Aortic pulsatility index predicts clinical outcomes in heart failure: a sub-analysis of the ESCAPE trial

Hemodynamic management of cardiogenic shock in the intensive care unit

Hemodynamic derangements are defining features of cardiogenic shock. Randomized clinical trials have examined the efficacy of various therapeutic interventions, from percutaneous coronary intervention to inotropes and mechanical circulatory support (MCS). However, hemodynamic management in cardiogenic shock has not been well-studied. This State-of-the-Art review will provide a framework for hemodynamic management in cardiogenic shock, including a description of the 4 therapeutic phases from initial 'Rescue' to 'Optimization', 'Stabilization' and 'de-Escalation or Exit therapy' (R-O-S-E), phenotyping and phenotype-guided tailoring of pharmacological and MCS support, to achieve hemodynamic and therapeutic goals. Finally, the premises that form the basis for clinical management and the hypotheses for randomized controlled trials will be discussed, with a view to the future direction of cardiogenic shock.

PREDICT HF: Risk stratification in advanced heart failure using novel hemodynamic parameters

BACKGROUND

Invasive hemodynamics are fundamental in assessing patients with advanced heart failure (HF). Several novel hemodynamic parameters have been studied; however, the relative prognostic potential remains ill-defined.

HYPOTHESIS

Advanced hemodynamic parameters provide additional prognostication beyond the standard hemodynamic assessment.

METHODS

Patients from the PRognostic Evaluation During Invasive CaTheterization for Heart Failure (PREDICT-HF) registry who underwent right heart catheterization (RHC) were included in the analysis. The primary endpoint was survival to orthotopic heart transplant (OHT) or durable left ventricular assist device (LVAD), or death within 6 months of RHC.

RESULTS

Of 846 patients included, 176 (21%) met the primary endpoint. In a multivariate model that included traditional hemodynamic variables, pulmonary capillary wedge pressure (PCWP) (OR: 1.10, 1.04-1.15, p < .001), and cardiac index (CI) (OR: 0.86, 0.81-0.92, p < .001) were shown to be predictive of adverse outcomes. In a separate multivariate model that incorporated advanced hemodynamic parameters, cardiac power output (CPO) (OR: 0.76, 0.71-0.83, p < .001), aortic pulsatility index (API) (OR: 0.94, 0.91-0.96, p < .001), and pulmonary artery pulsatility index (OR: 1.02, 1.00-1.03, p .027) were all significantly associated with the primary outcome. Positively concordant API and CPO afforded the best freedom from the endpoint (94.7%), whilst negatively concordant API and CPO had the worst freedom from the endpoint (61.5%, p < .001). Those with discordant API and CPO had similar freedom from the endpoint.

CONCLUSION

The advanced hemodynamic parameters API and CPO are independently associated with death or the need for OHT or LVAD within 6 months. Further prospective studies are needed to validate these parameters and elucidate their role in patients with advanced HF.

Advanced hemodynamics for prognostication in heart failure: the pursuit of the patient-specific tipping point

Background

Objective tools to define the optimal time for referral for advanced therapies and to help guide escalation and de-escalation of support can improve management decisions and outcomes for patients with advanced heart failure. The current parameters have variable prognostic potential depending on the patient population being studied and often have arbitrary thresholds.

Methods

Here, a mathematical and physiological framework to define the patient-specific tipping point of myocardial energetics is defined. A novel hemodynamic parameter known as the myocardial performance score (MPS), a marker of power and efficiency, is introduced that allows for the objective assessment of the physiological tipping point. The performance of the MPS and other advanced hemodynamic parameters including aortic pulsatility index (API) and cardiac power output (CPO) in predicting myocardial energetics and the overall myocardial performance was evaluated using a validated computer simulation model of heart failure (Harvi) as well as a proof-of-concept clinical validation using a cohort of the Society for Cardiovascular Angiography and Interventions (SCAI) Stage C cardiogenic shock patients.

Results

Approximately 1010 discrete heart failure scenarios were modeled. API strongly correlated with the left ventricular coupling ratio (R2 = 0.81) and the strength of association became even stronger under loaded conditions where pulmonary capillary wedge pressure (PCWP) was >20 mmHg (R2 = 0.94). Under loaded conditions, there is a strong logarithmic relationship between MPS and mechanical efficiency (R2 = 0.93) with a precipitous rise in potential energy (PE) and drop in mechanical efficiency with an MPS <0.5. An MPS <0.5 was able to predict a CPO <0.6 W and coupling ratio of <0.7 with sensitivity (Sn) of 87%, specificity (Sp) of 91%, positive predictive value of 81%, and negative predictive value of 94%. In a cohort of 224 patients with SCAI Stage C shock requiring milrinone initiation, a baseline MPS score of <0.5 was associated with a 35% event rate of the composite endpoint of death, left ventricular assist device, or transplant at 30 days compared with 3% for those with an MPS >1 (p < 0.001). Patients who were able to augment their MPS to >1 after milrinone infusion had a lower event rate than those with insufficient reserve (40% vs. 16%, p = 0.01).

Conclusions

The MPS, which defines the patient-specific power-to-efficiency ratio and is inversely proportional to PE, represents an objective assessment of the myocardial energetic state of a patient and can be used to define the physiological tipping point for patients with advanced heart failure.

Pathophysiologic and prognostic importance of cardiac power output reserve in heart failure with preserved ejection fraction

AIMS

Heart failure with preserved ejection fraction (HFpEF) is a syndrome characterized by multiple cardiac reserve limitations during exercise. Cardiac power output (CPO) is an index of global cardiac performance and can be estimated non-invasively by echocardiography. We hypothesized that CPO reserve during exercise would be associated with impaired cardiovascular reserve, exercise intolerance, and adverse outcomes in HFpEF.

METHODS AND RESULTS

Exercise stress echocardiography was performed in 425 dyspnoeic patients [217 HFpEF and 208 non-heart failure (HF) controls] to estimate CPO at rest and during exercise. We classified patients with HFpEF based on the median value of changes in CPO from rest to peak exercise (ΔCPO >0.49 W/100 g). Patients with HFpEF and a lower CPO reserve had poorer biventricular systolic function, impaired chronotropic response during exercise, and worse aerobic capacity than controls and those with a higher CPO reserve. During a median follow-up of 358 days, a composite outcome of all-cause mortality or HF events occurred in 30 patients. Patients with a lower CPO reserve had four-fold and nearly 10-fold increased risks of the outcomes compared with those with a higher CPO reserve and controls, respectively [hazard ratio (HR) 4.05, 95% confidence interval (CI) 1.16-10.1, P = 0.003 and HR 9.61, 95% CI 3.58-25.8, P < 0.0001]. We further found that a lower CPO reserve had an incremental prognostic value over the H2FPEF score and exercise duration. In contrast, resting CPO did not predict clinical outcomes in patients with HFpEF.

CONCLUSION

A lower CPO reserve was associated with biventricular systolic dysfunction, chronotropic incompetence, exercise intolerance, and adverse outcomes in patients with HFpEF.

Standardization of the Right Heart Catheterization and the Emerging Role of Advanced Hemodynamics in Heart Failure

The accurate assessment of hemodynamics is paramount to providing timely and efficacious care for patients presenting in cardiogenic shock. Recently, the regular use of the pulmonary artery catheter in cardiogenic shock has had a resurgence with emerging data indicating improved survival in the modern era. Optimal multidisciplinary management of advanced heart failure and cardiogenic shock relies on our ability to effectively communicate and understand the complete hemodynamic assessment. Standardization of data acquisition and a renewed focus on the physiological processes, and thresholds driving disease progression, including the coupling ratio and myocardial reserve, are needed to fully understand and interpret the hemodynamic assessment. This State-of-the-Art review discusses best practices in the cardiac catheterization laboratory as well as emerging data on the prognostic role of emerging advanced hemodynamic parameters.

Management of Cardiogenic Shock Unrelated to Acute Myocardial Infarction

Cardiogenic shock is an extreme manifestation of acute decompensated heart failure. Cardiogenic shock is often caused by-and has traditionally been studied in the setting of-acute myocardial infarction (AMI CS); however, there is increasing incidence and recognition of cardiogenic shock not associated with acute myocardial infarction (non-AMI CS) as a distinct entity. Despite decades of study and technologic advancements, cardiogenic shock mortality remains as high as 50%, regardless of etiology. New approaches to shock phenotyping and classification have emerged, with a focus on appropriately matching patient physiology to a growing list of available interventions. Further study is needed to determine whether these efforts will lead to more nuanced use of mechanical circulatory support and improved patient outcomes, especially in non-AMI CS. In the meantime, models of care incorporating multidisciplinary decision making, such as shock teams, may improve patient selection and outcomes.

Aortic Pulsatility Index: A New Haemodynamic Measure with Prognostic Value in Advanced Heart Failure

Aim: To test if the newly described haemodynamic variable, aortic pulsatility index (API), predicts long-term prognosis in advanced heart failure (HF). Methods: A single-centre study on 453 HF patients (median age: 51 years; left ventricular ejection fraction [LVEF]: 19% ± 9%) referred for right heart catheterisation. API was calculated as pulse pressure/pulmonary capillary wedge pressure. Results: Log(API) correlated significantly with central venous pressure (CVP; p<0.001) and cardiac index (p<0.001) in univariable regression analysis. CVP remained associated with log(API) in a multivariable analysis including cardiac index, heart rate, log(NT-proBNP [N-terminal proB-type natriuretic peptide]), LVEF, New York Heart Association (NYHA) class III or IV and sex (p=0.01). In univariable Cox models, log(API) was a significant predictor of freedom from the combined endpoint of death, left ventricular assist device implantation, total artificial heart implantation or heart transplantation (HR 0.33; (95% CI [0.22–0.49]); p<0.001) and all-cause mortality (HR 0.56 (95% CI [0.35–0.90]); p=0.015). After adjusting for age, sex, NYHA class III or IV and estimated glomerular filtration rate in multivariable Cox models, log(API) remained a significant predictor for the combined endpoint (HR 0.33; 95% CI [0.20–0.56]; p<0.001) and all-cause mortality (HR 0.49; 95% CI [0.26–0.96]; p=0.034). Conclusion: API was strongly associated with right-sided filling pressure and independently predicted freedom from the combined endpoint and all-cause mortality.

Improved Prognostic Performance of Cardiac Power Output With Right Atrial Pressure: A Subanalysis of the ESCAPE Trial

BACKGROUND

The initial derivation of cardiac power output (CPO) included the difference between mean arterial pressure (MAP) and right atrial pressure (RAP) in the numerator, before multiplying by cardiac output (CO). We hypothesized that the inclusion of RAP (CPO-RAP) would enhance the prognostic performance of this parameter in those with an elevated RAP.

METHODS AND RESULTS

We obtained patient-level data from the ESCAPE trial via the Biolincc database. Participants with full final hemodynamics were included in the analysis. The CPO-RAP was calculated as [(MAP - RAP) × CO)]/451 Watts (W), and the CPO was calculated as (MAP × CO)/451. The primary outcome was freedom from left ventricular assist device, heart transplant, or death at 6 months. Included participants (n = 157) were a median of 58 years of age (interquartile range [IQR] 49-67 years), 27% were women, and 59% had ischemic cardiomyopathy. The median CPO was 0.70 W (IQR 0.50-0.90 W), and the median CPO-RAP was 0.62 W (IQR 0.47-0.79 W). In univariable logistic regressions, the CPO was not associated with the primary outcome (odds ratio 0.32, 95% confidence interval 0.08-1.29, P = .11), but the CPO-RAP was (odds ratio 0.10, 95% confidence interval 0.02-0.54, P < .01). In Kaplan-Meier analyses, there were no significant difference in outcomes with CPO (76% vs 64%, P = .08), but for CPO-RAP, there were significant differences in outcomes (81% vs 63%, P = .01). When further delineating CPO-RAP by RAP above or below the median, there was no significant difference in the outcome for participants with a RAP 8 or less (94% vs 79%, P = .07), but a significant difference in participants with a RAP of more than 8 mm Hg (66% vs 45%, P < .05).

CONCLUSIONS

The inclusion of RAP resulted in a significant association with the primary outcome; CPO alone was not.

Aortic pulsatility index predicts clinical outcomes in heart failure: a sub-analysis of the ESCAPE trial

AIMS

Aortic pulsatility index (API), calculated as (systolic-diastolic blood pressure)/pulmonary capillary wedge pressure (PCWP), is a novel haemodynamic measurement representing both cardiac filling pressures and contractility. We hypothesized that API would better predict clinical outcomes than traditional haemodynamic metrics of cardiac function.

METHODS AND RESULTS

The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial individual-level data were used. Routine haemodynamic measurements, including Fick cardiac index (CI), and the advanced haemodynamic metrics of API, cardiac power output (CPO), and pulmonary artery pulsatility index (PAPI) were calculated after final haemodynamic-monitored optimization. The primary outcome was a composite endpoint of death or need for orthotopic heart transplant (OHT) or left ventricular assist device (LVAD) at 6 months. A total of 433 participants were enrolled in the ESCAPE trial of which 145 had final haemodynamic data. Final API measurements predicted the primary outcome, OR 0.47 (95% CI 0.32-0.70, P < 0.001), while CI, CPO, and PAPI did not. Receiver operator characteristic analyses of final advanced haemodynamic measurements indicated API best predicted the primary outcome with a cutoff of 2.9 (sensitivity 76.2%, specificity 55.3%, correctly classified 61.4%, area-under-the-curve 0.71), compared with CPO, CI, and PAPI. Kaplan-Meier analyses indicated API ≥ 2.9 was associated with greater freedom from the primary outcome (83.5%), compared with API < 2.9 (58.4%), P = 0.001. While PAPI was also significantly associated, CI and CPO were not.

CONCLUSIONS

The novel haemodynamic measurement API better predicted clinical outcomes in the ESCAPE trial when compared with traditional invasive haemodynamic metrics of cardiac function.