Prospective Doppler echocardiographic evaluation of pulmonary artery diastolic pressure in the medical intensive care unit

The value of a dynamic echocardiographic approach to diastolic dysfunction in intensive care medicine

Diastolic dysfunction is an underestimated feature in the context of the critically ill setting and perioperative medicine. Advances in echocardiography, its noninvasive, safe and easy use, have allowed Doppler echocardiography to become a cornerstone for diagnosing diastolic dysfunction in clinical practice. The diagnosis of diastolic dysfunction and increased filling pressures is nevertheless complex. Using an echocardiographic assessment and the routine application of preload stress maneuvers during echocardiographic examination can help identify early stages of diastolic dysfunction leading to better management of patients at risk of acute heart decompensation in the perioperative period or during ICU stay.

Estimation of increased pulmonary wedge pressure by an algorithm based on noninvasively measured pulmonary diastolic pressure in cardiac patients independent of left ventricular ejection fraction

AIM

Pulmonary artery diastolic pressure (PADP) correlates closely with pulmonary wedge pressure (PAWP); therefore, we sought to evaluate whether an algorithm based on PADP assessment by the Doppler pulmonary regurgitation (PR) end-diastolic gradient (PRG) may aid in estimating increased PAWP in cardiac patients with reduced or preserved left ventricular (LV) ejection fraction (EF).

METHODS AND RESULTS

Right heart catheterization, with estimation of PAWP, right atrial pressure (RAP), PADP, and Doppler echocardiography, was carried out in 183 patients with coronary artery disease (n = 63), dilated cardiomyopathy (n = 52), or aortic stenosis (n = 68). One-hundred and seventeen patients had LV EF <50%. We measured the pressure gradients across the tricuspid and pulmonary valves from tricuspid regurgitation (TRV) and PR velocities. Doppler-estimated PADP (e-PADP) was obtained by adding the estimated RAP to PRG. An algorithm based on e-PADP to predict PAWP, that included TRV, left atrial volume index, and mitral E/A, was developed and validated in derivation (n = 90) and validation (n = 93) subgroups. Both invasive PADP (r = .92, P < .001) and e-PADP (r = .72, P < .001) correlated closely with PAWP, and e-PADP predicted PAWP (AUC: 0.85, CI: 0.79-0.91) with a 94% positive predictive value (PPV) and a 55% negative predictive value (NPV), after exclusion of five patients with precapillary pulmonary hypertension. The e-PADP-based algorithm predicted PAWP with higher accuracy (PPV = 94%; NPV = 67%; accuracy = 85%; kappa: 0.65, P < .001) than the ASE-EACVI 2016 recommendations (PPV = 97%; NPV = 47%; accuracy = 68% undetermined = 18.9%; kappa: 0.15, P < .001).

CONCLUSIONS

An algorithm based on noninvasively e-PADP can accurately predict increased PAWP in patients with cardiac disease and reduced or preserved LV EF.

Usefulness of the Continuous-Wave Doppler-Derived Pulmonary Arterial-Right Ventricular Pressure Gradient Just before Atrial Contraction for the Estimation of Pulmonary Arterial Diastolic and Wedge Pressures

In our new echocardiographic method, pulmonary regurgitant velocity immediately before right atrial (RA) contraction is used to estimate pulmonary artery diastolic pressure (PADP) and mean PA wedge pressure (MPAWP). Our aim here was to compare the usefulness of this new method with that of the conventional method, which uses pulmonary regurgitant velocity at end diastole. We studied 55 consecutive patients who underwent echocardiography and right-sided heart catheterization. The pulmonary regurgitant velocities just before RA contraction and at end diastole were measured to obtain echocardiographic estimates of PADP (EPADP_preA and EPADP_ED, respectively) by adding the pressure gradients to the echocardiographically estimated RA pressure. Compared with EPADP_ED, EPADP_preA correlated better with PADP (r = 0.87) and MPAWP (r = 0.80), and direct fixed biases were detected for EPADP_ED but not for EPADP_preA. The area under the receiver operating characteristic curve distinguishing patients with MPAWP ≥18 mm Hg was greater for EPADP_preA (0.97) than for E/e' (0.94) and E/A (0.83). EPADP_preA is thus useful in estimating PADP and MPAWP in patients with heart disease.

Impact of Elevated End-Diastolic Pulmonary Regurgitation Gradient on Worse Clinical Outcomes in Hospitalized Patients With Heart Failure

The echo Doppler end-diastolic pulmonary regurgitation (EDPR) gradient correlates well with catheter-derived pulmonary artery diastolic pressure. An elevated EDPR gradient is associated with worse clinical outcomes in patients with stable coronary artery disease. However, the prognostic significance of EDPR gradient in patients with heart failure (HF) is unclear. The aim of the present study was to investigate the prognostic impact of EDPR gradient in HF. We retrospectively examined 751 consecutive hospitalized patients with acute HF. Those with acute coronary syndrome or in-hospital death and those without accessible EDPR gradient data at discharge were excluded. Finally, 265 patients were examined and divided into 2 groups according to EDPR gradient (cutoff 9 mm Hg). Adverse events were defined as worsening HF and death. Patients with elevated EDPR gradient had higher B-type natriuretic peptide, lower age, and lower left ventricular ejection fraction at discharge than those with nonelevated EDPR gradient. During a median follow-up of 429 days, elevated EDPR gradient was independently associated with adverse events (hazard ratio 2.34, 95% CI 1.44 to 3.78, p <0.001) after adjustment for confounders. In conclusion, echo Doppler EDPR gradient might be a noninvasive predictor of clinical outcomes in hospitalized patients with HF.

A new method to estimate pulmonary vascular resistance using diastolic pulmonary artery-right ventricular pressure gradients derived from continuous-wave Doppler velocity measurements of pulmonary regurgitation

Pulmonary vascular resistance (PVR) is an important hemodynamic parameter in patients with heart failure, especially when the pulmonary arterial pressure is lower due to reduced stroke volume. Several echocardiographic methods to estimate PVR have been proposed, but their applications in patients with organic left-sided heart diseases have been limited. The aim of the present study was to examine the usefulness of our new method to estimate PVR (PVR_PR) based on the continuous-wave Doppler velocity measurements of pulmonary regurgitation in these patients. In 43 patients who underwent right heart catheterization, PVR_PR was calculated as the difference between the Doppler-derived early- and end-diastolic pulmonary artery (PA)-right ventricular (RV) pressure gradients divided by the cardiac output measured in the left ventricular outflow tract by echocardiography. The PVR_PR correlated well with invasive PVR (PVR_CATH) (r = 0.81, p < 0.001) without any fixed bias in Bland-Altman analysis. The conventional echocardiographic PVRs showed inadequate correlations with PVR_CATH, or a obvious overestimation of PVR_CATH. In the receiver operating characteristic analyses to determine the patients with abnormal elevation of PVR_CATH (>3 Wood units, WU), the area under the curve was the greatest for PVR_PR (0.964) compared to the conventional PVRs (0.649-0.839). PVR_PR had 83 % sensitivity and 100 % specificity at the optimal cut-off value of 3.10 WU in identifying patients with PVR_CATH >3 WU. Our simple and theoretical PVR_PR is useful for the noninvasive estimation of PVR.

The right ventricle under pressure: evaluating the adaptive and maladaptive changes in the right ventricle in pulmonary arterial hypertension using echocardiography (2013 Grover Conference series)

The importance of the right ventricle (RV) in pulmonary arterial hypertension (PAH) has been gaining increased recognition. This has included a reconceptualization of the RV as part of an RV-pulmonary circulation interrelated unit and the observation that RV function is a major determinant of prognosis in PAH. Noninvasive imaging of RV size and function is critical to the longitudinal management of patients with PAH, and continued understanding of the pathophysiology of pulmonary vascular disease relies on the response of the RV to pulmonary vascular remodeling. Echocardiography, in particular the newer echocardiographic measurements and techniques, allows easy, readily accessible means to assess and follow RV size and function.

Differences in hemodynamic responses between intravenous carperitide and nicorandil in patients with acute heart failure syndromes

While recent guidelines for the treatment of acute heart failure syndromes (AHFS) recommend pharmacotherapy with vasodilators in patients without excessively low blood pressure (BP), few reports have compared the relative efficiency of vasodilators on hemodynamics in AHFS patients. The present study aimed to assess the differences in hemodynamic responses between intravenous carperitide and nicorandil in patients with AHFS. Thirty-eight consecutive patients were assigned to receive 48-h continuous infusion of carperitide (n = 19; 0.0125-0.05 μg/kg/min) or nicorandil (n = 19; 0.05-0.2 mg/kg/h). Hemodynamic parameters were estimated at baseline, and 2, 24, and 48 h after drug administration using echocardiography. After 48 h of infusion, systolic BP was significantly more decreased in the carperitide group compared with that in the nicorandil group (22.1 ± 20.0 % vs 5.3 ± 10.4 %, P = 0.003). While both carperitide and nicorandil significantly improved hemodynamic parameters, improvement of estimated pulmonary capillary wedge pressure was greater in the carperitide group (38.2 ± 14.5 % vs 26.5 ± 18.3 %, P = 0.036), and improvement of estimated cardiac output was superior in the nicorandil group (52.1 ± 33.5 % vs 11.4 ± 36.9 %, P = 0.001). Urine output for 48 h was greater in the carperitide group, but not to a statistically significant degree (4203 ± 1542 vs 3627 ± 1074 ml, P = 0.189). Carperitide and nicorandil were differentially effective in improving hemodynamics in AHFS patients. This knowledge may enable physicians in emergency wards to treat and manage patients with AHFS more effectively and safely.

Noninvasive estimation of diastolic pulmonary artery pressure by Doppler analysis of tricuspid regurgitation velocity in pediatric patients

PURPOSE

Diastolic pulmonary artery pressure (dPAP) is equal to right ventricular pressure at the time of pulmonary valve opening. We studied the accuracy of dPAP estimated from Doppler profile of tricuspid regurgitation (TR) jet in pediatric patients.

METHODS

Echocardiograms were prospectively performed on consecutive pediatric heart transplant recipients undergoing right-heart catheterization and endomyocardial biopsy. An estimate of dPAP was obtained by superimposing the pulmonary valve opening time, indexed to the electrocardiogram, onto the TR Doppler tracing. Echocardiographic estimates of dPAP from end-diastolic pulmonary regurgitation (PR) were obtained for comparison. Catheter-derived right atrial pressure was added to the Doppler gradient in both groups. Doppler estimates and catheter-derived measurements of dPAP were compared using Lin correlation and Bland-Altman analysis.

RESULTS

Sixty-five catheterization studies were performed on 35 patients (20 males): median age at enrollment: 12.1 years (4 months to 18 years); median time: since transplant of 1.2 years (21 days to 16.1 years). Adequate TR signal was obtained in a significantly higher proportion of patients than an adequate PR signal (65% vs. 43%, respectively, P = .007). Median catheter-derived dPAP was 12 mm Hg (6-30 mm Hg) and right atrial pressure was 6 mm Hg (1-17 mm Hg). Median estimated dPAP from TR was 15 mm Hg (range: 7-29 mm Hg), with the Lin correlation coefficient of 0.74 (95% confidence interval [CI]: 0.6-0.87). Median estimate for dPAP from PR was 10 mm Hg (range: 2-25 mm Hg), with the Lin correlation coefficient of 0.74 (95% CI: 0.58-0.9). There was excellent interobserver agreement for dPAP from TR with the Lin correlation coefficient of 0.946 (95% CI: 0.803-0.986).

CONCLUSION

Doppler estimation of dPAP from TR is a novel, reliable, noninvasive method and compares favorably with estimation from PR. Adequate TR signal for estimation of dPAP can be obtained more frequently in children than adequate PR signal, thereby increasing the proportion of patients in whom dPAP can be estimated noninvasively.

[Echocardiography in the Intensive Care Unit]

The echocardiography can provide important and relevant information and the critically ill patient presents a challenge for the echocardiographer: from limitations in image acquisition to interpretation in the context of rapid physiological and intervention changes. The most frequent reason for requesting an echocardiogram in the ICU is probably to assess left ventricular function. In any case, information of direct relevance for clinical management can in relationship to abnormalities of structure and function can be obtained and used to estimate pulmonary arterial and venous pressures. It can help to investigate the consequences of myocardial ischemia, valvular dysfunction and pericardial disease and detect changes characteristic of specific conditions (e.g. sepsis, pulmonary thromboembolism), although this must be interpreted in the context of each individual patient. The echocardiography also can be used to monitor the therapeutic interventions. The applications of echocardiography in the critical care setting are reviewed, with special emphasis on the assessment of cardiac physiology.

Heart failure: hemodynamic assessment using echocardiography

Hemodynamics play a crucial role in diagnosing and managing heart failure (HF) as diagnostic markers and therapeutic targets. In an era of declining physical examination skills and questions about the safety of invasive monitoring, quantitative, objective data provided by echo-Doppler measurements can function as a type of "echo Swan-Ganz catheter" as an important adjustment to traditional methods of hemodynamic assessment. Echocardiographic measures of right- and left-sided filling pressures, pulmonary vascular resistance, and cardiac output are possible in many (although not all) HF patients. Recent studies suggest these measurements can have an important role in clinical pathways treating patients admitted with decompensated HF. The availability of miniaturized echocardiographic devices with full echo-Doppler capability may make repeatable, noninvasive hemodynamic assessment readily available and cost-effective for patients in many clinical settings.

Estimation of Pulmonary Vascular Resistance with Doppler Diastolic Gradients

This study was undertaken to determine the diastolic Doppler echocardiographic correlates of pulmonary vascular resistance calculated on cardiac catheterization in patients with secondary pulmonary arterial hypertension. Thirty-eight consecutive patients with congenital heart disease, pulmonary artery hypertension and pulmonary regurgitation were studied. Continuous-wave Doppler-derived pulmonary artery diastolic gradients were measured at 3 points on the pulmonary regurgitant diastolic velocity slope: peak diastolic, end-diastolic (at the R wave on the electrocardiogram), and mid-diastolic (midway between the peak and end-diastolic points). Catheterization data included oximetry, measurements of pressure in the cardiac chambers and great arteries, and calculation of pulmonary vascular resistance index. Doppler-derived peak, mid, and end-diastolic pulmonary regurgitation gradients correlated best with catheterization-measured pulmonary artery systolic, mean and diastolic pressures, respectively. The best Doppler correlate of pulmonary vascular resistance index was the pulmonary artery end-diastolic gradient. Clinically useful information can be obtained from Doppler pulmonary artery diastolic gradients measured on the pulmonary regurgitant diastolic velocity slope, which can estimate the pulmonary arterial pressure as well as pulmonary vascular resistance obtained on cardiac catheterization.

Future potential of echocardiography in heart failure

Echocardiography represents a convenient, portable and noninvasive method to provide important anatomic and physiologic information to inform the management of heart failure patients. Traditional echo assessments include diagnostic, etiologic and prognostic data from ventricular size, geometry and performance. Newer echocardiographic techniques are receiving greater utilization, however, and promise to further enhance diagnostic abilities in heart failure. This article reviews traditional anatomic assessments, echo-based cardiac hemodynamics, 3D echocardiography, quantification of myocardial tissue mechanics and hand-carried echocardiography. These developments in echocardiography underlie future trends toward echo objectivity, improved imaging of patients with poor acoustic windows, miniaturization and simplicity in focused exams and the expanded application of old and new techniques.

Imaging studies in patients with heart failure: current and evolving technologies

Technological advances continue to expand the clinical role of echocardiography in the intensive care unit, particularly in patients with heart failure. It has many advantages over tomographic techniques such as echo cardiac magnetic resonance imaging and cardiac computed tomography, can provide rapid bedside cardiac assessment, and facilitate emergent decision-making for critically ill patients. Image quality problems in the intensive care setting have largely been overcome by the use of harmonic imaging, contrast opacification, and when indicated, transesophageal echocardiography. Newer techniques promise to advance the scope and prognostic power of echocardiography, and to expand the portability and availability of this tool.

C-reactive protein, diastolic dysfunction, and risk of heart failure in patients with coronary disease: Heart and Soul Study

BACKGROUND

High-sensitivity C-reactive protein (CRP) is an inflammatory marker that predicts coronary heart disease (CHD) and, in recent studies, incident heart failure (HF). Whether the association of inflammation with incident HF is explained by worse baseline left ventricular dysfunction or by underlying CHD is unknown.

METHODS AND RESULTS

Serum CRP was measured in a cohort of 985 outpatients with established CHD from the Heart and Soul Study. During 3 years of follow-up, 15% of the participants with elevated CRP levels (>3 mg/L) were hospitalised for HF, compared with 7% of those with CRP <or= 3 mg/L. In multivariate analysis, elevated CRP was associated with HF after adjustment for traditional risk factors, baseline CHD severity and interim MI (adjusted HR 2.1, 95% CI, 1.2-3.6; p=0.009). However, elevated CRP was no longer associated with HF after further adjustment for the presence of diastolic dysfunction on echocardiography (adjusted HR 1.6, 95% CI, 0.8-3.2; p=0.1).

CONCLUSIONS

Among outpatients with stable CHD, elevated CRP levels predict hospitalisation for heart failure, independent of baseline heart failure, medication use, CHD severity, and subsequent MI events. This relationship appears to be at least partly explained by abnormal diastolic function in patients with elevated CRP levels.

Quantitative assessment of pulmonary insufficiency by Doppler echocardiography in patients with adult congenital heart disease

We determined the utility of continuous wave (CW) Doppler for quantification of pulmonary insufficiency (PI) confirmed by pulmonary angiography in patients with postoperative adult congenital heart disease. A total of 41 patients with PI were divided into two groups on the basis of PI severity by pulmonary angiography: group A (n = 27) with severe PI and group B (n = 14) with mild or moderate PI. Nine patients in group A had pulmonic valve replacement and reverted to mild PI after surgery. Their pre- and postoperative data were compared. All underwent a two-dimensional/Doppler study with interrogation of the PI jet for jet width by color Doppler and peak flow velocity, deceleration time (DT), pressure half-time (PHT), diastolic period (DP), and PI flow time (FT) by CW Doppler. The no-flow time (NFT), NFT/FT ratio, and NFT/DP fraction were calculated. Group A had a larger right ventricle (4.1 +/- 0.9 vs. 3.5 +/- 0.6 cm, P = .033), higher PI peak velocity (2.1 +/- 0.5 vs. 1.7 +/- 0.5 m/s, P = .04), shorter DT (261 +/- 61 vs. 317 +/- 83 ms, P = .018) and PHT (76 +/- 29 vs. 132 +/- 53, P < .0001), longer NFT (146 +/- 66 vs. 40 +/- 42 ms, P < .0001), and higher ratios of NFT/FT (46% +/- 27% vs. 13% +/- 14%, P < .0001) and NFT/DP (29% +/- 13% vs. 10% +/- 9%, P < .0001). The PHT and DT lengthened, and the NFT shortened in patients who underwent pulmonic valve replacement (all P < .05). By binary logistic regression, NFT and PHT were the best predictors for severe PI. An NFT of 80 ms had 84% sensitivity and 93% specificity, and a PHT of 100 ms had 93% sensitivity and 93% specificity for identifying angiographically severe PI. CW Doppler accurately distinguishes severe from lesser degrees of PI in patients with postoperative adult congenital heart disease.

Association of African American race with elevated pulmonary artery diastolic pressure: data from the Heart and Soul Study

BACKGROUND

Whether increased severity of heart failure in African Americans is a result of differences in cardiac physiology is uncertain. The end-diastolic pulmonary regurgitation (EDPR) gradient is associated with abnormal cardiac physiology. We hypothesized that African American race is associated with an elevated EDPR gradient that may partially predispose African Americans to heart failure.

METHODS

The Heart and Soul Study prospectively assessed the EDPR gradient in 480 patients with coronary disease. We used multivariable linear regression to investigate the independent association of African American race with EDPR gradient.

RESULTS

Compared with 393 non-African Americans, the 87 African Americans had similar indices of left ventricular systolic and diastolic function, left ventricular mass index, mitral regurgitation, peak tricuspid regurgitation gradient, and pulmonary velocity time integral. However, the EDPR gradient was significantly higher in African Americans (4.2 +/- 3.3 mm Hg) than in Caucasians (3.1 +/- 2.5 mm Hg) or other racial groups (3.5 +/- 2.7 mm Hg) (P = .008). In a multivariable model, African American race was a significant predictor of elevated EDPR gradient (beta coefficient 0.75, P = .03).

CONCLUSION

African American race is independently associated with an elevated EDPR gradient in patients with coronary artery disease.

Bedside echocardiography in the assessment of the critically ill

Advances in ultrasound technology continue to enhance its diagnostic applications in daily medical practice. Bedside echocardiographic examination has become useful to properly trained cardiologists, anesthesiologists, intensivists, surgeons, and emergency room physicians. Cardiac ultrasound can permit rapid, accurate, and noninvasive diagnosis of a broad range of acute cardiovascular pathologies. Although transesophageal echocardiography was once the principal diagnostic approach using ultrasound to evaluate intensive care unit patients, advances in ultrasound imaging, including harmonic imaging, digital acquisition, and contrast for endocardial enhancement, has improved the diagnostic yield of transthoracic echocardiography. Ultrasound devices continue to become more portable, and hand-carried devices are now readily available for bedside applications. This article discusses the application of bedside echocardiography in the intensive care unit. The emphasis is on echocardiography and cardiovascular diagnostics, specifically on goal-directed bedside cardiac ultrasonography.

Echocardiographic Assessment of Right Heart Hemodynamic Parameters

Echocardiography is currently the primary clinical method for the noninvasive measurement of right heart hemodynamic parameters and is an indispensable tool for the initial assessment, diagnosis, longitudinal follow-up, and prognostication of patients with abnormal right heart function. This review will discuss the echocardiographic methods used to estimate right heart hemodynamic parameters.

Pulmonary Hemodynamic Effects of Dipyridamole Infusion in Patients with Normal and Elevated Pulmonary Artery Systolic Pressure Receiving PB127

BACKGROUND

Intravenous administration of microspheres used as ultrasound contrast agents may potentially alter pulmonary hemodynamics. PB127 (POINT Biomedical Corp., San Carlos, CA) is an investigational ultrasound perfusion-imaging agent used in conjunction with dipyridamole to diagnose coronary artery disease. The effects of PB127 alone or in combination with dipyridamole on pulmonary hemodynamics have not been described.

METHODS

We studied 20 patients, including 10 with elevated screening pulmonary artery systolic pressure (>35 mm Hg). Doppler-derived pulmonary hemodynamics were determined before and after continuous infusion of PB127 (0.175 mg/kg diluted in 5% dextrose) or 5% dextrose. Patients then received dipyridamole (0.56 mg/kg) and hemodynamics were again assessed.

RESULTS

During PB127/dextrose infusion, there were no significant changes in pulmonary hemodynamics compared with baseline. After dipyridamole, there were small increases in pulmonary artery systolic pressure and in pulmonary flow and a reduction in pulmonary vascular resistance. These changes occurred in patients with normal and elevated pulmonary artery systolic pressure.

CONCLUSION

PB127 infusion does not alter pulmonary hemodynamics. Mild alterations of pulmonary hemodynamics occur after dipyridamole administration.

A Novel Echocardiographic Doppler Method for Estimation of Pulmonary Arterial Pressures

BACKGROUND

Current noninvasive methods for estimating diastolic and mean pulmonary artery pressures (PAp) in children are cumbersome and have limited accuracy. We hypothesized that systolic PAp correlates with diastolic and mean PAp, and that this correlation can be used to estimate diastolic and mean PAp from Doppler flow data.

METHODS

We recorded PAp in 112 patients 30 years or younger catheterized for heart failure, heart transplant, pulmonary hypertension, or congenital heart disease. We derived the relationship of systolic PAp to diastolic and mean PAp. We then applied these relations to systolic PAp measured by tricuspid regurgitation (TR) Doppler flow in a subset of 17 patients with pulmonary hypertension to predict mean and diastolic PAp, and correlated the results.

RESULTS

An excellent linear relation was found between systolic PAp and both the diastolic and mean PAp measured at cardiac catheterization (r = 0.95, P < .0001; r = 0.98, P < .0001, respectively). The calculated diastolic PAp calculated from TR Doppler correlated well with invasive data (31 +/- 13 vs 30 +/- 11 mm Hg, respectively, not significant; r = 0.85, P < .0001) and surpassed existing methods that are based on pulmonary regurgitation for predicting diastolic PAp. Similarly, mean PAp calculated from TR Doppler flow correlated well with invasive data (r = 0.86, P < .0001).

CONCLUSION

A strong linear relationship between systolic and diastolic PAp allows for easy and accurate noninvasive estimation of diastolic and mean PAp from TR Doppler flow.

Pulmonary regurgitation end-diastolic gradient is a Doppler marker of cardiac status: data from the Heart and Soul Study

BACKGROUND

Echocardiograms routinely sample pulmonary regurgitation signals from which it is possible to measure end diastolic gradients; these correlate with pulmonary artery diastolic pressures.

METHODS

We performed echocardiograms in 741 ambulatory adults with coronary artery disease who were recruited for the Heart and Soul Study. We compared indicators of cardiac status among individuals with normal (0-5.0 mm Hg) and elevated (> 5.0 mm Hg) end diastolic pulmonary regurgitation (EDPR) gradients.

RESULTS

Of the 481 participants with measurable EDPR gradients, 21% had elevated EDPR gradients (> 5.0 mm Hg). EDPR gradients > 5.0 mm Hg were associated with higher New York Heart Association functional class (P = .002), higher brain natriuretic peptide (P = .002), fewer metabolic equivalents achieved on treadmill testing (P < 0.001), and higher left ventricular mass (P < 0.001). The EDPR gradient > 5.0 mm Hg had a sensitivity of 25% (95% confidence interval 20-30%) and a specificity of 86% (80-91%) for detecting at least one of the following: systolic dysfunction, diastolic dysfunction, or abnormal wall motion score. The EDPR gradient > 5.0 mm HG was statistically equivalent to the tricuspid regurgitation (TR) gradient > 30 mm Hg in terms of diagnostic value (area under the receiver operating characteristic curve equaled 0.58 for each test). The EDPR gradient increased the yield of pulmonary artery pressures from 61% (TR gradient alone) to 84% (P < .0001).

CONCLUSION

The EDPR gradient provides valuable information independent of the TR gradient in evaluating pulmonary artery pressures and cardiac dysfunction.

Two simple echo-Doppler measurements can accurately identify pulmonary hypertension in the large majority of patients with chronic heart failure

BACKGROUND

The assessment of pulmonary hypertension in patients with heart failure is of great clinical importance not only for diagnostic purposes but also for prognostication. The present study was undertaken on a consecutive basis with a group of patients with chronic heart failure. Patients were evaluated for their suitability for heart transplantation: (1) to explore the diagnostic accuracy of several echo Doppler parameters of pulmonary hemodynamics in predicting the presence of elevated pulmonary artery pressure (defined as pulmonary artery systolic pressure > or =35 mmHg and mean pulmonary artery pressure >20 mmHg); (2) to assess the diagnostic ability of the same parameters to identify patients with elevated pulmonary vascular resistance; and (3) to evaluate the influence of right ventricular function and degree of tricuspid regurgitation in modifying diagnostic accuracy.

METHODS

Echo Doppler examination and right heart catheterization were performed consecutively within 24 hours in 86 patients. The optimal cut-off value for a series of echo Doppler parameters capable of identifying patients with pulmonary hypertension was obtained by dividing the entire sample into 2 groups; the optimal threshold (highest sensitivity and specificity) of the echo and Doppler parameters used to classify patients with and without pulmonary hypertension was determined in 67% of cases by means of the receiver operating characteristic (ROC) curve: this was the testing sample. The proportion of cases classified correctly according to the selected cut-off was computed. The remaining 33% of cases represented the validation sample: sensitivity, specificity and predictive values (and their 95% confidence intervals [CIs]) for identifying pulmonary hypertension were calculated from the proposed cut-offs in this second sample. Finally, the overall performance of the echo Doppler parameters was assessed over the whole sample by considering the extent of the area under the ROC curve (A-ROC) and its 95% CI, for the dichotomic measurement.

RESULTS

On right heart catheterization, a pulmonary artery systolic (PAPs) pressure > or =35 mmHg plus a mean pressure (mean PAP) >20 mmHg was documented in 49 of 86 cases (57%), for whom mean values were 56 +/- 17 and 38 +/- 11 mmHg, respectively. The proportion of cases identified correctly as having pulmonary hypertension was highest for PAPs (88%) and mean PAP (85%) in addition to acceleration time of pulmonary artery systolic flow (ACT) (79%) and pulmonary artery diastolic pressure obtained utilizing the early phase of the tricuspid regurgitation spectral flow (PAPd/TR) (75%). PAPd/TR performed better in the validating sample in terms of diagnostic ability, with high sensitivity and specificity (100% and 60%) and positive and negative predictive values (PPV 80%, NPV 100%). PAPs, mean PAP, ACT and PAPd/TR confirmed their prevailing diagnostic ability (A-ROC from 0.74 to 0.86) in identifying pulmonary hypertension with fair to high feasibility (67% to 91%) and an odds ratio (OR) indicative of strong association. ACT and PAPd/TR, the 2 parameters with the highest feasibility, allowed us to identify 46 of 49 (94%) hypertensive cases. The same parameters did not perform well in identifying patients with increased vascular resistance, with A-ROC ranging from 0.55 to 0.69. Heterogeneity of effect, due to right ventricular function or tricuspid regurgitation degree, could not be demonstrated in the ability of the echo Doppler measurements to identify pulmonary hypertension.

CONCLUSIONS

ACT, PAPd/TR, PAPs and mean PAP have been shown to accurately classify patients with chronic heart failure with or without pulmonary hypertension. In particular, ACT and PAPd/TR alone allowed reliable and accurate definition of pulmonary hypertension in 94% of patients, regardless of right ventricular function or degree of tricuspid regurgitation. Non-invasive pulmonary pressure assessment by the referred method might be useful in the evaluation of heart transplant candidates.

Bedside ultrasonography in the ICU: part 1

Ultrasonography has become an invaluable tool in the management of critically ill patients. Its safety and portability allow for use at the bedside to provide rapid, detailed information regarding the cardiovascular system and the function and anatomy of certain internal organs. Echocardiography can noninvasively elucidate cardiac function and structure. This information is vital in the management hemodynamically unstable patients in the ICU. In addition, ultrasonography has particular value for the assessment and safe drainage of pleural and intra-abdominal fluid and the placement of central venous catheters. A new generation of portable, battery-powered, inexpensive, hand-carried ultrasound devices have recently become available; these devices can provide immediate diagnostic information not assessable by physical examination alone and allow for ultrasound-guided thoracocentesis, paracentesis, and central venous cannulation. This two-part article reviews the application of bedside ultrasonography in the ICU.

Clinical efficacy of sildenafil in primary pulmonary hypertension

OBJECTIVES

In a randomized, double-blind, crossover design, we compared the efficacy of sildenafil with placebo in patients with primary pulmonary hypertension (PPH). The primary end point was the change in exercise time on treadmill using the Naughton protocol. Secondary end points were change in cardiac index and pulmonary artery systolic pressure as assessed by Doppler echocardiography and quality of life (QOL) as assessed by a questionnaire.

BACKGROUND

Primary pulmonary hypertension is a disorder with limited treatment options. Uncontrolled studies had shown sildenafil to be beneficial in the treatment of PPH.

METHODS

After initial clinical evaluation, including Doppler echocardiography and treadmill exercise test, patients were randomized to placebo or sildenafil with dosages ranging from 25 to 100 mg thrice daily on the basis of body weight. The evaluation was repeated after six weeks. Then patients were crossed over to alternate therapy. Final evaluation was performed after another six weeks of treatment.

RESULTS

Twenty-two patients completed the study. Exercise time increased by 44% from 475 +/- 168 s at the end of placebo phase to 686 +/- 224 s at the end of sildenafil phase (p < 0.0001). With sildenafil, cardiac index improved from 2.80 +/- 0.9 l/m2 to 3.45 +/- 1.1 l/m(2) (p < 0.0001), whereas pulmonary artery systolic pressure decreased insignificantly from 105.23 +/- 17.82 mm Hg to 98.50 +/- 24.38 mm Hg. There was significant improvement in the dyspnea and fatigue components of the QOL questionnaire. During the placebo phase, one patient died and another had syncope. There were no serious side effects with sildenafil.

CONCLUSIONS

Sildenafil significantly improves exercise tolerance, cardiac index, and QOL in patients with PPH.

Comparison of canine heartworm removal rates using flexible alligator forceps guided by transesophageal echocardiography and fluoroscopy

Fluoroscopy (FS)- or transesophageal echocardiography (TEE)-guided heartworm removal was carried out using flexible alligator forceps to compare the rate of worm removal. As a result, the worm removal rates were similar between the two procedures. However, the TEE-guided procedure does not involve radiation exposure, and facilitates observation of worms in the cardiac chamber and pulmonary artery. Therefore, the TEE-guided procedure is thought to be more useful than the FS-guided procedure in clinical setting.

Contrast-enhanced Doppler hemodynamics for noninvasive assessment of patients with chronic heart failure and left ventricular systolic dysfunction

We sought to evaluate whether contrast-enhanced Doppler echocardiography can improve the noninvasive estimation of hemodynamic variables in left ventricular (LV) dysfunction. Right-heart catheterization and Doppler echocardiography were simultaneously performed in 45 patients with LV dysfunction (ejection fraction: 29 +/- 7%) in sinus rhythm. Noninvasive variables were estimated as follows: cardiac output by pulsed Doppler of LV outflow tract; pulmonary capillary wedge pressure by a regression equation including mitral and pulmonary venous flow variables; pulmonary artery mean pressure from the calculated systolic and diastolic pulmonary artery pressures; and pulmonary vascular resistance from the previous measurements according to hemodynamic definition. Contrast enhancement increased the feasibility of pulmonary capillary wedge pressure estimation from 60% to 100%; of pulmonary artery mean pressure from 42% to 91%; and of pulmonary vascular resistance from 42% to 91%. Strong correlations between invasive and noninvasive hemodynamic variables were found: r = 0.90, standard error of the estimate (SEE) 0.45 L/min for cardiac output; r = 0.90, SEE 3.1 mm Hg for pulmonary capillary wedge pressure; r = 0.93, SEE 3.7 mm Hg for pulmonary artery mean pressure; and r = 0.85 SEE 1.0 Wood units for pulmonary vascular resistance. Weaker correlations for PAMP (r = 0.82, SEE 5.6 mm Hg) and PVR (r = 0.66, SEE 1.7 Wood units) were apparent prior to contrast enhancement. When patients were separated according to PVR threshold values, the contrast allowed the correct placement of 88% of patients, whereas only 57% were correctly assigned without it. The contrast increased accuracy and reduced interobserver variability in the evaluation of hemodynamic variables. The contrast-enhanced study is capable of increasing the value of noninvasive hemodynamic assessment in LV dysfunction.

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 > or =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 < or =35%), with a tricuspid regurgitation grade > or =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.

Continuous recording of pulmonary artery diastolic pressure and cardiac output using a novel ultrasound transducer

BACKGROUND

The feasibility of hands-free transthoracic continuous determination of pulmonary artery (PA) diastolic pressure (PAD) and cardiac output (CO) by Doppler ultrasound has not been previously demonstrated. We developed a 2.5-MHz spherical transducer mounted in an external housing to permit steering in 360 degrees (Contison). The external housing was attached to the chest wall using an adhesive patch.

METHODS AND RESULTS

Fifty patients in the coronary care department who had PA catheters had Doppler ultrasound studies. The 2.5-MHz spherical transducer was placed at the left sternal border to permit imaging of the pulmonic valve and was attached to a commercial ultrasound machine. The PA was imaged and its diameter measured. The pulmonary flow velocity signal was recorded and the time velocity integral obtained. The CO was calculated as: CO = time velocity integral of the PA systolic flow velocity signal x pi diameter(2) divided by 4 x heart rate. The pulmonary regurgitation signal was then recorded and the end-diastolic velocity of the regurgitant signal was measured. Right atrial pressure was assessed from the jugular venous pressure or from the size and pulsatility of the inferior vena cava. The PADP was calculated as: PADP = 4 end-diastolic velocity of the regurgitant signal(2) + right atrial pressure. The CO, PADP, and pulmonary wedge pressure were recorded from the PA catheter immediately after the ultrasound studies. Serial data were obtained every half hour or 1 hour up to a maximum of 5 hours. Adequate Doppler signals were obtained in 43 patients.

RESULTS

There was a good correlation between the PADP by Doppler versus PA catheter (r = 0.90, standard error of the estimate = 3.3 mm Hg); PADP by Doppler versus PA wedge pressure (r = 0.88, standard error of the estimate = 3.7 mm Hg); and CO by Doppler versus PA catheter (r = 0.92, standard error of the estimate = 0.7 L/min).

CONCLUSION

The 2.5-MHz spherical transducer permitted accurate assessment of CO and PAD. This transducer could be of potential value in monitoring patients in the intensive care setting.

The use of echocardiography in the critical care setting

Echocardiography has become an invaluable tool in the management of critically ill patients. Its safety and portability allow for use at the bedside to provide rapid, detailed information regarding the cardiovascular system. Echocardiography can elucidate cardiac structure and mechanical function. Recently, the power of clinical echocardiography has been augmented by the use of Doppler techniques to evaluate cardiovascular hemodynamics. An in-depth understanding of the proper use of echocardiography is a prerequisite for the intensivist.

Noninvasive estimation of pulmonary artery diastolic pressure in patients with tricuspid regurgitation by Doppler echocardiography

OBJECTIVES

The purpose of this study was to determine whether Doppler echocardiographic assessment of right ventricular pressure at the time of pulmonary valve opening could predict pulmonary artery diastolic pressure.

BACKGROUND

Doppler echocardiography has been used to estimate right ventricular systolic pressure noninvasively. Because right ventricular and pulmonary artery diastolic pressure are equal at the time of pulmonary valve opening, Doppler echocardiographic estimation of right ventricular pressure at this point might provide an estimate of pulmonary artery diastolic pressure.

METHODS

We studied 31 patients who underwent right heart catheterization and had tricuspid regurgitation. Pulmonary flow velocity was recorded by pulsed wave Doppler echocardiography, and tricuspid regurgitant velocity was recorded by continuous wave Doppler echocardiography. The time of pulmonary valve opening was determined as the onset of systolic flow in the pulmonary artery. Tricuspid velocity at the time of pulmonary valve opening was measured by superimposing the interval between the onset of the QRS complex on the ECG and the onset of pulmonary flow on the tricuspid regurgitant envelope. The tricuspid gradient at this instant was calculated from the measured tricuspid velocity using the Bernoulli equation. This gradient was compared to the pulmonary artery diastolic pressure obtained by right heart catheterization.

MEASUREMENTS AND RESULTS

The pressure gradient between the right atrium and right ventricle obtained at the time of pulmonary valve opening ranged from 9 to 31 mm Hg (mean, 19+/-5) and correlated closely with invasively measured pulmonary artery diastolic pressure (range, 9 to 36 mm Hg; mean, 21+/-7 mm Hg; r = 0.92; SEE, 1.9 mm Hg).

CONCLUSION

Doppler echocardiographic measurement of right ventricular pressure at the time of pulmonary valve opening is a reliable noninvasive method for estimating pulmonary diastolic pressure.

Early liver transplantation is crucial in children with liver disease and pulmonary artery hypertension

BACKGROUND/AIMS

Early liver transplantation is crucial in children with liver disease and pulmonary artery hypertension. Some severe pulmonary vascular anomalies associated with portal hypertension disappear after isolated liver transplantation. Evolution of pulmonary artery hypertension due to plexogenic arteriopathy is controversial, as this association is still considered a contraindication to isolated liver transplantation. Outcome of pulmonary hypertension after isolated liver transplantation is reported in three patients with portal hypertension.

METHODS

After echocardiographic diagnosis, the patients had a complete hemodynamic exploration, and two had a lung biopsy. After liver transplantation, the survivors had echocardiographic follow up and a second hemodynamic exploration.

RESULTS

In two children, pulmonary pressures and resistances returned to near-normal values 1 and 6 years after successful isolated liver transplantation. The third patient, with the most severe arteriopathy, had to wait 1 year for a donor, and the attempted transplantation was complicated by ventricular tachycardia; death occurred 2 days after surgery.

CONCLUSIONS

Liver transplantation can reverse pulmonary artery hypertension due to high pulmonary resistances complicating liver disease with portal hypertension, provided it is carried out at an early stage. Early detection of pulmonary hypertension by systematic echocardiography may thus be crucial in these children with portal hypertension.

Quantification of left-side intracardiac pressures and gradients using mitral and aortic regurgitant velocities by simultaneous left and right catheterization and continuous-wave Doppler echocardiography

Noninvasive determination of left-side intracardiac pressures is of clinical importance in many cardiac diseases. To test the reliability and accuracy of left-side intracardiac pressure measurements by continuous-wave Doppler echocardiography, using left-side valvular regurgitations, 47 patients with mitral regurgitation, with or without associated aortic regurgitation, underwent simultaneous Doppler and left and right catheterization. Doppler-derived left atrial and ventricular end-diastolic pressures were respectively estimated by subtracting mitral regurgitant gradient from systolic blood pressure and by diastolic blood pressure minus aortic regurgitant gradient. There were high correlations of mitral (r = 0.961) and aortic regurgitant gradients (r = 0.896) and of left atrial (r = 0.945) and ventricular end-diastolic pressures (r = 0.854) between noninvasive and invasive measurements. Also, agreement analyses showed that there was close agreement between the two technical measurements for each parameter. The present study concluded that continuous-wave Doppler echocardiography provides a reliable and accurate method for the noninvasive evaluation of left-side intracardiac pressures and gradients in patients with mitral and aortic regurgitations.

Pulmonary artery diastolic pressure: a simultaneous Doppler echocardiography and catheterization study

Pulmonary hypertension is an important determinant of the clinical presentation of and surgical approach to patients with heart disease. To confirm the utility of continuous wave Doppler echocardiography in assessing the pulmonary artery diastolic pressure in patients with pulmonary regurgitation, 51 patients representing the wide hemodynamic spectrum of pulmonary artery pressure underwent simultaneous determination of pulmonary artery diastolic pressure by continuous wave Doppler echocardiography and cardiac catheterization. Pulmonary artery diastolic pressure was estimated from the Doppler recordings by the end-diastolic pressure gradient obtained by the modified Bernoulli equation plus the estimated right atrial pressure. A correlation was observed (r = 0.935, SEE = 7.4 mmHg) between Doppler and catheterization pulmonary artery diastolic pressure. In addition, comparison between the mean diastolic pressure gradient across the pulmonary valve by Doppler and pulmonary artery diastolic pressure at catheterization yielded a high correlation (r = 0.947, SEE = 5.1 mmHg). These data demonstrate that continuous wave Doppler echocardiography is a useful noninvasive technique for evaluating the pulmonary artery diastolic pressure in patients with pulmonary regurgitation.

Doppler echocardiographic assessment of changes in pulmonary artery pressure associated with vasodilating therapy in patients with congestive heart failure

Transpulmonic pressure gradient and pulmonary artery pressures can be estimated from the Doppler pulmonary regurgitant flow velocities by applying the simplified Bernoulli equation. In this study, continuous-wave Doppler echocardiography was used to assess changes in pulmonary regurgitant flow velocities associated with administration of vasodilators in 10 patients with congestive heart failure. M-Mode echocardiographic parameters such as left ventricular end-systolic and end-diastolic dimension and fractional shortening did not change with administration of vasodilators. Pulmonary regurgitant flow velocity at end diastole decreased from 1.9 +/- 0.6 to 1.3 +/- 0.3 m/sec (p less than 0.01), and Doppler-estimated transpulmonic pressure gradient at end diastole decreased from 16 +/- 11 to 8 +/- 4 mm Hg (p less than 0.01). Doppler-estimated transpulmonic pressure gradient at end diastole was compared with catheterization-determined pulmonary arterial end-diastolic pressure before and after administration of vasodilators in three patients, and there was a good agreement between these measurements. Thus noninvasive and sensitive assessment of the effect of vasodilators on pulmonary arterial end-diastolic pressure in patients with congestive heart failure is possible with continuous-wave Doppler echocardiographic measurement of pulmonary regurgitant flow velocities.