Echocardiographic evaluation of prosthetic heart valves.

The specific flow pattern and imaging features of prosthetic heart valves poses major challenges for the Doppler echocardiographic assessment of prosthetic valve structure and function. A comprehensive approach that integrates several semi-quantitative and quantitative parameters obtained from multiple views is key to appropriately detect and quantitate prosthetic valve dysfunction and complications. In patients with prosthetic valves, and particularly in those with mitral prostheses, transesophageal echocardiography is often required to confirm and/or complement information obtained by transthoracic echocardiography. Three-dimensional echocardiography may provide incremental information for the identification of the underlying etiology of prosthetic valve stenosis or regurgitation. Transcatheter aortic valve implantation has rapidly expanded in the past 10 years and paravalvular regurgitation is frequent following this procedure. Given that paravalvular regurgitant jets are often multiple, irregular, and eccentric, the grading of this type of regurgitation is particularly challenging and requires an integrative multiwindow, multiplane, multiparametric approach.

Determinants of aortic bioprosthetic valve calcification assessed by multidetector CT.

BACKGROUND: Cusp calcification is the main mechanism leading to bioprosthetic heart valve (BPV) failure. Recent studies suggest that BPV calcification is an active rather than passive process probably modulated by several mechanisms including lipid-mediated inflammation and dysfunctional phosphocalcic metabolism. OBJECTIVE: To identify the clinical and metabolic determinants of BPV calcification assessed by multidetector CT (MDCT). METHODS AND RESULTS: Presence of BPV calcification was assessed by MDCT in 194 patients who had undergone aortic valve replacement. A calcification score was individually calculated and expressed in mm(3). Patients also underwent a clinical evaluation, a Doppler echocardiographic exam, and a plasma lipid and phosphocalcic profile. 46 patients (24%) had BPV calcification (cusp calcification score >0 mm(3)). After adjustment for age, gender, and time interval since BPV implantation, increased calcium-phosphorus product (OR 1.11, 95% CI 1.01 to 1.23 per 1 unit; p=0.02) and the presence of prosthesis-patient mismatch (OR 3.67, 95% CI 1.25 to 10.6; p=0.01) were the strongest independent factors associated with BPV calcification. Calcium supplement intake, age and female gender were independently associated with increased calcium-phosphorus product. CONCLUSIONS: This study suggests that higher calcium-phosphorus product and prosthesis-patient mismatch promote BPV calcification. Furthermore, this study reports that calcium supplements, which are extensively prescribed in elderly patients, are independently associated with higher calcium-phosphorus product.

Two-dimensional strain for the assessment of left ventricular function in low flow-low gradient aortic stenosis, relationship to hemodynamics, and outcome: a substudy of the multicenter TOPAS study.

BACKGROUND: Decision making in patients with low flow-low gradient aortic stenosis mainly depends on the actual stenosis severity and left ventricular function, which is of prognostic importance. We used 2-dimensional strain parameters measured by speckle tracking at rest and during dobutamine stress echocardiography to document the extent of myocardial impairment, its relationship with hemodynamic variables, and its prognostic value. METHODS AND RESULTS: In 47 patients with low flow-low gradient aortic stenosis, global peak systolic longitudinal strain (PLS) and peak systolic longitudinal strain rate (PLSR) were analyzed. PLS and PLSR at rest and peak stress were -7.56±2.34% and -7.41±2.89% (P=NS) and -0.38±0.12 s(-1) and -0.53±0.18 s(-1) (P<0.001), respectively. PLS and PLSR inversely correlated with left ventricular ejection fraction at rest (rs=-0.52; P<0.0001 and -0.38; P=0.008) and peak stress (rs=-0.39; P=0.007 and -0.45; P=0.002). The overall 2-year survival rate was 60%. Univariate predictors of survival were peak stress left ventricular ejection fraction (P=0.0026), peak stress PLS (P=0.0002), peak stress PLSR (P<0.0001), and N-terminal pro-B-type natriuretic peptide (P<0.0001). Three hierarchically nested multivariable Cox regression models were constructed-model 1: The Society of Thoracic Surgeons score as an indicator of clinical risk (area under the receiver operating characteristic=0.59); model 2: model 1+N-terminal pro-B-type natriuretic peptide and peak stress left ventricular ejection fraction (area under the receiver operating characteristic=0.83; incremental P<0.0001); model 3: model 2+peak stress PLSR (area under the receiver operating characteristic=0.89; incremental P=0.035). CONCLUSIONS: In patients with low flow-low gradient aortic stenosis, 2-dimensional strain parameters are strong predictors of outcome. Peak stress PLSR may add incremental prognostic value beyond what is obtained from N-terminal pro-B-type natriuretic peptide and peak stress left ventricular ejection fraction. A larger study is needed to confirm these findings.

Impact of orlistat-induced weight loss on diastolic function and heart rate variability in severely obese subjects with diabetes.

Objective. Determine the impact of Orlistat-induced weight loss on metabolic profile and cardiovascular function in severely obese patients with type 2 diabetes. Methods. Twenty-nine patients were randomized either to a nonplacebo control group or to a treatment group with Orlistat thrice a day. Metabolic profile, anthropometric parameters, heart rate variability indices, and echocardiographic variables were measured before and after a 12-week treatment period. Results. Treatment with Orlistat induced a modest but significant weight loss compared to controls (3.7 ± 3.0 versus 0.5 ± 2.2 kg, resp.; P = .003). There was significant decrease in fasting glycemia (7.9 ± 3.0 versus 6.7 ± 2.2 mmol/L; P = .03) and significant improvements in left ventricular diastolic function (P = .03) and in the sympathovagal balance (LF/HF ratio) (P = .04) in the Orlistat group. Conclusion. These results suggest that a modest weight loss improves fasting glycemia, left ventricular diastolic function, and sympathovagal balance in severely obese patients with type 2 diabetes.

A simple Doppler echocardiography method to evaluate pulmonary capillary wedge pressure in patients with atrial fibrillation.

OBJECTIVE: The accuracy of E/E' ratio has not been validated in atrial fibrillation (AF). The objective of this study is to compare the accuracy of the E/E' ratio averaged over a sample of 10 cardiac cycles and E/E' ratio obtained in the cycle with the longest RR interval for the estimation of wedge pressure in patients with AF using a simultaneous pulmonary artery occlusive pressure measured with a Swan-Ganz catheter. DESIGN: Twenty-four consecutive patients with AF with a Swan-Ganz catheter were recruited in this study. The majority of patients (92%) were in the early postoperative phase of cardiac surgery. RESULTS: The best sensitivity and specificity was reached with E/E' ratio in the medial position using the one-beat method; E/E' ratio > or = 16 with one beat predicts a wedge pressure >15 mmHg with a sensitivity and specificity of 91% and 85%, respectively. CONCLUSIONS: Measuring E/E' ratio using the one-beat method is a simple and clinically accurate way to estimate wedge pressure in patients with AF.

Normalization of diastolic dysfunction in type 2 diabetics after exercise training.

PURPOSE: The purpose of this study was to evaluate the impact of aerobic exercise training on left ventricular diastolic dysfunction (LVDD) and exercise capacity in subjects with type 2 diabetes. METHODS: Twenty-three sedentary subjects with well-controlled type 2 diabetes, free of coronary disease and having different degrees of LVDD, participated in the study. Subjects were treated with oral hypoglycemic agents and/or diet. Eleven subjects (EX) (age: 58 +/- 5 yr; mean +/- SD) underwent a 3-month aerobic exercise training program using a cycle ergometer, whereas a control group (CONT) of 12 subjects (57 +/- 6 yr) maintained their activities of daily living. Exercise capacity and LVDD, using echocardiography, were evaluated before and after the 3-month exercise program. RESULTS: At baseline, anthropometric data were similar between the groups, except for body mass index (BMI), which was higher in CONT (31 +/- 3 vs 28+/- 3 kg x m(-2); P < 0.05). There were no significant differences in glycemic control (HbA1c: 6.4 +/- 1.2 vs 5.8 +/- 1.3%; P = 0.2) or maximal oxygen uptake (26.7 +/- 5.9 vs 28.6 +/- 3.9 mL x kg(-1) x min(-1); P = 0.4) between groups. Normalization of LVDD was observed in 5 of 11 EX subjects, (P < 0.0001) of whom four had grade 1 LVDD before exercise training. No change in diastolic function was observed in the CONT group. After exercise training, maximal oxygen uptake increased in the EX group (28.6 +/- 3.9 vs 32.7 +/- 5.7 mL x kg(-1) x min(-1); P < 0.05), whereas there was no change in the CONT group (26.7 +/- 5.9 vs 27.3 +/- 6.2 mL x kg(-1) x min(-1); P = 0.58). In both groups, there was no significant change in BMI. CONCLUSIONS: Along with an improvement in exercise capacity, aerobic exercise training has the potential to reverse LVDD in patients with well-controlled, uncomplicated type 2 diabetes.

Value and limitations of peak-to-peak gradient for evaluation of aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: In patients with aortic stenosis (AS), it has been reported that the transvalvular pressure gradients (APs) may be reduced or even abolished in the presence of concomitant arterial hypertension, but the mechanisms underlying this phenomenon remain unclear. The study aim was to: (i) examine the relationship between systemic arterial hemodynamics and the peak-to-peak (deltaP(PtoP)), peak deltaP and mean deltaP; and (ii) propose and validate a new formula for the non-invasive estimation of the deltaP(PtoP) and of the peak left ventricular systolic pressure (LVSP) using Doppler echocardiography. METHODS: Two fixed stenoses (geometric orifice area 1.0 and 1.35 cm2) and one bioprosthesis (effective orifice area (EOA) 1.2 cm2) were tested in a mock flow circulation model. Systemic vascular resistance (R) was increased from 1,500 to 3,300 dyne.s/cm5, and systemic arterial compliance (C) was decreased from 2.9 to 0.9 ml/mmHg, while transvalvular flow was held constant. RESULTS: Neither C nor R had any significant impact on EOA, peak deltaP and mean deltaP. deltaP(PtoP) was decreased markedly, however, when C was reduced (bioprosthesis: -15 mmHg (-69%); orifice 1.35 cm2: -24 mmHg (-30%); cm2: (-13%)). Subsequently, an equation was proposed to predict deltaP(PtoP) from EOA, mean deltaP, and C measured by Doppler echocardiography. LVSP calculated by adding the predicted deltaP(Ptop) to systolic arterial pressure (SAP) was compared with LVSP measured directly in a dataset of 24 pigs with experimentally induced AS. There was a strong agreement between the estimated and measured LVSP (r = 0.97; mean absolute error 5 +/- 5 mmHg). CONCLUSION: deltaP(Ptop) should not be used to evaluate AS severity because, as opposed to peak and mean deltaPs, it is highly influenced by C. The new non-invasive method proposed in this study to estimate the LVSP may be useful for obtaining a more accurate estimate of global LV afterload in patients with AS.

Metabolic and cardiovascular improvements after biliopancreatic diversion in a severely obese patient.

BACKGROUND: Severe obesity is associated with important morbidity and increased mortality. The successes of lifestyle modifications and drug therapy have been partial and mostly unsustained in reducing obesity and its comorbidities. Bariatric surgery, particularly biliopancreatic diversion with duodenal switch reduces efficiently excess body weight and improves metabolic and cardiovascular functions. CASE PRESENTATION: A 56-year-old man with severe clinical obesity underwent a biliopancreatic diversion with a duodenal switch after unsuccessful treatment with weight loss pharmacotherapy. He had diabetes, hypertension and sleep apnea syndrome and was on three medications for hypertension and two hypoglycemic agents in addition to > 200 insulin units daily. Eleven months after the surgery, he had lost 40% of his body weight. The lipid profile showed great improvement and the hypertension and diabetes were more easily controlled with no more insulin needed. The pseudonormalized pattern of left ventricular diastolic function improved and ventricular walls showed decreased thickness. CONCLUSION: Biliopancreatic diversion may bring metabolic and cardiovascular benefits in severely obese patients from a cardiovascular perspective.