control of vascular tone might reflect impairment of normal antiatherosclerotic endothelial functions in smokers, but the relevance of smoking-induced enhancement of endothelin-1 vasoconstriction remains to be determined.

Adult↗

PubMed1994

A comparison of internal mammary artery and saphenous vein grafts after coronary artery bypass surgery. No difference in 1-year occlusion rates and clinical outcome. CABADAS Research Group of the Interuniversity Cardiology Institute of The Netherlands.

BACKGROUND: Superior patency rates for internal mammary artery (IMA) grafts compared with vein coronary bypass grafts have been demonstrated by retrospective studies. This difference may have been affected by selection bias of patients and coronary arteries for IMA grafting. METHODS AND RESULTS: To estimate the difference between IMA and vein grafts, we analyzed graft patency data of 912 patients who entered a randomized clinical drug trial. In this trial, 494 patients received both IMA and vein grafts (group 1) and 418 only vein grafts (group 2). Occlusion rates of IMA grafts and IMA plus vein grafts in group 1 were compared with those of vein grafts in group 2. Multivariate analysis was used to compare occlusion rates of IMA and vein grafts while other variables related to graft patency were controlled for. In addition, 1-year clinical outcome was assessed by the incidence of myocardial infarction, thrombosis, major bleeding, and death. Occlusion rates of distal anastomoses in group 1 versus group 2 were 5.4% (IMA grafts) versus 12.7% (vein grafts) (P < .0001) and 10.4% (IMA plus vein grafts) versus 12.7% (vein grafts) (P = .14). There was no difference in adjusted risk of occlusion between IMA grafts and vein grafts (P = .089). Type and location of distal anastomosis and lumen diameter of the grafted coronary artery were shown to be predictors of occlusion. Clinical events occurred in 17.8% (group 1) and 16.0% (group 2) of patients (P = .53). CONCLUSIONS: The observed difference in 1-year occlusion rates between IMA and vein grafts can be explained by a maldistribution of graft characteristics by selection of coronary arteries for IMA grafting rather than being ascribed to graft material. One-year clinical outcome is not improved by IMA grafting.

Aged↗

PubMed1994

Mortality within 24 hours of thrombolysis for myocardial infarction. The importance of early reperfusion. The GUSTO Investigators, Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries.

BACKGROUND: A paradoxical increased risk of death has been reported during the first 24 hours after thrombolysis for myocardial infarction. The mechanism of this phenomenon is not known, nor is its relation to the success or failure of reperfusion. The present study was a prospectively designed analysis of deaths occurring within the first 24 hours in the GUSTO trial. METHODS AND RESULTS: There were 41,021 patients enrolled in GUSTO, a randomized comparison of streptokinase with intravenous or subcutaneous heparin, accelerated tissue-type plasminogen activator (TPA), and combination of streptokinase and TPA. An angiographic mechanistic substudy examined reperfusion (using the TIMI flow grading criteria) 90 minutes after the assigned thrombolytic regimen was begun in 1567 patients. There were 1125 deaths (2.8%) within 24 hours ("early deaths") and 1726 additional deaths (4.2%) after 24 hours but within 30 days ("later deaths"). At the time of presentation, the most potent predictors of early death were hypotension and sinus tachycardia. In a multiple logistic regression model, lower systolic blood pressure, shorter height, higher heart rate, and the absence of prior smoking distinguished early death from later death. Reinfarction occurred in 26 patients (2.4%), shock in 572 patients (52%), atrioventricular block in 308 patients (28%), and tamponade in 106 patients (10%) dying early compared with 262 (15%), 788 (46%), 396 (23%), and 74 (4%) respective patients dying later. There were no differences in early mortality among the thrombolytic regimens for the first 6 hours after randomization. By 24 hours, however, mortality was 2.89% for streptokinase recipients, 2.84% for combination therapy recipients, and 2.36% for accelerated TPA recipients (P = .005). There was little difference among patients with differing flow grades in the infarct artery during the first 4 hours, although mortality was 2.35% for patients with flow grade 0 or 1, 2.92% for patients with flow grade 2, and 0.89% for patients with flow grade 3. CONCLUSIONS: Even with aggressive management regimens, mortality within the first 24 hours accounted for a large proportion of postthrombolytic deaths. Patients dying early were more likely to present with pump failure than were those dying later and were more likely to diet of events related to left ventricular dysfunction, although cardiac tamponade also accounted for a significant minority of these deaths. Thus, the severity of the clinical presentation rather than the underlying risk factors predicts early mortality. Based on the angiographic substudy data, it appears that rather than hastening early mortality, successful restoration of complete antegrade flow in the infarct-related artery protects against early death.

Aged↗

PubMed1993

Silent ischemia after percutaneous transluminal coronary angioplasty: incidence and prognostic significance.

OBJECTIVES: The objective of this observational study was to assess the incidence and prognostic significance of silent ischemia after percutaneous transluminal coronary angioplasty. BACKGROUND: Apart from coronary angioplasty, prognosis of patients with silent ischemia is similar to that of patients with angina pectoris. However, similar data concerning silent ischemia associated with restenosis after coronary angioplasty are missing. METHODS: A consecutive series of 490 patients was investigated for asymptomatic ischemia on thallium-201 scintigraphy 6 months after successful coronary angioplasty. Repeat angiography was performed in a subgroup of patients with ischemia and repeat angioplasty was performed when clinically indicated. Patients were followed up for 2.2 +/- 0.8 years for cardiac events. RESULTS: Six months after coronary angioplasty, ischemia was present in 112 (28%) of 405 patients, and 60% of these 112 were asymptomatic. Ischemia was associated with significant stenosis in 97%; in contrast, results of exercise electrocardiography were negative in 74% of patients with scintigraphic ischemia and angiographic restenosis. The degree of restenosis was similar in patients with symptomatic or silent ischemia (80 +/- 16% vs. 81 +/- 21%). The long-term prognosis of patients with silent ischemia was remarkably similar to that of symptomatic patients. A worse outcome of symptomatic patients was found only if repeat coronary angioplasty for restenosis was considered a separate event (p < 0.01). Silent and symptomatic ischemia predicted an increased risk for recurrent ischemic events but not for death. CONCLUSIONS: Thus, absence of symptoms and negative findings on an exercise electrocardiogram may not reflect a good angioplasty result. In addition, silent ischemia due to restenosis after coronary angioplasty has a significant prognostic importance for recurrent symptomatic ischemic events that may be reduced by repeat angioplasty.

Aged↗

PubMed1993

Prevention of one-year vein-graft occlusion after aortocoronary-bypass surgery: a comparison of low-dose aspirin, low-dose aspirin plus dipyridamole, and oral anticoagulants. The CABADAS Research Group of the Interuniversity Cardiology Institute of The Netherlands.

Aspirin, alone or in combination with dipyridamole, is known to prevent occlusion of aortocoronary vein grafts. The benefit of dipyridamole in addition to aspirin remains controversial, and the efficacy and safety of oral anticoagulants for prevention of vein-graft occlusion have not been established. We assessed one-year angiographic vein-graft patency after aortocoronary-bypass surgery in 948 patients assigned to receive aspirin, aspirin plus dipyridamole, or oral anticoagulants in a prospective, randomised trial. The design was double-blind and placebo-controlled for the aspirin groups, but open for oral anticoagulant treatment. Dipyridamole (5 mg/kg per 24 h intravenously for 28 h, followed by 200 mg twice daily) and oral anticoagulants (desired prothrombin time range 2.8-4.8 international normalised ratio) were started before surgery, and aspirin (50 mg per day) was started after surgery. Clinical outcome was assessed by the incidence of myocardial infarction, thrombosis, major bleeding, or death. Occlusion rate of distal anastomoses was 11% in the aspirin plus dipyridamole group versus 15% in the aspirin group (relative risk 0.76, 95% CI 0.54-1.05) and 13% in the oral anticoagulants group. Clinical events occurred in 20.3% of patients receiving aspirin plus dipyridamole compared with 13.9% of the aspirin group (relative risk 1.46, 95% CI 1.02-2.08) and 16.9% of the oral anticoagulants group. Our data provide no convincing evidence that addition of dipyridamole to 50 mg aspirin per day improves aortocoronary vein-graft patency. Moreover, there is evidence that the combination increases the overall clinical-event rate. Compared with aspirin, oral anticoagulants provided no benefit.

Acenocoumarol↗

PubMed1993

[Long-term effect of amiodarone therapy following myocardial infarct in patients with complex ventricular arrhythmias].

In the BASIS study, an improvement in 1 year survival of patients with asymptomatic complex ventricular arrhythmias with low-dose amiodarone was shown in comparison with an untreated control group. To assess whether this beneficial effect would last for a longer follow-up despite discontinuation of amiodarone therapy after one year, we assessed long-term survival and mode of death in the 91 survivors of the first year in the amiodarone treatment group and the 99 survivors in the control group by phone calls to private physicians, patients and hospitals. During a median follow-up of 72 (55-125) months, 184/193 patients (95%) could be reached. Causes of death during the follow-up were sudden (6 vs 14), non-sudden cardiac (8 vs 9), non cardiac (5 vs 9) and unknown (7 vs 6) in patients initially treated with amiodarone versus the control group respectively. The probability of death after 84 months was 30% in the amiodarone group and 45% in the control group, and was significantly lower in amiodarone treated patients with respect to all deaths (p = 0.024) as well as cardiac deaths (p = 0.027). This mortality reduction was only due to amiodarone treatment during the first year after the index infarction, whereas the survival curves did not differ significantly during the late follow-up. Thus, the risk of cardiac death is low after the first year after myocardial infarction and may not justify continued antiarrhythmic therapy in patients with initially complex asymptomatic ventricular arrhythmias.

Aged↗

PubMed1993

[Risk of cardiological interventions].

The risk of cardiac interventions has to be assessed in relation to the possible benefit and in comparison to the natural history and to alternative interventions. The relationship between complications (mortality, morbidity) and age, severity of the disease, gender and technique on one hand, and between risk of the intervention versus risk of uninfluenced natural history on the other, are discussed. Diagnostic, therapeutic and prophylactic interventions are presented separately; the benefit needs to be defined differently for each: diagnostic accuracy or symptom relief, improved quality of life and survival, and prolonged life respectively. Finally, it is stressed that the choice of an intervention is not only dependent on the determinants of risk, but also on the availability of a certain method, operator experience, cost and, last but not least, patient preference.

Adult↗

PubMed1992

Beneficial effect of amiodarone on cardiac mortality in patients with asymptomatic complex ventricular arrhythmias after acute myocardial infarction and preserved but not impaired left ventricular function.

To determine whether the beneficial effect of low-dose amiodarone on survival in patients with complex ventricular arrhythmias after myocardial infarction was dependent on left ventricular (LV) function, results of the Basel Antiarrhythmic Study of Infarct Survival were analyzed. Two hundred twelve patients after acute myocardial infarction with asymptomatic complex arrhythmias were randomly assigned to receive amiodarone 200 mg/day or to a control group and followed up for 1 year. Results of mortality and arrhythmic events were related to baseline radionuclide LV ejection fraction. With preserved (greater than or equal to 40%) LV ejection fraction, there was a significantly lower 1-year cardiac mortality in patients treated with amiodarone (1 of 68 or 1.5%) versus control subjects (5 of 56 or 8.9%; p less than 0.03). This was not the case for patients with LV ejection fraction less than 40%. Similarly, arrhythmic events were significantly reduced only in patients with preserved LV function. These results suggest an interaction between the effects of amiodarone on survival and LV dysfunction in patients after acute myocardial infarction. Because of 2 other small studies with similar results, this finding may be of clinical relevance and should be addressed in ongoing and future research with this drug.

Aged↗

PubMed1992

[Is it justifiable today to perform thrombolysis in only one fifth of the patients with myocardial infarct?].

The one year mortality data of 231 patients entering the hospital with acute myocardial infarction who did or did not undergo thrombolysis are presented. 49 patients (21.2%) received thrombolytic therapy. 31% were excluded from thrombolytic therapy because of age over 70 years, 29% because of the time lag since onset of symptoms (over 6 hours), 61% because of absent ECG criteria and 32% because of other contraindications. The one year mortality rate was significantly lower in patients undergoing thrombolysis (8.2%) versus patients without thrombolysis (20.3%, p less than 0.05). Mortality in patients without thrombolysis and age greater than 70 years was 23.6%, in patients with late entry 20.1%, in those excluded from thrombolytic therapy with missing ECG elevations 17.9% and in patients with contraindications 28%. If thrombolytic therapy was withheld due to age greater than 70 years or late entry only, mortality was high (33.3% and 38.5% respectively; p less than 0.02 versus lysis). This was not true for patients without significant ST elevation: to the contrary 12 of 42 patients without lysis (28.6%; p less than 0.02 versus lysed patients) and greater than or equal to 2 mm ST elevation irrespective of other exclusion criteria died. Since mortality in patients over 70 years of age or entering the hospital more than 6 hours after onset is of such magnitude (especially if there are ECG signs of ongoing ischemia), the risk-benefit ratio should be considered individually to ensure that these high-risk patients are not excluded a priori from thrombolytic therapy.

Adult↗

PubMed1992

Exercise-induced ST depression and ST/heart rate index to predict triple-vessel or left main coronary disease: a multicenter analysis.

The aim of this investigation was to determine the difference in accuracy between two frequently published noninvasive indicators of severity of coronary artery disease (exercise-induced ST segment depression and heart rate-adjusted ST depression [ST/HR index]). The study was designed as a survey of consecutive patients undergoing exercise electrocardiography and coronary angiography. There were a total of 2,270 patients without prior myocardial infarction or cardiac valvular disease referred for angiography from eight institutions in three countries; 401 of these patients had triple-vessel or left main coronary artery disease. The sensitivities of ST depression and ST/HR index in detecting triple-vessel or left main coronary artery disease were, respectively, 75% and 78% (p = 0.08) at cut point values where their specificities were equal (64%). This small increase in the accuracy of the ST/HR index was evident only at peak exercise heart rates below the median value of 132 beats/min, where the sensitivities of ST depression and ST/HR index were 73% and 76% (p = 0.03), respectively, at cut point values corresponding to a specificity of 60%. These results were consistent at all eight participating institutions. The increase in accuracy achieved by dividing exercise-induced ST depression by heart rate is small and confined exclusively to a low exercise heart rate. This lack of superiority cannot be generalized to all methods of heart rate adjustment.

Bias↗

PubMed1992

Effect of early intravenous heparin on coronary patency, infarct size, and bleeding complications after alteplase thrombolysis: results of a randomised double blind European Cooperative Study Group trial.

OBJECTIVE: To determine whether concomitant treatment with intravenous heparin affects coronary patency and outcome in patients treated with alteplase thrombolysis for acute myocardial infarction. DESIGN: Double blind randomised trial. TREATMENT REGIMENS: Alteplase 100 mg (not weight adjusted) plus aspirin (250 mg intravenously followed by 75-125 mg on alternate days) plus heparin (5000 units intravenously followed by 1000 units hourly without dose adjustment) was compared with alteplase plus aspirin plus placebo for heparin. SETTING: 19 cardiac centres in six European countries. SUBJECTS: 652 patients aged 21-70 years with clinical and electrocardiographic features of infarcting myocardium in whom thrombolytic therapy could be started within six hours of the onset of major symptoms. MAIN OUTCOME MEASURE: Angiographic coronary patency 48-120 hours after randomisation. RESULTS: Coronary patency (TIMI grades 2 or 3) was 83.4% in the heparin group and 74.7% in the group given placebo for heparin. The relative risk of an occluded vessel in the heparin treated group was 0.66 (95% confidence interval 0.47 to 0.93). Mortality was the same in both groups. There were non-significant trends towards a smaller enzymatic infarct size and a higher incidence of bleeding complications in the group treated with heparin. CONCLUSIONS: Concomitant intravenous heparin improves coronary patency in patients with alteplase. Whether this can be translated into improved clinical benefit needs to be to be tested in a larger trial.

Adult↗

PubMed1992

Clinical risk assessment after first myocardial infarction--is additional noninvasive testing necessary?

In order to assess whether the outcome of MI can be predicted by clinical data alone or whether and how much noninvasive testing is necessary to predict cardiac events or death, 361 patients were prospectively evaluated and followed for up to five years. A recursive partitioning analysis indicated that high-risk patients can be identified clinically after MI with a high degree of accuracy; to separate low-risk patients who need no further investigation or therapy, however, one additional noninvasive test is necessary which allows quantification of myocardial damage as well as exercise-induced ischemia. Additional tests added little to this risk prediction, indicating that multiple noninvasive testing should not be performed.

Adult↗

PubMed1991

[Are ECG criteria for indications for thrombolysis in acute myocardial infarct defined too narrowly?].

BACKGROUND: Despite the advantages of fibrinolytic therapy in acute myocardial infarction only about 20% of these patients receive this therapy. We studied patients excluded from fibrinolysis to identify subgroups with high mortality, which could derive benefit from more liberal interpretation of the indications for fibrinolytic therapy. METHODS: Retrospective chart review to identify patients with acute myocardial infarction in our coronary care unit 7/88-7/89. All patients received a questionnaire one year after this myocardial infarction. Patients not answering the questionnaire were contacted by phone or the information was sought from their physician. Indications for thrombolysis (with streptokinase or rTPA) were ST elevations of greater than or equal to 2 mm in greater than 2 adjacent leads and the absence of contraindications. RESULTS: In 231/242 (95%) of the identified patients a complete follow-up was obtained, 32% were age greater than 70 years, 30% were admitted greater than 6 h after the beginning of the symptoms, 64% did not fulfil the ECG criteria for thrombolysis, 21% (49/231) received thrombolytic therapy. The mortality after one year was 20.3% in patients not treated with thrombolysis and 8.2% in patients with thrombolysis (difference 12.1%, 95% confidence interval 2.9-21.3%, p = 0.048). Patients with preceding old infarctions (n = 58) fulfilled the ECG criteria for thrombolysis in a significantly smaller proportion (21% vs 41%, p = 0.004). Of all patients 12% were excluded from thrombolytic therapy due to a negative initial ECG and yet developed a Q ware infarction. The one year mortality of patients not given thrombolysis and with a Q wave infarction was 24% (22/93, p = 0.02 as compared to patients with thrombolysis), in patients with non Q wave infarction it was 13% (11/82, p = 0.41) and in patients with ambiguous ECG it was 57% (4/7, p = 0.006). The mortality in patients with a preceding infarction was 31% and significantly higher than in patients with a first infarction (16%, p = 0.049) and in patients receiving thrombolysis (8.2%, p = 0.005). CONCLUSIONS: By excluding patients with acute myocardial infarction from thrombolytic therapy a group with high first year mortality is selected. Most patients are excluded because of an initial ECG not showing enough ischemia to fulfil the criteria for thrombolytic therapy. A prospective study of thrombolytic therapy using less rigid ECG criteria in the subgroups with the highest mortality (patients with preceding myocardial infarction or ambiguous ECG) seems necessary.

Acute Disease↗

PubMed1991

Long-term treatment of ventricular tachycardia with amiodarone in presence of severe left ventricular dysfunction.

A group of 34 consecutive patients with coronary artery disease (n = 29) or dilated cardiomyopathy (n = 5) (3 women, 31 men, age 38-80 yr) who had severely impaired left ventricular function (left ventricular ejection fraction less than or equal to 40%) and high-grade ventricular ectopic activity (sustained or nonsustained ventricular tachycardia or ventricular fibrillation) were treated with amiodarone (mean dose: 206 mg/d) and followed for 1-117 (mean: 49) months. In the total group, there were seven sudden deaths, five deaths due to pump failure, one non-cardiac death, and two successful heart transplantations during follow-up. Thus the annual cardiac mortality in these carefully selected and followed patients was 8, 6%, the annual cardiac event rate was 10, 1%. The cumulative cardiac survival-rate was 62% after 5 years and 41% after 10 years. In five patients, treatment was interrupted after 10 to 43 months, three of the patients were alive at follow-up and two suffered cardiac death, resulting in an annual cardiac death rate of 12% in this subgroup of treatment. Based on the results of this retrospective analysis we conclude that in patients with low left ventricular ejection fraction and nonsustained or sustained ventricular tachycardia treated with low dose amiodarone, mortality was unexpectedly low. Thus, it may be the antiarrhythmic treatment to be considered in patients with ventricular tachycardia and severe left ventricular dysfunction.

Adult↗

PubMed1991

Coronary vasodilatation and improved myocardial lactate metabolism after angiotensin converting enzyme inhibition with cilazapril in patients with congestive heart failure.

The effects of angiotensin converting enzyme inhibition on systemic and coronary hemodynamics and on myocardial lactate metabolism were investigated before and 2 and 6 hours after cilazapril at rest and during supine submaximal exercise in 10 patients with New York Heart Association class II or III chronic congestive heart failure. Angiotensin converting enzyme inhibition, indicated by a significant increase in plasma renin activity, resulted in significant reductions in blood pressure and systemic vascular resistance. Myocardial oxygen demand decreased (resting double product 10.9 +/- 3.7 vs 12.2 +/- 3.8 mm Hg beats/min 10(-3); p less than 0.05), but coronary sinus blood flow remained unchanged and calculated coronary resistance decreased (0.45 vs 0.5 units, rest 6 hours; p less than 0.05) suggesting coronary vasodilatation. Changes in coronary vascular resistance were directly related to changes in systemic vascular resistance (r = 0.75, p less than 0.5). Myocardial lactate extraction increased at rest (47 +/- 60 vs 134 +/- 132 mumol/min; p less than 0.5) and during exercise (27 +/- 54 vs 491 +/- 317 mumol/min; p less than 0.05) both in patients with coronary artery disease (n = 5) and idiopathic dilated cardiomyopathy (n = 5). Resting lactate production was converted to lactate extraction in two patients with coronary artery disease. Neither plasma catecholamine nor atrial natriuretic peptide concentrations changed significantly. The results suggest coronary vasodilation and improved aerobic myocardial metabolism by angiotensin converting enzyme inhibition in patients with congestive heart failure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1991

Assessment of the extent of jeopardized myocardium during acute coronary artery occlusion followed by reperfusion in man using technetium-99m isonitrile imaging.

We tested the feasibility of technetium-99m methoxyisobutyl isonitrile (Tc-MIBI) imaging for delineating jeopardized myocardium during acute coronary occlusion and reperfusion in man. This new perfusion agent was injected in 25 patients during elective percutaneous transluminal coronary angioplasty (PTCA) of a single-vessel left anterior descending (LAD) coronary artery stenosis. Distinct perfusion defects were present on "occlusion" images but not on "open vessel" images obtained 20 to 24 hours later in 21 patients (84%). The extent and severity of perfusion defects were significantly smaller in patients with distal versus proximal LAD occlusions (3.4 +/- 1.2 versus 5.2 +/- 1.5 segments; p less than 0.001). The only factor that was significantly related to the presence or absence of such "ischemic" perfusion defects was the absence or presence of visible collateral vessels to the LAD (p less than 0.03). The site of occlusion, presence of wall motion abnormalities, or occlusion time did not influence the results significantly. Thus the myocardial area at risk could be visualized and quantitated by Tc-MIBI imaging even after occlusion times as short as 15 seconds, but functioning collateral vessels are capable of protecting jeopardized myocardium in this setting.

Adult↗

PubMed1991

Prolonged myocardial stunning after thrombolysis: can left ventricular function be assessed definitely at hospital discharge?

To assess whether myocardial dysfunction after acute reperfusion ('stunning') may show delayed recovery, 33 patients of the European Cooperative Study (rtPA vs placebo) had radionuclide angiocardiography on day 9 and after 3-6 months. Sixteen patients (13 inferior, three anterior infarcts) had a normal left ventricular ejection fraction (LVEF) which remained unchanged (55.4 vs 53.9%). In contrast, LVEF of 17 patients (10 inferior, seven anterior infarcts) with depressed values on day 9 improved during follow-up from 38.8 to 45.2% (P less than 0.01). Improvement was only observed in patients with early reperfusion defined a priori as peak creatine kinase value less than or equal to 15 h of pain onset (from 40.9 to 49.3%; P less than 0.05) in contrast to patients without reperfusion (from 34.0 to 35.2%; ns). Accordingly, LVEF increased in patients with open infarct-related arteries at hospital discharge (n = 8; P = 0.053) but not with persistent occlusion (n = 7; P = 0.11). Thus, a depressed LVEF observed 9 days after reperfusion may show delayed recovery due to prolonged stunning. Therefore, after thrombolysis, left ventricular function may not be evaluated definitively at hospital discharge; results of such studies should be interpreted with caution.

Adult↗