Doppler-derived rate of left ventricular pressure rise. Its correlation with the postoperative left ventricular function in mitral regurgitation

Preoperative Echocardiographically Derived Mean dP/dTic Predicts Early Post-operative Dysfunction in Children Undergoing Mitral Valve Surgery

Mean dP/dtic is a quantitative measurement of ventricular function that can be obtained noninvasively by echocardiography. In adults with mitral regurgitation (MR), it has been shown to be a more sensitive predictor of postoperative left ventricular ejection fraction (EF). The utility of dP/dtic in pediatric congenital heart diseases with MR has been underexplored. Patients (0 to ≤ 19 years) with MR who underwent mitral valve (MV) repair or replacement from 2015 to 2021 were included. Echocardiographically derived mean dP/dtic, Tei index, and EF were used to assess and compare ventricular function prior to, shortly after, and late after MV surgery. Study cohort included 61 patients (age 4.5 [IQR 0.14, 18.7] years, 89% MV repair, 11% MV replacement). Median time intervals between surgery and preoperative, early postoperative, and late postoperative echocardiograms were 6 days, 6 days, and 350 days, respectively. Median EF was 62% (z-score - 0.40) preoperatively, 56% (z-score - 1.40) early postoperatively, and 61% (z-score - 0.60) late postoperatively. Median dP/dtic was 1393 (IQR 1029, 1775) mmHg/s preoperatively, 1178 (IQR 886, 1946) mmHg/s early postoperatively, and 1270 (IQR 791, 1765) mmHg/s late postoperatively. Preoperative median dP/dtic correlated with early and late postoperative EF. Preoperative EF was not significantly correlated with early postoperative EF, but was correlated with late postoperative EF. Mitral valve intervention in pediatric patients is associated with an initial decline but subsequent recovery of systolic function. Non-invasively derived mean dP/dtic may offer advantages over other preoperative echocardiographic indices to predict postoperative systolic function.

Functional Mitral Regurgitation in Heart Failure

Functional mitral regurgitation (FMR) in the setting of left ventricular (LV) dysfunction and heart failure portends a poor prognosis. Guideline-directed medical therapy remains the cornerstone of initial treatment, with emphasis placed on treatment of the underlying LV dysfunction, as FMR is a secondary phenomenon and a disease due to LV remodeling. Surgical correction of FMR is controversial because it typically does not address the underlying mechanism and etiology of the condition. However, new, minimally invasive transcatheter therapies, in particular the MitraClip system, have shown promise in the treatment of FMR in selected patients. This review will summarize the pathophysiology underlying FMR, the prognosis of patients with heart failure and FMR, and the various medical and procedural treatment options currently available and under investigation.

Rate of left ventricular pressure change by Doppler echocardiography in dogs with chronic mitral valve disease at different stages of congestive heart failure

Although the major pathological feature of chronic mitral valve disease is mitral regurgitation, myocardial dysfunction has been suggested to be present in dogs with chronic mitral valve disease. However, accurate assessment of myocardial function remains challenging. Doppler-derived rate of left ventricular pressure change is a simple, less load-dependent method for evaluating myocardial function. We aimed to evaluate Doppler-derived rate of left ventricular pressure change for assessing myocardial function in different stages of dogs with chronic mitral valve disease. This analytical cross-sectional study recruited 55 client-owned dogs with chronic mitral valve disease prospectively. Based on physical examination, indirectly measured blood pressure, routine hematologic and biochemistry examinations, thoracic radiography, electrocardiography, and echocardiography, dogs were diagnosed as mitral valve disease and excluded for systemic diseases and other cardiac diseases. They were classified according to the International Small Animal Cardiac Health Council scales. Doppler-derived rates of left ventricular pressure rise and fall (dP/dt and -dP/dt) were analyzed by two investigators using continuous-wave Doppler imaging. Doppler-derived dP/dt was higher in dogs of class III_a than in those of the other classes, whereas values of -dP/dt decreased significantly with the severity of congestive heart failure. The peak velocity of the early diastolic wave and -dP/dt were identified as independent predictors of congestive heart failure. Our findings suggested that Doppler-derived dP/dt and -dP/dt, used in combination with conventional echocardiographic variables, could allow a better understanding of myocardial dysfunction and a possibility for prediction of the risk of heart failure in dogs with chronic mitral valve disease.

A novel noninvasive method to assess left ventricular -dP/dt using diastolic blood pressure and isovolumic relaxation time

BACKGROUND

Left ventricular Doppler-derived -dP/dt determined from the continuous-wave Doppler spectrum of the mitral regurgitation (MR) jet has been shown to be a valuable marker of diastolic function, but requires the presence of MR for its assessment. We sought to determine if a novel method of determining -dP/dt using the diastolic blood pressure and isovolumic relaxation time (DBP-IVRT method) correlates with Doppler-derived -dP/dt using the MR method (Doppler-MR method).

METHODS

Thirty-three patients with less than severe MR were enrolled. -dP/dt was determined using the Doppler-MR method from the continuous-wave Doppler spectrum of the MR jet (32 mmHg/time from 3 to 1 m/sec). -dP/dt was also determined using the DBP-IVRT method using the following equation: -dP/dt = (DBP - LVEDP)/IVRT, where left ventricular end-diastolic pressure (LVEDP) was estimated based on tissue Doppler and mitral inflow patterns.

RESULTS

Twenty-five patients had adequate Doppler waveforms for analysis. The average amount of MR was mild-to-moderate severity. The mean -dP/dt was 680 ± 201 mmHg by the Doppler-MR method and 681 ± 237 mmHg by the DBP-IVRT method. There was a significant correlation between the 2 methods of determining -dP/dt (Pearson r = 0.574, P = 0.003). The Bland-Altman plot revealed almost no bias between the 2 methods; the difference in -dP/dt between the 2 techniques was noted to be greater for patients with higher -dP/dt, however.

CONCLUSION

Diastolic blood pressure and isovolumic relaxation time may be used to noninvasively assess diastolic function in patients who do not have MR, especially in those with reduced diastolic function.

Non-geometric echocardiographic indices of ventricular function in patients with a Fontan circulation

BACKGROUND

Complex anatomy and limited windows complicate echocardiographic assessments of ventricular function in Fontan patients. For the Pediatric Heart Network Fontan Cross-Sectional Study, data were acquired from which mean ventricular pressure change during isovolumetric contraction (dP/dt(ic)), Tei index, and maximal systolic annular velocity (S') could be measured. The purpose of this study was to compare these nongeometric indices of ventricular function to cardiac magnetic resonance (CMR) measurements of ventricular ejection fraction (EF).

METHODS

Echocardiographic and CMR studies were performed prospectively using standardized protocols; measurements were completed by core laboratories. Data from both modalities were available from 137 patients.

RESULTS

A weak but statistically significant correlation was observed between mean dP/dt(ic) and CMR-derived EF (r = 0.20, P = .022). This correlation was strengthened when preload was taken into account (r = 0.30, P = .001). Statistically significant correlations did not exist between CMR-derived EF and the Tei index or S'.

CONCLUSIONS

Among Fontan patients, the correlation between CMR-derived EF and nongeometric echocardiographic indices of ventricular function is not strong. Of the indices evaluated, however, mean dP/dt(ic) appears to be the best.

Relationship between intracardiac impedance and left ventricular contractility in patients undergoing cardiac resynchronization therapy

AIMS

Cardiac resynchronization therapy (CRT) has dramatically improved the symptoms and prognosis of patients with heart failure in large randomized clinical trials. Optimization of device settings may maximize benefit on an individual basis, although the best method for this is not yet established. We evaluated the use of cardiogenic impedance measurements (derived from intracardiac impedance signals) in CRT device optimization, using invasive left ventricular (LV) dP/dtmax as the reference.

METHODS AND RESULTS

Seventeen patients underwent invasive haemodynamic assessment using a pressure wire placed in the LV cavity at the time of CRT device implantation. Intracardiac impedance measurements were made at different atrioventricular (AV) and interventricular (VV) delays and compared with LV dP/dtmax. We assessed the performance of patient-specific and generic impedance-based models in predicting acute haemodynamic response to CRT. In two patients, LV catheterization with the pressure wire was unsuccessful and in two patients LV lead delivery was unsuccessful; therefore, data were acquired for 13 out of 17 patients. Left ventricular dP/dtmax was 919±182 mmHg/s at baseline and this increased acutely (by 24%) to 1121±226 mmHg/s as a result of CRT. The patient-specific impedance-based model correctly predicted the optimal haemodynamic response (to within 5% points) for AV and VV delays in 90 and 92% of patients, respectively.

CONCLUSION

Cardiogenic impedance measurements are capable of correctly identifying the maximum achievable LV dP/dtmax as measured by invasive haemodynamic assessment. This study suggests that cardiogenic impedance can potentially be used for CRT optimization and may have a role in ambulatory assessment of haemodynamics.

Assessment of myocardial deformation: Predicting medium-term left ventricular dysfunction after surgery in patients with chronic mitral regurgitation

INTRODUCTION AND OBJECTIVES

The development of left ventricular dysfunction after mitral valve replacement is a common problem in patients with chronic severe mitral regurgitation. Assessment of myocardial deformation enables myocardial contractility to be accurately estimated. Our aim was to compare the value of the preoperative strain and strain rate derived by either speckle-tracking echocardiography or tissue Doppler imaging (TDI) for predicting the medium-term decrease in left ventricular ejection fraction (LVEF) following surgery.

METHODS

This prospective study involved 38 consecutive patients with chronic severe mitral regurgitation who were scheduled for mitral valve replacement. The longitudinal strain and strain rate in the interventricular septum were measured preoperatively using speckle-tracking echocardiography and TDI. The LVEF was determined preoperatively and postoperatively using 3-dimensional echocardiography. Echocardiographic assessments were performed in the 48 hours prior to surgery and 6 months postoperatively.

RESULTS

The patients' mean age was 59.9+/-11.3 years and 10 (29.4%) were male. Both speckle-tracking echocardiography and TDI were found to be predictors of a >10% decrease in LVEF at 6 months. However, the predictive value of speckle-tracking echocardiography was greater than that of TDI. The longitudinal strain at baseline in the interventricular septum as measured by speckle-tracking echocardiography was the most powerful predictor; the area under the curve was 0.85 and the optimal cut-off value was -0.11.

CONCLUSIONS

Speckle-tracking echocardiography can be used to predict a decrease in LVEF over the medium term after mitral valve replacement. Moreover, the predictive accuracy of speckle-tracking echocardiography was greater than that of TDI.

Can we improve outcomes in patients with previous coronary artery bypass surgery admitted for acute coronary syndrome?

INTRODUCTION AND OBJECTIVES

Prognosis and in-hospital management of patients with acute coronary syndrome (ACS) and a history of coronary artery bypass graft (CABG) surgery are still debated. The objective of this study was to characterize ACS patients with a CABG and to compare their in-hospital and postdischarge outcomes with those of patients without a CABG.

METHODS

This ongoing prospective observational study included 1,495 consecutive patients admitted for ACS to a coronary care unit and followed up for a mean of 19 months. There were two groups: group A (n=73), with CABGs; and group B (n=1,223), without CABGs.

RESULTS

Group A patients were more often male (86.3% versus 69.1%; P=.002), and more frequently had a history of diabetes, myocardial infarction and heart failure. Group B patients more frequently had ST-elevation myocardial infarction, and had a higher median ejection fraction (53% [interquartile range, 47%-60%] vs. 50% [42%-55%]; P< .01) and peak troponin-I concentration. There was no difference in the use of invasive techniques. Regarding medication, Group B patients were more likely to receive dual antiplatelet therapy at discharge. No significant difference was observed in in-hospital mortality (9.5% versus 5.9%; P=.2) or mortality at 1 month, 6 months or 1 year (9.8% versus 9.1%; log-rank test, P=.87) and the cumulative major adverse cardiac event rate was equally low in both groups. The presence of a CABG was associated with more readmissions for unstable angina (11.3% vs. 3.1%; P< .01).

CONCLUSIONS

In our ACS patients, the presence of a CABG had no significant influence on short- or medium-term outcomes, such as all-cause mortality and adverse cardiac events.

Detection of left ventricular dysfunction with Tei index in normal ejection fraction patients with mitral regurgitation before mitral valve surgery

Ejection fraction (EF) was not considered a reliable parameter of left ventricular (LV) function and was normal in most patients with chronic mitral regurgitation (MR), whereas LV dysfunction expressed as decreased EF was often shown after mitral valve surgery. This study sought the ability of the Tei index to detect latent LV dysfunction in patients with MR and apparently normal EF. One hundred eight patients with apparently normal EF (EF > or =50%) and chronic severe MR who underwent mitral valve repair were investigated. EF was significantly decreased after surgery and LV dysfunction (EF <50%) was shown in 37 patients (34% of all patients). The preoperative Tei index significantly correlated with postoperative EF in all patients (r = -0.64, p <0.0001) and asymptomatic patients (n = 44; r = -0.57, p <0.0001). By setting the preoperative Tei index >0.5 to predict postoperative EF <50%, this index had sensitivity, specificity, and accuracy of 89%, 85%, and 86% in all patients and 80%, 85%, and 84% in asymptomatic patients, respectively. In conclusion, a preoperative Tei index >0.5 allowed prediction of postoperative LV dysfunction in patients with MR with apparently normal EF. Thus, earlier surgery is recommended in asymptomatic patients with MR with normal EF, but Tei index >0.5.

Evaluation of left ventricular short- and long-axis function in severe mitral regurgitation using 2-dimensional strain echocardiography

BACKGROUND

Few data exist on the changes in left ventricular (LV) short- and long-axis function and their usefulness as markers of LV contractile function in patients with chronic, severe mitral regurgitation (MR).

METHODS

We studied 59 patients who had severe MR with an ejection fraction > or =50% and 34 healthy controls. Speckle tracking imaging was performed to measure peak systolic radial (SR(R)), circumferential (SR(C)), and longitudinal strain rates (SR(L)). In all patients, the peak rate of LV pressure rise (peak dP/dt) was measured using a micromanometer-tipped catheter. The patients were subdivided into patients with preserved (group 1, peak dP/dt > or =1,300 mm Hg/s [n = 30]) and depressed (group 2 [n = 29]) contractile function.

RESULTS

SR(L) was significantly depressed in groups 1 and 2 when compared with the control group, but there was no difference between groups 1 and 2. In contrast, SR(R) and SR(C) were depressed only in group 2, whereas there were no differences between the control group and group 1. SR(R) and SR(C) correlated well with peak dP/dt (r = 0.71, P <.001 and r = -0.63, P <.001, respectively), whereas SR(L) did not. These findings suggest that LV long-axis function becomes depressed earlier than short-axis function in the chronic remodeling process.

CONCLUSIONS

Left ventricular short-axis function is a useful marker of LV contractility in patients with chronic, severe MR. Left ventricular long-axis function becomes depressed earlier in the chronic remodeling process. Therefore, evaluation of short-axis as well as long-axis function might be important for better assessment of LV contractile function in these patients.

Evaluation of Left Ventricular Contractile Function Using Noninvasively Determined Single-beat End-systolic Elastance in Mitral Regurgitation: Experimental Validation and Clinical Application

OBJECTIVE

We performed this study to validate the single-beat estimation of end-systolic elastance (E(es)) in an animal model of chronic mitral regurgitation (MR) and to use E(es) to predict postoperative left ventricular (LV) systolic function with the noninvasively derived single-beat E(es) (E(es-s)) in patients with MR.

METHODS

Eight sheep with MR were studied under 4 different loading conditions. E(es) was measured as the slope of the end-systolic pressure-volume relationship with a conductance catheter during inferior vena cava occlusion. E(es-s) was calculated using a bilinearly approximated time-varying elastance curve. We also studied 105 patients with MR who had undergone mitral valve repair. All measurements in these patients were performed before surgery and repeated at about 1 week after surgery.

RESULTS

In the animals in a total of 23 different stages, E(es-s) showed a good correlation and agreement with invasively determined E(es) (y = 0.84 x + 0.38; r = 0.8; P < .01, mean difference = 0.1 +/- 0.6 mm Hg/mL). In the clinical study, preoperative E(es-s) (r = 0.77; P < .001) and end-systolic volume index correlated well with postoperative ejection fraction (r = -0.69; P < .001). Multivariate analyses revealed that only E(es-s) was an independent predictor of postoperative LV function. Preoperative E(es-s) less than or equal to 1.0 mm Hg/mL was most predictive for identifying patients with LV dysfunction after surgery (sensitivity 87%; specificity 76%).

CONCLUSIONS

LV end-systolic elastance can be estimated noninvasively and is useful to detect latent LV dysfunction in patients with MR before surgery.

Quantitative left ventricular systolic function: From chamber to myocardium

One of the most common indications for obtaining a Doppler echocardiographic study is to ascertain left ventricular (LV) systolic function. There are many ways in which LV function can be determined, but an important assumption that is often overlooked is that every measure that we commonly use is only a surrogate marker of LV function due to the fact that it is impossible to characterize the complex geometric and volumetric function of the ventricle (or myocyte) in a single number. Stated in another way, there is no one perfect measure of LV function. The ejection fraction has emerged as the preeminent method to express LV performance, but although ejection fraction is universally accepted, there are a number of other techniques that can assess LV function and, when taken together, provide a more comprehensive picture both of global and regional LV function. Each of these measures (including ejection fraction) has variable dependence on loading conditions, heart rate, and geometric position that limits its accuracy. Understanding the limitations of each measure will allow the physician to more intelligently understand the true status of the myocardium.

Functional and prognostic implications of left ventricular contractile reserve in patients with asymptomatic severe mitral regurgitation

OBJECTIVE

To evaluate contractile reserve (CR) determined by exercise echocardiography in predicting clinical outcome and left ventricular (LV) function in asymptomatic severe mitral regurgitation (MR).

DESIGN

Cohort study.

SETTING

Regional cardiac centre.

PATIENTS AND OUTCOME MEASURES

LV volumes and ejection fraction (EF) were measured at rest and after stress in 71 patients with isolated MR. During follow up (mean (SD) 3 (1) years), EF and functional capacity were serially assessed and cardiac events (cardiac death, heart failure, and new atrial fibrillation) were documented.

RESULTS

CR was present in 45 patients (CR+) and absent in 26 patients (CR-). Age, resting LV dimensions, EF, and MR severity were similar in both groups. Mitral surgery was performed in 19 of 45 (42%) CR+ patients and 22 of 26 (85%) CR- patients. In patients undergoing surgery, CR was an independent predictor of follow up EF (p = 0.006) and postoperative LV dysfunction (EF < 50%) persisted in five patients, all in the CR- group. Event-free survival was lower in surgically treated patients without CR (p = 0.03). In medically treated patients, follow up EF was preserved in those with intact CR but progressively deteriorated in patients without CR, in whom functional capacity also deteriorated.

CONCLUSIONS

Evaluation of CR by exercise echocardiography may be useful for risk stratification and may help to optimise the timing of surgery in asymptomatic severe MR.

Pulsed tissue Doppler imaging detects early myocardial dysfunction in asymptomatic patients with severe mitral regurgitation

OBJECTIVE

To assess whether tissue Doppler myocardial imaging (TDI) indices can predict postoperative left ventricular function in patients with mitral regurgitation (MR) after surgical correction.

METHODS

84 patients (mean (SD) age 54.3 (10.8) years) with asymptomatic severe MR, an end systolic diameter < 45 mm, and an ejection fraction (EF) > 60% were subdivided in two groups: 43 patients with a postoperative EF reduction < 10% (group 1) and 41 patients with a postoperative EF reduction > or = 10% (group 2).TDI systolic indices of the lateral annulus were analysed preoperatively to assess myocardial systolic wave (Sm) velocity, myocardial precontraction time (PCTm), myocardial contraction time (CTm), and the PCTm:CTm ratio.

RESULTS

Postoperative EF decreased significantly (from 67 (5)% to 60 (5.5)%, p = 0.0001). Group 2 had a higher PCTm, CTm, and PCTm:CTm ratio and a lower Sm velocity than group 1 (PCTm 100.4 (19) ms v 82 (21.8) ms, p = 0.004; CTm 222 (3.1) ms v 215 (2.3) ms, p = 0.01; PCTm:CTm 0.45 (0.08) v 0.38 (0.09), p = 0.001; Sm velocity 10.4 (1.1) cm/s v 13 (1.3) cm/s, p = 0.0001). Multivariate regression analysis showed that the combination of PCTm:CTm ratio > or = 40 ms and Sm velocity < or = 10.5 cm/s was the main independent predictor of postoperative EF reduction > or = 10% (sensitivity 78%, specificity 95%).

CONCLUSIONS

TDI systolic indices can predict postoperative left ventricular function in patients with asymptomatic MR undergoing surgical correction.

Relationship of ventricular longitudinal function to contractile reserve in patients with mitral regurgitation

BACKGROUND

Latent left ventricular (LV) dysfunction in patients with valvular or myocardial disease may be identified by loss of contractile reserve (CR) at exercise echocardiography. Contraction in the LV longitudinal axis may be more sensitive than radial contraction to minor disturbances of LV function. We sought to determine whether tissue Doppler measurement of longitudinal function could be used to identify CR.

METHODS

Exercise echocardiography was performed in 86 patients (20 women, age 53 +/- 18 years), 72 with asymptomatic or minimally symptomatic mitral regurgitation, and 14 normal controls. Pulsed-wave tissue Doppler imaging (DTI) was used to measure maximum annular systolic velocity at rest and stress. Inducible ischemia was excluded by analysis of wall motion by an experienced observer. CR was defined by >or=5% improvement of stress compared with rest ejection fraction (EF). Exercise capacity was assessed from expired gas analysis.

RESULTS

CR was present in 34 patients with mitral regurgitation (47%); peak EF in patients with and without CR was 74% +/- 11% versus 54% +/- 15% (P <.0001). CR could not be predicted by resting EF, volumes or sphericity, and DTI measurement of base-apex function was the only resting echocardiographic parameter to distinguish between patients with and without CR (10 +/- 2 vs 8 +/- 2 cm/s, P <.03). This parameter showed greater differences after stress (14 +/- 4 vs 11 +/- 3 cm/s, P <.001). Patients with CR showed lower peak DTI than controls, as well as lower exercise capacity and EF response to exercise. In a multiple linear regression model, rest DTI (P =.03) was an independent correlate of contractile reserve. The other correlates were age (P <.0001), resting (P <.0001) and peak end-systolic volume (P =.01), and resting (P <.0001) and peak end-diastolic volume (P <.0001); the model r(2) was 0.93 (P <.001).

CONCLUSION

In the absence of regional LV dysfunction, measurement of longitudinal axis function by DTI may be a marker of CR.

Use of tissue Doppler echocardiography in early detection of left ventricular systolic dysfunction in patients with mitral regurgitation

OBJECTIVE

Left ventricular ejection fraction (EF) and left ventricular (LV) end-systolic diameter measurements are the most widely accepted and utilized methods to demonstrate LV dysfunction in patients with mitral regurgitation (MR). However, these parameters still have many drawbacks in predicting early LV dysfunction. This study investigates the clinical usefulness of tissue Doppler echocardiography technique in detecting early disturbance of myocardial contractility in asymptomatic patients with chronic, severe MR and normal LV ejection fraction values.

METHODS AND RESULTS

Regional systolic peak velocities of mitral annular motion during the ejection phase of systole (SW2) were obtained at the mitral annuli of the ventricular septal, lateral, anteroseptal, posterior, anterior and inferior wall sites in the long axis in 31 asymptomatic patients with severe MR (with a regurgitant volume of more than 50 ml) and with EFs more than 60%. The patients were grouped according to their dP/dt values (more or less than 1300 mmHg/s) estimated non-invasively by using continuous Doppler wave of MR SW2 measurements of Group I were higher than Group II in all of the analyzed segments. The difference was statistically significant for all of the segments. SW2 values of the whole study group was moderately correlated with dP/dt measurements in all of the analyzed segments other than the interventricular septum.

CONCLUSION

SW2 measurements in the long axis, which are considered to be relatively independent from afterload conditions may be helpful in early detection (while EF is still in normal range) of LV systolic dysfunction during the follow-up of patients with chronic MR.

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. Activated partial thromboplastin time Haemoglobin Packed cell volume Prothrombin time Red cell count

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

OBJECTIVE

To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation.

PROCEDURE

Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs.

RESULTS

Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocardiography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001).

CONCLUSION

It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.

Noninvasive assessment of left ventricular isovolumic contraction and relaxation with continuous wave Doppler aortic regurgitant velocity signals: an in vivo validation study

The purpose of this study was to provide fundamental in vivo validation of a method with the use of aortic regurgitant (AR) jet signals recorded with continuous wave (CW) Doppler for assessing left ventricular (LV) isovolumic contraction and relaxation. Preliminary studies have suggested that analysis of CW Doppler AR velocity signals permits the estimation of LV positive and negative dP/dt. We studied 19 hemodynamically different states in 6 sheep with surgically induced chronic aortic regurgitation. CW AR velocity spectra and high-fidelity LV and aortic pressures were recorded simultaneously. Rates of LV pressure rise and fall (RPR and RPF) were calculated by determining the time interval between points at 1 m/s and 2.5 m/s in the deceleration and acceleration slopes of the CW Doppler AR velocity envelope (corresponding to a pressure change of 21 mm Hg). RPR and RPF calculated by CW Doppler analysis for each state were compared with the peak positive dP/dt and negative dP/dt, obtained from the corresponding high-fidelity LV pressure curve, respectively. The LV peak positive and negative dP/dt derived by catheter ranged from 817 to 2625 mm Hg/s and from 917 to 2583 mm Hg/s, respectively. Multiple regression analysis showed that Doppler RPR correlated well with catheter peak positive dP/dt (r = 0.93; mean differences, -413 +/- 250 mm Hg/s). There was also good correlation and agreement between Doppler RPF and the catheter peak negative dP/dt (r = 0.89; mean difference, -279 +/- 239 mm Hg/s). Both Doppler-determined RPR and RPF underestimated their respective LV peak dP/dt. CW Doppler AR spectra can provide a reliable noninvasive estimate of LV dP/dt and could be helpful in the serial assessment of ventricular function in patients with aortic regurgitation.

Doppler-derived dP/dt and -dP/dt predict survival in congestive heart failure

OBJECTIVES

The purpose of this study was to evaluate the ability of novel Doppler indices of left ventricular (LV) systolic and diastolic function to predict survival in patients with congestive heart failure (CHF).

BACKGROUND

Congestive heart failure is associated with an increased risk of death or cardiac transplantation, yet techniques to predict survival are limited.

METHODS

Doppler-derived dP/dt and - dP/dt were determined prospectively from the continuous-wave Doppler spectrum of the mitral regurgitation jet (dP/dt = 32/time between 1 and 3 m/s; -dP/dt = 32/time between 3 and 1 m/s) in 56 patients with chronic CHF (age, 60 +/- 15 years; LV ejection fraction, 23 +/- 9%). Baseline clinical and echocardiographic variables were also obtained, and clinical follow-up was performed in all patients.

RESULTS

Twenty-four patients experienced a primary event of cardiac death (n = 15), United Network for Organ Sharing status I (inotrope-dependent) heart transplant (n = 3) or urgent implantation of a LV assist device (n = 6). Doppler-derived dP/dt (dichotomized to > or = or <600 mm Hg/s; p = 0.0002) and -dP/dt (trichotomized to <450, 450 to 550 and >550 mm Hg/s; p = 0.0001) predicted event-free survival, as did Doppler-derived risk groups determined by the combination of the two (low risk, dP/dt > or = 600; intermediate risk, dP/dt < 600 and -dP/dt > or = 450; high risk, dP/dt < 600 and -dP/dt < 450; p = 0.0001). Multivariable analysis revealed Doppler-derived risk groups, intravenous inotrope requirement and blood urea nitrogen as significant independent predictors of outcome.

CONCLUSION

New Doppler indices of dP/dt, - dP/dt and risk groups defined by the combination of dP/dt and -dP/dt predict event-free survival in patients with CHF.

Doppler-derived left ventricular rate of pressure rise determination in presence of severe acute mitral regurgitation in pigs

Doppler-derived left ventricular (LV) rate of pressure rise (Dop LV DeltaP/Deltat) is described as an index of LV performance in the presence of mitral regurgitation (MR). This study was designed to define more accurately the accuracy of the method in the presence of severe MR. Ten pigs were anesthetized and monitored. MR was gradually created. At each grade of MR, preload was manipulated with the intent of modifying LV end-diastolic area value within a range of +/-20%. Concurrently, the mean left atrial pressure (LAP) was recorded, MR was quantified by the mitral to aortic velocity-time integral ratio (mitroaortic VTI ratio), Dop LV DeltaP/Deltat was calculated, and peak LV dP/dt was derived from LV catheterism data. During the procedure Dop LV DeltaP/Deltat gradually underestimated peak LV dP/dt. This difference was correlated to the mean LAP (P < 10(-5)) and mitroaortic VTI ratio (P < 10(-5)) and became clinically significant when the mean LAP was superior to 21 mm Hg.

Assessment of valvular regurgitation with Doppler echocardiography

Echocardiography is routinely performed for the evaluation of valvular regurgitation. Different applications of Doppler echocardiography have been successfully applied to detect and quantify valvular regurgitation. Recent advances in color Doppler made possible the study of the dynamic behavior of the regurgitant orifice and, along with continuous wave Doppler, can provide data on the regurgitant volume and fraction. Doppler echocardiography can also be used to follow serial changes in these hemodynamically important parameters after medical or surgical therapy.

Management of mitral regurgitation. Optimal timing for surgery

Chronic mitral regurgitation is a progressive disorder that can produce myocardial dysfunction in the absence of symptoms. Improvements in surgical techniques have resulted in earlier intervention, at times in asymptomatic patients. This article discusses the factors that influence prognosis, reviews the evidence supporting earlier intervention and provides guidelines for the management of patients with this lesion.

Treatment of chronic mitral regurgitation

BACKGROUND

Chronic, severe mitral regurgitation is a common clinical entity that can lead to progressive, irreversible left ventricular dysfunction. New information on the natural history of this condition, coupled with advances in surgical technique, have changed the roles of medical and surgical therapies.

METHODS

The current medical and surgical literature regarding chronic mitral regurgitation is critically reviewed.

RESULTS

There is no well-defined role for medical therapy in chronic mitral regurgitation. The goal of the treating physician is therefore to choose the optimal timing for surgical intervention. This process begins with noninvasive quantification of the degree of regurgitation. If severe, a careful search for signs or symptoms of impending left ventricular dysfunction should follow. Recent advances in surgical techniques for mitral valve repair allow for correction of the valvular defect with minimal mortality risk and improved preservation of ventricular function and are an impetus for early operative intervention. Mitral valve repair may also be beneficial in the setting of severe dilated cardiomyopathy.

CONCLUSIONS

The development of techniques for mitral valve repair has altered the treatment paradigm for severe mitral regurgitation. Surgical intervention before the onset of left ventricular dysfunction is recommended.

Doppler-derived left ventricular rate of pressure rise and inotropic requirements during mitral valve surgery

BACKGROUND

The estimation of left ventricular (LV) contractility is difficult in the presence of significant mitral regurgitation (MR). Prediction of LV performance after MR repair is even more problematic. The intraoperative Doppler-derived LV rate of pressure rise (LV delta P/delta t) analyzed before cardiopulmonary bypass (CPB) was presumed to be a useful predictive parameter for LV performance. Therefore, its relation to perioperative inotropic requirements (PIR) necessary for separation from CPB after surgical MR repair was investigated.

METHODS

Twenty-eight patients scheduled for surgical MR repair fulfilled the selection criteria. Pre-CPB LV delta P/delta t, pre-CPB echocardiographic LV fractional area change (LV FAC), and pre-CPB thermodilution-derived cardiac index (CI) were recorded. After MR repair, separation from CPB was performed with regard to standardized guidelines. PIR during the first 60 minutes following separation were recorded.

RESULTS

Pre-CPB LV delta P/delta t could be assessed in 22 patients. Pre-CPB LV delta P/delta t was 882 +/- 450 mmHg/sec, pre-CPB LV FAC was 49% +/- 9%, and pre-CPB CI was 2.0 +/- 0.2 L/kg/min. Pre-CPB LV delta P/delta t was significantly correlated with pre-CPB LV FAC (r = 0.56), and with pre-CPB CI (r = 0.72). Inotropic support was necessary in 16 patients (73%), and was best predicted by the pre-CPB LV delta P/delta t, by means of logistic regression (p = 0.026).

CONCLUSIONS

Doppler-derived LV delta P/delta t was assessable in most patients with severe chronic MR, and was the best intraoperative predictive parameter of post-CPB inotropic requirements after surgical MR repair.

Echocardiography for hemodynamic assessment of patients with advanced heart failure and potential heart transplant recipients

OBJECTIVES

This study sought to assess the accuracy of Doppler echocardiographic techniques for the determination of right heart catheterization hemodynamic variables in patients with advanced heart failure and in potential heart transplant recipients.

BACKGROUND

Doppler echocardiographic techniques permit the noninvasive acquisition of hemodynamic variables traditionally used for the assessment of patients with advanced heart failure and potential heart transplant candidates. However, the accuracy of these techniques has not been sufficiently well documented for clinical application in individual patients.

METHODS

Echocardiographic data required for estimation of mean right atrial, pulmonary artery and mean left atrial pressures and cardiac output were obtained. Right heart catheterization was performed immediately after Doppler echocardiographic data were acquired, before any intervention that might have altered the subject's hemodynamic status.

RESULTS

A complete Doppler echocardiographic hemodynamic data set was acquired in 21 (84%) of 25 subjects. For all variables, invasive and noninvasive hemodynamic values were highly correlated (p < 0.001), with minimal bias and narrow 95% confidence limits. An algorithm constructed from the noninvasive hemodynamic variable values identified all patients with adverse pulmonary vascular hemodynamic variables (i.e., transpulmonary gradient > or = 12 mm Hg, pulmonary vascular resistance > or = 3 Wood units or pulmonary vascular resistance index > or = 6 Wood units x m2). This algorithm identified 12 (71%) of 19 patients for whom right heart catheterization was unnecessary.

CONCLUSIONS

Doppler echocardiographic estimates of hemodynamic variables in patients with advanced heart failure are accurate and reproducible. This noninvasive methodology may assist with monitoring and optimization of medical therapy in patients with advanced heart failure and may obviate the need for routine right heart catheterization in potential heart transplant candidates.

Mitral regurgitation: a new clinical perspective

Mitral regurgitation is a common valvular heart disease, particularly in the elderly population. The timing of surgical repair is controversial, but recent literature suggests a new clinical perspective on the management of this disease. Despite receiving medical treatment and having few initial symptoms, patients with mitral regurgitation due to flail leaflets have an excess mortality rate (6.3% per year) and high morbidity. Ten years after mitral regurgitation has been diagnosed, 90% of the patients have either died or undergone an operation. After surgical correction of mitral regurgitation, left ventricular dysfunction is a frequent complication and is the cause of excess heart failure and mortality. This complication is due to preoperative left ventricular dysfunction but is incompletely predictable with use of current methods. Conversely, considerable progress in surgery has resulted in an extremely low operative mortality rate (about 1% in patients younger than 75 years of age) and high feasibility of valve repair, even in patients with anterior leaflet prolapse. These facts have led to the new perspective that early surgical correction (before occurrence of overt symptoms or left ventricular dysfunction) should be considered when patients are diagnosed with severe mitral regurgitation.

Comparison Between the Mean dP/dt During Isovolumetric Contraction and Other Echocardiographic Indexes of Ventricular Systolic Function

Echocardiographic assessments of ventricular function derived from estimates of the mean dP/dt during isovolumetric contraction (mean dP/dt(ic)) were compared with those obtained from measurements of the shortening fraction and the stress-velocity index (SVI). Mean dP/dt(ic) correlated well with the shortening fraction, r = 0.74, P < 0.0001. Furthermore, 10 out of 11 patients with mean dP/dt(ic) below 800 had a shortening fraction < 0.28, whereas all patients with a mean dP/dt(ic) > 1000 mmHg/sec had a shortening fraction > 0.28. A good correlation also existed between mean dP/dt(ic) and the SVI, r = 0.73, P < 0.0001. Nine out of 11 patients with a mean dP/dt(ic) < 800 mmHg/sec had an SVI > 2 standard deviations below normal, whereas all patients with mean dP/dt(ic) > 1000 mmHg/sec had normal or increased SVI. The correlation between mean dP/dt(ic) and the SVI was strengthened when mean dP/dt(ic) was adjusted for heart rate and preload. Hence, assessments of ventricular function derived from measurements of mean dP/dt(ic) appear to agree well with those provided by the shortening fraction and SVI. Because the determination of mean dP/dt(ic) is not hampered by unusual anatomy or wall motion (conditions which compromise the validity of the shortening fraction and SVI), mean dP/dt(ic) may be a good index of ventricular function in cases where measurements of the shortening fraction and SVI would be unreliable.

[Usefulness of the Doppler index delta P/delta t in the evaluation of left ventricular systolic dysfunction]

INTRODUCTION AND OBJECTIVES

It has been shown that the delta P/delta t index, derived from the continuous Doppler mitral regurgitation signal correlates strongly with dP/dt. This study evaluates the feasibility, reproducibility and correlation of the index with ejection fraction and other conventional echocardiographic parameters.

MATERIAL AND METHODS

One hundred and ten patients with mitral regurgitation demonstrated by colour Doppler were studied. delta P/delta t were calculated by the ratio between the interval of pression between two points of the Doppler signal (-1 and -3 m/s; 32 mmHg, applying the modified Bernouilli equation) and the interval of time (s) which separates both. Ejection fraction was measured in 70 patients by non-echocardiographic methods (isotopic ventriculography, n = 52, and angiography, n = 18).

RESULTS

The index was feasible in 91 cases, the variability of intra and interobserver was 5% and 7% respectively. The correlation between delta P/delta t and ejection fraction was significant although weak (r = 0.59; p < 0.001; n = 70). It was better in the group of dilated idiopathic myocardiopathy (r = 0.72; p < 0.001; n = 18) than in the group of myocardial infarction (r = 0.54; p < 0.01; n = 25). No significant correlation was founded in the cases with mitral rheumatic valvulopathy. Regarding to the echocardiographic parameters, the best correlation was obtained with end systolic diameter (r = -0.64; p < 0.001; n = 49). Finally, a value of delta P/delta t < 1,000 mmHg/s predicted the existence of left ventricular systolic dysfunction with high accuracy (84%), sensitivity (80%) and specificity (92%).

CONCLUSIONS

High feasibility when mitral regurgitation exists, adequate reproducibility and heightened precision in diagnosing left ventricular systolic dysfunction, are characteristics which make delta P/delta t useful in the echocardiographic routine practice.

Left ventricular function after valve repair for chronic mitral regurgitation: predictive value of preoperative assessment of contractile reserve by exercise echocardiography

OBJECTIVES

We evaluated the value of preoperative assessment of left ventricular contractile reserve in predicting ventricular function after valve repair for minimally symptomatic mitral regurgitation.

BACKGROUND

The optimal timing for operation in minimally symptomatic patients with significant mitral regurgitation is controversial. Accurate preoperative assessment of left ventricular function is difficult, and the ability to predict postoperative function is limited. Previous studies in patients undergoing mitral valve replacement may not be applicable in the present era of valve repair.

METHODS

We performed exercise echocardiography in 139 patients with isolated mitral regurgitation and no coronary disease, 74 of whom subsequently underwent uncomplicated valve repair. We measured rest left ventricular end-systolic dimension, end-systolic wall stress and positive first derivative of left ventricular pressure (dP/dt). End-diastolic and end-systolic volumes and ejection fraction were measured preoperatively at rest, immediately after exercise and postoperatively.

RESULTS

Ejection fraction decreased postoperatively to 55 +/- 10% from a rest preoperative value of 64 +/- 9% (p < 0.001). Compared with patients with a postoperative ejection fraction > or = (n = 56), patients with postoperative ejection fraction < 50% (n = 18) had a significantly lower preoperative exercise ejection fraction (57 +/- 11% vs. 73 +/- 9%, p < 0.0005), a larger exercise end-systolic volume index (32 +/- 8 vs. 18 +/- 7 cm3/m2, p < 0.0005) and a lower change in ejection fraction with exercise (-4 +/- 8% vs. 9 +/- 10%, p < 0.005). Preoperative rest indexes, including dP/dt, end-systolic wall stress and end-systolic volume index were less predictive, whereas exercise capacity, rest ejection fraction and end-systolic dimension were not predictive of post-repair ejection fraction. An exercise end-systolic volume index > 25 cm3/m2 was the best predictor of postoperative dysfunction, with a sensitivity and specificity of 83%.

CONCLUSIONS

In minimally symptomatic patients with mitral regurgitation, latent ventricular dysfunction may be indicated by a limited contractile reserve, manifest at exercise as an inadequate increase in ejection fraction and a larger end-systolic volume. These variables may also be used to predict left ventricular function after repair.

Newer Doppler measures of left ventricular diastolic function

Left ventricular (LV) diastolic dysfunction is an important cause of heart failure, and recent advances in the application of Doppler techniques allow a semiquantitative assessment of LV diastolic performance. This review discusses the use of Doppler echocardiography in the comprehensive assessment of LV diastolic function and performance in terms of the normal mitral and pulmonary venous flow profiles, their physiologic basis, and alterations in diseased states. There is also a discussion on the newer aspects of mitral flows such as relative durations of mitral A and pulmonary vein AR waves, E- and A- wave propagation inside the LV with their hemodynamic correlates, and derivation of ventricular dP/dt and Tau from the mitral regurgitation velocity profile. Analysis of these flow profiles and the other Doppler measures alluded to above allow one to make a fairly precise hemodynamic assessment of a patient in terms of left atrial pressure, LV relaxation and stiffness and the profile of LV diastolic pressure in terms of pre- 'a' wave and 'a' wave pressures and ventricular end-diastolic pressure.

Echocardiography assessment of left ventricular function in the critically ill

Echocardiography is fast becoming the technique of choice for noninvasive evaluation of left ventricular function in the critically ill patient. Current technology allows for assessment of overall left ventricular performance and for diastolic and systolic function. Doppler technology has greatly enhanced the diagnostic capability of two-dimensional echocardiography. The critical care physician should be aware not only of currently available techniques, but also those which will be used in the routine care of the critically ill subject in the foreseeable future.