Reversal of severe pulmonary hypertension with beta blockade in a patient with end stage left ventricular failure.
(1/1123)
A 52 year old man with severe chronic left ventricular failure (New York Heart Association class IV) was considered unsuitable for cardiac transplantation because of high and irreversible pulmonary vascular resistance (PVR). In an attempt to produce symptomatic improvement, metoprolol was cautiously introduced, initially at 6.25 mg twice daily. This was slowly increased to 50 mg twice daily over a two month period and continued thereafter. After four months of treatment the patient's symptoms had improved dramatically. His exercise tolerance had increased and diuretic requirements reduced to frusemide 160 mg/day only. Assessment of right heart pressures was repeated and, other than a drop in resting heart rate, there was little change in his pulmonary artery pressure or PVR. His right heart pressures were reassessed showing a pronounced reduction in pulmonary artery pressure and a significant reduction in PVR, which fell further with inhaled oxygen and sublingual nitrates. He was then accepted onto the active waiting list for cardiac transplantation. A possible mechanism of action was investigated by assessing responses to beta agonists during treatment. Not only was there pronounced improvement in PVR but it was also demonstrated that beta receptor subtype cross-regulation may have contributed to the mechanism of benefit. (+info)
Recovery of contractility of viable myocardium during inotropic stimulation is not dependent on an increase of myocardial blood flow in the absence of collateral filling.
(2/1123)
OBJECTIVES: The purpose of this study was to determine whether contractile recovery induced by dobutamine in dysfunctioning viable myocardium supplied by nearly occluded vessels is related to an increase in blood flow in the absence of collaterals. BACKGROUND: Dobutamine is used to improve contractility in ventricular dysfunction during acute myocardial infarction. However, it is unclear whether a significant increase in regional blood flow may be involved in dobutamine effect. METHODS: Twenty patients with 5- to 10-day old anterior infarction and > or =90% left anterior descending coronary artery stenosis underwent 99mTc-Sestamibi tomography (to assess myocardial perfusion) at rest and during low dose (5 to 10 microg/kg/min) dobutamine echocardiography. Rest echocardiography and scintigraphy were repeated >1 month after revascularization. Nine patients had collaterals to the infarcted territory (group A), and 11 did not (group B). RESULTS: Baseline wall motion score was similar in both groups (score 15.9+/-1.3 vs. 17.4+/-2.0, p = NS), whereas significant changes at dobutamine and postrevascularization studies were detected (F[2,30] = 409.79, p < 0.0001). Wall motion score improved significantly (p < 0.001) in group A both at dobutamine (-5.3+/-2.2) and at postrevascularization study (-5.5+/-1.9), as well as in group B (-3.9+/-2.8 and -4.5+/-2.4, respectively). Baseline 99mTc-Sestamibi uptake was similar in both groups (62.9+/-9.7% vs. 60.3+/-10.4%, p = NS), whereas at dobutamine and postrevascularization studies a significant change (F[2,30] = 65.17, p < 0.0001) and interaction between the two groups (F[2,30] = 33.14, p < 0.0001) were present. Tracer uptake increased significantly in group A both at dobutamine (+ 10.9+/-7.9%, p < 0.001) and at postrevascularization study (12.1+/-8.7%, p < 0.001). Conversely, group B patients showed no change in tracer uptake after dobutamine test (-0.4+/-5.8, p = NS), but only after revascularization (+8.8+/-7.2%, p < 0.001). CONCLUSIONS: The increase in contractility induced by low dose dobutamine infusion in dysfunctional viable myocardium supplied by nearly occluded vessels occurs even in the absence of a significant increase in blood flow. (+info)
Prognostic value of dobutamine stress echocardiography in predicting cardiac events in patients with known or suspected coronary artery disease.
(3/1123)
OBJECTIVES: The study sought to determine the utility of dobutamine stress echocardiography (DSE) in predicting cardiac events in the year after testing. BACKGROUND: Increasingly, DSE has been applied to risk stratification of patients. METHODS: Medical records of 1,183 consecutive patients who underwent DSE were reviewed. The cardiac events that occurred during the 12 months after DSE were tabulated: myocardial infarction (MI), cardiac death, percutaneous transluminal coronary angioplasty (PTCA), and coronary artery bypass surgery (CABG). Patient exclusions included organ transplant receipt or evaluation, recent PTCA, noncardiac death, and lack of follow-up. A positive stress echocardiogram (SE) was defined as new or worsened wall-motion abnormalities (WMAs) consistent with ischemia during DSE. Classification and regression tree (CART) analysis identified variables that best predicted future cardiac events. RESULTS: The average age was 68+/-12 years, with 338 women and 220 men. The overall cardiac event rate was 34% if SE was positive, and 10% if it was negative. The event rates for MI and death were 10% and 8%, respectively, if SE was positive, and 3% and 3%, respectively, if SE was negative. If an ischemic electrocardiogram (ECG) and a positive SE were present, the overall event rate was 42%, versus a 7% rate when ECG and SE were negative for ischemia. Rest WMA was the most useful variable in predicting future cardiac events using CART: 25% of patients with and 6% without a rest WMA had an event. Other important variables were a dobutamine EF <52.5%, a positive SE, an ischemic ECG response, history of hypertension and age. CONCLUSIONS: A positive SE provides useful prognostic information that is enhanced by also considering rest-wall motion, stress ECG response, and dobutamine EF. (+info)
Integrated evaluation of relation between coronary lesion features and stress echocardiography results: the importance of coronary lesion morphology.
(4/1123)
OBJECTIVES: The aim of this study was to analyze, in the same group of patients, the relationship between multiple variables of coronary lesion and results of exercise, dobutamine and dipyridamole stress echocardiography tests. BACKGROUND: Integrated evaluation of the relation between stress echocardiography results and angiographic variables should include not only the assessment of stenosis severity but also evaluation of other quantitative and qualitative features of coronary stenosis. METHODS: Study population consisted of 168 (138 male, 30 female, mean age 51+/-9 years) patients, on whom exercise (Bruce treadmill protocol), dobutamine (up to 40 mcg/kg/min) and dipyridamole (0.84 mg/kg over 10 min) stress echocardiography tests were performed. Stress echocardiography test was considered positive for myocardial ischemia when a new wall motion abnormality was observed. One-vessel coronary stenosis ranging from mild stenosis to complete obstruction of the vessel was present in 153 patients, and 15 patients had normal coronary arteries. The observed angiographic variables included particular coronary vessel, stenosis location, the presence of collaterals, plaque morphology according to Ambrose classification, percent diameter stenosis and obstruction diameter as assessed by quantitative coronary arteriography. RESULTS: Covariates significantly associated with the results of physical and pharmacological stress tests included for all three stress modalities presence of collateral circulation, percent diameter stenosis and obstruction diameter, as well as lesion morphology (p < 0.05 for all, except collaterals for dobutamine stress test, p = 0.06). By stepwise multiple logistic regression analysis, the strongest predictor of the outcome of exercise echocardiography test was only percent diameter stenosis (p = 0.0002). However, both dobutamine and particularly dipyridamole stress echocardiography results were associated not only with stenosis severity - percent diameter stenosis (dobutamine, p = 0.04; dipyridamole, p = 0.003) - but also, and even more strongly, with lesion morphology (dobutamine, p = 0.006; dipyridamole, p = 0.0009). As all of stress echocardiography results were significantly associated with percent diameter stenosis, the best angiographic cutoff in relation to the results of stress echocardiography test was: exercise, 54%; dobutamine, 58% and dipyridamole, 60% (p < 0.05 vs. exercise). CONCLUSIONS: Integrated evaluation of angiographic variables have shown that the results of dobutamine and dipyridamole stress echocardiography are not only influenced by stenosis severity but also, and even more importantly, by plaque morphology. The results of exercise stress echocardiography, although separately influenced by plaque morphology, are predominantly influenced by stenosis severity, due to a stronger exercise capacity in provoking myocardial ischemia in milder forms of coronary stenosis. (+info)
Functional status and quality of life in patients with heart failure undergoing coronary bypass surgery after assessment of myocardial viability.
(5/1123)
OBJECTIVES: The aim of this study was to evaluate whether preoperative clinical and test data could be used to predict the effects of myocardial revascularization on functional status and quality of life in patients with heart failure and ischemic LV dysfunction. BACKGROUND: Revascularization of viable myocardial segments has been shown to improve regional and global LV function. The effects of revascularization on exercise capacity and quality of life (QOL) are not well defined. METHODS: Sixty three patients (51 men, age 66+/-9 years) with moderate or worse LV dysfunction (LVEF 0.28+/-0.07) and symptomatic heart failure were studied before and after coronary artery bypass surgery. All patients underwent preoperative positron emission tomography (PET) using FDG and Rb-82 before and after dipyridamole stress; the extent of viable myocardium by PET was defined by the number of segments with metabolism-perfusion mismatch or ischemia. Dobutamine echocardiography (DbE) was performed in 47 patients; viability was defined by augmentation at low dose or the development of new or worsening wall motion abnormalities. Functional class, exercise testing and a QOL score (Nottingham Health Profile) were obtained at baseline and follow-up. RESULTS: Patients had wall motion abnormalities in 83+/-18% of LV segments. A mismatch pattern was identified in 12+/-15% of LV segments, and PET evidence of viability was detected in 30+/-21% of the LV. Viability was reported in 43+/-18% of the LV by DbE. The difference between pre- and postoperative exercise capacity ranged from a reduction of 2.8 to an augmentation of 5.2 METS. The degree of improvement of exercise capacity correlated with the extent of viability by PET (r = 0.54, p = 0.0001) but not the extent of viable myocardium by DbE (r = 0.02, p = 0.92). The area under the ROC curve for PET (0.76) exceeded that for DbE (0.66). In a multiple linear regression, the extent of viability by PET and nitrate use were the only independent predictors of improvement of exercise capacity (model r = 0.63, p = 0.0001). Change in Functional Class correlated weakly with the change in exercise capacity (r = 0.25), extent of viable myocardium by PET (r = 0.23) and extent of viability by DbE (r = 0.31). Four components of the quality of life score (energy, pain, emotion and mobility status) significantly improved over follow-up, but no correlations could be identified between quality of life scores and the results of preoperative testing or changes in exercise capacity. CONCLUSIONS: In patients with LV dysfunction, improvement of exercise capacity correlates with the extent of viable myocardium. Quality of life improves in most patients undergoing revascularization. However, its measurement by this index does not correlate with changes in other parameters nor is it readily predictable. (+info)
Effects of phosphodiesterase inhibitors after coronary artery bypass grafting.
(6/1123)
The aim of this study was to estimate the postoperative effects of phosphodiesterase (PDE) inhibitors (milrinone and olprinone) after coronary artery bypass grafting (CABG). To prevent hypotension caused by the PDE inhibitors, low dose of catecholamines were used concomitantly. A total of 34 elective CABG cases were tested. In 12 cases, 0.25 microg kg(-1) min(-1) of milrinone, 3 microg kg(-1) min(-1) of dobutamine (DOB) and dopamine (DOA) were used concomitantly (Group-M). In another 10 patients, 0.1 microg kg(-1) min(-1) of olprinone and the same doses of the catecholamines were infused (Group-O). As a control, the same doses of DOA and DOB only were administered in 12 patients (Group-C). When the pump flow of the cardiopulmonary bypass (CPB) decreased to half, these drugs were given in all groups. Hemodynamics were recorded before CPB, just after the operation, and 3, 6, 12, 24, 48 and 72 h after the operation. Both milrinone and olprinone increased the cardiac index and decreased systemic vascular resistance to almost the same degree. Olprinone decreased mean aortic and pulmonary artery pressures, and also significantly reduced the preload of both right and left heart compared with milrinone. Significant hypotension was not detected due to the concomitant usage of low-dose catecholamines. This concomitant usage of PDE inhibitors and catecholamines allowed easy weaning from CPB, demonstrating excellent hemodynamics after CABG. Good oxygen demand and supply balance were maintained in peripheral tissue. These results suggest that these new PDE inhibitors may be effective not only for weaning from CPB but also for post-cardiotomy cardiogenic shock. (+info)
The functional significance of chronotropic incompetence during dobutamine stress test.
(7/1123)
OBJECTIVE: To investigate the functional significance of chronotropic incompetence during dobutamine stress echocardiography. PATIENTS AND METHODS: The functional significance of chronotropic incompetence was evaluated during dobutamine stress echocardiography in 512 patients without beta blocker treatment who underwent dobutamine stress echocardiography (up to 40 microg/kg/min) and completed the protocol or reached the target heart rate. Mean (SD) age was 60 (12) years (313 men, 199 women). Chronotropic incompetence was defined as failure to achieve 85% of the maximum exercise heart rate predicted for age and sex (220 - age in men; 200 - age in women) at maximum dobutamine dose. RESULTS: Chronotropic incompetence occurred in 196 patients (38%). Affected patients were significantly younger, more likely to be men (both p << 0.001) and smokers (p < 0.05), had a higher prevalence of previous myocardial infarction (p < 0.005) and resting wall motion abnormalities (p < 0. 05), and had a lower resting heart rate (p << 0.001) and systolic blood pressure (p << 0.001) than patients without chronotropic incompetence, but there was no difference in the overall prevalence of ischaemia and significant coronary artery disease. By multivariate analysis, independent predictors of chronotropic incompetence were a lower resting heart rate (p << 0.001), younger age (p << 0.001), and male sex (p << 0.001). CONCLUSIONS: The relations among sex, age, and chronotropic incompetence show the need to titrate the dobutamine dose using specific data based on age and sex related heart rate responses to dobutamine rather than to an exercise stress test. Obtaining specific heart rate criteria is necessary to determine whether chronotropic incompetence represents a real failure to achieve a normal response or is the result of applying an inappropriate gold standard. (+info)
Functional and molecular biological evidence for a possible beta3-adrenoceptor in the human detrusor muscle.
(8/1123)
The possible existence of a beta3-adrenergic receptor (beta3-AR) in the human detrusor muscle was investigated by in vitro functional studies and analysis of mRNA expression. Isoprenaline, noradrenaline and adrenaline each produced a concentration-dependent relaxation of the human detrusor. The rank order for their relaxing potencies was isoprenaline (pD2 6.37+/-0.07) > or = noradrenaline (pD2 6.07+/-0.12) > or = adrenaline (pD2 5.88< or =0.11). Neither dobutamine (beta1- and beta2-AR agonist) nor procaterol (beta2-AR agonist) produced any significant relaxation at concentrations up to 10(-5) M. BRL37344A, CL316243 and CGP-12177A (beta3-AR agonists), relaxed the preparations significantly at concentrations higher than 10(-6) M. The pD2 values for BRL37344A, CL316243 and CGP-12177A were 6.42+/-0.25, 5.53+/-0.09 and 5.74+/-0.14, respectively. CGP-20712A (10(-7) - 10(-5) M), a beta1-AR antagonist, did not affect the isoprenaline-induced relaxation. On the other hand, ICI-118,551, a beta2-AR antagonist, produced a rightward parallel shift of the concentration-relaxation curve for isoprenaline only at the highest concentration used (10(-5) > M) and its pKB value was 5.71+/-0.19. Moreover, SR58894A (10(-7) - 10(-5) M), a beta3-AR antagonist, caused a rightward shift of the concentration-relaxation curve for isoprenaline in a concentration-dependent manner. The pA2 value and slope obtained from Schild plots were 6.24+/-0.20 and 0.68+/-0.31. The beta1-, beta2- and beta3-AR mRNAs were all positively expressed in detrusor smooth muscle preparations in a reverse transcription polymerase chain reaction assay. In conclusion, the present results provide the first evidence for the existence of the beta3-AR subtype in the human detrusor. They also suggest that the relaxation induced by adrenergic stimulation of the human detrusor is mediated mainly through beta3-AR activation. (+info)