Mid-systolic Deceleration Research Articles

Unraveling the RV Ejection Doppler Envelope: Insight Into Pulmonary Artery Hemodynamics and Disease Severity

ObjectivesThe purpose of this study was to characterize the profiles of right ventricular outflow tract (RVOT) Doppler flow velocity envelopes in patients with pulmonary arterial hypertension (PAH) and to establish whether changes in the RVOT flow profile related to patient outcome. BackgroundThe RVOT systolic flow profile is frequently abnormal, with findings of a mid-systolic flow deceleration and notching, previously proposed as an indicator of elevated pulmonary vascular resistance (PVR). MethodsWe reviewed RVOT systolic flow profiles recorded by pulsed-wave Doppler from 159 consecutive patients with PAH and measured deceleration time (DT) of mid-systolic deceleration slope (mid-systolic DT) and the peak velocity of pre- and post-notching flow. Concurrent right-heart catheterization was available in all (41 of 41) incident patients and in 39 of 118 established patients. Outcomes, defined as time to all-cause mortality or need for lung transplantation, were assessed during 3 years of follow-up. ResultsNotched envelopes were identified in 150 of 159 patients. The presence of a notched pattern and a decrease in the mid-systolic DT were associated with higher PA pressures; higher PVR; and, at a threshold of a mid-systolic DT of <120 ms, worse outcome. Those patients with a shorter DT were further subdivided based on the post-notch systolic flow velocity. In these patients, a decline in the post-notch flow velocity to <62% of the pre-notch flow velocity defined a cohort with a marked reduction in systolic function and the worst outcome. ConclusionsIn PAH, the notched profile of RVOT Doppler flow velocity envelope appears to integrate indicators of pulmonary vascular load and RV function and serves as a marker for adverse outcomes.

A rare case of persistent hypoglossal artery associated with contralateral proximal subclavian stenosis.

The persistent hypoglossal artery is rare vascular anomalies. We report the case of a 50-year old man with right hypoglossal artery, ipsilateral hypoplasic internal carotid artery, associated with left proximal subclavian stenosis with subclavian steal syndrome. Power-Doppler-Ultra-Sonography spectral images obtained after the patient exercised the left arm showed mid-systolic deceleration with retrograde late-systolic velocities. A Computed Tomography Angiography demonstrated a proximal stenosis of the left SA, a mild right ICA hypoplasia and an anomalous artery arising from right ICA at C2–C3 level, entering the cranium via the hypoglossal canal and joining the basilar artery. Usually the presence of PHA may be completely asymptomatic, and detected as an incidental finding by CTA or MRA, but in our case its diagnosis is extremely important because it is often the only vessel supplying blood to the basilar trunk and posterior circulation.

Abstract 12589: Quantitative Assessment of Mid-Systolic Deceleration and Notching in the Right Ventricular Ejection Doppler Envelope is Useful in Predicting Hemodynamics and Patient Outcomes in Pulmonary Arterial Hypertension

Background: Increased reflective wave from pulmonary artery (PA) causes mid-systolic deceleration (MSD) and notching in Doppler flow velocity envelope of RV ejection flow. Our aim is to test whether profile of MSD and notching provides insight into hemodynamics and patient outcomes in pulmonary artery hypertension (PAH), using quantitative measurements. We hypothesized that the deceleration time of the MSD slope (DTMSD), meaning the steepness of the slope, reflects interaction between RV ejection and reflective wave, and that peak velocity of post-notching flow (Vpost) reflects RV function. Methods: We reviewed RV ejection flow envelope recordings by pulsed wave Doppler for 157 consecutive patients with PAH between 1/2008 and 3/2013 (age 57 ± 14) with an estimated RV systolic pressure of 79 ± 23 mmHg. DTMSD was measured as the time between the first peak acceleration wave and MSD slope extrapolated to zero line. We also reviewed right heart catheterization performed within one month from echocardiography in 78 of the 157 patients. Results: We identified MSD and notching in 148 patients. On multivariate regression analyses, PA capacitance was the key determinant of DTMSD (beta = -0.49, p &lt;0.0001). Vpost was determined by cardiac index (beta = -0.36, p = 0.0014). During a median follow-up period of 30 months, there were 47 deaths from all causes and 7 lung transplantations. On Cox hazard analyses, shorter DTMSD and smaller Vpost are significant predictors of higher mortality independently of each other (HR 0.92 / 10ms, p = 0.045 and HR 0.97, p = 0.028, respectively). Conclusion: Mid-systolic deceleration of RV ejection flow became steeper in the setting of lower PA compliance causing a greater reflectance wave. Reduced peak velocity of post-notching flow reflected impaired RV with reduced cardiac output. Quantitative assessment of profile of mid-systolic deceleration and notching in RV ejection flow envelope is useful in predicting hemodynamics and patient outcomes in PAH.

Analysis of Flow Patterns in a Patient-Specific Aortic Dissection Model

Aortic dissection is the most common acute catastrophic event affecting the thoracic aorta. The majority of patients presenting with an uncomplicated type B dissection are treated medically, but 25% of these patients develop subsequent aneurysmal dilatation of the thoracic aorta. This study aimed at gaining more detailed knowledge of the flow phenomena associated with this condition. Morphological features and flow patterns in a dissected aortic segment of a presurgery type B dissection patient were analyzed based on computed tomography images acquired from the patient. Computational simulations of blood flow in the patient-specific model were performed by employing a correlation-based transitional version of Menter's hybrid k-epsilon/k-omega shear stress transport turbulence model implemented in ANSYS CFX 11. Our results show that the dissected aorta is dominated by locally highly disturbed, and possibly turbulent, flow with strong recirculation. A significant proportion (about 80%) of the aortic flow enters the false lumen, which may further increase the dilatation of the aorta. High values of wall shear stress have been found around the tear on the true lumen wall, perhaps increasing the likelihood of expanding the tear. Turbulence intensity in the tear region reaches a maximum of 70% at midsystolic deceleration phase. Incorporating the non-Newtonian behavior of blood into the same transitional flow model has yielded a slightly lower peak wall shear stress and higher maximum turbulence intensity without causing discernible changes to the distribution patterns. Comparisons between the laminar and turbulent flow simulations show a qualitatively similar distribution of wall shear stress but a significantly higher magnitude with the transitional turbulence model.

Abdominal Aortic Doppler Waveform in Patients with Aorto-iliac Disease

Objectives The mid-systolic deceleration (notch) in the proximal descending aortic Doppler waveform was reported to be common in patients with aorto-iliac disease. However, evaluation of the descending aorta is limited to echocardiography and may be technically difficult. Therefore, we decided to check whether similar Doppler flow disturbance can be found in abdominal aorta, which is easily evaluated in wider range of patients undergoing general abdominal and vascular ultrasound, as well as echocardiography. Methods We evaluated 115 consecutive symptomatic patients with severe peripheral artery disease admitted for vascular surgery, and 60 controls. The presence or absence of the mid-systolic deceleration in the Doppler waveform was evaluated retrospectively, by the single echocardiographer blinded to the localisation of the arterial occlusion or stenosis. Results The mid-systolic notch in the proximal abdominal aorta was present in 58 of 71 patients (82%) with significant aorto-iliac disease, seven of 44 (16%) patients with occlusion or significant stenosis distally to the external iliac artery ( P < 0.001) and in none of the patients from the control group. Sensitivity, specificity and positive predictive value of the mid-systolic notch in the abdominal aortic Doppler waveform in the detection of aorto-iliac disease in patients with peripheral artery disease were 82%, 84% and 89%, respectively. Conclusion The mid-systolic deceleration (notch) in the proximal abdominal Doppler waveform is a simple ultrasonographic marker of significant aorto-iliac disease.

Descending Aortic Doppler Flow Pattern in Patients With Proximal Peripheral Artery Disease

Midsystolic deceleration (notch) in pulmonary pulse-wave (PW) Doppler flow is a common finding in patients with pulmonary embolism. The possible mechanism involves early reflection of pressure wave from proximal embolic sites. The aim of this study was to evaluate with PW Doppler whether occlusion or significant stenosis in the distal aorta or iliac arteries might produce a similar midsystolic notch in descending aortic flow. Echocardiography was performed in 97 consecutive patients with severe peripheral artery disease (PAD) admitted for vascular surgery and in 41 controls. PW Doppler assessment of flow in the proximal descending aorta was recorded from the suprasternal window. After exclusion of 13 patients due to inadequate visualization, atrial fibrillation, or aortic aneurysm, 84 patients were analyzed. Diagnosis of midsystolic notch was made by an experienced echocardiographer blinded to the vascular status of patients. A midsystolic notch in the descending aorta was present in 43 of 49 patients (87.7%) with occlusion or with >70% stenosis in the aortoiliac segment, 6 of 35 (17.1%) patients with occlusion or significant stenosis distal to the external iliac artery, and 0 patient from the control group. Sensitivity of the midsystolic notch in the detection of aortoiliac disease in patients with PAD was 87.7% and specificity was 82.8%. In conclusion, midsystolic deceleration (notch) in the descending aortic Doppler waveform is characteristic for patients with significant proximal PAD. The possible mechanism involves arterial pressure wave reflection from the occlusion or significant stenosis in the aortoiliac segment.

Innominate Artery Occlusive Disease: Sonographic Findings

The objective of this study was to report the sonographic abnormalities in a group of patients with angiographically proven innominate artery stenosis and occlusion. A review of all cerebrovascular sonograms at our institutions was undertaken to identify patients with complete or partial flow reversal in the right vertebral artery and reversal or midsystolic deceleration of flow in any one of the three major segments of the right carotid system (common, internal, or external carotid artery). The distribution and appearance of these abnormalities was evaluated, and the presence or absence of tardus-parvus waveforms was noted in any segment of the right carotid artery. Additionally, a left to right common carotid peak systolic velocity ratio (LCCA/RCCA) was calculated and compared to published normal values. All patients had correlative contrast or MR angiography. Correlation was made between the severity of stenosis as determined by angiographic images and waveform aberrations as well as the more objective LCCA/RCCA ratios. Twelve patients were identified as having the abnormalities described above in the right vertebral and carotid arteries. Doppler waveforms from the right vertebral artery revealed that eight of the 12 patients had complete reversal of flow at rest. Bidirectional flow was found in the remaining four as manifested by the presence of marked midsystolic deceleration. In the carotid arteries, one patient had complete reversal of flow in all segments of the right carotid system. Waveforms with midsystolic deceleration were identified in at least one of the carotid arteries of the remaining 11 patients: common carotid artery (8/11 = 73%), internal carotid artery (10/11 = 91%), external carotid artery (3/11 = 27%). The average LCCA/RCCA was 3.1 with a range of 1.7 to 5.7 (normal = 0.7-1.3). All patients had severe innominate artery disease (from 70% to occlusion) by contrast angiography or MR angiography. There was no correlation between the angiographically determined degree of stenosis and the Doppler findings. A distinctive pattern of hemodynamic alterations occurs in the right vertebral and carotid arteries of patients with severe innominate artery disease. Findings include reversed or bidirectional flow in the right vertebral artery, the presence of midsystolic deceleration in any of the branches of the right carotid system, and elevated LCCA/RCCA ratio.

Reflection as a cause of mid-systolic deceleration of pulmonary flow wave in dogs with acute pulmonary hypertension: comparison of pulmonary artery constriction with pulmonary embolisation

The aim was to examine whether mid-systolic deceleration of the pulmonary flow wave occurred in acute pulmonary hypertension due to pulmonary artery constriction and pulmonary embolisation, and if so whether it was related to reflection. Various degrees of pulmonary hypertension were induced by both pulmonary artery constriction and pulmonary embolisation in dogs. During control periods and during pulmonary artery constriction and pulmonary embolisation, pulmonary flow and pulmonary artery pressure were recorded, and the forward and backward (reflected) flow waves were separated from the measured pulmonary flow wave by the method of Westerhof et al. 20 adult mongrel dogs were used and 10 dogs qualified for analysis. The other 10 dogs, which died before both interventions were completed, were excluded. During pulmonary artery constriction, a distinct mid-systolic deceleration of the pulmonary flow wave was observed in five of the 10 dogs, while during pulmonary embolisation, no mid-systolic deceleration was found in these five dogs. The distinct deceleration of the pulmonary flow wave was related to a steep fall and early negative peak in the backward flow wave. Mid-systolic deceleration of pulmonary flow wave is likely to be related to reflection.