Pressures

Tissue Doppler imaging in patients with moderate to severe aortic valve stenosis: clinical usefulness and diagnostic accuracy

BACKGROUND

Mitral annular velocities derived from tissue Doppler imaging (TDI) provide information about left ventricular (LV) long-axis function and allow for the assessment of LV filling pressures in selected subsets of patients. It was the aim of this study to assess the usefulness of TDI in patients with moderate to severe aortic valve stenosis (AS).

METHODS

Twenty-three patients with moderate to severe AS (mean aortic valve area 0.8 +/- 0.4 cm2), in whom coronary artery disease had been ruled out, and 36 asymptomatic age-matched control subjects underwent assessment of ejection fraction, fractional shortening, and mitral inflow (E, A, E/A ratio). TDI velocities (S', E', A') were derived from the septal mitral annulus. In patients with AS, LV pressure before atrial contraction (LV pre-A pressure), LV end-diastolic pressure, and cardiac index were measured during cardiac catheterization.

RESULTS

In patients with AS, systolic (S') and early diastolic mitral annular velocities (E') were significantly reduced in comparison to control subjects (systolic, 5.5 +/- 1.2 vs 8.3 +/- 1.3 cm/s; early diastolic, 5.6 +/- 1.6 vs 10.2 +/- 3.0 cm/s, P <.001 for both comparisons), but ejection fraction, fractional shortening, and cardiac index were normal. In patients with AS, LV pre-A pressures (14 +/- 4 mm Hg) and end-diastolic pressures were high (19 +/- 7 mm Hg). In such patients, the mitral E/E' ratio was significantly related to LV pre-A pressure (r = 0.75, P <.001) and to LV end-diastolic pressure (r = 0.78, P <.001). In patients with AS, an E/E' ratio > or =13 identified an LV end-diastolic pressure >15 mm Hg, with a sensitivity of 93% and a specificity of 88%.

CONCLUSIONS

In patients with moderate to severe AS, TDI allows for a reliable, noninvasive estimation of filling pressures. In such patients, systolic long-axis function is impaired even in the presence of normal ejection fraction and cardiac index. Thus, TDI integrates information about systolic and diastolic performance and may be a useful addition in the echocardiographic workup and care of patients with AS.

An open-label, prospective, observational study of the incidence of coronary artery disease in patients with hiv infection receiving highly active antiretroviral therapy

BACKGROUND

The association of highly active antiretroviral therapy (HAART) regimens that include protease inhibitors (PIs) with metabolic and somatic disorders has raised concerns about the possibility of an increased risk of coronary artery disease (CAD) in patients with HIV infection.

OBJECTIVE

The aim of this study was to assess the incidence of CAD in previously untreated HIV infected outpatients who received reverse transcriptase inhibitors with or without PIs.

METHODS

In this open-label, multicenter, prospective, observational trial, previously untreated and asymptomatic HIV-infected Italian patients were followed to assess the incidence of CAD (primary end point) according to the HAART regimen they received: 2 nucleoside analogue reverse transcriptase inhibitors (NRTIs) in combination with PIs (group PI+) or 1 non-nucleoside reverse transcriptase inhibitor in combination with 2 NRTIs (group PI-). Patients underwent clinical examination and laboratory testing every 4 months.

RESULTS

A total of 1551 HIV-infected patients (994 [64%] men; median age, 35 years; range, 22-50 years) were followed for a median 36 months (range, 34-42 months). The cumulative annual incidence of CAD-related events was 9.8/1000 in group PI+ and 0.8/1000 in group PI- (P < 0.001). The annual incidence of myocardial infarction was 5.1/1000 in group PI+ and 0.4/1000 in group PI- (P < 0.001). Independent of patient age, the incidence of CAD was greater among men (P < 0.001) and patients who smoked >20 cigarettes per day (P < 0.001). Lipodystrophy and metabolic alterations were observed in 62% of patients in group PI+ and in 4% of patients in group PI- (P < 0.001). Of 23 patients receiving PIs who developed CAD, 17 (73.9%) had lipodystrophy and all 23 had hypertriglyceridemia and hypercholesterolemia.

CONCLUSIONS

According to our findings, HAART that includes PIs may accelerate the onset of CAD-related events in young, male, heavy smokers who develop metabolic disorders and lipodystrophy during therapy. Patients with increased coronary risk should receive careful cardiac monitoring if treated with PIs.

Doppler echocardiographic evaluation of left ventricular end-diastolic pressure in patients with coronary artery disease

Pulmonary venous flow velocity recordings have been found to be useful in complementing the information obtained from the mitral flow velocity and improving the assessment of left ventricular diastolic pressures. This study was undertaken to evaluate the accuracy of mitral flow and pulmonary venous flow variables, recorded by transthoracic Doppler echocardiography, in estimating left ventricular end-diastolic pressure (LVEDP) in 101 consecutive patients with coronary artery disease undergoing diagnostic left-sided heart catheterization. Patients were assigned to three groups according to the values of LVEDP (group 1, < or = 12 mm Hg; group 2, between 13 and 19 mm Hg; and group 3, > or = 20 mm Hg). LVEDP correlated most strongly with systolic fraction of pulmonary venous flow (r = -0.76), isovolumic relaxation time (r = -0.76), E/A ratio (r = 0.74), deceleration time of early mitral flow (r = -0.74), and mitral A wave duration/pulmonary venous A wave duration (AD/PVAD) ratio (r = -0.70) (p < 0.01 for each correlation). Discriminant analysis demonstrated that deceleration time, AD/PVAD ratio, and isovolumic relaxation time were major determinants of LVEDP, with 87.1% of patients correctly assigned to study groups; 97% of patients of group 1 and 95% of patients of group 3 were identified, whereas the accuracy in identifying the patients of group 2 was lower (41%). Deceleration times of 140 msec or less and AD/PVAD ratios of 0.9 or less were the best cutoff points in predicting an LVEDP of 20 mm Hg or greater. Multiple linear regression analysis demonstrated that the combination of mitral flow and pulmonary venous flow velocity variables provided a better estimation of LVEDP compared with that obtained from mitral flow velocity recordings alone (r = 0.88 versus 0.79; F test, 20.6). We conclude that combined analysis of mitral flow and pulmonary venous flow velocity provides, in patients with coronary artery disease, a noninvasive estimation of LVEDP with an accurate prediction of pressures of 12 mm Hg or less and 20 mm Hg or greater and less accurate prediction of intermediate values.

Pulmonary venous flow velocities recorded by transthoracic Doppler ultrasound: relation to left ventricular diastolic pressures

OBJECTIVES

This study was conducted to investigate whether pulmonary venous flow variables measured by transthoracic Doppler ultrasound can help identify patients with elevated left ventricular end-diastolic or filling pressures, or both.

BACKGROUND

A widened left atrial pressure A wave occurs when left ventricular end-diastolic pressure is increased. Increased duration of pulmonary venous flow reversal at atrial systole might therefore be a marker for elevated end-diastolic pressure. Decreased systolic pulmonary venous flow is shown to be related to increased left ventricular filling pressure in studies using transesophageal Doppler echocardiography.

METHODS

Left ventricular pressures at late diastole were measured by fluid-filled catheters in 50 consecutive patients undergoing diagnostic cardiac catheterization. Pulmonary venous and mitral flow velocities were recorded by transthoracic pulsed Doppler ultrasound.

RESULTS

Adequate recordings were obtained in 45 patients. Pulmonary venous flow reversal exceeding the duration of the mitral A wave predicted left ventricular end-diastolic pressure > 15 mm Hg with a sensitivity of 0.85 and a specificity of 0.79. This difference in flow duration correlated well with the increase in ventricular pressure (r = 0.70, p < 0.001) at atrial systole and the end-diastolic pressure (r = 0.68, p < 0.001). The systolic fraction of pulmonary venous flow was markedly decreased (< 0.4) in all patients with a pre-A pressure (left ventricular pressure before atrial systole) > 18 mm Hg.

CONCLUSIONS

Pulmonary venous flow reversal exceeding the duration of the mitral A wave indicates an exaggerated increase in left ventricular late diastolic pressure. Pulmonary venous systolic fraction < 0.4 suggests markedly increased ventricular filling pressure.

Dynamic cardiomyoplasty in chronic left ventricular failure: an experimental model

Dynamic cardiomyoplasty continues to attract interest as a therapeutic option in the management of heart failure. In a large animal model of ischemic heart failure, we have compared dynamic cardiomyoplasty with both adynamic cardiomyoplasty and a control group. Heart failure was induced by coronary artery ligation in sheep, and under the same anesthetic dynamic cardiomyoplasty (n = 5), adynamic cardiomyoplasty (n = 4), or no further procedure was performed (n = 5). After recovery the animals were housed for a further 3 months. The dynamic cardiomyoplasty underwent a recognized muscle transformation protocol during this period. At terminal studies, the animals were hemodynamically assessed, both under baseline conditions and after colloid volume loading. The data at baseline were compared with unpaired t tests, and the function curves created by volume loading were compared by analysis of variance. Although the changes at baseline were small, there were highly significant improvements in the function curves in the dynamic cardiomyoplasty group when the stimulators were turned on compared with stimulators off (p = 0.005) for cardiac output; p = 0.035 for left ventricular end-diastolic pressure; p = 0.002 for pulmonary artery capillary wedge pressure; p = 0.004 for stroke volume; and p = 0.003 for cardiac power). There were also significant improvements in indices of cardiac performance when the dynamic cardiomyoplasty group was compared with both the control and adynamic cardiomyoplasty groups. We conclude that there is experimental evidence that cardiomyoplasty augments cardiac function in a model of chronic left ventricular failure.

Half time of the diastolic aortoventricular pressure difference by continuous wave Doppler ultrasound: a measure of the severity of aortic regurgitation?

Thirty four patients with aortic regurgitation were studied by continuous wave Doppler ultrasound. In 30 of these the regurgitation was graded by cineangiography as mild, moderate, or severe and in four severe regurgitation was confirmed at operation. The half times of the aortoventricular pressure differences obtained with Doppler compared well with those obtained from pressure recordings at catheterisation. The relation between pressure half times and cineangiographic gradings of severity was not consistent. Similarly, a control group of patients without aortic regurgitation showed a wide range of the invasively recorded pressure half times which overlapped with those in patients with aortic regurgitation. This suggests that factors such as systemic vascular resistance, and aortic and left ventricular compliance can have an appreciable effect on the pressure half time. If these factors are not included the method will be of limited value, except in patients with pressure half times of less than 300 ms, when regurgitation invariably is severe. These results suggest that at present the method is of value only in recognising the patients with the most severe aortic regurgitation who need early operation.