The Flow Rate in Patients With Low-Gradient Aortic Stenosis.

PURPOSE:  The decision to assess the severity and determine the ideal timing of intervention for low-gradient aortic stenosis poses a greater challenge. Recently, a novel method for determining the flow status of patients with aortic stenosis has been introduced, utilizing flow rate measurements. In this study, we investigated whether the flow status of patients with low-gradient aortic stenosis is linked to mortality within a three-year timeframe. METHODS: Twenty-nine patients diagnosed with low-gradient aortic stenosis and valve area ≤ 1 cm were identified during 2010-2015. Each patient's flow rate across the aortic valve was computed, and the study scrutinized echocardiographic parameters to ascertain their correlation with mortality over a three-year timeframe. RESULTS:  We observed that among patients with low-gradient aortic stenosis and a valve area of ≤1 cm, a decreased flow rate across the aortic valve emerged as an independent predictor of mortality. A flow rate < 210 ml/s was linked with a three-year mortality rate of 66.7%, whereas a low stroke volume index < 35 ml/m² did not show an association with three-year mortality. This observation might be attributed to the smaller body sizes prevalent among these older patients, particularly females, which could influence the calculation of the stroke volume index. CONCLUSION:  In older patients with low-gradient aortic stenosis, the flow rate can better reflect flow status than the stroke volume index, and it also suggests a prognostic significance in predicting mortality. Additional studies are warranted to validate these findings across broader patient populations and to assess the potential efficacy of early intervention strategies in this particular patient cohort.

Stroke volume index (SVI) predicts all-cause mortality following transcatheter aortic valve replacement (TAVR).

BACKGROUND: Left ventricular systolic dysfunction in patients with severe aortic stenosis (AS) may result in low transvalvular gradients and underestimation of AS severity. A low-flow state may occur with reduced LVEF. Little is known about the implications of low compared to normal flow in patients with reduced LVEF undergoing transcatheter aortic valve replacement (TAVR). OBJECTIVES: We compared survival rates with degree of flow across stenosed aortic valves and left ventricular dysfunction. We hypothesized that the stroke volume index (SVI) offers essential information regarding survival following TAVR. METHODS: We retrospectively reviewed patients with LVEF <50 % undergoing TAVR at the Gates Vascular Institute in Buffalo, New York, from 2012 to 2017. We performed Receiver Operator Characteristics to examine the value of SVI in predicting the postoperative outcome of patients. Kaplan-Meier and Cox regression analyses were used to investigate the effect of a low-flow state on five-year survival in patients with systolic dysfunction undergoing TAVR. RESULTS: Five-year survival following TAVR was decreased in patients with low-flow AS (SVI <35 mL/m2) compared to patients with normal flow. Seventy-four percent (n = 50) of patients with low-flow compared to 43 % (n = 22) of patients with normal flow were deceased five years post-TAVR (p ≤0.001). ROC curve indicated SVI to be a clinical predictor of five year survival (AUC 0.732, 95 % CI: 0.641-0.823, p < 0.001). CONCLUSION: Patients with systolic dysfunction and low transvalvular flow AS had increased mortality five years following TAVR. These findings highlight a better prognosis in patients with normal flow and LV systolic dysfunction. CONDENSED ABSTRACT: Low-flow aortic stenosis can occur with reduced left ventricular function. We compared survival rates of patients with known reduced left ventricular function in low-flow and normal flow aortic stenosis. This retrospective single-center study examined mortality rates following transcatheter aortic valve replacement. The mean gradient was not a predictor of mortality. This study shows patients with low-flow aortic stenosis have decreased five-year survival following valve replacement.

Impact of stroke volume assessment by three-dimensional transesophageal echocardiography on the classification of low-gradient aortic stenosis.

BACKGROUND: Accurate assessment of flow status is crucial in low-gradient aortic stenosis (AS). However, the clinical implication of three-dimensional transesophageal echocardiography (3DTEE) on flow status evaluation remains unclear. This study aimed to investigate the assessment of flow status using 3D TEE in low-gradient AS patients. METHODS: We retrospectively reviewed patients diagnosed with low-gradient AS and preserved ejection fraction at our institution between 2019 and 2022. Patients were categorized into low-flow/low-gradient (LF-LG) AS or normal-flow/low-gradient (NF-LG) AS based on two-dimensional transthoracic echocardiography (2DTTE). We compared the left ventricular outflow tract (LVOT) geometry between the two groups and reclassified them using stroke volume index (SVi) obtained by 3DTEE. RESULTS: Among 173 patients (105 with LF-LG AS and 68 with NF-LG AS), 54 propensity-matched pairs of patients were analyzed. 3DTEE-derived ellipticity index of LVOT was significantly higher in LF-LG AS patients compared to NF-LG AS patients (p = 0.012). We assessed the discordance in flow status classification between SVi2DTTE and SVi3DTEE in both groups using a cutoff value of 35 ml/m2. The LF-LG AS group exhibited a significantly higher discordance rate compared to the NF-LG AS group, with rates of 50% and 2%, respectively. The optimal cutoff values of SVi3DTEE for identifying low flow status, based on 2DTTE-derived cutoff values, were determined to be 43 ml/m2. CONCLUSIONS: LVOT ellipticity in low-gradient AS patients varies depending on flow status, and this difference contributes to discrepancies between SVi3DTEE and SVi2DTTE, particularly in LF-LG AS patients. Utilizing SVi3DTEE is valuable for accurately assessing flow status.

Prognostic value of transvalvular flow rate in patients with low-gradient severe aortic stenosis: A dobutamine stress echocardiography study.

BACKGROUNDS: There are limited data on the clinical relevance of transvalvular flow rate (Qmean ) at rest (Qrest) and at peak stress (Qstress ) during dobutamine stress echocardiography (DSE) in patients with low-gradient severe aortic stenosis (LG-SAS). METHODS: We retrospectively analyzed the clinical data of patients with LG-SAS who underwent DSE. LG-SAS was defined as an aortic valve (AV) area index of < .6 cm2 /m2 and a mean AV pressure gradient (AVPG) of < 40 mm Hg. The primary endpoint included all-cause death and heart failure hospitalization. RESULTS: Of 100 patients (mean age 79.5 ± 7.3 years; men, 45.0%; resting left ventricular ejection fraction [LVEF] 52.1% ± 15.9%; resting stroke volume index 35.8 ± 7.7 mL/m2 ; Qrest 171.8 ± 34.9 mL/s), the primary endpoint occurred in 51 patients during a median follow-up of 2.84 (interquartile range 1.01-5.21) years. When the study patients were divided into three subgroups based on Qrest and Qstress , the multivariate analysis showed that Qrest < 200 mL/s and Qstress ≥200 mL/s (hazard ratio 3.844; 95% confidence interval 1.143-12.930; p = .030), as well as Qrest and Qstress < 200 mL/s (hazard ratio 9.444; 95% confidence interval 2.420-36.850; p = .001), were significantly associated with unfavorable outcomes with Qrest and Qstress ≥200 mL/s as a reference after adjusting for resting LVEF, resting mean AVPG, chronic kidney disease, New York Heart Association functional class III/IV, and AV replacement. CONCLUSIONS: Flow conditions based on the combination of Qrest and Qstress are helpful for risk stratification in LG-SAS patients.

Prognostic value of flow-status in severe aortic stenosis patients undergoing percutaneous intervention.

PURPOSE: Low-flow status is a mortality predictor in severe aortic stenosis (SAS) patients, including after transcatheter aortic valve implantation (TAVI) treatment. However, the best parameter to assess flow is unknown. Recent studies suggest that transaortic flow rate (FR) is superior to currently used stroke volume index (SVi) in defining low-flow states. Therefore, we aimed to evaluate the prognostic value of FR and SVi in patients undergoing TAVI. METHODS: A single-centre retrospective analysis of all consecutive patients treated with TAVI for SAS between 2011 and 2019 was conducted. Low-FR was defined as < 200 mL/s and low-SVi as < 35 mL/m2. Primary endpoint was all-cause five-year mortality, analyzed using Kaplan-Meier curves and Cox regression models. Secondary endpoint was variation of NYHA functional class six months after procedure. Patients were further stratified according to ejection fraction (EF < 50%). RESULTS: Of 489 cases, 59.5% were low-FR, and 43.1% low-SVi. Low-flow patients had superior surgical risk, worse renal function, and had a higher prevalence of coronary artery disease. Low-FR was associated with mortality (hazard ratio 1.36, p = 0.041), but not after adjustment to EuroSCORE II. Normal-SVi was not associated with survival, despite a significative p-trend for its continuous value. No associations were found for flow-status and NYHA recovery. When stratifying according to preserved and reduced EF, both FR and SVi did not predict all-cause mortality. CONCLUSION: In patients with SAS undergoing TAVI, a low-FR state was associated with higher mortality, as well as SVi, but not at a 35 mL/m2 cut off.

Comparative evaluation of stroke volume variation measured by pulse wave transit time and arterial pressure wave.

BACKGROUND: Several monitors have been developed that measure stroke volume (SV) in a beat-to-beat manner. Accordingly, Stroke volume variation (SVV) induced by positive pressure ventilation is widely used to predict fluid responsiveness. OBJECTIVE: The purpose of this study was to compare the ability of two different methods to predict fluid responsiveness using SVV, stroke volume variation by esCCO (esSVV) and stroke volume variation by FloTrac/VigileoTM (flSVV). METHODS: esSVV, flSVV, and stroke volume index (SVI) by both monitoring devices of 37 adult patients who underwent laparotomy surgery, were measured. Receiver operating characteristic (ROC) analysis was performed. RESULTS: The area under the ROC curve (AUC) of esSVV was significantly higher than that of flSVV (p= 0.030). esSVV and flSVV showed cutoff values of 6.1% and 10% respectively, to predict an increase of more than 10% in SVI after fluid challenge. The Youden index for esSVV was higher than flSVV, even with a cutoff value between 6% and 8%. CONCLUSION: Since esSVV and flSVV showed significant differences in AUC and cutoff values, the two systems were not comparable in predicting fluid responsiveness. Furthermore, it seems that SVV needs to be personalized to accurately predict fluid responsiveness for each patient.

Worsening Symptoms Is Associated with Larger Cerebral Blood Flow Abnormalities during Tilt-Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Background and Objectives: During tilt testing, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients experience an abnormal reduction in cerebral blood flow (CBF). The relationship between this CBF reduction and symptom severity has not been examined in detail. Our hypothesis was that ME/CFS severity is related to the degree of the CBF reduction during tilt testing. Materials and Methods: First, from our database, we selected ME/CFS patients who had undergone assessments of ME/CFS symptomatology and tilt tests on the same day, one at the first visit and the second during a follow-up. The change in symptomatology was related to the change in CBF during the tilt test. Second, we combined the data of two previously published studies (n = 219), where disease severity as defined by the 2011 international consensus criteria (ICC) was available but not published. Results: 71 patients were retested because of worsening symptoms. The ICC disease severity distribution (mild-moderate-severe) changed from 51/45/4% at visit-1 to 1/72/27% at follow-up (p < 0.0001). The %CBF reduction changed from initially 19% to 31% at follow-up (p < 0.0001). Of 39 patients with stable disease, the severity distribution was similar at visit-1 (36/51/13%) and at follow-up (33/49/18%), p = ns. The %CBF reduction remained unchanged: both 24%, p = ns. The combined data of the two previously published studies showed that patients with mild, moderate, and severe disease had %CBF reductions of 25, 29, and 33%, respectively (p < 0.0001). Conclusions: Disease severity and %CBF reduction during tilt testing are highly associated in ME/CFS: a more severe disease is related to a larger %CBF reduction. The data suggest a causal relationship where a larger CBF reduction leads to worsening symptoms.

Effect of the Duration of Restrictive Fluid Therapy on Acute Kidney Injury in Robot-Assisted Laparoscopic Prostatectomy.

BACKGROUND: In robot-assisted laparoscopic prostatectomy (RALP), restrictive fluid therapy (RFT) is often utilized until the vesicourethral anastomosis (console period) is completed. RFT can cause acute kidney injury (AKI). Thus, RFT prolongation in surgeries that utilize the Trendelenburg position and pneumoperitoneum may increase the risk of postoperative AKI. We aimed to evaluate the effect of RFT duration on postoperative AKI. METHODS: Forty-four patients who underwent RALP were included in this prospective observational study. Patients were divided into two groups according to the RFT duration (Group I, RFT duration ≤ 3 h, and Group II, RFT duration >3 h). AKI was diagnosed and staged according to the Kidney Disease Improving Global Outcomes criteria (KDIGO) using patients' serum creatinine levels after the first 24 h postoperatively. Hemodynamic parameters were monitored using the pressure recording analytical method. RESULTS: The AKI incidence was significantly higher in Group II than in Group I (45.5% vs. 9.1%; p = 0.016). In both groups, all patients who developed AKI were KDIGO stage 1 and all recovered on the second postoperative day. At the end of the console period, the heart rate and arterial elastance were significantly higher, whereas the stroke volume index was significantly lower in Group II than in Group I (p = 0.041, p = 0.016, and p < 0.001, respectively). Although the amounts of fluid administered before and after the anastomosis were similar between the groups, the total amount of fluid administered was significantly different (p < 0.001). There was a significant negative correlation between RFT duration and the total amount of fluid administered (r2 = 0.43, p < 0.001). RFT duration of >3 h, total fluid administration of ≤3.3 mL/kg/h, and stroke volume index (SVI) at the end of the console period of ≤32 mL/m2 increased the risk of AKI by 12.0 times (1.7-85.2) (p = 0.013). CONCLUSION: RFT prolongation in RALP may increase the risk of developing AKI.

Low Transvalvular Flow Rate in Patients Undergoing Transcatheter Aortic Valve Implantation (TAVI) Is a Predictor of Mortality: The TFR-TAVI Study.

BACKGROUND: Transvalvular flow rate (TFR) represents a better reflection of transvalvular flow than the stroke volume index (SVi), and has recently emerged as a useful prognostic tool in patients undergoing surgical aortic valve replacement. There is a paucity of data investigating the role of TFR and its relationship with other clinical or echocardiographic factors in patients undergoing transcatheter aortic valve implantation (TAVI). METHOD: This was a retrospective single-centre study of 629 consecutive patients who underwent TAVI between March 2009 and September 2020. Pre-TAVI low TFR was defined as <200 c/s. The primary study end point was all-cause mortality. RESULTS: Low TFR was observed in 41.8% (263/629) of included patients and was associated with increasing age, low body surface area, hypertension, diabetes, atrial fibrillation, left ventricular (LV) dysfunction, and significant mitral regurgitation. LV function status and severity of aortic valve disease were independent predictors of low TFR. Low TFR was significantly associated with long-term all-cause mortality even after adjustment for other risk factors (adjusted hazard ratio [aHR] 1.44; 95% confidence interval [CI] 1.02-2.03; p=0.038). When data were stratified according to SVi, low TFR was an independent predictor of long-term all-cause mortality in patients with normal SVi (aHR 1.98; 95% CI 1.06-3.69; p=0.032) but not in patients with low SVi (HR 1.23; 95% CI 0.71-2.11; p=0.46; p=0.016 for interaction). CONCLUSIONS: Low TFR is common in patients undergoing TAVI and is an independent predictor of all-cause mortality, particularly in patients with normal SVi.

Outcome of Patients With Both Moderate Aortic Stenosis and Moderate Mitral Stenosis.

Aims: This study aimed to investigate the symptoms and prognosis of patients with both moderate aortic stenosis (AS) and mitral stenosis (MS). Methods and Results: We studied 82 patients with moderate AS and MS diagnosed via transthoracic echocardiography. The patients had a mean age of 79 ± 13 years and 95% of patients had degenerative MS. Out of 82 patients, 34 (41%) had heart failure (HF) symptoms (New York Heart Association class ≥ Ⅱ) or a history of HF admission. Left ventricular ejection fraction, stroke volume index, atrial fibrillation, and right ventricular systolic pressure were independent determinants of HF symptoms. The median follow-up duration was 3.2 (interquartile range, 1.0-4.9) years and clinical events occurred in 48 (59%) patients, including death in 11 (13%) patients, aortic or mitral valve interventions in 22 (27%) patients, and HF hospitalization in 15 (18%) patients. The 5-year survival free of the combined endpoint of aortic or mitral valve interventions, HF hospitalization, or death was 19%. A multivariate predictor of clinical events was HF symptoms (hazard ratio [HR], 2.32; 95% confidence interval [CI], 1.30-4.14; p = 0.0045). Kaplan-Meier survival at 5 years was 61% without intervention and HF symptoms were not associated with mortality. Conclusions: Among patients with both moderate AS and MS, left ventricular ejection fraction, stroke volume index, atrial fibrillation, and right ventricular systolic pressure were strong determinants of HF symptoms. HF symptoms were independently predictive of clinical events.

Hypotension after Anesthesia Induction: Target-Controlled Infusion Versus Manual Anesthesia Induction of Propofol.

BACKGROUND: Post-induction hypotension frequently occurs and can lead to adverse outcomes. As target-controlled infusion (TCI) obviates the need to calculate the infusion rate manually and helps safer dosing with prompt titration of the drug using complex pharmacokinetic models, the use of TCI may provide a better hemodynamic profile during anesthesia induction. This study aimed to compare TCI versus manual induction and to determine the hemodynamic risk factors for post-induction hypotension. METHODS: A total of 200 ASA grade 1-3 patients, aged 24 to 82 years, were recruited and randomly assigned to the TCI (n = 100) or manual induction groups (n = 100). Hemodynamic parameters were monitored with the pressure-recording analytic method. The propofol dosage was adjusted to keep the Bispectral Index between 40 and 60. RESULTS: Post-induction hypotension was significantly higher in the manual induction group than in the TCI group (34% vs. 13%; p < 0.001, respectively). The propofol induction dose did not differ between the groups (TCI: 155 (135-180) mg; manual: 150 (120-200) mg; p = 0.719), but the induction time was significantly longer in the TCI group (47 (35-60) s vs. 150 (105-220) s; p < 0.001, respectively). In the multivariable Cox regression model, the presence of hypertension, stroke volume index (SVI), cardiac power output (CPO), and anesthesia induction method were found to predict post-induction hypotension (p = 0.032, p = 0.013, p = 0.024, and p = 0.015, respectively). CONCLUSION: TCI induction with propofol provided better hemodynamic stability than manual induction, and the presence of hypertension, a decrease in the pre-induction SVI, and the CPO could predict post-induction hypotension.

Orthostatic chronotropic incompetence in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Background: Orthostatic intolerance (OI) is a core diagnostic criterion in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The majority of ME/CFS patients have no evidence of hypotension or postural orthostatic tachycardia syndrome (POTS) during head-up tilt, but do show a significantly larger reduction in stroke volume index (SVI) when upright compared to controls. Theoretically a reduction in SVI should be accompanied by a compensatory increase in heart rate (HR). When there is an incomplete compensatory increase in HR, this is considered chronotropic incompetence. This study explored the relationship between HR and SVI to determine whether chronotropic incompetence was present during tilt testing in ME/CFS patients. Methods: From a database of individuals who had undergone tilt testing with Doppler measurements for SVI both supine and end-tilt, we selected ME/CFS patients and healthy controls (HC) who had no evidence of POTS or hypotension during the test. To determine the relation between the HR increase and SVI decrease during the tilt test in patients, we calculated the 95% prediction intervals of this relation in HC. Chronotropic incompetence in patients was defined as a HR increase below the lower limit of the 95th % prediction interval of the HR increase in HC. Results: We compared 362 ME/CFS patients with 52 HC. At end-tilt, tilt lasting for 15 (4) min, ME/CFS patients had a significantly lower SVI (22 (4) vs. 27 (4) ml/m2; p < 0.0001) and a higher HR (87 (11) vs. 78 (15) bpm; p < 0.0001) compared to HC. There was a similar relationship between HR and SVI between ME/CFS patients and HC in the supine position. During tilt ME/CFS patients had a lower HR for a given SVI; 37% had an inadequate HR increase. Chronotropic incompetence was more common in more severely affected ME/CFS patients. Conclusion: These novel findings represent the first description of orthostatic chronotropic incompetence during tilt testing in ME/CFS patients.

The prognostic significance of stroke volume index in low gradient severe aortic stenosis: from the national echo database of Australia.

Approximately 50% of patients with severe aortic stenosis (AS) in clinical practice present with 'low-gradient' haemodynamics. Stroke Volume Index (SVI) is a measure of left ventricular output, with 'normal-flow' considered as > 35 ml/m2. The association between SVI and prognosis in severe low-gradient AS (LGAS) in currently not well-understood. We analysed the National Echo Database of Australia (NEDA) and identified 109,990 patients with sufficiently comprehensive echocardiographic data, linked to survival information. We identified 1,699 with severe LGAS and preserved ejection fraction (EF) (≥ 50%) and 774 with severe LGAS and reduced EF. One- and three-year survival in each subgroup were assessed (follow-up of 74 ± 43 months), according to SVI thresholds. In patients with preserved EF the mortality "threshold" was at SVI < 30 ml/m2; 1- and 3-year survival was worse for those with SVI < 30 ml/m2 relative to those with SVI > 35 ml/m2 (HR 1.80, 95% CI 1.32-2.47 and HR 1.38, 95% CI 1.12-1.70), while survival was similar between those with SVI 30-35 ml/m2 and SVI > 35 ml/m2. In patients with reduced EF the mortality "threshold" was 35 ml/m2; 1- and 3-year survival was worse for both those with SVI < 30 ml/m2 and 30-35 ml/m2 relative to those with SVI > 35 ml/m2 (HR 1.98, 95% CI 1.27-3.09 and HR 1.41, 95% CI 1.05-1.93 for SVI < 30 ml/m2 and HR 2.02, 95% CI 1.23-3.31 and HR 1.56, 95% CI 1.10-2.21 for SVI 30-35 ml/m2). The SVI prognostic threshold for medium-term mortality in severe LGAS patients is different for those with preserved LVEF (< 30 ml/m2) compared to those with reduced LVEF (< 35 ml/m2).

Stroke volume index and transvalvular flow rate trajectories in severe aortic stenosis treated with TAVR.

AIMS: The prognostic impact of flow trajectories according to stroke volume index (SVi) and transvalvular flow rate (FR) in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) remains poorly assessed. We evaluated and compared SVi and FR prior and after TAVR for severe AS. METHODS AND RESULTS: Patients were categorized according to SVi (<35 mL/m2) and FR (<200 mL/s). The association of pre- and post-TAVR SVi and FR with all-cause mortality up to 3 years was assessed with multivariable Cox regression models. Among 980 patients with pre-TAVR flow assessment, SVi was reduced in 41.3% and FR in 48.1%. Baseline flow status was not an independent mortality predictor [SVi: hazard ratio (HR) 1.22, 95% confidence interval (CI) 0.85-1.82, FR: HR 0.78, 95% CI 0.48-1.27]. Among 731 patients undergoing early (5 days, interquartile range 2-29) post-TAVR flow assessment, SVi recovered in 40.1% and FR in 49.0% patients with baseline low flow. Reduced FR following TAVR was an independent predictor of mortality (HR 1.67, 95% CI 1.02-2.74), whereas SVi was not (HR 0.97, 95% CI 0.53-1.78). Three-year estimated mortality in patients with recovered FR was lower than that in patients with reduced FR (13.3 vs. 37.7% vs, P = 0.003) and similar to that in patients with normal baseline FR (P = 0.317). CONCLUSION: Baseline flow status was not an independent predictor of mid-term mortality among all-comers with severe AS undergoing TAVR. Flow recovery early after TAVR was frequent. Post-TAVR FR, but not SVi, was independently associated with mid-term all-cause mortality. By impacting flow status, AV replacement modifies the association of flow status with outcomes.

Assessing maternal cardiac function by obstetricians: technique and reference ranges.

BACKGROUND: A strong body of evidence has now coalesced indicating that some obstetrical syndromes may result from maladaptive responses of the maternal cardiovascular system. Longitudinal studies have shown that these changes are complex and present before the clinical recognition of preeclampsia and fetal growth restriction, suggesting that hemodynamic maladaptation may play an etiologic role in obstetrical complications. Chronic hypertension is one of the most frequent complications of pregnancy, and recent evidence suggests that control of mild hypertension in early pregnancy improves outcome. The management of chronic hypertension can be improved by understanding specific cardiovascular hemodynamic abnormalities such as increased cardiac output or increased systemic vascular resistance, which can respond to either beta or calcium channel blockers, depending on the hemodynamic findings. Evaluation of maternal cardiac function has not been previously available to obstetrical healthcare providers using diagnostic ultrasound equipment used for fetal evaluation. OBJECTIVE: Obstetrical ultrasound machines may be configured for various probes (endovaginal, abdominal, 3D/4D, and cardiac). This study used a cardiac probe placed in the suprasternal notch to image and measure the descending aorta diameter and the velocity time integral using pulsed and continuous wave Doppler ultrasound in normal pregnant women between 11 and 39 weeks of gestation. These measurements were followed by computation of maternal left ventricular preload, afterload, contractility, and blood flow. STUDY DESIGN: This was a prospective cross-sectional study. A total of 400 pregnant women were recruited between 11 and 39 weeks of gestation. Imaging of the maternal aortic arch was performed by placing a cardiac probe in the suprasternal notch to identify the aortic arch using 2D and color Doppler ultrasound. The end-systolic diameter of the aorta was measured at the junction of the left subclavian artery with the descending aorta, which was followed by insonation of the descending aorta to obtain the Doppler waveform. Following insonation of the descending aorta, measurements of the aortic diameter, velocity time integral, ejection time, mean pressure gradient, heart rate, maternal weight and height, and systolic and diastolic blood pressures were entered into an Excel spreadsheet to compute the following: (1) preload measurements of stroke volume, stroke volume index, and stroke work index; (2) afterload measurements of systemic vascular resistance and the potential-to-kinetic energy ratio; (3) contractility measurements of inotropy and the Smith-Madigan inotropy index; and (4) blood flow measurements of cardiac output and the cardiac output index. Fractional polynomial regression analysis was performed for each of the above measurements using gestational age as the independent variable. RESULTS: The diastolic and mean arterial blood pressure decreased from 11 to 18 weeks of gestation and then increased until term. The afterload measurements demonstrated similar characteristics, as all values decreased from 11 weeks until the mid and late second trimester, after which all values increased until term. Changes in contractility demonstrated an increase from 11 weeks to 25 to 28 weeks, followed by a decline until term. Changes in blood flow demonstrated an increase from 11 to 27 weeks and then declined until term. The continuous wave Doppler values were greater than the pulsed Doppler values except for the contractility measurements. Examples of abnormal cardiac measurements were identified in pregnant patients with hypertension and fetal growth restriction. An Excel calculator was created to provide quick computation of z-score measurements and their corresponding centiles described in this study. CONCLUSION: The technique for evaluation of maternal cardiac function described in this study would allow screening of maternal left ventricular preload, afterload, contractility, and blood flow in the obstetrical clinical milieu once a cardiac probe is acquired for obstetrical ultrasound machines used for fetal evaluation. The above measurements would allow the clinician to select appropriate hypertensive medication on the basis of the results of the evaluation of the maternal left ventricle.

Left ventricular stroke volume index following transcatheter aortic valve replacement is an early predictor of 1-year survival.

BACKGROUND: Adverse cardiac events are common following transcatheter aortic valve replacement (TAVR). Our aim was to investigate the low left ventricular stroke volume index (LVSVI) 30 days after TAVR as an early echocardiographic marker of survival. HYPOTHESIS: Steady-state (30-day) LVSVI after TAVR is associated with 1-year mortality. METHODS: A single-center retrospective analysis of all patients undergoing TAVR from 2017 to 2019. Baseline and 30-day post-TAVR echocardiographic LVSVI were calculated. Patients were stratified by pre-TAVR transaortic gradient, surgical risk, and change in transvalvular flow following TAVR. RESULTS: This analysis focuses on 238 patients treated with TAVR. The 1-year mortality rate was 9% and 124 (52%) patients had normal flow post-TAVR. Of those with pre-TAVR low flow, 67% of patients did not normalize LVSVI at 30 days. The 30-day normal flow was associated with lower 1-year mortality when compared to low flow (4% vs. 14%, p = .007). This association remained significant after adjusting for known predictors of risk (adjusted odds ratio [OR] of 3.45, 95% confidence interval: 1.02-11.63 [per 1 ml/m2 decrease], p = .046). Normalized transvalvular flow following TAVR was associated with reduced mortality (8%) when compared to those with persistent (15%) or new-onset low flow (12%) (p = .01). CONCLUSIONS: LVSVI at 30 days following TAVR is an early echocardiographic predictor of 1-year mortality and identifies patients with worse intermediate outcomes. More work is needed to understand if this short-term imaging marker might represent a novel therapeutic target.

Correlation of carotid Doppler flowmetry with fluid responsiveness in mechanically ventilated patients undergoing coronary artery bypass grafting-A popular gray zone.

The authors conducted a prospective, observational study to evaluate the correlation of fluid responsiveness with commonly used carotid Doppler-derived indices like carotid artery blood flow, carotid corrected flow time, respirophasic variation in carotid artery blood flow peak velocity in patients undergoing coronary artery bypass grafting. They claimed that altough only ΔVpeak demonstrated some predictive power with areas under receiver operating characteristic of 0.671, carotid Doppler ultrasound indices were found to be not dependable as a substitute for invasive methods to assess fluid responsiveness. The presence of studies advocating quite different sentiments in the literature regarding feasibility and reliability show that there is a long way gone and a long way to go.

Reliability of bioreactance-derived hemodynamic monitoring during simulated sustained gravitational transitions induced by short-arm human centrifugation.

Precise, sensitive, and non-invasive estimates of stroke volume index (SVI) would facilitate clinical decision making and tracking of cardiorespiratory fitness in space. Thoracic electrical bioreactance (TEBR) is capable of providing valid SVI estimates on Earth; however, its reliability in response to simulated sustained gravitational transitions is unknown. Ten healthy male subjects underwent short-arm human centrifugation (SAHC) equivalent to 1 g and 1.5 g at their center of mass along the z-axis (gz) for 10 min each (first 5 min: passive; last 5 min: active, leg press movements), interspersed by periods without centrifugation (µg). The TEBR-based device Starling™ SV was used to estimate SVI during the five distinct passive gz phases. Precision of SVI measurements and sensitivity to hemodynamic changes induced by simulated gz transitions were determined. Overall SVI precision was very high (coefficient of variation = 3.6%), whereas mean sensitivity to SVI changes was satisfactory (sensitivity index = 75%). This study shows that the TEBR-based device Starling™ SV is precise and sensitive to hemodynamic changes in response to simulated sustained gz transitions induced by SAHC. Thus, it may be a suitable non-invasive hemodynamic monitor during human spaceflight. Further evaluation of Starling™ SV against a reference method in simulated microgravity is warranted.

Echocardiographic Investigation of Low-Flow State in a Hispanic/Latino Population.

Objective: To assess the prevalence of low-flow state (LFS) with left ventricular (LV) stroke volume index of less than 35 mL/m2 and the demographics, clinical and echocardiographic characteristics associated with LV remodeling and function in a Hispanic/Latino population. Participants and Methods: The study included 1346 asymptomatic participants from the Hispanic Community Health Study/Study of Latinos with normal LV ejection fraction (≥55%) and no valvular heart disease. LV volume, mass and left atrial volume, LV ejection fraction, global longitudinal strain, and myocardial contraction fraction were measured by echocardiography. The participants were divided into LFS or normal flow state (NFS: stroke volume index ≥35 mL/m2). Demographics, clinical and echocardiographic characteristics, and measures of LV remodeling and function were compared between the LFS and NFS groups. Results: The prevalence of LFS was 41%. In comparison with NFS, the LFS had lower LV mass index (77.2±0.96 g/m2 vs 84.6±0.86 g/m2; P<.001), left atrial volume index (20.6±0.35 mL/m2 vs 23.5±0.37 mL/m2; P<.001), global longitudinal strain (-16.8±0.16% vs -17.7±0.17%; P<.001), and myocardial contraction fraction (43.3±0.63% vs 55.7±0.64%; P<.001). There was no significant difference in the relative wall thickness (LFS: 0.40±0.004 vs NFS: 0.40±0.005; P=.57). The LFS group had significantly higher hemoglobin A1c (6.18±0.07% vs 5.97±0.04%; P=.01) than the NFS group. Conclusion: A high prevalence of LFS associated with echocardiographic characteristics reflecting unfavorable LV remodeling and function was observed in a Hispanic/Latino population. Further studies of the prognostic significance of LFS in a large multiethnic population are warranted.

Hemodynamic reserve predicts early right heart failure after LVAD implantation.

BACKGROUND: Early right heart failure (RHF) remains a major source of morbidity and mortality after left ventricular assist device (LVAD) implantation, yet efforts to predict early RHF have proven only modestly successful. Pharmacologic unloading of the left ventricle may be a risk stratification approach allowing for assessment of right ventricular and hemodynamic reserve. METHODS: We performed a multicenter, retrospective analysis of patients who had undergone continuous-flow LVAD implantation from October 2011 to April 2020. Only those who underwent vasodilator testing with nitroprusside during their preimplant right heart catheterization were included (n = 70). Multivariable logistic regression was used to determine independent predictors of early RHF as defined by Mechanical Circulatory Support-Academic Research Consortium. RESULTS: Twenty-seven patients experienced post-LVAD early RHF (39%). Baseline clinical characteristics were similar between patients with and without RHF. Patients without RHF, however, achieved higher peak stroke volume index (SVI) (30.1 ± 8.8 vs 21.7 ± 7.4 mL/m2; p < 0.001; AUC: 0.78; optimal cut-point: 22.1 mL/m2) during nitroprusside administration. Multivariable analysis revealed that peak SVI was significantly associated with early RHF, demonstrating a 16% increase in risk of early RHF per 1 ml/m2 decrease in SVI. A follow up cohort of 10 consecutive patients from July 2020 to October 2021 resulted in all patients being categorized appropriately in regards to early RHF versus no RHF according to peak SVI. CONCLUSION: Peak SVI with nitroprusside administration was independently associated with post-LVAD early RHF while resting hemodynamics were not. Vasodilator testing may prove to be a strong risk stratification tool when assessing LVAD candidacy though additional prospective validation is needed.