Directional Doppler in Cardiology: A 50-Year Journey.

In 1968, while cardiologists were focused on cardiac structures imaged by ultrasound, Daniel Kalmanson in Paris, France, devised a new ultrasonic modality, directional continuous-wave Doppler, enabling him to record instantaneous cardiovascular blood flow velocities with recognition of their direction (relative to the transducer) in vessels. An innovative presentation of Doppler data also made velocity traces physiologically understandable. Following the noninvasive study of the arterial and venous beds, flow velocity in the right (1969) and left (1970) cardiac chambers was studied by means of a directional Doppler catheter. The curtain was then raised for the renewal of our pathophysiologic understanding of cardiac dynamics and the adoption of a new methodology. Technological evolution paved the way for clever researchers to pioneer important advances, diversifying the technique. Guided by the early principles, which are still valid in 2018, directional Doppler finally gained acceptance from the entire scientific community.

[A history of the clinical research in cardiology]. / Une histoire de la recherche clinique en cardiologie.

On January 21 1968, nearly an half-century ago, a small Parisian group of cardiologists presented a directional Doppler prototype making possible the detection of forward and backward flows in the arteries. This princeps report, rapidly followed by the Directional Doppler recording of intracardiac flows, has upset the traditional approach to cardiovascular pathophysiology and launched a new examination method that will spread upon the whole word. Single CNRS researcher among this group of clinical cardiologists, Dr Colette Veyrat recalls this early period….

The glorious years leading Doppler flow to the heart, the odyssey of the pioneers!

This review pays tribute to those pioneers in Doppler flow during an early and exciting period ranging from the end of the 1960s to the 1990s. Three major 'approaches' contributed to what is nowadays built into every patient's investigation. The source was Daniel Kalmanson, who developed flow directionality, assigning a physiological meaning to the recordings. This was the first time Doppler flow was used on the heart, providing new insights in cardiac pathophysiology. The second approach relied on the Norwegian group who applied the laws of physics to fluid dynamics. Simplification of the formula provided a new non-invasive approach enabling quantification of valvular lesions and haemodynamic measurements. This new tool pushed back previous routine catheterisation. To crown it all, the introduction of colour Doppler flow, mainly relying on the Japanese groups, overcame the long-lasting scepticism of the scientific community: cardiologists started to "believe" in the Doppler technique. Other innovative pioneers around the world joined the three groups to develop this new field of cardiology. At the turning of the new millennium, the Doppler technique is mature, through a strong methodology. Convergence of the three original approaches for mutual benefit, constant update of examination modalities according to improved technology, and new insights into cardiac dynamics, are the three cornerstones supporting this methodology. They should contribute to keep it alive and efficient, independently of the imaging modality of the future.

Daniel Kalmanson, pioneer of intracardiac Doppler exploration in 1969: Emphasis on the first mitral and tricuspid flow velocity recordings.

Intracardiac Doppler flow patterns remained unexplored until 1969, when Daniel Kalmanson could specify the features and physiological interpretation of intracardiac traces by mounting the new directional continuous-wave Doppler device on a catheter-tip. Within a year of time, he defined the continuum of changes from a three-waved venous inlet pattern (two positive S and D, one negative A) to a single systolic wave S at the arterial outlet. Moreover, the first descriptions of mitral and tricuspid Doppler flow traces were reported on man from 1969 (right heart) to 1972 (left heart). Pathophysiologic significance of their fundamental changes in pattern was specified in patients. Major clinical advances resulted from the integration of flow phenomena into physician's medical reasoning.

Renewed interest in preejectional isovolumic phase: new applications of tissue Doppler indexes: implications to ventricular dyssynchrony.

There is renewed interest in isovolumic contraction (IC) in tissue Doppler echocardiography of the myocardial walls, which is revisited in this editorial with new regional velocity data. The aims are to recall traditional background information and to emphasize the need to master the rapidly evolving tissue Doppler procedures for the accurate display of brief IC. IC, a preejectional component of great physiologic interest, is very demanding in terms of ultrasound technology. The onset and end of its motion velocities should be unambiguously defined versus the QRS complex and ejection wall motion. This is a prerequisite for exploiting the new information as guidance toward new therapeutic strategies from a practical viewpoint. However, IC preload dependence should be kept in mind, because of its limited potential for contractility studies. Finally, when only duration measurements are made in the assessment of ventricular dyssynchrony, regional preejectional duration is the pertinent tool to single out the onset of ejection local wall motion.

Detection of prominent left anterior descending coronary artery stenosis for patients with stable angina using Doppler tissue echocardiography.

The midseptum has an elective left anterior descending coronary artery (LAD) supply. Septal peak velocity (PkV) and myocardial velocity gradient (MVG) were studied at rest with M-mode Doppler tissue echocardiography during the cardiac cycle including the septal active relaxation (SAR) outward wall motion preceding isovolumic relaxation. In all, 33 patients had significant multivessel coronary artery disease. Group A (15 patients) had prominent LAD stenosis. Group B (18 patients) had prominent circumflex (15) or right (3) coronary artery stenoses. The goal was to detect a prominent LAD stenosis. During SAR, sensitivity to detect a prominent LAD stenosis was 86% for PkV < 20 mm/s and 80% for MVG < 1.1 s(-1); specificity was 83% for both variables. During systole, sensitivity was 86% with a 55% specificity for MVG < 2.0 s(-1), whereas sensitivity was 73% and specificity 66% for PkV < 30 mm/s. Areas under receiver operating characteristic curves were over 0.90 during SAR and only 0.70 for PkV and 0.80 for MVG during systole. In multivessel coronary artery disease, SAR variables better identified a prominent LAD stenosis than systolic variables. Moreover, SAR PkVs were informative per se, whereas systole required MVG calculation.

Tissue Doppler echocardiographic and color M-mode estimation of left atrial pressure in infants.

OBJECTIVES: Using recorded flow and tissue Doppler, we evaluated the relation of peak velocity of early transmitral Doppler filling (E)/early diastolic velocity of the lateral mitral annulus (Ea) ratio and of E/flow propagation velocity (Vp) ratio to mean left atrial pressure in infants after surgery for congenital heart disease. DESIGN: Experimental design. SETTING: Pediatric intensive care unit. PATIENTS: Thirty-seven infants aged 4 (3-8) months. INTERVENTIONS: Patients underwent postoperative invasive hemodynamic monitoring with simultaneously obtained Doppler measurements. MEASUREMENTS AND MAIN RESULTS: Values are expressed as median (25th-75th percentiles). Heart rate was 145 (135-157) beats/min. Left atrial pressure was 10 (8-12) mm Hg with E/Ea 16 (12-19) and E/Vp 1.9 (1.3-2.4). E/Ea and E/Vp ratios were higher in patients with left atrial pressure >10 mm Hg (n = 18), than in patients with left atrial pressure < or =10 mm Hg (n = 19) (E/Ea, 16 [15-25] vs. 12 [9-17], p = .01; E/Vp, 2.3 [1.9-2.8] vs. 1.4 [1-1.9]. respectively, p = .001). At a cutoff point of 15, E/Ea sensitivity for left atrial pressure >10 mm Hg was 17 of 18 (94%) with specificity 13 of 18 (72%). At a cutoff point of 2, E/Vp sensitivity for left atrial pressure >10 mm Hg was 15 of 18 (83%) with specificity 16 of 18 (89%). Areas under the receiver operating characteristic curves were 0.76 (E/Ea) and 0.83 (E/Vp). CONCLUSIONS: Doppler ratios might be considered as promising noninvasive tools for left atrial pressure evaluation in infants after cardiac surgery.

A new Doppler tissue ratio to revisit systole: the pre-ejectional isovolumic to ejectional velocity ratio-application to aging.

Most diagnostic applications of Doppler tissue echocardiography rely on peak (Pk) velocity (V) values of single variables or myocardial V gradient. Whereas age-related changes in diastolic V are well-known, previous Doppler tissue echocardiography studies of systolic function showed no age effect for pre-ejectional (Ej) isovolumic (PEI) and Ej inward wall motion Pk V. In addition to myocardial V gradient, ratios were calculated between PEI and Ej Pk V, and mean V averaged over systole (PEI/Ej V ratios) at each layer of the posterior wall using M-mode color on two control groups: A (27 +/- 5 years) and B (54 +/- 10 years). The only changes were for PEI/Ej V ratios (mean V endocardial 21 +/- 7% vs 34 +/- 20%, P = .01; mean V epicardial 27 +/- 8% vs 40 +/- 18%, P = .006; Pk epicardial V 21 +/- 10% vs 30 +/- 16%, P = .04 for groups A and B, respectively). Correlation versus age were r = 0.52 and P = .005 (mean V endocardial), r = 0.50 and P = .007 (mean V epicardial), and r = 0.32 and P = .03 (Pk epicardial V). PEI/Ej V ratios and mean V studied in separate layers showed that the new systolic approach had advantages over single variable or Pk V to study age-related changes.

Clinical relevancy of the myocardial velocity gradient: limitations of a binary response.

BACKGROUND: Doppler tissue echocardiographic myocardial velocity gradient (MVG) overcomes translational or tethered motion effects. Diagnostic applications rely on MVG numeric value, an instantaneous value calculated at peak endocardial velocity. Our aim was to test the clinical relevancy of MVG for patients with dilated cardiomyopathy (CM) at rest. Efficiency of MVG, as a marker of the underlying mechanism, ischemic or nonischemic, was compared with that of mean velocities averaged over a cycle. METHODS: Peak and mean velocities were measured and MVG calculated during ejection, and early and late diastole, in the endocardium and epicardium on color M-mode Doppler tissue echocardiographic parasternal recordings of the posterior wall, simultaneously imaged with the septum. The population consisted of 34 patients with similar clinical presentation (left ventricular ejection fraction < 40%, left ventricular end-diastolic diameter > 6 cm, and proven ischemic [14] or nonischemic [20] dilated CM) and 16 control subjects. RESULTS: Doppler tissue echocardiography data significantly differed between control subjects and all patients with CM. Between patients, the only significant differences were found at the posterior wall for mean velocities at the epicardium in systole (9 +/- 4 mm/s for ischemic vs 14 +/- 5 mm/s for nonischemic, P =.002), and at both layers in early diastole (endocardium, 14 +/- 9 vs 29 +/- 12 mm/s, P =.0004; epicardium, 12 +/- 4 vs 22 +/- 11 mm/s, P =.002; ischemic vs nonischemic CM, respectively). CONCLUSION: Specific features of CM were characterized by myocardial velocity changes studied layer by layer throughout a phase. The binary response of transient peak MVG could not reach this goal.

Dynamic myocardial velocity changes between phases of the cardiac cycle.

The purpose of this study was 1. to define relationships between myocardial velocities according to phases and the range of dynamic phasic changes in controls using tissue Doppler echocardiography (TDE); 2. to compare the usefulness of dynamic changes vs. peak velocities alone on controls and patients. Peak velocity changes between phases were studied by colour M-mode TDE in the posterior wall from pre-ejection to systole (ejectional wall velocity increase) and from ejection to early diastole (early diastolic wall velocity increase) in 17 age-matched controls and a group of 30 patients with dilated cardiomyopathies (CMy) consisting of ischaemic (14) and nonischaemic (16) CMy with similar clinical and echocardiographic presentations. Systolic were correlated with early diastolic peak velocities (r = 0.79 p < 0.0001). Velocity values were significantly lower in patients than in controls (p < 0.001) as well as dynamic ejectional (p = 0.02) and early diastolic (0.03) increases. Dynamic changes were closely similar to controls (74 +/- 7%, 46 +/- 14%) in nonischaemic CMy (66 +/- 18%, 39 +/- 10% NS, respectively), but markedly reduced in ischaemic CMy (28 +/- 59%, and 26 +/- 31%, p = 0.005 and p = 0.06 vs. nonischaemic CMy, respectively). Of patients with ischaemic CMy, 78% had an ejectional increase < 40% and/or an early diastolic increase < 25%. Thus, correlation exists between systolic and early diastolic velocities. Normal range of dynamic changes was defined in an elderly population. Results suggest that velocity dynamics might be more informative than peak velocities alone to show left ventricular dysfunction.

Myocardial time intervals preceding left ventricular filling in chronic coronary artery disease: value of a decreased septal ejection time.

The aim was to assess the capabilities of a two-segment myocardial recording to recognize patients with an underlying chronic ischemic process as a fast screening from controls, prior to the usual segment-to-segment tissue Doppler echocardiographic assessment of ischemia. Ischemia generates systolic and relaxation abnormalities. A flow Doppler index of global systolic and diastolic myocardial performance was recently drawn from time durations studied by coupling isovolumic relaxation (IR) to preejection (PEP)/ejection (ET) ratio (PEP/ET). We derived a similar tissue Doppler approach to the period preceding the left ventricular filling: PEP', the ejectional inward wall motion representing ET' and the prefilling (PreFg) period ranging from the end of ET' to the onset of the outward wall motion approximating IR, were measured and ratios calculated between variables. Spectral tissue Doppler was applied to septal and posterior walls of 28 patients with proven chronic coronary artery disease and preserved left ventricular function and of 12 age-matched controls. Data were compared with global flow data. Global information did not differentiate both groups, save for IR (sensitivity 32%, specificity 57%). In patients, tissue Doppler mean values of single variables (P=0.004-0.0006) and ratios (P=0.03-0.002) significantly differed from controls. Moreover, septal ET' differentiated 13 patients with one-vessel (219+/-34 ms) from 10 with two-vessel disease (158+/-70 ms, P=0.01). Sensitivity and specificity of a septal ET'<190 ms for a two-vessel disease were 80%. The two-segment tissue Doppler echocardiographic study provided a rapid screening of patients versus controls and helped to predict the number of diseased vessels.

Quantitative Analysis of Tissue Doppler Data.

A visual qualitative analysis of color Doppler myocardial images cannot show the low velocity changes in myocardial walls, and a quantitative analysis of tissue Doppler data is mandatory for an analysis of color Doppler myocardial recordings, including an assessment of myocardial velocity gradient across the thickness of the wall. Measurement of myocardial velocity in each pixel should provide access to a broader pathophysiological insight into regional contraction across wall thickness and into all myocardial segments throughout the cardiac cycle.