Moderate patient-prosthesis mismatch after valve replacement for severe aortic stenosis has no impact on short-term and long-term mortality.

BACKGROUND: The importance of moderate patient-prosthesis mismatch (PPM) for the prognosis of patients who undergo aortic valve replacement is unclear. METHODS: The presence of PPM was assessed in 361 consecutive patients undergoing valve replacement for isolated severe aortic stenosis and related to perioperative and postoperative mortality. Indexed effective orifice areas (EOAi) were estimated for each type and size of prosthesis. RESULTS: Using the previously proposed cut-off of EOAi

Afterload reduction in severe aortic regurgitation.

This study was designed to assess the effects of afterload reduction in asymptomatic patients with severe aortic regurgitation (AR) and maintained LV function by cine-MRI. We studied 13 patients at baseline and after 0.2 mg/kg Hydralazine (I.V.). Patients were stratified according to the volumetric LV response to acute afterload reduction: Group I comprised patients with improved LV response; Group II comprised patients with unchanged or deteriorated LV response. Baseline LV function and severity of AR were not significantly different between groups. However, regurgitant fraction decreased (50 +/- 12 vs. 36 +/- 9%; P < 0.03) and cardiac output increased (4.9 +/- 1.4 vs. 7.1 +/- 1.6l/minute; P < 0,001) in Group I and remained unchanged in Group II (54 +/- 10 vs. 55 +/- 10%, P = n.s. and 5.5 +/- 1.4 vs. 6.6 +/- 0.9l/minute; P = n.s.) during maximal vasodilation. Beat-to-beat analysis revealed a decrease of left ventricular endsystolic volume index in group I (48 +/- 13 vs. 37 +/- 9 ml/beat; P < 0.05) and no change in group II (61 +/- 20 vs. 62 +/- 20 ml/beat; P = n.s.). In the natural history of chronic AR, the absence of improved LV performance during acute vasodilation using beat-to-beat analysis by MRI may identify patients with more advanced cardiac adaptation to chronic volume overload.

Assessment of myocardial viability by dobutamine echocardiography, positron emission tomography and thallium-201 SPECT: correlation with histopathology in explanted hearts.

OBJECTIVES: We examined the relationship among viability assessment by dobutamine echocardiography (DE), positron emission tomography (PET) and thallium-201 single-photon emission computed tomography (TI-SPECT) to the degree of fibrosis. BACKGROUND: DE, PET and TI-SPECT have been shown to be sensitive in identifying viability of asynergic myocardium. However, PET and TI-SPECT indicated viability in a significant percentage of segments without dobutamine response or functional improvement after revascularization. METHODS: Twelve patients with coronary artery disease and severely reduced left ventricular function (EF 14.5+/-5.2%) were studied with DE prior to cardiac transplantation: 5 had additional PET and 7 had TI-SPECT studies. Results of the three techniques were compared to histologic findings of the explanted hearts. RESULTS: Segments with >75% viable myocytes by histology were determined to be viable in 78%, 89% and 87% by DE, PET and TI-SPECT; those with 50-75% viable myocytes in 71%, 50% and 87%, respectively. Segments with 25-50% viable myocytes showed response to dobutamine in only 15%, but were viable in 60% by PET and 82% by TI-SPECT. Segments with <25% viable myocytes responded to dobutamine in 19%; however, PET and TI-SPECT demonstrated viability in 33% and 38%, respectively. Discrepant segments without dobutamine response but viability by PET and SPECT had significantly more viable myocytes by pathology than did those classified in agreement to be nonviable but had significantly less viable myocytes than those classified in agreement to be viable (p < .001). CONCLUSIONS: These findings suggest that contractile reserve as evidenced by a positive dobutamine response requires at least 50% viable myocytes in a given segment whereas scintigraphic methods also identify segments with less viable myocytes. Thus, the methods may provide complementary information: Nuclear techniques appear to be highly sensitive for the detection of myocardial viability, and negative tests make it highly unlikely that a significant number of viable myocytes are present in a given segment. Conversely, dobutamine echo may be particularly useful for predicting recovery of systolic function after revascularization.

Relation of hemodynamic variables to augmentation of left anterior descending coronary flow by intraaortic balloon pulsation in coronary artery disease.

Recent studies suggest prophylactic intraaortic balloon-pulsation (IABP) in patients undergoing coronary reperfusion therapy. However, variable effects of IABP on coronary blood flow are reported. It is suggested that augmentation of coronary flow is more effective in patients with a compromised hemodynamic status, which might have potential relevance in selecting IABP treatment in patients undergoing reperfusion therapy.

Significance of morphological abnormalities detected by MRI in patients undergoing successful ablation of right ventricular outflow tract tachycardia.

BACKGROUND: MRI can demonstrate subtle morphological changes of the right ventricle in patients with idiopathic right ventricular outflow tract tachycardia (RVOT). The present study examines the incidence and significance of right ventricular (RV) abnormalities detected by MRI with respect to the site of successful radiofrequency catheter ablation of the clinical tachycardia. METHODS AND RESULTS: The study population comprised 20 patients (mean age, 40+/-12 years) undergoing elimination of recurrent RVOT by radiofrequency catheter ablation. MRI studies were performed before ablation to assess RV volumes and function, as well as structural abnormalities of the RV myocardium. Ten healthy age- and sex-matched subjects served as control subjects. The successful ablation sites, as documented by radiographs of the catheter position, were compared with MRI findings. Patients with RVOT showed no difference in respect to RV volumes and ejection fractions compared with control subjects. Whereas RV abnormalities were limited to prominent fatty deposits of the right atrioventricular groove extending into the inlet portion of the RV wall in 2 of 10 control subjects, MRI studies demonstrated morphological changes of the RV free wall in 13 (65%) of 20 patients with RVOT, including presence of fatty tissue (n=5), wall thinning (n=9), and dyskinetic wall segments (n=4). Eight of these patients had additional fat deposits, thinning, or a saccular aneurysm in the RV outflow tract, corresponding with the ablation site in 6 patients. CONCLUSIONS: In RVOT, structural abnormalities of the right ventricle can be detected in a substantial number of patients despite normal RV volumes and global function. MRI abnormalities within the RV outflow tract are significantly associated with the origin of tachycardia.

Systemic endothelial dysfunction is related to the extent and severity of coronary artery disease.

Flow-mediated vasodilation (FMD) of systemic arteries, a non-invasive parameter of endothelial function, is correlated with cardiovascular risk factors. The relationship between FMD and morphologically and clinically evident coronary artery disease has not been described. This study was performed to test the hypothesis that an impairment of FMD in the brachial artery is related to the presence and/or extent and severity of coronary artery disease (CAD). We examined 74 patients with angina pectoris and 14 control subjects (age 17 36 years). Angiography revealed coronary artery disease (> or = 30% diameter stenosis) in 44 patients (CAD, age 32 67 years) and smooth coronary arteries in 30 patients (non-CAD, age 22-73 years). Vasodilation following reactive hyperemia and after sublingual nitroglycerin (NTG) was assessed in the brachial artery using B-mode high resolution ultrasound. CAD patients showed markedly impaired FMD compared to the non-CAD group (5.7 +/- 4.8 versus 12.6 +/- 6.7%, P < 0.0001) and to controls (5.7 +/- 4.8 versus 15.7 +/- 3.9%, P < 0.00001). NTG induced similar degrees of vasodilation in the CAD and non-CAD groups but less vasodilation in the CAD patients compared to controls (12.2 +/- 6.3 versus 20.4 +/- 6.9%, P < 0.01). On univariate analysis, impaired FMD in CAD patients and non-CAD patients was related to the extent of coronary disease (1-, 2- or 3-vessel disease; r = -0.67, P < 0.0001), to the maximum percent diameter stenosis in one of the major coronary vessels (r = -0.52, P < 0.0001), brachial artery diameter (r = -0.46, P < 0.0001) and plasma cholesterol level (r = -0.34, P < 0.001). On multiple stepwise regression analysis the extent of coronary disease (r = -0.51, P < 0.0001) and the baseline brachial artery diameter (r = -0.37, P < 0.0001) were independently associated with FMD in CAD and non-CAD patients. The present findings suggest that the impairment of FMD in the brachial artery, a marker of systemic endothelial function, is closely related to the angiographic extent of CAD.

Functional characterization of cytokine autoantibodies in chronic renal failure patients.

We have recently reported on an increase of IL-1 alpha and IL-6 autoantibodies in patients maintained on chronic hemodialysis treatment. The aim of the present study was to evaluate functional properties of these autoantibodies. Serum samples of more then 500 chronic renal failure patients with and without replacement therapy were screened for the presence of IL-1 alpha and IL-6 autoantibodies by second antibody precipitation. The neutralizing capacity of IL-1 alpha autoantibody serum was studied by immunofluorescence flow cytometry analysis of IL-1 alpha induced expression of E-selectin (ELAM-1, CD62e) on HUVEC (human umbilical vein endothelial cells). Results of these inhibition studies were confirmed with IgG preparations from antibody positive sera, purified by affinity chromatography. Functional studies on IL-6-dependent B9 cell proliferation were performed with IL-6 autoantibody positive sera, and quantitated with the colorimetric MTT assay. IL-1 alpha induced expression of E-selectin on HUVEC (considered 100% positive cells) was inhibited by each IL-1 alpha autoantibody positive serum sample (N = 13; anti-IL-1 alpha activity: 7.62 to 57.52% binding). Inhibition of E-selectin expression by IL-1 alpha autoantibodies ranged from 0.11 to 80.22% positive cells (0.15 to 92.31% mean fluorescence intensity). A strong correlation of E-selectin expression with IL-1 alpha autoantibody concentration was observed (P < 0.005). Furthermore, IgG eluates from autoantibody positive patients inhibited E-selectin expression to 41.0 +/- 23.1% positive cells if compared with 83.7 +/- 5.7% positive cells of the IgG depleted serum samples.(ABSTRACT TRUNCATED AT 250 WORDS)