Pulmonary Diastolic Pressure Research Articles

Abstract 15201: Diastolic Pulmonary Gradient and Outcomes in Group 1 Pulmonary Hypertension (Analysis of the NIH Primary Pulmonary Hypertension Registry)

Introduction: The National Institute of Health (NIH) registry for primary pulmonary hypertension (PPH) established prognostic factors for PPH (now WHO group 1 PH). Diastolic pulmonary gradient {(DPG), Pulmonary artery diastolic pressure-mean Pulmonary capillary wedge pressure} ≥ 7 mmHg is associated with pulmonary vascular disease and a poor prognosis in heart failure (HF). The prognostic relevance of DPG in group 1 PH is uncertain. Methods: Using the NIH risk stratification equation for 239 patients in the NIH-PPH registry, the 5-year probability of death was calculated. The NIH model was then compared with DPG using a Cox proportional hazards model. Kaplan-Meier survival curves were determined for two cohorts using the median DPG of 30 mmHg as cutoff, and significance was tested using the logrank test. Results: The median age of patients was 38.1 ± 16.0 years old, 63% were female, and 72% had race reported as “white”. The mean DPG was 31.5 mmHg (± 13.6 mm Hg) and only 17.4% of patients had a DPG < 7 mm Hg. In a Cox proportional hazards model, increasing DPG was significantly associated with 5-year mortality even after adjustment for the NIH risk equation (DPG HR 1.18 per 10 mm Hg increase [95% CI 1.05-1.32]), and the chi square statistic for DPG compared favorably with the NIH risk equation (15.6 versus 26.2). When DPG was dichotomized based on the median value of 30 mm Hg, the hazard ratio for DPG > 30 mm Hg with respect to 5-year mortality was 1.91, 95% CI [1.34-2.75] (Figure). In a separate Cox model adjusted for pulmonary artery systolic pressure (PASP), increasing DPG remained significantly associated with decreased survival over 5 years (HR 1.45 for DPG > 30 mm Hg, 95% CI [1.01, 2.10]). Conclusions: DPG has higher distribution in PH than previously reported in HF studies and is associated with survival in group 1 PH patients even after adjustment for the NIH risk equation or PASP. More studies are needed to evaluate the use of DPG in guiding treatment and prognosis in group 1 PH.

Contractile reserve in systemic sclerosis patients as a major predictor of global cardiac impairment and exercise tolerance.

Several studies have evidenced high prevalence of myocardial systolic and diastolic dysfunction among patients with systemic sclerosis (SSc). Exercise echocardiography has shown a diagnostic and prognostic role in identifying early left ventricular (LV) dysfunction in several myocardial pathological settings. The aim of our study was to evaluate early signs of LV impairment under exercise and their correlation to patient's exercise tolerance. Forty-five patients (age 60.4 ± 10.3 years) with SSc and 20 age and sex comparable controls were enrolled in the study. All patients underwent clinical evaluation, 2D echocardiography associated with Tissue Doppler and speckle tracking to evaluate LV deformation indexes, and an exercise echocardiography to evaluate left ventricle contractile reserve (LVCR) and exercise pulmonary pressures. Finally, a 6-minute walking test (6MWT) to evaluate exercise tolerance was also performed. Compared to controls, SSc patients showed an impaired diastolic function (E/E' 10.9 ± 3.7 vs 8.36 ± 2.01; p < 0.01) associated with larger left atrial dimensions (LAVI 28.4 ± 8.7 vs 19.3 ± 4.6 mL/m(2); p < 0.01). During exercise echocardiography, a reduced global longitudinal strain at peak exercise (S-GLS) was highlighted compared to controls (15.7 ± 3.6 vs 18.2 ± 2.2; p = 0.001). A S-GLS cutoff <18%, identified by ROC analysis, identified SSc patients with a reduced diastolic function, exercise tolerance at the 6MWT and higher pulmonary pressures. Our data show that in SSc patients a reduced LVCR characterizes the patients with a more extensive cardiovascular impairment in terms of LV diastolic function, pulmonary pressures and exercise tolerance. These data underline the importance of exercise echocardiography for the preclinical screening of the LV impairment in this population.

Echocardiographic assessment of the right heart in adults

Abstract The right ventricle plays an important role in the morbidity and mortality of patients presenting with signs and symptoms of cardiopulmonary disease. However, the systematic assessment of right heart function is not uniformly carried out. This is due partly to the enormous attention given to the evaluation of the left heart, a lack of familiarity with ultrasound techniques that can be used in imaging the right heart. Aim The parameters recommended for Assessment of RV systolic function & RV diastolic function by Echocardiography. Methods The study population consisted of 285 patients (age: 25–65 years; 56% male) with different cardiovascular diseases referred for echocardiographic assessment at Diagnostic Ultrasound Centre, Echocardiography lab, Cairo University Hospitals. All patients were examined by Transthoracic Echocardiography. Using the parasternal views, apical views & subcostal views. Detailed examinations of the RA & RV were performed. Measurements were taken for RA Dimensions, RV Dimensions & IVC. RV Systolic Function and RV Diastolic Function were described using different techniques. RV Systolic Function was described globally and regionally according to the Complex Coronary Artery Supply. Pressures were measured: Right ventricular systolic pressure (RVSP), Pulmonary artery systolic & diastolic pressures, pulmonary resistance, RA pressures. Results TAPSE should be used routinely as a simple method of estimating RV function, with a lower reference value for impaired RV systolic function of 16 mm. Two-dimensional Fractional Area Change is one of the recommended methods of quantitatively estimating RV function, with a lower reference value for normal RV systolic function of 35%. Interrogation of S’ by pulsed tissue Doppler: simple and reproducible measure to assess RV function. S′ 10 cm/s should raise the suspicion for abnormal RV function, particularly in a younger adult patients. Offline analysis by color-coded tissue Doppler currently remains a research tool, with less data and wider confidence intervals for normal values. MPI used as an Initial and serial measurements as an estimate of RV function. MPI 0.40 using the pulsed Doppler, 0.55 using the pulsed tissue Doppler. It should not be used as the sole quantitative method for evaluation of RV function and should not be used with irregular heart rates. Recommendations: In studies in patients with conditions affected by RV function, RV IVA may be used, and when used, it should be measured at the lateral tricuspid annulus. RV IVA is not recommended as a screening parameter for RV systolic function in the general echocardiography laboratory population. Because of the broad confidence interval around its lower reference limit, no reference value can be recommended. The estimation of PVR is not for routine use but may be considered in subjects in whom pulmonary systolic pressure may be exaggerated by high stroke volume or misleadingly low (despite increased PVR) by reduced stroke volume. PVR should not a substitute for the invasive evaluation of PVR when this value is important to guide therapy. Measurement of RV diastolic function, Transtricuspid E/A ratio, E/E’ ratio, and RA size have been most validated and are the preferred measures. Conclusions In all studies we should examine the right heart using multiple acoustic windows, and the report should represent an assessment based on qualitative and quantitative parameters. The parameters recommended are: (RV) size, right atrial (RA) size, RV systolic function (at least one of the following: fractional area change [FAC], S′, tricuspid annular plane systolic excursion [TAPSE]; with or without RV index of myocardial performance [RIMP]), and systolic pulmonary artery pressure (SPAP) with estimate of RA pressure on the basis of inferior vena cava (IVC) size and collapse.

Doppler echocardiographic evidence of pulmonary hypertension in dogs: a retrospective clinical investigation

Pulmonary hypertension (PH) decreases resistance to fatigue and life expectancy. The aim of this study was to correlate some indirect Doppler indices of PH with tricuspid and pulmonary regurgitation criteria and to relate PH on different indices with the severity of clinical signs. Furthermore the pathogenetic mechanisms associated to PH development were discussed. Dogs with Doppler echocardiographic evidence of PH diagnosed by assessment of pulmonary and tricuspid regurgitant jet velocity were selected, their clinical records were reviewed and a clinical score was computed. Seventeen cases of PH were identified. The degree of PH was assessed based on systolic or diastolic pulmonary pressure and the indirect Doppler indices (AT/ET and Tei Index) were calculated; data were statistically evaluated. Indirect Doppler indices were calculated also in a control group of seven healthy dogs. The most common clinical signs were coughing, dyspnea and syncope; the most common condition associated to PH development was the left-sided valvular heart disease. A significant positive correlation was found between Tei Index and both the systolic pressure and the severity of PH while no correlations were found between PH on different indices and clinical score and/or severity of clinical signs. Results of this study suggest that Tei-index could be an useful support not only to reveal PH but also to give information on the severity of PH. The clinical picture in dogs with PH is apparently unpredictable and not strictly correlated with the severity of PH.

Physiology of the Pulmonary Circulation and the Right Heart

The pulmonary circulation is a high-flow and low-pressure circuit. The functional state of the pulmonary circulation is defined by pulmonary vascular pressure-flow relationships conforming to distensible vessel models with a correction for hematocrit. The product of pulmonary arterial compliance and resistance is constant, but with a slight decrease as a result of increased pulsatile hydraulic load in the presence of increased venous pressure or proximal pulmonary arterial obstruction. An increase in left atrial pressure is transmitted upstream with a ratio ≥1 for mean pulmonary artery pressure and ≤1 the diastolic pulmonary pressure. Therefore, the diastolic pressure gradient is more appropriate than the transpulmonary pressure gradient to identify pulmonary vascular disease in left heart conditions. Exercise is associated with a decrease in pulmonary vascular resistance and an increase in pulmonary arterial compliance. Right ventricular function is coupled to the pulmonary circulation with an optimal ratio of end-systolic to arterial elastances of 1.5-2.

Noninvasive estimation of pulmonary capillary wedge pressure using speckle tracking echocardiography in patients with preserved or reduced ejection fraction

Purpose: Echocardiographic parameters such as a ratio of early mitral inflow velocity (E) to atrial contraction flow velocity (A) and a ratio of E to mitral annular tissue velocity (e') were proposed to estimate left ventricular (LV) diastolic function and pulmonary capillary wedge pressure (PCWP). However, E/A and E/e' have limitations to use in various conditions. Noninvasive estimation of PCWP has not been elucidated. We have recently developed a novel index to estimate PCWP using left atrial (LA) emptying function (EF) and volume (LAV) assessed by speckle tracking echocardiography (STE) and named it kinetics-tracking (KT) index: log (active LAEF/ minimum LAV index). The estimated PCWP (ePCWP) was determined as 10.7 – 12.4 × KT index. The aim was to examine the usefulness of KT index in patients with preserved or reduced ejection fraction to estimate PCWP measured by cardiac catheterization. Methods: We measured phasic LAV and EF obtained from time-LA volume curves by STE during sinus rhythm in consecutive 128 patients (age 67±12, 80 men, 77 patients with LV ejection faction ≥55%) just before cardiac catheterization. Patients with atrial fibrillation, severe mitral regurgitation and mitral stenosis were excluded. LA volume and EF and E/e' were compared with PCWP measured by cardiac catheterization. Moreover, ePCWP estimated by 4 combinations of LA maximum or minimum volume and LA total or active EF was compared with PCWP by cardiac catheterization. Results: The maximum and minimum LAV index were correlated with PCWP (r=0.71 and r=0.78, respectively, p 15 mmHg were 95 and 88%, respectively (AUC = 0.97) using KT index of 17.8 as an optimal cutoff value. In multivariate regression analysis, only KT index was an independent parameter to estimate PCWP by cardiac catheterization in 128 subjects. Conclusions: For noninvasive estimation of LV diastolic function, the KT index is a novel and more accurate predictor of PCWP than LA function, volume solely or E/e'. KT index have an incremental value in routine clinical practice.

Effects of valve geometry and tissue anisotropy on the radial stretch and coaptation area of tissue-engineered heart valves

Tissue engineering represents a promising technique to overcome the limitations of the current valve replacements, since it allows for creating living autologous heart valves that have the potential to grow and remodel. However, also this approach still faces a number of challenges. One particular problem is regurgitation, caused by cell-mediated tissue retraction or the mismatch in geometrical and material properties between tissue-engineered heart valves (TEHVs) and their native counterparts. The goal of the present study was to assess the influence of valve geometry and tissue anisotropy on the deformation profile and closed configuration of TEHVs. To achieve this aim, a range of finite element models incorporating different valve shapes was developed, and the constitutive behavior of the tissue was modeled using an established computational framework, where the degree of anisotropy was varied between values representative of TEHVs and native valves. The results of this study suggest that valve geometry and tissue anisotropy are both important to maximize the radial strains and thereby the coaptation area. Additionally, the minimum degree of anisotropy that is required to obtain positive radial strains was shown to depend on the valve shape and the pressure to which the valves are exposed. Exposure to pulmonary diastolic pressure only yielded positive radial strains if the anisotropy was comparable to the native situation, whereas considerably less anisotropy was required if the valves were exposed to aortic diastolic pressure.

Abstract 142: Vascular Function in Himalayan Healthy High-Altitude Dwellers

Purpose: Endothelial function and carotid intima-media thickness (IMT), are established markers of vascular aging. Aim of the study was to investigate the presence of early markers of atherosclerosis in rural Sherpa population of Kumbu Valley (Nepal), in comparison with lowlanders Caucasian subjects. Methods: 99 Sherpa subjects, living at 2500-3800 m s.l. (34±12 years, BMI 24±3 kg/mq, mean BP 88±9 mmHg), free of cardiovascular disease and risk factors, were recruited, and compared to 60 Caucasian sea-level healthy volunteers (36±12 years, BMI 23±2 kg/mq, mean BP 86±8 mmHg). Endothelial function in the brachial artery (flow-mediated dilation, FMD, and response to glyceryl trinitrate, GTN), and carotid IMT were measured by automated edge-detection system. Left and right ventricular (LV and RV) systolic and diastolic function and pulmonary systolic pressure (PASP), and pulmonary vascular resistance (PVR) were evaluated by echocardiogram. In 11 subjects with reduced FMD, the protocol was repeated, after 100% O 2 administration for 1 hour, titrated to maintain O 2 saturation around 100%. Results: High-altitude group presented higher heart rate and lower pulse pressure than sea-level group. FMD was also reduced (5.2±3.1 vs 6.8±3.0%, p=0.01), despite similar brachial artery diameter (3.7±0.6 vs 3.6±0.7 mm, p=0.64), and response to GTN (8.3±3.1 vs 7.6±2.2%, p=0.13). Conversely, IMT was lower in high altitude group than in the sea-level group (0.51 vs 0.61 mm, p&lt;0.001). Sherpa people showed normal LV and RV systolic and diastolic function, PASP(28±6 mmHg) and PVR (0.16±0.4). In the overall population FMD (5.2±3.1%) was not correlated to O 2 saturation (r=-0.03, p=0.74) and was similar in people with O 2 saturation &gt;90% and in those &lt;90% (5.3 vs 5.0%, p=0.74). In the subgroup receiving O 2 administration, FMD (from 3.1±2.5 to 3.8±2.6, p=0.46), response to GTN (from 8.9±2.7 to 8.7±1.9%), and echocardiographic parameters remained unchanged. Conclusions: Endothelial function is reduced in healthy Sherpa high-altitude dwellers, in the presence of normal RV and LV function and pulmonary pressures, independently of cardiovascular risk factors and hypoxia. This finding is accompanied with a lower IMT and might represent a physiological adaptation to high altitude.

O-46 Continuous paravertebral block versus intravenous analgesia in minimally invasive cardiac surgery via thoracotomy

Method. All patients affected by chronic heart failure and evaluated for heart transplantation, with elevated PVR 3.0 Wood units, PAPm 25 mmHg or PCWP 15 mmHg, were included. The haemodynamic parameters measured by right heart catheterization were: pulmonary systolic, diastolic and mean pressures (PAPs, PAPd, PAPm), wedge pressure (PCWP), cardiac output (CO) and stroke volume (SV). The following variables were derived: transpulmonary pressure gradient (TPG), pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR). All patients were tested by both iNO 20 ppm and 40 ppm and intravenous NaNTP, with increasing dosage, titrated on systemic pressure. The order of administration of iNO and NaNTP was randomly assigned.

Correlation of a Scintigraphic Pulmonary Perfusion Index With Hemodynamic Parameters in Patients With Pulmonary Arterial Hypertension

To determine whether the perfusion index (PI) can be used as a noninvasive measure to diagnose and predict the severity of disease in patients with pulmonary arterial hypertension (PAH). Twenty-two patients were included in this retrospective investigation: 9 controls and 13 patients with PAH. Controls had no evidence of PAH [mean pulmonary arterial pressure (MPAP) ≤25 mm Hg and pulmonary capillary wedge pressure ≤18 mm Hg]. The study patients had PAH (MPAP ≥25 mm Hg and pulmonary capillary wedge pressure ≤18 mm Hg) and no diagnosis of pulmonary embolism. Due to the retrospective nature of the study, the PI was calculated from the posterior perfusion image of a ventilation perfusion scan. The PI was computed as the sum of differences versus control for the 9 deciles above background. Receiver operating characteristic curve analysis was used to compare PI with other parameters for predicting PAH. Linear correlations of PI were found to be significant with the following parameters: pulmonary vascular resistance (r=0.81, P=0.00009), total pulmonary vascular resistance (MPAP/cardiac output) (r=0.80, P=0.00013), pulmonary artery systolic pressure (r=0.73, P=0.00018), MPAP (r=0.72, P=0.00022), pulmonary diastolic pressure (r=0.53, P=0.01), and right atrial pressure (r=0.50, P=0.03). Using logistic regression, the PI was significant in separating patients with PAH from controls (χ²=5.6, P=0.02). The data suggest that PI can be used for the noninvasive diagnosis and measurement of severity of PAH.

Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is a biomarker of cardiac filling pressures in pre-eclampsia

Objective To evaluate if amino-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels reflect intracardiac filling pressures in pre-eclamptic patients. Study design In a cross-sectional study we investigated 22 untreated critically ill pre-eclamptic women between 22 and 34 weeks gestation. All patients underwent intra-arterial blood pressure and central hemodynamic measurements and NT-proBNP was determined in stored plasma. Baseline characteristics, plasma NT-proBNP concentrations and relevant laboratory variables were investigated for correlations with hemodynamic values using Spearman's rank correlation test. Results No significant correlations were demonstrated between NT-proBNP concentrations and variables associated with the severity of the pre-eclampsia. We found significant positive correlations between NT-proBNP and diastolic pulmonary pressure ( r = 0.59; p = 0.005) and pulmonary capillary wedge pressure (PCWP) ( r = 0.51; p = 0.015). Multiple linear regression analysis showed that the association between NT-proBNP and PCWP was not affected by creatinine level. Conclusion NT-proBNP is a biomarker of left ventricular cardiac filling pressures in untreated pre-eclamptic patients.

181 Predictors of mitral valve replacement after percutaneous mitral valvuloplasty

Percutaneous mitral valvuloplasty (PVM) is an effective therapy for mitral stenosis in selected patients. Nonetheless, mitral valve replacement (MVR) may be still required after PVM in some cases. The aim of this analysis is to assess predictors of MVR after PVM. Our retrospective study includes 354 patients enrolled in our department (1996-2002). Thirty seven (10, 34%) of 354 patients underwent MVR at a mean interval of 13,6±9,3 months after PVM. No major differences were apparent in the demographic features of patients who did or did not undergo surgery. Five patients (13%) underwent surgery within the first month after PVM while 32 patients (87%) were operated later. On univariate analysis several predictors were brought out: rheumatic antecedents, commissurotomy history, atrial fibrillation, severe mitral regurgitation before PVM or its aggravation after PVM, high echocardiography score, calcification, small mitral area, mitral gradient, diastolic and systolic arterial pulmonary pressure before PVM. However, on multivariate analysis only mitral area, diastolic and systolic arterial pulmonary pressure could be predictors for surgery. Certainly, PVM is an excellent treatment option in mitral stenosis. It is minimally invasive, well-tolerated and has a high success rate. But the need of surgery after PVM is not uncommon, so if a mitral valve restenosis occurred in patients with predictors of surgery, do we repeat PVM or directly perform RMV?

Abstract 2007: Effects of Myocardial Viability Assessed by Strain Stress Echocardiography on Diastolic Function in Acute Myocardial Infarction

Purpose: Myocardial viability may influence the diastolic function of left ventricle (LV) reflecting chamber remodeling in the early phase after acute myocardial infarction (AMI). However, the precise relationship in human has not been determined yet. So we aimed to evaluate whether myocardial viability assessed by strain rate parameters on low-dose dobutamine echocardiography (LD-DSE) may influence on LV diastolic function and remodeling process in AMI. Methods: In this prospective single center study, 134 consecutive patients with AMI and akinetic wall motion in at least two segments were enrolled and underwent LD-DSE on 5~9 days after the event. Myocardial viability was quantitatively evaluated by global peak systolic strain rate (psSR) and global time to peak of psSR. Within 6 hours after LD-DSE, left and right heart catheterization with the recording of LV end diastolic pressure and pulmonary capillary wedge pressure were performed. And then 6 months later, echocardiography and thallium scan with delayed image were followed. Results: Patients (67.9% men, mean age 60.1±1.1years, 54.5% anterior wall, 53.7% ST-segment elevation) were tolerated LD-DSE without significant complications. 71.6% of patients underwent revascularization therapy. After 6 months later, LV ejection fraction was significantly increased from 48.7±1.1% to 52.0±1.1% (p=0.00) and LV end diastolic volume was significantly decreased from 94.6±4.0cc to 89.1±3.8cc (p=0.00). As we expected, global psSR at baseline of LD-DSE showed significant linear correlations with LV end diastolic pressure, E/E’ ratio and left atrial volume index (r=−0.43 and p=0.01, r=0.52 and p=0.00 and r=0.52 and p=0.00, respectively). And also global psSR at 10mcg of LD-DSE correlated with E/E’ ratio and left atrial volume index(r=0.52 and p=0.00 and r=0.36 and p=0.02, respectively). Interestingly, global psSR at 10mcg of LD-DSE correlated significantly with the change of LV end diastolic volume during 6 months follow-up (r=−0.42 and p=0.04). Conclusions: Strain rate data on LD-DSE correlates with LV diastolic function in the early phase and chamber remodeling in 6 months follow-up after AMI. So strain stress echocardiography may provide useful prognostic information for LV remodeling in AMI.

Transcatheter closure of atrial septal defect with Amplatzer® device in children aged less than 10 years old: Immediate and late follow‐up

To analyze the efficacy and follow-up results of percutaneous closure of Atrial septal defect (ASD) with the Amplatzer septal occluder in children aged <10 years old. Between November 1998 and September 2005, 27 patients diagnosed with ASD were treated percutaneously with an Amplatzer septal occluder. The procedure was carried out in the cathlab, under general anesthesia and with both fluoroscopy and transesophageal echocardiography guidance. Basal physical examinations and echocardiograms were performed prior to the procedure and at 30 days, 6, and 12 months of follow-up. Survival free of symptom was estimated by Kaplan-Meier. The mean age, weight, height, body mass index, and corporal surface was: 5.35 +/- 2.11 years, 23.07 +/- 9.43 kg, 110.55 +/- 17.6 cm, 16.77 +/- 2.42 kg/m(2), and 1.24 +/- 2.44 m(2). The prevalence of septal aneurysm was 3.7% and all patients presented single secundum ASD. The mean stretched diameter by fluoroscopy and transesophageal echocardiography were 17.18 +/- 6.75 mm and 16.77 +/- 5.99 mm, and the prostheses sizes were 18.83 +/- 6.98 mm, ranging from 10 to 30 mm. The systolic and diastolic pulmonary pressures were 25.26 +/- 5.97 mm Hg and 13.38 +/- 3.40 mm Hg, respectively. The procedure time was 82.92 +/- 29.14 min and the hospital stay was 2.20 +/- 0.26 days. Clinical and echocardiography follow-ups were performed within 11.59 +/- 4.42 months and all devices were in the correct position with no residual shunt. Right ventricular diameter decreased from 19.38 +/- 5.23mm to 11.38 +/- 11.92 (P 0.001). No major complications or deaths occurred; two patients had a hematoma at the vascular access. Secundum atrial septal defect closure can be safely and successfully performed with the Amplatzer septal occluder in children younger than 10 years old.

Left ventricular assist device support normalizes left and right ventricular beta-adrenergic pathway properties

We hypothesized that some aspects of left ventricular assist device (LVAD) reverse remodeling could be independent of hemodynamic factors and would primarily depend upon normalization of neurohormonal milieu. The relative contributions of LVAD-induced hemodynamic unloading (provided to the left ventricle [LV]) and normalized neurohormonal milieu (provided to LV and right ventricle [RV]) to reverse remodeling are not understood. Structural and functional characteristics were measured from hearts of 65 medically managed transplant patients (MED), 30 patients supported with an LVAD, and 5 nonfailing donor hearts not suitable for transplantation. Compared with MED patients, diastolic pulmonary pressures trended lower (p < 0.01) and cardiac output higher (p < 0.001) in LVAD patients; V(30) (ex vivo ventricular volume yielding 30 mm Hg, an index of ventricular size) in LVAD patients was decreased in the LV (p < 0.05) but did not change significantly in RV. The LVAD support improved force generation in response to beta-adrenergic stimulation in isolated LV (increase in developed force from 6.3 +/- 0.6 to 18.5 +/- 4.4 mN/m(2), p < 0.01) and RV (increase in developed force, from 10.9 +/- 2.0 to 20.5 +/- 3.1 mN/m(2), p < 0.05) trabeculae. The LVAD patients had higher myocardial beta-adrenergic receptor density in LV (p < 0.01) and RV (p < 0.01). Protein kinase A (PKA) hyperphosphorylation of the ryanodine receptor 2 (RyR2)/calcium release channel was significantly reduced by LVAD in both RV and LV (p < 0.01). Improved beta-adrenergic responsiveness, normalization of the RyR2 PKA phosphorylation, and increased beta-adrenergic receptor density in LV and RV after LVAD support suggest a primary role of neurohormonal environment in determining reverse remodeling of the beta-adrenergic pathway.

Do Pulmonary Hemodynamics Change After Effective Lung Volume Reduction Surgery for Emphysema?

The improvement in lung function, exercise test, blood gas levels, and symptoms in emphysema patients after volume reduction surgery is a result of improvements in breathing mechanics. The question is, is the improvement in the condition related to pulmonary hemodynamics? Few studies have examined pre- and postoperative pulmonary pressure. This paper examines whether there is any significant change in systolic and diastolic pulmonary pressure after effective volume reduction surgery. From October 1999 to October 2002, 12 emphysema patients who underwent volume reduction surgery were studied. Systolic and diastolic pulmonary pressures were measured 2 days before surgery through cardiac catheterization and 2 days after removal of the chest tubes through Swan Ganz catheters placed in the operating room just before surgery. Patients were stable and breathed without assistance during the postoperative pressure measurement. Blood gas analysis, lung function tests, and a 6-minute walk test were performed preoperatively and 3 months postoperatively. The two sets of data were compared using the Wilcoxon signed rank test. There was no significant change in pulmonary hemodynamics, although pulmonary function improved. The improvement in pulmonary function after volume reduction surgery is not related to pulmonary hemodynamics.

Alterations of the Ventilation-Perfusion Ratio Measured by Using a Multiple Inert Gas Elimination Technique (MIGET) in One Lung Ventilated Rabbit

Background: In this study, we performed one-lung ventilation (OLV) in rabbits to assess the effects of OLV on the / ratio and the respiratory physiological changes using MIGET. Methods: Ten male New Zealand white rabbits, weighing 3-4 kg were selected. To perform MIGET, six inactive gases (SF, krypton, desflurane, enflurane, diethyl ether, acetone) in 500 ml normal saline were injected intravenously. During two-lung ventilation (TLV), and after OLV for 30 minutes, blood was sampled for blood gas analysis and MIGET, hemodynamic variables were measured. For MIGET, the concentrations of the injected inert gases were measured and converted to retention/excretion data; the / distribution curve was obtained using a computer. Results: Systolic, mean, and diastolic pulmonary pressures were elevated significantly and pulmonary resistance was doubled (P ＜ 0.05) in OLV compared to TLV. Blood pH decreased in OLV. The calculated intrapulmonary shunt was 19% and 52%, TLV and OLV, respectively. The analysis of / using MIGET showed that the / distribution curve was wider and that the / area was larger in normal rabbits. And, that intrapulmonary shunt approximated to 11%. In the case of OLV, a significant increase in shunt was observed but no change in the amount of dead space at distribution area, (log SD, log SD) remained the same, whereas the / distribution curve shifted toward the right. Conclusions: OLV in rabbits showed severe hypercapnia and hypoxemia leading to a considerable increase in shunt. Because of the wide range of / distribution in TLV, no significant changes in respiratory variables were observed during OLV.

Noninvasive estimation of both systolic and diastolic pulmonary artery pressure from Doppler analysis of tricuspid regurgitant velocity spectrum in patients with chronic heart failure

Background Noninvasive estimation of pulmonary artery systolic and diastolic pressures usually requires the investigation of both tricuspid and pulmonary regurgitant jets and an estimate of right atrial pressure. A new, noninvasive method to obtain pulmonary diastolic pressure (based on the hemodynamic demonstration that right ventricular systolic pressure and pulmonary artery diastolic pressure are equal at the time of pulmonary valve opening) from the analysis of tricuspid regurgitation alone has been described in a small cohort of patients. We sought to verify the accuracy of this method in a large population of patients with heart failure. Methods An estimate of pulmonary artery diastolic pressure was obtained by transposing the pulmonary opening time (from the onset of the R wave on the electrocardiographic tracing to the beginning of pulmonic forward flow on Doppler examination) onto the tricuspid regurgitant velocity curve and calculating the pulmonary artery diastolic pressure value as the pressure gradient between the right ventricle and right atrium at this time. The study group included 86 consecutive patients (64 men, aged 52 ± 11 years) with heart failure (New York Heart Association class ≥II, 94%) who were in stable clinical condition with a chiefly idiopathic (57%), ischemic (24%), or other form (13%) of dilated cardiomyopathy. Noninvasive, right-sided pressures were compared with invasive measurements obtained during right heart catheterization performed within 24 hours. The Bland and Altman graphic method was used together with the calculation of the Lin concordance correlation coefficient and its 95% CI to assess the agreement between hemodynamic and echocardiographic measurements. Results Catheter-derived pulmonary artery systolic pressure ranged from 8 to 119 mm Hg (mean 42 ± 21 mm Hg), pulmonary artery diastolic pressure from 1 to 59 mm Hg (mean 20 ± 11 mm Hg), and right atrial pressure from −5 to 20 mm Hg (mean 6 ± 5 mm Hg). Tricuspid regurgitation was detected in 75 of 86 patients (87%). Pulmonary artery systolic pressure ranged from 13 to 110 mm Hg (mean 44 ± 21 mm Hg); the pressure gradient between the right ventricle and right atrium at time t of the pulmonary valve opening on the tricuspid regurgitation velocity curve was measurable in 70 of 75 (93%) cases and ranged from 3.5 to 64 mm Hg (mean 22 ± 11 mm Hg). Good agreement was observed not only for pulmonary artery systolic pressure but also for pulmonary artery diastolic pressure, based on the analysis of the tricuspid regurgitation velocity jet, with a slight difference between measurements (−1.8 and 0.1, respectively), no evident pattern of point scattering, and a high concordance correlation coefficient that was elicited by the virtually total overlapping of lines on the graph. Overall results were not significantly different whether patients with depressed right ventricular function (right ventricular ejection fraction ≤35%), with a tricuspid regurgitation grade ≥2 and atrial fibrillation were included in the analysis. Conclusions The narrow paired difference for the estimate of pulmonary artery systolic pressure and the even better difference for pulmonary artery diastolic pressure using the tricuspid regurgitation velocity curve analysis indicates that this new method reliably estimates invasive right-sided pressures over a wide range of pressure values in patients with heart failure. The overall good correlation with invasive values indicates that Doppler examination of tricuspid regurgitation alone may provide a simple and comprehensive new method for the noninvasive evaluation of right ventricular and pulmonary hemodynamics in patients with heart failure. (Am Heart J 2002;144:1087-94.)

Effect of non-insulin-dependent diabetes mellitus on pulmonary function and exercise tolerance in chronic congestive heart failure

In chronic congestive heart failure (CHF), backward effects of left ventricular dysfunction alter pulmonary volumes and gas diffusion. Some of these disorders are detected in some patients with diabetes mellitus, possibly due to a microangiopathic process and nonenzymatic glycosylation of lung tissue proteins. We explored the possibility that coexistence of non-insulin-dependent diabetes mellitus (NIDDM) may potentiate the deterioration of lung function in CHF. In 20 normoglycemic patients (group 1) and in 20 patients with NIDDM (group 2), with New York Heart Association class II to III CHF due to idiopathic or ischemic cardiac disease, and in 20 controls (groups were age- and gender-matched), we investigated cardiac function, pulmonary volumes, carbon monoxide diffusion (DL CO) and its alveolar-capillary membrane (D M) subcomponent, oxygen uptake and dead space-to-tidal volume ratio (pVD/VT) at peak exercise (individualized ramp test), and slope of ventilation-to-carbon dioxide production ratio (VE/VCO 2) during exercise. Although, compared with reference subjects, both patient groups had similar variations in left ventricular diastolic volume, ejection fraction, and pulmonary wedge pressure; in group 2 lung volumes, DL CO, D M, and oxygen uptake were significantly more reduced; in this group there was no overlap of individual results of DL CO and D M with those in controls; VE/VCO 2 slope and pVD/VT also were significantly increased, and inversely correlated with D M. Thus, coexistence of NIDDM makes pulmonary dysfunction worse in CHF, and significantly enhances exercise intolerance.

Malignant hyperthermia phenotype: hypotension induced by succinylcholine in susceptible swine.

Succinylcholine causes immediate and severe arterial hypotension in swine with the malignant hyperthermia phenotype. The underlying mechanisms are unknown. Malignant hyperthermia-susceptible (MHS; n = 10) and normal swine (n = 5) were anesthetized with thiopental. The following were monitored: electrocardiogram; arterial blood pressure; pulmonary artery, central venous, and left and right ventricular pressure; cardiac output; end-tidal carbon dioxide; core temperature; peripheral-blood flows; and arterial blood gases. After a control period, 2 mg/kg succinylcholine was given intravenously. Three MHS animals received 1 mg/kg vecuronium and two MHS animals received 2.5 mg/kg dantrolene intravenously. The effects of succinylcholine on left and right ventricular pressure and contractility were analyzed in isolated hearts. The effects of 0.06 mm succinylcholine on isometric tension development were recorded in isolated femoral artery rings. Succinylcholine caused an early, severe decrease in blood pressure, cardiac output, left ventricular pressure, and left ventricular contractility in MHS swine but not in normal swine; no significant differences were found in heart rate, right ventricular parameters, systemic vascular resistance, and preload (pulmonary diastolic pressure, central venous pressure). The succinylcholine-induced hypotension and associated effects were not prevented by dantrolene. However, pretreatment with high-dose vecuronium prevented not only the cardiovascular depression, but also MH. In addition, no phenotypic differences of succinylcholine on contractility or left ventricular pressure were observed in the isolated working hearts. Similary, succinylcholine did not cause a significantly different relaxation in rings in either phenotype. Succinylcholine-induced hypotension occurred before muscle hypermetabolism in MHS swine. Succinylcholine had no differential physiologic effects on either the isolated heart or on isolated arteries. This hypotension could not be prevented by dantrolene but was prevented by pretreatment with high-dose vecuronium. Thus, an indirect mechanism such as the release of a cardiac depressant from skeletal muscle may have caused this hypotensive response.