Impact of Interventricular Interaction on Ventricular Function: Insights From Right Ventricular Pressure-Volume Analysis.

BACKGROUND: Interventricular interactions may be responsible for the decline in ventricular performance observed in various disease states that primarily affect the contralateral ventricle. OBJECTIVES: This study sought to quantify the impact of such interactions on right ventricular (RV) size and function using clinically stable individuals with left ventricular assist devices (LVADs) as a model for assessing RV hemodynamics while LV loading conditions were acutely manipulated by changing device speed during hemodynamic optimization studies (ie, ramp tests). METHODS: The investigators recorded RV pressure-volume loops with a conductance catheter at various speeds during ramp tests in 20 clinically stable HeartMate3 recipients. RESULTS: With faster LVAD speeds and greater LV unloading, indexed RV end-diastolic volume increased (72.28 ± 15.07 mL at low speed vs 75.95 ± 16.90 at high speed; P = 0.04) whereas indexed end-systolic volumes remained neutral. This resulted in larger RV stroke volumes and shallower end-diastolic pressure-volume relationships. Concurrently, RV end-systolic pressure decreased (31.58 ± 9.75 mL at low speed vs 29.58 ± 9.41 mL at high speed; P = 0.02), but contractility, as measured by end-systolic elastance, did not change significantly. The reduction in RV end-systolic pressure was associated with a reduction in effective arterial elastance from 0.65 ± 0.43 mm Hg/mL at low speed to 0.54 ± 0.33 mm Hg/mL at high speed (P = 0.02). CONCLUSIONS: Interventricular interactions resulted in improved RV compliance, diminished afterload, and did not reduce RV contractility. These data challenge the prevailing view that interventricular interactions compromise RV function, which has important implications for the understanding of RV-LV interactions in various disease states, including post-LVAD RV dysfunction.

Mitral Interventions in Heart Failure.

Patients with heart failure with reduced ejection fraction who have secondary mitral regurgitation (SMR) have poorer outcomes and quality of life than those without SMR. Guideline-directed medical therapy is the cornerstone of SMR treatment. Careful evaluation of landmark trials using mitral transcatheter edge-to-edge repair in SMR has led to an improved understanding of who will benefit from percutaneous interventions with emphasis on a multidisciplinary approach. The success with mitral transcatheter edge-to-edge repair in SMR has also spurred the evaluation of its role in populations that were not initially studied, such as end-stage heart failure and cardiogenic shock. A spectrum of transcatheter devices in development and clinical trials promise to further provide a growing array of management options for heart failure with reduced ejection fraction patients with symptomatic SMR.

Tricuspid Regurgitation Management for Heart Failure.

There is growing evidence that severe tricuspid regurgitation (TR) impacts clinical outcomes in a variety of cardiovascular disease states. The late presentation of patients with advanced TR highlights the underappreciation of the disease, as well as the pitfalls of current guideline-directed medical management. Given the high in-hospital mortality associated with isolated tricuspid valve surgery, transcatheter options continue to be explored with the hope of improved survival and reduced heart failure hospitalizations. In this review, we explore the physiology of TR, discuss the etiologic classes of TR, and explore the transcatheter options for treatment and who might benefit from device therapy.

Stressed Blood Volume in Severe Tricuspid Regurgitation: Implications for Transcatheter Treatment.

BACKGROUND: Although tricuspid transcatheter edge-to-edge repair (TEER) has been suggested to improve outcomes in patients with tricuspid regurgitation (TR), patients remain at substantial residual risk after the intervention. Total blood volume is divided between the unstressed volume, filling the vascular space, and stressed blood volume (SBV), generating intravascular pressure. SBV is an important mediator of hemodynamic derangements in heart failure and might pose an attractive adjunctive treatment target. OBJECTIVES: The aim of this study was to investigate the role of SBV in patients with severe TR and its implications for tricuspid TEER. METHODS: In total, 279 patients underwent right heart catheterization prior to TEER. SBV was estimated from hemodynamic variables fit to a comprehensive cardiovascular model. RESULTS: Estimated stressed blood volume (eSBV) was associated with obesity, renal and hepatic dysfunction and cardiac remodeling (P < 0.05 for all). Hemodynamically, eSBV correlated with pulmonary artery and cardiac filling pressures as well as right ventricular-pulmonary artery coupling (P < 0.05 for all). After TEER, patients with eSBV greater than the median demonstrated less reduction in right atrial pressures, peripheral edema, and ascites compared with lower eSBV patients (P < 0.05 for all). Higher eSBV was an independent predictor of the occurrence of death and heart failure hospitalization during a median follow-up duration of 618 days (P < 0.05 for all). CONCLUSIONS: In patients with severe TR, eSBV is associated with obesity, renal and liver dysfunction, more severe heart failure, attenuated reduction of venous congestion after TEER, and adverse clinical outcomes. Estimation of SBV should be incorporated in future trials in the field to identify patients in need of adjunctive therapies.

Long-Term Outcomes of Randomized Controlled Trials Comparing Percutaneous Left Atrial Appendage Closure to Oral Anticoagulation for Nonvalvular Atrial Fibrillation: A Meta-Analysis.

Background: Oral anticoagulation (OAC) has been considered the standard of care for stroke prophylaxis for patients with nonvalvular atrial fibrillation; however, many individuals are unable or unwilling to take long-term OAC. The safety and efficacy of percutaneous left atrial appendage closure (LAAC) have been controversial, and new trial data have recently emerged. We therefore sought to perform an updated meta-analysis of randomized clinical trials (RCTs) comparing OAC to percutaneous LAAC, focusing on individual clinical endpoints. Methods: We performed a systematic search of the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials from January 2000 through December 2021 for all RCTs comparing percutaneous LAAC to OAC in patients with nonvalvular atrial fibrillation. Fixed and random effects meta-analyses of hazard ratios (HRs) were performed using the longest follow-up duration available by intention-to-treat. The prespecified primary endpoint was all-cause mortality. Results: Three RCTs enrolling 1516 patients were identified. The weighted mean follow-up was 54.7 months. LAAC was associated with a reduced risk of all-cause mortality (HR 0.76; 95% confidence interval [CI], 0.59-0.96; p = 0.023), hemorrhagic stroke (HR 0.24; 95% CI, 0.09-0.61; p = 0.003), and major nonprocedural bleeding (HR 0.52; 95% CI, 0.37-0.74; p < 0.001). There was no significant difference between LAAC and OAC for any other endpoints. Conclusions: The available evidence from RCTs suggests LAAC therapy is associated with reduced long-term risk of death compared with OAC. This may be driven by reductions in hemorrhagic stroke and major nonprocedural bleeding. There were no significant differences in the risk of all stroke. Further large-scale clinical trials are needed to validate these findings.

Baseline Characteristics and Clinical Outcomes of a Tricuspid Regurgitation Referral Population.

Adverse outcomes in tricuspid regurgitation (TR) have been associated with advanced regurgitation severity and right-sided cardiac remodeling, and late referrals for tricuspid valve surgery in TR have been associated with increase in postoperative mortality. The purpose of this study was to evaluate baseline characteristics, clinical outcomes, and procedural utilization of a TR referral population. We analyzed patients with a diagnosis of TR referred to a large TR referral center between 2016 and 2020. We evaluated baseline characteristics stratified by TR severity and analyzed time-to-event outcomes for a composite of overall mortality or heart-failure hospitalization. In total, 408 patients were referred with a diagnosis of TR: the median age of the cohort was 79 years (interquartile range 70 to 84), and 56% were female. In patients evaluated on a 5-grade scale, 10.2% had ≤moderate TR; 30.7% had severe TR; 11.4% had massive TR, and 47.7% had torrential TR. Increasing TR severity was associated with right-sided cardiac remodeling and altered right ventricular hemodynamics. In multivariable Cox regression analysis, New York Heart Association class symptoms, history of heart failure hospitalization, and right atrial pressure were associated with the composite outcome. One-third of patients referred underwent transcatheter tricuspid valve intervention (19%) or surgery (14%); patients who underwent transcatheter tricuspid valve intervention had greater preoperative risk than that of patients who underwent surgery. In conclusion, in patients referred for evaluation of TR, there were high rates of massive and torrential regurgitation and advanced right ventricle remodeling. Symptoms and right atrial pressure are associated with clinical outcomes in follow-up. There were significant differences in baseline procedural risk and eventual therapeutic modality.

Early outcomes following transatrial transcatheter mitral valve replacement in patients with severe mitral annular calcification.

OBJECTIVE: Implantation of a transcatheter valve-in-mitral annular calcification (ViMAC) has emerged as an alternative to traditional surgical mitral valve (MV) replacement. Previous studies evaluating ViMAC aggregated transseptal, transapical, and transatrial forms of the procedure, leaving uncertainty about each technique's advantages and disadvantages. Thus, we sought to evaluate clinical outcomes specifically for transatrial ViMAC from the largest multicenter registry to-date. METHODS: Patients with symptomatic MV dysfunction and severe MAC who underwent ViMAC were enrolled from 12 centers across the United States and Europe. Clinical characteristics, procedural details, and clinical outcomes were abstracted from the electronic record. The primary end point was all-cause mortality. RESULTS: We analyzed 126 patients who underwent ViMAC (median age 76 years [interquartile range {IQR}, 70-82 years], 28.6% female, median Society of Thoracic Surgeons score 6.8% [IQR, 4.0-11.4], and median follow-up 89 days [IQR, 16-383.5]). Sixty-one (48.4%) had isolated mitral stenosis, 25 (19.8%) had isolated mitral regurgitation (MR), and 40 (31.7%) had mixed MV disease. Technical success was achieved in 119 (94.4%) patients. Thirty (23.8%) patients underwent concurrent septal myectomy, and 8 (6.3%) patients experienced left ventricular outflow tract obstruction (7/8 did not undergo myectomy). Five (4.2%) patients of 118 with postprocedure echocardiograms had greater than mild paravalvular leak. Thirty-day and 1-year all-cause mortality occurred in 16 and 33 patients, respectively. In multivariable models, moderate or greater MR at baseline was associated with increased risk of 1-year mortality (hazard ratio, 2.31; 95% confidence interval, 1.07-4.99, P = .03). CONCLUSIONS: Transatrial ViMAC is safe and feasible in this selected, male-predominant cohort. Patients with significant MR may derive less benefit from ViMAC than patients with mitral stenosis only.

Right-Sided Mechanical Circulatory Support - A Hemodynamic Perspective.

PURPOSE OF REVIEW: Right ventricular (RV) failure is increasingly recognized as a major cause of morbidity and mortality. When RV failure is refractory to medical therapy, escalation to right-sided mechanical circulatory support (MCS) should be considered. In this review, we begin by recapitulating the hemodynamics of RV failure, then we delve into current and future right-sided MCS devices and describe their hemodynamic profiles. RECENT FINDINGS: The field of temporary right-sided MCS continues to expand, with evolving strategies and new devices actively under development. All right-sided MCS devices bypass the RV, with each bypass configuration conferring a unique hemodynamic profile. Devices that aspirate blood directly from the RV, as opposed to the RA or the IVC, have more favorable hemodynamics and more effective RV unloading. There has been a growing interest in single-access MCS devices which do not restrict patient mobility. Additionally, a first-of-its-kind percutaneous, pulsatile, right-sided MCS device (PERKAT RV) is currently undergoing investigation in humans. Prompt recognition of refractory RV failure and deployment of right-sided MCS can improve outcomes. The field of right-sided MCS is rapidly evolving, with ongoing efforts dedicated towards developing novel temporary devices that are single access, allow for patient mobility, and directly unload the RV, as well as more durable devices.

Epidemiology and management of right ventricular-predominant heart failure and shock in the cardiac intensive care unit.

Cardiogenic shock from left ventricular failure is a common presentation in the intensive care unit. In contrast, right ventricular (RV)-predominant heart failure (HF) causing shock is less well recognized. We review the epidemiology and mechanisms of RV-predominant HF and discuss pharmacologic and device-based approaches for the management of this challenging clinical problem.

Venous Tone and Stressed Blood Volume in Heart Failure: JACC Review Topic of the Week.

A number of pathologic processes contribute to the elevation in cardiac filling pressures in heart failure (HF), including myocardial dysfunction and primary volume overload. In this review, we discuss the important role of the venous system and the concepts of stressed blood volume and unstressed blood volume. We review how regulation of venous tone modifies the distribution of blood between these 2 functional compartments, the physical distribution of blood between the pulmonary and systemic circulations, and how these relate to the hemodynamic abnormalities observed in HF. Finally, we review recently applied methods for estimating stressed blood volume and how they are being applied to the results of clinical studies to provide new insights into resting and exercise hemodynamics and therapeutics for HF.

Right Ventricular-Pulmonary Arterial Coupling and Afterload Reserve in Patients Undergoing Transcatheter Tricuspid Valve Repair.

BACKGROUND: The right ventricular (RV)-pulmonary arterial (PA) coupling ratio relates the efficiency with which RV stroke work is transferred into the PA. Lower ratios indicate an inadequate RV contractile response to increased afterload. OBJECTIVES: This study sought to evaluate the prognostic significance of RV-PA coupling in patients with tricuspid regurgitation (TR) who were undergoing transcatheter tricuspid valve repair or replacement (TTVR). METHODS: The study investigators calculated RV-PA coupling ratios for patients enrolled in the global TriValve registry by dividing the tricuspid annular plane systolic excursion (TAPSE) by the PA systolic pressure (PASP) from transthoracic echocardiograms performed before the procedure and 30 days after the procedure. The primary endpoint was all-cause mortality at 1-year follow-up. RESULTS: Among 444 patients analyzed, their mean age was 76.9 ± 9.1 years, and 53.8% of the patients were female. The median TAPSE/PASP ratio was 0.406 mm/mm Hg (interquartile range: 0.308-0.567 mm/mm Hg). Sixty-three patients died within 1 year of TTVR, 21 with a TAPSE/PASP ratio >0.406 and 42 with a TAPSE/PASP ratio ≤0.406. In multivariable Cox regression analysis, a TAPSE/PASP ratio >0.406 vs ≤0.406 was associated with a decreased risk of all-cause mortality (HR: 0.57; 95% CI: 0.35-0.93; P = 0.023). In 234 (52.7%) patients with echocardiograms 30 days after TTVR, a decline in RV-PA coupling was independently associated with reduced odds of all-cause mortality (odds ratio [OR]: 0.42; 95% CI: 0.19-0.93; P = 0.032). The magnitude of TR reduction after TTVR (≥1+ vs <1+; OR: 2.53; 95% CI: 1.06-6.03; P = 0.037) was independently associated with a reduction in post-TTVR RV-PA coupling. CONCLUSIONS: RV-PA coupling is a powerful, independent predictor of all-cause mortality in patients with TR undergoing TTVR. These data suggest that the TAPSE/PASP ratio can inform patient selection and prognostication following TTVR.

Incidence and predictors of cardiogenic shock following surgical or transcatheter tricuspid valve intervention.

OBJECTIVE: The objective of this study was to evaluate the incidence of and risk factors associated with cardiogenic shock (CS) following surgery versus transcatheter tricuspid valve intervention (TTVI) for tricuspid regurgitation (TR). BACKGROUND: Surgical therapy for TR is associated with high rates of CS. Postprocedural shock has not been studied following TTVI. METHODS: We performed a single-center retrospective analysis of isolated tricuspid valve (TV) surgery or TTVI for TR. The primary outcome was postprocedural class D or E CS according to Society for Cardiovascular Angiography and Interventions (SCAI) CS classification scheme, and secondary outcome was in-hospital mortality. Multivariable logistic regression modeling was performed for primary and secondary outcomes. Support vector machine analysis was performed for sensitivity analysis. RESULTS: From 2008 to 2020, a total of 122 patients underwent isolated TV surgery (n = 58, 14 TV repair, and 44 TV replacement) or TTVI (n = 64, 36 TV repair, and 28 TV replacement). Surgical patients were significantly younger than TTVI patients (67.5 vs. 80 years, p < 0.0001). Multivariable modeling revealed an association between the primary outcome and surgery (odds ratio [OR]: 8.75, 95% confidence interval [CI]: 2.83, 27.03, p = 0.0002), as well as baseline central venous pressure (CVP, OR: 1.12, 95% CI: 1.02, 1.22, p = 0.016). Additionally, class DE CS was independently associated with in-hospital mortality (OR: 5.21, 1.35, 20.09, p = 0.016). CVP and surgery were found to have highest importance indices in support vector machine analysis. CONCLUSION: In patients undergoing TV intervention for TR, surgery versus TTVI and elevated CVP are associated with advanced postprocedural CS. Patients developing advanced CS are at increased risk of in-hospital mortality.

Impella percutaneous left ventricular assist device as mechanical circulatory support for cardiogenic shock: A retrospective analysis from a tertiary academic medical center.

OBJECTIVES: To describe hemodynamic efficacy and clinical outcomes of Impella percutaneous left ventricular assist device (pLVAD) in patients with cardiogenic shock (CS). BACKGROUND: Percutaneous LVADs are increasingly used in CS management. However, device-related outcomes and optimal utilization remain active areas of investigation. METHODS: All CS patients receiving pLVAD as mechanical circulatory support (MCS) between 2011 and 2017 were identified. Clinical characteristics and outcomes were analyzed. A multivariable logistic regression model was created to predict MCS escalation despite pLVAD. Outcomes were compared between early and late implantation. RESULTS: A total of 115 CS patients (mean age 63.6 ± 13.8 years; 69.6% male) receiving pLVAD as MCS were identified, the majority with CS secondary to acute myocardial infarction (AMI; 67.0%). Patients experienced significant cardiac output improvement (median 3.39 L/min to 3.90 L/min, p = .002) and pharmacological support reduction (median vasoactive-inotropic score [VIS] 25.4 to 16.4, p = .049). Placement of extracorporeal membrane oxygenation (ECMO) occurred in 48 (41.7%) of patients. Higher pre-pLVAD VIS was associated with subsequent MCS escalation in the entire cohort and AMI subgroup (OR 1.27 [95% CI 1.02-1.58], p = .034 and OR 1.72 [95% CI 1.04-2.86], p = .035, respectively). Complications were predominantly access site related (bleeding [9.6%], vascular injury [5.2%], and limb ischemia [2.6%]). In-hospital mortality was 57.4%, numerically greater survival was noted with earlier device implantation. CONCLUSIONS: Treatment with pLVAD for CS improved hemodynamic status but did not uniformly obviate MCS escalation. Mortality in CS remains high, though earlier device placement for appropriately selected patients may be beneficial.

Clinico-histopathologic and single-nuclei RNA-sequencing insights into cardiac injury and microthrombi in critical COVID-19.

Acute cardiac injury is prevalent in critical COVID-19 and associated with increased mortality. Its etiology remains debated, as initially presumed causes - myocarditis and cardiac necrosis - have proved uncommon. To elucidate the pathophysiology of COVID-19-associated cardiac injury, we conducted a prospective study of the first 69 consecutive COVID-19 decedents at CUIMC in New York City. Of 6 acute cardiac histopathologic features, presence of microthrombi was the most commonly detected among our cohort. We tested associations of cardiac microthrombi with biomarkers of inflammation, cardiac injury, and fibrinolysis and with in-hospital antiplatelet therapy, therapeutic anticoagulation, and corticosteroid treatment, while adjusting for multiple clinical factors, including COVID-19 therapies. Higher peak erythrocyte sedimentation rate and C-reactive protein were independently associated with increased odds of microthrombi, supporting an immunothrombotic etiology. Using single-nuclei RNA-sequencing analysis on 3 patients with and 4 patients without cardiac microthrombi, we discovered an enrichment of prothrombotic/antifibrinolytic, extracellular matrix remodeling, and immune-potentiating signaling among cardiac fibroblasts in microthrombi-positive, relative to microthrombi-negative, COVID-19 hearts. Non-COVID-19, nonfailing hearts were used as reference controls. Our study identifies a specific transcriptomic signature in cardiac fibroblasts as a salient feature of microthrombi-positive COVID-19 hearts. Our findings warrant further mechanistic study as cardiac fibroblasts may represent a potential therapeutic target for COVID-19-associated cardiac microthrombi.

Invasive Right Ventricular Pressure-Volume Analysis: Basic Principles, Clinical Applications, and Practical Recommendations.

Right ventricular pressure-volume (PV) analysis characterizes ventricular systolic and diastolic properties independent of loading conditions like volume status and afterload. While long-considered the gold-standard method for quantifying myocardial chamber performance, it was traditionally only performed in highly specialized research settings. With recent advances in catheter technology and more sophisticated approaches to analyze PV data, it is now more commonly used in a variety of clinical and research settings. Herein, we review the basic techniques for PV loop measurement, analysis, and interpretation with the aim of providing readers with a deeper understanding of the strengths and limitations of PV analysis. In the second half of the review, we detail key scenarios in which right ventricular PV analysis has influenced our understanding of clinically relevant topics and where the technique can be applied to resolve additional areas of uncertainty. All told, PV analysis has an important role in advancing our understanding of right ventricular physiology and its contribution to cardiovascular function in health and disease.