Progression from partial to complete papillary muscle rupture in acute myocardial infarction.
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Aged↗
Biomedical subjects
G Maurer
Publications and source records attributed to G Maurer.
Thrombolytic therapy in acute myocardial infarction.
Despite major advances made over the last decade, mortality following acute myocardial infarction (MI) is still high even for patients treated with the "front-loaded" recombinant tissue-type plasminogen activator (rt-PA) regimen: 30-day mortality is 6.3%, and it is associated with fatal cerebral hemorrhage in 1.5%. Further improvement of short- and long-term prognosis can be achieved if infusion of the thrombolytic agent starts early, if reperfusion occurs more rapidly, and if a persistent thrombolysis in myocardial infarction (TIMI) grade 3 flow of the infarct-related artery can be achieved. These prerequisites for optimal preservation of ventricular function and predictors of a favorable outcome. New treatment strategies, e.g., more accelerated dosage regimens of established thrombolytic agents, new combination therapies, and new thrombolytic agents, with or without addition of more specific and more potent new antithrombotic agents, may further improve the efficacy of thrombolysis in acute MI during the late 1990s.
Clinical Trials as Topic↗
Diagnosis and management of prosthetic valve dysfunction.
Immediate and long-term prognosis of patients with prosthetic valves critically depends on prevention, rapid diagnosis, and optimal treatment of complications. This review describes the current practice in management of prosthetic dysfunction and discusses unresolved or controversial issues such as: what is the optimal anticoagulation regimen in both mechanical and bioprosthetic heart valves? Is thrombolysis superior to surgery in thrombotic valve obstruction? Is valve replacement superior to conservative therapy for prosthetic valve endocarditis? In addition, recently obtained data relating to the incidence of early and late mortality, thromboembolism, anticoagulation-related hemorrhage, valve thrombosis, hemolysis, paravalvular leakage, and the necessity and risk of reoperation are presented.
Bioprosthesis↗
Urinary excretion of apo(a) fragments. Role in apo(a) catabolism.
The biosynthesis and assembly of lipoprotein(a) [Lp(a)], a marker for atherosclerotic disease, appears to be well understood. However, information is lacking concerning the mode and site of Lp(a) catabolism. Apo(a) is reported to be excreted into the urine. To study the effect of this pathway on the overall catabolism of Lp(a), urinary apo(a) was characterized by immunoblotting. More than 10 distinct apo(a) bands with molecular masses between 30 and 160 kD were observed. Apo(a) fragments were not complexed to apoB. In more than 30 individuals the size of apo(a) bands was comparable irrespective of their apo(a) phenotype, although marked differences in the relative intensities of the bands were observed. Eight batches of 24-hour urine collections collected from one proband at 2-week intervals exhibited a significant correlation between creatinine and apo(a) concentrations as measured by DELFIA (r = .93; P < .01). In 193 healthy volunteers a highly significant correlation was found between urinary apo(a) concentrations normalized to creatinine levels and plasma Lp(a) values (p = 0.659; P < .0001). Of the total plasma apo(a), 0.073%, i.e., 121 micrograms apo(a), was excreted in the form of apo(a) fragments in 24-hour urine samples from 12 healthy volunteers. We conclude that the catabolism of Lp(a) via excretion of apo(a) fragments accounts for < 1% of the daily Lp(a) catabolism.
Adult↗
Revascularization alone or combined with suture annuloplasty for ischemic mitral regurgitation. Evaluation by color Doppler echocardiography.
To determine the effectiveness of revascularization alone or combined with mitral valve repair for ischemic mitral regurgitation, we performed color Doppler echocardiography intraoperatively before and after cardiopulmonary bypass in 49 patients (mean age, 70 +/- 9 years) with concomitant mitral regurgitation and coronary artery disease (triple vessel or left main in 88%; prior infarction in 90%). After revascularization alone (n = 25), the mitral annulus diameter (2.88 +/- 0.44 cm vs 2.88 +/- 0.44 cm), leaflet-to-annulus ratio (1.44 +/- 0.30 vs 1.44 +/- 0.29), and mitral regurgitation grade (1.7 +/- 0.9 vs 1.8 +/- 0.7) remained unchanged (p = NS, postpump vs prepump); mitral regurgitation decreased by 2 grades in only 1 patient (4%). After combined revascularization and mitral valve suture annuloplasty (Kay-Zubiate; n = 24), the annulus diameter decreased (to 2.57 +/- 0.45 cm from 3.11 +/- 0.43 cm), the leaflet-to-annulus ratio increased (to 1.46 +/- 0.25 from 1.20 +/- 0.21), and the mitral regurgitation grade decreased significantly (to 0.9 +/- 0.9 from 2.8 +/- 1.0) (p < 0.01); mitral regurgitation decreased by 2 grades or more (successful repair) in 75%. The origin of the jet correlated with the site of prior infarction (p < 0.05), being inferior in cases of posterior or inferior infarction (67%), and central or broad in cases of combined anterior and inferior infarction (70%). Despite a slightly higher 30-day mortality in the repair group (p = 0.10), there was no significant difference in survival between the 2 surgical groups at 5 years or 8 years. Therefore, in this study of patients with mitral regurgitation and coronary artery disease, reduction in regurgitation grade with revascularization alone was infrequent. Concomitant suture annuloplasty significantly reduced regurgitation by reestablishing a more normal relationship between the leaflet and annulus sizes. The failure rate after suture annuloplasty was 25%; alternative repair techniques such as ring annuloplasty may have a lower failure rate.
Aged↗
Implantable cardioverter-defibrillator dysfunction after coronary artery bypass grafting.
Displacement of an ICD electrode is a possible complication after changes in heart size after CABG and simultaneous implantation of an epicardial lead ICD. To prevent potentially life-threatening ICD dysfunction in patients who are candidates for CABG and ICD implantation, we suggest the use of transvenous ICD systems or a staged procedure (CABG followed by ICD implantation) rather than a simultaneous operation.
Coronary Artery Bypass↗
Estimation of coronary flow reserve by transesophageal coronary sinus Doppler measurements in patients with syndrome X and patients with significant left coronary artery disease.
OBJECTIVES: This study sought to determine the feasibility of coronary sinus flow velocity analysis by transesophageal Doppler echocardiography for estimation of coronary flow reserve in patients with syndrome X and patients with coronary artery disease. BACKGROUND: Coronary flow reserve provides useful information in patients with coronary artery disease and patients with syndrome X. Current methods of measuring coronary flow reserve are invasive or require extensive laboratory equipment, or both. Transesophageal Doppler recordings of coronary sinus flow velocity before and after vasodilator application may allow noninvasive determination of coronary flow reserve. METHODS: We obtained coronary sinus flow velocity recordings before and after dipyridamole administration (0.6 mg/kg body weight per 5 min) in 9 patients with syndrome X, 14 with significant left coronary artery disease and 22 age-matched control patients. We used the formula anterograde minus retrograde flow velocity time integral times heart rate as an index of coronary sinus flow. Coronary flow reserve was calculated by dividing coronary sinus flow variables after dipyridamole administration by the respective baseline values. RESULTS: Technically adequate recordings were obtained in 44 (98%) of 45 patients. Compared with that in the control group (2.78 +/- 0.95 [mean +/- SD]), coronary flow reserve was significantly lower in patients with syndrome X (1.21 +/- 0.23, p < or = 0.001) as well as in those with coronary artery disease (1.47 +/- 0.7, p < or = 0.001). Using a cutoff coronary flow reserve value of 1.8, sensitivity, specificity and overall predictive value of coronary flow reserve determinations were, respectively, 100%, 91% and 94% for syndrome X and 86%, 91% and 89% for coronary artery disease. CONCLUSIONS: Coronary flow reserve calculation by transesophageal coronary sinus flow velocity recordings is feasible in a large proportion of patients and might be useful for the noninvasive evaluation of patients with syndrome X and patients with severe left coronary artery disease.
Blood Flow Velocity↗
Partial papillary muscle rupture complicating acute myocardial infarction. diagnosis by multiplane transoesophageal echocardiography.
Papillary muscle rupture is a rare but generally fatal mechanical complication of acute myocardial infarction. In contrast to complete papillary muscle rupture, echocardiographic recognition of partial papillary muscle rupture has rarely been reported and seems to be more challenging. We describe a patient with partial papillary muscle rupture that could only be diagnosed by multiplane transoesophageal echocardiography, whereas transthoracic echocardiography and single plane transesophageal echocardiography showed only posterior mitral leaflet prolapse.
Echocardiography, Transesophageal↗
Human liver cytochrome P4503A biotransformation of the cyclosporin derivative SDZ IMM 125.
In humans, cytochrome P4503A (CYP3A) is the major cytochrome P450 gene family that metabolizes SDZ IMM 125 (IMM) to its primary metabolites. Human liver microsomes could be used for this study, because the metabolite profile matched that found in human blood. The apparent affinity (KM) of IMM for the cytochrome P450 proteins (5.1 +/- 1.8 microM) is similar to that of cyclosporin A (CSA). CSA competitively inhibited the metabolism of IMM, increasing the KM 2- and 4.6-fold in the presence of 4 and 10 microM CSA, respectively (Ki 3.8 +/- 1.1 microM). Ketoconazole exhibited competitive inhibition kinetics toward IMM biotransformation, increasing the KM of IMM 1.8-fold at 0.5 microM ketoconazole and 3.5-fold at 1 microM ketoconazole, with no effect on Vmax (Ki of 0.5 +/- 0.4 microM). These results indicate that both CSA and ketoconazole would cause drug interactions, interfering with the biotransformation of IMM. The metabolism of IMM was also greatly inhibited (approximately 80%) by the CYP3A suicide substrate triacetyloleandomycin and a CYP3A inhibitory antibody, indicating the involvement of CYP3A proteins in the biotransformation of IMM. Confirmation of CYP3A4 involvement in the formation of the three primary IMM metabolites was demonstrated with recombinant cells expressing human CYP3A4. Therefore, compounds interacting with CYP3A proteins are expected to cause drug-drug interactions (i.e. the antimycotics ketoconazole and clotrimazole, the steroids ethinylestradiol and testosterone, the ergots, the calcium channel blocker nifedipine, and the immunosuppressants FK-506 and rapamycin).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
High intensity, low frequency catheter-delivered ultrasound dissolution of occlusive coronary artery thrombi: an in vitro and in vivo study.
OBJECTIVES: This study assessed the efficacy of a new high intensity, low frequency therapeutic coronary ultrasound catheter for thrombus dissolution in vitro and in vivo in canine coronary arteries. BACKGROUND: Therapeutic ultrasound has been shown to dissolve thrombi in vitro and in peripheral arteries in vivo. There have been no previous studies on in vivo coronary thrombus dissolution by ultrasound. METHODS: In vitro, we exposed 1- to 4-h old human blood clots for 3 min to pulsed-wave ultrasound. Clot dissolution under various conditions was evaluated. In vivo occlusive coronary thrombi were induced in 18 dogs. RESULTS: In vitro irrigation alone (10 ml/min of normal saline solution) and ultrasound alone each contributed to a reduction of clot weight by 47.1 +/- 11.4 mg and 84.6 +/- 25.6 mg, respectively, after 3 min (p < 0.001). Ultrasound plus irrigation resulted in a reduction of clot weight by 216.5 +/- 31.5 mg after 3 min (p < 0.001). The magnitude of clot dissolution was considerably amplified when ultrasound energy was combined with irrigation, probably because of cavitational effects. In vivo, in three dogs mechanical passage of the unactivated probe failed to recanalize the artery, and the arteries remained thrombotically occluded. After passage of the activated ultrasound probe, angiography revealed widely patent coronary arteries in 13 of 15 dogs and partial recanalization with filling defects indicative of residual thrombus in 2 of 15 dogs. Three of 15 coronary arteries were histologically free of residual thrombi. Mural thrombi extending to < or = 10% of the vessel circumference were seen in 10 of 15 dogs. Residual thrombi > or = 50% of the vessel circumference were found in two cases. There was no histologic evidence of ultrasound-mediated vessel damage. CONCLUSIONS: Catheter-delivered therapeutic ultrasound effectively dissolves clots in vitro and in canine coronary arteries in vivo. Thus, therapeutic catheter-delivered ultrasound has the potential to serve as an adjunct or alternative treatment for thrombus-mediated coronary ischemic syndromes or myocardial infarction.
Animals↗
Identification of intracoronary thrombus and demonstration of thrombectomy by intravascular ultrasound imaging.
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Coronary Thrombosis↗
Gated technetium-99m sestamibi for simultaneous assessment of stress myocardial perfusion, postexercise regional ventricular function and myocardial viability. Correlation with echocardiography and rest thallium-201 scintigraphy.
OBJECTIVES: This study compares technetium-99m sestamibi (sestamibi) electrocardiographic (ECG) gated single-photon emission computed tomography (gated SPECT) and echocardiography for the evaluation of myocardial function and assesses the feasibility of single-injection, single-acquisition stress perfusion/rest function technetium-99m sestamibi-gated SPECT as an alternative to conventional stress/rest imaging for assessment of myocardial perfusion and viability. BACKGROUND: Simultaneous assessment of stress perfusion and rest function is possible with gated SPECT acquisition of stress-injected technetium-99m sestamibi. METHODS: Rest thallium-201 SPECT followed by stress sestamibi-gated SPECT (acquired 0.5 to 1 h after sestamibi injection) was performed in 58 patients. Echocardiography was performed immediately after or before gated SPECT in 43 of the patients. All studies were analyzed by semiquantitative visual scoring. Sestamibi-gated SPECT studies were read for stress perfusion and rest wall motion and thickening. Reversibility on sestamibi-gated SPECT was defined as the presence of a definite stress defect with normal or mildly impaired wall motion or thickening on gated SPECT: RESULTS: There was high segmental score agreement between gated SPECT and echocardiography for wall motion (91%, kappa = 0.68, p < 0.001) and thickening (90%, kappa = 0.62, p < 0.001). Correlation for global wall motion (r = 0.98, p < 0.001) and thickening (r = 0.96, p < 0.001) scores between the two modalities was excellent. In 32 patients without previous myocardial infarction, there was excellent agreement for reversibility between stress sestamibi-gated SPECT and rest thallium-201/stress sestamibi (98%, kappa = 0.93, p < 0.01). However, in 26 patients with previous infarction, discordance between the two approaches was frequent, with 26% (20 of 78) of nonreversible defects by stress sestamibi-gated SPECT being reversible by rest thallium-201/stress sestamibi and 21% (23 of 112) of reversible defects by stress sestamibi-gated SPECT being nonreversible by rest thallium-201/stress sestamibi. CONCLUSIONS: Gated SPECT of stress-injected sestamibi correlates well with echocardiographic assessment of regional function and thus adds information to perfusion SPECT: In patients without previous myocardial infarction, a single-injection stress perfusion/rest function approach using sestamibi-gated SPECT can substitute for conventional stress/rest myocardial perfusion imaging, adding a rest perfusion study only if there are nonreversible defects or consideration of attenuation artifacts. In patients with previous myocardial infarction, the gated SPECT approach does not replace the need for a rest perfusion study.
Aged↗
Catheter-delivered high intensity, low frequency ultrasound induces vasodilation in vivo.
This study investigated the effect of intravascular high intensity, low frequency catheter-delivered ultrasound on vasomotor behaviour in vivo. Catheter-delivered therapeutic ultrasound induces endothelium-independent vasodilation in vitro. To study this effect in vivo we analysed the angiograms of canine coronaries and human femoropopliteal arteries before and after ultrasound exposure. Vasomotor behaviour was studied using a computer edge detection program. We analysed the angiograms of: (1) eight canine left coronary arteries before and after ultrasound; (2) eight canine left coronaries only subjected to serial angiograms, and three canine left coronary arteries of two dogs after passing the unactivated ultrasound probe down the coronary artery infusing saline at a rate of 10-20 ml.min-1, which served as controls, and (3) eight angiographically normal human arterial sites proximal to occlusions in eight femoropopliteal arteries of patients undergoing ultrasound angioplasty for peripheral vascular disease. Vessel diameter of canine coronaries after ultrasound exposure increased from 2.3 +/- 0.3 mm to 2.8 +/- 0.3 mm (21 +/- 2.3%) (P < 0.01). There was no change in vascular diameter in controls after multiple angiograms (2.4 +/- 0.3 mm vs 2.5 +/- 0.2 mm (4.2 +/- 0.2%) (P = ns). Average vessel diameter after passage of the unactivated probe with saline infusion decreased in the left anterior descending coronary artery from 3.66 mm to 3.13 mm, and in the left circumflex coronary artery from 2.88 mm to 2.62 mm. Vessel diameter in human femoropopliteal arteries increased from 3.2 +/- 0.2 mm to 3.6 +/- 0.5 mm or by 14.3 +/- 2.9% respectively (P < 0.01) after exposure to ultrasound energy.(ABSTRACT TRUNCATED AT 250 WORDS)
Angioplasty↗
Pregnancy following renal transplant.
Pregnant patients who have experienced a renal transplant require specialized obstetric management and nursing interventions. Patient care must be developed in a multidisciplinary approach that addresses the needs of the pregnancy as well as the allograft status. Medications to protect the allograft from rejection present unique concerns in the clinical care management of pregnant women. This article describes the collaborative patient care that brings these areas together and reviews nursing interventions and therapies appropriate for the patient who experiences a pregnancy following renal transplant.
Adult↗
Histopathologic correlation of the three-layered intravascular ultrasound appearance of normal adult human muscular arteries.
The purpose of this study was to correlate intravascular ultrasound images from normal peripheral muscular arteries with the microscopic arterial components by using surgical microdissection techniques. There has been uncertainty about the precise anatomic constituents that are represented by the intravascular ultrasound three-layer image in human peripheral arteries. Forty of 66 grossly normal human femoropopliteal arterial segments obtained at autopsy were found to have a three-layered appearance and were subjected to selective surgical microdissection of intima, media, or adventitia. After microdissection, arteries were imaged with a 30 MHz intravascular ultrasound system; two observers blindly reviewed video tapes to assess for the presence or absence of a one-, two-, or three-layered arterial appearance. Removal of internal elastic lamina and/or intima results in a weak but evident inner ultrasound acoustic interface as a result of the media, which is normally echo-lucent. Removal of the adventitia and/or external elastic lamina results in a weak outer ultrasound acoustic interface. Isolated removal of the media does not alter the three-layered ultrasound image. In normal adult human femoropopliteal arteries the inner bright acoustic reflection (layer) is derived from the interface of blood with the intima and internal elastic lamina and the second bright interface (third layer) is from the external elastic lamina and adventitia. The mid-echo-lucent zone is the result of the media. However, any portion of the arterial wall, including muscular media, can act as an acoustic interface.
Adult↗
Enhancement of thrombolysis by external ultrasound.
The purpose of our study was to assess the efficacy of external ultrasound to enhance in vitro thrombolysis with urokinase or streptokinase. One-hour-, 1-day-, 4-day-, and 6-day-old human blood thrombi (n = 366) were incubated in normal saline solution with three different concentrations of streptokinase (50, 250, and 2000 mu/ml) or urokinase (200, 2000, and 5000 mu/ml). Thrombi were exposed to pulsed ultrasound of 1 MHz at 1.0, 1.5 and 2.2 W/cm2 at different exposure times. The combination of ultrasound (2.2 W/cm2, 30 min) and urokinase or streptokinase enhanced lysis rate by an average of 25% compared with lysis with thrombolytic agents alone (p < 0.05). The enhancement was greater at higher ultrasound power outputs (2.2 W/cm2 > 1.5 W/cm2 > 1.0 W/cm2). At higher-power outputs there was no increase of temperature in the solution containing the thrombus. The extent of lysis was higher with longer ultrasound exposure time and with fresh thrombi. These data suggest that use of external ultrasound has the potential to increase both efficacy and rate of thrombolysis.
Combined Modality Therapy↗
The impact of a 'guided self-help group' on bulimic women: a prospective 15 month study of attenders and non-attenders.
Bulimic women (N = 19) interested in a 'guided self-help group' were assessed by structured interviews and standardized tests. Eleven decided to attend the group, eight did not. Ten attenders (regular attendance of at least 6 months) and five non-attenders were followed for up to 6 months (mail questionnaires) and for 15 months (interviews) respectively. All the attenders and four non-attenders initially fulfilled DSM-III-R criteria for bulimia nervosa. After 15 months five attenders still met these criteria, whereas five improved to the point that they no longer did. Attenders showed significant improvement in specific psychopathology (drive for thinness, bulimia), general psychopathology (depression) and psychosocial adjustment, whereas non-attenders did not. However, three of five non-attenders also improved to a subclinical level, thus reflecting the natural course of the illness. Despite the small sample size our study indicates self-help as a valuable tool in overcoming an eating disorder.
Adult↗
Transesophageal echocardiographic detection of aortic atheromatosis may provide clues to occult renal dysfunction in the elderly.
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Acute Kidney Injury↗