Revisiting the relationship between left ventricular ejection fraction and ventricular-arterial coupling

Aerobic Training Attenuates Differences Between Black and White Adults in Left Ventricular-Vascular Coupling and Wasted Pressure Effort

BACKGROUND

Black compared with White adults have a higher risk for left-ventricular hypertrophy and heart failure possibly due to the early onset of alterations in ventricular-vascular coupling (ie, arterial [Ea] to ventricular elastance [Ees] ratio) and wasted pressure effort (Ew). Aerobic training preserves the coupling ratio (Ea/Ees) and attenuates Ew, but whether this applies to Black adults is unknown. We hypothesized that Black rather than White adults would have greater training-induced improvements in the Ea/Ees and Ew.

METHODS AND RESULTS

Fifty-four young adults with normal blood pressure (Black=24 [58% female]; White=30 [47% female], mean=24 years; SD=5 years) completed an 8-week aerobic training (3 times/week, 65%-85% peak oxygen uptake). Ea/Ees was estimated via echocardiography and scaled to body surface area, and the Ew was estimated from pulse contour analysis. Black adults had lower Ea/Ees (difference (d)=0.49 [95% CI, 0.14-0.84 mm Hg/mL], P=0.007) and higher Ew (d=1127 [95% CI, 104-2007 dyne cm-2 s], P=0.005). Both groups exhibited similar (race-by-training interaction, P=0.986) training-induced reductions in scaled Ea (d=-0.11 [95% CI, -0.18 to -0.04 mm Hg/mL], P<0.001). Only in White adults, scaled Ees increased (dwhite=0.39 [95% CI, 0.11-0.32 mm Hg/mL], P=0.003) and Ea/Ees was reduced (dwhite=-0.16 [95% CI, -0.33 to -0.18 mm Hg/mL/m2], P<0.001). Conversely, only Black adults exhibited reductions in Ew after training (dblack=-699 [95% CI, -1209 to -189 dyne cm-2 s], P=0.008).

CONCLUSIONS

Aerobic training-induced differential effects on Ea/Ees and Ew of White and Black young adults hold the potential to reduce racial disparities. This warrants confirmation in a larger sample.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01024634.

BILL Strategy: Points to Consider During the Performance and Interpretation of Critical Care Echocardiography

The growing utilization of critical care echocardiography (CCE) by clinicians necessitates a meticulous review of clinical conditions in critically ill patients, both before and during the examination. The reviewing process of clinical conditions minimizes the risk of overlooking or misinterpreting crucial findings. This article proposes a comprehensive strategy, namely BILL strategy, to integrate into the CCE protocol, where "B" represents baseline respiratory and hemodynamic support, "I" signifies information gleaned from invasive monitoring, including central venous pressure and thermodilution-derived cardiac output, the first "L" denotes laboratory results such as central venous oxygen saturation, troponin, and brain natriuretic peptide, and the second "L" refers to lung ultrasound data. Combining the BILL strategy with CCE can enhance comprehensive understanding of critical conditions, potentially leading to improved diagnostic accuracy and patient outcomes.

Echocardiographic Predictors of Readiness for Double Switch Operation and Postoperative Ejection Fraction in Patients With Congenitally Corrected Transposition of the Great Arteries Undergoing Left Ventricular Retraining

BACKGROUND

In patients with congenitally corrected transposition of the great arteries (ccTGA), assessment of readiness for the double switch operation (DSO) after pulmonary arterial band (PAB) placement involves cardiac magnetic resonance imaging (cMRI) to measure left ventricular ejection fraction (LVEF) and mass and cardiac catheterization (catheterization) to assess the ratio of left ventricular to right ventricular pressure (LV:RVp). The aims of this study were to describe the relationships between echocardiographic and catheterization and cMRI measures of readiness for DSO and to develop risk factors for left ventricular (LV) dysfunction after DSO on the basis of echocardiographic measures of ventricular-arterial coupling (VAC).

METHODS

Patients with ccTGA undergoing LV retraining at a DSO referral center were reviewed. LVEF measured by echocardiography was compared with that measured by cMRI, and LV:RVp measured by echocardiography was compared with that measured by catheterization using Bland-Altman analysis. The relationship between preoperative VAC markers and postoperative echocardiography was analyzed using ventricular end-systolic elastance (EES) and a novel marker consisting of the product of LVEF and LV:RVp (EFPR).

RESULTS

Thirty-one patients with 56 evaluations for DSO were included, 24 of whom underwent DSO. Echocardiographic LVEF correlated well with cMRI LVEF (r = 0.79), and Bland-Altman analysis slightly overestimated cMRI LVEF (mean difference, +3%). Echocardiographic LVEF had a moderate ability to identify normal cMRI LVEF (area under the curve, 0.80) and at an optimal cut point of echocardiographic LVEF threshold of 61%, there was 71% sensitivity and 76% specificity to detect cMRI LVEF ≥ 55%. Echocardiographic LV:RVp correlated well with LV/RVp by catheterization (r = 0.77) and slightly underestimated the catheterization value (mean difference, -0.11). Echocardiographic LV:RVp had a good ability to identify adequate LV:RVp by catheterization (area under the curve, 0.95) and at an optimal echocardiography cut point of 0.75 had 100% sensitivity and 85% specificity to detect a catheterization LV:RVp >0.9. Echocardiography-based criteria for DSO readiness (echocardiographic LVEF of 61% and LV:RVp of 0.75) demonstrated specificity of 97% and positive predictive value of 96% for published criteria of DSO readiness (cMRI LVEF of 55% and catheterization LV:RVp of 0.9). EES and EFPR correlated with post-DSO LVEF (ρ = 0.72 and ρ = 0.60, respectively). EFPR of 0.51 demonstrated 78% sensitivity and 100% specificity for post-DSO LV dysfunction (LVEF < 55%). Age at first PAB also strongly correlated with post-DSO LVEF (ρ = 0.75). No patient with first PAB at <1 year of age exhibited post-DSO LV dysfunction.

CONCLUSIONS

Echocardiographic measures of LVEF and LV:RVp are reliable indicators of reference standard modalities and can guide management during retraining. The preoperative VAC markers EES and EFPR may be useful markers of post-DSO LV dysfunction. Values of echocardiographic LV:RVp >0.75 are likely to meet pressure-generation criteria for DSO and should be considered for referral to catheterization and cMRI evaluation for DSO. PAB placement before 1 year of life may optimize LV outcomes in patients considered for DSO.

U-shaped prognostic value of left ventricular-arterial coupling in septic patients: a prospective study

BACKGROUND

Ventricular-arterial coupling (VAC) has garnered increasing interest in critical care. The prognostic significance of left ventricular-arterial coupling (LVAC) in this context remains a topic of debate.

OBJECTIVE

This study aimed to explore the association between LVAC and patient outcomes in sepsis.

METHODS

Patients with sepsis or septic shock admitted to the intensive care unit (ICU) were included. LVAC was evaluated using the arterial elastance (Ea)/left ventricular end-systolic elastance (Ees) ratio. Prognostic indicators, including 30-day mortality, length of ICU stay, mechanical ventilation (MV), changes in delta lactate levels, and oxygen index were also collected.

RESULTS

A total of 388 patients were enrolled in this study. A U-shaped relationship was observed between LVAC and 30-day mortality, with an optimal LVAC value of 1.19 identified. For LVAC values above 1.19, the odds ratio (OR) for 30-day mortality was 1.07 (95% confidence interval [CI] 1.01-1.14). Below this threshold, OR was 0.85 (95% CI 0.73, 0.99). Similarly, in the curve for ICU-free days, a β value of - 8.64 (95% CI - 16.53, - 0.76) was noted for LVAC values over 1.26. For ventilator-free time, the kink point was 1.24, with significant β values on both sides of this threshold [- 226.49 (95% CI - 411.59, - 41.38) and 147.67 (95% CI 12.40, 282.93), respectively].

CONCLUSIONS

This study established U-shaped associations between LVAC and various clinical outcomes in septic patients. Optimizing LVAC could potentially enhance patient prognosis. Given the slight variations in optimal LVAC values across different patient populations, individualized LVAC titration may be beneficial in improving clinical outcomes.

Ventriculo-arterial (VA) coupling and fQRS as new selection criteria for primary prevention ICD placement

For decades, left ventricular ejection fraction (LVEF < 35%) has been a mainstay for identifying heart failure (HF) patients most likely to benefit from an implantable cardioverter defibrillator (ICD). However, LVEF is a poor predictor of sudden cardiac death (SCD) and ignores 50% of HF patients with mildly reduced and preserved LVEF. The current international guidelines for primary prophylaxis ICD therapy are inadequate. Instead of LVEF, which is not a good measure of LV contractility or hemodynamic characterization, we hypothesize ventriculo-arterial (VA) coupling combined with fragmented QRS (fQRS) will improve risk stratification and patient suitability for an ICD. Quantifying cardiac and aortic mechanics, and predicting active arrhythmogenic substrate, from varying fQRS morphologies, may help to stratify ischemic and non-ischemic patients with different functional capacities and predisposition for lethal arrhythmias. We propose HF patients with a low physiological reserve may not benefit from ICD therapy, whereas those patients with higher reserves and extensive arrhythmogenic substrate may benefit. Our hypothesis combining VA coupling with fQRS changes has the potential to widen HF patient participation (low and high LVEF) and advance personalized medicine for HF patients at high risk of SCD.

Mechanisms maintaining right ventricular contractility-to-pulmonary arterial elastance ratio in VA ECMO: a retrospective animal data analysis of RV-PA coupling

BACKGROUND

To optimize right ventricular-pulmonary coupling during veno-arterial (VA) ECMO weaning, inotropes, vasopressors and/or vasodilators are used to change right ventricular (RV) function (contractility) and pulmonary artery (PA) elastance (afterload). RV-PA coupling is the ratio between right ventricular contractility and pulmonary vascular elastance and as such, is a measure of optimized crosstalk between ventricle and vasculature. Little is known about the physiology of RV-PA coupling during VA ECMO. This study describes adaptive mechanisms for maintaining RV-PA coupling resulting from changing pre- and afterload conditions in VA ECMO.

METHODS

In 13 pigs, extracorporeal flow was reduced from 4 to 1 L/min at baseline and increased afterload (pulmonary embolism and hypoxic vasoconstriction). Pressure and flow signals estimated right ventricular end-systolic elastance and pulmonary arterial elastance. Linear mixed-effect models estimated the association between conditions and elastance.

RESULTS

At no extracorporeal flow, end-systolic elastance increased from 0.83 [0.66 to 1.00] mmHg/mL at baseline by 0.44 [0.29 to 0.59] mmHg/mL with pulmonary embolism and by 1.36 [1.21 to 1.51] mmHg/mL with hypoxic pulmonary vasoconstriction (p < 0.001). Pulmonary arterial elastance increased from 0.39 [0.30 to 0.49] mmHg/mL at baseline by 0.36 [0.27 to 0.44] mmHg/mL with pulmonary embolism and by 0.75 [0.67 to 0.84] mmHg/mL with hypoxic pulmonary vasoconstriction (p < 0.001). Coupling remained unchanged (2.1 [1.8 to 2.3] mmHg/mL at baseline; - 0.1 [- 0.3 to 0.1] mmHg/mL increase with pulmonary embolism; - 0.2 [- 0.4 to 0.0] mmHg/mL with hypoxic pulmonary vasoconstriction, p > 0.05). Extracorporeal flow did not change coupling (0.0 [- 0.0 to 0.1] per change of 1 L/min, p > 0.05). End-diastolic volume increased with decreasing extracorporeal flow (7.2 [6.6 to 7.8] ml change per 1 L/min, p < 0.001).

CONCLUSIONS

The right ventricle dilates with increased preload and increases its contractility in response to afterload changes to maintain ventricular-arterial coupling during VA extracorporeal membrane oxygenation.

Low Mean Perfusion Pressure Indexed to Body Surface Area is a Powerful Predictor of Poor Outcomes After Heart Transplantation in Patients With High Pre-Transplant Venous Pressure: A Clinical Study With Physiological Insights From Mathematical Modelling of Biventricular Heart Failure

BACKGROUND & AIM

The deleterious consequences of chronically elevated venous pressure in patients with profound right ventricular or biventricular dysfunction are well known, including renal and hepatic dysfunction, and volume overload. The only option for these patients, if they fail optimal medical treatment, is a heart transplant, as they are not candidates for left ventricular assist device therapy. Mean perfusion pressure (MPP) is important in the outcomes of critically ill patients with high venous pressure. The question arises whether MPP is important for the outcomes of heart transplants in patients with elevated pre-transplant venous pressure. Medical management of heart failure patients with reduced ejection fraction involves lowering the systemic afterload with vasodilators while awaiting a transplant. We hypothesised that when venous pressure is elevated prior to transplant, a substantial reduction in systemic arterial elastance (Ea) through vasodilation may significantly decrease MPP, resulting in compromised end-organ function and consequent unfavourable outcomes after heart transplantation. This study aims to investigate whether a low MPP serves as a risk factor for adverse outcomes in heart transplant recipients with high venous pressure.

METHOD

A retrospective analysis was conducted on 250 heart transplant recipients undergoing isolated heart transplantation at a single institution from October 2012 to March 2020. Right atrial pressure (RAP) of more than 15 mmHg was considered high. Additionally, Ea calculated as the ratio of end-systolic pressure to stroke volume, and MPP calculated as the difference between mean arterial pressure and RAP were considered in our analysis. The outcomes of transplantation were measured in terms of 90-day mortality and survival up to 7 years.

RESULTS

High RAP was a significant risk factor for short-term and medium-term survival if Ea was low (<2.7 mmHg/mL, the median value). This group had 39.39% in-hospital mortality compared to 14.49% for RAP<15 mmHg (p∼0.005). When Ea was high, this difference in survival was not evident: 8% for RAP<15 mmHg vs 4.8% for RAP>15 mmHg (p∼0.550). This effect was mediated through a lower MPP, and the mortality due to lower MPP increased strikingly with higher body surface area (BSA). A negative correlation was observed between MPP indexed to BSA (MPPI) and the Model for End-Stage Liver Disease score (r∼-0.3580, p<0.0001) as well as creatinine (r∼-0.3551, p<0.0001). MPPI less than 40 mmHg/m2 was associated with poorer short-term (23.2% for MPPI<40 mmHg/m2 vs 7.1% for MPPI>40 mmHg/m2, p∼0.001) and medium-term survival. The impact of high RAP and low Ea on survival was evident even on medium-term follow-up; only 30% survival at 7 years follow-up for high RAP and low Ea vs 75% for RAP<15 mmHg (p∼0.0033).

CONCLUSION

The acceptable blood pressure during vasodilator therapy in patients with high RAP needs to be higher, especially in those with higher BSA. MPPI less than 40 mmHg/m2 is a risk factor for survival, in the short and medium-term, after heart transplantation.

The Relationship of Renal Augmented Velocity Index With Ventricular-Arterial Coupling in Comparison to Renal Resistive Index: Analysis by Means of Arterial and Ventricular Elastances in Hypertensive Patients

OBJECTIVE

It's a well-known scientific statement that the heart and kidney functions are frequently tied together and the impairment of one directly alters the other. However, there exist knowledge gaps about this intricate pathophysiologic link and the exact unifying mechanism is not established. Herein, we aimed to investigate the presence of cardiorenal interaction at subclinical level while the conventional cardiac and renal clinical parameters are not disrupted yet in patients with hypertension.

METHODS

We chose a novel renal Doppler ultrasonographic parameter-augmented velocity index (Avi)-and an echocardiographic measure-ventriculoarterial coupling-which is complex to analyze but increasingly used after its acceptance about being a key determinant of cardiovascular efficiency. We recruited 137 patients without a previous history of antihypertensive medication use (47.4% women; median age, 49 years). Renal Avi, renal resistive index (RI), arterial elastance (Ea ), ventricular elastance (Ees ) and Ea /Ees (ventriculoarterial coupling) parameters were all examined.

RESULTS

Renal Avi, Ea , and Ea /Ees values were higher in females. Correlation analysis revealed that renal Avi was correlated with many hemodynamic variables including Ea and Ea /Ees . On multiple linear regression analysis, Ea and Ea /Ees remained as significant independent predictors of renal Avi but not of renal RI after adjustments for co-variables (β = 0.488, P < .001 for Ea ; β = 0.380, P < .001 for Ea /Ees ).

CONCLUSIONS

In comparison to renal RI, we suggest that renal Avi is a more reliable and promising index that can even measure subclinical changes in the cardiorenal circulation which needs to be elucidated.

Protective effects of Panax ginseng against doxorubicin-induced cardiac toxicity in patients with non-metastatic breast cancer: A randomized, double-blind, placebo-controlled clinical trial

INTRODUCTION

Anthracycline-based chemotherapy increases the risk of cancer therapeutics-related cardiac dysfunction. Recently, evidences from in vitro experiments and animal studies have shown that ginsenosides may exert cardiovascular protection against cancer therapeutics-related cardiac dysfunction. Here, we aimed to evaluate this effect in a clinical situation.

METHODS

In this randomized, double-blind, placebo-controlled clinical trial, women with non-metastatic breast cancer whose left ventricular ejection fraction was ≥ 50% were randomly assigned in 1:1 ratio to receive ginseng (1 g/day) or placebo besides standard chemotherapy. Echocardiographic measurements were performed at baseline, after the fourth, and eighth chemotherapy cycles. High-sensitive cardiac troponin I was assessed at baseline and after the 4th cycle. The primary endpoint of the study was change in left ventricular ejection fraction. Cancer therapeutics-related cardiac dysfunction was defined as a drop in left ventricular ejection fraction of ≥ 10% from baseline.

RESULTS

Results from 30 patients were included in the final analysis (15 patients in each group). In the intervention and control groups, left ventricular ejection fraction was dropped from 62.0 ± 0.9% to 60.7 ± 1.0% (difference = -1.3 ± 1.1%) and from 63.27 ± 1.1% to 58.0 ± 1.3% (difference = -5.27 ± 0.8%), respectively (difference = 3.97%, p = 0.006) at the end of the fourth cycle of chemotherapy. After the eighth cycle of chemotherapy, the mean left ventricular ejection fraction was increased by 0.8 ± 1.3% from baseline in the intervention group, whereas the placebo group experienced a reduction of -7.3 ± 1.4% (difference = 8.1%, p-value < 0.001). None of the patients in the ginseng group in comparison to 1(6.7%, p-value = 0.5) and 5 (33.3%, p-value = 0.02) patients in the placebo group developed cancer therapeutics-related cardiac dysfunction after the fourth and eighth cycles, respectively. High-sensitive cardiac troponin I levels were not significantly different between groups.

CONCLUSIONS

Prophylactic ginseng supplementation may protect against doxorubicin-induced early cancer therapeutics-related cardiac dysfunction and early decline in left ventricular ejection fraction in breast cancer patients.

Ventricular-arterial coupling (VAC) in a population-based cohort of middle-aged individuals: The STANISLAS cohort

BACKGROUND AND AIMS

Data exploring normal values of different ventricular-arterial coupling (VAC) parameters and their association with anthropometric and cardiovascular (CV) factors are scarce. We aim to report values of two different methods of VAC assessment according to age and sex and explore their association with CV factors within a large population-based cohort of middle-aged individuals.

METHODS

For 1333 (mean age 48 ± 14) individuals participating in the 4th visit of the STANISLAS cohort, VAC was assessed by two methods [1]: arterial elastance (Ea)/end-systolic elastance (Ees) and [2] Pulse wave velocity (PWV)/Global longitudinal strain (GLS).

RESULTS

The mean values of Ea/Ees and PWV/GLS were 1.06 ± 0.20 and 0.42 ± 0.12, respectively. The two methods of VAC assessment were poorly correlated (Pearson's correlation coefficient r = 0.14 (0.08; 0.19)). Increased PWV/GLS was associated with older age and a higher degree of cardiovascular risk factors (i.e., BMI, blood pressure, LDL, diabetes, hypertension) in the whole population as well as in the parent generation. In contrast, higher Ea/Ees were associated with decreasing age, and lower prevalence of risk factors in the whole cohort but neutrally associated with risk factors in the parent generation.

CONCLUSIONS

Higher PWV/GLS is significantly associated with CV factors regardless of age. In contrast, worse Ea/Ees is associated with a better CV risk profile when considering individuals aged 30 to 70 but neutrally associated with CV factors when considering only older patients. These results may suggest that PWV/GLS should preferably be used to explore VAC. In addition, age-individualized threshold of Ea/Ees should be used.

Cardiac and vascular effects of low-dose steroids during the early phase of septic shock: An echocardiographic study

Background

Low-dose steroids are known to increase arterial pressure during septic shock through restoration of vasopressor response to norepinephrine. However, their effects on cardiac performance and ventriculo-arterial coupling (VAC) have never been scrutinized during human septic shock. The aim of this study was to perform a comprehensive description of the cardiovascular effects of low-dose steroids using modern echocardiographic tools (including speckle tracking imaging).

Methods

This prospective study was conducted in the intensive care unit (ICU) of a university hospital in France. Consecutive adult patients admitted for septic shock and requiring low-dose steroid therapy were prospectively enrolled within 24 h of septic shock onset. We recorded hemodynamic and echocardiographic data to explore left ventricle (LV) contractility, loading conditions and VAC just before the initiation of low-dose steroids (50 mg intravenous hydrocortisone plus 50 μg enteral fludrocortisone) and 2–4 h after.

Results

Fifty patients [65 (55–73) years; 33 men] were enrolled. Arterial pressure, heart rate, almost all LV afterload parameters, and most cardiac contractility parameters significantly improved after steroids. VAC improved with steroid therapy and less patients had uncoupled VAC (&gt; 1.36) after (24%) than before (44%) treatment.

Conclusion

In this comprehensive echocardiographic study, we confirmed an improvement of LV afterload after initiation of low-dose steroids. We also observed an increase in LV contractility with improved cardiovascular efficiency (less uncoupling with decreased VAC).

Ventricular and Atrial Ejection Fractions are Associated with Mean Compartmental Cavity Volume in Cardiac Disease

Ejection fraction (EF) is considered to provide clinically useful information. Despite its enormous popularity, with more than 75,000 citations in PubMed, only few studies have traced the origin(s) of its foundation. This fact is surprising, as there are perhaps more papers published that criticize EF, than the number of publications that actually provide a solid (mathematical) basis for its alleged applicability. EF depends on two volume determinations, namely end-systolic volume (ESV) and end-diastolic volume (EDV). EF is defined as 1-ESV/EDV, yielding a metric without physical units. Previously we formulated a robust analytical expression for the nonlinear connection between EF and ESV. Here we extend that approach by providing a formula to illustrate that EF is strongly associated with half the sum (HS) of ESV and EDV. HS is not new, but forms a major component in the recently introduced Global Function Index. For 420 heart failure (HF) patients we found for left ventricular angio data: R(ESV, eDv) = 0.92, R(EF, ESV) = -0.90, and R(EF, HS) = -0.65. For echo (33 HF patients stages A, B, C and D): R(EF, HS) = -0.82. For the right atrium (CMRI in 21 acute myocardial infarction patients): R(EF, HS)=-0.65. For the left atrium (N=86) R (EF, hS)=-0.46. ESV indicates the level to which the ventricle is able to squeeze blood out of the cavity via pressure build-up. In contrast, EF refers to relative volume changes, not to the mechanism of pumping action. We conclude that for each cardiac compartment EF borrows its acclaimed attractiveness from the fact that for a wide patient spectrum the ESVand EDV correlate in a fairly linear manner. Attractiveness of EF features a straightforward mathematical derivation, rather than reflecting underlying physiology. Clinical Relevance - Ejection fraction (EF) is found to reflect (mean) ventricular / atrial size, and is primarily associated with end-systolic volume, which variable in turn highly correlates with diastolic volume. As a mathematical construct, EF has little affinity with "function", which is a central concept in physiology.

Overcoming the Limits of Ejection Fraction and Ventricular-Arterial Coupling in Heart Failure

Left ventricular ejection fraction (LVEF) and ventricular-arterial coupling (VAC) [VAC = Ea/Ees; Ea: effective arterial elastance; Ees: left ventricle (LV) elastance] are both dimensionless ratios with important limitations, especially in heart failure setting. The LVEF to VAC relationship is a divergent non-linear function, having a point of intersection at the specific value of 0.62, where V0 = 0 ml (V0: the theoretical extrapolated value of the volume-axis intercept at end-systolic pressure 0 mmHg). For the dilated LV, both LVEF and VAC are highly dependent on V0 which is inconclusive when derived from single-beat Ees formulas. VAC simplification should be avoided. Revisiting the relationship between systolic time intervals (STI), pressure, and volumes could provide simple-to-use guiding formulas, affordable for daily clinical practice. We have analyzed by echocardiography the hemodynamics of 21 patients with severe symptomatic heart failure with reduced ejection (HFrEF) compared to 12 asymptomatic patients (at risk of heart failure with mild structural disease). The groups were unequivocally separated by ‘classic’ measures (LVEF, LV end-systolic volume (ESV), LV mass, STI). Chen's Ees formula was weakly correlated with LVEF and indexed ESV (ESVi) but better correlated to the pre-ejection period (PEP); PEP/total ejection time (PEP/TET); systolic blood pressure/PEP (SBP/PEP) (P < 0.001). Combining the predictability of the LVEF to the determinant role of SBP/PEP on the Ees variations, we obtained: (SBP^*LVEF)/PEP mm Hg/ms, with an improved R² value (R² = 0.848; P < 0.001). The strongest correlations to VAC were for LVEF (R = −0.849; R² = 0.722) and PEP/TET (R = 0.925; R² = 0.857). By multiple regression, the VAC was strongly predicted (N = 33): (R = 0.975; R² = 0.95): VAC = 0.553–0.009^*LVEF + 3.463^*PEP/TET, and natural logarithm: Ln (VAC) = 0.147–1.4563^*DBP/SBP^*0.9–0.010^*LVEF + 4.207^*PEP/TET (R = 0.987; R² = 0.975; P = 0) demonstrating its exclusive determinants: LVEF, PEP/TET, and DBP/SBP. Considering Ea as a known value, the VAC-derived Ees formula: Ees_d ≈ Ea/(0.553–0.009^*LVEF+3.463^*PEP/TET) was strongly correlated to Chen's Ees formula (R = 0.973; R² = 0.947) being based on SBP, ESV, LVEF, and PEP/TET and no exponential power. Thus, the new index supports our hypothesis, in the limited sample of patients with HFrEF. Indices like SBP/PEP, (SBP^*LVEF)/PEP, PEP/TET, and DBP/SBP deserve further experiments, underlining the major role of the forgotten STI.

Clinical implication of intraoperative ventricular-arterial coupling in pediatric patients undergoing ventricular septal defects repair: A retrospective cohort study

BACKGROUND

Ventricular-arterial coupling is the ratio of arterial elastance to ventricular end-systolic elastance.

AIMS

The objective of this study was to determine the clinical implication of intraoperative ventricular-arterial coupling derived from the pressure-area relationship using transesophageal echocardiography.

METHODS

This retrospective study reviewed the medical records of 72 pediatric patients with ventricular septal defects who underwent corrective surgery with cardiopulmonary bypass. The single-beat modified method was used to assess ventricular-arterial coupling. Logistic regression analyses were performed to determine the correlation between ventricular-arterial coupling and early postoperative outcomes, including the maximum vasoactive-inotropic score, length of mechanical ventilation, and length of hospital stay.

RESULTS

Ventricular-arterial coupling after cardiopulmonary bypass significantly increased (from 1.0 ± 0.4 to 1.4 ± 0.8, p < .001), indicating a disproportionate increase in the arterial elastance index (from 11.5 ± 5.1 to 19.8 ± 7.5 mmHg/cm² /m² , p < .001) compared with the ventricular end-systolic elastance index (from 13.0 ± 6.9 to 16.9 ± 9.0 mmHg/cm² /m² , p < .001). Logistic regression analyses revealed that high postoperative ventricular-arterial coupling was independently associated with higher postoperative maximum vasoactive-inotropic score (>10; odds ratio [OR], 8.04; 95% confidence interval [CI], 1.38-46.85, p = .020), longer postoperative mechanical ventilation (>15 h; OR: 11.00; 95% CI: 1.26-96.45, p = .030), and longer postoperative hospital stay (>7 days; OR: 2.98; 95% CI: 1.04-8.58, p = .043).

CONCLUSIONS

Ventricular-arterial coupling can be easily obtained from the intraoperative transesophageal echocardiography in pediatric patients undergoing ventricular septal defects repair. High postoperative ventricular-arterial coupling is strongly associated with worse early postoperative outcomes. Ventricular-arterial coupling shows promise as an intraoperative analysis tool that can provide insight into the impact of interventions on cardiovascular performance and identify potential targets for treatment in this population.

Revisiting the relationship between left ventricular ejection fraction and ventricular-arterial coupling

The aim of this article was to analyse in‐depth the relationship between left ventricular (LV) ejection fraction (EF) (LVEF) and the most commonly used formulas for the calculation of LV elastance (Ees), volume intercept at 0 mmHg pressure (V0), effective arterial elastance (Ea), and ventricular–arterial coupling (VAC) as are validated today. We analyse the mathematical resulting consequences, raising the question on the physiological validity. To our knowledge, some of the following mathematical consequences have never been published. On the basis of studies demonstrating that normal LV dimensions and LVEF have a Gaussian unimodal distribution, we considered that the normal modal LVEF is 62% or very close to it. Expressed as a fraction, it is 0.62, that is, the reciprocal of the Phi number (namely, 1/Φ ~ 0.618). Applying Euclid's mathematical law on the extreme and mean ratio (the golden ratio), we studied the LVEF–VAC relationship in normal hearts. The simplification of the VAC formula (with V0 = 0) leads to false physiological results; V0 extraction from single‐beat Chen's formula leads to high negative results in normal subjects; based on the Euclid law, LVEF and Ea/Ees will be equal for a ratio value of 0.618 (62%) where V0 cannot be different from 0 mL; LVEF and VAC inverse relationship formula (Ea/Ees = 1/LVEF − 1) is reducible to a fundamental property of Phi: 1/Φ = (Φ − 1), being valid only if LVEF = VAC at a 0.618 value; according to this restriction, Vo can only be 0 mL, thus describing a very limited range. The Ea/Ees ratio, owing to its mathematical more dynamic behaviour, can be more sensitive than LVEF, being a valuable clinical tool in patients with heart failure (HF) with reduced EF, acute unstable haemodynamic situations, where Ees and Ea variations are disproportionate. However, the application is doubtful in HF with preserved EF where Ees and Ea may have same‐direction augmentation. The modified VAC formula suffers from oversimplification, reducing it to a dimensionless ratio, which is supposed to approximate non‐linear time‐varying functions. Thus, we advocate for caution and in‐depth understanding when using simplified formulas in clinical practice.