Diastolic Velocity Time Integral Research Articles

Hypertrophic Cardiomyopathy—Septal Perforator Arteries Doppler Flow Dynamics

Patients with hypertrophic cardiomyopathy (HCM) have been shown to exhibit abnormal diastolic vessel flow; however, flow pattern profiles and their possible association with different grades of diastolic dysfunction have not been studied. Color Doppler two-dimensional echocardiography permits visualization of the septal perforator arteries, and pulsed-wave Doppler allows recording of diastolic septal artery flow (SAF). Through routine visualization of the septal perforator arteries and acquisition of SAF, we noticed 3 patterns of SAF in patients with HCM. In this study, we aimed to assess the feasibility of the acquisition of SAF and to describe types of SAF in an HCM cohort and their associations with diastolic function. We reviewed two-dimensional echocardiograms and the electronic records of 108 patients with HCM in whom septal artery color and spectral Doppler had been performed. The peak diastolic and end-diastolic velocities, diastolic slope, diastolic flow time-velocity integral, and systolic flow reversal of the septal perforator arteries were recorded with pulsed-wave Doppler. Echocardiographic and clinical characteristics were analyzed. A reproducible pulsed-wave Doppler tracing was recorded in 54% of patients with HCM. Three distinct patterns of SAF were identified: type 1-smooth, linear holodiastolic velocity decrease; type 2-with presence of an atrial dip; and type 3-biphasic velocity decrease with an early, rapid diastolic slope and a mid-to-late gentle slope. These 3 SAFs correlated with different grades of diastolic dysfunction. Septal artery flow could be detected in more than 50% of patients with HCM. Three distinct types of SAF were identified, correlating with different grades of diastolic dysfunction. These 3 types of SAF can provide additional information about left ventricular end-diastolic pressure and diastolic function in patients with HCM in whom diastolic function may be difficult to determine.

Association between coronary flow and aortic stenosis during transcatheter aortic valve implantation.

In patients with aortic stenosis (AS), the coronary flow reserve decreases even in the absence of epicardial coronary artery stenosis. Systolic coronary flow reversal (SFR) reflecting reduced coronary microcirculation, often seen in patients with severe AS, has a potential negative impact on the pathogenesis of cardiac dysfunction. However, there are limited data on the relationship between the severity of AS and SFR, as well as on the benefits of transcatheter aortic valve implantation (TAVI). The aim of this study was to evaluate the relationship between the severity of AS and efficacy of TAVI in improving SFR. Consecutive patients with AS who had undergone TAVI using transoesophageal echocardiography (TEE) from November 2020 to February 2022 were prospectively enrolled. Coronary flow in the left anterior descending artery as well as the aortic valve peak velocities, and the mean aortic valve pressure gradients (AVPGs), indicating the severity of AS, were measured using intraprocedural TEE before and after TAVI. The following parameters were measured as coronary flow: systolic and diastolic peak velocity (cm/s) and systolic and diastolic velocity-time integral (VTI) (cm). SFR was defined as the presence of a reversal coronary flow component in systole. The enrolled patients were classified into two groups according to the presence or absence of SFR before TAVI. A total of 25 patients were included: 13 had SFR and 12 who had no SFR, before TAVI. Patients with SFR had significantly higher aortic valve peak velocities (451.1±45.9 vs. 372.1±52.1cm/s; P<0.001) and mean AVPGs (49.2±14.5 vs. 30.3±11.6mmHg; P=0.002) than those without. The optimal binary cut-off aortic valve peak velocity values and the mean AVPG associated with the presence of SFR before TAVI were >410.0cm/s (specificity, 75.0%; sensitivity, 92.3%) and >37.4mmHg (specificity, 83.3%; sensitivity, 92.3%), respectively. After TAVI, SFR immediately disappeared in 11 of 13 patients with SFR (84.6%). Overall, the systolic coronary VTI significantly increased after TAVI (2.0±4.7 vs. 6.4±3.2cm, P<0.001), and this increase was greater in patients with SFR than in those without SFR before TAVI (interaction P=0.035). SFR was found to be associated with the severity of AS and with a greater increase in systolic coronary flow immediately after TAVI.

Diastolic flow in the left ventricular outflow tract - A normal physiological and underappreciated echocardiographic finding.

Diastolic waveforms in the left ventricular outflow tract (LVOT) are commonly observed with Doppler echocardiography. The incidence and mechanism are not well described. This was a retrospective observational study of 186 adult patients, athletes and non-athletes, free of known cardiac disease, presenting for comprehensive transthoracic echocardiography at a research institute. We aimed to evaluate the incidence and echocardiographic associations between LVOT diastolic waveforms. Left ventricular outflow tract early to mid-diastolic waveforms were present in 100% of athletes and 95% of non-athletes. The LVOT diastolic velocity time integral was larger in athletes than non-athletes with a mean 8.3 cm (95% CI (7.6-8.9)) vs. 5.1 cm (4.4-5.9) (P < 0.0001). Multivariate predictors of this diastolic waveform were age (P = 0.002), slower heart rate (P = 0.035), higher stroke volume (P = 0.003), large mitral E (P = 0.019) and higher E/e' (P = 0.015). An LVOT early diastolic wave is a normal physiological finding. It is related to a flow vortex redirecting diastolic mitral inflow around anterior mitral valve leaflet into the LVOT. Early to mid-diastolic LVOT waves are present in almost all patients but more prominent in young athletes than non-athletes. Diastolic LVOT waves increase with younger age, slower heart rate, larger stroke volume and enhanced diastolic function.

Echocardiographic findings for improved prenatal diagnosis of aortic coarctation with ventricular septal defect.

Accurate prenatal diagnosis of coarctation of the aorta (CoA) associated with ventricular septal defect (VSD) remains challenging. The objective of the study was to identify which Doppler and/or two-dimensional sonographic findings are most useful for predicting fetal CoA/VSD. A retrospective cohort study identified 35 fetuses with suspected CoA/VSD. Prenatal imaging characteristics included the right ventricular/left ventricular, pulmonary artery (PA)/aorta ratio, aortic isthmus (AOI) Z score, diastolic velocity-time integral (VTID), and systolic velocity-time integral (VTIS) at the AOI. The area under the receiver operating characteristic curve (AUC), integrated discrimination improvement (IDI), and net reclassification improvement (NRI) were calculated. Significant differences in the PA/AO, VTID, VTID/VTIS, VTID/VTIS, VTID/(VTID + VTIS), and AOI Z score between the true CoA group and false positives were found. When associated with VSD, the VTID/VTIS and VTID/(VTID + VTIS) had the highest AUC (0.97, 95% confidence interval: 0.84-1.00), with 88.46% sensitivity and 100.00% specificity for predicting the true CoA. The AOI Z score had the highest sensitivity (92.31%). Adding the VTID/VTIS to the AOI Z score significantly improved the performance (IDI, 50%; NRI, 82%; P < 0.05), with an improvement in specificity (77.78% vs. 55.56%; non-Event P = 0.008) without sacrificing sensitivity (96.15% vs. 92.31%; Event P = 0.564). In fetuses with suspected CoA associated with VSD, the quantitativespectral Doppler metric aided accurate detection of the fetal CoA, with reduced false positives. The conventional AOI Z score plus spectral Doppler metric may improve the overall diagnostic accuracy of CoA/VSD.

The Diastolic and Systolic Velocity-Time Integral Ratio of the Aortic Isthmus Is a Sensitive Indicator of Aortic Coarctation in Fetuses

Prenatal diagnosis of coarctation of the aorta (CoA) is challenging and is affected by high false-positive and false-negative rates. The aim of this study was to identify sonographic criteria to improve the identification of fetal CoA. A retrospective review was conducted of subjects with prenatal suspicion for CoA who also had postnatal follow-up. Sixty-nine fetuses were identified with possible CoA, and 47 normal fetuses were selected as control subjects. Retrospective measurements of right ventricular/left ventricular ratio, pulmonary artery/aorta ratio, aortic isthmus (AOI) Z score, diastolic velocity-time integral (VTID), and systolic velocity-time integral (VTIS) at the AOI were recorded. Receiver operating characteristic curve analysis identified the parameter most predictive of postnatal CoA. When comparing subjects with (n=31) and without (n=38) CoA, significant differences were detected for the AOI Z score, VTID, VTID/VTIS ratio, and VTID/(VTID+VTIS) ratio (P<.001). The areas under the receiver operating characteristic curve were 0.92, 0.92, 0.78, 0.74, 0.71, and 0.68 for the VTID/VTIS ratio, VTID/(VTID+VTIS) ratio, VTID, AOI Z score (sagittal view), AOI Z score (three-vessel tracheal view), and pulmonary artery/aorta ratio, respectively. There was a 25% (95% CI, 14%-35%) improvement in the area under the curve after adding the VTID/VTIS ratio to the basic model (AOI Z score [sagittal view]), and this ratio (after transformation) showed significantly better discrimination and reclassification ability for determining CoA. The pulmonary artery/aorta ratio, VTID, VTID/VTIS ratio, and VTID/(VTID+VTIS) ratio were stable throughout the normal fetal developmental period in this study. In cases with suspected prenatal diagnosis of CoA, evaluation of spectral Doppler measurements, such as the VTID/VTIS ratio, may enhance the accuracy of diagnosis with fetal echocardiography.

Usefulness of Intraprocedural Pulmonary Venous Flow for Predicting Recurrent Mitral Regurgitation and Clinical Outcomes After Percutaneous Mitral Valve Repair With the MitraClip

ObjectivesThe aim of this study was to determine the prognostic value of pulmonary venous (PV) flow during MitraClip implantation. BackgroundThe clinical significance of PV flow information during MitraClip implantation is unknown. MethodsA total of 300 patients who underwent MitraClip implantation and in whom the measurement of PV flow was completed using intraprocedural transesophageal echocardiography were retrospectively reviewed. The optimal threshold of the ratio of systolic velocity-time integral (Svti) to diastolic velocity-time integral (Dvti) ratio after MitraClip placement for major adverse cardiovascular events (all-cause death, redo MitraClip implantation, mitral valve surgery, and heart transplantation) during 12 months was assessed. The best cutoff ratio was 0.72. Patients were divided into 2 groups using this cutoff ratio (low Svti/Dvti, n = 91; high Svti/Dvti, n = 209). ResultsFollowing mitral regurgitation reduction by MitraClip placement, Svti increased in the both groups. The frequency of mitral regurgitation 3/4+ immediately after MitraClip implantation, at 1-month follow-up, and at 12-month follow-up was significantly higher in patients with low Svti/Dvti ratios than in those with high Svti/Dvti ratios (after MitraClip placement, 5.5% vs. 0%; p < 0.001; at 1 month; 26% vs. 5.2%; p < 0.001; at 12 months, 18% vs. 5.3%; p = 0.006). Major adverse cardiovascular events during 12 months were significantly higher in patients with low Svti/Dvti ratios than in those with high Svti/Dvti ratios (23% vs. 6.2%; p < 0.001). Multivariate analysis demonstrated that low Svti/Dvti ratio was significantly associated with major adverse cardiovascular events during 12 months after adjustment for age, baseline renal function, and mean transmitral pressure gradient (adjusted hazard ratio: 4.00; 95% confidence interval: 2.02 to 8.23; p < 0.001). ConclusionsPV flow information in the catheterization laboratory immediately after MitraClip implantation predicted recurrent mitral regurgitation and worse long-term outcomes.

Indexing peak rapid filling velocity to both relaxation and filling volume to estimate left ventricular filling pressures.

The peak transmitral velocity/peak mitral annular velocity (E/e') ratio has been used as a left ventricular (LV) filling pressure (LVFP) correlate. However, the E/e' and its changes with haemodynamic alterations have not always correlated with changes in LVFP's. We hypothesized that indexing E/e' to a measure of LV filling volume may enhance the correlation with LVFP and LVFP changes. We summarized previously obtained haemodynamic and Doppler echo data in 137 dogs with coronary microsphere embolization induced-chronic LV dysfunction prior to and following haemodynamic induced alterations in LVFP's. E/e' values were obtained as E*tau where tau is the inverse logarithmic LV pressure decay. E*tau was indexed to LV filling volume by dividing by the diastolic time velocity integral (DVI) and correlated with LV mean diastolic pressure (LVmDP). Similarly, the relationship of E/e' and E/e'/DVI to LV pre A wave pressure was evaluated in 84 patients by invasive haemodynamics and Doppler echo. Combining data from all interventions, LVmDP correlated with E*tau (r = 0.408) but more strongly with E*tau/DVI (r = 0.667, z = 3.03, P = 0.0008). The change in LVmDP correlated with the change in E*tau/DVI (r = 0.742) more strongly than E*Tau (r = 0.187, Z = 4.01, P < 0.0001). In the patient cohort, E/e' was modestly correlated with LV pre A wave pressure (r = 0.301) but more strongly correlated with E/e'/DVI (r = 0.636, z = 2.36, P = 0.0161). Indexing E to both LV relaxation and filling volume results in a more robust relation with LVFP's and with LVFP changes.

Relation Between Pulmonary Venous Flow and Left Atrial Pressure During Percutaneous Mitral Valve Repair With the MitraClip

Pulmonary venous (PV) flow may provide valuable information in terms of the severity of mitral regurgitation and left atrial (LA) pressure. We sought to find PV flow determinants of LA pressure during MitraClip procedure. We analyzed 575 PV flows in 290 patients using transesophageal echocardiography before and after MitraClip procedure. We measured peak systolic velocity (Sv), diastolic velocity (Dv), systolic velocity time integral (Svti), diastolic velocity time integral (Dvti), and those systolic to diastolic ratio as PV flow parameters. Systolic PV flow velocity was lower than diastolic PV flow velocity before the procedure, but systolic PV flow velocity markedly increased after the procedure. Peak Sv/Dv ratio and Svti/Dvti ratio after the procedure were significantly higher than those before the procedure (peak Sv/Dv; 1.06 [inter-quartile range (IQR) 0.73 to 1.34] vs 0.32 [IQR 0.03 to 0.55], p <0.001, Svti/Dvti; 1.06 [IQR 0.76 to 1.61] vs 0.26 [IQR 0.02 to 0.51], p <0.001). Peak Sv/Dv ratio and Svti/Dvti ratio were negatively correlated with mean LA pressure and LA pressure V wave, respectively (peak Sv/Dv ratio; r = -0.50 and r = -0.59, Svti/Dvti ratio; r = -0.47 and r = -0.58, p <0.001). In receiver operating characteristics curve assessing the ability of PV flow to predict mean LA pressure ≥20 mm Hg after the successful procedure, the area under the curve of peak Sv/Dv ratio was 0.76 (p <0.001). Peak Sv/Dv ratio <0.98 best predicted LA pressure ≥20 mm Hg with 77% sensitivity and 71% specificity. In conclusion, systolic PV flow velocity immediately increased in response to mitral regurgitation reduction during MitraClip procedure. PV flow velocity, specifically systolic to diastolic ratio, was useful to evaluate invasively determined LA pressure.

Pulsed-Wave Doppler Recordings in the Proximal Descending Aorta in Patients with Chronic Aortic Regurgitation: Insights from Cardiovascular Magnetic Resonance

The pulsed-wave Doppler recording in the descending aorta (PWDDAO) is one of the parameters used in grading aortic regurgitation (AR) severity. The aim of the present study was to investigate the assessment of chronic AR by PWDDAO with insights from cardiovascular magnetic resonance (CMR). This prospective study comprised 40 patients investigated with echocardiography and CMR within 4hours either prior to valve surgery (n=23) or as part of their follow-up (n=17) due to moderate or severe AR. End-diastolic flow velocity (EDFV) and the diastolic velocity time integral (dVTI) were measured. The appearance of diastolic forward flow (DFF) was noted. Phase-contrast flow rate curves were obtained in the DAO. Twenty-five patients had severe and eight had moderate AR by echocardiography (seven were indeterminate). The EDFV was below the recommended threshold (>20cm/sec) in 13 patients (52%) with severe AR. Lowering the EDFV threshold (>13cm/sec) and with a dVTI threshold >13cm showed negative likelihood ratios of 0.27 and 0.09, respectively. Detection of DFF with PWDDAO identified a nonuniform velocity profile by CMR with positive and negative likelihood ratios of 7.0 and 0.19, respectively. The relation between EDFV and DAO regurgitant volume (DAO-RVolCMR) was strong in patients without (R=0.88) and weak in patients with DFF (R=0.49). The DAO-RVolCMR as a percent of the total RVolCMR decreased with increasing ascending aorta (AAO) size and increased with increasing AR severity. Our findings suggest that PWDDAO provides semiquantitative parameters useful to assess chronic AR severity. The limitations are related to nonuniform velocity contour and variable degree of lower body contribution, which depends on AR severity but also on the AAO size.

Coronary Flow Parameters Assessed by Transesophageal Echocardiography in Patients with Coronary Artery Ectasia Baseline Measurements and the Effects of Intravenous Verapamil

Background and rationale: Coronary artery ectasia (defined as luminal dilatation 1.5 to 2 times the adjacent healthy coronary artery or the diameter of the corresponding coronary artery in the control group in case of diffuse ectasia) is an uncommon disorder, usually associated with underlying myocardial ischemia. Micro-circulatory dysfunction has been demonstrated as one possible mechanism to explain ischemia in this disorder. Calcium antagonists have been proven to relieve microvascular spasm. Aim of the study: To test the hypothesis that relieving microvascular spasm in patients with coronary artery ectasia, through intravenous administration of verapamil, may result in improvement of microvascular coronary flow as reflected by coronary flow parameters assessed by transesophageal echocardiography (TEE). Patients and methods: Thirty patients with angiographically documented coronary artery ectasia of the left anterior descending artery were prospectively enrolled in the current study. Ten patients with normal coronary arteries were included as controls. All forty patients underwent TEE using pulsed wave Doppler (PWD) to measure peak systolic and diastolic velocities (m/sec); systolic, diastolic and total velocity time integrals (cm); and the systolic, diastolic and total coronary blood flow (cm³/min) in the proximal LAD before and after intravenous injection of verapamil (0.1 mg/kg). Results: Resting systolic, diastolic, and total coronary blood flow (cm³/min) were significantly higher in patients with ectasia compared to normal subjects (60.83 ± 27.7 cm³/min versus 25.31 ± 9.01 cm³/min, p<0.001; 126.89 ± 49.22 cm³/min versus 53.15 ± 18.30 cm³/min, p<0.001; and 188.02 ± 70.36 cm³/min versus 78.46 ± 25.97 cm³/min, p<0.001). There was a trend, not reaching statistical significance, towards higher basal peak velocities in normal subjects compared to patients with ectasia. In patients with coronary artery ectasia, intravenous injection of verapamil resulted in an increase in all observed coronary flow parameters including: peak systolic velocity (m/sec) from 0.19 ± 0.05 to 0.21 ± 0.04, p=<0.05, peak diastolic velocity (m/sec) from 0.39 ± 0.11 to 0.48 ± 0.15, p=<0.001, systolic velocity time integral (cm) from 3.0 ± 1.05 to 3.38 ± 0.78, p=<0.05, diastolic velocity time integral (cm) from 6.22 ± 1.97 to 8.42 ± 2.09, p=<0.001; total velocity time integral (cm) from 9.22 ± 2.73 to 11.8 ± 2.64, p=<0.001, systolic coronary blood flow (cm³/min) from 60.83 ± 27.7 to 69.0 ± 22.7, p=<0.05, diastolic coronary blood flow (cm³/min) from 126.89 ± 49.22 to 173.01 ± 62.4 p=<0.001, and total coronary blood flow (cm³/min) from 188.02 ± 70.36 to 242.0 ± 81.82, p=<0.001. Conclusion: Intravenous administration of verapamil resulted in statistically significant improvement of coronary flow parameters in patients with coronary artery ectasia. Further studies are needed to confirm whether continued treatment with verapamil translates to symptomatic improvement in the clinical setting.

Changes in ductus venosus flow profile in twin-twin transfusion syndrome: role in risk stratification.

To evaluate changes in ductus venosus (DV) waveforms and the timing of these changes in twin-twin transfusion syndrome (TTTS), to relate these to disease severity and to assess the clinical applicability of the suggested measurements in the prediction of TTTS. DV time intervals and velocity-time integrals (VTI) normalized to cardiac cycle and total VTI, respectively, as well as velocity ratios were analyzed in 149 monochorionic diamniotic (MCDA) twin pairs. Pregnancies were assigned to the following groups: uncomplicated MCDA (n = 29); TTTS Stages I+II (n = 50); TTTS Stages III+IV (n = 49); and pre-TTTS (n = 21), of which 14 remained stable and seven progressed to TTTS. Intertwin differences were calculated as larger/recipient minus smaller/donor and related to disease severity. Receiver-operating characteristics curve analysis was used to distinguish TTTS vs uncomplicated MCDA and pre-TTTS progressing to TTTS vs non-progressing pre-TTTS. Intra- and interobserver reliability of measurement of DV parameters were evaluated using intraclass correlation coefficients (ICCs). No intertwin differences in DV parameters were found in uncomplicated MCDA pregnancies. Diastolic VTIs and filling times were significantly shorter in recipient twins in TTTS cases and in larger pre-TTTS twins in comparison with their cotwins. Time intervals, VTIs and velocity ratios correlated significantly with Quintero stages. An intertwin difference in early filling time (eT) normalized to cardiac cycle, eT (%) ≤ -3.6%, could differentiate TTTS from uncomplicated MCDA pregnancies (82.8% sensitivity; 79.8% specificity) and eT (%) ≤ -2.8% predicted progression to TTTS (73.1% sensitivity; 67.4% specificity). DV flow profiles and timing of waveform events are already altered in pre-TTTS and early-stage disease, reflecting abnormal ventricular filling and circulatory imbalance. Intertwin comparison of filling times and VTI may allow prediction of evolving TTTS in MCDA pregnancies. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Effects of Phototherapy on Coronary Blood Flow in Healthy Neonates: A Pilot Study

Background: Phototherapy has been reported to alter blood flow to various tissues. We hypothesized that during phototherapy the coronary blood flow will decrease because of a ‘steal effect' to the periphery. Objectives: To evaluate the effects of phototherapy on coronary blood flow in healthy, jaundiced, term neonates. Methods: Flow velocity [peak diastolic velocity (Vd)] and flow measures [diastolic time velocity integral (TVId) and flow index (FI)] in the left main (LM) and left anterior descending (LAD) coronary arteries were prospectively studied with 2D/pulsed Doppler ultrasound before, during and after phototherapy in 19 healthy term, jaundiced neonates (study group) and in matched nonjaundiced controls (25 neonates). Significance was set at p < 0.05. Results: The neonates' characteristics were comparable in both groups. Sequential studies in the study group showed no significant decrease in measures of velocity and flow during phototherapy; however, there was a significant increase in some of these measures (Vd and TVId in the LM coronary artery, and Vd in the LAD coronary artery) after phototherapy. Velocity (Vd) and flow measures (TVId and FI) in the LAD coronary artery, but not in the LM coronary artery, were significantly lower when comparing the study group during phototherapy with the controls. In a multivariate model, phototherapy was an independent variable affecting Vd and TVId in LAD coronary arteries. Measures of cardiac output did not change significantly throughout the study. Conclusions: While part of our findings may suggest a modestly lower flow in coronary arteries during phototherapy, we conclude that no clinically significant alteration in coronary arterial flow occurs during phototherapy in healthy term neonates.

Superior Mesenteric Arterial Flow Pattern is Associated with Major Adverse Events in Adults with Fontan Circulation.

Factors contributing to the failure of Fontan circulation in adults are poorly understood. Reduced superior mesenteric arterial (SMA) flow has been identified in pediatric Fontan patients with protein-losing enteropathy. SMA flow has not been profiled in an adult Fontan population and its association with adverse events is unknown. We aimed to examine associations between SMA flow patterns and adverse events in adult Fontan patients. We performed a retrospective review of adult Fontan patients who underwent echocardiograms between 2008 and 2014. SMA Doppler data included peak systolic and end-diastolic velocity and velocity time integral (VTI). Systolic/diastolic (S/D) ratio and resistive index were calculated. The relationship between SMA flow parameters and major adverse events (death or transplantation) was examined using proportional hazard Cox regression analyses. Kaplan-Meyer analysis was conducted to construct survival curve of patients with and without adverse events. 91 post-Fontan adult patients (76% systemic left ventricle, 20% atriopulmonary Fontan, mean age 27.9years) were analyzed. Adverse events occurred in nine patients (death=4, transplant=5). When compared with the non-event group, the event group had increased end-diastolic velocity [hazard ratio (HR) 1.5, 95% confidence interval (CI) 1.1-1.8; p=0.002], increased systolic VTI (HR 1.5, 95% CI 1.1-2.2, p=0.02), increased diastolic VTI (HR 1.7, 95% CI 1.2-2.4, p=0.004), decreased S/D velocity ratio (HR 0.32, 95% CI 0.14-0.71, p=0.006), decreased S/D VTI ratio (HR 0.76, 95% CI 0.61-0.97, p=0.02), and decreased resistive index (HR 0.29, 95% CI 0.14-0.60, p=0.0007). Increased end-diastolic velocity and VTI in mesenteric arterial flow, with lower systolic/diastolic ratio and resistive index, were associated with death and need for heart transplant in adult Fontan patients. The mesenteric hyperemic flow was also associated with clinical signs of portal venous outflow obstruction, suggesting the presence of vasodilatory state in end-stage adult Fontan circulation.

Transcatheter Replacement of Stenotic Aortic Valve Normalizes Cardiac-Coronary Interaction by Restoration of Systolic Coronary Flow Dynamics as Assessed by Wave Intensity Analysis.

Aortic valve stenosis (AS) can cause angina despite unobstructed coronary arteries, which may be related to increased compression of the intramural microcirculation, especially at the subendocardium. We assessed coronary wave intensity and phasic flow velocity patterns to unravel changes in cardiac-coronary interaction because of transcatheter aortic valve implantation (TAVI). Intracoronary pressure and flow velocity were measured at rest and maximal hyperemia in undiseased vessels in 15 patients with AS before and after TAVI and in 12 control patients. Coronary flow reserve, systolic and diastolic velocity time integrals, and the energies of forward (aorta-originating) and backward (microcirculatory-originating) coronary waves were determined. Coronary flow reserve was 2.8±0.2 (mean±SEM) in control and 1.8±0.1 in AS (P<0.005) and was not restored by TAVI. Compared with control, the resting backward expansion wave was 45% higher in AS. The peak of the systolic forward compression wave was delayed in AS, consistent with a delayed peak aortic pressure, which was partially restored after TAVI. The energy of forward waves doubled after TAVI, whereas the backward expansion wave increased by >30%. The increase in forward compression wave with TAVI was related to an increase in systolic velocity time integral. AS or TAVI did not alter diastolic velocity time integral. Reduced coronary forward wave energy and systolic velocity time integral imply a compromised systolic flow velocity with AS that is restored after TAVI, suggesting an acute relief of excess compression in systole that likely benefits subendocardial perfusion. Vasodilation is observed to be a major determinant of backward waves.

EVALUATION OF STENOTIC LEFT main coronary ARTERY AND LEFT ANTERIOR DESCENDING CORONARY ARTERY WITH A HELP OF TRANSTHORACIC ECHOCARDIOGRAPHY

Purpose. To detect the potential of different qualitative, semi-quantitative and quantitative transthoracic Doppler signs for successful evaluation of stenotic left main coronary artery (LMCA) and left anterior descending artery (LAD). Materials and methods. 173 patients (52±10 years; 149 men) with chest pain, sinus rhythm and scheduled quantitative coronary angiography (CAG) were evaluated at rest by non-contrast transthoracic echocardiography (TT E). LMCA and proximal (p), mid (m) and distal (d) parts of the LAD were examined. The Doppler signs of coronary stenosis >50 % were determined as follows: 1 – local Doppler aliasing with the Nyquist limit set at 60 cm/s; 2 – maximal peak diastolic velocity (Vpd) >60 cm/s; 3 – ratio of stenotic/prestenotic Vpd >2.0; 4 – stenosis >50 % according to flow continuous equation: stenosis, % = 100 × (1 – prestenotic VTId / stenotic VTId), where VTId – diastolic time velocity integral. CAG was performed within 1 week after TT E. Stenosis >50 % of diameter reduction was considered as significant. Results. Sensitivity (Sens), specificity (Sp) and diagnostic accuracy (Ac) of different Doppler stenotic signs for stenotic LMCA and LAD are presented in Table 1. Thus, TT E is a method for correct evaluation of stenotic LMCA and LAD. Quantitative ratio of stenotic to prestenotic coronary flow velocities is a more sensitive sign for detecting stenosis >50 %, than qualitative and semi-quantitative evaluation of maximal coronary flow velocity only.

How arterial stiffness may affect coronary blood flow: a challenging pathophysiological link.

A relationship between arterial stiffening and coronary flow abnormalities, although not fully elucidated, has been observed. The purpose of this study was to investigate the relationship among carotid stiffness, measured using echo-tracking, and Doppler parameters of coronary blood flow, sampled at the left anterior descending (LAD) artery. We studied 88 consecutive patients (49 men, mean age 51.2 ± 16.2 years) with cardiovascular risk factors but without history of cardiovascular diseases. Each patient underwent echocardiographic evaluation for measurement of the diastolic velocity time integral (DVTI) and calculation of the diastolic velocity time integral coronary index (DVTICI), the ratio between DVTI and total velocity time integral of LAD artery flow × 100, and carotid ultrasound for measurement of carotid intima media thickness (IMT) and stiffness parameters such as β index and elastic modulus (Ep). DVTICI was significantly greater in men than in women (median 82, interquartile range 78-86 vs. median 80, interquartile range 73-83, respectively; P < 0.016). After correlating DVTICI with other variables, a significant inverse relation was obtained with β index (Rho = -0.449, P < 0.001), Ep (Rho = -0.478, P < 0.001), age (Rho = -0.52, P < 0.001), left ventricular mass index (Rho = -0.543, P < 0.001), E/E' (Rho = -0.411, P < 0.001), pulse pressure (Rho = -0.417, P < 0.001) and IMT (Rho = -0.480, P < 0.001). With linear multiple regression analysis, only β index (P < 0.001), Ep (P < 0.001), male sex (P < 0.001) and left ventricular mass index (P = 0.008) were independently associated with reduction of DVTICI. Increased arterial stiffness, directly affecting coronary perfusion, is associated with reduced diastolic coronary flow. Echo-tracking for feasible measurement of carotid artery stiffness parameters may be valuable in more accurate cardiovascular risk stratification.

Coronary Blood Flow in Patients With Severe Aortic Stenosis Before and After Transcatheter Aortic Valve Implantation

Patients with severe aortic stenosis and no obstructed coronary arteries are reported to have reduced coronary flow. Doppler evaluation of proximal coronary flow is feasible using transesophageal echocardiography. The present study aimed to assess the change in coronary flow in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI). The left main coronary artery was visualized using transesophageal echocardiography in 90 patients undergoing TAVI using the Edwards SAPIEN valve. The peak systolic and diastolic velocities of the coronary flow and the time-velocity integral were obtained before and after TAVI using pulse-wave Doppler. Mean aortic gradients decreased from 47.1 ± 15.7 mm Hg before TAVI to 3.6 ± 2.6 mm Hg after TAVI (p <0.001). The aortic valve area increased from 0.58 ± 0.17 to 1.99 ± 0.35 cm(2) (p <0.001). The cardiac output increased from 3.4 ± 1.1 to 3.8 ± 1.0 L/min (p <0.001). Left ventricular end-diastolic pressure (LVEDP) decreased from 19.8 ± 5.4 to 17.3 ± 4.1 mm Hg (p <0.001). The following coronary flow parameters increased significantly after TAVI: peak systolic velocity 24.2 ± 9.3 to 30.5 ± 14.9 cm/s (p <0.001), peak diastolic velocity 49.8 ± 16.9 to 53.7 ± 22.3 cm/s (p = 0.04), total velocity-time integral 26.7 ± 10.5 to 29.7 ± 14.1 cm (p = 0.002), and systolic velocity-time integral 6.1 ± 3.7 to 7.7 ± 5.0 cm (p = 0.001). Diastolic time-velocity integral increased from 20.6 ± 8.7 to 22.0 ± 10.1 cm (p = 0.04). Total velocity-time integral increased >10% in 43 patients (47.2%). Pearson's correlation coefficient revealed the change in LVEDP as the best correlate of change in coronary flow (R = -0.41, p = 0.003). In conclusion, TAVI resulted in a significant increase in coronary flow. The change in coronary flow was associated mostly with a decrease in LVEDP.

Left anterior descending coronary artery flow impaired by right ventricular apical pacing: The role of systolic dyssynchrony

IntroductionRight ventricular (RV) pacing may affect myocardial perfusion and coronary blood flow; however, it remains unknown whether this is related to systolic dyssynchrony induced by RV pacing. This prospective study was aimed to assess the relationship between dyssynchrony and the changes of coronary blood flow. MethodsSeventy patients with sinus node dysfunction were prospectively enrolled. Coronary flow was evaluated by measuring diastolic velocity time integral (VTI) and duration at the distal-portion of left anterior descending coronary artery (LAD) with transthoracic echocardiography at baseline and follow-up. Systolic dyssynchrony was assessed with tissue Doppler imaging by time standard deviation to peak systolic velocity of 12 left ventricular segments (Ts-SD, cutoff value ≥33ms). ResultsAdequate data for analysis was available from 65 patients. At follow-up (mean follow up time: 127±45days), LAD velocity-time integral (LAD-VTI: 12.1±4.2 vs. 10.7±4.6cm, p<0.001) was decreased and there was deterioration of left ventricular systolic function (left ventricular ejection fraction: 65±7% vs. 62±7%). However, these changes were only detected in those with RV pacing induced systolic dyssynchrony. Significant reduction of LAD-VTI (defined as ≥5%) occurred in 34 (52%) patients which was more prevalent in those with pacing-induced systolic dyssynchrony than those without (85.3% versus 16.1%, χ2=31.1, p<0.001). Though similar at baseline, LAD-VTI was significantly lower in the dyssynchrony group at follow up (p<0.001). Cox-regression analysis showed that pacing-inducing systolic dyssynchrony [hazard ratio (HR): 3.62, p=0.009] and higher accumulative pacing percentage (HR: 1.02, p=0.002) were independently associated with reduction of LAD-VTI. ROC curve demonstrated that accumulative pacing percentage ≥35% was 97% sensitive and 84% specific in revealing significant reduction (area under the curve: 0.961, p<0.001). ConclusionsRV pacing induced dyssynchrony is associated with reduced coronary flow and this may account for, in part, the deleterious effect of RV pacing on ventricular function over time.

Correlation between pulmonary regurgitation and right ventricular myocardial performance index in TOF patients after surgical repair

Objective and aimResidual PR after repair of tetralogy of Fallot is an important determinant of the outcome of patients. Patients and methodsWe aim to assess severity of PR by PR index and diastolic/systolic time velocity integrals (DSTVI) and to correlate both of them to RVMPI, to detect which is more likely to reflect RV global function. This is a cross sectional study in which 33 patients with repaired TOF, and 46 controls were enrolled. For each patient full medical history and examination were obtained, conventional and tissue Doppler echocardiography were done, to measure pulmonary regurgitation by two indices: PR index and diastolic systolic time velocity integrals (DSTVI), to measure myocardial tissue velocities at the tricuspid annulus, to determine RVMPI, and to correlate it to the PR indices. Resultsour study included 33 patients with totally corrected TOF, and 46 controls, there were statistically significant differences in S′,E′,A′ velocities, and RVMPI between cases and controls, no statistically significant correlation between PR index, DSTVI and the RVMPI of the patients. ConclusionTissue Doppler RVMPI in patients after surgical repair of Fallot tetralogy is not correlated to the degree of PR measured by two indices: PR index and DSTVI, a new index that can assess severity of PR and correlate to RV functions is required.

Functional Effect of New Atrial Septal Defect After Percutaneous Mitral Valve Repair Using the MitraClip Device

Percutaneous mitral valve repair using the MitraClip device has become a therapeutic alternative for high surgical risk patients with symptomatic mitral regurgitation. The procedure involves transseptal puncture and results in a new atrial septal defect (ASD) after withdrawal of the 22Fr guiding catheter. The functional effect of the new ASD is not defined. In 28 patients with symptomatic mitral regurgitation undergoing percutaneous mitral valve repair using the MitraClip device, 3-dimensional transesophageal echocardiography was used to measure by direct en face imaging the area of the new ASD. Analysis of the velocity-time integral (VTI) across the ASD after withdrawal of the guiding catheter allowed calculation of the shunt volume. Diastolic VTI of the mitral flow was determined before and after withdrawal of the guiding catheter to determine left ventricular inflow changes. Invasive left atrial pressure measurements were obtained during withdrawal of the guiding catheter. Regurgitant volume was reduced from 86±21 ml/beat before intervention to 43±22 ml/beat after intervention. The new ASD had an area of 0.19 cm2, 44% of the area of the 22Fr guiding catheter. Considering the VTI across the septal defect of 72±26 cm/s, the left-to-right atrial shunt volume was calculated to be 14±6 ml/beat. The diastolic forward flow across the mitral valve was reduced by 13±6 ml/beat immediately after withdrawal of the MitraClip guiding catheter. Mean left atrial pressure was reduced from 17±8 mm Hg with the guiding catheter still in the left atrium to 15±8 mm Hg after withdrawal of the guiding catheter. In conclusion, the creation of a new ASD as consequence of the large-diameter MitraClip guiding catheter results in volume and pressure relief of the left atrium. This contributes to the immediate hemodynamic changes implemented by the MitraClip procedure.